Abstract

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh between December 2013 to May 2014. The purpose of the experiment was to investigate the combined effect of herbicides on the weed management of rice. The experiment consisted of two varieties, BR 14 (Gazi) and BRRI dhan 28 along with nine different weed management treatments such as weedy check, the recommended dose of Manage 10 WP, recommended dose of Polifit 500 EC, 70% of Manage+20% of Polifit, 20% of Manage+70% of Polifit, 60% of Manage+20% of Polifit, 20% of Manage+60% of Polifit, 50% of Manage+20% of Polifit and 20% of Manage+50% of Polifit. Twelve weed species belonging to five families infested the experimental plots. In the BR14 Variety at 20, 40 and 60 days after transplanting (DAT), lower weed population/m2 and weed dry weight (g/m2), but higher weed control efficiencies of 65.52, 60.35 and 66.98% were realized, respectively. The recommended dose of Polifit 500 EC treatment resulted in the lowest weed population and weed dry weight as well as the highest weed control efficiency of 83.45, 84.93 and 87.07% at 20, 40 and 60 DAT, respectively. Therefore, to control weeds in an effective manner and in order to get the optimum grain yield in boro rice, an application of Polifit 500 EC should be applied.