Comparison of Growth and Yield Performance of Mature Pistachio Trees in the Transition from Surface Irrigation to Drip Irrigation in Saveh

More than 90 percent of Iranian pistachio orchards are irrigated using surface methods, thus, changing or improvement of irrigation systems is necessary considering the declining water resources. The present research was carried out to investigation the effect of changing irrigation system from surface to drip on mature pistachio orchards (cultivar Ahmad Aghaei) in 2013 and 2014 in Zarandiye region of Saveh, Iran. The experiment was performed as factorial in a completely randomized block design (CRBD) with irrigation methods (surface and drip irrigation) and years of the experiment implementation as the second level variable, in three replications. Some quantitative and qualitative parameters of pistachio yield as well as growth of annual branch and water use efficiency were measured during the experiment. The results showed that irrigation system change of mature pistachio trees from surface to drip was possible. Irrigation system change was significant in dry yield, number of seed in ounce, percent of blankness, growth of annual branch, leaf area, and the 100 seed weight of pistachio at P ≤ 0.05. In the first year experiment, a reduction in performance and quality of yield was observed in drip irrigation compared to surface irrigation, but, in the second year, enhancing of performance and improvement in quality of pistachio in drip irrigation in comparison to surface irrigation showed adaptability of pistachio trees to change of irrigation system. The 2-year means of dry yield, water consumption, and the amount of water use efficiency in surface and drip methods were obtained at 739 and 927 kg per ha, 6375 and 4110 m3 per ha, and 125 and 190 g of dry yield per m3 of water, respectively. Because of alternative bearing, it is recommended to perform these tests for four successive years, so that the results would be more reliable for recommendation purposes.