Comparative Analysis of Soil Fertility, Productivity, and Sustainability of Organic Farming in Central Europe—Part 2: Cultivation Systems with Different Intensities of Fertilization and Legume N₂ Fixation as well as Perspectives for Future Development

In the course of the broad expansion of organic farming, a considerable increase in the number of different cultivation types has also occurred. Compared to the formerly ideal forms with arable farming and animal husbandry around 0.5–1.0 LU ha−1 and the corresponding use of organic manure, an increasing differentiation of cultivation systems can be observed today. There are market crop systems without livestock and purchased fertilizer with less than 20% legumes and forage cropping systems with more than 2.5 LU ha−1 livestock and a cultivation of grain and forage legumes of more than 50% in the crop rotations. From a long list of corresponding survey studies of farms in agricultural practice as well as a number of important long-term field trials, in this overview paper it was possible to investigate and to discuss both the manifold possibilities and the limitations of intensification in organic agriculture by a comparative analysis of results from a wide range of cropping systems from Central Europe. The short-term as well as the long-term effects on the development of yield and quality performance of crop rotations, nutrient management, and soil fertility, as well as of important environmental effects, were quantified, and aspects of further development and sustainability of organic farming systems were shown in detail