Nitrous Oxide Emissions from Cropland Soils with Different Management Regimes in Manitoba, Canada
Nitrous Oxide Emissions from Cropland Soils with Different Management Regimes in Manitoba, Canada
Previously Published Material: Preliminary results from the 2013 growing season for one of our study sites were presented in a poster titled "Nitrous oxide flux from a clay loam under mature no-till and variable rate N fertilizer management in western Manitoba" at the 57th Annual Manitoba Soil Science Society Conference held in Winnipeg in February 2014.
Abstract ID#: 35609
English Abstract:
Globally, the agricultural sector is the largest anthropogenic source of nitrous oxide (N2O) to the atmosphere, the majority of which can be attributed to biogeochemical transformations of nitrogen (N) added to cropland soils. The Canadian Tier II methodology used for national GHG inventory reporting implicates the application of synthetic N fertilizer to cropland soils as the largest anthropogenic source of N2O nationally and indicates that emissions from this source have increased by more than 70% between 1990 and 2012. As synthetic N fertilizer application is the main source of anthropogenic N2O globally and nationally, efforts to use fertilizer more efficiently have a significant potential to reduce overall emissions from this source. The objectives of this study are to identify the relative influence of environment, management and climate on soil N2O emissions and to measure the emission per unit production for a range of cropping systems in the region. In ongoing studies beginning in 2012, soil N2O fluxes have been measured using the static-chamber technique in various agroecosystems in southern Manitoba. The farm characteristics vary from integrated crop-livestock operations with beef cattle manure and compost applied to soil as nutrient amendments, to a mature no-till cropland with variable rate N fertilizer management. Surface soil textures are similar at the majority of the sites but the organic C content and inorganic N availability of surface soils vary considerably. Soil temperature and moisture content were monitored during the measurement periods and related to the timing and magnitude of N2O emissions. These measurements of soil N2O emissions from cropland in the subhumid eastern Canadian Prairies may help to refine and revise estimates for regional inventories, particularly with regards to coefficients related to hydrology, soil texture, climate, and soil management activities. Current results from the research will be shared and discussed.