Effect of Intercropping Three Legume Species on Growth and Yield of Sweet Corn (Zea mays) in Hawaii

Abstract

In Hawaii, there are many small farm holders. Intercropping may increase diversity of farm products, reduce input costs, and increase farm profitability. Two field experiments were conducted in Hawaii to study the effect of three legume species intercropped with sweet corn (Zea mays L.) on the growth, relative chlorophyll content, biomass, and yield of sweet corn. The treatments included corn + soybean (CS), corn + bush bean (CB), corn + cowpea (CC), and corn alone (CO; control). In the first growing season, 30 days after planting, relative chlorophyll content of corn leaves was significantly higher in CC treatment with 53%, 56%, and 68% compared with CB, CS, and CO, respectively. While, in the second growing season, 30 days after planting, relative chlorophyll content of corn leaves was significantly higher in CC treatment with and 31%, 33%, and 66% compared with CB, CS, and CO, respectively. Corn plants in the CC treatment were significantly taller and had greater leaf area than those in other treatments. Fresh and dry weights of corn biomass, corn + legume biomass (with and without pods), and fresh weight of corn ears were all significantly higher for the CC treatment as compared with the other treatments. Mean fresh weight of corn ears under CC treatment increased by 9.9%, 35.1%, and 53.5% compared with CB, CS, and CO, respectively. The results suggested that lower competition and/or the contribution of fixed N in the CC treatment contributed to the better growth of corn.