study of nitrogen split application levels and variety effects on yield and agronomical characteristics of corn

in this research, the effects of split application of nitrogen fertilizer on yield and yield component of three varieties of corn have been investigated. for this purpose, a split plot experiment on the base of randomized complete blocks in four replications was used. the main plots were three varieties of corn (370, 447 and 499), and sub plots were six split application of urea fertilizer treatments. in each treatment 180 kg/ha pure nitrogen (392 kg/ha urea) was used. the results show that there is significant difference in bush height, grain yield, harvest index and number of kernel in ear between varieties and there is no significant difference in weight of 100 grains and bush diameter. variety of 499 was the best one view point of mentioned characteristics. also fertilizer treatments show significant difference. in all characteristics, except of weight of 100, the forth treatment (n4: 98kg urea/ha in planting time, 147kg urea/ha three weeks before flowering, 147kg urea/ha three weeks later flowering) was identified as a best treatment. interaction of variety-fertilizer treatment only has significant effect on grain yield, harvest index and number of kernel in ear. according to obtained results of this research, variety of 499 is preferred for planting because in this variety the highest yield has been achieved. also, the forth fertilizer treatment is suggested among the all treatments.