Diammonium phosphate, often known as DAP, tells a story about agriculture, mining, and chemical industry growing together. The push for better crop yields led researchers in the early 20th century to look for ways to boost soil nutrition. The development of industrial-grade DAP rode in with the rise of large-scale fertilizer production around the 1960s, stacking up alongside urea and MAP as the chemical answer to the global food call. Ammonia synthesis powered by the Haber-Bosch process changed the game, letting companies produce ammonium compounds on a huge scale. Rock phosphate became the backbone for the phosphorus supply. Over time, tweaks in production methods made DAP more cost-effective, better for long-haul storage, and easier to handle in bulk—important in places with huge tracts of farmland far from city infrastructure.
Take a walk through an industrial storage yard, and you’ll find DAP as off-white, beige, or grayish granules collected in big silos and sacks. Manufacturers know DAP by many names—diammonium hydrogen phosphate, ammonium phosphate dibasic, or simply fertilizer-grade DAP. This stuff packs more punch than regular compost or animal manure. It delivers both nitrogen and phosphorus in forms plants can absorb. DAP is one of those simple, stable salts that fit into industrial processes just as easily as farm cycles, thanks to its moderate solubility and non-hygroscopic grain.
This salt sits on the periodic table’s crossroads between ammonium and phosphate. Chemically, the formula is (NH4)2HPO4, showing its twin ammonium ions linked with a hydrogen phosphate anion. DAP dissolves well in water, keeping its pH mildly alkaline, usually above pH 7—making it kinder to soil than acidic monoammonium phosphate. Standard DAP granules carry between 18% nitrogen and 46% phosphate by weight. It stays stable under dry storage, but high humidity can cause caking and clumping that frustrate operators during blending. Pure DAP melts about 155°C and breaks down fast under strong acids.
On shipping containers, industrial DAP arrives stamped with net weight, batch number, and production date. Technical specification sheets from most suppliers list typical minimums: 98% purity, heavy metals below 20ppm, and water-insoluble residues under 0.1%. Moisture targets hover under 2%, since damp granules stick together. Labels warn about storage—ventilated, dry spaces far from strong acids or alkalies. Some factories add anti-caking agents to keep the material free-flowing. Bulk buyers inspect for loss on ignition, sieve analysis, and solubility, since flowability can determine whether product makes it to the hopper or plugs it up.
Manufacturers mix phosphoric acid with ammonia under controlled temperatures. Liquid ammonia gas meets technical-grade phosphoric acid in scrubbing reactors, generating an exothermic reaction. Once neutralized close to the 1:2 ratio of acid to ammonia, a slurry forms, which gets granulated, dried, and cooled. Some facilities finish the product with a drying stage or rotary drum, and screen out oversized particles for recycling. The process values precise pressure and mixing speed. Out-of-spec. conditions lead to clumped material, ammonia loss, or unwanted byproducts.
DAP dissolves in water to yield ammonium and phosphate ions. In acidic soils, ammonium releases as ammonia gas, which may escape as odor or fertilize certain bacteria. In alkaline soil, phosphate risks binding to calcium and magnesium. Chemists tweak granule size or blend DAP with micronutrients—think zinc or magnesium—to tweak uptake in tricky soils. Some producers try anti-dusting coatings or combinations with sulfur to help both application and plant nutrition. DAP’s wide acceptance comes from its compatibility with other compounds—mix it in a tank with urea or potash, and it won’t react or clump easily.
Ask for DAP, and suppliers might mention di-ammonium hydrogen phosphate, or refer to it by old trade names. Globally, codes like “Fertilizer Grade 18-46-0” reflect nitrogen and phosphate percentages. Bulk bags might read “NPK fertilizer” with accompanying numbers showing its main nutrient strengths. Chemical suppliers list DAP under CAS number 7783-28-0. It pops up in older literature as ammonium hydrogen phosphate dibasic—a mouthful that says the same thing in longer form.
Plant workers handling DAP gear up with gloves, aprons, and dust masks as standard. Product safety sheets warn about mild irritation if the dust gets into eyes or airways, but acute toxicity runs low. Fire risk stays minimal so long as the product stays dry—once mixed with strong acid or alkali, fumes can irritate. Warehouses maintain air exchange and monitor for accidental gas release. Strict guidelines prevent DAP from mixing with strong oxidizers, acids, or chlorine compounds. The main operational snag usually involves product leakage or dust buildup on conveyors or bagging machines—safety training covers cleanup and first aid. Disposal runs without drama, as DAP degrades naturally in normal soil.
DAP powers a huge chunk of modern commercial farming. Corn, wheat, rice, and soy all get their boost from this compound, especially in starter fertilizers at planting. Horticulture taps into DAP for orchards and nurseries. Chemical industry plants use DAP to fire up flame retardants, buffer solutions, and as yeast food in bioreactors. Water treatment plants sometimes use DAP to remove heavy metals or balance phosphate levels. Firefighters sprinkle DAP-based powders as fire retardant on vegetation. A few niche uses show up in ceramics or metal finishing, thanks to the phosphate’s reactivity. Most DAP still fuels the root-to-leaf life cycle—the green that feeds people in every corner of the map.
R&D teams in fertilizer giants and university labs invest in better delivery systems and smarter nutrient use. Precision agriculture looks to sensors and GPS to tune DAP rates for soil zones, cutting waste and off-site runoff. Chemists study smart coatings to slow down DAP dissolution, hoping to match nutrient release with plant growth cycles. Microbial seed treatments get tested alongside DAP granules to help crops snag more phosphorus before it locks up. Some labs inspect heavy metal contamination in rock phosphate sources—cadmium, for one, draws sharp regulatory limits in the EU. The global push for sustainable farming brings DAP under fresh scrutiny for soil health, environmental run-off, and recycling of phosphorus from waste streams.
Toxicity studies track short- and long-term exposure to DAP for both people and the wider food chain. Acute risks to workers look low, barring chronic dust inhalation. Food safety regs check for indirect effects—excess DAP sometimes raises concern about nitrate runoff, which can mess with groundwater. Chronic soil use stores more nitrogen and phosphorus than crops take up, driving algae blooms in rivers and lakes. Researchers look at whether phosphorus from fertilizer can accumulate as insoluble forms or mobilize in unexpected ways, but most field data points to runoff as the major challenge. Crop scientists and toxicologists press for smarter application, edge-of-field barriers, and waterway buffer zones to keep nutrients close to the root zone.
Agriculture’s future feels tightly linked to phosphate chemistry, DAP included. The push for higher yields in the face of climate risk, resource scarcity, and urbanization keeps DAP relevant, but there’s strong pressure to squeeze more out of each granule. Circular economy projects eye phosphorus recovery from wastewater and animal manure to supplement DAP production. As the price of phosphate rock climbs and mines deplete, companies rethink supply chains and invest in recycling. Clean-label farming, organic inputs, and tight residue limits put pressure on DAP to play nice with other nutrient sources and pollute less. Technology, from drone soil testing to smart fertigation, shapes how and when DAP lands on the field. The chemistry may be old, but the conversation around DAP moves forward with every passing harvest, every regulatory change, and every fresh round of environmental data.
Diammonium phosphate, or DAP, usually brings up images of sprawling green fields and bags of fertilizer in a hardware store. Though agriculture grabs most of the spotlight, factories and processing plants across the world keep DAP close at hand for reasons beyond helping crops grow.
Many folks think of red trucks and brave firefighters, but chemical companies quietly play a big part in slowing flames. DAP steps up as a key ingredient in fire retardants used to drop on wildfires. It lands on dry grass and brush, cutting back the chance that a rolling fire will pick up speed. Planes release a reddish slurry, with DAP acting as the backbone, creating a barrier between flames and fresh fuel. California’s wildfires highlight just how important crews see DAP — they use thousands of tons every year.
DAP isn’t just a helper in the field; it finds a job in factories that craft goods like yeast and cheese. Food-grade DAP tweaks acidity and boosts fermentation, giving bakers more control and higher yields. Bread rises better, brewers get better foam, and cheesemakers coax out just the right texture. Food scientists treat it almost like a trusted kitchen hack.
I’ve seen large bakeries mix DAP into doughs, shaving off time and energy as the yeast bubbles up faster. Smaller craft brewers appreciate the way it keeps fermentation on track, as the ammonium ions feed hungry yeast cells.
Factories that plate or coat metals lean on DAP, too. In phosphate coating, it prepares steel for painting or powder coating, helping that protective layer stick. Without it, the world would see more rust, less durable tools, and more expensive repairs. I once worked in a plant spraying truck parts with coatings where nothing worked until we fixed the DAP dosage — then the paint clung, and the quality soared almost overnight.
Water treatment plants have plenty to manage: algae, minerals, and pollution. Some turn to DAP as a nutrient source in biological treatment processes. Adding phosphorus and nitrogen in the right mix feeds helpful microbes breaking down waste in industrial water streams. Without these nutrients, the tiny bacteria can stall, letting pollution slip through untreated.
Demand for DAP keeps going up, but each use comes with questions about runoff and chemical exposure. Plants rely on it, but too much can trigger algae blooms and mess with water ecosystems. Food and fire-fighting use spark concern, too; even the best solution brings trade-offs. Manufacturers and governments have started setting stricter guidelines and exploring recycling programs, hoping to shave off the waste and side effects.
Whether bread rises in a bakery, flames slow on a forest edge, or steel holds up against rust, DAP stays behind the scenes, doing the heavy lifting. More folks are pushing for safer use, tighter regulations, and better method sharing to keep its benefits in play without laying new problems at our door. DAP proves that even familiar chemicals have a life far beyond the farm, shaping the things we use every day.
Diammonium phosphate, known better as DAP, lines the shelves of warehouses and agricultural supply yards around the world. Every time I’ve come across a 50-kilo bag, I notice the big numbers stamped on the side: 18-46-0. This shows off its composition, with 18% nitrogen and 46% phosphate. DAP’s chemical formula, (NH4)2HPO4, holds up as a sturdy recipe — solid, granular crystals made in giant reactors where ammonia and phosphoric acid are combined on a commercial scale.
Industrial grade DAP usually skips the polish you see in “food grade” or “fertilizer premium” products. Its phosphorous, most important for root development and early growth, sits front and center. The nitrogen, released after water pops the compound apart, supports leafy, green growth — big, green plants mean good news in farming.
Factories churn out industrial DAP with purity ranging from 98% down to about 91%, depending on the source of the raw phosphoric acid and ammonia. With some batches, you get a slight dusting of impurities. There’s always a whisper of iron or aluminum oxides below 0.5%, a touch of heavy metals like cadmium and arsenic riding in at parts-per-million. My first bag felt gritty, not slick—the telltale sign of an industrial blend, not a white powder destined for pharmaceuticals.
Chloride and sulfate sometimes sneak in, lagging around 0.1-0.5%. Manufacturers keep those in check because crops are sensitive to excess chlorides, and high-sulfate DAP can upset soil pH. Moisture content hovers around 2%, enough to prevent caking, but not so much the granules turn to mush.
Color swings from light gray to darker tan. Clean white or very bright is rare—those batches usually cost more and serve niche purposes. Some visible dust or free ammonia odors don’t raise eyebrows for most farmers, but this would get denied in electronics or food processing.
Anyone spreading industrial DAP on a field or using it in a factory process knows purity isn’t just an academic detail. Impurities lower the actual amount of useful nutrients per ton, so you end up hauling more bags for less yield. Heavy metals in fertilizer can stack up in soil and raise red flags for food safety. I’ve heard growers argue over what’s an “acceptable” mix; those chasing high-purity materials typically believe in cleaner, more consistent results, but low-purity blends tempt buyers with better prices.
Big users, especially those in food or water treatment, set their own tight requirements. They send samples out for analysis, checking for contaminant spikes. Over the past decade, countries like China and India rolled out stronger standards for agriculture after realizing just how much heavy metal can threaten both export reputations and long-term soil health.
Clear labeling always helps, but I’ve seen sacks marked “industrial” with barely a hint about impurities. Farmers and buyers need better disclosure. Local governments and big cooperatives should invest in routine testing. Random spot checks hold suppliers accountable. On the industry side, factories applying cleaner process technologies bring down impurity levels from the start. Buyers, especially from smallholder backgrounds, gain from simple training on how purity changes crop results—and, later, farm profits.
DAP will keep anchoring big agriculture and industry. Chasing high purity pays off for both food security and environmental safety, especially as more corners of the world clamp down on what goes into their soil. Honest information and tighter controls let everyone use it with more confidence—and less guesswork.
Diammonium phosphate helps crops grow better and faster. Fields rely on it to feed wheat or rice, but away from farmlands, safety demands full attention. Anybody who’s unloaded bags of fertilizer knows careless storage can create bigger problems than a patchy lawn. I once saw a broken sack split near a barn in summer — soon, the place stank and insects swarmed. A small mistake with storage kicked off a week’s worth of hassle and cleanup.
Reacting to warmth and moisture, diammonium phosphate can clump or degrade, even create slippery surfaces that make walking risky. The dust, too, can irritate throats and eyes. In very rare cases, that dust can spark if it hits a direct flame, though it doesn’t easily catch fire by itself.
Humid barns or open sheds turn fertilizer into a sticky mess. Dry, covered sheds with a strong roof make things easier and keep water out. Enough space off the ground prevents bags from soaking up dampness. I always lean towards using wooden pallets or metal racks, stacked so air can flow between each layer.
Stacking bags in a pyramid or against a wall can tip if you’re not careful. Reach for a step stool or sturdy ladder if you need a sack from higher up—lifting too much or stretching to grab a bag can strain your back. Keep walkways clear in the storage shed. I learned this the hard way, tripping over a stray bag once and ended up with a badly scraped knee.
Dry sweepers or simple brooms do the job if a bag splits. Avoid using water since it makes the fertilizer clump worse and increases the mess. Wear gloves—long exposure to the dust can dry out skin and leave it itchy for hours. Once a spill is swept, take it outside or toss in the appropriate bin rather than dumping near a drain. Fertilizer in stormwater can rapidly create algae blooms in creeks, hurting fish and water quality.
Handling any fertilizer for hours without a mask or goggles isn’t worth the irritation. Even outside, breezes can blow powder back into your face. Basic featherweight dust masks and plastic safety glasses help a lot. At the end of the workday, wash hands before eating or drinking. I once forgot to do this after spreading fertilizer, and the taste while snacking on a sandwich wasn’t pleasant.
Every bag in the shed should have a readable label. Big, bold marker writing on stacked bags can save minutes and confusion later, especially if families or neighbors store grain and other farm chemicals nearby. Mix-ups can be costly or dangerous. Show anyone working with diammonium phosphate where safety gear is kept and walk through spill clean-up steps together. Misunderstandings often lead to accidents.
Good ventilation, locked doors, and sturdy shelving bring peace of mind. Simple checklists hanging by the shed door help anyone remember steps before opening or stacking new shipments. If possible, post emergency numbers and brief first aid info where everybody can see. Investing time in better systems pays off in fewer mistakes and lighter workdays.
Even in small amounts, thoughtful storage and clear routines keep neighborhoods and workers alike safe, letting fields thrive without sowing risk along with the seeds.
Digging into the world of fertilizers, Diammonium Phosphate (or DAP) stands out for its solid reputation in agriculture and industry. After several years working in chemical supply, I’ve unpacked more pallets of DAP than I’d care to count. Most folks don’t realize this product has a story before it hits a factory or a farm. The way it’s handled and packaged can tell you plenty about its future usefulness.
Walk through any fertilizer depot, and one thing becomes clear: DAP is heavy, dusty, and comes in plenty of forms. Most shipments arrive packed in large woven polypropylene bags lined with plastic, usually with a capacity anywhere from 25 kilograms up to the one-metric-ton “big bags.” I’ve often encountered the smaller bags at retail sites, but out at production plants or port storage, it’s those hefty one-ton bulk bags dominating the floor.
For operations with major volume, DAP sometimes just travels loose in railcars or truck beds. At that scale, there’s less fuss about pretty packaging—pressure sits squarely on efficiency. Still, this method demands covered storage at the destination, because, as I’ve seen, a little moisture goes a long way toward causing trouble.
Working with DAP isn’t tricky on most days, but getting careless about water almost always leads to headaches. It takes in moisture from the air, which sets up clumping, caking, and eventual breakdown of the granules. This isn’t just a question of tidiness. Lumpy fertilizer pours poorly, dissolves erratically, and can even impact the chemical processes in whatever industrial use it's headed for.
I’ve opened more than a few “resealed” bags from damp warehouses and watched otherwise clean DAP fall out in hard, useless lumps. Once moisture finds its way in, there is rarely an easy fix. Good suppliers keep this in mind with double-layered or laminated bags—not just for looks, but for defense against the elements.
When folks ask about shelf life, the answer lies less in chemistry and more in warehouse practice. Kept dry and cool, DAP can sit several years without major loss of quality. Most manufacturers will label shelf life at around two years, but this isn’t set in stone—proper storage can stretch that further. If humidity sneaks in, deterioration follows quickly. Sometimes, DAP stored improperly needs tossing after just a season.
Solving these packaging and storage issues isn’t rocket science, just common sense and decent investment. Spending a bit more on waterproof liners or using heat-sealed plastic inner layers pays off every time. At the warehouse level, using pallets to keep bags off the ground, along with keeping storage covered and ventilated, prevents most moisture mishaps.
Bulk handlers have to get creative, especially in wet climates, putting up simple covered bins or tarps to fend off dew and rain. Even in hot, dusty places, it’s surprising how morning condensation spells disaster if ignored. As an industry, pushing for better handling up and down the chain not only saves product but keeps costs down by reducing waste. And that’s a win for every part of the supply chain, from shipper to final user.
DAP, or diammonium phosphate, shows up on farm supply shelves and in industrial catalogs all over the world. As farmers, gardeners, or folks running large-scale operations, we often assume that if something looks official and carries the right technical name, it must follow the rules. Still, not every bag stamped “DAP” means the same thing or meets expectations you actually rely on.
Most industries count on some form of outside verification. In fertilizers, ISO (International Organization for Standardization) or country-specific standards like BIS in India guide raw material purity, nutrient content, trace elements, moisture, and heavy metals. Companies sometimes chase international certifications for export—think ISO 9001 for quality management or certain European “EC Fertilizer” standards. Yet, in my own experience watching farms order shipments from different suppliers, labels don’t always match reality.
Common sense says you need that DAP bag to hit advertised nutrient percentages—mainly at least 18% nitrogen and 46% phosphate. If the content falls short, crops underperform, and that investment washes away. Extra fillers aren’t just a ripoff; unexpected chemicals inside, brought in as cheap fillers, can actually harm the land and water around it.
In one season, a local farmer down the road bought what he thought was properly certified DAP, but a government lab check found unacceptable cadmium levels, which can transfer to food and pose health risks. That scare showed us that industry standards only help if they’re backed by regular, independent testing—not just paperwork or websites.
Many buyers lean too much on brand names or distributor promises. But industry bodies like the Fertilizer Association of India and their international peers publish lists of certified manufacturers, complete with product codes and batch details. Good suppliers push to prove their products with accessible lab reports, QR codes, or online databases. Over the years, talking to suppliers willing to open up their records, or even inviting buyers to see their processes, built a different kind of confidence than any print label.
The truth is, enforcement sometimes falls behind the standards on paper. Counterfeit bags can slip into the supply chain, particularly in peak season when demand surges. During one planting season, rushed shipments meant some traders cut corners. Smarter buyers in our area shared batch numbers and flagged suspicious quality, which eventually led authorities to act. This kind of community sharing tends to catch what regulators alone might miss.
Pushing for digital traceability helps. Systems letting customers scan and verify product details against a central registry—or even share quality reports—crack down on fakes. Support for local labs is key; without frequent, random checks, cheats slip through. Government and large cooperatives can nudge forward change by rewarding transparent suppliers with long-term contracts, not just one-off orders at the lowest price.
Ultimately, as a buyer, don’t just take the sticker at face value. Reach out for technical sheets, ask for lab results, talk to neighbors about bad batches, and keep an eye on policy news around fertilizer safety. Better habits from the ground up make a bigger difference than even the fanciest logo.
| Names | |
| Preferred IUPAC name | diammonium hydrogen phosphate |
| Other names |
Ammonium hydrogen phosphate DAP Diammophos Diammone Phosphoric acid diammonium salt |
| Pronunciation | /daɪˌæmˈoʊniəm ˈfəʊs.feɪt/ |
| Identifiers | |
| CAS Number | 7783-28-0 |
| Beilstein Reference | 358928 |
| ChEBI | CHEBI:63042 |
| ChEMBL | CHEMBL1201733 |
| ChemSpider | 72812 |
| DrugBank | DB11242 |
| ECHA InfoCard | 06b4d0fd-5e37-4d1d-8e9b-9e6f3a6e9de8 |
| EC Number | 231-987-8 |
| Gmelin Reference | 70692 |
| KEGG | C00208 |
| MeSH | Ammonium Phosphates |
| PubChem CID | 1032 |
| RTECS number | BQ9625000 |
| UNII | FI9X3475U2 |
| UN number | UN2061 |
| CompTox Dashboard (EPA) | DTXSID6021323 |
| Properties | |
| Chemical formula | (NH4)2HPO4 |
| Molar mass | 132.06 g/mol |
| Appearance | White granular or powder |
| Odor | Odorless |
| Density | 1.62 g/cm³ |
| Solubility in water | Soluble in water |
| log P | “-1.8” |
| Acidity (pKa) | 7.2 |
| Basicity (pKb) | 11.7 |
| Magnetic susceptibility (χ) | '-58.0·10⁻⁶ cgs' |
| Dipole moment | 2.99 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 132 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -242.0 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -2385 kJ/mol |
| Pharmacology | |
| ATC code | V06DF |
| Hazards | |
| Main hazards | May cause irritation to eyes, skin, and respiratory tract. |
| GHS labelling | GHS07, GHS09 |
| Pictograms | GHS07 |
| Signal word | Warning |
| Hazard statements | H319: Causes serious eye irritation. |
| Precautionary statements | Keep container tightly closed. Store in a dry, well-ventilated place. Wear protective gloves and eye protection. Avoid breathing dust. Wash hands thoroughly after handling. Dispose of contents/container in accordance with local regulations. |
| NFPA 704 (fire diamond) | 2-0-0 |
| Autoignition temperature | > 400°C |
| Lethal dose or concentration | LD50 (oral, rat): > 5,000 mg/kg |
| LD50 (median dose) | > 6,140 mg/kg (rat, oral) |
| PEL (Permissible) | Not established |
| REL (Recommended) | 0.5 mg/m³ |
| IDLH (Immediate danger) | Not established |
| Related compounds | |
| Related compounds |
Ammonium phosphate Monoammonium phosphate Monopotassium phosphate Diammonium hydrogen phosphate Nitrogen fertilizers Urea |
