EFFICACY OF HERBICIDES AND THEIR EFFECT ON YIELD OF TRANSPLANTED AUS RICE

Abstract

A field experiment was carried out at the Agronomy Field Laboratory, Sher-e-Bangla Agricultural University, Dhaka, during the period from March-August, 2015 to evaluate the efficacy of herbicides and their effect on yield of transplanted aus rice (BRRI dhan 48). This was a single factor experiment with eighteen treatments, namely T : Propyrisulfuran (500 ml/ha), T 2 : Propyrisulfuran (750 ml/ha), T 3 : Propanil (3750 g/ha), T 1 : Propyrisulfuran + Propanil (500 ml/ha + 3750g /ha), T 5 4 : Propyrisulfuran + Propanil (500 ml/ha + 2916.7g/ha), T 6 : Propyrisulfuran + Propanil (500 ml/ha + 2500 g/ha), T : Propyrisulfuran + Propanil (500 ml/ha + 2083.3 g/ha), T 8 7 : Propyrisulfuran + Propanil (500 ml/ha + 1666.7 g/ha), T : Propyrisulfuran + Propanil (500 ml/ha + 1250 g/ha), T : Propyrisulfuran + Propanil (750 ml/ha + 3750 g/ha), T 11 10 : Propyrisulfuran + Propanil (750 ml/ha + 3125 g/ha), T : Propyrisulfuran + Propanil (750 ml/ha + 2500 g/ha), T : Propyrisulfuran + Propanil (750 ml/ha + 1875 g/ha), T 14 13 : Propyrisulfuran + Propanil (500 ml/ha + 900g/ha), T : Propyrisulfuran + Propanil (750 ml/ha + 900 g/ha), T : Acetochlor 14% + Bensulfuron methy l 4% (2000 g/ha (premix), T 17: 16 Bispyribac sodium + Pyralosulfuran ethyl (150 g/ha + 150 g/ha) and T (Untreated check). The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Twenty-two different weed species infested the field among which Shusni (Marsilea quadrifolia), Behua (Cyperus difformis) and Moyurleja (Leptochloa chinensis) dominanted throughout the growing period but controlling Moyurleja (Leptochloa chinensis) was so hard and could not be controlled till harvesting. Results show that treatment T 18 recorded the lowest weed population at 7, 14, 21, 28 and 45 DAA

9 (days after Application) while the highest weed population was recorded from the control treatment T 18 . No. of total tillers hill -1 (12.87), no. of effective tillers hill (11.52), tiller length (.102.40 cm), panicle length (24.03 cm), no. of secondary branches panicle

(25.07), filled grains panicle 1 -1 (118.90), total grains panicle- ), straw yield (4.64 t ha-1), biological yield (8.4 t ha -1 1 -1 (125.4), grain yield (3.8 t ha ) and harvest index (50.08 %) were obtained highest from T 9 treatment. Whereas, T (Untreated check) recorded the lowest values in all cases except no. of unfilled grain panicle- 18 1 ,

no. of non effective tiller hill (3.17) and 1000 grain weight. It can be concluded from the above results that treatment T : Propyrisulfuran + Propanil (500 ml/ha + 1250 g/ha) performed better than other herbicidal treatments.