Palm response to the implementation of surface and subsurface drip irrigation system

Water restriction is one of the most important factors inhibiting the crop production. Accordingly, application of pressurized irrigation systems to optimize utilization of water resources is inevitable. This study was conducted in Behbahan Agricultural Research Station during three cropping seasons (2013-2016) and based on a randomized complete block design with a split plot and three replications. The main plots were consisted of Subsurface Drip Irrigation (SDI) system that applied irrigation water at three levels of 75, 100 and 125% of water requirement and a surface Drip Irrigation (DI) system with application of 100% water requirement. The sub-plots were consisted of two varieties of date palm; Khasi and Zahedi. The crop water requirement was estimated based on Penman-Montheith method and using a daily weather information data collected from Behbahan weather station. Analysis of variance showed a significant difference (5%) between water use efficiency of different levels of irrigation water. As, the SDI system with 75% irrigation level showed the highest water use efficiency to be 0.698 kg/m3. The comparison of interaction effects showed that the water use efficiency of Zahedi dates in 75% SDI system with 0.744 kg/m3 is higher than that of Khasi dates. In the other hand, the 75% SDI system saved 2509.6, 5019.2 and 2630.3 m3/ha irrigation water as compared with 100% and 125% SDI and 100% DI systems, respectively. According to the results, the interaction impact of irrigation levels and varieties on water use efficiency was significant but the interaction of irrigation systems and varieties were not significant. The stiffness of fruits was measured to be 11.3 lb per square meter in 75% SDI system which was the highest as compared to those for other treatments. The results of this study showed that the SDI system could be used for palms trees without restriction while use less water without significant impact on yield.