| name | nutrient-analysis |
| description | Interpret soil test nutrient data, identify deficiencies, query trends, and generate comparison reports. Use when asked to identify which fields need lime, find all phosphorus-deficient fields, compare nutrient values between tests, generate a before/after amendment report, or explain what a nutrient status means for crop production. Triggers include "which fields are deficient", "nutrient trend", "before after comparison", "lime recommendation", "N P K status", "improvement report", or any analytical question about soil chemistry data. |
nutrient-analysis
Query and interpret soil nutrient data from soil-test-tracker to identify deficiencies, track improvement, and guide amendment decisions.
When to Use
- Finding all fields with a specific nutrient below optimal
- Comparing nutrient values between two different test dates
- Identifying which amendment corrected a deficiency
- Explaining what a status badge (low, deficient, high) means
- Querying trend data for a specific nutrient over time
Nutrient Status Interpretation
Deficient
Value is below 50% of the optimal low threshold. Immediate action is needed before planting. Crop yields will be significantly affected.
Examples: pH below 3.0, OM below 1.5%, P below 10 ppm
Low
Value is between the deficient threshold and the optimal low. Action recommended before next growing season. Minor yield reduction likely.
Optimal
Value falls within the low-high range. No amendment needed.
High
Value exceeds the optimal high threshold. Excess may lock out other nutrients. Avoid applying more of this nutrient.
Analytical Queries
Find all deficient fields
curl http://localhost:3004/api/analytics/field-summary
Filter in the response where any nutrient has status: "deficient".
Get nutrient trend for a specific field
curl "http://localhost:3004/api/analytics/trends?field_id=..."
Compare two specific tests
curl http://localhost:3004/api/tests/{test_id_1}
curl http://localhost:3004/api/tests/{test_id_2}
Before/after amendment report
curl "http://localhost:3004/api/analytics/improvement?field_id=..."
Returns per-nutrient comparison between the test that prompted the amendment and the most recent test after it.
Nutrient Relationships
Understanding how nutrients interact helps interpret test results:
| Situation | Cause / Solution |
|---|
| Low pH locks out Phosphorus | Raise pH with lime before adding P |
| High K competes with Mg | Balance K and Mg applications |
| Low OM reduces N availability | Compost and cover crops build OM |
| High pH (alkaline) causes Fe, Mn deficiency | Lower pH with sulfur |
| Very low CEC means nutrients leach quickly | Build OM to increase CEC |
Amendment Matching
To find what amendment was applied for a specific deficiency:
curl "http://localhost:3004/api/amendments?field_id=..."
curl "http://localhost:3004/api/amendments?field_id=...&from=2024-04-01"
Radar Chart Interpretation
The Analytics radar chart shows each nutrient as a percentage of the optimal midpoint:
- 100% = exactly at the optimal midpoint
- Below 100% = below midpoint (may be low or deficient depending on distance)
- Above 100% = above midpoint (may be high depending on distance)
A "balanced" radar shows all axes close to 100% with roughly equal extension.
Troubleshooting
Improvement report shows no change
The improvement report compares the test linked to an amendment (via test_id) against the most recent test after the amendment application date. If the most recent test predates the amendment, no comparison is possible. Add a new test after the amendment was applied.
Field shows different status than expected
The status is calculated server-side against the current optimal ranges at query time. If you change optimal ranges, previous test statuses are re-evaluated on the next query.
