كارآيي مصرف آب گندم تحت شرايط شوري و كم آبي

Water Use Efficiency of Wheat Under Salinity and Water Stress Conditions

Water scarcity and low quality of soil and water resources are factors causing production loss in arid and semi arid regions. In this condition, the application of deficit irrigation and use of saline drainage water are the most important alternatives for decreasing detrimental effects arising from water shortage. For this purpose, this research was conducted to evaluate yield and water use efficiency (WUE) of wheat under salinity and water stress conditions for two growing seasons (2001-2002) in north of Gorgan. The treatments were consisted four levels of irrigation water 50 (W1), 75 (W2), 100 (W3) and 125 (W4) percent of crop water requirement and with four irrigation water salinity levels of 1.5 (S,), 8.5 (S2), 11.5 (S3) and 14.2 (S4) dS/m. The experiment was performed using to a randomized complete block design with split plot layout, which considered water quantity as main plot and water quality as subplot with three replications. The results revealed that wheat yield and WUE did not considerably decrease when some drainage saline water was mixed with non-saline irrigation water and it was found the use of such water completely impossible for irrigation purposes. The soil salinity at the harvest time was increased comparing with beginning of the season as a result of using saline water. In S4 treatment, soil salinity (ECe of surface 0-40 Cm soil) was increased from 4 dSlm at the planting date to 7.5 dSlm at the harvesting time. However, it decreased again by the next pre-sowing stage due to autumn rainfall.