Weed biomass and yield of greengram (Vigna radiata) as affected by sequential application of herbicides in Indo-Gangetic Plains

Abstract

A field experiment was conducted during the rainy season of 2013 at the research farm of the ICAR-Indian Agricultural Research Institute, New Delhi to evaluate the performance of sequential application of herbicides for weed management in greengram [Vigna radiata (L.) Wilczek]. The experiment was laid out in randomized complete block design with 3 replications. The weed control treatments (12) were: pendimethalin @ 1 kg/ha pre-emergence (PE), pendimethalin @ 1 kg/ha PE + 1 HW at 30 days after sowing (DAS), pendimethalin @ 0.75 kg/ha PE + imazethapyr @ 50g/ha post-emergence (POE) at 30 DAS, pendimethalin @ 0.75 kg/ha PE + imazethapyr @ 75g/ha POE at 30 DAS, imazethapyr @ 50 g/ha POE at 20 DAS, imazethapyr @ 75 g/ha POE at 20 DAS, pendimethalin @ 0.75 kg/ha PE + quizalofop @ 50g/ha POE at 30 DAS, pendimethalin @ 0.75 kg/ha PE + quizalofop @ 75g/ha POE at 30 DAS, quizalofop @ 50 g/ha POE at 20 DAS, quizalofop @ 75 g/ha POE at 20 DAS, weed free and weedy check. Sequential application of herbicides was more effective than their one time application either PE or POE in suppressing weed growth in terms of density and dry weight. Pendimethalin @ 1 kg/ha PE + 1 HW at 30 DAS resulted in highest seed yield (1.10 t/ha), weed control efficiency (75.21%), lowest weed dry weight (6.02 g/m2), weed density (7.06 no/m2) and weed index (8.33%). However, this treatment did not differ significantly from pendimethalin @ 0.75 kg/ha PE + imazethapyr @ 75g/ha POE at 30 DAS. Therefore, sequential application of herbicides can be an effective alternative to manage weeds in greengram.