Estimating nitrous oxide emissions from a dairy farm using a mechanistic, whole farm model and segregated emission factors for New Zealand
Tóm tắt
Nitrous oxide (N2O) emissions from agriculture are generally estimated using default IPCC emission factors (EFs) despite the large variation in measured EFs. We used a classification and regression tree (CART) analysis to segregate measured EFs from direct emissions from urine patches and fertiliser and effluent applications, based on temporal and site-specific factors. These segregated EFs were linked to simulations from the DairyNZ Whole Farm Model to obtain N2O emissions for a typical pasture-based dairy farm in New Zealand. The N2O emissions from urine patches, dung pads, and fertiliser and effluent application, as well as from indirect sources, were aggregated to obtain total N2O emissions for the farm-scale. The results, based on segregated EFs, were compared with those obtained using New Zealand-specific EFs. On-farm N2O emissions based on these segregated EFs were 5% lower than those based on New Zealand-specific EFs. Improved farm management by avoiding grazing, effluent, and N fertiliser application during periods of high risk for N2O emissions, or by the use of mitigation technologies such as nitrification inhibitors, could reduce annual farm scale N2O emissions.
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Tài liệu tham khảo
Li, 1992, Journal of Geophysical Research, D9, 9776