Two field experiments were conducted during kharif of 2009, to optimize ground cover by green manure cover crops before taking no-till direct seeded basmati rice and mechanical transplanted coarse grain rice. The treatments included three cover crops ( Sesbania, mungbean and cowpea) with two seed rates (X and 2X) along with check (without cover crop) under no-till after wheat harvest. The X seed rates for Sesbania, mungbean and cowpea were 30, 20 and 50 kg/ha, respectively. Farmers' field trails on the issue in question were also conducted at three locations. Weed infestation until cover crops were knocked down, was significantly reduced due to growing of cover crops as compared to plots where no cover crop was included. Minimum density and dry weight of weeds was recorded with Sesbania at 60 kg/ha seed rate which was superior to all other treatments. This could be due to ample ground cover and heavy biomass production by Sesbania. In general biomass production among green manure cover crops was followed the sequence of Sesbania > cowpea > mungbean. Due to lower cost of seed, Sesbania at 60 kg/ha was realized more economical than other cover crops. Infestation of Echinochloa sp. in rice was lowest in the plots where Sesbania was taken as preceding cover crop and it was superior to other two cover crops. There was no infestation of sedges in rice in the plots where cover crops were grown but there was infestation of sedges in check plots. There was no significant impact of different cover crops on the yield and yield attributed of rice; however, to attain higher returns, inclusion of green manure cover crops on long-term basis could be more meaningful.
