واکنش علف‌هرز سوروف به سطوح مختلف کود نیتروژن در رقابت با برنج

To evaluate the response of various densities of barnyardgrass to nitrogen levels in competition with Hashemi cultivar of rice an out door pot experiment was conducted in faculty of Agricultural Sciences, University of Guilan in 2012. This experiment was conducted as factorial basis of completely randomized block design with 4 replication. First factor was densities of barnyardgrass (0, 1, 2, 3 and 4 plants per pot) and the second factor was the urea source of nitrogen levels (0, 45, 90 and 135 kg.ha-1). The results indicated that the interaction of barnyardgrass densities on nitrogen levels had only a significant effect on barnyardgrass grains per panicle. The highest number of seed per panicle of barnyardgrass was observed in pots with one barnyardgrass and 135 kg(N). Ha-1. Simple effect of barnyardgrass densites and levels of nitrogen on number of fertile tillers per plant and biological yield were significant. The highest biological yield and fertile tillers was earned in pots having only one barnyardgrass plant, which were fertilized with 90 and 135 kg(N). Ha-1