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 -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: +5–10% yield with the same total N, more even canopy, and cleaner, more uniform ripening. Typical program: ~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.
Step-by-Step (GeoPard Workflow)
Ingest imagery Use the latest cloud-free Sentinel-2 scene. GeoPard provides RedEdgeChlorophyll for each field.
Estimate N uptake From chlorophyll content (proxy for N in leaves) estimate current N uptake vs. optimal uptake from the crop model.
Compute the delta Convert the gap to variable rates (kg N/ha) per management unit.
Create the VRA map, Use Rates Distribution Tool Set min/max rates and operational constraints, then export ISOXML for the spreader/terminal.
Apply & verify Execute side-dressing; monitor canopy evenness and later yield. Use as-applied + new imagery to validate.
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.
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 % area within target rate band.
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.
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.
Attribution
Use-case adapted from a project with Databoerin (NL) using GeoPard analytics for potato fertilization.
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