Phosphorus management in agriculture: a review

Phosphorus is a major limiting nutrient for crop growth. Phosphorus chemistry in soil is complex with its unique property to become less available to crops with slow diffusion and high fixation. It is very well known fact that fate of P depends upon soil type, soil properties, rate of application and other factors. Although from past few decades there is a continuous application of phosphatic fertilizers in order to sustain high productivity alongwith other fertilizers which often exceeds crop uptake results in its accumulation in the soil. The accumulated phosphorus thus present in soil is lost if inorganic fertilizers are coupled with huge inputs of organics or animal manure. In many countries phosphorus is considered as non point source of water pollution and agriculture is the major contributor for this source. The phosphorus content causing eutrophication may be alarming from environmental point of view but may be very less from farmer point of view, but continuous loss of P from soil can be critical. Experiments carried out in long term fertilizer experiment in Punjab has already revealed the movement of P through soil profile, which indirectly hints high P build up in Indian soils. The approach using both quantity and intensity parameter like DPS can definitely play an important role in estimating the potential capacity of Indian soils over periodical basis. Soil testing alone cannot give the answers related to the issues of P under sub surface pathways and its accountability of loss. The areas with high soil P status should be identified and appropriate management strategies to be adopted to prevent P loss from soil.