College Farm, Andhra Pradesh Agricultural University, Hyderabad-500 030
Haryana Agricultural University, Hissar
1Contribution from the thesis submitted by N. Gopal Naidu to the G.B. Pant University of Agril. & Tech., Pantnagar in partial fulfilment of M.Sc. (Ag.) programme in 1976.
A field experiment was conducted during Kharif 1975 at the Crop Research Centre of G.B. Pant University of Agriculture and Technology, Panthnagar, District Nainital. The object of the experiment was to find out the effect of different groups of weeds and weed free periods on the yield of drilled rice. The results indicated that the maximum yield of 57.79 q/ha was recorded when the plot was kept free of weeds for the first 45 days after sowing where as it was only 19.86 q/ha when the plots were kept weed free for zero days (no weeding). The increase in grain yield of 64, 130 and 190 per cent was observed with the increase in weed free periods upto 15, 30 and 45 days after sowing respectively as compared to no weeding. Grain yield was significantly influenced when the crop was grown in association with grassy or grassy 4- broad leaved weeds. Broad leaved weeds did not influence the grain yield significantly at different periods of weed free maintenance. Echinochloa crusgalli was a major grassy weed found in the experimental plots.
