Maize-legume systems under conservation agriculture

Soil fertility depletion due to land degradation and poor cropping diversity have resulted in poor crop yield in sub-Saharan Africa. On-farm experiments were conducted to determine the effects of conservation agriculture (CA)-based maize (Zea mays L.)-legume cropping systems and conventional tillage (CT) on soil properties and yield of maize. The experiments were laid out in a randomized complete block design with three replications. The experiments were continued for 3 yr from 2012 to 2014. The treatments were: CT with monoculture maize (CT-M), CA with monoculture maize (CA-M), CA-based maize-common bean (Phaseolus vulgaris L.) intercropping (CA-M+CB), CA-based maize-cowpea (Vigna unguiculata L.) intercropping (CA-M+CP) and CA-based maize-common bean rotation (CA-M-CB).Weed infestation in CA-based maize-legume cropping systems reduced over the years. Application of CA-based maize-legume cropping systems increased soil organic matter, total nitrogen, available phosphorus (Ava.P), and soil water infiltration rate by 37, 54, 12.3, and 327%, respectively, over CT-M. Maize grain yield increased by 54% in CA-M-CB over CT. The highest production efficiency was obtained from CA-M-CB. In conclusion, CA-M-CB followed by CA-based maize-legume intercropping were the best soil management practices as elucidated in higher soil fertility and stable yield. However, future research on CA-based cropping systems should be executed under various agro-ecologies and crop types.