Copper is present in the structure of three types of proteins and activates several enzymes. Copper ions are binding and adsorbable only in the form of complexes with other compounds and exchangeable with organic matter. In case of copper deficiency in plants and trees, the leaves of plants remain small and the young branches of trees suffer from leaf burn. In environments with alkaline pH (calcareous and alkaline soils), copper is generally not absorbed by plants. Therefore, due to the fact that most of the soils of Iran are alkaline and calcareous, the efficiency of copper uptake in Iranian soils is very low. This element is essential in oxidase-catalase enzyme systems and is involved in electron transfer reactions and activates several enzymes. Copper is not mobile in the plant and will remain in the form of sediment in the soil. Therefore, to increase the uptake of copper by plants, the pH of alkaline and calcareous soils must be adjusted. One of the effective methods of improving calcareous soils is the use of ammonium sulfate. Using ammonium sulfate fertilizer, in addition to providing nitrogen and sulfur required by plants and trees, alkaline soils can be modified and its pH can be reduced.
To get acquainted with the use of copper in agriculture, it should be noted that if the soil is deficient in copper or for some reason the efficiency of copper uptake from the soil is low, plants will suffer from copper deficiency. In copper-deficient plants, the leaves become twisted and the petiole bends downward. Copper deficiency can be expressed by mild general chlorosis with a lack of permanent trigger pressure on young leaves. Newly grown leaves become reticulate and their veins are green, with white to grayish-white areas. On some leaves, chlorotic hollow spots are observed and tend to bend downwards. The leaves are small and chlorotic with necrotic spots.
Copper deficiency often occurs in summer and generally in sandy soils irrigated with fresh water. The phenomenon of copper deficiency in pistachio trees, newly fertilized trees or newly established orchards may also be observed.
For example, in pistachio trees, the symptoms of copper deficiency are as follows:
Pistachio kernel deformity
Pistachio trees wither and the tip of immature and new leaves at the end of the branch burns, as well as fallen leaves
Tree twigs and darkening of tree bark
Wrinkling of the branches and the appearance of small dark spots around the tip of the branch
Copper sulfate can be used to compensate for copper deficiency in various trees and to meet the trees’ need for this nutrient. In addition to providing the copper needed by trees, copper sulfate has other uses
