Contribution from Department of Agronomy, Himachal Pradesh Krishi Vishvavidyalaya, Palampur - 176062.
Two hand weeding or application of thiobencarb 1.5 kg/ha produced same yield in both wet and semi-wet cultures and response to N was signifieant upto 150 kg/ha. In unweeded plots, response to N was significant only in wet cnlture. Under low weed infestation, there was no significant difference in yield due to rice cultures, but response to N was significant up to 100 kg/ha in weeded plots and up to 50 kg/ha in unweeded plots. Under higher inherent weed infestation, profitable dose of N as well as response/kg N was higher than where weed problem was less. Benefit/cost ratio of weed management was about 3 times the N application.
