Greenhouse Gas Contributions and Mitigation Potential of Agriculture Management in the Dry South and West - 300 Ecoregion. (4351)
Authors:
D.A. Martens* - USDA-ARS, Tucson, AZ J.E.T. McLain - USDA-ARS, Tucson, AZ W. Emmerich - USDA-ARS, Tucson, AZ T.N. Johnsen Jr. - USDA-ARS, Tucson, AZ
Abstract:
The southwest United States has abundant sunshine and warm temperatures to support agriculture, yet the impacts of agriculture on mitigation of greenhouse gas emissions (GGE) or sequestration of atmospheric C in soils are not fully realized. Across Texas, reduced tillage (RT) has been found to increase soil C content 38.4 g C m-2 yr-1 compared with more intensive tillage with C retention rates higher under cooler MAT and increased cropping intensity. Conversion of tilled row crops to the Conservation Reserve Program or pastures has potential to sequester from 500 to 1100 g C m-2 yr-1, although, the rates of GGE accompanying the higher C retention rates from RT or pasture systems have not been documented. Due to the limited information on soil C content with grazing management, no C sequestration estimates can be made for grazing management. Irrigated agriculture in Idaho with RT management can sequester 1-4 g C m-2 yr-1 compared with tillage systems, while tilled irrigated production in Idaho will result in a loss C compared to nonirrigated native vegetation. Despite
approximately 75% of the region's soils being classified as calcic, the potential of SIC sequestration has experienced limited research. Research is needed to document agricultural sustainability and increased potential mitigation of atmospheric C with RT-irrigation practices.
Speaker Information: Dean Martens, USDA-ARS, Tucson, AZ, Southwest Watershed Research Center 2000 E. Allen Road, Tucson, AZ 85719; Phone: 520-670-6380; E-mail: [email protected]
Session Information: Monday, November 1, 2004, 1:00 PM-3:00 PM Presentation Start: 1:00 PM (Poster Board Number: 2620)
Keywords: carbon sequestration; trace gases; carbon dioxide; nitrous oxide