Conservation agriculture effects on weed dynamics and maize productivity in maize- wheat- greengram system in north-western Indo-Gangetic Plains of India

Conservation agriculture (CA) can promote sustainable crop intensification. However, weeds are the major constraints under CA, in the initial years. Nitrogen (N) management under CA is also crucial. A field experiment was undertaken to study the effect of conventional tillage (CT) and CA with and without residue using 75 and 100% recommended N dose on weed dynamics and crop productivity during 2018-19 and 2019-20 in maize (Zea mays L.) under maize - wheat (Triticum aestivum L.) - greengram (Vigna radiata (L.) Wilczek) cropping system at ICAR-Indian Agricultural Research Institute, New Delhi. Nine CA-based treatments and one conventional tillage were laid out in a randomized complete block design with three replications. CA-based zero till (ZT) bed planting systems with residue retention resulted in significant reductions in total weed density and biomass compared to CT. Permanent broad bed with residue using 75% N resulted in 34% lesser weed density than CT. Among the CA-based treatments, the permanent broad bed with residue using 100% N resulted in ~ 22% higher maize grain yield than CT (5.72 t/ha) with 36% higher net returns than CT owever, the permanent broad bed with residue using 75% N was found comparable in this regard and may be recommended for sustainable maize production under the maize-wheat-green gram system in north-western Indo Gangetic Plains of India.