Phosphorus Fractions in Soils of India: A Review

The different nutrient element are exist in different fractions in the soil. The available form of nutrients is responsible for the change in yield of crop significantly. The availability of different pools involves not only their physico-chemical nature but also the ability of the plant to forage them with plant root system. In Indian soil total phosphorus ranges from 100 to 2000 ppm but the available phosphorus ranges from 2 to 20 ppm. The forms of phosphorus present in soil viz. organic and inorganic. The inorganic form of phosphorus constitute about 30-35 per cent of total phosphorus. The inorganic P consist of different pool such as aluminum, iron and calcium bound phosphorus constitutes active form of inorganic P. The reductant-soluble and occluded forms of phosphorus are relatively less active. Different types of phosphorus are interrelated and add to the pool of plant-accessible P as per their physical and chemical properties such as surface area, composition and solubility.