Chemical weed management in Brassica rapa var. yellow sarson

Abstract

Field experiments were conducted for three years at Pulses and Oilseeds Research Station, Berhampore, Murshidabad, West Bengal, India during rabi 2008, 2009 and 2010 to develop an efficient chemical weed management practice with newer herbicidal molecules in yellow sarson. The experiment was laid out in a randomized block design with three replications having eleven treatments. Experimental results revealed that highest seed yield (1456 kg ha^-1) was recorded under the treatment twice hand weeding and lowest with weedy check (910 kg ha^-1). Twice hand weeding recorded 60% higher seed yield over weedy check. Application of chemical herbicides significantly improved the seed yield over W0 at 5% level of significance.. Among the chemical weed control measures, application of Pendimathalin @ 1 kg a.i./ha (PE) recorded highest seed yield (1320 kg ha^-1) of yellow sarson, which was found at par with application of Pendimathalin @ 1.5 kg a.i./ha (PE), Fluchloralin @ 1.5 kg a.i/ha (PPI) and Clodinafop @ 0.06 kg a.i./ha ( 25-30 DAS). Chemical weed management practices increased the seed yield of yellow sarson by 25.3 to 45.1% over weedy check. Highest weed control efficiency (86.4%) was recorded with hand weeding twice. Significant reduction in the total weed density and total weed dry weight were found with the application of chemical herbicides at 5% level of significance. Among the chemical herbicides Pendimathalin @ 1 kg a.i./ha (PE) recorded highest weed control efficiency (81.7%). Chemical weed control measures increased the total microbial population by 26.5 to 89.4% over weedy check and 6.6 to 59.6% over twice hand weeding and thus proved to be environmentally safe and economic for managing weeds in yellow sarson.