STUDY ON DIFFERENT WEED MANAGEMENT APPROACHES IN AUS RICE AT SYLHET

Abstract

An experiment was conducted at the experimental field of Sylhet Agricultural University (SAU) to find out the effective weed management practices in Aus rice. There were eight treatments viz., Herbicide Rifit ( T1), Cicord (T2), T1 & T2 combination ( T3), NPK guti ( T4), Prilled urea (T5), weedy control (T6), weed free control (T7), and hand weeding (T8) with 3 replications. The rice variety was BRRI dhan55 and it was transplanted on 1 week of May and harvested on mid of July, 2014. Ten major weed species were recorded in the experimental plots. Among these four were board-leaved, two were grasses and the rest were sedges. The most prominent weeds were Cyperus iria, Sphenoclea zeylanica, Luduigia hyssopifolia, Cyanotis axillaris, Cyperus flavidus, Lindernia procumbens, Digitaria ischaemum, Leersia hexandra, Fimbristylis milieaceae. The highest weed population (10.04/m st ) was recorded in weedy check (T6) plots and the lowest weed density (0.74/m 2 ) was in weed free check (T7) followed by T3 treated plots. Yield and yield contributing characters like plant height, number of effective tillers per hill, panicle length and number of grain per panicle were significantly affected by different weed management approaches. The highest grain yield (1.64 t ha 2 ) was recorded using in the treatment of NPK guti (T4) which was followed by T3 and the lowest weed yield was recorded in weedy check plots (T6). The partial budget analysis showed that the highest net profit from rice cultivation was in treatment T3 followed by NPK guti (T4) and the lowest profit was in hand weeded plot (T8). The economic analysis also showed that two herbicide mixed used plots had the highest (1.29) benefit-cost ratio (BCR) which was almost similar to NPK guti (1.26). The results indicated that herbicidal treatments were profitable than other treatments. Besides, NPK guti fertilizer used at a time showed an alternative option in weed management in rice field. It may be concluded that herbicidal treatment or using guti NPK can be used as an alternative option when labor is a limiting factor in producing transplanted Aus rice.

-1