Effect of mycorrhiza and humic acid application on physiological traits, yield and water use efficiency of cotton under water deficit stress conditions

In order to evaluate the effect of irrigation, humic acid and mycorrhiza application on physiological traits, yield and water use efficiency (WUE) of cotton, an experiment was carried out as a factorial split-plot based on a randomized complete block design with three replications in the research farm of Islamic Azad University of Birjand, Iran in 2016. Three irrigation levels (40, 70 and 100 percent of water requirement or PWR) were as the main plot and the combination of two mycorrhiza levels (non- application and application) and two humic acid levels (0 and 10 L. ha-1) were considered as sub-plot. The results showed that mycorrhiza application in conditions of supplying 100 and 70 PWR for the plant significantly increased the chlorophyll index, stomatal conductance, number of boll per m2 and yields of cotton, but the highest increase in these traits was observed in conditions of supplying 70 PWR. Also, the highest WUE in 70 PWR and application of mycorrhiza treatment was obtained.Generally, mycorrhiza application more effectively than the application of humic acid improved physiological traits, yield and WUE of cotton.The results showed that considering the WUE and economic yield of cotton, supplying 70 PWR and mycorrhiza application for this plant in Birjand can be considered.