Map Fertilizer Analysis: Potash & MAP Pricing, Rates, ROI

Reviewed August 2026 against USDA NASS, USDA AMS, and USGS Mineral Commodity Summaries.

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Map fertilizer analysis is the practice of pairing spatially referenced soil and yield data with current potash and MAP (monoammonium phosphate) pricing so that every zone of a field gets only the nutrient it actually needs. As of August 2026, potash (MOP, 0-0-60) is trading at $497.50/ton spot in Illinois and $490–$505/ton across the US Corn Belt, while MAP is running $890/ton in North America and DAP $912.22/ton in the Corn Belt — high enough that a 10–15% reduction in blanket over-application, the typical gain from zone-based rather than field-average rates, is real money on any farm over a few hundred acres. This page walks through the pricing, the application-rate benchmarks USDA publishes, the mapping method itself, and where potash and MAP diverge in how they should be handled spatially.

What This Article Covers

• Current potash and MAP fertilizer prices, and where to check them for yourself
• USDA application-rate benchmarks for map-based prescriptions
• How map fertilizer analysis actually works — the method, not just the concept
• Potash vs. MAP fertilizer analysis: a side-by-side comparison
• A savings calculator for zone-based vs. flat-rate application
• Where the data runs out, and how to fill the gap for your own field
• Farmonaut’s satellite-based tools for mapping mineral and nutrient zones
• FAQs

Potash Fertilizer Analysis: Current Pricing and Consumption

Potash (potassium chloride, or muriate of potash, 0-0-60) supplies potassium for enzyme activation, water regulation, and disease resistance. Its spot price in Illinois was $497.50/ton in July 2026 per USDA AMS Production Cost Reports, and farmdoc daily at the University of Illinois reported the broader US Corn Belt range at $490–$505/ton heading into fall 2026 — both figures reflecting fertilizer and fuel costs that moved higher into the season. Full detail, updated roughly every two weeks by USDA AMS, is available directly from the source:

USDA AMS Production Cost Reports (Illinois) and farmdoc daily, August 2026 both publish current regional spot prices — check them directly rather than relying on a fixed number, since USDA AMS refreshes these every two weeks and prices in fall 2026 already differ from a July reading.

At the national scale, the USGS Mineral Commodity Summaries 2025 puts US potash consumption at 5,900 thousand metric tons (K₂O equivalent) for 2025, with US potash sales valued at $550 million that year. Potash is also the fertilizer with the biggest import dependency in this analysis: Canada supplied 79% of US potash imports in 2025, according to the same USGS report — a concentration worth knowing if you’re forecasting price risk, since almost any supply disruption on that single corridor moves the US spot price. USGS republishes this summary annually each March, so the 2025 figures will be superseded by a 2026 edition at pubs.usgs.gov under the mcs2026 filename once it posts.

On usage share, USDA NASS’s most recent Agricultural Chemical Use survey (2015, the latest full pass on this metric) found potash (K₂O) accounted for 22% of total fertilizer nutrient usage nationally. NASS runs this survey biennially in an off-year cycle, with the next update covering 2025 data expected around 2027 — check USDA NASS’s Chemical Use program page or the Quick Stats database directly for the current release and state-level breakdowns.

MAP Fertilizer Analysis: Current Pricing and Yield Response

MAP (monoammonium phosphate, 11-52-0) combines phosphorus and ammonium-nitrogen, which is what makes it a strong “starter” fertilizer for root development in the first weeks of growth. North American spot price for MAP was $890/ton in August 2026 per Procurement Resource’s market tracking, while the CIF Germany price — a useful benchmark for reading European supply pressure back into the US market — was $793.89/ton in July 2026. DAP (diammonium phosphate), the other common phosphate source, was $912.22/ton in the US Corn Belt in August 2026 per farmdoc daily. These three numbers moving together is itself informative: when DAP trades above MAP by more than a few percent, it’s usually a signal of tightness in the ammonia side of the phosphate complex rather than the phosphate rock side.

Procurement Resource updates MAP pricing by region on a quarterly to monthly cadence — see their MAP Price Trends page for the current North America, Europe, China, Brazil, and Australia figures side by side.

On agronomic return, Mosaic Crop Nutrition’s agronomic research (drawing on multiple field studies) documents a typical 20% yield improvement from MAP application versus an untreated control. That figure is a controlled-trial result, not a guarantee for any specific field — soil P status, crop, and placement method all move the outcome — but it’s the only quantified, sourced yield figure available for MAP specifically; see Mosaic Crop Nutrition’s MAP resource page for the underlying studies.

On volume, US phosphate fertilizer consumption was 739,000 tons in 2024 per IndexBox’s analysis of USDA data. That figure covers phosphate (P₂O₅) in aggregate — USDA does not break out consumption by product form, so a MAP-specific national tonnage, separate from DAP or triple superphosphate, is not published. If you need a MAP-only volume estimate for a specific state or region, the closest available proxy is USDA NASS’s Agricultural Chemical Use Program, which reports phosphate application rates and treated acreage by crop and state, even though it does not separate MAP from other phosphate sources.

Application Rates: The USDA Benchmark for Map-Based Prescriptions

Before a map fertilizer analysis can flag a zone as over- or under-applied, it needs a benchmark to compare against. USDA NASS’s Agricultural Chemical Use Program is that benchmark for US field crops: phosphate application rates for major field crops have held in a 25–36 lb/acre/year range since the late 1960s, a level of stability that itself tells you something — most of the gains left in phosphate management now come from where and when it’s placed within a field, not from raising or lowering the average rate. Potash’s 22% share of total nutrient usage (2015 NASS survey, described above) is the complementary figure: it tells you how much of the total fertilizer bill on a typical operation is potassium rather than nitrogen or phosphorus.

These are the two figures a zone map should be checked against: if your variable-rate prescription is putting significantly more than 36 lb/acre of phosphate on your best-performing zones, or applying potash at a rate wildly out of line with what a 22%-of-total-nutrient-budget farm would spend, that’s worth a second look before the applicator runs. NASS’s Chemical Use survey guide has the current state-level detail; check it directly since it updates on the biennial cycle described above.

Core Components of a Map Fertilizer Analysis

A map fertilizer analysis is not a one-time soil test. It’s an ongoing process with three linked pieces, each of which has to be right for the output prescription to be trustworthy.

1. Soil Sampling and Analytics

• Grid or zone-based sampling: systematic sampling establishes a baseline for N, P, K, micronutrients, pH, and organic matter across defined management zones rather than a single field average.
• Lab analytics: labs quantify extractable nutrient pools, cation exchange capacity, and salinity — the inputs a prescription model actually runs on.
• Temporal tracking: repeat sampling on a fixed interval (commonly 2–4 years) tracks how nutrient levels shift with cropping history and prior fertilizer applications.

2. Spatial Data Integration

• GIS layering: soil test results, topography, drainage, historic yield, and satellite vegetation indices (NDVI) are overlaid to build a nutrient variability map.
• Visualization: surplus and deficiency zones become visible on the map rather than buried in a spreadsheet, which is what makes the variable-rate prescription actionable in the cab.

3. Fertilizer Recommendation Frameworks

• Map-based prescriptions: spatial data and crop-specific agronomic targets (like the USDA 25–36 lb/acre phosphate benchmark above) translate into a variable-rate file for each zone.
• Dynamic models: crop type, growth stage, and input compatibility adjust the recommendation rather than applying one static rate map season after season.

Potash vs. MAP Fertilizer: Side-by-Side for Zone Mapping

Potash and MAP solve different agronomic problems and need to be mapped differently. The table below sets out how they diverge across the variables that actually change a variable-rate prescription.

The Mapping Method: How to Build a Prescription That Holds Up

The method itself is what stays useful once these prices move — and they will. Here’s the sequence a defensible map fertilizer analysis follows, regardless of what potash or MAP cost in the season you’re reading this:

1. Pull the current spot price for potash and MAP/DAP from USDA AMS Production Cost Reports (updated every two weeks) or farmdoc daily, rather than working off a number from a prior season.
2. Check the current USDA NASS application-rate benchmark for your crop and state via the Chemical Use survey — remember this only refreshes on a roughly two-year cycle, so the most recent published figure may be one or two seasons old.
3. Grid or zone-sample the field at a density fine enough to resolve the yield and topography variability you can already see in historic yield maps or NDVI imagery.
4. Overlay soil test results with GIS layers — topography, drainage, and remote-sensing indices — to separate surplus zones from deficiency zones.
5. Generate a variable-rate prescription that applies potash and MAP as two independent rate maps, not one blended nutrient budget, since they answer to different agronomic and environmental risks (leaching for K, runoff and fixation for P).
6. Validate with ground-truth sampling before committing the full field to the prescription — sparse or stale sampling is the single most common source of a map that looks precise but isn’t.

Zone-Based vs. Flat-Rate Savings Calculator

Use your own field size and current potash/MAP prices to see what a 10–15% reduction in over-applied acres — the typical range from replacing a flat field rate with a zone-based prescription — is worth in dollars before you commit to the mapping investment.

Assumes a 2,000 lb ton and applies the reduction percentage against total flat-rate spend; it does not include application equipment costs, soil sampling costs, or yield-side returns from better-placed nutrients. Prices are the August 2026 spot figures cited above — update the dropdown with your own current quote from USDA AMS or your supplier before relying on the output.

Applied Across Agriculture, Forestry, and Mining Reclamation

Map fertilizer analysis isn't confined to row crops. The same GIS-plus-sampling method extends to three other land types:

In Agriculture

• Soil-specific lime and micronutrient zoning: corrects pH and trace-element deficiencies precisely where a zone needs it.
• Phosphorus placement: applies MAP or DAP only in critical root zones, cutting fixation and runoff to field edges and waterways.
• Potash zoning: concentrates potassium application away from sandy or high-leaching-risk zones identified in the soil map.

Forestry

• Nursery and reforestation: targeted fertilizer pulsing boosts seedling survival in low-fertility or drought-prone zones.
• Drainage and erosion prediction: topography and drainage maps support long-term forest health planning.

Mining and Reclamation Sites

• Soil restoration: identifies and amends extreme pH, compaction, or depleted nutrient pools post-mining ahead of vegetation establishment.
• Erosion and buffer control: maps compaction and instability to guide cover-crop and buffer planting.

Where the Data Runs Out — and How to Fill It for Your Own Field

Being direct about the limits of what's publicly available is more useful than papering over them with a hedge word. Five things a map fertilizer analysis often wants that are not currently published in a form specific enough to cite:

• MAP vs. DAP vs. triple superphosphate US consumption, broken out by product: USDA reports phosphate (P₂O₅) consumption in aggregate only. To estimate MAP's share for your region, ask your regional fertilizer retailer or co-op for their MAP-vs-DAP mix, since that ratio isn't in a government table.
• MAP-specific per-acre rates for corn and soybean: USDA NASS publishes the general phosphate rate (25–36 lb/acre/yr) but not a MAP-only figure. A university extension soil-test lab in your state can convert your soil-test P level into a MAP-specific recommendation for your crop.
• Controlled MAP-vs-DAP yield trials under identical US field conditions: the 20% figure above is MAP-vs-untreated, not MAP-vs-DAP. If you need that specific comparison, a side-by-side strip trial on your own field, run for at least one season, is the only reliable source — no published dataset currently answers it directly.
• State-level phosphorus runoff or application limits: these are set at the state or watershed level, not federal, so check your state department of agriculture or environmental agency for the rule that applies to your county.
• Multi-year MAP and potash price forecasts: no commodity-specific forecast to 2030 was located for this article. For a live view, USDA AMS's biweekly reports and farmdoc daily's ongoing coverage are the closest thing to a running forecast, since both track the trend as it happens rather than projecting it.

Economic and Environmental Implications

Economic Viability

At $497.50/ton potash and $890/ton MAP (August 2026 spot), a 500-acre farm applying 150 lb/acre of either fertilizer flat-rate is spending roughly $18,650 (potash) or $33,375 (MAP) on that pass alone — the calculator above lets you run your own acreage and price against a 10–15% zone-mapping reduction. Given USGS's $550 million total US potash sales figure for 2025, the scale of spend this analysis addresses nationally is not trivial even before mapping technology enters the picture.

Environmental Stewardship

• Runoff and leaching mitigation: zone mapping concentrates K and P placement where crops can use it, cutting the loss to water that flat-rate application allows in low-need zones.
• Regulatory alignment: state-level nutrient management plans increasingly expect zone-level, not field-average, justification for application rates — a documented map fertilizer analysis is the record that supports it.

Farmonaut's Role: Satellite-Based Intelligence for Land, Mining, and Nutrient Mapping

Farmonaut supports agriculture, forestry, and mining-adjacent land management through satellite-based analytics and remote sensing. Beyond crop monitoring, the platform delivers actionable intelligence for mineral exploration, soil reclamation, and nutrient mapping.

• Satellite-driven 3D mineral prospectivity mapping: explore our 3D mapping solution for early exploration and environmental planning.
• Satellite-based mineral detection: our satellite platform uses hyperspectral and multispectral data to identify minerals and inform reclamation-site nutrient strategy.
• Dedicated mining queries: for mineral detection and nutrient restoration analysis, connect via our Get Quote page.
• General inquiries: for consultation or strategic support, Contact Us.
• Background on potassium's agronomic role is covered in our potash benefits guide.

Frequently Asked Questions

Conclusion: Prices Change, the Method Doesn't

The numbers in this article — $497.50/ton potash, $890/ton MAP, 79% Canadian import share, 25–36 lb/acre phosphate rates — will all move. USDA AMS refreshes spot prices every two weeks, USGS republishes its potash summary each March, and NASS's application-rate survey runs on a roughly two-year cycle. What doesn't expire is the method: pull the current price, check the current USDA benchmark, sample the field at real density, layer the GIS data, and map potash and MAP as two separate nutrient problems rather than one blended budget. That sequence is what turns a soil test into a defensible variable-rate prescription in any season you run it.

• Potash (MOP): $497.50/ton Illinois spot, August 2026 — USDA AMS.
• MAP: $890/ton North America spot, August 2026 — Procurement Resource.
• Canada supplied 79% of US potash imports in 2025 — USGS.
• US phosphate application rate: 25–36 lb/acre/yr since the late 1960s — USDA NASS.
• MAP yield response: ~20% vs. untreated control — Mosaic Crop Nutrition.

For a tailored zone-based fertilizer or mineral analysis, map your site with Farmonaut now.