Use of green manure, catch crops, and deep rooted crops for nutrient management in an organic vegetable crop rotation

The results and conclusions from an unfertilized organic vegetable rotation are presented. It is discussed how catch crops, green manure crops and deep rooted crops have all been important tools in maintaining the fertility during the 9-year rotation experiment. The results indicate that these methods have helped to direct the available nitrogen towards crop use, by concentrating available nitrogen in upper soil layers and making nitrogen mainly available in the spring rather than in the autumn. Soil measurements indicate that soil N fertility has been increasing during the 9 years.