Availability indices of calcium and magnesium in soils of Kerala

Bhindhu P.S., Sureshkumar P.


Calcium and magnesium are indispensible as secondary nutrients for plant growth. Availability of these nutrients to plants depends on the form and quantity present in soil. Soils of Kerala pose the problem of acidity due to high rainfall and leaching of bases causing widespread deficiency of these nutrients. A study was conducted to characterize the soils of the state with respect to availability indices and major fractions of calcium and magnesium contributing to plant available pool. The availability of calcium and magnesium increased with pH, cation exchange capacity and decreased with increase in exchangeable aluminium. The mean per cent contribution of different fractions to total calcium was in the order exchangeable > mineral > acid soluble > water soluble > organic complexed, whereas in the case of magnesium, it was mineral > acid soluble > exchangeable > water soluble > organic-complexed fractions. Exchangeable calcium and water soluble magnesium were the sole forms contributing directly to the available pool.


Calcium, magnesium, fractions, available pool

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