Investigating the interplay between UK crop yields, soil organic carbon stocks and greenhouse gas emissions

Agriculture has the capacity to both emit and to remove green house gases (GHG) from the atmosphere. Soil organic carbon (SOC) is a major carbon sink and can be the target of carbon sequestration. SOC is also a major potential source of future emissions as conversion of land from pasture or forest to arable leads to significant emissions of CO2 plus N2O. We have investigated the relationship between UK crop yields, land use change and GHG emissions. Since 1950 UK crop yields have risen dramatically but since 2000 yields have begun to level out. There are currently a number of potential threats to future yields including climate change, water availability, pest pressure, and potential restrictions on the use of pesticides and fertilisers. Were uncropped land to be converted to arable land in order to compensate for lower yields then this would result in significant additional GHG emissions. We conclude that the maintenance or increase of crop yields is necessary in any strategy for climate change mitigation.