Product · Prescriptions
Seed, fertilizer and lime prescriptions.
Each prescription starts from the field’s own soil tests and zone map. Fertilizer and lime rates are computed by tools from published guidelines. Seed rates are the grower’s own numbers, set zone by zone.
Seed · live since July 2026
Seed
- Inputs
- A hybrid and a target population (seeds per acre, or per hectare outside the US), with an optional population for any zone.
- How rates are set
- The grower sets them; no table sets seed rates. Fieldhand applies the grower’s population to every zone unless a zone has its own, and checks each one falls between 1,000 and 80,000 seeds per acre. Setup happens in the conversation.
- Zones or one rate
- Zones come from the field’s zone map. If every zone ends up with the same population, the prescription is written as one whole-field rate.
Fertilizer · P and K by zone
Fertilizer
- Inputs
- The field’s soil test, the crop and yield goal, and crop removal. An unknown removal is treated as unknown, never as zero.
- How rates are set
- Computed by tools from the regional guideline for that field, such as Iowa State PM 1688: a build-and-maintain approach (crop removal plus a build increment) or a sufficiency approach. Accounts that include custom protocols can adapt a published guideline into their own.
- Zones or one rate
- Zone rates are used only when zones exist, the soil test is current and the zone map clears a confidence floor. Otherwise the field gets one conservative rate.
Lime
Lime
- Inputs
- Soil pH, the lab’s buffer pH when there is one, the target pH and the lime product’s ECCE.
- How rates are set
- With a measured buffer pH, the requirement comes from the buffer-pH method (SMP by default). Without one, a formula from measured pH, adjusted for ECCE and depth, is used. The default target pH is 6.2. A modeled buffer pH never sets a rate.
- Zones or one rate
- Variable-rate lime is recommended only when the zones are actionable. Otherwise Fieldhand flags that one rate is the safer call.
Zones or one rate
A zone rate has to earn its place.
Before Fieldhand recommends zones, it checks on held-out samples whether they beat a single field-average rate. If they don’t, it recommends a single rate and says why.
See the method and a worked example in Research.
- Zones must exist for the field.
- The soil test must be current: a mobile nutrient tested more than four years ago gets one rate.
- The zone map must clear a confidence floor.
- If every zone ends up with the same rate, the prescription is written as one rate.
Export
Out to the equipment.
An approved prescription can be exported in these formats. Export depends on the account’s plan.
Seed and fertilizer
Shapefile, ISOXML, PDF and GeoJSON, plus packages formatted for John Deere (USB), Trimble, Case IH, Topcon, FieldView and AGCO / Fendt displays.
Lime
Shapefile, CSV and PDF.
Draft your first prescription.
Create a free account, add a field and its soil test.