Di-ammonium Phosphate (DAP) is a high-concentration, water-soluble chemical compound primarily used as a fertilizer, making it a crucial concept in Indian agriculture and economy, not a legal or political one. Its chemical formula is (NH₄)₂HPO₄, and the standard fertilizer grade contains 18% Nitrogen (N) and 46% Phosphorus (P₂O₅), often expressed as 18-46-0.
DAP is produced by reacting ammonia (NH₃) with phosphoric acid (H₃PO₄), a process that became commercially popular globally in the 1960s. It solves the problem of nutrient deficiency in soil by providing two essential macronutrients: Nitrogen, which promotes green leafy growth and photosynthesis, and Phosphorus, which is vital for root development, flowering, and energy transfer in plants.
The mechanism of DAP involves its high solubility, allowing it to dissolve quickly in the soil to release plant-available ammonium and phosphate ions. Farmers in India commonly apply it as a basal dose just before or at the beginning of sowing, as the high phosphorus content stimulates early root establishment. DAP is the second most commonly used fertilizer in India after Urea.
DAP is intrinsically connected to the Indian government's Nutrient Based Subsidy (NBS) Scheme, which was implemented in 2010 by the Department of Fertilizers, Ministry of Chemicals & Fertilizers. Under the NBS regime, a fixed amount of subsidy is provided on Phosphatic and Potassic (P&K) fertilizers, including DAP, based on their nutrient content, to ensure affordability for farmers.
The policy surrounding DAP has seen recent changes due to global price volatility of its raw materials like phosphoric acid and ammonia. The government has repeatedly extended a One-time Special Package on DAP beyond the regular NBS subsidy to keep the retail price unchanged for farmers. For instance, the Union Cabinet approved the extension of this special package at ₹3,500 per Metric Tonne beyond the NBS subsidy from January 1, 2025, until further orders, ensuring the retail price remains fixed at ₹1,350 per 50-kg bag. This special package supplements the existing NBS scheme, which continues to govern the subsidy on 28 grades of P&K fertilizers.