In a long-term field trial (DOC; = bio-Dynamic, bio-Organic, Conventional) at Therwil, Switzerland, agricultural production systems have been compared since 1978. The production systems differ mainly in the amount and form of fertiliser and plant protection strategy. Crop rotation and soil tillage were the same. In the most prominent systems soil microbial properties were investigated for the first time after two crop rotations in 1990. In 1998, after 3 crop rotations, soil microbial properties were investigated in all field plots.
Conclusions
Agricultural systems exert distinct effects on chemical and microbiological soil properties, prominently the bio-dynamic system with the application of composted manure. Part of the influence on microbiological parameters appears to be indirect through chemical properties. The differentiation of the systems remained stable for the last eight years of the trial
