FY2010 Annual Report 

National Program 212 – Climate Change, Soils, and Air Emissions

Introduction

National Program (NP) 212 Climate Change, Soils and Air Emissions supports research to 

improve the quality of atmosphere and soil resources that both affect and are affected by 

agriculture, to understand the effects of climate change on agriculture, and to prepare 

agriculture for adaptation to climate change. 

Agricultural systems function within the soil-atmosphere continuum. Mass and energy 

exchange processes occur within this continuum and agriculture can significantly affect the 

processes. Emissions from agriculture to the atmosphere affect air quality and increase 

atmospheric greenhouse gas (GHG) concentrations. While GHG emissions are a part of the 

natural cycling of carbon (C) and nitrogen (N), these emissions also contribute to climate 

change. A changing climate impacts agriculture, range and pasture systems, and soils through 

alterations of precipitation and temperature patterns, and increased atmospheric carbon 

dioxide (CO2) concentration. The impacts of climate change create challenges to agriculture 

and ecosystem services, but also offer new opportunities for agricultural production and 

enhancement of soil quality. 

Soils are a crucial boundary resource between agriculture and the atmosphere. Soils in 

agricultural systems must be managed to meet rising global demands for food, feed, fiber, fuel 

and ecosystem services while maintaining soil productivity and limiting undesirable 

interactions between soils and the atmosphere. Soil degradation through erosion and 

decreased physical (e.g., structure, compaction, infiltration), chemical (e.g., acidification, 

salinization, nutrient depletion), and biological (e.g., biodiversity, nutrient cycling, soil 

organic matter) properties and processes must be mitigated to ensure critical goods and 

services provided by soil resources are maintained. New approaches to managing and 

improving soil resources coupled with the significant strides being made to develop new

varieties of crops via genomics, offer great potential for meeting these rising global demands. 

The variability of the atmosphere, soils, and plants, and the complexity of interactions among 

these systems require collaborations by ARS scientists conducting NP212 research. Formal 

and informal Cross Location Research (CLR) projects including the Greenhouse gas 

Reduction through Agricultural Carbon Enhancement network (GRACEnet), the Renewable 

Energy Assessment Project (REAP), and field campaigns focused on air quality are successful 

examples. Synthesis and integration of information, including sources outside NP212, by 

CLR projects increases the utility and impact of ARS research. Efficient assimilation of data 

from NP212 projects into existing and future collaborative databases will enhance synthesis 

and integration analyses and expand research opportunities.

Research reports are organized according to the Research Components of the NP212 Action 

Plan:
1. Enable Improvements of Air Quality via Management and Mitigation of Emissions 

from Agricultural Operations

2. Develop Knowledge and Technologies for Reducing Atmospheric Greenhouse Gas 

Concentrations Through Management of Agricultural Emissions and Carbon 

Sequestration

3. Enable Agriculture to Adapt to Climate Change

4. Maintaining and Enhancing Soil Resources

Research under the first component was formerly conducted and reported under NP203 Air 

Quality. The second component is focused on mitigation of climate change while the third 

component is focused on adaptation to climate change. Research on climate change was 

formerly conducted and reported under NP204 Global Change. The fourth component 

encompasses research that was formerly conducted under NP202 Soil Resource Management. 

All of the research conducted under NP 212 Climate Change, Soils and Air Emissions, uses

the approaches of:

• Understanding and measuring the important factors, 

• Modeling or enabling prediction of process outcomes using measureable factors as 

inputs,

• Enabling management of factors and conditions affecting processes to achieve desired 

solutions or improvements.

Working groups of ARS scientists from different geographic locations and ARS National 

Programs contribute to the objectives of climate change, air quality and soils research. 

The November/December 2009 Agricultural Research Magazine was a special issue devoted 

largely to climate change. This issue contains eight articles that provide a good representative 

sample of the types of climate change research that ARS conducts. An electronic version of 

this issue can be downloaded from http://www.ars.usda.gov/is/AR/archive/nov09/.

Component 1: Enable Improvements of Air Quality via Management and Mitigation of 

Emissions from Agricultural Operations

Atmospheric emissions from agriculture are under increased scrutiny due to potential negative 

environmental effects and threats to human and animal welfare. Emissions contribute to 

tensions between agriculture and residential communities from visibility impairment (haze) 

and nuisance odors. Major classes of emissions include particulate matter (PM), volatile 

inorganic compounds (primarily ammonia and hydrogen sulfide), volatile organic compounds 

(VOCs), and those from pesticides. Often these emissions exist as mixtures and, thus, 

adjustments to production practices for abatement may decrease the release of one material 

while changing the emission character or magnitude of other materials.

An ARS Air Quality Researchers Working Group has been formed to better coordinate 

agricultural air quality research activities, stewardship of research data, and delivery of 

information and research products to producers and policy-makers. Information exchange and 

collaboration is currently underway with USDA- Natural Resources Conservation Service 
(NRCS), University researchers, EPA, NOAA, and NASA. The ARS Air Quality research 

community also regularly communicates with the Agricultural Air Quality Task Force 

convened by NRCS. 

Selected Accomplishments: Air Quality Research

Simplified method for determining the susceptibility of soils to wind erosion. The wind 

erodible fraction (WEF) is a measure of the susceptibility of soils to erosion by wind and 

provides a useful tool for planning farming production strategies. The standard method for 

measuring WEF uses a laboratory-based rotary sieve that requires transportation of soil 

samples to the laboratory. Unfortunately, soils tend to break up during transport to the 

laboratory, yielding erroneous results. A rapid and simple field-based sieving protocol for 

determining WEF was developed by ARS researchers in Manhattan, KS. The protocol was 

described in a report delivered to NRCS and is now being used by NRCS in the field on a 

limited test-basis as a quick method for determining temporal WEF. This method is also

being incorporated into the NRCS National Agronomy Manual of policy and procedures for 

wind erosion. NRCS is now better-equipped to help landowners increase air quality and 

improve soil sustainability via reductions of wind-eroded soil. 

New method to "fingerprint” particulate matter emitted from cattle feedlots. Current 

methods to evaluate particle concentrations from cattle feedlots fail to identify the sources, 

thus limiting progress towards strategies to reduce particulate emissions. Using Raman 

microscopy methods, ARS scientists from Beltsville, MD examined the chemical profile of 

individual particles captured downwind from a cattle feedlot and compared them with the 

chemical profiles of particles taken from potential sources within the feedlot. Positive 

matches enabled sourcing of airborne samples to a specific location within the field lot. This 

approach can be used to determine the most important sources of particles to the total particle 

emission flux. Detailed information on particle sources will be useful for evaluating the 

efficacy of existing and future improved dust management practices.

New model for estimating ammonia emissions from dairy manure. There is a need to 

update tools for predicting ammonia emissions from dairy livestock manure, as existing 

models are based upon old data from obsolete dairy facilities. ARS scientists at University 

Park, PA collected data from a range of modern dairy facilities and developed new equations 

that were found to better estimate ammonia emissions from dairies currently being operated. 

The new findings are being integrated into a decision support tool that will enable producers 

to evaluate the effects of nitrogen management and thus ammonia mitigation strategies, on the 

total air emissions from farms. Use of the updated decision support tool enables increased 

nitrogen use efficiency, which in turn reduces ammonia emissions and can increase profit 

margins. Reducing ammonia emissions improves both air, and water quality via reduced 

deposition of atmospheric nitrogen. 

Rapid assay for prediction of residue decomposition. Wheat and barley cultivars that do 

not rapidly decompose have hindered the implementation of conservation farming systems 

and reduced-till and no-till seeding in the dryland Pacific Northwest. These practices, once 

implemented, can reduce soil erosion, which degrades air quality. Additional knowledge on 
cereal straw decomposition is needed to help growers design crop rotations that promote the 

adaptation of reduced-till and no-till seeding. ARS scientists in Pullman, WA, in collaboration 

with Washington State University scientists, have developed a quick method using nearinfrared technology to identify the fiber and nutrient composition of spring wheat, winter 

wheat and spring barley straw, and predict straw decomposition in different cultivars. 

Information on differences in straw decomposition among wheat and barley cultivars will 

help growers select cultivars for reduced tillage systems. 

Component 2: Develop Knowledge and Technologies for Reducing Atmospheric

Greenhouse Gas Concentrations through Management of Agricultural Emissions and 

Carbon Sequestration

Agricultural GHG emissions to the atmosphere are among the documented anthropogenic 

factors driving climate change. Of critical importance to GHG reductions and improved 

efficiency of fertilizer management is the reduction of nitrous oxide (N2O), as agriculture is 

the largest anthropogenic source of this GHG. Land management practices may be altered to 

reduce GHG emissions. Agriculture also provides an opportunity to sequester C in soils, thus 

offsetting GHG emissions and offering a partial solution to slowing the forces of climate 

change.

ARS has made significant contributions to the recently-released USDA Climate Change 

Science Plan (available 

from: http://www.usda.gov/oce/climate_change/science_plan2010/USDA_CCSPlan_112910.

pdf ),

and to USDA efforts to develop programs promoting carbon sequestration and GHG emission 

reductions. The nationwide ARS Greenhouse gas Reductions through Agricultural Carbon 

Enhancement network project 

(GRACEnet: http://www.ars.usda.gov/research/programs/programs.htm?np_code=212&docid

=21223) continues to provide critically-needed information to enable agriculture to reduce its 

impact on climate via GHG emission reductions, and to reduce atmospheric greenhouse gas 

concentrations through soil carbon enhancement. 

ARS also supports the U.S. role in the Global Research Alliance on Agricultural Greenhouse 

Gases (“GRA”), an international effort to reduce agricultural greenhouse gas emissions that 

was endorsed by Agriculture Secretary Vilsack during the Copenhagen climate change 

meetings in December, 2009. ARS scientists provide the international coordination for the 

GRA Croplands Research Group, represent the U.S. in the GRA Paddy Rice Research Group

and have contributed to the US contributions to the GRA Livestock Research Group.

Selected Accomplishments: Climate Change Mitigation Research

Influence of nitrogen fertilizer forms on greenhouse gas emissions from corn depends on 

production and environmental conditions. A significant source of nitrous oxide (N2O), a 

greenhouse gas with significantly greater impact on climate change than carbon dioxide 

emissions, is from the use of nitrogen (N) fertilizers. Use of enhanced-efficiency N fertilizers 
(controlled release and stabilized nitrogen sources) was shown to influence the amount of 

N2O emitted from irrigated no-till corn. In no-till irrigated corn in the semiarid western U.S., 

nitrous oxide emissions monitored by ARS scientists in Fort Collins, CO during the 2007 and 

2008 growing seasons were reduced up to 53% by the use of enhanced-efficiency N fertilizers 

when compared to dry granular urea, and up to 35% when compared to liquid ureaammonium nitrate fertilizers commonly used by farmers. In another study, ARS researchers 

in Ames, IA tested the use of stabilized nitrogen fertilizer as a means of reducing nitrous 

oxide (N2O) greenhouse gas emissions from a non-irrigated corn crop; in that case, N2O 

emissions were not reduced, but crop yield was increased. In the Iowa experiment, the 

stabilized materials appeared to affect the nitrate and ammonium pools in the soil through a 

reduction of ammonia volatilization when the materials are applied; the increase in crop yield 

reflected an increase in nitrogen availability during the grain-filling period as these plants 

showed a greater amount of leaf greenness, larger grain size and ultimately larger crop yield. 

Thus, for temperate climates, the soil water balance is a dominant factor affecting N2O 

emissions, and that changing forms of nitrogen to include stabilized materials could have a 

yield advantage but not necessarily a greenhouse gas emission advantage. Together, the two 

studies provide important early steps towards regional-specific guidelines for reduction of 

greenhouse gases from agricultural sources, while maintaining or increasing crop yields. 

An improved remote sensing method for assessing crop residue cover. Crop residue 

cover, a product of low-till and no-till farming, is an important tool for controlling soil erosion,

enhancing soil productivity and increasing soil carbon sequestration. Current methods of 

measuring residue cover for management decisions are inadequate for characterizing the 

spatial variability of residue cover over many fields. Measurements based on Landsat satellite 

data for mapping residue cover are often confounded by changes in how the soil itself reflects 

light. There are reliable ways to get the data based on very narrow ranges of reflected 

wavelengths, but that kind of imagery is expensive and not widely available. An alternative 

approach was proposed and tested at five locations in the U.S. on multiple dates. Results 

show that a minimal upgrade from one broad Landsat wavelength band to two or three 

relatively narrow bands would provide reliable estimates of crop residue cover and soil tillage 

intensity data for regional assessments of conservation practices. This work advances crop 

residue mapping, as well as biogeochemical models that produce credible estimates of soil 

carbon at watershed and regional scales. 

Methods for rapid measurement of soil organic carbon (SOC) and SOC pools assessed.

A quick, reliable method to measure SOC is required for assessing large numbers of soil 

samples needed to characterize the SOC of whole fields and landscapes. The data is needed 

for management decisions, verification of C states for environmental credit trading, and 

validation of C models. The methods tested for rapid measurement of SOC included use of 

near- and mid-infrared measurements and pyrolysis molecular beam mass spectrometric 

(pyMBMS) analyses. ARS scientists from Fort Collins, CO, used methods that were 

calibrated and/or compared to traditional laboratory methods to measure the total SOC, 

microbial biomass C, particulate organic matter C, mineral associated C, soil inorganic C 

(SIC). The results of these studies show that mid-infrared methods were superior to nearinfrared methods for measuring total SOC and microbial biomass C. The mid-infrared method 

had the advantage of being more sensitive for some measures, while the pyMBMS method 
allowed an evaluation of the organic molecules that were associated with various SOC pools, 

thus possibly helping to identify pathways for C cycling and sequestration. These findings 

provide a step towards the development of rapid and potentially mobile methods of reliably 

assessing the effectiveness of soil carbon management. 

Soil conditioning index (SCI) calibrated to soil organic carbon for Southeastern U.S. 

Rapid and reliable assessments of the potential for agricultural management systems to 

sequester SOC are needed to promote conservation and mitigate GHG emissions. A 

collaborative effort to investigate the validity of the soil conditioning index for prediction of 

soil organic carbon sequestration was developed among scientists with ARS in Watkinsville, 

GA, a former ARS research associate in Beltsville, MD (now at the National University in 

Asuncion, Paraguay), and with Natural Resource Conservation Service (NRCS) in Temple, 

TX. Published measurement of SOC from various studies throughout the southeastern U.S.

were compared with computer simulations of SOC based on the soil conditioning index and 

the Revised Universal Soil Loss Equation. Within a field study, the soil conditioning index 

was usually highly related to SOC content. Across studies, SOC would increase by 0.25 tons 

of carbon dioxide per acre per year per unit change in Soil Conditioning Index (SCI). These 

results will have important implications for farmers, crop advisors, scientists, and policy 

makers interested in carbon trading schemes throughout the 300 million acres of land in the 

southeastern U.S. 

Component 3: Enable Agriculture to Adapt to Climate Change

Mechanisms for adapting to climate change are critical for continued agricultural production 

and stewardship of natural resources. An understanding of the impacts of climate change on 

natural and managed ecosystems provides insights needed to formulate strategies for 

addressing vulnerabilities and exploiting potentially beneficial aspects of climate change. 

Mechanisms for identifying and detecting indicators of impacts are key to formulating 

management responses. Adaptive responses to climate change must be evaluated for impacts 

on ecosystem function and potential feedbacks on the climate system and subsequent 

consequences for sustainability and reinforcement, or offset of, climate change mitigation 

strategies.

ARS conducts research under Natural Resources and Sustainable Agriculture Systems, Crop 

Production and Protection, Animal Production and Protection, and Nutrition, Food 

Safety/Quality that contributes to the resiliency of agriculture to the effects of changing 

climate. The accomplishments listed below focus on those from Natural Resources and 

Sustainable Agriculture Systems projects.

Selected Accomplishments: Climate Change Adaptation Research

Rising atmospheric CO2 favors weedy rice over cultivated rice. Rising atmospheric CO2

increases the growth of many crops and enhances the growth of many weeds. Weedy red rice 

is a troublesome weed in cultivated rice fields that reduces the quantity and quality of rice 

harvested for food. Research showed that weedy red rice growth increased more with 
additional CO2 than cultivated rice. Further, higher CO2 increased the ability of weedy red

rice to compete with cultivated rice, to the detriment of rice yield. These results document 

greater susceptibility of rice production to in-field competition from greater weed vigor driven 

by rising atmospheric CO2, and highlight the need to assess the combined impacts of 

increasing atmospheric CO2 and rising air temperatures on global rice production. 

Predicting plant invasions in an era of global change. Global change is expected to 

dramatically alter invasive plant occurrences and will require corresponding changes of land 

management. ARS scientists from Cheyenne, WY and Ft. Collins, CO, collaborated with two 

Princeton University scientists to provide a new framework for examining this issue in an 

invited review and synthesis article. Supported by findings from both modeling and 

experimental studies, the scientists concluded that global changes that increase the availability 

of plant resources, such as atmospheric CO2 enrichment and N pollution, are most likely to 

cause plant invasion. They proposed management changes needed to combat invasive plants 

in the face of global change. This work will be used extensively, both by global change 

biology researchers to better understand climate change impacts on ecosystems, and by 

managers of natural and semi-natural ecosystems. 

Effects of elevated CO2 on crop yield evaluated. At least nine research groups from around 

the world have conducted FACE (free-air CO2 enrichment) experiments on ten or more crops 

over the last two decades to determine how increasing concentration of atmospheric CO2 will 

likely affect future crop yields. An ARS scientist from the U.S. Arid-Land Agricultural 

Research Center, Maricopa, AZ analyzed the collective results of these experiments and 

concluded that yields of sorghum, a C4 crop, were unaffected, whereas yields of C3 crops 

were increased 16 to 40 percent under atmospheric CO2 concentrations of roughly 550 ppm. 

For example, yields of C3 grain crops (wheat, rice, barley, soybean) were increased roughly 

17 percent on average. Results from the China FACE Rice Project showed 32 percent 

increases for some hybrid rice varieties. These results show that given minimal climatic 

change impacts of increasing temperature, changing water availability, etc., future C3, but not 

C4, crop yield will increase due to the effects of elevated atmospheric CO2 on plants. Given 

detrimental impacts of increasing temperature, changing water availability, etc., these direct 

CO2 effects will tend to mitigate the harm. The results are critically important for estimating 

future food production and offer insights for potential changes to agricultural systems needed 

to increase world food production. 

Incidence of forest diseases decreased on plants exposed to elevated atmospheric carbon 

dioxide. Plant diseases cost growers billions of dollars each year in control and lost 

productivity. Understanding how the rising level of atmospheric carbon dioxide may alter 

incidence and severity of important plant diseases is crucial to future management strategies. 

ARS researchers in Auburn, AL determined that the incidence of both pitch canker and 

fusiform rust were lower on loblolly pines grown under elevated carbon dioxide; fusiform rust 

took longer to develop on red oak seedlings exposed to elevated carbon dioxide; and carbon 

dioxide did not affect disease severity. Data suggests that some plants may benefit from the 

rising level of carbon dioxide through decreased fungal disease incidence. This information 

provides insights to the susceptibility and resilience of plants to changing climatic conditions 

and can be used to plan for plant disease risk management planning. 
Atmospheric CO2 enrichment increases root biomass of a grassland ecosystem. Most 

organic carbon in grasslands resides in soil, having been derived from plant roots. This pool 

of C may increase and thereby slow the accumulation of CO2 in air if increasing CO2

stimulates root production without a compensating increase in the rate at which soil organisms 

decompose dead roots. ARS researchers at Temple, TX, together with collaborators from 

Duke University, measured root biomass in grassland communities exposed to a continuous 

gradient in atmospheric CO2 spanning pre-Industrial conditions to elevated concentrations. 

Increasing CO2 caused a significant increase in root biomass of plant communities, with linear 

or curvilinear responses to CO2 depending on sampling date. Carbon dioxide enrichment 

reduced the lifespan of roots of the dominant perennial grass when neighboring roots were 

frequent, implying that CO2-enriched plants readily shed or turnover roots located in zones of 

dense root growth. The results indicate that increasing CO2 concentration may increase soil C 

storage in grassland ecosystems by stimulating root production and turnover. This information 

provides a useful selection criterion for the development of new grass varieties optimized for 

C sequestration.

Component 4: Maintaining and Enhancing Soil Resources

The thin layer of soil at the surface of the earth functions as the central resource for sustaining 

life. Soil management is one of the critical factors controlling plant production, which in turn 

supports animal production. Soils also remove impurities, protecting water and air quality. A 

balance must be reached between the short-term use of the soil and the long-term 

sustainability of this critical resource. Protecting, preserving, and enhancing the soil resource 

are key elements of this component of the NP212 National Program.

Research is conducted to understand soil physical, chemical, and biological properties and 

processes, to facilitate the development of soil management practices that overcome 

limitations to productivity and to improve soil, water and air quality. However, an increasing 

emphasis will be placed on understanding the ecology of the soil/water/plant system and 

enhancing the health, quality, and environmental services provided by soils. 

Review articles in Science magazine and a 2009 report on Frontiers in Soil Science by the 

National Academy of Sciences have drawn attention to the importance of the soil resource 

and to our incomplete knowledge of soil properties, processes and functions. Considerable 

research will be needed to support management practices and systems that can overcome soil 

limitations to crop production and provide soil, water and air quality benefits. 

Selected Accomplishments: Soils Research

Herbicides affect nutrient cycling. Farmers have observed symptoms of nutrient deficiency 

in crops where the herbicide glyphosate has been used for several years in a row. ARS 

scientists in West Lafayette, IN found that one reason for this is that long-term exposure to 

glyphosate affects soil enzyme activities that are critical in nutrient cycling. Depending on 

how widespread this impact is, these findings could impact fertilizer application rate and 

weed management decision making for some crop-soil type combinations. 
No evidence found that Bt corn residues decompose more slowly than Non-Bt residues. 

Since Bt corn was introduced, there have been informal and formal communications 

circulating in the agricultural community that Bt corn residues were more resistant to 

decomposition than non-Bt corn residues. ARS scientists at Brookings, SD, have completed a 

series of studies that found no evidence that the decomposition of corn residues was linked to 

the presence of the Bt gene in the corn hybrid. These studies examined multiple corn hybrids 

from a single manufacturer, hybrids from different seed manufacturers, and hybrids grown 

under conditions of differential insect pressure. With the rapid expansion of geneticallymodified crops, controlled studies evaluating the potential for unintended effects due to 

genetic modification provide a firm basis for evaluating the advantages and disadvantages of 

this technology. 

Fungicide use substantially slows degradation of a widely used weed control product. 

Pesticides are a diverse group of chemicals including products used to control weeds 

(herbicides), plant diseases (fungicides), and insects (insecticides). During large-scale 

production of most crops, pesticides from one or more of these classes are applied to farm 

fields. A common scenario in peanut production in the southeastern U.S. is herbicide 

application at planting followed by fungicide applications after the crop emerges. Fungicides 

may alter and impact soil microbial communities, thus there is a potential to impact herbicide 

degradation, and change herbicide efficacy and environmental fate characteristics. ARS 

researchers at the Southeast Watershed Research Laboratory in Tifton, GA evaluated potential 

impacts of four fungicides widely used by peanut growers on the soil persistence of a 

commonly used herbicide (metolochlor). One of the fungicides was found to double the time 

the herbicide persisted in soil. This information is of considerable value to peanut growers and 

other farmers in the region who use these chemicals. Modified farming practices, such as 

reducing herbicide application rates, may need to be considered where the fungicide and 

herbicide are used in combination. 

Speeding up soil quality recovery in sandy soils under dryland production. Since the 

1940s, much of the land in the Southern High Plains region has been planted solely to cotton 

using conventional tillage practices, resulting in declining soil quality. To sustain future 

agricultural activities in this area, conservation practices such as minimum tillage and cotton 

rotations with sorghum are being implemented to reduce erosion and restore soil quality in 

dryland production. However, it often takes many years before improvements can be seen. 

ARS scientists at Lubbock, TX found that introducing a rotation of cotton with high biomass 

crops, such as forage sorghum and a winter rye cover crop, produced increases in microbial 

biomass carbon and nitrogen, and the activities of enzymes important for nutrient cycling, in 

as little as three years. It took over five years to show improvements under rotations of cotton 

and grain sorghum compared to cotton monoculture. This is new information that growers and 

researchers can consider when identifying cropping systems that will result in improved soil 

quality and functioning. 

Physical/chemical fractionation procedures developed for soil organic matter

characterization. The complex nature of soil organic matter (SOM) was more completely 

characterized using innovative physical/chemical fractionation procedures in combination 
with state-of-the-art spectroscopic techniques. ARS scientists in Ames, IA devised an 

innovative, integrated SOM fractionation/characterization procedure that permitted sequential 

isolation of SOM fractions obtained using physical or chemical separation of the same soil 

sample. Multiple laboratory analyses were used to characterize and compare elemental and 

chemical composition of several physically- or chemically-defined SOM fractions with whole 

SOM. This method is being used to detect subtle differences in carbon pools and nutrient 

cycling due to soil and crop management, such as tillage, crop rotation, cover crops, and 

bioenergy feedstock production. 

Biochar can be used to increase carbon storage and improve soil quality in Midwestern 

fields. Biochar is a form of charcoal produced while making renewable biofuels through the 

process of pyrolysis. ARS scientists in Ames, IA, conducted laboratory and field studies to 

determine how biochar affected several soil biological, chemical, and physical properties in a 

typical agricultural soil. The laboratory study showed that applying biochar decreased soil 

compaction, increased soil acidification, and increased the capacity of soil to hold water and 

plant nutrients compared to soils that did not receive biochar. Applying biochar increased 

total nitrogen by as much as 7%, organic carbon by as much as up to 69%, and the quantity of 

several other plant nutrients compared to the unamended soil. These results are important 

because pyrolysis produces a co-product that can be used to increase soil carbon storage and 

improve other soil properties and processes (i.e., soil quality). 

Improved productivity of sandy coastal soils. Because the southeastern U.S. Coastal Plain 

is hot and wet, its weathered sandy soils have low organic carbon contents and poor 

productivity. A study was conducted to test the potential benefits of soil additions of biochar. 

ARS researchers at Florence, SC, added C to a coastal soil in the form of non-activated pecan 

biochar and, as a comparison with a more conventional carbon source, finely ground 

switchgrass. Both biochar and switchgrass additions decreased soil compaction. Switchgrass 

additions, however, also increased the water holding capacity of the soil while the biochar 

additions did not. These improvements enhance the quality of these degraded and weathered 

sandy soils and help sequester carbon. 

Cost of nutrient losses in furrow irrigation runoff. Nutrients in furrow irrigation runoff are 

a lost resource. ARS researchers at Kimberly, ID, measured the amount of phosphorus, 

inorganic nitrogen, and potassium lost in runoff from furrow-irrigated fields that were 

fertilized either conventionally or with manure. Most of the nutrient loss was phosphorus, 

and most of the phosphorus loss was associated with sediment. Less than 3% of the applied 

nitrogen was lost (2.7% of total inorganic N applied to fertilizer plots, 1.5% of total N applied 

on manure plots). About one third of the phosphorus applied with the manure was lost with 

runoff during the two-year study (84 lb P/acre lost out of 219 lb P/acre applied in two years). 

No phosphorus was applied to the fertilizer or control treatments, which had losses of 33 to 48 

lb P/acre /year. The cost to replace nitrate, ammonia, potassium and phosphorus from control 

plots averaged $35/acre/year; and $40/acre/year for fertilizer and manure treatments. This 

research underscores the need for management practices to reduce nutrient losses from 

furrow-irrigated soils. 
Corn yield increased by applying fertilizer with strip tillage. Strip tillage is a conservation 

practice that can incorporate fertilizer into the soil while leaving much of the surface 

undisturbed. This tillage practice can potentially increase corn yield by applying fertilizer 

directly beneath the corn row. ARS researchers at Kimberly, ID, determined that applying 

nitrogen and phosphorus fertilizer with strip tillage increased corn yield on eroded soils 12% 

compared to broadcast fertilizer application, and 26% compared to surface banding with the 

planter. Reduced tillage costs and potential increased corn yield with strip tillage could 

increase the economic productivity of eroded land in the Pacific Northwest.