Soil Nutrient management
Micronutrients
Zinc
Zinc ions (Zn2⁺) are held on the surface of clay and organic matter particles. Soil organic matter holds zinc in a chelated form. Chelation is a process by which certain metals are held within the structure of large organic molecules.
Zinc, like most micronutrients, is mostly immobile in the plant, and deficiency symptoms appear first in the newly emerging leaves. Frequent symptoms associated with zinc deficiency include, stunted plants, light green areas between the veins of new leaves, smaller leaves (little leaf), and shortened internodes (rosetting).
Zinc toxicity depends on pH, which controls the concentration of zinc in solution. High concentrations of zinc can cause toxicity in plants. The general symptoms are stunting of shoots, curling and rolling of young leaves, death of leaf tips, and chlorosis.
Zinc availability decreases markedly as the soil pH increases; therefore, zinc deficiency usually is limited to soils with a pH above 6.5. Clay fraction of the soil exerts a strong attractive force for zinc ions as well as aluminum and iron oxides, and calcium carbonates.
Click on the following topics for more information on soil nutrient management.
