Productivity, Soil Fertility and Biodiversity in Organic Agriculture

The DOK long-term field experiment is comparing organic and conventional farming systems since 1978. The systems mainly differ with respect to fertilization and plant protection. The crop yields of the organic systems averaged at 20% of the conventional over three seven-year crop rotation periods. Nutrient input (N, P, K) in the organic systems was 34 – 51 % lower than in the conventional systems, indicating and efficient production. Soil quality as indicated by physical, chemical and biological measures is markedly higher in the organic systems. Organic systems of the DOK trial can therefore be regarded as efficient with respect to productivity and safeguarding environmental quality and biodiversity