Use Case: Variable-Rate Nitrogen (VRA) for Potatoes to Realize 5–10% More Yield

Use GeoPard with Sentinel-2 RedEdgeChlorophyll to create VRA N side-dress maps in potatoes and boost yield 5–10% with the same total nitrogen.

Read the full story: Realize 5–10% more yield in potatoes (case study)

Summary

Client: Databoerin (NL) — an innovative smart-farming consultancy led by Nicole Bartelds. They specialize in potato fertilization plans and have used GeoPard for several years to create variable-rate side-dress nitrogen based on Sentinel-2 RedEdgeChlorophyll and a crop growth model. Reported outcomes from multi-year fieldwork include 5–10% higher yield with the same total N, a more even canopy, and cleaner, more uniform ripening. A typical program uses ~60% base N early, then side-dress at crop closure guided by chlorophyll-derived N uptake.

Optimize side-dressing nitrogen in potatoes using Sentinel-2 chlorophyll (RedEdgeChlorophyll), a crop growth model, and GeoPard VRA prescriptions (ISOXML). Field results reported by a Dutch consultancy show +5–10% yield with the same total N, redistributed by need.

When to Use

• Potatoes on soils with variable mineralization or uneven vigor.

• Growers/consultants/dealers aiming to redistribute N at side-dress timing (row closure).

Data Inputs

• Satellite imagery: Sentinel-2; GeoPard processes cloud-free images within ~1 day, exposing RedEdgeChlorophyll.

• Field boundaries & zones: from farm/FMS or created in GeoPard.

• Optional: soil tests, prior yield, topography for context.

Agronomic Logic (Potatoes, N side-dressing)

• Base application: early season ~60% of the recommended dose (manure + mineral N).

• Side-dressing at crop closure: use chlorophyll-based N uptake to add N only where needed.

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Step-by-Step (GeoPard Workflow)

1. Ingest imagery Use the latest cloud-free Sentinel-2 scene. GeoPard provides RedEdgeChlorophyll for each field.

2. Estimate N uptake From chlorophyll content (proxy for N in leaves) estimate current N uptake vs. optimal uptake from the crop model.

3. Compute the delta Convert the gap to variable rates (kg N/ha) per management unit.

4. Create the VRA map. Use the Rates Distribution Tool Set min/max rates and operational constraints, then export ISOXML for the spreader/terminal.

5. Apply & verify Execute side-dressing; monitor canopy evenness and later yield. Use as-applied + new imagery to validate.

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Outputs

• RedEdgeChlorophyll map (canopy N proxy).

• VRA N side-dressing prescription (ISOXML).

• Optional EVI2 to visualize variety-driven differences and canopy evenness.

Expected Impact

• Yield: reported +5–10% with unchanged total N, thanks to better spatial allocation.

• Crop uniformity: more even canopy → more uniform phytophthora protection and ripening.

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Best Practices

• Time side-dressing around crop closure.

• Exclude headlands/borders; set rate floors/ceilings for machine safety.

• Watch clouds & shadows; confirm units (kg/ha).

• If manure mineralization is high, keep conservative max rates and validate with test strips.

Validation & KPIs

• Canopy evenness (post-application imagery)

• Yield uplift by zone vs. baseline.

• Nitrogen Use Efficiency (NUE) and % of area within the target rate band.

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Troubleshooting

• No recent imagery? Wait for next cloud-free pass; re-run the map.

• Patchy vigor due to variety? Use EVI2 to separate variety effects from N signal.

• Controller rejects file? Re-export ISOXML; check terminal profile & coordinate system.

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FAQ

Which index is used? RedEdgeChlorophyll for N status; EVI2 for vigor/variety contrasts.

How much base N vs. side-dress? Typical pattern in this workflow: ~60% base, remainder at side-dress informed by chlorophyll.

What uplift to expect? Field experience cited: +5–10% yield with the same total N, redistributed. Results vary.

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Attribution

Use-case adapted from a project with Databoerin (NL) using GeoPard analytics for potato fertilization.