Effect of fertilizer and butachlor on weeds and yield of transplanted rice (Oryza sativa)

Abstract

A field experiment was conducted during rainy season of 1988 and 1989 at Jorhat, to study the effect of different doses of fertilizer and methods of butachlor application on weeds and transplanted rice (Oryza sativa L.) under standing water condition. Better crop growth owing to application of 40 kg N, 20 kg P,O, and 20 kg &Oha suppressed the growth of weeds considerably. This recorded 36.9 q grain yieldha. Among the butachlor application methods, sand-mix controlled the weeds most effectively and accrued in significantly higher crop yield (40.28 qha) than to other methods. Rice cultivar Mahsuri (40.75 qha) significantly outyielded the traditional one Badshabhog (27.48 qha). -- Reduction in rice yield due to weeds able P2O5 16.9 kglha and available &O 45.0 ranges from 9 to 5 1% (Mani et al., 1968). kgha. The experiment comprised 3 fertilizer The growth of both weed and rice (Oryza doses, 2 cultivars and 3 butachlor applica- sativa L.), specially the crop depends greatly tion methods (Table I), tested in split-plot on the amount of applied nutrients. Better design with 3 replications. The cuhivars and nutrient supply leads to better crop growth fertilizer doses in combination were as- which in turn suppresses weeds. Several her- signed to main plots and butachlor applica- bicides including butachlor proved most tion methods to subplots. Thirty-five-day- successful against weeds of transplanted rice old seedlings were transplanted during the (Mishra and Singh, 1989; Pandey and Sukla, second week of July maintaining 25 cm x 20 1990). However, its efficacy under standing- cm spacing. Fertilizers were applied in 3 3 water condition is effected due to different splits. Half of N and entire quantity of P,05 methods of application. Therefore the and K,O were applied at the time of final present investigation was carried out to puddling. Remaining part of N was applied study the effect of various doses of fertilizer in 2 equal splits at tillering and panicle-ini- and methods of butachlor application on tiation stages. Butachlor @ 1.5 kgfha was weeds and transplanted rice under standing- applied 4 days after transplanting @AT) on water condition. standing water. Observations on weeds were made at 70 DAT.