Evaluation of Rate and Method of Nitrogen Application at Early Bloom Stage on Cotton.

Nitrogen Fertilization management is an important issue in cotton production systems. It is more difficult to balance demand and supply of cotton plant N nutrition compared with other nutrient fertilizers because of the complexity of N cycling in the soil and the indeterminate growth habit of cotton. The experimental design was a randomized complete block with a factorial treatment arrangement and four replications. The N rates (N source included sulfur-coated urea) were included 56, 112, 168, and 224 kg N ha^-1, and methods of N application were included broadcast and banding. Cotton cultivar was Varamin and grown under irrigated conditions at a population of 62 500 plants ha^-1. Plant height, nodes number of main stem, branch number, boll number, dry matter yield, and lint yield averages were higher in banding method than broadcast method. The 112 kg N ha^-1 produced the highest plant height, branch number, boll number, dry matter yield, and lint yield in broadcast method. Nodes number of main stem average increased from 56 to 112 kg N ha^-1 and decreasing from 112 to 224 kg N ha^-1 in broadcast method by increasing N rate. Branch number, boll number, dry matter yield, and lint yield averages decreased from 56 to 168 kg N ha^-1 and increased from 168 to 224 kg N ha^-1 in banding method by increasing N rate. Plant height, nodes number of main stem averages increased from 56 to 112 kg N ha^-1 and decreasing from 112 to 224 kg N ha^-1 in banding method by increasing N rate.