Investigation of Ni and Urea Interaction on Vegetative Characteristics, Urease Activity and some Nutrient Elements of Two Pistachio Rootstocks: ʻBadamai-Riz Zarandʼ and ʻQazviniʼ

According to recommendation and utilization of urea pistachio orchard as drench, or foliar application in, this study was done to evaluate the interaction of urea and Ni on urea absorption and efficiency of and vegetative growth of pistachio. To this purpose, a greenhouse factorial experiment was conducted with three factors, including nickel sulfate at three levels (0, 150, and 300 mg l-1), urea at two levels (0 and 2 g l-1), and two Rootstock (Badami-Rize-Zarand and Qazvini) and four replications. Using completely randomized design. Treatments were applied on pistachio seedlings as foliar application during three stages with two week-intervals when seedling had 8-10 leaves. The results showed that foliar application of nickel sulfate and urea in three stages increased vegetative growth parameters (seedlings height, stem diameter, leaf area, fresh and dry weight of leaf and root and leaves Fe, Zn, Ni and N contents, significantly. Based on the results of this study, urea foliar application resulted in an increase in urea content of leaf, but application of nickel sulfate resulted in significant decrease of it. It seems that application of nickel sulfate increased activity of urease enzyme. In overall that simultaneous foliar application of nickel and urea can increase urea fertilizer efficiency.