ECONOMIC CULTIVATION OF TRANSPLANT AMAN RICE UNDER DIFFERENT WEED MANAGEMENT TECHNIQUES AND PLANT SPACING

Abstract

An experiment was carried out at the Agronomy field. Sher-e-Bangia Agricultural University. Dhaka during the period from July to December. 2006 to evaluate the economic cultivation of transplant arnan rice under different weed management techniques and plant spacing. The experiment comprised six weeding treatments viz, no weeding. two hand weeding at IS and 40 days after transplanting (DAT). one weeding with BRRI push weeder at IS DAT + one hand weeding at 40 DAT. pre-emergence application of M.Chlor 5G (Butachlor) at 5 DAT + one hand weeding at 40 DAT, pre-emergence application of Oxastar 25 EC (Oxadiazon) at 5 DAT + one hand weeding at 40 DAT. pre- emergence application of Rifit 500EC (Pretilachlor) at 5 DAT + one hand weeding at 40 DAT and three plant spacings viz. 20cm x l Ocrn, 25cm x 15cm and 30cm x 20cm. Twelve weed species belonging to seven families were found in the experimental field of which Sphenoc/ea zeylanica. Eclipta alba and Ludwigia octovalvis were the most dominating weed species in transplanted aman rice. The overall performance of use of Pretilachlor at the spacing of 25cm x 15cm was found to be the best and it produced the highest grain yield (3.87 t ha"), highest net profit (23847.00 Tk ha") and highest BCR (1.79) that followed by BRRI push weeder + one hand weeding at the spacing of 30cm x 20cm.