DAP (diammonium phosphate)

Diammonium phosphate (DAP) is a nitrogen-phosphate compound fertiliser with the formula (NH₄)₂HPO₄, manufactured through the reaction of ammonia and phosphoric acid. Its standard grade 18-46-0 denotes 18 % ammoniacal nitrogen and 46 % P₂O₅. It ranks among the three main finished goods of the phosphate sector, alongside MAP and TSP, and also serves as an intermediate in the production of NPK fertilisers and bulk blends.^[1]

Manufacture

The industrial process hinges on the neutralisation of phosphoric acid with ammonia, either via a direct pipe reactor integrated into the granulation drum, or through conventional pre-neutralisation in tanks. The former route harnesses the heat of reaction to evaporate water from the acid, thereby lowering recycle ratios and energy consumption; the latter yields a wetter slurry, demanding greater recycle.^[2] Ammonia thus stands as the chief feedstock, together with phosphoric acid derived from the attack of phosphate rock.^[3]

In terms of global flows, India uses predominantly imported ammonia to manufacture DAP, much as the United States does for DAP and MAP. Morocco, holder of the world's largest phosphate reserves, likewise imports ammonia for this purpose.^[4]

Agronomic uses

DAP exhibits high solubility: roughly 90 % of total phosphorus is water-soluble, with the remainder citrate-soluble.^[5] This immediate availability makes it particularly suited as a starter fertiliser for short-cycle crops. The nitrogen fraction, wholly ammoniacal, calls for soil incorporation to curb losses through ammonia volatilisation. In certain countries, trials of fortification with micronutrients or sulphur are under way to tailor the product to deficient soils.^[5]

Market and trade

The DAP/MAP pair accounts for half of world phosphate consumption in fertiliser form, the balance split between NPK fertilisers, SSP, TSP and other products.^[6] In 2023, global DAP production stood at 35 million tonnes, of which 16 million were exported^[1].^[1] The phosphate sector displays higher concentration than the nitrogen industry, though falling short of the concentration level seen in potash. Among the dominant players worldwide are Guizhou Phosphate Chemical Group in China, Nutrien and Mosaic in North America, OCP based in Morocco, Ma'aden operating from Saudi Arabia, and PhosAgro headquartered in Russia.^[7]

DAP prices follow a cyclical pattern, correlated with phases of overcapacity and undercapacity in the industry.^[8] Following the 2022 peaks, phosphate fertilisers remained comparatively firmer than nitrogen and potash, which triggered an erosion of phosphorus's share in total fertiliser consumption^[6].^[9] World P₂O₅ consumption contained in fertilisers reached 47.8 million tonnes in 2025, with a projection to 51.5 million tonnes by 2029, Asia and South America forming the main growth drivers^[10].^[10]