The amount of zinc in the soil solution is very small and the higher the pH pistachio shell of the soil, the lower the amount of zinc that can be absorbed by the plant, so in soils with alkaline pH, which is specific to calcareous soils, zinc deficiency is common and widespread. Excessive use of phosphorus fertilizers in soils with low usable zinc content. Causes zinc deficiency in the plant. Zinc has a catalytic or structural role in many plant enzyme systems and is also involved in the production and breakdown of proteins in plants. One of the most prominent roles of zinc in the production of the amino acid tryptophan is as a prerequisite for the production of the hormone auxin, which is effective in the longitudinal growth of branches. Zinc also plays a major role in the pollination and germination stages of pollen grains and accelerates the growth of pollen tubes and thus increases the possibility of fertilization and fruit formation.
Symptoms of zinc deficiency in pistachio trees
Symptoms of zinc deficiency include delays in the growth of vegetative and regenerative buds, even for up to a month, formation of smaller, redder seeds than healthy seeds, fine-grained, short-leafed, shrinkage between twigs and rosettes. The critical limit of zinc in soil is 2 parts per million (PPM) and in pistachio leaves is 30 parts per million (PPM). It is recommended after harvest and in late March when the buds swell and in May in pistachio orchards.