Seasonal rainfall impacts the relative performance of maize-legume intercropping systems in semi-arid Zimbabwe

Summary

Intercropping cereals and legumes may enhance system productivity by simultaneously producing grain for human consumption and crop residues for livestock feed. This study evaluated the effects of maize ( Zea mays ) intercropped with cowpea ( Vigna unguiculata ) or mucuna ( Mucuna pruriens ) on soil moisture dynamics, grain and forage yields, and household food and feed self-sufficiency under varying rainfall conditions. The experiment was conducted on five farms in Mutoko District, Zimbabwe, during the 2021/22 and 2022/23 growing seasons using a Randomized Complete Block Design with five treatments: sole maize, sole cowpea, sole mucuna, maize–cowpea intercropping, and maize–mucuna intercropping. Soil moisture was measured biweekly to 1.8 m depth. Each season, experimental sites were classified according to seasonal rainfall as dry (<450 mm), average (450–600 mm), or wet seasons (>600 mm).Intercropping performance was influenced by rainfall. Sole mucuna utilized more soil moisture than other cropping systems. In dry and average seasons, sole maize yielded 1,812 kg ha ⁻¹ of grain, 103% more than maize intercrops, and met annual household maize requirements. In wet seasons, maize–cowpea intercropping produced higher maize grain yields (3,273 kg ha ⁻¹ ) than sole maize (2,372 kg ha ⁻¹ ), with a land equivalent ratio of 2.18. Mid-season dry spells reduced grain yields across treatments but had limited effects on stover production. During wet seasons, mucuna-based systems generated the highest forage and crude protein yields, sufficient to feed five cattle during the dry season. These findings highlight that maize–legume intercropping can enhance food and feed production during relatively wet seasons