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FY2011 Annual Report 

National Program 212 – Climate Change, Soils, and Emissions

Introduction

National Program (NP) 212, Climate Change, Soils and Emissions Research 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 result 

from 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 in precipitation and temperature patterns, and increased 

atmospheric carbon dioxide (CO2) concentration. The impacts of climate change create 

challenges to agriculture and its soil resources, 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. 

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 data bases will enhance synthesis and integration analyses and expand 

research opportunities.

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), 
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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.

Selected Accomplishments

Herbicide volatilization exceeds herbicide runoff losses. Surface runoff was thought to 

be the major off-site transport mechanism for herbicide. However, until recently no field 

investigations monitored both surface runoff and turbulent volatilization fluxes 

simultaneously. An 8-year, field-scale experiment in Beltsville, Maryland was conducted 

where herbicide (atrazine and metolachlor) volatilization and surface runoff losses were 

simultaneously monitored and evaluated. Results demonstrate that regardless of weather 

conditions, volatilization losses consistently exceeded surface runoff losses. Surprisingly, 

herbicide volatilization losses were up to 25 times larger than herbicide surface runoff 

losses. The research will affect USDA and USEPA policy with regard to herbicide 

behavior and the data will be used to develop or improve pesticide behavior models.

Assessed the benefits of new manure application methods. In a well managed animal 

production system, manure nutrients are returned to the soil where they are used to 

produce feed crops for the animals. During this cycle though, losses occur in the form of 

gaseous emissions, leaching to groundwater, and runoff in surface water. ARS scientists 

at University Park, PA, with collaboration from the Pennsylvania State University 

verified a farm model to appropriately represent several manure application methods and 

then used the model to assess and compare their long term environmental and economic 

impacts on farms. Use of a shallow disk injection device for applying manure below the 

soil surface generally provided the lowest nutrient losses without substantially reducing 

farm profit. This new information is guiding animal producers and policymakers in the 

Chesapeake Bay region toward manure application technologies that simultaneously 

reduce environmental impact and maintain or improve farm profit.

New mathematical model accurately predicts pest control and emissions of soil 

fumigants to the atmosphere. The use of soil fumigants is an important component of 

U.S. agriculture but fumigants have the potential to pollute the atmosphere; new methods 

are needed to ensure crop protection while minimizing atmospheric emissions. 

Experiments conducted at U.S. Salinity Laboratory demonstrate that a predictive model 

could be used to simultaneously estimate fumigant emissions and the control of plant pest 

organisms in field soil. The results show that the model accurately predicted both 

emissions and pest control and provides a new approach to optimize fumigant 

applications that ensure crop protection while minimizing atmospheric emissions. This 

methodology could be very valuable to growers in need of tools to manage soil fumigants 

and plant pests. 

Cotton gin particulate matter emissions measurements. The cotton ginning industry 

was turned upside down in 2006 when EPA mandated that the amount of PM2.5 

emissions be reduced by nearly half. The offending PM2.5 emissions are particles less 
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than 1/30th the thickness of a human hair, basically a very fine dust produced during the 

ginning process. With no real emissions data on this agricultural operation, state 

regulatory agencies have been scrambling to determine levels of these small particles 

other than best-guess, which could lead to overestimation and an unnecessary burden 

imposed on the industry, not to mention possible fines. In a collaborative effort, ARS 

researchers in Mesilla Park, NM; Stoneville, MS; and Lubbock, TX, and Oklahoma State 

University researchers in Stillwater, OK, are in the third year of a four-year industrysupported project to measure emissions from gins across the country. Earlier this year 

when California action agencies had to show EPA progress on implementing a regulatory 

program, all involved with the gin emissions study were able to agree upon and compile 

scientifically supported preliminary PM2.5 emissions information from four of the total 

seven gins scheduled to be sampled for the project. This information met the immediate 

needs of the California regulators, and is a model of how scientist and agriculture 

working with state and federal regulators can collaborate to provide scientifically-sound 

emissions data. At the end of the day, regulatory agencies were provided with data that 

accurately represents PM2.5 emissions from US cotton gins, thus assuring a sound basis 

for setting and enforcing regulations. 

Component 2: Develop Knowledge and Technologies for Reducing Atmospheric

Greenhouse Gas Concentrations through Management of Agricultural Emissions 

and Carbon Sequestration

Agriculture GHG emissions to the atmosphere are among the documented anthropogenic 

factors driving climate change. 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.

Selected Accomplishments

Nitrogen fertilizer source influences nitrous oxide emissions from strip-till corn. 

Nitrous oxide (N2O) is a potent greenhouse gas emitted when inorganic N fertilizers are 

applied to agricultural crops. ARS Scientists in Fort Collins, CO, compared N2O 

emissions from alternative N fertilizer sources to commonly used granular urea and liquid 

urea-ammonium nitrate (UAN) fertilizers in an irrigated, strip-till corn system. Some 

alternative N sources reduced growing season N2O emissions up to 70% compared to 

urea, and 49% compared to UAN. Cropping system managers and policy makers can now

consider selection of N fertilizer source as a mitigation practice for reducing N2O 

emissions and global warming potential for the semi-arid western U.S.

Web-based Book of GRACEnet Soil Carbon Sampling Protocols. The Greenhouse 

Gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) is a 

coordinated national effort that was established during 2005 by the USDA - Agricultural 

Research Service. As part of this effort guidelines were established to enable research 

collaborations and common sampling and sample collection protocols across many 

locations and within different agro-ecosystems to assess the soil carbon consequences of 
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agricultural management systems at local, regional, and national scale. The use of 

common management scenarios, consistent sampling protocols, and detailed record 

keeping facilitates cross-location and cross-regional comparisons and ensures quality 

control even with location-specific soils, crops and conditions. The chapters in this book 

were prepared by leading ARS scientists. It is located on the ARS GRACEnet website < 

http://www.ars.usda.gov/research/GRACEnet > and is freely available to anyone visiting 

the website. Copies on CD have also been shared with the 31 countries of the Global 

Research Alliance (GRA) on Agricultural Greenhouse Gases, who are considering the 

use of these protocols worldwide. The availability of these protocols enable comparison 

of soil carbon across space and time, thus enabling collaboration on the development of 

management practices to help mitigate atmospheric CO2 emissions from world-wide 

agriculture systems.

U.S. Agriculture and Forestry Greenhouse Gas Inventory published by USDA.

Interest in climate change and efforts to reduce the environmental impacts of agricultural 

production systems highlight the need for more accurate methods to quantify greenhouse 

gas emissions from the US agricultural sector. The recently published U.S. Agriculture 

and Forestry Greenhouse Gas Inventory 1990-2008 feature state of the art methods to 

calculate emissions and their associated uncertainty ranges. The report partitions 

emissions spatially and by source category so policy makers can identify where 

mitigation efforts should be targeted. Results from this inventory are also included in the 

annual Inventory of US Greenhouse Gas Emissions and Sinks published by EPA and 

reported to The United Nations Framework Convention on Climate Change (UNFCCC). 

The website hosting the report has received several hundred visits per month.

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.

Selected Accomplishments

Carbon dioxide eliminates desiccation in warmed semi-arid rangelands. Climate 

change is expected to bring warmer, desiccating conditions to many world rangelands. 

However, many analyses have not considered the direct effect of rising CO2, which ARS 

scientists hypothesized would positively improve plant water use efficiency, thereby offsetting the negative effects of warming-induced desiccation. ARS scientists in Cheyenne, 

WY, Fort Collins, CO, and Maricopa, AZ, plus collaborators from the University of 

Wyoming created an experiment with higher CO2 and slightly warmer temperature 
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conditions expected to occur during the second half of this century. They discovered that 

combined elevated CO2 and warmer temperatures favored growth of warm-season, 

perennial grasses, and that the additional CO2 completely reversed the desiccating effects 

of the warmer temperature in a typical native semi-arid prairie environment. These results 

are helping climate change scientists make better predictions about how rising CO2 will 

affect the responses of rangelands to climate change, and are being used to develop 

climate change adaptive management strategies for ranchers and public land managers.

Physiological basis for differential productivity in switchgrass ecotypes. Switchgrass, 

a native grass in the U.S. has gained large popularity as a biomass crop for bioenergy. It 

is adapted to a wide range of environments; however, its productivity declines the further 

north it is grown within its native range. ARS Researchers at Morris, MN, discovered that 

when moved from near ideal to low growth temperatures, varieties of switchgrass 

adapted to different parts of the U.S. did not acclimate photosynthetically but instead they 

adjusted the way they made and used sugars such that some grew better than others at 

cooler than ideal temperatures. Notably, a southern variety was found to produce more 

biomass than northern varieties, even at low temperatures. This was partly because it 

made more sugar for growth (sucrose) than storage (starch) than other varieties did. The 

information greatly helps other scientists, especially plant geneticists, developing more 

productive switchgrass varieties for bioenergy.

Effects of warmer air temperatures on crop growth, development, ecophysiology 

and yield. To determine how increasing air temperatures may affect future crop yields, 

ARS scientists from the U.S. Arid-Land Agricultural Research Center, Maricopa, AZ and 

the University of Arizona used infrared heaters and varied planting dates to expose wheat 

crops to an unusually wide range of temperatures. The effects of higher air temperature 

on wheat yield varied due to interacting effects of planting date, risk of frost, and the 

response of crop photosynthesis, water use and duration of wheat crops. For two planting 

dates, warming protected the developing wheat grain heads from frost damage and led to 

good yields, while lower ambient air temperature plots produced no grain. The results 

indicate that increasing air temperatures using current management and/or cultivars will

likely decrease wheat yields in irrigated systems of Arizona and California. However, if 

warming is sufficient to reduce the risk of frost, growers might plant wheat earlier, thus 

extending the wheat growing season and either stabilizing or increasing wheat yields. 

This information provides insights needed to develop adaptation strategies for adapting 

agricultural production to changing climate conditions.

Corn water use efficiency increases under elevated CO2. Water availability for 

agriculture is expected to decline as atmospheric CO2 increases in the future. Thus, it is 

important to understand how plants grown under elevated CO2 will respond to water 

stress. ARS scientists in the Crop Systems and Global Change Laboratory, Beltsville, 

MD, investigated the relationship between plant growth and water use for a corn crop in 

soilbins housed in sun-lit growth chambers under two CO2 concentrations. Soil water 

contents observed under elevated CO2 were higher than those grown under ambient CO2 

concentrations even though less irrigation water was applied. The corn grown under 

elevated CO2 used up to 20% less water than corn grown under ambient CO2 levels. This 
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information provides information for researchers, growers and agricultural policy makers 

to devise strategies for adapting agricultural production to changing climate conditions.

Improved nitrogen management tool released online. Nitrogen losses from 

agricultural systems impact soil, water, and air quality. There is a need for new tools that 

can help assess reactive nitrogen losses from agricultural systems. New USDA-ARS tools 

such as the Nitrogen Trading Tool, Nitrogen Index 4.3, and NLEAP-GIS 4.2 were 

calibrated and validated, and were released in December 2010 via a new ARS webpage 

(http://www.ars.usda.gov/npa/spnr/nitrogentools). These tools have been downloaded 

hundreds of times and are being used by international agencies, universities, and national 

and international peers to assess the effects of management practices on nitrogen losses in 

order to reduce these losses to the environment. .

Environmental impacts of biofuel feedstock production systems. The Energy 

Independence and Security Act of 2007 mandates increased production of energy from 

alternate fuel sources such as biomass. ARS Researchers in Fort Collins, CO, used field 

data from biofuel feedstock plots in the central and eastern US to verify the ability of a 

commonly used computer model called DAYCENT to represent the ethanol yields and 

greenhouse gas emissions for different crops. They then used the model to quantify yields 

and greenhouse gas emissions for lands currently used for corn ethanol production and to 

project yields and emissions if this land was converted to cellulosic ethanol production 

using perennial crops. Results suggest that if land currently used for corn ethanol 

production were converted to perennial crops, ethanol production could increase from 7 

to 12 billion gallons while greenhouse gas emissions from soil would decrease by 

approximately 400%. These finding are critical for efficient energy production from plant 

feedstocks for the United States.

Soil Microbial Responses to Elevated Carbon Dioxide and Ozone in a WheatSoybean Cropping System. Climate change factors such as rising atmospheric carbon 

dioxide (CO2) and ozone can exert significant impacts on crop growth, but how the soil 

microbes in agricultural systems respond to these factors remains largely unexplored. 

Using a long-term field study conducted in a no-till wheat-soybean rotation system with

open-top chambers, ARS researchers in Raleigh, NC showed that elevated CO2 

stimulated plant biomass production and ozone lowered plant biomass production, but 

only elevated CO2 significantly affected soil microbial biomass, respiration and 

community composition. Enhanced microbial biomass and activity from elevated CO2 

coincided with increased soil nitrogen availability likely due to stimulation of soybean 

nitrogen-fixation under elevated CO2. These results highlight the need to consider the 

interactive effects of carbon and nitrogen availability on microbial activity when 

projecting soil carbon balance under future CO2 scenarios. The addition of nitrogen to 

agricultural systems through fertilizers or legume crops may stimulate microbial 

decomposition processes and limit carbon sequestration potential. These findings enhance 

our ability to predict and manage soil carbon sequestration under changing climate 

conditions.

Component 4: Maintaining and Enhancing Soil Resources
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Soil productivity must be enhanced to meet increasing global food, feed, fiber, and fuel 

demands. 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.

Selected Accomplishments

Conservation-based biomass feedstock harvest recommendations. Crop residues are a 

potential renewable bioenergy feedstock that can produce power, heat and transportation 

fuels. Crop residues refer to the non-food portion of a crop that remains after grain 

harvest that protects soil from erosion and builds soil organic matter. Guidelines or 

recommendations are needed when deciding where, if, and how much residue needs to 

remain on the land and how much may be harvested. ARS Researchers at Morris, MN, 

developed recommendations for conservation-based biomass feedstock harvest, which 

were used to write university and Natural Resources Conservation Service (NRCS) 

factsheets, and were presented at workshops and field days. These guidelines provide 

decision tools to producers, consultants, extension and NRCS, and industry for 

determining where, if, and how much crop residue can be harvested. Furthermore, 

research-based recommendations were developed for safeguarding soil productivity if 

residue is harvested so that soils can indefinitely supply food, feed, fiber and fuel.

Greenhouse method to produce sweet corn seedlings well colonized by arbuscular 

mycorrhizal fungi for organic farming. Growing sweet corn seedlings in greenhouses 

and transplanting them to the field earlier during the growing season rather than directly 

sowing seeds in the field, helps farmers take advantage of higher prices paid for early 

season produce. The greenhouse seedling production also provides an opportunity to 

inoculate seedlings with arbuscular mycorrhizal (AM) fungi, beneficial soil fungi that 

colonize roots and enhance crop nutrient uptake, disease resistance, and drought 

resistance. Unfortunately, the two-week greenhouse growth period can be too short for 

AM fungi to colonize roots unless optimal conditions exist, thus potentially wasting 

money and time on inoculation. ARS researchers at Wyndmoor, PA, in cooperation with 

The Rodale Institute tested different greenhouse nutrient and potting media regimes as a 

means of accelerating AM fungi colonization of sweet corn seedling roots. A mix of preincubation, inoculated potting media containing compost was used to stimulate 

germination of AM fungi prior to sowing seeds in the greenhouse. A 1:3 mixture of AM 

inoculum and the potting media was then shown to produce extensive colonization of 

sweet corn roots within the two-week greenhouse growth period. These results provide a 

strategy to enable organic and non-organic farmers to utilize AM fungus inoculum for 

sweet corn production, thus increasing the likelihood of successful sweet corn yields, and 

increased economic return.

Future Activities
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Research conducted for the ARS NP212 Climate Change, Soils and Air Emissions 

program will continue during coming year with an increased emphasis on synthesis of 

results and preparation of technology transfer mechanisms. The program will begin an 

assessment of its most recent five years of research and begin planning the next five year 

research agenda. A report will be produced summarizing program accomplishments 

focused on objectives set forth by the 2009-2013 Action Plan. This report will be 

reviewed by a panel of non-ARS employees as per ARS Office of Scientific Quality 

Review (OSQR) protocols. The program summary report will be posted on-line. 

ARS personnel of the NP212 program are also contributing to a variety of activities of 

USDA, national and international interest: 

• The National Climate Assessment,

• Greenhouse Gas Mitigation Options guidelines for agriculture,

• The National Earth Observations Strategy,

• Development of concepts and algorithms for future earth resource satellites,

• The Global Research Alliance on Agricultural Greenhouse Gases (GRA),

(http://www.globalresearchalliance.org/)

• Collaboration with EPA on analysis of data collected for the National Air 

Emissions Monitoring Study (NAEMS)

Substantial progress was made on data management systems for GRACEnet and REAP 

during 2011. This effort is continuing. 

Research collaborations are being planned with USDA-APHIS, USDA-NRCS, NASA, 

NOAA, Department of Energy, and Department of Interior among others. There is 

increasing interest in ARS climate change mitigation and adaptation research, air quality 

research data and ARS simulation models by domestic and international partners.