Intercropping of Maize and Winged Bean

Maize (Zea mays L.) and winged bean [Psophocarpus tetragonolobus (L.) DC.] have complementary growth habits, biomass production, and protein concentrations. We evaluated yield and protein complementation between maize and winged bean to determine if intercropping can improve the quantity and quality of maize silage. An early and a late-maturity corn hybrid were intercropped with ‘Tpt1’ winged bean at plant densities of 35 900 and 46 500 plants ha⁻¹ in 1984 and 47 500 plants ha⁻¹ in 1985 near Lexington, KY. In 1984, increased plant density resulted in increased maize vegetation, grain, vegetation N, and grain N yields per hectare (16, 21, 19, and 28%, respectively), while intercropping reduced maize grain yield and grain N yield per hectare by 8% each and reduced winged bean vegetation N concentration by 11% and yield per hectare by 40%. Intercropping winged bean with early maize produced 14% more biomass and 39% more N per hectare than did the reference early maize monoculture at post maize physiological maturity. In 1985, intercropping reduced maize vegetation, grain, and grain N yields per hectare (7, 14, and 14%, respectively), and reduced winged bean vegetation yield, N concentration, and N yield per hectare (58, 7, and 61%, respectively). Intercropping with early maize produced 18% more biomass and 67% more N per hectare, whereas intercropping with late maize produced 11% more biomass and 46% more N per hectare than did the respective monoculture maize. Land equivalency ratios for both dry matter and N yields per area were greater than unity for each plant density and intercropping system. Intercropping of maize with winged bean may provide greater biomass and improved protein content of silage in a temperate climate. Point contribution of Kentucky Agric. Exp. Stn. and USDA-ARS. Journal no. 90-3-107.