Impacts of Intercropping Maize–Grass–Legume for Silage Production and Oversowing Black Oat for Lamb Grazing on Soil Fertility

Intercropping grasses and legumes could be an important strategy for sustainable food production in tropical weathered soils. This study aimed to assess the impact of intercropping systems comprising maize and grass with or without a legume for silage production and overseeded black oat overseeded for lamb grazing on crop production, root development and soil fertility under no‐till (NT). The cropping systems consisted of maize intercropped with palisade grass ( Urochloa brizantha cv. Marandu) with or without pigeon pea ( Cajanus cajan ) in the summer/autumn and black oat ( Avena strigosa ) overseeded in row or broadcast with superficial incorporation in the winter/spring. Maize forage mass for ensiling, maize grain yield, crop straw on the soil surface, root development and soil fertility were assessed. Despite an atypical period of drought in the first year, the addition of the legume to the intercropping system increased forage accumulation for silage, maize grain yield and crop straw by 13%, 8% and 53%, respectively, and ensured adequate soil cover for the cycling of soil nutrients for the subsequent crops. Harrowing to incorporate broadcast black oat negatively impacted silage production, maize yield and root development and stimulated C mineralization. It suggests that adjusting the density of intercropped species is a potential management strategy for tropical regions subject to drought, but further studies are needed.