afsaneh shool

The annual consumption of soil potassium by pistachio trees is high. Since the clay soil absorbs potassium, the amount of potassium that can be exchanged or used by the tree in the soil solution is little, and every year this deficiency must be compensated by fertilizers. To evaluate the role of potassium in improving the nutritional elements of the leaves and nuts of two pistachio cultivars (‘Ahmad-Aghaei’ and ‘Kalleh-Qoochi’), four levels of potassium fertilizer were used (0, 200, 300 and 400 mg of potassium per liter of irrigation water) in a factorial experiment in the form of a randomized complete block design with three replications. This experiment was performed on the ON and OFF branches in 2017 and 2018. The results showed that the application of potassium increased the amounts of nutritional elements in the leaf and nut. Specifically, the amounts of nitrogen, phosphorus and potassium were higher in the leaves of OFF branches, whereas the concentrations of calcium and magnesium were higher in the leaves of the ON branches. In both cultivars, the application of potassium increased the amounts of nitrogen and phosphorus in the leaf, as well as the potassium content in the nut. The amounts of calcium and magnesium in the leaf and the amount of calcium in the nuts were higher in the Kalleh-Qoochi cultivar. This treatment can be recommended when plants are in their OFF year, so that potassium can be reserve into the tissues until the ON year.

Inorder to investigate the role of potassium in quantitative and qualitative characteristics of pistachios cultivars "Ahmad Aghaei" and "Kaleghoochi", an orchard experiment in the form of a randomized complete block designwith three replications and three factors, cultivar (Ahmad Aghaei and Kaleghoochi), different levels of potassium fertilizer (0, 200, 300 and 400 mg of potassium per liter of irrigation water) and year (2017 and 2018) was done. The results showed that the nut potassium content and the fresh weight of the fruit with the hull increased in the second year of the experiment. Fresh weight of the fruit with the hull, nut length and kernel length were higher in Kaleghoochi cultivar than Ahmad Aghaei cultivar. While the percentage of half kernel and nut width was higher in Ahmad Aghaei cultivar. With the application of potassium, the fresh weight of fruit with hull and without hull, fresh weight of kernel, nut length and width and width, thickness of kernel and leaf potassium increased. In Kaleghoochi cultivar, compared to Ahmad Aghaei cultivar, fresh fruit without skin and kernel, nut thickness and width and thickness of kernel increased in both years. Potassium application in both years increased nut thickness and kernel length and significantly reduced half kernel percentage and deformity. The amount of nut potassium in both cultivars increased with the application of potassium.In the first year and in both cultivars Ahmad Aghaei and Kaleghoochi the use of potassium had a significant effect on reducing regular and irregular early splitting.

In order to investigate the symbiotic effect of arbuscular mycorrhizae (Glomus mosseae) and a bacteria (Pseudomonas fluorescence) on vegetative growth of pistachio seedlings (Pistacia vera cv. Qazvini) under drougth stress، a greenhouse experiment was conducted using four drougth stress levels (100% FC as control، 75، 50 and 25% FC) and four levels of biofertilizers (non mycorrhizal and non bacterial plants as control، mycorrhizal treatment، bacterial treatment and a mixed treatment of both). In the experiment، application of bacteria in different drougth stress levels could not affect root colonization with mycorrhizae whereas increase in root colonization percentage was observed along with increase in drougth intensity. The highest values of leaf area and number، stem height and dry weight of leaf and stem were obtained with 50% FC in comparison with control. Root lenght was increased with increase in drougth stress levels. Dry weight of stem، root length and leaf area were more in mycorrhizal and mixed treatments in comparison with control. The least values of leaf area and number، stem diameter، root length and stem dry weight were observed in bacterial treatment in comparison with control. Root volume and dry weight were maximum in bacterial treatment with a significant difference with control. Totally، it can be concluded that the mixed treatment had the most effect on vegetative growth of pistachio seedling under different drougth stress levels and from drought point of view، 50% FC was the best treatment which improved the most vegetative growth parameters.