Functional divergence effects of intercropped faba bean and maize in organic production for forage increase mineral contents and reduces leaf spots

Abstract

Multispecies cropping systems contribute to sustainable agriculture with multiple ecosystem services. Effects of intercropping of organically managed maize and faba beans to silage on acquisition of mineral nutrients in shoots of both crops and on leaf spot progression in faba beans were investigated. Three field experiments were performed with maize and faba bean intercropped or grown separately. Intercropping increased shoot concentrations of K, Ca, Mg, Na, S and B in faba bean, and shoot concentrations of Cu, Zn and Mo in maize. Thus, the ecological complementary effects enhance feed quality. Disease severity index (DSI) of leaf spots in faba beans was reduced by intercropping by 42–57 %, partly due to an increased Cu acquisition at sites where the Cu availability was low. There was a significant negative linear relationship between Cu concentration in shoots and DSI of leaf spots. Total uptake of mineral nutrients per land area was greater in the intercropping system with a total LER > 1 for all mineral nutrients, except for P, Ca and Mn at one of the sites. Increased nutrient use efficiency, due to facilitative uptake from the soil, and the production of crops with higher contents of minerals compared with monocropping, are benefits of intercropped maize and faba beans.