Emission factors for estimating fertiliser-induced nitrous oxide emissions from clay soils in Australia's irrigated cotton industry

Peter Grace, Iurii Shcherbak, Ben Macdonald, Clemens Scheer, David Rowlings
2016 Soil Research  
As a significant user of nitrogen (N) fertilisers, the Australian cotton industry is a major source of soil-derived nitrous oxide (N 2 O) emissions. A country-specific (Tier 2) fertiliser-induced emission factor (EF) can be used in national greenhouse gas inventories or in the development of N 2 O emissions offset methodologies provided the EFs are evidence based. A meta-analysis was performed using eight individual N 2 O emission studies from Australian cotton studies to estimate EFs. Annual N
more » ... imate EFs. Annual N 2 O emissions from cotton grown on Vertosols ranged from 0.59 kg N ha -1 in a 0N control to 1.94 kg N ha -1 in a treatment receiving 270 kg N ha -1 . Seasonal N 2 O estimates ranged from 0.51 kg N ha -1 in a 0N control to 10.64 kg N ha -1 in response to the addition of 320 kg N ha -1 . A two-component (linear + exponential) statistical model, namely EF (%) = 0.29 + 0.007(e 0.037N -1)/N, capped at 300 kg N ha -1 describes the N 2 O emissions from lower N rates better than an exponential model and aligns with an EF of 0.55% using a traditional linear regression model.
doi:10.1071/sr16091 fatcat:egxvzzt55vfybkomsqh3b4ocsa