Effects of different amount of N-fertilizer and irrigation water on yield and yield components of cotton

In order toinvestigation the effect of different amount of N-fertilizer and irrigation water on cotton yield of Varamin variety, an experiment was conducted in Kashmar agriculture and natural resource station in a Silty loam textured soil with EC=2.2 dS/m and pH=7.8. Experimental design was split plot as randomized complete block design with three replications which three levels of irrigation water including 45, 60 and 75 % cumulative evaporation of class A pan were as main plots and five levels of nitrogen including 0, 60, 120, 180 and 240 kg N/ha were as sub plots. Results showed that the effect of Nitrogen treatment on cotton yield, boll number, side branch number, and plant height was significant while N effect was not significant on boll weight. Irrigation treatments had significant effect on cotton yield. The highest cotton yield, boll number, side branch number, and plant height was obtained from 180 kg N/ha treatment and irrigation at 75 % evaporation from class A pan. By reducing of irrigation water, N-use efficiency decreased as well. In general results of this experiment showed that the best treatment was irrigation with 75 % evaporation from class A pan and 180 kg N/ha.