Growth and Productivity of Black Gram (Vigna mungo L.) as Influenced by Residual Effect of Triafamone Herbicide Applied for Transplanted Rice (Oryza sativa L.)

Abstract

Background: The major area under black gram are cultivated as rice fallow crop to harness the available soil moisture and other resources without application of any inputs as that of other input intensive crops. Weeds are one of the important biotic factors which affect the growth and yield of black gram. The weeds can be effectively managed in black gram by the herbicide applied in the previous crop viz., transplanted rice. Since, the black gram has quick ground cover, hence initial weed management is very much important. In order to manage the weeds in rice fallow black gram crop evaluation of Triafamone herbicide applied to the transplanted rice crop was carried out in succeeding black gram crop in terms of the growth and yield of black gram. Methods: Field experiments were conducted during Kharif, 2019 (July to August) and Rabi 2019-20 (November to January) at Wetland farm of Tamil Nadu Agricultural University, Coimbatore to study the residual effect of herbicides applied in transplanted rice on succeeding black gram growth and productivity. The experiment was laid out in a randomized complete block design with three replications. The treatments consisted of four doses (30, 40, 50 and 100 g/ha) of new rice herbicide Triafamone 20% SC each as pre emergence and early post emergence, along with check herbicides Pretilachlor 50% EC 750 ml/ha and Pyrazosulfuron ethyl 10% WP 15 ml/ha as early post-emergence along with farmers practice (two hand weedings), weed free and weedy checks. Result: The weed flora of the experimental field consisted of weed complex including grasses, sedges and broad leaved weeds. Among the different dose of herbicides applied, Triafamone 20% SC at 100 g/ha markedly suppressed the weeds growth. There were no phytotoxic effects of herbicides on succeeding black gram. Different doses and time herbicides applied in transplanted rice did not affect the germination of succeeding black gram. Higher weed control efficiency, growth and yield component and yield of black gram were recorded with the Triafamone at 40 g/ha as pre emergence and early post emergence application.