The effect of surface midseason drainage on growth, physiological indices and grain yield of rice variety Tarom-Hashemi

Proper water management in the paddy fields has an important role in the efficacy of other production inputs in rice cultivation. One of the important parts of paddy water management is midseason drainage. To investigate the influence of surface mid-season drainage on growth and yield of rice cultivar Tarom-Hashemi، a field experiment was carried out in randomized complete block design with six treatments and three replications in Haraz Promotion and Technology Development Center in 2013 growing season. The experimental treatments were continuous drainage of zero (control)، 5، 7، 9، 11 and 13 days and their effect was evaluated on plant height، number of tillers، panicle length، grain filling percentage، harvest index، dry weight، leaf area index، crop growth rate، net assimilation rate and grain yield. Statistical analysis showed that the effect of midseason surface drainage on dry matter was significant and there were no significant difference for other studied characteristics in compared with control treatment. Application of midseason drainage increased the crop growth rate and net assimilation rate than control treatment. Increasing midseason drainage duration to 13 day caused in decreasing grain yield as 13% with compared to control treatment. Therefore، in drought condition and due to midseason drainage benefits، duration of midseason drainage could be increased to 13-day without not-significant decreasing in grain yield.