Soil tillage treatments were sampled in two parallel field experiments (conventional and organic farming) in this study (Fig. 1). Conventional and organic farming systems had unique crop rotations with individual fields at a different phase of their rotation (Table 1). Rotations contained mainly root and cereal crops, although grass and cabbage were also included in organic farming. Cover crops were grown during fallow periods when feasible. Conventional fields received yearly synthetic fertiliser applications and were treated bi-weekly with herbicides during the growing season. Organic fields received yearly cow manure (solid or slurry) applications of 20–40 t ha−1 yr−1. Organic field A in autumn 2010 did not receive manure because of the reduced nitrogen required by the following leguminous crop (wheat/faba). Tillage treatments received the same amounts of fertilisers and herbicides in conventional fields, or manure in organic fields. Organic fields received certification in 2004 and no synthetic fertilisers or pesticides have been used since 2002.