HERBICIDE EFFICACY IN MAIZE (ZEA MAYS L.): EFFECTS OF TILLAGE AND WEED MANAGEMENT ON WEEDS, SOIL MICROBES AND PRODUCTIVITY

Abstract

A field experiment was conducted during rabi 2020-21 at the AICRP on Weed Management Block, Central Farm, Odisha University of Agriculture & Technology (OUAT), Bhubaneswar, Odisha, to evaluate the combined effects of tillage and weed-management practices on weed biomass, weed nutrient capture, culturable soil microbial populations and maize productivity. Three main-plot tillage practices, namely conventional tillage (CT), zero tillage with paddy-straw mulch @ 5 t ha-1 (ZT+M) and zero tillage by dibbling (ZT), were combined with four subplot weed-management practices: pendimethalin @ 1 kg ha-1 as pre-emergence, tembotrione @ 120 g ha-1 as post-emergence, manual weeding and weedy check. The experiment was laid out in a split-plot design with three replications, comprising 12 treatment combinations per replication and 36 experimental plots. Weed biomass was recorded at 30, 60 DAS and harvest, while culturable populations of bacteria, fungi and actinomycetes were enumerated at 7, 14 and 21 DAS using the serial dilution and spread-plate technique. Nutrient capture by weeds in terms of N, P and K was determined at different crop stages and maize grain and stover yields were recorded at harvest. Conventional tillage recorded the lowest weed biomass, whereas ZT resulted in greater weed biomass. Pendimethalin effectively restricted weed biomass and nutrient capture. ZT+M supported comparatively greater populations of bacteria, fungi and actinomycetes than CT and ZT. Maize grain yield was highest under CT and statistically comparable with ZT+M, while pendimethalin recorded the highest yield among weed-management treatments. The study demonstrates the importance of integrating tillage, residue retention and timely weed management to balance weed suppression, soil biological activity and maize productivity.