Magnesium- is a constituent of chlorophyll. It is required in fat synthesis and nucleic acid synthesis. It activates enzyme in phosphate metabolism.
(1) By adding farm yard manure or animal excreta to the soil.
(2) By adding fertilizers, manure.
(3) By green manuring.
(4) By crop rotation.
(5) By controlling over-grazing.
1. The essential elements should be necessary for growth and reproduction of the plant. It should be indispensable. The plant should not be able to complete its lifecycle in the deficiency of the element.
2. The element should not be replaceable and its requirement should be specific. The deficiency of the element should not be met by supplying some other element.
3. There should be direct involvement of the element in the metabolism of the plant.
(1) iron (2) zinc and calcium.
(2) Zinc : Due to the deficiency of zinc, young leaves and internodes become extermely small, resulting in little leaf rosette and mottled leaf condition .
Calcium : It's deficiency produces necrosis in the leaf and stem. Plants have a stunted growth with suppressed flowering. Flowers fall immaturely and this process is called premature fall of flower.