Forage yield components of irrigated maize–legume mixtures at varied seed ratios

Abstract

Forage availability limits livestock production in the world's semiarid regions. Dry matter (DM) yields of cereal forages, such as maize (Zea mays), can be increased by planting adapted legumes. Randomized complete block studies with three replications in 2005 and 2006 at Faisalabad, Pakistan compared forage DM yield of sole maize and maize mixed with cluster bean (Cyamopsis tetragonoloba), cowpea [Vigna unguiculata (L.) Walp.], and sesbania (Sesbania sesban) at 75:25, 50:50, and 25:75 seed ratios of the recommended seeding rate for maize and each legume, respectively. Maize DM yield was reduced (P<0.05) with each increase in legume seed ratio for all three legumes despite increases in maize plant height with increasing cluster bean and cowpea seed ratios. Cluster bean and cowpea mixture DM yields were decreased for the 75% legume seed ratio. Maize–sesbania mixture DM yield exceeded that of sole maize with a slight decrease for the 25:75 seed ratio compared to the 50:50 seed ratio (8.92, 10.86, 11.21, and 10.73Mg DMha−1 for sole maize and 75:25, 50:50, and 25:75 maize–sesbania seed ratios, respectively; 5% LSD for the legume×seed ratio interaction=0.44). Legume proportion of mixture DM yield was highly correlated to the seed ratio for all legumes (R>0.97, P<0.0001). It was correlated to cluster bean and cowpea mixture DM yield (R>−0.60, P<0.0001), but not sesbania mixture DM yield (R=−0.05, P>0.83). Land equivalent ratio was similar among mixtures averaging 1.23. Producers in semiarid regions can increase forage DM yield over sole maize by planting sesbania with maize.