3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-1



## Chapter 2. Agriculture 1

2. 

### Contents 2
1

. Purpose and Overview ..............................

................................................... .......................... 2-3 3 1.1 Need for Agricultural Chapter Update...........

................................................... ............ 2-3 4 1.1.1 Purpose......................................

................................................... ........................ 2-3 5
1.1.2 Intended Audience ............................

................................................... ................ 2-3 6 1.1.3 Water Quality Significance of Agricultural Ru noff in the Chesapeake Bay 7 Watershed ..........................................

................................................... ............... 2-3 8 1.1.4 Managing Agricultural Runoff to Reduce Nutrie nt and Sediment Loss.............. 2-5 9 1.2 Overview of the Agriculture Chapter ............

................................................... ............ 2-6 10 1.2.1 Management Practices and Management Practice Systems ................................ 2-6 11 1.2.2 Implementation Measures for Agriculture in th e Chesapeake Bay Watershed 12 to Control Nonpoint Source Nutrient and Sediment Po llution............................ 2-9 13
2

. Implementation Measures and practices for Source C ontrol and Avoidance...................... 2-11 14 2.1 Row Crop Agriculture...........................

................................................... ................... 2-11 15 2.1.1 Nutrient Management ..........................

................................................... ........... 2-15 16 2.1.2 Alternative Crops............................

................................................... ................ 2-20 17
2.1.3 Land Retirement..............................

................................................... ................ 2-20 18 2.1.4 Chemical Fertilizer Application, Storage, and Transport .................................. 2-21 19 2.2 Animal Agriculture .............................

................................................... ..................... 2-22 20 2.2.1 Animal Feed Management.......................

................................................... ....... 2-23 21 2.2.2 Manure Storage, and Transport................

................................................... ....... 2-26 22
2.2.3 Livestock Exclusion from Streams .............

................................................... .... 2-27 23
2.2.4 Wastewater and Animal Wastes .................

................................................... .... 2-29 24 3 Implementation Measures and Practices for In-fiel d Control.......................................... .... 2-48 25 3.1 Field Nutrient Management ......................

................................................... ............... 2-48 26
3.2 Sediment and Erosion Control...................

................................................... .............. 2-62 27 3.3 Cover Crops ....................................

................................................... ......................... 2-72 28 3.4 Pasture Land Management........................

................................................... ............... 2-76 29 3.5 Drainage System Design.........................

................................................... ................. 2-83 30
4

. Implementation Measures and Practices for Edge

- of

- Field Trapping and Treatment....... 2-87 313/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-2 4.1 Buffers and Minimum Setbacks...................

................................................... ............ 2-87 1
4.2 Wetlands .......................................

................................................... ......................... 2-100 2 4.3 Drainage Water Management ......................

................................................... .......... 2-109 3 4.4 Animal Feeding Operations ......................

................................................... ............. 2-121 4
5

. References........................................

................................................... ............................... 2-127 5 Appendix 1: USDA Conservation Practice Standards (Practice Codes) Referenced 6 throughout the document

................................................... ................................................ 2-1 56 7 Appendix 2: Agricultural Tools in Support of Sectio n 502 Technical Guidance.................... 2-165 8
I. Software and Models .............................

................................................... ................ 2-168 9 II. Calculators, Spreadsheets, and Graphical Tools.

................................................... ... 2-174 10 III. Compilations of Tools.........................

................................................... ................... 2-176 11
IV. Guidance and Other Technical Resources .........

................................................... .... 2-177 12

133/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-3 

## 1

. Purpose and Overview 1


### 1.1 Need for Agricultural Chapter Update 2



### 1.1.1 Purpose 3 Approximately 87,000 farm operations and 8.5 millio n acres of cropland, or nearly a quarter of 4 the watershed, in the Chesapeake Bay watershed prov ide food and fiber, as well as significant 5 natural areas and aesthetic and environmental benef its. Farms in the Chesapeake Bay watershed 6 are very diverse. They vary greatly in size and pro duce a wide variety of products. Today, 7 according to the U.S. Department of Agriculture (US DA), more than 50 commodities are 8 produced in this region. The area’s primary crops i nclude corn, soybeans, wheat, hay, pasture, 9 vegetables, and fruits. The eastern part of the reg ion is also home to a rapidly expanding nursery 10 and greenhouse industry. 11
This chapter’s The purpose of this chapter is to provide a host of cost-effective practices an d 12 actions that can be employed to reduce the input of nitrogen (N) , phosphorus (P) , and sediment 13 from agricultural activities to local waters and th e Chesapeake Bay. The This chapter focuses on 14 nutrient management on row crop lands and in the pr oduction area of animal feeding operations 15 (AFOs) and on the prevention of soil erosion from row crop lands. For information regarding the 16 management of agricultural lands to protect and res tore water quality by reducing impacts from 17 pesticides, irrigation, and grazing, see the user should reference the chapters devoted to those 18 activities in the National Management Measurers for the Control of No npoint Pollution from 19 Agriculture (USEPA
, 2003). 20



### 1.1.2 Intended Audience 21 This chapter of this guidance is written for a broad audience, namely
, all those involved in the 22 planning, managing management , and implementing implementation of agricultural activities. 23 This document guidance should be useful for USDA, including local Natural Resources 24 Conservation Service ( NRCS ) staff, NRCS conservation practice standard develop ers, and 25 Conservation Districts as they work hand-in-hand wi th the producers in their respective counties 26 and watersheds. This chapter is also intended to be a useful tool for nutrient management 27 planners, technical service providers (TSPs), farm operators, land land owners, and drainage 28 district staff. The document guidance also provides assistance to those planning and pro tecting or 29 restoring areas of concern, such as TMDL developers and nonpoint source planners. Finally, this 30 chapter can also provide citizens with a better und erstanding of how agricultural activities can be 31 managed to protect and restore the Chesapeake Bay. 32



### 1.1.3 Water Quality Significance of Agricultural Ru noff in the Chesapeake 33 

### Bay Watershed 34 Agriculture is the single largest source of nutrien ts and sediments to the Chesapeake Bay, 35 responsible for 43 percent of the N nitrogen , 45 percent of the P phosphorus , and 60 percent of the 36 sediment loads. Much of that this load is delivered from Pennsylvania (Susquehanna R iver), 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-4 Virginia (Shenandoah and Potomac rivers Rivers ), and the Delmarva Peninsula of Maryland, 1 Delaware
, and Virginia. Chemical fertilizer accounts for 17 percent of the N nit rogen and 19 2 percent of the P phosphorus load, and manure accounts for 19 percent of the N nitrogen and 26 3 percent of the P phosphorus load. Seven percent of the total nitrogen (TN) load comes from air 4 deposition from livestock and soil emissions from a griculture. 5 Implementing agricultural management practices might may not provide nutrient load reductions 6 to the Chesapeake Bay as quickly as implementing actions by other sec tors; however, reductions 7 in agricultural loads are the most cost-effective m eans to restore the bay Bay over time. Excess 8 N nitrogen from cropland is transported to the bay Bay via groundwater with a lag time of years or 9 decades, depending on the location in the watershed . Additionally, reductions in P phosphorus 10 loads from agricultural lands might may not be seen immediately after implementing P- following 11 implementation of phosphorus control practices because of due to current P phosphorus 12 saturation in cropland soils in areas with high ani mal densities. Reductions in nutrient loadings to 13 the bay B ay from the agricultural sector are essential to achi eve the desired water quality goals; 14 therefore, expedited implementation of effective la nd management practices agricultural will be 15 critical to reaching the 2025 goals. 16

Historical Context of Agriculture in the Chesapeake Bay Watershed 17 Since European settlement, agriculture has played a n important role in sustaining the people of 18 the Chesapeake Bay watershed. In the 1650s, the land was first bro adly cleared for timber and 19 agriculture. The land was able to support the growi ng population and in the 1700s, as agriculture 20 expanded, the first signs of environmental degradat ion were noted. By the 1750s , 20 to 30 21 percent of the forested areas were stripped for set tlement, and the shipping ports begin to fill 22 with eroded sediment. By the 1800s, plows were used widely in agriculture, beginning the 23 onslaught of permanent tillage, preventing reforest ation and encouraging soil erosion. In the first 24 half of the 1800s, the Chesapeake and Delaware cana l project encouraged even broader 25 expansion of agriculture. Half of the forests were cleared for agriculture and settlement, and the 26 first imported fertilizers (bird guano) were used f rom the Caribbean and from nitrate deposits on 27 the northern Chilean coast. 28

Agriculture in the Chesapeake Bay Watershed Today 29 Immediately following World War II, chemical fertil izer use became widespread, and as 30 suburban expansion began in the 1950s, wetlands wer e drained and filled. In the 1980s, nutrient 31 management efforts began to take hold in agricultur e, and in the 1990s, Chesapeake Bay 32 tributary strategies were put in place, setting goa ls for reductions of nutrient and sediment 33 loadings to the bay. Today Bay. Currently , for assessment purposes, the bay Bay and its tidal 34 tributaries are broken into 92 segments. The states T hese segments have been identified those 35 segments by the states as being impaired because since they do not meet water quality standards, 36 and a total maximum daily load (TMDL) will be prepa red for each of the these segments, 37 collectively adding up to the Chesapeake TMDL. The TMDL will be a calculation of the 38 maximum amount of a pollutant that the bay Bay can receive and still safely meet water quality 39 standards. 40
Approximately 25 percent of the land in the Chesapeake Bay watershed is used for agriculture. 41 The practices that some landowners and operators us e to maximize their crop yields can cause 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-5 deterioration in the quality of the bay Bay and its watershed. When farm operators improperly 1 apply fertilizers and pesticides, those these materials can flow off the land and deliver excess N, 2 P nitrogen, phosphorus , and chemicals to the bay Bay . The nutrients and bacteria in animal 3 manure, which is used for fertilizer, can seep into groundwater and run into waterways if 4 managed improperly on

- site at an AFO animal feeding operation or off

- site on cropland or 5 elsewhere. Poor tilling and irrigation practices ca n promote erosion and can lead to additional 6 sediment loads being delivered to waterbodies. At t he outflow of the tiles or along the edge of 7 drains, there is a high potential exists for loss of streamside vegetation and sediment scou ring 8 ( see See chapters 5 and 7). Those These practices can be improved, enhanced, or modified a s 9 appropriate to reduce pollutant loads from agricult ure throughout the Chesapeake Bay watershed. 10



### 1.1.4 Managing Agricultural Runoff to Reduce Nutrie nt and Sediment Loss 11

Recommended Water Pollution Control Strategy: Imple mentation of Next Generation 12 Nutrient Management Plans 13 To reach the bay Bay goals, the Chesapeake Bay Executive Order calls for implementation of the 14 next generation of tools and actions (Chesapeake Bay Program Offic e , 2010). While nutrient 15 management planning has been a part of farm operati ons since the 1980s because of due to state 16 program requirements, this document presents a desc ription of Next Generation Nutrient 17 Management Plans (NGNMPs) based on upon the state -of- or the art science and understanding 18 of the farm landscape today. To meet the bay Bay goals, NGNMPs can be implemented 19 throughout the Chesapeake Bay watershed on all row crop lands and by all anim al operations in 20 the watershed. NGNMPs will provide a strong link be tween production, nutrient management on 21 the land, and water quality. The NGNMPs described i n this document will enable producers to 22 achieve their expected yields and reduce waste of t he valuable, finite resources of nutrients and 23 sediments, while reducing the losses of the nutrien ts and sediments to surface water that 24 eventually enters the Chesapeake Bay. 25
Although agriculture is a key part of the solution to the Chesapeake Bay restoration given the 26 magnitude of loads and the relative cost-effectiven ess of practices, we must overcome there are 27 significant barriers to be overcome to reach broad-scale implementation in agriculture. Wh ile the 28 draft E xecutive Order .O. section 203 Federal Strategy notes that restoratio n of the Chesapeake 29 Bay or its watershed is not expected for many years , restoration will require a renewed 30 commitment and therefore actions taken throughout t he agricultural landscape must become 31 more strategic, coordinated, and goal-oriented to m eet the bay Bay goals (Federal Leadership 32 Committee
, 2009). 33
The most significant improvement in agricultural pr oduction needed to restore the Chesapeake 34 Bay is the need to change how excess manure nutrien ts are handled. To meet the 2025 nutrient 35 goals for the Chesapeake Bay, the agricultural community will need to broadly ad opt new 36 markets and alternative manure uses will need to be broadly adopted by the agricultura l 37 community . Doing so will not only be an essential step towar d the Chesapeake Bay goals, but it 38 will help agriculture become more sustainable and p rofitable. While the major focus of this 39 document is nutrient management, there are sections in this chapter are devoted to practices and 40 actions for AFO animal feeding operation production areas as well as sediment and erosion 41 control on row crop lands. 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-6 The most effective practices that producers can be widely implement implemented to reduce the 1 inputs of nutrients to the Chesapeake Bay focus on controlling the control of the rate, timing, 2 method and form of nutrient application. According to the best information currently available, 3 in order for the Chesapeake Bay restoration goals to be achi eved, NGNMPs to accomplish such 4 control will need to be implemented on nearly all r ow crop agriculture lands and nearly all 5 production areas of AFOs animal feeding operations in the Chesapeake Bay. This guidance 6 presents the implementation measures component of N GNMPs that would maximize reductions 7 by agriculture. 8

Achieving Multiple Benefits 9 The benefits and services provided by well

- managed agriculture in the Chesapeake Bay 10 watershed are numerous
, and include sustained crop yields; restored waterb odies for drinking 11 water, recreational, and other beneficial uses; hab itat benefits; a functioning ecosystem; reduced 12 vulnerability to invasive species; and a continued healthy and productive agricultural economy in 13 the Chesapeake Bay watershed. When effective land c over from agriculture occurs year-round, 14 those these systems can store carbon and minimize soil erosion that buries local waters and the 15 bay Bay . A healthy agricultural network in the bay Bay watershed will provide for key 16 connections across the landscape for animals and bi rds, as well as reduce the watershed’s 17 vulnerability to flooding and the effects of climat e change. 18

Readers It is recommended that readers of this chapter should guidance document also see refer to 19 Chapters 4 and 5 regarding Forestry and Riparian Bu ffers. While this chapter focuses on source 20 control and treatment options for row crop and anim al production areas in agriculture, it is 21 essential that a holistic restoration of the Chesap eake Bay watershed also achieve the benefits 22 that can be reaped when all of these systems are operating together to serve the w atershed. 23


### 1.2 Overview of the Agriculture Chapter 24 This chapter provides recommendations for the suite of practices that should be implemented in 25 the Chesapeake Bay watershed to meet the agriculture sector reduct ion goals by 2025. While 26 these recommendations are made from recent state-of -the-art literature, the chapter expands up on 27 the Management Measure for Nutrients described in t he National Management Measures to 28 Control Nonpoint Pollution from Agriculture (USEPA
, 2003). 29



### 1.2.1 Management Practices and Management Practice Systems 30 Management practices are implemented on agricultura l lands for a variety of purposes, including 31 protecting water resources, protecting terrestrial or aquatic wildlife habitat, and protecting the 32 land resource from degradation by wind, salt, and t oxic levels of metals. The primary focus of 33 this guidance is on agricultural management practic es that reduce the delivery of pollutants into 34 water resources by reducing pollutant generation or by remediating or intercepting pollutants 35 before they enter water resources. 36

NRCS maintains a National Handbook of Conservation Practices (USDA

- – NRCS
, 1977), 37 updated continuously, which details nationally acce pted management practices. Those These 38 practices are on can be viewed at the USDA-NRCS Web site at 393/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-7 http://www.nrcs.usda.gov/technical/efotg/. http:// www.nrcs.usda.gov/ technical/efotg/

. In addition 1 to the NRCS standards, many states use locally dete rmined management practices that are not 2 reflected in the NRCS handbook. Note It must be noted that while a wide variety of practices are 3 available, all require regular inspection and maint enance to ensure continued performance at 4 expected levels. Readers interested in obtaining in formation on management practices currently 5 used in their area should contact their local Soil and Water Conservation District or local USDA 6 office. Two very helpful handbooks for farmers are 60 Ways Farmers Can Protect Surface 7 Water (Hirschi et al. 1997), and 50 Ways Farmers Can Protect their Ground Water (Hirschi et 8 al. 1993). 9
Management practices are used to control a particular pollutant type from specific land uses. For 10 example, conservation tillage is used to control er osion from irrigated or non-irrigated cropland. 11 Management practices can may also provide secondary benefits by controlling othe r pollutants, 12 depending on how the pollutants are generated or tr ansported. For example, practices that which 13 reduce erosion and sediment delivery often reduce P phosphorus losses because P since 14 phosphorus is strongly adsorbed to silt and clay particles. T hus, conservation tillage not only 15 reduces erosion and , but also reduces transport of particulate P phosphorus

. 16
In some cases, a management practice can may provide environmental benefits beyond those 17 linked to water quality. For example, riparian buff ers, which reduce P phosphorus and sediment 18 delivery to water water bodies, also serve as habitat for many species of b irds and plants. 19
Sometimes, however, management practices used to co ntrol one pollutant might may 20 inadvertently increase the generation, transport, o r delivery of another pollutant ; management 21 practices should be implemented through a systems a pproach to ensure balance . Conservation 22 tillage, because it creates increased soil porosity (i.e., large pore spaces), can may increase nitrate 23 leaching through the soil, particularly when an adj ustment to the amount and timing of N nitrogen 24 application is not part of the management plan. Til e drains, used to reduce surface runoff and 25 increase soil drainage, can also have the undesirab le effect of concentrating and delivering 26 N nitrogen directly to streams (Hirschi et al. 1997). To In order to reduce the N nitrogen pollution 27 caused by tile drains, other management practices, such as nutrient management for source 28 reduction and biofilters that treat the outflow of the tile drains, might may be needed. On the 29 other hand, practices that which reduce runoff might may contribute to reduced in-stream flows, 30 which have the potential to adversely affect impact habitat. Therefore, management practices 31 should only be chosen only in the context of a holistic evaluation of both the benefits and 32 potential adverse effects impacts of the suite of practices , or management system, to be 33 implemented at a site. 34
Some management practice systems include both repet itive treatment by the same practice at 35 different places in a field as well as diversificat ion of practices to enhance all of the benefits of 36 each. An example of such a system is an animal wast e management system in which some 37 components are included to help others function. Fo r example, diversions and subsurface drains 38 might may be necessary to convey runoff and wastes to a wast e treatment lagoon for treatment. 39 While the diversions and subsurface drains might may not provide any measurable pollution 40 control of their own, they are essential to the ove rall performance of the animal waste 41 management system. Other components, such as lagoon s and waste utilization plans, are added 42 to provide repetitive treatment. 433/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-8 Note on Practice Effectiveness: The effectiveness o f any management practice is a function of a 1 variety of factors including the characteristics of the baseline condition (e.g., influent water 2 quality, soil nutrient levels, and current manageme nt practices), slope, soil type, climate, crops, 3 and weather conditions during the study. Further, t he monitoring and assessment approach used 4 in a study imparts significant limitations to interpreting the interpretation of the findings. For 5 example, inflow-outflow studies can be used to asse ss pollutant removal
, but only if the outflow 6 and inflow measurements pertain to the same parcel of water. Load and concentration reductions 7 have different meanings and utility, and it is part icularly important to have full understanding of 8 the comparison or benchmark against which the reduc tion is measured. The following summary 9 of literature findings on the effectiveness of agri cultural management practices and systems must 10 be interpreted carefully, and EPA it is strongly recommends recommended that the reader review 11 full reports be reviewed before applying the findings to any specific situat ion. 12
This chapter is divided into three separate section s regarding specific control options. 13 Generally There are generally three areas exist in agricultural production in which where
, 14 following the path of nutrients and sediment can be controll ed: sediments from their source until 15 they reach the edge of the field: 16

• Section 2: Nutrient and sediment source control and avoidance from row crop and animal 17 production areas ; 18

• Section 3: Row crop in-field controls ; and 19

• Section 4: Row crop edge

- of

- field trapping and treatment

. 20
Controlling the sources of nutrients and sediment e ntering the Chesapeake Bay through a variety 21 of approaches will minimize the pollutants availabl e throughout the agricultural operation. 22 Source control and avoidance pertains to a crop’s a bility to use the nutrients available throughout 23 the growing season, cropping cycles, feed managemen t, manure management, and chemical 24 fertilizer management. Source control approaches fo r cropland carefully evaluate the proper rate, 25 timing, method, and form of nutrient application. T his guidance separately discusses the two 26 critical topics of row crop agriculture and animal agriculture, each focusing on the specific 27 control actions that can take place when designing and implementing these distinct aspects of 28 farm operations. 29
The row crop in-field controls focus on nutrient an d sediment controls throughout the field itself. 30 In-field practices will impede the transport and/ or delivery (or both) of pollutants, either by 31 reducing water transported, and thus the amount of the pollutant transported, or by depositing 32 through deposition of the pollutant into less harmful forms into the soil or atmosphere. 33
Wetlands, drainage water management, and buffers an d setbacks are examples of important 34 edge

- of

- field or end

- of

- pipe measures to prevent nutrient loads to the Chesapeake Bay. 35 In this chapter, we present a set of implementation measures for agricultural production that are 36 intended to be implemented together as a comprehens ive management system in order to achieve 37 the overall agricultural sector goals for reducing the runoff of nutrients and sediments to the 38 Chesapeake Bay by 2025. These implementation measu res are organized into the three 39 components of source control and avoidance, in-fiel d control, and edge-of-field trapping and 40 treatment. The specific set of practices to be cho sen by an agricultural producer to achieve 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-9 pollutant reductions will necessarily be tailored a s appropriate based on a variety of factors 1 related to the landscape, agricultural operation, a nd other similar factors. 2



### 1.2.2 Implementation Measures for Agriculture in th e Chesapeake Bay 3 

### Watershed to Control Nonpoint Source Nutrient and S ediment 4 

### Pollution 5

Source Control and Avoidance 6 Row Crop Agriculture 7 The implementation measures are 8

• Base P phosphorus application on P phosphorus saturation in soils as follows: If soil 9 phosphorus ( P ) saturation levels are above 20 percent, do not app ly to row crops manure 10 or commercial fertilizer that contains P phosphorus nutrients to row crops . When soil 11 saturation level allows for application (i.e., is b elow that level), apply at an N-based rate
, 12 and determine P application rate using nutrient use efficiency (NUE) of the crop to be 13 planted. Also, instigate a soil-P monitoring plan to ensure that soil-P levels are staying 14 steady over time, and if they are increasing, adjus t P -rates; if soil-P levels increase above 15 20 percent P saturation, no longer apply P. 16

• Implement N nitrogen fertilizer use efficiency (a subset of nutrient use efficiency, or 17 NUE) to maximize the net benefit from the lowest-ne eded amount of manure or 18 commercial fertilizer N nitrogen nutrients entering the row crop system. When apply ing 19 N nitrogen , consider rate, timing, and form of manure as well

. 20

• Replace high nutrient loading crops in high-risk ar eas for water quality effects impacts 21 with sound alternatives. 22

• Retire highly erodible lands (HELs) from both cropl and and pasture, and replace them 23 with perennial native vegetation. 24

• Minimize commercial fertilizer use where manure nut rients are available. When 25 commercial fertilizer use is necessary, provide for the proper storage and calibration and 26 operation of chemical fertilizer nutrient applicati on equipment. 27

Animal Agriculture 28 The implementation measures are 29

• Manage animal feed to minimize for nutrients in exc retion that is then used as manure 30 fertilizer for all livestock. 31

• Safely and strategically apply (with properly calib rated equipment ), ),
, store , and transport 32 manure fertilizer nutrients. Liquid manure storage systems should be ( 1 a ) designed to 33 safely store the entire quantity and contents of an imal manure and wastewater produced, 34 contaminated runoff from the facility, and rainfall from the 25-year, 24-hour storm and 35 ( 2 b ) consistent with planned utilization rates or util ization practices and schedule. Dry 36 manure, such as that produced in certain poultry an d beef operations, should be stored in 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-10 production buildings, storage facilities, or otherw ise covered to prevent precipitation 1 from coming into direct contact with the manure. 2

• Exclude all livestock from streams and stream stream banks to reduce nutrient inputs, 3 stream bank erosion, sediment inputs, and improve a nimal health. 4

• Process/treat through physical, chemical, and biolo gical processes all facility wastewater 5 and animal wastes to reduce as much as practicable the volume and loss of nutrients. 6

Row Crop In- Field field Control 7 The implementation measures are 8

• Manage nutrient applications to row crop land to mi nimize nutrients available for runoff. 9 In doing so, apply manure and chemical fertilizer a pplication only during the growing 10

season only , do not apply any manure to frozen ground, inject or otherwise incorporate 11 all manure or organic fertilizer to minimize the av ailable dissolved P and volatilized N, 12 and do not apply nutrients to HELs. 13

• Control soil conditions by using soil amendments to influence P bound to soil. 14

• Use conservation tillage or continuous no-till on a ll row crops to reduce soil erosion and 15 sediment loads except on those lands that currently have no erosion or sediment loss. 16

• Use the most suitable cover crops for the site on a ll acres that have received any manure 17 or chemical fertilizer application. Cover crops sho uld be used during a non-growing 18 season (including winters ) ), or when there is bare land in a field. 19

• Minimize nutrient and soil loss from pasture land b y maintaining uniform livestock 20 distribution over the pasture, keeping livestock aw ay from riparian areas, and managing 21 stocking rates and vegetation to prevent pollutant losses through erosion and runoff. 22

• Where subsurface drainage is added to an agricultur al field, design the system to 23 minimize the discharge of N nitrogen through tile drains. 24

Row Crop Edge-of-Field Trapping and Treatment 25 The implementation measures are 26

• Integrate into farm plans fertilizer application buffers or minimum setbacks from in-field 27 ditches, intermittent streams, tributaries
, and surface waters from fertili zer application 28 into farm pl an

. 29

• Protect and restore wetlands and riparian areas fro m adverse effects and maintain 30 such this nonpoint source abatement function while protectin g other existing functions of 31 the these wetlands and riparian areas as measured by charact eristics such as vegetative 32 composition and cover, hydrology of surface water a nd ground ground water, 33 geochemistry of the substrate, and species composit ion. 34

• For both new and existing subsurface drainage syste ms, use controlled drainage, ditch 35 management, and bioreactors as necessary to minimiz e off-farm transport of nutrients. 36

• Manage all livestock production runoff and
, as well as runoff from grazing and pasture 37

areas to minimize off-farm transport of nutrients and sed iment. 383/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-11 

## 2

. Implementation Measures and practices for Source 1 

## Control and Avoidance 2


### 2.1 Row Crop Agriculture 3 In the Chesapeake Bay watershed, the overall delive ry of agriculture-based nutrients in to the 4 bay Bay needs to decrease significantly in order to protect the quality of the Chesapeake Bay. 5 Unfortunately, at present, a significant nutrient imbalance exists in the bay Bay watershed so that 6 there is an excess of P phosphorus being produced in the Bay's watershed, resulting in excess 7 P phosphorus being available for delivery to the bay Bay through surface and ground waters. 8 Nationwide, 1997 USDA estimates show that most U.S. counties (78 percent) need to move 9

manure P phosphorus from at least some animal operations to avoid P phosphorus accumulation. 10 Also Additionally , 1997 USDA estimates show that poultry operations account for two-thirds of 11 N nitrogen at farms and one-half of excess P, because of due to less land and higher P-content of 12 the manure. Dairy and hog operations also contribut e to excess on-farm P. 13
The Mid-Atlantic Water Program (MAWP), a consortium of land grant universities in the 14 Chesapeake Bay watershed, presents nutrient budgets and balances by county and state for 2007 15 (MAWP
, 2007). The nutrient budgets are defined as “a summ ary of the major nutrient inputs and 16 outputs to the cropland in a geographic region,” an d the nutrient balances are defined as “the 17 difference between nutrient inputs and outputs. ” When the nutrient balance is close to zero, 18 nutrients applied in manure and fertilizer are clos ely matched to crop use utilization . When the 19 nutrient balance is positive, nutrient inputs excee d outputs. When the nutrient balance is 20 negative, nutrient outputs exceed inputs. 21
The MAWP has developed maps, in which nutrient inpu t equals the amount of manure and 22 fertilizer nutrient available for application, and nutrient output is determined by the amount of 23 nutrient taken up by the crop, measured in the plan t biomass. The These maps do not account for 24 the level of nutrients that are already contained in the soil before prior to application of 25 additional nutrient inputs; thus
, the reader should recognize that in places where t here is a zero 26 balance, it might may seem that nutrients are being appropriately manage d . However, , however, 27 if there are high soil nutrients are available in those these areas, there could may be nutrient loss. 28 The This analysis identifies three of these hotspots in the Shenandoah River Valley in Virginia, 29 on the Eastern Shore of Maryland, and in the areas including and surrounding Lancaster County 30 in Pennsylvania (Figures 2-1 and 2-2). 313/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-12 1

2 Source: MAWP 2007

Note: The darkest color indicates counties with the highest N balances.
Figure 2-1. The map shows the N nitrogen balance for cropland in Mid

- Atlantic counties in 2007. 3 Darkest color indicates county with highest nitrogen balances. (MAWP, 2007) 43/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-13 1

2 Figure 2

- 2. The map shows the phosphorus balance for cropland in Mid-Atlantic counties in 2 007. 33/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-14 1

2
Source: MAWP 2007

Note: The darkest Darkest color indicates counties county with the highest P phosphorus balances. Figure 2-2. The map shows the P balance for croplan d in Mid-Atlantic counties in (MAWP, 2007

. 3

) 43/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-15 The following section details practices and actions that producers can implement be implemented 1 to minimize excess nutrients from entering the agri cultural production system
, to work 2 toward towards balance. 3



### 2.1.1 Nutrient Management 4 The nutrient management tools and practices currently in widespread use in the Chesapeake Bay 5 watershed for both organic (manure, sludge, and such etc. ) and inorganic (commercial fertilizer) 6 application are insufficient to prevent over-applic ation and the resulting nutrient loading to the 7 Chesapeake Bay. However, smart nutrient management planning, if broadly applied in the Bay 8 watershed, will significantly reduce nutrients avai lable as runoff into local waters and the 9 Chesapeake Bay. 10
The goal of nutrient management planning is to appl y nutrients at rates necessary to achieve 11 realistic crop yields, improve the timing of nutrie nt application, and employ appropriate tools to 12 determine the method and form of application. When manure is the source of fertilizer, both the 13 nutrient value and the rate of availability of the nutrients should must be determined, whereas 14 with commercial fertilizer that information is gene rally made available on the label. Where 15 legume crops are planted, the N nitrogen contribution of the plant itself should be determi ned and 16 credited. 17
Nutrient management planning is implemented to incr ease the efficiency with which crops use 18 applied nutrients are used by crops , thereby reducing the amount available to be trans ported to 19 both surface and ground waters. Controlling the sou rce of nutrients by practicing effective 20 nutrient management is imperative, and reducing the nutrient inputs into the agricultural system 21 will effectively minimize nutrient losses from row crops occurring at the edge-of-field by runoff 22 and by leaching from the root zone. Once N, P nitrogen, phosphorus , or other nutrients are 23 applied to the soil, their movement is largely cont rolled by the movement of soil and water and 24 must therefore be managed through other control sys tems such as erosion control and irrigation 25 water management. That This is usually achieved by developing a nutrient budge t for the crop, 26 applying nutrients at the proper time with proper m ethods, applying only the types and amounts 27 of nutrients necessary to produce a crop, and consi dering the environmental hazards of the site. 28 In cases where manure is used as a nutrient source, manure holding areas might may be needed to 29 provide capability to apply manure at optimal times

. 30
In many instances, nutrient management planning res ults in using the use of less commercial 31 fertilizer needed because of due to the availability of manure nutrients and, therefore , a reduction 32 in production costs. However the current agriculture system in the Bay watershed has a general 33 imbalance of nutrients due to excess manure generat ed annually by the combination of all 34 AFOs animal feeding operations in the watershed. Thus, for any row-crop land wher e there has 35 not been a balanced use of nutrients over a recent past, nutrient management planning should 36 incorporate options for source control—the reductio n of nutrients for input into the agricultural 37 production system— in order to reduce the possibility of excess nutrients being applied out of 38 need to reduce capacity of manure. 39
Producers, when planning nutrient Nutrient management , planning should consider all aspects of 40 the rate, timing, method and form of nutrients, consistently in a consistent and coordinated 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-16 using manner based upon the host of data that can be available through effective use of nutrient 1 use tools. Nutrient management plans typically focu s mainly on N nitrogen and P phosphorus , the 2 nutrients of greatest concern for water quality, an d it is important to consider all sources of these 3 nutrients as input into the agricultural system. Th e major sources of nutrients include the 4 following : 5

• Commercial fertilizers 6

• Manures, sludges, and other organic materials 7

• Crop residues and legumes in rotation 8

• Irrigation water 9

• Soil reserves 10
Smart nutrient management planning can significantl y reduce costs. The total cost of a nutrient 11 management system are those costs associated with m anure nutrient application, plus the 12 disposal of alternative use cost, or penalty cost, for manure that cannot be applied within a 13 reasonable local transport area, less the savings i ncurred by reduced commercial fertilizer. 14

Because N nitrogen and P phosphorus behave very differently, basic understanding of ho w 15 N nitrogen and P phosphorus are cycled in the soil-crop system is an important foundation for 16 effective nutrient management. The National Management Measures to Control Nonpoint 17 Pollution from Agriculture (USEPA
, 2003) is an excellent source reference describing the 18 technical details of each of the these nutrient sources and cycles in agriculture. 19

N Ni trogen is continually cycled among plants, soil organisms , soil organic matter, water, and the 20 atmosphere in a complex series of biochemical trans formations. Some N nitrogen forms are 21 highly mobile, while others are not. At any given time, most of the N nitr ogen in the soil is held 22 in soil organic matter (decaying plant and animal t issue) and the soil humus. Mineralization 23 processes slowly transform the N nitrogen in soil organic matter by microbial decomposition to 24 ammonium ions (NH 4 +), releasing them into the soil where they can be strongly adsorbed and 25 relatively immobile. Plants can use the ammonium, h owever, and it can may be moved with 26 sediment or suspended matter. Nitrification by soil microorganisms transforms ammonium ions 27 (either mineralized from soil organic matter or add ed in fertilizer) to nitrite (NO 2 -) and then 28 quickly to nitrate (NO 3 -), which is easily taken up by plant roots. Nitrat e, the form of N nitrogen 29 most often associated with water quality problems, is soluble and mobile in water. 30 Immobilization includes processes by which ammonium and nitrate io ns are converted to 31 organic-N, through uptake by plants or microorganis ms, and bound in the soil. Denitrification 32 converts nitrate into nitrite (NO 2 ) and then to nitrous oxide (N 2 O) and gaseous N nit rogen through 33 microbial action in an anaerobic environment. 34

An N A nitrogen molecule can may pass through the this cycle many times in the same field. The 35 processes in the N nitrogen cycle can occur simultaneously and are controlled by soil organisms, 36 temperature, and availability of oxygen and carbon in the soil. The balance among the these 37 processes determines how much N nitrogen is available for plant growth and how much can may 38 be lost to ground ground water, surface water, or the atmosphere. 39

P Phosphorus lacks an atmospheric connection (although it can b e transported via airborne soil 40 particles) and is much less subject to biological t ransformation, rendering the P p hosphorus cycle 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-17 considerably simpler. Most of the P p hosphorus in soil occurs as a mixture of mineral and organic 1 materials. A large amount of P p hosphorus (50–75 percent) is held in soil organic matter
, which 2 is slowly broken down by soil microorganisms. Some of the organic P p hosphorus is released into 3 soil solution as phosphate that is immediately avai lable to plants. The phosphate released by 4 decomposition or added in fertilizers is strongly a dsorbed to soil particles and are rapidly 5 immobilized in forms that are unavailable to plants . The equilibrium level of dissolved 6 P p hosphorus in the soil solution is controlled by the chemical environment of the soil (e.g.
, pH, 7 oxidation-reduction, iron concentration) and by the P p hosphorus content of the soil. 8
Throughout the Chesapeake Bay watershed, those these processes are constantly occurring 9 throughout agricultural lands. To In order to effectively plan, design, and implement controls, i t 10 is imperative to understand these basic scientific cycles. 11

Phosphorus 12 Implementation Measure: Base P application on P saturation in soils as fol lows: If soil phosphorus (P) saturation levels are above 20 perce nt, do not apply to row crops manure or commercial fertilizer that contains P nutrients. Wh en soil saturation level allows for application (i.e., is below that level), apply at a N-based rat e and determine P application rate using nutrient use efficiency (NUE) of the crop to be planted. Als o, instigate a soil-P monitoring plan to ensure that soil-P levels are staying steady over time, an d if they are increasing, adjust P -rates; if soil- P levels increase above 20 percent P saturation, no l onger apply P. Implementation Measure: Base phosphorus application on phosphorus saturatio n in soils 13 as follows: If soil P saturation levels are above 2 0 percent, do not apply manure or 14 commercial fertilizer that contains phosphorus nutr ie nts to row crops. When soil 15 saturation level allows for application (i.e., is b elow that level), apply at an N

- based rate, 16 and determine P application rate using nutrient use efficiency of the crop to be planted. 17
In the Chesapeake Bay watershed, where animal manur e is a dominant and available source of 18 fertilizer, there is an overabundance of P phosphorus as fertilizer exists as described above. 19
Because P attaches to the soil particles and thus b uilds up in the soil, to protect water quality
, P 20 fertilizer application is dependent up on the existing soil-P levels. P does not pose an 21 environmental risk when it is insoluble
, which occurs when it is sorbed to soils. For there to be 22 an environmental risk to exist that is associated with P the transport of P to surface waters, P 23 must be in a form that can be released to water. Th us, the P saturation rate does not measure 24 directly the risk for P loss in runoff; the P satur ation rate indicates the amount of P that is 25 desorbed and moved into solution (Kovzelove et al

. . , 2010). Butler and Coale (2005) describe 26 how the P release from soil when in contact with wa ter increases exponentially once the P 27 saturation level is between 20

– – 30 percent. 28

EPA recommends It is recommended that P fertilizer not be applied to soils that are in or above 29 the range where P desorption and loss as runoff can occur. Thus, it is important for the nutrient 30 management plan to address consider the slope and movement patterns for water as runof f in a 31 field, because P saturation does not dictate the pr obability of P in runoff to move to a ditch or 32 local waterbody. 333/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-18 Tools There are tools that can be used to plan for the applicable rate, timing , form
, and method 1 of P fertilizer application. Understanding P saturation levels throughout the fi eld in soils is 2 necessary to ensure that the farmer is not applying P that is above the level needed for the crop 3 and dually affecting water quality. P saturation le vel calculations can These tools have varying 4 degrees of technical needs and can all be implemented with the assistance of NRCS, extensi on 5 agents, TSPs
, or other private industry consultants and research ers. 6
Beck et al. (2004) have calculated for three major physiographic regions of Virginia the degree 7 of P saturation as a function of Mehlich 1 extracta ble P for soils. That calculation provides a 8 useful model that can be adopted throughout the Che sapeake Bay watershed. 9

Nitrogen 10 Implementation Measure: Implement N fertilizer use efficiency (a subset of NUE) to maximize the net benefit from the lowest-needed amount of ma nure or commercial fertilizer N nutrients entering the row crop system. When applying N, cons ider rate, timing, and form of manure as well. Implementation Measure: Implement nitrogen fertilizer use efficiency (a sub set of nutrient 11 use efficie ncy, or NUE) to maximize the net benefit from the l owest

- needed amount of 12 manure or commercial fertilizer nitrogen nutrients entering the row crop system. When 13 applying nitrogen, consider rate, timing, and form of manure as well. 14
Nutrient Use Efficiency (NUE), also known as precis ion agriculture or decision agriculture, 15 relies on developing the N nitrogen application rate on the basis of based upon in-field variability 16 measured in real time. Practicing NUE to control th e amount of N input into the system in row 17 crop agriculture calibrates the yield potential to N needed by a plant , in order to ensure that N 18 loss is minimized through reductions in leaching, s urface flow, ammonia volatilization, 19 nitrification and denitrification, and soil erosion . NUE is effective in reducing N loss when both 20 the crop

- removal efficiency (the efficiency of the crop to t ake in all N nitrogen made available to 21 it ) ), works in tandem with the increase in residual nutr ients available from the soil during the 22 time the crop is growing. 23

Producers’ Currently, there is limited use of N nitrogen use efficiency tools is limited in 24 reducing to reduce over-applied N nitrogen from leaving the production field and entering int o 25 local waterways. N Nitrogen use efficiency is critical because higher use effi ciency reduces the 26 level of excess N nitrogen available to create potential environmental proble ms. 27
NUE includes two main components: 28

• Crop removal efficiency, or the removal of nutrient in a harvested crop as a percent of 29 nutrient applied to the crop (Mosier et al

. , 2004) , and 30

• The increase in residual nutrients available to the crop from the soil Ladha et al . (
, 2005)

. 31
When developing the N nitrogen application rate of a nutrient management plan for any row crop, 32 NUE guides the farmer or planner through a series o f steps to determine the rate. The first step is 33 to commit to realistic production goals based on so und data to replace typical N application rates 34 with levels based up on specific plant need requirements. The second ste p is to employ 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-19 precision/decision agriculture systems and tools to efficiently apply N though improved 1 materials, timing, placement
, and use utilization . A variety of in-field tests can be used to adjust 2 inputs in order to meet the optimum yield of the plant in a manner where N loss to the 3 environment is minimized. 4
Maryland and Delaware have determined a suite of pr actices that make up a decision agriculture 5 program, and other states in the Chesapeake Bay watershed are actively considering similar 6 approaches; there is a broad range of effective tools that can be used where applicable. The 7 These tools have varying degrees of technical needs and c an all be implemented with the 8 assistance of NRCS, extension agents, TSPs
, or other private industry consultants and 9 researchers. These include , but are not limited to the following decision agriculture tools 10 (additional tools and references are can be found in Appendix 2.): 11

• Stalk nitrate tests for field corn production is one of the best metho ds to estimate N 12 application rate for subsequent years. The test is done at the end-of-season
, and provides 13 field specific data to know if the N available for crop uptake was deficient, marginal, 14 optimal, or in excess for the plant to produce the optimum yield. The results of the this 15 test can be used to improve the NUE practice, and t he NUE effectiveness is enhanced 16 when the results are shared among localized area fa rmers with comparable row crop 17 production conditions

. (Blackmer and Mallarino
, 1996)

. 18

• Crop testing is a broader approach for a wider diversity of cro ps than the stalk nitrate 19 test , but can include that tool for field corn productio n. Crop testing is used generally to 20 detect the relative plant available N by sight with a leaf color chart or chlorophyll meter, 21 measuring plant available soil N with the Pre-Sided ress Nitrate Test (PSNT ) ), or 22 employing real time chlorophyll measurement for var iable rate application in the field. 23

• Fertilizer prescription rate maps can be a very useful tool in NUE; they these are 24 developed using strategic soil testing and global positioning system ( GPS ) crop yield 25 monitoring data. Soil tests are conducted throughou t a field using based on soil property 26 characteristics and GPS crop yield data mapping to measure the soil nutrient supplying 27 capacity, to chart the field variability of immobil ized N, to determine realistic crop 28 production levels , and to help determine and to assist in determining the subsequent 29 season’s season's appropriate nutrient prescriptive application rate s. 30

• To maintain existing soil fertility levels, crop nutrient removal can be used to measure 31 the difference between the application rate and the plant uptake rate. Simple charts can be 32 devised to employ this tool, yet there are specific software programs are available to ease 33 the calculations. 34

• Aerial imagery and strip trials are individual tools, but when coupled at the end of a 35 season, can provide an effective means to understan d the spatial variability of a field 36 remotely. This can also lend an understanding of fi eld areas where there are signs of 37 planter or applicator skips, diseased or pest

- damaged areas, weed infestations and other 38 non-uniform areas
, which can decrease the amount of plant available N required to meet 39 crop needs. 40

• Protein maps can be developed from real

- time sensing of plant and grain characteristics. 41 Plant and grain analysis allows the farmer to evaluate the effectiveness of previous 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-20 nutrient management tools and practices to manage f ertilizer application throughout the 1 field. 2

• Nutrient source integration is used generally with organic fertilizer (manure) , as a part 3 of developing a manure management plan. This tool p rovides multiple benefits and is 4 used to determine subsequent season’s season's manure needs and can simplify manure 5 application records. 6

• A tool being developed for the future is environmental risk assessment . This considers 7 the location of the field and its potential to impa ir local or far-field areas using based upon 8 known transport factors. 9



### 2.1.2 Alternative Crops 10
Implementation Measure: Replace high nutrient loading crops in high-risk a reas for water quality effects with sound alternatives.
Implementation Measure : Replace high nutrient loading crops in high

- risk areas for water 11 quality impacts with sound alternatives

. 12
High-risk areas exist in places where there is inte nse animal agriculture because of , due to the 13 resulting imbalance in nutrients. High-nutrient-loa ding crops, such as corn and soybean, should 14 be replaced with alternatives in environmentally se nsitive areas such as areas in close proximity 15 to local waters. 16
Local agricultural contacts such as extension agent s, conservation district staff, and consultants 17 can provide the best assistance in choosing alterna tive crops while meeting production goals. In 18 Maryland, the document Alternative Agriculture in Maryland: A Guide to Eva luate Farm-Based 19 Enterprises (Musser
, et al. 1999) provides a workbook with 78 separate decision worksheets. 20 The USDA National Agricultural Library document Alternative Crops & Enterprises for Small 21 Farm Diversification (Gold and Thompson
, 2009) provides a broad range of information on 22 alternative crops. 23



### 2.1.3 Land Retirement 24
Implementation Measure: Retire highly erodible lands (HELs) from both crop land and pasture, and replace them with perennial native vegetation.
Implementation Measure : Retire hig hly erodible lands (HELs) from both cropland and 25 pasture , and replace them with perennial native vegetation

. 26
The methodology used in implementing the Farm Bill Conservation Reserve Program has 27 encouraged the retirement of highly erodible lands (HELs) from both cropland and pasture and 28 replacement with perennial vegetation. 29

When the these lands are retired through the federal program, a s et of environmental benefit 30 indicators are considered: 313/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-21 • Water quality benefits from reduced erosion, runoff , and leaching 1

• Wildlife habitat benefits resulting from covers on contract acreage 2

• On-farm benefits from reduced erosion 3

• Benefits that will likely endure 4

• Air quality benefits from reduced wind erosion 5

• Cost 6

Those These indicators can be used to assess environmentally s ensitive areas as well as USDA7 identified HELs to determine where they are in the Chesapeake Bay watershed. Nutrients should 8 not be applied to HELs, even if the these lands are in continued row crop production. When l ands 9 are retired from production, regardless of their se nsitivity to runoff and erosion, their associated 10 nutrient inputs become null. 11
When HELs follow parallel to stream channels, producers should employ the recommendations 12 from Chapters 5 and 7 (Riparian and Hydromodificati on)) should be employed as the perennial 13 vegetation. 14



### 2.1.4 Chemical Fertilizer Application, Storage, and Transport 15
Implementation Measure: Minimize commercial fertilizer use where manure nu trients are available. When commercial fertilizer use is necess ary, provide for the proper storage and calibration and operation of chemical fertilizer nu trient application equipment.
Implementation Measure: Minimize commercial fertilizer use where manure nut rients are 16 available. When commercial fertilizer use is necessary, provid e for the proper storage and 17 calibration and operation of chemical fertilizer nu trient application equipmen t. 18
Inorganic, commercial fertilizers represent the lar gest single source of N nitrogen and 19 P phosphorus applied to most cropland in the U nited States .S . In the Chesapeake Bay watershed, 20 commercial fertilizers are used when manure is not readily available. Major commercial fertilizer 21 N nitrogen sources include anhydrous ammonia, urea, ammonium nitrate, and ammonium sulfate. 22 Major P phosphorus fertilizer sources include monoammonium phosphate, diammonium 23 phosphate, triple superphosphate, ammonium phosphat e sulfate, and liquids. Descriptions of 24 common fertilizer materials are given in Table 2

- - 1. 25

Table 2-1. Common commercial fertilizer minerals 26 Analysis (%) Common name chemical formula N P 2 O 5 K 2 O
N Analysis (%) Common Name Chemical Formula N P2O5 K2O Nitrogen materials Ammonium nitrate NH 4 NO 3 34 % 0 % 0 % Ammonium sulfate (NH 4 ) 2 SO 4 21 % 0 % 0 % Ammonium nitrate-urea NH 4 NO 3 +(NH 2 ) 2 CO 32 % 0 % 0 %3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-22 Anhydrous ammonia NH 3 82 % 0 % 0 % Aqua ammonia NH 4 OH 20 % 0 % 0 % Urea (NH 2 ) 2 CO 46 % 0 % 0 % Phosphate materials
Superphosphate Ca(H 2 PO 4 ) 2 0 % 20 %–

- 46 % 0 %
Ammoniated superphosphate Ca(NH 4 H 2 PO 4 ) 2 5 % 40 0 % Monoammonium phosphate NH 4 H2PO 4 13 % 52 % 0 % Diammonium phosphate (NH 4 ) 2 HPO 4 18 % 46 % 0 % Urea-ammonium phosphate (NH 2 ) 2 CO+(NH 4 ) 2 HPO 4 28 % 28 % 0 %

Potassium materials Muriate of potash KCl 0 % 0 % 60 % Monopotassium phosphate KH 2 PO 4 0 % 50 % 40 % Potassium hydroxide KOH 0 % 0 % 70 % Potassium nitrate KNO 3 13 % 0 % 45 % Potassium sulfate K 2 SO 4 0 % 0 % 50 % Note: Adapted from Source: Pennsylvania State University (

. 1997 ) and

. The Penn State Agronomy Guide, 1997

- 1998, University Park, PA. Cornell Cooperative Extension (

. 1997 )

. 1997 Cornell Recommendations for Integrated Fiel d Crop Management. Resource Center, Cornell University, Ithaca, NY.

1 Commercial fertilizers offer the advantage of allow ing exact formulation and delivery of nutrient 2 quantities specifically tailored to the site, crop, and time of application in concentrated, readily 3 available forms. The use of any particular material or blend is governed by the characteristics of 4 the formulation (such as volatilization potential a nd availability rate), suitability for the particul ar 5 crop, crop needs, existing soil test levels, econom ics, application timing and equipment, and 6 handling preferences of the producer. 7
However, because of due to the nutrient imbalance from the amount of livestock manure 8 produced in the Chesapeake Bay watershed, EPA recommends it is recommended that producers 9 minimize commercial fertilizer use of commercial fertilizer be minimized where manure 10 nutrients are available to be used. EPA It is also recommends recommended that provisions be in 11 place for storing the storage of fertilizer, as well as properly calibrating the proper calibration and 12 operating operation of commercial fertilizer application equipment. 13

14


### 2.2 Animal Agriculture 15

In the Chesapeake Bay watershed, because of the intensity of animal a griculture and manure 16 generation, enhancing nutrient source control is im perative in the production area. All 17 AFOs animal feeding operations should provide the capacity to store (1) all liqui d manure 18 generated and contents of animal manure and wastewa ter produced, (2) contaminated runoff 19 from the facility and rainfall events in the geogra phic area, (3) dry manure, such as that produced 203/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-23 at poultry operations, in production buildings or s torage facilities or otherwise with a cover. All 1 AFO personnel animal feeding operations should also ensure there is no runoff of pollutants is 2 occurring from the production area or discharged discharges through conveyances to local waters, 3 including any precipitation-related water that come s into contact with the animals, animal by4 products, litter
, or feed. Regarding the The location of manure storage systems , producers should 5 consider proximity to water water bodies, floodplains, HELs
, and other environmentally sensitive 6

areas. 7 Strategies for source control associated with anima l agriculture focus on containing and treating 8 feed, manure, and facility wastewater and preventin g their movement to surface waters. Four 9 general principles can help control sources of nutr ients and other pollutants from animal 10 agriculture: animal feed management, manure storage and transport, treatment or processing of 11 wastes, and management of grazing livestock. 12



### 2.2.1 Animal Feed Management 13 Important feeding strategies for livestock producti on focus on adjustment of feed additives, 14 formulations, or feeding methods to reduce the nutr ient content or change the form of nutrient 15 excreted in manure. Decreasing the P phosphorus and N nitrogen content of manure through diet 16 modification is a powerful, cost-effective approach to reducing the nutrient balance and nutrient 17 losses from livestock farms (Knowlton et al. 2004; Maguire et al. 2007; Swink et al. 2009). 18 Reduction of P phosphorus and N nitrogen overfeeding, use of feed additives to enhance diet ary 19 P phosphorus and N nitrogen utilization, and development of grains in which a high proportion of 20 the P is available (high-available P grains) have a ll been shown to decrease fecal P phosphorus 21 and N nitrogen excretion without impairing animal performance (Ma guire et al. 2005). 22

Implementation Measure: Manage animal feed to minimize for nutrients in ex cretion that is then used as manure fertilizer for all livestock.
Implementation Measure : Manage animal feed to minimize for nutrients in excretion that 23 is then used as manure fertilizer for all livestock

. 24

Practice Effectiveness 25 Arriaga et al. (2009) estimated that dietary manipu lation in Spain could decrease dairy herd 26 N nitrogen excretion by 11 percent per hectare, whereas P phosphorus would be decreased by 17 27 percent. On two New York NY dairy farms, Cerosaletti et al. (2004) reported that fecal P 28 concentrations decreased 33 percent following dieta ry adjustments; milk production was not 29 adversely affected. In a modeling study of the same New York NY farms, precision feed 30 management reduced the P imbalance on each farm and reduced the soluble P lost to the 31 environment by 18 percent (Ghebremichael et al. 2007). Ebeling et al. (2002) applied dairy 32 manure from two dietary P levels to corn land in Wi sconsin and reported that at equivalent 33 manure rates, dissolved P concentration in runoff f rom the high P diet manure was 10 times 34 higher (2.84 versus vs. 0.30 mg/ L) than the low P diet manure, and four times highe r (1.18 35

versus vs. 0.30 mg/L) when applied at equivalent P rates. 36
In a review, Graham et al. (2003) reported that including the inclusion of xylanase or phytase in 37 poultry feeds can reduce manure volume by up to 14 percent and N and P outputs by up to 13 383/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-24 percent and 70 percent, respectively. A review by P owers and Angel (2008) reported that for 1 each 1 percent reduction in dietary crude protein, estimated NH 3 losses are decreased by 10 2 percent; 20–40 percent reductions in NH 3 emissions from poultry houses have been reported. For 3 P, under commercial conditions, broiler litter P wa s decreased by 30 percent when diet P was 4 decreased by 10 percent. In North Carolina, Leytem et al. (2008) reported that inclusion of 5 phytase in poultry diets at the expense of inorgani c P or reductions in dietary available P 6 decreased litter total phosphorus (TP) P by 28 to 43 percent. Litter water-soluble P decreas ed by 7 up to 73 percent with an increasing dietary Ca/avai lable P ratio, irrespective of phylase addition. 8 Nahm (2009) reported that phytase addition to simpl e gastric animal diets in South Korea can 9 decrease the litter water-soluble P concentration b y 30–35 percent. In Arkansas, Smith et al. 10 (2004) showed that phytase and high-available P cor n diets reduced litter-dissolved P content in 11 broiler litter by 10 and 35 percent, respectively, compared with the normal diet (789 mg P/kg). 12 P Phosphorus concentrations in runoff water were highest from p lots receiving poultry litter from 13 the normal diet, whereas plots receiving poultry li tter from phytase and high

- available P corn 14 diets had reduced P concentrations. 15
In Canada, Emiola et al. (2009) showed that complete removal of inorg anic P from growing pig 16 diets coupled with phytase supplementation improves digestibility and retention of P and N, thus 17 reducing manure P excretion without any negative ef fect on pig performance. In another 18 Canadian study, Grandhi (2001) reported that replac ing inorganic P with phytase and lowering 19 the dietary protein level while supplementing amino acids in swine diets can decrease the 20 excretion of P up to 44 percent and N up to 28 perc ent in manure with no adverse effect on 21 performance of pigs. In a Danish study, replacing i norganic phosphates with phytase in pig feed 22 reduced the concentration of P in slurry by 35 perc ent (Sommer et al. 2008). In Europe, Aarnink 23 and Verstegen (2007) found that a combination of lo wering crude protein intake and increasing 24 fermentable carbohydrates, and other modifications to feeding strategies could reduce ammonia 25 emission from growing-finishing pigs by 70 percent. 26

Table 2-2. Summary of reported practice effects res ulting from changes in animal feeding 27 strategies

. 28

Location Study

type Practice Practice effects Source Spain Farms Dairy feed

formulation 11% reduction in N excretion;

17% reduction in P excretion Arriaga et al. 2009

NY Farm Dairy dietary

management 33% reduction in manure P concentration Cerosaletti et al. 2004
NY Model Dairy precision

feeding 18% reduction in soluble P lost from farm Ghebremichael et al. 2007
WI Field Dairy dietary

management 75% reduction in dissolved P in runoff from

land applied manure a manure 1 Ebeling et al. 2002

Many Review Phytase in

poultry feed 14% reduction in manure volume; 13%

reduction in litter N, 70% reduction in litter P Graham et al. 2003

Many Review Poultry feed

formulation 10% reduction in NH3 losses per 1%

decrease in dietary crude protein; 30% reduction in litter P with 10% reduction in dietary P Powers and Angel 20083/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-25 Location Study

type Practice Practice effects Source NC Animal

trials Phytase in

poultry feed 28–43% decrease in litter T total P;

Up to 73% reduction in litter water-soluble P b P 2 Leytem et al. 2008

S Korea Review Phytase in

poultry feed 30–35% reduction in litter water-soluble P Nahm 2009

AR Farm/p

lot Phytase and

high available P corn in poultry feed 10% reduction in litter dissolved P with

phytase; 35% reduction with high available P corn c corn 3 Smith et al. 2004

Canada Animal

trials Swine diet Removal of inorganic P from diet plus phytase supplementation improved digestibility and retention of P and N, reduced manure P excretion without negative effects on growth Emiola et al. 2009

Canada Animal

trials Swine diet 44% reduction in P excretion, 28% reduction in N excretion from replacing inorganic P with phytase and lowering dietary protein Grandhi 2001

Denmark Farm Phytase in

swine diet 35% reduction in P in slurry Sommer et al. 2008

Europe Review Swine feeding

strategies d strat egies 4 70% reduction in ammonia emissions from

growing-finishing operations Aarnink and Verstegen 2007

Notes:

a. Footnotes:

1 high High-P diet manure and low-P diet manure applied at equivalent P rates b. 2 with With increasing Ca/available P in feed, irrespectiv e of phytase
c. 3 study Study also reported that P concentrations in plot r unoff were reduced where litter from modified diets was applied d. 4 Feeding changes included lowering crude protein in take, increasing fermentable carbohydrates, and add ition of acidifying salts 1 Possible case study outlining plain sect colla boration 2 Watson Run (Lancaster Co) PA Agricultural assessmen t pilot project. 3 24 farms involved, 19 agreed to allow us to test pr ivate wells. Mostly Plain Sect. 4
Public health concerns can drive clean water effort s on nutrient control beyond where they 5 could otherwise go. Lancaster is the highest manure nutrient concentrat ion in the Bay 6 watershed. 7 Drinking Water Sampling Results 8 Sampled 19 out of 24 farm wells 9
9 out of 19 contained Total coliform bacteria 10
6 out of 19 contained E. coli bacteria 11
16 out of 19 ex ceeded the MCL for nitrate 123/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-26 

### 2.2.2 Manure Storage, and Transport 1
Implementation Measure: Safely and strategically apply (with properly cali brated equipment), store, and transport manure fertilizer nutrients. L iquid manure storage systems should be (1) designed to safely store the entire quantity and co ntents of animal manure and wastewater produced, contaminated runoff from the facility, an d rainfall from the 25-year, 24-hour storm and (2) consistent with planned utilization rates o r utilization practices and schedule. Dry manure, such as that produced in certain poultry an d beef operations, should be stored in production buildings, storage facilities, or otherw ise covered to prevent precipitation from coming into direct contact with the manure.

The manure and other wastes generated by livestock production should be contained and 2 management should prevent runoff losses from the fa cility. Key measures and some component 3 practices include the following: 4
Implementation Measure : Safely and strategically apply (wit h properly calibrated 5 equipment), store and transport manure fertilizer nutrients. Liquid manure storage 6 systems should be (a) designed to safely store the entire quantity and contents of animal 7 manure and wastewater produced, contaminated runoff from the facility, and rainfall from 8 the 25

- year, 24

- hour storm and (b) consistent with planned utilizat ion rates or utilization 9 practices and schedule. Dry manure, such as that pr oduced in certain poultry and beef 10 operations, should be stored in production buildin gs, storage facilities, or otherwise 11 covered to prevent precipitation from coming into d irect contact with the manure

. 12 The manure and other wastes generated by livestock production must be contained and 13 management must prevent runoff losses from the faci li ty. Key measures and some component 14 practices include: 15

• Ensure that the farm has sufficient storage for all manure. 16

– Waste storage facility (NRCS Practice Code 313): A waste impoundment made by 17 constructing an embankment
, and/or excavating a pit or dugout, or by fabricating a 18 structure. 19

– Waste treatment lagoon (NRCS Practice Code 359) : An impoundment made by 20 excavation or earth fill for biological treatment o f animal or other agricultural wastes. 21

• Ensure that manure and litter are stockpiled safely

. 22

– Set clean-out schedules that ensure no poultry litt er stockpiling during times of the 23 year with the greatest environmental losses
, (e.g., winter). 24

– Do not stockpile manure without covers and liners. 25

– Divert clean water away from waste storage areas. 26

– Diversion (NRCS Practice Code 362) : A channel constructed across the slope 27 with a supporting ridge on the lower side. 28

– Roof runoff management (NRCS Practice Code 558) : A facility for controlling 29 and disposing of runoff water from roofs. 30

• Ensure that any recipient of manure has planned eff ectively to meet, at a minimum, the 31 same performance goals as those of the sourced manu re. 323/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-27 – Areas receiving manure should be managed in accorda nce with meeting the goals for 1 erosion and sediment control, irrigation, and grazi ng management applicable, 2 including practices such as crop and grazing manage ment practices to minimize 3 movement of nutrient and organic materials applied, and buffers or other practices to 4 trap, store, and process materials that might move during precipitation eve nts. 5

– Waste utilization (NRCS Practice Code 633) : Using agricultural wastes or other 6 wastes on land in an environmentally acceptable man ner while maintaining or 7 improving soil and plant resources. 8

There is little recent literature quantifying the e ffectiveness of the practices in this category. 9 Some basic effectiveness information has been cited in National Management Measures to 10 Control Nonpoint Pollution from Agriculture (USEPA
, 2003). 11



### 2.2.3 Livestock Exclusion from Streams 12
Implementation Measure: Exclude all livestock from streams and streambanks to reduce nutrient inputs, stream bank erosion, sediment inpu ts, and improve animal health.
Implementation measure : Exclude all livestock from streams and stream banks to reduce 13 nutrient inputs, stream bank erosion , sedime nt inputs, and improve animal health

. 14
Grazing livestock should be excluded from streams a nd riparian areas to reduce direct nutrient 15 and pathogen inputs, prevent streambank damage and resulting sediment inputs, and improve 16 animal health. Fencing is the most reliable way to protect streams and riparian areas from the 17 effects impacts of livestock. Fencing can be woven wire or electri c; cost-share programs 18 might may require permanent fencing, rather than temporary o r movable fence. Management 19 intensive or rotational grazing could may , however, involve using the use of movable fences to 20 create temporary paddocks to direct livestock away from a water course. If complete fencing is 21 not possible, the most sensitive streambank areas s hould be fenced, while providing limited areas 22 for access to drinking water for grazing animals. S ome trials have documented success in 23 keeping livestock out of streams without continuous fencing by providing drinking water and/ or 24 shade or both away from the stream to encourage livestock to cong regate away from riparian 25

areas. 26

Practice Effectiveness 27 Livestock exclusion fencing 28

Line
, et al. (2000) documented 33, 78, 76, and 82 percen t reductions in weekly nitrate + nitrite, 29 total Kjeldahl nitrogen (TKN), total phosphorus ( TP ) , and sediment lends, respectively, resulting 30 from fencing dairy cows from a 10

- to 16

- m wide riparian corridor along a small North Caroli na 31 stream. In the same system, Line (2003) showed that fecal coliform and enterococci levels 32 decreased 65.9 percent and 57.0 percent, respective ly
, after livestock exclusion. 33
In Vermont streams draining dairy pastures, Meals ( 2002) reported 20–50 percent reductions in 34 nutrient and suspended solids loads and 40–60 perce nt reductions in fecal bacteria counts 35 following livestock exclusion and riparian restorat ion with bioengineering techniques. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-28 James
, et al. (2007) estimated 32 percent reduction of in -stream deposition of fecal P phosphorus 1 by grazing dairy cattle in New York following lives tock exclusion under the CREP. 2
In central Pennsylvania, Carline and Walsh (2007) r eported that following riparian treatments, 3 consisting of fencing, 3- to 4-m buffer strips, str eam bank stabilization, and rock-lined stream 4 crossings, stream bank vegetation increased from 50 percent or less to 100 percent in formerly 5 grazed riparian buffers, suspended sediments during base flow and storm flow decreased 47

– - 87 6 percent in both streams, and macroinvertebrate dens ities increased in two treated streams. 7 However, Agouridis
, et al. (2005) reported that incorporation of an al ternate water source and/ or 8 fenced riparian area along a central Kentucky strea m did not significantly alter stream cross9 sectional area over treatment reaches. The authors suggested that riparian recovery within the 10 exclosures from pretreatment grazing practices might may require decades, or greater 11 intervention (i.e., stream restoration), before a s ubstantial reduction in streambank erosion is 12 noted. 13
Alternative water supply 14 In Georgia, Franklin
, et al. (2009) found that when the temperature and humidity index (THI) 15 ranged between 62 and 72, providing cattle with wat er troughs outside of riparian zones tended 16 to decrease time cattle spent in riparian zones by 63 percent. The study suggests that water 17 troughs placed away from unfenced streams may impro ve water quality by reducing the amount 18 of time cattle spend in riparian zones. 19
However, Line (2003) reported that levels of most m easured physical parameters and bacteria 20 were not significantly different following the inst allation of alternate water supply in a North 21 Carolina pasture. 22

Table 2-3

. Summary of reported practice effects resulting fro m livestock exclusion

. 23 Location Study type Practice Practice effects Source NC Small

watershed Fencing dairy

cattle Load reductions: 33% NO2+NO3-N,

78% TKN, 76% TP, and 82% sediment Line
, et al. 2000

NC Small

watershed Fencing dairy

cattle Reductions: 66% fecal coliform, 57%

enterococci Line 2003

VT Small

watersheds Fencing dairy

cattle; riparian restoration Load reductions: 20–50% TP, TKN,

TSS Reductions: 40–60% fecal coliform, fecal strep., and E. coli Meals 2002

NY Stream Fencing dairy cattle a cattle 1 32% reduction in deposition of fecal P

in stream James
, et al. 2007

PA Small

watersheds Fencing, buffer

strips, stream bank stabilization, rock-lined stream crossings Streambank vegetation increase from

< 50% to 100%; 47–87% reduction in SS concentrations; increase in macroinvertebrate densities Carline and Walsh 2007

GA Stream Off-stream water supply 63% decrease time cattle spent in

riparian zones Franklin
, et al. 2009 NC Stream Off-stream water supply No significant changes in physical

water quality parameters or bacteria Line 20033/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-29 Location Study type Practice Practice effects Source
counts

Note:

a. Footnotes:

1 Livestock exclusion under Conservation Reserve Enh ancement Program (CREP) 1



### 2.2.4 Wastewater and Animal Wastes 2
Implementation Measure: Process/treat through physical, chemical, and biol ogical processes all facility wastewater and animal wastes to reduce as much as practicable the volume and loss of nutrients.
Implementation measure : Process/treat thro ugh physical, chemical, and biological 3 processes all facility wastewater and animal wastes to reduce as much as practicable the 4 volume and loss of nutrients

. 5
Manure and wastewater stored on farms has a signifi cant pollution potential even after wastes are 6 collected and stored appropriately. Researchers hav e recommended a variety of practices to 7 manage the effects impacts of animal wastes, focusing on treating treatment of waste to change 8 its physical, chemical, or biological properties ; , remove potential pollutants ; , or improve 9 handling characteristics (Bicudo and Goyal 2003; Ri tter et al. 2003; Martinez et al. 2009). 10
Such practices These include the following : 11

• Waste treatment and processing —treating manure or farm wastewater to separate 12 liquids and solids, immobilize pollutants, or remov e nutrients from the wastestream 13

• waste stream; 14

• Digestion —processing animal wastes to capture biogas for use as fuel, reducing bulk of 15 remaining residuals for further management ; 16

• Composting —composting of animal wastes, possibly combined wit h other green wastes, 17 to reduce bulk, stabilize nutrient forms, and facil itate export and land application of 18 animal wastes ; 19

• Wetland treatment —to remove nutrients by plant uptake and promotion of 20 denitrification ; 21

• Other biological treatments —treatment systems using microorganisms, algae, or other 22 plants to break down wastes and absorb nutrients ; 23

• Air quality management —practices to reduce or capture airborne pollutants like 24 ammonia or fine particulates from animal housing 25

Practice Effectiveness 26 Waste treatment and processing—manure and wastewate r amendment 27 Amending poultry litter with alum [Al 3 (SO 4 ) 2 -14H 2 O] has received considerable attention as a 28 method of economically reducing ammonia volatilizat ion in the poultry house and soluble P 293/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-30 phosphorus in runoff waters. In South Korea, Do et al. (2005) reported that application of 1 aluminum chloride (AlCl 3 -6H 2 O) to litter lowered atmospheric ammonia concentrat ions at 42 2 days by 97.2 percent % , whereas ferrous sulfate (FeSO 4 -7H 2 O) lowered it by 91 percent %

. 3 Ammonia concentrations were reduced by 86, 79, 76, and 69 percent % by alum, alum + CaCO 3 , 4 aluminum chloride + CaCO 3 , and potassium permanganate (KMnO 4 ), respectively, when 5 compared with a control at 42 days. The addition of 6.25 percent % zeolite or 2.5 percent % alum 6 to dairy slurry in Maryland reduced ammonia emissio ns by nearly 50 and 60 percent %
, 7 respectively. Alum treatment retained ammonia by re ducing the slurry pH to 5 or less. In 8 contrast, zeolite, (a cation exchange medium) adsor bed ammonium and reduced dissolved 9 ammonia gas (Lefcourt and Meisinger 2001). 10
In Arkansas, Moore et al. (1998 and 2000) reported that reductions in litter pH in alum-treated 11 broiler litter reduced NH 3 volatilization by 97 percent % , which led to reductions in atmospheric 12 NH 3 in the alum-treated houses. Broilers grown on alum -treated litter were significantly heavier 13 than controls (1.73 kg versus vs. 1.66 kg). Soluble reactive P (SRP) concentrations in runoff from 14 pastures fertilized with alum-treated litter were 7 5 percent lower than those from normal litter. 15 Also in Arkansas, Smith et al. (2001) found that al um and aluminum chloride amendment to 16 swine manure reduced SRP concentrations in runoff b y 84 percent and were not statistically 17 different from SRP concentrations in runoff from un fertilized control plots. Smith et al. (2004) 18 reported that the addition of alum to the various p oultry litters reduced P runoff from pastures 19 where the litter was applied by 52 to 69 percent; t he greatest reduction occurred when alum was 20 used in conjunction with dietary modification with high available phosphorus ( HAP ) corn and 21 phytase. 22
In Pennsylvania, Dou et al. (2003) reported reducti ons of soluble P in dairy, swine, and broiler 23 manures of 80 to 99 percent at treatment rates of 1 00 to 250 g alum/kg manure dry matter. 24 Fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60 percent at a rate of 25 400 g/kg for all three manures. Flue gas desulfuriz ation by-product (FGD) reduced soluble P by 26 nearly 80 percent when added to swine manure and br oiler litter at 150 and 250 g/kg. 27
In laboratory studies, alum reduced ortho-P in dair y wastewater 93

– - 99 percent at rates less than 28 3 g alum/L. Ortho-P was reduced to 1 mg P/L or less by a combination of alum and 29 polyacrylamide (PAM) treatment (Jones and Brown 2000). 30
Oh et al. (2005) reported that alum and polymer add ition improved the efficacy of mechanical 31 separation of dairy manure. When compared to the co ntrol, waste amended with alum and 32 polymer had 82 percent less TP in the press liquor, which indicates that P was partitioned into 33 the press cake. The combined alum/polymer treatment also resulted in a 36 percent reduction in 34 total solids ( TS ) and a 71 percent reduction in chemical oxygen dema nd (COD) in the press 35 liquor when compared to the control. 36
Codling et al. (2000) recommended substituting Al-r ich drinking water treatment residuals 37 (WTR) for alum for reducing water-soluble P in poultry li tter. In Ohio, Dayton and Basta (2005) 38 reported that blending WTR water treatment residuals to manure at 250 g/kg or reduced CaCl 2 – 39 extractable P by > 75 percent. In a Vermont study, Meals et al. (2007) found that additions of 40 alum-based WTR water treatment residuals to liquid dairy manure could reduce manure soluble P 41 concentrations up to 79 percent and T to tal P concentrations by up to 50 percent. 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-31 In Idaho, Entry and Sojka (2000) reported that trea tment of cattle and swine manure with 1 combinations of PAM polyacrylamide , Al(SO4) 3 , and CaO treatments reduced fecal bacteria 2 counts by 10- to 1 000 1 ,000-fold in water flowing downstream of treated ma nure application 3 sites, compared to the untreated manure control. 4
In Taiwan, Cheng (2001) was able to reduce COD leve ls in swine wastewater by 54 percent to 5 190 mg/L using coagulants such as aluminum chloride , ferric chloride, calcium hydroxide, and 6 polyaluminate chloride (PAC)

. 7

Table 2-4. Summary of reported practice effects res ulting from waste amendment

. 8 Location Study type Practice Practice effects Source Korea Poultry

house Poultry litter

amendments Atmospheric ammonia concentration

reductions: 97% (Aluminum chloride), 91% (Ferrous sulfate), 86% (alum), 79% (alum+CaCO 3 ), 76% (aluminum chloride+CaCO 3 ), 69% (KMnO 4 ) Do et al. 2005

MD Dairy farm Dairy slurry amendments 50% ammonia emissions reduction

(zeolite), 60% ammonia emissions reduction (alum) Lefcourt and Meisinger 2001

AR Poultry

houses Alum

amendment 97% ammonia volatilization; 75% reduction

in soluble P in runoff from pastures receiving treated litter Moore et al. 1998 and 2000

AR Field Alum and aluminum chloride treated poultry litter 52-69% reduction in P concentration in

runoff from pastures where treated litter applied a applied 1 Smith et al. 2004

AR Plots Alum and aluminum chloride treated swine manure 84% reduction in soluble P concentration

in runoff from plots receiving treated manure; P concentration not significantly different from un-manured control plots Smith et al. 2001

PA Laboratory Dairy, swine, broiler manure amendments Manure soluble P reductions: 80-99%

(alum), 50-60% (fly ash), 80% (flue gas desulfurization byproduct Dou et al. 2003

Unknown Laboratory Dairy wastewater amendment 93 -99% reduction in ortho-P with alum

treatment; ortho-P reduced to <1 mg P/L by alum and PAM polyacrylamide combined Jones and Brown 2000

Unknown Laboratory Dairy manure amendment Liquid from separated manure amended

with alum and polymer had 82% less TP, 36% less TS, and 71% lower COD than untreated manure Oh et al. 2005

OH Laboratory Dairy manure amendment Amending dairy manure with WTR water

treatment residuals reduced CaCl 2 - extractable P >75% Dayton and Basta 2005

VT Laboratory Dairy manure amendment Amending dairy manure with alum-based

WTR water treatment residuals reduced manure soluble P up to 79%, T total P up to 50% Meals et al. 20073/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-32 Location Study type Practice Practice effects Source ID Field Cattle, swine
manure amendment Amending manure with PAM, alum, and

CaO treatments reduced fecal bacteria 90–>99% in runoff from application sites compared to untreated manure control Entry and Sojka 2000

Taiwan Laboratory Swine wastewater amendment Amending swine wastewater with alum,

ferric chloride, calcium hydroxide, and polyaluminate chloride reduced COD by 54% Cheng 2001

Note:

a. Footnotes:

1 Greatest P reductions when alum used in conjunctio n with dietary modification

Waste treatment and processing—waste separation 1 Note that waste separation does not treat wastes in the sense of removing or inactivating 2 pollutants; rather, the process of separation produ ces a separate liquid and solid waste stream that 3 may facilitate handling, transport, and further use of waste components. 4
An inclined stationary screen separator removed 61 percent of the TS total solids , 63 percent of 5 the volatile solids, 49 percent of the TKN, 52 perc ent of the organic–N, and 53 percent of the 6 T total P from South Carolina dairy manure in a flush syste m; the complete manure treatment 7 system consisting of the screen separator, separato r, a two–chambered settling basin, and a 8 lagoon removed 93 percent of the TS, 96 percent of the VS, 74 percent of the TKN, 91 percent of 9 the organic–N, and 86 percent of the T total P (Chastain et al. 2001). 10
In Wisconsin, Converse and Karthikeyan (2004) repor ted that long-term settling of flushed dairy 11 manure will remove 75 to 80 percent of TP from raw flushed manure or separator effluent and 12 concentrate it in the bottom 25 percent of the volu me. Cantrell et al. (2008) reported that 13 geotextile filtration of liquid dairy manure in Sou th Carolina reduced volume to less than 1 14 percent of total influent volume concentrated the s olids and nutrients in the dewatered material 15 16 to 21 times greater than the influent, and retai ned 38 percent of TS, 26 percent of TAN, and 16 45 percent of TP. In South Carolina, Garcia et al. (2009) used the natural flocculant chitosan to 17 improve the performance of screen separation effici encies for flushed dairy manure to > 95 18 percent for total suspended sediment ( TSS ) , > 73 percent for TKN, and > 54 percent for TP. 19
Although screening alone was not effective for sepa rating swine waste in a North Carolina study, 20 Vanotti et al. (2002) found that adding PAM before screening increased separation efficiencies to 21 95 percent TSS and volatile suspended solids ( VSS ) , 92 percent organic P, 85 percent organic N, 22 69 percent COD, and 59 percent BOD 5 ; the N-P nutrient ratio was improved from 4.79 to 12.11, 23 resulting in a more balanced effluent for fertilizi ng crops. In a subsequent study, Vanotti et al. 24 (2005) reported that a combined flocculation and fi ltration treatment system removed 97 percent 25 of TSS and VSS, 85 percent of BOD, 83 percent of CO D, 61 percent TKN, and 72 percent of TP 26 from flushed swine manure. 27

Table 2-5. Summary of reported practice effects res ulting from waste separation

. 28 Location Study type Practice Practice effects Source3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-33 Location Study type Practice Practice effects Source SC Farm Inclined stationary
screen separator For flush-system dairy manure, separator

removed 61% of TS, 63% of the volatile solids, 49% of the TKN, 52% of the organic– N, and 53% of the T total P Chastain et al. 2001

SC Farm Separator + settling basin + lagoon For flush-system dairy manure, full system

removed 93% of TS, 96% of the volatile solids, 74% of the TKN, 91% of the organic– N, and 86% of the TP total P Chastain et al. 2001

WI Laboratory Long-term settling 75-80% of T total P removed from raw flushed

dairy manure, concentrated in 25% of original volume Converse and Karthikeyan 2004 SC Farm Geotextile separation For liquid dairy manure, reduced volume to

<1% of influent volume and retained 38% of TS, 26% of TN, and 45% of TP Cantrell et al. 2008

SC Farm Flocculation + separation Use of natural flocculant chitosan improved

performance of screen separation efficiencies for flushed dairy manure to >95% for TSS, >73% for TKN, and >54% for TP Garcia et al. 2009

NC Farm PAM + screening For swine waste, addition of PAM before

screening increased separation efficiencies to 95% TSS and VSS, 92% organic P, 85% organic N, 69% COD, and 59% BOD 5 ; Vanotti et al. 2002

NC Farm Flocculation + filtration System removed 97% of TSS and VSS, 85%

of BOD, 83% of COD, 61% TKN, and 72% of TP from flushed swine manure Vanotti et al. 2005

Waste treatment and processing—lagoon treatment 1 Waste treatment processes typically leave a residua l material after producing a cleaner effluent; 2 thus
, the reductions cited in the literature generally r efer to the treated effluent compared to the 3 original waste. In all cases, the residual should must be managed properly to prevent pollution 4 impacts. 5 Aerobic lagoon treatment of swine waste in Nova Sco tia accomplished removals of 59–71 6 percent TSS, 59–73 percent VSS, 42–60 percent TKN, and 42–51 percent NH 4 -N (Trias et al. 7 2004). In France, combined aerobic/anoxic treatment of swine manure wastewater achieved 86 8 percent reduction in TSS, 90 percent reduction in T N and COD (Prado et al. 2009); 50 percent of 9 soluble P was biologically removed by an intermitte nt aerobic/anoxic sequence. 10
In Korea, Ra et al. (1998) reported that a two-stag e sequencing batch reactor system achieved 11 removal efficiencies of 98 percent TOC, 100 percent NH 4 -N, 98 percent TKN, 97 percent 12 ortho Ortho -P, 98 percent T total P, 97 percent suspended solids (SS) and 97 percent volatile 13 suspended solids ( VSS )

. 143/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-34 Table 2-6. Summary of reported practice effects res ulting from lagoon treatment

. 1

Location Study

type Practice Practice effects Source Nova Scotia Farm Aerobic lagoon For swine waste, removals of 59-71% TSS, 59– 73% VSS, 42–60% TKN, and 42–51% NH 4 -N Trias et al. 2004 France Farm Aerobic/anoxic

lagoons For swine manure wastewater, achieved

86% TSS reduction, 90% TN and COD reduction; 50% of soluble P was biologically removed by an intermittent aerobic/anoxic sequence. Prado et al. 2009

Korea Farm Two-stage

sequencing batch reactor Removal efficiencies of 98% TOC, 100% NH 4 -N,

98% TKN, 97% ortho Ortho -P, 98% T to tal P, 97% suspended solids, and 97% volatile suspended solids from swine waste Ra et al. 1998

NC Farm Solids separation

+ biological N and P removal For swine waste treatment, removal of 73-98%

TSS, 40-76% of TS, 77-100% of BOD 5 , 85-98% of TKN and NH 4 -N, 38-95% of TP, and 37-99% of Zn and Cu. Vanotti and Szogi 2008

NC Farm Solids separation

+ biological N and P removal (2 nd generation) For swine waste treatment, removal of 98%

TSS, 97% NH 4 -N, 95% TP, 99% Zn and Cu, 99.9% odors, and 99.99% pathogens Vanotti and Szogi 2009

Vanotti and Szogi (2008) tested a new swine waste t reatment system combining liquid-solids 2 separation with biological N and P removal in North Carolina and reported removal of 73

– - 98 3 percent TSS, 40–76 percent of TS, 77

– - 100 percent of BOD 5 , 85

– - 98 percent of TKN and NH 4 - 4 N, 38

– - 95 percent of TP, and 37

– - 99 percent of Zn and Cu. A second-generation versio n of the 5 system removed 98 percent TSS, 97 percent NH 4 -N, 95 percent TP, 99 percent Zn and Cu, 99.9 6 percent odors, and 99.99 percent pathogens (Vanotti et al. 2009). 7
Waste treatment and processing—other treatment 8 Masse et al. (2007) reviewed the most recent litera ture on membrane filtration for manure 9 concentration and treatment and found studies of ul trafiltration (UF) of manure that reported up 10 to 100 percent removal of coliform and SS, 87 perce nt P reduction, but no effect on soluble COD 11 from ultrafiltration (0.01 μ m) and lower efficiency from microfiltration (0.2 μ m), e.g., 75 percent 12 SS removal. 13
In Ireland, Healy et al. (2004) tested recirculatin g sand filters for treatment of dairy wastewater 14 and reported TN reduction of 27 to 41 percent; TN r eduction increased to 83 percent when sand 15 filter effluent was recirculated through an anoxic zone. A subsequent study (Healy et al. 2007) 16 reported consistent COD and TSS removals of greater than > 99 percent, and an 86 percent 17 reduction in TN. 18
Lee and Song (2006) reported average 81 percent COD , 92 percent SS, 68 percent TN, and 95 19 percent TP removal using ozone to treat livestock w astewater through a dissolved air flotation 20 system in Korea. Separation, collection, and treatm ent of swine waste with an ammonia recovery 21 process using a metal ion treated resin bed achieve d > 90 percent reduction in ammonia content 223/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-35 in North Carolina (Loeffler and van Kempen 2003). R emoval of up to 90 percent of P from 1 swine waste treated by chemical precipitation with struvite and hydroxyapatite was reported in 2 South Korea (Choi et al. 2008). 3

Table 2-7. Summary of reported practice effects res ulting from other wastewater treatment

. 4

Location Study

type Practice Practice effects Source Numerous Review Membrane

filtration Ultrafiltration ( UF) ( 0.01 μ m) of manure: up to

100% removal of coliform and SS, 87% P reduction, no effect on soluble COD; lower efficiency from microfiltration (0.2 μ m: 75% SS removal. Masse et al. 2007

Ireland Farm Recirculating

sand filter For dairy wastewater, reported TN reduction of

27 to 41%; TN reduction increased to 83% when sand filter effluent was recirculated through an anoxic zone Healy et al. 2004

Ireland Farm Recirculating

sand filter For dairy wastewater, COD and TSS removals of

> greater than > 99%, and an 86% reduction in TN Healy et al. 2007

Korea Farm Ozone dissolved

air flotation system Average removals of 81% COD, 92% SS, 68%

TN, and 95% TP removal from livestock wastewater Lee and Song 2006

NC Farm Separation +

ammonia recovery a recover y 1 Achieved > 90% reduction in ammonia content in

swine waste Loeffler and van Kempen 2003

Korea Farm Chemical

precipitation b pre cipitation 2 Up to 90% removal Removal of P from swine

waste Choi et al. 2008

Notes:

a. Footnotes:

1 Ammonia recovery using a metal ion treated resin b ed b. Struvite 2 struvite and hydroxyapatite

Digestion 5 Anaerobic digestion of manure can offer substantial benefits, both economic and intangible, to 6 animal feeding operators and surrounding communitie s, such as renewable energy generation,; 7 reduction in bulk and improvement of handling chara cteristics,; production of stable, liquid 8 fertilizer and high-quality solid soil amendment; r eduction in odors
, ; reduction of greenhouse 9 gasses (GHGs);
, ; and reduction in ground and surface water contamin ations (Demirer and Chen
, 10 2005; Cantrell et al. 2008; Garrison and Richard 20 05). There is ample literature [link to lit 11 review?] concerning digester performance and yield, but not all studies report performance 12 relevant to water quality concerns. It should be no ted that digestion does not generally remove 13 nutrients from the original waste material
, and the residuals from digestion require further 14 management. 15
Costa et al. (2007) evaluated the efficiency of the anaerobic digestion in reducing the organic 16 load of swine waste. Results showed an average redu ction of COD of 58 percent. 173/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-36 In Turkey, Gungor-Demirci and Demirer (2004) invest igated the potential biogas generation 1 from anaerobic digestion of broiler and cattle manu re. The efficiency of total COD removal was 2 32

– - 43 percent and 40

– - 50 percent for initial COD concentrations of 12,000 and 53,500 mg / L, 3 respectively. The biogas yields observed for initia l COD concentrations of 12,000 and 53,500 4 mg/ L l were 180

– - 270 and 223

– - 368 mL ml gas/g COD added, respectively. 5
A thermochemical conversion process applied to the treatment of swine manure for oil 6 production in Illinois achieved a 75 percent reduct ion in COD (He et al. 2000). Lansing et al. 7 (2008a) reported 84 percent reduction in COD and a 78 percent increase in dissolved NH 4 -N 8 concentration in a study of seven low-cost digester s in Costa Rica. In a companion study of very 9 small farms, Lansing et al. (2008b) reported reduct ions in COD of 86 percent for dairy digester 10 and 92 percent for a swine digester. 11
Thermophilic aerobic digestion reduced volatile sol ids by 28

– - 54 percent in Ireland, while 12 producing Class A biosolids suitable for land appli cation (Layden et al. 2007). Anaerobic 13 digestion of poultry feces in Nigeria achieved > 99 percent reductions in E. coli bacteria counts 14 compared to an undigested, but equal-aged control ( Yongabi et al. 2009). 15
In China, adding additional undigested swine wastewater to digested wastewater in a sequencing 16 batch reactor process significantly improved with COD removal to > 80 percent and NH 4 -N 17 removal up to 99 percent (Deng et al. 2005). The ef fluent COD concentration was in the range of 18 250 mg/L to 350 mg/L and effluent NH 4 -N concentration was < 10 m/L. A pilot

- scale 19 sequencing batch reactor built to treat swine waste in Australia achieved NH 4 -N and odor 20 reductions of > 99 percent as well as 79 percent removal of COD and a 49 percent reduction of 21 PO 4 -P on a mass balance basis because of due to struvite formation within the reactor (Edgerton 22 et al. 2000). 23
In China, enhancement of a traditional sequencing b atch reactor for swine waste with two-step 24 feeding and low-intensity aeration at laboratory sc ale yielded reductions of 94 percent TN, 99 25 percent TP, and 99.9 percent BOD 5 , possibly reflecting the activity of denitrifying P phosphorus

26 accumulating organisms (Lue et al. 2008; Lu et al. 2009). 27

Table 2-8. Summary of reported practice effects res ulting from manure digestion

. 28

Location Study

type Practice Practice effects Source Unknown Farm Anaerobic digestion Average reduction of COD of 58%. Costa et al. 2007 Turkey Pilot Anaerobic digestion For digestion of broiler and cattle manure,

COD removal was 32-43% and 40-50% for initial COD concentrations of 12,000 and 53,500 mg/L, respectively. The biogas yields observed for initial COD concentrations of 12,000 and 53,500 mg/L were 180-270 and 223-368 mL ml gas/g COD added, respectively GungorDemirci and Demirer 2004

IL Pilot Thermochemical conversion 75% reduction in COD of swine manure He et al. 2000 Costa Rica Farms Anaerobic digestion 84% reduction of COD; 78% increase in NH 4 -

N Lansing et al. 2008a Costa Farms Anaerobic 86% reductions of COD for dairy digester Lansing et al.3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-37 Location Study

type Practice Practice effects Source Rica digestion 92% reductions of COD for a swine digester 2008b
Ireland Farm Thermophilic aerobic digestion 28–54% reduction in volatile solids a solids 1 Layden et al. 2007 Nigeria Farm Anaerobic digestion > 99% reductions in E. coli b coli 2 Yongabi et

al. 2009 China Farm Sequencing batch reactor Adding additional undigested swine

wastewater to digested wastewater in a sequencing batch reactor process significantly improved with COD removal to > 80% and NH 4 -N removal up to 99% Deng et al. 2005

Australia Pilot Sequencing batch reactor For swine waste, > 99% NH 4 -N and odor

reductions, 79% removal of COD, and a 49% reduction of PO 4 -P on a mass balance basis c basis 3 Edgerton et al. 2000

China Laboratory Enhanced sequencing batch reactor d reactor 4 Reductions of 94% TN, 99% TP, and 99.9%

BOD 5 , possibly from due to growth of denitrifying P phosphorus -accumulating organisms Lue et al. 2008; Lu et al. 2009

Notes:

a. Footnotes:

1 Produced Class A biosolids suitable for direct lan d application b. 2 Compared to an undigested, but equal-aged control
c. 3 Due to struvite formation within the reactor d. 4 Addition of two-step feeding and low-intensity aer ation to traditional SBR

Composting 1 Like digestion, composting of animal manure can red uce bulk, kill microorganisms, improve 2 handling, and provide a value-added product (Brodie et al. 2000). While significant quantities of 3 N can may be lost through volatilization in the composting p rocess (consider air quality issues), 4 composting has little net effect on the T total P content of the material. 5
In Texas, ( Bekele et al. ( 2006) documented a 19–23 percent decrease in solubl e P in streams 6 draining areas where significant quantities of manu re had been composted and removed from the 7 watershed. 8
Gibbs et al. (2002) measured nutrient losses from a erobic composting of cattle manure in the 9 UK. Total mass loss ranged from 23 percent for an u nturned static composting to 67 percent of 10 the initial mass for the indoor composting turned t hree times. N Nitrogen losses from the manure 11 heaps ranged from 8 to 68 percent of the initial to tal manure N content. Gaseous N losses, 12 primarily as NH 3 , accounted for between 7 and 67 percent of the ini tial manure N content. 13
In beef feedlot manure composting in Alberta, Canad a, Larney and Hao (2007) reported that 14 exposure of manure to temperatures > 55 ° o C for a period of 15 d ays appears to be an effective 15 method of inactivating both Giardia cysts and Cryptosporidium oocysts in feedlot manure. The 16 authors report mean carbon C and N concentrations in eight feedlot manure compos ts: total 17 carbon TC 228 g/kg, TN 16.0 g/kg, soluble carbon C 11.3 g/kg, soluble N 1.6 g/kg. 183/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-38 Das et al. (2002) reported that co-composting of ch icken hatchery waste and poultry litter was 1 effective in eliminating 99.99 percent of E. coli bacteria in Georgia. Koenig et al. (2005) 2 reported that aluminum sulfate and process controls such as moisture content, carbon source and 3 particle size have the potential to reduce NH 3 loss from poultry manure composted inside high4 rise layer structures. 53/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-39 Table 2-9. Summary of reported practice effects res ulting from manure 1

Location Study

type Practice Practice effects Source TX Watershed Composting + export 19%–23% decrease in soluble P in streams

draining areas where significant quantities of manure had been composted and removed from the watershed Bekele et al. 2006

UK Farm Aerobic composting 23% mass loss for an unturned static

composting; 67% mass loss for the indoor composting turned 3 times Compost piles lost 8–68% of initial TN total N ; gaseous N losses, primarily as NH 3 , accounted for 7%–67% of the initial manure N Gibbs et al. 2002

Canada Farm Aerobic composting Exposure to temperatures >55 ° o C for 15 d

inactivated Giardia

cysts and Cryptosporidium oocysts in beef feedlot manure Larney and Hao 2007

GA Farm Co-composting Co-composting of chicken hatchery waste and poultry litter was effective in eliminating 99.99% of E. coli bacteria Das et al. 2002

2

Wetland treatment 3 Wastewater from dairy and swine operations has been successfully treated in constructed 4 wetlands (Hunt and Poach 2001). Plants are an integ ral part of wetlands. Cattails and bulrushes 5 are commonly used in constructed wetlands for nutri ent uptake, surface area, and oxygen 6 transport to sediment. Improved oxidation and nitri fication can may also be obtained by using the 7 use of the open water of marsh-pond-marsh designed wetland s. High levels of N nitrogen 8 removal by denitrification have been reported from constructed wetlands, especially when the 9 wastewater is was partially nitrified (Hunt et al. 2009). Solids rem oval before prior to wetland 10 treatment is essential for long-term functionality. 11
A constructed wetland to treat incoming barnyard ru noff in Ireland retained > 60 percent % of the 12 P load delivered to the wetland (Dunne et al. 2004) . A subsequent study (Dunne et al. 2005) 13 reported that P retention by the wetland varied wit h season (5–84 percent) with lowest retention 14 occurring in winter. 15
In a review of 12 constructed wetlands treating liv estock wastewater on the south coast of 16 Ireland, Harrington and McInnes (2009) reported tha t over an 8- eight year period
, mean 17 reduction of total and soluble P exceeded 95 percen t and the mean removal of ammonium-N 18 exceeded 98 percent. 19
Mustafa et al. (2009) reported removal efficiencies of 98 percent BOD, 95 percent COD, 94 20 percent SS, 99 percent ammonia N, 74 percent NO 3 -N, and 92 percent soluble P in dairy 21 wastewater treatment through a constructed wetland system in Ireland. 22
Lee et al. (2004) reported that average reduction e fficiencies in subsurface flow constructed 23 wetlands in Taiwan were : SS 96–99 percent, COD 77–84 percent, T total P 47–59 percent, and 243/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-40 T total N 10–24 percent. While physical mechanisms were dom inant in removing pollutants, the 1 contributions of microbial mechanisms increased wit h the duration of wetland use, achieving 48 2 percent of COD removed and 16 percent of TN removed in the last phase. Water hyacinth made 3 only a minimal contribution to the removal of nutri ents. 4

In Kansas
, Mankin and Ikenberry (2004) evaluated a constructe d wetland without vegetation as a 5 sequencing batch reactor . Using 3 ; using three -week batch periods without plants, overall mass 6 removal averaged 54 percent for COD, 58 percent for TSS, 90 percent for TN, 72 percent for 7 NH 4 , -54 percent for NO3, 38 percent for TP, and -8 pe rcent for PO 4 . 8
Prantner et al. (2001) reported that a UK wetland s ystem treating liquid swine manure after soil 9 infiltration removed 94 percent of the NH 3 -N and NH 4 -N, 95 percent of the NO 3 -N, and 84 10 percent of the TP. 11

total P. 12
Flow of dairy wastewater through the wetland system in Maryland resulted in significant 13 reductions in concentrations of all analytes except nitrate/nitrite (Schaafsma et al. 2000). Relative 14 to initial concentrations, T total N was reduced 98 percent, ammonia 56 percent, T total P 96 15 percent, ortho-P 84 percent, SS suspended solids 96 percent, and BOD 97 percent. Nitrate/nitrite 16 increased by 82 percent, although mean concentratio ns were much lower than concentrations of 17 ammonia or TN 18
total nitrogen 19
In Nova Scotia, Smith et al. (2006) reported load r eductions from 62 to 99 percent for BOD, 20 TSS, TP, and NH 3 -N in wetlands treating agricultural wastewater. Al so in Nova Scotia, Wood et 21 al. (2008) reported mass reductions of 54 percent f or T total P and 53 percent soluble P over 22 4 four

years in a surface flow constructed wetland milkho use wash water and liquid manure. In 23 Vermont, a subsurface flow constructed wetland with a slag filter removed 75 percent of P mass 24 from dairy barnyard runoff and milk parlor waste (W eber et al. 2007). 25

Table 2-10. Summary of reported practice effects re sulting from wetland treatment 26

Location Study

type Practice Practice effects Source Ireland Farm Constructed

wetland Retained > 60% of the P load delivered in

barnyard runoff; P retention by the wetland varied with season (5 %–

- 84%) with lowest retention occurring in winter Dunne et al. 2004, 2005

Ireland Review Constructed

wetland 8- year yr mean reduction of total and soluble P >

95% and the mean removal of ammonium-N > 98%. Harrington and McInnes 2009 Ireland Farm Constructed

wetland Removal efficiencies of 98% BOD, 95% COD,

94% SS, 99% ammonia N, 74% NO 3 -N, and 92% soluble P in dairy wastewater treatment Mustafa et al. 2009

Taiwan Review Constructed wetlands (subsurface flow) Average reduction efficiencies in subsurface

flow constructed wetlands in Taiwan were : SS 96-99%, COD 77-84%, T total P 47-59%, and TN total N 10-24% a 1

. Lee et al. 20043/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-41 Location Study

type Practice Practice effects Source KS Wetland Constructed

wetland without vegetation Mass removal averaged 54% COD, 58% TSS,

90% TN, 72% NH 4 , -54% NO3, 38% TP, and -8% PO 4 Mankin and Ikenberry 2004
UK Farm Constructed

wetland Treating liquid swine manure after soil infiltratio n

removed 94% of NH 3 -N and NH 4 -N, 95% of NO 3 -N, and 84% of T total P. Prantner et al. 2001

MD Farm Constructed

wetland Treating dairy wastewater T total N reduced

98%, ammonia 56%, T total P 96%, ortho-P 84%, SS suspended solids 96%, and BOD 97%; Nitrate/nitrite increased 82% Schaafsma et al. 2000

Nova Scotia Farm Constructed wetland Load reductions from 62–99% for BOD, TSS,

TP, and NH 3 -N treating agricultural wastewater Smith et al. 2006 Nova Scotia Farm Constructed wetland Load reductions of 54% T total P and 53%

soluble P treating milkhouse wash water and liquid manure Wood et al. 2008

VT Farm Subsurface flow constructed wetland with slag filter Removed 75% of P mass from dairy barnyard

runoff and milk parlor waste Weber et al. 2007

Note:

a. Footnotes:

1 Physical mechanisms were dominant in removing poll utants; the contributions of microbial mechanisms i ncreased with the duration of wetland use. Water hyacinth ma de only a minimal contribution to the removal of nu trients.
1 Other biological treatment 2 A multiple-pond system (APS) treating dairy milking parlour effluent in New Zeal and produced 3 effluent with 50–60 percent less BOD, TSS, TKN and ammonia-N than equivalently sized two

- - 4 pond systems with medians of 43, 87, 61
, and 39 mg/L, respectively. T Total P was reduced by 5 70 70 percent to 19 mg/L. E

. scherichia coli were reduced in the APS by two orders of magnitude 6 to 918 MPN/100 mL ml (Bolan et al. 2009). 7 In Morocco, El Hafiane et al. (2003) reported avera ged removals of 70 percent for N and 40 40 8 percent for P in a high-rate algal pond treating wa stewater. Water hyacinth ponds were reported 9 to achieve ~50 percent removal of applied organic lo ads (COD, BOD, TN, and TP) from swine 10 waste in Brazil (Costa et al. 2000). 11
In Scotland, an algal-based bioreactor achieved sus tained nutrient removal efficiencies (up to 12 99 99 percent and 86 percent for NH 4 -N and PO 4 -P
, respectively) from swine wastewater while 13 total COD was removed up to 75 percent (Gonzalez et al. 2008). Lu et al. (2008) augmented a 14 wetland treating duck waste in China with water hya cinth and reported removal of 64 percent of 15 COD, 22 22 percent TN total N , and 23 percent T total P loads. The hyacinth was harvested and 16 recycled as duck feed. 17
Anaerobically digested dairy manure effluent was tr eated with algal turf scrubber raceways in 18 Maryland (Mulbry et al. 2008). Removal rates of 70

– - 90 percent of input N and P were achieved 193/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-42 at loading rates below 1 g TN, 0.15 g TP /m 2 /d; N and P removal rates decreased to 50

– - 80 1 percent at higher loading rates. 2
An entrapped mixed microbial cells (EMMC) process was used to investigate the simultaneous 3 removal of carbon and N nitrogen from dilute swine wastewater in Hawaii (Yang, Chen et al. 4 2003). COD removal efficiencies were 84 percent and T total P removal efficiencies of 98 5 percent were achieved. 6

Table 2-11. Summary of reported practice effects re sulting from other biological treatment

. 7

Location Study

type Practice Practice effects Source Numerous Review Membrane filtration Ultrafiltration (UF) (0.01 μ m) of manure: up to

100% removal of coliform and SS, 87% P reduction, no effect on soluble COD; lower efficiency from microfiltration (0.2 μ m: 75% SS removal. Masse et al. 2007

Ireland Farm Recirculating sand filter For dairy wastewater, reported TN reduction of

27 to 41%; TN reduction increased to 83% when sand filter effluent was recirculated through an anoxic zone Healy et al. 2004

Ireland Farm Recirculating sand filter For dairy wastewater, COD and TSS removals of

> greater than > 99%, and an 86% reduction in TN Healy et al. 2007

Korea Farm Ozone dissolved air flotation system Average removals of 81% COD, 92% SS, 68%

TN, and 95% TP removal from livestock wastewater Lee and Song 2006

NC Farm Separation + ammonia recovery a recove ry 1 Achieved > 90% reduction in ammonia content in

swine waste Loeffler and van Kempen 2003

Korea Farm Chemical precipitation b pre cipitation 2 Up to 90% removal Removal of P from swine

waste Choi et al. 2008

Notes:

a. Footnotes:

1 Ammonia recovery using a metal ion treated resin b ed b. Struvite 2 struvite and hydroxyapatite
8 Air quality 9 Ammonia, dust, and odors associated with animal agr iculture—especially on large facilities— 10 can be important local air pollutants. For example, Melse and Timmerman (2009) reported that N 11 emissions in exhaust air from pig houses in the Net herlands can represent as much as 25 percent 12 of the T total N excretion by the animals. Airborne ammonia can al so become a significant water 13 pollutant when deposited in local waterbodies. Indo or air quality can affect animal health as well, 14 especially at large poultry facilities. Animal prod uction facilities can be important producers of 15 GHSs greenhouse gasses (van der Meer 2008). 163/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-43 Ullman et al. (2004) reviewed abatement technologie s available to reduce atmospheric emissions 1 from animal production facilities and summarized th e following: 2

• Scrubbers have been shown to reduce odors by 60–85 percent and to reduce ammonia by 3 15–45 percent. 4

• Filter systems can reduce airborne dust from broile r operations by up to 50 percent. 5

• Biofilters can exhibit 90 percent or better reducti ons of odor-causing chemicals such as 6 hydrogen sulfide, methanethiol, dimethyl sulfide, a nd dimethyl disulfide. 7

• Ionization systems can reduce dust concentrations 6 8–92 percent. 8

• Indoor ozone systems can decrease total dust concen trations by 60 percent and ammonia 9 levels by 58 percent compared to similar buildings without ozone treatment. 10
The authors added that poultry litter amendments su ch as sodium bisulfate and alum can reduce 11 odor and ammonia emissions and natural windbreaks c an provide an entrapment mechanism for 12 odorous compounds that require minimal maintenance. Windbreaks placed downwind of exhaust 13 fans and litter storage areas can may provide an economical management practice for broi ler 14 producers when used in conjunction with other air-c leaning practices. 15
In Kentucky, Singh et al. (2009) reported that addi ng a commercially available urease inhibitor 16 to poultry litter resulted in a significant reducti on in equilibrium ammonia concentration over 17 time by disrupting the enzymatic degradation of uri c acid. 18
Melse and Timmerman (2009) reported average ammonia removal efficiencies of 70

– - 96 percent 19 for farm-scale operated acid scrubbers on swine fac ilities in the Netherlands. Reported average 20 removal efficiency for odor was only 31 percent and showed a large variation. Multi-pollutant 21 scrubbers removed an average of 66 percent of ammon ia, 42 percent of odor, 50 percent of PM 10 , 22 and 57 percent of PM 2.5 . 23
Adrizal et al. (2008) evaluated the potential of tr ees planted around Pennsylvania commercial 24 poultry farms to trap ammonia and dust or particula te matter. Results indicated that poplar, 25 hybrid willow, and Streamco willow are appropriate species to absorb poultry house aerial NH 3 - 26 N, whereas spruce and hybrid willow are effective t raps for dust and its associated odors. 27
Koenig et al. (2005) reported that aluminum sulfate and process controls such as moisture 28 content, carbon source and particle size have poten tial to reduce ammonia loss from poultry 29 manure composted inside high-rise layer structures. Although both low moisture and temperature 30 reduced NH 3 capture, managing temperature and moisture to achi eve low NH 3 would adversely 31 affect impact microbial activity and other desired benefits of c omposting. 32
In a Texas laboratory study, Shi et al. (2001) eval uated amendments for reducing ammonia 33 emissions from open-lot beef cattle feedlots and fo und that cumulative ammonia emissions after 34 21 days compared to the untreated control were : 2–8 percent for alum, 22–29 percent for CaCl 2 , 35 32–40 percent for humate, 34–36 percent for a ureas e-inhibitor NBPT, and 68–74 percent for a 36 commercial product. 37
In North Carolina, Szogi and Vanotti (2007) demonst rated that solid-liquid separation 38 technologies can substantially reduce ammonia emiss ions from anaerobic swine lagoons. 393/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-44 Ammonia emissions from a lagoon with solid-liquid s eparation had 73 percent lower ammonia 1 emissions compared to an anaerobic lagoon. 2
Replacing Replacement of swine waste lagoon technology with cleaner aerobic technology in 3 North Carolina reduced GHG greenhouse gas emissions 96.9 percent—from 4,972 tonnes to 153 4 tonnes of carbon dioxide equivalents (CO 2 -eq)/yr (Vanotti et al. 2008). 53/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-45 Table 2-12. Summary of reported practice effects fo r air quality issues

. 1 Location Study type Practice Practice effects Source Numerous Review Various Scrubbers can reduce odors by 60%–85% and reduce ammonia by 15%–45% Filter systems can reduce airborne dust from broiler operations by up to 50% Biofilters can exhibit 90% or better reductions of odor-causing chemicals Ionization systems can reduce dust concentrations 68%–92% Indoor ozone systems can decrease total dust concentrations by 60% and ammonia levels by 58% compared to similar buildings without ozone treatment Ullman et al. 2004

Netherlands Farm Acid scrubbers Average 70%–96% ammonia removal, 31%

odor removal on swine facilities; multi-pollutant scrubbers removed 66% of ammonia, 42% odor, 50% PM 10 removal, and 57% PM 2.5 Melse and Timmerman 2009

PA Farm Tree windbreaks Poplar, hybrid willow, and Streamco willow absorb poultry house aerial NH 3 -N; whereas spruce and hybrid willow are effective traps for dust and odors. Adrizal et al. 2008

TX Laboratory Beef feedlot amendments 21-day cumulative ammonia emissions

compared to untreated control were: 2–8% for alum, 22–29% for CaCl 2 , 32–40% for humate, 34–36% for a urease-inhibitor NBPT, and 68– 74% for a commercial product. Shi et al. 2001

NC Farm Liquid-solid separation Ammonia emissions from a lagoon with solidliquid separation had 73% lower ammonia emissions compared to an anaerobic lagoon. Szogi and Vanotti 2007

NC Farm Aerobic lagoon Reduced GHG r R educed greenhouse gas

emissions 96.9%, from 4

, 972 t to 153 t of carbon dioxide equivalents (CO 2 -eq)/yr Vanotti et al. 2008

Practice Costs 2 Systematic cost data for most practices are rarely given in the scientific literature; better cost dat a 3 might may be available on a state or county basis from produ cers, groups, or agencies funding or 4 managing implementation. Among reported cost data, there is a lack of consistency in unit costs 5 (e.g., $/cow, $/kg P removed, or $/L of waste treat ed) that sometimes makes comparison among 6 practices difficult. Cost figures are reported in d ollars for the year given by the authors. 7 In laboratory studies
, Jones and Brown (2000) estimated chemical cost (20 08 dollars) for 8 combinations of alum and poylacrylamide ( PAM ) of $73

– - 198/kg orthophosphate-P (ortho-P) 9 removed from dairy wastewater. For supplementary pr ecipitation of soluble P in the treatment of 10 dairy manure by mechanical separation, Oh et al. (2 005) estimated costs for alum and polymer 11 addition of about $2.88 per 1

, 000 L of treated manure slurry. 123/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-46 Moore et al. (2000) found that alum applications to poultry litter was cost-effective, with a 1 benefit/cost ratio of 1.96 due partly from to heavier birds, better feed conversion, and lower 2 energy use to vent ammonia from the houses. 3
In a cost analysis of anaerobic digestion and metha ne production, Garrison and Richard (2005) 4 noted that the economic feasibility of the energy c onversion technology varies widely with scale, 5 with significant advantages for larger facilities. Farrow For swine operations, farrow -to-finish and 6 finishing swine operations needed more than 20,000 head and 5,000 h ead, respectively, to be 7 economically feasible . Dairy operations in the Midwestern U nited States .S. dairy operations hold 8 considerably more economic promise, with feasible h erd counts in the 150- to 350-head range 9 for electricity prices of $0.13/kWh (2008 dollars). Results indicate that increased energy prices 10 and financial assistance will be needed to encourag e significant numbers of facilities to recover 11 energy from manure. 12
Brodie et al. (2000) studied technologies to manufa cture compost from poultry litter and reported 13 that screened compost was produced at an operationa l cost of $37 (2008 dollars) while 14 unscreened compost could be produced for about $25 per ton of compost. A production scheme 15 where poultry litter is static pile composted on fa rms for later transport to regional processing 16 centers appears feasible. 17
Kemper and Goodwin (2009) reported that in composti ng poultry litter and eggshell waste into a 18 marketable soil amendment, compost could be produce d at an average cost of $17.48 to 19 $20.09/ton for small-scale and large-scale systems, respectively. The cost for disposing of 20 eggshell waste in landfills was $25/ton. 21
In a study of using filamentous green algae grown i n outdoor raceways to treat dairy manure 22 effluent, Mulbry et al. (2008) projected annual ope rational costs of $780 per cow. For 23 comparison, the operational costs of $11 per kg N r emoved are well below the costs cited for 24 upgrading existing water treatment plants. 25
Shi et al. (2001) calculated the costs of six amend ments for reducing ammonia emissions from 26 open-lot beef cattle feedlots, ranging from $0.15 t o $6.74 (2008 dollars) per application per head. 27 Only one treatment had a benefit/cost ratio greater than 1.0. Results suggest that amendments can 28 reduce ammonia emissions from open feedlots, but th e costs might may be prohibitive. 29
Vanotti et al. (2008) analyzed GHG greenhouse gas emission reductions from implementing 30 implementation of aerobic technology on swine farms in North Carolina and estimated emission 31 reductions of 4
, 776.6 tonnes CO 2 -eq per year or 1.10 tonnes CO 2 -eq/head per year. The dollar 32 value from implementation was US $19,106/year using current Chicago Climate Exchange 33 trading values of US $4/t CO 2 . That This translates into a direct economic benefit to the p roducer 34 of US $1.75 per finished pig. The authors suggest suggeste d that GHG emission reductions and 35 credits can help compensate for the higher installa tion cost of cleaner aerobic technologies and 36 facilitate producer adoption of environmentally sup erior technologies to replace current 37 anaerobic lagoons. 38
In studies of poultry litter amendments to reduce o dor and ammonia volatilization, Ullman et al. 39 (2004) found that sodium bisulfate and alum treatme nts ranged in price from $220 to $460 per 40 ton (dollar year unknown), resulting in a cost of $ 11 to $16 for 92.9 m 2 (1,000 ft 2 ) at 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-47 recommended application rates. Another cost benefit analysis showed that ammonia reduction by 1 ventilation during cold periods would cost $3,800 p er flock (19,000 birds weighing 4 lb each). 23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-48 

## 3 Implementation Measures and Practices for In-fiel d 1 

## Control 2 The best approach to minimize nutrient transport to local waters depends up on whether the 3 nutrient is in the dissolved phase or is attached t o soil particles. For dissolved nutrients, effectiv e 4 management includes source reduction and reduction of water runoff or leaching. Erosion and 5 sediment transport controls are necessary to reduce transport of nutrients attached to soil 6 particles. Practices that focus on controlling the transport of smaller soil particle sizes (e.g., cla ys 7 and silts) are most effective because they these are the soil fractions that transport the greatest 8 share of adsorbed nutrients. 9



### 3.1 Field Nutrient Management 10 Strategies for in-field control on row crop land fo cus on managing the form, application method, 11 and timing of waste and nutrient applications and o n controlling soil conditions to reduce the 12 potential for runoff of nutrients. Pasture manageme nt strategies address managing animal 13 stocking rates and maintaining vigorous vegetation to provide for soil stability and nutrient 14 recycling. 15

Implementation Measure: Manage nutrient applications to row crop land to m inimize nutrients available for runoff. In doing so, apply manure and chemical fertilizer application during the growing season only, do not apply any manure to fro zen ground, inject or otherwise incorporate all manure or organic fertilizer to minimize the av ailable dissolved P and volatilized N, and do not apply nutrients to HELs.
Implementation Measure : Manage nutrient applications to row crop land to minimize 16 nutrients availab le for runoff. In doing so, apply manure and chemical fertilizer 17 application only during the growing season, do not apply any manure to frozen ground, 18 inject or otherwise incorporate all manure or organic fertilizer to minimize the available 19 dissolved P an d volatilized N, and do not apply nutrients to HELs

. 20
In many row crop areas, nutrient imports in feed an d fertilizers exceed exports in crops 21 produced; that this imbalance often exists at both the individual fiel d and the watershed level 22 (Beegle
, 2000). In such circumstances, nutrients can may accumulate in soils from over23 application of fertilizer or animal waste relative to crop need. Excessive soil nutrient levels have 24 been linked to high P losses in runoff and leaching losses of N, especially in areas of animal25 based agriculture 26
Nutrient management is an important tool to match n utrient inputs more closely to crop needs. 27 The USDA-NRCS Nutrient Management Practice ( NRCS Practice Code 590) generally defines 28 nutrient management as “managing the amount, source , placement, form and timing of the 29 application of nutrients and soil amendments.” The Nutrient Management Practice can may be 30 applied for a number of purposes: 31

• To budget and supply nutrients for plant production ; 323/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-49 • To properly use utilize manure and organic byproducts or biosolids as a pl ant nutrient 1

source ; 2

• To minimize agricultural non-point source pollution of surface and ground water 3

resources 4

• To protect air quality by reducing N nitrogen emissions and the formation of atmospheric 5 particulates ; and 6

• To maintain or improve the physical, chemical, and biological condition of soil 7
This section presents information concerning severa l management practices to manage nutrients 8 on cropland to reduce nutrient losses: 9

• Waste and fertilizer form

— selecting selection of the form of nutrients applied to 10 cropland to reduce runoff or leaching losses ; 11

• Application methods and timing

— selecting selection of the method and/ or timing (or 12 both) of manure or fertilizer application to cropland to support crop growth and reduce 13 runoff or leaching losses ; 14

• Nutrient management planning

— preparing and implementing preparation and 15 implementation of a comprehensive plan to manage nutrients from all sources to provide 16 for crop growth while minimizing runoff and leachin g losses of nutrients ; and 17

• Soil and manure amendment

— treating treatment of

soils or manure to reduce the 18 availability or mobility of nutrients

. 19

Practice Effectiveness 20 Waste and Fertilizer Form and Rate 21

Chien et al. (2009) reviewed recent developments of ferti lizer production and use that improve 22 nutrient efficiency and minimize environmental impa ct. Improving N nutrient efficiency includes 23 using the following: 24

use of : 25

1. • Controlled-release coated urea products
, 26 2. • Slow-release urea-aldehyde polymer products
, 27 3. • Urea supergranules for deep placement
, 28 4. • Nitrification inhibitors (NIs) to reduce nitrate leaching and denitrification
, 5 29 5. • Urease inhibitors to reduce ammonia volatilization from urea , and 30 6. • Ammonium sulfate to enhance N efficiency of urea

. 31
Improving the efficiency of conventional P fertiliz ers includes using the following use of : 32
(1) • Coated
, water-soluble P fertilizers
, 33 (2) • Urea supergranules containing P and K nutrients , and 3 34 (3) • Fluid P fertilizers

. 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-50 Use of nonconventional P fertilizers includes the following : 1
(1) • Phosphate rock (PR) for direct application
, 2 (2) • A mixture of PR and water-soluble P sources
, 3 (3) • Calcined nonapatite PR for direct application , and 4 (4) • Nonconventional acidulated P fertilizers containing water-insoluble but citrate5 soluble P compounds. The use of these nonconvention al fertilizers may result in an 6 increased relative economic benefit with respect to the use of conventional fertilizers in 7 terms of saving fertilizer cost, enhancing nutrient efficiency, or increasing crop yield

. 8
Slow-release fertilizer (SRF) and controlled-releas e fertilizer ( CRF C RY ) materials might may be 9 beneficial to improve nutrient uptake efficiency an d reduce the leaching potential of excess 10 nutrients (Morgan et al. 2009). Those These considerations are particularly important for crop s 11 grown on sandy soils with relatively low nutrient

- and water

- holding capacities 12
In New Zealand, Sojka (2009) compared the efficacy of matrix-based fertilizers (MBFs) 13 formulated to reduce nitrate, ammonium, and total phosphorus ( TP ) leaching with conventional 14 SRFs slow

- release fertilizers (SRF ) ) , and an unfertilized control. SRF leachate contain ed higher 15 amounts of nitrate, ammonium, and TP than leachate from all other fertilizers. There were no 16 consistent differences in the amount of nitrate, am monium, and TP in the MBF leachates 17 compared to the control leachate. 18
Penn et al. (2004) tested the effects of phytase en zyme and HAP corn supplemented diets on 19 runoff P concentrations from Virginia VA pasture soils receiving surface applications of tu rkey 20 manure. The alternative diets caused a decrease in manure total and water-soluble P compared P 21 with the standard diet. Runoff dissolved P concentr ations were significantly higher from HAP 22 manure-amended soils while dissolved P losses from other manure treatments were not 23 significantly different from each other. 24
In a laboratory study, Loria and Sawyer (2005) comp ared the effect of raw and digested liquid 25 swine manure application on soil test P and inorgan ic N. Raw and digested manure produced the 26 same NH 4 -N disappearance, NO 3 -N formation, net inorganic N, and an increase in s oil test P. 27 Routine soil test P methods estimated similar P rec overy with both manure sources. 28
In Iowa, Loria et al. (2007) found no difference be tween raw swine manure and manure digested 29 for biogas as a source of N for plant use in the ye ar of application or in the residual year; 30 equivalence to fertilizer N was the same with both raw and digested swine manure. 31
In Georgia, Risse and Gilley (2000) reported that r unoff was reduced from 1 to 68 percent, and 32 soil loss decreased from 13 to 77 percent for locat ions on which manure was added annually. 33 Measured runoff and soil loss values were found to be strongly influenced by manure application 34 rates. Regression equations were developed relating reductions in runoff and soil loss to manure 35 application rates. 36
In Colorado, Shoji et al. (1999) conducted field trials on CRFs and an a nitrification inhibitor 37 ( NI ) to show their potential to increase NUE. T Total N fertilizer losses averaged 15 and 10 38 percent in the NI and urea treatments, respectively . On the other hand, those from the CRF 393/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-51 treatment averaged only 1.9 percent, indicating tha t CRF showed the highest potential to increase 1 N use efficiency. 2
King and Torbert (2007) reported an OH plot study w as designed to compare temporal losses of 3 NO 3 -N and NH 4 -N from three SRFs slow

- release fertilizers (sulphur-coated urea, composted 4 dairy manure, and poultry litter) and one fast-rele ase fertilizer (ammonium nitrate) applied to 5 Bermuda bermuda

grass turf. Cumulative NO 3 -N loss from plots receiving application of the 6 manufactured (NH 4 NO 3 and sulphur-coated urea) products was significantl y greater than the 7 measured losses from plots receiving application of composted dairy manure and poultry litter. 8 The cumulative NO 3 -N recovered in the runoff expressed as a proportio n of applied N was 0.37 9 for ammonium nitrate, 0.25 for sulphur-coated urea, 0.10 for composted dairy manure, and 0.07 10 for poultry litter. 11

Table 2-13. Summary of reported practice effects re sulting from management of waste and 12 fertilizer form and rate

. 13

Location Study

type Practice Practice effects Source New Zealand Plot Fertilizer formulation Leachate from conventional SRFs slow

- release

fertilizers contained higher amounts of nitrate, ammonium, and TP than leachate from all other fertilizers Sojka 2009

VA Field Poultry litter from phytase and HAP feeding Alternative diets decreased manure total and

water-soluble P compared with the standard diet. Runoff dissolved P concentrations were significantly higher from HAP manure-amended soils than from phytase manure applications, while dissolved P losses from other manure treatments were not significantly different from each other. Penn et al. 2004

IA Laboratory Raw vs. digested swine
manure Raw and digested manure produced the same

NH 4 -N disappearance, NO 3 -N formation, net inorganic N, and an increase in soil test P. Routin e soil test P methods estimated similar P recovery with both manure sources. Loria and Sawyer 2005

IA Plot Raw vs. digested swine
manure No difference between raw swine manure and

manure digested for biogas as a source of N for plant use in the year of application or in the residual year; equivalence to fertilizer N was the same with both raw and digested swine manure. Loria et al. 2007

GA Fields Manure application rates Runoff was reduced from 1 % –68%, and soil loss

decreased from 13 % –77% where manure was added annually. Measured runoff and soil loss values were found to be strongly influenced by manure application rates; regression equations were developed relating reductions in runoff and soil loss to manure application rates. Risse and Gilley 2000

CO Field trials CRF, NIs Controlle d release fertilizer, nitrification inhibitors T Total N fertilizer losses averaged 15 % and 10%

in the NI nitrification inhibitor and urea treatments, respectively. N losses from the controlled release fertilizer treatment averaged only 1.9% Shoji et al. 19993/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-52 OH Plot SRFs Slow release fertilizers Cumulative NO 3 -N loss from plots receiving

application of manufactured (NH 4 NO 3 and sulphurcoated urea) products was significantly greater than the measured losses from plots receiving application of composted dairy manure and poultry litter. The cumulative NO 3 -N recovered in the runoff expressed as a proportion of applied N was 0.37 for ammonium nitrate, 0.25 for sulphur-coated urea, 0.10 for composted dairy manure, and and 0.07 for poultry litter. King and Torbert 2007

Nutrient Application Methods and Timing 1
In soil column and field studies in New York, Geohr ing et al. (2001) reported that high P 2 concentrations observed in tile drain effluent soon after dairy manure application can be 3 attributed to macropore transport processes. Plowin g-in manure apparently disturbs these 4 macropores and promotes matrix flow, resulting in g reatly reduced P concentrations in the 5 drainage effluent. 6
In New York, Lewis and Makarewicz (2009) reported s ignificant decreases in winter 7 concentrations of T total P, soluble P, TKN, and NO 3 -N but not TSS following cessation of 8 winter dairy manure application to cropland. 9
Chen and Samson (2002) investigated the effects of fertilizer source and manure application 10 timing, rate, and method on soil nutrient concentra tions, corn grain yields, and groundwater 11 nitrate concentrations in Ontario, Canada. In gener al, higher NO 3 -N concentrations were 12 observed in those plots where N nitrogen sources had been applied shortly before soil sampl ing. 13 Trends of residual NO 3 -N concentrations varied among experiments, and res ults were 14 inconclusive. Two-fold higher P concentrations were observed in the manured plots than in the 15 inorganically fertilized plots as a result of highe r P 2 O 5 inputs from swine manure. 16
In Kansas plots, Reiman et al. (2009) tested the effect impact of manure placement depth on corn 17 and soybean yield and N retention in soil. The net effect impact of placement on T total N was 18 that deep manure injection treatments had 31–59 mor e kg N/ha than the shallow injection 19 treatment 12 to 30 months after application. Higher corn yield in the deep

- injected treatment 20 was attributed to increased N use efficiency. Highe r inorganic N amounts in the deep injection 21 treatment were attributed to reduced N losses throu gh ammonia volatilization, leaching, or 22 denitrification. 23

Ali et al. (2007) tested simplified surface irrigation of dairy farm effluents in Quebec, Canada
, 24 and reported that seepage losses represented less t han 1 percent of the total volume of effluents 25 applied, nutrients and bacteria applied were lost i n subsurface drainage, implying a treatment 26 efficiency of > 99 percent compared to conventional land spreading. 27
In an Ontario, Canada
, plot study, Coelho et al. (2006) determined the ef fects of rate and method 28 of sidedress application of liquid swine manure on N recovery by corn using in-row injection or 29 topdressing to sidedress manure. Coelho et al. (200 6) measured grain N uptake and NO 3 -N in 30 drainage water, stalks, and topsoil postharvest. Ap parent recovery of manure T total N was 31 greater with injection (59 percent) than topdress ( 41percent) and transport of N to ground water

- 323/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-53 and surface water waters was minimized when sidedressed at or below rates f or optimal yield. 1 When injected N exceeded crop demand, NO 3 -N increased to over 10 mg/kg in topsoil, 20 mg/L 2 in drainage water, and to excessive (3.6 g/kg) leve ls in stalks. 3
Drainage NO 3 -N concentration and load increased linearly by 0.6 9 mg NO 3 -N/L and 4.6 kg NO 3 - 4 N/ha, respectively, for each 10 kg N/ha applied ove r the minimum of 275 kg N/ha in trials of 5 swine waste application to corn in Spain (Dauden et al.2004). An increase in irrigation efficiency 6 did not induce a significant increase of leachate c oncentration and the amount of nitrate leached 7 decreased about 65 percent. Application of low manu re doses before sowing complemented with 8 sidedressing N application and good irrigation mana gement are the key factors to reduce nitrate 9 contamination of water courses. 10
Soil injection of swine manure on soybeans in Illin ois compared with surface application 11 resulted in runoff concentration decreases of 93, 8 2, and 94 percent, and load decreases of 99, 12 94, and 99 percent for dissolved P, T total P and algal-available P, respectively (Daverede et al. 13 2004). Incorporating Incorporation of inorganic P fertilizer also reduced P concentration in 14 runoff significantly. Runoff P concentration and lo ad from incorporated amendments did not 15 differ from the control. 16
Allen and Mallarino (2008) assessed total runoff P, bioavailable P, and dissolved P 17 concentrations and loads in surface runoff after li quid swine manure application with or without 18 incorporation into soil and different timing of rai nfall in Illinois IL . For events 24 hours after 19 application, P concentrations were 2 to 5 times hig her for nonincorporated manure than for 20 incorporated manure; P loads were 3.8 to 7.7, and 3 .6 times higher. A 10- to 16-day rainfall 21 delay resulted in P concentrations that were ~3 time s lower than for 24-hour events across all 22 nonincorporated P rates. 23
Andraski et al. (2003) investigated the effects of manure history and tillage on P levels in runoff 24 from continuous corn in Wisconsin. Soil P levels in creased with the frequency of manure 25 applications and P stratification was greater near the surface in no-till than in chisel plow. In 26 chisel plow, soil test P level was linearly related to dissolved P and bioavailable P loads in 27 runoff. In no-till, P loads were reduced by an aver age of 57 percent for dissolved P, 70 percent 28 for bioavailable P, and 91 percent for T total P compared with chisel plow. 29
In an Iowa plot study, Bakhsh et al. (2009) determined the effects of swine manur e application to 30 corn and soybeans on NO 3 -N concentrations in subsurface drainage water and corn-soybean 31 yields. Average flow-weighted NO 3 -N concentrations and leaching losses increased by > 50 32 percent when manure was applied to both corn and so ybean compared to manure application to 33 corn only, while yield differences were less than 4 percent. Those These results suggest that fall 34 manure application to both corn and soybean is like ly to increase NO 3 -N leaching to shallow 35 groundwater without resulting in significant yield benefits. 36
Kleinman et al. (2009) evaluated losses of P in sub

- surface and surface flow as a function of 37 dairy manure application to no-till soils in Pennsy lvania. Incorporation of manure by tillage 38 lowered P loss in leachate relative to broadcast ap plication because of due to the destruction of 39 preferential flow pathways. In contrast, rainfall s imulations on runoff plots showed that T total P 40 losses in surface runoff differed significantly by soil but not by application method. Results 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-54 confirm the near-term benefits of incorporating man ure by tillage to protect groundwater quality
, 1 but suggest that for surface water quality, avoidin g soils prone to runoff is more important. 2

Warren et al. (2008) compared surface broadcast litter app lication and subsurface litter banding 3 on grassland in Alabama. Subsurface band applicatio ns resulted in forage yields equivalent to 4 those achieved by conventional broadcast litter app lications and did not significantly alter the 5 Mehlich 3 extractable nutrient content of soils col lected at a depth of 0 to 15 cm. 6
In Arkansas, Pote et al. (2003) determined effects of poultry litter incorporation into Bermuda 7 bermuda grass and mixed forage plots on quantity and qualit y of runoff water. Nutrient 8 concentrations and mass losses in runoff from incor porated litter were 80–95 percent less than in 9 runoff from surface-applied litter. Litter-incorpor ated soils had greater rain infiltration rates, 10 water-holding capacities, and sediment retention th an soils receiving surface-applied litter. In a 11 subsequent study, Pote et al. (2009) confirmed that fully mechanized litte r subsurface banding 12 increased forage yield while decreasing nutrient N and P loss in runoff by at least 90 percent 13 compared to surface-broadcast litter. 14

Sistani et al. (2009) evaluated the effect of broiler litte r application method and the runoff timing 15 on nutrient and E. coli losses from Alabama perennial grassland. TP, inorg anic N, and E. coli 16 concentrations in runoff from broadcast litter appl ication were all significantly greater than from 17 subsurface litter banding. TP losses from broadcast litter applications averaged 6.8 times greater 18 than those from subsurface litter applications. Ave rage NO 3 -N and TSS losses from subsurface 19 banding were reduced by 64 percent and 68 percent, respectively
, compared to the broadcast 20 method. 21
In soil columns, Guo et al. (2009) evaluated nutrient release dynamics o f Delmarva poultry litter 22 under local weather conditions. Release of most nut rients occurred principally in the first 100 23 days, but for P, release would last for years. The nutrient supply capacity of surface-applied 24 Delmarva poultry litter was predicted at 10.9 kg N/ Mg and 6.5 kg P/Mg. The results suggest that 25 Delmarva poultry litter should be applied to conser vation tillage systems at 6.6 Mg/ha that would 26 furnish 25 kg P/ha and 63 kg N/ha to seasonal crops . In repeated annual applications, the rate 27 should be reduced to 5.2 Mg/ha, with supplemental N fertilization to meet crop N requirements. 28

Kaiser et al. (2009) assessed P loss immediately after pou ltry manure application to soybean 29 residue with and without tillage at eight Iowa IA fields. Non

- incorporated manure consistently 30 increased concentrations of all runoff P fractions in five sites. On average manure increased 31 dissolved P, bioavailable P, and TP total P 32, 23, and 12 times, respectively, over the contr ol. 32 Tillage to incorporate manure reduced dissolved P, bioavailable P, and T total P by 88, 89, and 77 33 percent on average , respectively

. 34
In a Georgia plot study, Franklin et al. (2006) reported that soil aeration reduced r unoff volume 35 by 27 percent in the first runoff event but the eff ect disappeared after one 1 month; aeration did 36 not affect the mass losses of dissolved reactive P ( DRP ) , TKN, or NH 4 -N from plots fertilized 37 with either inorganic fertilizer or poultry litter. 38

Franklin et al. (2007) evaluated the effects of slit aeratio n on runoff volume and P losses from 39 fescue fertilized with broiler litter in Georgia GA . In the field with mostly well-drained soils, 40 grassland aeration reduced surface runoff volume an d mass losses of DR dissolved reactive 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-55 dissolved P in runoff by 35 percent. However, on poorly drain ed soils, grassland aeration 1 increased runoff volume and mass losses of dissolve d and TP total P

. 2

Butler et al. (2008a) evaluated the effects of three aeration tre atments on export of TSS and P 3 from grassland plots receiving broiler litter and d airy slurry in Georgia GA . Core aeration 4 reduced export of T total P by 55 percent, dissolved P by 61 percent, and bio available P 54 5 percent plots with applied broiler litter as compar ed with the control. Core and no-till disk 6 aeration also showed potential for reducing P expor t from applied dairy slurry. 7
In British Columbia, Canada, van Vliet et al. (2006) studied the effect of mechanically ae rating 8 grassland before liquid manure application in on su rface runoff and transport of nutrients and 9 solids. Annual runoff amounts were reduced by 47–81 percent, suspended and volatile solid 10 loads by 48–69 percent and 42–83 percent, respectiv ely, TKN loads by 56–81 percent, and T total 11 P loads by 25–75 percent. Loads of the soluble nutr ient NH 4 -N, DR dissolved reactive P, and K 12 were reduced by 41–83 percent. 13

Table 2-14. Summary of reported practice effects re sulting from management of nutrient 14 application methods and timing

. 15

Location Study

type Practice Practice effects Source NY Soil

column, field Manure

incorporation Plowing-in manure apparently disturbs macropores

and promotes matrix flow, resulting in greatly reduced P concentrations in tile drainage effluent. Geohring et al. 2001

NY Field Cessation of winter
manure spreading Significant decreases in winter concentrations of

T total P, soluble P, TKN, and NO3-N but not TSS following cessation of winter dairy manure application to cropland. Lewis and Makarewicz 2009

Ontario Plots Nutrient source and timing Higher NO 3 -N concentrations observed in plots

where N sources applied shortly before soil sampling. Trends of residual NO 3 -N concentrations varied among experiments, and results were inconclusive. Two-fold higher P concentrations were observed in the manured plots than in the inorganically fertilized plots as a result of highe r P 2 O 5 inputs from swine manure. Chen and Samson 2002

KS Plots Manure placement depth Deep manure injection treatments had 31–59 more

kg N/ha than the shallow injection treatment 12–30 months after application. Higher corn yield in the deep injected treatment attributed to increased N use efficiency. Higher inorganic N amounts in deep injection treatment attributed to reduced N losses through ammonia volatilization, leaching, or denitrification Reiman et al. 2009

Quebec, Canada Fields Irrigation of dairy effluent Seepage losses represented < 1% of the total

volume of effluents, nutrients and bacteria applied implying a treatment efficiency of >99% compared to conventional land spreading. Ali et al. 20073/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-56 Location Study

type Practice Practice effects Source Ontario, Canada Plot Liquid
manure injection Apparent recovery of manure T total N was greater

with injection (59%) than topdress (41%) and transport of N to ground- and surface waters was minimized when sidedressed at or below rates for optimal yield. When injected N exceeded crop demand, NO 3 -N increased to over 10 mg/kg in topsoil, 20 mg/L in drainage water, and to excessive (3.6 g/kg) levels in stalks Coelho et al. 2006

Spain Plot Waste irrigation Drainage NO 3 -N concentration and load increased

linearly by 0.69 mg NO 3 -N/L and 4.6 kg NO 3 -N/ha, respectively, for each 10 kg N/ha applied over the minimum of 275 kg N/ha. An increase in irrigation efficiency did not induce a significant increase of leachate concentration and the amount of nitrate leached decreased about 65%. Dauden et al.2004

IL Plots Manure injection Soil injection of swine manure on soybeans

compared with surface application resulted in runoff P concentration decreases of 82 % –99%. Daverede et al. 2004

IL Plots Manure incorporation For events 24- hours hr after application, P

concentrations were 2 to 5 times higher for nonincorporated manure than for incorporated manure; P loads were 3.8 to 7.7, and 3.6 times higher. Allen and Mallarino 2008

WI Field Manure history, tillage Soil P levels increased with the frequency of

manure applications. In no-till, P loads were reduced by an average of 57% for dissolved P, 70% for bioavailable P, and 91% for T total P compared with chisel plow Andraski et al. 2003

IA Plot Manure application timing NO 3 -N concentrations and leaching losses

increased by > 50% when manure applied to both corn and soybean compared to manure application to corn only, while yield differences were less tha n 4%. Fall manure application to both corn and soybean is likely to increase NO 3 -N leaching to shallow groundwater without resulting in significan t yield benefits. Bakhsh et al. 2009

PA Plots Manure incorporation by tillage Incorporating Incorporation of manure by tillage

lowered P loss in leachate relative to broadcast application from due to the destruction of preferential flow pathways; T total P losses in surface runoff differed significantly by soil but n ot by application method Kleinman et al. 2009

AL Field Subsurface banding of poultry litter Subsurface band applications resulted in forage

yields equivalent to conventional broadcast litter applications and did not significantly alter the Mehlich 3 extractable nutrient content of soils. Warren et al. 20083/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-57 Location Study

type Practice Practice effects Source AR Plots Poultry litter incorporation Nutrient concentrations and mass losses in runoff

from incorporated litter were 80 %–

- 95% less thanin runoff from surface-applied litter. Litterincorporated soils had greater infiltration rates, water-holding capacities, and sediment retention than soils receiving surface-applied litter Pote et al. 2003, 2009

AL Plots Subsurface banding of poultry litter TP, inorganic N, and E. coli concentrations in runoff from broadcast litter application exceeded those from subsurface litter banding. TP losses from broadcast litter applications averaged 6.8 times greater than those from subsurface litter applications. Average NO 3 -N and TSS losses from subsurface banding were reduced by 64% and 68%, respectively
, compared to the broadcast method. Sistani et al. 2009

Delmarva Soil

columns Litter

application rate Release of most nutrients occurred principally in

the first 100 days, but for P, release would last f oryears. The nutrient supply capacity of surfaceapplied Delmarva poultry litter was predicted at 10.9 kg N/Mg and 6.5 kg P/Mg; the results suggest that Delmarva poultry litter should be applied to conservation tillage systems at 6.6 Mg/ha that would furnish 25 kg P/ha and 63 kg N/ha to seasonal crops. In repeated annual applications, the rate should be reduced to 5.2 Mg/ha, with supplemental N fertilization to meet crop N requirements Guo et al. (2009)

IA Fields Poultry litter application & tillage Non

- incorporated manure consistently increased

concentrations of all runoff P fractions in five si tes; on average manure increased dissolved P, bioavailable P, and TP total P 32, 23, and 12 times, respectively, over the control. Tillage to incorpor ate manure reduced dissolved P, bioavailable P, and T total P by 88, 89, and 77% on average Kaiser et al. 2009

GA Plot Soil aeration Soil aeration reduced runoff volume by 27% in the first runoff event but the effect disappeared after
one 1 month; aeration did not affect the mass losses of DRP, TKN, or NH4-N from plots fertilized with either inorganic fertilizer or poultry litter Franklin et al. 2006

GA Field Soil aeration, broiler litter On well-drained soils, grassland aeration reduced

surface runoff volume and mass losses of DR dissolved reactive dissolved P in runoff by 35%. However, on poorly drained soils, grassland aeration increased runoff volume and mass losses of dissolved and TP total P Franklin et al. 2007

GA Plots Soil aeration Core aeration reduced T total P export by 55%, dissolved P by 61 %, and bioavailable P by 54% plots with applied broiler litter. Core and no-till disk aeration also showed potential for reducing P export from applied dairy slurry. Butler et al. 2008a3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-58 Location Study

type Practice Practice effects Source British Columbia, Canada Field Soil aeration For mechanically aerating grassland before liquid manure application, annual runoff amounts were reduced by 47–81%, suspended and volatile solid loads by 48–69% and 42–83%, respectively, TKN loads by 56–81%, and T total P loads by 25–75%. Loads of the soluble nutrient NH 4 -N, DR dissolved reactive P, and K were reduced by 41- 83%. van Vliet et al. 2006

1

Implementation Measure: Control soil conditions by using soil amendments t o influence P bound to soil. Implementation Measure: Control soil conditions by using soil amendments to influence P 2 bound to soil. 3
Because runoff losses of P are strongly influenced by the quantity and form of P in the soil 4 (Sharpley 1995 ; , Pote et al. 1996), reducing P runoff from row crop land can may be 5 accomplished by influencing soil test P levels thro ugh soil amendments that change the 6 availability of P and through nutrient management p lanning. 7

Practice Effectiveness 8
Soil and Manure Amendment 9 In Arkansas plots, Haustein et al. (2000) surface application of treatment resi duals and HiClay 10 Alumina to soil plots high in P decreased Mehlich 3 soil test P levels and the two highest rates of 11 WTR water treatment residuals decreased runoff P levels below those of the contro l plots.

. 12
From a Texas field experiment, Brauer et al. (2005) reported that annual additions of gyp sum at 13 5.0 Mg/ha significantly reduced soil-dissolved P, a lthough soil amendment did not affect Bray-1 14 P values. Elliott et al. (2002) conducted laboratory and greenhouse s tudies of the ability of WTR 15 water treatment residuals to alter P solubility and leaching in a Texas soil amended with 16 biosolids and triple superphosphate. Without residu al amendment, 21 percent of soluble P and 11 17 percent of biosolids T total P leached over 4 months. With co-applied residuals, soluble P losses 18 were reduced to < 1–3.5 percent of applied P. Amend ment with residuals retarded downward P 19 flux such that leachate P was not statistically dif ferent than for control (soil only) columns. 20
In North Carolina, Novak and Watts (2004) conducted laboratory experiments to determine if 21 WTR water treatment residuals mixed into soils could significantly increase their P sorption 22 capacities. Mixing residuals into soils increased t heir P-max values several-fold (between 1.7 to 23 8.5 mg P/g) relative to soils with no WTR addition. The authors suggested that WTR 24 incorporation into sandy soils has the potential to be a new chemical-based best management 25 practice ( BMP ) for reducing off-site P transport. 26
Novak and Watts (2005) evaluated the ability of alu m-based WTR water treatment residuals to 27 reduce soil P concentrations in three P-enriched No rth Carolina Coastal Plain soils. Incorporating 28 Incorporation of residuals into the soils caused a near linear and s ignificant reduction in soil P 293/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-59 concentrations. In two soils, 6 percent WTR applica tion caused a soil Melich 3 P concentration 1 decrease to below the soil P threshold. 2
Adding WTR Addition of water treatment residuals to Oklahoma soil plots treated with poultry 3 litter reduced runoff P by from 14–85 percent (Dayt on et al. 2003). Reductions in runoff P were 4 strongly correlated with P-max and Al-ox. Performan ce of treatment residuals as a P sorbent to 5 reduce runoff P from manured land can be estimated from their P-max or Al-ox content. 6
In a Connecticut laboratory study, Hyde and Morris (2000) reported that WTR water treatment 7 residuals significantly reduced Mehlich 3 P concentrations w hen added to soils. Adding residuals 8 to soils reduced soil P concentrations by 23–64 per cent, depending on how the residuals were 9 dewatered. 10
Adler and Sibrell (2003) tested the use of floccula nts (flocs) resulting from neutralizing acid 11 mine drainage (AMD) (as a possible low-cost amendme nt to reduce the loss of soluble P from 12 agricultural fields and animal wastewater) in West Virginia. About 70 percent of water13 extractable P was sequestered by the floc when appl ied to agricultural soils at a rate of 20 g 14 floc/kg soil, whereas plant-available P decreased b y 30 percent. Under anaerobic conditions 15 simulating manure storage basins, all AMD flocs red uced soluble P by greater than 95 percent. 16
At two Michigan field sites with a history of heavy manure applications, amendment with 17 WTR water treatment residuals reduced water-soluble P concentration by > 60 percent as 18 compared to the control plots, and the residuals-im mobilized P remained stable 7.5 yr years after 19 residuals application (Agyin-Birikorang et al. 2007). 20

Staats et al. (2004) investigated the efficacy of alum-ame nded poultry litter in reducing P release 21 from three Delaware Coastal Plain soils. Long-term desorption (25 days ) ) of the incubated 22 material resulted in ~13 percent reductions in cumul ative P desorbed when comparing soil 23 treated with unamended poultry litter. In addition, the P release from the soil treated with alum24 amended litter was not significantly different from the control (soil alone). 25
Zvomuya et al. (2006) tested the P-binding ability of vario us amendment materials in a 26 laboratory soil incubation experiment. Lysimeter br eakthrough tests using tertiary-treated potato27 processing wastewater showed that alum application reduced leachate TP and SR soluble reactive 28 P concentrations by 27 percent and 25 percent, resp ectively. 29

Table 2-15. Summary of reported practice effects re sulting from soil and manure amendment

. 30 Location Study type Practice Practice effects Source AR Plot Soil amendments Surface application of treatment residuals and

HiClay Alumina to high P soils decreased soil test P levels; the highest rates of WTR water treatment residuals decreased runoff P levels below those of the control plots. Haustein et al. 2000

TX Field Gypsum amendment Annual additions of gypsum at 5.0 Mg/ha

significantly reduced soil dissolved P, although soil amendment did not affect Bray-1 P values. Brauer et al. 20053/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-60 Location Study type Practice Practice effects Source TX Laboratory,

greenhouse WTR Water

treatment residuals Without residual amendment, 21% of soluble P

and 11% of biosolids T total P leached over 4 months; with co-applied residuals, soluble P losses were reduced to < 1%–3.5% of applied P. Amendment with residuals retarded downward P flux such that leachate P was not statistically different than for control (soil only) columns. Elliott et al. 2002

NC Laboratory WTR Water treatment residuals Mixing residuals into soils increased their P-max

values several-fold (between 1.7 to 8.5 mg P/g) relative to soils with no WTR addition. Novak and Watts 2004

NC Laboratory WTR Water treatment residuals Incorporation of residuals into soils caused a

near linear and significant reduction in soil P concentrations. In two soils, 6% WTR application caused a soil Melich 3 P concentration decrease to below the soil P threshold. Novak and Watts 2005

OK Plots WTR Water treatment
re siduals Addition of WTR water treatment residuals to OK

soil plots treated with poultry litter reduced runo ff P by from 14–85% Reductions in runoff P were strongly correlated with P-max and Al-ox. Performance of treatment residuals as a P sorbent to reduce runoff P from manured land can be estimated from their P-max or Al-ox content. Dayton et al. 2003

CT Laboratory WTR Water treatment residuals Adding residuals to soils reduced soil P

concentrations by 23–64%, depending on how the residuals were dewatered. Hyde and Morris 2000

WV Laboratory Neutralized AMD flocs ~70% of water-extractable P was sequestered by

the floc when applied to agricultural soils at a ra te of 20 g floc/kg soil; plant-available P decreased by 30%. Under anaerobic conditions simulating manure storage basins, AMD flocs reduced soluble P by > 95%. Adler and Sibrell 2003

MI Field WTR Water treatment residuals Amendment reduced water-soluble P

concentration by > 60% vs. control plots, and the residuals-immobilized P remained stable for 7.5 yr. AgyinBirikorang et al. 2007

DE Laboratory Alum amendment ~13% reductions in cumulative P desorbed vs.

soil treated with unamended poultry litter. P release from soil treated with alum-amended litter was not significantly different from the control (soil alone). Staats et al. (2004)

Various Laboratory Alum soil amendment Lysimeter breakthrough tests showed that alum

application reduced leachate TP and SR soluble reactive P concentrations by 27% and 25%, respectively Zvomuya et al. 2006

Nutrient Application Planning 1 In a Virginia field study, Maguire et al. (2008) in vestigated how changing nutrient management 2 from an N to a P basis affected crop yields and soi l properties in high P soils over a 7-year 33/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-61 period. After 7 years, Mehlich 1 P and water-solubl e P were greatest in soils under the N-based 1 treatments, smallest in the no-P treatment, and int ermediate in the P-based treatments; there were 2 no significant differences between inorganic fertil izer and poultry litter nutrient sources. The 3 results show that soil test P can be decreased in h igh-P soils over a few years by changing from 4 an N-based to a P-based nutrient management plan or stopping P applications without negatively 5 affecting yields. 6
In Quebec, Canada, Giroux and Royer (2007) measured the effect of three P fertilizer rates on 7 crop yields and evolution of the soil test values, saturation and P solubility. Soil test P values 8 decreased by 11–33 percent over 8 years, even at P application rates above crop removal. Annual 9 rates of P saturation decrease were 1.087, 0.891 an d 0.750 percent/yr respectively for the 0, 30, 10 and 60 kg P 2 O 5 /ha fertilizer rates. The P saturation value of 13. 1 percent of the Quebec 11 regulation is achieved after 10 years for the 0 kg P 2 O 5 /ha rate 12
In Texas, Choi et al. (2003) reported that 46–77 percent of the ap plied manure P was removed in 13 a single turfgrass sod harvest. Total dissolved P c oncentrations in the runoff were directly related 14 to P concentrations in the soil. A total of 3.8 per cent of the applied P from composted dairy 15 manure was lost in the surface runoff. 16
From Texas plot studies, McFarland and Hauck (2004) reported that using use of only 17 commercial N on soils with high extractable P level s decreased P loadings in edge-of-field runoff 18 by > 40 percent. However, no notable changes in extract able soil P concentrations were observed 19 after 5 five years of monitoring because of due to drought conditions limiting forage uptake and 20 removal. 21
In a Texas study using an integrated economic and e nvironmental modeling system across 22 multiple ecoregions, Osei et al. (2008) suggested that edge-of-field T total P losses can be 23 reduced by about 0.8 kg/ha/year or 14 percent when manure applications are calibrated to supply 24 all of the recommended crop P requirements from manure T total P sources only, when compared 25 to manure applications at the recommended crop N ag ronomic rate. 26

Table 2-16. Summary of reported practice effects re sulting from nutrient application planning

. 27

Location Study

type Practice Practice effects Source VA Field P-based

nutrient management After 7 yr, Mehlich 1 P and water soluble P were

greatest in soils under the N-based treatments, smallest in the no P treatment, and intermediate in the P-based treatments. Soil test P can bedecreased in high-P soils by changing from an Nbased to a P-based nutrient management plan or stopping P applications without negatively affectin g yields. Maguire et al. 2008

Quebec, Canada Field P fertilizer

rates Soil test P values decreased by 11 % –33% over 8

years, even at P application rates above crop removal. Annual rates of P saturation decrease were 1.087, 0.891 and 0.750%/yr

, respectively
, for the 0, 30, and 60 kg P 2 O 5 /ha fertilizer rates. The P saturation value of 13.1% of the Quebec regulation is achieved after 10 years for the 0 kg P 2 O 5 /ha rate Giroux and Royer 2007

TX Field Turfgrass sod 46 % to 77% of the applied manure P removed in a Choi et al.3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-62

export single turfgrass sod harvest. Total dissolved P

concentrations in the runoff were directly related to P concentrations in the soil. 3.8% of the applied P from composted dairy manure was lost in the surface runoff. 2003

TX Plot Zero P fertilizer Using Use of only commercial N on soils with highextractable P levels decreased P loadings in edgeof-field runoff by > 40%. McFarland and Hauck 2004
TX Model P-based

manure management Edge-of-field T total P losses can be reduced by

about 0.8 kg/ha/year or 14% when manure applications are calibrated to supply all of the recommended crop P requirements from manure T total P sources only, versus vs, manure applications at N agronomic rate. Osei et al. 2008



### 3.2 Sediment and Erosion Control 1

Sediment loss is the result of erosion. It is the s olid material, both mineral and organic, that is in 2 suspension, is being transported, or has been moved from its site of origin by wind, water, 3 gravity, or ice. The types of erosion associated wi th agriculture that produce sediment are (1 ) ) 4 sheet and rill erosion, (2) ephemeral and classic g ully erosion, (3) wind erosion, and (4 ) ) 5 streambank erosion. Soil erosion can be characteriz ed as the transport of particles that are 6 detached by rainfall, flowing water, or wind. Erode d soil is either redeposited on the same field 7 or transported from the field in runoff or by wind. 8
The strategies for controlling erosion and sediment ation involve reducing soil detachment, 9 reducing sediment transport, and trapping sediment before it reaches water. The first objective 10 for both water and wind erosion is to keep soil on the field, and the easiest and often most 11 effective strategy to accomplish this is to reduce soil detachment. Detachment occurs when water 12 splashes onto the soil surface and dislodges soil p articles
, or when wind reaches sufficient 13 velocity to dislodge soil particles on the surface. 14
Crop residues (e.g., straw) or living vegetative co ver (e.g

. ., grasses) on the soil surface protect 15 against detachment by intercepting and/or dissipati ng the energy of falling raindrops. A layer of 16 plant material also creates a thick layer of still air next to the soil to buffer against wind erosion

. 17 Some practices have considered crop substitution th at maintains a greater surface coverage. 18
Implementing The implementation of practices such as conservation tillage also preserv es or 19 increases organic matter and soil structure, result ing in improved water infiltration and surface 20 stability. In addition, creating creation of a rough soil surface through practices such as surf ace 21 roughening will break the force of raindrops and tr ap water, reducing runoff velocity and erosive 22 forces. 23
Sediment transport can be reduced in several ways, including using the use of crop residues or 24 conservation buffers. Vegetation slows runoff, incr eases infiltration and traps sediment. 25 Reductions in slope length and steepness reduce run off velocity, thereby reducing sediment 26 carrying capacity as well. Practices are also typic ally needed to trap sediment leaving the field 273/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-63 before it reaches a wetland or riparian area. Depos ition of sediment is achieved by practices that 1 slow water velocity or increase infiltration. 2
Properly functioning natural wetlands and riparian areas can significantly reduce nonpoint source 3 pollution by intercepting surface runoff and subsur face flow and by settling, filtering, or storing 4 sediment and associated pollutants. Wetlands and ri parian areas typically occur as natural buffers 5 between uplands and adjacent water water bodies. Loss of these systems allows a more direct 6 contribution of nonpoint source pollutants to recei ving waters. Degraded wetlands and riparian 7

areas can may even become pollutant sources. Thus, natural wetlan ds and riparian areas should 8 be protected and should not be used as designated e rosion control practices. Their nonpoint 9 source control functions are most effective as part of an integrated land management system 10 focusing on nutrient, sediment, and erosion control practices applied to upland areas. 11
Additional descriptions of erosion and sediment con trol practices are can be found in previous 12 guidance (USEPA
, 2003). 13

Implementation Measure: Use conservation tillage or continuous no-till on all row crops to reduce soil erosion and sediment loads except on th ose lands that have no erosion or sediment loss.

Implementation Measure : Use conservation tillage or continuous no

- till on all row crops to reduce soil 14 erosion and sediment loads ex cept on those lands that currently have no erosion or sed iment loss

. 15

Conservation tillage involves little, if any, tilla ge in the row crop field, whereas continuous no16 till leaves all residue after harvest on the field, protecting the soil. In general, conservation till age 17 is any tillage system that maintains 30 percent or more of the soil surface with crop residue after 18 planting (USDA-NRCS
, 2010). The amount of residue needed to achieve ero sion and sediment 19 reduction goals, however, is dependent up on numerous factors, and the Revised Universal Soil 20 Loss Equation (RUSLE) is a tool that can help determine assist in determining the amount left on 21 the field. 22
Water erosion rates are affected by rainfall energy , soil properties, slope, slope length, vegetative 23 and residue cover, and land management practices. R ainfall impacts provide the energy that 24 causes initial detachment of soil particles. Soil p roperties like particle size distribution, texture, 25 and composition influence the susceptibility of soi l particles to be moved by flowing water. 26 Vegetative cover and residue can may protect the soil surface from rainfall impact or t he force of 27 moving water. Those These factors are used in the Revised Universal Soil Loss Equation 28 ( RUSLE ) , an empirical formula widely used to predict soil loss in sheet and rill erosion from 29 agricultural fields, primarily crop land and pastur e, and construction sites (USDA-ARS
, 2005): 30
Revised Universal Soil Loss Equation (RUSLE) 31 A = R × * K × * LS × * C × * P 32

where 33

Where 34

A = estimated average annual soil loss (tons/acre/ye ar) 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-64 R = rainfall/runoff factor, quantifying the effect o f raindrop impact and the amount and rate 1 of runoff associated with the rain, based on long t erm rainfall record 2

K

= soil erodibility factor based on the combined ef fects of soil properties influencing 3 erosion rates 4

LS

= slope length factor, a combination of slope grad ient and continuous extent 5

C

= cover and management factor, incorporating influ ences of crop sequence, residue 6 management, and tillage 7

P = practice factor, incorporating influences of con servation practices such as contouring or 8 terraces 9

Practice Effectiveness 10
Past reviews of the effectiveness of sediment contr ol measures have concluded that reduced 11 tillage systems reduce TP losses by 45 percent, TN losses by 55 percent, and sediment losses by 12 75 percent (USEPA 2003). 13
Harmel et al. (2006, 2008) have compiled measured annual N and P load data rep resenting field 14 scale transport from agricultural land uses. The 20 06 compilation includes included results from 15 40 scientifically peer-reviewed studies
, but draw s heavily from the 1980s. The more recent data 16 (2008 update) include 15 additional studies. In all , the database contains 1
, 677 watershed years 17 of data for various agricultural land uses and prac tices. Most data are from the 18 Southeast southeast and upper Midwest, with only one study, from the C hesapeake Bay Drainage 19

area. Table 2-17, Exhibit 1, below, provides a summary of median N and P loadin gs from Harmel 20 et al. (2006) from which N and P reductions could b e estimated. The current version can be 21 downloaded at http://www.ars.usda.gov/spa/manage-nutrient

. 22

Table 2-17 Exhibit 1 . Median N and P loadings (source Harmel et al. 2006). 23 Table 4. Median Annual Dissolved, Particulate, and Total N and P Load values (kg/ha) for Selected Treatments

Treatment* Total N (kg/ha) Dissolved N

(kg/ha) Particulate N

(kg/ha) Total P

(kg/ha) Dissolved P

(kg/ha) Particulate P

(kg/ha) Tillage Conventional 7.88a 2.41a 7.04a 1.05a 0.19b 0.64a Conservation 7.70a 2.30ac 3.40c 1.18ac 0.65ac 1.00a No-Till 1.32b 4.20c 1.80bc 0.63c 1.00c 0.80a Pasture/Range 0.97b 0.32b 0.62b 0.22b 0.15b 0.00b

Conservation Practice None 2.19a 1.60a 1.70a 0.41a 0.26ab 0.64ab One Practice 6.73b 1.33a 14.80a 0.61ab 0.14a 0.37a 2+ Practices 8.72b 2.61b 3.30a 1.22b 0.50b 0.75b

Soil Texture Clay 4.93a 4.47a 2.00a 0.92a 0.50a 0.55a Loam 4.05a 1.64b 5.78b 0.41b 0.18b 0.93a3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-65 Sand 2.74a 1.70ab –** 1.50ab 0.07ab –**
Source: Harmel et al. 2006 *For each nutrient form within a treatment, medians followed by a different letter are significantly d ifferent (a – 0.05). **No particulate N or P data were available for san dy soils.

1

2

3 In another literature review, Merriman et al. (2009 ) developed a compilation of BMP 4 effectiveness results. Table 2-18 Exhibit 2 presents a listing of individual results for conse rvation 5 tillage practices along with percent reductions for TP, TN
, and sediment. Additional data on 6 reductions for particulate P, dissolved P, NO 3 -N, and ammonium are also available. 73/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-66 Table 2-18 Exhibit 2 . TP, TN, and sediment Sediment reductions for various conservation tillage 1 practices as compiled by Merriman et al. (2009). 2 Reference (as

cited by Merriman et al. 2009) Reference (as cite d by Merriman et al. 2009) State BMP NAME Study Scale SLOPES HSG Total P % Total N

% Total Sediment % Zhu et al. 1989 Missouri Winter cover crop Field plot 0

- 3 D 92

Zhu et al. 1989 Missouri Winter cover crop Field plot 0

- 3 D 90

Zhu et al. 1989 M issouri Winter cover crop Field plot 0

- 3 D 92

Mutchler and McDowell, 1990 Mississippi Winter cover crop Field plot 3

- 8 C 72.3

Langdale et al. 1979 Georgia No

- till Small watershed 0

- 3 B 86

Langdale et al. 1979 Georgia No

- till Small watershed 0

- 3 C 86

McGregor and Greer, 1982 Mississippi No

- till Field 3

- 8 B 95.49

Berg et al. 1988 Oklahoma No

- till Small watershed 3

- 8 B 5 7.6 20.8
Mutchler et al. 1985 Mississippi No

- till Field plot 3

- 8 C 47

McDowell and McGregor, 1980 Mississippi No

- till Field plot 3

- 8 C 84 90 99

McGregor and Greer, 1982 Mississippi No

- till Field plot 3

- 8 C 95.49

Yoo et al. 1986 Alabama No

- till Field plot 3

- 8 B

- 2.76 54.44 Meyer et al. 1999 Mississippi No

- till Field plot 3

- 8 C 85.11 Meyer et al. 1999 Mississippi No

- till Field plot 3

- 8 C 90.84
Hairston et al. 1984 Mississippi No

- till Field plot 3

- 8 D 16.28

McGregor et al. 1975 Mississippi No

- till Field plot 3

- 8 B 85.71

McGregor et al. 1975 Mississippi No

- till Field plot 3

- 8 C 85.71

M utchler and Greer, 1984 State Mississip pi BMP

name No

till Study

scale Field plot SLOPES

3-8 HSG

C TP % TN % Total sediment % 94.08 Zhu et al. 1989 Mutchler and Greer, 1984 Missouri Mississi

ppi Winter

cover crop No-till Field plot 0

- 3

- 8 D C 92 % .7

Zhu Langdale et al. 1989 1979 Missouri Georgia Winter
cover crop No-till Field

plot Small watershed 0

- 3

- 8 D B 90% 86

Zhu Langdale et al. 1989 1979 Missouri Georgia Winter
cover crop No-till Field

plot Small watershed 0

- 3

- 8 D C 92% 863/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-67 Reference (as cited by Merriman et al. 2009) Reference (as cite d by Merriman et al. 2009) State BMP NAME Study Scale SLOPES HSG Total P % Total N

% Total Sediment % Mutchler and McDowell 1990 Dabney et al. 1993 Mississippi Winter
cover crop No-till Field plot 3-8 C 72.3% 56.76

Langdale Dabney et al. 1979 1993 Georgia Mississi

ppi No-till Small watershed Fiel d plot 0

- 3

- 8 B C 86% 50

Langdale Dabney et al. 1979 1993 Georgia Mississi

ppi No-till Small watershed Fiel d plot 0

- 3

- 8 C 86% 66.67

McGregor and Greer 1982 Dabney et al. 1993 Mississippi No-till Field plot 3-8 B C 95.49% 83.3 3

Berg Yoo et al. 1988 Oklahoma Alaba

ma No-till Small watershed Fiel d plot 3-8 B 22. 5 % 7.6% 23.8 20.8% 52.3

Mutchler et al. 1985 Schre iber and Cullum, 1998 Mississippi No-till Field plot Large watershed 3-8 C 76.52 67.68 47%

McDowell and McGregor 1980 Meyer et al. 1999 Mississippi No-till Field plot 3-8 C 84% 90% 99% 88.47

McGregor and Greer 1982 Mostaghimi, Dillaha, Shanholtz 1988 Mi ssissippi Virgin

ia No-till Field plot 3

- 8

- 15 C 97 95.49% 98

Yoo Mostaghimi et al. 1986 1992 Alabama Virginia No-till Field plot 3

- 8

- 15 B C 65.52

- 2.76% 90. 55 54.44% 69.4

7

Meyer Mostaghim i et al. 1999 1991 Mississippi Virgin

ia No-till Field plot 3

- 8

- 15 C 90.5 5 85.11% 94.7 5 Meyer Feagley et al. 1999 1992 Mississippi Louisi

ana No-till Field plot 3- 8 <N/A> C D 90.84% 74.2 5 Hairston et al. 1984 Daniels and Gilliam., 1996 Mississippi Virgin

ia No-till with

subsurface injection Field plot 3-8 D B 91 16.28% 92

McGregor Mostag himi et al. 1975 1991 Mississippi Virgin

ia No-till with

subsurface injection Field plot 3

- 8

- 15 B C 95.42 85.71%

McGregor et al. 1975 and Greer, 1982 Mississippi Notill Reduced Tillage Field plot 3-8 C 85.71% 91.8 4

Mutchler McGreg

or and Greer 1984 , 1982 Mississippi Notill Reduced Tillage Field plot 3-8 C B 94.08% 91.8 43/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-68 Reference (as cited by Merriman et al. 2009) Reference (as cite d by Merriman et al. 2009) State BMP NAME Study Scale SLOPES HSG Total P % Total N

% Total Sediment % Mutchler and Greer Hairston et al. 1984 Mississippi Notill Reduced Tillage Field plot 3-8 C D 92.7% 13.85

Langdale et al. 1979 Mutchler and Greer, 1984 Georgia Mississi

ppi Notill Reduced Tillage Small

watershed Fiel d plot 3-8 B C 86% 58.78

Langdale Truman et al. 1979 2003 Georgia Alabama No-till Cover crop (general) Small

watershed Fiel d plot 3-

8 <N/A> C B 86% 46

Dabney et al. 1993 Mississippi No-till Field plot 3-8 C 56.76%

Dabney et al. 1993 Mississippi No-till Field plot 3-8 C 50%

Dabney et al. 1993 Mississippi No-till Field plot 3-8 C 66.67%

Dabney et al. 1993 Mississippi No-till Field plot 3-8 C 83.33%

Yoo et al. 1988 Alabama No-till Field plot 3-8 B 22.5% 23.8% 52.3%
Schreiber and Cullum 1998 Mississippi No-till Large watershed 3-8 C 76.52 % 67.68%

Meyer et al. 1999 Mississippi No-till Field plot 3-8 C 88.47% Mostaghimi, Dillaha, Shanholtz 1988 Virginia No-till Field plot 8-15 C 97% 98%

Mostaghimi et al. 1992 Virginia No-till Field plot 8-15 C 65.52 % 90.55% 69.47%

Mostaghimi et al. 1991 Virginia No-till Field plot 8-15 C 90.55% 94.75%

Feagley et al. 1992 Louisiana No-till Field plot N/A D 74.25%

Daniels and Gilliam 1996 Virginia No-till with subsurface injection Field plot 3-8 B 91% 92%

Mostaghimi et al. 1991 Virginia No-till with subsurface injection Field plot 8-15 C 95.42%

McGregor and Greer 1982 Mississippi Reduced Tillage Field plot 3-8 C 91.84%

McGregor and Greer 1982 Mississippi Reduced Tillage Field plot 3-8 B 91.84%

Hairston et al. 1984 Mississippi Reduced Tillage Field plot 3-8 D 13.85%

Mutchler and Greer 1984 Mississippi Reduced Tillage Field plot 3-8 C 58.78%

Truman et al. 2003 Alabama Cover crop (general) Field plot N/A B 46%

Source: Merriman et al. 20093/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-69 Soil loss and ortho-P transport were measured from a conventional and two conservation tillage 1 treatments (zero and ridge tillage) from January 19 88 to September 1990 in southwestern 2 Ontario (Gaynor and Findlay 1995). Compared to conv entional tillage, conservation tillage 3 reduced average soil loss by 49 percent (899 kg/ha) and increased ortho-P concentrations in 4 runoff 2.2 times (0.25 mg/L). 5 Using a rain simulator on plots, Avalos et al. (200 7) found that corn straw residue decreased N 6 losses from 88.82 to 16.65 kg/ha (81 percent reduct ion) and decreased TP losses from 7.87 to 7 1.72 kg/ha (78 percent reduction). In another plot study using rainfall simulation, it was found 8 that under no-till conditions, plots with corn resi due and grass hedges averaged 52 percent less 9 runoff and 53 percent less soil loss than similar p lots without grass hedges (Gilley et al. 2000). 10 Under tilled conditions, the plots with corn residu e and grass hedges averaged 22 percent less 11 runoff and 57 percent less soil loss than comparabl e plots without grass hedges. The plots with 12 corn residue removed but with grass hedges present averaged 41 percent less runoff and 63 13 percent less soil loss than similar plots without g rass hedges. 14
One alternative to reduce compaction and restricted infiltration under long periods of no-till is 15 rotational tillage (Smith et al. 2007). In the firs t year of converting from long-term
, no-till to 16 rotational tillage on small plots that had been in a no-till corn-soybean rotation for 15 years, 17 runoff volumes and nutrient concentrations for NH 4 -N, NO 3 -N, and dissolved P (DP) were 18 greater from the no-till field. Before Prior to fertilization, no-till resulted in 83 g/ha greater NH4- 19 N and 32.4 g/ha greater dissolved P losses than rot ational tillage. After fertilization, no-till was 20 observed to lose 5.3 kg/ha more NH 4 -N, 1.3 kg/ha more NO 3 -N, and 2.4 kg/ha more dissolved P 21 than rotational tillage. 22
Conventional tillage, conservation tillage with cov er crop, and no-till with cover crop were 23 compared in a small grain-corn rotation in Austria in a field study from 1994 to

- 1999 (Klik et al. 24 2001). The field plots ranged from 3 to

- 4 m in width and 15

- m long, and slope ranged from 6 to 25

- 16 percent. Runoff was not statistically different among the practices, but nutrient losses from 26 April to October were 13.7 kg/ha for conventional t illage, 9.1 kg/ha (34 percent decrease) for 27 conservation tillage, and 7.7 kg/ha (44 percent dec rease) for no-till. P Phosphorus losses were 6.5, 28 3.1 (52 percent decrease), and 2.0 kg/ha (69 percen t decrease), respectively. In a 9-year field 29 study in Finland, Puustinen et al. (2005) found tha t traditional cultivation treatments produced 30 the highest TSS concentrations (1.38 and 1. 18 mg/L , respectively), whereas values between 0.44 31 and 0.53 mg/L were measured for three treatments with reduced (or no) tillage. Particle-bound P 32 concentrations closely followed those of TSS, but DR d issolved reactive P showed contrasting 33 behavior. 34
Finish researchers (Turtola et al. 2007) found that the frequency of tillage, rather than the depth 35 of tillage, has a greater effect on erosion on clay ey soils. Shallow autumn tillage produced 36 erosion as high as mouldboard ploughing (407

– - 1700 kg/ha-yr), but 48 percent and 12 percent 37 lower erosion levels were measured from plots left untilled in autumn, covered by grass or barley 38 residues, respectively. In a companion study, Uusit alo et al. (2007) found that stubble treatment 39 yielded higher dissolved reactive P ( DRP ) losses (104

– - 259 g/ha-yr) than autumn ploughing (77

– 40

- 96 g/ha-yr), and equally high particulate P (PP) lo sses (mean 660, 235

– - 1
, 300 g/ha-yr). Shallow 41 autumn tillage produced 28 percent higher DRP losse s (mean 120, 107

– - 136 g/ha-yr) than 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-70 ploughing (83

– - 117 g/ha-yr) and 11 percent higher PP losses (mean 1
, 090, 686

– - 1
, 336 g/ha-yr) 1 than ploughing (783

– - 1253 g/ha-yr). 2

Practice Costs 3 In an analysis of various combinations of practices to control sediment loss in a 12

- ha 4 subwatershed of the Mississippi Delta Management Sy stem Evaluation Area using the 5 Annualized Agricultural Nonpoint Source pollutant l oading model (AnnAGNPS 2.1), it was 6 found that the most cost-effective practices were m anagement of volunteer winter weeds as 7 cover crops and various types of edge-of-field, gra de-control pipes (Yuan et al. 2002; Dabney et 8 al. 2001). The average marginal cost using practice s for sediment yield reduction was about 9 $10/MT (2008 dollars/metric ton) for conventional a nd reduced tillage. The cost was higher, 10 about $13/MT for no-till because the practice of no -till alone reduced sediment yield by half, and 11 further marginal reductions were more expensive. 12
Using the Water Erosion Prediction Project (WEPP) model calibrated to a 6.4-ha site within Four 13 Mile Creek watershed in eastern Iowa, Zhou et al. ( 2009) compare the cost of lost soil for chisel 14 plow, disk tillage, and no-tillage. The value of lo st soil resulting from soil erosion ranged 15 between $10.9 and $137.3/ha-yr for the simulated sc enarios in the study when a soil value of 16 $6.1/t was considered. When factoring in the value of soil, no-tillage was the most efficient 17 practice with the highest net benefit of $94.5/ha-y r. 18
Using the Raritan Basin in New Jersey, Qiu et al. ( 2009) compare the placement of fixed-width 19 buffers based on regulatory rules, variable-width b uffers based on watershed initiatives, and 20 variable source area-based conservation buffer plac ement strategy derived from an alternative 21 concept of watershed hydrology. The variable source area-based conservation buffer placement 22 strategy targets the most hydrologically critical s ource areas in a watershed tier buffer placement. 23 The authors show that there is little difference in cost effectiveness between fixed- and variable24 width buffers
, but that the variable source area-based buffer pla cement strategy is more cost

25 effective. 26

Both national and selected state costs for a number of common erosion control practices are 27 presented in Table 2- 19 1 7 . The variability in costs for practices can be acc ounted for primarily 28 through differences in site-specific applications a nd costs, differences in the reporting units used, 29 and differences in the interpretation of reporting units. 30

The cost estimates for control of erosion and sedim ent transport from agricultural lands in Table 31 2- 20 18 are based on experiences in the Chesapeake Bay Pro gram. 32
Practice Savings 33 It is important to note that for some practices, su ch as conservation tillage, the net costs often 34 approach zero and in some cases can be negative bec ause of the savings in labor and energy. In 35 fact, it is reported that cotton growers can lower their cost per acre by $24.32 because of due to 36 lower fixed costs associated with conservation till age (Zeneca
, 1994). 37

Table 2- 19 17 . Representative costs of selected erosion control practices

. 38

Practice Unit Range of capital costs a costs 1 References3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-71 Diversions ft $ 1.97– $ 5.51 Sanders et al. 1991 Smolen and Humenik

, 1989
Terraces ft

a.s. b 2 $ 3.32– $ 14.79

$ 24.15– $ 66.77 Smolen and Humenik

, 1989

Russell and Christiansen

, 1984 Waterways ft

ac

a.e. c 3 $ 5.88– $ 8.87

$ 113– $ 4
, 257 $ 1250– $ 2
, 174 Sanders et al. 1991

Barbarika
, 1987; NCAES

, 1982; Smolen and Humenik
, 1989 Russell and Christiansen

, 1984
Permanent Vegetative Cover ac $ 69– $ 270 Barbarika
, 1987; Russell and Christiansen

, 1984; Sanders et al. 1991; Smolen and Humenik

, 1989 Conservation Tillage ac $ 9.50– $ 63.35 NCAES

, 1982; Russell and Christiansen

, 1984; Smolen and Humenik

, 1989

Notes:

a. 1 Reported costs inflated to 1998 dollars by the rat io of indices of prices paid by farmers for all pro duction items, 1991 = = 100. b. 2 acre served
c. 3 acre established [Note: 1991 dollars from CZARA were adjusted by +15 %, based on ratio of 1998 Prices Paid by Farmers/19 91 Prices Paid by Farmers, according to USDA National Agricul tural Statistics Service, http://www.usda.gov/nass/sources.htm http://www.usda.gov/nass/ sources.htm , 28 September

, 1998] 1

Table 2- 20 18 . Annualized cost estimates and life spans for sele cted management practices from 2 Chesapeake Bay installations a Installations a (Camacho, 1991). 3

Practice Practice life span Median annual costs b (Years) (eac c ) ($/acre/yr) Nutrient Management 3 2.40 Strip-cropping 5 11.60
Terraces 10 84.53 Diversions 10 52.09 Sediment Retention Water Control Structures 10 89.22 Grassed Filter Strips 5 7.31 Cover Crops 1 10.00 Permanent Vegetative Cover on Critical Areas 5 70.70 Conservation Tillage d 1 17.34 Reforestation of Crop and Pastured 10 46.66 Grassed Waterways e 10 1.00/LF/yr Animal Waste System f 10 3.76/ton/yr

Source: Camacho 1991

Notes:

a

. Median costs (1990 dollars) obtained from the Ches apeake Bay Program Office (CBPO) BMP tracking data base and Chesapeake Bay Agreement Juristictions’ un it data cost. Costs per acre are for acres benefite d by the practice. b

. Annualized BMP total cost including O&M, planning, and technical assistance costs.
c

. EAC = equivalent Equivalent annual cost: annualized total; costs for the life span. Interest rate = 10%.3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-72 d

. Government incentive costs.
e

. Annualized unit cost per linear foot of constructe d waterway. f

. Units for animal waste are given as $/ton of manur e treated.
1



### 3.3 Cover Crops 2
Implementation Measure: Use the most suitable cover crops for the site on all acres that have received any manure or chemical fertilizer applicat ion. Cover crops should be used during a nongrowing season (including winters) or when there is bare land in a field.
Implementation Measure : Use the most suitable cover crops for the site on a ll acres that 3 have received any manure or chemical fertilizer application. Cover crops should be used 4 during a non

- growing season (including winters), or when there i s bare land in a field

. 5
Cover crops, also called catch crops or relay crops , are grasses, legumes and forbs used for 6 seasonal cover and other conservation purposes. Cov er crops provide those lands in active or 7 fallow production a rooted plant to take in residua l or excess nutrients as well as hold the soil in 8 place, thus extending the growing season. They can be incorporated into bare earthen rows 9 during a cropping season for corn, vegetables and m any other row crops grown in the 10 Chesapeake Bay. They can also be an excellent stabi lizer during the non-growing season across 11 the entire expanse of field. By extending the growing season, excess nutr ients are taken up as 12 well as additional water, thus lessening the need f or intensive drainage. Cover crops provide a 13 cover to the soil
, and provide a host of benefits to water quality. 14
Cover crops include living mulches, winter cover cr ops and perennials. Living mulches are 15 planted before prior to or during the main row crop planting
, and are maintained throughout the 16 growing season. They These can be perennial species with annual maintenance. The living mulch 17 is not meant to take nutrients away from the main r ow crop ; , rather
, the producer should plant a 18 species that is suppressed during the intensive gro wth period of the main crop and is taking in 19 excess available nutrients and is growing as the ma in row crop matures or after it is harvested. 20 However, in growing such these crops in tandem, the living mulch will compete to a degree with 21 the main row crop for both water and nutrient uptak e. Both perennial legumes and grasses are 22 options as living mulches. Perennials are row crops planted once and intended to stay in place 23 over multiple years. 24
In general, a cover crop is planted shortly before or soon after the main row crop is harvested . It 25 is then , and killed or removed before or soon after planting of the subsequent season’s main row 26 crop. The cover crop remains on the field through t he winter and is harvested or plowed under in 27 the spring before prior to planting. As described in NRCS Conservation Practice Standard code 28 340, cover crops can may be used on any land where vegetative cover is need ed for natural 29 resource protection or improvement. Cover crops might may be beneficial for controlling 30 nonpoint source pollution where they are used to do the following : 31

• Reduce erosion from wind and water which can carry nutrients and sediments to surface 32 waters 333/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-73 • Capture and recycle or redistribute nutrients in th e soil profile to reduce nutrient 1 availability to be transported from agricultural la nds through runoff or leaching 2

• Promote biological N nitrogen fixation through use of leguminous cover crops to reduce 3 the need for addition of N nitrogen fertilizer to subsequent crops 4

• Minimize and reduce soil compaction, thereby improv ing infiltration and reducing the 5 rate and volume of runoff from agricultural lands

. 6
The Midwest Cover Crop Council Web site ( www.mccc.msu.edu/CCinfo/cropbycrop.html ) 7 provides information on the variety of options for planting cover crops, and describes the plant 8 species that are grasses, legumes, brassicas, and o ther non-legume broad

- leafed plants. 9

Practice Effectiveness 10
Nutrient Reduction 11 Staver and Brinsfield (1998) investigated the effec ts of cereal grain winter cover crops on nitrate 12 leaching rates, profile nitrate storage, and nitrat e concentrations in shallow groundwater in two 13 field-scale watersheds planted continuously in corn ( Zea mays L .) from 1984 through 1996. Rye 14 winter cover crops planted after corn harvest consi stently reduced nitrate-N concentrations in 15 root zone leachate to less than 1 mg/L during most of the groundwater recharge period
, and 16 reduced annual nitrate leaching losses by approxima tely 80 percent relative to winter-fallow 17 treatments. Shallow groundwater nitrate-N concentra tions under long-term continuous corn 18 production decreased from the 10 to 20 mg/L range t o less than 5 mg/L after 7 seven years of 19 cover crop use. 20
A 3-year field experiment was conducted on sandy lo am soils in southwestern Michigan to 21 investigate the combined effects of N fertilization rates and rye cover crops on NO 3 leaching in 22 inbred maize fields (Rasse et al. 2000). Annual NO 3 leaching losses to ground water fertilized at 23 202 kg N/ha averaged 88 kg NO 3 -N/ha, but rye interseeded with inbred maize fertil ized at 202 24 kg N/ha sequestered from 46 to 56 kg/ha of excess f ertilizer N. Well-established rye cover crops 25 reduced NO 3 leaching by as much as 65 kg N/ha when the previou s crop was fertilized with 202 26 kg N/ha, but rye scavenged little residual fertiliz er N in plots fertilized at 101 kg N/ha. 27
In Iowa, Singer et al. (2008) measured the effects of winter small-grain cover crops (CC) and 28 subsequent liquid manure injection (N rates of 112, 224, and 336 kg N/ha) on nutrient uptake and 29 corn yield. Although fall (but not spring) CC dry m atter (DM) was 26 percent lower with manure 30 than without manure, no difference was detected for N (9.4 kg/ha) or P (1.4 kg/ha) uptake. Shoot 31 dry matter ( DM ) and N, P, and K uptake increased 29, 41, 31, and 2 5 percent
, respectively
, from 32 the CC manure 112 kg N/ha treatment to the CC manur e 224 kg N/ha treatment, with no increase 33 above the CC manure 224 kg N/ha treatment. Cover cr op N, P, and K uptake were all higher in 34 CC manure versus vs. no manure (60.1 versus vs. 35.6 kg/ha, 9.2 versus vs. 6.6 kg P/ha and 41.3 35

versus vs. 30.0 kg K/ha, respectively), while corn yield was unaffected by CC and responded 36 positively to manure application (11,022 with manur e versus vs. 9,845 kg/ha without manure). 37
In a field study to determine the potential of a Bermuda bermuda grass/ryegrass combination to 38 reduce the level of Mehlich 3 P that had accumulate d in a Savannah soil from broiler litter 39 application over 30 years, coupled with antecedent litter rates of 0, 4.48, 8.96, 17.9, and 35.8 40 Mg/ha, Read et al. (2009) it was found that annual DM yield and P uptake generally increased as 413/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-74 litter rate increased up to 17.9 Mg/ha (Read et al. 2009) . Analysis of Mehlich 3 P in surface soil 1 (0

– - 15 cm depth) at four sampling dates over 19 months showed reductions of 25, 27, 22, 26, 2 and 29 percent at the five antecedent litter rates, respectively. Ryegrass- Bermuda bermuda grass 3 significantly increased DM yield and P uptake
, but did not increase reductions in Mehlich 3 P, as 4 compared to Bermuda bermuda grass winter fallow, and both forage systems remove d about 49 5 kg/ha P and reduced Mehlich 3 P by about 26 mg/kg a nnually via five harvests per year. 6
Sharma and Sahi (2005) examined the phytoremediatio n potential of Gulf and Marshall ryegrass 7 grown in a greenhouse under varying conditions of s oil P concentration, pH, and temperature, 8 finding that an increase in plant biomass was propo rtional to the increasing concentrations of P 9 up to a level of 10 g of P/kg of soil. Significant effects of both soil pH and temperature on plant 10 uptake of P were measured, and the researchers conc luded that Gulf and Marshall ryegrass can 11 accumulate high P under optimal conditions and thus reduce soil P concentrations in successive 12 cropping. 13

Sediment Reduction 14 A 2-year study comparing sediment, N, and P runoff losses for cotton managed with winter 15 fallow and conventional tillage versus cotton manag ed with a winter wheat cover crop and strip16 tillage, found that the cover crop/strip-till treat ment reduced sediment loss for all sampling dates, 17 especially in 2000 when sediment losses were less t han half of those with conventional tillage. 18 Sediment loss was also reduced with cover crop/stri p-till during the early growing season, before 19 crop canopy closure, and vegetative field borders further reduced runoff of sediment and sedi20 ment-attached P (Hoyt 2005). 21
Van Vliet et al. (2002) compared different fall-man ure application strategies on runoff and 22 contaminant transport from silage corn land in the Lower Fraser Valley of British Columbia. The 23 treatments were a control that did not receive manu re in the fall, manure broadcast in the fall on 24 corn stubble, and manure broadcast in the fall on c orn stubble with an established relay crop. 25 Runoff, solids, and nutrients loads from natural pr ecipitation were measured on replicated 26 experimental plots (0.0125 ha) from 1996 to 1998. F all-applied manure on 3

– - 5 percent sloping 27 silage cornland without a relay crop yielded high s uspended solids loads of between 7 and 14 28 Mg/ha/yr and high nutrient transport with mean annu al total Kjeldahl N ( TKN
, ) P, and K loads 29 of 98, 21, and 63 kg/ha respectively. Compared with no relay crop, intercropping silage corn 30 with a relay crop of Italian ryegrass reduced the m ean annual runoff and suspended solid load by 31 53 and 74 percent, respectively, TKN load by 56 per cent, P load by 42 percent, K load by 31 32 percent, and Cu load by 57 percent. Even though tot al nutrient loads were lower with the relay 33 crop treatment, all fall manure treatments includin g the relay crop resulted in nutrient loads 34 above local guidelines for the first three runoff e vents immediately following application. 35

Practice Costs 36 The Chesapeake Bay Commission (2004) evaluated 34 n utrient and sediment

- reduction 37 practices representing a wide range of specific act ions associated with wastewater treatment 38 plants, agriculture, urban stormwater, land preserv ation, forestry
, and air pollution. The analysis 39 resulted in identifying identification of six measures that could achieve a substantial porti on of 40 the N, P, nitrogen, phosphorus and sediment

- reduction goals set for the period 2002–20010 in 41 the Chesapeake 2000 agreement. One of those practic es is enhanced adoption of late cover crops 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-75 and use of early cover crops to absorb excess nutri ents in the soil. The report estimates that 1 implementing implementation of fall cover crops at the maximum extent feasible (2. 05 million 2 acres) in the watershed could achieve annual N nitrogen reductions of 15.2 million pounds of 3 N nitrogen at $3.50 per pound

, and 0.22 million pounds of P, phosphorus and 0.11 million tons of 4 sediment at no additional cost. Maximum feasible im plementation of early cover crops could 5 provide annual reductions of 8.1 million pound of N nitrogen at $2.33 per pound and 0.22 million 6 pounds of P phosphorus and 0.11 million tons of sediment at no additional cost. 7

Saleh
, et al. (2005) used the modified SWAT (SWAT-M) and FEM (Farm-level Economic 8 Model) models to evaluate the environmental and eco nomic impacts of various BMP scenarios 9 often adopted by local farmers to reduce sediment a nd nutrient loadings (in particular NO 3 -N). 10 Measured values of water quality indicators from th e Walnut Creek watershed (WCW) located in 11 central Iowa were used to verify the capability of SWAT-M to predict the impact of late-spring 12 nitrate test (LSNT) and rye cover crop management o n NO 3 -N reduction at the subbasin level. 13 The results obtained from SWAT-M simulation results , similar to field measurement data, 14 indicated a 25 percent reduction in NO 3 -N under the LSNT scenario. FEM results indicated a 15 corresponding increased annual cost of $6/ha across all farms in the watershed. Simulating 16 Simulation of other scenarios, including winter cover cropping an d a combination of LSNT and 17 cover cropping at different adoption rates within W CW, resulted in a progressive reduction in 18 sediment and nutrient losses as adoption rates incr eased. Using Use of the rye cover crop added 19 about $25/ha to $35/ha to the annual cost of the av erage farm, indicating that some cost-share 20 support might may be necessary to encourage farmers to use winter co ver crops. 21
In an application of the Annualized Agricultural No npoint Source pollutant loading model 22 (AnnAGNPS 2.1) to a 12-ha Mississippi Delta Managem ent System Evaluation Area 23 (MDMSEA) subwatershed, cover crops, filter strips, grade control pipes, and impoundments 24 were modeled in combination with three tillage syst ems: conventional tillage, reduced tillage, 25 and no-till (Yuan
, et al. 2002). Costs of BMPs were estimated using 2 001 state average prices for 26 Mississippi, and amortized fixed costs

— , using a 25-year planning horizon and interest rates of 27 both 5 percent and 10 percent

— , were combined with direct annual costs into total a nnual cost 28 estimates. AnnAGNPS predicted that no-till alone, r educed tillage with winter cover and an 29 edge-of-field pipe, or conventional tillage with a small permanent impoundment (covering less 30 than 3 percent of the watershed) would all reduce s ediment yield by at least 50 percent. The most 31 cost-effective BMPs were managing management of volunteer winter weeds as cover crops and 32 various types of edge-of-field grade-control pipes. The average marginal cost using BMPs for 33 sediment yield reduction was about $8/MT ($7.3/t) f or conventional and reduced tillage. The 34 cost was higher, about $10.7/MT, ($9.7/t) for no-ti ll because the practice of no-till alone reduced 35 sediment yield by half, and further marginal reduct ions were more expensive. 36
In an assessment of options to address nitrate prob lems in the Neuse River Basin of North 37 Carolina, it was concluded that cover crops can red uce N nitrogen loading of shallow 38 groundwater by 5 to 15 percent (Wossink 2001). Cons ervation tillage, including cover crops, is 39 identified as one of the three best options for N nitrogen reduction in the Piedmont region, and 40 the cost of a wheat cover crop is estimated at $76/ acre with $0 in net receipts, for a net revenue 41 of -$76/acre. 42
Franzluebbers (2005) summarizes research on some of the key components that could produce 43 viable integrated crop-livestock production systems in the Southeast: sod-based crop rotation, 443/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-76 cover cropping, intercropping, and conservation til lage. Despite its agronomic benefits, 1 adopting the adoption of cover cropping appears to be limited because of co st without immediate 2 economic benefit, but the author suggests that graz ing of cover crops could provide such an 3 immediate economic benefit to producers. On the basis of Based on the research reviewed, 4 barriers to adopting adoption of integrated crop–livestock systems include lack of experience or 5 time to manage both the crops and livestock. Severa l studies regarding economic returns from 6 grazing livestock were reviewed
, and Franzluebbers found the following: 7

• Livestock increased labor required on an average No rth Dakota farm by about 50 percent, 8 but only about 30 percent of the additional time co mpeted directly during critical crop 9 management. Net economic return attributed to lives tock increased whole farm income 10 by about 20 percent. 11

• Ten steers and heifers were grazed on a 4-ha area o f rye or ryegrass cover crop at the 12 Sunbelt Agricultural Exposition near Moultrie, Georgia GA . The equivalent of $311 13
± $ 62/ha greater gross income was generated in the val ue of animal gain (assuming 14 $1.75/kg animal gain). 15

• A 3-year experiment was conducted at Headland, Alabama AL , to compare the effect of 16 oat and ryegrass winter cover crops under cattle gr azing on cotton and peanut production 17 managed under different tillage systems. Net return from winter grazing of cover crops (5 18 head/ha for 80 d) was $185 to $ 200/ha/yr. 19

• Using an economic model comparing a conventional sy stem (53 ha cotton, 27 ha peanut) 20 with a sod-based rotation system (20 ha cotton, 20 ha peanut, 40 ha bahiagrass) on a 21 typical small farm in Florida, net profit was expec ted to be $15,689/ year yr on a 22 conventional farm and $44,840/ year yr on a sod-based farm with cattle grazing the 23 second 2nd year bahiagrass. 24



### 3.4 Pasture Land Management 25
Implementation Measure: Minimize nutrient and soil loss from pasture land by maintaining uniform livestock distribution over the pasture, ke eping livestock away from riparian areas, and managing stocking rates and vegetation to prevent p ollutant losses through erosion and runoff.
Implementation measure : Minimize nutrient and soil loss from pasture land by 26 maintaining uniform livestock distribution over the pasture , keeping livestock away from 27 riparian areas , and managing stocking rates and vegetation to prevent pollutant losses 28 through erosion and runoff

. 29 In addressing nonpoint source pollution concerns, p roducers should must balance production and 30 water quality objectives. This section explores som e of the production-oriented resources 31 management decisions confronting livestock producer s. 32
Livestock can obtain their needed nutrients through feed supplied to them in a confined livestock 33 facility, through forage, or through a combination of forage and feed supplements. Forage 34 systems can be pasture-based or rangeland-based. 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-77 It is important for the reader to be aware of the d ifference between rangeland and pasture. 1 Rangeland refers to those lands on which the native or introd uced vegetation (climax or natural 2 potential plant community) is predominantly grasses , grasslike plants, forbs, or shrubs suitable 3 for grazing or browsing. Rangeland includes natural grassland, savannas, many wetlands, some 4 deserts, tundra, and certain forb and shrub communi ties. Pastures are those improved lands that 5 have been seeded, irrigated, and fertilized and are primarily used for producing the production of 6 adapted, domesticated forage plants for livestock. Other grazing lands include grazable forests, 7 native pastures, and crop lands producing forage. 8
The major differences between rangeland and pasture are the kind of vegetation and level of 9 management that each land area receives. In most ca ses, range supports native vegetation that is 10 extensively managed through the control of livestoc k rather than by agronomy practices, such as 11 fertilization, mowing, or irrigation. Rangeland als o includes areas that have been seeded with 12 introduced species (e.g., clover or crested wheatgr ass) but are managed with the same methods 13 as native range. For both rangeland and pasture, th e key to good grazing practice is vegetative 14 management, i.e., timing of grazing should be manag ed to ensure adequate vegetative regrowth 15 and soil stability. 16
Pastures are represented by those lands that have b een seeded, usually with introduced species 17 (e.g., legumes or tall fescue) or in some cases wit h native plants (e.g., switchgrass or needle 18 grass), and that which are intensively managed using agronomy practices a nd control of livestock. 19 Permanent pastures are typically based on perennial
, warm-season (e.g., Bermuda bermuda grass) 20 or cool-season (e.g., tall fescue) grasses and legu mes (e.g., warm-season alfalfa, cool-season red 21 clover), while temporary pastures are generally plo wed and seeded each year with annual 22 legumes (e.g., warm-season lespedezas, cool-season crimson clover) and grasses such as warm23 season pearl millet and cool-season rye (Johnson et al. 1997). Plants Plant selection for pastures 24 should selected on the basis be based upon consideration of climate, soil type, soil condition, 25 drainage, livestock type and expected forage intake rates, and the type of pasture management to 26 be used. Management of pH and soil fertility is ess ential to both establishing the establishment 27 and maintaining maintenance of pastures (Johnson et al. 1997). In some climates (e .g., Georgia), 28 overseeding of summer perennials with winter annual s is done to provide adequate forage for the 29 period from mid-winter to the following summer. 30
Approaches to reducing pollutant runoff from pastur e land address managing animal stocking 31 rates and maintaining vigorous vegetation to provid e for soil stability and nutrient recycling. 32 Based on a review of the literature, Osmond et al. (2007) recommend recommended that practices 33 should be used that encourage more uniform livestock distr ibution over the pasture; riparian 34 areas should not be used as shade paddocks, holding areas, or feeding areas; and access to 35 riparian areas should be limited and should not occ ur when soils are wet or boggy
, and when 36 acceptable forage is available on non-riparian site s within the same grazing unit. Good pasture 37 management maintains stocking rates and vegetation to prevent pollutant losses through erosion 38 and runoff; silvopasture techniques integrate trees into pastures to improve nutrient uptake and 39 vegetation stability. A discussion of forestry prac tices and methodologies that can be 40 incorporated into silvopasture are can be found in Chapter 4. 41

Practice Effectiveness 42 Pasture management 433/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-78 In a Georgia plot study, Butler et al (2008b) compa red runoff and sediment and nutrient export 1 from poorly drained and well

- drained riparian soils where heavy or light grazing pressure by 2 cattle was simulated. Runoff volume was generally g reater from heavily grazed areas than from 3 lightly grazed areas. Light-use plots were effectiv e at minimizing export of TSS on both soils 4 (< 30 kg/ha). Mean TP total P export was fourfold greater from heavy-use plots t han from light5 use plots on both soils. While export of nitrate-ni trogen (NO 3 -N) was unaffected by grazing 6 pressure and soil drainage, mean ammonium-nitrogen (NH 4 -N) and T total N export from poorly 7 drained heavy-use plots was greater than fivefold t hat from well-drained light-use plots. Results 8 indicate that livestock heavy-use areas in the ripa rian zone can may export substantial TSS and 9 nutrients, especially on poorly drained soils. Howe ver, when full ground cover is maintained on 10 well-drained soils, TSS and nutrient losses can may be limited. 11
Sistani et al. (2008) investigated the effect impact of pasture management and broiler litter 12 application rate on nutrient runoff from Bermuda bermuda grass pasture plots in Kentucky. 13 Runoff was 29 percent greater from grazed than haye d pastures regardless of the litter 14 application rate. There was greater inorganic N in the runoff from grazed paddocks when litter 15 rate was based on N rather than P. The mean TP total P loss per runoff event for all treatments 16 ranged from 7 to 45 g/ha and the grazed treatment w ith litter applied on N basis had the greatest 17 T total P loss. The SR soluble reactive P was greater for treatments with litter applied on N basis 18 regardless of pasture management. Litter can may be applied on an N

- basis if the pasture is 19 hayed and the soil P is low. In contrast, litter ra tes should be based on a P-basis if pasture is 20 grazed. 21
Introduction of cattle to consume the cover crop fo rage in Georgia did not cause substantial 22 damage to the soil (Franzluebbers and Stuedemann 20 08). Grazing of cover crops had little 23 effect on soil bulk density. Stability of macroaggr egates in water was unaffected by grazing of 24 cover crops. There was a slight tendency for water infiltration rate to be lower with grazing of 25 cover crops (5.6 mm/min) than when ungrazed (6.9 mm /min),). 26
In New Zealand, McDowell and Houlbrooke (2009) asse ssed restricted grazing and applying the 27 application of aluminum sulfate for their potential to decrease co ntaminant loss from winter 28 grazing of forage crops. Volumes of surface runoff and loss of P and sediment showed 29 significant differences between the control treatme nts (i.e.
, no mitigation) with cattle crop (88 30 mm surface runoff) greater than > sheep crop (67 mm) greater than > sheep pasture (33 mm). 31 Restricted winter grazing and alum application afte r grazing significantly decreased P losses in 32 surface runoff under cattle (from 1.4 to 0.9 kg P/h a, 36 percent) and sheep (from 1.0 to 0.7 33 kg/P/ha, 30 percent). In cattle

- grazed plots, restricted grazing also decreased sus pended 34 sediments by 60 percent. 35
Owens and Shipitalo (2009) evaluated two systems of over-wintering cattle in Ohio. Vegetative 36 cover in the continuous wintering area frequently d ecreased to less than 50 percent by late 37 winter/early spring while it remained at or near 10 0 percent in the rotational system. Annual 38 runoff from the rotational wintering system was 69 percent lower than from the continuous 39 wintering system; sediment loss was also reduced by 91 percent under the rotational system 40 compared to continuous wintering. Surface runoff lo sses of N from the continuous system were 41 double those from the rotational system during the dormant season. Some of the these differences 42 could be attributed to higher cattle occupancy rate in the continuous wintering system. 433/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-79 In North Carolina, Butler et al. (2007) reported th at mean nitrate N export from bare ground plots 1 was greatest from bare ground and was reduced by 31 percent at 45 percent cover. Mean T total 2 N export was greatest from bare ground and was redu ced by at least 85 percent at cover levels 3 from 45 to 95 percent. Whereas site did not affect impact N export, results indicate indicated that 4 cover and time of rainfall following manure deposit ion are important determinants of the 5 effect impact of riparian grazing. 6
In a review of experimental data from the Northeast United States northeast U.S. , Stout et al. 7 (2000) assessed the relationships between stocking rate and NO 3 -N leaching losses beneath an 8 intensively grazed pasture. A relatively low cumula tive seasonal stocking rate of about 200 9 mature Holstein/ha could result in a 10 mg / / NO 3 -N concentration in the leachate beneath a 10 fertilized, intensively grazed pasture. That This means that while management intensive grazing 11 can improve farm profitability and help control ero sion, it can have a significant negative effect 12 on water quality beneath pastures 13
Lyons et al. (2000) compared bank erosion, fish hab itat characteristics, trout abundance, and a 14 fish-based index of biotic integrity (IBI) among st ations with riparian continuous grazing, 15 intensive rotational grazing, grassy buffers, or wo ody buffers along 23 trout stream reaches in 16 Wisconsin. After statistically factoring out waters hed effects, stations with intensive rotational 17 grazing or grassy buffers had the least bank erosio n and fine substrate in the channel. Continuous 18 grazing stations had significantly more erosion and , with woody buffers, more fine substrate. 19 Station riparian land use had no significant effect on width/depth ratio, cover, percent pools, 20 habitat quality index, trout abundance, or IBI scor e. 21
From Minnesota, Magner et al. (2008) report r eported that low IBI scores are were associated 22 with streams draining continuously grazed pasture, while higher IBM scores occur occurred on 23 nongrazed sites. Nongrazed sites were associated wi th reduced soil compaction and higher bank 24 stability, whereas continuously grazed sites show showed increased soil compaction and lower 25 bank stability. Short-duration grazing sites are were intermediate. 263/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-80 Table 2- 21 19 . Summary of reported practice effects resulting fr om pasture management

. 1

Location Study

type Practice Practice effects Source GA Plots Stocking rate Runoff volume was greater from heavy

- use than from light

- use. Light-use plots were effective at minimizing export of TSS. Mean T total P export was fourfold greater from heavy-use plots than from light-use plots. While export of nitrate

nitrogen ( NO 3 -N ) was unaffected by grazing pressure and soil drainage, mean ammonium

nitrogen ( NH 4 -N ) and T total N export from poorly drained heavy-use plots was greater than fivefold that from well-drained light-use plots. Butler et al

. 2008b

KY Plots Pasture

management, litter application rate Runoff was 29% greater from grazed than hayed

pastures regardless of litter application rate. There was greater inorganic N in the runoff from grazed paddocks when litter rate was based on N rather than P. The mean T total P loss per runoff event for all treatments ranged from 7 to 45 g/ha and the grazed treatment with litter applied on N basis had the greatest T total P loss. Sistani et al. 2008

GA Field Grazing cover

crops Grazing of cover crops had little effect on soil

bulk density; stability of macroaggregates in water was unaffected by grazing of cover crops. Franzluebbers & Stuedemann 2008 New Zealand Field Restricted

grazing, alum Restricted winter grazing and alum application

after grazing significantly decreased P losses in surface runoff under cattle (from 1.4 to 0.9 kg P/ha, 36%) and sheep (from 1.0 to 0.7 kg/P/ha, 30%). In cattle grazed plots, restricted grazing also decreased suspended sediments by 60%. McDowell and Houlbrooke 2009

OH Field Cattle

wintering systems Annual runoff from the rotational wintering system

was 69% lower than from the continuous wintering system; sediment loss was also reduced by 91% under the rotational system vs. continuous wintering. Surface runoff losses of N from the continuous system were double those from the rotational system during the dormant
season. a 1 Owens and Shipitalo 2009

NC Plots Vegetative

cover Mean nitrate N export from bare ground plots was

greatest from bare ground and was reduced by 31% at 45% cover. Mean T total N export was greatest from bare ground and was reduced by at least 85% at cover levels from 45–95%. Butler et al. 2007

Northeast U.S. Review Intensive

grazing A relatively low cumulative seasonal stocking rate

of about 200 mature Holstein/ha could result in a 10 mg / / NO 3 -N concentration in the leachate beneath a fertilized, intensively grazed pasture. Stout et al. 20003/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-81 Location Study

type Practice Practice effects Source WI Field Rotational

grazing Stations with intensive rotational grazing or

grassy buffers had the least bank erosion and fine substrate in the channel. Continuous grazing stations had significantly more erosion and more fine substrate. Station riparian land use had no significant effect on width/depth ratio, cover, percent pools, habitat quality index, trout abundance, or IBI score. Lyons et al. 2000

MN Field Short-duration

grazing Low IBI scores associated with streams draining

continuously grazed pasture; higher IBM scores occurred on nongrazed sites. Nongrazed sites associated with reduced soil compaction and higher bank stability; continuously grazed sites showed increased soil compaction and lower bank stability. Short-duration grazing sites were intermediate. Magner et al. (2008

Notes:

a. Footnotes:

1 Some of the these differences could be attributed to higher cattle o ccupancy rate in the continuous wintering system

Silvopasture 1 In Missouri, Garrett et al. (2004) reported that ma ny cool-season forages benefit from 40 percent 2 to 60 percent shade, and grazing trials in such con ditions have proven to be successful. Also in 3 Missouri, Kallenbach et al. (2006) reported that cu mulative forage production in annual 4 ryegrass/cereal rye planted into a 6- to 7-year-old forested stand was reduced by approximately 5 20 percent compared to the same forages planted in open pasture. However, beef heifer average 6 daily gain and gain/ha were equal for both treatmen ts, suggesting that a silvopasture system 7 likely would not sacrifice livestock production in the this system. In Florida, Bambo et al. (2009) 8 documented 56 percent reduction in nitrate concentr ations under silvopasture compared to 9 conventional open pasture. 10
Blazier et al. (2008) evaluated soil nutrient dynam ics, loblolly pine nutrient composition, and 11 loblolly pine growth of an annually fertilized silv opasture on a well drained soil in Louisiana LA 12 in response to fertilizer type, litter application rate, and subterranean clover. Litter stimulated 13 loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff 14 potential threshold ranges. However, both litter tr eatments led to accumulation of P in upper soil 15 horizons relative to inorganic fertilizer and unfer tilized control treatments. Subterranean clover 16 kept more P sequestered in the upper soil horizon a nd conferred some growth benefits to loblolly 17 pine. The authors concluded that although the these silvopasture systems had a high capacity for 18 nutrient use and retention, litter should be applie d less frequently than in their study to reduce 19 environmental risks. 20
In Florida, Michel et al. (2007) reported that wate r-soluble P concentrations in the upper soil 21 layer ranged from 4 to 11 mg/kg for the silvopastur e sites and 10 to 23 mg/kg in the treeless 22 pasture sites, with higher P concentrations in the treeless pasture at each location. T Total P 23 storage capacity in the upper 1-m depth ranged from 342 to 657 kg/ha in the silvopasture sites 243/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-82 and 60 to 926 kg/ha in the treeless pasture sites ( a negative value indicates that the soil is a P 1

source ) . The results suggest that P buildup within the soi l profile and therefore the chances for 2 loss of P from soil to water water bodies were less from silvopastures than from treel ess pastures. 3
Nair et al. (2007) monitored soil N and P concentra tions under a treeless pasture, a pasture under 4 20-year-old trees, and a pasture of native vegetati on under pine trees in FL.Florida. P 5 concentrations were higher in treeless pasture (mea n: 9.11 mg/kg in the surface) compared to 6 silvopastures (mean: 2.51 mg/kg), and ammonium-N an d nitrate-N concentrations were higher in 7 the surface horizon of treeless pasture. The more e xtensive rooting zones of the combined stand 8 of tree + forage may have caused higher nutrient up take from silvopastures than treeless system. 9 Further, compared to treeless system, soils under s ilvopasture showed higher P storage capacity. 10

Table 2- 22 20 . Summary of reported practice effects resulting fr om silvopasture

. 11

Location Study

type Practice Practice effects Source MO Field Forage planted

in forest stand Cool-season forages benefit from 40% to 60%

shade and grazing trials in such conditions have proven to be successful Garrett et al. 2004

MO Field Forage planted

in forest stand Cumulative forage production in annual

ryegrass/cereal rye planted into a 6-7 year-old forested stand was reduced by ~20% vs. the same forages planted in open pasture. However, beef heifer average daily gain and gain/ha were equal fo r both treatments. Kallenbach et al. 2006

FL Field Silvopasture 56% reduction in nitrate concentrations under silvopasture compared to conventional open pasture Bambo et al. 2009
LA Field Silvopasture

fertilized with poultry litter Litter stimulated tree growth, and did not produce

soil test P concentrations above runoff potential threshold ranges. However, litter treatments led to accumulation of P in upper soil horizons vs. inorganic fertilizer and unfertilized control treatments. Subterranean clover kept more P sequestered in the upper soil horizon and conferred some growth benefits to loblolly pine. Blazier et al. 2008

FL Field Silvopasture Water-soluble P concentrations in the upper soil layer on treeless sites (10 to 23 mg/kg) exceeded those on silvopasture sites (4 to 11 mg/kg) at each location. T Total P storage capacity in the upper 1

- m depth was 342 to 657 kg/ha in the silvopasture site s and -60 to 926 kg/ha in the treeless pasture sites (a negative value indicates that the soil is a P sourc e). Michel et al. ( 2007

FL Field Silvopasture Surface soil P concentrations were higher in treele ss pasture (mean: 9.11 mg/kg) compared to silvopastures (mean: 2.51 mg/kg), and ammonium-N and nitrate-N concentrations were higher in the surface horizon of treeless pasture. The more extensive rooting zones of the combined stand of tree + forage might may have caused higher nutrient uptake from silvopastures than treeless system. Further, compared to treeless system, soils under silvopasture showed higher P storage capacity. Nair et al. 20073/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-83 Practice Costs 1 An analysis of the more than $3.5 billion spent tow ard nutrient controls in the Chesapeake Bay 2 watershed between 1985 and 1996 found that nutrient management (e.g.
, USDA-NRCS 3 Conservation Practice 590) was the least costly pra ctice for nutrient control (Butt and Brown
, 4 2000). 5

Giasson et al. (2003) examined the cost

- effectiveness and the risk of P loss associated wit h 6 various combinations of manure management options f or a typical midsized dairy farm in New 7 York NY using mathematical programming techniques and util ity functions to select optimum 8 management practices. Compared with current practic es, the recommended combination of 9 practices resulted in an approximate 45 percent red uction in the mean area-weighted P Index 10 (64.2 versus vs. 36.1) for a cost (2008 dollars) increase of less t han 2 percent ($171,235 versus vs. 11 $173,860). 12
In an experiment in India, Khose et al. (2003) reported that the cost of broiler pro duction per kg 13 live weight was lowest in the group fed the diet wi th a 50 percent reduction in feed dicalcium 14 phosphate supplemented with phytase. Osei et al. (2008) used an integrated economic and 15 environmental modeling system to evaluate effects impacts of N

- and P

- based manure 16 application rates in Texas. Results of the study in dicate that edge-of-field T total P losses can be 17 reduced by about 0.8 kg/ha/year or 14 percent when manure applications are calibrated to supply 18 all of the recommended crop P requirements from manure T total P sources only versus manure 19 applications at the recommended crop N agronomic ra te. Corresponding economic 20 effects impacts are projected to average a $4,800 annual cost incr ease per farm. 21


### 3.5 Drainage System Design 22 Reduction of nutrient loads from agricultural drain age water has elements of source control (e.g., 23 nutrient management, crop rotations), in-field cont rol (e.g., the drainage system), and edge-of24 field control (e.g., controlled drainage, bioreacto rs). Basic subsurface drainage system design 25 consists of field or lateral drains to collect drai nage from the fields, collectors or mains to collec t 26 the water from the lateral drains, and a ditch or o ther conveyance to convey the collected water 27 away from the field. The size, depth, and spacing o f the drains are key determinants of the 28 drainage rate or drainage intensity (DI). 29

Implementation Measure: Where subsurface drainage is added to an agricultu ral field, design the system to minimize the discharge of N through t ile drains.
Implementation Measure : Where subsurface drainage is added to an agricultur al field, 30 design the system to minimize the discharge of nitr ogen through tile drains

. 31

Practice Effectiveness 32 Subsurface Drainage System Depth and Spacing Effect iveness 33 Several studies performed under different condition s document have documented significant 34 reductions in both discharge volume and nitrate loa ds for shallower and more widely spaced 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-84 drains compared to deeper and more closely spaced d rains (Table 2- 23 21 ). Neither drain spacing 1 nor depth has been shown to have a consistent effec t on nitrate concentration, however. 2

From a

detailed analysis of published field data and simu lation results it was concluded that N 3 losses incre ase with drainage rates or DI because of lowered wa ter tables, increased 4 mineralization of organic matter, reduced denitrifi cation, and increased rates of subsurface water 5 movement to surface waters (Skaggs, Youssef et al. 2005). Factors affecting drainage rates 6 include drain depth, drain spacing, soil properties , hydraulic conductivity, drainable porosity, the 7 depth of the profile through which water moves to t he drains, surface depressional storage, drain 8 diameter, drain envelopes, the size and configurat ion of openings in the drain tube walls, the 9 hydraulic capacity of the drainage network to remov e water from the field, and management 10 (e.g., controlled drainage) of the drainage outlet. Additional factors affecting nitrate losses 11 through drain tiles inclu de climate, fertilization rate, and crop rotations. 12
In a North Carolina study of the effect of subsurfa ce drain depth on nitrate losses from plots 13 receiving swine wastewater applications, the shallo w drainage system (0.75 m deep and 12.5 m 14 apart) had 42 pe rcent less outflow than the deeper drainage system (1.5 m deep and 25 m apart), 15 and nitrate export from the shallow drains (8 kg/ha in 2001 and 27 kg/ha in 2002) was 16 significantly (p=0.10) lower than from the deeper d rains (6 kg/ha in 2001 and 37 kg/ha in 2002) 17 in 2002, but not for the entire 21

- month period (Burchell, Skaggs et al. 2005). Lower nitrate 18 concentrations were observed in the shallow groundw ater beneath the shallow drainage plots 19 because of higher water tables and likely increased denitrificati on, but nitrate concentrations in 20 the drainage water from the shallow drains increase d, possibly due to preferential flow paths to 21 the drains from the surface (hence, shorter retenti on times) and soil pore flushing near the 22 shallow drains. 23

Table 2- 23 21 . Measured effects of changes in drain depth and sp acing 24

Practice Reference practice Reduction vs. reference practice Source

Location Soils and

crops Study

type Depth

(m) Spacing

(m) DI (mm/d) Depth

(m) Spacing

(m) DI (mm/d) Q NO 3 -N

Conc. NO 3 -N

Load NC Swine

wastewater applied Plot 0.75 12.5 1.5 25 42%

- 217% a 1 26% b 2 Burchell
,

Skaggs et al. 2005
0.9 1.2 20% d 4 N/S 18% d 4

13 51 24% d 4 N/S 23% d 4

0.9 13 0.9 51 N/S 19% e 5 48% MN Poorlydrainedsoils; cornsoybean c so ybean 3 Plot

1.2 13 1.2 51 N/S -15% e 5 -1% Sands , Song et al. 2008

0.61 15.24 0.91 30.48 43% g 7 N/ S e S 5 37% h 8

0.61 15.24 1.22 30.48 62% g 7 N/ S e S 5 51% h 8 IL f IL 6 Poorlydrained soils;soybeanscorn Plot

0.91 30.48 1.22 30.48 33% g 7 N/ S e S 5 22% h 8 Cooke, Nehmelman et al. 2002

0.75 20 0.75 5 42% i 9 N/S 44% i 9

0.75 20 0.75 10 19% i 9 N/S 21% i 9 IN Clermont

silt loam, corn for 9 yr, then 6yr cornsoybean Plot

0.75 10 0.75 5 28% i 9 N/S 28% i 9 Kladivko
, Frankenberger et al. 2004

KEY: DI=drainage intensity, Q=drainage water discha rge, N/S=no significant change3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-85 Practice Reference practice Reduction vs. reference practice Source

Location Soils and

crops Study

type Depth

(m) Spacing

(m) DI (mm/d) Depth

(m) Spacing

(m) DI (mm/d) Q NO 3 -N

Conc. NO 3 -N

Load
Notes:

a. FOOTNOTES:
1 Significant increase in 2001 (7.6 mg/L shallow vs. 2.4 mg/L deep), but not significant in 2002 (15.7 m g/L vs. 12.8 mg/L). b. 2 Significant decrease in 2002 (27.3 kg NO 3 -N/ha shallow vs. 36.9 kg NO 3 -N/ha deep) but N/S over a 21-month period.
c. 3 Nitrate concentration (4.4 mg/L greater for corn) a nd load (45% greater for corn) were significantly a ffected by crop type. d. 4 Using adjusted means.
e. 5 Flow-weighted concentrations. f. 6 Findings based on only 1 year of monitoring data. g. 7 Changes in cumulative flow were greater than change s in flow for discrete events. h. 8 Similar load reductions were achieved for discrete events. i. 9 Average of two blocks over 15 years.

From a detailed analysis of published field data an d simulation results it was concluded that N 1 losses increase with drainage rates or DI because o f lowered water tables, increased 2 mineralization of organic matter, reduced denitrifi cation, and increased rates of subsurface water 3 movement to surface waters (Skaggs et al. 2005). Fa ctors affecting drainage rates include drain 4 depth, drain spacing, soil properties, hydraulic co nductivity, drainable porosity, the depth of the 5 profile through which water moves to the drains, su rface depressional storage, drain diameter, 6 drain envelopes, the size and configuration of open ings in the drain tube walls, the hydraulic 7 capacity of the drainage network to remove water fr om the field, and management (e.g., 8 controlled drainage) of the drainage outlet. Additi onal factors affecting nitrate losses through 9 drain tiles include climate, fertilization rate, an d crop rotations. 10
In a North Carolina study of the effect of subsurfa ce drain depth on nitrate losses from plots 11 receiving swine wastewater applications, the shallo w drainage system (0.75 m deep and 12.5 m 12 apart) had 42 percent less outflow than the deeper drainage system (1.5 m deep and 25 m apart), 13 and nitrate export from the shallow drains (8 kg/ha in 2001 and 27 kg/ha in 2002) was 14 significantly (p = 0.10) lower than from the deeper drains (6 kg/ha in 2001 and 37 kg/ha in 2002) 15 in 2002, but not for the entire 21-month period (Bu rchell et al. 2005). Lower nitrate 16 concentrations were observed in the shallow groundw ater beneath the shallow drainage plots 17 because of higher water tables and likely increased denitrification, but nitrate concentrations in 18 the drainage water from the shallow drains increase d, possibly because of preferential flow paths 19 to the drains from the surface (hence, shorter rete ntion times) and soil pore flushing near the 20 shallow drains. 21
Nine subsurface drainage plots in Minnesota were mo nitored for 5 years to investigate the role of 22 subsurface drainage depth and DI drainage intensity on nitrate loads to subsurface drains (Sands
, 23 Song et al. 2008). Three plots had a depth of 120 cm (c onventional depth) and a spacing of 24 m, 24 resulting in a calculated DI of 13 mm/d (convention al rate), while two plots had a depth of 90 cm 25 and a spacing of 18 m that was calculated to also achieve the conventio nal DI of 13 mm/d. Two 26 plots each had depth/spacing combinations of 120 cm /12 m and 90 cm/9 m, designed to simulate 27 the intensification of drainage systems experienced in the area. Analysis of aggregated data 28 showed that both shallower and less intense drain s ystems reduced both discharge (20 percent 29 and 24 percent, respectively) and nitrate loading ( 18 percent and 23 percent, respectively), but 303/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-86 not flow-weighted nitrate N nitrogen concentration. Interaction effects, however, indic ated that 1 intense drainage increased nitrate concentration fo r shallow drainage
, but diluted nitrate 2 concentrations for drains at conventional depth. Be cause of that this , nitrate loads increased 3 significantly for shallow drainage when combined wi th increased DI drainage intensi ty , while 4 nitrate loads for conventional drainage depth remai ned at a similar level despite increased 5 DI drainage intensity

. 6
In a 1-year study of tile effluent from drainage ti les installed at different depths in a 16-ha field 7 in Illinois, Cooke et al. (2002) it was found that tile discharge decreased with decreasing tile 8 depth for tiles at 0.61m, 0.91m, and 1.22m depth (Cooke, Nehmelman et al. 2002) . Cumulative 9 discharge from the monitored tile lines at 0.61m an d 0.91m depth were 43 percent and 33 percent 10 less, respectively, than discharge from the tile li ne at 1.22m, and average nitrate load reductions 11 for the 0.61m and 0.91m tile lines, when compared t o the tile line at 1.22m, were 51 percent and 12 22 percent, respectively. There was no relationship between flow-weighted nitrate concentration 13 and tile depth, and the authors recommend that more data are required to validate the findings. 14

A 15- year yr

drainage study in Indiana to evaluate three drain spacings (5, 10, and 20 m) installed 15 at a depth of 0.75 m showed that both discharge and nitrate load were reduced significantly as 16 drain spacing was increased
, but that flow-weighted nitrate concentration did n ot vary with drain 17 spacing (Kladivko , Frankenberger et al. 2004). Differences in nitrate loads with sp acing occurred 18 primarily during the years with continuous corn, hi gh fertilizer N rates, and no cover crop. 193/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-87 

## 4

. Implementation Measures and Practices for Edge

- of

1 

## Field Trapping and Treatment 2 Edge

- of

- field practices remediate or intercept the pollutan t before or after it is delivered to the 3 water resource , if the pollutants have not been effectively contro lled at the source or in the field. 4 Wetlands, drainage water management, and buffers an d setbacks are examples of be important 5 edge

- of

- field or end

- of

- pipe measures to prevent nutrient loads to the Chesapeake Bay. 6



### 4.1 Buffers and Minimum Setbacks 7 Buffers are described in Chapter 5 of this document

. 8

Implementation Measure: Integrate into farm plans fertilizer application b uffers or minimum setbacks from in-field ditches, intermittent stream s, tributaries, and surface waters.

Buffers are described in Chapter 5 of this guidance. 9
Implementation Measure : Integrate buffers or minimum setbacks from in

- field ditches, 10 intermittent streams, tributaries and surface waters from fertili zer application into farm 11 plan

. 12

Practice Effectiveness 13 Merriman et al. (2009) developed a compilation of B MP effectiveness results. Table 2- 24 22 14 presents a listing of individual results for conser vation buffer practices along with percent 15 reductions for TP, TN
, and sediment. Additional data on reductions for pa rticulate P, dissolved 16 P, NO 3 -N, and ammonium are also available. 17

Table 2- 24 22 . TP, TN, and sediment Sediment reductions for various conservation buffer practic es 18 as compiled by Merr iman et al. (2009). 19 Reference (as cited by Merriman et al. 2009) State BMP name Study scale Slopes HSG T Total P % T Total

N % Total sediment % Bingham et al. 1980 North

Carolina Contour Buffer Strip

(3 m) Field plot 3-8 B 52.77 % 18.6 %

Bingham et al. 1980 North

Carolina Contour Buffer Strip

(3 m) Field plot 3-8 B 7.91 % 14.53 %

Udawatta et al. 2002 Missouri Contour Buffer Strip (4.5 m) Small

watershed 0-3 D 26 % 20 % 19 %

Udawatta et al. 2002 Missouri Contour Buffer Strip (4.5 m) Small

watershed 3-8 D 26 % 20 % 19 %

McGregor et al. 1999 Mississippi Hedgerow Planting Field plot 3-8 C 76 %

Meyer et al. 1995 Mississippi Hedgerow Planting Lab plot 3-8 B 80 %

Sheridan et al. 1999 Georgia Riparian Forest Buffer Field 0-3 < N/A > 95 %3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-88 Reference (as cited by Merriman et al. 2009) State BMP name Study scale Slopes HSG T Total P % T Total

N % Total sediment % Sheridan et al. 1999 Georgia Riparian Forest Buffer Field 0-3 < N/A > 74 %

Sheridan et al. 1999 Georgia Riparian Forest Buffer Field 0-3 < N/A > 68 %

Lowrance and Sheridan

, 2005 Georgia Riparian Forest Buffer Farm 0-3 B/D 56 % 37 %

Blanco-Canqui et al. 2004 Missouri Vegetated Filter Strip (VFS) Field plot 3-8 D 95 %

Dillaha et al. 1988 Virginia VFS Vegetated Filter Strip Field plot 3-8 C 2 % 1 % 31 %

Srivastava et al. 1996 Arkansas VFS Vegetated Filter Strip Field plot 3-8 C 65.5 % 67.2 %

Srivastava et al. 1996 Arkansas VFS Vegetated Filt er Strip Field plot 3-8 C 36 % 43.9 %

Dillaha et al. 1988 Virginia VFS Vegetated Filter Strip Field plot 8-15 C 63 % 64 % 87 %

Feagley et al. 1992 Louisiana VFS Vegetated Filter Strip Field plot < N/A > D 78.49 %

Chaubey et al. 1995 Arkansas VFS Vegetative Filt er Strip (15.2 m) Field plot 3-8 C 86.8 % 75.7 %

Sanderson et al. 2001 Texas VFS Vegetative Filter Strip (16.4 m) Field plot < N/A > C 47 %

Sanderson et al. 2001 Texas VFS Vegetative Filter Strip (16.4 m) Field plot < N/A > C 76 %

Chaubey et al. 1995 Arkansas VFS Vegetative Filter Strip (21.4 m) Field plot 3-8 C 91.2 % 80.5 %

Daniels and Gilliam

. ., 1996 North

Carolina VFS Vegetative Filter

Strip (3 m) Field 3-8 B 55 % 40 % 53 %

Blanco-Canqui et al. 2004 Missouri VFS Vegetative Filter Strip (4 m) Field plot 3-8 D 77 % 91 %

Chaubey et al. 1995 Arkansas VFS Vegetative Filter Strip (4 m) Field plot 3-8 C 39.6 % 39.2 %

Parsons et al. 2001 North

Carolina VFS Vegetative Filter

Strip (4 m) Field plot < N/A > < N/A > 50 % 50 %

Mendez et al. 1999 Virginia VFS Vegetative Filter Stri p (4.3 m) Field plot 15-25 C 55.6 % 81.9 %

Dillaha et al. 1989 Virginia VFS Vegetative Filter Strip (4.6 m) Field plot 3-8 C 85 % 84 % 83 %

Dillaha et al. 1989 Virginia VFS Vegetative Filter Strip (4.6 m) Field plot 8-15 C 73 % 73 % 86 %

Dillaha et al. 1988 Virginia VFS Vegetative Filter Strip (4.6 m) Field plot 15-25 C 52 % 69 % 76 %

Dillaha et al. 1989 Virginia VFS Vegetative Filter Strip (4.6 m) Field plot 15-25 C 49 % 47 % 53 %

Daniels and Gilliam

. ., 1996 North

Carolina VFS Vegetative Filter

Strip (6 m) Field 3-8 B 65 % 48 % 68 %

Chaubey et al. 1995 Arkansas VFS Vegetative Filter Strip (6.1 m) Field plot 3-8 C 58.4 % 53.5 %3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-89 Reference (as cited by Merriman et al. 2009) State BMP name Study scale Slopes HSG T Total P % T Total

N % Total sediment % Srivastava et al. 1996 Arkansas VFS Vegetative Filter Strip (6.1 m) Field plot 3-8 C 25.5 % 21.4 %

Mendez et al. 1999 Virginia VFS Vegetative Filter
s trip (8.5 m) Field plot 15-25 C 81.5 % 90.2 %

Coyne et al. 1995 Kentucky VFS Vegetative Filter Strip (9 m) Field plot 8-15 B 99 %

Dillaha et al. 1988 Virginia VFS Vegetative Filter Strip (9.1m) Field plot 3-8 C 19 % 9 % 58 %

Dillaha et al. 1989 Virginia VFS V egetative Filter Strip (9.1m) Field plot 3-8 C 87 81 % 93 %

Dillaha et al. 1988 Virginia VFS Vegetative Filter Strip (9.1m) Field plot 8-15 C 80 % 80 % 95 %

Dillaha et al. 1989 Virginia VFS Vegetative Filter Strip (9.1m) Field plot 8-15 C 93 % 93 % 98 %

Dillaha et al. 1988 Virginia VFS Vegetative Filter Strip (9.1m) Field plot 15-25 C 57 % 72 % 88 %

Dillaha et al. 1989 Virginia VFS Vegetative Filter Strip (9.1m) Field plot 15-25 C 65 % 59 % 70 %

Chaubey et al. 1995 Arkansas VFS Vegetative Filter Strip (9.2 m) Field plot 3-8 C 74 % 66.6 %

Source: Merriman et al. 2009

1
Liu et al. (2008) performed an extensive review of sediment trapping efficiencies from more than 2 80 representative BMP experiments. A summary of the ir data is presented in Table 2- 25 23 . Their 3 analysis of the t hese data indicate indicated that regardless of the area ratio of buffer to 4 agricultural field, a 10-m buffer and a 9 percent s lope optimize optimized the sediment

- trapping 5 capability of vegetated buffers. 6

Table 2- 25 23 . Summary of VFS characteristics and corresponding sediment

- trapping efficiencies 7 (source: Liu et al. 2008). 8

BMP Location Buffer width Area ratio Slope Sediment

trapping efficacy Inflow Outflow Mass sediment reduction Paper source m buffer/plot ------------%----------- --------------------------kg-----------------------

-- Young et al. (1980) VFS† 4.06 0.028 4 79 35.37 6.4 28.97 Hall et al. (1983) VFS Pennsylvania 6 0.27 14 76 0.000008 0.000002 0.000006 Hayes and Hairston (1983) VFS Mississippi 2.6 2.35 60 Dillaha et al. (1989) VFS Virginia 9.1 0.5 11 97.5 VFS Virginia 4.6 0.25 11 86 VFS Virginia 9.1 0.5 16 70.5 VFS Virginia 4.6 0.25 16 53.5 VFS Virginia 9.1 0.5 5 93 VFS Virginia 4.6 0.25 5 83.5 Magette et al. (1989) VFS Maryland 9.2 0.42 2.7 92.4 70.8 5.4 65.4 VFS Maryland 4.6 0.21 2.7 82.8 70.8 12.2 58.6 VFS Maryland 9.2 0.42 2.7 88.3 16.2 1.9 14.33/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-90 BMP Location Buffer width Area ratio Slope Sediment

trapping efficacy Inflow Outflow Mass sediment reduction Paper source m buffer/plot ------------%----------- --------------------------kg-----------------------

-- VFS Maryland 4.6 0.21 2.7 64.3 13.6 4.97 11.23 VFS Maryland 9.2 0.42 4.1 80.3 13.6 2.68 10.92 VFS Maryland 4.6 0.21 4.1 65.8 4.65 8.95 Partons et al. (1990) VFS North Carolina 4.3 0.12 3.25 75 VFS North Carolina 8.5 0.23 3.25 85 Parsons et al. (1994) VFS North Carolina 4.3 0.12 1.9 78 VFS North Carolina 8.5 0.23 1.9 81 Coyne et al. (1995) VFS Kentucky 4.6 0.4 9 99 0.014 0.002 0.012 Arora et al. (1996) VFS Iowa 20.12 0.033 3 83.6 VFS Iowa 20.12 0.067 3 87.6 Daniels and Gilliam (1996) VFS North Carolina 3 0.034 4.9 59 VFS North Carolina 6 0.071 4.9 61 VFS North Carolina 3 0.034 2.1 45 VFS North Carolina 6 0.071 2.1 57 Robinson et al. (1996) VFS Iowa 3 0.05 7 70 VFS Iowa 3 0.05 12 80 VFS Iowa 9.1 0.15 12 85 VFS Iowa 9.1 0.15 7 85 Van Dijk et al. (1996) VFS Netherlands 1 5.2 49.5 VFS Netherlands 4 5.2 78.5 VFS Netherlands 5 2.3 73 VFS Netherlands 10 2.3 94 VFS Netherlands 5 2.5 64.5 VFS Netherlands 10 2.5 99 VFS Netherlands 5 8.5 92 VFS Netherlands 10 8.5 97.5 Patty et al. (1997) VFS Brittan, France 6 0.12 7 98.9 493.2 5.44 487.76 VFS Brittan, France 12 0.24 7 99 493.2 3.7 489.5 VFS Brittan, France 18 0.36 7 99.9 493.2 0.37 492.83 VFS Brittan, France 6 0.12 10 87 20.4 2.53 17.87 VFS Brittan, France 12 0.24 10 100 20.4 0 20.4 VFS Brittan, France 18 0.36 10 100 20.4 0 20.4 VFS Brittan, France 6 0.12 15 91 309.16 28.71 280.45 VFS Brittan, France 12 0.24 15 97 309.16 8.21 300.95 VFS Brittan, France 18 0.36 10 98 309.16 4.8 304.36 Barfield et al. (1998) VFS Kentucky 4.57 0.21 9 97 258 8.44 249.56 VFS Kentucky 9.14 0.41 9 99.9 212 1.1 210.9 VFS Kentucky 13.72 0.62 9 99.7 361 2.06 358.94 Coyne et al. (1998) VFS Kentucky 9 0.41 9 99 VFS Kentucky 4.5 0.24 9 95 VFS Kentucky 9 0.67 9 98 Tingle et al. 1998) VFS Mississippi 0.5 0.018 3 88 0.018 0.0022 0.0158 VFS Mississippi 1 0.045 3 93 0.036 0.0024 0.0336 VFS Mississippi 2 0.09 3 94 0.072 0.004 0.068 VFS Mississippi 3 0.14 3 96 0.108 0.0048 0.1032 VFS Mississippi 4 0.18 3 98 0.144 0.0032 0.1408 Munoz-Carpena et al. (1999) VFS North Carolina 4.3 0.11 6 86 64.76 1.74 63.02

VFS North Carolina 8.5 0.22 6 93 54.88 3.99 50.893/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-91 BMP Location Buffer width Area ratio Slope Sediment

trapping efficacy Inflow Outflow Mass sediment reduction Paper source m buffer/plot ------------%----------- --------------------------kg-----------------------

-- Schmitt et al. (1999) VFS Nebraska 7.5 0.093 6.5 85 3.99 1.3 2.69 VFS Nebraska 15 0.19 6.5 96 3.01 0.84 2.17 Sheridan et al. (1999) VFS Georgia 8 0.03 2.5 81 Lee et al. (2000) VFS Iowa 7.1 0.32 5 70 2.82 0.85 1.97 Abu-Zreig et al. (2004) VFS Canada 2 0.2 2.3 68 5887 1876 4011 VFS Canada 15 0.025 2.3 98 9324 219 9105 Blanco-Canqui et al. (2004) VFS Columbia, MO 8 0.09 5 90 1.6*10 -8 1.3*10 -10 1.58*10 -8 Borin et al. (2005) VFS Northeast Italy 6 1.8 94 3450 200 3250 Helmers et al. (2005) VFS Nebraska 13 0.06 1 80 147 29 118 Gharabaghi et al. (2006) VFS Ontario, Canada 2.5 50

VFS Ontario,

Canada 20 98

Young et al. (1980) Riparian buffer 21.3 4 78

Riparian buffer 27.4 4 79

Peterjohn and Correll (1984) Riparian buffer Maryland 19 5 90

Riparian buffer Maryland 60 5 94 3.99 1.3 2.69

Dillaha et al. (1988) Riparian buffer 4.6 11 87

Riparian buffer 4.6 16 76

Riparian buffer 9.1 11 95

Riparian buffer 9.1 16 88

Dillha et al. (1989) Riparian buffer 4.6 11 86 0.1*10 -6 0.2*10 -7 0.8*10 -7

Riparian buffer 4.6 16 53 2.3*10 -7 1.1*10 -7 1.2*10 -7

Riparian buffer 9.1 11 98 2*10 -7 0.1*10 -7 1.9*10 -7

Riparian buffer 9.1 16 70 4.5*10 -7 1.4*10 -7 3.1*10 -7

Fiener and Auerswald (2003) Grassed waterways Munich 35 0.16 9.3 97 330.72 7.42 323.3

Grassed waterways Munich 17.5 0.12 9 77 175.74 40.02 135.72

Fiener and Auerswald (2005) Grassed waterways Central Europe 18.5 0.076 3.6 93

† VFS represents vegetated filter strips.

Source: Liu et al. 20083/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-92 1

23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-93 13/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-94 1

23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-95 1
2 Ghadiri et al. (2001) developed a set of laboratory experiments with a tilting flume to investigate 3 the effects of buffer strips on flow hydrology and sediment transport/deposition in and around 4 the strips. The investigators found that flow retar dation initiates above the strip and can begin to 5 remove sediment. The results summarized in Table 2-26 Exhibit 5 show sediment deposition 6 ranging from 18 to 77 percent, but caution is advis ed when applying those these laboratory results 7 to field conditions. In a study of simulated filter strips, Jin et al. (2002) found that adding 8 addition of a mulch barrier increased the sediment trapping eff iciency of filter strips by 10

– - 60 9 percent compared with the same flow, slope, and fil ter strip conditions without mulch. The 10 observed interactions of crop residue mulches and f ilter strips suggest that combining residue 11 management systems with vegetative buffer strips co ntaining an upslope edge of strong 12 vegetation offer potential synergies for increased conservation effectiveness. Jin and Romkens 13 (2001) found that over 80 percent of the sediment t rapped by a vegetative or vegetated filter strip 14 (VFS) was deposited in the approach channel to the VFS and in the upper half of the VFS, with 15 most of the deposited sediment particles larger tha n 150 μm um in diameter. As the slope 16 increased, deposition moved downstream and deposite d sediment became larger. 17

Table 2- 26 24 . Effect of high-density grass strip 18 Table 1. The effect of high-density grass strip on sediment concentration on different slopes Sediment concentration

(g/L) Sediment deposited (%) Slope (%) Unaffected

flow In the

backwater After grass

strip In the

backwater Inside grass

strip
1.5 1.25 1.02 1.06 18 -4
2.0 4.30 3.11 3.20 28 +3
3.4 17.44 10.76 11.01 38 -2
5.2 78.63 18.15 16.81 77 +7

Source (source : Ghadiri et al. 2001 )3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-96 1

2 In a field experiment in Ontario, Gharabaghi et al. (2001) compared sediment removal efficiency 3 using a variety of filter widths (2.44, 4.88, 9.67 and 19.52 m), flow rates, and slopes. They The 4 investigators found that sediment removal ranged from 50 to 98 p ercent , and generally found 5 little improvement for widths greater than 10 m. Se diment removals are depicted in Figure 2-3. 6

7 Source: Gharabaghi et al. 20013/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-97 Figure 2-3. Average sediment-removal efficiency Sediment Removal Efficiency of VFS. Vegetative 1 Filter Strips 2 (source: Gharabaghi et al. (2001) ) 3

4

5

6 With the Raritan Basin in New Jersey serving as a c ase study, Qiu et al. (2009) compared the 7 placement of fixed-width buffers using based on regulatory rules, variable-width buffers 8 according to based on watershed initiatives, and variable source area-ba sed conservation buffer 9 placement strategy derived from an alternative conc ept of watershed hydrology. The authors 10 show that there is little difference in cost

- effectiveness between fixed- and variable-width 11 buffers
, but that the variable source area-based buffer pla cement strategy (which targets the most 12 hydrologically critical source areas in a watershed tier buffer placement) is more cost

- effective. 13
In a riparian buffer in Connecticut, one-half of a 35 m x 250 m riparian buffer cropped in corn 14 was seeded with fine

- leaf fescue and allowed to remain idle (Clausen et al. 2000). TKN and TP 153/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-98 concentrations significantly ( p P < 0.05) increased as ground ground water flowed through the 1 restored buffer, while nitrate concentrations decli ned significantly with most (52 percent) of the 2 decrease occurring within a 2.5-m wetland adjacent to the stream. An N mass balance for the 3 2.5-m strip indicated that denitrification only accounted for only 1 percent of the N losses and 4 plant uptake accounted for 7

– to 13 percent of the N losses annually. Ground Ground water was 5 the dominant source of N to the buffer and also the dominant loss pathway. Restoration of the 6 riparian buffer decreased (p < 0.05) overland flow concentrations of TKN by 70 percent, NO 3 -N 7 by 83 percent, TP by 73 percent, and TSS by 92 perc ent as compared with the control. 8 Restoration reduced (p < 0.05) NO 3 -N concentrations in ground ground water by 35 percent as 9 compared with the control. Underestimated denitrifi cation and dilution by upwelling ground 10 water in the wetland area adjacent to the stream we re believed to be primarily responsible for the 11 decreasing NO 3 -N concentrations observed. 12
In a plot stuidy, Dosskey et al. (2007) examined wh ether filter strip effectiveness changes over 13 years since establishment and if temporal change de pends on vegetation type. Plots containing 14 all-grass (New Grass) and grass with trees and shru bs (New Forest) were established in 1995 15 among plots that contained either grass since 1970 (Old Grass) or were re

- cultivated and re

16 planted annually with grain sorghum (Crop). Once ea ch summer, in 1995, 1996, 1997, 2003, and 17 2004, identically prepared solutions containing sed iment, N and P fertilizer, and bromide tracer 18 were applied to the upper end of each plot during a simulated rainfall event. The authors 19 concluded that filter strip performance improves ov er a period of years since establishment, with 20 most of the change occurring within three growing s easons after establishment. Infiltration 21 characteristics account for most of that change, an d grass and forest vegetation are equally 22 effective as filter strips for at least 10 growing seasons after establishment. 23
Lee et al. (2003) used a field plot study to determ ine the effectiveness of an established multi24 species buffer in trapping sediment, N nitrogen , and P phosphorus from cropland runoff during 25 natural rainfall events. A switchgrass buffer remov ed 95 percent of the sediment, 80 percent of 26 the N, 62 percent of the nitrate-nitrogen (NO 3 -N), 78 percent of the P, and 58 percent of the 27 phosphate-phosphorus (PO 4 -P), while a switch switch grass/woody buffer removed 97 percent of 28 the sediment, 94 percent of the TN total

- N , 85 percent of the NO 3 -N, 91 percent of the TP total

- P
, 29 and 80 percent of the PO 4 -P in the runoff. In an earlier study using the sam e plots, Lee et al. 30 (2000) found generally similar results; during a 2- hour hr rainfall simulation at 25 mm/h, the 31 switchgrass buffer removed 64, 61, 72, and 44 perce nt of the incoming T total N, NO 3 -N, T total 32 P, and PO 4 -P, respectively. The switch switch grass-woody buffer removed 80, 92, 93, and 85 33 percent of the incoming T total N, NO 3 -N, T total P, and PO 4 -P, respectively. During a 1-hour 34 rainfall simulation at 69 mm/h, the switchgrass buf fer removed 50, 41, 46, and 28 percent of the 35 incoming T tot al N, NO 3 -N, T total P, and PO 4 -P, respectively, The switchgrass-woody plant 36 buffer removed 73, 68, 81, and 35 percent of the in coming T total N, NO 3 -N, T total P, and PO 4 -P, 37 respectively. In both studies, the switchgrass buff er was effective in trapping coarse sediment 38 and sediment-bound nutrients, but the additional bu ffer width with high infiltration capacity 39 provided by the deep-rooted woody plant zone was ef fective in trapping the clay and soluble 40 nutrients. 41
Using a set of 36 field lysimeters with six differe nt ground covers (bare ground, orchardgrass, 42 tall fescue, smooth bromegrass, timothy, and switch grass), Lin et al. (2007) evaluated the ability 43 of grasses to reduce nutrient levels in soils and s hallow groundwater. The leachate from each 443/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-99 lysimeter was collected after major rainfall events during a 25-day period, and soil was collected 1 from each lysimeter at the end of the 25-day period . Grass treatments reduced NO 3 -N levels in 2 leachate by 74.5 to 99.7 percent compared to the ba re ground control, but timothy was 3 significantly less effective at reducing NO 3 -N leaching than the other grasses. Switchgrass 4 decreased PO 4 -P leaching to the greatest extent, reducing it by 60.0 to 74.2 percent compared to 5 the control. In a separate study, Bedard-Haughn et al. (2005) found that cutting vegetative 6 buffers increased the uptake of NO 3 -N 2.3 times that of uncut buffers. 7 The influence of vegetation characteristics, buffer width, slope, and stubble height on sediment 8 retention was evaluated in a Montana study using th ree vegetation types (sedge wetland, rush 9 transition, bunchgrass upland) on plots spanning 2 to 20 percent slopes (Hook
, 2003). Sediment 10 retention was affected strongly by buffer width and moderately by vegetation type and slope, but 11 it was not affected by stubble height. Mean sediment r etention ranged from 63 to > 99 percent 12 for different combinations of buffer width and vege tation type, with 94 to 99 percent retention in 13 6-m-wide buffers regardless of vegetation type or s lope. Results suggest that rangeland riparian 14 buffers should be at least 6 m wide, with dense veg etation, to be effective and reliable. 15
Mankin et al. (2007) studied the effectiveness of e stablished grass-shrub riparian buffer systems 16 in reducing TSS, P, and N using simulated runoff on nine plots with widths ranging from 8.3 to 17 16.1 m. Vegetation types were all natural selection grasses (control), a 2-segment buffer with 18 native grasses and plum shrub, and a 2-segment buff er with natural selection grasses and plum 19 shrub. Removal efficiencies were strongly linked to infiltration, with TSS mass and 20 concentration reductions averaging 99.7 percent and 97.9 percent, TP reductions of 91.8 percent 21 and 42.9 percent, and TN reductions at 92.1 percent and 44.4 percent. Mankin et al. (2007) 22 concluded that adequately designed and implemented grass-shrub buffers with widths of 8 m 23 provide for water quality improvement, particularly if adequate infiltration is achieved. 24
Hoffman et al. (2009) examined the main hydrologica l pathways for P losses from and P 25 retention in riparian buffers. They determined that P retention rates of up to 128 kg P/ha-yr 26

can may be accounted for by sedimentation, while plant upt ake can may temporarily immobilize 27 up to 15 kg P/ha-yr. Dissolved P retention is often below 0.5 kg P/ha-yr
, and the authors note 28 that several studies have shown significant release of dissolved P up to 8 kg P/ha-yr. 29
In Finland, the effects of 10

- m

– wide
, annually cut grass buffer zones (GBZ) and vegetated 30 buffer zones under natural vegetation (VBZ) were compared on 70

- m

- long x 18

- m

- wide plots 31 with no buffer zone (Uusi-Kamppa 2006). Retention o f TS, TP and PP was > 50, 40, and > 45 32 percent, respectively, for both treatments. 33
In northeast Italy, a 5

- m

- wide grass strip and a 1

- m wide row of trees were evaluated with corn 34 and wheat from 1997 to

- 1999 (Borin and Bigon 2002). Under a variety of fe rtilization levels and 35 tree sizes, water discharged from the strip was alw ays below 2 ppm. Tree size showed no evident 36 effect on the reduction of the concentration. In a companion study from 1998 to

- 2001, Borin et 37 al. (2005) evaluated 6

- m buffer strips with adjoining fields of corn-wheat -soybeans. The buffer 38 strip was composed of two rows of regularly alterna ting trees and shrubs, with grass in the inter39 rows. Total runoff was reduced by 78 percent. TSS c oncentrations at the control was 2

– - 7 times 40 greater than the TSS of 0.14 mg/L from the buffer s trip. N concentrations through the buffer strip 41 were higher than control, but mass loadings were re duced from 17.3 to 4.5 kg/ha. 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-100 

### 4.2 Wetlands 1
Implementation Measure: Protect and restore wetlands and riparian areas fr om adverse effects and maintain such nonpoint source abatement functio n while protecting other existing functions of the wetlands and riparian areas as measured by c haracteristics such as vegetative composition and cover, hydrology of surface water and groundwat er, geochemistry of the substrate, and species composition.
Implementation measure : Protect and restore wetlands and riparian areas from adverse 2 effects and maintain this nonpoint source abatement function while protecting other 3 existing functions of these wetla nds and riparian areas as measured by characteristics such 4 as vegetative composition and cover, hydrology of s urface water and ground water, 5 geochemistry of the substrate, and species composit ion. 6
Properly functioning natural wetlands and riparian areas (Chapter 5) can significantly reduce 7 nonpoint source pollution by intercepting surface r unoff and subsurface flow and by settling, 8 filtering, or storing sediment and associated pollu tants. Wetlands and riparian areas typically 9 occur as natural buffers between uplands and adjace nt water water bodies. Loss of such these 10 systems allows a more direct contribution of nonpoi nt source pollutants to receiving waters. 11 Degraded wetlands and riparian areas can may even become pollutant sources. Thus, natural 12 wetlands and riparian areas should be protected and should not be used as designated erosion 13 control practices. Their nonpoint source control fu nctions are most effective as part of an 14 integrated land management system focusing on nutri ent, sediment, and erosion control practices 15 applied to upland areas. 16
Protection of the full range of functions for wetla nds and riparian areas are discussed in National 17 management measures to protect and restore wetlands and riparian areas for the abatement of 18 nonpoint source pollution (USEPA
, 2005). Protection of wetlands and riparian areas s hould 19 allow for both nonpoint source pollution control an d maintenance of other benefits of these 20 natural aquatic systems, e.g.
, wildlife habitat. 21
Examples of implementation practices for protecting wetlands and riparian areas include the 22 following : 23

• Identify existing functions of those wetlands and r iparian areas with significant nonpoint 24

source NPS control potential when implementing NPS management practices. 25

• Do not alter wetlands or riparian areas to improve their water quality functions at the 26 expense of their other functions. 27

• Use appropriate preliminary treatment practices suc h as vegetated treatment systems or 28 detention or retention basins to prevent adverse effects on impacts to wetland functions 29 that affect nonpoint source NPS pollutant abatement from hydrologic changes, 30 sedimentation, or contaminants. 31
Wetlands and their functions related to reducing tr ansport of agricultural pollutants are described 32 in existing guidance (USEPA
, 2003). 333/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-101 Practice Effectiveness 1 Fisher and Acreman (2004) gathered data from 57 wet lands from around the world to evaluate 2 nutrient removal efficacy. Table 2- 27 25 displays a list of those wetlands, and Figure Table 2- 4 8 3 displays the removal efficiencies for N nitrogen and phosphorous as a function of loading—note 4 that the trend for N nitrogen is statistically significant while the regression line for P phosphorus is 5 not. 6

Table 2- 27 25 . Summary of wetlands wetland evaluated 7 Summary of references studied showing wetland name, wetland type . (Fisher and country of location. References are split into those showing an increase in nutrient lo ading, decrease in nutrient loading and those showi ng no change. Acreman, 2004) Author(s) Date N or P Wetland name Wetland type Country Nutrient Retention
Raisin and Mitchell 1995 TPN Humphrey’s wetland Mash/swamp Australia
Raisin and Mitchell 1995 TP Reid’s wetland Mash/swamp Australia Jacobs and Gilliam 1985 NO 3 Unknown Riparian USA Cooper and Gilliam 1987 P Unknown Riparian USA
Lowrance et al. 1984 NO 3 Unknown Riparian USA Cooke 1994 P, NO 3 Unknown Mash/swamp NZ Bugenyi 1993 N, P Unknown Riparian Uganda
Patruno and Russell 1994 N, P Yamba wetland Marsh/swamp Australia Baker and Maltby 1995 NO 3 , NO 4 Kismeldon Meadows and Bradford Mill Riparian UK

Peterjohn and Correll 1984 sol P Rhode River drainage basin Riparian USA
Jordan et al. 1993 NO 3 , TP Chester River catchment Floodplain USA Gehrels and Mulamootth 1989 TP Unknown Marsh/swamp USA
Burt el al. 1998 NO 3 R. Leach floodplain Floodplain UK Haycock and Burt 1993 NO 3 R. Leach floodplain Floodplain UK Cooper 1994 NO 3 Unknown Swamp NZ
Prior 1998 N, P R. Lambourn floodplain Floodplain UK Haycock and Pinay 1993 NO 3 R. Leach floodplain Riparian UK Chauvelon 1998 N, P Rhone river delta Riverine delta France Maltby et al. 1995 N Floodplains in Devon Floodplain UK Osborne and Totome 1994 TP, SRP, NH 4 Waigani Marsh/swamp Papua N. Guinea Cooper 1990 NO 3 Scotsman Valley, NZ Riparian NZ
Lindkvist and Hakansson 1993 TP Unknown Unknown Sweden
Lindkvist 1992 TP Unknown Unknown Sweden
Mander et al. 1991 TP Unknown Various Estonia Nunez Delgado et al. 1997 NO 3 Unknown Riparian Spain
Mander et al. 1997 N, P Porijogi River catchment Riparian Estonia
Downes et al. 1997 NO 3 Whangamata Stream Riparian NZ
Brinson et al. 1984 N, P Tar River floodplain Riparian USA
Brunet 1994 PN Adour River floodplain Floodplain France
Tilton and Kadlec 1979 N, P Unknown Fen USA
Burke 1975 N, P Unknown Peatland Ireland Boyt et al. 1977 P Unknown Marsh/swamp USA3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-102 Author(s) Date N or P Wetland name Wetland type Country Spangler 1977 P Unknown Marsh/swamp USA Yonika and Lowry 1979 N Unknown Marsh/swamp USA Semkin et al. 1976 N, P Unknown Marsh/swamp USA Semkin et al. 1976 N, P Unknown Marsh/swamp USA
Johnston et al. 1984 N, P nr White Clay Lake Marsh/swamp USA
Johnston et al. 1984 N, P nr White Clay Lake Riparian USA Pinay and Decamps 1988 N Garonne Valley Riparian France
Jordon et al. 2003 TN, TP Kent Island Marsh/swamp USA
Mwanuzi et al. 2003 P0 4 Unknown Riparian Tanzania Rzepecki 2002 sol P Unknown Riparian Poland Zhang et al. 2000 TN, TP Unknown Marsh/swamp USA
Bratli et al. 1999 N, P Unknown Marsh/swamp Norway Kellog and Bridgeham 2003 P0 4 Unknown Peatland USA Kansiime and Nalubega 1999 N Unknown Marsh/swamp Uganda Kansiime and Nalubega 1999 N Unknown Marsh/swamp Uganda Chescheir et al. 1991 TP, NO 3 Unknown Riparian USA Dorge 1994 NO 3 Rabis Baek Peatland Denmark Dorge 1994 NO 3 Syvbaek Riparian Denmark Dorge 1994 NO 3 Glumso Marsh/swamp Denmark Schlosser and Karr 1981 TP Champaign-Urbana Riparian USA
Hanson et al. 1994 NO 3 nr Kingston Riparian USA Schwer and Clausen 1989 TP, TN nr Charlotte Riparian USA Daniels and Gilliam 1996 N, P Cecil soil area Riparian USA

Nutrient Addition Cook 1994 NO 3 Unknown NZ Peterjohn and Correll 1984 sol P Unknown Riparian USA
Jordan et al. 1993 N, P Chester River catchment Floodplain USA Gehrels and Mulamootth 1989 sol P Unknown Marsh/swamp USA
Prior 1998 TDN, TDP R. Lambourne floodplain Floodplain UK Osborne and Totome 1994 NO 2, NO 3 Waigani Marsh/swamp Papua N. Guinea
Downes et al. 1997 NO 3 , SRP Whangamata Stream Riparian NZ Clausen et al. 1993 TN Unknown Riparian USA Daniels and Gilliam 1996 N, P Georgeville soil area Riparian USA

No Nutrient Retention/Addition
Raisin and Mitchell 1995 TPN Reid’s wetland Marsh/swamp Australia
Kadlec 1985 P Unknown Marsh/swamp USA
Elder 1985 N Apalachicola River floodplain Floodplain USA Ontkean et al. 2003 N, P Hilton Wetland Pond Canada Daniels and Gilliam 1996 TP, PO 4 Georgeville soil area Riparian USA Source: Adapted from Fisher and Acreman 2004
Notes: N = several N species, P = several P species , TP = total phosphorus, TN = total or Kjeldahl N, sol = soluble N or P, SRP = soluble reactive P, TPN = total particula te N, PN = particulate N, PO4 = orthophosphate, NO3 = nitrate, NO23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-103 Author(s) Date N or P Wetland name Wetland type Country = nitrate and NH4 = ammonium, including ammonium-N

.

1 Source: Fisher and Acreman 2004

23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-104 1

23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-105 1

23/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-106 1
Figure 2-4. Percent nutrient reduction as a functio n of loading

. (source: Fisher and Acreman, 2 2004) 3

43/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-107 1

2
On Kent Island, Maryland, a 1.3

- ha restored wetland receives the unregulated inflow s from a 3 14

- - ha agricultural watershed (Jordan et al. 2003). Mos t nutrient removal occurred in the first 4 year, which included a 3 three -month period of decreasing water level in the wetl and. In that year, 5 the wetland removed 59 percent of the TP total P , 38 percent of the TN total N , and 41 percent of 6 the total organic carbon (TOC) C it received. However, in the second year, which la cked a drying 7 period, there was no significant (p > 0.05) net rem oval of T total N or P, although 30 percent of 8 the TO total organic C input was removed. For the entire 2-year period, the wetland removed 25 9 percent of the ammonium, 52 percent of the nitrate, and 34 percent of the organic carbon C it 10 received, but there was no significant net removal of TSS or other forms of N and P. 11
A wetland mesocosm experiment was conducted in east ern North Carolina to determine if 12 organic matter (OM) addition to soils used for in-s tream constructed wetlands would increase 13 NO 3 -N treatment (Burchell et al. 2007). Four batch stu dies, with initial NO 3 -N concentrations 14 ranging from 30 to 120 mg/L, were conducted in 2002 in 21 surface-flow wetland mesocosms. 15 The results indicated that increasing the OM conten t of a Cape Fear loam soil from 50 g/kg to 16 110 g/kg enhanced NO 3 -N wetland treatment efficiency in spring and summe r batch studies, but 17 increases to 160 g/kg OM did not. Increased OM addi tion and biosolids to the Cape Fear loam 18 significantly increased biomass growth in the secon d growing season when compared to no OM 19 addition. That This research indicates that increased OM in the substr ate will reduce the area 20 required for in

- stream constructed wetlands to treat drainage water in humid regions. 213/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-108 A small-scale wetland system was constructed and mo nitored for several years in order to 1 quantify nutrient removal near Steamboat Creek, a t ributary of the Truckee River in Nevada 2 (Chavan et al. 2007). Results indicated seasonal va riations in nutrient removal with 40

– - 75 3 percent of TN total nitrogen and 30

– - 60 percent of TP total phosphorus being removed, with 4 highest removals during summer and lowest removals during winter. In a following study to 5 evaluate the effectiveness of a large-scale wetland
, 10 ten parallel pilot-scale wetland mesocosms 6 were used to test the effects of drying and rewetti ng, hydraulic retention time (HRT), and high 7 N nitrogen loading on the efficiency of nutrient and total suspended solids ( TSS ) removal 8 (Chavan et al. 2008). During increased influent N nitrogen loading (9.5 +/- 2.4 mg/L), 9 manipulated mesocosms functioned as sinks for total nitrogen ( TN ) with removal efficiency 10 increasing from 45 45 +/- 13 percent to 87 +/- 9 percent. The average cha nge in TN 11 concentration was 9.1 +/- 2.2 mg/L. TP removal was associated with TSS removal. 12
Wetlands dominated by submerged aquatic vegetations (SAVs) can may take up nutrients, 13 particularly phosphorus ( P ) , from surface flow with high efficiency. In a 1999

– - 2001 study in 14 South Florida, samples were collected from four sma ll constructed test cells (wetlands) (Gu 15 2008). Test cells receiving higher TP (average = 75 μg ug /L) displayed a removal efficiency of 16 60 percent while test cells receiving lower TP (ave rage = 23 μg ug /L) had a 20 percent removal 17 efficiency. In a similar study, Gu and Dreschel (20 08) evaluated the effectiveness of constructed 18 wetlands from 2002

– - 2004. Test cells receiving higher TP (average = 72 μg ug /L) displayed a 19 removal efficiency of 56

– - 65 percent while test cells receiving lower TP (ave rage = 43 μg ug /L) 20 had a 35

– - 62 percent removal efficiency with a hydraulic load ing rate of 9.27 in/yr. 21
The restoration plan for the Everglades includes co nstruction of large stormwater treatment areas 22 (STAs) to intercept and treat this relatively high nutrient water down to very low total P ( TP ) 23 concentrations (White et al. 2006). One such STA ha s been in operation for approximately 10 24 years yr

and contains both emergent aquatic vegetation (EAV ) and submerged aquatic vegetation 25 ( SAV ) communities. The authors investigated the interact ion of vegetation type (EAV or SAV) 26 and hydrology (continuously flooded or periodic dra wdown) on the P removal capacity in 27 mesocosms packed with peat soil obtained from STA-1 W. The surface water had low TP 28 concentrations with an annual mean of 23 μg ug /L. For SR solubl e reactive P and TP, hydrologic 29 fluctuations had no discernable effect impact on P treatment while vegetation type showed a 30 significant effect impact . Influent SR soluble reactive P decreased by 49 percent for the SAV 31 treatments compared with 41 percent for the EAV tre atments, irrespective of hydrology 32 treatment. The reduction of dissolved organic P was also higher for the SAV treatment, 33 averaging 33 percent, while showing a reduction of 11 percent for the EAV treatments. There 34 was no significant difference in the treatment effi ciency of particulate P across the treatments. 35 The SAV treatments removed 45 percent of TP while E AV removed significantly less at 34 36 percent of TP. By mass calculations, the EAV requir ed 85 percent more P for plant growth than 37 was removed from the water column in 1 year yr compared with only 47 percent for the SAV. 38 Therefore, the EAV mined substantially more P from the relatively stable pe at soil, translocating 39 it into the detrital pool. 40
In an examination of benefits to water quality prov ided by a natural, flow-through wetland and a 41 degraded, channelized wetland situated within the flood-irrigation agricultural landscape of the 42 Sierra Nevada foothills of northern Northern California, Knox et al. (2008) it was found that the 43

non

- degraded, reference wetland significantly improved water quality by reducing loads of 443/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-109 TSS total suspended sediments , nitrate, and E

. scherichia coli on average by 77, 60, and 68 1 percent, respectively ( Knox et al. 2008 ) . Retention of TN, T total N, total P, and soluble re active 2 P ( SRP ) was between 35 and 42 percent of loads entering th e reference wetland. Retention of 3 pollutant loads by the channelized wetland was sign ificantly lower than by the reference wetland 4 for all pollutants except SRP. A net export of sedi ment and nitrate was observed from the 5 channelized wetland. Decreased irrigation inflow ra tes significantly improved retention 6 efficiencies for nitrate, E

. , coli , and sediments in the reference wetland. It is sug gested that 7 maintaining such maintenance of these natural wetlands and regulating regulation of inflow rates 8 can be important aspects of a BMP best management plan to improve water quality in runoff 9 from irrigated pastures. 10



### 4.3 Drainage Water Management 11 Subsurface drainage is a water management practice that is commonly used on many highly 12 productive fields in areas such as the Atlantic Coa stal Plain and the Midwest, but because nitrate 13 carried in drainage water can contribute to water q uality problems in the Chesapeake Bay (as 14 well as some other waterbodies such as the Gulf of Mexico), strategies are needed to reduce the 15 nitrate loads while maintaining adequate drainage f or crop production (Frankenberger
, et al. 16 2006). Drainage is generally achieved with open dit ches or buried pipe accompanied by either 17 gravity-based or pumped outlets. Practices that can reduce nitrate loads on tile-drained soils 18 include (Frankenberger
, et al. 2006) the following : 19

• Fine-tuned fertilizer application rates and timing
, 20

• Winter forage or cover crops
, 21

• Controlled drainage and water table management
, 22

• Ditch management
, 23

• Bioreactors to treat drainage water , and 24

• Constructed wetlands

. 25
Fertilizer management and cover crops are addressed in this document under the heading 26 nutrient management , whereas the other practices are addressed here. I n addition, irrigation 27 tailwater recovery systems are not included in this document. 28
Controlled drainage, is simply the control of surfa ce and subsurface water through use of 29 drainage facilities and water control structures. W ater table management is any combination of 30 the management, control, and/ or regulation of soil-water conditions in the profi le of agricultural 31 soils through the use of water management structure s (e.g., subsurface drains, water control 32 structures, and water conveyance facilities) and st rategies designed specifically for the given site 33 conditions (Brown 1997). Graded ditches are used to collect or intercept excess surface or 34 subsurface water and convey it to an outlet (USDA-N RCS 2008). Ditch management includes 35 managing management of clean

- outs and vegetation within the ditch. Bioreactors a re one form of 36 edge-of-field treatment of drainage water in which the drainage is diverted into a trench filled 37 with wood chips (Minnesota Department Dept. of Agriculture No date Undated ). Constructed 38 wetlands are constructed, shallow, earthen impoundm ents containing hydrophytic vegetation 39 designed to treat both point and nonpoint sources o f water (USDA-NRCS 2002). 403/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-110 In drainage water management, a water control struc ture in a main, submain, or lateral drain is 1 used to manipulate the depth of the drainage outlet (Frankenberger
, et al. 2006). The water table 2 must rise above the outlet depth for drainage to oc cur, as illustrated in Figure 2-5. The outlet 3 depth, as determined by the control structure, is : 4

• Raised after harvest to limit drainage outflow and reduce the delivery of nitrate to ditches 5 and streams during the off-season

. (1 in Figure 2-5) 6

• Lowered in early spring and again in the fall so th e drain can flow freely before field 7 operations such as planting or harvest

. (2 in Figure 2-5) 8

• Raised again after planting and spring field operat ions to create a potential to store water 9 for the crop to use in midsummer

. (3 in Figure 2-5) 10

11

123/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-111 1
Figure 2

- 5

. Drainage Control Structure Source: ( Frankenberger
, et al. 2006; used with permission )
Figure 2-5. Drainage control structure. 2

Implementation Measure: For both new and existing subsurface drainage syst ems, use controlled drainage, ditch management, and bioreact ors as necessary to minimize off-farm transport of nutrients.

I mplementation Measure: For both new and existing subsurface drainage syste ms, use 3 controlled drainage, ditch management, and bioreact ors as necessary to minimize off

- farm 4 transport of nutrients. 5

Practice Effectiveness 6 Controlled Drainage and Water Table 2-Management Pr actice Effectiveness 7

Numerous studies of the effects of controlled drain age have been conducted in North Carolina, 8 the Midwest, and Canada (Table 2- 28 26 ). Flashboard riser-type water level control struct ures 9 installed in tile mains or outlet ditches on modera tely well-drained soils in the Coastal Plain of 10 North Carolina reduced nitrate movement through the ditches by 80

– - 95 percent (from 25–40 11 kg/ha to 1–7 kg/ha) because of due to a reduction in effluent volume with no indication o f 12 increased denitrification in the field (Gilliam , Skaggs et al. 1979). In poorly-drained soils
, a 50 13 percent reduction in nitrate movement through the d rainage ditches was attributed to increased 14 water movement into and through deeper soil horizon s (below 1 m) where denitrification 15 occurred. 16
Variability in the effectiveness of controlled drai nage is reflected in two modeling studies in the 17 coastal plain of North Carolina. In one study, it w as assumed that controlled drainage reduced N 18 by 40 percent
, but only if the slope in the channel is less than 1 percent and where the water table 19 can be kept within 0.9 m meters of the soil surface for 50 percent of the field ar ea (Wossink and 20 Osmond 2001). Long-term modeling of Core Creek usin g the DRAINMOD-N model after 21 calibration on a field-by-field basis with monitori ng data from 4.5 years indicated that controlled 22 drainage could reduce nitrate loads by 10

– - 12 percent, and a combination of controlled drainag e 23 and nutrient management could reduce nitrate loads by 25

– - 33 percent (Smeltz , Evans et al. 24 2005). Modeling predicted that controlled drainage would reduce the drainage outflow by 21.3 253/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-112 percent annually versus conventional drainage (acco unting for 11.5 percent of the reduction in 1 NO 3 -N leaving the watershed), and that there was a pot ential for 30 percent and 75 percent 2 nitrate reductions for cotton or soybeans, respecti vely, as compared to corn. 3

Table 2- 28 2 6 . Measured effectiveness of controlled drainage 4 Reduction vs. reference practice

Location Soils and

crops Study

type Practice Reference practice Discharge NO 3 -N
conc. NO 3 -N

load Source

NC Moderately

well drained soils Field CDflashboard riser UD 85% 85% a 1 Gilliam , Skaggs et al. 1979

NC Poorly drained

soils Field CDflashboard riser UD 50% 50% b 2 Gilliam , Skaggs et al. 1979

IL Field CD UD ≤ 47% c 3 Kalita , Cooke et al. 2007

OH Corn-soybean,

poorly drained Plot CD UD 40% 45% Fausey 2005
Ontario, Canada Corn Field CDS UD 24% 25% d 4 43% Drury , Tan et al. 1996 Ontario, Canada Corn Field CDS-CT UD-MP 49% Drury , Tan et al. 1996 Ontario, Canada Corn Plot CDS UD -8% 41% d 4 36% Ng NG, Tan et al. 2001 Ontario, Canada Corn,

soybeans Plot CDS UD 36% 14% d 4 27% e 5 Tan , Drury et al. 2003 Ontario, Canada Sandy loam Field CDS UD 0% 38% d 4 37%
Ontario, Canada Clay loam Plot CDS UD 50% 32% 66% Tan , Drury et al. 2004

Corn (150 kg N/ha)-soybean (no N), clay loam Field CD UD 44% f 6

Corn (200 kg N/ha)-soybean (50 kg N/ha), clay loam Field CD UD 31% f 6 Drury , Tan et al. 2009

Corn (150 kg N/ha)-soybean (no N), clay loam Field CDS UD 66% f 6 Ontario, Canada

Corn (200 kg

N/ha)-soybean (50 kg N/ha), clay loam Field CDS UD 68% f 6 Drury , Tan et al. 2009

CDS - .05 m UD – - 555% to 58% g,h 7,8 61 %– %

-

84% g 7 0 %–

-

94% g,i 7,9 Ontario, Canada Silt loam, Cornsoybean stripcropping Field CDS - .075m UD – - 583% to

–

- 70% g,h 7,8 52 %– %

-

77% g 7 0 %–

-

30% g,i 7,9 Mejia and

Mandramootoo 1998

NC Various Review j Review 1
0 CD UD 30% k,l 11,12 ≤ 20% l,m 12,
13 45% l,n 12,14 Evans , Gilliam et

al. 19963/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-113 Reduction vs. reference practice

Location Soils and

crops Study

type Practice Reference practice Discharge NO 3 -N
conc. NO 3 -N

load Source

Various Various Review j Review 1
0 CD UD 50% Appelboom and Fouss 2006

Various Various Review j Review 1
0 CD UD 17 %–

- 85% 18 %–

- 85% Skaggs and Youssef

, 2008

KEY: CD = = controlled drainage, UD = = Uncontrolled or traditional or free-tile drainage, CDS = = controlled drainagesubirrigation, CDS-CT = = controlled drainage-subirrigation with conservation tillage, UD-MP = = Uncontrolled or traditional drainage with moldboard plowing.

Notes:

a. FOOTNOTES: 1 Load reduction due solely to discharge reduction; n o change in NO 3 -N concentration. b. 2 Reductions due to increased penetration to deeper soil horizons where denitrification occurred.
c. 3 Nitrate load reductions due mostly to discharge red uctions. Phosphate load reductions of up to 83% d. 4 Flow-weighted mean
e. 5 Also reduced dissolved organic (47%) and dissolved inorganic (54%) P loads f. TN
g. 6 Total N 7 Monitoring only during growing season (April/May-No vember). h. 8 Increased discharge due to lack of management, subi rrigation, and high rainfall, resulting in little s torage for rainfall under CDS. i. 9 No significant difference in 1995 (0%), but signifi cant difference in 1996 (94%, 30%). j. 10 Reviews include some of the field and plot studies shown. k. 11 When managed year-around; <15% reduction during gro wing season. l. 12 Varies with soil type, rainfall, type of drainage, and management intensity

m. 13 TKN concentration increases slightly. Decreases P c oncentration for surface drainage systems, but incr eases P concentration for subsurface systems.

n. 14 NO 3 -N + TKN; TP reduced by 35%

1

Studies in the Midwest measured similar nitrate loa d reductions due to controlled drainage. A 2 review of subsurface drainage in the Midwest reveal ed that drainage water management has 3 achieved load reductions of up to 47 percent and 83 percent for nitrate and phosphate, 4 respectively (Kalita , Cooke et al. 2007). In a replicated field plot experimen t to examine the 5 hydrology, water quality, and crop yield effects impacts of controlled drainage, uncontrolled 6 drainage, and subirrigation drainage on Hoytville s ilty clay soil in Ohio, it was found that 7 controlled drainage during the non-growing season r educed annual flows by 40 percent, yielding 8 a 45 percent reduction in annual nitrate loads from a corn-soybean production system (Fausey 9 2005). 10

In a 3 three -year study on Nicollet loam and silt-loam soils in Iowa, water-table depths of 0.3, 11 0.6, and 0.9 m were maintained in field lysimeters at one site, and water-table depths averaging 12 0.2, 0.3, 0.6, 0.9, and 1.1 m were maintained at a second site to determine the effects of 13 controlled drainage-subirrigation ( CDS ) on nitrate concentrations in groundwater (Kalita a nd 14 Kanwar 1993). The lowest nitrate concentrations in groundwater were observed under the 15 shallow water-table depths, with nitrate concentrat ions in groundwater generally decreasing with 16 increased depths, but average corn yields were 30 p ercent lower under the shallow water-table 17 depths of 0.2 to 0.3 m compared to depths of 0.9 to 1.1 m. 183/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-114 A fairly large number of studies were conducted in Ontario, Canada, to determine the water 1 quality and yield benefits of controlled drainage s ystems. In a 3-year evaluation of controlled 2 drainage

- subirrigation ( CDS ) , conservation tillage, and corn production practic es, annual tile 3 drainage volumes were reduced by 24 percent with CD S compared with traditional drainage 4 (UD) (Drury , Tan et al. 1996). Flow-weighted mean nitrate concentra tion and average annual 5 nitrate loss in tile drainage water were reduced by 25 percent and 43 percent, respectively, when 6 using CDS (7.9 mg/L N, 14.6 kg/ha N) instead of UD. The combination of conservation tillage 7 and CDS reduced annual nitrate losses by 49 percent (11.6 kg/ha N) when compared with 8 conventional moldboard plow tillage and UD. Most (8 8-95 percent) of the nitrate losses from all 9 treatments occurred in the non-cropping period from November through April. The increase in 10 nitrate loss through surface runoff for CDS (1.9 kg /ha N) compared to UD (1.4 kg/ha N) was less 11 than 5 percent of the decrease in loss through tile drainage. 12
Measurements from a plot study on a sandy loam soil in Southwestern Ontario, Canada, showed 13 an 8 percent greater cumulative drainage water volu me from the CDS treatment versus the free14 tile drainage (UD) treatment
, but a 41 percent lower flow-weighted mean nitrate concentration 15 (11.3 mg/L N versus 19.2 mg/L N), a 36 percent lowe r nitrate load (36.8 kg/ha N versus 57.9 16 kg/ha N), and a 64 percent greater average corn yie ld (11.0 Mg/ha versus 6.7 Mg/ha) for CDS 17 versus UD (Ng, Tan et al. 2001). 18
A plot study of a wetland-reservoir system for cont rolled drainage and subirrigation in 19 southwestern Ontario found that a CDS controlled drainage/sub

- irrigation system (CDS) reduced 20 drainage volume by 36 percent, flow-weighted mean n itrate concentration in tile drainage water by 21 14 percent, total nitrate loss by 27 percent (46.3 kg N/ha versus 63.6 kg N/ha), dissolved organic P 22 by 47 percent, and dissolved inorganic P by 54 perc ent compared to a free drainage system (UD) 23 (Tan , Drury et al. 2003). Tile drainage water and surface runo ff water from agricultural fields were 24 routed into a wetland reservoir
, and then recycled back through the CDS to provide subsurface 25 irrigation during times of crop water deficit. Nitr ate uptake by plants and algae in the reservoir and 26 increased corn (91 percent) and soybean (49 percent ) yields contributed to the reductions in nitrate 27 loss for the CDS system. 28
In a comparison of CDS and UD on a 4-ha farm-scale field, CDS did not change total discharge 29 but reduced flow-weighted mean nitrate concentratio n in tile drainage water by 38 percent, 30 reduced total nitrate load by 37 percent, and incre ased both tomato (11 percent) and corn (64 31 percent) yield compared to UD (Tan , Drury et al. 2004). During the same period on a 0.4-ha 32 plot-scale field, CDS reduced total tile drainage v olume by 50 percent, reduced flow-weighted 33 mean nitrate concentration in tile drainage water b y 32 percent, reduced total nitrate load by 66 34 percent, and increased both soybean (17 percent) an d corn (9 percent) yield relative to UD. 35
A study comparing both CD and CDS versus UD at two fertilization rates (N1: 150 kg N/ha 36 applied to corn, no N applied to soybean; N2: 200 k g N/ha applied to corn, 50 kg N/ha applied to 37 soybean) on a clay loam soil in Ontario, Canada, do cumented that CD and CDS reduced N loads 38 from tile drainage by 44 and 66 percent, respective ly, relative to UD at the N1 rate, and by 31 39 and 68 percent, respectively, at the N2 rate (Drury , Tan et al. 2009). The N concentrations in tile 40 flow events with the UD treatment exceeded Ontario’ s provisional long-term aquatic life limit 41 for freshwater (4.7 mg N L-1) 72 percent and 78 per cent of the time at the N1 and N2 rates, 42 respectively, but only 24 percent and 40 percent, r espectively, with CDS. Crop yields from CDS 433/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-115 were increased by an average of 2.8 percent relativ e to UD at the N2 rate, but were reduced by 1 an average of 6.5 percent at the N1 rate. 2
A CDS system managed at a depth of 0.050 m reduced total drain discharge over two growing 3 seasons by 42 percent versus UD in a field study in eastern Ontario (Mejia and Mandramootoo 4 1998). Growing-season mean nitrate concentrations i n drainage water were reduced by CDS at 5 both a depth of 0.050 m (61

– - 84 percent) and a depth of 0.075 m (52

– - 75 percent) versus UD. 6 Because of high rainfall and failure to manage the CDS under the wet conditions, discharge was 7 over 5 times greater in 1995 under CDS at each dept h, resulting in no significant change in 8 nitrate load. In 1996, however, growing-season nitr ate loads were reduced by 94 percent and 30 9 percent by the 0.050 m and 0.075 m CDS, respectivel y. 10
Monitoring over 2 years of four replicate plots eac h of surface runoff, CD at 1.1m below the soil 11 surface, and CDS at 0.8 m in Baton Rouge showed that 67 percent of the annu al nitrate loss in 12 tile drainage for the CD and CDS systems occurred d uring the 150-day growing season (Grigg
, 13 Southwick

et al. 2003). There were no statistical difference s between the surface, subsurface, or 14 total nitrate loads from the CD and CDS systems. 15
Compilations and reviews of literature on controlle d drainage have yielded largely consistent 16 findings. Based on approximately 125 site-years of data collected at 14 locations in eastern North 17 Carolina (Evans , Gilliam et al. 1996): 18

• Controlled drainage, when managed all year, reduces total outflow by approximately 30 19 percent compared to uncontrolled systems, although outflows vary widely depending on 20 soil type, rainfall, type of drainage system and ma nagement intensity. For example, control 21 only during only the growing season typically reduces outflow by les s than 15 percent. The 22 effect of controlled drainage on peak outflow rates varies seasonally. Drainage control 23 reduces peak outflow rates during dry periods (summ er and fall) but can may increase peak 24 outflow rates during wet periods (winter and spring ), depending on the control strategy. 25

• Drainage control has little net effect on TN total nitrogen and P phosphorus concentrations 26 in drainage outflow. Controlled drainage can may reduce NO 3 -N concentrations in 27 drainage outflow by up to 20 percent , but total Kjeldahl nitrogen ( TKN ) concentrations 28 are somewhat increased. Controlled drainage tends t o decrease P phosphorus 29 concentrations on predominately surface systems but has the opposite effect on 30 predominately subsurface systems. Seasonal variatio ns can may also occur, depending on 31 rainfall, soil type, and the relative contribution of surface or subsurface drainage to total 32 outflow. 33

• Controlled drainage reduces N nitrogen and P phosphorus transport at the field edge, 34 primarily because of the reduction in outflow volum e. In 14 field studies, drainage 35 control reduced the annual transport of TN total nitrogen (NO 3 -N and TKN) at the field 36 edge by 10 kg/ha, or 45 percent , and TP total phosphorus by 0.12 kg/ha, or 35 percent. 37 Again, the reductions at individual sites were infl uenced by rainfall, soil type, type of 38 drainage system, and management intensity. 39

In a broader review of methods to reduce nitrate in drainage water, it was estimated that the 40 potential for nitrate load reduction with controlle d drainage is approximately 50 percent 41 (Appelboom and Fouss 2006). Skaggs and Youssef (200 8) reported a wide range of discharge 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-116 reduction (17

– - 85 percent) and nitrate load reduction (18

– - 85 percent) in a summary of studies 1 conducted in North Carolina NC , Ohio, Sweden, and Canada. The authors note that c ontrolled 2 drainage increases evapotranspiration (ET), surface runoff, and deep and lateral seepage, with 3 ET accounting for only 8

– - 15 percent of the reduction in subsurface drainage compared to 4 conventional drainage and seepage effects dependent on the size and boundary conditions of the 5 fields under controlled drainage. The effects of si ze and boundary condition on discharge are 6 illustrated by the different findings for field and plot studies in Canada (Tan , Drury et al. 2004). 7 Reductions in nitrate concentration from due to controlled drainage were minimal in most 8 studies, so it is important to know what happens to the nitrate in the seepage water. Evidence 9 indicates that in poorly or very poorly drained soi ls
, the nitrate is reduced at depths greater than 1 10

m meter

or so, providing effective reduction of N losses t o the environment. 11
Ditch Management Practice Effectiveness 12 In a 2-year study of two experimental farm drainage ditches serving land planted in a summer 13 row crop/winter fallow sequence in northern Mississ ippi, monthly baseflow and stormflow (28 14 storms) regression results indicated that drainage ditches reduced nitrate and ammonia over the 15 length of the ditch for both growing and dormant se asons (Kroger , Holland et al. 2007). 16 Maximum farm effluent dissolved inorganic N load, d efined as the highest load attained spatially 17 within the drainage ditch as a result of the combin ation of surface and subsurface flow processes, 18 was reduced by an average of 57 percent by the ditc hes. 19
Sediment from two similar drainage ditches in the A tlantic coastal plain were sampled (0

– - 5 cm) 20 after one of the ditches had been dredged, removing fine-textured sediments (clay = 41 percent) 21 with high organic matter content (85 g/kg) and expo sing coarse-textured sediments (clay = 15 22 percent) with low organic matter content (2.2 g/kg) (Shigaki , Kleinman et al. 2008). Laboratory 23 testing in a flume revealed that under conditions o f low initial P concentrations, sediment from 24 the dredged ditch released 13 times less P to the w ater than did sediment from the ditch that had 25 not been dredged, but the sediments from the dredge d ditch removed 19 percent less P from the 26 flume water when it was spiked with dissolved P to approximate long-term runoff 27 concentrations. Irradiation of sediments to destroy microorganisms revealed that biological 28 processes accounted for up to 30 percent of P uptak e in the coarse-textured sediment of the 29 dredged ditch and 18 percent in the fine-textured s ediment of the undredged ditch. 30
Because vegetation in ditches increases sediment re tention, cycles nutrients, and promotes the 31 development of soil structure, it is proposed that management procedures that encourage ditch 32 vegetation, such as targeted clean-outs and gradual inundation, may increase the stability and 33 ecosystem services of ditch soils (Needelman , Ruppert et al. 2006). A study in Florida to 34 evaluate P characteristics of agricultural ditch so ils in the Lake Okeechobee Basin found that in35 ditch management practices, such as using the use of soil amendments or controlled drainage, 36 could be useful to reduce P loss from ditch soils ( Dunne , McKee et al. 2006). 37
Bioreactors Effectiveness 38

Several studies have measured the effectiveness of bioreactors in removing nitrate and other 39 contaminants from agricultural drainage water (Tabl e 2- 29 27 ). 403/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-117 Table 2- 29 2 7 . Measured nitrate removal rates for bioreactors 1 Removal (%)

Location Practice Flowthrough rate (L/min) NO 3 -N

conc. NO 3 -N

load Source
IA Wood-chip denitrification walls 65% a 1 61%-68% a 1 Jaynes , Kaspar et al. 2004 Wood chip bioreactor 38% MN Wood chip bioreactor plus CD 88% Thorstensen No date Denitrification reactor using wood particles—Lateral Flow Design 7.7 32% Ontario, Canada Denitrification reactor using wood

particles—Upflow Design 7.8 52% van Driel
, Robertson et al. 2006

Ontario, Canada In-ditch wood chip bioreactor 24 78% Robertson and Merkley 2009 Ontario, Canada Subsurface wood mulch

bioreactor (pilot scale) 0.6

– - 1.4 58% Robertson
, Blowes et al. 2000 Ontario, Canada 200-L fixed-bed bioreactors with

sand, tree bark, wood chips, leaf compost (pilot scale) 0.007

– - 0.042 99% Blowes
, Robertson et al. 1994 Various Constructed bioreactors (review

article) b 2 60 %–

- 90% Appelboom and Fouss 2006
Various Constructed bioreactors (review

article) b 2 60 %–

- 100% Kalita , Cooke et al. 2007

Notes:

a. FOOTNOTES: 1 Reduction compared to uncontrolled drainage. b. 2 Reviews include some of the other studies shown.
2
In an Iowa study comparing several tile and croppin g modifications for reducing nitrate in tile 3 drainage versus the nitrate concentration in draina ge from a UD treatment (tile at 1.2 m), it was 4 found that denitrification walls (DW) reduced the n itrate concentration in tile drainage by an 5 average of 65 percent and the tile drainage N load by 61

– - 68 percent compared to UD (Jaynes, 6 Kaspar et al. 2004). 7
A bioreactor (24.4 -m meters long x 0.76 -m meters wide x 1.5 -m meters deep) in Minnesota that 8 is paired with a CD system has reduced TSS total suspended solids by 74 percent, TP by 78 9 percent, nitrate by 38 percent, and E. coli Coli by 52 percent in drainage water from 3.2 hectares 10 of farmland (Thorstensen No date). Combined, the bi oreactor and CD reduced nitrate and TP in 11 the drainage water by 88 percent. 12
Two denitrification reactor designs using fine and coarse wood particles, a lateral flow design 13 and an upflow design, were tested under baseflow co nditions in southern Ontario, the former 14 over a 26-month period on drainage from a cornfield , and the latter over a 20-month period on 15 drainage from a golf course (van Driel , Robertson et al. 2006). Removal by the reactor at the 16 cornfield site averaged 3.9 mg N/L at an average fl ow-through rate of 7.7 L/min and an average 17 influent nitrate concentration of 11.8 mg N/L. With an average flow-through and influent nitrate 183/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-118 concentration of 7.8 L/min and 3.2 mg N/L, respecti vely, removal by the reactor at the golf 1 course site averaged 1.7 mg N/L. Mass balance calcu lations indicate that carbon consumption 2 from denitrification was < 2 percent per year, showing the potential for the r eactors to operate for 3 a number of years without the need for media replen ishment. 4

A 40-m 3 woodchip bioreactor was trenched into the bottom o f an existing agricultural drainage 5 ditch in Ontario, Canada, with flow induced through the reactor by construction of a gravel riffle 6 in the streambed (Robertson and Merkley 2009). Over the first 1.5 years of operation, a mean 7 influent nitrate concentration of 4.8 mg/L was redu ced to 1.04 mg/L at a mean reactor flow rate 8 of 24 L/min. A series of flow-step tests, facilitat ed by an adjustable height outlet pipe, 9 demonstrated that nitrate mass removal generally in creased with increasing flow rate. Silt 10 accumulation reduced reactor flow rates over time, but design modifications were implemented 11 to address the problem. 12
In a 1-year pilot-scale study, two 200-L fixed-bed bioreactors containing coarse sand and organic 13 carbon (tree bark, wood chips
, and leaf compost) were used to treat NO 3 contamination from 14 agricultural runoff (Blowes , Robertson et al. 1994). At inflow rates of 10

– - 60 L/day, NO 3 -N 15 concentrations of 3–6 mg/L in farm-field drainage t iles were reduced by the reactors to less than 16 0.02 mg/L. 17
In Ontario, a pilot-scale assessment of a plywood-f ramed (1.9 m 3 ) subsurface reactor filled with 18 coarse wood mulch documented a 58 percent removal o f nitrate from farm drainage water 19 influent at hydraulic loading rates ranging from 80 0 to 2,000 L/day (Robertson , Blowes et al. 20 2000). Nitrate consumption rates were temperature d ependent, ranging from 5 mg/L N per day at 21 2

– - 5 °C, to 15

– - 30 mg/L N per day at 10

– - 20 °C
, but did not deteriorate over the 7-year 22 monitoring period. Mass-balance calculations of car bon consumption indicated that the reactor 23 could perform well for at least a decade without ca rbon replenishment. 24
In a review of methods to reduce nitrate in drainag e water, it was estimated that the potential for 25 nitrate reduction is 60 to 90 percent for construct ed bioreactors (Appelboom and Fouss 2006). 26

A review of bioreactors in the Midwest found that t hey could reduce nitrate levels by 60

– - 100 27 percent (Kalita , Cooke et al. 2007). In addition, the authors identified the following advantages 28 of bioreactors: 29

• They use proven technology
, 30

• They require no modification of current practices 31

• No land needs to be taken out of production 32

• There is no decrease in drainage effectiveness over time 33

• They require little or no maintenance , and 34

• They can last for up to 20 years

. 35
Constructed Wetlands Effectiveness 36 In a review of methods to reduce nitrate in drainag e water, it was estimated that the potential for 37 nitrate reduction is 37

– to 65 percent for natural/constructed wetlands, with u p to an additional 38 18 percent if a berm is used in creation of the wet land (Appelboom and Fouss 2006). A 393/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-119 combination of controlled-drainage, constructed wet land, and in-stream denitrification could 1 possibly result in more than 75 percent nitrate removal before prior to release to larger streams or 2 other surface waters. 3

Measurement over 3 three years of N nitrogen removal rates in three large (0.3 to 0.8 ha, 1200 to 4 5
, 400 m 3 in volume) constructed wetlands treating tile drai nage from corn and soybean fields in 5 southern Illinois indicated TN total nitrogen removal of 37 percent in the wetlands (Kovacic
, 6 David et al. 2000). The wetlands also decreased NO 3 -N concentrations of inlet water by 28 7 percent, and coupling the wetlands with a 15.3-m bu ffer strip between the wetlands and the river 8 removed an additional 9 percent of the tile NO 3 -N, increasing the N removal efficiency to 46 9 percent. T T otal P removal was only 2 percent during the 3- year yr period, with highly variable 10 results in each wetland and year. 11
Two agricultural runoff wetlands, W1 (area 0.16 ha, volume 660 m 3 ) and W2 (area 0.4 ha, 12 volume 1780 m 3 ), intercepting surface and tile drainage in the La ke Bloomington, Illinois, 13 watershed, achieved a mass NO 3 -N retention of 36 percent (Kovacic , Twait et al. 2005). 14 Wetlands W1 and W2 reduced overall volume-weighted nitrate concentrations by 42 percent and 15 31 percent, respectively. Combined P mass retention was 53 percent, and combined total organic 16 carbon ( TOC ) mass retention was 9 percent. 17
The integration of constructed wetlands within agri cultural Wetland Reservoir Subirrigation 18 Systems (WRSIS) is being evaluated at three demonst ration sites in Ohio (Allred
, et al. 2008). 19 Each WRSIS is composed comprised of a constructed wetland, a water storage reservoi r, and a 20 network of subsurface pipes used at different times to either drain or irrigate crops through the 21 root zone. WRSIS can be operated hydraulically in a closed

- loop mode most of the time with 22 off

- site water release restricted, creating opportuniti es to route agricultural field runoff and 23 subsurface drainage to the wetland for water treatm ent, and then to the storage reservoir where it 24 is held until needed to subirrigate field crops dur ing dry times parts of the growing season. Water 25 quality measurements have been tabulated for 2003 t hrough 2007, and two of the three WRSIS 26 wetlands have shown substantial effectiveness in re moving suspended sediment, nitrate, and 27 TN total nitrogen

. 28

Practice Costs 29 Dual-purpose drainage/subirrigation systems provide for drainage, controlled drainage, and 30 subirrigation (Evans and Skaggs 1996). Systems desi gned primarily for drainage might may need 31 to be redesigned or managed more intensively to ser ve as dual-purpose systems. The three major 32 expenses of installing and operating a drainage and subirrigation system are the cost of a water 33 supply, underground tubing installation, and land g rading (Evans , Skaggs et al. 1996). If 34 subirrigation is not part of the system, a water su pply is not needed, but increased yields realized 35 with subirrigation can contribute to nitrate reduct ions because of due to increased crop uptake. 36 On the basis of Based on estimates for 1996, water supply ponds sufficient t o irrigate 37 approximately 40 ha would cost about $68,000 –$

- $ 81,500 in 2008 dollars, but other water 38 supplies (e.g., stream) could be much cheaper. Unde rground tubing installation costs are 39 generally the largest single expense, varying with the total footage, tubing diameter, installation 40 method, and whether filter material is used. The am ount of tubing needed depends on the 41 hydraulic conductivity of the soil, with spacing ra nging from 40 to 100 feet in North 42 Carolina. NC. The cost of 10-cm tubing ranges from about 76 cent s to just over $1 one dollar per 433/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-120 m eter , with filter material adding another 31 to 53 cent s per m eter . The cost to install 1 underground tubing depends on the specific job, but can range from about $1.34/ m meter to 2 $2.23/ m meter

for 10-cm tubing. Using Based on the estimates for 1996, total cost to install tubi ng 3 at 10- m meter

spacing is about $2,660/ha, whereas the cost for 3 0- m meter spacing is about 4 $880/ha. Land grading could add $170 to $850/ha to the cost, and the cost of control structures 5 ranges from about $400 to more than $4,000. Finally , installation generally requires field borders 6 to stabilize open ditches at a cost of about $100 p er production hectare. 7 A cost analysis for controlled drainage in the lowe r coastal plain of North Carolina assumed the 8 need for a surface drainage system of 0.9- to 1.5-m eter -deep open ditches, a flashboard riser 9 installed in the collector canal, a corrugated meta l pipe culvert for an outlet, and concrete to 10 stabilize the riser (Wossink and Osmond 2001). It w as assumed that there would be no 11 installation and maintenance costs for ditches beca use they were part of the pre

- existing 12 condition. On the basis of Based on a land slope of 0.1 to 0.4 m /km eters per kilometer , it was 13 assumed that there would be one structure per mile in the canal on a 0.6- to 0.75- m meter contour 14 interval, meaning that one control structure in the main canal would serve 130 hectares. It was 15 also assumed that under controlled drainage soybean s and cotton yields would increase by 2 16 percent or more, corn yields would increase by 5 pe rcent or more, and wheat and tobacco yields 17 would not increase. Installation costs for controll ed drainage were estimated to be $57.20/ha 18 (2008 dollars), while annual maintenance was estima ted at $3.75/ha, and benefits from yield 19 increases were estimated at $6.03/ha to $33.12/ha. Assuming cost-share availability of about 20 $45/ha, the authors concluded that cost-shared cont rolled drainage was financially practical for 21 the lower coastal plain of NC. 22
In a demonstration plot in Minnesota, the costs ass ociated with controlled drainage included 23 drainage control structures, design, installation, extra pipe and installation, totaling about $35/ha 24 for a 65-ha field (Binstock 2009). Tile spacing was set at 22.8 m eters , using 10-cm diameter 25 laterals on a slope of just under 1 percent. It has been estimated that drainage management 26 systems cost about $50 to $500/ha more than convent ional drainage systems (Newby 2009). 27
Water control structures for drainage water managem ent cost from about $530 to $2,100 (2008 28 dollars) depending on height, size of tile, structu re design, manufacturer, and whether it is 29 automated (Frankenberger
, et al. 2006). Installation costs for structures ar e about $215 for basic 30 structures, increasing with size and complexity. As suming flat terrain, a single structure could 31 serve 8 hectares at a cost of $70 to $265 per ha hectare

. 32
Both a lateral flow design and an upflow design bio reactor tested in Ontario were successful in 33 achieving maintenance-free operation during all sea sonal conditions, including unassisted startup 34 after drought and freeze periods (van Driel , Robertson et al. 2006). Construction cost per unit 35 N nitrogen removal for bioreactors designed to manage baseflo w conditions are expected to be 36 similar to the cost for constructed wetlands, but l ess land is required for the bioreactors. 37
A woodchip bioreactor (38 m meters long by 1.8 m meters deep by 0 .6 –0

- .9 m meters wide) in 38 Minnesota cost approximately $3,200 to construct (M innesota Department Dept . of Agriculture 39 No date Undated ). Control structures cost $1,500, trenching cost $ 1,100, and $600 was spent on 40 woodchips. Serving approximately 3.2 ha, the biorea ctor cost is about $990/ha and is expected to 41 work for about 20 years. The cost of a 60- m meter bioreactor ranges from about $2,900 to $4,300 42 depending on materials and design (Morrison 2008). 433/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-121 

### 4.4 Animal Feeding Operations 1

Animal feeding operations Feeding Operations (AFOs) congregate animals, feed, wastes, and 2 production operations on a small land area. Water p ollution by animal production can be caused 3 by leaching and runoff of organic matter, N, P, and pathogens from animal congregation areas or 4 other parts of the facility before wastes are other wise contained or managed (see Section 2). Key 5 strategies for edge of field trapping and treatment of AFO runoff include vegetated filter strips 6 ( VFS ) and other techniques to capture runoff from feedlo ts, barnyards, and other facility areas 7 and remove sediment, nutrients, and other pollutant s before delivery to surface waters. 8
Water quality effects impacts from AFOs using grazing and pasture land include n utrients and 9 pathogens in runoff from areas of waste deposition and soil loss from areas of degraded 10 vegetation cover. While livestock exclusion (see Se ction 2) and pasture management (see 11 Section 3.4 X ) are often the main approaches to managing water q uality effects impacts from 12 grazing livestock, non-grazed, vegetated buffer str ips or other edge-of-field practices are often 13 recommended to protect waterbodies from sediments a nd nutrients in runoff from grazed 14 pastures. 15

Implementation Measure: Manage all livestock production runoff and runoff from grazing and pasture areas to minimize off-farm transport of nutrients and sed iment. Implementation measure : Manage all livestock production runoff, as well as runoff from 16 grazing and pasture areas to minimize off

- farm transport of nutrients and sediment

. 17

Practice Effectiveness 18 Production Area Effectiveness 19
Based on a review of the literature, Koelsch et al. (2006) presented the following concl usions 20 about the application of vegetative treatment syste ms (VTS) to manage runoff from open lot 21 livestock production areas: 22

• The pollutant reduction resulting from a VTS is bas ed up on two primary mechanisms: ( 1) 23 sedimentation, typically occurring within the first few meters of a VTS, and ( 2) 24 infiltration of runoff into the soil profile. Syste m design based up on sedimentation and 25 infiltration is necessary to achieve a required per formance level for concentrated AFO 26 ( CAFO ) application. 27

• Critical design factors specific to attaining high levels of pollutant reduction within a 28 VTS include pre

- treatment, sheet flow, discharge control, siting, a nd sizing. Critical 29 management factors include maintaining maintenance of a dense vegetation stand and 30 sheet flow of runoff across VTA as well as minimizing minimization of nutrient 31 accumulation. 32
The authors report numerous pollutant removal rates for a variety of VTS under a broad range of 33 circumstances. In general, the literature reports 7 0

– - 90 percent TS removal, 80 percent N 34 removal, 70 percent P removal, and 77 percent fecal coliform removal from CAFO runoff treated 35 by VTS. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-122 In Nebraska, Woodbury et al. (2000
, and 2002) tested a flat-bottom terrace to collect runof f 1 from a beef feedlot to provide temporary liquid sto rage , and accumulate settable solids, while 2 distributing the liquid fraction uniformly across a VFS vegetative filter strip . No runoff left the 3 VFS vegetative filt er strip , indicating that the basin discharge was used utilized for grass 4 production. In a follow-up study, Woodbury et al. ( 2003) reported that the system reduced the 5 cumulative mass of TSS (80 percent), VSS (67 percen t), and COD (59 percent) 6
Kim et al. (2003) studied flow and P transport thro ugh a VFS vegetated filter strips receiving 7 milkhouse wastewater and barnyard runoff from two N ew York dairy farms. Although 33 m–40 8 m VFS eventually reduced soluble P to < 0.2 mg/L, P was less effectively removed where soil 9 saturation occurred. Wastewater entering a VFS shou ld be distributed uniformly to avoid soil 10 saturation. 11
In Montana, Fajardo et al. (2001) reported on the e ffectiveness of VFS using tall fescue in 12 treating runoff from livestock manure stockpiles. R unoff NO 3 -N concentrations were reduced by 13 97–99 percent by a VFS. Coliform bacteria counts we re reduced by 64–87 percent, although 14 bacteria counts in runoff leaving the VFS remained elevated, even for treatments not receiving 15

manure. 16

VFS Vegetative filter st rips were effective in removing a broad range of consti tuents from a 17 Kansas beef feedlot runoff pretreated by a settling basin (Mankin and Okoren 2003). The first 30 18 m provided most or all of the reductions found within the 150-m VFS VFSs studied: reductions 19 averaged 85 percent of inflow water, 85 percent of sediment, 77 percent of N, and 84 percent of 20 P. Fecal bacteria removal by the VFS VFSs was on the order of 1-log: reductions at 30 m rang ed 21 from 84 percent for FC and FS to 91 percent for E. coli

. 22

In Illinois
, Trask et al. (2004) reported that a VFS can be a B MP for controlling Cryptosporidium 23 in runoff from animal production facilities. The ve getative surface was very effective in reducing 24 C. parvum in surface runoff; for all slopes and rainfall int ensities, recovery of C. parvum oocysts 25 was considerably less from a vegetated surface than from the bare-ground conditions. For a 25.4 26 mm/h rainfall event, recovery of oocysts in overlan d flow from the VFS varied from 0.6 to 1.7 27 percent, while those from the bare ground condition varied from 4.4 to 14.5 percent. For the 63.5 28 mm/h rainfall, the recovery percentages of oocysts varied from 0.8 to 27.2 percent from the VFS, 29 and 5.3 to 59 percent from bare-ground conditions. 30
Hubbard et al. (2007) tested the performance of gra ss-forest vegetated buffers in assimilating N 31 from overland flow application of swine lagoon effl uent in Georgia. The buffers approximated 32 60 m in length by 90 m in width. The upper 10 m of each buffer was in grass, while the 33 downslope area was in mature or newly planted pines . Shallow groundwater under the buffers 34 showed nitrate (NO 3 -N) concentrations 20–30 m downslope to be <10 mg/L . On those these 35 buffers, NO 3 -N concentrations in shallow groundwater were near background levels 5 five years 36 after wastewater application commenced. The ratio o f buffer area width to wastewater 37 application area width on the landscape should be a t least 1:1. 38
In Kansas, Mankin et al. (2006) quantified beef cat tle feedlot runoff quality, particularly during 39 unstocked conditions, and evaluated reductions of f ecal bacteria and nutrients in VFS vegetative 40 filter strips treating feedlot runoff. Events when few or no cat tle were present averaged 17 41 percent of T the total N (20 mg/L), 14 percent of T the total P (6 mg/L), and 2 percent of the fecal 423/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-123 coliforms (2.1 x 10 4 cfu 100/mL) of events with cattle present. Measure d concentration 1 reductions from all events and VFS vegetative filter strips averaged 77 percent (fecal coliforms), 2 83 percent ( E. coli ), 83 percent (fecal streptococci), 66 percent ( T total N), and 66 percent ( TP). 3 VFS total P). Vegetative filter strips allowed no discharges for > 90 percent of feedlot runoff 4 events at the sites with the ratio of VFS vegetative filter strip : drainage area > 0.5. 5 Gilley et al. (2008) compared nutrient transport in runoff from beef feedlots in Nebraska with 6 loose manure surfaces versus vs. compacted surfaces. No significant differences in feedlot soil 7 characteristics or nutrient transport in runoff wer e found between loose and compacted surfaces. 8 However, concentrations of E. coli were significantly greater in runoff from the loos e surface 9 feedlots. 10
In Finland, Narvanen et al. (2008) tested a ferric sulfate dosing system to treat runoff from horse 11 paddocks; runoff was then discharged into a sedimen tation pond and sand filter. Dissolved P was 12 reduced by 95 percent, T total P by 81 percent. 13
Robertson and Merkley (2009) demonstrated an in-str eam bioreactor using woodchips to 14 promote denitrification of agricultural drainage in Ontario, Canada. Over the first 1.5 years of 15 operation, mean influent NO 3 -N of 4.8 mg/L was attenuated to 1.04 mg/L (a 78 pe rcent 16 reduction) at a mean reactor flow rate of 24 L/min. When removal rates were not nitrate-limited, 17 areal mass removal ranged from 11 mg N/m 2 /h at 3 o C to 220 mg N/m 2 hr at 14°C, exceeding 18 rates reported for some surface-flow constructed we tlands by a factor of about 40. 19

Table 2- 30 28 . Summary of reported practice effects resulting fr om VFS treatment of AFO runoff

. 20

Location Study

type Practice Practice effects Source Various Review Vegetated

treatment systems Literature reports removals of ~70 %–

- 90% TS, ~80%

N, ~70% P, and ~77% fecal coliform from CAFO runoff treated by diverse vegetated treatment systems. Koelsch et al. 2006

NE BMP Settling

basin/VFS No runoff left the VFS vegetative filter strip treating

beef feedlot runoff; the system reduced the cumulative mass of TSS (80%), VSS (67%), and COD (59%) Woodbury et al. 2000
, 2002, 2003

NY BMP VFS Although 33–40 m VFS treating milkhouse waste and barnyard runoff reduced soluble P to < 0.2mg/L in most cases; P was less effectively removed in the areas where soil saturation occurred. Kim et al. 2003

MT BMP VFS VFS treating runoff from manure stockpiles reduced NO 3 -N concentrations by 97 %–

- 99% and coliform bacteria counts by 64 %–

- 87% a 1 Fajardo et al. 2001

KS BMP Settling

basin, VFS Reductions averaged 85% of inflow water, 85% of

sediment, 77% of N, and 84% of P. Bacteria reductions at 30 m ranged from 84% for FC and FS to 91% for E. coli

. The first 30 m provided most or all of the reductions. Mankin and Okoren 20033/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-124 Location Study

type Practice Practice effects Source IL BMP VFS vs. bare

soil Fewer Cryptosporidium oocysts were passed in overland flow from a vegetated surface than from th e bare-ground conditions. For a 25.4 mm/h rainfall event, oocyst recovery from the VFS were 0.6 -1.7%, vs. 4.4 to 14.5% from bare ground. For the 63.5 mm/h rainfall, the recovery percentages of oocysts varied from 0.8 % –27.2% from the VFS, and 5.3 %

– 59% from bare ground. Trask et al. 2004

GA BMP Grass-forest

buffer b buffer 2 Shallow groundwater under the buffers showed

nitrate (NO 3 -N) concentrations 20–30 m downslope to be <10 mg/L. On these buffers, NO 3 -N concentrations in shallow groundwater were near background levels 5 five years after wastewater application began. commenced. Hubbard et al. 2007

KS BMP VFS, feedlot

stocking rate Runoff when few or no cattle were present averaged

17% of the T total N, 14% of the T total P, and 2% of the fecal coliforms vs. events with cattle present. Concentration reductions averaged 77% (fecal coliforms), 83% ( E. coli ), 83% (fecal streptococci), 66% ( T total N), and 66% ( T total P). Mankin et al. ( 2006

NE BMP Feedlot

surface No significant differences in nutrient transport in

runoff were found between loose and compacted feedlot surfaces. E. coli counts were significantly greater in runoff from the loose surface feedlots. Gilley et al. 2008

Finland BMP Ferric

sulfate, sand filter Dissolved P was reduced by 95%, T total P by 81%

using a ferric sulfate dosing system and sand filte r to treat runoff from horse paddocks Narvanen et al. 2008

Ontario, Canada BMP Woodchip

bioreactor Treating AFO drainage, NO 3 -N was attenuated to

1.04 mg/L (78% reduction); areal mass removal ranged from 11 mg N/m 2 /h at 3 ° o C to 220 mg N/m 2 hr at 14 °C, exceeding rates reported for some surfaceflow constructed wetlands by a factor of about 40. Robertson and Merkley 2009

Notes:

a. Footnotes:

1 Bacteria counts in runoff leaving the VFS remained elevated, even for treatments not receiving manure b. 2 Upper 10 m in grass, 20-30 m downslope in trees
1 Buffer/filter strips treating pasture runoff 2 Sotomayor-Ramirez et al. (2008) tested 10

- and 20

- m grassed filter strips treating runoff from 3 grazed pasture amended with dairy manure sludge in Puerto Rico. Filter strips reduced TP and 4 dissolved P concentrations by 29 percent and 32 per cent at 10 m, and by 57 percent and 49 5 percent at 20 m, respectively. A 27 percent decrease in TKN conce ntration was observed in one 6 field as a result of the 20-m filter strip. 7 Tate et al. (2000) evaluated the potential water qu ality improvements from 10

- m buffer strips on 8 irrigated land in California. The 10

- m buffer did not significantly reduce concentration s and 9 load of NO 3 -N in runoff from sprinkler and flood irrigated pas tures. The buffer also failed to 103/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-125 reduce T Total P concentration under either irrigation schemes, or T Total P and TSS load under 1 sprinkler irrigation. 2
The presence of a vegetated buffer of any size (fro m 1 to

– 25 m), generally reduced median fecal 3 coliform bacteria concentrations and loads in runof f from Oregon pasture land by more than 99 4 percent (Sullivan et al. 2007). 5
Other practices treating pasture runoff 6 Tanner et al. (2005) reported on the performance of a surface-flow constructed wetland 7 (occupying ~1 percent of the catchment area) treatin g subsurface drainage from rain-fed, dairy 8 cattle grazed pasture in New Zealand. TN mass remov al efficiency was 79 percent (841 g/m 2 per 9 year) the first year
, but declined to 21 percent (40 g/m 2 per year) in the second year, associated 10 with changes in the magnitude, speciation and seaso nal pattern of N export from the catchment. 11 TP export rose by 101 percent (5.0 g/m per year) af ter passage through the wetland in the first 12 year , but decreased by 12 percent (0.2 g/m 2 per year) in the second year. The results show tha t 13 constructed wetlands composing comprising similar to 1 percent of catchment area can markedly 14 reduce N export via pastoral drainage
, but could may be net sources of NH 4 -N, DRP and TP 15 during establishment. 16
Knox et al. (2008) examined benefits to water quali ty provided by a natural, flow-through 17 wetland receiving runoff from irrigated pasture in California. The wetland reduced loads of TSS 18 (77 percent), nitrate (60 percent), and E. coli (68 percent). Retention of TN, T total N, total P, and 19 SR so luble reactive P was between 35 and 42 percent of loads entering t he wetland. 20

Table 2- 31 29 . Summary of reported practice effects resulting fr om buffer/wetland treatment of 21 pasture runoff

. 22

Location Study

type Practice Practice effects Source Puerto Rico BMP Grassed

filter strips Filter strips treating runoff from grazed pasture r educed

TP and dissolved P concentrations by 29% and 32% at 10 m, and by 57% and 49% at 20 m, respectively. A 27% decrease in TKN concentration was observed in one field as a result of the 20-m filter strip SotomayorRamirez et al. 2008

CA BMP Buffer 10

- m buffer did not significantly reduce concentration s and load of NO 3 -N in runoff from sprinkler and flood irrigated pastures. The buffer also failed to reduc e T Total P concentration under either irrigation schemes,
or T Total P and TSS load under sprinkler irrigation Tate et al. ( 2000

OR BMP

plots Vegetated

buffer The presence of a vegetated buffer of any size (fro m 1

to

– 25 m) reduced median fecal coliform bacteria concentrations and loads in runoff by more than 99%

. Sullivan et al. 2007

New Zealand BMP Constructed

wetland Surface-flow constructed wetland (occupying ~1% of

catchment area) treating subsurface drainage dairy cattle grazed pasture: TN mass removal efficiency w as 79% (841 g/m 2 per year) the first year

, but declined to 21% (40 g/m 2 per year) in the second year. TP export rose by 101% (5.0 g/m per year) after passage throu gh the wetland in the first year

, but decreased by 12% (0.2 g/m 2 per year) in the second year. Tanner et al. 20053/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-126 CA BMP Natural

wetland Wetland receiving runoff from irrigated pasture red uced

loads of TSS (77%), nitrate (60%), and E. coli (68%). 35 % to 42% of TN, T total N, total P, and SR soluble reactive P loads entering the wetland were retained. Knox et al. 2008

13/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-127 Appendices 1 Appendix 1: USDA Conservation Practice Standards (Practice Codes) 2
Referenced throughout the document 3
Appendix 2: Agricultural Existing Tools in Support of Section 502 Technical Guidance 4



## 5

. References 5 Aarnink, A.J.A., and M.W.A. Verstegen

. , M.W.A., ( 2007 ) . Nutrition, key factor to reduce 6 environmental load from pig production. Livestock Science 109 : , 194

– - 203. 7
Adler, P.R., and P.L. Sibrell

. , P.L., 2003. Sequestration of phosphorus by acid mine dra inage 8 floc. Journal of Environmental Quality 32 : , 1122

– - 1129. 9
Adrizal, A., P. H. Patterson, R.M. Hulet, R.M. Bates, C.A.B. Myers, G. Martin, R. L. Shockey, 10 M. Van der Grinten, D.A. Anderson, and J.R. Thompso n. et al. ( 2008

. ). " Vegetative 11 buffers for fan emissions from poultry farms: 2. am monia, dust and foliar nitrogen

. ." 12 Journal of Environmental Science and Health Part B- Pesticides Food Contaminants and 13 Agricultural Wastes 43(1): 96

– - 103. 14
Agouridis, C. T., D.R. Edwards, S. R. Workman, J. R. Bicudo, B.K. Koostra, E.S. Vanzant, and 15 J.L. 16

Taraba. 2005. “ Streambank erosion associated with grazing practice s in the humid region

. ,” 17 Transactions of the ASAE , Vol. 48(1): 181−190. 18
Agyin-Birikorang, S., G.A. O’Connor, L.W. O'Connor, G.A., Jacobs, K.C. L.W., Makris, and 19 S.R. K.C., Brinton

. , S.R., 2007. Long-term phosphorus immobilization by a dri nking water 20 treatment residual. Journal of Environmental Quality 36 : , 316

– - 323. 21
Ali, I., S. Barrington, R. S., Bonnell, J. R., Whalen, and J

. ., Martinez

. , J., 2007. Surface irrigation 22 of dairy farm effluent, Part II: System design and operation. Biosystems Engineering 96 : , 23 65

– - 77. 24
Allen, B.L., and A.R. Mallarino

. , A.R., 2008. Effect of liquid swine manure rate, incorpor ation, 25 and timing of rainfall on phosphorus loss with surf ace runoff. Journal of Environmental 26 Quality 37 : , 125

– - 137. 27
Allred, B. J., N.R. Fausey, B. N.R., Clevenger, G. B., Prill, G

. ., Labarge, S. G., Miller, P. S., 28 Chester, D. P., Riethman, and L. D., Brown

. , L. ( 2008

. ). " Water quality benefits of 29 constructed wetlands integrated Quality Benefits of Constructed Wetlands Integrated 30 within agricultural water recycling systems. Agricultural Water Recycling Systems. ." 31 Society of Wetland Scientists

. 32
Andraski, T.W., L.G. Bundy, and K.C. L.G., Kilian

. , K.C., 2003. Manure history and long-term 33 tillage effects on soil properties and phosphorus l osses in runoff. Journal of Environmental 34 Quality 32 : , 1782

– - 1789. 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-128 Appelboom, T. W.
, and J. L. Fouss

. ( 2006 )

. Methods for Removing Nitrate Nitrogen from 1 Agricultural Drainage Waters: A Review and Assessme nt

. 2
Arriaga, H., M. Pinto, S. M., Calsamiglia, and P. S., Merino

. , P., 2009. Nutritional and 3 management strategies on nitrogen and phosphorus us e efficiency of lactating dairy cattle 4 on commercial farms: An environmental perspective. Journal of Dairy Science 92 : , 204

– - 5 215. 6
Avalos, J. M. M., P. S. Fouz, E.V. Vaquez, A.P. Gonzalez, and I. Bertol. et al. ( 2007 ) . Crop 7 Residue Effects on Organic Carbon, Nitrogen, and Ph osphorus Concentrations and Loads 8 in Runoff Water. In Proceedings of the 10th International Symposium on Soil and Plant 9 Analysis , Budapest, Hungary HUNGARY , Taylor & Francis Inc. 10
Bakhsh, A., R.S. Kanwar, J.L. R.S., Baker, J. L., Sawyer, and A. J., Malarino

. , A., 2009. Annual 11 swine manure applications to soybean under corn-soy bean rotation. Trans. ASABE 52 : , 12 751

– - 757. 13
Bambo, S. K., J. Nowak, A.R. Blount, A.J. Long, and A. Osiecka. et al. ( 2009

. ). " Soil nitrate 14 leaching in silvopastures compared Nitrate Leaching in Silvopastures Compared with open 15 pasture and pine plantation. Open Pasture and Pine Plantation." Journal of Environmental 16 Quality 38(5): 1870

– - 1877. 17
Barbarika, A. Jr. 1987. Costs of soil conservation practices. In : Optimum Erosion Control at 18 Least Cost: Proceedings of the National Symposium o n Conservation Systems . American 19 Society of Agricultural Engineers St. Joseph, MI, p p. 187

– - 195. 20
Beck, M.A., L.W. Zelazny, W.L. Daniels, and G.L. Mu llins. 2004. Using the Mehlich-1 Extract 21 to Estimate Soil Phosphorus Saturation for Environm ental Risk Assessment. Soil Sci. Soc. 22 Am. J. 68:1762–1771. 23
Bedard-Haughn, A., K. W. Tate, and C. van Kessel. et al. ( 2005

. ). " Quantifying the impact of 24 regular cutting on vegetative buffer efficacy for n itrogen-15 sequestration

. ." Journal of 25 Environmental Quality 34(5): 1651

– - 1664. 26
Beegle, D. 2000. “ Integrating phosphorus and nitrogen management at t he farm level
, ,” 27 Agriculture and Phosphorus Management . In , IN: Agriculture and Phosphorus 28 Management: The Chesapeake Bay , A.N. Shapley, Ed., CRC Press, pp. 159

– - 168. 29
Bekele, A., A. M. S. McFarland, and A.J. Whisenant. et al. ( 2006

. ). " Impacts of a manure 30 composting program on stream water quality

. ." Transactions of the ASABE 49(2): 389

– - 31 400. 32
Bicudo, J. R. and S.M. Goyal. 2003. “ Pathogens and manure management systems: a review

. ,” 33 Environmental Technology 24(1): 115

– - 130. 34
Binstock, L. ( 2009

. ). “ Agricultural drainage water management steps into t he future

. ,” Land and 35 Water

March/April 2009: 52

– - 55 < , http://www.admcoalition.com/LandWater0309.pdf >. 36 Accessed , Retrieved February 21, 2010. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-129 Blackmer, A.M.
, and A.P. Mallarino. 1996. Cornstalk Testing to Evaluate Nitrogen Management 1 (PM-1584). Iowa State Univ ersity

. Extension. 2 <http://www.extension.iastate.edu/Publications/PM15 84.pdf>. Accessed February 3 Available on the Web at: http://www.extension.iasta te.edu/Publications/PM1584.pdf. 4 [URL verified 2/ 9 , 2010. 5
/10] 6
Blazier, M. A., L. A. Gaston, T.R. Clason, K.W. Farrish, B.P. Oswald, and H.A. Ev ans. et al. 7 ( 2008

. ). " Nutrient dynamics and tree growth of silvopastoral systems: Impact of poultry 8 litter

. ." Journal of Environmental Quality 37(4): 1546

– - 1558. 9
Blowes, D. W., W. D. Robertson, C.J. Ptacek, and C. Merkley. et al. ( 1994

. ). " Removal of 10 agricultural nitrate from tile-drainage effluent wa ter using in-line bioreactors

. ." Journal of 11 Contaminant Hydrology 15(3): 15. 12
Bolan, N. S., S. Laurenson, J. Luo, and J. Sukias. 2009. “ Integrated treatment of farm effluents in 13 New Zealand’s Zealand's dairy operations

. ,” Bioresource Technology 100(22): 5490

– - 5497. 14
Borin, M.
, and E. Bigon

. ( 2002

. ). " Abatement of NO3-N concentration in agricultural wa ters by 15 narrow buffer strips

. ." Environmental Pollution 117(1): 165

– - 168. 16
Borin, M., M. Vianello, F. Morari, and G. Zanin. et al. ( 2005

. ). " Effectiveness of buffer strips in 17 removing pollutants in runoff from a cultivated fie ld in North-East Italy

. ." Agriculture 18 Ecosystems & Environment 105(1

– - 2): 101

– - 114. 19
Brauer, D., G.E. Aiken, D.H. Pote, S.J. Livingston, L.D. Norton, T.R. Way, and J.H. Edwards. 20 2005. “ Amendment effects on soil test phosphorus

. ,” Journal of Environmental Quality 21 34(5): 1682

– - 1686. 22
Brodie, H. L., L. E. Carr, and P. Condon. et al. ( 2000

. ). " A comparison of static pile and turned 23 windrow methods for poultry litter compost producti on

. ." Compost Science & Utilization 24 8(3): 178

– - 189. 25
Brown, L. C., A. Ward, and N.R. Fausey

. ( 1997

. ). " Agricultural Water Table Management 26 Systems

. ." Ohio State University Fact Sheet AEX 321

– - 97: 8. 27
Burchell, M. R., R. W. Skaggs, G.M. Chescheir, J.W. Gilliam, and L.A. Arnold. et al. ( 2005

. ). 28

" Shallow subsurface drains to reduce nitrate losses from drained agricultural lands

. ." 48(3): 29 1079

– - 1089. 30
Burchell, M. R., R. W. Skaggs, C.R. Lee, S. Broome, G.M. Chescheir, and J. Osborne

. et al. 31 ( 2007

. ). " Substrate organic matter to improve nitrate removal in surface-flow constructed 32 wetlands

. ." Journal of Environmental Quality 36(1): 194

– - 207. 33
Butler, D. M., N. N. Ranells, D.H. Franklin, M.H. Poore, and J.T. Green. et al. ( 2007

. ). " Ground 34 cover impacts on nitrogen export from manured ripar ian pasture

. ." Journal of 35 Environmental Quality 36(1): 155

– - 162. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-130 Butler, D. M., N. N. Ranells, D.H. Franklin, M.H. Poore, and J.T. Green et al . 2008b. " Runoff 1 water quality from manured riparian grasslands with contrasting drainage and simulated 2 grazing pressure

. ." Agriculture Ecosystems & Environment 126(3

– - 4): 250

– - 260. 3
Butler, D.M., D.H. Franklin, M.L. D.H., Cabrera, A.S. M.L., Tasistro, K. A.S., Xia, and L.T. K., 4 West

. , L.T., 2008a. Evaluating aeration techniques for decreasi ng phosphorus export from 5 grasslands receiving manure. Journal of Environmental Quality 37 : , 1279

– - 1287. 6
Butler, J.S.
, and F. J. Coale. 2005. Phosphorus Leaching in Manure-Amend ed Atlantic Coastal 7 Plain Soils. Journal of Environmental Quality 34 : , 370–381. 8
Butt, A.J., and B.L. Brown

. , B.L., 2000. The cost of nutrient reduction: A case study of 9 Chesapeake Bay. Coastal Management 28 : , 175

– - 185. 10
Camacho, R. 1991. Financial Cost Effectiveness of Point and Nonpoint Source Nutrient 11 Reduction Technologies in the Chesapeake Bay Basin. Interstate Commission on the 12 Potomac River Basin, Rockville, MD Maryland . Unpublished draft. 13
Cantrell, K. B., J. P. Chastain, and K.P. Moore. et al. ( 2008

. ). " Geotextile filtration performance 14 for lagoon sludges and liquid animal manures dewate ring

. ." Transactions of the 15 ASABE

Asabe 51(3): 1067

– - 1076. 16
Carline, R. F.
, and M. C. Walsh

. ( 2007

. ). " Responses to riparian restoration in the Spring Cre ek 17 watershed, central Pennsylvania

. ." Restoration Ecology 15(4): 731

– - 742. 18
Cerosaletti, P.E., D.G. Fox, and L.E. D.G., Chase

. , L.E., 2004. Phosphorus reduction through 19 precision feeding of dairy cattle. Journal of Dairy Science 87 : , 2314

– - 2323. 20
Chastain, J. P., M. B. Vanotti, and M.M. Wingfield. et al. ( 2001

. ). " Effectiveness of liquid–solid 21 separation for treatment of flushed dairy manure: a case study

. ." Applied Engineering in 22 Agriculture 17(3): 343

– - 354 23
Chavan, P. V., K. E. Dennett, E.A. Marchand, and M.S. Gustin. et al. ( 2007

. ). " Evaluation of 24 small-scale constructed wetland for water quality a nd Hg transformation

. ." Journal of 25 Hazardous Materials 149(3): 543

– - 547. 26
Chavan, P. V., K. E. Dennett, and E.A. Marchand. et al. ( 2008

. ). " Behavior of pilot-scale 27 constructed wetlands in removing nutrients and sedi ments under varying environmental 28 conditions

. ." Water Air and Soil Pollution 192(1

– - 4): 239

– - 250. 29
Chen, D.W

. ., 2001. Environmental challenges of animal agricultu re and the role and task of 30 animal nutrition in environmental protection

— - Review. Asian-Australasian Journal of 31 Animal Sciences 14 : , 423-431. 32
Chen, Y., and R. Samson

. , R., 2002. Integration of liquid manure into conservatio n tillage corn 33 systems. Transactions of the ASAE Asae 45 : , 629

– - 638. 34
Cheng, M. 2001. Removal of chemical oxygen demand a nd phosphorus from livestock 35 wastewater by chemical treatment

. , Taiwanese Journal of Agricultural Chemistry and Foo d 36 Science 39(2): 129

– - 134. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-131 Chesapeake Bay Commission. ( 2004

. ). " Cost-Effective Strategies for the Bay

. 1 <http://www.chesbay.state.va.us/Publications/cost%2 0effective.pdf>. Accessed ." Retrieved 2 December 1, 2009 , from 3 http://www.chesbay.state.va.us/Publications/cost%20 effective.pdf

. 4
Chesapeake Bay Program Office. 2010. “ About the executive order . < .” 5 http://executiveorder.chesapeakebay.net/page/About- the-Executive-Order.aspx >. Accessed
, 6 Retrieved February 21, 2010. 7
Chien, S.H., L.I. Prochnow, and H. L.I., Cantarella

. , H., 2009. Recent developments of fertilizer 8 production and use to improve nutrient efficiency a nd minimize environmental impacts. 9 Advances in Agronomy, Vol 102. Elsevier Academic Pr ess Inc, San Diego, pp. 267

– - 322. 10
Choi, E., Y. Yu, M. Cui, Z. Yun, and K. Min. et al. ( 2008

. ). " Effect of biologically mediated pH 11 change on phosphorus removal in BNR system for pigg ery waste treatment

. ." Journal of 12 Environmental Science and Health Part a-Toxic/Hazar dous Substances & Environmental 13 Engineering 43(2): 154

– - 160. 14
Choi, I., C.L. Munster, D.M. C.L., Vietor, R.H. D.M., White, C.E. R.H
., Richards, G.A. C.E., 15 Stewart, and B. G.A., McDonald

. , B., 2003. Use of turfgrass sod to transport manure 16 phosphorus out of impaired watersheds. Total Maximu m Daily Load ( TMDL Tmdl ): 17 Environmental Regulations Ii, Proceedings, 518

– - 526. 18
Clausen, J. C., K. Guillard, C.M. Sigmund, and K.M. Dors. et al. ( 2000

. ). " Ecosystem 19 restoration - Water quality changes from riparian b uffer restoration in Connecticut

. ." 20 Journal of Environmental Quality 29(6): 1751

– - 1761. 21
Codling, E. E., R.L. Chaney, and C.L. Mulchi. 2000. Use of alum inum- and iron-rich residues to 22 immobilize phosphorus in poultry litter and litter- amended soils. Journal of Environmental 23 Quality 29(6): 1924

– - 1931. 24
Coelho, B.R.B., R .C. R oy, and A.J. R.C., Bruin

. , A.J., 2006. Nitrogen recovery and partitioning 25 with different rates and methods of sidedressed man ure. Soil Science Society of America 26 Journal 70 : , 464

– - 473. 27
Converse, J. C. and K. G. Karthikeyan ( 2004

. ). " Nutrient and solids separation of flushed dairy 28 manure by gravity settling

. ." Applied Engineering in Agriculture 20(4): 503

– - 507. 29
Cooke, R., J. Nehmelman, and P. Kalita. et al. ( 2002

. ). " Effect of Tile Depth on Nitrate 30 Transport from Tile Drainage Systems

. ." ASAE Meeting Paper No. 022017, St. Joseph, MI 31 2002 ASAE Annual International Meeting/CIGR XVth Wo rld Congress, Chicago: 16. 32
Cornell Cooperative Extension. 1997. 1997 Cornell Recommendations for Integrated Field C rop 33 Management. Resource Center, Cornell University, Ithaca, NY. 34
Costa, R. H. R., A.S.L. Bavaresco, W. Medri, and L.S. Philippi. 2000. “ Tertiary treatment of 35 piggery wastes in water hyacinth ponds

. ,” Water Science and Technology 42(10

– - 11): 211

– 36

- 214. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-132 Costa, R. D., C. R. G. Tavares, and E.S. Cossich. et al. ( 2007

. ). " Stabilization of swine wastes 1 by anaerobic digestion

. ." Environmental Technology 28: 1145

– - 1151. 2
Dabney, S. M., J. A. Delgado, and D.W. Reeves. et al. ( 2001 . Using winter cover crops to 3 improve soil and water quality )

. Communications in Soil Science and Plant Analysis 4 32(7&8 ): ), 1221–1250. 5 Dabney, S. M., Y. Yuan, and R.L. Bingner. et al. ( 2001

. ). " Evaluation of Best Management 6 Practices (BMPs) in the Mississippi Delta MSEA

. ." Abstracts of Papers American 7 Chemical Society 222(1

– - 2): AGRO117. 8
Das, K. C., M. Y. Minkara, N.D. Melear, and E.W. Tollner. et al. ( 2002

. ). " Effect of poultry 9 litter amendment on hatchery waste composting

. ." Journal of Applied Poultry Research 10 11(3): 282

– - 290. 11
Dauden, A., D. Quilez, and M.V. D., Vera

. , M.V., 2004. Pig slurry application and irrigation 12 effects on nitrate leaching in Mediterranean soil l ysimeters. Journal of Environmental 13 Quality 33 : , 2290

– - 2295. 14
Daverede, I.C., A.N. Kravchenko, R.G. A.N., Hoeft, E.D. R.G., Nafziger, E. D. G.
, Bullock, 15 J.J. D.G., Warren, L.C. J.J., Gonzini

. , L.C., 2004. Phosphorus runoff from incorporated and 16 surface-applied liquid swine manure and phosphorus fertilizer. Journal of Environmental 17 Quality 33 : , 1535

– - 1544. 18
Dayton, E. A.
, and N. T. Basta

. ( 2005

. ). " Use of drinking water residuals as a potential best 19 management practice to reduce phosphorus risk index scores. ." J. Environ. Qual. 34: 20 2112

– - 2117. 21
Dayton, E.A., N.T. Basta, C.A. N.T., Jakober, and J C .A

. ., Hattey

. , J.A., 2003. Using treatment 22 residuals to reduce phosphorus in agricultural runo ff. Journal American Water Works 23 Association 95 : , 151

– - 158. 24
Demirer, G. N. and S. Chen. 2005. “ Two-phase anaerobic digestion of unscreened dairy 25

manure

. ,” Process Biochemistry 40(11): 3542

– - 3549. 26
Deng, L.-w., P. Zheng, S. Li, X. Sun, and Y. Tang. et al. ( 2005

. ). " Performance improvement of 27 sequencing batch reactor (SBR) treating digested pi ggery wastewater by addition of raw 28 wastewater

. ." Huanjing Kexue 26(6): 105

– - 109. 29
Do, J. C., I. H. Choi, and K.H. Nahm. et al. ( 2005

. ). " Effects of chemically amended litter on 30 broiler performances, atmospheric ammonia concentra tion, and phosphorus solubility in 31 litter

. ." Poultry Science 84(5): 679

– - 686. 32
Dosskey, M. G., D. E. Eisenhauer, and M.J. Helmers. et al. ( 2005

. ). " Establishing conservation 33 buffers using precision information

. ." Journal of Soil and Water Conservation 60(6): 349

– - 34 354. 35
Dosskey, M. G., K. D. Hoagland, and J.R. Brandle. et al. ( 2007

. ). " Change in filter strip 36 performance over ten years

. ." Journal of Soil and Water Conservation 62(1): 21

– - 32. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-133 Dosskey, M. G., M. J. Helmers, and D.E. Eisenhauer. et al. ( 2006

. ). " An approach for using soil 1 surveys to guide the placement of water quality buf fers

. ." Journal of Soil and Water 2 Conservation 61(6): 344

– - 354. 3
Dosskey, M. G., M. J. Helmers, and D.E. Eisenhauer. et al. ( 2008

. ). " A design aid for 4 determining width of filter strips

. ." Journal of Soil and Water Conservation 63(4): 232

– - 5 241. 6
Dou, Z., G. Y. Zhang, W.L. Stout, and J.D. Toth. et al. ( 2003

. ). " Efficacy of alum and coal 7 combustion by-products in stabilizing manure phosph orus

. ." Journal of Environmental 8 Quality 32(4): 1490

– - 1497. 9
Drury, C. F., C. S. Tan, J.D. Gaynor, T.O. Oloya, and T.W. Welacky. et al. ( 1996

. ). " Influence 10 of Controlled Drainage-Subirrigation on Surface and Tile Drainage Nitrate Loss

. ." J 11 Environ Qual 25: 8. 12
Drury, C. F., C. S. Tan, W.D. Reynolds, T.W. Welacky, T.O. Oloya, and J.D. G aynor. et al. 13 ( 2009

. ). " Managing Tile Drainage, Subirrigation, and Nitrogen Fertilization to Enhance 14 Crop Yields and Reduce Nitrate Loss

. ." Journal of Environmental Quality 38(3): 1193

– - 15 1204. 16
Dunne, E. J., K. A. McKee, M.W. Clark, S. Grunwald, and K.R. Reddy. et al. ( 2006 )

. 17 Phosphorus in agricultural ditch soil and potential implications for water quality

. 18 Conference on Managing Agricultural Drainage Ditche s for Water Quality Protection, 19 College Pk, MD, Soil Water Conservation Soc. 20
Dunne, E. J., N. Culleton, G. O’Donovan O'Donovan , and R. Harrington. 2004. “ Constructed 21 wetlands to retain contaminants and nutrients, spec ifically phosphorus from farmyard dirty 22 water in Southeast Ireland
, ,” International Symposium on Nutrient Management in 23 Agricultural Watersheds - A Wetlands Solution, Wexf ord, Ireland, Wageningen Academic 24 Publishers, pp. 144

– - 156. 25
Dunne, E. J., N. Culleton, G. O’Donovan, R. Harrington, and A.E. Olsen. et al. ( 2005

. ). " An 26 integrated constructed wetland to treat contaminant s and nutrients from dairy farmyard 27 dirty water

. ." Ecological Engineering 24(3): 221

– - 234. 28
Ebeling, A.M., L.G. Bundy, J.M. L.G., Powell, and T.W. J.M., Andraski

. , T.W., 2002. Dairy diet 29 phosphorus effects on phosphorus losses in runoff f rom land-applied manure. Soil Science 30 Society of America Journal 66 : , 284

– - 291. 31
Edgerton, B. D., D. McNevin, C.H. Wong, P. Menoud, J.P. Barford, and C.A. Mitche ll. et al. 32 ( 2000

. ). " Strategies for dealing with piggery effluent in Aus tralia: the sequencing batch 33 reactor as a solution

. . " Water Science and Technology 41(1): 123

– - 126. 34
El Hafiane, F., A. Rami, and B. El Hamouri. 2003. “ Mechanisms of nitrogen and phosphorus 35 removal in a high rate algal pond

. ,” Revue des Sciences de l’Eau l'Eau 16(2): 157

– - 172. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-134 Elliott, H.A., G.A. O’Connor, P. O'Connor, G.A., Lu, and S. P., Brinton

. , S., 2002. Influence of 1 water treatment residuals on phosphorus solubility and leaching. Journal of Environmental 2 Quality 31 : , 1362

– - 1369. 3
Emiola, A., O. Akinremi, B. Slominski, and C.M. Nyachoti. et al. ( 2009

. ). " Nutrient utilization 4 and manure P excretion in growing pigs fed corn-bar ley-soybean based diets supplemented 5 with microbial phytase

. ." Animal Science Journal 80(1): 19

– - 26. 6
Entry, J. A. and R. E. Sojka

. ( 2000

. ). " The efficacy of polyacrylamide and related compound s 7 to remove microorganisms and nutrients from animal wastewater

. ." Journal of 8 Environmental Quality 29(6): 1905

– - 1914. 9
Evans, R
., . and W. Skaggs

. ( 1996

. ). " Operating controlled drainage and subirrigation 10 systems

. ." North Carolina Cooperative Extension Service Publication Number: AG 356 8. 11
Evans, R., J. W. Gilliam, and W. Skaggs. et al. ( 1996

. ). " Controlled drainage management 12 guidelines for improving drainage water quality

. ." North Carolina Cooperative Extension 13 Service Publication Number: AG 443: 18. 14
Evans, R., W. Skaggs, and R.E. Sneed. et al. ( 1996

. ). " Economics of controlled drainage and 15 subirrigation systems

. ." North Carolina Cooperative Extension Service Publi cation 16 Number: AG 397 16. 17
Fajardo, J. J., J. W. Bauder, and S.D. Cash. et al. ( 2001

. ). " Managing nitrate and bacteria in 18 runoff from livestock confinement areas with vegeta tive filter strips

. ." Journal of Soil and 19 Water Conservation 56(3): 185

– - 191. 20
Fausey, N. ( 2005

. ). " Drainage Management for Humid Regions

. ." International Agricultural 21 Engineering Journal 14(4): 6. 22
Federal Leadership Committee for the Chesapeake Bay

. ( 2009

. ). “ Draft strategy for protecting 23 and restoring the Chesapeake Bay . < ”, 24 http://executiveorder.chesapeakebay.net/category/Re ports-Documents.aspx >. Accessed
, 25 retrieved February 21, 2010. 26
Fisher, J. and M. C. Acreman

. ( 2004

. ). " Wetland nutrient removal: a review of the evidence

. ." 27 Hydrology and Earth System Sciences 8(4): 673

– - 685. 28
Flanagan, D. C., L. D. Norton, J.R. Peterson, and K. Chaudhari. et al. ( 2003

. ). " Using 29 polyacrylamide to control erosion on agricultural a nd disturbed soils in rainfed areas

. ." 30 Journal of Soil and Water Conservation 58(5): 301

– - 311. 31
Frankenberger, J., E. Kladivko, G. Sands, D. Jaynes , N. Fausey, M. Helmers, R. Cooke, J. 32 Strock, K. N. Nelson , and L. Brown

. ( 2006

. ). " Questions and Answers About Drainage 33 Water Management for the Midwest

. ." Purdue University Water Quality Program, Purdue 34 Extension Knowledge to Go WQ

– - 44: 8. 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-135 Franklin, D. H., M. L. Cabrera, H.L. Byers, M.K. Matthews, J.G. Andrae, D.E. Radcli ffe, M.A. 1 McCann, H.A. Kuykendall, C.S. Hoveland, and V.H. Ca lvert. et al. ( 2009

. ). " Impact of 2 water troughs on cattle use of riparian zones in th e Georgia Piedmont in the United 3 States

. ." Journal of Animal Science 87(6): 2151

– - 2159. 4
Franklin, D.H., M.L. Cabrera, and V.H. M.L., Calvert

. , V.H., 2006. Fertilizer source and soil 5 aeration effects on runoff volume and quality. Soil Science Society of America Journal 70 : , 6 84

– - 89. 7
Franklin, D.H., M.L. Cabrera, M. L. T.
, West, V.H. L.T., Calvert, and J.A. V.H., Rema

. , J.A., 8 2007. Aerating grasslands: Effects on runoff and ph osphorus losses from applied broiler 9 litter. Journal of Environmental Quality 36 : , 208

– - 215. 10
Franzluebbers, A. J. ( 2005 )

. Integrated crop-livestock systems in the southeaste rn USA

. 11 Symposium on Integrated Crop-Livestock Systems for Profit and Sustainability, Salt Lake 12 City, UT, Amer Soc Agronomy. 13
Franzluebbers, A. J. and J. A. Stuedemann

. ( 2008

. ). " Soil physical responses to cattle grazing 14 cover crops under conventional and no tillage in th e Southern Piedmont USA

. ." Soil & 15 Tillage Research 100(1

– - 2): 141

– - 153. 16
Garcia, M. C., A. A. Szogi, M.B. Vanotti, J.P. Chastain, and P.D. Millner. et al. ( 2009

. ). 17

" Enhanced solid-liquid separation of dairy manure wi th natural flocculants

. ." Bioresource 18 Technology 100(22): 5417

– - 5423. 19
Garrett, H. E., M. S. Kerley, K.P. Ladyman, W.D. Walter, L.D. Godsey, J.W. Van Sa mbeek, and 20 D.K. Brauer. et al. ( 2004

. ). " Hardwood silvopasture management in North America

. ." 21 Agroforestry Systems 61

– - 2(1): 21

– - 33. 22
Garrison, A. V.
, and T. L. Richard

. ( 2005

. ). " Methane and manure: Feasibility analysis of price 23 and policy alternatives

. ." Transactions of the ASAE Asae 48(3): 1287

– - 1294. 24
Gaynor, J. D.
, and W. I. Findlay

. ( 1995

. ). " Soil and phosphorus loss from conservation and 25 conventional tillage in corn production

. ." Journal of Environmental Quality 24(4): 734

– - 26 741. 27
Geohring, L.D., O.V. McHugh, M.T. O.V., Walter, M. T. S.
, Steenhuis, M T .S

. ., Akhtar, and M.S., 28 Walter, M.F . Walter.
., 2001. Phosphorus transport into subsurface drains by macropores 29 after manure applications: implications for best ma nure management practices. Soil Science 30 166 : , 896

– - 910. 31
Ghadiri, H., C. W. Rose, and W.L. Hogarth. et al. ( 2001

. ). " The influence of grass and porous 32 barrier strips on runoff hydrology and sediment tra nsport

. ." Transactions of the ASAE Asae 33 44(2): 259

– - 268. 34
Gharabaghi, B., R. P. Rudra, H.R. Whiteley, and W.T. Dickinson. et al. ( 2001 ) . Sediment35 Removal Efficiency of Vegetative Filter Strips. 2001 ASAE Annual International Meeting

. 36 Sacramento, California, USA. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-136 Ghebremichael, L.T., P.E. Cerosaletti, T.L. P.E., Veith, C.A. T.L., Rotz, J.M. C.A., Hamlett, and 1 W. J. M., Gburek

. , W.J., 2007. Economic and phosphorus-related effects of p recision 2 feeding and forage management at a farm scale. Journal of Dairy Science 90 : , 3700

– - 3715. 3
Giasson, E., R.B. Bryant, and N.L. R.B., Bills

. , N.L., 2003. Optimization of phosphorus index 4 and costs of manure management on a New York dairy farm. Agronomy Journal 95 : , 987

– - 5 993. 6
Gibbs, P. A., R. J. Parkinson, T.H. Misselbrook, and S. Burchett. et al. ( 2002

. ). " Environmental 7 impacts of cattle manure composting

. ." Microbiology of Composting : 445

– - 456. 8
Gilley, J. E., B. Eghball, L.A. Kramer, and T.B. Moorman. et al. ( 2000

. ). " Narrow grass hedge 9 effects on runoff and soil loss

. ." Journal of Soil and Water Conservation 55(2): 190

– - 196. 10
Gilley, J. E., E. D. Berry, R.A. Eigenberg, D.B. Marx, and B.L. Woodbury. et al. ( 2008

. ). 11

" Spatial variations in nutrient and microbial transp ort from feedlot surfaces

. ." Transactions 12 of the ASABE Asabe 51(2): 675

– - 684. 13
Gilliam, J. W., R. W. Skaggs, and S.B. Weed. et al. ( 1979

. ). " Drainage Control to Diminish 14 Nitrate Loss from Agricultural Fields

. ." J Environ Qual 8: 6. 15
Giroux, M., and R. Royer

. ., R., 2007. Long term effects of phosphate applications on yields, 16 evolution of P soil test, saturation, and solubilit y in two very rich soils.

. Agrosolutions 18 : , 17 17

– - 24. 18
Gold, M.V
., . and R.S. Thompson

. , 2009. “ Alternative crops & enterprises for small farm 19 diversification

. , USDA-ARS, National Agricultural Library < , 20 http://www.nal.usda.gov/afsic/pubs/altlist.shtml >. and 21
< http://www.nal.usda.gov/afsic/pubs/altlist.pdf >. Accessed , Retrieved February 21, 2010. 22
Gonzalez, C., J. Marciniak, S. Villaverde, C. Leon, P.A. Garcia, and R. Munoz. 2008. “ Efficient 23 nutrient removal from swine manure in a tubular bio film photo-bioreactor using algae24 bacteria consortia

. ,” Water Science and Technology 58(1): 95

– - 102. 25
Graham, H., P.H. Simmins, and J. P.H., Sands

. , J., 2003. Reducing environmental pollution 26 using animal feed enzymes. Communications in Agricultural and Applied Biologic al 27 Sciences 68, 285

– - 289. 28
Grandhi, R.R

. ., 2001. Effect of supplemental phytase and ideal die tary amino acid ratios in 29 covered and hulless-barley-based diets on pig perfo rmance and excretion of phosphorus 30 and nitrogen in manure. Canadian Journal of Animal Science 81, 115

– - 124. 31
Grigg, B. C., L. M. Southwick, J.L. Fouss, and T.S. Kornecki. et al. ( 2003

. ). " Drainage system 32 impacts on surface runoff, nitrate loss, and crop y ield on a southern alluvial soil

. ." 33 Transactions of the ASAE 46(6): 1531

– - 1537. 34
Gu, B. H. ( 2008

. ). " Phosphorus removal in small constructed wetlands do minated by submersed 35 aquatic vegetation in South Florida, USA

. ." Journal of Plant Ecology- UK Uk 1(1): 67

– - 74. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-137 Gu, B. H. and T. Dreschel

. ( 2008). " Effects of plant community and phosphorus loading r ate on 1 constructed wetland performance in Florida, USA

. ." Wetlands 28(1): 81

– - 91. 2
Gungor-Demirci, G.
, and G. N. Demirer

. ( 2004

. ). " Effect of initial COD concentration, nutrient 3 addition, temperature and microbial acclimation on anaerobic treatability of broiler and 4 cattle manure

. ." Bioresource Technology 93(2): 109

– - 117. 5
Guo, M.X., N. Tongtavee, and M. N., Labreveux

. , M., 2009. Nutrient dynamics of field6 weathered Delmarva poultry litter: implications for land application. Biology and Fertility 7 of Soils 45 : , 829

– - 838. 8
Harmel, D., S. Potter, P. Casebolt, K. Reckhow, C. Green, and R. Haney. et al. ( 2006

. ). 9

" Compilation of measured nutrient load data for agri cultural land uses in the United 10 States

. ." Journal of the American Water Resources Association 42(5): 1163

– - 1178. 11
Harmel, D., S. Qian, K. Reckhow, and P. Casebolt. et al. ( 2008

. ). " The MANAGE Database: 12 Nutrient Load and Site Characteristic Updates and R unoff Concentration Data

. ." Journal of 13 Environmental Quality 37(6): 2403

– - 2406. 14
Harrington, R.
, and R. McInnes

. ( 2009

. ). " Integrated Constructed Wetlands (ICW) for livestock 15 wastewater management

. ." Bioresource Technology 100(22): 5498

– - 5505. 16
Hartwig, N.L., and H.U. Ammon. 2002. Cover crops an d living mulches. Weed Sci. 50:688

– - 17 699. 18
Haustein, G.K., T.C. Daniel, D.M. T.C., Miller, P.A. D.M., Moore, and R.W. P.A., McNew

. , 19 R.W., 2000. Aluminum-containing residuals influence high -phosphorus soils and runoff 20 water quality. Journal of Environmental Quality 29 : , 1954

– - 1959. 21
He, B. J., Y. Zhang, T.L. Funk, G.L. Riskowski, and Y. Yin. et al. ( 2000

. ). " Thermochemical 22 conversion of swine manure: An alternative process for waste treatment and renewable 23 energy production

. ." Transactions of the ASAE Asae 43(6): 1827

– - 1833. 24
Healy, M. G., M. Rodgers, and J. Mulqueen. et al. ( 2004

. ). " Recirculating sand filters for 25 treatment of synthetic dairy parlor washings

. ." Journal of Environmental Quality 33(2): 26 713

– - 718. 27
Healy, M. G., M. Rodgers, and J. Mulqueen. et al. ( 2007

. ). " Performance of a stratified sand 28 filter in removal of chemical oxygen demand, total suspended solids and ammonia nitrogen 29 from high-strength wastewaters

. ." Journal of Environmental Management 83(4): 409

– - 415. 30
Hirschi, M., R. Frazee, G. Czapar, and D. Peterson. 1997. 60 Ways Farmers Can Protect Surface 31 Water , North Central Regional Extension Publication 589, Information Technology and 32 Communication Services, College of Agricultural, Co nsumer and Environmental Sciences, 33 University of Illinois, Urbana- Champaign, IL, 317 pp. 34
Hirschi, M.C., F.W. Simmons, D. Peterson, E. Giles. 1993. 50 Ways Farmers Can Protect their 35 Groundwater. Cooperative Extension Service. University of Illino is, Urbana, Illinois. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-138 Hoffmann, C. C., C. Kjaergaard, J. Uusi-Kamppa, H.C.B. Hansen, and B. Kronvang. et al. ( 2009

. 1 ). " Phosphorus Retention in Riparian Buffers: Review of Their Efficiency

. ." Journal of 2 Environmental Quality 38(5): 1942

– - 1955. 3
Hook, P. B. ( 2003

. ). " Sediment retention in rangeland riparian buffers

. ." Journal of 4 Environmental Quality 32(3): 1130

– - 1137. 5
Hoyt, G. D. ( 2005 ) Winter Annual Cover Crops. SoilFacts . North Carolina State University. 6 <http://www.soil.ncsu.edu/publications/Soilfacts/AG W-439-58/AGW_439_58.pdf>. 7 http://www.soil.ncsu.edu/publications/Soilfacts/AGW

- 439

- 58/AGW_439_58.pdf 8
Hubbard, R. K., G. L. Newton, and J.M. Ruter. et al. ( 2007

. ). " A farm-scale test of nitrogen 9 assimilation by vegetated buffer systems receiving swine lagoon effluent by overland 10 flow

. ." Transactions of the ASABE Asabe 50(1): 53

– - 64. 11
Hunt, P.G. and M.E. Poach. 2002. “ State of the art for animal wastewater treatment in 12 constructed wetlands

. ,” Water Science and Technology 44(11

– - 12): 19

– - 25. 13
Hunt, P. G., K.C. Stone, T.A. Matheny, M.E. Poach, M.B. Vano tti, and T.F. Ducey. 2009. 14

“ Denitrification of nitrified and non-nitrified swin e lagoon wastewater in the suspended 15 sludge layer of treatment wetlands

. ,” Ecological Engineering 35(10): 1514

– - 1522. 16
Hyde, J.E., and T.F. Morris

. , T.F., 2000. Phosphorus availability in soils amended wit h 17 dewatered water treatment residual and metal concen trations with time in residual. Journal 18 of Environmental Quality 29 : , 1896

– - 1904. 19
James, E., P. Kleinman, T. Veith, R. Stedman, and A. Sharpley. et al. ( 2007

. ). " Phosphorus 20 contributions from pastured dairy cattle to streams of the Cannonsville Watershed, New 21 York

. ." Journal of Soil and Water Conservation 62(1): 40

– - 47. 22
Jaynes, D. B., T. C. Kaspar, T.B. Moorman, and T.B. Parkin. et al. ( 2004 ) . Potential methods for 23 reducing nitrate losses in artificially drained fie ld. Drainage VIII Proceedings of the Eighth 24 International Symposium , Sacramento, CA. 25
Jin, C. X ., and . and M. J. M. J.M. Romkens

. ( 2001

. ). " Experimental studies of factors in 26 determining sediment trapping in vegetative filter strips

. ." Transactions of the ASAE Asae 27 44(2): 277

– - 288. 28
Jin, C. X., S. M. Dabney, and M.J.M. Romkens. et al. ( 2002

. ). " Trapped mulch increases 29 sediment removal by vegetative filter strips: A flu me study

. ." Transactions of the 30 ASAE

Asae 45(4): 929

– - 939. 31
Johnson, J.T., R.D. Lee, and R.L. Stewart. 1997. Pastures in Georgia . Bulletin 573, Cooperative 32 Extension Service, College of Agricultural & Enviro nmental Sciences, University of 33 Georgia, Athens, GA, 31 pp. 34
Jones, R. M. and S. P. Brown

. ( 2000

. ). " Chemical and settling treatment of dairy wastewater for 35 solids separation and phosphorus removal

. ." Animal, Agricultural and Food Processing 36 Wastes : 132

– - 141. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-139 Jordan, T. E., D. F. Whigham, K.H. Hofmockel, and M.A. Pittek. et al. ( 2003

. ). " Nutrient and 1 sediment removal by a restored wetland receiving ag ricultural runoff

. ." Journal of 2 Environmental Quality 32(4): 1534

– - 1547. 3
Kaiser, D.E., Mallarino, A.P., Haq, M.U., Allen, B. L

. ., 2009. Runoff Phosphorus Loss 4 Immediately after Poultry Manure Application as Inf luenced by the Application Rate and 5 Tillage. Journal of Environmental Quality 38 : , 299

– - 308 6
Kalita, P. K. and R. S. Kanwar

. ( 1993

. ). " Effect of Water-table Management Practices on the 7 Transport of Nitrate-N to Shallow Groundwater

. ." 36(2): 413

– - 422. 8
Kalita, P. K., R. A. C. Cooke, S.M. Anderson, M.C. Hirschi, and J.K. Mitchell. et al. ( 2007

. ). 9

" Subsurface Drainage and Water Quality: The Illinois Experience

. ." 50(5): 1651

– - 1656. 10
Kallenbach, R. L., M. S. Kerley, and G.J. Bishop-Hurley. et al. ( 2006

. ). " Cumulative forage 11 production, forage quality and livestock performanc e from an annual ryegrass and cereal 12 rye mixture in a pine walnut silvopasture

. ." Agroforestry Systems 66(1): 43

– - 53. 13
Kemper, N. P. and H. L. Goodwin

. ( 2009

. ). " Feasibility and production costs of composting 14 breeder and pullet litter with eggshell waste

. ." Journal of Applied Poultry Research 18(2): 15 172

– - 184. 16
Khose, K.K., Ranade, A.S., Kadam, M.M., Jagatap, S. K., Gole, M.A

. ., 2003. Effect of phytase 17 supplementation on performance of broilers fed low phosphorus diet. Indian Journal of 18 Poultry Science 38 : , 288

– - 290. 19
Kim, Y.-J., L. D. Geohring, and T.S. Steenhuis. et al. ( 2003 ) . Phosphorus Removal in Vegetative 20 Filter Strips Receiving Milkhouse Wastewater and Ba rnyard Runoff. 2003 ASAE 21 International Meeting . Las Vegas, NV. 22
King, K.W., and H.A. Torbert

. , H.A., 2007. Nitrate and ammonium losses from surface-app lied 23 organic and inorganic fertilizers. Journal of Agricultural Science 145 : , 385

– - 393. 24
Kladivko, E. J., J. R. Frankenberger, D.B. Jaynes, D.W. Meek, B.J. Jenkinson, and N.R. Fa usey. 25 et al. ( 2004

. ). " Nitrate leaching to subsurface drains as affected b y drain spacing and 26 changes in crop production system

. ." J. Environ. Qual. 33: 11. 27
Kleinman, P.J.A., A.N. Sharpley, L.S. A.N., Saporito, A.R. L.S., Buda, and A. R. B.
, Bryant

. , 28 R.B., 2009. Application of manure to no-till soils: phosp horus losses by sub-surface and 29 surface pathways. Nutrient Cycling in Agroecosystems 84 : , 215

– - 227. 30
Klik, A., A. S. Zartl, and J. Rosner. et al. ( 2001 )

. Tillage effects on soil erosion, nutrient, and 31 pesticide transport . International Symposium on Soil Erosion Research for the 21st 32 Century, Honolulu, HI Hi , Amer Soc Agr Engineers. 33
Knowlton, K.F., J.S. Radcliffe, C.L. J.S., Novak, and D.A. C.L., Emmerson

. , D.A., 2004. Animal 34 management to reduce phosphorus losses to the envir onment. J

. Anim

. Sci

. 82 E-Suppl, 35 E173

– - 195. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-140 Knox, A. K., R. A. Dahgren, K.W. Tate, and E.R. Atwill. et al. ( 2008

. ). " Efficacy of natural 1 wetlands to retain nutrient, sediment and microbial pollutants

. ." Journal of Environmental 2 Quality 37(5): 1837

– - 1846. 3
Koelsch, R. K., J. C. Lorimor, and K. R. Mankin. 2006. Vegetative treatment systems for 4 management of open lot runoff: a review of the lite rature. Applied Engineering in 5 Agriculture 22(1): 141

– - 153. 6
Koenig, R. T., M.D. Palmer, F.D. Miner, B.E. Miller, and J.D. Harrison. 2005. “ Chemical 7 amendments and process controls to reduce ammonia v olatilization during in-house 8 composting

. ,” Compost Science & Utilization 13(2): 141

– - 149. 9
Kovacic, D. A., M. B. David, L.E. Gentry, K.M. Starks, and R.A. Cooke. et al. ( 2000

. ). 10

" Effectiveness of constructed wetlands in reducing n itrogen and phosphorus export from 11 agricultural tile drainage

. ." Journal of Environmental Quality 29(4): 1262

– - 1274. 12
Kovacic, D. A., R. M. Twait, M.P. Wallace, and J.M. Bowling. et al. ( 2005 )

. Use of created 13 wetlands to improve water quality in the Midwest - Lake Bloomington case study . 5th 14 Annual Conference of the American-Ecological-Engine ering-Society, Columbus, OH, 15 Elsevier Science Bv. 16
Kovzelove, C*., T. Simpson, and R. Korcak. ( 2010 ) “ Quantification and 17 Implications of Surplus Phosphorus and Manure in Ma jor Animal Production 18 Regions of Maryland, Pennsylvania, and Virginia

. . ” Water Stewardship, Inc.
, Annapolis, 19 MD. 20 * On detail from U.S. EPA 21 <http://www.corporatewaterstewardship.org/downloads /P_PAPER_FINAL_2-9-10.pdf>. 22
( http://www.corporatewaterstewardship.org/downloads/ P_PAPER_FIN AL_2

- 9

- 10.pdf ) 23
Kroger, R., M. M. Holland, M.T. Moore, and C.M. Cooper. et al. ( 2007

. ). " Hydrological 24 variability and agricultural drainage ditch inorgan ic nitrogen reduction capacity

. ." Journal 25 of Environmental Quality 36(6): 1646

– - 1652. 26
Ladha, J.K., H. Pathak, T.J. H., Krupnik, T. J

. ., Six, J. and C. van Kessel , C . 2005. Efficiency of 27 fertiliser nitrogen in cereal production: retrospec ts and prospects. Advances in Agronomy 28 87:85

– - 156. 29
Lansing, S., R. B. Botero, and J.F. Martin. et al. ( 2008a

. ). " Waste treatment and biogas quality 30 in small-scale agricultural digesters

. ." Bioresource Technology 99(13): 5881

– - 5890. 31
Lansing, S., J. Viquez, H. Martinez, R. Botero, and J. Martin. et al. ( 2008b

. ). " Quantifying 32 electricity generation and waste transformations in a low-cost, plug-flow anaerobic 33 digestion system

. ." Ecological Engineering 34(4): 332

– - 348. 34
Larney, F. J. and X. Y. Hao

. ( 2007

. ). " A review of composting as a management alternative for 35 beef cattle feedlot manure in southern Alberta, Can ada

. ." Bioresource Technology 98: 36 3221

– - 3227. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-141 Layden, N. M., H. G. Kelly, D.S. Mavinic, R. Moles, and J. Bartlett. et al. ( 2007

. ). " Autothermal 1 thermophilic aerobic digestion (ATAD) - Part II: Re view of research and full-scale 2 operating experiences

. ." Journal of Environmental Engineering and Science 6(6): 679

– - 3 690. 4
Lee, B. H. and W. C. Song

. ( 2006

. ). " High concentration of ozone application by the DAF 5 (Dissolved Air Flotation) system to treat livestock wastewater

. ." Water Pollution VIII: 6 Modelling, Monitoring and Management 95: 561

– - 569. 7
Lee, C. Y., C. C. Lee, F.Y. Lee, S.K. Tseng, and C.J. Liao. et al. ( 2004

. ). " Performance of 8 subsurface flow constructed wetland taking pretreat ed swine effluent under heavy loads

. ." 9 Bioresource Technology 92(2): 173

– - 179. 10
Lee, K. H., T. M. Isenhart, R.C. Schultz, and S.K. Mickelson. et al. ( 2000

. ). " Multispecies 11 riparian buffers trap sediment and nutrients during rainfall simulations

. ." Journal of 12 Environmental Quality 29(4): 1200

– - 1205. 13
Lee, K. H., T. M. Isenhart, and R.C. Schultz. et al . ( 2003

. ). " Sediment and nutrient removal in 14 an established multi-species riparian buffer

. ." Journal of Soil and Water Conservation 15 58(1): 1

– - 8. 16
Lefcourt, A. M. and J. J. Meisinger

. ( 2001

. ). " Effect of adding alum or zeolite to dairy slurry on 17 ammonia volatilization and chemical composition

. ." Journal of Dairy Science 84(8): 1814

– 18

- 1821. 19
Lewis, T.W., and J.C. Makarewicz

. , J.C., 2009. Winter application of manure on an agricultu ral 20 watershed and its impact on downstream nutrient flu xes. Journal of Great Lakes Research 21 35 : , 43

– - 49. 22
Leytem, A.B., Plumstead, P.W., Maguire, R.O., Kwany uen, P., Burton, J.W., Brake, J

. ., 2008. 23 Interaction of calcium and phytate in broiler diets . 2. Effects on total and soluble 24 phosphorus excretion. Poult. Sci. 87, 459

– - 467. 25
Lin, C. H., R. N. Lerch, H.E. Garrett, D. Jordan, and M.F. George. et al. ( 2007

. ). " Ability of 26 forage grasses exposed to atrazine and isoxaflutole to reduce nutrient levels in soils and 27 shallow groundwater

. ." Communications in Soil Science and Plant Analysis 38(9

– - 10): 28 1119

– - 1136. 29
Line, D. E. ( 2003

. ). " Changes in a stream’s physical and biological condi tions following 30 livestock exclusion

. ." Transactions of the ASAE 46(2): 287

– - 293. 31
Line, D. E., W. A. Harman, G.D. Jennings, E.J. Thompson, and D.L. Osmond. et al . ( 2000

. ). 32

" Nonpoint-source pollutant load reductions associate d with livestock exclusion

. ." Journal 33 of Environmental Quality 29(6): 1882

– - 1890. 34
Liu, X. M., X. Y. Mang, and M.H. Zhang. et al. ( 2008

. ). " Major factors influencing the efficacy 35 of vegetated buffers on sediment trapping: A review and analysis

. ." Journal of 36 Environmental Quality 37(5): 1667

– - 1674. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-142 Loeffler, P. A.
, and T. A. van Kempen

. ( 2003

. ). " Evaluation of ammonia rocovery waste 1 treatment for swine urine

. ." Animal, Agricultural and Food Processing Wastes Ix, 2 Proceedings : 568

– - 575. 3
Loria, E.R., and J.E. Sawyer

. , J.E., 2005. Extractable soil phosphorus and inorganic ni trogen 4 following application of raw and anaerobically dige sted swine manure. Agronomy Journal 5 97 : , 879

– - 885. 6
Loria, E.R., J.E. Sawyer, D.W. J.E., Barker, J.P. D.W., Lundvall, and J. C. P., Lorimor

. , J.C., 7 2007. Use of anaerobically digested swine manure as a nitrogen source in corn production. 8 Agronomy Journal 99 : , 1119

– - 1129. 9
Lu, J. B., Z. H. Fu, and Z.Z. Yin. et al. ( 2008

. ). " Performance of a water hyacinth (Eichhornia 10 crassipes) system in the treatment of wastewater fr om a duck farm and the effects of using 11 water hyacinth as duck feed

. ." Journal of Environmental Sciences-China 20(5): 513

– - 519. 12
Lu, L., S. A. Zhang, H. Li, Z.D. Wang, J.J. Li, Z.J. Zhang, and J. Zhu. et al. ( 2009

. ). " A 13 reformed SBR technology integrated with two-step fe eding and low-intensity aeration for 14 swine wastewater treatment

. ." Environmental Technology 30(3): 251

– - 260. 15
Lue, L., Z. Wang, S. Zhang, and Z. Zhang. 2008. “ Denitrifying phosphorus-accumulating SBR 16 combined with low-intensity aeration technology for piggery wastewater treatment
, ,” 17 Huanjing Kexue 29(7): 1884

– - 1889. 18
Lyons, J., B. M. Weigel, L.K. Paine, and D.J. Undersander. et al. ( 2000

. ). " Influence of 19 intensive rotational grazing on bank erosion, fish habitat quality, and fish communities in 20 southwestern Wisconsin trout streams

. ." Journal of Soil and Water Conservation 55(3): 21 271

– - 276. 22
Magner, J. A., B. Vondracek, and K.N. Brooks. et al. ( 2008

. ). " Grazed riparian management and 23 stream channel response in southeastern minnesota ( USA) streams

. ." Environmental 24 Management

42(3): 377

– - 390. 25
Maguire, R.O., D.A. Crouse, and S.C. D.A., Hodges

. , S.C., 2007. Diet modification to reduce 26 phosphorus surpluses: A mass balance approach. Journal of Environmental Quality 36 : , 27 1235

– - 1240. 28
Maguire, R.O., Z. Dou, J.T. Z., Sims, J. T., Brake, and B.C. J., Joern

. , B.C., 2005. Dietary 29 strategies for reduced phosphorus excretion and imp roved water quality. Journal of 30 Environmental Quality 34 : , 2093

– - 2103. 31
Maguire, R.O., G.L. Mullins, and M. G.L., Brosius

. , M., 2008. Evaluating long-term nitrogen32 versus phosphorus-based nutrient management of poul try litter. Journal of Environmental 33 Quality 37 : , 1810

– - 1816. 34
Mankin, K. R.
, and C. D. Ikenberry ( 2004

. ). " Batch reactor unvegetated wetland performance in 35 treating dairy wastewater

. ." Journal of the American Water Resources Association 40(6): 36 1527

– - 1535. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-143 Mankin, K. R.
, and C. G. Okoren

. ( 2003 ) . Field evaluation of bacteria removal in a VFS. 2003 1 ASAE Annual International Meeting . Las Vegas, NV. 2
Mankin, K. R., D. M. Ngandu, C.J. Barden, S.L. Hutchinson, and W.A. Geyer. et al. ( 2007

. ). 3

" Grass-shrub riparian buffer removal of sediment, ph osphorus, and nitrogen from 4 simulated runoff

. ." Journal of the American Water Resources Association 43(5): 1108

– - 5 1116. 6
Mankin, K. R., P. L. Barnes, J.P. Harner, P.K. Kalita, and J.E. Boyer. et al. ( 2006

. ). " Field 7 evaluation of vegetative filter effectiveness and r unoff quality from unstocked feedlots

. ." 8 Journal of Soil and Water Conservation 61: 209

– - 217. 9
Martinez, J., P. Dabert, S.Barrington, and C. Burto n. 2009. “ Livestock waste treatment systems 10 for environmental quality, food safety, and sustain ability

. ,” Bioresource Technology 11 100(22): 5527

– - 5536 12
Masse, L., D. I. Masse, and Y. Pellerin. et al. ( 2007

. ). " The use of membranes for the treatment 13 of manure: a critical literature review

. ." Biosystems Engineering 98(4): 371

– - 380. 14
McDowell, R.W., A.N. Sharpley, D.B. A.N., Beegle, and J.L. D.B., Weld

. , J.L., 2001. Comparing 15 phosphorus management strategies at a watershed sca le. J. Soil Water Conserv . 56, 306

– - 16 315. 17
McDowell, R. W
., . and D.J. Houlbrooke. 2009. “ Management options to decrease phosphorus 18 and sediment losses from irrigated cropland grazed by cattle and sheep

. ,” Soil Use and 19 Management

25(3): 224

– - 233. 20
McFarland, A.M.S., and L.M. Hauck

. , L.M., 2004. Controlling phosphorus in runoff from long 21 term dairy waste application fields. Journal of the American Water Resources Association 22 40 : , 1293

– - 1304. 23
Meals, D. W. ( 2002 ) . Water quality improvements following riparian res toration in two vermont 24 agricultural watersheds. Spring Symposium on Lake Champlain in the New Mille nnium , St 25 Jean, CANADA, Kluwer Academic/Plenum Publ. 26
Meals, D. W., J. Fay, and M. Barsotti. et al. ( 2007

. ). " Effects of water treatment residual 27 addition on phosphorus in liquid dairy manure

. ." J. Am. Water Works Assoc. 100(4): 140

– - 28 150. 29
Mejia, M. N.
, and C. A. Mandramootoo

. ( 1998

. ). " Improved Water Quality through Water 30 Table Management in Eastern Canada

. ." Journal of Irrigation and Drainage Engineering 31 124(2): 116

– - 122. 32
Melse, R. W.
, and M. Timmerman

. ( 2009

. ). " Sustainable intensive livestock production 33 demands manure and exhaust air treatment technologi es

. ." Bioresource Technology 34 100(22): 5506

– - 5511. 35
Merriman, K. R., M. W. Gitau, and I. Chaubey. et al. ( 2009

. ). " Tool for estimating best 36 management practice effectiveness in Arkansas

. ." Applied Engineering in Agriculture 37 25(2): 199

– - 213. 383/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-144 Michel, G. A., V. D. Nair, and P.K.R. Nair. et al. ( 2007

. ). " Silvopasture for reducing phosphorus 1 loss from subtropical sandy soils

. ." Plant and Soil 297: 267

– - 276. 2
Mid-Atlantic Water Program

. ( 2007

. ). “ Nutrient budgets for the Mid-Atlantic states , < ,” 3 http://www.mawaterquality.agecon.vt.edu/ >. Accessed , Retrieved February 21, 2010. 4
Minnesota Department of Agriculture and University of Minnesotat Extension ( No date). 5 Undated). " Woodchip Bioreactors

. ." Agricultural Drainage Management Coalition
, 6
< http://www.admcoalition.com/Woodbio.pdf >. Accessed , Retrieved February 21, 2010. 7
Moore, P. A., T. C. Daniel, and D.R. Edwards. et al. ( 1998 )

. Reducing phosphorus runoff and 8 inhibiting ammonia loss from poultry manure with al uminum sulfate . OECD Conference on 9 Practical and Innovative Measures for the Control o f Agricultural Phosphorus Losses to 10 Water, Antrim, North Ireland, Amer Soc Agronomy. 11
Moore, P. A., T. C. Daniel, and D.R. Edwards. et al. ( 2000

. ). " Reducing nonpoint source 12 phosphorus runoff from poultry manure with aluminum sulfate

. ." Biological Resource 13 Management: Connecting Science and Policy : 117

– - 127. 14
Morgan, K.T., K.E. Cushman, and S. K.E., Sato

. , S., 2009. Release mechanisms Mechanisms for 15 slow- and controlled Slow

- and Controlled -release fertilizers and strategies Fertilizers and 16 Strategies for their use Their Use in vegetable production Vegetable Production

. 17 Horttechnology 19 : , 10

– - 12. 18
Morrison, L. ( 2008

. ). " Nitrate neutralizer

. ." Corn and Soybean Digest March 2008. 19
Mosier, A.R., J.K. Syers, and J.R. Freney. 2004. Ch . 1-Nitrogen fertilizer: an essential 20 component of increased food, feed, and fiber produc tion. pp. 3-15. In A.R. Mosier, J.K. 21 Syers, and J.R. Freney (eds.). Agriculture and the Nitrogen Cycle . Assessing the impacts 22 and J.R. Freney (eds.). Agriculture and the Nitroge n Cycle. Assessing the impacts of 23 fertilizer use on food production and the environme nt. Scientific Committee on Problems 24 of the Environment (SCOPE). Island Press
, . Washington, DC. 25
Mulbry, W., S. Kondrad, C. Pizarro, and E. Kebede-Westhead. et al. ( 2008

. ). " Treatment of 26 dairy manure effluent using freshwater algae: Algal productivity and recovery of manure 27 nutrients using pilot-scale algal turf scrubbers

. ." Bioresource Technology 99(17): 8137

– - 28 8142. 29
Musser, W., L. Lynch, D. Johnson, N. Wallace, and K . McNew

. ( 1999

. ), “ Alternative 30 agriculture in Maryland: a guide to evaluate farm-b ased enterprises

. ,” Department of 31 Agricultural and Resource Economics, University of Maryland, 32
< http://agmarketing.extension.psu.edu/Business/PDFs/ farmaltworkbk.pdf >. Accessed
, 33 Retrieved February 21, 2010. 34
Mustafa, A., M. Scholz, R. Harrington, and P. Carroll. et al. ( 2009

. ). " Long-term performance of 35 a representative integrated constructed wetland tre ating farmyard runoff

. ." Ecological 36 Engineering 35(5): 779

– - 790. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-145 Nahm, K.H

. ., 2009. Effects of Vitamin D, Citric Acid, and Phytas e on Lowering Phosphorus 1 Levels in the Monogastric Animal Diets, Resulting i n Less Environmental Pollution. Crit. 2 Rev. Environ. Sci. Technol. 39, 521

– - 551. 3
Nair, V. D., P. K. R. Nair, R.S. Kalmbacher, and I.V. Ezenwa. et al. ( 2007

. ). " Reducing nutrient 4 loss from farms through silvopastoral practices in coarse-textured soils of Florida, USA

. ." 5 Ecological Engineering 29(2): 192

– - 199. 6
Narvanen, A., H. Jansson, J. Uusi-Kamppa, and P. Perala. et al. ( 2008

. ). " Phosphorus load from 7 equine critical source areas and its reduction usin g ferric sulphate

. ." Boreal Environment 8 Research 13(3): 265

– - 274. 9

NCAES (North Carolina Agricultural Extension Service) . 1982. Best Management Practices for 10 Agricultural Nonpoint Source Control III: Sediment. North Carolina Agricultural Extension 11 Service, in cooperation with U S EPA and USDA. Raleigh, North Carolina. 12
Needelman, B. A., D. E. Ruppert, and R.E. Vaughan. et al. ( 2006 )

. The role of ditch soil 13 formation and redox biogeochemistry in mitigating n utrient and pollutant losses from 14 agriculture . Conference on Managing Agricultural Drainage Ditc hes for Water Quality 15 Protection, College Pk, MD, Soil Water Conservation Soc. 16
Newby, L. ( 2009

. ). " Putting producers in the driver’s driver's seat

. ." Partners 27(3): 2. 17
Ng, H. Y. F., C. S. Tan, C.F. Drury, and J.D. Gaynor. et al. ( 2001

. ). " Controlled drainage and 18 subirrigation influences tile nitrate loss and corn yields in a sandy loam soil in 19 Southwestern Ontario

. ." Agriculture, Ecosystems and Environment 1758: 8. 20
Novak, J.M., and D.W. Watts

. , D.W., 2004. Increasing the phosphorus sorption capacity of 21 southeastern Coastal Plain soils using water treatm ent residuals. Soil Science 169, 206

– - 22 214. 23
Novak, J.M., and D.W. Watts

. , D.W., 2005. An alum-based water treatment residual can re duce 24 extractable phosphorus concentrations in three phos phorus-enriched coastal plain soils. 25 Journal of Environmental Quality 34 : , 1820

– - 1827. 26

USDA

- NRCS. (2002). "Part 637 environmental engineering n ational engineering 27 handbook,chapter 3 constructed wetlands." 28 http://www.wsi.nrcs.usda.gov/products/W2Q/AWM/docs/ NEH637Ch3ConstructedWetlan 29 ds.pdf , Retrieved 12/17/2009. 30
Oh, I., R. T. Burns, L.B. Mooday, and J. Lee. et al. ( 2005

. ). " Optimization of phosphorus 31 partitioning in dairy manure using chemical additiv es with a mechanical solids separator

. ." 32 Transactions of the ASAE Asae 48(3): 1235

– - 1240. 33
Osei, E., B. Du, A. B., Bekele, L. A., Hauck, A. L., Saleh, and A

. ., Tanter

. , A., 2008. Impacts of 34 alternative manure application rates on Texas anima l feeding operations: A macro level 35 analysis. Journal of the American Water Resources Association 44 : , 562

– - 576. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-146 Osmond, D. L., D. M. Butler, N.N. Ranells, M.H. Poore, A. Wossink, and J.T. Gree n. et al. 1 ( 2007 ) " Grazing Practices: A Review of the Literature

. ." Technical Bulletin 325-W, North 2 Carolina Agricultural Research Service, NC State Un iversity. 3
Owens, L. B.
, and M. J. Shipitalo

. ( 2009

. ). " Runoff quality evaluations of continuous and 4 rotational over-wintering systems for beef cows

. ." Agriculture Ecosystems & Environment 5 129(4): 482

– - 490. 6
Penn, C.J., G.L. Mullins, G. L. W.
, Zelazny, J.G. L.W., Warren, and J. M. G., McGrath

. , J.M., 2004. 7 Surface runoff losses of phosphorus from Virginia s oils amended with turkey manure using 8 phytase and high available phosphorus corn diets. Journal of Environmental Quality 33 : , 9 1431

– - 1439. 10
Pennsylvania State University. 1997. T he Penn State Agronomy Guide, 1997- 1998. 11 Pennsylvania State University, University Park, PA. 12
Peterson, J. R., D. C. Flanagan, and J.K. Tishmack. 2002. et al. (2002). " PAM application 13 method and electrolyte source effects on plot-scale runoff and erosion

. ." Transactions of 14 the ASAE

Asae 45(6): 1859

– - 1867. 15
Peterson, J. R., D. C. Flanagan, and J.K. Tishmack. 2002. et al. (2002). " Polyacrylamide and 16 gypsiferous material effects on runoff and erosion under simulated rainfall

. ." Transactions 17 of the ASAE

Asae 45(4): 1011

– - 1019. 18
Pote, D.H., T.C. Daniel, A.N. T.C., Sharpley, P. A. N., Moore, D.R. P.A., Edwards, and D. J. R., 19 Nichols

. , D.J., 1996. Relating extractable soil phosphorus to phos phorus losses in runoff. 20 Soil Sci. Soc. Am. J. 60 : , 855–859. 21
Pote, D.H., W.L. Kingery, G.E. W.L., Aiken, F.X. G.E., Han, P.A. F.X., Moore, and K. P.A., 22 Buddington

. , K., 2003. Water-quality effects of incorporating poult ry litter into perennial 23 grassland soils. Journal of Environmental Quality 32 : , 2392

– - 2398. 24
Pote, D.H., T.R. Way, K T .R

. ., Sistani, and P.A. K.R., Moore

. , P.A., 2009. Water-quality effects 25 of a mechanized subsurface-banding technique for ap plying poultry litter to perennial 26 grassland. Journal of Environmental Management 90 : , 3534

– - 3539. 27
Powers, W., and R. Angel

. , R., 2008. A review of the capacity for nutritional str ategies to 28 address environmental challenges in poultry product ion. Poult. Sci . 87 : , 1929-1938. 29
Prado, N., J. Ochoa, and A. Amrane. 2009. et al. (2009). " Zero Nuisance Piggeries: Long-term 30 performance of MBR (membrane bioreactor) for dilute swine wastewater treatment using 31 submerged membrane bioreactor in semi-industrial sc ale

. ." Water Research 43(6): 1549

– - 32 1558. 33
Prantner, S. R., R. S. Kanwar, J.C. Lorimor, and C.H. Pederson. et al. ( 2001

. ). " Soil infiltration 34 and wetland microcosm treatment of liquid swine man ure

. ." Applied Engineering in 35 Agriculture 17(4): 483

– - 488. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-147 Puustinen, M., J. Koskiaho, and K. Peltonen. et al. ( 2005

. ). " Influence of cultivation methods on 1 suspended solids and phosphorus concentrations in s urface runoff on clayey sloped fields 2 in boreal climate

. ." Agriculture Ecosystems & Environment 105(4): 565

– - 579. 3
Qiu, Z., C. Hall, and K. Hale. 2009. et al. (2009). " Evaluation of cost-effectiveness of 4 conservation buffer placement strategies in a river basin

. ." Journal of Soil and Water 5 Conservation 64(5): 293

– - 302. 6
Ra, C. S., J. S. Shin, J.S. Oh, I.S. Yuh, and B.J. Hong. et al. ( 1998

. ). " Technology for the 7 optimization of animal wastewater treatment efficie ncies and costs

. ." Korean Journal of 8 Animal Science 40(6): 691

– - 700. 9
Rasse, D. P., J. T. Ritchie, W.R. Peterson, J. Wei, and A.J.M. Smucker. et al. ( 2000

. ). " Rye 10 cover crop and nitrogen fertilization effects on ni trate leaching in inbred maize fields

. ." 11 Journal of Environmental Quality 29(1): 298

– - 304. 12
Read, J. J., K. R. Sistani, J.L. Oldham, and G.E. Brink. 2009. et al. (2009). " Double-cropping 13 annual ryegrass and bermudagrass to reduce phosphor us levels in soil with history of 14 poultry litter application

. ." Nutrient Cycling in Agroecosystems 84(1): 93

– - 104. 15
Reiman, M., D.E. Clay, C.G. D.E., Carlson, S.A. C.G., Clay, G. S.A., Reicks, D.W. G., Clay, and 16 D. E. W., Humburg

. , D.E., 2009. Manure placement depth impacts on crop yield s and N 17 retained in soil. Journal of Environmental Science and Health Part B- Pesticides Food 18 Contaminants and Agricultural Wastes 44 : , 76

– - 85. 19
Risse, L.M., and J.E. Gilley , J.E., 2000. Manure impacts on runoff and soil loss. Animal, 20 Agricultural and Food Processing Wastes
, 578

– - 587. 21
Ritter, W.F., J. Kulkarni, L.M. Ward, and A. Banerj ee. 2003. Potential for reducing nutrient 22 loads to the Chesapeake Bay with improved livestock waste management, Ninth 23 International Animal, Agricultural and Food Process ing Wastes Proceedings, 12-15 Oct. 24 2003, Research Triangle Park, NC, pp. 1

– - 8. 25
Robertson, W. D.
, and L. C. Merkley

. ( 2009

. ). " In-Stream Bioreactor for Agricultural Nitrate 26 Treatment

. ." Journal of Environmental Quality 38(1): 230

– - 237. 27
Robertson, W. D. and L. C. Merkley

. ( 2009

. ). " In-Stream Bioreactor for Agricultural Nitrate 28 Treatment

. ." Journal of Environmental Quality 38(1): 230

– - 237. 29
Robertson, W. D., D. W. Blowes, C.J. Ptacek, and J.A. Cherry. et al. ( 2000

. ). " Long-Term 30 Performance of In Situ Reactive Barriers for Nitrat e Remediation

. ." Ground Water 38(5): 31 7. 32
Russell, J.R
., . and L.A. Christensen. 1984. Use and Cost of Soil Conservation and Water 33 Quality Practices in the Southeast. U.S. Department of Agriculture, Economic Research 34 Service, Washington, DC. 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-148 Saleh, A., E. Osei, D.B. Jaynes, B. Du, and J.G. Arnold. et al. ( 2005 ) . Economic and 1 environmental impacts of LSNT and cover crops for n itrate-nitrogen reduction in Walnut 2 Creek watershed, Iowa, using fem and enhanced SWAT models. Annual Meeting of the 3 American-Society-of-Agricultural-and-Biological-Eng ineers , Madison, WI, Amer Soc 4 Agricultural & Biological Engineers. 5
Sanders, J.H., D. Valentine, E. Schaeffer, D. Green e, and J. McCoy. 1991. Double Pipe Creek 6 RCWP: Ten Year Report. U.S. Department of Agriculture, University of Maryl and 7 Cooperative Extension Service, Maryland Department of the Environment, and Carroll 8 County Soil Conservation District. 9
Sands, G. R., I. Song, L.M. Busman, and B.J. Hansen. et al. ( 2008

. ). " The Effects of Subsurface 10 Drainage Depth and Intensity on Nitrate Loads in th e Northern Cornbelt

. ." 51(3): 937

– - 11 946. 12
Schaafsma, J. A., A. H. Baldwin, and C.A. Streb. et al. ( 2000

. ). " An evaluation of a constructed 13 wetland to treat wastewater from a dairy farm in Ma ryland, USA

. ." Ecological Engineering 14 14(1

– - 2): 199

– - 206. 15
Sharma, N. C.
, and S. V. Sahi

. ( 2005

. ). " Characterization of phosphate accumulation in Loliu m 16 multiflorum for remediation of phosphorus-enriched soils

. ." Environmental Science & 17 Technology 39(14): 5475

– - 5480. 18
Sharpey, A.N

. ., 1995. Dependence of runoff phosphorus on extractab le soil phosphorus. J. 19 Environ. Qual. 24, 920–926. 20
Shi, Y., D. B. Parker, N.A. Cole, B.W. Auvermann, and J.E. Mehlhorn. et al. ( 2001

. ). " Surface 21 amendments to minimize ammonia emissions from beef cattle feedlots

. ." Transactions of 22 the ASAE

Asae 44(3): 677

– - 682. 23
Shigaki, F., P. J. A. Kleinman, J.P. Schmidt, A.N. Sharpley, and A.L. Allen. et al. ( 2008

. ). 24

" Impact of Dredging on Phosphorus Transport in Agric ultural Drainage Ditches of the 25 Atlantic Coastal Plain

. ." Journal of the American Water Resources Association 44(6): 26 1500

– - 1511. 27
Shoji, S., J. Delgado, A. J., Mosier, and Y. A., Miura

. , Y., 1999. Use of controlled release 28 fertilizers and nitrification inhibitors to increas e nitrogen use efficiency and to conserve air 29 and water quality. Annual Conference of the Soil-an d-Water-Conservation-Society. Marcel 30 Dekker Inc, Biloxi, Mississippi, pp. 1051

– - 1070. 31
Singer, J. W., C. A. Cambardella, and T.B. Moorman. et al. ( 2008

. ). " Enhancing Nutrient 32 Cycling by Coupling Cover Crops with Manure Injecti on

. ." Agronomy Journal 100(6): 33 1735

– - 1739. 34
Singh, A., K.D. Casey, W. D. King, A.J. Pescatore, R.S. Gates, and M.J. Ford. 2009. “ Efficacy 35 of urease inhibitor to reduce ammonia emission from poultry houses

. ,” Journal of Applied 36 Poultry Research 18(1): 34

– - 42. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-149 Sistani, K. R., G. E. Brink, and J.L. Oldham. et al. ( 2008

. ). " Managing broiler litter application 1 rate and grazing to decrease watershed runoff losse s

. ." Journal of Environmental Quality 2 37(2): 718

– - 724. 3
Sistani, K. R., H. A. Torbert, T.R. Way, C.H. Bolster, D.H. Pote, and J.G. Warren. et al. ( 2009

. ). 4

" Broiler Litter Application Method and Runoff Timing Effects on Nutrient and Escherichia 5 coli Losses from Tall Fescue Pasture

. ." Journal of Environmental Quality 38(3): 1216

– - 6 1223. 7 Skaggs, R. W. and M. A. Youssef

. ( 2008

. ). " Effect of Drainage Water Management on Water 8 Conservation and Nitrogen Losses to Surface Waters

. ." Paper presented at 16 th National 9 Nonpoint Source Monitoring Workshop, September 14

– - 18, 2008, Columbus, OH. 10
Skaggs, R. W., M. A. Youssef, G.M. Chescheir, and J.W. Gilliam. et al. ( 2005

. ). " Effect of 11 Drainage Intensity on Nitrogen Losses from Drained Lands

. ." Transactions of the ASAE 12 48(6): 2169

– - 2177. 13
Smeltz, H. L., R. O. Evans, D.L. Osmond, and G.D. Jennings. et al. ( 2005

. ). " Nitrate Reduction 14 Through Controlled Drainage & Nutrient Management P lans

. ." ASAE Meeting Paper No. 15 052236, St. Joseph, MI 2005 ASAE Annual Internation al Meeting, Tampa: 12. 16
Smith, D. R., E. A. Warnemuende, C. Huang, and G.C. Heathman. et al. ( 2007

. ). " How does the 17 first year tilling a long-term no-tillage field imp act soluble nutrient losses in runoff ? ?" Soil 18 & Tillage Research 95(1

– - 2): 11

– - 18. 19
Smith, D. R., P. A. Moore, C.L. Griffis, T.C. Daniel, D.R. Edwards, and D.L. B oothe. et al. 20 ( 2001

. ). " Effects of alum and aluminum chloride on phosphorus runoff from swine 21

manure

. ." Journal of Environmental Quality 30(3): 992

– - 998. 22
Smith, D.R., Moore, P.A., Miles, D.M., Haggard, B.E ., Daniel, T.C

. ., 2004. Decreasing 23 phosphorus runoff losses from land-applied poultry litter with dietary modifications and 24 alum addition. Journal of Environmental Quality 33 : , 2210

– - 2216. 25
Smith, E., R. Gordon, A. Madani, and G. Stratton. et al. ( 2006

. ). " Year-round treatment of dairy 26 wastewater by constructed wetlands in Atlantic Cana da

. ." Wetlands 26(2): 349

– - 357. 27
Smolen, M.D. and F.J. Humenik. 1989. National Water Quality Evaluation Project 1988 Annu al 28 Report: Status of Agricultural Nonpoint Source Proj ects

. EPA-506/9-89/002. U.S. 29 Environmental Protection Agency
, and U.S. Department of Agriculture, Washington, DC

. 30 EPA

- 506/9

- 89/002. 31
Sojka, R

. ., 2009. Matrix-based fertilizer: A new fertilizer for mulation concept to reduce nutrient 32 leaching . In Proceedings of the New Zealand Lime and Fertilizer Institute Workshop

. 33
Sommer, S.G., M . M aahn, H.D. M., Poulsen, M. H.D., Hjorth, and J. M., Sehested

. , J., 2008. 34 Interactions between phosphorus feeding strategies for pigs and dairy cows and separation 35 efficiency of slurry. Environmental Technology 29 : , 75

– - 80. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-150 Sotomayor-Ramirez, D., G. A. Martinez, J. Ramirez-Avila, and E. Mas. et al. ( 2008

. ). 1

" Effectiveness of grass filter strips for runoff nut rient and sediment reduction in dairy 2 sludge-amended pastures

. ." Journal of Agriculture of the University of Puerto Rico 92(1

– - 3 2): 1

– - 14. 4
Staats, K.E., Y. Arai, and D.L. Y., Sparks

. , D.L., 2004. Alum amendment effects on phosphorus 5 release and distribution in poultry litter-amended sandy soils. Journal of Environmental 6 Quality 33 : , 1904

– - 1911. 7
Staver, K. W. and R. B. Brinsfield

. ( 1998

. ). " Using cereal grain winter cover crops to reduce 8 groundwater nitrate contamination in the mid-Atlant ic coastal plain

. ." Journal of Soil and 9 Water Conservation 53(3): 11. 10
Stout, W. L., S. L. Fales, L.D. Muller, R.R. Schnabel, G.F. Elwinger, and S.R. Weaver. et al. 11 ( 2000

. ). " Assessing the effect of management intensive grazin g on water quality in the 12 northeast US

. ." Journal of Soil and Water Conservation 55(2): 238

– - 243. 13
Sullivan, T. J., J. A. Moore, D.R. Thomas, E. Mallery, K.U. Snyder, M. Wustenberg , J. 14 Wustenberg, S.D. Mackey, and D.L. Moore. et al. ( 2007

. ). " Efficacy of vegetated buffers 15 in preventing transport of fecal coliform bacteria from Pasturelands

. ." Environmental 16 Management

40(6): 958

– - 965. 17
Swink, S. N., Q. M. Ketterings, L.E. Chase, K.J. Czymmek, and J.C. Mekken. et al. ( 2009

. ). 18

" Past and future phosphorus balances for agricultura l cropland in New York State

. ." 19 Journal of Soil and Water Conservation 64(2): 120

– - 133. 20
Szogi, A. A.
, and M. B. Vanotti

. ( 2007

. ). " Abatement of ammonia emissions from swine 21 lagoons using polymer-enhanced solid-liquid separat ion

. ." Applied Engineering in 22 Agriculture 23(6): 837

– - 845. 23
Tan, C. S., C. F. Drury, T.Q. Zhang, W.D. Reynolds, and J.D. Gaynor. et al. ( 2003

. ). " Wetland - 24 Reservoir System Improves Water Quality and Crop Pr oduction

. ." ASAE Meeting Paper 25 No. 032327, St. Joseph, MI 2003 ASAE Annual Interna tional Meeting, Las Vegas: 9. 26
Tan, C. S., C. F. Drury, J.D. Gaynor, W.D. Reynolds, T.W. Welacky, and T.Q. Zhang. et al. 27 ( 2004

. ). " Effect of Water Table Management on Water Quality a nd Crop Yield at the Plot 28 and Farm Scale Fields

. ." ASAE-CIGR Meeting Paper No. 042241, St. Joseph, MI 2004 29 ASAE Annual International Meeting, Ottawa: 10. 30
Tanner, C. C., M. L. Nguyen, and J.P.S. Sukias. et al. ( 2005

. ). " Nutrient removal by a 31 constructed wetland treating subsurface drainage fr om grazed dairy pasture

. ." Agriculture 32 Ecosystems & Environment 105(1

– - 2): 145

– - 162. 33
Tate, K. W., G. A. Nader, D.J. Lewis, E.R. Atwill, and J.M. Connor. et al. ( 2000

. ). " Evaluation 34 of buffers to improve the quality of runoff from ir rigated pastures

. ." Journal of Soil and 35 Water Conservation 55(4): 473

– - 478. 36
Thorstensen, H. (No date ). ) " System seems to reduce harmful field runoff

. ." Agri News

. 373/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-151 Trask, J. R., P. K. Kalita, M.S. Kuhlenschmidt, R.D. Smith, and T.L. Funk. et al. ( 2004

. ). 1

" Overland and Near-Surface Transport of Cryptosporid ium parvum from Vegetated and 2 Nonvegetated Surfaces

. ." Journal of Environmental Quality 33: 984

– - 993. 3
Trias, M., Z. Hu, M.M. Mortula, R.J. Gordon, and G.A. Gagnon. et al. ( 2004

. ). " Impact of 4 seasonal variation on treatment of swine wastewater

. ." Environmental Technology 25(7): 5 775

– - 781. 6
Turtola, E., L. Alakukku, R. Uusitalo, and A. Kaseva. et al. ( 2007

. ). " Surface runoff, subsurface 7 drainflow and soil erosion as affected by tillage i n a clayey Finnish soil

. ." Agricultural and 8 Food Science 16(4): 332

– - 351. 9
Ullman, J. L., S. Mukhtar, R.E. Lacey, and J.B. Carey. et al. ( 2004

. ). " A review of literature 10 concerning odors, ammonia, and dust from broiler pr oduction facilities: 4. Remedial 11 management practices

. ." Journal of Applied Poultry Research 13(3): 521

– - 531. 12

USDA-ARS (U.S. Department of Agriculture–Agricultural Resea rch Service) . 2005. “ Revised 13 Universal Soil Loss Equation 2 - Overview of RUSLE2
, ,” USDA-Agricultural Research 14 Service . < , http://www.ars.usda.gov/Research/docs.htm?docid=601 0 >. Accessed , Retrieved 15 February 21, 2010. 16

USDA–NRCS (U.S. Department of Agriculture–Natural Resources Conservation Service) . 1977. 17 National Handbook of Conservation Practices. Natural Resources Conservation Service 18 (formerly Soil Conservation Service), U.S. Departme nt of Agriculture, Washington, 19 DC.< http://www.ncg.nrcs.usda.gov/index.html>. 20
http://www.ncg.nrcs.usda.gov/ index.html> 21
USDA-NRCS ( U.S. Department of Agriculture–Natural Resources Co nservation Service). 2002. 22 Part 637 environmental engineering national enginee ring handbook,chapter 3 constructed 23 wetlands

. 24 <http://www.wsi.nrcs.usda.gov/products/W2Q/AWM/docs /NEH637Ch3ConstructedWetla 25 nds.pdf>. Accessed 12/17/2009. 26
USDA-NRCS (U.S. Department of Agriculture–Natural R esources Conservation Service). 2008

. 27 ). " Surface Drainage, Field Ditch 607-1

. ." Electronic Field Office Technical Guide28 Maryland

. 29
USDA-NRCS ( U.S. Department of Agriculture–Natural Resources Co nservation Service). 2010

. 30 ) . “ Save energy, save money, conservation practices tha t save: crop residue management

. 31
< .” http://www.nrcs.usda.gov/technical/energy/cropres.h tml >. Accessed , retrieved 32 February 21, 2010. 33

USEPA (U.S. Environmental Protection Agency) . 2003. National Management Measures 34 “National management measures for the Control of Nonpoint Pollution control of nonpoint 35 pollution from Agriculture

. agriculture,” http://www.epa.gov/nps/agmm/, EPA-841-B-03- 36 004, U.S. Environmental Protection Agency, Office o f Water, Washington, DC. 37 <http://www.epa.gov/nps/agmm/>. Accessed February 2 1, 2010. 383/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-152 USEPA (U.S. Environmental Protection Agency) . 2005. “ National management measures to 1 protect and restore wetlands and riparian areas for the abatement of nonpoint source 2 pollution, ” EPA-841-B-05-003, U.S. Environmental Protection Age ncy, Office of Water, 3 Washington, DC, < http://www.epa.gov/nps/wetmeasures/pdf/guidance.pdf >. Accessed
, 4 Retrieved February 21, 2010. 5
Uusi-Kamppa, J. ( 2006

. ). " Vegetated buffer zones for agricultural non-point s ource pollution 6 control

. ." Soil Management for Sustainability 38: 337

– - 343. 7
Uusitalo, R., E. Turtola, and R. Lemola. et al. ( 2007

. ). " Phosphorus losses from a subdrained 8 clayey soil as affected by cultivation practices

. ." Agricultural and Food Science 16(4): 9 352

– - 365. 10
van der Meer, H. G. 2008. “ Optimising manure management for GHG outcomes

. ,” Australian 11 Journal of Experimental Agriculture 48(1

– - 2): 38

– - 45. 12
van Driel, P. W., W. D. Robertson, and L.C. Merkley. et al. ( 2006

. ). " Denitrification of 13 agricultural drainage using wood-based reactors

. ." American Society of Agricultural and 14 Biological Engineers 49(2): 9. 15
van Vliet, L. J. P., B. J. Zebarth, and G. Derksen. 2002. et al. (2002). " Effect of fall-applied 16 manure practices on runoff, sediment, and nutrient surface transport from silage corn in 17 south coastal British Columbia

. ." Canadian Journal of Soil Science 82(4): 445

– - 456. 18
van Vliet, L.J.P., S. Bittman, G. S., Derksen, and C. G

. ., Kowalenko

. , C.G., 2006. Aerating 19 grassland before manure application reduces runoff nutrient loads in a high rainfall 20 environment. Journal of Environmental Quality 35 : , 903

– - 911. 21
Vanotti, M. B.
, and A. A. Szogi

. ( 2008

. ). " Water quality improvements of wastewater from 22 confined animal feeding operations after advanced t reatment

. ." Journal of Environmental 23 Quality 37(5): S86

– - S96. 24
Vanotti, M. B., A. A. Szogi, P.D. Millner, and J.H. Loughrin. 2009. et al. (2009). " Development 25 of a second-generation environmentally superior tec hnology for treatment of swine manure 26 in the USA

. ." Bioresource Technology 100(22): 5406

– - 5416. 27
Vanotti, M. B., D. M. C. Rashash, and P.G. Hunt. 2002. et al. (2002). " Solid-liquid separation of 28 flushed swine manure with PAM: Effect of wastewater strength

. ." Transactions of the 29 ASAE

Asae 45(6): 1959

– - 1969. 30
Vanotti, M. B., J. M. Rice, A.Q. Ellison, P.G. Hunt, F.J. Humenik, and C.L. Bai rd. et al . ( 2005

. ). 31

" Solid-liquid separation of swine manure with polyme r treatment and sand filtration

. ." 32 Transactions of the ASAE Asae 48(4): 1567

– - 1574. 33
Warren, J.G., K.R. Sistani, T K .R

. ., Way, D.A. T.R., Mays, and D. H A., Pote

. , D.H., 2008. A New 34 Method of Poultry Litter Application to Perennial P asture: Subsurface Banding. Soil 35 Science Society of America Journal 72 : , 1831

– - 1837. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-153 Weber, D., A. Drizo, E. Twhohig, S. Bird, and D. Ross. et al. ( 2007

. ). " Upgrading constructed 1 wetlands phosphorus reduction from a dairy effluent using electric arc furnace steel slag 2 filters

. ." Water Science and Technology 56(3): 135

– - 143. 3
White, J. R., K. R. Reddy, and J. Majer-Newman. et al. ( 2006

. ). " Hydrologic and vegetation 4 effects on water column phosphorus in wetland mesoc osms

. . " Soil Science Society of 5 America Journal 70(4): 1242

– - 1251. 6
Wood, J. D., R. Gordon, A. Madani, and G.W. Stratton. et al. ( 2008

. ). " A long term assessment 7 of phosphorus treatment by a constructed wetland re ceiving dairy wastewater

. ." Wetlands 8 28(3): 715

– - 723. 9
Woodbury, B. L., J. A. Nienaber, and R.A. Eigenberg. et al. ( 2000

. ). " Evaluation of a passive 10 feedlot runoff control treatment system

. ." Animal, Agricultural and Food Processing 11 Wastes : 266

– - 272. 12
Woodbury, B. L., J. A. Nienaber, and R.A. Eigenberg. 2002. et al. (2002). " Operational 13 evaluation of a passive beef cattle feedlot runoff control and treatment system

. ." Applied 14 Engineering in Agriculture 18(5): 541

– - 545. 15
Woodbury, B. L., J. A. Nienaber, and R.A. Eigenberg. et al. ( 2003

. ). " Performance of a passive 16 feedlot runoff control and treatment system

. ." Transactions of the ASAE Asae 46(6): 1525

– - 17 1530. 18
Wossink, A. ( 2001

. ). " Cost and Benefits of Best Management Practices to C ontrol Nitrogen in 19 the Piedmont . <http://www.neuse.ncsu.edu/Piedmont_costs.pdf>. A ccessed December 1, 20 2009 ." Retrieved December 1, 2009, from http://www.neus e.ncsu.edu/Piedmont_costs.pdf

. 21
Wossink, A.
, and D. Osmond. ( 2001

. ). " Cost and Benefits of Best Management Practices to 22 Control Nitrogen in the Lower Coastal Plain

. ." 8/01—2M—JL/VG AG-620, E01-38976 23 <http://www.neuse.ncsu.edu/Ag%20620.pdf>. Accessed December 1, 2009 Retrieved 24 December 1, 2009, from http://www.neuse .ncsu.edu/Ag%20620.pdf

. 25
Yang, P. Y., H.J. Chen, and S.J. Kim. 2003. “ Integrating entrapped mixed microbial cell 26 (EMMC) process for biological removal of carbon and nitrogen from dilute swine 27 wastewater

. ,” Bioresource Technology 86(3): 245

– - 252. 28
Yongabi, K. A., P. L. Harris, and D.M. Lewis. 2009. et al. (2009). " Poultry faeces management 29 with a simple low cost plastic digester

. ." African Journal of Biotechnology 8(8): 1560

– - 30 1566. 31
Yuan, Y., S. M. Dabney, and R.L. Bingner. 2002. et al. (2002). " Cost effectiveness of 32 agricultural BMPs for sediment reduction in the Mis sissippi Delta

. ." Journal of Soil and 33 Water Conservation 57(5): 259

– - 267. 34
Zeneca Ag Products. 1994. Conservation farming - a practical handbook for cot ton growers, 35 Zeneca, Inc., USA, 42 pp. 363/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-154 Zhou, X., M. J. Helmers, M. Al-Kaisi, and H.M. Hanna. 2009. et al. (2009). " Cost-effectiveness 1 and cost-benefit analysis of conservation managemen t practices for sediment reduction in 2 an Iowa agricultural watershed

. ." Journal of Soil and Water Conservation 64(5): 314

– - 323. 3
Zvomuya, F., C.J. Rosen, and S. C. J., Gupta

. , S.C., 2006. Phosphorus sequestration by chemical 4 amendments to reduce leaching from wastewater appli cations. Journal of Environmental 5 Quality 35 : , 207

– - 215. 6

7

8

9

10

11 (POTENTIAL AND LIMITATIONS OF COVER C ROPS, LIVING MULCHES, AND 12 PERENNIALS TO REDUCE NUTRIENT LOSSES TO WATER SOURC ES FROM 13 AGRICULTURAL FIELDS 14 T.C. Kaspar, Plant Physiologist, USDA

- ARS, National Soil Tilth Laboratory; 15 E.J. Kladivko, Professor of Soil Physics, Agronomy Dept., Purdue University; 16 J.W. Singer, Research Agronomist, USDA

- ARS, National Soil Tilth Laboratory 17 S. Morse, Senior Fellow, Agronomy/Plant Genetics, U niversity of Minnesota 18 D. Mutch, Cover Crops/Field Crops IPM Specialist, K BS, Michigan State University 19 http://www.epa.gov/msbasi n/pdf/10covercrops.pdf Gulf Hypoxia and Local Water Quality 20 Concerns Workshop , September 26

- 28, 2005, Ames, IA) 21 [CONTROLLED DRAINAGE MANAGEMENT GUIDELINES FOR IMPR OVING 22 DRAINAGE WATER QUALITY Prepared by: 23 Robert Evans, Extension Agricultural Engineering Sp ecialist 24 J.W. Gilliam, Professor of Soil Science 25 Wayne Skaggs, William Neal Reynolds Professor 26 Department of Biological and Agricultural Engineeri ng 27 Published by: North Carolina Cooperative Extension Service 28
Publication Number: AG 443 29
Last Electronic Revi sion: June 1996 (KNS)] 30 Hartwig, N.L., and H.U. Ammon. 2002. Cover crops an d living mulches. Weed Sci. 50:688

- 699. 31 (POTENTIAL AND LIMITATIONS OF COVER CROPS, LIVING M ULCHES, AND 32 PERENNIALS TO REDUCE NUTRIENT LOSSES TO WATER SOURC ES FROM 33 AGRICULTURAL FIELDS 34 T.C. Kaspar, Plant Physiologist, USDA

- ARS, National Soil Tilth Laboratory; 353/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-155 E.J. Kladivko, Professor of Soil Physics, Agronomy Dept., Purdue University; 1 J.W. Singer, Research Agronomist, USDA

- ARS, National Soil Tilth Laboratory 2 S. Morse, Senior Fellow, Agro nomy/Plant Genetics, University of Minnesota 3 D. Mutch, Cover Crops/Field Crops IPM Specialist, K BS, Michigan State University 4 http://www.epa.gov/msbasin/pdf/10covercrops.pdf Gulf Hypoxia and Local Water Quality 5 Concerns Workshop , September 26

- 28, 2005, Ame s, IA) 6 [CONTROLLED DRAINAGE MANAGEMENT GUIDELINES FOR IMPR OVING 7 DRAINAGE WATER QUALITY Prepared by: 8 Robert Evans, Extension Agricultural Engineering Specialist 9 J.W. Gilliam, Professor of Soil Science 10 Wayne Skaggs, William Neal Reynolds Professor 11 Depart

ment of Biological and Agricultural Engineering 12 Published by: North Carolina Cooperative Extension Service 13
Publication Number: AG 443 14 Last Electronic Revision: June 1996 (KNS)] 15 Blackmer, A.M. and A.P. Mallarino. 1996. Cornstalk Testing to Evaluate Nitroge n Management 16 (PM

- 1584). Iowa State Univ. Extension. This page provides links to nutrient management 17 training courses including the P index, information on nutrient management consultant 18 certification, manure sampling and analysis methods , and related websi tes. 193/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote —

Chapter 2. Agriculture 2-156 

## Appendix 1: USDA Conservation Practice Standards 1 

## (Practice Codes) Referenced throughout the document 2
32

- 22

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— Do Not Cite or Quote

—

Chapter 2. Agriculture 2-1642

- 22

- 10 Chesapeake Bay Ex ecutive Order Section 502 Guidance

— Do Not Cite or Quote

—

Chapter 2. Agriculture 2-165 

## Appendix 2: Agricultural Tools in Support of Sectio n 502 1 

## Technical Guidance 2 Included in this appendix are summaries of online t ools that can be used by producers, planners, 3 and managers to develop plans for these practices. 4

The tools and resources summarized in this table an d described below are not intended to 5 provide push

- button farm management plans that will solve all of the environmental problem s 6 addressed by the Section 502 Technical Guidance. Rather, these tools are generally used by 7 experts (e.g., USDA field technicians and engineers ) to work with clients to design appropriate 8 conservation plans for their lands. When developing management plans for their operatio ns, 9 producers generally rely on a range of information and expertise derived from USDA, 10 universities, soil and water conservation districts , other producers, and the private sector. A 11 range of tools and resources are summarized in the Table below and represent those that are 12 generally used by experts (e.g., USDA field technic ians and engineers) to work with clients to 13 design appropriate conservation plans for their lan ds. Most of the tools listed below are available 14 for free. 15

16

# Tool name Name and document link Document Link Applicable practices a Practices 1 Source and Web link Link

Software and Models
1 NuMan Pro NM Univ. Maryland
2 AFOPro NM, AWM Univ. South Carolina
3 Animal Waste Management Software AWM USDA-NRCS
4 Manure Management Planner (MMP) Software

— AWM, NM Purdue University

5 National Nutrient Management Data Download NM, AWM Univ. Missouri

6 Spatial Nutrient Management Planner NM, AWM Univ. Missouri
7 Win Max NM, AWM Purdue University
8 MapWindow GIS + MMP Tools AWM, NM Purdue University
9 Manure Master Decision Support System AWM, NM USDA-NRCS
10 Revised Universal Soil Loss Equation, Version 2 (RUSLE2) ESC USDA-NRCS

11 Using RUSLE2 for the Design and Predicted Effectiveness of Vegetative Filter Strips (VFS) for Sediment ESC USDA-NRCS

12 Vegetative Filter Strip Modeling System (VFSMOD) ESC Univ. Florida

13 Integrated Farm System Model (IFSM) AWM, NM, ESC, GM USDA-ARS
14 Dairy Greenhouse Gas Model (DairyGHG) AWM, NM USDA-ARS

15 Cropware NM, AWM Cornell Univ.
16 Soil Test Conversion Tools NM Cornell Univ.2

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Chapter 2. Agriculture 2-166 # Tool name Name and document

link Document Link Applicable practices a Practices 1 Source and Web link Link

17 Great Plains Framework for Agricultural Resource Management (GPFARM) AWM, NM, ESC, GM USDA-ARS

18 Soil - Plant - Atmosphere—Water Field & Pond Hydrology (SPAW) DWM USDA-ARS

Calculators, Spreadsheets, and Graphical Tools 19 Dairy Cattle N Excretion Calculator AWM, NM Cornell Univ.
20 Corn N Calculator NM Cornell Univ.
21 Total N Available from Manure Applications AWM, NM Cornell Univ.

22 Other Calculators AWM, NM Cornell Univ.
23 Nutrient Management Spreadsheets AWM, NM Univ. Delaware
24 Crop Nutrient Tool NM USDA-NRCS
25 Crop Fertilizer Recommendation Calculator NM Purdue Univ.

26 Manure Nutrient Availability Calculator AWM, NM Purdue Univ.
27 Conservation Buffers ESC USDA-National Agroforestry Center
28 Farm*A*Syst AWM, NM Univ. Wisconsin Compilations of Tools 29 Technical Resources Main Page AWM, DWM, ESC, GM, NM USDA-NRCS

30 Animal Feeding Operations (AFO) Virtual Information Center AWM, NM USEPA

31 Software Products AWM, DWM, ESC, GM, NM USDA-ARS

32 Nutrient Management Planning Software and Support NM, AWM Univ. Missouri

Guidance and Other Technical Resources 33 Nutrient and Pest Management Tools and Information NM USDA-NRCS

34 Conservation Practices AWM, DWM, ESC, GM, NM USDA-NRCS

35 Agronomy and Erosion ESC USDA-NRCS
36 Animal Feeding Operations AWM, NM USDA-NRCS
37 Nutrient Management Technical Notes NM, AWM USDA-NRCS
38 National Range and Pasture Handbook GM, ESC USDA-NRCS
39 Phosphorus Index NM USDA-NRCS
40 SERA-17 Publications and BMP Fact Sheets NM SERA-17

41 Managing Cover Crops Profitably, 3rd Edition Cover Crops SARE

42 Precision Feed Management Certification for Dairy Professionals AWM, NM Mid-Atlantic Water Program
43 Mid-Atlantic Better Composting School AWM, NM Mid-Atlantic Water2

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Chapter 2. Agriculture 2-167 # Tool name Name and document

link Document Link Applicable practices a Practices 1 Source and Web link Link

Program
44 Environmental Management System for Manure AWM Mid-Atlantic Water Program
45 Mid-Atlantic Nutrient Management Handbook NM Mid-Atlantic Water Program
46 Information on Nutrient and Sediment Best Management Practices NM, ESC Chesapeake Bay Program

47 Fact Sheets NM, AWM Univ. Delaware
48 Nutrient Management NM MD Dept. Agriculture
49 Nutrient Management Program NM Univ. Maryland
50 Nutrient Management Plan Writing Tools NM Univ. Maryland
51 Phosphorus Site Index NM Univ. Maryland
52 Nutrient Management Software and Publications NM Univ. Maryland

53 Nutrient Management Spear Program AWM, NM Cornell Univ.
54 Manure Management AWM, NM Penn State Univ

. 55 Pennsylvania Nutrient Management Program NM Penn State Univ.

56 Planning Tools and Resources NM Penn State Univ.
57 Nutrient Management Technical Manual NM, AWM Penn State Univ

. 58 Educational Materials NM, AWM Penn State Univ

. 59 Fact Sheets on Agriculture and Environmental Quality NM, AWM, GM Virginia Tech Univ

.

60 Virginia Agricultural BMP Cost Share and Tax Credit Programs AWM, DWM, ESC, GM, NM Virginia Dept. Conservation and Recreation
61 Nutrient and Waste Management NM, AWM Univ. West Virginia
62 Comprehensive Livestock Environmental Assessments and Nutrient (CLEANEast) Management Plan program NM, AWM RTI International and North Carolina State Univ.

63 Comprehensive Nutrient Management Planning (CNMP) NM, AWM eXtension

64 CNMP Core Curriculum NM, AWM, ESC, GM Iowa State Univ.
65 Manure Management Planner Tutorials AWM, NM Univ. Missouri

Note:

a. 1 AWM=animal waste management, DWM=drainage water man agement, ESC=erosion and sediment control, GM=grazing management, NM=nutrient management2

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Chapter 2. Agriculture 2-168 

### I. Software and Models 1
1. Nutrient Management Planning Software for Profes sionals (NuMan Pro)—Univ. 2 Maryland Extension 3 Nutrient Management for Maryland Professional Editi on (NuMan Pro) is an integrated software 4 program that permits comprehensive nutrient managem ent planning. The Maryland Phosphorus 5 Site Index (PSI) has been integrated into the progr am so that warnings are given when a 6 PSI phosphorus site index calculation may be required based on soil test res ults. A simplified 7 version of the Revised Universal Soil Loss Equation (RUSLE) model to predict soil erosion 8 losses has been included in the program in support of the Maryland PSI assessment. Values for 9 rainfall erosivity (R) and soil erodibility (K) fac tors are determined from field location and soils 10 information entered in the initial portions of the program. Soil slope/steepness (LS), cropping 11 management (C), and conservation management (P) fac tors are determined from simplified user 12 inputs. Part A and Part B of the Maryland PSI are p resented in a color-code scheme for user ease. 13 Once slopes have been identified in the field, it i s estimated that an experienced user can 14 determine the Maryland PSI in less than 10 minutes. 15

Link: http://anmp.umd.edu/numan/numanpro.htm Accessed Retrieved January 28, 2010 16
2. AFOPro—Earth Sciences and Research Institute, Un iversity of South Carolina 17
AFOPro TM is a standalone nutrient management planning tool with optional connections to GIS 18 (ArcMap© and ArcView©) and the NRCS’s Animal Waste Management (v 2.0.2 or higher) 19 engineering software. The application allows the us er to plan manure and commercial fertilizer 20 allocation decisions in compliance with the NRCS’s 590 Standard, which requires the 21 documentation of form, source, timing, method, and placement of nutrients. The design of the 22 application is open, transparent, and flexible whic h enables it to be adapted to specific state crop 23 removals, nutrient risk ratings, and N nitrogen accounting requirements. Additionally, the 24 application uses modular Phosphorus Indices, state- specific fertility recommendations and state25 specific CNMP templates. 26

Link: http://www.esri.sc.edu/Projects/usda/application_de velopment/afopro.asp 27 Accessed Retrieved January 28, 2010 28
3. Animal Waste Management Software—USDA-NRCS 29 AWM 2.4.0, like the previous version, is a planning /design tool for animal feeding operations 30 that can be used to estimate the production of manu re, bedding, and process water and determine 31 the size of storage/treatment facilities. The proce dures and calculations used in AWM are based 32 on the USDA-NRCS Agricultural Waste Management Fiel d Handbook. 33
The AWM has been upgraded with the capability to ev aluate existing facilities. The results from 34 the evaluation are incorporated into the design pro cesses for new facilities. The user can design 35 the new facility either for the Additional waste not handled by the existing facility, or for the 36 Total waste flowing into the structure. 37
The evaluation process involves the user entering t he basic dimensions of an existing storage 38 facility along with other parameters such as herd s ize, local climatic condition (monthly rainfall), 39 and details about the additions such as bedding, wa sh water and flush water. With these inputs 402

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Chapter 2. Agriculture 2-169 the system estimates the total waste flowing into t he structure identified in the management train 1 for the selected storage period and compares it the available storage volume. It then presents an 2 on-screen color coded report (red for inadequate an d the green for the adequate structure.) This 3 report helps recognize if the structure is adequate ly designed or not easily and quickly. The user 4 can also print a hardcopy of this report. 5 The AWM process of evaluating existing structures c an help producers in deciding if they would 6 like to go for the No Discharge declaration within the EPA 2008 CAFO rule. The fac ility design 7 for the Total waste or for the Additional waste not handled by the existing structure is easily 8 done by selecting the appropriate radio button on t he AWM design screen. In addition, several 9 improvements and bug fixes, listed below, have been incorporated to further improve AWM 10 functions and capabilities. 11

Link: http://www.wsi.nrcs.usda.gov/products/W2Q/AWM/pgrm2 4.html Accessed Retrieve d 12 January 22, 2010 13
4. Manure Management Planner (MMP) Software

— - Purdue University 14 Manure Management Planner (MMP) is a Windows-based computer program developed at 15 Purdue University that is used to create manure man agement plans for crop and animal feeding 16 operations. The user enters information about the operation’s operation's fields, crops, storage, 17 animals, and application equipment. MMP helps the u ser allocate manure (where, when and how 18 much) on a monthly basis for the length of the plan (1-10 years). This allocation process helps 19 determine if the current operation has sufficient c rop acreage, seasonal land availability, manure 20 storage capacity, and application equipment to mana ge the manure produced in an 21 environmentally responsible manner. MMP is also use ful for identifying changes that may be 22 needed for a non-sustainable operation to become su stainable, and determine what changes may 23 be needed to keep an operation sustainable if the o peration expands. 24
MMP currently supports 34 states including DE, MD, and PA (support for VA is underway), by 25 automatically generating fertilizer recommendations and estimating manure N availability based 26 on each state’s state's Extension and/or NRCS guidelines. It should be not ed, however, that MMP 27 is not generally used in Maryland. Questions about MMP can be addressed to the authors using 28 contact information provided at the website. 29

Link: http://www.agry.purdue.edu/mmp/ Accessed Retrieved January 22, 2010 30
5. National Nutrient Management Data Download—Univ. of Missouri Extension 31 The data download website helps to address nutrient management software data requirements by 32 providing a way for users to locate the farm of int erest, define an area of interest and submit a 33 data request. 34

• The Spatial Nutrient Management Planner (SNMP) requ ires geo-referenced aerial 35 photographs, data from the soils survey, a topograp hic map and state-specific data on 36 manure application setback requirements. 37

• Manure Management Planner (MMP) needs data from the soils survey and crop and 38 climatology data from Natural Resource Conservation Service (NRCS). 392

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Chapter 2. Agriculture 2-170 • The data download also includes data needed by the Revised Soil Loss Equation version 1 2 (RUSLE(2)). 2
The data-finder packages the data in a compressed f ile that can be downloaded onto a computer 3 hard drive. The file is then un-compressed in the s ame folder on the computer the holds the 4 working SNMP and MMP files for that farm. This tool will generate a ZIP file containing the 5 aerial photo image, topographic map image, and soil s data needed for SNMP, MMP and 6 RUSLE(2). The data is obtained from various USDA-NR CS data servers for any area with 7 spatial data

in the NRCS Soils Data Mart (see Status Map ). Google Maps is used to locate farms 8 and define a download area which includes the farm. 9

Link: http://www.nmplanner.missouri.edu/software/national _data.asp Accessed Retrieved 10 January 22, 2010 11
6. Spatial Nutrient Management Planner—Univ. of Mis souri Extension 12 The Spatial Nutrient Management Planner (SNMP) is a decision support tool that facilitates the 13 collection, analysis and presentation of spatial da ta related to nutrient management planning. 14 Capabilities of SNMP include: 15

• The SNMP interface simplifies the GIS program ArcMa p for nutrient management 16 planners. 17

• With a click of a mouse, data can be imported and e xported from Purdue’s Purdue's 18 Manure Management Planner (MMP)

. 19

• SNMP simplifies the creation of maps required for N RCS comprehensive nutrient 20 management plans 21

• Compatibility with NRCS Toolkit 9.x. 22

Link: http://projects.cares.missouri.edu/snmp/nrcsdata/ao ilist.asp Accessed Retrieved January 22, 23 2010 24
7. Win Max—Purdue University 25 WinMax is a computer program developed at Purdue University to calculate and compare 26 economic returns on crop production. WinMax manages crop input data, calculates crop fertilizer 27 recommendations, generates production cost and nutr ient management worksheets, and allows 28 sets of custom input costs to be created and used i n all calculations. WinMax supports the import 29 of data from a manure management plan created with MMP, as well as the export of WinMax 30 data to an MMP plan. Various management options, su ch as tillage, pest control and fertilizer 31 strategies, can be compared to help assess which pr actices are both economically efficient and 32 environmentally sound. 33

Link: http://www.agry.purdue.edu/max/ Accessed Retrieved January 22, 2010 34
8. MapWindow GIS + MMP Tools—Purdue University 35 MapWindow GIS + MMP Tools is a free GIS that can be used as a front-end to MMP and 36 WinMax. 372

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Chapter 2. Agriculture 2-171 Link: http://www.agry.purdue.edu/mmp/mapwindow/ Accessed Retrieved January 22, 2010 1
9. Manure Master Decision Support System—USDA-NRCS 2 This simple screening tool can help assess the rela tive potential for the nutrients contained in the 3 animal manure on a farm to meet the crop uptake and use requirements for those crops that 4 receive applications of manure. Manure Master is an on-farm manure balance tool. It allows 5 users to compare the nutrient content in the animal manure produced on the farm with the 6 quantity of nutrients used and removed from the fie ld on which manure is applied. 7

Manure Master calculates a balance between the N, P nitrogen, phosphorus , and potassium 8 content in the manure and the quantity of these nut rients used by crops. This balance can be 9 calculated based upon recommended fertilizer applic ation rates, when known or upon estimated 10 plant nutrient content, when recommended fertilizer application rates are not known. For 11 N nitrogen , the balance is calculated taking into account exp ected losses from leaching, 12 denitrification, and volatilization. 13
Manure Master produces a report that includes the b alance for N, P nitrogen, phosphorus , and 14 potassium for these fields. The balance will advise producers of whether the quantity of nutrients 15 in the animal manure exceeds the quantity removed i n harvested plants or the quantity of 16 nutrients recommended. 17

Link: http://www2.ftw.nrcs.usda.gov/mm/ Accessed Retrieved January 22, 2010 18
10. Revised Universal Soil Loss Equation, Version 2 (RUSLE2)—USDA-NRCS 19
This site contains the official NRCS version of RUS LE2. It is the only version of RUSLE2 to be 20 used for official purposes by NRCS field offices. T he NRCS developed and maintains the 21 database components on this site. 22
RUSLE2 is an upgrade of the text-based RUSLE DOS ve rsion 1. It is a computer model 23 containing both empirical and process-based science in a Windows environment that predicts rill 24 and interrill erosion by rainfall and runoff. The U SDA-Agricultural Research Service (ARS) is 25 the lead agency for developing the RUSLE2 model. Th e ARS, through university and private 26 contractors, is responsible for developing the scie nce in the model and the model interface. 27

Link: http://fargo.nserl.purdue.edu/rusle2_dataweb/RUSLE2 _Index.htm Accessed Retrieved 28 January 22, 2010 29
11. Using RUSLE2 for the Design and Predicted Effec tiveness of Vegetative Filter Strips 30 (VFS) for Sediment—USDA-NRCS 31 The Revised Universal Soil Loss Equation, Version 2 , (RUSLE2) can also be used to design and 32 predict the expected lifespan of a VFS designed for the purpose of sediment removal based on 33 the procedures developed by Dillaha and Hayes. The following information is needed: 34

• Sediment delivery rate at the upper edge of the VFS for the contributing area to the 35 VFS—calculated by RUSLE2 using the overland flow slope length

. 36

• Sediment Trapping Efficiency—calculated from RUSLE2 results. 37

• Ratio of Contributing Area to VFS Area. 382

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Chapter 2. Agriculture 2-172 This publication requires Microsoft Excel and uses the following spreadsheet: 1 Filter Strip Life Span Design for Sediment (XLS; 24 KB) 2

Link: http://directives.sc.egov.usda.gov/OpenNonWebConten t.aspx?content=18578.wba 3 Accessed Retrieved January 22, 2010 4
Additional Reference: USDA-NRCS. 2007. Agronomy Tec hnical Note No. 2, Using RUSLE2 5 for the Design and Predicted Effectiveness of Veget ative Filter Strips (VFS) for Sediment, 8pp. 6
12. Vegetative Filter Strip Modeling System (VFSMOD )—University of Florida 7 VFSMOD-W is a design-oriented vegetative filter str ip modeling system. The MS-Windows 8 graphical user interface (GUI) integrates the numer ical model VFSMOD, a utility to generate 9 source (upslope disturbed area) inputs for the mode l based on readily available NRCS site 10 characteristics (UH), and advanced uncertainty and sensitivity analysis, inverse calibration and 11 design menu-driven components. VFSMOD, the core of the modeling system, is a computer 12 simulation model created to study hydrology, sedime nt and pollutant transport through 13 vegetative filter strips (VFS). The model is target ed at studying VFS performance on an event14 by-event basis and when combined with the upslope s ource area input preparation utility (UH or 15 others like PRZM), becomes a powerful and objective VFS design tool. The design paradigm 16 implemented in VFSMOD-W seeks to identify optimal f ilter constructive characteristics (length, 17 slope, vegetation) to reduce (to a prescribed reduc tion target like a TMDL) the outflow of 18 pollutants from a given disturbed area (soil, crop, area, management practices, design storm 19 return period). 20
VFSMOD has been tested in a variety of settings (ag roforestry, mining and roads) with good 21 model predictions against measured values of infilt ration, outflow, and vegetation trapping 22 efficiency for sediments, P phosphorus , and pesticides. Although the model was originally 23 developed as research tool, is now widely used by c onsultants, planners and regulators to design 24 optimal filter strips for specific scenarios or to assess effectiveness of existing VFS. 25

Link: http://carpena.ifas.ufl.edu/vfsmod/ Accessed Retrieved January 28, 2010 26
13. Integrated Farm System Model (IFSM)—USDA-ARS 27 The Integrated Farm System Model (IFSM) is a proces s-based simulation of dairy, beef, and 28 crop farming systems. This farm model provides a to ol for evaluating the long-term 29 performance, economics, and environmental impacts o f production systems over many years of 30 weather. Environmental impacts include volatile N nitrogen losses, nitrate loss to ground water, 31 erosion, soluble and sediment P phosphorus losses to surface water, and greenhouse gas 32 emissions. 33

Link: http://www.ars.usda.gov/Main/docs.htm?docid=8519 Accessed Retrieved January 27, 2010 34
14. Dairy Greenhouse Gas Model (DairyGHG)—USDA-ARS 35 The Dairy Greenhouse Gas Model (DairyGHG) is an eas y to use software tool that estimates 36 total greenhouse gas emissions and the carbon footp rint of a dairy production system. DairyGHG 37 uses a relatively simple process-based model to pre dict the primary GHG emissions from the 38 production system, which include the net emission o f carbon dioxide plus all emissions of 392

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Chapter 2. Agriculture 2-173 methane and nitrous oxide. Emissions are predicted through a daily simulation of feed use and 1 manure handling where daily values of each gas are summed to obtain annual values. A carbon 2 footprint is then calculated as the sum of both pri mary and secondary emissions in CO2 3 equivalent units divided by the milk produced. Seco ndary emissions are those occurring during 4 the production of resources used including machiner y, fuel, electricity, fertilizer, pesticides, and 5 plastic. DairyGHG is available for download from ou r Internet site 6 ( http://ars.usda.gov/naa/pswmru). http://ars.usda.gov/naa/p swmru). The model includes a fully 7 integrated help system with a reference manual that documents the relationships used to predict 8 emissions. 9

Link: http://www.ars.usda.gov/Main/docs.htm?docid=17355 Accessed Retrieved January 27, 10 2010 11
15. Cropware—Cornell University Extension 12 Cropware is used to develop plans in accordance wit h the NRCS Nutrient Management Standard 13 (Standard 590), making the output of Cropware a key component of Comprehensive Nutrient 14 Management Plans. Cornell Cropware integrates the f ollowing tools for effective nutrient 15 management planning: 16

• Cornell crop nutrient guidelines for a full range o f agronomic and vegetable crops. 17

• Nutrient credits from many sources, including manur e, soil, sod, and fertilizer. 18

• Equations for the conversion of soil test values fr om other laboratories into Cornell 19 Morgan equivalents. 20

• Environmental risk indices, including the New York State Phosphorus Runoff Index and 21 the Nitrate Leaching Index. 22

• On-farm logistics, such as manure production, stora ge, and inventories Report generation 23 for guiding on-farm implementation. 24

Link: http://nmsp.cals.cornell.edu/software/cropware.html Accessed Retrieved January 27, 2010 25
16. Soil Test Conversion Tools—Cornell University E xtension 26 This program converts soil test results from Brooks ide Laboratories Inc. (Mehlich-3 P, K, Ca, 27 Mg), Spectrum Analytic Inc. (Mehlich-3 P, K, Ca, an d Mg and Morgan P, K, Ca, and Mg), A&L 28 Laboratories Inc. (Mehlich-3 P, K, Ca, Mg and Modif ied Morgan P), and the soil testing 29 laboratories from the University of New Hampshire ( Mehlich-3 P, K, Ca and Mg), University of 30 Massachusetts (Morgan P, K, Ca, and Mg) and the Uni versities of Vermont and Maine 31 (Modified Morgan P, K, Ca, Mg) to Cornell Universit y Morgan Equivalents. P Phosphorus 32 conversions from Mehlich-3 data require measured va lues for soil pH, Mehlich-3 P, Ca, and Al. 33 For each test, the range of valid input data is giv en by a minimum value (min) and a maximum 34 value (max). Also given are the correlation coeffic ients (r 2 ) for each of the conversion models. 35 Conversions with larger r 2 values are more reliable. Models were derived usin g New York soils. 36 There is uncertainty involved with each of the conv ersions and we now know there is seasonality 37 in the conversions with the most reliable conversio ns obtained when samples are taken after 38 harvest and before manure application. The user ass umes all risk and it is recommended to 39 submit samples for the Cornell Morgan test to check on the accuracy of the conversion models 402

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Chapter 2. Agriculture 2-174 for your farm or the farm you work with. It is also recommended to take 3 subsamples per acre if 1 you use conversion models to derive Cornell Morgan soil test equivalents. 2

Link: http://nmsp.cals.cornell.edu/software/conv-tools.ht ml Accessed Retrieved January 27, 2010 3
17. Great Plains Framework for Agricultural Resourc e Management (GPFARM)—USDA4 ARS 5 Great Plains Framework for Agricultural Resource Ma nagement (GPFARM) is a simulation 6 model computer application that incorporates state- of-the-art knowledge of agronomy, animal 7 science, economics, weed science, and risk manageme nt into a user-friendly, decision-support 8 tool. Producers and others can use GPFARM to test a lternative management strategies with 9 regard to sustainability, pollution reduction, and economic return. 10

Link: http://www.ars.usda.gov/services/software/download. htm?softwareid=234 11 Accessed Retrieved January 27, 2010 12

18. S oil - P lant - A tmosphere—W ater Field & Pond Hydrology (SPAW)—USDA-ARS 13 SPAW is a daily hydrologic budget model for agricul tural fields and ponds (wetlands, lagoons, 14 ponds and reservoirs). Included are irrigation sche duling and soil N. nitrogen. Companion models 15 for soil water characteristics and chemical budgets are included. Data input and results are 16 graphical screens. 17

Link: http://hydrolab.arsusda.gov/SPAW/Index.htm Accessed Retrieved January 28, 2010 18



### II. Calculators, Spreadsheets, and Graphical Tools 19
19. Dairy Cattle N Excretion Calculator—Cornell Uni versity Extension 20 The Dairy Cattle N Excretion Calculator enables use rs to quickly characterize rations, individual 21 dairy cattle, and groups of dairy cattle to predict the N partitioned to growth, milk production, 22 pregnancy, urine, and feces. From there, N use effi ciency and N volatilization from the barn 23 floor are estimated. 24

Link: http://www.dairyn.cornell.edu/pages/40dairy/420prec ision/424herdspread.shtml 25 Accessed Retrieved January 27, 2010 26
20. Corn N Calculator—Cornell University Extension 27 This calculator factors in soil type, drainage, and other factors to estimate corn N requirements. 28

Link: http://www.dairyn.cornell.edu/pages/20cropsoil/240g uides/245corn.shtml 29 Accessed Retrieved January 27, 2010 30
21. Total N Available from Manure Applications—Corn ell University Extension 31
N Nitrogen from urine (ammonium N) is quickly available for c rop uptake, while N from feces 32 (organic N) is more slowly released. Manure represe nts a mix of both urine and feces, so 33 estimations of the amount of plant available N from manure should be based on both. 342

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Chapter 2. Agriculture 2-175 The total manure N calculator uses factors such as animal type, percent dry matter, organic N 1 content, and application rate to estimate the combi ned contributions of organic N and ammonium 2 N to the total pool of plant available N from manur e. 3

Link: http://www.dairyn.cornell.edu/pages/20cropsoil/250c redits/256totalN.shtml 4 Accessed Retrieved January 27, 2010 5
22. Other Calculators—Cornell University Extension 6 This page provides links to calculators for corn N needs, manure nutrients, N credits from 7 plowed sods, and whole-farm nutrient balancing. 8

Link: http://nmsp.cals.cornell.edu/software/calculators.h tml Accessed Retrieved January 27, 2010 9
23. Nutrient Management Spreadsheets—University of Delaware Cooperative Extension 10 This page includes links to two spreadsheets, one f or estimating animal waste quantity, and the 11 other for estimating poultry litter quantity. 12

Link: http://ag.udel.edu/extension/NutriManage/spreadshee ts.htm Accessed Retrieved January 13 27, 2010 14
24. Crop Nutrient Tool—USDA-NRCS 15 This is a tool for calculating the approximate amou nt of N, P nitrogen, phosphorus , and 16 potassium that is removed by the harvest of agricul tural crops. 17

Link: http://plants.usda.gov/npk/main Accessed Retrieved January 22, 2010 18
25. Crop Fertilizer Recommendation Calculator—Purdu e University 19 This calculator is currently supported for DE, MD, and PA. 20

Link: http://www.agry.purdue.edu/mmp/webcalc/fertRec.asp Accessed Retrieved January 22, 21 2010 22
26. Manure Nutrient Availability Calculator—Purdue University 23 This calculator is currently supported for DE, MD, and PA. 24

Link: http://www.agry.purdue.edu/mmp/webcalc/nutAvail.asp Accessed Retrieved January 22, 25 2010 26
27. Conservation Buffers—USDA National Agroforestry Center 27 At any given site, the level of pollutant removal f rom surface runoff depends primarily on buffer 28 width. The graph and tables at this site can be use d to estimate a buffer width that will achieve a 29 desired level of pollutant removal. The tool is des igned to quickly generate estimates of design 30 width for a broad range of site conditions. Adjustm ents are made for land slope, soil texture, 31 field size, and soil surface condition. The tool ca n be used for sediment, sediment-bound 32 pollutants, and dissolved pollutants. The tool was developed for agricultural runoff using 332

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Chapter 2. Agriculture 2-176 VSFMOD (Vegetative Filter Strip Model), but can be applied in a more general way to other 1 land uses as well. 2

Link: http://www.unl.edu/nac/bufferguidelines/guidelines/ 1_water_quality/19.html 3 Accessed Retrieved January 26, 2010 4
28. Farm*A*Syst—University of Wisconsin Extension 5 Farm*A*Syst is a partnership between government age ncies and private business that enables 6 landowners to prevent pollution on farms, ranches, and in homes using confidential 7 environmental assessments. A system of step-by-step factsheets and worksheets helps 8 landowners identify the behaviors and practices tha t create risks associated with livestock waste 9 storage, nutrient management, wells, hazardous wast es, and petroleum products. 10

Link: http://www.uwex.edu/farmasyst/ Accessed Retrieved January 27, 2010 11



### III. Compilations of Tools 12
29. Technical Resources Main Page—USDA-NRCS 13 This page serves as the gateway to a wide range of technical resources provided by USDA. 14

Link: http://www.nrcs.usda.gov/technical/ 15
30. Animal Feeding Operations (AFO) Virtual Informa tion Center - USEPA 16
The AFO Virtual Information Center is a tool to fac ilitate quick access to livestock agricultural 17 information in the US. This site is a single point of reference to obtain links to state regulations, 18 web sites, permits and policies, nutrient management information , livestock and trade 19 associations, federal web sites, best management pr actices and controls, cooperative extension 20 and land grant universities, research, funding, and information on environmental issues. The 21 nutrient management information page has links to n utrient management resources for Delaware, 22 Maryland, Pennsylvania, Virginia, and West Virginia

. 23

Link: http://cfpub.epa.gov/npdes/afo/virtualcenter.cfm Accessed Retrieved January 28, 2010 24

31. Software Products—USDA-ARS 25 This page provides updated information on software tools available from USDA-ARS. 26 Additional information on ARS models and projects c an be found here

. 27

Link: http://www.ars.usda.gov/Services/software/software. htm Accessed Retri eved January 27, 28 2010 29
32. Nutrient Management Planning Software and Suppo rt—Univ. of Missouri Extension 30 This page provides links to national resources that facilitate writing a nutrient management plan. 31 The listed resources contribute to a unified system for writing a nutrient management plan that 32 meets national standards for NRCS and USEPA. 332

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Chapter 2. Agriculture 2-177 a. Nutrient Management Data Download : Use the Nutrient Management Data Finder to 1 obtain data needed by nutrient management software to complete a plan. 2

b. Spatial Nutrient Management Planner (SNMP) : Use the SNMP to collect and analyze 3 spatial information and create maps needed for comp leting a nutrient management plan. 4

c. Purdue’s Manure Management Planner (MMP) : Use MMP to determine fertilizer and 5 manure application rates and generate the nutrient management plan. 6

d. Manure Management Planner (MMP) Tutorials : Tutorials on how to use MMP to develop 7 a swine, poultry or fertilizer only plan. 8

e. National Setbacks Database : Access a database on the web that reports setback 9 requirements for the 34 states supported by SNMP an d MMP. 10

Link: http://www.nmplanner.missouri.edu/software/ Accessed Retrieved January 22, 2010 11



### IV. Guidance and Other Technical Resources 12
33. Nutrient and Pest Management Tools and Informat ion - USDA-NRCS 13 Users will find fact sheets on practices and links to various tools for nutrient and pest 14 management at this site. 15

Link: http://www.nrcs.usda.gov/technical/nutrient.html Accessed Retrieved January 26, 2010 16

34. Conservation Practices—USDA-NRCS 17
At this site users will find links to the Field Off ice Technical Guide and the National Handbook 18 of Conservation Practices. Links to each state’s el ectronic Field Office Technical Guide 19 (eFOTG) can be found here

. 20

Link: http://www.nrcs.usda.gov/technical/standards/ Accessed Retrieved January 26, 2010 21
35. Agronomy and Erosion—USDA-NRCS 22 This site has links to the National Agronomy Manual , a publication on using RUSLE2 to design 23 and predict the effectiveness of vegetative filter strips for sediment control, Core 4 Conservation, 24 and other resources. 25
http://www.nrcs.usda.gov/technical/agronomy.html Accessed Retrieved January 27, 2010 26
36. Animal Feeding Operations—USDA-NRCS 27 This page provides information on CNMPs and links t o the MMP and the CNMP field 28 handbook. 29

Link: http://www.nrcs.usda.gov/technical/afo/index.html Accessed Retrieved January 27, 2010 302

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Chapter 2. Agriculture 2-178 37. Nutrient Management Technical Notes—USDA-NRCS 1 This page includes links to several fact sheets on diet and feed management for various types of 2 livestock. The page also includes links for Nationa l Conservation Practice Standards for nutrient 3 management ( NRCS Practice Code 590) and waste utilization ( NRCS Practice Code 633). 4

Link: http://www.nrcs.usda.gov/technical/ECS/nutrient/doc uments.html Accessed Retrieved 5 January 22, 2010 6
38. National Range and Pasture Handbook—USDA-NRCS 7 This handbook includes chapters on grazing manageme nt and conservation planning for grazing 8 lands. 9

Link: http://www.glti.nrcs.usda.gov/technical/publication s/nrph.html Accessed Retrieved January 10 27, 2010 11
39. Phosphorus Index—USDA-NRCS 12 This page provides background on the Phosphorus Ind ex, which is intended to provide field 13 staffs, watershed planners, and land users with a t ool to assess the various landforms and 14 management practices for potential risk of P phosphorus movement to water bodies. 15
USDA is careful to point out that 16
the phosphorus index is not intended to be an evalu ation scale for determining whether 17 land users are abiding within water quality or nutrient management standards that have 18 been established by local, state, or federal agenci es. Any attempt to use this index as a 19 regulatory scale would be grossly beyond the intent of the assessment tool and the 20 concept and philosophy of the working group that de veloped it. The Phosphorus Index is 21 proposed to be adapted to local conditions by a pro cess of regional adaptations of the site 22 characteristic parameters. This local development p rocess must involve those local and 23 state agencies and resource groups that are concern ed with the management of 24 phosphorus. After the index is adapted to a localit y, it must be tested by the development 25 group to assure that the assessments are giving val id and reasonable results for that 26 region. Field testing of the index is one of the mo st appropriate methods for assessing the 27 value of the index. 28

Link: http://www.nrcs.usda.gov/technical/ecs/nutrient/pin dex.html Accessed Retrieved January 29 29, 2010 30

40. SERA-17 Publications and BMP Fact Sheets 31
SERA-17 is an organization of research scientists, policy m akers, extension personnel, and 32 educators whose mission is to develop and promote i nnovative solutions to minimize phosphorus 33 losses from agriculture by supporting : 34

• Information information exchange between research, extension, and regulato ry 35 communities 36

• Recommendations recommendations for phosphorus management and research 372

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Chapter 2. Agriculture 2-179 • Initiatives initiatives that address phosphorus loss in agriculture 1

Link: http://www.sera17.ext.vt.edu/SERA_17_Publications.h tm Accessed Retrieved January 22, 2 2010 3
41. Managing Cover Crops Profitably, 3 rd Edition—SARE 4 This 2007 update from Sustainable Agriculture Resea rch and Education (SARE) includes 5 information on the benefits of cover crops, selecti ng cover crops, the use of cover crops with 6 conservation tillage, crop rotations, and a wide ra nge of legume and non-legume cover crops. 7 Appendix E contains contact information for regiona l cover crop experts 8

Link: http://www.sare.org/publications/covercrops/index.s html Accessed Retrieved January 27, 9 2010 10
42. Precision Feed Management Certification for Dai ry Professionals—Mid-Atlantic Water 11 Program 12
To In order to help reduce nutrient pollution and implement the NR CS Feed Management 13 Standard 592, specialists in Pennsylvania, Maryland and Virginia are working with NRCS and 14 the American Registry of Professional Animal Scient ists to develop a process to certify 15 nutritionists as feed management planners. With few areas in the nation working with the dairy 16 industry and NRCS on feed management, the Mid-Atlan tic is being looked at as a potential 17 standard for how other states can train nutritionis ts for a feed management certification and meet 18 their post-certification, professional needs. This page provides current information on precision 19 feed management certification, including contact in formation for leaders from MD, PA, and VA. 20

Link: http://mawaterquality.org/industry_change/precision _feed_mgmt.html Accessed Retrieved 21 January 27, 2010 22
43. Mid-Atlantic Better Composting School—Mid-Atlan tic Water Program 23 Since commercial compost can be manufactured from a variety of waste materials, a variety of 24 standards have been established based on end-uses. Managers of composting facilities 25 should must be familiar with these standards and with the wast e materials and composting 26 systems that can best produce the desired products. Composting to produce a product that is 27 consistent in quality will require good management and quality control. 28
By enrolling in the Mid-Atlantic Better Composing S chool, participants will not only learn the 29 basics of making good compost, but they will also h ave the opportunity to tour commercial 30 operations, perform product sampling and learn simp le procedures for compost testing. 31

Link: http://mawaterquality.org/industry_change/ma_compos ting_school.html 32 Accessed Retrieved January 27, 2010 33
44. Environmental Management System for Manure—Mid- Atlantic Water Program 34 Members from the Mid-Atlantic Water Program (MAWP) are collaborating with CLEANeast to 35 assess livestock and poultry operations in sensitiv e watersheds across PA, MD, and VA using an 36 Environmental Management Systems (EMS) model. An EM S is a voluntary, flexible business 372

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Chapter 2. Agriculture 2-180 management system that helps farmers and managers t o develop their own strategies for 1 integrating environmental considerations into the d aily operations of a farm. 2
By implementing pilot assessments across farms in P A, VA, and MD, team members will 3 demonstrate how an EMS can not only reduce pollutio n from farms, but also increase operating 4 efficiency, achieve public acceptance without regul atory oversight, and elicit confidence in 5 citizens that the wastes are being handled in an en vironmentally sound manner. 6
This page also provides state contacts information. 7

Link: http://mawaterquality.org/industry_change/env_mgmt_ system_manure.html 8 Accessed Retrieved January 27, 2010 9
45. Mid-Atlantic Nutrient Management Handbook—Mid-A tlantic Water Program 10 The Mid-Atlantic Nutrient Management Handbook was w ritten as a reference text for nutrient 11 management training programs offered by state regul atory agencies. The Handbook was based 12 off an earlier nutrient management training manual that was widely used in the Chesapeake Bay 13 watershed, but revised to incorporate advances in s oil, crop, and nutrient management research 14 and the techniques used to protect surface and grou ndwater. 15

Link: http://mawaterquality.org/capacity_building/ma_nutr ient_mgmt_handbook.html 16 Accessed Retrieved January 27, 2010 17
46. Information on Nutrient and Sediment Best Manag ement Practices—Chesapeake Bay 18 Program 19 This report led by the University of Maryland Mid-A tlantic Water Program includes nutrient and 20 sediment reduction effectiveness estimates of selec t agricultural, stormwater and forestry best 21 management practices (BMPs). With funding from the Chesapeake Bay Program Office, the 22 Mid-Atlantic Water Program developed definitions an d effectiveness estimates for BMPs that 23 states were implementing or proposing to implement as part of their efforts to meet the nutrient 24 and sediment reduction goals necessary to restore t he Bay. The report provides realistic, science25 based estimates of expected nutrient and sediment r eduction performance from these BMPs and 26 reflects current research and knowledge as well as average operational conditions representative 27 of the entire Chesapeake Bay Watershed. 28

Link: http://www.chesapeakebay.net/marylandbmp.aspx?menui tem=34449 Accessed Retrieved 29 January 27, 2010 30
47. Fact Sheets—University of Delaware Cooperative Extension 31 This page contains links to several fact sheets on nutrient management, poultry litter 32 management, and animal waste management. 33

Link: http://ag.udel.edu/extension/NutriManage/publicatio ns.htm Accessed Retrieved January 27, 34 2010 352

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Chapter 2. Agriculture 2-181 48. Nutrient Management—Maryland Department of L., J. A. Nienaber, et al. (2003). 1 Performance of a passive feedlot runoff control and treatment system. Transactions of the 2 ASAE Asae 46(6): 1525

– - 1530. 3 Ladha, J.K., Pathak, H., Krupnik, T.J., Six, J. and van Kessel, C. 2005. Efficiency of fertilizer 4 nitrogen in cereal production: retrospects and pros pects. Advances in Agronomy 87:85-156. 5 Mosier, A.R., J.K. Syers, and J.R. Freney. 2004. Ch . 1-Nitrogen fertilizer: an essential 6 component of increased food, feed, and fiber produc tion. pp. 3-15. In A.R. Mosier, J.K. 7 Syers, and J.R. Freney (eds.). Agriculture and the Nitrogen Cycle. Assessing the impacts 8
This page provides various links to nutrient manage ment fact sheets, recommendations, and 9 training opportunities. 10

Link: http://www.mda.state.md.us/resource_conservation/nu trient_management/index.php 11 Accessed Retrieved January 27, 2010 12
49. Nutrient Management Program—University of Maryl and Extension 13 The Agricultural Nutrient Management Program is a c omponent of the University of 14 Maryland’s Maryland's College of Agriculture and Natural Resources Nutri ent Management 15 Programs and focuses on reducing the pollution of t he Chesapeake Bay by plant nutrients from 16 cropland. The Program provides nutrient planning se rvices to Maryland farmers via a network of 17 nutrient management advisors located in all county Extension offices and provides continuing 18 education and technical support to certified nutrie nt management consultants via state and 19 regional nutrient management specialists. 20
One of these services is the development of nutrien t management plans, which are documents 21 that incorporate soil test results, yield goals, an d estimates of residual N nitrogen to generate 22 field-by-field nutrient recommendations. 23

Link: http://anmp.umd.edu/ Accessed Retrieved January 27, 2010 24
50. Nutrient Management Plan Writing Tools—Universi ty of Maryland Extension 25 A nutrient management plan is a formal document tha t balances crop nutrient needs with 26 nutrients that are applied in the form of commercia l fertilizer, animal manure, or biosolids. The 27 plan contains soil test results, manure and biosoli ds analyses (where applicable), yield goals, and 28 estimates of residual N nitrogen to generate field-by-field nutrient recommendation s. The 29 following information sheets and work sheets will h elp producers in the plan writing process

. 30

Link: http://anmp.umd.edu/Plan/Plan_Writing.html Accessed Retrieved January 27, 2010 31
51. Phosphorus Site Index—University of Maryland Ex tension 32 The Phosphorus Site Index, or PSI, is an integral p art of a nutrient management plan. If a 33 producer intends to add P phosphorus in commercial or organic forms (including starter fertilizer) 34 to a field and the soil test indicates a P phosphorus fertility index value (FIV-P) of 150 or more 35 for that particular field, then the PSI should be c alculated. The PSI takes into consideration 36 P phosphorus loss potential due to site and transport character istics and management and source 37 characteristics. 382

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Chapter 2. Agriculture 2-182 Link: http://anmp.umd.edu/PSI/PSI.html Accessed Retrieved January 27, 2010 1
52. Nutrient Management Software and Publications—U niversity of Maryland Extension 2 This page provides summary information and links to available publications and software for 3 nutrient management in Maryland. 4

Link: http://anmp.umd.edu/Pubs/Pubs.html Accessed Retrieved January 27, 2010 5
53. Nutrient Management Spear Program—Cornell Unive rsity 6
The vision of the Cornell University’s University's Nutrient Management Spear Program is to 7 assess current knowledge, identify research and edu cational needs, conduct applied, field and 8 laboratory-based research, facilitate technology an d knowledge transfer, and aid in the on-farm 9 implementation of strategies for field crop nutrien t management, including timely application of 10 organic and inorganic nutrient sources to improve p rofitability and competitiveness of New York 11 State farms while protecting the environment. 12
This page has links to a variety of nutrient manage ment resources, including nutrient guidelines, 13 N nitrogen management, and the New York State Phosphorus Runoff Index . These links provide 14 additional links to tools and resources such as Cro pware and other nutrient management 15 calculators. 16

Link: http://nmsp.cals.cornell.edu/index.html Accessed Ret rieved January 27, 2010 17
54. Manure Management—Penn State College of Agricul tural Sciences 18 This page provides information on manure management at animal operations, including links to 19 information specific to Pennsylvania. 20

Link: http://www.das.psu.edu/research-extension/nutrient- management/manure 21 Accessed Retrieved January 27, 2010 22
55. Pennsylvania Nutrient Management Program—Penn S tate University 23 This web site provides a comprehensive source of in formation about 24 Pennsylvania’s Pennsylvania's Nutrient Management Act (Act 38, 2005) Program, an d associated 25 technical guidance and educational information. It also provides limited information concerning 26 related programs. The web site has been developed a nd is maintained through a workgroup 27 representing various partnering agencies actively i nvolved with the Pennsylvania Nutrient 28 Management Act Program. Contributions to this site represent the collective efforts of that 29 workgroup 30

Link: http://panutrientmgmt.cas.psu.edu/ Accessed Retrieved January 27, 2010 31
56. Planning Tools and Resources—Penn State Univers ity 32 This page provides links to the nutrient management plan standard format, a nutrient balance 33 spreadsheet, the Pennsylvania Phosphorus Index spre adsheet, a pasture nutrient calculator, and 34 other resources associated with nutrient management in Pennsylvania. Contained within the 35 Phosphorus Index spreadsheet is contact information for state experts. 362

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Chapter 2. Agriculture 2-183 Link: http://panutrientmgmt.cas.psu.edu/main_planning_too ls.htm Accessed Retrieved January 1 27, 2010 2
57. Nutrient Management Technical Manual—Penn State University 3 This is the technical manual for Pennsylvania’s Nut rient Management Act Program. 4

Link: http://panutrientmgmt.cas.psu.edu/main_technical_ma nual.htm Accessed Retrieved January 5 27, 2010 6
58. Educational Materials—Penn State University 7 This page provides links to fact sheets and publica tions addressing of wide range of topics 8 associated with nutrient management and manure mana gement in Pennsylvania. 9

Link: http://panutrientmgmt.cas.psu.edu/em_publications.h tm Accessed Retrieved January 27, 10 2010 11
59. Fact Sheets on Agriculture and Environmental Qu ality—Virginia Tech Extension 12 The page provides links to fact sheets covering a r ange of topics including composting, 13 P phosphorus management, and livestock exclusion. 14

Link: http://pubs.ext.vt.edu/category/environmental-quali ty.html Accessed Retrieved January 27, 15 2010 16
60. Virginia Agricultural BMP Cost Share and Tax Cr edit Programs—Virginia 17 Department of Conservation and Recreation 18 This page provides information and links associated with agricultural BMPs in Virginia, 19 including the Virginia agricultural BMP manual and BMP cost-sharing. 20

Link: http://www.dcr.virginia.gov/soil_and_water/costshar .shtml Accessed Retrieved January 27, 21 2010 22
61. Nutrient and Waste Management—West Virginia Uni versity Extension Service 23 This page provides links to nutrient management tra ining courses including the P index, 24 information on nutrient management consultant certi fication, manure sampling and analysis 25 methods, and related websites. 26

Link: http://www.wvu.edu/~agexten/wastmang/index.html Accessed Retrieved January 28, 2010 27
62. Comprehensive Livestock Environmental Assessmen ts and Nutrient (CLEANEast) 28 Management Plan program—RTI International and North Carolina State University 29 CLEANEast provides confidential, free technical sup port to farms including beef, dairy, swine, 30 or poultry operations located in 27 eastern states. It helps farm operators identify and implement 31 farm management practices that protect the environm ent. CLEANEast is a voluntary program 32 that farm operators can apply to for on-site suppor t services from a qualified Technical 33 Assistance Professional to: 342

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Chapter 2. Agriculture 2-184 • Conduct an Environmental Assessment 1

• Update an existing Nutrient Management Plan 2

• Prepare a new Nutrient Management Plan 3

Link: https://livestock.rti.org/ Accessed Retrieved January 28, 2010 4
63. Comprehensive Nutrient Management Planning (CNM P) - eXtension 5 The details of a Comprehensive Nutrient Management Plan (CNMP) are described at this site, 6 including links to various handbooks and guidance d ocuments important to the development of a 7 CNMP for an animal feeding operation. For example, a key objective of a CNMP is to document 8 the plans of an animal feeding operation owner/oper ator to manage manure and organic by9 products in combination with conservation practices and facility management activities to protect 10 or improve water quality. NRCS has listed six eleme nts of a CNMP that should be considered 11 during preparation of the plan, though a CNMP is no t required to contain all six elements. The 12 components that should be considered are: 13

• Manure and Wastewater Storage and Handling 14

• Land Treatment Practices 15

• Nutrient Management 16

• Record Keeping 17

• Feed Management 18

• Other Utilization Activities 19
A complete description of these elements, and what each element specifically covers, is included 20 in the USDA-NRCS National Planning Procedures Handbook (Part 600.5). Users should check 21 with their agriculture and natural resources agenci es to see if their state has its own specific 22 CNMP requirements and guidance. 23

Link: 24 http://www.extension.org/pages/Comprehensive_Nutrie nt_Management_Planning_%28CNMP% 25 29 Accessed Retrieved January 22, 2010 26
64. CNMP Core Curriculum—Iowa State University 27
There are several sources for additional informatio n about CNMPs. Many land grant universities 28 and other commodity/producer organizations provide informational literature and websites. 29 Additionally, state NRCS offices often maintain CNM P/TSP informational web pages. A source 30 of information about CNMPs is the CNMP Core Curriculum training modules maintained by 31 Iowa State University and available through the Mid west Plan Service. The CNMP Core 32 Curriculum is also a good resource for educators in terested in providing training on CNMP 33 development. Also, the breadth of information cover ed in the topic areas make the curriculum a 34 good source of materials for smaller scale training s, such as shorter, topic specific extension 35 programs. The CNMP Core Curriculum provides a consi stent background and framework from 36 which state or regionally specific CNMP courses can be developed. There are ten sections in the 37 Comprehensive Nutrient Management Plan (CNMP) Core Curriculum. The section topics are: 382

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Chapter 2. Agriculture 2-185 • Introduction to a Comprehensive Nutrient Management Plan 1

• Conservation Planning 2

• Land Treatment Practices 3

• Manure and Wastewater Storage and Handling 4

• Nutrient Management 5

• Feed Management 6

• Record Keeping 7

• Air Quality 8

• Alternative Utilization 9

• TSP Certification 10

Link: http://www.abe.iastate.edu/wastemgmt/cnmp-curriculu m.html Accessed retrieved January 11 26, 2010 12
65. Manure Management Planner Tutorials—Univ. of Mi ssouri Extension 13 These tutorials were part of a training program for Missouri nutrient management planners. The 14 tutorials outline many of the steps in developing a nutrient management plan in MMP. Many of 15 the steps in using MMP are universal among all stat es. These tutorials were developed in 2005 16 for an earlier version of MMP, but the authors beli eve that the tutorials are still mostly applicable 17 to the planning process when using MMP. Separate tu torials were developed for a swine 18 operation (liquid manure), poultry operation (solid manure) and fertilizer plan (no manure). 19

Link: http://www.nmplanner.missouri.edu/software/mmp_tuto rial.asp Accessed Retrieved 20 January 22, 2010 21