The impact of leftover herbicide residue applied to okra on weeds and crops of subsequent blackgram

Abstract

In the present study, the impact of residual herbicide was studied from previous applications on okra plants, explicitly concerning the growth of weeds and subsequent black gram crops. The relative density of different weed species was determined, revealing that Echinochloa colonum had the highest density at 16.56% and 12.88%, followed by Leptochloa chinensis at 13.01% and Acrachne racemosa at 10.82%. However, within the group of sedges, Cyperus rotundus and Cyperus haspan had a greater relative density of 13.01% and 9.79%, respectively. The weed-free control treatment achieved the highest seed output of black gram, followed by two manual weeding on the 20th and 40th DAS. The herbicide residue resulted from application of metribuzin 500 g ha-1 on 3rd DAS, followed by post-emergence (POE) application of quizalofopethyl 50g ha-1 on 20 DAS recorded higher plant height 5.7%, dry matter production 32.7%, clusters plants-1 33.3%, pods plant-1 79.6%, grain yield 41.0%, halum yield 44.7%, nitrogen uptake 54.3%, phosphorus uptake 117.5%, and potash uptake 81.8% as compared to the weedy check.