Grain legumes in organic cropping systems

Summary

Grain legumes are valuable protein and energy sources in animal feeds and in human diets low in meat. Furthermore, grain legumes strongly benefit the cropping system, via biological fixation of atmospheric N2 - a fundamental process for maintaining soil fertility in organic farming systems. Other positive effects in the crop rotations are recycled N-rich crop residues and the break-crop effect in cereals-rich rotations. However, yield variability in grain legumes is well known and related to intolerance to water stress and harvest difficulties either because of lodging or late maturity. Grain legumes seeds also vary in quality, mainly due to environmental conditions and together with a weak competitive ability towards weeds and pathogen attack like e.g. Ascochyta spp. they may be less favoured in organic crop rotations.
There is a general need to increase grain legume protein production in Europe to meet an increasing demand. A certain import of conventionally produced protein feed sources is presently allowed on organic farms, e.g. soybean meal, free of genetically modified soybean grain, and oilseed rape cakes. However, from 2005 all feed used in animal production must be organically produced according to EU regulations. In that perspective evaluation of potentials for increased protein production via the growing of grain legumes in organic cropping systems is urgent.