Effect of chemical weed-control methods on productivity of transplanted rice (Oryza sativa)

A field experiment was conducted during the rainy seasons of 2000 and 2001 on transplanted rice (Oryza sativa L.) at Chiplima, Orissa, to evaluate the efficiency of different herbicides and herbicide mixtures. Application of almix 0.004 kg tank-mixed with butachlor (1.0 kg/ha) 3 days after transplanting (4.80 t grains/ha) or application of butachlor (1.0 kg) at 3 days after transplanting (DAT) followed by sequential application of almix 0.004 kg/ha at 25 DAT (4.69 t grains/ha) was as good as hand-weeding twice at 20 and 40 DAT (4.84 t grains/ha) in controlling weeds and achieving grain yield. Application of almix 0.004 kg + butachlor 1.0 kg/ha and butachlor 1.0 kg, followed by almix 0.004 kg/ha increased the grain yield by 36.8 and 33.6%, respectively, over the unweeded check. There was a negative linear relationship between weed dry weight and grain yield (r = −0.74).