Abraham varugheseNair, K P MKAU2019-07-262019-07-261980Agricultural Research Journal of Kerala, 18(1), 1-7.http://krishikosh.egranth.ac.in/handle/1/5810117150In studies on the critical periods of crop-weed competition a in short duration rice variety 'Triveni,' carried out at the College of Agriculture, Vellayani, during the second crop season of 1976-77, it was found that the critical period of crop-weed competition lies between 21 and 40 days after transplanting. During i his period, the weed emergence and dry matter accumulation were maximum. At least a weed free condition of 21 -30 days in the critical period of 21-40 days, is essential to obtain good yields.ennullArticle