EVALUATION OF HERBICIDAL EFFICACY AND RESIDUAL ACTIVITY ON DIRECT SEEDED BORO RICE

Abstract

An experiment was conducted at the Agronomy field laboratory, Sher-e-Bangla Agricultural University, Dhaka, from November 2014 to April 2015 to evaluate the different herbicidal efficacy on weed control and growth & yield of boro rice cv. BRRI dhan50. The experiment comprised nine treatments viz. Acetachlor + Bensulfuran (Premix) @ 750 g ha -1 , Pyrazosulfuran-ethyl @ 150 g ha -1 , Bispyribac Sodium @ 150 g ha , Pretilachlor @ 1 L ha -1 , Pretilachlor+ Triasulfuran@ (1 L + 10 g) ha -1 , Propyrisulfuran + Propanil @ (0.5 L + 1 kg) ha -1 , Propyrisulfuran + Propanil@ (0.38 L + 1.5 kg) ha , Two hand weeding (20 and 40 DAS) and Weedy check.The experiment was laid out in randomized complete block design (RCBD) with three replications. Sixteen weed species belonging to seven families were observed in the experimental field. Weed population, weed dry weight and weed control efficiency were significantly influenced by herbicidal treatments. The highest weed population and dry weight were observed in unweededcontrol condition compared to other treatments. Application of Propyrisulfuran + Propanil (0.38 L + 1.5 kg) ha -1 showed the best performance to control all kind of weeds found in the field and its residual activity remained upto 45 days.Yield contributing characters and yield of BRRI dhan50 was significantly influenced by weed control treatments. The highest number of effective tillers hill -1 , grains panicle , 1000grain

weight, grain yield, straw yield and harvest index were obtained from the application of Propyrisulfuran + Propanil (0.38 L + 1.5 kg) ha -1 . Weed control had pronounced influence on yield (5.50 t ha -1 ) of BRRI dhan50 and 46.55% yield was lost in unweeded control condition. It can be concluded that application of Propyrisulfuran + Propanil (0.38 L + 1.5 kg) ha -1 may be used for the best performance of BRRI dhan50. However, in practical point of view the application of Propyrisulfuran+ Propanil (0.5 L + 1 kg) ha -1 may consider for producing second highest yield of BRRI dhan50. -1 -1 -1