Over-application of Urea and DAP

Why in news?

India’s fertiliser sector which has been riddled with distortions from excessive use of urea is seeing a similar phenomenon of over-application of Di-ammonium phosphate (DAP) due to underpricing.

What are the major reasons behind over usage?

The ideal Nitrogen, Phosphorus, Potassium (NPK) use ratio is 4:2:1.

High fertilizer subsidy - High government subsidies are behind the low pricing, and high sales, of these two fertilisers.
Under the Nutrient based subsidy scheme, a fixed amount of subsidy, decided on an annual basis, is provided on each grade of subsidised phosphatic and potassic (P&K) fertilisers, except for urea, based on the nutrient content present in them.
Cooling of global fertilizer prices - The easing of global fertilizer prices significantly improved overall availability of the fertilizers, except Muriate of Potash (MOP), during the ongoing rabi cropping season.
India is the top country by diammonium phosphate import in the world.

What efforts were taken to optimize the fertilizer usage in India?

Urea has 46% nitrogen (N), while DAP contains 46% phosphorus (P) plus 18% N and MOP has 60% potassium (K).

NBS scheme - The nutrient-based subsidy (NBS) scheme was launched in 2010 to discourage farmers from applying too much urea, DAP and MOP.
By moving away from product-specific subsidy, to one where the government fixed a per-kg NBS rate for each nutrient (N, P, K and sulphur or S), it was expected to promote balanced fertilisation.
It also meant more use of complex fertilisers and single super phosphate (SSP, which contains 16% P and 11% S).
Neem coating of urea - The government made coating of urea with neem oil compulsory from 2015-16, to check illegal diversion of the heavily-subsidised fertiliser for non-agricultural uses.
Neem oil acted as a mild nitrification inhibitor, allowing a gradual release of nitrogen thus promoting nitrogen use efficiency.

What is the concern now?

The current fiscal has witnessed a worsening of nutrition imbalances.
Consumption of both urea and DAP has shot up while the sales of complexes (SSP and MOP) have reduced.
The problem is attributed the imbalances to “disturbances in the price hierarchy”.
Among the non-urea fertilisers, the maximum retail price (MRP) was normally the highest for DAP and lowest for MOP.
But it’s the other way round now, prompting the farmers to use more DAP.

What is the road ahead?

Restriction of DAP - The DAP use must be restricted to rice and wheat.
All other crops can meet their Phosphorus requirement through SSP and complexes.
Promotion of SSP - The SSP’s acceptance can be raised by permitting sale only in granular and not in powdered form as SSP powder is prone to adulteration with gypsum or clay.
Farmers can be assured of quality through granules, which will also promote slower release of P without drift during application.

Quick Facts

Urea

Urea is a source of nitrogen, an essential nutrient crucial for crop growth and development.
Urea is the most important nitrogenous fertilizer in the country because of its high N content (46%N).
It is a white crystalline organic chemical compound with neutral pH.
Urea is widely used in the agricultural sector both as a fertilizer and animal feed additive.

Di-ammonium phosphate (DAP)

DAP is a water-soluble ammonium phosphate salt which is produced by the reaction of ammonia with phosphoric acid under controlled conditions.
DAP is the 2^ndmost commonly used fertiliser in India after urea and farmers normally apply this fertiliser just before or at the beginning of sowing.
It is a basic nutrient for Rabi crops like mustard and wheat.
Fertilizer grade DAP contains 18% Nitrogen and 46% Phosphorus (P2O5).
Though there are other phosphatic fertiliser such as Single Super Phosphate (SSP), DAP is the preferred source since it contains nitrogen as well.

References

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