EFFECT OF PLANTING GEOMETRY AND INTEGRATED WEED MANAGEMENT ON THE GROWTH OF WEED AND YIELD OF JIRASHAIL RICE

Abstract

Managing weeds sustainably to achieve desirable crop yields is a major concern worldwide. When the same weed management strategies are used, such as using similar herbicides excessively in a certain area to control weeds for a crop, weeds become resistant to that herbicide or technique, and gene flow from that resistant weed variant makes this condition worse. In this experiment, to solve this problem through proper weed control and get the highest yield of Jirashail rice, planting geometry (PG) and integrated weed management (IWM) methods were evaluated in the Agronomy Field Lab of BAU from August to November 2023. The experiment was laid out in an RCBD with three replications. The experiment was conducted with Jirashail rice with four PG (20 cm × 10 cm) (S₁), (20 cm × 15 cm) (S₂), (25 cm × 10 cm) (S₃), (25 cm × 15 cm) (S₄) and five different IWM practices such as W₀ (unweeded control), W₁ (Two hand weedings at 15 and 30 DATs), W₂ [Application of pre-emergence herbicide (Pretilachlor) followed by one hand weeding at 30 DAT], W₃ [Application of early post-emergence (EPE) herbicide (Acetachlor + Bensulfuron methyl) followed by one hand weeding at 30 DAT), W₄ (Application of pre-emergence herbicide (PE) followed by early post-emergence herbicide). The highest weed density and dry weight were achieved when the S₃W₀ treatment was applied. Though S₁W₄ treatment showed the lowest weed density and dry weight, rice grain yield was not that desirable here. However, the highest grain yield was observed at the S₄W₄ treatment with a minimum weed interference. The lower grain yield was observed at the spacing of 20 cm × 10 cm and unweeded control treatment (S₁W₀). From the study, it may be concluded that 25 cm × 15 cm planting geometry with the application of preemergence herbicide pretilachlor followed by early post-emergence herbicide could be recommended for Jirashail yield maximization as well as sustainable weed management.