Mixed cropping of maize or sorghum with legumes as affected by long-term phosphorus management

Abstract Mixed cropping may lead to complementary utilization of resources, but the plant-plant interactions are very complex and also dependent on agronomic practices, such as phosphorus (P) supply. In order to evaluate to what extent mixed cropping with legumes benefits plant P nutrition in dependence of P availability, experiments are required with a wide range of P supply. The objective of this study was to assess the P nutrition of sole cropped cereals and cereal-legume mixtures as affected by inorganic and organic P fertilizers in single and combined applications. Maize (Zea mays) and sorghum (Sorghum bicolor) in sole cropping and combined with runner bean (Phaseolus coccineus) and lupine (Lupinus angustifolius, Lupinus mutabilis) were cultivated in three consecutive years from 2013 to 2015 on plots of a long-term field experiment established in 1998 with nine P fertilizer treatments. Crop biomass yields and nutrient uptakes were analyzed as well as chemical and biological soil properties. On average over the three experimental years and all fertilizer treatments the highest yields were measured for maize in sole cropping (14.9 Mg ha−1) followed by maize + bean (13.8 Mg ha−1), sorghum (10.9 Mg ha−1), and sorghum + lupine (9.75 Mg ha−1)(p