عبادالله بانیانی
محمد یوسف ناصری
داود غفاری توران
محمدحسین میرزایی
احمد دیلم تجری

In order to find out the effects of management of nitrogen application on sust~inable cotton production, an experiment was conducted in 2004 ins silty clay loam soil at Varamin research center for two years and at Hashem Abad Cotton Research Station for one year. The experimental design was factorial in Varamin and Split, Split Plot with Randomized Complete Block in Hashem Abad wth four and and three replications. The treatments included: three times of fertilizer application, at squaring, flowering and boil formation stage and four level of fertilizer application ( 0, 50% less than recommended rate, 100% and 150% of recommended rate) and two applying methods' broad casting and banding application methods. soil samples were collected and analyzed. The results in Varamin showed that the treatments had not effected the boil weight, but the check had the lease boil weight. The level of fertilizer application had a significant effect on number of boil per plant at 1% level. The highest number of boil was achieved when the 100% recommended rate was used at flowering stage. Also banding method with 100% recommended rate of fertilizer showed the highest yield. As the rate of fertilizer and times of application increased the rate of vegetative growth increased and earliness delayed. According to the results of Gorgan, the effects of using time on number of monopodial branches and earliness were significant at 5% and 1 % levels, respectively. The rest treatments in this study had no significant effects on different properties. Key words: cotton, nitrogen fertilizer, application methods, application time

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