Weed growth, productivity and profitability of blackgram as influenced by pre- and post-emergence herbicidal application

The field experiment was conducted at the Research Farm of the Punjab Agricultural University, Ludhiana during rainy season 2022 and 2023 to study the effect of pre- and post-emergence herbicides on the weeds, growth, productivity and profitability of blackgram. The experiment consisted of ten treatments replicated four times in a randomized complete block design. Two hand weeding significantly reduced the weed biomass and density followed by application of imazethapyr 75 g/ha as well as 50 g/ha at 15 days after sowing (DAS). In 2022, more frequent rains were received than in 2023, which resulted in several flushes of weeds. As compared to weedy check, pre-emergence (PE) application of imazethapyr 50 g/ha at 15 DAS in 2022 and pre-mix pendimethalin + imazethapyr 450 g/ha as well as 750 g/ha in 2023 showed significant superiority in managing weeds and increasing crop growth. On the basis of pooled mean, application of imazethapyr 50 and 75 g/ha at 15 DAS and pendimethalin + imazethapyr 750 g/ha (PE) resulted in 97.8, 88.1 and 84.4% higher grain yield over weedy check. On pooled mean basis, the highest net returns were provided by imazethapyr 50 g/ha at 15 DAS (Rs 61804/ha) followed by hand weeding (Rs 59812/ha), imazethapyr 75 g/ha at 15 DAS (Rs 56618/ha) and pendimethalin + imazethapyr 750 (Rs 54650/ha). It can be concluded that imazethapyr 50 g/ha at 15 DAS or pendimethalin + imazethapyr 750 g/ha can be applied in Kharif blackgram for managing weeds effectively and obtaining high productivity and profitability.