Journal of Research in Weed Science

Abstract This study was performed to evaluate the weed density and weed control efficiency (WCE) on transplanted rice under different treatments at a farmer’s field, Bhanu-11, Rupakot, Nepal during Rainy season of 2017. Ten treatments (one manual weeding at 21 days after transplanting (DAT) (T₁); two manual weeding at 21 and 42 DAT (T₂); three manual weeding at 21, 42, and 63 DAT (T₃); single cono weeding at 21 DAT (T₄); double cono weeding at 21 &42 DAT (T₅); triple cono weeding at 21, 42, and 63 DAT (T₆); butachlor as pre emergence (T₇); butachlor with single manual weeding at 21 DAT (T₈); butachlor with double manual weeding at 21 & 42 DAT (T₉) and weedy check (T₁₀) were laid in randomized complete block designs (RCBD) with three replications. At 30 DAT, the highest weed density was recorded at unweeded check (T₁₀) while it was the lowest at butachlor with double manual weeding (T₉). At 60 DAT the effective weed control method on weed density was found to be double manual weeding (T₂). At 90 DAT triple cono weeding (T₆) was found to be more effective on controlling weed density (30) and was at par double manual weeding (T₂), double cono weeding (T₅) and butachlor with double manual weeding (T₉). WCE was the highest in the plot treated with butachlor with double manual weeding at 21 and 42 DAT (T₉) and the lowest in the plot treated with butachlor pre emergence (T₇) at 30 DAT. At 90 DAT, WCE in the plot treated with triple weeding (T₆) was found the highest (78.63%) and the lowest in the plot treated with butachlor as pre emergence (T₇) (26.14%).

Abstract To evaluate most economical and efficient weed management practices in dry direct seeded rice, a field experiment was conducted at research block of AFU Rampur, Chitwan during the Kharif 2016 season. The treatments consisted of two establishment practices viz., zero till and conventional tillage and eight weed management practices such as weedy check, weed free, Pendimethalin followed by hand weeding at 20 DAS 1 kg a.i ha^-1, Pendimethalin followed by 2, 4-D ethyl ester at  25 DAS 1 kg a.i ha^-1, pendimethalin followed by bispyribac-Na at 25 DAS at 25 g a.i ha^-1, pendimethalin followed by ethoxysulfuron at 25 DAS 25 g a.i ha-¹, pendimethalin followed by penoxsulam at 25 DAS 25 g a.i ha^-1, pendimethalin followed by (ethoxysulfuron + bispyribac-Na. The experiment was conducted in split plot design with three replications. The result of experiment showed that non-significant difference was notice among the establishment method. However, significant difference was observed in weed management practices in all the traits expect number of weeds m^-2, number of weed species m^-2, and dry weight of broad leaf, narrow leaf and sedges weeds. The higher number of weeds m^-2 was found in weedy check plot which resulted in higher weed infestation at all the stages as compared to other weed management practices. Application of pendimethalin followed by hand weeding at 20 DAS recorded higher weed control efficiency which reflected in higher yield of 4202 kg ha^-1 was recorded under this treatment as compared to weedy check plot (1292.13 kg ha^-1) but rest of the treatments are statistically at par with other weed management practices.

Abstract A field experiment was conducted to assess the growth, productivity and profitability of rice (Sukhadhan-3 variety) under different methods of weed management at Bhanu-11 Rupakot, Tanahun during rainy season 2017. The experiment was laid out in randomized complete block design with three replications and ten treatments. The phenological, growth, yield and yield attributing characters were observed in the experiment. Results revealed that maximum grain yield (5.91 ton ha^-1) was obtained in application of butachlor at 4 days after transplanting (DAT) which was statistically at par with all other treatments except single manual weeding, single cono-weeding and non-weeding plots (3.66 ton ha^-1). The highest grain yield obtained from this treatment was might be due to higher number of effective grains per panicle (203 grains), less sterility (6.4%), high test weight (30.7g) with good harvest index (38.4%). Although the single application of butachlor as pre emergence spray showed highest grain yield which seems economically viable and profitable practice to the farmers but it is not environmentally safe to the whole universe.