Why neem-coated urea is safer

Out of the total 17 nutrients required for healthy growth of a crop, nitrogen, phosphorous pentoxide, and potash are three major plant nutrients and adequate supply of all three is essential for healthy growing plants.

The ideal ratio of these nutrients is in the ratio of 4:2:1, but various factors have led to skewed use in India. According to Economic Survey of India (2013-14), the ratio deteriorated to 8:2.7:1 and in states such as Punjab and Haryana, it was as bad as 38:6:1 and 53:11:1 respectively. One of the reasons for this distorted use of fertilisers is subsidy given for urea. Introduction of High Yielding Varieties during Green Revolution in the 1960s and 1970s has necessitated the use of fertilisers and to ensure the same, the government has introduced subsidy to encourage fertiliser use. Over the years, this has led to distorted use.

Nitrogen plays a vital role in plant growth as it is the central component of chlorophyll, the compound essential for photosynthesis. Nitrogen is also a major component of amino acids, the building blocks of proteins, without which plants would wither and die.

Inadequate Nitrogen causes poor plant growth and inhibits leaves to make sufficient chlorophyll and consequently resulting in significant reduction in yield levels. Therefore, it is essential to maintain adequate levels of all three major nutrients on the soil. But, Indian soils are notorious for their low organic carbon. This deficiency is often overcome with the application of farmyard manure till a couple of decades back and now, with the application of synthetic fertilizers such as urea.

However, it is not that all the urea that has been applied to farm is utilised by plants. According to United Nations Framework Convention on Climate Convention (UNFCCC), due to its ready solubility, urea leaches out or even it volatilize into the atmosphere with a result of higher input costs and wastage of precious resources of farmers as well.

For the government, it is a waste of subsidy on urea. Currently, subsidy on urea is about Rs 16,000 per ton. This loss of urea has another dimension to it, the formation of nitrous oxide - an important Green House gas (GHG). The global warming potential of nitrous oxide is estimated to be 100 times more than that of carbon dioxide. As per Indian communication to the UNFCCC, current nitrous oxide emissions from farm application of urea is about 268.70 gigagrams and any increase in urea use would increase emissions of this GHG as well and escalate global warming phenomenon.

India, by 2030, will become the most populated country and to feed its growing population, India needs to produce an additional 100 million tonnes of food grains. As the option of increasing area under cultivation is limited, intensive agriculture with high yielding varieties and increased dose of fertilisers appear to be viable under the current state of technological development.

Such a shift would increase nitrous oxide emissions from the use urea. According to fertiliser industry projections, urea consumption would touch 41.6 million tonnes by 2020-21 and nitrous oxide emissions would raise several folds. Such increase in GHG emission could affect India's commitment to reduce GHG emission under the Intended Nationally Determined Contributions to control global warming. Such adverse impacts could have been resolved if the solubility of urea is reduced or brought down to match the speed of urea uptake by plant roots from the soil. Agricultural scientists registered a major success in achieving that by fortification of urea with oil extracted from the seeds of Neem (Azadirachta indica).

Scientists have found that neem seed oil effectively reduces the solubility of urea and ensures that it is not wasted through leaching and consequent contamination of groundwater neither volatilises into the atmosphere. In other words, coating urea with neem seed oil ensures that all the urea applied is utilised by the plants. It would bring down the quantity of urea per acre and consequent reduction in input cost to farmers.The emission of nitrous oxide is also brought down significantly. In view of these positive impacts, the Government of India, in a proactive move, has made it mandatory to use neem coated urea. Research studies have indicated that this measure will result in 10% decrease in the use of urea. About three million tonnes of urea worth Rs 450 million can be saved for the government from fertilizer subsidy, and make the agriculture sector climate friendly.