Effect of Nitrogen and Weed Interference on Some Agronomic Traits, Five Cultivars Wheat Yield and Yield Components

Cultural weed management is an important strategy in sustainable agriculture. This experiment was conducted out to study the effect of nitrogen rates on compatibility of five wheat cultivars with weed in 2011 at university of Mohaghegh Ardabili. The experiment was loaded as factorial strip plat at randomize complete block at three replications. The factors were three nitrogen rates (0, 75 and 150 kgN/ha), five wheat cultivars (Azar2, CaskoZhen, Sayson, MV17 and Gaspard) and weeds interference at two levels (with and without weeds). Results showed that nitrogen rates had a significant effect on the percentage of light penetration, wheat height, wheat grand cover and grain yield. Application of 150 kg N ha-1 reduced the percentage of light penetration to two times. Weed interference reduced wheat cover to two times too. Results showed that weed interference reduced grain yield over 50%. Nitrogen rates had a different effect on grain yield of wheat cultivars.