Soil and Leaf-Tissue Test Interpreter
Paste in your lab numbers. Get a verdict per parameter, the constraints ranked by priority, and what to do about each.
The fertiliser calculator turns rates into product quantities. This one goes a step back: it reads the analysis and tells you which parameters need correcting before you buy anything.
Soil & tissue test interpreter
Leave a field blank to skip it. Bands follow the sufficiency ranges in the nutrition reference.
Bands differ by method — use the one your lab used
Soil analysis
Leaf tissue analysis — optional, most recently fully opened leaf at flowering
How the verdicts are reached#
Each parameter is placed in one of six zones against the sufficiency bands below. Anything outside the green band becomes a constraint, and the constraints are then ranked.
| Parameter | Unit | Deficient / critical | Low | Sufficient | High |
|---|---|---|---|---|---|
| pH (water) | — | < 5.3 | 5.3–5.8 | 6.0–7.0 | > 7.8 |
| Organic matter | % | < 1.5 | 1.5–2.5 | 2.5–4.0 | > 5.0 |
| P (Olsen) | mg/kg | < 10 | 10–20 | 20–40 | > 60 |
| P (Bray) | mg/kg | < 7 | 7–15 | 15–30 | > 50 |
| Exchangeable K | cmol/kg | < 0.2 | 0.2–0.4 | 0.4–0.8 | > 1.2 |
| Exchangeable Ca | cmol/kg | < 2 | 2–5 | 5–12 | > 18 |
| Exchangeable Mg | cmol/kg | < 0.5 | 0.5–1.0 | 1.0–3.0 | > 4.5 |
| CEC | cmol/kg | < 8 | 8–12 | 12–30 | > 40 |
| Zinc (DTPA) | mg/kg | < 0.5 | 0.5–1.0 | 1.0–3.0 | > 5 |
| Boron (hot water) | mg/kg | < 0.2 | 0.2–0.4 | 0.4–1.0 | > 2 |
| Salinity (ECe) | dS/m | — | — | < 1.5 | > 3.0 |
Tissue sufficiency bands are listed in Nutrition.
Corrections the interpreter applies#
- pH below 5.5 → a lime rate band is suggested, with a warning that the real rate needs a buffer-pH lime requirement test. Field estimates: 5.3–5.8 → 0.5–1.0 t/ha; 5.0–5.3 → 1–2 t/ha; below 5.0 → 2–4 t/ha cumulatively over 2–3 years.
- High K → warns that excess potassium antagonises magnesium and calcium, and checks your Mg value.
- High P → warns that excess phosphorus induces zinc deficiency, and checks your Zn value.
- pH above 7.2 → flags likely Fe, Zn and B lock-up even where the totals look adequate.
- CEC below 12 → advises smaller, more frequent fertiliser applications because the soil cannot hold a single large dose.
- ECe above 1.5 → flags salinity management (leaching fraction, water quality, mulch).
Next steps#
- Turn the corrections into a purchase list: Fertiliser calculator.
- Read the full sufficiency tables: Nutrition reference.
- Fix pH before anything else: Soil and land preparation.