Evaluation of herbicides and their application techniques for control of weeds in transplanted onion (Allium cepa var Cepa I.).

摘要

A field experiment was conducted during kharif 2001, in Coimbatore, Tamil Nadu, India, to evaluate the herbicides and their application techniques for control of weeds in transplanted onion. Oxyfluorfen at 150 kg/ha and pendimethalin 750 kg/ha gave excellent control of weeds by reducing total weed density and biomass at earlier stages and recorded higher yield. Higher weed density and biomass were recorded with fluchloralin at 1000 kg/ha, which was found ineffective in enhancing the bulb yield of onion. Oxadiargyl at 75 kg/ha gave moderate control of weeds and increase in bulb yield. Among application techniques, knapsack sprayer performed better in controlling weeds and improving the yield, followed by power sprayer. The sandmix broadcasting recorded lower weed count and weed biomass at early stages, but it registered lower yield due to inefficacy in control of weeds at later stages of crop growth. Herbigation recorded higher yield than sand-mix broadcasting. Treatment combinations of oxyfluorfen either with knapsack sprayer or with power sprayer recorded least weeds count and biomass and greatly enhanced yield. Pendimethalin either with sand-mix broadcast or with herbigation, oxadiargyl with knapsack sprayer and fluchloralin with herbigation were also effective in enhancing the onion bulb yield. Hand weeding showed poor results in terms of increasing yield compared with all herbicides except fluchloralin. Unweeded control gave least weed control and bulb yield.