STUDY ON DIFFERENT WEED MANAGEMENT APPROACHES IN T. AMAN RICE IN SYLHET REGION

Abstract

An experiment was conducted in the farmer’s field of Mr Ripon Baddi, in the village of Hasimpur, Jalalpur union in the South Surma Upazila, Sylhet to find out the effective weed management practices in Transplanted Aman rice. There were 7 (seven) treatments namely two commercially available herbicides and their combination, hand weeding, farmer’s practices, weed free control, and weedy control were included. The variety BR 11 was transplanted on August, 09, 2013 and harvested on November 12, 2013. Nine weed species were recorded in this trial. Among these three were board-leaved, four were grasses and the rest were sedges. The most prominent weeds in the experiment were Panicum repens. Digitaria sangunalis, Leersia hexandra, Fimbristylis milieaceae etc. It was found that the important values and relative density among the nine weed species, Panicum repens was found higher at both 25 and 50 DAT where the lowest importance value and relative density was observed in case of Monochoria vaginalis. The highest weed population (79.63 m- ) was found in T7 treatment (weedy cheek) and the lowest weed population (18.82) was found in T3 2 at 25 DAT and no weed was found in weed free treated (T6) plots. 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 management approaches treatment T3 (Rifit at 7 DAT+ Gashmara at 14 DAT) produced the tallest plant ((145.4 cm), highest number of effective tillers hill (13.30), highest panicle length, highest number of grain per panicle and higher grain yield (5.33 t ha -1 ) in the treatment T3 (Rifit + Gashmara). Due to effective weed control was done, the ultimate reflection of this treatment was appeared and that’s why the highest grain yield (5.33 t ha -1 ) was recorded. Harvest index was differed significantly with different treatment where T3 (Rifit + Gashmara) have the highest index (39.62) which was at par with all the treatments except weedy cheek (T7). The highest net profit from rice cultivation was in treatment T3 which was almost double from all the treatments except T7 and the lowest profit was in no -1 weeding plot which was about four to five times lower than the treatment T3. The partial budget analysis also showed that treatment T3 (i.e. herbicide application two times) maximized the profit and the highest (1.85) benefit-cost ratio (BCR). It may concluded that herbicidal treatments were profitable than any other treatments. So use of herbicides may be an alternative in controlling weeds more easily and cheaply when there is labor crisis.