Project Number: 5402-11000-007-00
Project Type: Appropriated

Start Date: Nov 17, 2004
End Date: Nov 16, 2009

Objective:
1. Determine effects of cropland and rangeland management practices in the Great Plains on agricultural greenhouse gas intensity (GHGI) (net emissions of CO2, CH4, and N2O per unit of agricultural commodity produced) by: a)quantifying GHGI in field plots under different management practices and, b) applying data and information to project impacts of different management practices on GHGI, via process-based simulation models. 2. Determine land management and climate effects on the size and dynamics of soil organic carbon (SOC) and soil inorganic carbon (SIC) pools by: a) developing methods to measure soil C pools and SOC sequestration. b) measuring SOC pools for long-term continuous no-till with intensive crop management practices under field conditions. c) application of computer models to assess changes in soil carbon stocks resulting from land use and land use change. NEW: Develop network of several ARS locations for GRACEnet (Greenhouse gas Reductions through Agricultural Carbon Enhancement network). These locations will be determined in the near future in consultation with NPS. Lead and coordinate the national ARS project, GRACEnet, a multi-location project to study greenhouse gases (GHGs) in agricultural systems. Coordinate and analyze data from multi-location field studies following standardized protocols to compare net GHG emissions (carbon dioxide, nitrous oxide, methane), carbon (C) sequestration, and broad environmental benefits under different management systems that: typify existing production practices for significant agricultural systems in different parts of the country, maximize C sequestration, minimize net GHG emissions, and meet sustainable production and broad environmental benefit goals (including C sequestration, net GHG emissions, water/soil quality, etc.). Data from multi-location field studies following standardized protocols will be analyzed to compare net GHG emission (Carbon dioxide, nitrous oxide, methane) carbon (C) sequestration, and broad environmental benefits under different management systems that: typify existing production practices for significant agricultural systems in different parts of the country, maximize C sequestration, minimize net GHG emissions, and meet sustainable production and broad environmental benefit goals (including C sequestration, net GHG emissions, water/soil quality, etc). Analyze results from GRACEnet, in cooperation with network participants to: identify practices that balance production and environmental goals related to C sequestration and GHG emissions; identifying ways to produce biofuels crops while meeting environmental goals; develop accurate and easy-to-use models to predict C sequestration and GHG emissions in repsonse to on-farm management decisions; determine how to scale plot estimates of C sequestration and GHG emissions to regional and national scales; use remote imaging to estimate C stocks; and develop fast, accurate, and inexpensive ways to measure or estimate soil C and GHG fluxes.

Approach:
Objective 1 a. Greenhouse gas intensity will be quantified in field plots under different management practices to determine the effect of tillage, fertilization, irrigation and crop rotations in irrigated and dryland conditions. The irrigated cropping system incorporates trace gas exchange, soil C, and crop production measurements within an ongoing field plot study that was initiated in 1999. A study to quantify net GWP within an established dryland agricultural management project will be conducted within a project that was established in 1985 in northeastern Colorado. Objective 1 b. Field and laboratory studies will be conducted in or using soils from plots described in 1 a. to identify mechanisms by which soil biological, chemical, and physical processes affect production, emission, and consumption of NO, N2O, CH4, and CO2 in soils. The impact of soil water content and bulk density on trace gas fluxes will be evaluated from field measurements after several years of observations. We will also conduct short-term studies under more controlled conditions, either in field or using intact soil cores. Established procedures which employ highly 15N-enriched fertilizer or 13C-labeled CH4 will be used to determine the effect of soil WFPS on gas exchange. Objective 1 c. Data and information from collected for objectives 1 a and 1 b will be used for DAYCENT model verification to project impacts of different management practices on GHGI, via process-based simulation models. Crop production and ancillary data from the above studies will be used to verify DAYCENT output for irrigated systems. The model will then be used to estimate GHGI for various management scenarios for irrigated systems in the Great Plains. Objective 2a. Soil C pools and SOC sequestration will be determined using new technology such as near- or mid-Infrared diffuse reflectance spectroscopy to determine soil C pool concentrations to provide accurate, yet rapid soil C pool information. Molecular beam mass spectrometry (MBMS) will be used to determine soil C pool concentrations to provide accurate, yet rapid soil C pool information and soil C age. Objective 2b. The impact of agricultural management on soil C and N cycles in long-term continuous no-till with intensive crop management practices under rainfed conditions will be determined in analysis of soils from long-term field experiments. On-farm sites will be selected near and around Richmond, VA that include long-term continuous no-till to compare with long-term conventional tillage sites. This study will allow an evaluation of the change in soil water stable aggregates, water infiltration and retention, and SOC that have occurred following at least 10 yr. Objective 2c. The previously developed databases and those currently being collected will be used to contribute to the calibration and validation of a newly revised Windows-friendly version of the CQESTR computer model for on-farm and farm advisor use and for potential expansion to allow it to begin to address regional estimates of soil C sequestration and changes in C stocks. NEW: Coord. the activities of the network with several ARS locations for GRACEnet