Effect of micro-herbicides on weed dynamics, yield and economics of transplanted rice (Oryza sativa)

The efficacy of some potent micro-herbicides in conjunction with other herbicide for control of various weed flora in transplanted rice (Oryza sativa L.) was studied during the rainy season of 2001 and 2002 at Varanasi, Uttar Pradesh. The major weedS found were Echinochloa colonumL., Echinochloa cruss galli Beauv., Cyperus rotundus L., Cyperus difformis L., Fimbristylis millacea (L.) Vahl and Ludwigia parviflora Roxb. Almix + 2, 4-DEE (15 + 500 g/ha) applied 8 days after transplanting was found most effective in controlling weeds and maximizing rice grain yield (58.3 q/ha). This was on a par with hand-weeding done thrice at 20,40 and 60 days stage. This treatment recorded highest net return (Rs 46,392) and benefit: cost ratio (3.9). Hand-weeding treatments though significantly reduced the weed biomass and improved the grain yield, owing to higher labour cost reduced the benefit: cost ratio.