Zone Forge — Precision Agriculture you can verify

The literature

Built on the published work of the land-grant system.

40+ land-grant extension publications across all 50 states — cited on every rate.

Penn State AASL UDel Adams-Evans Iowa State PM 1688 Tri-State 2020 UGA Circular 874 Cornell NMSP UF/IFAS SS163 MSU Nutrient Guidelines UT W229 / SP763 OSU EM-9585 (Oct 2025) WSU FS398E (Jun 2025) UVM BR 1390.3 UNL G1504 Auburn ANR-0006 UMD SFM-5 UIUC Agronomy Handbook Clemson Moore-Sikora UK AGR-1 (2025-26) Mallarino 1995

All 40+ publications

Pick your state — your recommendation cites your state's land-grant publication, not a national average. Try the free lime calculator →

01The problem with precision ag

Most tools ask you to trust the algorithm. We show you ours.

Black-box recommendations. Hidden formulas. No way to check them against your own soil tests. And mismatched extractant methods that silently bias rates by 20–40 lb per acre.

Farmers deserve software that shows its work — not software that asks for blind faith.

// Zone Forge shows its work

# P₂O₅ for corn — hybrid philosophy
# soil-test P = 25 ppm (Mehlich-3)

source  = "Tri-State 2020"
goal    = 200   # bu/ac corn
target  = 30    # ppm
removal = 0.37  # lb P₂O₅ / bu
factor  = 10    # lb P₂O₅ / ppm
years   = 4     # buildup window

# maintain band 27–33 ppm
# soil 25 < 27 → BUILD
deficit = target - soil = 5
buildup = deficit * factor / years
        = 12.5
rate    = goal * removal + buildup
        = 86.5 lb P₂O₅ / ac

# to product — DAP (18-46-0)
dap     = 86.5 / 0.46 = 188.04 lb/ac

✓ Tri-State 2020 — cited

This is the actual calculation — every input named, every step printed, source cited.

02Don't trust us — check us

Every number Zone Forge prints is auditable.

We don't ask you to trust an algorithm.

Read the formulas, check the source, reproduce them on the back of an envelope.

If you can't, we haven't done our job.

Published, cited tables. Every recommendation traces to a named extension publication with a calibration year.
Deterministic formulas. Same inputs, same rate — no machine-learning black boxes. Anything we infer instead of cite is marked verified: false, and stale or sparse data gets a warning with context, never silently swallowed.
Printable field reports. One-page PDF with map, per-zone table, sources, and your inputs — hand it to your agronomist, retailer, or banker.

Read the methodology

FIG. 1 — Sample field report · Carter North 80

Field

Carter North 80

Acres

84.2

Source

Tri-State 2020 (M3)

Philosophy

Hybrid · Buildup 4 yr

Yield goal

200 bu/ac corn

Product

DAP (18-46-0)

Zone	Rate	Acres	$/ac
Very Low	220	8.4	$83.60
Low	175	14.2	$66.50
Optimum	130	31.8	$49.40
High	85	22.6	$32.30
Very High	0	7.2	$0.00

03What you get

From the sample bag to the spreader — with the formulas showing at every step.

Calibrated, not averaged

50-state extension calibration

Pick your state — Zone Forge auto-resolves the right calibrated source. Penn State Mehlich Buffer, UDel Adams-Evans, Iowa PM 1688, Tri-State 2020, OSU's October 2025 Sikora tables, and 30+ more land-grant publications. Every critical level and removal factor cites your state's published extension paper.

Your stateIowa ▾

SourceIowa State PM 1688

ExtractantMehlich-3

PhilosophyBuild & maintain

✓ calibrated source resolved

Plain English

Graded soil-health report card

Upload a soil test and see your worst nutrients first — graded in 26 states in your own state university's rating words; the rest show your honest measured values. pH and lime are calibrated for all 50 states. We never print a wrong grade.

P — Very Low K — Low pH — Optimum

No silent drift

Extractant enforcement

Auto-detects whether your lab used Mehlich-3, Bray-P1, or Olsen — and refuses to mix them silently. No more 20–40 lb/ac drift from mismatched calibrations.

✓ Mehlich-3 detected ✓ Olsen supported ✗ Bray-P1 mix — blocked

By field, by the hour

Spray-window advisory

Each field gets a plain-language read from its own forecast — wind and gusts, Delta-T, rain, rainfast risk, NWS alerts. An advisory to help you plan; your eyes still make the call.

● Good to spray — until 7 pm

Wind6 mph, gusts 9

Next windowTomorrow 9 am

Local bids, not a national number

Local cash bids on your crop

Tap the crop on your field map and see today's USDA local cash bid for your area. Contract or specialty crop with no public bid? Set your own price once in the Price Book.

Corn$4.12 / bu

SourceUSDA AMS · local bid

One wizard pass

One pass, three prescriptions

Enter a litter analysis, pick P-demand or N-demand, set caps. The engine sizes litter, subtracts the K and N credits per zone, and ships three shapefiles. Or blend two or three products in one pass — edit any input and every layer recomputes.

01Litter — t/ac sized to demand

02Potash — K credit subtracted

03Nitrogen — N credit subtracted

The radio's job, in your pocket

Team chat with field context

Talk to your crew inside the app. Drop a field card into a bubble — they see its shape, acres, crop, and Rx-readiness without leaving the message. Voice messages, group chats, "at North 80" presence.

Can you spread the North 80 this week?

Rx is ready — sending it over.

North 8084.2 acCorn✓ Rx ready

Past the "samples collected" banner

Sample-to-lab kit

Other tools end at the "all samples collected" banner. Zone Forge gets your samples to the lab: QR-coded bag labels printed at home, six US labs to pick from, a pre-filled submission form, a UPS or FedEx Ground label billed to your own account, and a notification when the cooler arrives. Five minutes instead of forty.

How the lab handoff works

LabelsQR zone labels · printed

Formpre-filled for your lab

Shippinglabel created · tracked

✓ arrived at lab

Also in the box Click-to-reassign zones Three rate philosophies Printable field reports See all features

04The workflow

From soil report to applied rate in four steps — five if we handle your lab shipping too.

Upload your soil samples

Drag in a CSV from your lab. Zone Forge auto-detects lat/lon, pH, P, K, organic matter, CEC, and any micronutrient columns. Visualize as points, heatmap, or hotspot — clipped to your field boundary.

Pick your source & philosophy

Choose the regional table that matches your lab method. Pick Sufficiency for cheap rented ground, Build-and-Maintain for owned acres, or Hybrid for a balanced approach.

Review and adjust zones

See five color-coded zones with product rates, acres, and live cost-per-acre. Tap any contour to reassign it. Edit rates inline. Field totals update on every keystroke.

Push to your platform

One tap exports a validated shapefile to your platform. Live status polling. If the platform's API hiccups, your Rx stays safe locally and you retry with a single button.

See the full workflow →

05Into the cab

Built for the equipment you already own.

No thumb drives, no email-the-dealer. Your prescriptions show up on your display, ready to apply — Zone Forge talks to your operations platform through its official APIs, with sign-in, token refresh, and the four-step upload handled for you.

OAuth 2.0 with 365-day refresh — sign in once, stay signed in
Auto-validates shapefile schema before upload (Rate field, polygon geometry, EPSG:4326)
Live upload status — QUEUED → VALID with retry on partial failure
Soil heatmaps and prescriptions both supported — full platform visibility
If the platform's API hiccups, your Rx stays safe locally — retry with one tap

FIG. 2 — Upload pipeline · live status

✓ POST mapLayerSummaries 204ms

✓ POST mapLayers (legend + extent) 187ms

✓ POST fileResources 142ms

✓ PUT shapefile.zip (binary) 1.2s

● Polling validation status… VALID

Connections

Connect your equipment account once — your fields and boundaries pull in automatically, and your variable-rate prescriptions push back to the cab.

Connects with John Deere Operations Center

Live

PTx FarmENGAGE Fendt · Massey Ferguson · Valtra · Challenger Coming soon

CNH FieldOps Case IH · New Holland Coming soon

Precision Agriculture
you can verify.