Effect of planting date and nitrogen fertilizer on grain sorghum yield and yield components

Effect of planting date and nitrogen fertilizer on yield and yield components of grain sorghum was investigated. The experiment was carried out in a split plot based on a randomized complete block design with three replications with four levels of nitrogen fertilizer including 0, 100, 150 and 200 kg.ha-1 as the main factor and planting dates including May 30, 15 and 30 June as sub plots. Nitrogen fertilizer significantly increased the yield (6.078 t.ha-1) and with consumption of 200 kg.ha-1 nitrogen, yield was increased dramatically. Taking 200 kg. ha-1 fertilizer increased biological yield (20.561 t.ha-1). Effect of nitrogen fertilizer on grain weight (2.414 g) and seed number was significant at 1%. The most effective planting time on the yield and yield components was May 30. The interaction between planting date and nitrogen fertilizer was not significant in any traits. According to the results of this experiment, 200 kg.ha­-1 N can be used to achieve maximum yield at first planting date.