Source. It is available as exchangeable cation in the soil. It is easily leached and thus become deficient in sandy soils during rainy season.

Regions. It is required in leaves. Magnesium is withdrawn from the ageing leaves and finally exported to the developing seeds.

Functions. Magnesium activates enzymes in phosphate metabolism. It acts as a constituent of chlorophyll.

It is responsible for maintaining ribosome structure. It is readily mobile and when its deficiency occurs, it is apparently transferred from older to younger tissues, where it can be neutralized in growth processes. Magnesium is essential for the synthesis of fats and metabolism of carbohydrates and phosphorus.

Deficiency symptoms

(i) Chlorosis,
(ii) Severely affected leaves wither and shed.
(iii) Leaves may develop necrotic spots.