The Importance of Applying Moisture Retaining Compounds in Pistachio Seedling Growth Medium under Drought Stress

Introduction: Water scarcity is one of the most serious threats to the sharp decline of yield in different cultivars of pistachio in Iranian orchards. Therefore, attention should be paid to the maximum productivity of water resources and the use of modern agricultural methods to increase water use efficiency. Materials and Methods: The purpose of this study was to evaluate the effects of perlite (0 and 10 g kg-1soil), humic acid (0, 7.5 and 15 g kg-1 soil) and irrigation interval (7, 20 and 30 days) on growth parameters of pistachio seedlings. This research was based on a completely randomized factorial design on "Badami Zarand" rootstock under greenhouse conditions. The studied factors included plant height, root length, leaf area, fresh and dry weights of root and shoot and uptake of nutrient elements in leaves. Finally, the statistical analysis of the data was done through a three way factorial ANOVA using the SPSS software, and the means of the data were compared using Duncan’s method. Results: The results of the study indicate that the application of humic acidin the concentration of15 g kg-1 soil and perlite 10 g kg-1 soil have a significant effect on plant growth and nutrient uptake under drought stress, which is associated with increasing effective roots and water abundance. Conclusion: The results of the interaction effects showed that the application of humic acid and perlite can efficiently reduce the negative effects of drought stress on pistachio seedlings during irrigation intervals of 30 days, and it also causes more tolerance to stress.