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Chapter 2. Agriculture 2-1 

1 Chapter 2. Agriculture 

2. 

2 Contents 

3 1. Purpose and Overview ........................................................................................................... 2-3 

4 1.1 Need for Agricultural Chapter Update.......................................................................... 2-3 

5 1.1.1 Purpose................................................................................................................. 2-3 

6 1.1.2 Intended Audience ............................................................................................... 2-3 

7 1.1.3 Water Quality Significance of Agricultural Runoff in the Chesapeake Bay 

8 Watershed ............................................................................................................ 2-3 

9 1.1.4 Managing Agricultural Runoff to Reduce Nutrient and Sediment Loss.............. 2-5 

10 1.2 Overview of the Agriculture Chapter ........................................................................... 2-6 

11 1.2.1 Management Practices and Management Practice Systems ................................ 2-6 

12 1.2.2 Implementation Measures for Agriculture in the Chesapeake Bay Watershed 

13 to Control Nonpoint Source Nutrient and Sediment Pollution............................ 2-9 

14 2. Implementation Measures and practices for Source Control and Avoidance...................... 2-11 

15 2.1 Row Crop Agriculture................................................................................................. 2-11 

16 2.1.1 Nutrient Management ........................................................................................ 2-15 

17 2.1.2 Alternative Crops............................................................................................... 2-20 

18 2.1.3 Land Retirement................................................................................................. 2-20 

19 2.1.4 Chemical Fertilizer Application, Storage, and Transport .................................. 2-21 

20 2.2 Animal Agriculture ..................................................................................................... 2-22 

21 2.2.1 Animal Feed Management................................................................................. 2-23 

22 2.2.2 Manure Storage, and Transport.......................................................................... 2-26 

23 2.2.3 Livestock Exclusion from Streams .................................................................... 2-27 

24 2.2.4 Wastewater and Animal Wastes ........................................................................ 2-29 

25 3 Implementation Measures and Practices for In-field Control.............................................. 2-48 

26 3.1 Field Nutrient Management ........................................................................................ 2-48 

27 3.2 Sediment and Erosion Control.................................................................................... 2-62 

28 3.3 Cover Crops ................................................................................................................ 2-72 

29 3.4 Pasture Land Management.......................................................................................... 2-76 

30 3.5 Drainage System Design............................................................................................. 2-83 

31 4. Implementation Measures and Practices for Edge- of- Field Trapping and Treatment....... 2-87 
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Chapter 2. Agriculture 2-2 

1 4.1 Buffers and Minimum Setbacks.................................................................................. 2-87 

2 4.2 Wetlands ................................................................................................................... 2-100 

3 4.3 Drainage Water Management ................................................................................... 2-109 

4 4.4 Animal Feeding Operations ...................................................................................... 2-121 

5 5. References.......................................................................................................................... 2-127 

6 Appendix 1: USDA Conservation Practice Standards (Practice Codes)Referenced 

7 throughout the document ................................................................................................... 2-156 

8 Appendix 2: Agricultural Tools in Support of Section 502 Technical Guidance.................... 2-165 

9 I. Software and Models ................................................................................................ 2-168 

10 II. Calculators, Spreadsheets, and Graphical Tools....................................................... 2-174 

11 III. Compilations of Tools............................................................................................... 2-176 

12 IV. Guidance and Other Technical Resources ................................................................ 2-177 

13 
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Chapter 2. Agriculture 2-3 

1 1. Purpose and Overview 

2 1.1 Need for Agricultural Chapter Update 

3 1.1.1 Purpose

4 Approximately 87,000 farm operations and 8.5 million acres of cropland, or nearly a quarter of 

5 the watershed, in the Chesapeake Bay watershed provide food and fiber, as well as significant 

6 natural areas and aesthetic and environmental benefits. Farms in the Chesapeake Bay watershed 

7 are very diverse. They vary greatly in size and produce a wide variety of products. Today, 

8 according to the U.S. Department of Agriculture (USDA), more than 50 commodities are 

9 produced in this region. The area’s primary crops include corn, soybeans, wheat, hay, pasture, 

10 vegetables, and fruits. The eastern part of the region is also home to a rapidly expanding nursery 

11 and greenhouse industry. 

12 This chapter’s The purpose of this chapter is to provide a host of cost-effective practices and 

13 actions that can be employed to reduce the input of nitrogen (N), phosphorus (P), and sediment 

14 from agricultural activities to local waters and the Chesapeake Bay. The This chapter focuses on 

15 nutrient management on row crop lands and in the production area of animal feeding operations 

16 (AFOs) and on the prevention of soil erosion from row crop lands. For information regarding the 

17 management of agricultural lands to protect and restore water quality by reducing impacts from 

18 pesticides, irrigation, and grazing, seethe user should reference the chapters devoted to those 

19 activities in the National Management Measurers for the Control of Nonpoint Pollution from 

20 Agriculture (USEPA, 2003). 

21 1.1.2 Intended Audience 

22 This chapter of this guidance is written for a broad audience, namely, all those involved in the 

23 planning, managingmanagement, and implementing implementation of agricultural activities. 

24 This documentguidance should be useful for USDA, including local Natural Resources 

25 Conservation Service (NRCS) staff, NRCS conservation practice standard developers, and 

26 Conservation Districts as they work hand-in-hand with the producers in their respective counties 

27 and watersheds. This chapter is also intended to be a useful tool for nutrient management 

28 planners, technical service providers (TSPs), farm operators, landland owners, and drainage 

29 district staff. The documentguidance also provides assistance to those planning and protecting or 

30 restoring areas of concern, such as TMDL developers and nonpoint source planners. Finally, this 

31 chapter can also provide citizens with a better understanding of how agricultural activities can be 

32 managed to protect and restore the Chesapeake Bay. 

33 1.1.3 Water Quality Significance of Agricultural Runoff in the Chesapeake 

34 Bay Watershed 

35 Agriculture is the single largest source of nutrients and sediments to the Chesapeake Bay, 

36 responsible for 43 percent of the Nnitrogen, 45 percent of the Pphosphorus, and 60 percent of the 

37 sediment loads. Much of thatthis load is delivered from Pennsylvania (Susquehanna River), 
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Chapter 2. Agriculture 2-4 

1 Virginia (Shenandoah and Potomac riversRivers), and the Delmarva Peninsula of Maryland, 

2 Delaware, and Virginia. Chemical fertilizer accounts for 17 percent of the Nnitrogen and 19 

3 percent of the Pphosphorus load, and manure accounts for 19 percent of the Nnitrogen and 26 

4 percent of the Pphosphorus load. Seven percent of the total nitrogen (TN) load comes from air 

5 deposition from livestock and soil emissions from agriculture. 

6 Implementing agricultural management practices mightmay not provide nutrient load reductions 

7 to the Chesapeake Bay as quickly as implementing actions by other sectors; however, reductions 

8 in agricultural loads are the most cost-effective means to restore the bayBay over time. Excess 

9 Nnitrogen from cropland is transported to the bayBay via groundwater with a lag time of years or 

10 decades, depending on the location in the watershed. Additionally, reductions in Pphosphorus

11 loads from agricultural lands mightmay not be seen immediately after implementing P-following 

12 implementation of phosphorus control practices because of due to current Pphosphorus

13 saturation in cropland soils in areas with high animal densities. Reductions in nutrient loadings to 

14 the bayBay from the agricultural sector are essential to achieve the desired water quality goals; 

15 therefore, expedited implementation of effective land management practices agricultural will be 

16 critical to reaching the 2025 goals. 

17 Historical Context of Agriculture in the Chesapeake Bay Watershed 

18 Since European settlement, agriculture has played an important role in sustaining the people of 

19 the Chesapeake Bay watershed. In the 1650s, the land was first broadly cleared for timber and 

20 agriculture. The land was able to support the growing population and in the 1700s, as agriculture 

21 expanded, the first signs of environmental degradation were noted. By the 1750s, 20 to 30 

22 percent of the forested areas were stripped for settlement, and the shipping ports begin to fill 

23 with eroded sediment. By the 1800s, plows were used widely in agriculture, beginning the 

24 onslaught of permanent tillage, preventing reforestation and encouraging soil erosion. In the first 

25 half of the 1800s, the Chesapeake and Delaware canal project encouraged even broader 

26 expansion of agriculture. Half of the forests were cleared for agriculture and settlement, and the 

27 first imported fertilizers (bird guano) were used from the Caribbean and from nitrate deposits on 

28 the northern Chilean coast. 

29 Agriculture in the Chesapeake Bay Watershed Today 

30 Immediately following World War II, chemical fertilizer use became widespread, and as 

31 suburban expansion began in the 1950s, wetlands were drained and filled. In the 1980s, nutrient 

32 management efforts began to take hold in agriculture, and in the 1990s, Chesapeake Bay 

33 tributary strategies were put in place, setting goals for reductions of nutrient and sediment 

34 loadings to the bay. TodayBay. Currently, for assessment purposes, the bay Bay and its tidal 

35 tributaries are broken into 92 segments. The statesThese segments have been identified those

36 segments by the states as being impaired becausesince they do not meet water quality standards, 

37 and a total maximum daily load (TMDL) will be prepared for each of the these segments, 

38 collectively adding up to the Chesapeake TMDL. The TMDL will be a calculation of the 

39 maximum amount of a pollutant that the bayBay can receive and still safely meet water quality 

40 standards. 

41 Approximately 25 percent of the land in the Chesapeake Bay watershed is used for agriculture. 

42 The practices that some landowners and operators use to maximize their crop yields can cause 
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Chapter 2. Agriculture 2-5 

1 deterioration in the quality of the bayBay and its watershed. When farm operators improperly 

2 apply fertilizers and pesticides, thosethese materials can flow off the land and deliver excess N, 

3 Pnitrogen, phosphorus, and chemicals to the bayBay. The nutrients and bacteria in animal 

4 manure, which is used for fertilizer, can seep into groundwater and run into waterways if 

5 managed improperly on-site at an AFOanimal feeding operation or off-site on cropland or 

6 elsewhere. Poor tilling and irrigation practices can promote erosion and can lead to additional 

7 sediment loads being delivered to waterbodies. At the outflow of the tiles or along the edge of 

8 drains, there is a high potential exists for loss of streamside vegetation and sediment scouring 

9 (seeSee chapters 5 and 7). ThoseThese practices can be improved, enhanced, or modified as 

10 appropriate to reduce pollutant loads from agriculture throughout the Chesapeake Bay watershed. 

11 1.1.4 Managing Agricultural Runoff to Reduce Nutrient and Sediment Loss 

12 Recommended Water Pollution Control Strategy: Implementation of Next Generation 

13 Nutrient Management Plans 

14 To reach the bay Bay goals, the Chesapeake Bay Executive Order calls for implementation of the 

15 next generation of tools and actions (Chesapeake Bay Program Office, 2010). While nutrient 

16 management planning has been a part of farm operations since the 1980s because of due to state 

17 program requirements, this document presents a description of Next Generation Nutrient 

18 Management Plans (NGNMPs) based on upon the state-of- or the art science and understanding 

19 of the farm landscape today. To meet the bayBay goals, NGNMPs can be implemented 

20 throughout the Chesapeake Bay watershed on all row crop lands and by all animal operations in 

21 the watershed. NGNMPs will provide a strong link between production, nutrient management on 

22 the land, and water quality. The NGNMPs described in this document will enable producers to 

23 achieve their expected yields and reduce waste of the valuable, finite resources of nutrients and 

24 sediments, while reducing the losses of the nutrients and sediments to surface water that 

25 eventually enters the Chesapeake Bay. 

26 Although agriculture is a key part of the solution to the Chesapeake Bay restoration given the 

27 magnitude of loads and the relative cost-effectiveness of practices, we must overcome there are 

28 significant barriers to be overcome to reach broad-scale implementation in agriculture. While the 

29 draft Executive Order.O. section 203 Federal Strategy notes that restoration of the Chesapeake 

30 Bay or its watershed is not expected for many years, restoration will require a renewed 

31 commitment and therefore actions taken throughout the agricultural landscape must become 

32 more strategic, coordinated, and goal-oriented to meet the bayBay goals (Federal Leadership 

33 Committee, 2009). 

34 The most significant improvement in agricultural production needed to restore the Chesapeake 

35 Bay is the need to change how excess manure nutrients are handled. To meet the 2025 nutrient 

36 goals for the Chesapeake Bay, the agricultural community will need to broadly adopt new 

37 markets and alternative manure uses will need to be broadly adopted by the agricultural 

38 community. Doing so will not only be an essential step toward the Chesapeake Bay goals, but it 

39 will help agriculture become more sustainable and profitable. While the major focus of this 

40 document is nutrient management, there are sections in this chapter are devoted to practices and 

41 actions for AFOanimal feeding operation production areas as well as sediment and erosion 

42 control on row crop lands. 
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Chapter 2. Agriculture 2-6 

1 The most effective practices that producers can be widely implement implemented to reduce the 

2 inputs of nutrients to the Chesapeake Bay focus on controlling the control of the rate, timing, 

3 method and form of nutrient application. According to the best information currently available, 

4 in order for the Chesapeake Bay restoration goals to be achieved, NGNMPs to accomplish such 

5 control will need to be implemented on nearly all row crop agriculture lands and nearly all 

6 production areas of AFOsanimal feeding operations in the Chesapeake Bay. This guidance 

7 presents the implementation measures component of NGNMPs that would maximize reductions 

8 by agriculture. 

9 Achieving Multiple Benefits 

10 The benefits and services provided by well- managed agriculture in the Chesapeake Bay 

11 watershed are numerous, and include sustained crop yields; restored waterbodies for drinking 

12 water, recreational, and other beneficial uses; habitat benefits; a functioning ecosystem; reduced 

13 vulnerability to invasive species; and a continued healthy and productive agricultural economy in 

14 the Chesapeake Bay watershed. When effective land cover from agriculture occurs year-round, 

15 thosethese systems can store carbon and minimize soil erosion that buries local waters and the 

16 bayBay. A healthy agricultural network in the bayBay watershed will provide for key 

17 connections across the landscape for animals and birds, as well as reduce the watershed’s 

18 vulnerability to flooding and the effects of climate change. 

19 ReadersIt is recommended that readers of this chapter shouldguidance document also see refer to 

20 Chapters 4 and 5 regarding Forestry and Riparian Buffers. While this chapter focuses on source 

21 control and treatment options for row crop and animal production areas in agriculture, it is 

22 essential that a holistic restoration of the Chesapeake Bay watershed also achieve the benefits 

23 that can be reaped when all of these systems are operating together to serve the watershed. 

24 1.2 Overview of the Agriculture Chapter

25 This chapter provides recommendations for the suite of practices that should be implemented in 

26 the Chesapeake Bay watershed to meet the agriculture sector reduction goals by 2025. While 

27 these recommendations are made from recent state-of-the-art literature, the chapter expands upon 

28 the Management Measure for Nutrients described in the National Management Measures to 

29 Control Nonpoint Pollution from Agriculture (USEPA, 2003). 

30 1.2.1 Management Practices and Management Practice Systems 

31 Management practices are implemented on agricultural lands for a variety of purposes, including 

32 protecting water resources, protecting terrestrial or aquatic wildlife habitat, and protecting the 

33 land resource from degradation by wind, salt, and toxic levels of metals. The primary focus of 

34 this guidance is on agricultural management practices that reduce the delivery of pollutants into 

35 water resources by reducing pollutant generation or by remediating or intercepting pollutants 

36 before they enter water resources. 

37 NRCS maintains a National Handbook of Conservation Practices (USDA-–NRCS, 1977), 

38 updated continuously, which details nationally accepted management practices. ThoseThese

39 practices are on can be viewed at the USDA-NRCS Web site at 
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Chapter 2. Agriculture 2-7 

1 http://www.nrcs.usda.gov/technical/efotg/.http://www.nrcs.usda.gov/technical/efotg/. In addition 

2 to the NRCS standards, many states use locally determined management practices that are not 

3 reflected in the NRCS handbook. NoteIt must be noted that while a wide variety of practices are 

4 available, all require regular inspection and maintenance to ensure continued performance at 

5 expected levels. Readers interested in obtaining information on management practices currently 

6 used in their area should contact their local Soil and Water Conservation District or local USDA 

7 office. Two very helpful handbooks for farmers are 60 Ways Farmers Can Protect Surface 

8 Water (Hirschi et al. 1997), and 50 Ways Farmers Can Protect their Ground Water (Hirschi et 

9 al. 1993). 

10 Management practices are used to control a particular pollutant type from specific land uses. For 

11 example, conservation tillage is used to control erosion from irrigated or non-irrigated cropland. 

12 Management practices can may also provide secondary benefits by controlling other pollutants, 

13 depending on how the pollutants are generated or transported. For example, practices thatwhich

14 reduce erosion and sediment delivery often reduce Pphosphorus losses because Psince 

15 phosphorus is strongly adsorbed to silt and clay particles. Thus, conservation tillage not only 

16 reduces erosion and , but also reduces transport of particulate Pphosphorus. 

17 In some cases, a management practice canmay provide environmental benefits beyond those 

18 linked to water quality. For example, riparian buffers, which reduce Pphosphorus and sediment 

19 delivery to waterwater bodies, also serve as habitat for many species of birds and plants. 

20 Sometimes, however, management practices used to control one pollutant mightmay

21 inadvertently increase the generation, transport, or delivery of another pollutant; management 

22 practices should be implemented through a systems approach to ensure balance. Conservation 

23 tillage, because it creates increased soil porosity (i.e., large pore spaces), canmay increase nitrate 

24 leaching through the soil, particularly when an adjustment to the amount and timing of Nnitrogen

25 application is not part of the management plan. Tile drains, used to reduce surface runoff and 

26 increase soil drainage, can also have the undesirable effect of concentrating and delivering 

27 Nnitrogen directly to streams (Hirschi et al. 1997). To In order to reduce the Nnitrogen pollution 

28 caused by tile drains, other management practices, such as nutrient management for source 

29 reduction and biofilters that treat the outflow of the tile drains, mightmay be needed. On the 

30 other hand, practices that which reduce runoff mightmay contribute to reduced in-stream flows, 

31 which have the potential to adversely affectimpact habitat. Therefore, management practices 

32 should only be chosen only in the context of a holistic evaluation of both the benefits and 

33 potential adverse effectsimpacts of the suite of practices, or management system, to be 

34 implemented at a site. 

35 Some management practice systems include both repetitive treatment by the same practice at 

36 different places in a field as well as diversification of practices to enhance all of the benefits of 

37 each. An example of such a system is an animal waste management system in which some 

38 components are included to help others function. For example, diversions and subsurface drains 

39 mightmay be necessary to convey runoff and wastes to a waste treatment lagoon for treatment. 

40 While the diversions and subsurface drains mightmay not provide any measurable pollution 

41 control of their own, they are essential to the overall performance of the animal waste 

42 management system. Other components, such as lagoons and waste utilization plans, are added 

43 to provide repetitive treatment. 
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Chapter 2. Agriculture 2-8 

1 Note on Practice Effectiveness: The effectiveness of any management practice is a function of a 

2 variety of factors including the characteristics of the baseline condition (e.g., influent water 

3 quality, soil nutrient levels, and current management practices), slope, soil type, climate, crops, 

4 and weather conditions during the study. Further, the monitoring and assessment approach used 

5 in a study imparts significant limitations to interpreting the interpretation of the findings. For 

6 example, inflow-outflow studies can be used to assess pollutant removal, but only if the outflow 

7 and inflow measurements pertain to the same parcel of water. Load and concentration reductions 

8 have different meanings and utility, and it is particularly important to have full understanding of 

9 the comparison or benchmark against which the reduction is measured. The following summary 

10 of literature findings on the effectiveness of agricultural management practices and systems must 

11 be interpreted carefully, and EPA it is strongly recommendsrecommended that the reader review 

12 full reports be reviewed before applying the findings to any specific situation.

13 This chapter is divided into three separate sections regarding specific control options. 

14 GenerallyThere are generally three areas exist in agricultural production in whichwhere, 

15 following the path of nutrients and sediment can be controlled: sediments from their source until 

16 they reach the edge of the field:

17 • Section 2: Nutrient and sediment source control and avoidance from row crop and animal 

18 production areas;

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

20 • Section 4: Row crop edge- of- field trapping and treatment.

21 Controlling the sources of nutrients and sediment entering the Chesapeake Bay through a variety 

22 of approaches will minimize the pollutants available throughout the agricultural operation. 

23 Source control and avoidance pertains to a crop’s ability to use the nutrients available throughout 

24 the growing season, cropping cycles, feed management, manure management, and chemical 

25 fertilizer management. Source control approaches for cropland carefully evaluate the proper rate, 

26 timing, method, and form of nutrient application. This guidance separately discusses the two 

27 critical topics of row crop agriculture and animal agriculture, each focusing on the specific 

28 control actions that can take place when designing and implementing these distinct aspects of 

29 farm operations.

30 The row crop in-field controls focus on nutrient and sediment controls throughout the field itself. 

31 In-field practices will impede the transport and/or delivery (or both) of pollutants, either by 

32 reducing water transported, and thus the amount of the pollutant transported, or by depositing

33 through deposition of the pollutant into less harmful forms into the soil or atmosphere. 

34 Wetlands, drainage water management, and buffers and setbacks are examples of important 

35 edge- of- field or end- of- pipe measures to prevent nutrient loads to the Chesapeake Bay. 

36 In this chapter, we present a set of implementation measures for agricultural production that are 

37 intended to be implemented together as a comprehensive management system in order to achieve 

38 the overall agricultural sector goals for reducing the runoff of nutrients and sediments to the 

39 Chesapeake Bay by 2025. These implementation measures are organized into the three 

40 components of source control and avoidance, in-field control, and edge-of-field trapping and 

41 treatment. The specific set of practices to be chosen by an agricultural producer to achieve 
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Chapter 2. Agriculture 2-9 

1 pollutant reductions will necessarily be tailored as appropriate based on a variety of factors 

2 related to the landscape, agricultural operation, and other similar factors.

3 1.2.2 Implementation Measures for Agriculture in the Chesapeake Bay 

4 Watershed to Control Nonpoint Source Nutrient and Sediment 

5 Pollution 

6 Source Control and Avoidance 

7 Row Crop Agriculture 

8 The implementation measures are 

9 • Base P phosphorus application on Pphosphorus saturation in soils as follows: If soil 

10 phosphorus (P) saturation levels are above 20 percent, do not apply to row crops manure 

11 or commercial fertilizer that contains Pphosphorus nutrients to row crops. When soil 

12 saturation level allows for application (i.e., is below that level), apply at an N-based rate,

13 and determine P application rate using nutrient use efficiency (NUE) of the crop to be 

14 planted. Also, instigate a soil-P monitoring plan to ensure that soil-P levels are staying 

15 steady over time, and if they are increasing, adjust P -rates; if soil-P levels increase above 

16 20 percent P saturation, no longer apply P.

17 • Implement Nnitrogen fertilizer use efficiency (a subset of nutrient use efficiency, or 

18 NUE) to maximize the net benefit from the lowest-needed amount of manure or 

19 commercial fertilizer Nnitrogen nutrients entering the row crop system. When applying 

20 Nnitrogen, consider rate, timing, and form of manure as well. 

21 • Replace high nutrient loading crops in high-risk areas for water quality effectsimpacts

22 with sound alternatives. 

23 • Retire highly erodible lands (HELs) from both cropland and pasture, and replace them 

24 with perennial native vegetation. 

25 • Minimize commercial fertilizer use where manure nutrients are available. When 

26 commercial fertilizer use is necessary, provide for the proper storage and calibration and 

27 operation of chemical fertilizer nutrient application equipment. 

28 Animal Agriculture 

29 The implementation measures are 

30 • Manage animal feed to minimize for nutrients in excretion that is then used as manure 

31 fertilizer for all livestock. 

32 • Safely and strategically apply (with properly calibrated equipment),),, store, and transport 

33 manure fertilizer nutrients. Liquid manure storage systems should be (1a) designed to 

34 safely store the entire quantity and contents of animal manure and wastewater produced, 

35 contaminated runoff from the facility, and rainfall from the 25-year, 24-hour storm and 

36 (2b) consistent with planned utilization rates or utilization practices and schedule. Dry 

37 manure, such as that produced in certain poultry and beef operations, should be stored in 
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Chapter 2. Agriculture 2-10 

1 production buildings, storage facilities, or otherwise covered to prevent precipitation 

2 from coming into direct contact with the manure. 

3 • Exclude all livestock from streams and streamstream banks to reduce nutrient inputs, 

4 stream bank erosion, sediment inputs, and improve animal health.

5 • Process/treat through physical, chemical, and biological processes all facility wastewater 

6 and animal wastes to reduce as much as practicable the volume and loss of nutrients. 

7 Row Crop In-Fieldfield Control 

8 The implementation measures are 

9 • Manage nutrient applications to row crop land to minimize nutrients available for runoff. 

10 In doing so, apply manure and chemical fertilizer application only during the growing 

11 season only, do not apply any manure to frozen ground, inject or otherwise incorporate 

12 all manure or organic fertilizer to minimize the available dissolved P and volatilized N, 

13 and do not apply nutrients to HELs. 

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

15 • Use conservation tillage or continuous no-till on all row crops to reduce soil erosion and 

16 sediment loads except on those lands that currently have no erosion or sediment loss. 

17 • Use the most suitable cover crops for the site on all acres that have received any manure 

18 or chemical fertilizer application. Cover crops should be used during a non-growing 

19 season (including winters)), or when there is bare land in a field. 

20 • Minimize nutrient and soil loss from pasture land by maintaining uniform livestock 

21 distribution over the pasture, keeping livestock away from riparian areas, and managing 

22 stocking rates and vegetation to prevent pollutant losses through erosion and runoff. 

23 • Where subsurface drainage is added to an agricultural field, design the system to 

24 minimize the discharge of Nnitrogen through tile drains.

25 Row Crop Edge-of-Field Trapping and Treatment 

26 The implementation measures are 

27 • Integrate into farm plans fertilizer application buffers or minimum setbacks from in-field 

28 ditches, intermittent streams, tributaries, and surface waters from fertilizer application 

29 into farm plan. 

30 • Protect and restore wetlands and riparian areas from adverse effects and maintain 

31 suchthis nonpoint source abatement function while protecting other existing functions of 

32 thethese wetlands and riparian areas as measured by characteristics such as vegetative 

33 composition and cover, hydrology of surface water and groundground water, 

34 geochemistry of the substrate, and species composition.

35 • For both new and existing subsurface drainage systems, use controlled drainage, ditch 

36 management, and bioreactors as necessary to minimize off-farm transport of nutrients.

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

38 areas to minimize off-farm transport of nutrients and sediment. 
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Chapter 2. Agriculture 2-11 

1 2. Implementation Measures and practices for Source 

2 Control and Avoidance 

3 2.1 Row Crop Agriculture 

4 In the Chesapeake Bay watershed, the overall delivery of agriculture-based nutrients in to the 

5 bayBay needs to decrease significantly in order to protect the quality of the Chesapeake Bay. 

6 Unfortunately, at present, a significant nutrient imbalance exists in the bayBay watershed so that 

7 there is an excess of Pphosphorus being produced in the Bay's watershed, resulting in excess 

8 Pphosphorus being available for delivery to the bayBay through surface and ground waters. 

9 Nationwide, 1997 USDA estimates show that most U.S. counties (78 percent) need to move 

10 manure Pphosphorus from at least some animal operations to avoid Pphosphorus accumulation. 

11 AlsoAdditionally, 1997 USDA estimates show that poultry operations account for two-thirds of 

12 Nnitrogen at farms and one-half of excess P, because of due to less land and higher P-content of 

13 the manure. Dairy and hog operations also contribute to excess on-farm P. 

14 The Mid-Atlantic Water Program (MAWP), a consortium of land grant universities in the 

15 Chesapeake Bay watershed, presents nutrient budgets and balances by county and state for 2007 

16 (MAWP, 2007). The nutrient budgets are defined as “a summary of the major nutrient inputs and 

17 outputs to the cropland in a geographic region,” and the nutrient balances are defined as “the 

18 difference between nutrient inputs and outputs.” When the nutrient balance is close to zero, 

19 nutrients applied in manure and fertilizer are closely matched to crop useutilization. When the 

20 nutrient balance is positive, nutrient inputs exceed outputs. When the nutrient balance is 

21 negative, nutrient outputs exceed inputs. 

22 The MAWP has developed maps, in which nutrient input equals the amount of manure and 

23 fertilizer nutrient available for application, and nutrient output is determined by the amount of 

24 nutrient taken up by the crop, measured in the plant biomass. TheThese maps do not account for 

25 the level of nutrients that are already contained in the soil before prior to application of 

26 additional nutrient inputs; thus, the reader should recognize that in places where there is a zero 

27 balance, it mightmay seem that nutrients are being appropriately managed. However, , however, 

28 if there are high soil nutrients are available in those these areas, there couldmay be nutrient loss. 

29 TheThis analysis identifies three of these hotspots in the Shenandoah River Valley in Virginia, 

30 on the Eastern Shore of Maryland, and in the areas including and surrounding Lancaster County 

31 in Pennsylvania (Figures 2-1 and 2-2). 
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Chapter 2. Agriculture 2-12 

1 

2 

Source: MAWP 2007

Note: The darkest color indicates counties with the highest N balances.

3 Figure 2-1. The map shows the Nnitrogen balance for cropland in Mid-Atlantic counties in 2007. 

4 Darkest color indicates county with highest nitrogen balances. (MAWP, 2007)
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Chapter 2. Agriculture 2-13 

1 

2 

3 Figure 2-2. The map shows the phosphorus balance for cropland in Mid-Atlantic counties in 2007. 
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Chapter 2. Agriculture 2-14 

1 

2 

Source: MAWP 2007

Note: The darkestDarkest color indicates countiescounty with the highest Pphosphorus balances.

3 Figure 2-2. The map shows the P balance for cropland in Mid-Atlantic counties in (MAWP, 2007.

4 )
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Chapter 2. Agriculture 2-15 

1 The following section details practices and actions that producers can implementbe implemented

2 to minimize excess nutrients from entering the agricultural production system, to work 

3 towardtowards balance. 

4 2.1.1 Nutrient Management 

5 The nutrient management tools and practices currently in widespread use in the Chesapeake Bay 

6 watershed for both organic (manure, sludge, and suchetc.) and inorganic (commercial fertilizer) 

7 application are insufficient to prevent over-application and the resulting nutrient loading to the 

8 Chesapeake Bay. However, smart nutrient management planning, if broadly applied in the Bay 

9 watershed, will significantly reduce nutrients available as runoff into local waters and the 

10 Chesapeake Bay. 

11 The goal of nutrient management planning is to apply nutrients at rates necessary to achieve 

12 realistic crop yields, improve the timing of nutrient application, and employ appropriate tools to 

13 determine the method and form of application. When manure is the source of fertilizer, both the 

14 nutrient value and the rate of availability of the nutrients should must be determined, whereas 

15 with commercial fertilizer that information is generally made available on the label. Where 

16 legume crops are planted, the Nnitrogen contribution of the plant itself should be determined and 

17 credited. 

18 Nutrient management planning is implemented to increase the efficiency with which crops use 

19 applied nutrients are used by crops, thereby reducing the amount available to be transported to 

20 both surface and ground waters. Controlling the source of nutrients by practicing effective 

21 nutrient management is imperative, and reducing the nutrient inputs into the agricultural system 

22 will effectively minimize nutrient losses from row crops occurring at the edge-of-field by runoff 

23 and by leaching from the root zone. Once N, Pnitrogen, phosphorus, or other nutrients are 

24 applied to the soil, their movement is largely controlled by the movement of soil and water and 

25 must therefore be managed through other control systems such as erosion control and irrigation 

26 water management. ThatThis is usually achieved by developing a nutrient budget for the crop, 

27 applying nutrients at the proper time with proper methods, applying only the types and amounts 

28 of nutrients necessary to produce a crop, and considering the environmental hazards of the site. 

29 In cases where manure is used as a nutrient source, manure holding areas mightmay be needed to 

30 provide capability to apply manure at optimal times. 

31 In many instances, nutrient management planning results in using the use of less commercial 

32 fertilizer needed because of due to the availability of manure nutrients and, therefore, a reduction 

33 in production costs. However the current agriculture system in the Bay watershed has a general 

34 imbalance of nutrients due to excess manure generated annually by the combination of all 

35 AFOsanimal feeding operations in the watershed. Thus, for any row-crop land where there has 

36 not been a balanced use of nutrients over a recent past, nutrient management planning should 

37 incorporate options for source control—the reduction of nutrients for input into the agricultural 

38 production system—in order to reduce the possibility of excess nutrients being applied out of 

39 need to reduce capacity of manure. 

40 Producers, when planning nutrientNutrient management, planning should consider all aspects of 

41 the rate, timing, method and form of nutrients, consistentlyin a consistent and coordinated 
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Chapter 2. Agriculture 2-16 

1 usingmanner based upon the host of data that can be available through effective use of nutrient 

2 use tools. Nutrient management plans typically focus mainly on Nnitrogen and Pphosphorus, the 

3 nutrients of greatest concern for water quality, and it is important to consider all sources of these 

4 nutrients as input into the agricultural system. The major sources of nutrients include the 

5 following: 

6 • Commercial fertilizers 

7 • Manures, sludges, and other organic materials 

8 • Crop residues and legumes in rotation 

9 • Irrigation water 

10 • Soil reserves 

11 Smart nutrient management planning can significantly reduce costs. The total cost of a nutrient 

12 management system are those costs associated with manure nutrient application, plus the 

13 disposal of alternative use cost, or penalty cost, for manure that cannot be applied within a 

14 reasonable local transport area, less the savings incurred by reduced commercial fertilizer. 

15 Because Nnitrogen and Pphosphorus behave very differently, basic understanding of how 

16 Nnitrogen and Pphosphorus are cycled in the soil-crop system is an important foundation for 

17 effective nutrient management. The National Management Measures to Control Nonpoint 

18 Pollution from Agriculture (USEPA, 2003) is an excellent sourcereference describing the 

19 technical details of each of the these nutrient sources and cycles in agriculture. 

20 NNitrogen is continually cycled among plants, soil organisms, soil organic matter, water, and the 

21 atmosphere in a complex series of biochemical transformations. Some Nnitrogen forms are 

22 highly mobile, while others are not. At any given time, most of the Nnitrogen in the soil is held 

23 in soil organic matter (decaying plant and animal tissue) and the soil humus. Mineralization 

24 processes slowly transform the Nnitrogen in soil organic matter by microbial decomposition to 

25 ammonium ions (NH4+), releasing them into the soil where they can be strongly adsorbed and 

26 relatively immobile. Plants can use the ammonium, however, and it canmay be moved with 

27 sediment or suspended matter. Nitrification by soil microorganisms transforms ammonium ions 

28 (either mineralized from soil organic matter or added in fertilizer) to nitrite (NO2-) and then 

29 quickly to nitrate (NO3-), which is easily taken up by plant roots. Nitrate, the form of Nnitrogen

30 most often associated with water quality problems, is soluble and mobile in water. 

31 Immobilization includes processes by which ammonium and nitrate ions are converted to 

32 organic-N, through uptake by plants or microorganisms, and bound in the soil. Denitrification 

33 converts nitrate into nitrite (NO2) and then to nitrous oxide (N2O) and gaseous Nnitrogen through 

34 microbial action in an anaerobic environment. 

35 An NA nitrogen molecule canmay pass through thethis cycle many times in the same field. The 

36 processes in the Nnitrogen cycle can occur simultaneously and are controlled by soil organisms, 

37 temperature, and availability of oxygen and carbon in the soil. The balance among thethese

38 processes determines how much Nnitrogen is available for plant growth and how much canmay

39 be lost to groundground water, surface water, or the atmosphere. 

40 PPhosphorus lacks an atmospheric connection (although it can be transported via airborne soil 

41 particles) and is much less subject to biological transformation, rendering the Pphosphorus cycle 
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Chapter 2. Agriculture 2-17 

1 considerably simpler. Most of the Pphosphorus in soil occurs as a mixture of mineral and organic

2 materials. A large amount of Pphosphorus (50–75 percent) is held in soil organic matter, which 

3 is slowly broken down by soil microorganisms. Some of the organic Pphosphorus is released into 

4 soil solution as phosphate that is immediately available to plants. The phosphate released by 

5 decomposition or added in fertilizers is strongly adsorbed to soil particles and are rapidly 

6 immobilized in forms that are unavailable to plants. The equilibrium level of dissolved 

7 Pphosphorus in the soil solution is controlled by the chemical environment of the soil (e.g., pH, 

8 oxidation-reduction, iron concentration) and by the Pphosphorus content of the soil. 

9 Throughout the Chesapeake Bay watershed, thosethese processes are constantly occurring 

10 throughout agricultural lands. To In order to effectively plan, design, and implement controls, it 

11 is imperative to understand these basic scientific cycles. 

12 Phosphorus 

Implementation Measure: Base P application on P saturation in soils as follows: If soil 

phosphorus (P) saturation levels are above 20 percent, do not apply to row crops manure or 

commercial fertilizer that contains P nutrients. When soil saturation level allows for application 

(i.e., is below that level), apply at a N-based rate and determine P application rate using nutrient 

use efficiency (NUE) of the crop to be planted. Also, instigate a soil-P monitoring plan to ensure 

that soil-P levels are staying steady over time, and if they are increasing, adjust P -rates; if soil-P 

levels increase above 20 percent P saturation, no longer apply P.

13 Implementation Measure: Base phosphorus application on phosphorus saturation in soils 

14 as follows: If soil P saturation levels are above 20 percent, do not apply manure or 

15 commercial fertilizer that contains phosphorus nutrients to row crops. When soil 

16 saturation level allows for application (i.e., is below that level), apply at an N-based rate, 

17 and determine P application rate using nutrient use efficiency of the crop to be planted.

18 In the Chesapeake Bay watershed, where animal manure is a dominant and available source of 

19 fertilizer, there is an overabundance of Pphosphorus as fertilizer exists as described above.

20 Because P attaches to the soil particles and thus builds up in the soil, to protect water quality, P 

21 fertilizer application is dependent upon the existing soil-P levels. P does not pose an 

22 environmental risk when it is insoluble, which occurs when it is sorbed to soils. For there to be 

23 an environmental risk to exist that is associated with P the transport of P to surface waters, P 

24 must be in a form that can be released to water. Thus, the P saturation rate does not measure 

25 directly the risk for P loss in runoff; the P saturation rate indicates the amount of P that is 

26 desorbed and moved into solution (Kovzelove et al.., 2010). Butler and Coale (2005) describe 

27 how the P release from soil when in contact with water increases exponentially once the P 

28 saturation level is between 20– – 30 percent.

29 EPA recommendsIt is recommended that P fertilizer not be applied to soils that are in or above 

30 the range where P desorption and loss as runoff can occur. Thus, it is important for the nutrient 

31 management plan to addressconsider the slope and movement patterns for water as runoff in a 

32 field, because P saturation does not dictate the probability of P in runoff to move to a ditch or 

33 local waterbody.
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Chapter 2. Agriculture 2-18 

1 Tools There are tools that can be used to plan for the applicable rate, timing, form, and method 

2 of P fertilizer application. Understanding P saturation levels throughout the field in soils is 

3 necessary to ensure that the farmer is not applying P that is above the level needed for the crop 

4 and dually affecting water quality. P saturation level calculations can These tools have varying 

5 degrees of technical needs and can all be implemented with the assistance of NRCS, extension 

6 agents, TSPs, or other private industry consultants and researchers.

7 Beck et al. (2004) have calculated for three major physiographic regions of Virginia the degree 

8 of P saturation as a function of Mehlich 1 extractable P for soils. That calculation provides a 

9 useful model that can be adopted throughout the Chesapeake Bay watershed.

10 Nitrogen 

Implementation Measure: Implement N fertilizer use efficiency (a subset of NUE) to maximize 

the net benefit from the lowest-needed amount of manure or commercial fertilizer N nutrients 

entering the row crop system. When applying N, consider rate, timing, and form of manure as 

well.

11 Implementation Measure: Implement nitrogen fertilizer use efficiency (a subset of nutrient 

12 use efficiency, or NUE) to maximize the net benefit from the lowest-needed amount of 

13 manure or commercial fertilizer nitrogen nutrients entering the row crop system. When 

14 applying nitrogen, consider rate, timing, and form of manure as well.

15 Nutrient Use Efficiency (NUE), also known as precision agriculture or decision agriculture, 

16 relies on developing the Nnitrogen application rate on the basis ofbased upon in-field variability 

17 measured in real time. Practicing NUE to control the amount of N input into the system in row 

18 crop agriculture calibrates the yield potential to N needed by a plant, in order to ensure that N 

19 loss is minimized through reductions in leaching, surface flow, ammonia volatilization, 

20 nitrification and denitrification, and soil erosion. NUE is effective in reducing N loss when both 

21 the crop- removal efficiency (the efficiency of the crop to take in all Nnitrogen made available to 

22 it)), works in tandem with the increase in residual nutrients available from the soil during the 

23 time the crop is growing.

24 Producers’Currently, there is limited use of Nnitrogen use efficiency tools is limited in

25 reducingto reduce over-applied Nnitrogen from leaving the production field and entering into 

26 local waterways. NNitrogen use efficiency is critical because higher use efficiency reduces the 

27 level of excess Nnitrogen available to create potential environmental problems. 

28 NUE includes two main components:

29 • Crop removal efficiency, or the removal of nutrient in a harvested crop as a percent of 

30 nutrient applied to the crop (Mosier et al., 2004), and 

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

32 When developing the Nnitrogen application rate of a nutrient management plan for any row crop, 

33 NUE guides the farmer or planner through a series of steps to determine the rate. The first step is 

34 to commit to realistic production goals based on sound data to replace typical N application rates 

35 with levels based upon specific plant need requirements. The second step is to employ 
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Chapter 2. Agriculture 2-19 

1 precision/decision agriculture systems and tools to efficiently apply N though improved 

2 materials, timing, placement, and useutilization. A variety of in-field tests can be used to adjust

3 inputs in order to meet the optimum yield of the plant in a manner where N loss to the 

4 environment is minimized. 

5 Maryland and Delaware have determined a suite of practices that make up a decision agriculture 

6 program, and other states in the Chesapeake Bay watershed are actively considering similar 

7 approaches; there is a broad range of effective tools that can be used where applicable. The 

8 These tools have varying degrees of technical needs and can all be implemented with the 

9 assistance of NRCS, extension agents, TSPs, or other private industry consultants and 

10 researchers. These include, but are not limited to the following decision agriculture tools 

11 (additional tools and references arecan be found in Appendix 2.): 

12 • Stalk nitrate tests for field corn production is one of the best methods to estimate N 

13 application rate for subsequent years. The test is done at the end-of-season, and provides 

14 field specific data to know if the N available for crop uptake was deficient, marginal, 

15 optimal, or in excess for the plant to produce the optimum yield. The results of the this 

16 test can be used to improve the NUE practice, and the NUE effectiveness is enhanced 

17 when the results are shared among localized area farmers with comparable row crop 

18 production conditions. (Blackmer and Mallarino, 1996).

19 • Crop testing is a broader approach for a wider diversity of crops than the stalk nitrate 

20 test, but can include that tool for field corn production. Crop testing is used generally to 

21 detect the relative plant available N by sight with a leaf color chart or chlorophyll meter, 

22 measuring plant available soil N with the Pre-Sidedress Nitrate Test (PSNT)), or 

23 employing real time chlorophyll measurement for variable rate application in the field.

24 • Fertilizer prescription rate maps can be a very useful tool in NUE; theythese are 

25 developed using strategic soil testing and global positioning system (GPS) crop yield 

26 monitoring data. Soil tests are conducted throughout a field using based on soil property 

27 characteristics and GPS crop yield data mapping to measure the soil nutrient supplying 

28 capacity, to chart the field variability of immobilized N, to determine realistic crop 

29 production levels, and to help determine and to assist in determining the subsequent 

30 season’sseason's appropriate nutrient prescriptive application rates. 

31 • To maintain existing soil fertility levels, crop nutrient removal can be used to measure 

32 the difference between the application rate and the plant uptake rate. Simple charts can be 

33 devised to employ this tool, yet there are specific software programs are available to ease 

34 the calculations. 

35 • Aerial imagery and strip trials are individual tools, but when coupled at the end of a 

36 season, can provide an effective means to understand the spatial variability of a field 

37 remotely. This can also lend an understanding of field areas where there are signs of 

38 planter or applicator skips, diseased or pest- damaged areas, weed infestations and other 

39 non-uniform areas, which can decrease the amount of plant available N required to meet 

40 crop needs. 

41 • Protein maps can be developed from real- time sensing of plant and grain characteristics. 

42 Plant and grain analysis allows the farmer to evaluate the effectiveness of previous 
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Chapter 2. Agriculture 2-20 

1 nutrient management tools and practices to manage fertilizer application throughout the 

2 field. 

3 • Nutrient source integration is used generally with organic fertilizer (manure), as a part 

4 of developing a manure management plan. This tool provides multiple benefits and is 

5 used to determine subsequent season’sseason's manure needs and can simplify manure 

6 application records. 

7 • A tool being developed for the future is environmental risk assessment. This considers 

8 the location of the field and its potential to impair local or far-field areas usingbased upon

9 known transport factors. 

10 2.1.2 Alternative Crops 

Implementation Measure: Replace high nutrient loading crops in high-risk areas for water 

quality effects with sound alternatives.

11 Implementation Measure: Replace high nutrient loading crops in high-risk areas for water 

12 quality impacts with sound alternatives.

13 High-risk areas exist in places where there is intense animal agriculture because of , due to the 

14 resulting imbalance in nutrients. High-nutrient-loading crops, such as corn and soybean, should 

15 be replaced with alternatives in environmentally sensitive areas such as areas in close proximity 

16 to local waters. 

17 Local agricultural contacts such as extension agents, conservation district staff, and consultants 

18 can provide the best assistance in choosing alternative crops while meeting production goals. In 

19 Maryland, the document Alternative Agriculture in Maryland: A Guide to Evaluate Farm-Based 

20 Enterprises (Musser, et al. 1999) provides a workbook with 78 separate decision worksheets. 

21 The USDA National Agricultural Library document Alternative Crops & Enterprises for Small 

22 Farm Diversification (Gold and Thompson, 2009) provides a broad range of information on 

23 alternative crops. 

24 2.1.3 Land Retirement 

Implementation Measure: Retire highly erodible lands (HELs) from both cropland and pasture,

and replace them with perennial native vegetation.

25 Implementation Measure: Retire highly erodible lands (HELs) from both cropland and 

26 pasture, and replace them with perennial native vegetation.

27 The methodology used in implementing the Farm Bill Conservation Reserve Program has 

28 encouraged the retirement of highly erodible lands (HELs) from both cropland and pasture and 

29 replacement with perennial vegetation. 

30 When thethese lands are retired through the federal program, a set of environmental benefit 

31 indicators are considered: 
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Chapter 2. Agriculture 2-21 

1 • Water quality benefits from reduced erosion, runoff, and leaching 

2 • Wildlife habitat benefits resulting from covers on contract acreage 

3 • On-farm benefits from reduced erosion 

4 • Benefits that will likely endure 

5 • Air quality benefits from reduced wind erosion 

6 • Cost 

7 ThoseThese indicators can be used to assess environmentally sensitive areas as well as USDA8 identified HELs to determine where they are in the Chesapeake Bay watershed. Nutrients should 

9 not be applied to HELs, even if thethese lands are in continued row crop production. When lands 

10 are retired from production, regardless of their sensitivity to runoff and erosion, their associated 

11 nutrient inputs become null. 

12 When HELs follow parallel to stream channels, producers should employ the recommendations 

13 from Chapters 5 and 7 (Riparian and Hydromodification)) should be employed as the perennial 

14 vegetation. 

15 2.1.4 Chemical Fertilizer Application, Storage, and Transport 

Implementation Measure: Minimize commercial fertilizer use where manure nutrients are 

available. When commercial fertilizer use is necessary, provide for the proper storage and 

calibration and operation of chemical fertilizer nutrient application equipment.

16 Implementation Measure: Minimize commercial fertilizer use where manure nutrients are 

17 available. When commercial fertilizer use is necessary, provide for the proper storage and 

18 calibration and operation of chemical fertilizer nutrient application equipment.

19 Inorganic, commercial fertilizers represent the largest single source of Nnitrogen and 

20 Pphosphorus applied to most cropland in the United States.S. In the Chesapeake Bay watershed, 

21 commercial fertilizers are used when manure is not readily available. Major commercial fertilizer 

22 Nnitrogen sources include anhydrous ammonia, urea, ammonium nitrate, and ammonium sulfate. 

23 Major Pphosphorus fertilizer sources include monoammonium phosphate, diammonium 

24 phosphate, triple superphosphate, ammonium phosphate sulfate, and liquids. Descriptions of 

25 common fertilizer materials are given in Table 2--1.

26 Table 2-1. Common commercial fertilizer minerals 

Analysis

(%)

Common name chemical formula N P2O5 K2O

N Analysis (%)

Common Name Chemical Formula N P2O5 K2O

Nitrogen materials 

Ammonium nitrate NH4NO3 34% 0% 0%

Ammonium sulfate (NH4 )2SO4 21% 0% 0%

Ammonium nitrate-urea NH4NO3+(NH2 )2CO 32% 0% 0%
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Chapter 2. Agriculture 2-22 

Anhydrous ammonia NH3 82% 0% 0%

Aqua ammonia NH4OH 20% 0% 0%

Urea (NH2 )2CO 46% 0% 0%

Phosphate materials 

Superphosphate Ca(H2PO4)2 0%

20%–-

46%

0%

Ammoniated superphosphate Ca(NH4H2PO4)2 5% 40 0%

Monoammonium phosphate NH4H2PO4 13% 52% 0%

Diammonium phosphate (NH4)2HPO4 18% 46% 0%

Urea-ammonium phosphate 

(NH2)2CO+(NH4)2HPO4 

28% 28% 0%

Potassium materials 

Muriate of potash KCl 0% 0% 60%

Monopotassium phosphate KH2PO4 0% 50% 40%

Potassium hydroxide KOH 0% 0% 70%

Potassium nitrate KNO3 13% 0% 45%

Potassium sulfate K2SO4 0% 0% 50%

Note: Adapted fromSource: Pennsylvania State University (. 1997) and. The Penn State 

Agronomy Guide, 1997-1998, University Park, PA. Cornell Cooperative Extension (. 1997). 

1997 Cornell Recommendations for Integrated Field Crop Management. Resource Center, 

Cornell University, Ithaca, NY.

1 

2 Commercial fertilizers offer the advantage of allowing exact formulation and delivery of nutrient 

3 quantities specifically tailored to the site, crop, and time of application in concentrated, readily 

4 available forms. The use of any particular material or blend is governed by the characteristics of 

5 the formulation (such as volatilization potential and availability rate), suitability for the particular 

6 crop, crop needs, existing soil test levels, economics, application timing and equipment, and 

7 handling preferences of the producer. 

8 However, because of due to the nutrient imbalance from the amount of livestock manure 

9 produced in the Chesapeake Bay watershed, EPA recommendsit is recommended that producers 

10 minimize commercial fertilizer use of commercial fertilizer be minimized where manure 

11 nutrients are available to be used. EPAIt is also recommendsrecommended that provisions be in 

12 place for storing the storage of fertilizer, as well as properly calibratingthe proper calibration and 

13 operatingoperation of commercial fertilizer application equipment. 

14 

15 2.2 Animal Agriculture 

16 In the Chesapeake Bay watershed, because of the intensity of animal agriculture and manure 

17 generation, enhancing nutrient source control is imperative in the production area. All 

18 AFOsanimal feeding operations should provide the capacity to store (1) all liquid manure 

19 generated and contents of animal manure and wastewater produced, (2) contaminated runoff 

20 from the facility and rainfall events in the geographic area, (3) dry manure, such as that produced 
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Chapter 2. Agriculture 2-23 

1 at poultry operations, in production buildings or storage facilities or otherwise with a cover. All 

2 AFO personnelanimal feeding operations should also ensure there is no runoff of pollutants is 

3 occurring from the production area or dischargeddischarges through conveyances to local waters, 

4 including any precipitation-related water that comes into contact with the animals, animal by5 products, litter, or feed. Regarding theThe location of manure storage systems, producers should 

6 consider proximity to waterwater bodies, floodplains, HELs, and other environmentally sensitive 

7 areas. 

8 Strategies for source control associated with animal agriculture focus on containing and treating 

9 feed, manure, and facility wastewater and preventing their movement to surface waters. Four 

10 general principles can help control sources of nutrients and other pollutants from animal 

11 agriculture: animal feed management, manure storage and transport, treatment or processing of 

12 wastes, and management of grazing livestock. 

13 2.2.1 Animal Feed Management 

14 Important feeding strategies for livestock production focus on adjustment of feed additives, 

15 formulations, or feeding methods to reduce the nutrient content or change the form of nutrient 

16 excreted in manure. Decreasing the Pphosphorus and Nnitrogen content of manure through diet 

17 modification is a powerful, cost-effective approach to reducing the nutrient balance and nutrient 

18 losses from livestock farms (Knowlton et al. 2004; Maguire et al. 2007; Swink et al. 2009). 

19 Reduction of Pphosphorus and Nnitrogen overfeeding, use of feed additives to enhance dietary 

20 Pphosphorus and Nnitrogen utilization, and development of grains in which a high proportion of 

21 the P is available (high-available P grains) have all been shown to decrease fecal Pphosphorus

22 and Nnitrogen excretion without impairing animal performance (Maguire et al. 2005). 

Implementation Measure: Manage animal feed to minimize for nutrients in excretion that is 

then used as manure fertilizer for all livestock.

23 Implementation Measure: Manage animal feed to minimize for nutrients in excretion that 

24 is then used as manure fertilizer for all livestock.

25 Practice Effectiveness 

26 Arriaga et al. (2009) estimated that dietary manipulation in Spain could decrease dairy herd 

27 Nnitrogen excretion by 11 percent per hectare, whereas P phosphorus would be decreased by 17 

28 percent. On two New YorkNY dairy farms, Cerosaletti et al. (2004) reported that fecal P 

29 concentrations decreased 33 percent following dietary adjustments; milk production was not 

30 adversely affected. In a modeling study of the same New YorkNY farms, precision feed 

31 management reduced the P imbalance on each farm and reduced the soluble P lost to the 

32 environment by 18 percent (Ghebremichael et al. 2007). Ebeling et al. (2002) applied dairy 

33 manure from two dietary P levels to corn land in Wisconsin and reported that at equivalent 

34 manure rates, dissolved P concentration in runoff from the high P diet manure was 10 times 

35 higher (2.84 versusvs. 0.30 mg/ L) than the low P diet manure, and four times higher (1.18 

36 versusvs. 0.30 mg/L) when applied at equivalent P rates. 

37 In a review, Graham et al. (2003) reported that including the inclusion of xylanase or phytase in 

38 poultry feeds can reduce manure volume by up to 14 percent and N and P outputs by up to 13 
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Chapter 2. Agriculture 2-24 

1 percent and 70 percent, respectively. A review by Powers and Angel (2008) reported that for 

2 each 1 percent reduction in dietary crude protein, estimated NH3 losses are decreased by 10 

3 percent; 20–40 percent reductions in NH3 emissions from poultry houses have been reported. For 

4 P, under commercial conditions, broiler litter P was decreased by 30 percent when diet P was 

5 decreased by 10 percent. In North Carolina, Leytem et al. (2008) reported that inclusion of 

6 phytase in poultry diets at the expense of inorganic P or reductions in dietary available P 

7 decreased litter total phosphorus (TP) P by 28 to 43 percent. Litter water-soluble P decreased by 

8 up to 73 percent with an increasing dietary Ca/available P ratio, irrespective of phylase addition. 

9 Nahm (2009) reported that phytase addition to simple gastric animal diets in South Korea can 

10 decrease the litter water-soluble P concentration by 30–35 percent. In Arkansas, Smith et al. 

11 (2004) showed that phytase and high-available P corn diets reduced litter-dissolved P content in 

12 broiler litter by 10 and 35 percent, respectively, compared with the normal diet (789 mg P/kg). 

13 PPhosphorus concentrations in runoff water were highest from plots receiving poultry litter from 

14 the normal diet, whereas plots receiving poultry litter from phytase and high- available P corn 

15 diets had reduced P concentrations. 

16 In Canada, Emiola et al. (2009) showed that complete removal of inorganic P from growing pig 

17 diets coupled with phytase supplementation improves digestibility and retention of P and N, thus 

18 reducing manure P excretion without any negative effect on pig performance. In another 

19 Canadian study, Grandhi (2001) reported that replacing inorganic P with phytase and lowering 

20 the dietary protein level while supplementing amino acids in swine diets can decrease the 

21 excretion of P up to 44 percent and N up to 28 percent in manure with no adverse effect on 

22 performance of pigs. In a Danish study, replacing inorganic phosphates with phytase in pig feed 

23 reduced the concentration of P in slurry by 35 percent (Sommer et al. 2008). In Europe, Aarnink 

24 and Verstegen (2007) found that a combination of lowering crude protein intake and increasing 

25 fermentable carbohydrates, and other modifications to feeding strategies could reduce ammonia 

26 emission from growing-finishing pigs by 70 percent.

27 Table 2-2. Summary of reported practice effects resulting from changes in animal feeding 

28 strategies.

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 manureamanure1

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 

2008 
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Chapter 2. Agriculture 2-25 

Location

Study 

type Practice Practice effects Source 

NC Animal 

trials 

Phytase in 

poultry feed 

28–43% decrease in litter Ttotal 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 cornccorn3

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 

strategiesdstrat

egies4

70% reduction in ammonia emissions from 

growing-finishing operations 

Aarnink and 

Verstegen 2007 

Notes:

a. Footnotes:

1

highHigh-P diet manure and low-P diet manure applied at equivalent P rates 

b. 2 withWith increasing Ca/available P in feed, irrespective of phytase 

c. 3 studyStudy also reported that P concentrations in plot runoff were reduced where litter from modified diets was 

applied 

d.4 Feeding changes included lowering crude protein intake, increasing fermentable carbohydrates, and addition of 

acidifying salts 

1 

2 Possible case study outlining plain sect collaboration

3 Watson Run (Lancaster Co) PA Agricultural assessment pilot project.

4 24 farms involved, 19 agreed to allow us to test private wells. Mostly Plain Sect.

5 Public health concerns can drive clean water efforts on nutrient control beyond where they 

6 could otherwise go. Lancaster is the highest manure nutrient concentration in the Bay 

7 watershed.

8 Drinking Water Sampling Results

9 Sampled 19 out of 24 farm wells

10 9 out of 19 contained Total coliform bacteria

11 6 out of 19 contained E. coli bacteria

12 16 out of 19 exceeded the MCL for nitrate
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Chapter 2. Agriculture 2-26 

1 2.2.2 Manure Storage, and Transport 

Implementation Measure: Safely and strategically apply (with properly calibrated equipment), 

store, and transport manure fertilizer nutrients. Liquid manure storage systems should be (1) 

designed to safely store the entire quantity and contents of animal manure and wastewater 

produced, contaminated runoff from the facility, and rainfall from the 25-year, 24-hour storm 

and (2) consistent with planned utilization rates or utilization practices and schedule. Dry 

manure, such as that produced in certain poultry and beef operations, should be stored in 

production buildings, storage facilities, or otherwise covered to prevent precipitation from 

coming into direct contact with the manure.

2 The manure and other wastes generated by livestock production should be contained and 

3 management should prevent runoff losses from the facility. Key measures and some component 

4 practices include the following:

5 Implementation Measure: Safely and strategically apply (with properly calibrated 

6 equipment), store and transport manure fertilizer nutrients. Liquid manure storage 

7 systems should be (a) designed to safely store the entire quantity and contents of animal 

8 manure and wastewater produced, contaminated runoff from the facility, and rainfall from 

9 the 25-year, 24-hour storm and (b) consistent with planned utilization rates or utilization 

10 practices and schedule. Dry manure, such as that produced in certain poultry and beef 

11 operations, should be stored in production buildings, storage facilities, or otherwise 

12 covered to prevent precipitation from coming into direct contact with the manure.

13 The manure and other wastes generated by livestock production must be contained and 

14 management must prevent runoff losses from the facility. Key measures and some component 

15 practices include:

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

17 – Waste storage facility (NRCS Practice Code 313): A waste impoundment made by 

18 constructing an embankment, and/or excavating a pit or dugout, or by fabricating a 

19 structure. 

20 – Waste treatment lagoon (NRCS Practice Code 359): An impoundment made by 

21 excavation or earth fill for biological treatment of animal or other agricultural wastes.

22 • Ensure that manure and litter are stockpiled safely. 

23 – Set clean-out schedules that ensure no poultry litter stockpiling during times of the 

24 year with the greatest environmental losses, (e.g., winter). 

25 – Do not stockpile manure without covers and liners. 

26 – Divert clean water away from waste storage areas. 

27 – Diversion (NRCS Practice Code 362): A channel constructed across the slope 

28 with a supporting ridge on the lower side. 

29 – Roof runoff management (NRCS Practice Code 558): A facility for controlling 

30 and disposing of runoff water from roofs. 

31 • Ensure that any recipient of manure has planned effectively to meet, at a minimum, the 

32 same performance goals as those of the sourced manure. 
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Chapter 2. Agriculture 2-27 

1 – Areas receiving manure should be managed in accordance with meeting the goals for 

2 erosion and sediment control, irrigation, and grazing management applicable, 

3 including practices such as crop and grazing management practices to minimize 

4 movement of nutrient and organic materials applied, and buffers or other practices to 

5 trap, store, and process materials that might move during precipitation events. 

6 – Waste utilization (NRCS Practice Code 633): Using agricultural wastes or other 

7 wastes on land in an environmentally acceptable manner while maintaining or 

8 improving soil and plant resources. 

9 There is little recent literature quantifying the effectiveness of the practices in this category. 

10 Some basic effectiveness information has been cited in National Management Measures to 

11 Control Nonpoint Pollution from Agriculture (USEPA, 2003). 

12 2.2.3 Livestock Exclusion from Streams 

Implementation Measure: Exclude all livestock from streams and streambanks to reduce 

nutrient inputs, stream bank erosion, sediment inputs, and improve animal health.

13 Implementation measure: Exclude all livestock from streams and stream banks to reduce 

14 nutrient inputs, stream bank erosion, sediment inputs, and improve animal health.

15 Grazing livestock should be excluded from streams and riparian areas to reduce direct nutrient 

16 and pathogen inputs, prevent streambank damage and resulting sediment inputs, and improve 

17 animal health. Fencing is the most reliable way to protect streams and riparian areas from the 

18 effectsimpacts of livestock. Fencing can be woven wire or electric; cost-share programs 

19 mightmay require permanent fencing, rather than temporary or movable fence. Management 

20 intensive or rotational grazing couldmay, however, involve using the use of movable fences to 

21 create temporary paddocks to direct livestock away from a water course. If complete fencing is 

22 not possible, the most sensitive streambank areas should be fenced, while providing limited areas 

23 for access to drinking water for grazing animals. Some trials have documented success in 

24 keeping livestock out of streams without continuous fencing by providing drinking water and/or 

25 shade or both away from the stream to encourage livestock to congregate away from riparian 

26 areas.

27 Practice Effectiveness 

28 Livestock exclusion fencing 

29 Line, et al. (2000) documented 33, 78, 76, and 82 percent reductions in weekly nitrate + nitrite, 

30 total Kjeldahl nitrogen (TKN), total phosphorus (TP), and sediment lends, respectively, resulting 

31 from fencing dairy cows from a 10- to 16- m wide riparian corridor along a small North Carolina 

32 stream. In the same system, Line (2003) showed that fecal coliform and enterococci levels 

33 decreased 65.9 percent and 57.0 percent, respectively, after livestock exclusion. 

34 In Vermont streams draining dairy pastures, Meals (2002) reported 20–50 percent reductions in 

35 nutrient and suspended solids loads and 40–60 percent reductions in fecal bacteria counts 

36 following livestock exclusion and riparian restoration with bioengineering techniques. 
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Chapter 2. Agriculture 2-28 

1 James, et al. (2007) estimated 32 percent reduction of in-stream deposition of fecal Pphosphorus

2 by grazing dairy cattle in New York following livestock exclusion under the CREP. 

3 In central Pennsylvania, Carline and Walsh (2007) reported that following riparian treatments, 

4 consisting of fencing, 3- to 4-m buffer strips, stream bank stabilization, and rock-lined stream 

5 crossings, stream bank vegetation increased from 50 percent or less to 100 percent in formerly 

6 grazed riparian buffers, suspended sediments during base flow and storm flow decreased 47–-87 

7 percent in both streams, and macroinvertebrate densities increased in two treated streams. 

8 However, Agouridis, et al. (2005) reported that incorporation of an alternate water source and/or 

9 fenced riparian area along a central Kentucky stream did not significantly alter stream cross10 sectional area over treatment reaches. The authors suggested that riparian recovery within the 

11 exclosures from pretreatment grazing practices mightmay require decades, or greater 

12 intervention (i.e., stream restoration), before a substantial reduction in streambank erosion is 

13 noted. 

14 Alternative water supply 

15 In Georgia, Franklin, et al. (2009) found that when the temperature and humidity index (THI) 

16 ranged between 62 and 72, providing cattle with water troughs outside of riparian zones tended 

17 to decrease time cattle spent in riparian zones by 63 percent. The study suggests that water 

18 troughs placed away from unfenced streams may improve water quality by reducing the amount 

19 of time cattle spend in riparian zones. 

20 However, Line (2003) reported that levels of most measured physical parameters and bacteria 

21 were not significantly different following the installation of alternate water supply in a North 

22 Carolina pasture. 

23 Table 2-3. Summary of reported practice effects resulting from livestock exclusion.

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 

cattleacattle1

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 2003 
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Chapter 2. Agriculture 2-29 

Location Study type Practice Practice effects Source 

counts 

Note:

a.Footnotes:

1

 Livestock exclusion under Conservation Reserve Enhancement Program (CREP)

1 

2 2.2.4 Wastewater and Animal Wastes 

Implementation Measure: Process/treat through physical, chemical, and biological processes 

all facility wastewater and animal wastes to reduce as much as practicable the volume and loss of 

nutrients.

3 Implementation measure: Process/treat through physical, chemical, and biological 

4 processes all facility wastewater and animal wastes to reduce as much as practicable the 

5 volume and loss of nutrients.

6 Manure and wastewater stored on farms has a significant pollution potential even after wastes are 

7 collected and stored appropriately. Researchers have recommended a variety of practices to 

8 manage the effectsimpacts of animal wastes, focusing on treating treatment of waste to change 

9 its physical, chemical, or biological properties;, remove potential pollutants;, or improve 

10 handling characteristics (Bicudo and Goyal 2003; Ritter et al. 2003; Martinez et al. 2009).

11 Such practices These include the following: 

12 • Waste treatment and processing—treating manure or farm wastewater to separate 

13 liquids and solids, immobilize pollutants, or remove nutrients from the wastestream

14 • waste stream;

15 • Digestion—processing animal wastes to capture biogas for use as fuel, reducing bulk of 

16 remaining residuals for further management;

17 • Composting—composting of animal wastes, possibly combined with other green wastes, 

18 to reduce bulk, stabilize nutrient forms, and facilitate export and land application of 

19 animal wastes;

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

21 denitrification;

22 • Other biological treatments—treatment systems using microorganisms, algae, or other 

23 plants to break down wastes and absorb nutrients;

24 • Air quality management—practices to reduce or capture airborne pollutants like 

25 ammonia or fine particulates from animal housing 

26 Practice Effectiveness 

27 Waste treatment and processing—manure and wastewater amendment 

28 Amending poultry litter with alum [Al3(SO4)2-14H2O] has received considerable attention as a 

29 method of economically reducing ammonia volatilization in the poultry house and soluble P
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Chapter 2. Agriculture 2-30 

1 phosphorus in runoff waters. In South Korea, Do et al. (2005) reported that application of 

2 aluminum chloride (AlCl3-6H2O) to litter lowered atmospheric ammonia concentrations at 42 

3 days by 97.2 percent%, whereas ferrous sulfate (FeSO4-7H2O) lowered it by 91 percent%. 

4 Ammonia concentrations were reduced by 86, 79, 76, and 69 percent% by alum, alum + CaCO3, 

5 aluminum chloride + CaCO3, and potassium permanganate (KMnO4), respectively, when 

6 compared with a control at 42 days. The addition of 6.25 percent% zeolite or 2.5 percent% alum 

7 to dairy slurry in Maryland reduced ammonia emissions by nearly 50 and 60 percent%, 

8 respectively. Alum treatment retained ammonia by reducing the slurry pH to 5 or less. In 

9 contrast, zeolite, (a cation exchange medium) adsorbed ammonium and reduced dissolved 

10 ammonia gas (Lefcourt and Meisinger 2001). 

11 In Arkansas, Moore et al. (1998 and 2000) reported that reductions in litter pH in alum-treated 

12 broiler litter reduced NH3 volatilization by 97 percent%, which led to reductions in atmospheric 

13 NH3 in the alum-treated houses. Broilers grown on alum-treated litter were significantly heavier 

14 than controls (1.73 kg versusvs. 1.66 kg). Soluble reactive P (SRP) concentrations in runoff from 

15 pastures fertilized with alum-treated litter were 75 percent lower than those from normal litter. 

16 Also in Arkansas, Smith et al. (2001) found that alum and aluminum chloride amendment to 

17 swine manure reduced SRP concentrations in runoff by 84 percent and were not statistically 

18 different from SRP concentrations in runoff from unfertilized control plots. Smith et al. (2004) 

19 reported that the addition of alum to the various poultry litters reduced P runoff from pastures 

20 where the litter was applied by 52 to 69 percent; the greatest reduction occurred when alum was 

21 used in conjunction with dietary modification with high available phosphorus (HAP) corn and 

22 phytase. 

23 In Pennsylvania, Dou et al. (2003) reported reductions of soluble P in dairy, swine, and broiler 

24 manures of 80 to 99 percent at treatment rates of 100 to 250 g alum/kg manure dry matter. 

25 Fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60 percent at a rate of 

26 400 g/kg for all three manures. Flue gas desulfurization by-product (FGD) reduced soluble P by 

27 nearly 80 percent when added to swine manure and broiler litter at 150 and 250 g/kg. 

28 In laboratory studies, alum reduced ortho-P in dairy wastewater 93–-99 percent at rates less than 

29 3 g alum/L. Ortho-P was reduced to 1 mg P/L or less by a combination of alum and 

30 polyacrylamide (PAM) treatment (Jones and Brown 2000). 

31 Oh et al. (2005) reported that alum and polymer addition improved the efficacy of mechanical 

32 separation of dairy manure. When compared to the control, waste amended with alum and 

33 polymer had 82 percent less TP in the press liquor, which indicates that P was partitioned into 

34 the press cake. The combined alum/polymer treatment also resulted in a 36 percent reduction in 

35 total solids (TS) and a 71 percent reduction in chemical oxygen demand (COD) in the press 

36 liquor when compared to the control. 

37 Codling et al. (2000) recommended substituting Al-rich drinking water treatment residuals 

38 (WTR) for alum for reducing water-soluble P in poultry litter. In Ohio, Dayton and Basta (2005) 

39 reported that blending WTRwater treatment residuals to manure at 250 g/kg or reduced CaCl2 –

40 extractable P by > 75 percent. In a Vermont study, Meals et al. (2007) found that additions of 

41 alum-based WTRwater treatment residuals to liquid dairy manure could reduce manure soluble P 

42 concentrations up to 79 percent and Ttotal P concentrations by up to 50 percent. 
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Chapter 2. Agriculture 2-31 

1 In Idaho, Entry and Sojka (2000) reported that treatment of cattle and swine manure with 

2 combinations of PAMpolyacrylamide, Al(SO4)3, and CaO treatments reduced fecal bacteria 

3 counts by 10- to 10001,000-fold in water flowing downstream of treated manure application 

4 sites, compared to the untreated manure control. 

5 In Taiwan, Cheng (2001) was able to reduce COD levels in swine wastewater by 54 percent to 

6 190 mg/L using coagulants such as aluminum chloride, ferric chloride, calcium hydroxide, and 

7 polyaluminate chloride (PAC). 

8 Table 2-4. Summary of reported practice effects resulting from waste amendment.

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+CaCO3), 76% 

(aluminum chloride+CaCO3), 69% 

(KMnO4) 

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 

appliedaapplied1

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 PAMpolyacrylamide

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 WTRwater 

treatment residuals reduced CaCl2-

extractable P >75% 

Dayton and 

Basta 2005 

VT Laboratory Dairy manure 

amendment 

Amending dairy manure with alum-based 

WTRwater treatment residuals reduced 

manure soluble P up to 79%, Ttotal P up to 

50% 

Meals et al. 

2007 
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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 conjunction with dietary modification 

1 Waste treatment and processing—waste separation 

2 Note that waste separation does not treat wastes in the sense of removing or inactivating 

3 pollutants; rather, the process of separation produces a separate liquid and solid waste stream that 

4 may facilitate handling, transport, and further use of waste components. 

5 An inclined stationary screen separator removed 61 percent of the TStotal solids, 63 percent of 

6 the volatile solids, 49 percent of the TKN, 52 percent of the organic–N, and 53 percent of the 

7 Ttotal P from South Carolina dairy manure in a flush system; the complete manure treatment 

8 system consisting of the screen separator, separator, a two–chambered settling basin, and a 

9 lagoon removed 93 percent of the TS, 96 percent of the VS, 74 percent of the TKN, 91 percent of 

10 the organic–N, and 86 percent of the Ttotal P (Chastain et al. 2001). 

11 In Wisconsin, Converse and Karthikeyan (2004) reported that long-term settling of flushed dairy 

12 manure will remove 75 to 80 percent of TP from raw flushed manure or separator effluent and 

13 concentrate it in the bottom 25 percent of the volume. Cantrell et al. (2008) reported that 

14 geotextile filtration of liquid dairy manure in South Carolina reduced volume to less than 1 

15 percent of total influent volume concentrated the solids and nutrients in the dewatered material 

16 16 to 21 times greater than the influent, and retained 38 percent of TS, 26 percent of TAN, and 

17 45 percent of TP. In South Carolina, Garcia et al. (2009) used the natural flocculant chitosan to 

18 improve the performance of screen separation efficiencies for flushed dairy manure to > 95 

19 percent for total suspended sediment (TSS), > 73 percent for TKN, and > 54 percent for TP. 

20 Although screening alone was not effective for separating swine waste in a North Carolina study, 

21 Vanotti et al. (2002) found that adding PAM before screening increased separation efficiencies to 

22 95 percent TSS and volatile suspended solids (VSS), 92 percent organic P, 85 percent organic N, 

23 69 percent COD, and 59 percent BOD5; the N-P nutrient ratio was improved from 4.79 to 12.11, 

24 resulting in a more balanced effluent for fertilizing crops. In a subsequent study, Vanotti et al. 

25 (2005) reported that a combined flocculation and filtration treatment system removed 97 percent 

26 of TSS and VSS, 85 percent of BOD, 83 percent of COD, 61 percent TKN, and 72 percent of TP 

27 from flushed swine manure. 

28 Table 2-5. Summary of reported practice effects resulting from waste separation.

Location Study type Practice Practice effects Source 
3/15/2010 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 Ttotal 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 TPtotal P

Chastain et 

al. 2001 

WI Laboratory Long-term 

settling 

75-80% of Ttotal 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% BOD5; 

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 

1 Waste treatment and processing—lagoon treatment 

2 Waste treatment processes typically leave a residual material after producing a cleaner effluent; 

3 thus, the reductions cited in the literature generally refer to the treated effluent compared to the 

4 original waste. In all cases, the residual shouldmust be managed properly to prevent pollution 

5 impacts. 

6 Aerobic lagoon treatment of swine waste in Nova Scotia accomplished removals of 59–71 

7 percent TSS, 59–73 percent VSS, 42–60 percent TKN, and 42–51 percent NH4-N (Trias et al. 

8 2004). In France, combined aerobic/anoxic treatment of swine manure wastewater achieved 86 

9 percent reduction in TSS, 90 percent reduction in TN and COD (Prado et al. 2009); 50 percent of 

10 soluble P was biologically removed by an intermittent aerobic/anoxic sequence. 

11 In Korea, Ra et al. (1998) reported that a two-stage sequencing batch reactor system achieved 

12 removal efficiencies of 98 percent TOC, 100 percent NH4-N, 98 percent TKN, 97 percent 

13 orthoOrtho-P, 98 percent Ttotal P, 97 percent suspended solids (SS) and 97 percent volatile 

14 suspended solids (VSS). 
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Chapter 2. Agriculture 2-34 

1 Table 2-6. Summary of reported practice effects resulting from lagoon treatment.

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% NH4-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% NH4-N, 

98% TKN, 97% orthoOrtho-P, 98% Ttotal 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 BOD5, 85-98% 

of TKN and NH4-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 (2nd

generation) 

For swine waste treatment, removal of 98% 

TSS, 97% NH4-N, 95% TP, 99% Zn and Cu, 

99.9% odors, and 99.99% pathogens 

Vanotti and 

Szogi 2009 

2 Vanotti and Szogi (2008) tested a new swine waste treatment system combining liquid-solids 

3 separation with biological N and P removal in North Carolina and reported removal of 73–-98 

4 percent TSS, 40–76 percent of TS, 77–-100 percent of BOD5, 85–-98 percent of TKN and NH4-

5 N, 38–-95 percent of TP, and 37–-99 percent of Zn and Cu. A second-generation version of the 

6 system removed 98 percent TSS, 97 percent NH4-N, 95 percent TP, 99 percent Zn and Cu, 99.9 

7 percent odors, and 99.99 percent pathogens (Vanotti et al. 2009). 

8 Waste treatment and processing—other treatment 

9 Masse et al. (2007) reviewed the most recent literature on membrane filtration for manure 

10 concentration and treatment and found studies of ultrafiltration (UF) of manure that reported up 

11 to 100 percent removal of coliform and SS, 87 percent P reduction, but no effect on soluble COD 

12 from ultrafiltration (0.01 μm) and lower efficiency from microfiltration (0.2 μm), e.g., 75 percent 

13 SS removal. 

14 In Ireland, Healy et al. (2004) tested recirculating sand filters for treatment of dairy wastewater 

15 and reported TN reduction of 27 to 41 percent; TN reduction increased to 83 percent when sand 

16 filter effluent was recirculated through an anoxic zone. A subsequent study (Healy et al. 2007) 

17 reported consistent COD and TSS removals of greater than > 99 percent, and an 86 percent 

18 reduction in TN. 

19 Lee and Song (2006) reported average 81 percent COD, 92 percent SS, 68 percent TN, and 95 

20 percent TP removal using ozone to treat livestock wastewater through a dissolved air flotation 

21 system in Korea. Separation, collection, and treatment of swine waste with an ammonia recovery 

22 process using a metal ion treated resin bed achieved > 90 percent reduction in ammonia content 
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Chapter 2. Agriculture 2-35 

1 in North Carolina (Loeffler and van Kempen 2003). Removal of up to 90 percent of P from 

2 swine waste treated by chemical precipitation with struvite and hydroxyapatite was reported in 

3 South Korea (Choi et al. 2008). 

4 Table 2-7. Summary of reported practice effects resulting from other wastewater treatment.

Location 

Study 

type Practice Practice effects Source 

Numerous Review Membrane 

filtration 

Ultrafiltration (UF) (0.01 μm) of manure: up to 

100% removal of coliform and SS, 87% P 

reduction, no effect on soluble COD; lower 

efficiency from microfiltration (0.2μm: 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 

recoveryarecover

y

1

Achieved > 90% reduction in ammonia content in 

swine waste 

Loeffler and 

van Kempen 

2003 

Korea Farm Chemical 

precipitationbpre

cipitation2

Up to 90% removalRemoval of P from swine 

waste 

Choi et al. 

2008 

Notes:

a.Footnotes:

1

 Ammonia recovery using a metal ion treated resin bed 

b. Struvite2struvite and hydroxyapatite

5 Digestion 

6 Anaerobic digestion of manure can offer substantial benefits, both economic and intangible, to 

7 animal feeding operators and surrounding communities, such as renewable energy generation,; 

8 reduction in bulk and improvement of handling characteristics,; production of stable, liquid 

9 fertilizer and high-quality solid soil amendment; reduction in odors,; reduction of greenhouse 

10 gasses (GHGs);,; and reduction in ground and surface water contaminations (Demirer and Chen,

11 2005; Cantrell et al. 2008; Garrison and Richard 2005). There is ample literature [link to lit 

12 review?] concerning digester performance and yield, but not all studies report performance 

13 relevant to water quality concerns. It should be noted that digestion does not generally remove 

14 nutrients from the original waste material, and the residuals from digestion require further 

15 management. 

16 Costa et al. (2007) evaluated the efficiency of the anaerobic digestion in reducing the organic 

17 load of swine waste. Results showed an average reduction of COD of 58 percent. 
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Chapter 2. Agriculture 2-36 

1 In Turkey, Gungor-Demirci and Demirer (2004) investigated the potential biogas generation 

2 from anaerobic digestion of broiler and cattle manure. The efficiency of total COD removal was 

3 32–-43 percent and 40–-50 percent for initial COD concentrations of 12,000 and 53,500 mg/L, 

4 respectively. The biogas yields observed for initial COD concentrations of 12,000 and 53,500 

5 mg/Ll were 180–-270 and 223–-368 mLml gas/g COD added, respectively. 

6 A thermochemical conversion process applied to the treatment of swine manure for oil 

7 production in Illinois achieved a 75 percent reduction in COD (He et al. 2000). Lansing et al. 

8 (2008a) reported 84 percent reduction in COD and a 78 percent increase in dissolved NH4-N 

9 concentration in a study of seven low-cost digesters in Costa Rica. In a companion study of very 

10 small farms, Lansing et al. (2008b) reported reductions in COD of 86 percent for dairy digester 

11 and 92 percent for a swine digester. 

12 Thermophilic aerobic digestion reduced volatile solids by 28–-54 percent in Ireland, while 

13 producing Class A biosolids suitable for land application (Layden et al. 2007). Anaerobic 

14 digestion of poultry feces in Nigeria achieved > 99 percent reductions in E. coli bacteria counts 

15 compared to an undigested, but equal-aged control (Yongabi et al. 2009). 

16 In China, adding additional undigested swine wastewater to digested wastewater in a sequencing 

17 batch reactor process significantly improved with COD removal to > 80 percent and NH4-N 

18 removal up to 99 percent (Deng et al. 2005). The effluent COD concentration was in the range of 

19 250 mg/L to 350 mg/L and effluent NH4-N concentration was < 10 m/L. A pilot- scale 

20 sequencing batch reactor built to treat swine waste in Australia achieved NH4-N and odor 

21 reductions of > 99 percent as well as 79 percent removal of COD and a 49 percent reduction of 

22 PO4-P on a mass balance basis because ofdue to struvite formation within the reactor (Edgerton 

23 et al. 2000). 

24 In China, enhancement of a traditional sequencing batch reactor for swine waste with two-step 

25 feeding and low-intensity aeration at laboratory scale yielded reductions of 94 percent TN, 99 

26 percent TP, and 99.9 percent BOD5 , possibly reflecting the activity of denitrifying Pphosphorus27 accumulating organisms (Lue et al. 2008; Lu et al. 2009). 

28 Table 2-8. Summary of reported practice effects resulting from manure digestion.

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 mLml 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 NH4-

N 

Lansing et al. 

2008a 

Costa Farms Anaerobic 86% reductions of COD for dairy digester Lansing et al. 
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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 solidsasolids1Layden et al. 

2007 

Nigeria Farm Anaerobic 

digestion 

> 99% reductions in E. colibcoli2

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 

NH4-N removal up to 99% 

Deng et al. 

2005 

Australia Pilot Sequencing 

batch reactor 

For swine waste, > 99% NH4-N and odor 

reductions, 79% removal of COD, and a 49% 

reduction of PO4-P on a mass balance basisc

basis3

Edgerton et 

al. 2000 

China Laboratory Enhanced 

sequencing 

batch 

reactordreactor4

Reductions of 94% TN, 99% TP, and 99.9% 

BOD5 , possibly fromdue to growth of 

denitrifying Pphosphorus-accumulating 

organisms 

Lue et al. 

2008; Lu et 

al. 2009 

Notes:

a.Footnotes:

1

 Produced Class A biosolids suitable for direct land 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 aeration to traditional SBR

1 Composting 

2 Like digestion, composting of animal manure can reduce bulk, kill microorganisms, improve 

3 handling, and provide a value-added product (Brodie et al. 2000). While significant quantities of 

4 N canmay be lost through volatilization in the composting process (consider air quality issues), 

5 composting has little net effect on the Ttotal P content of the material. 

6 In Texas, (Bekele et al. (2006) documented a 19–23 percent decrease in soluble P in streams 

7 draining areas where significant quantities of manure had been composted and removed from the 

8 watershed.

9 Gibbs et al. (2002) measured nutrient losses from aerobic composting of cattle manure in the 

10 UK. Total mass loss ranged from 23 percent for an unturned static composting to 67 percent of 

11 the initial mass for the indoor composting turned three times. NNitrogen losses from the manure 

12 heaps ranged from 8 to 68 percent of the initial total manure N content. Gaseous N losses, 

13 primarily as NH3, accounted for between 7 and 67 percent of the initial manure N content. 

14 In beef feedlot manure composting in Alberta, Canada, Larney and Hao (2007) reported that 

exposure of manure to temperatures > 55 °

o

15 C for a period of 15 days appears to be an effective 

16 method of inactivating both Giardia cysts and Cryptosporidium oocysts in feedlot manure. The 

17 authors report mean carbon C and N concentrations in eight feedlot manure composts: total 

18 carbonTC 228 g/kg, TN 16.0 g/kg, soluble carbonC 11.3 g/kg, soluble N 1.6 g/kg. 
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Chapter 2. Agriculture 2-38 

1 Das et al. (2002) reported that co-composting of chicken hatchery waste and poultry litter was 

2 effective in eliminating 99.99 percent of E. coli bacteria in Georgia. Koenig et al. (2005) 

3 reported that aluminum sulfate and process controls such as moisture content, carbon source and 

4 particle size have the potential to reduce NH3 loss from poultry manure composted inside high5 rise layer structures. 
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Chapter 2. Agriculture 2-39 

1 Table 2-9. Summary of reported practice effects resulting from manure 

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 TNtotal N; 

gaseous N losses, primarily as NH3, accounted 

for 7%–67% of the initial manure N 

Gibbs et al. 

2002 

Canada Farm Aerobic 

composting 

Exposure to temperatures >55 °

oC 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 

3 Wetland treatment 

4 Wastewater from dairy and swine operations has been successfully treated in constructed 

5 wetlands (Hunt and Poach 2001). Plants are an integral part of wetlands. Cattails and bulrushes 

6 are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen 

7 transport to sediment. Improved oxidation and nitrification canmay also be obtained by using the 

8 use of the open water of marsh-pond-marsh designed wetlands. High levels of Nnitrogen

9 removal by denitrification have been reported from constructed wetlands, especially when the 

10 wastewater iswas partially nitrified (Hunt et al. 2009). Solids removal before prior to wetland 

11 treatment is essential for long-term functionality.

12 A constructed wetland to treat incoming barnyard runoff in Ireland retained > 60 percent% of the 

13 P load delivered to the wetland (Dunne et al. 2004). A subsequent study (Dunne et al. 2005) 

14 reported that P retention by the wetland varied with season (5–84 percent) with lowest retention 

15 occurring in winter. 

16 In a review of 12 constructed wetlands treating livestock wastewater on the south coast of 

17 Ireland, Harrington and McInnes (2009) reported that over an 8-eight year period, mean 

18 reduction of total and soluble P exceeded 95 percent and the mean removal of ammonium-N 

19 exceeded 98 percent. 

20 Mustafa et al. (2009) reported removal efficiencies of 98 percent BOD, 95 percent COD, 94 

21 percent SS, 99 percent ammonia N, 74 percent NO3-N, and 92 percent soluble P in dairy 

22 wastewater treatment through a constructed wetland system in Ireland. 

23 Lee et al. (2004) reported that average reduction efficiencies in subsurface flow constructed 

24 wetlands in Taiwan were: SS 96–99 percent, COD 77–84 percent, Ttotal P 47–59 percent, and 
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Chapter 2. Agriculture 2-40 

1 Ttotal N 10–24 percent. While physical mechanisms were dominant in removing pollutants, the 

2 contributions of microbial mechanisms increased with the duration of wetland use, achieving 48 

3 percent of COD removed and 16 percent of TN removed in the last phase. Water hyacinth made 

4 only a minimal contribution to the removal of nutrients. 

5 In Kansas, Mankin and Ikenberry (2004) evaluated a constructed wetland without vegetation as a 

6 sequencing batch reactor. Using 3; using three-week batch periods without plants, overall mass 

7 removal averaged 54 percent for COD, 58 percent for TSS, 90 percent for TN, 72 percent for 

8 NH4, -54 percent for NO3, 38 percent for TP, and -8 percent for PO4. 

9 Prantner et al. (2001) reported that a UK wetland system treating liquid swine manure after soil 

10 infiltration removed 94 percent of the NH3-N and NH4-N, 95 percent of the NO3-N, and 84 

11 percent of the TP.

12 total P. 

13 Flow of dairy wastewater through the wetland system in Maryland resulted in significant 

14 reductions in concentrations of all analytes except nitrate/nitrite (Schaafsma et al. 2000). Relative 

15 to initial concentrations, Ttotal N was reduced 98 percent, ammonia 56 percent, Ttotal P 96 

16 percent, ortho-P 84 percent, SSsuspended solids 96 percent, and BOD 97 percent. Nitrate/nitrite 

17 increased by 82 percent, although mean concentrations were much lower than concentrations of 

18 ammonia or TN

19 total nitrogen

20 In Nova Scotia, Smith et al. (2006) reported load reductions from 62 to 99 percent for BOD, 

21 TSS, TP, and NH3-N in wetlands treating agricultural wastewater. Also in Nova Scotia, Wood et 

22 al. (2008) reported mass reductions of 54 percent for Ttotal P and 53 percent soluble P over 

23 4four years in a surface flow constructed wetland milkhouse wash water and liquid manure. In 

24 Vermont, a subsurface flow constructed wetland with a slag filter removed 75 percent of P mass 

25 from dairy barnyard runoff and milk parlor waste (Weber et al. 2007). 

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

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-yearyr 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% NO3-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%, Ttotal P 47-59%, and 

TN total N10-24%a1. 

Lee et al. 

2004 
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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% NH4, -54% NO3, 38% TP, and 

-8% PO4

Mankin and 

Ikenberry 

2004 

UK Farm Constructed 

wetland 

Treating liquid swine manure after soil infiltration 

removed 94% of NH3-N and NH4-N, 95% of 

NO3-N, and 84% of Ttotal P. 

Prantner et 

al. 2001 

MD Farm Constructed 

wetland 

Treating dairy wastewater Ttotal N reduced 

98%, ammonia 56%, Ttotal P 96%, ortho-P 

84%, SSsuspended 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 NH3-N treating agricultural wastewater 

Smith et al. 

2006 

Nova 

Scotia 

Farm Constructed 

wetland 

Load reductions of 54% Ttotal 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 pollutants; the contributions of microbial mechanisms increased 

with the duration of wetland use. Water hyacinth made only a minimal contribution to the removal of nutrients.

1 

2 Other biological treatment 

3 A multiple-pond system (APS) treating dairy milking parlour effluent in New Zealand produced 

4 effluent with 50–60 percent less BOD, TSS, TKN and ammonia-N than equivalently sized two--

5 pond systems with medians of 43, 87, 61, and 39 mg/L, respectively. TTotal P was reduced by 

6 70 70 percent to 19 mg/L. E.scherichia coli were reduced in the APS by two orders of magnitude

7 to 918 MPN/100 mLml (Bolan et al. 2009). 

8 In Morocco, El Hafiane et al. (2003) reported averaged removals of 70 percent for N and 40 40

9 percent for P in a high-rate algal pond treating wastewater. Water hyacinth ponds were reported 

10 to achieve ~50 percent removal of applied organic loads (COD, BOD, TN, and TP) from swine 

11 waste in Brazil (Costa et al. 2000). 

12 In Scotland, an algal-based bioreactor achieved sustained nutrient removal efficiencies (up to 

13 99 99 percent and 86 percent for NH4-N and PO4-P, respectively) from swine wastewater while 

14 total COD was removed up to 75 percent (Gonzalez et al. 2008). Lu et al. (2008) augmented a 

15 wetland treating duck waste in China with water hyacinth and reported removal of 64 percent of 

16 COD, 22 22 percent TNtotal N, and 23 percent Ttotal P loads. The hyacinth was harvested and 

17 recycled as duck feed. 

18 Anaerobically digested dairy manure effluent was treated with algal turf scrubber raceways in 

19 Maryland (Mulbry et al. 2008). Removal rates of 70–-90 percent of input N and P were achieved 
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Chapter 2. Agriculture 2-42 

at loading rates below 1 g TN, 0.15 g TP /m21 /d; N and P removal rates decreased to 50–-80 

2 percent at higher loading rates. 

3 An entrapped mixed microbial cells (EMMC) process was used to investigate the simultaneous 

4 removal of carbon and Nnitrogen from dilute swine wastewater in Hawaii (Yang, Chen et al. 

5 2003). COD removal efficiencies were 84 percent and Ttotal P removal efficiencies of 98 

6 percent were achieved. 

7 Table 2-11. Summary of reported practice effects resulting from other biological treatment.

Location 

Study 

type Practice Practice effects Source 

Numerous Review Membrane 

filtration 

Ultrafiltration (UF) (0.01 μm) of manure: up to 

100% removal of coliform and SS, 87% P 

reduction, no effect on soluble COD; lower 

efficiency from microfiltration (0.2μm: 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 

recoveryarecove

ry1

Achieved > 90% reduction in ammonia content in 

swine waste 

Loeffler and 

van Kempen 

2003 

Korea Farm Chemical 

precipitationbpre

cipitation2

Up to 90% removalRemoval of P from swine 

waste 

Choi et al. 

2008 

Notes:

a.Footnotes:

1

 Ammonia recovery using a metal ion treated resin bed 

b. Struvite2struvite and hydroxyapatite 

8 

9 Air quality 

10 Ammonia, dust, and odors associated with animal agriculture—especially on large facilities—

11 can be important local air pollutants. For example, Melse and Timmerman (2009) reported that N 

12 emissions in exhaust air from pig houses in the Netherlands can represent as much as 25 percent 

13 of the Ttotal N excretion by the animals. Airborne ammonia can also become a significant water 

14 pollutant when deposited in local waterbodies. Indoor air quality can affect animal health as well, 

15 especially at large poultry facilities. Animal production facilities can be important producers of 

16 GHSsgreenhouse gasses (van der Meer 2008). 
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Chapter 2. Agriculture 2-43 

1 Ullman et al. (2004) reviewed abatement technologies available to reduce atmospheric emissions 

2 from animal production facilities and summarized the following: 

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

4 15–45 percent. 

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

6 • Biofilters can exhibit 90 percent or better reductions of odor-causing chemicals such as 

7 hydrogen sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide. 

8 • Ionization systems can reduce dust concentrations 68–92 percent. 

9 • Indoor ozone systems can decrease total dust concentrations by 60 percent and ammonia 

10 levels by 58 percent compared to similar buildings without ozone treatment. 

11 The authors added that poultry litter amendments such as sodium bisulfate and alum can reduce 

12 odor and ammonia emissions and natural windbreaks can provide an entrapment mechanism for 

13 odorous compounds that require minimal maintenance. Windbreaks placed downwind of exhaust 

14 fans and litter storage areas canmay provide an economical management practice for broiler 

15 producers when used in conjunction with other air-cleaning practices. 

16 In Kentucky, Singh et al. (2009) reported that adding a commercially available urease inhibitor 

17 to poultry litter resulted in a significant reduction in equilibrium ammonia concentration over 

18 time by disrupting the enzymatic degradation of uric acid. 

19 Melse and Timmerman (2009) reported average ammonia removal efficiencies of 70–-96 percent 

20 for farm-scale operated acid scrubbers on swine facilities in the Netherlands. Reported average 

21 removal efficiency for odor was only 31 percent and showed a large variation. Multi-pollutant 

22 scrubbers removed an average of 66 percent of ammonia, 42 percent of odor, 50 percent of PM10, 

23 and 57 percent of PM2.5. 

24 Adrizal et al. (2008) evaluated the potential of trees planted around Pennsylvania commercial 

25 poultry farms to trap ammonia and dust or particulate matter. Results indicated that poplar, 

26 hybrid willow, and Streamco willow are appropriate species to absorb poultry house aerial NH3-

27 N, whereas spruce and hybrid willow are effective traps for dust and its associated odors. 

28 Koenig et al. (2005) reported that aluminum sulfate and process controls such as moisture 

29 content, carbon source and particle size have potential to reduce ammonia loss from poultry 

30 manure composted inside high-rise layer structures. Although both low moisture and temperature 

31 reduced NH3 capture, managing temperature and moisture to achieve low NH3 would adversely 

32 affectimpact microbial activity and other desired benefits of composting. 

33 In a Texas laboratory study, Shi et al. (2001) evaluated amendments for reducing ammonia 

34 emissions from open-lot beef cattle feedlots and found that cumulative ammonia emissions after 

35 21 days compared to the untreated control were: 2–8 percent for alum, 22–29 percent for CaCl2, 

36 32–40 percent for humate, 34–36 percent for a urease-inhibitor NBPT, and 68–74 percent for a 

37 commercial product. 

38 In North Carolina, Szogi and Vanotti (2007) demonstrated that solid-liquid separation 

39 technologies can substantially reduce ammonia emissions from anaerobic swine lagoons. 
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Chapter 2. Agriculture 2-44 

1 Ammonia emissions from a lagoon with solid-liquid separation had 73 percent lower ammonia 

2 emissions compared to an anaerobic lagoon. 

3 Replacing Replacement of swine waste lagoon technology with cleaner aerobic technology in 

4 North Carolina reduced GHGgreenhouse gas emissions 96.9 percent—from 4,972 tonnes to 153 

5 tonnes of carbon dioxide equivalents (CO2-eq)/yr (Vanotti et al. 2008). 
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Chapter 2. Agriculture 2-45 

1 Table 2-12. Summary of reported practice effects for air quality issues.

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% PM10 removal, and 57% PM2.5

Melse and 

Timmerman 

2009 

PA Farm Tree 

windbreaks 

Poplar, hybrid willow, and Streamco willow 

absorb poultry house aerial NH3-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 CaCl2, 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 GHGrReduced greenhouse gas

emissions 96.9%, from 4,972 t to 153 t of 

carbon dioxide equivalents (CO2-eq)/yr 

Vanotti et al. 

2008 

2 Practice Costs 

3 Systematic cost data for most practices are rarely given in the scientific literature; better cost data 

4 mightmay be available on a state or county basis from producers, groups, or agencies funding or 

5 managing implementation. Among reported cost data, there is a lack of consistency in unit costs 

6 (e.g., $/cow, $/kg P removed, or $/L of waste treated) that sometimes makes comparison among 

7 practices difficult. Cost figures are reported in dollars for the year given by the authors. 

8 In laboratory studies, Jones and Brown (2000) estimated chemical cost (2008 dollars) for 

9 combinations of alum and poylacrylamide (PAM) of $73–-198/kg orthophosphate-P (ortho-P)

10 removed from dairy wastewater. For supplementary precipitation of soluble P in the treatment of 

11 dairy manure by mechanical separation, Oh et al. (2005) estimated costs for alum and polymer 

12 addition of about $2.88 per 1,000 L of treated manure slurry. 
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Chapter 2. Agriculture 2-46 

1 Moore et al. (2000) found that alum applications to poultry litter was cost-effective, with a 

2 benefit/cost ratio of 1.96 due partly from to heavier birds, better feed conversion, and lower 

3 energy use to vent ammonia from the houses. 

4 In a cost analysis of anaerobic digestion and methane production, Garrison and Richard (2005) 

5 noted that the economic feasibility of the energy conversion technology varies widely with scale, 

6 with significant advantages for larger facilities. FarrowFor swine operations, farrow-to-finish and 

7 finishing swine operations needed more than 20,000 head and 5,000 head, respectively, to be 

8 economically feasible. Dairy operations in the Midwestern United States.S. dairy operations hold 

9 considerably more economic promise, with feasible herd counts in the 150- to 350-head range 

10 for electricity prices of $0.13/kWh (2008 dollars). Results indicate that increased energy prices 

11 and financial assistance will be needed to encourage significant numbers of facilities to recover 

12 energy from manure. 

13 Brodie et al. (2000) studied technologies to manufacture compost from poultry litter and reported 

14 that screened compost was produced at an operational cost of $37 (2008 dollars) while 

15 unscreened compost could be produced for about $25 per ton of compost. A production scheme 

16 where poultry litter is static pile composted on farms for later transport to regional processing 

17 centers appears feasible. 

18 Kemper and Goodwin (2009) reported that in composting poultry litter and eggshell waste into a 

19 marketable soil amendment, compost could be produced at an average cost of $17.48 to 

20 $20.09/ton for small-scale and large-scale systems, respectively. The cost for disposing of 

21 eggshell waste in landfills was $25/ton. 

22 In a study of using filamentous green algae grown in outdoor raceways to treat dairy manure 

23 effluent, Mulbry et al. (2008) projected annual operational costs of $780 per cow. For 

24 comparison, the operational costs of $11 per kg N removed are well below the costs cited for 

25 upgrading existing water treatment plants. 

26 Shi et al. (2001) calculated the costs of six amendments for reducing ammonia emissions from 

27 open-lot beef cattle feedlots, ranging from $0.15 to $6.74 (2008 dollars) per application per head. 

28 Only one treatment had a benefit/cost ratio greater than 1.0. Results suggest that amendments can 

29 reduce ammonia emissions from open feedlots, but the costs mightmay be prohibitive. 

30 Vanotti et al. (2008) analyzed GHGgreenhouse gas emission reductions from implementing

31 implementation of aerobic technology on swine farms in North Carolina and estimated emission 

32 reductions of 4,776.6 tonnes CO2-eq per year or 1.10 tonnes CO2-eq/head per year. The dollar 

33 value from implementation was US $19,106/year using current Chicago Climate Exchange

34 trading values of US $4/t CO2. ThatThis translates into a direct economic benefit to the producer 

35 of US $1.75 per finished pig. The authors suggestsuggested that GHG emission reductions and 

36 credits can help compensate for the higher installation cost of cleaner aerobic technologies and 

37 facilitate producer adoption of environmentally superior technologies to replace current 

38 anaerobic lagoons. 

39 In studies of poultry litter amendments to reduce odor and ammonia volatilization, Ullman et al. 

40 (2004) found that sodium bisulfate and alum treatments ranged in price from $220 to $460 per 

ton (dollar year unknown), resulting in a cost of $11 to $16 for 92.9 m2 (1,000 ft241 ) at 
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Chapter 2. Agriculture 2-47 

1 recommended application rates. Another cost benefit analysis showed that ammonia reduction by 

2 ventilation during cold periods would cost $3,800 per flock (19,000 birds weighing 4 lb each). 
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Chapter 2. Agriculture 2-48 

1 3 Implementation Measures and Practices for In-field 

2 Control 

3 The best approach to minimize nutrient transport to local waters depends upon whether the 

4 nutrient is in the dissolved phase or is attached to soil particles. For dissolved nutrients, effective 

5 management includes source reduction and reduction of water runoff or leaching. Erosion and 

6 sediment transport controls are necessary to reduce transport of nutrients attached to soil 

7 particles. Practices that focus on controlling the transport of smaller soil particle sizes (e.g., clays 

8 and silts) are most effective because theythese are the soil fractions that transport the greatest

9 share of adsorbed nutrients. 

10 3.1 Field Nutrient Management 

11 Strategies for in-field control on row crop land focus on managing the form, application method, 

12 and timing of waste and nutrient applications and on controlling soil conditions to reduce the 

13 potential for runoff of nutrients. Pasture management strategies address managing animal 

14 stocking rates and maintaining vigorous vegetation to provide for soil stability and nutrient 

15 recycling. 

Implementation Measure: Manage nutrient applications to row crop land to minimize nutrients 

available for runoff. In doing so, apply manure and chemical fertilizer application during the 

growing season only, do not apply any manure to frozen ground, inject or otherwise incorporate 

all manure or organic fertilizer to minimize the available dissolved P and volatilized N, and do 

not apply nutrients to HELs.

16 Implementation Measure: Manage nutrient applications to row crop land to minimize 

17 nutrients available for runoff. In doing so, apply manure and chemical fertilizer 

18 application only during the growing season, do not apply any manure to frozen ground, 

19 inject or otherwise incorporate all manure or organic fertilizer to minimize the available 

20 dissolved P and volatilized N, and do not apply nutrients to HELs.

21 In many row crop areas, nutrient imports in feed and fertilizers exceed exports in crops 

22 produced; thatthis imbalance often exists at both the individual field and the watershed level 

23 (Beegle, 2000). In such circumstances, nutrients canmay accumulate in soils from over24 application of fertilizer or animal waste relative to crop need. Excessive soil nutrient levels have 

25 been linked to high P losses in runoff and leaching losses of N, especially in areas of animal26 based agriculture 

27 Nutrient management is an important tool to match nutrient inputs more closely to crop needs. 

28 The USDA-NRCS Nutrient Management Practice (NRCS Practice Code 590) generally defines 

29 nutrient management as “managing the amount, source, placement, form and timing of the 

30 application of nutrients and soil amendments.” The Nutrient Management Practice canmay be 

31 applied for a number of purposes: 

32 • To budget and supply nutrients for plant production;
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Chapter 2. Agriculture 2-49 

1 • To properly useutilize manure and organic byproducts or biosolids as a plant nutrient 

2 source;

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

4 resources 

5 • To protect air quality by reducing Nnitrogen emissions and the formation of atmospheric 

6 particulates; and

7 • To maintain or improve the physical, chemical, and biological condition of soil 

8 This section presents information concerning several management practices to manage nutrients 

9 on cropland to reduce nutrient losses: 

10 • Waste and fertilizer form—selecting selection of the form of nutrients applied to 

11 cropland to reduce runoff or leaching losses;

12 • Application methods and timing—selecting selection of the method and/or timing (or 

13 both) of manure or fertilizer application to cropland to support crop growth and reduce 

14 runoff or leaching losses;

15 • Nutrient management planning—preparing and implementingpreparation and 

16 implementation of a comprehensive plan to manage nutrients from all sources to provide 

17 for crop growth while minimizing runoff and leaching losses of nutrients; and

18 • Soil and manure amendment—treatingtreatment of soils or manure to reduce the 

19 availability or mobility of nutrients.

20 Practice Effectiveness 

21 Waste and Fertilizer Form and Rate 

22 Chien et al. (2009) reviewed recent developments of fertilizer production and use that improve 

23 nutrient efficiency and minimize environmental impact. Improving N nutrient efficiency includes 

24 using the following:

25 use of : 

26 1.• Controlled-release coated urea products,

27 2.• Slow-release urea-aldehyde polymer products,

28 3.• Urea supergranules for deep placement,

29 4.• Nitrification inhibitors (NIs) to reduce nitrate leaching and denitrification, 5

30 5.• Urease inhibitors to reduce ammonia volatilization from urea, and

31 6.• Ammonium sulfate to enhance N efficiency of urea.

32 Improving the efficiency of conventional P fertilizers includes using the followinguse of : 

33 (1)• Coated, water-soluble P fertilizers,

34 (2)• Urea supergranules containing P and K nutrients, and 3

35 (3)• Fluid P fertilizers.
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1 Use of nonconventional P fertilizers includes the following: 

2 (1)• Phosphate rock (PR) for direct application, 

3 (2)• A mixture of PR and water-soluble P sources,

4 (3)• Calcined nonapatite PR for direct application, and

5 (4)• Nonconventional acidulated P fertilizers containing water-insoluble but citrate6 soluble P compounds. The use of these nonconventional fertilizers may result in an 

7 increased relative economic benefit with respect to the use of conventional fertilizers in 

8 terms of saving fertilizer cost, enhancing nutrient efficiency, or increasing crop yield.

9 Slow-release fertilizer (SRF) and controlled-release fertilizer (CRFCRY) materials mightmay be 

10 beneficial to improve nutrient uptake efficiency and reduce the leaching potential of excess 

11 nutrients (Morgan et al. 2009). ThoseThese considerations are particularly important for crops 

12 grown on sandy soils with relatively low nutrient- and water- holding capacities 

13 In New Zealand, Sojka (2009) compared the efficacy of matrix-based fertilizers (MBFs) 

14 formulated to reduce nitrate, ammonium, and total phosphorus (TP) leaching with conventional 

15 SRFsslow-release fertilizers (SRF)), and an unfertilized control. SRF leachate contained higher 

16 amounts of nitrate, ammonium, and TP than leachate from all other fertilizers. There were no 

17 consistent differences in the amount of nitrate, ammonium, and TP in the MBF leachates 

18 compared to the control leachate.

19 Penn et al. (2004) tested the effects of phytase enzyme and HAP corn supplemented diets on 

20 runoff P concentrations from VirginiaVA pasture soils receiving surface applications of turkey 

21 manure. The alternative diets caused a decrease in manure total and water-soluble P compared P

22 with the standard diet. Runoff dissolved P concentrations were significantly higher from HAP 

23 manure-amended soils while dissolved P losses from other manure treatments were not 

24 significantly different from each other. 

25 In a laboratory study, Loria and Sawyer (2005) compared the effect of raw and digested liquid 

26 swine manure application on soil test P and inorganic N. Raw and digested manure produced the 

27 same NH4-N disappearance, NO3-N formation, net inorganic N, and an increase in soil test P. 

28 Routine soil test P methods estimated similar P recovery with both manure sources. 

29 In Iowa, Loria et al. (2007) found no difference between raw swine manure and manure digested 

30 for biogas as a source of N for plant use in the year of application or in the residual year; 

31 equivalence to fertilizer N was the same with both raw and digested swine manure. 

32 In Georgia, Risse and Gilley (2000) reported that runoff was reduced from 1 to 68 percent, and 

33 soil loss decreased from 13 to 77 percent for locations on which manure was added annually. 

34 Measured runoff and soil loss values were found to be strongly influenced by manure application 

35 rates. Regression equations were developed relating reductions in runoff and soil loss to manure 

36 application rates. 

37 In Colorado, Shoji et al. (1999) conducted field trials on CRFs and an a nitrification inhibitor 

38 (NI) to show their potential to increase NUE. TTotal N fertilizer losses averaged 15 and 10 

39 percent in the NI and urea treatments, respectively. On the other hand, those from the CRF 
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1 treatment averaged only 1.9 percent, indicating that CRF showed the highest potential to increase 

2 N use efficiency. 

3 King and Torbert (2007) reported an OH plot study was designed to compare temporal losses of 

4 NO3-N and NH4-N from three SRFsslow-release fertilizers (sulphur-coated urea, composted 

5 dairy manure, and poultry litter) and one fast-release fertilizer (ammonium nitrate) applied to 

6 Bermudabermuda grass turf. Cumulative NO3-N loss from plots receiving application of the 

7 manufactured (NH4NO3 and sulphur-coated urea) products was significantly greater than the 

8 measured losses from plots receiving application of composted dairy manure and poultry litter. 

9 The cumulative NO3-N recovered in the runoff expressed as a proportion of applied N was 0.37 

10 for ammonium nitrate, 0.25 for sulphur-coated urea, 0.10 for composted dairy manure, and 0.07 

11 for poultry litter. 

12 Table 2-13. Summary of reported practice effects resulting from management of waste and 

13 fertilizer form and rate.

Location

Study 

type Practice Practice effects Source 

New 

Zealand 

Plot Fertilizer 

formulation 

Leachate from conventional SRFsslow-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 

NH4-N disappearance, NO3-N formation, net 

inorganic N, and an increase in soil test P. Routine 

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, 

NIsControlle

d release 

fertilizer, 

nitrification 

inhibitors

TTotal N fertilizer losses averaged 15% and 10% 

in the NInitrification inhibitor and urea treatments, 

respectively. N losses from the controlled release 

fertilizer treatment averaged only 1.9% 

Shoji et al. 

1999 
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OH Plot SRFsSlow 

release 

fertilizers

Cumulative NO3-N loss from plots receiving 

application of manufactured (NH4NO3 and sulphurcoated urea) products was significantly greater 

than the measured losses from plots receiving 

application of composted dairy manure and poultry 

litter. The cumulative NO3-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 

1 Nutrient Application Methods and Timing 

2 In soil column and field studies in New York, Geohring et al. (2001) reported that high P 

3 concentrations observed in tile drain effluent soon after dairy manure application can be 

4 attributed to macropore transport processes. Plowing-in manure apparently disturbs these 

5 macropores and promotes matrix flow, resulting in greatly reduced P concentrations in the 

6 drainage effluent. 

7 In New York, Lewis and Makarewicz (2009) reported significant decreases in winter 

8 concentrations of Ttotal P, soluble P, TKN, and NO3-N but not TSS following cessation of 

9 winter dairy manure application to cropland. 

10 Chen and Samson (2002) investigated the effects of fertilizer source and manure application 

11 timing, rate, and method on soil nutrient concentrations, corn grain yields, and groundwater 

12 nitrate concentrations in Ontario, Canada. In general, higher NO3-N concentrations were 

13 observed in those plots where Nnitrogen sources had been applied shortly before soil sampling. 

14 Trends of residual NO3-N concentrations varied among experiments, and results were 

15 inconclusive. Two-fold higher P concentrations were observed in the manured plots than in the 

16 inorganically fertilized plots as a result of higher P2O5 inputs from swine manure. 

17 In Kansas plots, Reiman et al. (2009) tested the effectimpact of manure placement depth on corn 

18 and soybean yield and N retention in soil. The net effectimpact of placement on Ttotal N was 

19 that deep manure injection treatments had 31–59 more kg N/ha than the shallow injection 

20 treatment 12 to 30 months after application. Higher corn yield in the deep- injected treatment 

21 was attributed to increased N use efficiency. Higher inorganic N amounts in the deep injection 

22 treatment were attributed to reduced N losses through ammonia volatilization, leaching, or 

23 denitrification. 

24 Ali et al. (2007) tested simplified surface irrigation of dairy farm effluents in Quebec, Canada,

25 and reported that seepage losses represented less than 1 percent of the total volume of effluents 

26 applied, nutrients and bacteria applied were lost in subsurface drainage, implying a treatment 

27 efficiency of > 99 percent compared to conventional land spreading. 

28 In an Ontario, Canada, plot study, Coelho et al. (2006) determined the effects of rate and method 

29 of sidedress application of liquid swine manure on N recovery by corn using in-row injection or 

30 topdressing to sidedress manure. Coelho et al. (2006) measured grain N uptake and NO3-N in 

31 drainage water, stalks, and topsoil postharvest. Apparent recovery of manure Ttotal N was 

32 greater with injection (59 percent) than topdress (41percent) and transport of N to groundwater-
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Chapter 2. Agriculture 2-53 

1 and surface waterwaters was minimized when sidedressed at or below rates for optimal yield. 

2 When injected N exceeded crop demand, NO3-N increased to over 10 mg/kg in topsoil, 20 mg/L 

3 in drainage water, and to excessive (3.6 g/kg) levels in stalks. 

4 Drainage NO3-N concentration and load increased linearly by 0.69 mg NO3-N/L and 4.6 kg NO3-

5 N/ha, respectively, for each 10 kg N/ha applied over the minimum of 275 kg N/ha in trials of 

6 swine waste application to corn in Spain (Dauden et al.2004). An increase in irrigation efficiency 

7 did not induce a significant increase of leachate concentration and the amount of nitrate leached 

8 decreased about 65 percent. Application of low manure doses before sowing complemented with 

9 sidedressing N application and good irrigation management are the key factors to reduce nitrate 

10 contamination of water courses. 

11 Soil injection of swine manure on soybeans in Illinois compared with surface application 

12 resulted in runoff concentration decreases of 93, 82, and 94 percent, and load decreases of 99, 

13 94, and 99 percent for dissolved P, Ttotal P and algal-available P, respectively (Daverede et al. 

14 2004). Incorporating Incorporation of inorganic P fertilizer also reduced P concentration in 

15 runoff significantly. Runoff P concentration and load from incorporated amendments did not 

16 differ from the control. 

17 Allen and Mallarino (2008) assessed total runoff P, bioavailable P, and dissolved P 

18 concentrations and loads in surface runoff after liquid swine manure application with or without 

19 incorporation into soil and different timing of rainfall in IllinoisIL. For events 24 hours after 

20 application, P concentrations were 2 to 5 times higher for nonincorporated manure than for 

21 incorporated manure; P loads were 3.8 to 7.7, and 3.6 times higher. A 10- to 16-day rainfall 

22 delay resulted in P concentrations that were ~3 times lower than for 24-hour events across all 

23 nonincorporated P rates. 

24 Andraski et al. (2003) investigated the effects of manure history and tillage on P levels in runoff 

25 from continuous corn in Wisconsin. Soil P levels increased with the frequency of manure 

26 applications and P stratification was greater near the surface in no-till than in chisel plow. In 

27 chisel plow, soil test P level was linearly related to dissolved P and bioavailable P loads in 

28 runoff. In no-till, P loads were reduced by an average of 57 percent for dissolved P, 70 percent 

29 for bioavailable P, and 91 percent for Ttotal P compared with chisel plow. 

30 In an Iowa plot study, Bakhsh et al. (2009) determined the effects of swine manure application to 

31 corn and soybeans on NO3-N concentrations in subsurface drainage water and corn-soybean 

32 yields. Average flow-weighted NO3-N concentrations and leaching losses increased by > 50 

33 percent when manure was applied to both corn and soybean compared to manure application to 

34 corn only, while yield differences were less than 4 percent. ThoseThese results suggest that fall 

35 manure application to both corn and soybean is likely to increase NO3-N leaching to shallow 

36 groundwater without resulting in significant yield benefits. 

37 Kleinman et al. (2009) evaluated losses of P in sub-surface and surface flow as a function of 

38 dairy manure application to no-till soils in Pennsylvania. Incorporation of manure by tillage 

39 lowered P loss in leachate relative to broadcast application because of due to the destruction of 

40 preferential flow pathways. In contrast, rainfall simulations on runoff plots showed that Ttotal P 

41 losses in surface runoff differed significantly by soil but not by application method. Results 
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1 confirm the near-term benefits of incorporating manure by tillage to protect groundwater quality,

2 but suggest that for surface water quality, avoiding soils prone to runoff is more important. 

3 Warren et al. (2008) compared surface broadcast litter application and subsurface litter banding 

4 on grassland in Alabama. Subsurface band applications resulted in forage yields equivalent to 

5 those achieved by conventional broadcast litter applications and did not significantly alter the 

6 Mehlich 3 extractable nutrient content of soils collected at a depth of 0 to 15 cm. 

7 In Arkansas, Pote et al. (2003) determined effects of poultry litter incorporation into Bermuda

8 bermudagrass and mixed forage plots on quantity and quality of runoff water. Nutrient 

9 concentrations and mass losses in runoff from incorporated litter were 80–95 percent less than in 

10 runoff from surface-applied litter. Litter-incorporated soils had greater rain infiltration rates, 

11 water-holding capacities, and sediment retention than soils receiving surface-applied litter. In a 

12 subsequent study, Pote et al. (2009) confirmed that fully mechanized litter subsurface banding 

13 increased forage yield while decreasing nutrient N and P loss in runoff by at least 90 percent 

14 compared to surface-broadcast litter. 

15 Sistani et al. (2009) evaluated the effect of broiler litter application method and the runoff timing 

16 on nutrient and E. coli losses from Alabama perennial grassland. TP, inorganic N, and E. coli

17 concentrations in runoff from broadcast litter application were all significantly greater than from 

18 subsurface litter banding. TP losses from broadcast litter applications averaged 6.8 times greater 

19 than those from subsurface litter applications. Average NO3-N and TSS losses from subsurface 

20 banding were reduced by 64 percent and 68 percent, respectively, compared to the broadcast 

21 method. 

22 In soil columns, Guo et al. (2009) evaluated nutrient release dynamics of Delmarva poultry litter 

23 under local weather conditions. Release of most nutrients occurred principally in the first 100 

24 days, but for P, release would last for years. The nutrient supply capacity of surface-applied 

25 Delmarva poultry litter was predicted at 10.9 kg N/Mg and 6.5 kg P/Mg. The results suggest that 

26 Delmarva poultry litter should be applied to conservation tillage systems at 6.6 Mg/ha that would 

27 furnish 25 kg P/ha and 63 kg N/ha to seasonal crops. In repeated annual applications, the rate 

28 should be reduced to 5.2 Mg/ha, with supplemental N fertilization to meet crop N requirements. 

29 Kaiser et al. (2009) assessed P loss immediately after poultry manure application to soybean 

30 residue with and without tillage at eight IowaIA fields. Non-incorporated manure consistently 

31 increased concentrations of all runoff P fractions in five sites. On average manure increased 

32 dissolved P, bioavailable P, and TPtotal P 32, 23, and 12 times, respectively, over the control. 

33 Tillage to incorporate manure reduced dissolved P, bioavailable P, and Ttotal P by 88, 89, and 77 

34 percent on average, respectively. 

35 In a Georgia plot study, Franklin et al. (2006) reported that soil aeration reduced runoff volume 

36 by 27 percent in the first runoff event but the effect disappeared after one1 month; aeration did 

37 not affect the mass losses of dissolved reactive P (DRP), TKN, or NH4-N from plots fertilized 

38 with either inorganic fertilizer or poultry litter.

39 Franklin et al. (2007) evaluated the effects of slit aeration on runoff volume and P losses from 

40 fescue fertilized with broiler litter in GeorgiaGA. In the field with mostly well-drained soils, 

41 grassland aeration reduced surface runoff volume and mass losses of DRdissolved reactive 
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Chapter 2. Agriculture 2-55 

1 dissolved P in runoff by 35 percent. However, on poorly drained soils, grassland aeration 

2 increased runoff volume and mass losses of dissolved and TPtotal P. 

3 Butler et al. (2008a) evaluated the effects of three aeration treatments on export of TSS and P 

4 from grassland plots receiving broiler litter and dairy slurry in GeorgiaGA. Core aeration 

5 reduced export of Ttotal P by 55 percent, dissolved P by 61 percent, and bioavailable P 54 

6 percent plots with applied broiler litter as compared with the control. Core and no-till disk 

7 aeration also showed potential for reducing P export from applied dairy slurry. 

8 In British Columbia, Canada, van Vliet et al. (2006) studied the effect of mechanically aerating 

9 grassland before liquid manure application in on surface runoff and transport of nutrients and 

10 solids. Annual runoff amounts were reduced by 47–81 percent, suspended and volatile solid 

11 loads by 48–69 percent and 42–83 percent, respectively, TKN loads by 56–81 percent, and Ttotal 

12 P loads by 25–75 percent. Loads of the soluble nutrient NH4-N, DRdissolved reactive P, and K 

13 were reduced by 41–83 percent. 

14 Table 2-14. Summary of reported practice effects resulting from management of nutrient 

15 application methods and timing.

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 

Ttotal 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 NO3-N concentrations observed in plots 

where N sources applied shortly before soil 

sampling. Trends of residual NO3-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 higher 

P2O5 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. 

2007 
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Chapter 2. Agriculture 2-56 

Location 

Study 

type Practice Practice effects Source 

Ontario, 

Canada 

Plot Liquid 

manure 

injection 

Apparent recovery of manure Ttotal 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, NO3-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 NO3-N concentration and load increased 

linearly by 0.69 mg NO3-N/L and 4.6 kg NO3-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-hourshr 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 Ttotal P 

compared with chisel plow 

Andraski et 

al. 2003 

IA Plot Manure 

application 

timing 

NO3-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 than 

4%. Fall manure application to both corn and 

soybean is likely to increase NO3-N leaching to 

shallow groundwater without resulting in significant 

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 fromdue to the destruction of 

preferential flow pathways; Ttotal P losses in 

surface runoff differed significantly by soil but not 

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. 

2008 
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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 than 

in 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 NO3-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 for 

years. 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 sites; 

on average manure increased dissolved P, 

bioavailable P, and TPtotal P 32, 23, and 12 times, 

respectively, over the control. Tillage to incorporate 

manure reduced dissolved P, bioavailable P, and 

Ttotal 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

one1 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 

DRdissolved reactive dissolved P in runoff by 35%. 

However, on poorly drained soils, grassland 

aeration increased runoff volume and mass losses 

of dissolved and TPtotal P

Franklin et al. 

2007 

GA Plots Soil aeration Core aeration reduced Ttotal 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.

2008a 
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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 Ttotal P loads by 25–75%. 

Loads of the soluble nutrient NH4-N, DRdissolved 

reactive P, and K were reduced by 41- 83%. 

van Vliet et 

al. 2006 

1 

Implementation Measure: Control soil conditions by using soil amendments to influence P 

bound to soil.

2 Implementation Measure: Control soil conditions by using soil amendments to influence P 

3 bound to soil. 

4 Because runoff losses of P are strongly influenced by the quantity and form of P in the soil 

5 (Sharpley 1995;, Pote et al. 1996), reducing P runoff from row crop land canmay be 

6 accomplished by influencing soil test P levels through soil amendments that change the 

7 availability of P and through nutrient management planning. 

8 Practice Effectiveness 

9 Soil and Manure Amendment 

10 In Arkansas plots, Haustein et al. (2000) surface application of treatment residuals and HiClay 

11 Alumina to soil plots high in P decreased Mehlich 3 soil test P levels and the two highest rates of 

12 WTR water treatment residuals decreased runoff P levels below those of the control plots..

13 From a Texas field experiment, Brauer et al. (2005) reported that annual additions of gypsum at 

14 5.0 Mg/ha significantly reduced soil-dissolved P, although soil amendment did not affect Bray-1 

15 P values. Elliott et al. (2002) conducted laboratory and greenhouse studies of the ability of WTR

16 water treatment residuals to alter P solubility and leaching in a Texas soil amended with 

17 biosolids and triple superphosphate. Without residual amendment, 21 percent of soluble P and 11 

18 percent of biosolids Ttotal P leached over 4 months. With co-applied residuals, soluble P losses 

19 were reduced to < 1–3.5 percent of applied P. Amendment with residuals retarded downward P 

20 flux such that leachate P was not statistically different than for control (soil only) columns. 

21 In North Carolina, Novak and Watts (2004) conducted laboratory experiments to determine if 

22 WTR water treatment residuals mixed into soils could significantly increase their P sorption 

23 capacities. Mixing residuals into soils increased their P-max values several-fold (between 1.7 to 

24 8.5 mg P/g) relative to soils with no WTR addition. The authors suggested that WTR 

25 incorporation into sandy soils has the potential to be a new chemical-based best management 

26 practice (BMP) for reducing off-site P transport. 

27 Novak and Watts (2005) evaluated the ability of alum-based WTR water treatment residuals to 

28 reduce soil P concentrations in three P-enriched North Carolina Coastal Plain soils. Incorporating

29 Incorporation of residuals into the soils caused a near linear and significant reduction in soil P 
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Chapter 2. Agriculture 2-59 

1 concentrations. In two soils, 6 percent WTR application caused a soil Melich 3 P concentration 

2 decrease to below the soil P threshold. 

3 Adding WTRAddition of water treatment residuals to Oklahoma soil plots treated with poultry 

4 litter reduced runoff P by from 14–85 percent (Dayton et al. 2003). Reductions in runoff P were 

5 strongly correlated with P-max and Al-ox. Performance of treatment residuals as a P sorbent to 

6 reduce runoff P from manured land can be estimated from their P-max or Al-ox content. 

7 In a Connecticut laboratory study, Hyde and Morris (2000) reported that WTRwater treatment 

8 residuals significantly reduced Mehlich 3 P concentrations when added to soils. Adding residuals 

9 to soils reduced soil P concentrations by 23–64 percent, depending on how the residuals were 

10 dewatered. 

11 Adler and Sibrell (2003) tested the use of flocculants (flocs) resulting from neutralizing acid 

12 mine drainage (AMD) (as a possible low-cost amendment to reduce the loss of soluble P from 

13 agricultural fields and animal wastewater) in West Virginia. About 70 percent of water14 extractable P was sequestered by the floc when applied to agricultural soils at a rate of 20 g 

15 floc/kg soil, whereas plant-available P decreased by 30 percent. Under anaerobic conditions 

16 simulating manure storage basins, all AMD flocs reduced soluble P by greater than 95 percent. 

17 At two Michigan field sites with a history of heavy manure applications, amendment with 

18 WTRwater treatment residuals reduced water-soluble P concentration by > 60 percent as 

19 compared to the control plots, and the residuals-immobilized P remained stable 7.5 yryears after 

20 residuals application (Agyin-Birikorang et al. 2007). 

21 Staats et al. (2004) investigated the efficacy of alum-amended poultry litter in reducing P release 

22 from three Delaware Coastal Plain soils. Long-term desorption (25 days)) of the incubated 

23 material resulted in ~13 percent reductions in cumulative P desorbed when comparing soil 

24 treated with unamended poultry litter. In addition, the P release from the soil treated with alum25 amended litter was not significantly different from the control (soil alone). 

26 Zvomuya et al. (2006) tested the P-binding ability of various amendment materials in a 

27 laboratory soil incubation experiment. Lysimeter breakthrough tests using tertiary-treated potato28 processing wastewater showed that alum application reduced leachate TP and SRsoluble reactive 

29 P concentrations by 27 percent and 25 percent, respectively. 

30 Table 2-15. Summary of reported practice effects resulting from soil and manure amendment.

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 WTRwater 

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. 

2005 
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Chapter 2. Agriculture 2-60 

Location Study type Practice Practice effects Source 

TX Laboratory, 

greenhouse

WTRWater 

treatment 

residuals

Without residual amendment, 21% of soluble P 

and 11% of biosolids Ttotal 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 WTRWater 

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 WTRWater 

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 WTRWater 

treatment 

residuals

Addition of WTR water treatment residuals to OK 

soil plots treated with poultry litter reduced runoff 

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 WTRWater 

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 rate 

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 WTRWater 

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 SRsoluble 

reactive P concentrations by 27% and 25%, 

respectively 

Zvomuya et 

al. 2006 

1 Nutrient Application Planning 

2 In a Virginia field study, Maguire et al. (2008) investigated how changing nutrient management 

3 from an N to a P basis affected crop yields and soil properties in high P soils over a 7-year 
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Chapter 2. Agriculture 2-61 

1 period. After 7 years, Mehlich 1 P and water-soluble P were greatest in soils under the N-based 

2 treatments, smallest in the no-P treatment, and intermediate in the P-based treatments; there were 

3 no significant differences between inorganic fertilizer and poultry litter nutrient sources. The 

4 results show that soil test P can be decreased in high-P soils over a few years by changing from 

5 an N-based to a P-based nutrient management plan or stopping P applications without negatively 

6 affecting yields. 

7 In Quebec, Canada, Giroux and Royer (2007) measured the effect of three P fertilizer rates on 

8 crop yields and evolution of the soil test values, saturation and P solubility. Soil test P values 

9 decreased by 11–33 percent over 8 years, even at P application rates above crop removal. Annual 

10 rates of P saturation decrease were 1.087, 0.891 and 0.750 percent/yr respectively for the 0, 30, 

11 and 60 kg P2O5/ha fertilizer rates. The P saturation value of 13.1 percent of the Quebec 

12 regulation is achieved after 10 years for the 0 kg P2O5/ha rate 

13 In Texas, Choi et al. (2003) reported that 46–77 percent of the applied manure P was removed in 

14 a single turfgrass sod harvest. Total dissolved P concentrations in the runoff were directly related 

15 to P concentrations in the soil. A total of 3.8 percent of the applied P from composted dairy 

16 manure was lost in the surface runoff. 

17 From Texas plot studies, McFarland and Hauck (2004) reported that usinguse of only 

18 commercial N on soils with high extractable P levels decreased P loadings in edge-of-field runoff 

19 by > 40 percent. However, no notable changes in extractable soil P concentrations were observed 

20 after 5five years of monitoring because of due to drought conditions limiting forage uptake and 

21 removal. 

22 In a Texas study using an integrated economic and environmental modeling system across 

23 multiple ecoregions, Osei et al. (2008) suggested that edge-of-field Ttotal P losses can be 

24 reduced by about 0.8 kg/ha/year or 14 percent when manure applications are calibrated to supply 

25 all of the recommended crop P requirements from manure Ttotal P sources only, when compared 

26 to manure applications at the recommended crop N agronomic rate. 

27 Table 2-16. Summary of reported practice effects resulting from nutrient application planning.

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 be 

decreased in high-P soils by changing from an Nbased to a P-based nutrient management plan or 

stopping P applications without negatively affecting 

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 P2O5/ha fertilizer rates. The P 

saturation value of 13.1% of the Quebec regulation 

is achieved after 10 years for the 0 kg P2O5/ha rate

Giroux and 

Royer 2007 

TX Field Turfgrass sod 46% to 77% of the applied manure P removed in a Choi et al. 
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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 UsingUse of only commercial N on soils with high 

extractable P levels decreased P loadings in edgeof-field runoff by > 40%. 

McFarland 

and Hauck 

2004 

TX Model P-based 

manure 

management 

Edge-of-field Ttotal 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 

Ttotal P sources only, versusvs, manure 

applications at N agronomic rate. 

Osei et al. 

2008 

1 3.2 Sediment and Erosion Control 

2 Sediment loss is the result of erosion. It is the solid material, both mineral and organic, that is in

3 suspension, is being transported, or has been moved from its site of origin by wind, water, 

4 gravity, or ice. The types of erosion associated with agriculture that produce sediment are (1) ) 

5 sheet and rill erosion, (2) ephemeral and classic gully erosion, (3) wind erosion, and (4) ) 

6 streambank erosion. Soil erosion can be characterized as the transport of particles that are 

7 detached by rainfall, flowing water, or wind. Eroded soil is either redeposited on the same field 

8 or transported from the field in runoff or by wind.

9 The strategies for controlling erosion and sedimentation involve reducing soil detachment, 

10 reducing sediment transport, and trapping sediment before it reaches water. The first objective 

11 for both water and wind erosion is to keep soil on the field, and the easiest and often most 

12 effective strategy to accomplish this is to reduce soil detachment. Detachment occurs when water 

13 splashes onto the soil surface and dislodges soil particles, or when wind reaches sufficient 

14 velocity to dislodge soil particles on the surface.

15 Crop residues (e.g., straw) or living vegetative cover (e.g.., grasses) on the soil surface protect 

16 against detachment by intercepting and/or dissipating the energy of falling raindrops. A layer of 

17 plant material also creates a thick layer of still air next to the soil to buffer against wind erosion. 

18 Some practices have considered crop substitution that maintains a greater surface coverage. 

19 Implementing The implementation of practices such as conservation tillage also preserves or 

20 increases organic matter and soil structure, resulting in improved water infiltration and surface 

21 stability. In addition, creating creation of a rough soil surface through practices such as surface 

22 roughening will break the force of raindrops and trap water, reducing runoff velocity and erosive 

23 forces. 

24 Sediment transport can be reduced in several ways, including using the use of crop residues or 

25 conservation buffers. Vegetation slows runoff, increases infiltration and traps sediment. 

26 Reductions in slope length and steepness reduce runoff velocity, thereby reducing sediment 

27 carrying capacity as well. Practices are also typically needed to trap sediment leaving the field 
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Chapter 2. Agriculture 2-63 

1 before it reaches a wetland or riparian area. Deposition of sediment is achieved by practices that 

2 slow water velocity or increase infiltration. 

3 Properly functioning natural wetlands and riparian areas can significantly reduce nonpoint source 

4 pollution by intercepting surface runoff and subsurface flow and by settling, filtering, or storing 

5 sediment and associated pollutants. Wetlands and riparian areas typically occur as natural buffers 

6 between uplands and adjacent waterwater bodies. Loss of these systems allows a more direct 

7 contribution of nonpoint source pollutants to receiving waters. Degraded wetlands and riparian 

8 areas can may even become pollutant sources. Thus, natural wetlands and riparian areas should 

9 be protected and should not be used as designated erosion control practices. Their nonpoint 

10 source control functions are most effective as part of an integrated land management system 

11 focusing on nutrient, sediment, and erosion control practices applied to upland areas. 

12 Additional descriptions of erosion and sediment control practices arecan be found in previous 

13 guidance (USEPA, 2003). 

Implementation Measure: Use conservation tillage or continuous no-till on all row crops to 

reduce soil erosion and sediment loads except on those lands that have no erosion or sediment 

loss.

14 Implementation Measure: Use conservation tillage or continuous no-till on all row crops to reduce soil 

15 erosion and sediment loads except on those lands that currently have no erosion or sediment loss.

16 Conservation tillage involves little, if any, tillage in the row crop field, whereas continuous no17 till leaves all residue after harvest on the field, protecting the soil. In general, conservation tillage 

18 is any tillage system that maintains 30 percent or more of the soil surface with crop residue after 

19 planting (USDA-NRCS, 2010). The amount of residue needed to achieve erosion and sediment 

20 reduction goals, however, is dependent upon numerous factors, and the Revised Universal Soil

21 Loss Equation (RUSLE) is a tool that can help determineassist in determining the amount left on 

22 the field. 

23 Water erosion rates are affected by rainfall energy, soil properties, slope, slope length, vegetative 

24 and residue cover, and land management practices. Rainfall impacts provide the energy that 

25 causes initial detachment of soil particles. Soil properties like particle size distribution, texture,

26 and composition influence the susceptibility of soil particles to be moved by flowing water. 

27 Vegetative cover and residue canmay protect the soil surface from rainfall impact or the force of 

28 moving water. ThoseThese factors are used in the Revised Universal Soil Loss Equation 

29 (RUSLE), an empirical formula widely used to predict soil loss in sheet and rill erosion from 

30 agricultural fields, primarily crop land and pasture, and construction sites (USDA-ARS, 2005): 

31 Revised Universal Soil Loss Equation (RUSLE) 

32 A = R ×* K ×* LS ×* C ×* P

33 where

34 Where

35 A = estimated average annual soil loss (tons/acre/year) 
3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote — 

Chapter 2. Agriculture 2-64 

1 R = rainfall/runoff factor, quantifying the effect of raindrop impact and the amount and rate 

2 of runoff associated with the rain, based on long term rainfall record 

3 K = soil erodibility factor based on the combined effects of soil properties influencing 

4 erosion rates 

5 LS = slope length factor, a combination of slope gradient and continuous extent 

6 C = cover and management factor, incorporating influences of crop sequence, residue 

7 management, and tillage 

8 P = practice factor, incorporating influences of conservation practices such as contouring or 

9 terraces 

10 Practice Effectiveness 

11 Past reviews of the effectiveness of sediment control measures have concluded that reduced 

12 tillage systems reduce TP losses by 45 percent, TN losses by 55 percent, and sediment losses by 

13 75 percent (USEPA 2003). 

14 Harmel et al. (2006, 2008) have compiled measured annual N and P load data representing field 

15 scale transport from agricultural land uses. The 2006 compilation includesincluded results from 

16 40 scientifically peer-reviewed studies, but draws heavily from the 1980s. The more recent data 

17 (2008 update) include 15 additional studies. In all, the database contains 1,677 watershed years 

18 of data for various agricultural land uses and practices. Most data are from the 

19 Southeastsoutheast and upper Midwest, with only one study, from the Chesapeake Bay Drainage 

20 area. Table 2-17,Exhibit 1, below, provides a summary of median N and P loadings from Harmel 

21 et al. (2006) from which N and P reductions could be estimated. The current version can be 

22 downloaded at http://www.ars.usda.gov/spa/manage-nutrient. 

23 Table 2-17Exhibit 1. Median N and P loadings (source Harmel et al. 2006).

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 0.93a
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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 different (a – 0.05).

**No particulate N or P data were available for sandy soils.

1 

2 

3 

4 In another literature review, Merriman et al. (2009) developed a compilation of BMP 

5 effectiveness results. Table 2-18Exhibit 2 presents a listing of individual results for conservation 

6 tillage practices along with percent reductions for TP, TN, and sediment. Additional data on 

7 reductions for particulate P, dissolved P, NO3-N, and ammonium are also available. 
3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote — 

Chapter 2. Agriculture 2-66 

1 Table 2-18Exhibit 2. TP, TN, and sedimentSediment reductions for various conservation tillage 

2 practices as compiled by Merriman et al. (2009).

Reference (as 

cited by 

Merriman et al. 

2009)Reference 

(as cited 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 Missouri 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

Mutchler and 

Greer, 1984

StateMississip

pi

BMP 

nameNotill

Study 

scaleField 

plot

SLOPES

3-8

HSG

C TP % TN %

Total 

sediment 

%94.08

Zhu et al. 

1989Mutchler 

and Greer, 1984

MissouriMississi

ppi

Winter 

cover 

cropNo-till

Field plot 0-3-8 DC 92%.7

ZhuLangdale et 

al. 19891979

MissouriGeorgia Winter 

cover 

cropNo-till

Field 

plotSmall 

watershed

0-3-8 DB 90%86

ZhuLangdale et 

al. 19891979

MissouriGeorgia Winter 

cover 

cropNo-till

Field 

plotSmall 

watershed

0-3-8 DC 92%86
3/15/2010 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 cited by 

Merriman et al. 

2009) State BMP NAME Study Scale SLOPES HSG

Total 

P %

Total N 

%

Total 

Sediment 

%

Mutchler and 

McDowell 

1990Dabney et 

al. 1993

Mississippi Winter 

cover 

cropNo-till

Field plot 3-8 C 72.3%56.76

LangdaleDabney

et al. 19791993

GeorgiaMississi

ppi

No-till Small 

watershedFiel

d plot

0-3-8 BC 86%50

LangdaleDabney

et al. 19791993

GeorgiaMississi

ppi

No-till Small 

watershedFiel

d plot

0-3-8 C 86%66.67

McGregor and 

Greer 

1982Dabney et 

al. 1993

Mississippi No-till Field plot 3-8 BC 95.49%83.3

3

BergYoo et al. 

1988 

OklahomaAlaba

ma

No-till Small 

watershedFiel

d plot

3-8 B 22.5% 7.6%23.8 20.8%52.3

Mutchler et al. 

1985Schreiber 

and Cullum, 1998

Mississippi No-till Field 

plotLarge 

watershed

3-8 C 76.52 67.68 47%

McDowell and 

McGregor 

1980Meyer et al. 

1999

Mississippi No-till Field plot 3-8 C 84% 90% 99%88.47

McGregor and 

Greer 

1982Mostaghimi, 

Dillaha, 

Shanholtz 1988

MississippiVirgin

ia

No-till Field plot 3-8-15 C 97 95.49%98

YooMostaghimi

et al. 19861992

AlabamaVirginia No-till Field plot 3-8-15 BC 65.52 -

2.76%90.

55

54.44%69.4

7

MeyerMostaghim

i et al. 19991991

MississippiVirgin

ia

No-till Field plot 3-8-15 C 90.55 85.11%94.7

5

MeyerFeagley et 

al. 19991992

MississippiLouisi

ana

No-till Field plot 3-

8<N/A>

CD 90.84%74.2

5

Hairston et al. 

1984Daniels and 

Gilliam., 1996

MississippiVirgin

ia

No-till with 

subsurface 

injection

Field plot 3-8 DB 91 16.28%92

McGregorMostag

himi et al. 

19751991

MississippiVirgin

ia

No-till with 

subsurface 

injection

Field plot 3-8-15 BC 95.42 85.71%

McGregor et al. 

1975and Greer, 

1982

Mississippi NotillReduced 

Tillage

Field plot 3-8 C 85.71%91.8

4

MutchlerMcGreg

or and Greer

1984, 1982

Mississippi NotillReduced 

Tillage

Field plot 3-8 CB 94.08%91.8

4
3/15/2010 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 cited by 

Merriman et al. 

2009) State BMP NAME Study Scale SLOPES HSG

Total 

P %

Total N 

%

Total 

Sediment 

%

Mutchler and 

GreerHairston et 

al. 1984 

Mississippi NotillReduced 

Tillage

Field plot 3-8 CD 92.7%13.85

Langdale et al. 

1979Mutchler 

and Greer, 1984

GeorgiaMississi

ppi

NotillReduced 

Tillage

Small 

watershedFiel

d plot

3-8 BC 86%58.78

LangdaleTruman

et al. 19792003

GeorgiaAlabama No-tillCover 

crop 

(general)

Small 

watershedFiel

d plot

3-

8<N/A>

CB 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. 2009
3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote — 

Chapter 2. Agriculture 2-69 

1 Soil loss and ortho-P transport were measured from a conventional and two conservation tillage 

2 treatments (zero and ridge tillage) from January 1988 to September 1990 in southwestern 

3 Ontario (Gaynor and Findlay 1995). Compared to conventional tillage, conservation tillage 

4 reduced average soil loss by 49 percent (899 kg/ha) and increased ortho-P concentrations in 

5 runoff 2.2 times (0.25 mg/L). 

6 Using a rain simulator on plots, Avalos et al. (2007) found that corn straw residue decreased N 

7 losses from 88.82 to 16.65 kg/ha (81 percent reduction) and decreased TP losses from 7.87 to 

8 1.72 kg/ha (78 percent reduction). In another plot study using rainfall simulation, it was found 

9 that under no-till conditions, plots with corn residue and grass hedges averaged 52 percent less 

10 runoff and 53 percent less soil loss than similar plots without grass hedges (Gilley et al. 2000). 

11 Under tilled conditions, the plots with corn residue and grass hedges averaged 22 percent less 

12 runoff and 57 percent less soil loss than comparable plots without grass hedges. The plots with 

13 corn residue removed but with grass hedges present averaged 41 percent less runoff and 63 

14 percent less soil loss than similar plots without grass hedges. 

15 One alternative to reduce compaction and restricted infiltration under long periods of no-till is 

16 rotational tillage (Smith et al. 2007). In the first year of converting from long-term, no-till to 

17 rotational tillage on small plots that had been in a no-till corn-soybean rotation for 15 years, 

18 runoff volumes and nutrient concentrations for NH4-N, NO3-N, and dissolved P (DP) were 

19 greater from the no-till field. Before Prior to fertilization, no-till resulted in 83 g/ha greater NH4-

20 N and 32.4 g/ha greater dissolved P losses than rotational tillage. After fertilization, no-till was 

21 observed to lose 5.3 kg/ha more NH4-N, 1.3 kg/ha more NO3-N, and 2.4 kg/ha more dissolved P 

22 than rotational tillage. 

23 Conventional tillage, conservation tillage with cover crop, and no-till with cover crop were 

24 compared in a small grain-corn rotation in Austria in a field study from 1994 to -1999 (Klik et al. 

25 2001). The field plots ranged from 3 to -4 m in width and 15- m long, and slope ranged from 6 to 

26 -16 percent. Runoff was not statistically different among the practices, but nutrient losses from 

27 April to October were 13.7 kg/ha for conventional tillage, 9.1 kg/ha (34 percent decrease) for 

28 conservation tillage, and 7.7 kg/ha (44 percent decrease) for no-till. PPhosphorus losses were 6.5, 

29 3.1 (52 percent decrease), and 2.0 kg/ha (69 percent decrease), respectively. In a 9-year field 

30 study in Finland, Puustinen et al. (2005) found that traditional cultivation treatments produced 

31 the highest TSS concentrations (1.38 and 1. 18 mg/L, respectively), whereas values between 0.44 

32 and 0.53 mg/L were measured for three treatments with reduced (or no) tillage. Particle-bound P 

33 concentrations closely followed those of TSS, but DRdissolved reactive P showed contrasting 

34 behavior. 

35 Finish researchers (Turtola et al. 2007) found that the frequency of tillage, rather than the depth 

36 of tillage, has a greater effect on erosion on clayey soils. Shallow autumn tillage produced 

37 erosion as high as mouldboard ploughing (407–-1700 kg/ha-yr), but 48 percent and 12 percent 

38 lower erosion levels were measured from plots left untilled in autumn, covered by grass or barley 

39 residues, respectively. In a companion study, Uusitalo et al. (2007) found that stubble treatment 

40 yielded higher dissolved reactive P (DRP) losses (104–-259 g/ha-yr) than autumn ploughing (77–

41 -96 g/ha-yr), and equally high particulate P (PP) losses (mean 660, 235–-1,300 g/ha-yr). Shallow 

42 autumn tillage produced 28 percent higher DRP losses (mean 120, 107–-136 g/ha-yr) than 
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Chapter 2. Agriculture 2-70 

1 ploughing (83–-117 g/ha-yr) and 11 percent higher PP losses (mean 1,090, 686–-1,336 g/ha-yr) 

2 than ploughing (783–-1253 g/ha-yr). 

3 Practice Costs 

4 In an analysis of various combinations of practices to control sediment loss in a 12- ha 

5 subwatershed of the Mississippi Delta Management System Evaluation Area using the 

6 Annualized Agricultural Nonpoint Source pollutant loading model (AnnAGNPS 2.1), it was 

7 found that the most cost-effective practices were management of volunteer winter weeds as 

8 cover crops and various types of edge-of-field, grade-control pipes (Yuan et al. 2002; Dabney et 

9 al. 2001). The average marginal cost using practices for sediment yield reduction was about 

10 $10/MT (2008 dollars/metric ton) for conventional and reduced tillage. The cost was higher, 

11 about $13/MT for no-till because the practice of no-till alone reduced sediment yield by half, and 

12 further marginal reductions were more expensive. 

13 Using the Water Erosion Prediction Project (WEPP) model calibrated to a 6.4-ha site within Four 

14 Mile Creek watershed in eastern Iowa, Zhou et al. (2009) compare the cost of lost soil for chisel 

15 plow, disk tillage, and no-tillage. The value of lost soil resulting from soil erosion ranged 

16 between $10.9 and $137.3/ha-yr for the simulated scenarios in the study when a soil value of 

17 $6.1/t was considered. When factoring in the value of soil, no-tillage was the most efficient 

18 practice with the highest net benefit of $94.5/ha-yr. 

19 Using the Raritan Basin in New Jersey, Qiu et al. (2009) compare the placement of fixed-width 

20 buffers based on regulatory rules, variable-width buffers based on watershed initiatives, and 

21 variable source area-based conservation buffer placement strategy derived from an alternative 

22 concept of watershed hydrology. The variable source area-based conservation buffer placement 

23 strategy targets the most hydrologically critical source areas in a watershed tier buffer placement. 

24 The authors show that there is little difference in cost effectiveness between fixed- and variable25 width buffers, but that the variable source area-based buffer placement strategy is more cost26 effective. 

27 Both national and selected state costs for a number of common erosion control practices are 

28 presented in Table 2-1917. The variability in costs for practices can be accounted for primarily 

29 through differences in site-specific applications and costs, differences in the reporting units used, 

30 and differences in the interpretation of reporting units. 

31 The cost estimates for control of erosion and sediment transport from agricultural lands in Table 

32 2-2018 are based on experiences in the Chesapeake Bay Program. 

33 Practice Savings 

34 It is important to note that for some practices, such as conservation tillage, the net costs often 

35 approach zero and in some cases can be negative because of the savings in labor and energy. In 

36 fact, it is reported that cotton growers can lower their cost per acre by $24.32 because ofdue to

37 lower fixed costs associated with conservation tillage (Zeneca, 1994). 

38 Table 2-1917. Representative costs of selected erosion control practices. 

Practice Unit

Range of capital 

costsacosts1 References
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Chapter 2. Agriculture 2-71 

Diversions ft $1.97–$5.51 Sanders et al. 1991 

Smolen and Humenik, 1989

Terraces ft 

a.s.b2

$3.32–$14.79 

$24.15–$66.77

Smolen and Humenik, 1989 

Russell and Christiansen, 1984

Waterways ft 

ac 

a.e.c3

$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 ratio of indices of prices paid by farmers for all production 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/1991 Prices 

Paid by Farmers, according to USDA National Agricultural Statistics Service, 

http://www.usda.gov/nass/sources.htmhttp://www.usda.gov/nass/ sources.htm, 28 September, 1998] 

1 

2 Table 2-2018. Annualized cost estimates and life spans for selected management practices from 

Chesapeake Bay installationsaInstallationsa3 (Camacho, 1991). 

Practice Practice life span 

Median annual costsb

(Years) (eacc)

($/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 Tillaged1 17.34

Reforestation of Crop and Pastured 10 46.66

Grassed Waterwayse10 1.00/LF/yr

Animal Waste Systemf10 3.76/ton/yr

Source: Camacho 1991 

Notes:

a. Median costs (1990 dollars) obtained from the Chesapeake Bay Program Office (CBPO) BMP tracking data 

base and Chesapeake Bay Agreement Juristictions’ unit data cost. Costs per acre are for acres benefited by 

the practice. 

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

c. EAC = equivalentEquivalent annual cost: annualized total; costs for the life span. Interest rate = 10%. 
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Chapter 2. Agriculture 2-72 

d. Government incentive costs. 

e. Annualized unit cost per linear foot of constructed waterway. 

f. Units for animal waste are given as $/ton of manure treated. 

1 

2 3.3 Cover Crops 

Implementation Measure: Use the most suitable cover crops for the site on all acres that have 

received any manure or chemical fertilizer application. Cover crops should be used during a nongrowing season (including winters) or when there is bare land in a field.

3 Implementation Measure: Use the most suitable cover crops for the site on all acres that 

4 have received any manure or chemical fertilizer application. Cover crops should be used 

5 during a non-growing season (including winters), or when there is bare land in a field.

6 Cover crops, also called catch crops or relay crops, are grasses, legumes and forbs used for 

7 seasonal cover and other conservation purposes. Cover crops provide those lands in active or 

8 fallow production a rooted plant to take in residual or excess nutrients as well as hold the soil in 

9 place, thus extending the growing season. They can be incorporated into bare earthen rows 

10 during a cropping season for corn, vegetables and many other row crops grown in the 

11 Chesapeake Bay. They can also be an excellent stabilizer during the non-growing season across 

12 the entire expanse of field. By extending the growing season, excess nutrients are taken up as 

13 well as additional water, thus lessening the need for intensive drainage. Cover crops provide a 

14 cover to the soil, and provide a host of benefits to water quality. 

15 Cover crops include living mulches, winter cover crops and perennials. Living mulches are 

16 planted before prior to or during the main row crop planting, and are maintained throughout the 

17 growing season. TheyThese can be perennial species with annual maintenance. The living mulch 

18 is not meant to take nutrients away from the main row crop;, rather, the producer should plant a 

19 species that is suppressed during the intensive growth period of the main crop and is taking in 

20 excess available nutrients and is growing as the main row crop matures or after it is harvested. 

21 However, in growing suchthese crops in tandem, the living mulch will compete to a degree with 

22 the main row crop for both water and nutrient uptake. Both perennial legumes and grasses are 

23 options as living mulches. Perennials are row crops planted once and intended to stay in place 

24 over multiple years. 

25 In general, a cover crop is planted shortly before or soon after the main row crop is harvested. It

26 is then , and killed or removed before or soon after planting of the subsequent season’s main row 

27 crop. The cover crop remains on the field through the winter and is harvested or plowed under in 

28 the spring beforeprior to planting. As described in NRCS Conservation Practice Standard code 

29 340, cover crops canmay be used on any land where vegetative cover is needed for natural 

30 resource protection or improvement. Cover crops mightmay be beneficial for controlling 

31 nonpoint source pollution where they are used to do the following: 

32 • Reduce erosion from wind and water which can carry nutrients and sediments to surface 

33 waters 
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Chapter 2. Agriculture 2-73 

1 • Capture and recycle or redistribute nutrients in the soil profile to reduce nutrient 

2 availability to be transported from agricultural lands through runoff or leaching 

3 • Promote biological Nnitrogen fixation through use of leguminous cover crops to reduce 

4 the need for addition of Nnitrogen fertilizer to subsequent crops 

5 • Minimize and reduce soil compaction, thereby improving infiltration and reducing the 

6 rate and volume of runoff from agricultural lands.

7 The Midwest Cover Crop Council Web site (www.mccc.msu.edu/CCinfo/cropbycrop.html) 

8 provides information on the variety of options for planting cover crops, and describes the plant 

9 species that are grasses, legumes, brassicas, and other non-legume broad- leafed plants. 

10 Practice Effectiveness 

11 Nutrient Reduction 

12 Staver and Brinsfield (1998) investigated the effects of cereal grain winter cover crops on nitrate 

13 leaching rates, profile nitrate storage, and nitrate concentrations in shallow groundwater in two 

14 field-scale watersheds planted continuously in corn (Zea mays L.) from 1984 through 1996. Rye 

15 winter cover crops planted after corn harvest consistently reduced nitrate-N concentrations in 

16 root zone leachate to less than 1 mg/L during most of the groundwater recharge period, and 

17 reduced annual nitrate leaching losses by approximately 80 percent relative to winter-fallow 

18 treatments. Shallow groundwater nitrate-N concentrations under long-term continuous corn 

19 production decreased from the 10 to 20 mg/L range to less than 5 mg/L after 7seven years of 

20 cover crop use. 

21 A 3-year field experiment was conducted on sandy loam soils in southwestern Michigan to 

22 investigate the combined effects of N fertilization rates and rye cover crops on NO3 leaching in 

23 inbred maize fields (Rasse et al. 2000). Annual NO3 leaching losses to ground water fertilized at 

24 202 kg N/ha averaged 88 kg NO3-N/ha, but rye interseeded with inbred maize fertilized at 202 

25 kg N/ha sequestered from 46 to 56 kg/ha of excess fertilizer N. Well-established rye cover crops 

26 reduced NO3 leaching by as much as 65 kg N/ha when the previous crop was fertilized with 202 

27 kg N/ha, but rye scavenged little residual fertilizer N in plots fertilized at 101 kg N/ha. 

28 In Iowa, Singer et al. (2008) measured the effects of winter small-grain cover crops (CC) and 

29 subsequent liquid manure injection (N rates of 112, 224, and 336 kg N/ha) on nutrient uptake and 

30 corn yield. Although fall (but not spring) CC dry matter (DM) was 26 percent lower with manure 

31 than without manure, no difference was detected for N (9.4 kg/ha) or P (1.4 kg/ha) uptake. Shoot 

32 dry matter (DM) and N, P, and K uptake increased 29, 41, 31, and 25 percent, respectively, from 

33 the CC manure 112 kg N/ha treatment to the CC manure 224 kg N/ha treatment, with no increase 

34 above the CC manure 224 kg N/ha treatment. Cover crop N, P, and K uptake were all higher in 

35 CC manure versusvs. no manure (60.1 versusvs. 35.6 kg/ha, 9.2 versusvs. 6.6 kg P/ha and 41.3 

36 versusvs. 30.0 kg K/ha, respectively), while corn yield was unaffected by CC and responded 

37 positively to manure application (11,022 with manure versusvs. 9,845 kg/ha without manure). 

38 In a field study to determine the potential of a Bermuda bermudagrass/ryegrass combination to 

39 reduce the level of Mehlich 3 P that had accumulated in a Savannah soil from broiler litter 

40 application over 30 years, coupled with antecedent litter rates of 0, 4.48, 8.96, 17.9, and 35.8 

41 Mg/ha, Read et al. (2009)it was found that annual DM yield and P uptake generally increased as 
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Chapter 2. Agriculture 2-74 

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

2 (0–-15 cm depth) at four sampling dates over 19 months showed reductions of 25, 27, 22, 26, 

3 and 29 percent at the five antecedent litter rates, respectively. Ryegrass-Bermuda bermudagrass 

4 significantly increased DM yield and P uptake, but did not increase reductions in Mehlich 3 P, as

5 compared to Bermuda bermudagrass winter fallow, and both forage systems removed about 49 

6 kg/ha P and reduced Mehlich 3 P by about 26 mg/kg annually via five harvests per year. 

7 Sharma and Sahi (2005) examined the phytoremediation potential of Gulf and Marshall ryegrass 

8 grown in a greenhouse under varying conditions of soil P concentration, pH, and temperature, 

9 finding that an increase in plant biomass was proportional to the increasing concentrations of P 

10 up to a level of 10 g of P/kg of soil. Significant effects of both soil pH and temperature on plant 

11 uptake of P were measured, and the researchers concluded that Gulf and Marshall ryegrass can 

12 accumulate high P under optimal conditions and thus reduce soil P concentrations in successive 

13 cropping. 

14 Sediment Reduction 

15 A 2-year study comparing sediment, N, and P runoff losses for cotton managed with winter 

16 fallow and conventional tillage versus cotton managed with a winter wheat cover crop and strip17 tillage, found that the cover crop/strip-till treatment reduced sediment loss for all sampling dates, 

18 especially in 2000 when sediment losses were less than half of those with conventional tillage. 

19 Sediment loss was also reduced with cover crop/strip-till during the early growing season, before 

20 crop canopy closure, and vegetative field borders further reduced runoff of sediment and sedi21 ment-attached P (Hoyt 2005). 

22 Van Vliet et al. (2002) compared different fall-manure application strategies on runoff and 

23 contaminant transport from silage corn land in the Lower Fraser Valley of British Columbia. The 

24 treatments were a control that did not receive manure in the fall, manure broadcast in the fall on 

25 corn stubble, and manure broadcast in the fall on corn stubble with an established relay crop. 

26 Runoff, solids, and nutrients loads from natural precipitation were measured on replicated 

27 experimental plots (0.0125 ha) from 1996 to 1998. Fall-applied manure on 3–-5 percent sloping 

28 silage cornland without a relay crop yielded high suspended solids loads of between 7 and 14 

29 Mg/ha/yr and high nutrient transport with mean annual total Kjeldahl N (TKN,) P, and K loads 

30 of 98, 21, and 63 kg/ha respectively. Compared with no relay crop, intercropping silage corn 

31 with a relay crop of Italian ryegrass reduced the mean annual runoff and suspended solid load by 

32 53 and 74 percent, respectively, TKN load by 56 percent, P load by 42 percent, K load by 31 

33 percent, and Cu load by 57 percent. Even though total nutrient loads were lower with the relay 

34 crop treatment, all fall manure treatments including the relay crop resulted in nutrient loads 

35 above local guidelines for the first three runoff events immediately following application. 

36 Practice Costs 

37 The Chesapeake Bay Commission (2004) evaluated 34 nutrient and sediment- reduction 

38 practices representing a wide range of specific actions associated with wastewater treatment 

39 plants, agriculture, urban stormwater, land preservation, forestry, and air pollution. The analysis 

40 resulted in identifying identification of six measures that could achieve a substantial portion of 

41 the N, P,nitrogen, phosphorus and sediment- reduction goals set for the period 2002–20010 in 

42 the Chesapeake 2000 agreement. One of those practices is enhanced adoption of late cover crops 
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Chapter 2. Agriculture 2-75 

1 and use of early cover crops to absorb excess nutrients in the soil. The report estimates that 

2 implementing implementation of fall cover crops at the maximum extent feasible (2.05 million 

3 acres) in the watershed could achieve annual Nnitrogen reductions of 15.2 million pounds of 

4 Nnitrogen at $3.50 per pound, and 0.22 million pounds of P,phosphorus and 0.11 million tons of 

5 sediment at no additional cost. Maximum feasible implementation of early cover crops could 

6 provide annual reductions of 8.1 million pound of Nnitrogen at $2.33 per pound and 0.22 million 

7 pounds of Pphosphorus and 0.11 million tons of sediment at no additional cost. 

8 Saleh, et al. (2005) used the modified SWAT (SWAT-M) and FEM (Farm-level Economic 

9 Model) models to evaluate the environmental and economic impacts of various BMP scenarios 

10 often adopted by local farmers to reduce sediment and nutrient loadings (in particular NO3-N). 

11 Measured values of water quality indicators from the Walnut Creek watershed (WCW) located in 

12 central Iowa were used to verify the capability of SWAT-M to predict the impact of late-spring 

13 nitrate test (LSNT) and rye cover crop management on NO3-N reduction at the subbasin level. 

14 The results obtained from SWAT-M simulation results, similar to field measurement data, 

15 indicated a 25 percent reduction in NO3-N under the LSNT scenario. FEM results indicated a

16 corresponding increased annual cost of $6/ha across all farms in the watershed. Simulating

17 Simulation of other scenarios, including winter cover cropping and a combination of LSNT and 

18 cover cropping at different adoption rates within WCW, resulted in a progressive reduction in 

19 sediment and nutrient losses as adoption rates increased. Using Use of the rye cover crop added 

20 about $25/ha to $35/ha to the annual cost of the average farm, indicating that some cost-share 

21 support mightmay be necessary to encourage farmers to use winter cover crops. 

22 In an application of the Annualized Agricultural Nonpoint Source pollutant loading model 

23 (AnnAGNPS 2.1) to a 12-ha Mississippi Delta Management System Evaluation Area 

24 (MDMSEA) subwatershed, cover crops, filter strips, grade control pipes, and impoundments 

25 were modeled in combination with three tillage systems: conventional tillage, reduced tillage, 

26 and no-till (Yuan, et al. 2002). Costs of BMPs were estimated using 2001 state average prices for 

27 Mississippi, and amortized fixed costs—, using a 25-year planning horizon and interest rates of 

28 both 5 percent and 10 percent—, were combined with direct annual costs into total annual cost 

29 estimates. AnnAGNPS predicted that no-till alone, reduced tillage with winter cover and an 

30 edge-of-field pipe, or conventional tillage with a small permanent impoundment (covering less 

31 than 3 percent of the watershed) would all reduce sediment yield by at least 50 percent. The most 

32 cost-effective BMPs were managing management of volunteer winter weeds as cover crops and 

33 various types of edge-of-field grade-control pipes. The average marginal cost using BMPs for 

34 sediment yield reduction was about $8/MT ($7.3/t) for conventional and reduced tillage. The 

35 cost was higher, about $10.7/MT, ($9.7/t) for no-till because the practice of no-till alone reduced 

36 sediment yield by half, and further marginal reductions were more expensive. 

37 In an assessment of options to address nitrate problems in the Neuse River Basin of North 

38 Carolina, it was concluded that cover crops can reduce Nnitrogen loading of shallow 

39 groundwater by 5 to 15 percent (Wossink 2001). Conservation tillage, including cover crops, is 

40 identified as one of the three best options for Nnitrogen reduction in the Piedmont region, and 

41 the cost of a wheat cover crop is estimated at $76/acre with $0 in net receipts, for a net revenue 

42 of -$76/acre. 

43 Franzluebbers (2005) summarizes research on some of the key components that could produce 

44 viable integrated crop-livestock production systems in the Southeast: sod-based crop rotation, 
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Chapter 2. Agriculture 2-76 

1 cover cropping, intercropping, and conservation tillage. Despite its agronomic benefits, 

2 adoptingthe adoption of cover cropping appears to be limited because of cost without immediate 

3 economic benefit, but the author suggests that grazing of cover crops could provide such an 

4 immediate economic benefit to producers. On the basis ofBased on the research reviewed, 

5 barriers to adoptingadoption of integrated crop–livestock systems include lack of experience or 

6 time to manage both the crops and livestock. Several studies regarding economic returns from 

7 grazing livestock were reviewed, and Franzluebbers found the following: 

8 • Livestock increased labor required on an average North Dakota farm by about 50 percent, 

9 but only about 30 percent of the additional time competed directly during critical crop 

10 management. Net economic return attributed to livestock increased whole farm income 

11 by about 20 percent. 

12 • Ten steers and heifers were grazed on a 4-ha area of rye or ryegrass cover crop at the 

13 Sunbelt Agricultural Exposition near Moultrie, GeorgiaGA. The equivalent of $311 

14 ±$62/ha greater gross income was generated in the value of animal gain (assuming 

15 $1.75/kg animal gain). 

16 • A 3-year experiment was conducted at Headland, AlabamaAL, to compare the effect of 

17 oat and ryegrass winter cover crops under cattle grazing on cotton and peanut production 

18 managed under different tillage systems. Net return from winter grazing of cover crops (5 

19 head/ha for 80 d) was $185 to $200/ha/yr. 

20 • Using an economic model comparing a conventional system (53 ha cotton, 27 ha peanut) 

21 with a sod-based rotation system (20 ha cotton, 20 ha peanut, 40 ha bahiagrass) on a 

22 typical small farm in Florida, net profit was expected to be $15,689/yearyr on a 

23 conventional farm and $44,840/yearyr on a sod-based farm with cattle grazing the

24 second2nd year bahiagrass. 

25 3.4 Pasture Land Management 

Implementation Measure: Minimize nutrient and soil loss from pasture land by maintaining

uniform livestock distribution over the pasture, keeping livestock away from riparian areas, and 

managing stocking rates and vegetation to prevent pollutant losses through erosion and runoff.

26 Implementation measure: Minimize nutrient and soil loss from pasture land by 

27 maintaining uniform livestock distribution over the pasture, keeping livestock away from

28 riparian areas, and managing stocking rates and vegetation to prevent pollutant losses 

29 through erosion and runoff.

30 In addressing nonpoint source pollution concerns, producers shouldmust balance production and 

31 water quality objectives. This section explores some of the production-oriented resources 

32 management decisions confronting livestock producers. 

33 Livestock can obtain their needed nutrients through feed supplied to them in a confined livestock 

34 facility, through forage, or through a combination of forage and feed supplements. Forage 

35 systems can be pasture-based or rangeland-based. 
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1 It is important for the reader to be aware of the difference between rangeland and pasture. 

2 Rangeland refers to those lands on which the native or introduced vegetation (climax or natural 

3 potential plant community) is predominantly grasses, grasslike plants, forbs, or shrubs suitable 

4 for grazing or browsing. Rangeland includes natural grassland, savannas, many wetlands, some 

5 deserts, tundra, and certain forb and shrub communities. Pastures are those improved lands that 

6 have been seeded, irrigated, and fertilized and are primarily used for producingthe production of

7 adapted, domesticated forage plants for livestock. Other grazing lands include grazable forests, 

8 native pastures, and crop lands producing forage. 

9 The major differences between rangeland and pasture are the kind of vegetation and level of 

10 management that each land area receives. In most cases, range supports native vegetation that is 

11 extensively managed through the control of livestock rather than by agronomy practices, such as 

12 fertilization, mowing, or irrigation. Rangeland also includes areas that have been seeded with 

13 introduced species (e.g., clover or crested wheatgrass) but are managed with the same methods 

14 as native range. For both rangeland and pasture, the key to good grazing practice is vegetative 

15 management, i.e., timing of grazing should be managed to ensure adequate vegetative regrowth 

16 and soil stability. 

17 Pastures are represented by those lands that have been seeded, usually with introduced species 

18 (e.g., legumes or tall fescue) or in some cases with native plants (e.g., switchgrass or needle 

19 grass), and thatwhich are intensively managed using agronomy practices and control of livestock. 

20 Permanent pastures are typically based on perennial, warm-season (e.g., Bermuda bermudagrass) 

21 or cool-season (e.g., tall fescue) grasses and legumes (e.g., warm-season alfalfa, cool-season red 

22 clover), while temporary pastures are generally plowed and seeded each year with annual 

23 legumes (e.g., warm-season lespedezas, cool-season crimson clover) and grasses such as warm24 season pearl millet and cool-season rye (Johnson et al. 1997). PlantsPlant selection for pastures 

25 should selected on the basisbe based upon consideration of climate, soil type, soil condition, 

26 drainage, livestock type and expected forage intake rates, and the type of pasture management to 

27 be used. Management of pH and soil fertility is essential to both establishingthe establishment

28 and maintaining maintenance of pastures (Johnson et al. 1997). In some climates (e.g., Georgia), 

29 overseeding of summer perennials with winter annuals is done to provide adequate forage for the 

30 period from mid-winter to the following summer. 

31 Approaches to reducing pollutant runoff from pasture land address managing animal stocking 

32 rates and maintaining vigorous vegetation to provide for soil stability and nutrient recycling. 

33 Based on a review of the literature, Osmond et al. (2007) recommendrecommended that practices 

34 should be used that encourage more uniform livestock distribution over the pasture; riparian 

35 areas should not be used as shade paddocks, holding areas, or feeding areas; and access to 

36 riparian areas should be limited and should not occur when soils are wet or boggy, and when 

37 acceptable forage is available on non-riparian sites within the same grazing unit. Good pasture 

38 management maintains stocking rates and vegetation to prevent pollutant losses through erosion 

39 and runoff; silvopasture techniques integrate trees into pastures to improve nutrient uptake and 

40 vegetation stability. A discussion of forestry practices and methodologies that can be 

41 incorporated into silvopasture arecan be found in Chapter 4. 

42 Practice Effectiveness 

43 Pasture management 
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Chapter 2. Agriculture 2-78 

1 In a Georgia plot study, Butler et al (2008b) compared runoff and sediment and nutrient export 

2 from poorly drained and well- drained riparian soils where heavy or light grazing pressure by 

3 cattle was simulated. Runoff volume was generally greater from heavily grazed areas than from 

4 lightly grazed areas. Light-use plots were effective at minimizing export of TSS on both soils 

5 (< 30 kg/ha). Mean TPtotal P export was fourfold greater from heavy-use plots than from light6 use plots on both soils. While export of nitrate-nitrogen (NO3-N) was unaffected by grazing 

7 pressure and soil drainage, mean ammonium-nitrogen (NH4-N) and Ttotal N export from poorly 

8 drained heavy-use plots was greater than fivefold that from well-drained light-use plots. Results 

9 indicate that livestock heavy-use areas in the riparian zone canmay export substantial TSS and 

10 nutrients, especially on poorly drained soils. However, when full ground cover is maintained on 

11 well-drained soils, TSS and nutrient losses canmay be limited.

12 Sistani et al. (2008) investigated the effectimpact of pasture management and broiler litter 

13 application rate on nutrient runoff from Bermuda bermudagrass pasture plots in Kentucky. 

14 Runoff was 29 percent greater from grazed than hayed pastures regardless of the litter 

15 application rate. There was greater inorganic N in the runoff from grazed paddocks when litter 

16 rate was based on N rather than P. The mean TPtotal P loss per runoff event for all treatments 

17 ranged from 7 to 45 g/ha and the grazed treatment with litter applied on N basis had the greatest 

18 Ttotal P loss. The SRsoluble reactive P was greater for treatments with litter applied on N basis 

19 regardless of pasture management. Litter canmay be applied on an N- basis if the pasture is 

20 hayed and the soil P is low. In contrast, litter rates should be based on a P-basis if pasture is 

21 grazed.

22 Introduction of cattle to consume the cover crop forage in Georgia did not cause substantial 

23 damage to the soil (Franzluebbers and Stuedemann 2008). Grazing of cover crops had little 

24 effect on soil bulk density. Stability of macroaggregates in water was unaffected by grazing of 

25 cover crops. There was a slight tendency for water infiltration rate to be lower with grazing of 

26 cover crops (5.6 mm/min) than when ungrazed (6.9 mm/min),). 

27 In New Zealand, McDowell and Houlbrooke (2009) assessed restricted grazing and applying the 

28 application of aluminum sulfate for their potential to decrease contaminant loss from winter 

29 grazing of forage crops. Volumes of surface runoff and loss of P and sediment showed 

30 significant differences between the control treatments (i.e., no mitigation) with cattle crop (88 

31 mm surface runoff) greater than> sheep crop (67 mm) greater than> sheep pasture (33 mm). 

32 Restricted winter grazing and alum application after grazing significantly decreased P losses in 

33 surface runoff under cattle (from 1.4 to 0.9 kg P/ha, 36 percent) and sheep (from 1.0 to 0.7 

34 kg/P/ha, 30 percent). In cattle- grazed plots, restricted grazing also decreased suspended 

35 sediments by 60 percent. 

36 Owens and Shipitalo (2009) evaluated two systems of over-wintering cattle in Ohio. Vegetative 

37 cover in the continuous wintering area frequently decreased to less than 50 percent by late 

38 winter/early spring while it remained at or near 100 percent in the rotational system. Annual 

39 runoff from the rotational wintering system was 69 percent lower than from the continuous 

40 wintering system; sediment loss was also reduced by 91 percent under the rotational system 

41 compared to continuous wintering. Surface runoff losses of N from the continuous system were 

42 double those from the rotational system during the dormant season. Some of thethese differences 

43 could be attributed to higher cattle occupancy rate in the continuous wintering system. 
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Chapter 2. Agriculture 2-79 

1 In North Carolina, Butler et al. (2007) reported that mean nitrate N export from bare ground plots 

2 was greatest from bare ground and was reduced by 31 percent at 45 percent cover. Mean Ttotal 

3 N export was greatest from bare ground and was reduced by at least 85 percent at cover levels 

4 from 45 to 95 percent. Whereas site did not affectimpact N export, results indicateindicated that 

5 cover and time of rainfall following manure deposition are important determinants of the 

6 effectimpact of riparian grazing.

7 In a review of experimental data from the Northeast United Statesnortheast U.S., Stout et al. 

8 (2000) assessed the relationships between stocking rate and NO3-N leaching losses beneath an 

9 intensively grazed pasture. A relatively low cumulative seasonal stocking rate of about 200 

10 mature Holstein/ha could result in a 10 mg/ / NO3-N concentration in the leachate beneath a 

11 fertilized, intensively grazed pasture. ThatThis means that while management intensive grazing 

12 can improve farm profitability and help control erosion, it can have a significant negative effect 

13 on water quality beneath pastures 

14 Lyons et al. (2000) compared bank erosion, fish habitat characteristics, trout abundance, and a 

15 fish-based index of biotic integrity (IBI) among stations with riparian continuous grazing, 

16 intensive rotational grazing, grassy buffers, or woody buffers along 23 trout stream reaches in 

17 Wisconsin. After statistically factoring out watershed effects, stations with intensive rotational 

18 grazing or grassy buffers had the least bank erosion and fine substrate in the channel. Continuous 

19 grazing stations had significantly more erosion and, with woody buffers, more fine substrate. 

20 Station riparian land use had no significant effect on width/depth ratio, cover, percent pools, 

21 habitat quality index, trout abundance, or IBI score. 

22 From Minnesota, Magner et al. (2008) report reported that low IBI scores arewere associated 

23 with streams draining continuously grazed pasture, while higher IBM scores occuroccurred on 

24 nongrazed sites. Nongrazed sites were associated with reduced soil compaction and higher bank 

25 stability, whereas continuously grazed sites showshowed increased soil compaction and lower 

26 bank stability. Short-duration grazing sites arewere intermediate. 
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Chapter 2. Agriculture 2-80 

1 Table 2-2119. Summary of reported practice effects resulting from pasture management.

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 Ttotal P export 

was fourfold greater from heavy-use plots than 

from light-use plots. While export of nitratenitrogen (NO3-N) was unaffected by grazing 

pressure and soil drainage, mean ammoniumnitrogen (NH4-N) and Ttotal 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 Ttotal 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 Ttotal 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 Ttotal 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/ / NO3-N concentration in the leachate 

beneath a fertilized, intensively grazed pasture. 

Stout et al. 

2000 
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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 thethese differences could be attributed to higher cattle occupancy rate in the continuous wintering system 

1 Silvopasture 

2 In Missouri, Garrett et al. (2004) reported that many cool-season forages benefit from 40 percent 

3 to 60 percent shade, and grazing trials in such conditions have proven to be successful. Also in 

4 Missouri, Kallenbach et al. (2006) reported that cumulative forage production in annual 

5 ryegrass/cereal rye planted into a 6- to 7-year-old forested stand was reduced by approximately 

6 20 percent compared to the same forages planted in open pasture. However, beef heifer average 

7 daily gain and gain/ha were equal for both treatments, suggesting that a silvopasture system 

8 likely would not sacrifice livestock production in thethis system. In Florida, Bambo et al. (2009) 

9 documented 56 percent reduction in nitrate concentrations under silvopasture compared to 

10 conventional open pasture. 

11 Blazier et al. (2008) evaluated soil nutrient dynamics, loblolly pine nutrient composition, and 

12 loblolly pine growth of an annually fertilized silvopasture on a well drained soil in LouisianaLA

13 in response to fertilizer type, litter application rate, and subterranean clover. Litter stimulated 

14 loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff 

15 potential threshold ranges. However, both litter treatments led to accumulation of P in upper soil 

16 horizons relative to inorganic fertilizer and unfertilized control treatments. Subterranean clover 

17 kept more P sequestered in the upper soil horizon and conferred some growth benefits to loblolly 

18 pine. The authors concluded that although thethese silvopasture systems had a high capacity for 

19 nutrient use and retention, litter should be applied less frequently than in their study to reduce 

20 environmental risks.

21 In Florida, Michel et al. (2007) reported that water-soluble P concentrations in the upper soil 

22 layer ranged from 4 to 11 mg/kg for the silvopasture sites and 10 to 23 mg/kg in the treeless 

23 pasture sites, with higher P concentrations in the treeless pasture at each location. TTotal P 

24 storage capacity in the upper 1-m depth ranged from 342 to 657 kg/ha in the silvopasture sites 
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Chapter 2. Agriculture 2-82 

1 and 60 to 926 kg/ha in the treeless pasture sites (a negative value indicates that the soil is a P 

2 source). The results suggest that P buildup within the soil profile and therefore the chances for 

3 loss of P from soil to waterwater bodies were less from silvopastures than from treeless pastures. 

4 Nair et al. (2007) monitored soil N and P concentrations under a treeless pasture, a pasture under 

5 20-year-old trees, and a pasture of native vegetation under pine trees in FL.Florida. P 

6 concentrations were higher in treeless pasture (mean: 9.11 mg/kg in the surface) compared to 

7 silvopastures (mean: 2.51 mg/kg), and ammonium-N and nitrate-N concentrations were higher in 

8 the surface horizon of treeless pasture. The more extensive rooting zones of the combined stand 

9 of tree + forage may have caused higher nutrient uptake from silvopastures than treeless system. 

10 Further, compared to treeless system, soils under silvopasture showed higher P storage capacity. 

11 Table 2-2220. Summary of reported practice effects resulting from silvopasture.

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 for 

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. TTotal P storage capacity in the upper 1- m 

depth was 342 to 657 kg/ha in the silvopasture sites 

and -60 to 926 kg/ha in the treeless pasture sites (a 

negative value indicates that the soil is a P source). 

Michel et al. 

(2007 

FL Field Silvopasture Surface soil P concentrations were higher in treeless 

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 mightmay 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. 

2007 
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Chapter 2. Agriculture 2-83 

1 Practice Costs 

2 An analysis of the more than $3.5 billion spent toward nutrient controls in the Chesapeake Bay 

3 watershed between 1985 and 1996 found that nutrient management (e.g., USDA-NRCS 

4 Conservation Practice 590) was the least costly practice for nutrient control (Butt and Brown,

5 2000). 

6 Giasson et al. (2003) examined the cost- effectiveness and the risk of P loss associated with 

7 various combinations of manure management options for a typical midsized dairy farm in New 

8 YorkNY using mathematical programming techniques and utility functions to select optimum 

9 management practices. Compared with current practices, the recommended combination of 

10 practices resulted in an approximate 45 percent reduction in the mean area-weighted P Index 

11 (64.2 versusvs. 36.1) for a cost (2008 dollars) increase of less than 2 percent ($171,235 versusvs.

12 $173,860). 

13 In an experiment in India, Khose et al. (2003) reported that the cost of broiler production per kg 

14 live weight was lowest in the group fed the diet with a 50 percent reduction in feed dicalcium 

15 phosphate supplemented with phytase. Osei et al. (2008) used an integrated economic and 

16 environmental modeling system to evaluate effectsimpacts of N- and P- based manure 

17 application rates in Texas. Results of the study indicate that edge-of-field Ttotal P losses can be 

18 reduced by about 0.8 kg/ha/year or 14 percent when manure applications are calibrated to supply 

19 all of the recommended crop P requirements from manure Ttotal P sources only versus manure 

20 applications at the recommended crop N agronomic rate. Corresponding economic 

21 effectsimpacts are projected to average a $4,800 annual cost increase per farm. 

22 3.5 Drainage System Design 

23 Reduction of nutrient loads from agricultural drainage water has elements of source control (e.g., 

24 nutrient management, crop rotations), in-field control (e.g., the drainage system), and edge-of25 field control (e.g., controlled drainage, bioreactors). Basic subsurface drainage system design 

26 consists of field or lateral drains to collect drainage from the fields, collectors or mains to collect 

27 the water from the lateral drains, and a ditch or other conveyance to convey the collected water 

28 away from the field. The size, depth, and spacing of the drains are key determinants of the 

29 drainage rate or drainage intensity (DI). 

Implementation Measure: Where subsurface drainage is added to an agricultural field, design 

the system to minimize the discharge of N through tile drains.

30 Implementation Measure: Where subsurface drainage is added to an agricultural field, 

31 design the system to minimize the discharge of nitrogen through tile drains.

32 Practice Effectiveness 

33 Subsurface Drainage System Depth and Spacing Effectiveness 

34 Several studies performed under different conditions documenthave documented significant 

35 reductions in both discharge volume and nitrate loads for shallower and more widely spaced 
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Chapter 2. Agriculture 2-84 

1 drains compared to deeper and more closely spaced drains (Table 2-2321). Neither drain spacing 

2 nor depth has been shown to have a consistent effect on nitrate concentration, however. 

3 From a detailed analysis of published field data and simulation results it was concluded that N 

4 losses increase with drainage rates or DI because of lowered water tables, increased 

5 mineralization of organic matter, reduced denitrification, and increased rates of subsurface water 

6 movement to surface waters (Skaggs, Youssef et al. 2005). Factors affecting drainage rates 

7 include drain depth, drain spacing, soil properties, hydraulic conductivity, drainable porosity, the 

8 depth of the profile through which water moves to the drains, surface depressional storage, drain 

9 diameter, drain envelopes, the size and configuration of openings in the drain tube walls, the 

10 hydraulic capacity of the drainage network to remove water from the field, and management 

11 (e.g., controlled drainage) of the drainage outlet. Additional factors affecting nitrate losses 

12 through drain tiles include climate, fertilization rate, and crop rotations.

13 In a North Carolina study of the effect of subsurface drain depth on nitrate losses from plots 

14 receiving swine wastewater applications, the shallow drainage system (0.75 m deep and 12.5 m 

15 apart) had 42 percent less outflow than the deeper drainage system (1.5 m deep and 25 m apart), 

16 and nitrate export from the shallow drains (8 kg/ha in 2001 and 27 kg/ha in 2002) was 

17 significantly (p=0.10) lower than from the deeper drains (6 kg/ha in 2001 and 37 kg/ha in 2002) 

18 in 2002, but not for the entire 21-month period (Burchell, Skaggs et al. 2005). Lower nitrate 

19 concentrations were observed in the shallow groundwater beneath the shallow drainage plots 

20 because of higher water tables and likely increased denitrification, but nitrate concentrations in 

21 the drainage water from the shallow drains increased, possibly due to preferential flow paths to 

22 the drains from the surface (hence, shorter retention times) and soil pore flushing near the 

23 shallow drains.

24 Table 2-2321. Measured effects of changes in drain depth and spacing 

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 

NO3-N 

Conc. 

NO3-N 

Load 

NC Swine 

wastewater 

applied 

Plot 0.75 12.5 1.5 25 42% -

217%a1

26%b2 Burchell, 

Skaggs et al. 

2005 

0.9 1.2 20%d4 N/S 18%d4

13 51 24%d4 N/S 23%d4

0.9 13 0.9 51 N/S 19%e548% 

MN Poorlydrained 

soils; cornsoybeanc

so

ybean3

Plot 

1.2 13 1.2 51 N/S -15%e5-1% 

Sands, Song

et al. 2008 

0.61 15.24 0.91 30.48 43%g7 N/S

eS5

37%h8

0.61 15.24 1.22 30.48 62%g7 N/S

eS5

51%h8

ILfIL6 Poorlydrained 

soils; 

soybeanscorn 

Plot 

0.91 30.48 1.22 30.48 33%g7 N/S

eS5

22%h8

Cooke, 

Nehmelman et 

al. 2002 

0.75 20 0.75 5 42%i9 N/S 44%i9

0.75 20 0.75 10 19%i9 N/S 21%i9

IN Clermont 

silt loam, 

corn for 9 

yr, then 6 

yr cornsoybean 

Plot 

0.75 10 0.75 5 28%i9 N/S 28%i9

Kladivko, 

Frankenberger

et al. 2004 

KEY: DI=drainage intensity, Q=drainage water discharge, N/S=no significant change 
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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 

NO3-N 

Conc. 

NO3-N 

Load 

Notes:

a. FOOTNOTES:

1Significant increase in 2001 (7.6 mg/L shallow vs. 2.4 mg/L deep), but not significant in 2002 (15.7 mg/L vs. 12.8 mg/L). 

b. 2Significant decrease in 2002 (27.3 kg NO3-N/ha shallow vs. 36.9 kg NO3-N/ha deep) but N/S over a 21-month period. 

c. 3Nitrate concentration (4.4 mg/L greater for corn) and load (45% greater for corn) were significantly affected by crop 

type. 

d. 4Using adjusted means. 

e. 5Flow-weighted concentrations. 

f. 6Findings based on only 1 year of monitoring data. 

g. 7Changes in cumulative flow were greater than changes in flow for discrete events. 

h. 8Similar load reductions were achieved for discrete events. 

i. 9Average of two blocks over 15 years. 

1 From a detailed analysis of published field data and simulation results it was concluded that N 

2 losses increase with drainage rates or DI because of lowered water tables, increased 

3 mineralization of organic matter, reduced denitrification, and increased rates of subsurface water 

4 movement to surface waters (Skaggs et al. 2005). Factors affecting drainage rates include drain 

5 depth, drain spacing, soil properties, hydraulic conductivity, drainable porosity, the depth of the 

6 profile through which water moves to the drains, surface depressional storage, drain diameter, 

7 drain envelopes, the size and configuration of openings in the drain tube walls, the hydraulic 

8 capacity of the drainage network to remove water from the field, and management (e.g., 

9 controlled drainage) of the drainage outlet. Additional factors affecting nitrate losses through 

10 drain tiles include climate, fertilization rate, and crop rotations.

11 In a North Carolina study of the effect of subsurface drain depth on nitrate losses from plots 

12 receiving swine wastewater applications, the shallow drainage system (0.75 m deep and 12.5 m 

13 apart) had 42 percent less outflow than the deeper drainage system (1.5 m deep and 25 m apart), 

14 and nitrate export from the shallow drains (8 kg/ha in 2001 and 27 kg/ha in 2002) was 

15 significantly (p = 0.10) lower than from the deeper drains (6 kg/ha in 2001 and 37 kg/ha in 2002) 

16 in 2002, but not for the entire 21-month period (Burchell et al. 2005). Lower nitrate 

17 concentrations were observed in the shallow groundwater beneath the shallow drainage plots 

18 because of higher water tables and likely increased denitrification, but nitrate concentrations in 

19 the drainage water from the shallow drains increased, possibly because of preferential flow paths 

20 to the drains from the surface (hence, shorter retention times) and soil pore flushing near the 

21 shallow drains.

22 Nine subsurface drainage plots in Minnesota were monitored for 5 years to investigate the role of 

23 subsurface drainage depth and DIdrainage intensity on nitrate loads to subsurface drains (Sands, 

24 Song et al. 2008). Three plots had a depth of 120 cm (conventional depth) and a spacing of 24 m, 

25 resulting in a calculated DI of 13 mm/d (conventional rate), while two plots had a depth of 90 cm 

26 and a spacing of 18 m that was calculated to also achieve the conventional DI of 13 mm/d. Two 

27 plots each had depth/spacing combinations of 120 cm/12 m and 90 cm/9 m, designed to simulate 

28 the intensification of drainage systems experienced in the area. Analysis of aggregated data 

29 showed that both shallower and less intense drain systems reduced both discharge (20 percent 

30 and 24 percent, respectively) and nitrate loading (18 percent and 23 percent, respectively), but 
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Chapter 2. Agriculture 2-86 

1 not flow-weighted nitrate Nnitrogen concentration. Interaction effects, however, indicated that 

2 intense drainage increased nitrate concentration for shallow drainage, but diluted nitrate 

3 concentrations for drains at conventional depth. Because of thatthis, nitrate loads increased 

4 significantly for shallow drainage when combined with increased DIdrainage intensity, while 

5 nitrate loads for conventional drainage depth remained at a similar level despite increased 

6 DIdrainage intensity. 

7 In a 1-year study of tile effluent from drainage tiles installed at different depths in a 16-ha field 

8 in Illinois, Cooke et al. (2002) it was found that tile discharge decreased with decreasing tile 

9 depth for tiles at 0.61m, 0.91m, and 1.22m depth (Cooke, Nehmelman et al. 2002). Cumulative 

10 discharge from the monitored tile lines at 0.61m and 0.91m depth were 43 percent and 33 percent 

11 less, respectively, than discharge from the tile line at 1.22m, and average nitrate load reductions 

12 for the 0.61m and 0.91m tile lines, when compared to the tile line at 1.22m, were 51 percent and 

13 22 percent, respectively. There was no relationship between flow-weighted nitrate concentration 

14 and tile depth, and the authors recommend that more data are required to validate the findings. 

15 A 15-yearyr drainage study in Indiana to evaluate three drain spacings (5, 10, and 20 m) installed 

16 at a depth of 0.75 m showed that both discharge and nitrate load were reduced significantly as 

17 drain spacing was increased, but that flow-weighted nitrate concentration did not vary with drain 

18 spacing (Kladivko, Frankenberger et al. 2004). Differences in nitrate loads with spacing occurred 

19 primarily during the years with continuous corn, high fertilizer N rates, and no cover crop. 
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Chapter 2. Agriculture 2-87 

1 4. Implementation Measures and Practices for Edge- of2 Field Trapping and Treatment 

3 Edge- of- field practices remediate or intercept the pollutant before or after it is delivered to the 

4 water resource, if the pollutants have not been effectively controlled at the source or in the field. 

5 Wetlands, drainage water management, and buffers and setbacks are examples of be important 

6 edge- of- field or end- of- pipe measures to prevent nutrient loads to the Chesapeake Bay. 

7 4.1 Buffers and Minimum Setbacks 

8 Buffers are described in Chapter 5 of this document.

Implementation Measure: Integrate into farm plans fertilizer application buffers or minimum 

setbacks from in-field ditches, intermittent streams, tributaries, and surface waters.

9 Buffers are described in Chapter 5 of this guidance.

10 Implementation Measure: Integrate buffers or minimum setbacks from in-field ditches, 

11 intermittent streams, tributaries and surface waters from fertilizer application into farm 

12 plan.

13 Practice Effectiveness 

14 Merriman et al. (2009) developed a compilation of BMP effectiveness results. Table 2-2422

15 presents a listing of individual results for conservation buffer practices along with percent 

16 reductions for TP, TN, and sediment. Additional data on reductions for particulate P, dissolved 

17 P, NO3-N, and ammonium are also available. 

18 Table 2-2422. TP, TN, and sedimentSediment reductions for various conservation buffer practices

19 as compiled by Merriman et al. (2009).

Reference (as 

cited by 

Merriman et 

al. 2009) State BMP name Study scale Slopes HSG 

TTotal 

P % 

TTotal 

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%
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Chapter 2. Agriculture 2-88 

Reference (as 

cited by 

Merriman et 

al. 2009) State BMP name Study scale Slopes HSG 

TTotal 

P % 

TTotal 

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 VFSVegetated Filter 

Strip

Field plot 3-8 C 2% 1% 31%

Srivastava et 

al. 1996 

Arkansas VFSVegetated Filter 

Strip

Field plot 3-8 C 65.5% 67.2%

Srivastava et 

al. 1996 

Arkansas VFSVegetated Filter 

Strip

Field plot 3-8 C 36% 43.9%

Dillaha et al. 

1988 

Virginia VFSVegetated Filter 

Strip

Field plot 8-15 C 63% 64% 87%

Feagley et al. 

1992 

Louisiana VFSVegetated Filter 

Strip

Field plot <N/A> D 78.49%

Chaubey et al. 

1995 

Arkansas VFSVegetative Filter 

Strip (15.2 m) 

Field plot 3-8 C 86.8% 75.7%

Sanderson et 

al. 2001 

Texas VFSVegetative Filter 

Strip (16.4 m) 

Field plot <N/A> C 47%

Sanderson et 

al. 2001 

Texas VFSVegetative Filter 

Strip (16.4 m) 

Field plot <N/A> C 76%

Chaubey et al. 

1995 

Arkansas VFSVegetative Filter 

Strip (21.4 m) 

Field plot 3-8 C 91.2% 80.5%

Daniels and 

Gilliam.., 1996

North 

Carolina 

VFSVegetative Filter 

Strip (3 m) 

Field 3-8 B 55% 40% 53%

Blanco-Canqui 

et al. 2004 

Missouri VFSVegetative Filter 

Strip (4 m) 

Field plot 3-8 D 77% 91%

Chaubey et al. 

1995 

Arkansas VFSVegetative Filter 

Strip (4 m) 

Field plot 3-8 C 39.6% 39.2%

Parsons et al. 

2001 

North 

Carolina 

VFSVegetative Filter 

Strip (4 m) 

Field plot <N/A> <N/A> 50% 50%

Mendez et al. 

1999 

Virginia VFSVegetative Filter 

Strip (4.3 m) 

Field plot 15-25 C 55.6% 81.9%

Dillaha et al. 

1989 

Virginia VFSVegetative Filter 

Strip (4.6 m) 

Field plot 3-8 C 85% 84% 83%

Dillaha et al. 

1989 

Virginia VFSVegetative Filter 

Strip (4.6 m) 

Field plot 8-15 C 73% 73% 86%

Dillaha et al. 

1988 

Virginia VFSVegetative Filter 

Strip (4.6 m) 

Field plot 15-25 C 52% 69% 76%

Dillaha et al. 

1989 

Virginia VFSVegetative Filter 

Strip (4.6 m) 

Field plot 15-25 C 49% 47% 53%

Daniels and 

Gilliam.., 1996

North 

Carolina 

VFSVegetative Filter 

Strip (6 m) 

Field 3-8 B 65% 48% 68%

Chaubey et al. 

1995 

Arkansas VFSVegetative Filter 

Strip (6.1 m) 

Field plot 3-8 C 58.4% 53.5%
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Chapter 2. Agriculture 2-89 

Reference (as 

cited by 

Merriman et 

al. 2009) State BMP name Study scale Slopes HSG 

TTotal 

P % 

TTotal 

N % 

Total 

sediment 

% 

Srivastava et 

al. 1996 

Arkansas VFSVegetative Filter 

Strip (6.1 m) 

Field plot 3-8 C 25.5% 21.4%

Mendez et al. 

1999 

Virginia VFSVegetative Filter 

strip (8.5 m) 

Field plot 15-25 C 81.5% 90.2%

Coyne et al. 

1995 

Kentucky VFSVegetative Filter 

Strip (9 m) 

Field plot 8-15 B 99%

Dillaha et al. 

1988 

Virginia VFSVegetative Filter 

Strip (9.1m) 

Field plot 3-8 C 19% 9% 58%

Dillaha et al. 

1989 

Virginia VFSVegetative Filter 

Strip (9.1m) 

Field plot 3-8 C 87 81% 93%

Dillaha et al. 

1988 

Virginia VFSVegetative Filter 

Strip (9.1m) 

Field plot 8-15 C 80% 80% 95%

Dillaha et al. 

1989 

Virginia VFSVegetative Filter 

Strip (9.1m) 

Field plot 8-15 C 93% 93% 98%

Dillaha et al. 

1988 

Virginia VFSVegetative Filter 

Strip (9.1m) 

Field plot 15-25 C 57% 72% 88%

Dillaha et al. 

1989 

Virginia VFSVegetative Filter 

Strip (9.1m) 

Field plot 15-25 C 65% 59% 70%

Chaubey et al. 

1995 

Arkansas VFSVegetative Filter 

Strip (9.2 m) 

Field plot 3-8 C 74% 66.6%

Source: Merriman et al. 2009

1 

2 Liu et al. (2008) performed an extensive review of sediment trapping efficiencies from more than 

3 80 representative BMP experiments. A summary of their data is presented in Table 2-2523. Their 

4 analysis of thethese data indicateindicated that regardless of the area ratio of buffer to 

5 agricultural field, a 10-m buffer and a 9 percent slope optimizeoptimized the sediment- trapping 

6 capability of vegetated buffers. 

7 Table 2-2523. Summary of VFS characteristics and corresponding sediment- trapping efficiencies

8 (source: Liu et al. 2008).

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 14.3
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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 50.89
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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. 2008
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Chapter 2. Agriculture 2-92 

1 

2 
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Chapter 2. Agriculture 2-93 

1 
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Chapter 2. Agriculture 2-94 

1 

2 
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Chapter 2. Agriculture 2-95 

1 

2 

3 Ghadiri et al. (2001) developed a set of laboratory experiments with a tilting flume to investigate 

4 the effects of buffer strips on flow hydrology and sediment transport/deposition in and around 

5 the strips. The investigators found that flow retardation initiates above the strip and can begin to 

6 remove sediment. The results summarized in Table 2-26Exhibit 5 show sediment deposition 

7 ranging from 18 to 77 percent, but caution is advised when applying thosethese laboratory results 

8 to field conditions. In a study of simulated filter strips, Jin et al. (2002) found that adding

9 addition of a mulch barrier increased the sediment trapping efficiency of filter strips by 10–-60 

10 percent compared with the same flow, slope, and filter strip conditions without mulch. The 

11 observed interactions of crop residue mulches and filter strips suggest that combining residue 

12 management systems with vegetative buffer strips containing an upslope edge of strong 

13 vegetation offer potential synergies for increased conservation effectiveness. Jin and Romkens 

14 (2001) found that over 80 percent of the sediment trapped by a vegetative or vegetated filter strip 

15 (VFS) was deposited in the approach channel to the VFS and in the upper half of the VFS, with 

16 most of the deposited sediment particles larger than 150 μmum in diameter. As the slope 

17 increased, deposition moved downstream and deposited sediment became larger. 

18 Table 2-2624. Effect of high-density grass strip

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)
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Chapter 2. Agriculture 2-96 

1 

2 

3 In a field experiment in Ontario, Gharabaghi et al. (2001) compared sediment removal efficiency 

4 using a variety of filter widths (2.44, 4.88, 9.67 and 19.52 m), flow rates, and slopes. TheyThe 

5 investigators found that sediment removal ranged from 50 to 98 percent, and generally found 

6 little improvement for widths greater than 10 m. Sediment removals are depicted in Figure 2-3. 

7 

Source: Gharabaghi et al. 2001
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Chapter 2. Agriculture 2-97 

1 Figure 2-3. Average sediment-removal efficiencySediment Removal Efficiency of VFS.Vegetative 

2 Filter Strips

3 (source: Gharabaghi et al. (2001))

4 

5 

6 

7 With the Raritan Basin in New Jersey serving as a case study, Qiu et al. (2009) compared the 

8 placement of fixed-width buffers usingbased on regulatory rules, variable-width buffers 

9 according tobased on watershed initiatives, and variable source area-based conservation buffer 

10 placement strategy derived from an alternative concept of watershed hydrology. The authors 

11 show that there is little difference in cost- effectiveness between fixed- and variable-width 

12 buffers, but that the variable source area-based buffer placement strategy (which targets the most 

13 hydrologically critical source areas in a watershed tier buffer placement) is more cost- effective. 

14 In a riparian buffer in Connecticut, one-half of a 35 m x 250 m riparian buffer cropped in corn 

15 was seeded with fine- leaf fescue and allowed to remain idle (Clausen et al. 2000). TKN and TP 
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Chapter 2. Agriculture 2-98 

1 concentrations significantly (p P < 0.05) increased as groundground water flowed through the 

2 restored buffer, while nitrate concentrations declined significantly with most (52 percent) of the 

3 decrease occurring within a 2.5-m wetland adjacent to the stream. An N mass balance for the 

4 2.5-m strip indicated that denitrification only accounted for only 1 percent of the N losses and 

5 plant uptake accounted for 7– to 13 percent of the N losses annually. GroundGround water was 

6 the dominant source of N to the buffer and also the dominant loss pathway. Restoration of the 

7 riparian buffer decreased (p < 0.05) overland flow concentrations of TKN by 70 percent, NO3-N 

8 by 83 percent, TP by 73 percent, and TSS by 92 percent as compared with the control. 

9 Restoration reduced (p < 0.05) NO3-N concentrations in groundground water by 35 percent as 

10 compared with the control. Underestimated denitrification and dilution by upwelling ground 

11 water in the wetland area adjacent to the stream were believed to be primarily responsible for the 

12 decreasing NO3-N concentrations observed. 

13 In a plot stuidy, Dosskey et al. (2007) examined whether filter strip effectiveness changes over 

14 years since establishment and if temporal change depends on vegetation type. Plots containing 

15 all-grass (New Grass) and grass with trees and shrubs (New Forest) were established in 1995 

16 among plots that contained either grass since 1970 (Old Grass) or were re-cultivated and re17 planted annually with grain sorghum (Crop). Once each summer, in 1995, 1996, 1997, 2003, and 

18 2004, identically prepared solutions containing sediment, N and P fertilizer, and bromide tracer 

19 were applied to the upper end of each plot during a simulated rainfall event. The authors 

20 concluded that filter strip performance improves over a period of years since establishment, with 

21 most of the change occurring within three growing seasons after establishment. Infiltration 

22 characteristics account for most of that change, and grass and forest vegetation are equally 

23 effective as filter strips for at least 10 growing seasons after establishment. 

24 Lee et al. (2003) used a field plot study to determine the effectiveness of an established multi25 species buffer in trapping sediment, Nnitrogen, and P phosphorus from cropland runoff during 

26 natural rainfall events. A switchgrass buffer removed 95 percent of the sediment, 80 percent of 

27 the N, 62 percent of the nitrate-nitrogen (NO3-N), 78 percent of the P, and 58 percent of the 

28 phosphate-phosphorus (PO4-P), while a switchswitch grass/woody buffer removed 97 percent of 

29 the sediment, 94 percent of the TNtotal-N, 85 percent of the NO3-N, 91 percent of the TPtotal-P, 

30 and 80 percent of the PO4-P in the runoff. In an earlier study using the same plots, Lee et al. 

31 (2000) found generally similar results; during a 2-hourhr rainfall simulation at 25 mm/h, the 

32 switchgrass buffer removed 64, 61, 72, and 44 percent of the incoming Ttotal N, NO3-N, Ttotal 

33 P, and PO4-P, respectively. The switchswitch grass-woody buffer removed 80, 92, 93, and 85 

34 percent of the incoming Ttotal N, NO3-N, Ttotal P, and PO4-P, respectively. During a 1-hour 

35 rainfall simulation at 69 mm/h, the switchgrass buffer removed 50, 41, 46, and 28 percent of the 

36 incoming Ttotal N, NO3-N, Ttotal P, and PO4-P, respectively, The switchgrass-woody plant 

37 buffer removed 73, 68, 81, and 35 percent of the incoming Ttotal N, NO3-N, Ttotal P, and PO4-P, 

38 respectively. In both studies, the switchgrass buffer was effective in trapping coarse sediment 

39 and sediment-bound nutrients, but the additional buffer width with high infiltration capacity 

40 provided by the deep-rooted woody plant zone was effective in trapping the clay and soluble 

41 nutrients. 

42 Using a set of 36 field lysimeters with six different ground covers (bare ground, orchardgrass, 

43 tall fescue, smooth bromegrass, timothy, and switchgrass), Lin et al. (2007) evaluated the ability 

44 of grasses to reduce nutrient levels in soils and shallow groundwater. The leachate from each 
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Chapter 2. Agriculture 2-99 

1 lysimeter was collected after major rainfall events during a 25-day period, and soil was collected 

2 from each lysimeter at the end of the 25-day period. Grass treatments reduced NO3-N levels in 

3 leachate by 74.5 to 99.7 percent compared to the bare ground control, but timothy was 

4 significantly less effective at reducing NO3-N leaching than the other grasses. Switchgrass 

5 decreased PO4-P leaching to the greatest extent, reducing it by 60.0 to 74.2 percent compared to 

6 the control. In a separate study, Bedard-Haughn et al. (2005) found that cutting vegetative 

7 buffers increased the uptake of NO3-N 2.3 times that of uncut buffers. 

8 The influence of vegetation characteristics, buffer width, slope, and stubble height on sediment 

9 retention was evaluated in a Montana study using three vegetation types (sedge wetland, rush 

10 transition, bunchgrass upland) on plots spanning 2 to 20 percent slopes (Hook, 2003). Sediment 

11 retention was affected strongly by buffer width and moderately by vegetation type and slope, but 

12 it was not affected by stubble height. Mean sediment retention ranged from 63 to > 99 percent 

13 for different combinations of buffer width and vegetation type, with 94 to 99 percent retention in 

14 6-m-wide buffers regardless of vegetation type or slope. Results suggest that rangeland riparian 

15 buffers should be at least 6 m wide, with dense vegetation, to be effective and reliable. 

16 Mankin et al. (2007) studied the effectiveness of established grass-shrub riparian buffer systems 

17 in reducing TSS, P, and N using simulated runoff on nine plots with widths ranging from 8.3 to 

18 16.1 m. Vegetation types were all natural selection grasses (control), a 2-segment buffer with 

19 native grasses and plum shrub, and a 2-segment buffer with natural selection grasses and plum 

20 shrub. Removal efficiencies were strongly linked to infiltration, with TSS mass and 

21 concentration reductions averaging 99.7 percent and 97.9 percent, TP reductions of 91.8 percent 

22 and 42.9 percent, and TN reductions at 92.1 percent and 44.4 percent. Mankin et al. (2007) 

23 concluded that adequately designed and implemented grass-shrub buffers with widths of 8 m 

24 provide for water quality improvement, particularly if adequate infiltration is achieved. 

25 Hoffman et al. (2009) examined the main hydrological pathways for P losses from and P 

26 retention in riparian buffers. They determined that P retention rates of up to 128 kg P/ha-yr 

27 canmay be accounted for by sedimentation, while plant uptake canmay temporarily immobilize 

28 up to 15 kg P/ha-yr. Dissolved P retention is often below 0.5 kg P/ha-yr, and the authors note 

29 that several studies have shown significant release of dissolved P up to 8 kg P/ha-yr. 

30 In Finland, the effects of 10-m– wide, annually cut grass buffer zones (GBZ) and vegetated 

31 buffer zones under natural vegetation (VBZ) were compared on 70-m- long x 18-m- wide plots 

32 with no buffer zone (Uusi-Kamppa 2006). Retention of TS, TP and PP was > 50, 40, and > 45 

33 percent, respectively, for both treatments. 

34 In northeast Italy, a 5-m- wide grass strip and a 1-m wide row of trees were evaluated with corn 

35 and wheat from 1997 to- 1999 (Borin and Bigon 2002). Under a variety of fertilization levels and 

36 tree sizes, water discharged from the strip was always below 2 ppm. Tree size showed no evident 

37 effect on the reduction of the concentration. In a companion study from 1998 to -2001, Borin et 

38 al. (2005) evaluated 6-m buffer strips with adjoining fields of corn-wheat-soybeans. The buffer 

39 strip was composed of two rows of regularly alternating trees and shrubs, with grass in the inter40 rows. Total runoff was reduced by 78 percent. TSS concentrations at the control was 2–-7 times 

41 greater than the TSS of 0.14 mg/L from the buffer strip. N concentrations through the buffer strip 

42 were higher than control, but mass loadings were reduced from 17.3 to 4.5 kg/ha. 
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Chapter 2. Agriculture 2-100 

1 4.2 Wetlands 

Implementation Measure: Protect and restore wetlands and riparian areas from adverse effects 

and maintain such nonpoint source abatement function while protecting other existing functions 

of the wetlands and riparian areas as measured by characteristics such as vegetative composition 

and cover, hydrology of surface water and groundwater, geochemistry of the substrate, and 

species composition.

2 Implementation measure: Protect and restore wetlands and riparian areas from adverse 

3 effects and maintain this nonpoint source abatement function while protecting other 

4 existing functions of these wetlands and riparian areas as measured by characteristics such 

5 as vegetative composition and cover, hydrology of surface water and ground water, 

6 geochemistry of the substrate, and species composition. 

7 Properly functioning natural wetlands and riparian areas (Chapter 5) can significantly reduce 

8 nonpoint source pollution by intercepting surface runoff and subsurface flow and by settling, 

9 filtering, or storing sediment and associated pollutants. Wetlands and riparian areas typically 

10 occur as natural buffers between uplands and adjacent waterwater bodies. Loss of suchthese

11 systems allows a more direct contribution of nonpoint source pollutants to receiving waters. 

12 Degraded wetlands and riparian areas canmay even become pollutant sources. Thus, natural 

13 wetlands and riparian areas should be protected and should not be used as designated erosion 

14 control practices. Their nonpoint source control functions are most effective as part of an 

15 integrated land management system focusing on nutrient, sediment, and erosion control practices 

16 applied to upland areas. 

17 Protection of the full range of functions for wetlands and riparian areas are discussed in National 

18 management measures to protect and restore wetlands and riparian areas for the abatement of 

19 nonpoint source pollution (USEPA, 2005). Protection of wetlands and riparian areas should 

20 allow for both nonpoint source pollution control and maintenance of other benefits of these 

21 natural aquatic systems, e.g., wildlife habitat. 

22 Examples of implementation practices for protecting wetlands and riparian areas include the 

23 following: 

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

25 source NPS control potential when implementing NPS management practices. 

26 • Do not alter wetlands or riparian areas to improve their water quality functions at the 

27 expense of their other functions. 

28 • Use appropriate preliminary treatment practices such as vegetated treatment systems or 

29 detention or retention basins to prevent adverse effects on impacts to wetland functions 

30 that affect nonpoint sourceNPS pollutant abatement from hydrologic changes, 

31 sedimentation, or contaminants. 

32 Wetlands and their functions related to reducing transport of agricultural pollutants are described 

33 in existing guidance (USEPA, 2003). 
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Chapter 2. Agriculture 2-101 

1 Practice Effectiveness 

2 Fisher and Acreman (2004) gathered data from 57 wetlands from around the world to evaluate 

3 nutrient removal efficacy. Table 2-27 25 displays a list of those wetlands, and FigureTable 2-48

4 displays the removal efficiencies for Nnitrogen and phosphorous as a function of loading—note 

5 that the trend for Nnitrogen is statistically significant while the regression line for Pphosphorus is 

6 not. 

7 Table 2-2725. Summary of wetlands wetland evaluated

Summary of references studied showing wetland name, wetland type. (Fisher and country of location. References are 

split into those showing an increase in nutrient loading, decrease in nutrient loading and those showing 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 NO3 Unknown Riparian USA

Cooper and Gilliam 1987 P Unknown Riparian USA

Lowrance et al. 1984 NO3 Unknown Riparian USA

Cooke 1994 P, NO3 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 NO3, NO4 Kismeldon Meadows and 

Bradford Mill

Riparian UK

Peterjohn and Correll 1984 sol P Rhode River drainage basin Riparian USA

Jordan et al. 1993 NO3, TP Chester River catchment Floodplain USA

Gehrels and Mulamootth 1989 TP Unknown Marsh/swamp USA

Burt el al. 1998 NO3 R. Leach floodplain Floodplain UK

Haycock and Burt 1993 NO3 R. Leach floodplain Floodplain UK

Cooper 1994 NO3 Unknown Swamp NZ

Prior 1998 N, P R. Lambourn floodplain Floodplain UK

Haycock and Pinay 1993 NO3 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, NH4 Waigani Marsh/swamp Papua N. Guinea

Cooper 1990 NO3 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 NO3 Unknown Riparian Spain

Mander et al. 1997 N, P Porijogi River catchment Riparian Estonia

Downes et al. 1997 NO3 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 USA
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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 P04 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 P04 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, NO3 Unknown Riparian USA

Dorge 1994 NO3 Rabis Baek Peatland Denmark

Dorge 1994 NO3 Syvbaek Riparian Denmark

Dorge 1994 NO3 Glumso Marsh/swamp Denmark

Schlosser and Karr 1981 TP Champaign-Urbana Riparian USA

Hanson et al. 1994 NO3 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 NO3 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 NO2, NO3 Waigani Marsh/swamp Papua N. Guinea

Downes et al. 1997 NO3, 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, PO4 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 particulate N, PN = particulate N, PO4 = orthophosphate, NO3 = nitrate, NO2 
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Author(s) Date N or P Wetland name Wetland type Country

= nitrate and NH4 = ammonium, including ammonium-N.

1 

Source: Fisher and Acreman 2004

2 
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1 

2 
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1 

2 
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1 

2 Figure 2-4. Percent nutrient reduction as a function of loading. (source: Fisher and Acreman, 

3 2004)

4 
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1 

2 

3 On Kent Island, Maryland, a 1.3- ha restored wetland receives the unregulated inflows from a 

4 14--ha agricultural watershed (Jordan et al. 2003). Most nutrient removal occurred in the first 

5 year, which included a 3three-month period of decreasing water level in the wetland. In that year, 

6 the wetland removed 59 percent of the TPtotal P, 38 percent of the TNtotal N, and 41 percent of 

7 the total organic carbon (TOC)C it received. However, in the second year, which lacked a drying 

8 period, there was no significant (p > 0.05) net removal of Ttotal N or P, although 30 percent of 

9 the TOtotal organic C input was removed. For the entire 2-year period, the wetland removed 25 

10 percent of the ammonium, 52 percent of the nitrate, and 34 percent of the organic carbonC it 

11 received, but there was no significant net removal of TSS or other forms of N and P. 

12 A wetland mesocosm experiment was conducted in eastern North Carolina to determine if 

13 organic matter (OM) addition to soils used for in-stream constructed wetlands would increase 

14 NO3-N treatment (Burchell et al. 2007). Four batch studies, with initial NO3-N concentrations 

15 ranging from 30 to 120 mg/L, were conducted in 2002 in 21 surface-flow wetland mesocosms. 

16 The results indicated that increasing the OM content of a Cape Fear loam soil from 50 g/kg to 

17 110 g/kg enhanced NO3-N wetland treatment efficiency in spring and summer batch studies, but 

18 increases to 160 g/kg OM did not. Increased OM addition and biosolids to the Cape Fear loam 

19 significantly increased biomass growth in the second growing season when compared to no OM 

20 addition. ThatThis research indicates that increased OM in the substrate will reduce the area 

21 required for in-stream constructed wetlands to treat drainage water in humid regions. 
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Chapter 2. Agriculture 2-108 

1 A small-scale wetland system was constructed and monitored for several years in order to 

2 quantify nutrient removal near Steamboat Creek, a tributary of the Truckee River in Nevada 

3 (Chavan et al. 2007). Results indicated seasonal variations in nutrient removal with 40–-75 

4 percent of TNtotal nitrogen and 30–-60 percent of TPtotal phosphorus being removed, with 

5 highest removals during summer and lowest removals during winter. In a following study to 

6 evaluate the effectiveness of a large-scale wetland, 10ten parallel pilot-scale wetland mesocosms 

7 were used to test the effects of drying and rewetting, hydraulic retention time (HRT), and high 

8 Nnitrogen loading on the efficiency of nutrient and total suspended solids (TSS) removal 

9 (Chavan et al. 2008). During increased influent Nnitrogen loading (9.5 +/- 2.4 mg/L), 

10 manipulated mesocosms functioned as sinks for total nitrogen (TN) with removal efficiency 

11 increasing from 45 45 +/- 13 percent to 87 +/- 9 percent. The average change in TN 

12 concentration was 9.1 +/- 2.2 mg/L. TP removal was associated with TSS removal. 

13 Wetlands dominated by submerged aquatic vegetations (SAVs) canmay take up nutrients, 

14 particularly phosphorus (P), from surface flow with high efficiency. In a 1999–-2001 study in 

15 South Florida, samples were collected from four small constructed test cells (wetlands) (Gu 

16 2008). Test cells receiving higher TP (average = 75 μgug/L) displayed a removal efficiency of 

17 60 percent while test cells receiving lower TP (average = 23 μgug/L) had a 20 percent removal 

18 efficiency. In a similar study, Gu and Dreschel (2008) evaluated the effectiveness of constructed 

19 wetlands from 2002–-2004. Test cells receiving higher TP (average = 72 μgug/L) displayed a 

20 removal efficiency of 56–-65 percent while test cells receiving lower TP (average = 43 μgug/L) 

21 had a 35–-62 percent removal efficiency with a hydraulic loading rate of 9.27 in/yr. 

22 The restoration plan for the Everglades includes construction of large stormwater treatment areas 

23 (STAs) to intercept and treat this relatively high nutrient water down to very low total P (TP)

24 concentrations (White et al. 2006). One such STA has been in operation for approximately 10 

25 yearsyr and contains both emergent aquatic vegetation (EAV) and submerged aquatic vegetation 

26 (SAV) communities. The authors investigated the interaction of vegetation type (EAV or SAV) 

27 and hydrology (continuously flooded or periodic drawdown) on the P removal capacity in 

28 mesocosms packed with peat soil obtained from STA-1W. The surface water had low TP 

29 concentrations with an annual mean of 23 μgug/L. For SRsoluble reactive P and TP, hydrologic 

30 fluctuations had no discernable effectimpact on P treatment while vegetation type showed a 

31 significant effectimpact. Influent SRsoluble reactive P decreased by 49 percent for the SAV 

32 treatments compared with 41 percent for the EAV treatments, irrespective of hydrology 

33 treatment. The reduction of dissolved organic P was also higher for the SAV treatment, 

34 averaging 33 percent, while showing a reduction of 11 percent for the EAV treatments. There 

35 was no significant difference in the treatment efficiency of particulate P across the treatments. 

36 The SAV treatments removed 45 percent of TP while EAV removed significantly less at 34 

37 percent of TP. By mass calculations, the EAV required 85 percent more P for plant growth than 

38 was removed from the water column in 1 yearyr compared with only 47 percent for the SAV. 

39 Therefore, the EAV mined substantially more P from the relatively stable peat soil, translocating 

40 it into the detrital pool. 

41 In an examination of benefits to water quality provided by a natural, flow-through wetland and a 

42 degraded, channelized wetland situated within the flood-irrigation agricultural landscape of the 

43 Sierra Nevada foothills of northernNorthern California, Knox et al. (2008) it was found that the 

44 non-degraded, reference wetland significantly improved water quality by reducing loads of 
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Chapter 2. Agriculture 2-109 

1 TSStotal suspended sediments, nitrate, and E.scherichia coli on average by 77, 60, and 68 

2 percent, respectively (Knox et al. 2008). Retention of TN, Ttotal N, total P, and soluble reactive 

3 P (SRP) was between 35 and 42 percent of loads entering the reference wetland. Retention of 

4 pollutant loads by the channelized wetland was significantly lower than by the reference wetland 

5 for all pollutants except SRP. A net export of sediment and nitrate was observed from the 

6 channelized wetland. Decreased irrigation inflow rates significantly improved retention 

7 efficiencies for nitrate, E., coli, and sediments in the reference wetland. It is suggested that 

8 maintaining suchmaintenance of these natural wetlands and regulating regulation of inflow rates 

9 can be important aspects of a BMPbest management plan to improve water quality in runoff 

10 from irrigated pastures. 

11 4.3 Drainage Water Management 

12 Subsurface drainage is a water management practice that is commonly used on many highly 

13 productive fields in areas such as the Atlantic Coastal Plain and the Midwest, but because nitrate 

14 carried in drainage water can contribute to water quality problems in the Chesapeake Bay (as 

15 well as some other waterbodies such as the Gulf of Mexico), strategies are needed to reduce the 

16 nitrate loads while maintaining adequate drainage for crop production (Frankenberger, et al. 

17 2006). Drainage is generally achieved with open ditches or buried pipe accompanied by either 

18 gravity-based or pumped outlets. Practices that can reduce nitrate loads on tile-drained soils 

19 include (Frankenberger, et al. 2006) the following: 

20 • Fine-tuned fertilizer application rates and timing,

21 • Winter forage or cover crops,

22 • Controlled drainage and water table management,

23 • Ditch management,

24 • Bioreactors to treat drainage water, and

25 • Constructed wetlands.

26 Fertilizer management and cover crops are addressed in this document under the heading 

27 nutrient management, whereas the other practices are addressed here. In addition, irrigation 

28 tailwater recovery systems are not included in this document. 

29 Controlled drainage, is simply the control of surface and subsurface water through use of 

30 drainage facilities and water control structures. Water table management is any combination of

31 the management, control, and/or regulation of soil-water conditions in the profile of agricultural 

32 soils through the use of water management structures (e.g., subsurface drains, water control 

33 structures, and water conveyance facilities) and strategies designed specifically for the given site 

34 conditions (Brown 1997). Graded ditches are used to collect or intercept excess surface or 

35 subsurface water and convey it to an outlet (USDA-NRCS 2008). Ditch management includes 

36 managingmanagement of clean-outs and vegetation within the ditch. Bioreactors are one form of 

37 edge-of-field treatment of drainage water in which the drainage is diverted into a trench filled 

38 with wood chips (Minnesota DepartmentDept. of Agriculture No dateUndated). Constructed 

39 wetlands are constructed, shallow, earthen impoundments containing hydrophytic vegetation 

40 designed to treat both point and nonpoint sources of water (USDA-NRCS 2002). 
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Chapter 2. Agriculture 2-110 

1 In drainage water management, a water control structure in a main, submain, or lateral drain is 

2 used to manipulate the depth of the drainage outlet (Frankenberger, et al. 2006). The water table 

3 must rise above the outlet depth for drainage to occur, as illustrated in Figure 2-5. The outlet 

4 depth, as determined by the control structure, is:

5 • Raised after harvest to limit drainage outflow and reduce the delivery of nitrate to ditches 

6 and streams during the off-season. (1 in Figure 2-5) 

7 • Lowered in early spring and again in the fall so the drain can flow freely before field 

8 operations such as planting or harvest. (2 in Figure 2-5) 

9 • Raised again after planting and spring field operations to create a potential to store water 

10 for the crop to use in midsummer. (3 in Figure 2-5) 

11 

12 
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1 

Figure 2-5. Drainage Control Structure Source: (Frankenberger, et al. 2006; used with permission)

2 Figure 2-5. Drainage control structure.

Implementation Measure: For both new and existing subsurface drainage systems, use 

controlled drainage, ditch management, and bioreactors as necessary to minimize off-farm 

transport of nutrients.

3 Implementation Measure: For both new and existing subsurface drainage systems, use 

4 controlled drainage, ditch management, and bioreactors as necessary to minimize off-farm 

5 transport of nutrients.

6 Practice Effectiveness 

7 Controlled Drainage and Water Table 2-Management Practice Effectiveness 

8 Numerous studies of the effects of controlled drainage have been conducted in North Carolina, 

9 the Midwest, and Canada (Table 2-2826). Flashboard riser-type water level control structures 

10 installed in tile mains or outlet ditches on moderately well-drained soils in the Coastal Plain of 

11 North Carolina reduced nitrate movement through the ditches by 80–-95 percent (from 25–40 

12 kg/ha to 1–7 kg/ha) because of due to a reduction in effluent volume with no indication of 

13 increased denitrification in the field (Gilliam, Skaggs et al. 1979). In poorly-drained soils, a 50 

14 percent reduction in nitrate movement through the drainage ditches was attributed to increased 

15 water movement into and through deeper soil horizons (below 1 m) where denitrification 

16 occurred. 

17 Variability in the effectiveness of controlled drainage is reflected in two modeling studies in the 

18 coastal plain of North Carolina. In one study, it was assumed that controlled drainage reduced N 

19 by 40 percent, but only if the slope in the channel is less than 1 percent and where the water table 

20 can be kept within 0.9 mmeters of the soil surface for 50 percent of the field area (Wossink and 

21 Osmond 2001). Long-term modeling of Core Creek using the DRAINMOD-N model after 

22 calibration on a field-by-field basis with monitoring data from 4.5 years indicated that controlled 

23 drainage could reduce nitrate loads by 10–-12 percent, and a combination of controlled drainage 

24 and nutrient management could reduce nitrate loads by 25–-33 percent (Smeltz, Evans et al. 

25 2005). Modeling predicted that controlled drainage would reduce the drainage outflow by 21.3 
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Chapter 2. Agriculture 2-112 

1 percent annually versus conventional drainage (accounting for 11.5 percent of the reduction in 

2 NO3-N leaving the watershed), and that there was a potential for 30 percent and 75 percent 

3 nitrate reductions for cotton or soybeans, respectively, as compared to corn.

4 Table 2-2826. Measured effectiveness of controlled drainage 

Reduction vs. reference practice

Location 

Soils and 

crops 

Study 

type Practice 

Reference 

practice Discharge

NO3-N 

conc. 

NO3-N 

load Source 

NC 

Moderately 

well drained 

soils 

Field 

CDflashboard 

riser 

UD 85% 85%a1 Gilliam, Skaggs et 

al. 1979 

NC Poorly drained 

soils Field 

CDflashboard 

riser 

UD 50% 50%b2 Gilliam, Skaggs et 

al. 1979 

IL Field CD UD ≤47%c3 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%d4

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%d4

36% NgNG, Tan et al. 

2001 

Ontario, 

Canada 

Corn, 

soybeans Plot CDS UD 36% 14%d4

27%e5 Tan, Drury et al. 

2003 

Ontario, 

Canada Sandy loam Field CDS UD 0% 38%d4

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%f6

Corn (200 kg 

N/ha)-soybean 

(50 kg N/ha), 

clay loam 

Field CD UD 31%f6

Drury, Tan et al. 

2009 

Corn (150 kg 

N/ha)-soybean 

(no N), clay 

loam 

Field CDS UD 66%f6

Ontario, 

Canada 

Corn (200 kg 

N/ha)-soybean 

(50 kg N/ha), 

clay loam 

Field CDS UD 68%f6

Drury, Tan et al. 

2009 

CDS - .05 m UD –-555% to 

58%g,h7,8

61%–%-

84%g7

0%–-

94%g,i7,9 Ontario, 

Canada 

Silt loam, Cornsoybean stripcropping 

Field 

CDS - .075m UD –-583% to –

-70%g,h7,8

52%–%-

77%g7

0%–-

30%g,i7,9

Mejia and 

Mandramootoo 

1998 

NC Various 

Reviewj

Review1

0 

CD UD 30%k,l11,12 ≤20%l,m12,

13 45%l,n12,14 Evans, Gilliam et 

al. 1996 
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Reduction vs. reference practice

Location 

Soils and 

crops 

Study 

type Practice 

Reference 

practice Discharge

NO3-N 

conc. 

NO3-N 

load Source 

Various Various 

Reviewj

Review1

0

CD UD 50% Appelboom and 

Fouss 2006 

Various Various 

Reviewj

Review1

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; no change in NO3-N concentration. 

b.2 Reductions due to increased penetration to deeper soil horizons where denitrification occurred. 

c. 3Nitrate load reductions due mostly to discharge reductions. Phosphate load reductions of up to 83% 

d. 4Flow-weighted mean 

e. 5Also reduced dissolved organic (47%) and dissolved inorganic (54%) P loads 

f. TN

g. 6Total N

7Monitoring only during growing season (April/May-November). 

h. 8Increased discharge due to lack of management, subirrigation, and high rainfall, resulting in little storage for rainfall 

under CDS. 

i. 9No significant difference in 1995 (0%), but significant difference in 1996 (94%, 30%). 

j. 10Reviews include some of the field and plot studies shown. 

k. 11When managed year-around; <15% reduction during growing season. 

l. 12Varies with soil type, rainfall, type of drainage, and management intensity 

m. 13TKN concentration increases slightly. Decreases P concentration for surface drainage systems, but increases P 

concentration for subsurface systems. 

n. 14NO3-N + TKN; TP reduced by 35% 

1 

2 Studies in the Midwest measured similar nitrate load reductions due to controlled drainage. A 

3 review of subsurface drainage in the Midwest revealed that drainage water management has 

4 achieved load reductions of up to 47 percent and 83 percent for nitrate and phosphate, 

5 respectively (Kalita, Cooke et al. 2007). In a replicated field plot experiment to examine the 

6 hydrology, water quality, and crop yield effectsimpacts of controlled drainage, uncontrolled 

7 drainage, and subirrigation drainage on Hoytville silty clay soil in Ohio, it was found that 

8 controlled drainage during the non-growing season reduced annual flows by 40 percent, yielding 

9 a 45 percent reduction in annual nitrate loads from a corn-soybean production system (Fausey 

10 2005). 

11 In a 3three-year study on Nicollet loam and silt-loam soils in Iowa, water-table depths of 0.3, 

12 0.6, and 0.9 m were maintained in field lysimeters at one site, and water-table depths averaging 

13 0.2, 0.3, 0.6, 0.9, and 1.1 m were maintained at a second site to determine the effects of 

14 controlled drainage-subirrigation (CDS) on nitrate concentrations in groundwater (Kalita and 

15 Kanwar 1993). The lowest nitrate concentrations in groundwater were observed under the 

16 shallow water-table depths, with nitrate concentrations in groundwater generally decreasing with 

17 increased depths, but average corn yields were 30 percent lower under the shallow water-table 

18 depths of 0.2 to 0.3 m compared to depths of 0.9 to 1.1 m. 
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1 A fairly large number of studies were conducted in Ontario, Canada, to determine the water 

2 quality and yield benefits of controlled drainage systems. In a 3-year evaluation of controlled 

3 drainage-subirrigation (CDS), conservation tillage, and corn production practices, annual tile 

4 drainage volumes were reduced by 24 percent with CDS compared with traditional drainage 

5 (UD) (Drury, Tan et al. 1996). Flow-weighted mean nitrate concentration and average annual 

6 nitrate loss in tile drainage water were reduced by 25 percent and 43 percent, respectively, when 

7 using CDS (7.9 mg/L N, 14.6 kg/ha N) instead of UD. The combination of conservation tillage 

8 and CDS reduced annual nitrate losses by 49 percent (11.6 kg/ha N) when compared with 

9 conventional moldboard plow tillage and UD. Most (88-95 percent) of the nitrate losses from all 

10 treatments occurred in the non-cropping period from November through April. The increase in 

11 nitrate loss through surface runoff for CDS (1.9 kg/ha N) compared to UD (1.4 kg/ha N) was less 

12 than 5 percent of the decrease in loss through tile drainage. 

13 Measurements from a plot study on a sandy loam soil in Southwestern Ontario, Canada, showed 

14 an 8 percent greater cumulative drainage water volume from the CDS treatment versus the free15 tile drainage (UD) treatment, but a 41 percent lower flow-weighted mean nitrate concentration 

16 (11.3 mg/L N versus 19.2 mg/L N), a 36 percent lower nitrate load (36.8 kg/ha N versus 57.9 

17 kg/ha N), and a 64 percent greater average corn yield (11.0 Mg/ha versus 6.7 Mg/ha) for CDS 

18 versus UD (Ng, Tan et al. 2001). 

19 A plot study of a wetland-reservoir system for controlled drainage and subirrigation in 

20 southwestern Ontario found that a CDS controlled drainage/sub-irrigation system (CDS) reduced 

21 drainage volume by 36 percent, flow-weighted mean nitrate concentration in tile drainage water by 

22 14 percent, total nitrate loss by 27 percent (46.3 kg N/ha versus 63.6 kg N/ha), dissolved organic P 

23 by 47 percent, and dissolved inorganic P by 54 percent compared to a free drainage system (UD) 

24 (Tan, Drury et al. 2003). Tile drainage water and surface runoff water from agricultural fields were 

25 routed into a wetland reservoir, and then recycled back through the CDS to provide subsurface 

26 irrigation during times of crop water deficit. Nitrate uptake by plants and algae in the reservoir and

27 increased corn (91 percent) and soybean (49 percent) yields contributed to the reductions in nitrate 

28 loss for the CDS system. 

29 In a comparison of CDS and UD on a 4-ha farm-scale field, CDS did not change total discharge 

30 but reduced flow-weighted mean nitrate concentration in tile drainage water by 38 percent, 

31 reduced total nitrate load by 37 percent, and increased both tomato (11 percent) and corn (64 

32 percent) yield compared to UD (Tan, Drury et al. 2004). During the same period on a 0.4-ha 

33 plot-scale field, CDS reduced total tile drainage volume by 50 percent, reduced flow-weighted 

34 mean nitrate concentration in tile drainage water by 32 percent, reduced total nitrate load by 66 

35 percent, and increased both soybean (17 percent) and corn (9 percent) yield relative to UD. 

36 A study comparing both CD and CDS versus UD at two fertilization rates (N1: 150 kg N/ha 

37 applied to corn, no N applied to soybean; N2: 200 kg N/ha applied to corn, 50 kg N/ha applied to 

38 soybean) on a clay loam soil in Ontario, Canada, documented that CD and CDS reduced N loads 

39 from tile drainage by 44 and 66 percent, respectively, relative to UD at the N1 rate, and by 31 

40 and 68 percent, respectively, at the N2 rate (Drury, Tan et al. 2009). The N concentrations in tile 

41 flow events with the UD treatment exceeded Ontario’s provisional long-term aquatic life limit 

42 for freshwater (4.7 mg N L-1) 72 percent and 78 percent of the time at the N1 and N2 rates, 

43 respectively, but only 24 percent and 40 percent, respectively, with CDS. Crop yields from CDS 
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Chapter 2. Agriculture 2-115 

1 were increased by an average of 2.8 percent relative to UD at the N2 rate, but were reduced by 

2 an average of 6.5 percent at the N1 rate. 

3 A CDS system managed at a depth of 0.050 m reduced total drain discharge over two growing 

4 seasons by 42 percent versus UD in a field study in eastern Ontario (Mejia and Mandramootoo 

5 1998). Growing-season mean nitrate concentrations in drainage water were reduced by CDS at 

6 both a depth of 0.050 m (61–-84 percent) and a depth of 0.075 m (52–-75 percent) versus UD. 

7 Because of high rainfall and failure to manage the CDS under the wet conditions, discharge was 

8 over 5 times greater in 1995 under CDS at each depth, resulting in no significant change in 

9 nitrate load. In 1996, however, growing-season nitrate loads were reduced by 94 percent and 30 

10 percent by the 0.050 m and 0.075 m CDS, respectively. 

11 Monitoring over 2 years of four replicate plots each of surface runoff, CD at 1.1m below the soil 

12 surface, and CDS at 0.8 m in Baton Rouge showed that 67 percent of the annual nitrate loss in 

13 tile drainage for the CD and CDS systems occurred during the 150-day growing season (Grigg, 

14 Southwick et al. 2003). There were no statistical differences between the surface, subsurface, or 

15 total nitrate loads from the CD and CDS systems. 

16 Compilations and reviews of literature on controlled drainage have yielded largely consistent 

17 findings. Based on approximately 125 site-years of data collected at 14 locations in eastern North 

18 Carolina (Evans, Gilliam et al. 1996): 

19 • Controlled drainage, when managed all year, reduces total outflow by approximately 30 

20 percent compared to uncontrolled systems, although outflows vary widely depending on 

21 soil type, rainfall, type of drainage system and management intensity. For example, control 

22 only during only the growing season typically reduces outflow by less than 15 percent. The 

23 effect of controlled drainage on peak outflow rates varies seasonally. Drainage control 

24 reduces peak outflow rates during dry periods (summer and fall) but canmay increase peak 

25 outflow rates during wet periods (winter and spring), depending on the control strategy. 

26 • Drainage control has little net effect on TNtotal nitrogen and Pphosphorus concentrations 

27 in drainage outflow. Controlled drainage canmay reduce NO3-N concentrations in 

28 drainage outflow by up to 20 percent , but total Kjeldahl nitrogen (TKN) concentrations 

29 are somewhat increased. Controlled drainage tends to decrease Pphosphorus

30 concentrations on predominately surface systems but has the opposite effect on 

31 predominately subsurface systems. Seasonal variations canmay also occur, depending on 

32 rainfall, soil type, and the relative contribution of surface or subsurface drainage to total 

33 outflow. 

34 • Controlled drainage reduces Nnitrogen and Pphosphorus transport at the field edge, 

35 primarily because of the reduction in outflow volume. In 14 field studies, drainage 

36 control reduced the annual transport of TNtotal nitrogen (NO3-N and TKN) at the field 

37 edge by 10 kg/ha, or 45 percent , and TPtotal phosphorus by 0.12 kg/ha, or 35 percent. 

38 Again, the reductions at individual sites were influenced by rainfall, soil type, type of 

39 drainage system, and management intensity. 

40 In a broader review of methods to reduce nitrate in drainage water, it was estimated that the 

41 potential for nitrate load reduction with controlled drainage is approximately 50 percent 

42 (Appelboom and Fouss 2006). Skaggs and Youssef (2008) reported a wide range of discharge 
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1 reduction (17–-85 percent) and nitrate load reduction (18–-85 percent) in a summary of studies 

2 conducted in North CarolinaNC, Ohio, Sweden, and Canada. The authors note that controlled 

3 drainage increases evapotranspiration (ET), surface runoff, and deep and lateral seepage, with 

4 ET accounting for only 8–-15 percent of the reduction in subsurface drainage compared to 

5 conventional drainage and seepage effects dependent on the size and boundary conditions of the 

6 fields under controlled drainage. The effects of size and boundary condition on discharge are 

7 illustrated by the different findings for field and plot studies in Canada (Tan, Drury et al. 2004). 

8 Reductions in nitrate concentration from due to controlled drainage were minimal in most 

9 studies, so it is important to know what happens to the nitrate in the seepage water. Evidence 

10 indicates that in poorly or very poorly drained soils, the nitrate is reduced at depths greater than 1 

11 mmeter or so, providing effective reduction of N losses to the environment. 

12 Ditch Management Practice Effectiveness 

13 In a 2-year study of two experimental farm drainage ditches serving land planted in a summer 

14 row crop/winter fallow sequence in northern Mississippi, monthly baseflow and stormflow (28 

15 storms) regression results indicated that drainage ditches reduced nitrate and ammonia over the 

16 length of the ditch for both growing and dormant seasons (Kroger, Holland et al. 2007). 

17 Maximum farm effluent dissolved inorganic N load, defined as the highest load attained spatially 

18 within the drainage ditch as a result of the combination of surface and subsurface flow processes, 

19 was reduced by an average of 57 percent by the ditches. 

20 Sediment from two similar drainage ditches in the Atlantic coastal plain were sampled (0–-5 cm) 

21 after one of the ditches had been dredged, removing fine-textured sediments (clay = 41 percent) 

22 with high organic matter content (85 g/kg) and exposing coarse-textured sediments (clay = 15 

23 percent) with low organic matter content (2.2 g/kg) (Shigaki, Kleinman et al. 2008). Laboratory 

24 testing in a flume revealed that under conditions of low initial P concentrations, sediment from 

25 the dredged ditch released 13 times less P to the water than did sediment from the ditch that had 

26 not been dredged, but the sediments from the dredged ditch removed 19 percent less P from the 

27 flume water when it was spiked with dissolved P to approximate long-term runoff 

28 concentrations. Irradiation of sediments to destroy microorganisms revealed that biological 

29 processes accounted for up to 30 percent of P uptake in the coarse-textured sediment of the 

30 dredged ditch and 18 percent in the fine-textured sediment of the undredged ditch. 

31 Because vegetation in ditches increases sediment retention, cycles nutrients, and promotes the 

32 development of soil structure, it is proposed that management procedures that encourage ditch 

33 vegetation, such as targeted clean-outs and gradual inundation, may increase the stability and 

34 ecosystem services of ditch soils (Needelman, Ruppert et al. 2006). A study in Florida to 

35 evaluate P characteristics of agricultural ditch soils in the Lake Okeechobee Basin found that in36 ditch management practices, such as usingthe use of soil amendments or controlled drainage, 

37 could be useful to reduce P loss from ditch soils (Dunne, McKee et al. 2006). 

38 Bioreactors Effectiveness 

39 Several studies have measured the effectiveness of bioreactors in removing nitrate and other 

40 contaminants from agricultural drainage water (Table 2-2927). 
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1 Table 2-2927. Measured nitrate removal rates for bioreactors 

Removal (%) 

Location Practice 

Flowthrough rate 

(L/min) 

NO3-N 

conc. 

NO3-N 

load Source 

IA Wood-chip denitrification walls 65%a161%-68%a1Jaynes, Kaspar

et al. 2004 

MN Wood chip bioreactor 38% 

Wood chip bioreactor plus CD 88% 

Thorstensen No 

date 

Denitrification reactor using wood 

particles—Lateral Flow Design 

Ontario, 7.7 32% 

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)b2

60%–-90% Appelboom and 

Fouss 2006 

Various Constructed bioreactors (review 

article)b2

60%–-

100% 

Kalita, Cooke et 

al. 2007 

Notes:

a. FOOTNOTES:

1Reduction compared to uncontrolled drainage. 

b.2 Reviews include some of the other studies shown. 

2 

3 In an Iowa study comparing several tile and cropping modifications for reducing nitrate in tile 

4 drainage versus the nitrate concentration in drainage from a UD treatment (tile at 1.2 m), it was 

5 found that denitrification walls (DW) reduced the nitrate concentration in tile drainage by an 

6 average of 65 percent and the tile drainage N load by 61–-68 percent compared to UD (Jaynes, 

7 Kaspar et al. 2004).

8 A bioreactor (24.4-m meters long x 0.76-m meters wide x 1.5-m meters deep) in Minnesota that 

9 is paired with a CD system has reduced TSStotal suspended solids by 74 percent, TP by 78 

10 percent, nitrate by 38 percent, and E. coliColi by 52 percent in drainage water from 3.2 hectares 

11 of farmland (Thorstensen No date). Combined, the bioreactor and CD reduced nitrate and TP in 

12 the drainage water by 88 percent. 

13 Two denitrification reactor designs using fine and coarse wood particles, a lateral flow design 

14 and an upflow design, were tested under baseflow conditions in southern Ontario, the former 

15 over a 26-month period on drainage from a cornfield, and the latter over a 20-month period on 

16 drainage from a golf course (van Driel, Robertson et al. 2006). Removal by the reactor at the 

17 cornfield site averaged 3.9 mg N/L at an average flow-through rate of 7.7 L/min and an average 

18 influent nitrate concentration of 11.8 mg N/L. With an average flow-through and influent nitrate 
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1 concentration of 7.8 L/min and 3.2 mg N/L, respectively, removal by the reactor at the golf 

2 course site averaged 1.7 mg N/L. Mass balance calculations indicate that carbon consumption 

3 from denitrification was < 2 percent per year, showing the potential for the reactors to operate for 

4 a number of years without the need for media replenishment. 

A 40-m35 woodchip bioreactor was trenched into the bottom of an existing agricultural drainage 

6 ditch in Ontario, Canada, with flow induced through the reactor by construction of a gravel riffle 

7 in the streambed (Robertson and Merkley 2009). Over the first 1.5 years of operation, a mean 

8 influent nitrate concentration of 4.8 mg/L was reduced to 1.04 mg/L at a mean reactor flow rate 

9 of 24 L/min. A series of flow-step tests, facilitated by an adjustable height outlet pipe, 

10 demonstrated that nitrate mass removal generally increased with increasing flow rate. Silt 

11 accumulation reduced reactor flow rates over time, but design modifications were implemented 

12 to address the problem. 

13 In a 1-year pilot-scale study, two 200-L fixed-bed bioreactors containing coarse sand and organic 

14 carbon (tree bark, wood chips, and leaf compost) were used to treat NO3 contamination from 

15 agricultural runoff (Blowes, Robertson et al. 1994). At inflow rates of 10–-60 L/day, NO3-N 

16 concentrations of 3–6 mg/L in farm-field drainage tiles were reduced by the reactors to less than 

17 0.02 mg/L. 

In Ontario, a pilot-scale assessment of a plywood-framed (1.9 m318 ) subsurface reactor filled with 

19 coarse wood mulch documented a 58 percent removal of nitrate from farm drainage water 

20 influent at hydraulic loading rates ranging from 800 to 2,000 L/day (Robertson, Blowes et al. 

21 2000). Nitrate consumption rates were temperature dependent, ranging from 5 mg/L N per day at 

22 2–-5 °C, to 15–-30 mg/L N per day at 10–-20 °C, but did not deteriorate over the 7-year 

23 monitoring period. Mass-balance calculations of carbon consumption indicated that the reactor 

24 could perform well for at least a decade without carbon replenishment. 

25 In a review of methods to reduce nitrate in drainage water, it was estimated that the potential for 

26 nitrate reduction is 60 to 90 percent for constructed bioreactors (Appelboom and Fouss 2006). 

27 A review of bioreactors in the Midwest found that they could reduce nitrate levels by 60–-100 

28 percent (Kalita, Cooke et al. 2007). In addition, the authors identified the following advantages 

29 of bioreactors: 

30 • They use proven technology,

31 • They require no modification of current practices 

32 • No land needs to be taken out of production 

33 • There is no decrease in drainage effectiveness over time 

34 • They require little or no maintenance, and

35 • They can last for up to 20 years.

36 Constructed Wetlands Effectiveness 

37 In a review of methods to reduce nitrate in drainage water, it was estimated that the potential for 

38 nitrate reduction is 37– to 65 percent for natural/constructed wetlands, with up to an additional 

39 18 percent if a berm is used in creation of the wetland (Appelboom and Fouss 2006). A 
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1 combination of controlled-drainage, constructed wetland, and in-stream denitrification could 

2 possibly result in more than 75 percent nitrate removal before prior to release to larger streams or 

3 other surface waters. 

4 Measurement over 3 three years of Nnitrogen removal rates in three large (0.3 to 0.8 ha, 1200 to 

5,400 m35 in volume) constructed wetlands treating tile drainage from corn and soybean fields in 

6 southern Illinois indicated TNtotal nitrogen removal of 37 percent in the wetlands (Kovacic, 

7 David et al. 2000). The wetlands also decreased NO3-N concentrations of inlet water by 28 

8 percent, and coupling the wetlands with a 15.3-m buffer strip between the wetlands and the river 

9 removed an additional 9 percent of the tile NO3-N, increasing the N removal efficiency to 46 

10 percent. TTotal P removal was only 2 percent during the 3-yearyr period, with highly variable 

11 results in each wetland and year. 

Two agricultural runoff wetlands, W1 (area 0.16 ha, volume 660 m312 ) and W2 (area 0.4 ha, 

volume 1780 m313 ), intercepting surface and tile drainage in the Lake Bloomington, Illinois, 

14 watershed, achieved a mass NO3-N retention of 36 percent (Kovacic, Twait et al. 2005). 

15 Wetlands W1 and W2 reduced overall volume-weighted nitrate concentrations by 42 percent and 

16 31 percent, respectively. Combined P mass retention was 53 percent, and combined total organic 

17 carbon (TOC) mass retention was 9 percent. 

18 The integration of constructed wetlands within agricultural Wetland Reservoir Subirrigation 

19 Systems (WRSIS) is being evaluated at three demonstration sites in Ohio (Allred, et al. 2008). 

20 Each WRSIS is composedcomprised of a constructed wetland, a water storage reservoir, and a 

21 network of subsurface pipes used at different times to either drain or irrigate crops through the 

22 root zone. WRSIS can be operated hydraulically in a closed- loop mode most of the time with 

23 off-site water release restricted, creating opportunities to route agricultural field runoff and 

24 subsurface drainage to the wetland for water treatment, and then to the storage reservoir where it 

25 is held until needed to subirrigate field crops during dry timesparts of the growing season. Water 

26 quality measurements have been tabulated for 2003 through 2007, and two of the three WRSIS 

27 wetlands have shown substantial effectiveness in removing suspended sediment, nitrate, and 

28 TNtotal nitrogen. 

29 Practice Costs 

30 Dual-purpose drainage/subirrigation systems provide for drainage, controlled drainage, and 

31 subirrigation (Evans and Skaggs 1996). Systems designed primarily for drainage mightmay need 

32 to be redesigned or managed more intensively to serve as dual-purpose systems. The three major 

33 expenses of installing and operating a drainage and subirrigation system are the cost of a water 

34 supply, underground tubing installation, and land grading (Evans, Skaggs et al. 1996). If 

35 subirrigation is not part of the system, a water supply is not needed, but increased yields realized 

36 with subirrigation can contribute to nitrate reductions because of due to increased crop uptake. 

37 On the basis of Based on estimates for 1996, water supply ponds sufficient to irrigate 

38 approximately 40 ha would cost about $68,000–$-$81,500 in 2008 dollars, but other water 

39 supplies (e.g., stream) could be much cheaper. Underground tubing installation costs are 

40 generally the largest single expense, varying with the total footage, tubing diameter, installation 

41 method, and whether filter material is used. The amount of tubing needed depends on the 

42 hydraulic conductivity of the soil, with spacing ranging from 40 to 100 feet in North 

43 Carolina.NC. The cost of 10-cm tubing ranges from about 76 cents to just over $1one dollar per 
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1 meter, with filter material adding another 31 to 53 cents per meter. The cost to install 

2 underground tubing depends on the specific job, but can range from about $1.34/mmeter to 

3 $2.23/mmeter for 10-cm tubing. UsingBased on the estimates for 1996, total cost to install tubing 

4 at 10-mmeter spacing is about $2,660/ha, whereas the cost for 30-mmeter spacing is about 

5 $880/ha. Land grading could add $170 to $850/ha to the cost, and the cost of control structures 

6 ranges from about $400 to more than $4,000. Finally, installation generally requires field borders 

7 to stabilize open ditches at a cost of about $100 per production hectare. 

8 A cost analysis for controlled drainage in the lower coastal plain of North Carolina assumed the 

9 need for a surface drainage system of 0.9- to 1.5-meter-deep open ditches, a flashboard riser 

10 installed in the collector canal, a corrugated metal pipe culvert for an outlet, and concrete to 

11 stabilize the riser (Wossink and Osmond 2001). It was assumed that there would be no 

12 installation and maintenance costs for ditches because they were part of the pre-existing 

13 condition. On the basis of Based on a land slope of 0.1 to 0.4 m/kmeters per kilometer, it was 

14 assumed that there would be one structure per mile in the canal on a 0.6- to 0.75-mmeter contour 

15 interval, meaning that one control structure in the main canal would serve 130 hectares. It was 

16 also assumed that under controlled drainage soybeans and cotton yields would increase by 2 

17 percent or more, corn yields would increase by 5 percent or more, and wheat and tobacco yields 

18 would not increase. Installation costs for controlled drainage were estimated to be $57.20/ha 

19 (2008 dollars), while annual maintenance was estimated at $3.75/ha, and benefits from yield 

20 increases were estimated at $6.03/ha to $33.12/ha. Assuming cost-share availability of about 

21 $45/ha, the authors concluded that cost-shared controlled drainage was financially practical for 

22 the lower coastal plain of NC. 

23 In a demonstration plot in Minnesota, the costs associated with controlled drainage included 

24 drainage control structures, design, installation, extra pipe and installation, totaling about $35/ha 

25 for a 65-ha field (Binstock 2009). Tile spacing was set at 22.8 meters, using 10-cm diameter 

26 laterals on a slope of just under 1 percent. It has been estimated that drainage management 

27 systems cost about $50 to $500/ha more than conventional drainage systems (Newby 2009). 

28 Water control structures for drainage water management cost from about $530 to $2,100 (2008 

29 dollars) depending on height, size of tile, structure design, manufacturer, and whether it is 

30 automated (Frankenberger, et al. 2006). Installation costs for structures are about $215 for basic 

31 structures, increasing with size and complexity. Assuming flat terrain, a single structure could 

32 serve 8 hectares at a cost of $70 to $265 per hahectare. 

33 Both a lateral flow design and an upflow design bioreactor tested in Ontario were successful in 

34 achieving maintenance-free operation during all seasonal conditions, including unassisted startup 

35 after drought and freeze periods (van Driel, Robertson et al. 2006). Construction cost per unit 

36 Nnitrogen removal for bioreactors designed to manage baseflow conditions are expected to be 

37 similar to the cost for constructed wetlands, but less land is required for the bioreactors. 

38 A woodchip bioreactor (38 mmeters long by 1.8 mmeters deep by 0.6–0-.9 mmeters wide) in 

39 Minnesota cost approximately $3,200 to construct (Minnesota DepartmentDept. of Agriculture 

40 No dateUndated). Control structures cost $1,500, trenching cost $1,100, and $600 was spent on 

41 woodchips. Serving approximately 3.2 ha, the bioreactor cost is about $990/ha and is expected to 

42 work for about 20 years. The cost of a 60-mmeter bioreactor ranges from about $2,900 to $4,300 

43 depending on materials and design (Morrison 2008). 
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1 4.4 Animal Feeding Operations 

2 Animal feeding operationsFeeding Operations (AFOs) congregate animals, feed, wastes, and 

3 production operations on a small land area. Water pollution by animal production can be caused 

4 by leaching and runoff of organic matter, N, P, and pathogens from animal congregation areas or 

5 other parts of the facility before wastes are otherwise contained or managed (see Section 2). Key 

6 strategies for edge of field trapping and treatment of AFO runoff include vegetated filter strips

7 (VFS) and other techniques to capture runoff from feedlots, barnyards, and other facility areas 

8 and remove sediment, nutrients, and other pollutants before delivery to surface waters. 

9 Water quality effectsimpacts from AFOs using grazing and pasture land include nutrients and 

10 pathogens in runoff from areas of waste deposition and soil loss from areas of degraded 

11 vegetation cover. While livestock exclusion (see Section 2) and pasture management (see 

12 Section 3.4X) are often the main approaches to managing water quality effectsimpacts from 

13 grazing livestock, non-grazed, vegetated buffer strips or other edge-of-field practices are often 

14 recommended to protect waterbodies from sediments and nutrients in runoff from grazed 

15 pastures. 

Implementation Measure: Manage all livestock production runoff and runoff from grazing and 

pasture areas to minimize off-farm transport of nutrients and sediment.

16 Implementation measure: Manage all livestock production runoff, as well as runoff from 

17 grazing and pasture areas to minimize off-farm transport of nutrients and sediment.

18 Practice Effectiveness 

19 Production Area Effectiveness 

20 Based on a review of the literature, Koelsch et al. (2006) presented the following conclusions 

21 about the application of vegetative treatment systems (VTS) to manage runoff from open lot 

22 livestock production areas: 

23 • The pollutant reduction resulting from a VTS is based upon two primary mechanisms: (1) 

24 sedimentation, typically occurring within the first few meters of a VTS, and (2) 

25 infiltration of runoff into the soil profile. System design based upon sedimentation and 

26 infiltration is necessary to achieve a required performance level for concentrated AFO

27 (CAFO) application. 

28 • Critical design factors specific to attaining high levels of pollutant reduction within a 

29 VTS include pre-treatment, sheet flow, discharge control, siting, and sizing. Critical 

30 management factors include maintaining maintenance of a dense vegetation stand and 

31 sheet flow of runoff across VTA as well as minimizing minimization of nutrient 

32 accumulation. 

33 The authors report numerous pollutant removal rates for a variety of VTS under a broad range of 

34 circumstances. In general, the literature reports 70–-90 percent TS removal, 80 percent N 

35 removal, 70 percent P removal, and 77 percent fecal coliform removal from CAFO runoff treated 

36 by VTS. 
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1 In Nebraska, Woodbury et al. (2000, and 2002) tested a flat-bottom terrace to collect runoff 

2 from a beef feedlot to provide temporary liquid storage, and accumulate settable solids, while 

3 distributing the liquid fraction uniformly across a VFSvegetative filter strip. No runoff left the 

4 VFSvegetative filter strip, indicating that the basin discharge was usedutilized for grass 

5 production. In a follow-up study, Woodbury et al. (2003) reported that the system reduced the 

6 cumulative mass of TSS (80 percent), VSS (67 percent), and COD (59 percent) 

7 Kim et al. (2003) studied flow and P transport through a VFSvegetated filter strips receiving 

8 milkhouse wastewater and barnyard runoff from two New York dairy farms. Although 33 m–40

9 m VFS eventually reduced soluble P to < 0.2 mg/L, P was less effectively removed where soil 

10 saturation occurred. Wastewater entering a VFS should be distributed uniformly to avoid soil 

11 saturation. 

12 In Montana, Fajardo et al. (2001) reported on the effectiveness of VFS using tall fescue in 

13 treating runoff from livestock manure stockpiles. Runoff NO3-N concentrations were reduced by 

14 97–99 percent by a VFS. Coliform bacteria counts were reduced by 64–87 percent, although 

15 bacteria counts in runoff leaving the VFS remained elevated, even for treatments not receiving 

16 manure. 

17 VFSVegetative filter strips were effective in removing a broad range of constituents from a 

18 Kansas beef feedlot runoff pretreated by a settling basin (Mankin and Okoren 2003). The first 30 

19 m provided most or all of the reductions found within the 150-m VFSVFSs studied: reductions 

20 averaged 85 percent of inflow water, 85 percent of sediment, 77 percent of N, and 84 percent of 

21 P. Fecal bacteria removal by the VFSVFSs was on the order of 1-log: reductions at 30 m ranged 

22 from 84 percent for FC and FS to 91 percent for E. coli. 

23 In Illinois, Trask et al. (2004) reported that a VFS can be a BMP for controlling Cryptosporidium

24 in runoff from animal production facilities. The vegetative surface was very effective in reducing 

25 C. parvum in surface runoff; for all slopes and rainfall intensities, recovery of C. parvum oocysts 

26 was considerably less from a vegetated surface than from the bare-ground conditions. For a 25.4 

27 mm/h rainfall event, recovery of oocysts in overland flow from the VFS varied from 0.6 to 1.7 

28 percent, while those from the bare ground condition varied from 4.4 to 14.5 percent. For the 63.5 

29 mm/h rainfall, the recovery percentages of oocysts varied from 0.8 to 27.2 percent from the VFS, 

30 and 5.3 to 59 percent from bare-ground conditions. 

31 Hubbard et al. (2007) tested the performance of grass-forest vegetated buffers in assimilating N 

32 from overland flow application of swine lagoon effluent in Georgia. The buffers approximated 

33 60 m in length by 90 m in width. The upper 10 m of each buffer was in grass, while the 

34 downslope area was in mature or newly planted pines. Shallow groundwater under the buffers 

35 showed nitrate (NO3-N) concentrations 20–30 m downslope to be <10 mg/L. On thosethese

36 buffers, NO3-N concentrations in shallow groundwater were near background levels 5five years 

37 after wastewater application commenced. The ratio of buffer area width to wastewater 

38 application area width on the landscape should be at least 1:1. 

39 In Kansas, Mankin et al. (2006) quantified beef cattle feedlot runoff quality, particularly during 

40 unstocked conditions, and evaluated reductions of fecal bacteria and nutrients in VFSvegetative 

41 filter strips treating feedlot runoff. Events when few or no cattle were present averaged 17 

42 percent of Tthe total N (20 mg/L), 14 percent of Tthe total P (6 mg/L), and 2 percent of the fecal 
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coliforms (2.1 x 1041 cfu 100/mL) of events with cattle present. Measured concentration 

2 reductions from all events and VFSvegetative filter strips averaged 77 percent (fecal coliforms), 

3 83 percent (E. coli), 83 percent (fecal streptococci), 66 percent (Ttotal N), and 66 percent (TP). 

4 VFStotal P). Vegetative filter strips allowed no discharges for > 90 percent of feedlot runoff 

5 events at the sites with the ratio of VFSvegetative filter strip: drainage area > 0.5. 

6 Gilley et al. (2008) compared nutrient transport in runoff from beef feedlots in Nebraska with 

7 loose manure surfaces versusvs. compacted surfaces. No significant differences in feedlot soil 

8 characteristics or nutrient transport in runoff were found between loose and compacted surfaces. 

9 However, concentrations of E. coli were significantly greater in runoff from the loose surface 

10 feedlots. 

11 In Finland, Narvanen et al. (2008) tested a ferric sulfate dosing system to treat runoff from horse 

12 paddocks; runoff was then discharged into a sedimentation pond and sand filter. Dissolved P was 

13 reduced by 95 percent, Ttotal P by 81 percent. 

14 Robertson and Merkley (2009) demonstrated an in-stream bioreactor using woodchips to 

15 promote denitrification of agricultural drainage in Ontario, Canada. Over the first 1.5 years of 

16 operation, mean influent NO3-N of 4.8 mg/L was attenuated to 1.04 mg/L (a 78 percent 

17 reduction) at a mean reactor flow rate of 24 L/min. When removal rates were not nitrate-limited, 

areal mass removal ranged from 11 mg N/m2/h at 3 oC to 220 mg N/m218 hr at 14°C, exceeding 

19 rates reported for some surface-flow constructed wetlands by a factor of about 40. 

20 Table 2-3028. Summary of reported practice effects resulting from VFS treatment of AFO runoff.

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 VFSvegetative 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 

NO3-N concentrations by 97%–-99% and coliform 

bacteria counts by 64%–-87%a1

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 2003 
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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 the 

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 

bufferbbuffer2

Shallow groundwater under the buffers showed 

nitrate (NO3-N) concentrations 20–30 m downslope 

to be <10 mg/L. On these buffers, NO3-N 

concentrations in shallow groundwater were near 

background levels 5five 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 Ttotal N, 14% of the Ttotal 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% (Ttotal N), and 66% (Ttotal 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%, Ttotal P by 81% 

using a ferric sulfate dosing system and sand filter to 

treat runoff from horse paddocks 

Narvanen et 

al. 2008 

Ontario, 

Canada 

BMP Woodchip 

bioreactor 

Treating AFO drainage, NO3-N was attenuated to 

1.04 mg/L (78% reduction); areal mass removal 

ranged from 11 mg N/m2

/h at 3 °

oC to 220 mg N/m2

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 

2 Buffer/filter strips treating pasture runoff 

3 Sotomayor-Ramirez et al. (2008) tested 10- and 20- m grassed filter strips treating runoff from 

4 grazed pasture amended with dairy manure sludge in Puerto Rico. Filter strips reduced TP and 

5 dissolved P concentrations by 29 percent and 32 percent at 10 m, and by 57 percent and 49 

6 percent at 20 m, respectively. A 27 percent decrease in TKN concentration was observed in one 

7 field as a result of the 20-m filter strip. 

8 Tate et al. (2000) evaluated the potential water quality improvements from 10- m buffer strips on 

9 irrigated land in California. The 10- m buffer did not significantly reduce concentrations and 

10 load of NO3-N in runoff from sprinkler and flood irrigated pastures. The buffer also failed to 
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Chapter 2. Agriculture 2-125 

1 reduce TTotal P concentration under either irrigation schemes, or TTotal P and TSS load under 

2 sprinkler irrigation. 

3 The presence of a vegetated buffer of any size (from 1 to –25 m), generally reduced median fecal 

4 coliform bacteria concentrations and loads in runoff from Oregon pasture land by more than 99 

5 percent (Sullivan et al. 2007). 

6 Other practices treating pasture runoff 

7 Tanner et al. (2005) reported on the performance of a surface-flow constructed wetland 

8 (occupying ~1 percent of the catchment area) treating subsurface drainage from rain-fed, dairy 

cattle grazed pasture in New Zealand. TN mass removal efficiency was 79 percent (841 g/m29 per 

year) the first year, but declined to 21 percent (40 g/m210 per year) in the second year, associated 

11 with changes in the magnitude, speciation and seasonal pattern of N export from the catchment. 

12 TP export rose by 101 percent (5.0 g/m per year) after passage through the wetland in the first 

year, but decreased by 12 percent (0.2 g/m213 per year) in the second year. The results show that 

14 constructed wetlands composingcomprising similar to 1 percent of catchment area can markedly 

15 reduce N export via pastoral drainage, but couldmay be net sources of NH4-N, DRP and TP 

16 during establishment. 

17 Knox et al. (2008) examined benefits to water quality provided by a natural, flow-through 

18 wetland receiving runoff from irrigated pasture in California. The wetland reduced loads of TSS 

19 (77 percent), nitrate (60 percent), and E. coli (68 percent). Retention of TN, Ttotal N, total P, and 

20 SRsoluble reactive P was between 35 and 42 percent of loads entering the wetland. 

21 Table 2-3129. Summary of reported practice effects resulting from buffer/wetland treatment of 

22 pasture runoff.

Location 

Study 

type Practice Practice effects Source 

Puerto 

Rico 

BMP Grassed 

filter strips 

Filter strips treating runoff from grazed pasture reduced 

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 concentrations 

and load of NO3-N in runoff from sprinkler and flood 

irrigated pastures. The buffer also failed to reduce 

TTotal P concentration under either irrigation schemes, 

or TTotal 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 (from 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 was 

79% (841 g/m2 per year) the first year, but declined to 

21% (40 g/m2 per year) in the second year. TP export 

rose by 101% (5.0 g/m per year) after passage through 

the wetland in the first year, but decreased by 12% (0.2 

g/m2 per year) in the second year. 

Tanner et al. 

2005 
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Chapter 2. Agriculture 2-126 

CA BMP Natural 

wetland 

Wetland receiving runoff from irrigated pasture reduced 

loads of TSS (77%), nitrate (60%), and E. coli (68%). 

35% to 42% of TN, Ttotal N, total P, and SRsoluble 

reactive P loads entering the wetland were retained. 

Knox et al. 

2008 

1 
3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote — 

Chapter 2. Agriculture 2-127 

1 Appendices 

2 Appendix 1: USDA Conservation Practice Standards (Practice Codes)

3 Referenced throughout the document

4 Appendix 2: AgriculturalExisting Tools in Support of Section 502 Technical Guidance

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6 Quality 35:, 207–-215. 

7 

8 

9 

10 

11 

12 (POTENTIAL AND LIMITATIONS OF COVER CROPS, LIVING MULCHES, AND

13 PERENNIALS TO REDUCE NUTRIENT LOSSES TO WATER SOURCES FROM

14 AGRICULTURAL FIELDS

15 T.C. Kaspar, Plant Physiologist, USDA-ARS, National Soil Tilth Laboratory;

16 E.J. Kladivko, Professor of Soil Physics, Agronomy Dept., Purdue University;

17 J.W. Singer, Research Agronomist, USDA-ARS, National Soil Tilth Laboratory

18 S. Morse, Senior Fellow, Agronomy/Plant Genetics, University of Minnesota

19 D. Mutch, Cover Crops/Field Crops IPM Specialist, KBS, Michigan State University

20 http://www.epa.gov/msbasin/pdf/10covercrops.pdf Gulf Hypoxia and Local Water Quality 

21 Concerns Workshop, September 26-28, 2005, Ames, IA)

22 [CONTROLLED DRAINAGE MANAGEMENT GUIDELINES FOR IMPROVING 

23 DRAINAGE WATER QUALITY Prepared by:

24 Robert Evans, Extension Agricultural Engineering Specialist

25 J.W. Gilliam, Professor of Soil Science

26 Wayne Skaggs, William Neal Reynolds Professor

27 Department of Biological and Agricultural Engineering

28 Published by: North Carolina Cooperative Extension Service

29 Publication Number: AG 443

30 Last Electronic Revision: June 1996 (KNS)]

31 Hartwig, N.L., and H.U. Ammon. 2002. Cover crops and living mulches. Weed Sci. 50:688-699.

32 (POTENTIAL AND LIMITATIONS OF COVER CROPS, LIVING MULCHES, AND 

33 PERENNIALS TO REDUCE NUTRIENT LOSSES TO WATER SOURCES FROM 

34 AGRICULTURAL FIELDS

35 T.C. Kaspar, Plant Physiologist, USDA-ARS, National Soil Tilth Laboratory;
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Chapter 2. Agriculture 2-155 

1 E.J. Kladivko, Professor of Soil Physics, Agronomy Dept., Purdue University;

2 J.W. Singer, Research Agronomist, USDA-ARS, National Soil Tilth Laboratory

3 S. Morse, Senior Fellow, Agronomy/Plant Genetics, University of Minnesota

4 D. Mutch, Cover Crops/Field Crops IPM Specialist, KBS, Michigan State University

5 http://www.epa.gov/msbasin/pdf/10covercrops.pdf Gulf Hypoxia and Local Water Quality 

6 Concerns Workshop, September 26-28, 2005, Ames, IA)

7 [CONTROLLED DRAINAGE MANAGEMENT GUIDELINES FOR IMPROVING 

8 DRAINAGE WATER QUALITY Prepared by: 

9 Robert Evans, Extension Agricultural Engineering Specialist 

10 J.W. Gilliam, Professor of Soil Science 

11 Wayne Skaggs, William Neal Reynolds Professor 

12 Department of Biological and Agricultural Engineering

13 Published by: North Carolina Cooperative Extension Service

14 Publication Number: AG 443

15 Last Electronic Revision: June 1996 (KNS)]

16 Blackmer, A.M. and A.P. Mallarino. 1996. Cornstalk Testing to Evaluate Nitrogen Management 

17 (PM-1584). Iowa State Univ. Extension. This page provides links to nutrient management 

18 training courses including the P index, information on nutrient management consultant 

19 certification, manure sampling and analysis methods, and related websites.
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Chapter 2. Agriculture 2-156 

1 Appendix 1: USDA Conservation Practice Standards 

2 (Practice Codes)Referenced throughout the document

3 
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Chapter 2. Agriculture 2-164 
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Chapter 2. Agriculture 2-165 

1 Appendix 2: Agricultural Tools in Support of Section 502 

2 Technical Guidance 

3 Included in this appendix are summaries of online tools that can be used by producers, planners, 

4 and managers to develop plans for these practices. 

5 The tools and resources summarized in this table and described below are not intended to 

6 provide push-button farm management plans that will solve all of the environmental problems 

7 addressed by the Section 502 Technical Guidance. Rather, these tools are generally used by 

8 experts (e.g., USDA field technicians and engineers) to work with clients to design appropriate 

9 conservation plans for their lands. When developing management plans for their operations, 

10 producers generally rely on a range of information and expertise derived from USDA, 

11 universities, soil and water conservation districts, other producers, and the private sector. A 

12 range of tools and resources are summarized in the Table below and represent those that are 

13 generally used by experts (e.g., USDA field technicians and engineers) to work with clients to 

14 design appropriate conservation plans for their lands. Most of the tools listed below are available 

15 for free. 

16 

# Tool nameName and document 

linkDocument Link

Applicable 

practicesaPractices1

Source and Web linkLink

 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.
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Chapter 2. Agriculture 2-166 

# Tool nameName and document 

linkDocument Link

Applicable 

practicesaPractices1

Source and Web linkLink

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 Water 
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Chapter 2. Agriculture 2-167 

# Tool nameName and document 

linkDocument Link

Applicable 

practicesaPractices1

Source and Web linkLink

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. 1AWM=animal waste management, DWM=drainage water management, ESC=erosion and sediment control, 

GM=grazing management, NM=nutrient management 
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Chapter 2. Agriculture 2-168 

1 I. Software and Models 

2 1. Nutrient Management Planning Software for Professionals (NuMan Pro)—Univ. 

3 Maryland Extension 

4 Nutrient Management for Maryland Professional Edition (NuMan Pro) is an integrated software 

5 program that permits comprehensive nutrient management planning. The Maryland Phosphorus 

6 Site Index (PSI) has been integrated into the program so that warnings are given when a 

7 PSIphosphorus site index calculation may be required based on soil test results. A simplified 

8 version of the Revised Universal Soil Loss Equation (RUSLE) model to predict soil erosion 

9 losses has been included in the program in support of the Maryland PSI assessment. Values for 

10 rainfall erosivity (R) and soil erodibility (K) factors are determined from field location and soils 

11 information entered in the initial portions of the program. Soil slope/steepness (LS), cropping 

12 management (C), and conservation management (P) factors are determined from simplified user 

13 inputs. Part A and Part B of the Maryland PSI are presented in a color-code scheme for user ease. 

14 Once slopes have been identified in the field, it is estimated that an experienced user can 

15 determine the Maryland PSI in less than 10 minutes.

16 Link: http://anmp.umd.edu/numan/numanpro.htm AccessedRetrieved January 28, 2010 

17 2. AFOPro—Earth Sciences and Research Institute, University of South Carolina 

AFOProTM 18 is a standalone nutrient management planning tool with optional connections to GIS 

19 (ArcMap© and ArcView©) and the NRCS’s Animal Waste Management (v 2.0.2 or higher) 

20 engineering software. The application allows the user to plan manure and commercial fertilizer 

21 allocation decisions in compliance with the NRCS’s 590 Standard, which requires the 

22 documentation of form, source, timing, method, and placement of nutrients. The design of the 

23 application is open, transparent, and flexible which enables it to be adapted to specific state crop 

24 removals, nutrient risk ratings, and Nnitrogen accounting requirements. Additionally, the 

25 application uses modular Phosphorus Indices, state-specific fertility recommendations and state26 specific CNMP templates. 

27 Link: http://www.esri.sc.edu/Projects/usda/application_development/afopro.asp

28 AccessedRetrieved January 28, 2010 

29 3. Animal Waste Management Software—USDA-NRCS 

30 AWM 2.4.0, like the previous version, is a planning/design tool for animal feeding operations 

31 that can be used to estimate the production of manure, bedding, and process water and determine 

32 the size of storage/treatment facilities. The procedures and calculations used in AWM are based 

33 on the USDA-NRCS Agricultural Waste Management Field Handbook. 

34 The AWM has been upgraded with the capability to evaluate existing facilities. The results from 

35 the evaluation are incorporated into the design processes for new facilities. The user can design 

36 the new facility either for the Additional waste not handled by the existing facility, or for the 

37 Total waste flowing into the structure. 

38 The evaluation process involves the user entering the basic dimensions of an existing storage 

39 facility along with other parameters such as herd size, local climatic condition (monthly rainfall), 

40 and details about the additions such as bedding, wash water and flush water. With these inputs 
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Chapter 2. Agriculture 2-169 

1 the system estimates the total waste flowing into the structure identified in the management train 

2 for the selected storage period and compares it the available storage volume. It then presents an 

3 on-screen color coded report (red for inadequate and the green for the adequate structure.) This 

4 report helps recognize if the structure is adequately designed or not easily and quickly. The user 

5 can also print a hardcopy of this report. 

6 The AWM process of evaluating existing structures can help producers in deciding if they would 

7 like to go for the No Discharge declaration within the EPA 2008 CAFO rule. The facility design 

8 for the Total waste or for the Additional waste not handled by the existing structure is easily 

9 done by selecting the appropriate radio button on the AWM design screen. In addition, several 

10 improvements and bug fixes, listed below, have been incorporated to further improve AWM 

11 functions and capabilities. 

12 Link: http://www.wsi.nrcs.usda.gov/products/W2Q/AWM/pgrm24.html AccessedRetrieved

13 January 22, 2010 

14 4. Manure Management Planner (MMP) Software— - Purdue University 

15 Manure Management Planner (MMP) is a Windows-based computer program developed at 

16 Purdue University that is used to create manure management plans for crop and animal feeding 

17 operations. The user enters information about the operation’soperation's fields, crops, storage, 

18 animals, and application equipment. MMP helps the user allocate manure (where, when and how 

19 much) on a monthly basis for the length of the plan (1-10 years). This allocation process helps 

20 determine if the current operation has sufficient crop acreage, seasonal land availability, manure 

21 storage capacity, and application equipment to manage the manure produced in an 

22 environmentally responsible manner. MMP is also useful for identifying changes that may be 

23 needed for a non-sustainable operation to become sustainable, and determine what changes may 

24 be needed to keep an operation sustainable if the operation expands. 

25 MMP currently supports 34 states including DE, MD, and PA (support for VA is underway), by 

26 automatically generating fertilizer recommendations and estimating manure N availability based 

27 on each state’sstate's Extension and/or NRCS guidelines. It should be noted, however, that MMP 

28 is not generally used in Maryland. Questions about MMP can be addressed to the authors using 

29 contact information provided at the website. 

30 Link: http://www.agry.purdue.edu/mmp/ AccessedRetrieved January 22, 2010 

31 5. National Nutrient Management Data Download—Univ. of Missouri Extension 

32 The data download website helps to address nutrient management software data requirements by 

33 providing a way for users to locate the farm of interest, define an area of interest and submit a 

34 data request. 

35 • The Spatial Nutrient Management Planner (SNMP) requires geo-referenced aerial 

36 photographs, data from the soils survey, a topographic map and state-specific data on 

37 manure application setback requirements. 

38 • Manure Management Planner (MMP) needs data from the soils survey and crop and 

39 climatology data from Natural Resource Conservation Service (NRCS). 
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Chapter 2. Agriculture 2-170 

1 • The data download also includes data needed by the Revised Soil Loss Equation version 

2 2 (RUSLE(2)). 

3 The data-finder packages the data in a compressed file that can be downloaded onto a computer 

4 hard drive. The file is then un-compressed in the same folder on the computer the holds the 

5 working SNMP and MMP files for that farm. This tool will generate a ZIP file containing the 

6 aerial photo image, topographic map image, and soils data needed for SNMP, MMP and 

7 RUSLE(2). The data is obtained from various USDA-NRCS data servers for any area with 

8 spatial data in the NRCS Soils Data Mart (see Status Map). Google Maps is used to locate farms 

9 and define a download area which includes the farm.

10 Link: http://www.nmplanner.missouri.edu/software/national_data.asp AccessedRetrieved

11 January 22, 2010 

12 6. Spatial Nutrient Management Planner—Univ. of Missouri Extension 

13 The Spatial Nutrient Management Planner (SNMP) is a decision support tool that facilitates the 

14 collection, analysis and presentation of spatial data related to nutrient management planning. 

15 Capabilities of SNMP include: 

16 • The SNMP interface simplifies the GIS program ArcMap for nutrient management 

17 planners. 

18 • With a click of a mouse, data can be imported and exported from Purdue’sPurdue's

19 Manure Management Planner (MMP). 

20 • SNMP simplifies the creation of maps required for NRCS comprehensive nutrient 

21 management plans 

22 • Compatibility with NRCS Toolkit 9.x. 

23 Link: http://projects.cares.missouri.edu/snmp/nrcsdata/aoilist.asp AccessedRetrieved January 22, 

24 2010 

25 7. Win Max—Purdue University 

26 WinMax is a computer program developed at Purdue University to calculate and compare 

27 economic returns on crop production. WinMax manages crop input data, calculates crop fertilizer 

28 recommendations, generates production cost and nutrient management worksheets, and allows 

29 sets of custom input costs to be created and used in all calculations. WinMax supports the import 

30 of data from a manure management plan created with MMP, as well as the export of WinMax 

31 data to an MMP plan. Various management options, such as tillage, pest control and fertilizer 

32 strategies, can be compared to help assess which practices are both economically efficient and 

33 environmentally sound. 

34 Link: http://www.agry.purdue.edu/max/ AccessedRetrieved January 22, 2010 

35 8. MapWindow GIS + MMP Tools—Purdue University 

36 MapWindow GIS + MMP Tools is a free GIS that can be used as a front-end to MMP and 

37 WinMax. 
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Chapter 2. Agriculture 2-171 

1 Link: http://www.agry.purdue.edu/mmp/mapwindow/ AccessedRetrieved January 22, 2010 

2 9. Manure Master Decision Support System—USDA-NRCS 

3 This simple screening tool can help assess the relative potential for the nutrients contained in the 

4 animal manure on a farm to meet the crop uptake and use requirements for those crops that 

5 receive applications of manure. Manure Master is an on-farm manure balance tool. It allows 

6 users to compare the nutrient content in the animal manure produced on the farm with the 

7 quantity of nutrients used and removed from the field on which manure is applied. 

8 Manure Master calculates a balance between the N, Pnitrogen, phosphorus, and potassium 

9 content in the manure and the quantity of these nutrients used by crops. This balance can be 

10 calculated based upon recommended fertilizer application rates, when known or upon estimated 

11 plant nutrient content, when recommended fertilizer application rates are not known. For 

12 Nnitrogen, the balance is calculated taking into account expected losses from leaching, 

13 denitrification, and volatilization. 

14 Manure Master produces a report that includes the balance for N, Pnitrogen, phosphorus, and 

15 potassium for these fields. The balance will advise producers of whether the quantity of nutrients 

16 in the animal manure exceeds the quantity removed in harvested plants or the quantity of 

17 nutrients recommended. 

18 Link: http://www2.ftw.nrcs.usda.gov/mm/ AccessedRetrieved January 22, 2010 

19 10. Revised Universal Soil Loss Equation, Version 2 (RUSLE2)—USDA-NRCS 

20 This site contains the official NRCS version of RUSLE2. It is the only version of RUSLE2 to be 

21 used for official purposes by NRCS field offices. The NRCS developed and maintains the 

22 database components on this site. 

23 RUSLE2 is an upgrade of the text-based RUSLE DOS version 1. It is a computer model 

24 containing both empirical and process-based science in a Windows environment that predicts rill 

25 and interrill erosion by rainfall and runoff. The USDA-Agricultural Research Service (ARS) is 

26 the lead agency for developing the RUSLE2 model. The ARS, through university and private 

27 contractors, is responsible for developing the science in the model and the model interface. 

28 Link: http://fargo.nserl.purdue.edu/rusle2_dataweb/RUSLE2_Index.htm AccessedRetrieved

29 January 22, 2010 

30 11. Using RUSLE2 for the Design and Predicted Effectiveness of Vegetative Filter Strips 

31 (VFS) for Sediment—USDA-NRCS 

32 The Revised Universal Soil Loss Equation, Version 2, (RUSLE2) can also be used to design and 

33 predict the expected lifespan of a VFS designed for the purpose of sediment removal based on 

34 the procedures developed by Dillaha and Hayes. The following information is needed: 

35 • Sediment delivery rate at the upper edge of the VFS for the contributing area to the 

36 VFS—calculated by RUSLE2 using the overland flow slope length. 

37 • Sediment Trapping Efficiency—calculated from RUSLE2 results. 

38 • Ratio of Contributing Area to VFS Area. 
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1 This publication requires Microsoft Excel and uses the following spreadsheet: 

2 Filter Strip Life Span Design for Sediment (XLS; 24 KB) 

3 Link: http://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=18578.wba

4 AccessedRetrieved January 22, 2010 

5 Additional Reference: USDA-NRCS. 2007. Agronomy Technical Note No. 2, Using RUSLE2 

6 for the Design and Predicted Effectiveness of Vegetative Filter Strips (VFS) for Sediment, 8pp. 

7 12. Vegetative Filter Strip Modeling System (VFSMOD)—University of Florida 

8 VFSMOD-W is a design-oriented vegetative filter strip modeling system. The MS-Windows 

9 graphical user interface (GUI) integrates the numerical model VFSMOD, a utility to generate 

10 source (upslope disturbed area) inputs for the model based on readily available NRCS site 

11 characteristics (UH), and advanced uncertainty and sensitivity analysis, inverse calibration and 

12 design menu-driven components. VFSMOD, the core of the modeling system, is a computer 

13 simulation model created to study hydrology, sediment and pollutant transport through 

14 vegetative filter strips (VFS). The model is targeted at studying VFS performance on an event15 by-event basis and when combined with the upslope source area input preparation utility (UH or 

16 others like PRZM), becomes a powerful and objective VFS design tool. The design paradigm 

17 implemented in VFSMOD-W seeks to identify optimal filter constructive characteristics (length, 

18 slope, vegetation) to reduce (to a prescribed reduction target like a TMDL) the outflow of 

19 pollutants from a given disturbed area (soil, crop, area, management practices, design storm 

20 return period). 

21 VFSMOD has been tested in a variety of settings (agroforestry, mining and roads) with good 

22 model predictions against measured values of infiltration, outflow, and vegetation trapping 

23 efficiency for sediments, Pphosphorus, and pesticides. Although the model was originally

24 developed as research tool, is now widely used by consultants, planners and regulators to design 

25 optimal filter strips for specific scenarios or to assess effectiveness of existing VFS. 

26 Link: http://carpena.ifas.ufl.edu/vfsmod/ AccessedRetrieved January 28, 2010 

27 13. Integrated Farm System Model (IFSM)—USDA-ARS 

28 The Integrated Farm System Model (IFSM) is a process-based simulation of dairy, beef, and 

29 crop farming systems. This farm model provides a tool for evaluating the long-term 

30 performance, economics, and environmental impacts of production systems over many years of 

31 weather. Environmental impacts include volatile Nnitrogen losses, nitrate loss to ground water, 

32 erosion, soluble and sediment Pphosphorus losses to surface water, and greenhouse gas 

33 emissions. 

34 Link: http://www.ars.usda.gov/Main/docs.htm?docid=8519 AccessedRetrieved January 27, 2010 

35 14. Dairy Greenhouse Gas Model (DairyGHG)—USDA-ARS 

36 The Dairy Greenhouse Gas Model (DairyGHG) is an easy to use software tool that estimates 

37 total greenhouse gas emissions and the carbon footprint of a dairy production system. DairyGHG 

38 uses a relatively simple process-based model to predict the primary GHG emissions from the 

39 production system, which include the net emission of carbon dioxide plus all emissions of 
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1 methane and nitrous oxide. Emissions are predicted through a daily simulation of feed use and 

2 manure handling where daily values of each gas are summed to obtain annual values. A carbon 

3 footprint is then calculated as the sum of both primary and secondary emissions in CO2 

4 equivalent units divided by the milk produced. Secondary emissions are those occurring during 

5 the production of resources used including machinery, fuel, electricity, fertilizer, pesticides, and 

6 plastic. DairyGHG is available for download from our Internet site 

7 (http://ars.usda.gov/naa/pswmru).http://ars.usda.gov/naa/pswmru). The model includes a fully 

8 integrated help system with a reference manual that documents the relationships used to predict 

9 emissions. 

10 Link: http://www.ars.usda.gov/Main/docs.htm?docid=17355 AccessedRetrieved January 27, 

11 2010 

12 15. Cropware—Cornell University Extension 

13 Cropware is used to develop plans in accordance with the NRCS Nutrient Management Standard 

14 (Standard 590), making the output of Cropware a key component of Comprehensive Nutrient 

15 Management Plans. Cornell Cropware integrates the following tools for effective nutrient 

16 management planning: 

17 • Cornell crop nutrient guidelines for a full range of agronomic and vegetable crops. 

18 • Nutrient credits from many sources, including manure, soil, sod, and fertilizer. 

19 • Equations for the conversion of soil test values from other laboratories into Cornell 

20 Morgan equivalents. 

21 • Environmental risk indices, including the New York State Phosphorus Runoff Index and 

22 the Nitrate Leaching Index. 

23 • On-farm logistics, such as manure production, storage, and inventories Report generation 

24 for guiding on-farm implementation. 

25 Link: http://nmsp.cals.cornell.edu/software/cropware.html AccessedRetrieved January 27, 2010 

26 16. Soil Test Conversion Tools—Cornell University Extension 

27 This program converts soil test results from Brookside Laboratories Inc. (Mehlich-3 P, K, Ca, 

28 Mg), Spectrum Analytic Inc. (Mehlich-3 P, K, Ca, and Mg and Morgan P, K, Ca, and Mg), A&L 

29 Laboratories Inc. (Mehlich-3 P, K, Ca, Mg and Modified Morgan P), and the soil testing 

30 laboratories from the University of New Hampshire (Mehlich-3 P, K, Ca and Mg), University of 

31 Massachusetts (Morgan P, K, Ca, and Mg) and the Universities of Vermont and Maine 

32 (Modified Morgan P, K, Ca, Mg) to Cornell University Morgan Equivalents. PPhosphorus

33 conversions from Mehlich-3 data require measured values for soil pH, Mehlich-3 P, Ca, and Al. 

34 For each test, the range of valid input data is given by a minimum value (min) and a maximum 

value (max). Also given are the correlation coefficients (r235 ) for each of the conversion models. 

Conversions with larger r236 values are more reliable. Models were derived using New York soils. 

37 There is uncertainty involved with each of the conversions and we now know there is seasonality 

38 in the conversions with the most reliable conversions obtained when samples are taken after 

39 harvest and before manure application. The user assumes all risk and it is recommended to 

40 submit samples for the Cornell Morgan test to check on the accuracy of the conversion models 
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1 for your farm or the farm you work with. It is also recommended to take 3 subsamples per acre if 

2 you use conversion models to derive Cornell Morgan soil test equivalents. 

3 Link: http://nmsp.cals.cornell.edu/software/conv-tools.html AccessedRetrieved January 27, 2010 

4 17. Great Plains Framework for Agricultural Resource Management (GPFARM)—USDA5 ARS 

6 Great Plains Framework for Agricultural Resource Management (GPFARM) is a simulation 

7 model computer application that incorporates state-of-the-art knowledge of agronomy, animal 

8 science, economics, weed science, and risk management into a user-friendly, decision-support 

9 tool. Producers and others can use GPFARM to test alternative management strategies with 

10 regard to sustainability, pollution reduction, and economic return. 

11 Link: http://www.ars.usda.gov/services/software/download.htm?softwareid=234

12 AccessedRetrieved January 27, 2010 

13 18. Soil - Plant - Atmosphere—Water Field & Pond Hydrology (SPAW)—USDA-ARS 

14 SPAW is a daily hydrologic budget model for agricultural fields and ponds (wetlands, lagoons, 

15 ponds and reservoirs). Included are irrigation scheduling and soil N.nitrogen. Companion models 

16 for soil water characteristics and chemical budgets are included. Data input and results are 

17 graphical screens. 

18 Link: http://hydrolab.arsusda.gov/SPAW/Index.htm AccessedRetrieved January 28, 2010 

19 II. Calculators, Spreadsheets, and Graphical Tools 

20 19. Dairy Cattle N Excretion Calculator—Cornell University Extension 

21 The Dairy Cattle N Excretion Calculator enables users to quickly characterize rations, individual 

22 dairy cattle, and groups of dairy cattle to predict the N partitioned to growth, milk production, 

23 pregnancy, urine, and feces. From there, N use efficiency and N volatilization from the barn 

24 floor are estimated. 

25 Link: http://www.dairyn.cornell.edu/pages/40dairy/420precision/424herdspread.shtml

26 AccessedRetrieved January 27, 2010 

27 20. Corn N Calculator—Cornell University Extension 

28 This calculator factors in soil type, drainage, and other factors to estimate corn N requirements. 

29 Link: http://www.dairyn.cornell.edu/pages/20cropsoil/240guides/245corn.shtml

30 AccessedRetrieved January 27, 2010 

31 21. Total N Available from Manure Applications—Cornell University Extension 

32 NNitrogen from urine (ammonium N) is quickly available for crop uptake, while N from feces 

33 (organic N) is more slowly released. Manure represents a mix of both urine and feces, so 

34 estimations of the amount of plant available N from manure should be based on both. 
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1 The total manure N calculator uses factors such as animal type, percent dry matter, organic N 

2 content, and application rate to estimate the combined contributions of organic N and ammonium 

3 N to the total pool of plant available N from manure. 

4 Link: http://www.dairyn.cornell.edu/pages/20cropsoil/250credits/256totalN.shtml

5 AccessedRetrieved January 27, 2010 

6 22. Other Calculators—Cornell University Extension 

7 This page provides links to calculators for corn N needs, manure nutrients, N credits from 

8 plowed sods, and whole-farm nutrient balancing. 

9 Link: http://nmsp.cals.cornell.edu/software/calculators.html AccessedRetrieved January 27, 2010 

10 23. Nutrient Management Spreadsheets—University of Delaware Cooperative Extension 

11 This page includes links to two spreadsheets, one for estimating animal waste quantity, and the 

12 other for estimating poultry litter quantity. 

13 Link: http://ag.udel.edu/extension/NutriManage/spreadsheets.htm AccessedRetrieved January 

14 27, 2010 

15 24. Crop Nutrient Tool—USDA-NRCS 

16 This is a tool for calculating the approximate amount of N, Pnitrogen, phosphorus, and 

17 potassium that is removed by the harvest of agricultural crops. 

18 Link: http://plants.usda.gov/npk/main AccessedRetrieved January 22, 2010 

19 25. Crop Fertilizer Recommendation Calculator—Purdue University 

20 This calculator is currently supported for DE, MD, and PA. 

21 Link: http://www.agry.purdue.edu/mmp/webcalc/fertRec.asp AccessedRetrieved January 22, 

22 2010 

23 26. Manure Nutrient Availability Calculator—Purdue University 

24 This calculator is currently supported for DE, MD, and PA. 

25 Link: http://www.agry.purdue.edu/mmp/webcalc/nutAvail.asp AccessedRetrieved January 22, 

26 2010 

27 27. Conservation Buffers—USDA National Agroforestry Center 

28 At any given site, the level of pollutant removal from surface runoff depends primarily on buffer 

29 width. The graph and tables at this site can be used to estimate a buffer width that will achieve a 

30 desired level of pollutant removal. The tool is designed to quickly generate estimates of design 

31 width for a broad range of site conditions. Adjustments are made for land slope, soil texture, 

32 field size, and soil surface condition. The tool can be used for sediment, sediment-bound 

33 pollutants, and dissolved pollutants. The tool was developed for agricultural runoff using 
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1 VSFMOD (Vegetative Filter Strip Model), but can be applied in a more general way to other 

2 land uses as well. 

3 Link: http://www.unl.edu/nac/bufferguidelines/guidelines/1_water_quality/19.html

4 AccessedRetrieved January 26, 2010 

5 28. Farm*A*Syst—University of Wisconsin Extension 

6 Farm*A*Syst is a partnership between government agencies and private business that enables 

7 landowners to prevent pollution on farms, ranches, and in homes using confidential 

8 environmental assessments. A system of step-by-step factsheets and worksheets helps 

9 landowners identify the behaviors and practices that create risks associated with livestock waste 

10 storage, nutrient management, wells, hazardous wastes, and petroleum products. 

11 Link: http://www.uwex.edu/farmasyst/ AccessedRetrieved January 27, 2010 

12 III. Compilations of Tools 

13 29. Technical Resources Main Page—USDA-NRCS 

14 This page serves as the gateway to a wide range of technical resources provided by USDA. 

15 Link: http://www.nrcs.usda.gov/technical/

16 30. Animal Feeding Operations (AFO) Virtual Information Center - USEPA 

17 The AFO Virtual Information Center is a tool to facilitate quick access to livestock agricultural 

18 information in the US. This site is a single point of reference to obtain links to state regulations, 

19 web sites, permits and policies, nutrient management information, livestock and trade 

20 associations, federal web sites, best management practices and controls, cooperative extension 

21 and land grant universities, research, funding, and information on environmental issues. The 

22 nutrient management information page has links to nutrient management resources for Delaware, 

23 Maryland, Pennsylvania, Virginia, and West Virginia. 

24 Link: http://cfpub.epa.gov/npdes/afo/virtualcenter.cfm AccessedRetrieved January 28, 2010 

25 31. Software Products—USDA-ARS 

26 This page provides updated information on software tools available from USDA-ARS. 

27 Additional information on ARS models and projects can be found here. 

28 Link: http://www.ars.usda.gov/Services/software/software.htm AccessedRetrieved January 27, 

29 2010 

30 32. Nutrient Management Planning Software and Support—Univ. of Missouri Extension 

31 This page provides links to national resources that facilitate writing a nutrient management plan. 

32 The listed resources contribute to a unified system for writing a nutrient management plan that 

33 meets national standards for NRCS and USEPA. 
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1 a. Nutrient Management Data Download: Use the Nutrient Management Data Finder to 

2 obtain data needed by nutrient management software to complete a plan. 

3 b. Spatial Nutrient Management Planner (SNMP): Use the SNMP to collect and analyze 

4 spatial information and create maps needed for completing a nutrient management plan. 

5 c. Purdue’s Manure Management Planner (MMP): Use MMP to determine fertilizer and 

6 manure application rates and generate the nutrient management plan. 

7 d. Manure Management Planner (MMP) Tutorials: Tutorials on how to use MMP to develop 

8 a swine, poultry or fertilizer only plan. 

9 e. National Setbacks Database: Access a database on the web that reports setback

10 requirements for the 34 states supported by SNMP and MMP. 

11 Link: http://www.nmplanner.missouri.edu/software/ AccessedRetrieved January 22, 2010 

12 IV. Guidance and Other Technical Resources 

13 33. Nutrient and Pest Management Tools and Information - USDA-NRCS 

14 Users will find fact sheets on practices and links to various tools for nutrient and pest 

15 management at this site. 

16 Link: http://www.nrcs.usda.gov/technical/nutrient.html AccessedRetrieved January 26, 2010 

17 34. Conservation Practices—USDA-NRCS 

18 At this site users will find links to the Field Office Technical Guide and the National Handbook 

19 of Conservation Practices. Links to each state’s electronic Field Office Technical Guide 

20 (eFOTG) can be found here. 

21 Link: http://www.nrcs.usda.gov/technical/standards/ AccessedRetrieved January 26, 2010 

22 35. Agronomy and Erosion—USDA-NRCS 

23 This site has links to the National Agronomy Manual, a publication on using RUSLE2 to design 

24 and predict the effectiveness of vegetative filter strips for sediment control, Core 4 Conservation, 

25 and other resources. 

26 http://www.nrcs.usda.gov/technical/agronomy.html AccessedRetrieved January 27, 2010 

27 36. Animal Feeding Operations—USDA-NRCS 

28 This page provides information on CNMPs and links to the MMP and the CNMP field 

29 handbook. 

30 Link: http://www.nrcs.usda.gov/technical/afo/index.html AccessedRetrieved January 27, 2010 
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1 37. Nutrient Management Technical Notes—USDA-NRCS 

2 This page includes links to several fact sheets on diet and feed management for various types of 

3 livestock. The page also includes links for National Conservation Practice Standards for nutrient 

4 management (NRCS Practice Code 590) and waste utilization (NRCS Practice Code 633). 

5 Link: http://www.nrcs.usda.gov/technical/ECS/nutrient/documents.html AccessedRetrieved

6 January 22, 2010 

7 38. National Range and Pasture Handbook—USDA-NRCS 

8 This handbook includes chapters on grazing management and conservation planning for grazing 

9 lands. 

10 Link: http://www.glti.nrcs.usda.gov/technical/publications/nrph.html AccessedRetrieved January 

11 27, 2010 

12 39. Phosphorus Index—USDA-NRCS 

13 This page provides background on the Phosphorus Index, which is intended to provide field 

14 staffs, watershed planners, and land users with a tool to assess the various landforms and 

15 management practices for potential risk of P phosphorus movement to water bodies. 

16 USDA is careful to point out that

17 the phosphorus index is not intended to be an evaluation scale for determining whether 

18 land users are abiding within water quality or nutrient management standards that have 

19 been established by local, state, or federal agencies. Any attempt to use this index as a 

20 regulatory scale would be grossly beyond the intent of the assessment tool and the 

21 concept and philosophy of the working group that developed it. The Phosphorus Index is 

22 proposed to be adapted to local conditions by a process of regional adaptations of the site 

23 characteristic parameters. This local development process must involve those local and 

24 state agencies and resource groups that are concerned with the management of 

25 phosphorus. After the index is adapted to a locality, it must be tested by the development 

26 group to assure that the assessments are giving valid and reasonable results for that 

27 region. Field testing of the index is one of the most appropriate methods for assessing the 

28 value of the index. 

29 Link: http://www.nrcs.usda.gov/technical/ecs/nutrient/pindex.html AccessedRetrieved January 

30 29, 2010 

31 40. SERA-17 Publications and BMP Fact Sheets 

32 SERA-17 is an organization of research scientists, policy makers, extension personnel, and 

33 educators whose mission is to develop and promote innovative solutions to minimize phosphorus 

34 losses from agriculture by supporting:

35 • Informationinformation exchange between research, extension, and regulatory 

36 communities 

37 • Recommendationsrecommendations for phosphorus management and research 
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1 • Initiativesinitiatives that address phosphorus loss in agriculture 

2 Link: http://www.sera17.ext.vt.edu/SERA_17_Publications.htm AccessedRetrieved January 22, 

3 2010 

41. Managing Cover Crops Profitably, 3rd 4 Edition—SARE 

5 This 2007 update from Sustainable Agriculture Research and Education (SARE) includes 

6 information on the benefits of cover crops, selecting cover crops, the use of cover crops with 

7 conservation tillage, crop rotations, and a wide range of legume and non-legume cover crops. 

8 Appendix E contains contact information for regional cover crop experts 

9 Link: http://www.sare.org/publications/covercrops/index.shtml AccessedRetrieved January 27, 

10 2010 

11 42. Precision Feed Management Certification for Dairy Professionals—Mid-Atlantic Water 

12 Program 

13 To In order to help reduce nutrient pollution and implement the NRCS Feed Management 

14 Standard 592, specialists in Pennsylvania, Maryland and Virginia are working with NRCS and 

15 the American Registry of Professional Animal Scientists to develop a process to certify 

16 nutritionists as feed management planners. With few areas in the nation working with the dairy 

17 industry and NRCS on feed management, the Mid-Atlantic is being looked at as a potential 

18 standard for how other states can train nutritionists for a feed management certification and meet 

19 their post-certification, professional needs. This page provides current information on precision 

20 feed management certification, including contact information for leaders from MD, PA, and VA. 

21 Link: http://mawaterquality.org/industry_change/precision_feed_mgmt.html AccessedRetrieved

22 January 27, 2010 

23 43. Mid-Atlantic Better Composting School—Mid-Atlantic Water Program 

24 Since commercial compost can be manufactured from a variety of waste materials, a variety of 

25 standards have been established based on end-uses. Managers of composting facilities 

26 shouldmust be familiar with these standards and with the waste materials and composting 

27 systems that can best produce the desired products. Composting to produce a product that is 

28 consistent in quality will require good management and quality control. 

29 By enrolling in the Mid-Atlantic Better Composing School, participants will not only learn the 

30 basics of making good compost, but they will also have the opportunity to tour commercial 

31 operations, perform product sampling and learn simple procedures for compost testing. 

32 Link: http://mawaterquality.org/industry_change/ma_composting_school.html

33 AccessedRetrieved January 27, 2010 

34 44. Environmental Management System for Manure—Mid-Atlantic Water Program 

35 Members from the Mid-Atlantic Water Program (MAWP) are collaborating with CLEANeast to 

36 assess livestock and poultry operations in sensitive watersheds across PA, MD, and VA using an 

37 Environmental Management Systems (EMS) model. An EMS is a voluntary, flexible business 
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Chapter 2. Agriculture 2-180 

1 management system that helps farmers and managers to develop their own strategies for 

2 integrating environmental considerations into the daily operations of a farm. 

3 By implementing pilot assessments across farms in PA, VA, and MD, team members will 

4 demonstrate how an EMS can not only reduce pollution from farms, but also increase operating 

5 efficiency, achieve public acceptance without regulatory oversight, and elicit confidence in 

6 citizens that the wastes are being handled in an environmentally sound manner. 

7 This page also provides state contacts information.

8 Link: http://mawaterquality.org/industry_change/env_mgmt_system_manure.html

9 AccessedRetrieved January 27, 2010 

10 45. Mid-Atlantic Nutrient Management Handbook—Mid-Atlantic Water Program 

11 The Mid-Atlantic Nutrient Management Handbook was written as a reference text for nutrient 

12 management training programs offered by state regulatory agencies. The Handbook was based 

13 off an earlier nutrient management training manual that was widely used in the Chesapeake Bay 

14 watershed, but revised to incorporate advances in soil, crop, and nutrient management research 

15 and the techniques used to protect surface and groundwater. 

16 Link: http://mawaterquality.org/capacity_building/ma_nutrient_mgmt_handbook.html

17 AccessedRetrieved January 27, 2010 

18 46. Information on Nutrient and Sediment Best Management Practices—Chesapeake Bay 

19 Program 

20 This report led by the University of Maryland Mid-Atlantic Water Program includes nutrient and 

21 sediment reduction effectiveness estimates of select agricultural, stormwater and forestry best 

22 management practices (BMPs). With funding from the Chesapeake Bay Program Office, the 

23 Mid-Atlantic Water Program developed definitions and effectiveness estimates for BMPs that 

24 states were implementing or proposing to implement as part of their efforts to meet the nutrient 

25 and sediment reduction goals necessary to restore the Bay. The report provides realistic, science26 based estimates of expected nutrient and sediment reduction performance from these BMPs and 

27 reflects current research and knowledge as well as average operational conditions representative 

28 of the entire Chesapeake Bay Watershed. 

29 Link: http://www.chesapeakebay.net/marylandbmp.aspx?menuitem=34449 AccessedRetrieved

30 January 27, 2010 

31 47. Fact Sheets—University of Delaware Cooperative Extension 

32 This page contains links to several fact sheets on nutrient management, poultry litter 

33 management, and animal waste management. 

34 Link: http://ag.udel.edu/extension/NutriManage/publications.htm AccessedRetrieved January 27, 

35 2010 
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1 48. Nutrient Management—Maryland Department of L., J. A. Nienaber, et al. (2003). 

2 Performance of a passive feedlot runoff control and treatment system. Transactions of the 

3 ASAEAsae 46(6): 1525–-1530. 

4 Ladha, J.K., Pathak, H., Krupnik, T.J., Six, J. and van Kessel, C. 2005. Efficiency of fertilizer 

5 nitrogen in cereal production: retrospects and prospects. Advances in Agronomy 87:85-156. 

6 Mosier, A.R., J.K. Syers, and J.R. Freney. 2004. Ch. 1-Nitrogen fertilizer: an essential 

7 component of increased food, feed, and fiber production. pp. 3-15. In A.R. Mosier, J.K. 

8 Syers, and J.R. Freney (eds.). Agriculture and the Nitrogen Cycle. Assessing the impacts 

9 This page provides various links to nutrient management fact sheets, recommendations, and 

10 training opportunities. 

11 Link: http://www.mda.state.md.us/resource_conservation/nutrient_management/index.php

12 AccessedRetrieved January 27, 2010 

13 49. Nutrient Management Program—University of Maryland Extension 

14 The Agricultural Nutrient Management Program is a component of the University of 

15 Maryland’sMaryland's College of Agriculture and Natural Resources Nutrient Management 

16 Programs and focuses on reducing the pollution of the Chesapeake Bay by plant nutrients from 

17 cropland. The Program provides nutrient planning services to Maryland farmers via a network of 

18 nutrient management advisors located in all county Extension offices and provides continuing 

19 education and technical support to certified nutrient management consultants via state and 

20 regional nutrient management specialists. 

21 One of these services is the development of nutrient management plans, which are documents 

22 that incorporate soil test results, yield goals, and estimates of residual Nnitrogen to generate 

23 field-by-field nutrient recommendations. 

24 Link: http://anmp.umd.edu/ AccessedRetrieved January 27, 2010 

25 50. Nutrient Management Plan Writing Tools—University of Maryland Extension 

26 A nutrient management plan is a formal document that balances crop nutrient needs with 

27 nutrients that are applied in the form of commercial fertilizer, animal manure, or biosolids. The 

28 plan contains soil test results, manure and biosolids analyses (where applicable), yield goals, and 

29 estimates of residual Nnitrogen to generate field-by-field nutrient recommendations. The 

30 following information sheets and work sheets will help producers in the plan writing process. 

31 Link: http://anmp.umd.edu/Plan/Plan_Writing.html AccessedRetrieved January 27, 2010 

32 51. Phosphorus Site Index—University of Maryland Extension 

33 The Phosphorus Site Index, or PSI, is an integral part of a nutrient management plan. If a 

34 producer intends to add Pphosphorus in commercial or organic forms (including starter fertilizer) 

35 to a field and the soil test indicates a Pphosphorus fertility index value (FIV-P) of 150 or more 

36 for that particular field, then the PSI should be calculated. The PSI takes into consideration 

37 Pphosphorus loss potential due to site and transport characteristics and management and source 

38 characteristics. 
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1 Link: http://anmp.umd.edu/PSI/PSI.html AccessedRetrieved January 27, 2010 

2 52. Nutrient Management Software and Publications—University of Maryland Extension 

3 This page provides summary information and links to available publications and software for 

4 nutrient management in Maryland. 

5 Link: http://anmp.umd.edu/Pubs/Pubs.html AccessedRetrieved January 27, 2010 

6 53. Nutrient Management Spear Program—Cornell University 

7 The vision of the Cornell University’sUniversity's Nutrient Management Spear Program is to 

8 assess current knowledge, identify research and educational needs, conduct applied, field and 

9 laboratory-based research, facilitate technology and knowledge transfer, and aid in the on-farm 

10 implementation of strategies for field crop nutrient management, including timely application of 

11 organic and inorganic nutrient sources to improve profitability and competitiveness of New York 

12 State farms while protecting the environment. 

13 This page has links to a variety of nutrient management resources, including nutrient guidelines, 

14 Nnitrogen management, and the New York State Phosphorus Runoff Index. These links provide 

15 additional links to tools and resources such as Cropware and other nutrient management 

16 calculators. 

17 Link: http://nmsp.cals.cornell.edu/index.html AccessedRetrieved January 27, 2010 

18 54. Manure Management—Penn State College of Agricultural Sciences 

19 This page provides information on manure management at animal operations, including links to 

20 information specific to Pennsylvania. 

21 Link: http://www.das.psu.edu/research-extension/nutrient-management/manure

22 AccessedRetrieved January 27, 2010 

23 55. Pennsylvania Nutrient Management Program—Penn State University 

24 This web site provides a comprehensive source of information about 

25 Pennsylvania’sPennsylvania's Nutrient Management Act (Act 38, 2005) Program, and associated 

26 technical guidance and educational information. It also provides limited information concerning 

27 related programs. The web site has been developed and is maintained through a workgroup 

28 representing various partnering agencies actively involved with the Pennsylvania Nutrient 

29 Management Act Program. Contributions to this site represent the collective efforts of that 

30 workgroup 

31 Link: http://panutrientmgmt.cas.psu.edu/ AccessedRetrieved January 27, 2010 

32 56. Planning Tools and Resources—Penn State University 

33 This page provides links to the nutrient management plan standard format, a nutrient balance 

34 spreadsheet, the Pennsylvania Phosphorus Index spreadsheet, a pasture nutrient calculator, and 

35 other resources associated with nutrient management in Pennsylvania. Contained within the 

36 Phosphorus Index spreadsheet is contact information for state experts. 
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Chapter 2. Agriculture 2-183 

1 Link: http://panutrientmgmt.cas.psu.edu/main_planning_tools.htm AccessedRetrieved January 

2 27, 2010 

3 57. Nutrient Management Technical Manual—Penn State University 

4 This is the technical manual for Pennsylvania’s Nutrient Management Act Program. 

5 Link: http://panutrientmgmt.cas.psu.edu/main_technical_manual.htm AccessedRetrieved January 

6 27, 2010 

7 58. Educational Materials—Penn State University 

8 This page provides links to fact sheets and publications addressing of wide range of topics 

9 associated with nutrient management and manure management in Pennsylvania. 

10 Link: http://panutrientmgmt.cas.psu.edu/em_publications.htm AccessedRetrieved January 27, 

11 2010 

12 59. Fact Sheets on Agriculture and Environmental Quality—Virginia Tech Extension 

13 The page provides links to fact sheets covering a range of topics including composting, 

14 Pphosphorus management, and livestock exclusion. 

15 Link: http://pubs.ext.vt.edu/category/environmental-quality.html AccessedRetrieved January 27, 

16 2010 

17 60. Virginia Agricultural BMP Cost Share and Tax Credit Programs—Virginia 

18 Department of Conservation and Recreation 

19 This page provides information and links associated with agricultural BMPs in Virginia, 

20 including the Virginia agricultural BMP manual and BMP cost-sharing. 

21 Link: http://www.dcr.virginia.gov/soil_and_water/costshar.shtml AccessedRetrieved January 27, 

22 2010 

23 61. Nutrient and Waste Management—West Virginia University Extension Service 

24 This page provides links to nutrient management training courses including the P index, 

25 information on nutrient management consultant certification, manure sampling and analysis 

26 methods, and related websites. 

27 Link: http://www.wvu.edu/~agexten/wastmang/index.html AccessedRetrieved January 28, 2010 

28 62. Comprehensive Livestock Environmental Assessments and Nutrient (CLEANEast) 

29 Management Plan program—RTI International and North Carolina State University 

30 CLEANEast provides confidential, free technical support to farms including beef, dairy, swine, 

31 or poultry operations located in 27 eastern states. It helps farm operators identify and implement 

32 farm management practices that protect the environment. CLEANEast is a voluntary program 

33 that farm operators can apply to for on-site support services from a qualified Technical 

34 Assistance Professional to: 
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Chapter 2. Agriculture 2-184 

1 • Conduct an Environmental Assessment

2 • Update an existing Nutrient Management Plan

3 • Prepare a new Nutrient Management Plan

4 Link: https://livestock.rti.org/ AccessedRetrieved January 28, 2010 

5 63. Comprehensive Nutrient Management Planning (CNMP) - eXtension 

6 The details of a Comprehensive Nutrient Management Plan (CNMP) are described at this site, 

7 including links to various handbooks and guidance documents important to the development of a 

8 CNMP for an animal feeding operation. For example, a key objective of a CNMP is to document 

9 the plans of an animal feeding operation owner/operator to manage manure and organic by10 products in combination with conservation practices and facility management activities to protect 

11 or improve water quality. NRCS has listed six elements of a CNMP that should be considered 

12 during preparation of the plan, though a CNMP is not required to contain all six elements. The 

13 components that should be considered are: 

14 • Manure and Wastewater Storage and Handling 

15 • Land Treatment Practices 

16 • Nutrient Management 

17 • Record Keeping 

18 • Feed Management 

19 • Other Utilization Activities 

20 A complete description of these elements, and what each element specifically covers, is included 

21 in the USDA-NRCS National Planning Procedures Handbook (Part 600.5). Users should check 

22 with their agriculture and natural resources agencies to see if their state has its own specific 

23 CNMP requirements and guidance. 

24 Link: 

25 http://www.extension.org/pages/Comprehensive_Nutrient_Management_Planning_%28CNMP%

26 29 AccessedRetrieved January 22, 2010 

27 64. CNMP Core Curriculum—Iowa State University 

28 There are several sources for additional information about CNMPs. Many land grant universities 

29 and other commodity/producer organizations provide informational literature and websites. 

30 Additionally, state NRCS offices often maintain CNMP/TSP informational web pages. A source 

31 of information about CNMPs is the CNMP Core Curriculum training modules maintained by 

32 Iowa State University and available through the Midwest Plan Service. The CNMP Core 

33 Curriculum is also a good resource for educators interested in providing training on CNMP 

34 development. Also, the breadth of information covered in the topic areas make the curriculum a 

35 good source of materials for smaller scale trainings, such as shorter, topic specific extension 

36 programs. The CNMP Core Curriculum provides a consistent background and framework from 

37 which state or regionally specific CNMP courses can be developed. There are ten sections in the 

38 Comprehensive Nutrient Management Plan (CNMP) Core Curriculum. The section topics are: 
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Chapter 2. Agriculture 2-185 

1 • Introduction to a Comprehensive Nutrient Management Plan 

2 • Conservation Planning 

3 • Land Treatment Practices 

4 • Manure and Wastewater Storage and Handling 

5 • Nutrient Management 

6 • Feed Management 

7 • Record Keeping 

8 • Air Quality 

9 • Alternative Utilization 

10 • TSP Certification 

11 Link: http://www.abe.iastate.edu/wastemgmt/cnmp-curriculum.html Accessedretrieved January 

12 26, 2010 

13 65. Manure Management Planner Tutorials—Univ. of Missouri Extension 

14 These tutorials were part of a training program for Missouri nutrient management planners. The 

15 tutorials outline many of the steps in developing a nutrient management plan in MMP. Many of 

16 the steps in using MMP are universal among all states. These tutorials were developed in 2005 

17 for an earlier version of MMP, but the authors believe that the tutorials are still mostly applicable 

18 to the planning process when using MMP. Separate tutorials were developed for a swine 

19 operation (liquid manure), poultry operation (solid manure) and fertilizer plan (no manure). 

20 Link: http://www.nmplanner.missouri.edu/software/mmp_tutorial.asp AccessedRetrieved

21 January 22, 2010