What is zinc sulfate

What is zinc sulfate?

Zinc is a vital element for the plant, albeit in small size. This metal causes physiological activities in plants which have a significant impact on the processes of glucose formation, photosynthesis, protein synthesis, fertility, growth, and resistance to disease in the plants. If the plant is subject to zinc deficiency, these physiological activities are not performed well, hence significantly decreasing the plant health and fertility and leading to a decrease in the quality of the product and its decline.

Zinc plays a catalytic role in most of the plant enzymes. The presence of zinc is significantly determinative in plant metabolism due to the effect on the activity of hydrogenase and carbonic anhydrase enzymes, stabilization of ribosome structures, and the cytochrome synthesis. In general, plant enzymes activated by zinc are involved in maintaining the integrity of the cell membrane structure, protein synthesis, glucose metabolism, regulation of the auxin hormone synthesis, and the formation of pollen[1].

The regulation of gene expression in plants can significantly strengthen the plant against stress, and the presence of zinc contributes directly to the regulation of gene expression.

Zinc also plays a significant role in the structure of many enzymes associated with plant metabolism. The amount of RNA and ribosomes in the cells decreases significantly due to zinc deficiency. The presence of zinc is essential for the formation of the amino acid tryptophan involved in the production of auxin. If the plant suffers from IAA auxin deficiency due to zinc deficiency, this will lead to a lack of cell wall growth and thus reduced water absorption in the plant. In this way, it can be claimed that zinc regulates the absorption and transfer of water by the plant, in addition to regulating the destructive rates of short-term stresses and heat to some extent. Another role of zinc can be maintaining the structural position of the macromolecules inside the membrane and maintaining the integrity of the cell membranes, as well as the effective role in transfer systems.

Zinc sulfate reduces the impacts of boron abuse in soils with an excess of boron content.

Zinc transfer in the plant:

In plants, zinc is transferred from root to stem and leaf by xylems. Zinc transfer from older leaves to younger leaves also occurs during the growth of seeds.

Zinc in the soil:

The total content of zinc in the soil can range from 10 to 300 mg/kg.

The pH of the soil is very effective in solubility. As, the higher the soil alkalinity (calcareous), the more difficult the absorption of zinc for the plant. The presence of compounds such as hydroxide and carbonate ions causes the formation of zinc hydroxide and zinc carbonate, reducing the zinc solubility and absorption for the plant.

Moreover, high levels of phosphorus can cause zinc deficiency, since in addition to reducing solubility, it prevents root growth and the plant will not be able to access the zinc sources in the deeper areas of the soil.

Excessive amounts of copper ion reduces plant access to zinc as well, as absorption of both ions takes place with the same mechanism. Since the copper and zinc ion adsorption mechanisms are similar, excessive copper ion[2] level can be the cause of zinc deficiency in the plant.

Using zinc sulfate[3] in saline soils with high pH and calcareous soils can be very beneficial. Because zinc sulfate can reduce pH and thus control it, hence facilitating the absorption of nutrients for the plant.

Most of the zinc in the soil is inaccessible to the plant due to its specific position, and the use of the external source of zinc is of particular importance for soil fertility.

Zinc deficiency in agriculture:

It is very easy to identify zinc deficiency in the soil under cultivation. Usually, the examination and analysis of the soil under cultivation and the plant leaves yield acceptable results regarding zinc deficiency, and when the plant experiences zinc deficiency, several methods can be employed to improve it quickly and effectively.

Soil zinc deficiency, depending on the sensitivity of the plants, will have destructive effects in varying degrees. Plants such as rice, soybeans, corn, wheat, pea, and grapes are more sensitive to zinc deficiency, while some other products such as carrots, barley, and other forage crops[4] are more resistant to zinc deficiency.

The reasons for zinc deficiency are:

* Calcareous soils, high pH

* High concentrations of bicarbonate in irrigation water because of causes such as continuous droughts

* Uncontrolled and excessive use of phosphate fertilizers, which cause reduction in root growth and zinc solubility in the soil.

* Improper use of fertilizers containing zinc or zinc sulfate

Signs of zinc deficiency in different plants:

Burned spots in the veins, yellow color of relatively old leaves and even young leaves, small plant size, young leaves at the end of the branches that take the rosette[5] form, drying of some plant tissues, and delayed ripening of products and inappropriate growth are the symptoms of zinc deficiency.

Other symptoms of zinc deficiency include dwarfism and the small distance between nodes, yellowing of young leaves, deformation and twisting of the margins of leaves, and the drop of quality of the fruits.

It should be noted that zinc amount is inversely proportional to plant age. In other words, older plants have a lower amount of zinc and zinc deficiency symptoms are more severe in them.

Damage caused by zinc deficiency:

Drop of fruit of trees during their evolution is one of the most important damages due to zinc deficiency. In these conditions, sometimes up to 80% of the fruit of the trees will fall. In citrus, zinc deficiency emerges by thickening and whitening the skin. Naturally, such products will not be capable to be supplied to the market. For example, in the case of apple trees suffered from a zinc deficiency, the apple size is reduced to the size of a walnut.

Prevention and treatment:

Zinc deficiency is commonly observed in new gardens where their lands are virgin or leveled. Therefore, it is recommended that, prior to culture, the condition of zinc be examined in the soil of such areas and, in case of a deficiency, try to modify it based on scientific principles and using fully specialized methods and individuals.

Since zinc should be absorbed as a soluble form as a dual capacity Zn+2 cation, two compounds of Zinc Chelate or zinc sulfate are recommended to modify zinc deficiency.

Symptoms of zinc overdose:

In soils with low pH, zinc overdose may take place. The most important symptom of zinc overdose is the change in the color of the network of leaf veins[6] into dark green.

It is strongly recommended to use any kind of fertilizer based on the soil test result, and only after consultation with the experts.

The use of zinc sulfate fertilizer produced by Dezpart Gohar Kimia Sepehr Co. is recommended because:

  1. Because of its high solubility, it can be the best source of zinc in hydroponic culture.
  2. Farmers can use this fertilizer as solution spray in drip irrigation and sprinkler irrigation.
  3. Heavy elements that are harmful to human and plant health are removed in the process of production of this fertilizer.