Location: Natural Resource Management Research2012 Annual Report
1a. Objectives (from AD-416):
OBJECTIVE 1: Develop management strategies to decrease net greenhouse gas emissions from cold, semiarid agroecosystems, as a contributor to the ARS GRACEnet project. OBJECTIVE 2: Develop soil management guidelines to improve soil biophysical properties needed for sustainable production.
1b. Approach (from AD-416):
Concurrent trends of increased demand for agricultural products, increasingly scarce nonrenewable resources, and accelerating climate change have underscored the need for new and innovative agroecosystems that are resilient, highly productive, effectively utilize renewable resources, and minimize damage to the environment. Determining the relative sustainability of new and innovative agroecosystems requires a detailed understanding of management effects on emerging ecosystem services. Given this context, the goal of this project is to improve understanding of management impacts on greenhouse gas mitigation, carbon storage, and soil biological function. Over a time period of approximately five years, research activities will 1) develop management strategies to decrease net greenhouse gas emissions from cold, semiarid agroecosystems (Objective 1), and develop soil management guidelines to improve soil biophysical properties needed for sustainable production (Objective 2). Approaches to conduct these research activities will include field, laboratory, and greenhouse experiments. Anticipated products from this research include peer-reviewed publications, popular press articles, and web pages. Collectively, these products will serve a broad range of clientele (e.g., agricultural producers, personnel from public and private sector organizations, and scientists), and will contribute to an overall outcome of increased understanding of agroecosystem effects on emerging ecosystem services, with the intent of improving agricultural sustainability.
3. Progress Report:
Cropping practices in a long-term (18 yr) dryland cropping systems experiment were updated to account for emerging trends in northern Plains crop production. Specifically, millet and safflower were replaced with corn and soybean in applicable rotations. Additionally, a 7-way cover crop mixture replaced a rye cover crop treatment in a three-year rotation. Spring soil samples were collected to a 1.5 m depth in a long-term (18 yr) dryland cropping systems experiment prior to implementation of new cropping practices. Soil samples were collected to 90 cm within alfalfa and pasture treatments along with surface (0-15 cm) samples from a continuous spring wheat site. The samples were divided into 0-15, 15-30, 30-60, and 60-90 cm depth increments to correspond with sampling depths for gas wells.
1. Greenhouse gas emissions from thawing soils. Effects of freezing and thawing on greenhouse gas emissions from soil are poorly understood. Researchers at the USDA-ARS Northern Great Plains Research Laboratory found similar gas flux responses to temperature changes when soil thawed. Similar patterns across soil depths for nitrous oxide and carbon dioxide flux suggest modeling efforts could use temperature and microsite soil properties to estimate soil greenhouse gas emissions. Findings in this study can aid in the development of management practices to retain carbon and nitrogen in cropland and rangeland as soils warm in northern latitudes.
2. Crop rotation affects yields. Selecting the right crop to plant is one of the most important management decisions made by farmers over the course a growing season. At the USDA-ARS Northern Great Plains Research Laboratory, researchers found spring wheat yield was increased 11% when the previous year’s crop was dry pea. Conversely, corn was found to decrease spring wheat yield up to 10%. Depletion of soil water by corn was found to be the overriding factor contributing to decreased spring wheat yield. To ensure optimum crop yields and reduce production risks, farmers in the northern Plains must be strategic with crop selection by taking into consideration inherent differences in crop water use and the availability of soil water before and during the growing season.
3. Major greenhouse gas book published. Concurrent efforts to mitigate agricultural contributions to climate change while adapting to its projected consequences will be essential to ensure long-term sustainability and food security in the U.S. To facilitate successful responses to climate change, USDA-ARS scientists involved in GRACEnet (Greenhouse Gas through Agricultural Carbon Enhancement Network) published a book documenting recent research accomplishments addressing strategies to mitigate and adapt to climate change. The book, entitled Managing Agricultural Greenhouse Gases: Coordinated Agricultural Research through GRACEnet to Address our Changing Climate, includes regional syntheses of soil organic carbon and greenhouse gas (GHG) dynamics for broad portfolio of agricultural land uses, as well as additional chapters central to GRACEnet activities (e.g., modeling, method development, economic outcomes of GHG mitigation options, adaptation research, and international collaboration). The book will support ARS’ goal of providing knowledge and information on soil carbon sequestration, GHG emissions, and environmental benefits to better implement scientifically-based agricultural management practices from field to national policy scales.
Wick, A.F., Phillips, B.L., Liebig, M.A., West, M.S., Daniels, W. 2012. Linkages between soil micro-site properties and CO2 and N2O emissions during a simulated thaw for a northern prairie Mollisol. Soil Biology and Biochemistry. 50:118-125.