Green manuring

Project coordinator: Birgitta Rämert, Department of Crop Production Ecology, SLU

Project colleagues: Anna Mårtensson, Sadhna Alström, Jan Lagerlöf, Peter Hambäck, Lena Gäredal, Ylva Eklind, Bengt Lundegårdh, Sven Hellqvist, Birgitta Båth and Elisabeth Ögren.

The aim of this interdisciplinary research programme is to develop locally adapted vegetable growing systems with the help of green manure crops. Green manure crops with nitrogen-fixing legumes add locally produced nitrogen to the cultivation system.

This project is investigating different ways to utilise the nitrogen fixed in green manure crops and how these affect plant nutrient supply to the commercial crop, attack by pests through effects on their population dynamics and internal quality of the produce. We are also investigating how crop security and the economy of the grower are affected. Within the programme, we are studying four different systems for using green manure in white cabbage growing:

• Direct incorporation of the green manure crop
• Intercropping of green manure crop and commercial crop
• Biodigestion of the biomass from the green manure crop
• Composting of the biomass from the green manure crop

Six commercial growers are participating in the experiments. The project also includes two large shared field trials, Uppsala and Umeå, where 10 researchers are collaborating. All aspects of green manuring are being weighed together to produce a growing system that is financially and organically sustainable.