HR: 0800h
AN: B31A-0068    [Abstracts]
TI: Diurnal, Seasonal and Inter-annual Variations of N2O Fluxes from Perennial Vineyard Soils in California, USA.
AU: * Suddick, E C
EM: ecsuddick@ucdavis.edu
AF: University of California, Davis, Department of Viticulture and Enology Wickson Hall One Shields Avenue, Davis, CA 95616, United States
AU: Carlisle, E A
EM: ecarlisle@ucdavis.edu
AF: University of California, Davis, Department of Viticulture and Enology Wickson Hall One Shields Avenue, Davis, CA 95616, United States
AU: Spencer, R G
EM: rgspencer@ucdavis.edu
AF: University of California, Davis, Department of Land Air and Water Resources One Shields Avenue, Davis, CA 95616, United States
AU: Smart, D R
EM: drsmart@ucdavis.edu
AF: University of California, Davis, Department of Viticulture and Enology Wickson Hall One Shields Avenue, Davis, CA 95616, United States
AB: The USA emits 1562 million metric tons of carbon equivalents a year, whereby this value is projected to rise by an estimated 14 % in 2012. California is the 12th major global emitter of greenhouse gases, emitting approximately 500 million metric tons of carbon equivalents a year. 84 % of greenhouse gas emissions are from CO2, 7 % and 6 % from N2O and CH4 respectively and approximately 8 % of these emissions are derived from agricultural activities. The concentration of nitrous oxide (N2O) within the atmosphere has been increasing at a rate of approximately 0.27 % per year and has mainly been attributed to agricultural practices such as land-use changes, biomass burning, nitrogen fertilization, livestock and manure management. Agriculture related activities generate from 6 to 35 Tg N2O-N per year, or about 60 to 70 % of global production. The primary biogenic sources of N2O are from terrestrial soils, which are thought to be a major source of N2O to the atmosphere and mainly involve the microbial nitrogen transformations brought about by nitrification and denitrification. The aim of this study was to quantify the seasonal and inter-annual variability of N2O emissions and nitrogen cycling from a conventionally tilled wine grape vineyard in Napa, California during a two year closed static chamber study and to also investigate the diurnal N2O flux pattern and effects of fertilization management practices on emissions within a table grape vineyard in Delano, California. Preliminary data shows that the annual N2O fluxes were influenced by soil properties, management practices and weather such as precipitation events where increases in N2O emissions were observed after irrigation or fertilization practices and immediately following rainfall. Vineyard floor and vine management will be discussed in terms of the significance management practices have upon the release of N2O emissions from vineyard soils where the high water and nitrogen fertilizer usage within these perennial cropping systems may be significant sources of N2O production. The data obtained from this study will be utilized to contribute to and quantify regional greenhouse gas budgets which may not have been included in previous budgets in relation to policy implications and potential mitigation strategies on a regional and global scale.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0469 Nitrogen cycling
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
DE: 0478 Pollution: urban, regional and global (0345, 4251)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting