The worsening nutrient imbalance from over-application of urea and DAP

The easing of global prices has boosted fertiliser availability and cut the subsidy bill. However, asymmetry in the pricing structure has led to a worsening nutrient imbalance due to the over-application of urea and DAP.

Background:

• The year 2022 saw global prices of fertilisers go high due to the post-Russia invasion of Ukraine in February.
• Landed prices of urea imported into India (cost plus freight) are ruling at around $550 per tonne, as against $900-1,000 average in November-January 2021-22, when global demand for food and plant nutrients surged with the lifting of Covid lockdowns by most countries.
• The United Nations Food and Agriculture Organisation’s Food Price Index hit 159.7 points in March 2022.
  • From that all-time high, the index — which is a weighted average of global prices of a representative basket of food commodities over a base period value, taken at 100 for 2014-2016 — has fallen for nine consecutive months.
• However, till December 2022 a number of 132.4 points was below even the year-ago value of 133.7 points and the lowest since the 129.2 points of September 2021.

India’s Fertiliser consumption:

About Di-ammonium Phosphate (DAP):

• It is a very popular fertilizer because of its excellent physical properties and nutrient content.
• It is free-flowing, dust-free and does not normally give any storage problems.
• DAP is almost water-soluble and ultimately leaves an acid effect on soils because of the ammonia (NH4) it contains.
• DAP on incorporation into soil reacts with water and gets converted into HPO4 and NH4.
  • Ammonium (NH4) follows the same routes as in the case of urea.
  • Phosphorus in DAP is present in the best available form (HPO4).
• Depending upon the soil reaction (pH), phosphorus exists in 3 forms which can be absorbed by plant roots.
• These are HPO4, H2PO4 and PO4. Phosphorus, which is immobile in the soil, is not subjected to leaching losses.

Reasons behind increased consumption of urea and DAP:

• High subsidy on urea: The government has fixed the maximum retail price (MRP) of urea at Rs.5,628 per tonne, while the MRPs of other fertilisers are technically decontrolled.
• DAP – a cheaper substitute: Companies have been told not to charge more than Rs.27,000/tonne for DAP (Rs.29,000-31,000/ tonne for NPKS complexes), which has 46% P and 18% N.
  • Thus, the choice of fertilisers is primarily a function of prices and not of NPKS complexes or other macro and micronutrients in the fertilisers.

What are the impacts of global ease on the prices of fertilisers?

• It significantly improves overall availability. No major shortage of any fertiliser, except MOP, has been reported during the ongoing Rabi cropping season.
• Reduction in fertiliser subsidy of the government.

Challenges emerged:

• Over-use of fertilisers: India’s fertiliser sector has been riddled with distortions from excessive use of urea. The diammonium phosphate or DAP is seeing a similar phenomenon of over-application due to underpricing. The effects of overconsumption of urea and DAP:
  • The current NPK ratio of 13:5:1, as against the ideal 4:2:1, would adversely affect crop yields
  • It will adversely affect the health of plants and humans, due to the unavailability of a balanced nutrient mix.
• Increase in Urea consumption: Urea has 46% nitrogen (N), while DAP contains 46% phosphorus (P) plus 18% N and MOP has 60% potassium (K).
• Neem oil supposedly also acted as a mild nitrification inhibitor, allowing a more gradual release of nitrogen. Increased nitrogen use efficiency would, in turn, bring down the number of urea bags required per acre.
• Worsening of nutrition imbalances: The consumption of both urea and DAP has shot up, with their sales for the year ending March 2023 likely to top 350 lt and 120 lt respectively.

Suggestive measures:

• To restrict DAP used to rice and wheat.
  • The danger is of even this well-accepted fertiliser loses out to DAP because of flawed pricing.
• To raise SSP’s acceptance by permitting sale only in granular, not powdered, form.
  • SSP powder is prone to adulteration with gypsum or clay.
  • Farmers can be assured of quality through granules, which will also promote a slower release of P without drift during application.