Soil sample to applied rate, in five steps.

The twenty minutes other tools leave you to do alone.

If you're doing your own soil sampling, the workflow before Step 1 — bag the samples, label them, fill out the lab's intake form, pack the cooler, drop at the carrier, wait — is where most tools just hand you a Sharpie and a stack of Ziplocs. Zone Forge picks up here.

• Print Avery 5160 or 5163 sticker sheets with a QR code on every label. Each carries the sample ID, grid cell, plan name, field name, and date. Stick on Ziplocs before you head out — no more hand-writing 57 IDs in a windy field.
• Tap “Bag it” in the field after each sample. Voice-dictate observations (free, via your browser's speech recognition). Reprint a single label if one tears.
• Pick from six US labs — Waters Ag, A&L Great Lakes, Ward, Spectrum, Midwest, Brookside. Zone Forge generates the lab's submission form (pre-filled) plus a one-page shipping manifest for the top of the cooler.
• Buy a UPS or FedEx Ground label in-app, billed to your own carrier account. Zone Forge takes no per-label fee. Compare rates across carriers before you commit; address typos are caught by the carrier's validation API before you spend.
• Get an email + push notification when the lab receives the cooler. Tracking is live on the plan the whole way.

Connect your fields and upload soil samples.

Sign in with your platform — Zone Forge pulls your organization, fields, and boundaries automatically. Then drop in a soil-test CSV from your lab.

Zone Forge auto-detects which columns are which: latitude and longitude, pH, P, K, organic matter, CEC, and any micronutrient values your lab reports. It also detects the phosphorus extractant from the column header or lab name. If it can't, it asks you once — and remembers your answer for next time.

Once your fields are connected, the field view does more than soil: the crop tag shows your local USDA cash bid — a live local price, not a futures quote (growing a contract crop with no public bid? set your own once in the Price Book) — and a field-aware spray-window advisory reads the field's own forecast to tell you, at a glance, whether it's a good hour to spray. Both are advisory, and both are right there on the field screen.

Get a graded report card.

The moment your test is in, Zone Forge grades it — before you draw a single zone.

Each nutrient gets a plain-word verdict, worst first, coded by both color and word (never color alone), so on a phone in the field you see the one thing to fix first at a glance. You also get variability hints where a field is patchy and a fertility trend across your past uploads. In 26 states we grade in that state university's own rating words — Arkansas reads "Very Low" to "Above Optimum," Delaware reads its Fertility Index Value. In the rest, we honestly show your measured values with a note on why we don't grade that lab format yet; pH and lime are calibrated for all 50 states.

See your soil at field scale.

Switch between four visualization modes to understand your samples before you commit to a prescription.

• Points mode. Each sample as a colored dot, bucketed into five quantile bands so all colors always show — no all-yellow fields.
• Heatmap mode. Inverse-distance-weighted interpolation with eight nearest neighbors, power 2, in projected UTM coordinates. Renders at roughly one-acre cell resolution.
• Hotspot mode. Density clustering to see where high-value zones cluster.
• Off mode. Hide soil viz to inspect the prescription overlay cleanly.

Everything clips to your field boundary. If part of your field is outside the convex hull of your samples, Zone Forge flags it — that's where the engine is extrapolating, and you should know.

Pick your source, philosophy, and product.

Three decisions, all explicit, all overridable. Defaults are conservative.

Source

Pick your state. Zone Forge auto-resolves the calibrated source from a library of 40+ land-grant extension publications: Penn State AASL for PA, UDel Fertility Index Value (Mehlich-3) for DE, UGA Circular 874 for GA, OSU EM-9585 (October 2025) for OR, MSU Nutrient Guidelines for MS, UT W229/SP763 for TN — every state has a calibrated source mapping. Each is peer-reviewed extension literature, calibrated to a specific phosphorus extractant. Zone Forge will refuse to run if your samples don't match — unless you opt in to a published cross-extractant conversion (Mallarino 1995 for Bray↔M3, OSU ANR-75 for Olsen).

Philosophy

Hybrid is the default — a true 3-zone system. It builds low-testing areas with a deficit-scaled buildup so adjacent variable-rate zones get genuinely different rates, holds at crop removal in the target band, and reduces fertilizer on high-testing zones according to your above-target strategy: hold fertility, slowly reduce high areas (default), or mine down expensive nutrients. The maintenance tolerance band and exact drawdown multipliers live under Advanced for anyone who wants to tune them. Sufficiency applies only what the crop will remove this season — best for short-tenure ground. Build-and-Maintain brings every acre up to target over a configurable horizon (default four years), then maintains.

Product

Pick the fertilizer you actually plan to spread. DAP, MAP, urea, UAN-32, KCl, ag lime — Zone Forge converts the recommended nutrient rate into the equivalent product rate using the published analysis (e.g., DAP 18-46-0 → divide P₂O₅ rate by 0.46 to get pounds of DAP per acre).

Spreading more than one nutrient? Open the Blend wizard instead of running the single-product creator once per nutrient — Zone Forge can output a separate variable-rate layer per product (the default, one pass each) or one blended bag at a single field-wide ratio and variable total rate for a single-bin spreader, whichever your equipment runs. See how blends work.

Five zones. Click to reassign. Live cost updates.

Every prescription comes back with five color-coded zones — Very Low, Low, Optimum, High, Very High — mapped to product rates from the agronomic table.

You're not stuck with the algorithm's first guess. Tap any contour on the map to bump it to a different zone. The shape preserves; only the rate and color change. The field total and per-zone cost-per-acre update on every keystroke.

Want to override a rate entirely? Tap the rate field and type. Manual edits are saved alongside the prescription so future regenerations don't blow them away.

Push to your platform. Or take it to the tractor on a USB.

One tap exports a validated shapefile to your operations platform. With John Deere connected, it lands on both surfaces at once — a Map Layer you can view in Operations Center and an entry in the in-cab Files tab, selectable for Wireless Data Transfer straight onto the tractor. Live status polling shows the upload progressing through QUEUED to VALID.

Running an older in-cab display without over-the-air transfer, or a non-major brand? Same shapefile, downloaded straight to your browser. Drop it on a thumb drive and load it onto the tractor the same way you always have. No platform connection required.

If the platform API hiccups — and it does, occasionally — your prescription stays safe locally. The retry button re-runs the four-step upload pipeline against saved data without re-doing the work. No dead ends.

Print a one-page field report at the same time: header, source, product, map thumbnail with sample-point overlay, per-zone table with rates and costs, cost totals. Hand it to your applicator, retailer, or banker.