Overcoming the Unavalablity of Phosphorous in High Soil pH by Phosphorous Foliar Spraying in Pistachio (Pistacia vera L.) cv. Kalleh-Ghoochi

Pistachio (Pistacia veraL.) is an important crop in Iran and has a special position in the country’s exportation. High soil pH causes phosphorus fixation in the soil and does not allow the plant to absorb it. The study investigated phosphorous foliar spraying treatment on pistachio in different types of fertilizers (lekofos, acid phosphoric, urea phosphate, mono potassium phosphate and water (control)) during three times (completion of the growth of endocarp, completion of the development of the embryo and the digestion of endosperm and in the both of this two stages) in a commercial orchard in Sabzewar-Mashhad in 2015. In this research, splitting (%), blankness (%), ounce nut weight, chlorophyll and phosphorous content of leaf were examined. The highest percentage of splitting observed in potassium phosphate and urea phosphate treatments and the lowest percentage observed in the control treatment. There was not significant difference in the chlorophyll content and nut blankness in the treatments compared to control. The analysis of leaf phosphorous indicated a significant difference that urea phosphate treatment in third stage was the highest in comparison to control. Furthermore, ounce nut weight of mono potassium phosphate treatment was highest in the third stage of foliar spraying and it was the lowest in the control.