Nitrous oxide emissions from grazing animal excreta in pastures under dry climate

Animal excreta is an important contributor to agricultural nitrous oxide (N2O) emissions – a potent greenhouse gas. Soil N2O emissions are episodic in nature and commonly subjected to drastic inter-annual and spatial variation. Thus, location-specific studies are much needed to further our knowledge on global terrestrial N2O losses and to more accurately estimate our national N2O inventories. For the Canadian Prairies, multi-year studies are needed to determine dung and urine derived N2O emissions under dry climate and different soil types. Our study evaluated N2O emissions in response to dung, urine, and unfertilized control plots following six animal excreta applications in 2009/10 and 2010/11, in experiments conducted in Swift Current, Saskatchewan; and, Lacombe, Alberta. Our results showed that pastures under dry climate can be “cold spots” for animal excreta derived N2O emissions (but exceptions occurred). For future research on this topic, we are working on the Living Labs Central Prairies (LL-CP) program, which is a model where farmers and scientists will work together to co-develop BMP’s. Specifically on animal excreta derived N2O emissions, we are planning to quantify urine derived emissions from animals grazing on poly crops vs. single species – information still scarce in the literature for dry climates.