Effects of Deficit Irrigation on Yield and Growth of Greenhouse Cucumber

In order to investigate the effects of deficit irrigation on greenhouse grown cucumber, an experiment was performed in randomized complete design with employing of 4 irrigation treatments and 3 replications at the Agricultural and Natural Resources Research Center of Yazd, Iran. Irrigation with restoring 100% of the soil moisture depletion at each water application as the first treatment (T1), restoring its 80% at the second treatment (T2), and 60% and 40% at the third (T3) and fourth (T4) treatments, respectively, were considered. The amount of water used in each growth stage was effective on yield. The results showed that there was a direct relation between the amount of irrigation water and yield. Variance analysis of the results showed that the effects of irrigation treatments on growth and yield were significant. The more the volume of irrigation water decreased, the more the yield, water use efficiency, plant height, leaf area and soil water EC decreased, while the chlorophyll amount increased. Maximum water use efficiency, 69.7 kg m -3 , was recorded in T1. According to the results, deficit irrigation may not be recommended because of significant reduction in yield due to cucumber sensitivity to water deficit. Saving in water, however, due to efficiency improvement is possible. The results showed that, the amount of water consumption in irrigation system of Yazd greenhouses is about 55- 60% higher than water requirement of the cucumber plants. For sever water shortage in the region, application of deficit irrigation after the crop yield stage to minimize the yield reduction is recommended or other deficit irrigation methods may be employed for this purpose.