Influence of height of maize variety on the productivity of intercropped maize ( Zea mays L.) and cowpea ( Vigna unguiculata (L.) Walp)

Abstract

A 2-year field study was conducted in Nigeria to compare the productivity of intercropped and monoculture maize and cowpea as influenced by the height of maize in the intercrop. During the 1994 and 1995 cropping seasons, IT 84E-124, a semi-erect, early-maturing and photoperiod-insensitive cowpea cultivar, was planted with "Afo", a short (1.2 m), early maturing, less vegetative, and AMRSR-Y, a tall (1.5 m), improved open-pollinated and of medium maturity group maize cultivars in a row intercropping. Yield components and grain yield of maize and cowpea were lower under intercropping than in monoculture systems. Intercropped cowpea yields were decreased by 29 and 26% under the short and tall maize cultivars, respectively, while the yields of intercropped maize were reduced by 11 and 33% for the short and tall cultivars, respectively, across the two seasons. Land equivalent ratio (LER) was, however, greater with the shorter maize cultivar than with the taller cultivar (1.60 vs 1.41), and was greater with the intercrops than with the monocultures (1.51 vs 1.00) across the two seasons. The results of this study indicate that although intercropping may result in decreases in the yield of one or both of the component crops in a maize-cowpea mixture, the productivity of a unit land area is higher with intercropping than with monoculture. The higher LER with the shorter maize cultivar in this study suggests that intercropping may be more remunerative when short and less vegetative cereal cultivars are used in mixtures with legume crops.