01 · QUICK START
A complete measurement visit in ten steps.
- Prepare the equipment.Charge the Android phone, enable Location, inspect the USB-C cable and clean and dry the probes.
- Choose the sampling area.Use a representative location or intentionally identify a problem zone as separate from the normal field area.
- Open Field session.Enter the field name, crop or “Pre-plant / Bare soil,” and sampling depth. Add variety, stage, soil texture, rain, irrigation and notes when known.
- Connect the sensor.Attach it through USB OTG, tap Connect and wait for live values. Do not save zeros or a stale screen.
- Name the point.Use a stable naming system such as NF-P01. Select an existing point on return visits.
- Check GNSS quality.Wait for a recent fix. The release blocks a field save when reported accuracy is worse than ±30 m or the fix is older than 15 seconds.
- Insert consistently.Place all probes evenly to the recorded depth with good soil contact. Do not force the sensor into stones or use it as a lever.
- Capture five fresh packets.Keep the probe stable. The app requests and verifies a new sensor packet for each row; it no longer duplicates one final screen across five records.
- Review the record.Check field context, values, GPS, sensor mode, capture-quality label and screening notes before acting.
- Preserve and report.Use History and complete CSV export. If behavior is unexpected, save feedback and create a support bundle from More.
02 · SAMPLING PROTOCOL
Consistency matters as much as the number on screen.
A meaningful comparison requires a similar location, depth, timing and method. Soil can vary over short distances and through the profile, so a single convenient reading should not be treated as a field average.
Design the visit
- Separate areas with different soil, slope, drainage, crop history or management.
- Use a documented route or grid appropriate to the decision.
- Record normal and problem areas as different sampling populations.
- Use enough points or composite samples for the intended method.
Control the method
- Keep depth, insertion, settling time and cleaning consistent.
- Avoid fertilizer bands, field entrances, wet depressions and headlands unless those are the target.
- Record recent rainfall, irrigation and field operations.
- Clean probes between locations to reduce transfer and corrosion.
Protect quality
- Wait for a live sensor packet and stable contact.
- Confirm units, register mapping and calibration for the exact hardware.
- Compare questionable values with a trusted reference method.
- Keep Demo Sensor Mode out of field evidence.
Return responsibly
- Phone GNSS provides approximate navigation, not surveyed coordinates.
- Use a physical landmark when exact relocation matters.
- Review visit GPS accuracy in the export.
- Interpret a trend only when methods and context are comparable.
03 · APP FEATURES
What each workspace is for.
Connected and offline modes
Core sensing, GPS, saved points, history, local recommendations, offline advisor knowledge and CSV export are designed to remain local. Maps, weather services and a configured online model depend on connectivity and provider availability.
04 · UNDERSTANDING READINGS
Treat displayed channels as screening signals until validated.
Compatible multiparameter sensors may report temperature, moisture, SOC, pH, nitrogen, phosphorus, potassium and a fertility channel. A displayed value is not proof that the hardware measures that parameter accurately. Confirm protocol mapping, units, scaling, calibration and performance across relevant soils.
Changes biological activity, evaporation and crop development. Compare at a consistent depth and time of day.
Depends strongly on texture, contact, depth, crop stage, rainfall and irrigation. One point does not describe the full root zone.
Affects nutrient availability but crop targets differ. Confirm liming or acidification decisions with calibrated soil testing and buffer methods where appropriate.
Soil organic carbon changes slowly and laboratory methods matter. Use consistent reference testing before treating sensor values as absolute carbon measurements.
Availability depends on soil, season, method and crop demand. Never derive a fertilizer rate from one unvalidated point reading.
This may be a device-specific composite or conductivity-related channel. Verify the manufacturer protocol and interpretation before operational use.
NA∧YA’s rule cards are conservative screening prompts, not crop-specific prescriptions. “Good,” “low” or “high” labels are preliminary until calibrated for the exact sensor, soil and production context.
05 · AGRICULTURE FOUNDATIONS
General practices that strengthen observation and decision-making.
Soil health principles
USDA NRCS organizes soil-health management around four ideas: keep living roots, minimize disturbance, maximize soil cover and maximize biodiversity. FAO conservation agriculture likewise emphasizes minimum disturbance, permanent cover and species diversification. Apply these principles only in ways suited to local climate, crops, equipment, pests and economics.
Water and drainage
Plan irrigation with crop stage, root depth, soil water-holding behavior, weather, distribution uniformity and drainage. Test irrigation water when salinity, sodium, alkalinity or toxic ions may matter. Applying more water without adequate drainage can worsen waterlogging or move salts.
Nutrients and organic inputs
Base consequential nutrient decisions on representative calibrated tests, crop requirements, yield goals, field history, manure or legume credits and local guidance. Know compost and manure source, maturity and nutrient analysis. Protect waterways and follow food-safety and environmental requirements.
Crop establishment and scouting
Use adapted legal seed, crop-appropriate planting depth and a suitable seedbed. Walk a repeatable scouting route and record crop stage, pattern, severity, recent operations and photographs. Symptoms alone rarely prove a nutrient deficiency, disease or pest.
Integrated pest management
Correct identification and monitoring come before treatment. Combine cultural, biological, mechanical and chemical tools where appropriate. The complete pesticide label controls use, rate, timing, protective equipment, buffer requirements, re-entry and harvest intervals.
Records and on-farm learning
Record inputs, labor, weather, operations, observations, yields and measurement methods. Where feasible, use a clearly marked comparison for a new practice and evaluate agronomic results alongside cost, risk and operational fit.
06 · HYBRID ADVISOR
How the agricultural question feature works.
- Context is assembled. The current point, sensor snapshot and rule-based screening notes accompany the question.
- The app checks mode and connectivity. Online mode uses the tester-configured HTTPS endpoint only when an endpoint, model and encrypted access token are present.
- Offline intelligence is always ready. Fifty-five structured agronomy checklists are ranked using farmer intent, synonyms, field and crop context, and live screening signals.
- Fallback is automatic. If the online provider is unavailable, the offline answer is returned and marked as an online fallback.
- The complete record is saved. Question, answer, source, model/status, timestamp, point, sensor snapshot and local recommendations can be viewed and exported.
Safe use
Give the advisor the crop, location, growth stage, symptoms and recent management. Use its response to organize observations and next checks—not as proof, a chemical prescription or a guarantee. Confirm high-consequence decisions locally.
07 · CSV & RECORDS
Every accepted reading carries the evidence needed to audit it.
The daily readings CSV and complete export both include coordinates and all sensor channels. The complete export also combines advisor records so offline farmers, coordinators and developers can inspect the data on another device.
Identity & time
Record type, record ID, point, timestamp, tester ID and app version.
Coordinates & quality
Fixed latitude, fixed longitude, visit latitude, visit longitude, GPS accuracy, GPS provider, packet age and capture quality.
All readings
Temperature, moisture, SOC, pH, nitrogen, phosphorus, potassium and fertility.
Field context
Farm, field, crop, variety, growth stage, depth, texture, rainfall, irrigation, notes and sensor mode.
Recommendations
Rule recommendations, advisor question/answer linkage, source, model and status.
Cross-device workflow
Open More → Share Complete Export, choose an authorized destination and transfer the CSV. CSV is broadly readable, but the receiving device does not automatically merge it back into the app. Keep an original backup and protect coordinates and notes.
08 · FIELD TESTING
What initial testers should validate.
- USB permission and reconnection after cable removal
- Five distinct fresh packet timestamps per capture
- Reasonable repeatability in a stable test medium
- GPS recency, accuracy and point return behavior
- Offline launch, capture, history, advisor and export
- Online advisor fallback when connectivity is removed
- CSV completeness across multiple visits and points
- Readable layout in sunlight, dark mode and small screens
- Clear separation of demo and real sensor records
- Privacy notice and deliberate sharing flow
When something fails, open More → Field Test Center. Choose category and severity, describe what you expected, list the steps and save it offline. The support bundle contains diagnostics and field records but never includes the advisor access token.
09 · PRIVACY & DATA
Local-first does not mean risk-free.
Sensor records, coordinates, field names, crop context, questions, answers, feedback and diagnostics are stored in app-specific device storage. Android backup is disabled for this field-test build. Records leave the device only through an explicit share action or an online advisor request.
Online advisor use sends the question and current sensor context to the HTTPS endpoint configured on that device. Review the chosen provider’s terms before using sensitive information. Do not put secrets, personal health information or unrelated personal data in field notes or questions.
10 · TROUBLESHOOTING
Common field checks.
The sensor does not connect.
Confirm the phone supports USB host/OTG, reseat the cable, accept the Android USB permission, remove hubs where possible and test with a known-good cable. Reopen the app after physically reconnecting.
The app blocks the five-reading save.
Read the status text. Complete required field context, connect the sensor, wait for a recent GPS fix of ±30 m or better and keep the probe stable. A missing fresh packet intentionally stops the batch.
Values look impossible or do not change.
Do not use them operationally. Clean and reinsert the probe, confirm raw packets are arriving, verify the device protocol/register mapping and compare with a reference method. Include the raw packet in a support bundle.
The map is blank.
Confirm online mode, internet access, Location permission, Google Play services and a valid restricted Maps API key in local.properties. Offline sensing and CSV features should continue.
The online advisor falls back offline.
Confirm online mode, connectivity, an HTTPS chat-completions-compatible endpoint, model and current access token. The answer status records the fallback rather than hiding it.
I cannot find the records in a file browser.
Use the app’s Share Complete Export action. Android app-specific storage is intentionally less visible to other apps; explicit sharing grants temporary access to the selected file.
11 · AUTHORITATIVE STARTING POINTS
Continue learning from primary sources.
- USDA Natural Resources Conservation Service — Soil Health
- USDA NRCS — Field Book for Describing and Sampling Soils
- Food and Agriculture Organization — Conservation Agriculture Principles
- US Environmental Protection Agency — How to Read a Pesticide Product Label
Regulations, labels, recommendations and best practices differ by location and change over time. Verify current local requirements before acting.