Eco-functional intensification by cereal-grain legume intercropping in organic farming systems for increased yields, reduced weeds and improved grain protein concentration
Résumé
Intercropping, i.e., simultaneously growing two (or more) species in the same field for a significant period of time but without necessarily concomitant sowing or harvest, is a practice aimed at eco-functional intensification. This chapter integrates a comprehensive amount of original data from field experiments conducted since 2001 on spring and winter cereal-grain legume intercrops in experimental and farm contexts in France and Denmark, in an attempt to generalise the findings and draw up common guidelines. We have shown that intercrops appear to be a useful agronomic solution for organic arable cropping, particularly in low-N input systems, to enhance: (i) yields because of a general improvement of environmental resource use; (ii) cereal grain protein due to a non-proportional competition for soil mineral N and other plant growth factors; and (iii) weed control compared to legume sole crops.