The effect nitrogen application rate and wild oat density on yield and yield components of wheat cultivar Yavaros

In order to study the effect of different rates of nitrogen and different densities of wild oat on yield and yield components of wheat cultivar Yavaros، an experiment was conducted in 2007-2008 growing season in Mehran. The experimental design was a split plot based on randomized complete blocks with three replications. The main plots were four levels of nitrogen (80، 120، 160 and 220 kg/ha)، and subplots were wild oat densities (0، 25، 50 and 75 plant/m2). The results showed that yield and yield components were significantly affected by different levels of nitrogen and different densities of wild oat. Interaction effects of different rates of nitrogen and different densities of wild oat were significant except 1000 seed weight. Increasing levels of nitrogen rate from 80 to 120 kg/ha increased grain yield، but excessive levels of nitrogen، reduced the grain yield. In higher densities of the wild oat increasing excessive nitrogen application did not decrease the negative effects of weed infestation on yield and yield components. The lowest grain yield (4477kg/ha) being obtained at interaction at 75 plant/m2 wild oat and 80 nitrogen rates kg/ha.