0-46-0 Fertilizer (TSP): Analysis, Rates and Price

0-46-0 fertilizer is triple superphosphate (TSP): it carries 0% nitrogen, 46% phosphate (P2O5) and 0% potash by weight, which works out to about 20% elemental phosphorus. A 100 lb bag supplies 46 lb of P2O5 and about 13 lb of calcium, according to University of Kentucky soil specialist John Grove (2024). This guide explains what the numbers on the bag mean, how much to spread for a given crop, how its price compares with DAP and MAP, and where the phosphate rock behind it is mined.

Below you will find a nutrient comparison chart, World Bank price data to September 2026, a rate-and-cost calculator, and a step-by-step method for turning a soil test into pounds of product per acre.

What 0-46-0 means on a fertilizer bag

Every fertilizer bag in North America carries a three-number grade, also called the analysis. The numbers are always in the same order: total nitrogen (N), available phosphate (written as P2O5, phosphorus pentoxide) and soluble potash (K2O). So 0-46-0 means no nitrogen, 46% P2O5 and no potash. The remaining 54% of the weight is mostly calcium, the hydrogen and oxygen bound to the phosphate, and small amounts of impurities carried over from the rock.

The P2O5 figure is a reporting convention, not the chemical form in the bag. To convert P2O5 to elemental phosphorus (P), multiply by 0.436 (the weight share of phosphorus in the P2O5 molecule). That gives 46 x 0.436 = about 20% P. To go the other way, multiply P by 2.29. Soil-test reports in the US Midwest usually give recommendations as lb P2O5 per acre, so most growers never need the conversion, but it matters when you compare TSP with products sold on a P basis or read a European label.

The grade is not fixed at 46. The USDA technical review of triple superphosphate lists the trade names 0-45-0, 0-46-0 and 0-50-0, and notes that the material generally contains 43-50% P2O5. Kentucky Extension gives a range of 44 to 52%, with 46% as the typical value. Always read the guaranteed analysis on the tag; a 0-44-0 product needs about 5% more product weight to deliver the same phosphate.

TSP percentages at a glance

What is triple superphosphate and how is it made?

Triple superphosphate is mainly monocalcium phosphate, Ca(H2PO4)2, usually with one molecule of water attached. It is made by reacting finely ground phosphate rock with phosphoric acid rather than with sulfuric acid. That one change is why TSP has roughly two and a half times the phosphate of single superphosphate (SSP, 0-20-0, which also contains sulfur), and why it carries very little sulfur.

The Purdue and Wisconsin extension guide NCH-13 describes the route in two stages. First, phosphate rock is treated with sulfuric acid to make phosphoric acid (the “wet process”). Second, that acid is mixed with more ground rock, and the slurry reacts, cures and is granulated. Because phosphoric acid brings its own phosphate into the product instead of diluting it with gypsum, TSP is the highest-analysis straight phosphate fertilizer on the market.

The Mosaic Company describes the same chemistry at its Brazilian plants in its 2024 annual report (Form 10-K): the rock and phosphoric acid react in a Kuhlmann-type reactor, the product cures on a pile for about seven days and is then granulated. The same filing states that one tonne of TSP needs about 1.4 tonnes of phosphate rock, against 1.6 to 1.7 tonnes for MAP and 0.6 to 0.7 tonnes for SSP.

Why it is called “triple”

The name dates from when ordinary superphosphate (about 18-20% P2O5, per the USDA review) was the standard product. Concentrated superphosphate held roughly three times as much phosphate, so the trade called it triple or treble superphosphate. The USDA review notes that “concentrated superphosphate” is the formal chemical name for the same material.

0-46-0 compared with DAP, MAP and SSP

TSP competes mainly with the two ammonium phosphates. Diammonium phosphate (DAP, 18-46-0) has the same phosphate content as TSP but adds 18% nitrogen. Monoammonium phosphate (MAP, 11-52-0) adds 11% nitrogen and has slightly more phosphate. Single superphosphate (0-20-0) has much less phosphate but supplies sulfur. Rock phosphate itself holds 25-35% P2O5, but only 0-10% of it is water-soluble, so it is a slow source used mostly in organic systems.

Chart

Phosphate content by fertilizer

Per cent P2O5 by weight, typical grade

Do these sources perform differently in the field? Mostly not. University of Minnesota nutrient management specialist Dan Kaiser writes that he would expect similar yield results whether MAP, DAP or TSP is used (updated October 2025). Kentucky Extension adds that differences between phosphate sources are small compared with the effect of placement. The choice is therefore mostly about price per pound of P2O5, whether you need the nitrogen, timing and what your dealer stocks.

If your soil test also shows low nitrogen and potash, a balanced grade may be simpler than three straight products; our guide to when 13-13-13 is used explains that trade-off. For DAP rates and costs in detail, see our DAP cost and application guide.

When to choose TSP over MAP or DAP

Because TSP has no nitrogen, it fits jobs where nitrogen would be wasted or harmful. Extension specialists point to four common cases.

• Fall phosphate for spring corn or soybean. Nitrogen applied in autumn with MAP or DAP is more likely to be lost before the crop can use it. Kentucky Extension favours TSP for fall applications ahead of next spring’s corn and soybean, and Minnesota notes TSP is offered for fall use where fall nitrogen should not be applied.
• Soybean, alfalfa and other legumes. These crops fix their own nitrogen. Grove favours TSP over MAP or DAP for direct spring application before full-season soybean.
• Calcareous or high-pH soils with seed-placed fertilizer. In-furrow DAP above about 15-20 lb N per acre can cause ammonia injury to seedlings on high-pH soils (University of Kentucky, 2024). TSP carries no ammonium, so there is no ammonia release.
• Custom blends. TSP lets a blender raise phosphate without changing the nitrogen line. Kaiser reports no compatibility problems blending TSP with nitrogen, potash or sulfur sources.

MAP or DAP is usually the better pick for fall-seeded small grains, canola and cool-season grasses, which can use autumn nitrogen, and for spring corn, where ammoniacal nitrogen and phosphate placed together can work well.

Does the calcium in TSP matter?

Rarely. At 100 lb TSP per acre you add about 13 lb of calcium, while most mineral soils already hold 2,000 to 6,000 lb of extractable calcium per acre (University of Kentucky, 2024). The addition does not interfere with potassium or magnesium uptake, and TSP is not a liming material.

How much 0-46-0 fertilizer per acre

The rate comes from a simple division: pounds of P2O5 you need, divided by the phosphate fraction of the product. For a 46% product the formula is lb TSP per acre = lb P2O5 needed / 0.46. In practice that means about 2.2 lb of TSP for every pound of P2O5.

1. Test the soil. Take a representative sample and ask the lab for Bray-1, Mehlich-3 or Olsen phosphorus, depending on soil pH and your state’s method.
2. Read the recommendation. Your state guide converts the test into lb P2O5 per acre, higher for “very low” and “low” categories, maintenance only for “optimum”, and zero above that.
3. Estimate crop removal. For maintenance, multiply expected yield by removal per unit. Iowa State’s PM 1688 (2013 revision) uses 0.32 lb P2O5 per bushel of corn grain, 0.72 for soybean, 0.55 for wheat and 13 lb per ton of alfalfa hay.
4. Subtract other sources. Take off phosphate supplied by manure, biosolids or the phosphate in any MAP or DAP already planned.
5. Divide by 0.46. The result is lb of TSP per acre. Adjust if the tag shows 44 or 45%.
6. Choose placement and timing. Broadcast and incorporate, or band near the row; Grove reports that surface, incorporated and banded TSP all deliver phosphate equivalent to the ammonium phosphates.

Worked example: a 180 bu per acre corn crop at 0.32 lb per bushel removes about 58 lb P2O5. To replace it you need 58 / 0.46 = about 126 lb of TSP per acre. An Ohio State on-farm study (2019) measured slightly higher removal, 0.35 lb per bushel for corn and 0.79 for soybean, and found a 180 bu corn and 60 bu soybean rotation removes 100-120 lb P2O5 per acre over the two years. Replacing 110 lb with TSP alone takes about 240 lb of product.

Typical maintenance rates by crop

Removal figures use Iowa State PM 1688 (2013) coefficients. Fields testing very low or low need more than removal to build the soil; follow your state’s build-up table.

0-46-0 fertilizer price compared with DAP

The World Bank tracks a monthly TSP price (spot, delivered into the US Gulf) in its Commodity Price Data “Pink Sheet”. The October 2026 edition (published 2 October 2026) gives TSP at US$690.0 per metric ton for September 2026, down from US$719.5 in July. DAP (spot, f.o.b. US Gulf) averaged US$800.6 per ton in September 2026. The annual TSP average rose from US$474.6 per ton in 2024 to US$577.6 in 2025.

Chart

TSP and DAP benchmark prices

US$ per metric ton; annual and quarterly averages

These are wholesale benchmarks for large cargoes. Retail prices at a farm dealer include freight, storage, blending and margin, so they are usually higher. Use the benchmark to watch the direction of the market and to compare products, and ask your dealer for a delivered quote.

Price per pound of phosphate, not per ton

Because TSP and DAP both carry 46% P2O5, a ton of each holds the same 920 lb of phosphate (per short ton) or 460 kg (per metric ton). At the September 2026 benchmarks, the phosphate in TSP cost about US$1.50 per kg P2O5 (690 / 460), against about US$1.74 for DAP. DAP also delivers 180 kg of nitrogen per tonne, so it is only the more expensive option if you would not otherwise buy that nitrogen. The calculator above lets you run the comparison with your own quotes.

Where the phosphate in TSP is mined

Every bag of TSP starts as phosphate rock, a sedimentary or igneous rock rich in the mineral apatite. The USGS Mineral Commodity Summaries 2026 estimates world mine production at 250 million tonnes in 2025, with China (110 million t), Morocco (36 million t) and the United States (20 million t) the three largest producers. Morocco holds by far the largest reserves, about 50 billion tonnes of the world’s 73 billion tonnes, according to the same USGS report.

Chart

Phosphate rock mine production

Million tonnes, 2025 estimate, largest producers

In the United States, five companies mined phosphate rock at 10 mines in Florida, Idaho, North Carolina and Utah in 2025, producing an estimated 20 million tons of marketable product worth US$1.9 billion (USGS, 2026). More than 95% of US rock went into wet-process phosphoric acid, the feedstock for MAP, DAP and TSP. The average mine value was about US$100 per ton in 2025, and the US relied on imports for about 16% of its apparent consumption.

Central Florida’s Bone Valley district, spread across Polk, Hardee, Hillsborough, Manatee and DeSoto counties, is the largest US source; the image at the top of this page shows that mining landscape from Sentinel-2. Mosaic operated three active mines there in 2024 (Four Corners, South Fort Meade and Wingate), according to its 10-K. For the state-by-state picture of where US minerals are mined, see our US mining map of active mines.

How phosphate rock is explored

Phosphate deposits are found by geological mapping, drilling and assaying rock for its P2O5 grade (the percentage of phosphate in the ore; phosphate rock typically holds 25-35% P2O5, per NCH-13). Satellite imagery helps at the screening stage by mapping exposed sedimentary beds, old workings and land cover before any field crew is sent. Our guide to exploring for iron ore, bauxite, phosphate and potash covers the methods, and Farmonaut’s satellite-based mineral detection service screens licence areas as exploration targets.

▶ How mining changes land, water and air, explained in clay with satellite maps. · 2:31

How to apply TSP without wasting phosphate

Phosphate does not move far in soil. It reacts with calcium in alkaline soils and with iron and aluminium in acid soils, becoming less available over time. Good practice aims to keep phosphate where roots will find it and on the field rather than in streams.

• Band or incorporate where erosion is a risk. Surface-applied phosphate on bare, sloping ground can wash off with sediment in the first heavy rain.
• Avoid frozen, snow-covered or saturated ground. Some US states restrict nutrient spreading in these conditions.
• Check soil pH. Kentucky Extension notes TSP and MAP do slightly better at a bulk soil pH of 6.0 and above, so lime acid fields first.
• Re-test every two to four years. Soil tests show whether build-up is working or whether you can drop to maintenance.
• Use variable rates where fields vary. Grid or zone sampling and yield maps let you put more product on low-testing areas and less on high ones.

Storage and handling

TSP granules pick up moisture from humid air, which causes caking and dust. Fertilizers Europe’s storage guidance recommends keeping bags on pallets off the floor, under cover and away from moisture, and keeping bulk piles in dry, covered sheds. Because the granules are acidic when dissolved, wash spreaders after use to limit corrosion.

What to check before you buy

• Guaranteed analysis. Confirm the P2O5 percentage on the tag (44, 45 or 46) and use it in your rate calculation.
• Granule size. For blending, the size guide number of the TSP should be close to that of the potash and urea it is mixed with, so the blend does not separate in the spreader.
• Delivered price per lb of P2O5. Divide the price per ton by the pounds of P2O5 in a ton (920 for a 46% product per short ton) and compare with MAP and DAP on the same basis, crediting any nitrogen you actually need.
• Metals data. Phosphate rocks differ in trace elements such as cadmium; ask the supplier for the product’s metals analysis if your buyers or regulator require it.
• Organic use. TSP is a synthetic product. The USDA technical review was prepared for a petition to the National Organic Program; check your certifier before using it on organic land.

▶ Remote sensing for mining in plain words: the instrument families used to screen ground for minerals such as phosphate. · 2:01

Frequently asked questions

What does 0-46-0 fertilizer mean?

It is the grade of triple superphosphate: 0% nitrogen, 46% phosphate (P2O5) and 0% potash by weight. A 50 lb bag holds 23 lb of P2O5.

What percentage of phosphorus is in TSP?

TSP 46 contains 46% P2O5, which equals about 20% elemental phosphorus (multiply P2O5 by 0.436).

What is triple super phosphate used for?

It corrects or maintains soil phosphorus where nitrogen and potash are not needed, for example before soybean or alfalfa, for fall phosphate ahead of spring crops, on pasture, and as the phosphate component of custom blends.

Is TSP the same as 0-46-0 and 00-46-00?

Yes. 0-46-0, 00-46-00 and “TSP 46” all describe the same product; the extra zeros are just a different way of writing the grade.

Is 0-46-0 the same as DAP?

No. DAP is 18-46-0: it has the same 46% phosphate but adds 18% nitrogen. TSP carries calcium instead of nitrogen.

How much TSP should I put per acre?

Divide the lb of P2O5 your soil test recommends by 0.46. For example, 60 lb P2O5 per acre needs about 130 lb of TSP.

Does triple superphosphate contain sulfur?

Very little. It is made with phosphoric acid rather than sulfuric acid, so unlike single superphosphate it is not a useful sulfur source.

Is TSP acidic?

The solution right around a dissolving granule has a pH of about 1 to 3.5 for a few days to weeks, but the effect on the whole field is small. Unlike MAP and DAP, it has no ammonium, so it does not acidify soil through nitrification.

Can I mix TSP with urea or potash?

Yes. University of Minnesota Extension reports no problems blending TSP with nitrogen, potassium or sulfur fertilizers. Match granule sizes and spread the blend soon after mixing.

Is triple superphosphate water soluble?

Mostly. About 85-95% of the phosphate in TSP is water-soluble (University of Wisconsin NCH-13), so it becomes available soon after it dissolves in moist soil.

What is the price of TSP fertilizer?

The World Bank benchmark for TSP, spot delivered into the US Gulf, was US$690.0 per metric ton in September 2026. Farm retail prices are higher once freight and handling are added.

Where does the phosphate rock for TSP come from?

China, Morocco and the United States mined the most phosphate rock in 2025 (USGS, 2026). In the US, rock comes from Florida, Idaho, North Carolina and Utah. For other questions about phosphate projects, use our mining query form or contact us.