Effect of planting date and final irrigation on cotton yield at Garmsar condition

To determine the best planting date and irrigation schedule in a cotton field (Gossypium hirsutum var. Varamin) in Garmsar region an experiment was conducted in 2011. The experimental design was split plot based on randomized complete block with three replications. Three irrigation termination dates (2011 Sep 11th، 2011 Sep 21st and 2011 Oct 2nd) arranged in main plots as main factor and three planting dates (2011 May 10th، 2011 May 25th and 2011 Jun 9th) located in sub plots. During the growth season، phonological events such as germination، date of flowering، date of boll formation، boll opening، maturity and after harvest attributes such as plant tall، number of boll per plant and weight of boll were recorded. The result showed that effect of planting date on seed cotton yield، plant/m2، boll per plant and plants height was significant but boll weight was not affected significantly by this treatment. First planting date and first irrigation termination date with 7729 kg/ha of seed cotton yield is the best treatment. Because of stable environmental conditions in years of experiment، the effect of these treatments on studied treatments is not significant. Totally، two first planting dates has the higher yield than third and first date of irrigation termination is the best because of decreasing the number of irrigation.