Approximately 6% of all greenhouse gas (GHG) emissions originating in the United States (U.S.) come from agricultural activities.1 These gases are in the form of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). However, by employing proper management techniques, agricultural lands can both sequester carbon and reduce CO2, CH4, and N2O emissions, thereby reducing their GHG footprint. Cap-and-trade climate change legislation, currently under discussion in the legislative and executive branches, may have broad and long-term implications for the agricultural sector. In order to determine the role of agriculture in GHG emissions and capture, a full life cycle accounting of GHG sources and sinks is needed. The American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and Soil Science Society of America (SSSA) have examined the evidence for GHG emissions and sequestration typical of agricultural systems in six U.S. regions (Figure 1): â?¢ Northeast â?¢ Southeast â?¢ Corn Belt â?¢ Northern Great Plains â?¢ Pacific â?¢ Southern Great Plains This report summarizes current knowledge of GHG emissions and capture as influenced by cropping system, tillage management, and nutrient source. Additionally, topics requiring further research have been identified.
