Brown manuring in maize (Zea mays): Effects on weed interference and crop productivity

A field experiment was undertaken during rainy (kharif) season 2017 at ICAR-Indian Agricultural Research Institute, New Delhi to study the effects of brown manuring on weeds and maize (Zea mays L.) productivity. Seasonlong weed infestation (∼unweeded control) resulted in the highest reduction (∼41%) in grain yield of maize. Among the brown manuring (BM) treatments, growing of 1: 1 mixture of Sesbania bispinosa (12.5 kg seed/ha) + Crotalaria juncea L. (12.5 kg seed/ha) supplemented with 2, 4-D 0.5 kg/ha applied at 35 DAS, resulted in the highest reduction in weed density (∼93%) and dry matter (∼94.4%). This BM, in these regards, was comparable with the atrazine + hand weeding (HW) at 35 days after sowing (DAS) and weed-free control treatments. All BM treatments suppressed noxious weed Cyperus rotundus, which was poorly or not controlled by the recommended tank-mixture of atrazine and pendimethalin. Weed-free control resulted in the highest values of maize plant dry-matter (∼210.6 g/plant), cob weight (∼155.9 g/cob), and grain yield (∼6.0 t/ha). The atrazine + HW, Sesbania + Crotalaria (12.5 + 12.5 kg/ha) mixture applied with 2, 4-D 0.5 kg/ha at 25 DAS, Sesbania 25 kg/ha with 2, 4-D 0.5 kg/ha at 25 DAS, and pendimethalin 0.75 kg/ha + atrazine 0.75 kg/ha treatments were comparable with weed-free control on maize grain yield.