Forage yield and nutritive value of maize and legumes intercropping in Northwest region of Vietnam

This study was conducted in the Northwest region of Vietnam to evaluate forage yield and nutritive value of intercropping maize with two legume species (soybean and black bean) under different row spacing arrangements. Results indicated that intercropping improved dry matter yield and particularly crude protein yield compared with sole maize, with maize–soybean intercrops outperforming maize–black bean combinations. Planting methods significantly affected growth and forage quality: Method 1 (maize 60 × 20 cm, legumes sown between two maize rows) produced the highest maize yield, while Method 3 (maize 90 × 20 cm, legumes sown between rows) increased the legume proportion and protein content in the mixture. The chemical composition and nutritive value of maize–legume mixtures were also improved, showing higher CP, TDN, and ME values and lower ADF and NDF compared with sole maize. These findings demonstrate that maize–legume intercropping is a promising solution to supply more nutritious forage for ruminants during the winter feed shortage in the Northwest region of Vietnam.