The impact of weather on nitrous oxide emissions from arable land in the UK. ID - 20143259338
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The application of nitrogen (N) fertiliser to crops is a major source of nitrous oxide (N2O) emissions, a potent greenhouse gas. A key driver of the direct N2O emissions from soil following the application of N fertiliser is the soil moisture content, and hence the weather conditions during the year can have a large impact on the emissions. Annual emissions were measured in 24 field experiments from 2010 to 2012 in England and Scotland, assessing the effect of ammonium nitrate fertiliser from nil to 240% of the recommended N rate. With respect to the 30 year mean (1981-2010), all sites were drier than average in 2010 and wetter than average in 2012. However in 2011, the English sites were very dry (c. 70% of the 30 year mean) and the Scottish site was wet (c. 135%). The statistical model identified rainfall as a key driver of N2O emissions. The clay content and an interaction between clay and rainfall, a proxy for water filled pore space, were also identified as key determinants of emissions. Nevertheless, the results suggest that the emission factor for a specified clay content and nitrogen application rate was less than the 2006 IPCC default of 0.01.