The effect of weed control period and nitrogen rate on yield and yield components of cowpea

In order to investigate the effect of weeding period and nitrogen rate on yield and yield components of cowpea, a field experiment was conducted in Ahvaz .research farm of shahid salemi in year 2011-12. The main factors include the amount of nitrogen in three levels (55, 85 and 115 kg N ha) and subplots in three levels of weed control (weeding to budding, flowering and weed weeding), respectively. The results showed that weed interference and nitrogen fertilizer significantly increased grain yield and seed yield components. Highest seed treatment with 2.5 tons per hectare and 115 kg nitrogen lowest on treatment 55 kg per hectare to 2 ton per hectare. Number of pods per plant, number of pods per square meter weeding the pod has an average lower than other treatments. The highest yield, with an average of 2.56 tons of weed treatment and the lowest average grain yield was awarded to budding 2.09 to weeding treatments.