Weed Control in Maize (Zea mays) Intercropped with Soybean (Glycine max)

An experiment was conducted at Ranchi during wet season of 1990–92 to study the effect of cropping system and weed control on weeds and productivity of maize and soybean. Intercropping of maize with soybean, irrespective of their row ratios, effectively reduced the weed density and dry weight of weeds at 30 and 60 days after sowing compared to their pure cropping. The grain yield of maize under intercropping was at par with that obtained under its pure cropping but the drastic decrease (36–53%) in grain yield of soybean was noticed in intercropping systems compared with its sole cropping. Maize-equivalent yield in maize + soybean (1: 1) intercropping system made commendable improvement (5023 kg/ha) compared to remaining cropping systems. Hand weeding at 15 and 30 days after sowing was comparable with the pre-emergence application of pendimethalin 0.75 kg/ha in reducing population as well as dry matter production of weeds at 30 and 60 days after sowing. Pendimethalin 1.0kg/ha pre-emergence and fluchloralin 1.0kg/ha pre-plant incorporation proved as good as hand weeding in increasing the grain yields of maize and soybean. Hand weeding at 15 and 30 days after sowing gave the highest maize equivalent yield (5259 kg/ha) which was at par with that obtained with pendimethalin 1.0 kg/ha pre-emergence (4793 kg/ha).