The soil biota are a vital component of belowground systems, driving many key processes such as nutrient cycling, underwriting soil structural integrity and providing crucial ecosystem services to the wider environment. In agricultural systems, tillage practices are known to impact upon both the soil biota and surface erosion processes, but little is understood about the relationships between these three factors. This work addresses this issue within the framework of an EU Life/ Syngenta project “Soil and water protection for northern and central Europe” (SOWAP). Within this component of the SOWAP programme, we are determining the influence of different soil management practices on the size and overall composition of the soil microbial community and relating it to the propensity for erosion, at a variety of spatial scales. Soil microbial communities at two sites in the UK (Tivington, Somerset and Loddington, Leicestershire) are being studied. Microbial biomass and phenotypic structure, measured using PhosphoLipid Fatty acid Analysis (PLFA), are being used to determine the effect tillage has on these microbial communities. The field sites have been split into differing land management practices on the same slope. Temporal trends in microbial properties are being measured, along with erosion rates and a wide range of other soil, agronomic and ecological parameters, measured by other project partners. To date, the field trial data shows no significant tillage treatment effects upon microbial biomass C at either site after six months application of each treatment. However, both total microbial biomass and community structure are significantly different between the two UK sites. PLFA results indicate differences in microbial community in relation to tillage treatments.

The field trials are being supported by small-plot rainfall simulations in the field and by highly-controlled laboratory microcosms using manipulated microbial communities and controlled rainfall, to further elucidate microbial effects on soil erodibility. Preliminary results relating microbial community structure to erosion at the variety of scales being studied will be presented.