Effectiveness of pre-emergence herbicides on weed population and yield of boro rice (cv. BRRI dhan58) under different dose

Weed management is crucial for optimal crop performance in rice cultivation. In this respect, an experiment was conducted at the Agronomy Field Laboratory (AFL), Bangladesh Agricultural University (BAU), Mymensingh, from December 2019 to May 2020 and aimed to evaluate the effectiveness of various herbicide treatments on weed management and crop performance in rice cultivation, focusing on the variety BRRI dhan58. The study included a control group and various herbicide treatments: half the recommended dose (RD), RD, and a double dose of pendimethalin, bensulfuron methyl + acetachlor, bensulfuron methyl + bispyribac sodium, pretilachlor, and butachlor. Eleven weed species from six families infested the plots. The results showed that double doses of pre-emergence herbicides resulted in lower weed populations (WP) (m-²), reduced weed dry weight (DW) (gm-2), and higher weed control efficiency (WCE %). The highest weed control efficiencies at 30 DAT were 94.58% for Bensulfuron methyl + Acetachlor and 94.38% for Pretilachlor. The double dose of Bensulfuron methyl + Acetachlor achieved the lowest WP and DW and the highest WCE. Crop performance improved significantly with the double dose of Bensulfuron methyl + Acetachlor, resulting in the highest PH, a more significant number of effective tillers (NET) hill-1, 1000-grain weight (TGW), grain yield (GY), straw yield (SY), biological yield (SY), and harvest index (HI). The second-highest GY was observed with the double dose of Bensulfuron methyl + Bispyribac sodium. The study concluded that the double dose of Bensulfuron methyl + Acetachlor was the most effective weed management strategy, leading to the highest grain yield in boro rice. These findings highlight that using a double dose of Bensulfuron methyl + Acetachlor not only offers superior weed control but also maximizes grain yield, making it the most effective weed management strategy for boro rice cultivation and a practical recommendation for farmers seeking to optimize productivity through targeted herbicide application.