It is hard to know how this summer will turn out. An exceptionally wet autumn and winter completely prevented the establishment of autumn-sown crops at Loddington and other local farms. There was just about time to drill spring varieties in those fields where we needed to do so for research, or considered that it would still be economically viable to do so for our farm business. Then the drought hit.
By June, livestock farmers were searching around for additional grazing as pasture and leys withered, recalling memories of the prolonged drought just two years ago. Social media were scattered with posts from normally successful arable farmers sharing images of drought stressed crops and professing that the continuing weather uncertainties and extremes were now making it impossible to maintain a viable business. Recent rain has provided a reprieve by increasing surface soil moisture, at least for now.
Loddington soil moiture deficit to June 2020, including the 2018 drought and exceptionally wet autumn/winter of 2019/20
Our research aims to contribute to our understanding of this issue. We want to see continuing economically viable food production on farms such as ours, to understand better how to reduce our greenhouse gas emissions and to sequester carbon in our soils.
Global warming potential of CO2 and N2O in compacted SoilCare project plots
Monitoring of greenhouse gas flux in compacted soils as part of our contribution to the EU-funded SoilCare
project reveals that carbon dioxide flux is higher in ploughed plots than in direct drilled plots. In these compacted conditions, nitrous oxide flux is higher in direct drilled plots. The amounts involved are very low, but because nitrous oxide has a global warming potential that is nearly 300 times that of carbon dioxide, the implications for climate change are that much greater. Looked at together, the global warming potential of greenhouse gases associated with ploughed and direct drilled plots is roughly equivalent. The additional emissions associated with multiple field operations in the ploughed plots mean that direct drilling has the lower impact.
Mean Soil Organic Carbon from ten Water Friendly Farming project fields
Reduced soil disturbance, whether through direct drilling or other practices such as incorporation of leys into the rotation, also has the potential to increase soil organic carbon. Data from local fields in the Water Friendly Farming project
study area reveal that this is currently around 3%, and typically, declines with soil depth. Increasing soil carbon helps to improve soil moisture retention during drought. It also has the potential to deliver public benefits such as improved water infiltration during storms, resulting in better water quality and ecology, and reduced downstream flood risk. At depth, stable forms of carbon represent an important potential carbon store, contributing to climate change mitigation.