Effective weed management strategy under the soil typic haplustepts for black gram through herbicide application

A field experiment was conducted during kharif season 2018 at Bihar Agricultural University, Sabour, to study the effect of different herbicides on weeds, growth and yield of blackgram (cv.“IPU 2-43”). Blackgram is a self pollinated pulse crop also known as urdbean, mash, black maple, etc. and is highly nutritious which can reduce the cholesterol level. Major weeds observed were Cynodon dactylon (grasses), Cyperus rotundus (sedges), Phyllanthus niruri, Solanum nigrum, and Mimosa pudica (Broad-leaved weed). The experiment was laid out in a randomized complete block design with three replications having eleven treatments comprising of weed check, different doses of pre-emergence and post-emergence herbicides, intercultural operation @ 20 and 40 DAS, and weed free. Pre-emergence followed by postemergence application such as Pendimethalin 30EC @ 0.75 kg a.i ha^-1followed by Imazethapyr @ 0.060 kg a.i ha^-1 (54.79%) significantly reduced the weed density 4.72 m^-2, weed biomass 6.46 (g m^-2) at 60 DAS than weedy check 9.69 m^-2, 11.99 (g m^-2) respectively and also provided highest weed control efficiency. However, the application of post-emergence herbicide quizalofop-p-ethyl 5 EC @ 0.05 kg a.i ha^-1 and fenoxaprop-p-ethyl 10 EC @ 0.10 kg a.i ha^-1 after preemergence of Pendimethalin did not control the weed effectively. Among herbicide treatments, pre-emergence fb post-emergence i.e., application of pendimethalin 30EC fb imazethapyr @ 0.75 kg a.i ha^-1 and 0.060 kg a.i ha^-1 respectively recorded the highest grain yield (925 kg ha^-1), net return (Rs 48549 ha^-1) and B:C ratio (2.65).