Influence of Intercropping Maize with Cowpea on Forage Yield and Quality

In this study, maize (Zea mays L.) and cowpea (Vigna unguiculata L.) were intercropped in different sowing densities and their monocropping equivalents and tested to determine the best intercropping system on forage yield and quality. Maize was cultivated alone 75 000 plants ha^-1 (SM) and intercropped with cowpea as follows: 75 000 plants ha^-1 of maize and 37 500 plants ha^-1 of cowpea (MC₁), 75 000 plants ha^-1 of maize and 50 000 plants ha^-1 of cowpea (MC₂) and 75 000 plants ha^-1 of maize and 75 000 plants ha^-1 of cowpea (MC₃), in rows alternating with maize. The highest dry matter yield was produced by MC₃ (20.6 t ha^-1), and the lowest by SM (19.3 t ha^-1). All intercropped systems had higher crude protein content MC₁ (96 g kg^-1 DM), MC₂ (107 g kg^-1 DM) and MC₃ (120 g kg^-1 DM) than the monocrop maize (76 g kg^-1 DM). Intercropping of maize with cowpea reduced neutral detergent and acid detergent fiber content of harvested forage, resulting in increased forage digestibility. Intercropping maize with cowpea could substantially increase forage quantity and quality, and decrease requirements for protein supplements as compared with monocrop maize.