عنوان مقاله [English]
Since the starting time of cotton irrigation has a considerable effect on the net income of cotton ‘s farmers, therefore, this research was conducted in Hashem- Abad Cotton Research Station, during 2007-2011 years, on Golestan variety and six initial irrigation treatments including: one week before the start of squaring stage (I1), early squaring stage (I2), early flowering (I3 ), one week after flowering (I4), two weeks after flowering (I5) and irrigation three weeks after flowering (I6) in a randomized complete block design with three replications. Sowing was done with the seed planter. The amount of irrigation water was calculated based on the soil moisture defficit. Other agricultural operations including Weed control, thinning and pest control were done under the supervision of experts.Three plants were randomly selected from each treatment and yield components were recorded on them. Results showed that the effect of initial irrigation treatments on yield, earliness, boll weight and lint perecentage was significant at the level of one percent, So that, by delay in starting irrigation, these parameters were decreased. The highest seed cotton yield, with 3951 kg/ha and 3594 kg/ha was obtained in I2 and I1 treatment, respectively. But in terms of water use efficiency, it is recommended to start irrigation at one week after flowering stage.