Evaluation of Rate and Method of Nitrogen Application at First True-Leaf 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 broadcast method than banding method. Nodes number of main stem, and lint yield averages were increased by the addition of N rate in broadcast method. Branch number, boll number, and dry matter yield averages decreased from 56 to 112 kg N ha^-1 and increased from 112 to 224 kg N ha^-1 in broadcast method by increasing N rate. The 168 kg N ha^-1 produced the highest plant height in broadcast method. Plant height average increased from 56 to 112 kg N ha^-1 and decreased from 112 to 224 kg N ha^-1 in banding method by increasing N rate. The 112 kg N ha^-1 produced the highest branch number, boll number, dry matter yield, and lint yield in banding method. The higher rate (224 kg N ha-1) had the highest nodes number of main stem in banding method.