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The Indian Council of Agricultural Research (ICAR) has recommended the use of ammonium sulphate for paddy cultivation as a low-cost fertilizer option to help farmers improve crop nutrition and maintain soil fertility. The recommendation comes amid growing concerns over India's heavy dependence on urea, fertilizer import disruptions from West Asia, and widespread sulphur deficiency in Indian agricultural soils.

What is Ammonium Sulphate?

Ammonium sulphate — chemical formula (NH?)?SO? — is an inorganic, water-soluble mineral fertilizer produced by reacting ammonia with sulphuric acid. It is also recovered as a valuable industrial byproduct from coke-oven gases in steel plants and from the manufacture of caprolactam (used in nylon production) and other metallurgical and chemical processes. This dual origin — direct synthesis and industrial recovery — makes it a resource-efficient fertilizer with significant circular economy value.

Its key nutritional composition: 21% Nitrogen (in the ammonium form) and 24% Sulphur (as active sulphate) — making it one of the richest dual-nutrient fertilizers available.

Why Ammonium Sulphate for Paddy?

Rice farmers frequently apply ammonium sulphate to flooded soils since nitrate-based fertilizers are a poor choice for waterlogged paddy fields due to denitrification losses — the microbial conversion of nitrates into nitrogen gas under anaerobic conditions. The ammonium form of nitrogen in ammonium sulphate is more stable in flooded, oxygen-deficient paddy soils, making it agronomically superior to urea in such conditions.

Additionally, paddy cultivation in India is heavily concentrated in alkaline and sulphur-deficient soils across states like Uttar Pradesh, Punjab, and Haryana. Ammonium sulphate addresses both challenges simultaneously — its acidifying effect lowers soil pH in alkaline soils while replenishing sulphur, which is increasingly becoming a deficient macronutrient in Indian farmlands due to the shift away from sulphur-containing fertilizers.

Sulphur plays a critical role in protein synthesis, chlorophyll formation, oil content in oilseeds, and quality parameters of cereals — making sulphur nutrition essential for both yield and produce quality.

The Urea Problem: Why a Shift is Needed

India's fertilizer economy is dangerously skewed toward urea, which accounts for the bulk of nitrogen fertilizer consumption. This creates multiple structural problems: fiscal pressure through enormous subsidies (urea is the most heavily subsidised fertilizer), soil nutrient imbalance (urea provides only nitrogen, exacerbating sulphur and other micronutrient deficiencies), and import vulnerability (India imports significant quantities of urea and its feedstocks).

Fertilizer imports from West Asian suppliers including Saudi Arabia, Qatar, UAE, Oman, and Israel are facing major shipping and logistics disruptions due to ongoing regional conflict in 2026 — making diversification of India's fertilizer basket both an agronomic and a strategic food security imperative.

Broader Applications of Ammonium Sulphate

Beyond agriculture, ammonium sulphate finds use across several industries: water treatment (as a coagulation aid), food processing (as a dough conditioner and food additive approved under FSSAI standards), pharmaceuticals (protein precipitation in biologics manufacturing), and textile processing (in dyeing and printing). Its multisectoral utility underscores its importance as an industrial chemical beyond the farm