Effects of brown manure species, seed rate and time of application of 2,4-D on weed control efficiency, productivity and profitability in maize

Abstract

Weeds result in yield losses up to 40% in maize in India. Brown manuring can suppress weeds better and provide ecosystem services. It has been hardly studied in crops other than rice. It offers potential for adoption in maize, but needs to be optimized because maize differs from rice in growth habit and architecture and has no tillering capacity. Therefore, this study was undertaken to optimize brown manuring option(s) that involved two brown manure species, their mixture and seed rates, and the times of application of 2,4-D. Results revealed that all brown manuring treatments suppressed noxious weed Cyperus rotundus better than the recommended tank-mixture of atrazine + pendimethalin. Among them, a brown manuring option that involved 1:1 mixture of Sesbania bispinosa (12.5 kg seed/ha) + Crotalaria juncea (12.5 kg seed/ha) + 2,4-D 0.5 kg/ha applied at 35 DAS resulted in highest reduction in weed density (~91%). Another brown manuring option, i.e., Sesbania + Crotalaria (12.5+12.5 kg/ha) mixture and 2,4-D 0.5 kg/ha applied at 25 DAS gave similar weed suppression, and was superior to it on maize grain yield (~13.4%), gross return (~15.7%) and gross benefit:cost (~15.6%). This brown manuring would be a profitable weed management practice in maize. It may lead to sequester C and N in soil and provide ecosystem services as well