How the Atlas reaches an answer — and what's a placeholder.

The Atlas Tool combines what the PNW Biochar Atlas exposes as six separate tools — Soils Data Explorer, Biochar Property Explorer, Selection Tool, Amendment Rate, Cost-Benefit, and the CPS 336 implementation tools — into a single 5-step workflow:

1. 01Site & soil — map click loads SSURGO, or manual lab entry
2. 02Use case & priorities — crop or use-case context, top three priorities
3. 03Recommended biochars — ranked by weighted points across priorities
4. 04Rate & cost — application rate, acreage, cost-benefit, carbon storage
5. 05Review & report — printable NRCS-ready report

State persists across steps and the user can jump backward at any time. The same priorities and weighted-points approach published by the PNW Atlas drives the ranking — making side-by-side comparison with that prior art straightforward for ABI evaluators.

• Site & soil. A map click resolves the dominant SSURGO map unit at that point via USDA's Soil Data Access REST service and pulls dominant-component surface-horizon properties (texture, pH, organic matter, CEC, bulk density, available water capacity, Ksat, drainage class, taxonomic order). A second SDA query returns the polygon geometry so the user can see exactly which map unit they're inside. Manual lab entry overrides SSURGO. Five preset sample sites let evaluators bypass map navigation entirely.
• Use case context. 26 crops with N/P/K targets and preferred pH range, plus carbon-project, compost co-application, and research / field-trial use cases. Each non-crop use case includes 3 suggested priorities drawn from published biochar literature. The data structure can absorb additional categories (stormwater, remediation, restoration, urban landscape) when ABI's analytical data and algorithm coverage are ready to support them.
• Soil-health priorities. Up to 3 priorities ranked by importance. 13 goals available: water retention, raise pH, increase CEC, immobilize heavy metals, reduce nutrient leaching, sequester C, soil aggregation, increase OM, improve drainage, supply N / P / K, and co-apply with compost.
• Biochar materials. 30 biochars across 14 feedstocks with feedstock, pyrolysis temperature, pH, EC, CEC, BET surface area, fixed/volatile/ash carbon fractions, H:Corg ratio, total N/P/K/Ca, particle size, pore diameter/volume, bulk density, IBI classification, supplier coordinates, and price. In production this is fed by ABI's analyzed biochars and supplier-validated analytics.
• Scenario parameters. Application rate, acreage, biochar cost per ton, NRCS incentive rate, and compost co-application flag.

Per RFP §4, ABI and USDA ARS will provide all suitability algorithms. The prototype implements transparent placeholder logic in two layers:

• Weighted-points ranking. For any combination of up to 3 priorities, biochars are ranked using exactly the PNW Atlas's National Biochar Selection Tool scheme: priority 1 awards 15-11 pts to the top five biochars, priority 2 awards 10-6 pts, priority 3 awards 5-1 pts. Biochars matching multiple priorities accumulate points. The mapping from each goal to a biochar property is drawn from the published PNW Atlas logic (e.g. "carbon sequestration → lowest H:Corg ratio").
• Per-goal 0-100 scoring. Once a biochar is selected, each priority returns a 0-100 score plus driver and caution strings. Drivers explain why the score went up; cautions explain limiting factors. Both surface in the report — making substitution of peer-reviewed logic a backend swap behind a stable API rather than a UI rewrite.

The scoring engine lives in src/lib/scoring.ts. Each goal is a separate function; ARS or ABI can replace any function without touching any other code.

• An overall suitability score (0-100) and qualitative band.
• Per-goal sub-scores with expandable driver / caution explanations.
• Top-N ranked biochars with weighted-points breakdown and "why this matched" reasons.
• Distance-aware producer information (nearest 5 producers visible on the map).
• Recommended amendment rate (placeholder rationale exposed).
• Cost-benefit: total cost, NRCS payment offset, net cost per acre, indicative carbon storage.
• Printable / PDF-saveable NRCS-grade report ready for CPS 336 conversations.

The Suitability Tool's data layer is the foundation for Phase 2. The same biochar record (including coordinates and price) feeds the Sourcing Module. The same SSURGO query feeds the NRCS Implementation Module. The same priority/goal model feeds the Learning Center's curriculum structure. The Deployment Database uses the same scenario shape as a write-once log of field trials.

Stack: Next.js, MapLibre GL JS, Tailwind CSS, and standard PostgreSQL-compatible storage for future supplier and trial data. Open-source throughout — no vendor lock on core functionality.

• Suitability scores and application rates produced by this prototype are not for field use.
• SSURGO returns the dominant component of a map unit at any point. Real-world landscapes contain heterogeneity; site-specific soil testing is recommended.
• Trace metal screening is essential for biosolids- or manure-derived biochars; analytical verification is the user's responsibility.
• The tool is a prototype submitted with our response to the ABI Phase 1 RFP. It is not a published ABI release and does not represent ABI policy.