Investigation on effects of different application methods of urea fertilizer drilling in planting time, topdressing and foliar spraying on grain yield and quality of different dryland wheat varieties in rain fed conditioný.

In order to study of urea fertilizer effects in planting time, topdressing and foliar spraying on grain yield and quality of different dryland wheat varieties present investigation was conducted in factorial experiment biased on RCBD design with wheat cultivar factor in 2 levels(Zacross and Kohdasht) and urea fertilized in 9 levels such as N0, N40+20, N30+30, N20+40, N60+0, N0+60, N40+F0, N40+F1 and N40+F2 which F0 is zero urea solution, F1 2.5 percent urea solution and F2, 5 percent urea solution applications in three replications in Gachsaran research station for three years (2007-2010). Results of combine analysis showed that urea values management effects, year effect for grain yield and harvest index and year * treatment interaction effect at 1% were significant respectively. Also at year* treatment effect grain yield at 5% level was significant. But effect of treatment, cultivar* treatment, year * treatment * cultivar and year * cultivar were not significant at probability levels. Mean comparison of years effect showed that from among years only the third year with 2307 kg.ha-1 recognized as the best years. Also nitrogen levels N40+20, N40+F2 detected as the higher values and fusing 2 years with 1970, 1923 kg.ha-1 relation to other nitrogen levels have been showing a suitable condition. From between wheat cultivars, Kohdasht cultivar respectively with 1921 and 3822 kg.ha-1 grain and straw yields was better than Zacross cultivar. Also results showed that in the third year, Kohdasht and Zacross cultivars with N40+20 nitrogen values with average 2587 kg.ha-1 grain yield were significant relation to other levels. Generally N40+20 and N40+F2 respectively were detection as the most values. Therefore as if in the different years, year effect was determined as useful factor, then urea application management in the tillering stage will be useful if we had been sufficient rainfall N40+20 nitrogen level will be affect on the grain yield and yield components. Finally we could be recommended that in the tillering stage, with sufficient rainfall, in stead of topdressing urea application we can use N40+F2 urea formula.