The nutrient of iron is needed for the production of chlorophyll or the green leaf of plants and the activation of several enzymes that are effective in photosynthesis and respiration of plants. Iron deficiency is often found in calcareous and alkaline soils. Plant-absorbable iron decreases in acidity above 7 (alkaline soils). The toxicity of manganese also increases iron deficiency and causes the leaves to develop uniformly and the leaves turn yellowish green in the youngest leaves. Other leaves of the plant remain dark green. At the beginning of iron deficiency in plants, the leaves are light and the veins remain green. If this micronutrient deficiency persists, the leaves will fade and if the leaves are exposed to sunlight, they will dry out and die.
Therefore, according to the above, the presence of iron in plants is necessary in the creation and maintenance of green seeds and also the production of carbohydrates, and iron deficiency and deficiency, causes the loss of chlorophyll and thus yellowing of leaves and reduced photosynthesis.
Iron deficiency in the plant:
In most parts of Iran, the most important reason for iron deficiency is the high amount of bicarbonate in the soil solution. The effects of iron deficiency can be seen in most products in different parts of Iran. Consumption of ferrous sulfate improves the nutritional conditions of plants and can eliminate iron deficiency. However, before using iron sulfate, soil pH should be corrected and alkaline and calcareous soils should be modified by adding substances such as ammonium sulfate to provide conditions for plants to absorb iron. The use of ammonium sulfate, in addition to reducing the acidity of agricultural soils, also provides plants with the need for nitrogen and sulfur.
Heavy irrigation of agricultural lands and orchards, compaction or any other factor that reduces soil aeration and drainage, increases the concentration of carbon dioxide in the soil and reacts in the presence of lime, during which bicarbonate is produced.
Irrigation water for agricultural lands sometimes contains bicarbonate, especially when it is supplied from deep wells. Aeration of these waters reduces the amount of bicarbonate by dropping from a height or consuming some sulfuric acid to lower the pH of the water.
To eliminate iron deficiency, the soil should be well drained and well ventilated. Reducing and modifying the pH of alkaline and calcareous soils also contributes to the process of iron supply in agricultural lands. Finally, by using iron fertilizers such as iron sulfate or iron chelate, soil iron and plants’ need for this nutrient can be provided.
