Hosseini Fard mentioned factors such as cooler rain and increased relative pistachio shell humidity as a factor in reducing the movement of calcium in the plant and said: the supply of calcium in pistachio fruit is done by transpiration of the plant and calcium is directed from the leaf to the fruit. . In most cases, calcium is present in the leaves, but the fruit turns black. The reason for this complication is that during the formation of bony skin, the fruit has a high need for this element but is not able to absorb it from the leaves. "Research shows that heavy irrigation increases the risk of bone formation," he said. In response to the question why this complication did not exist in the past, Hosseini Fard pointed out: in order for the plant to absorb calcium, this element must be present in the soil. The results of research have shown that as the age of the gardens increases, the percentage of calcium sulfate (gypsum) in the soil decreases, because over time and over the years, this gypsum dissolves in irrigation water and from the soil profile. going out.
