North Country Organics
Calculate Phosphorus Application
IMPORTANT NOTE: The application rate that this form suggests is for correcting an imbalance only and does not include fertilization for crop removal. Please refer to our Application Guide which provides fertility programs for various crops.
1. Find the method that was used to determine your phosphorus (or phosphate) level.
2. Determine the status (e.g., VL, M, etc.) or use the status given on the lab report.
Typically, soil test reports express phosphorus (P) in parts per million (ppm). Sometimes P levels are reported in pounds per acre (ppa).
To convert ppa P or ppa P2O5 to ppm P, Click here
NOTE: Status values are in part per million (ppm)
| Status | Bray 1 | Bray 2 | Olsen P | Mehlich 1 | Mehlich III | Morgan P |
|---|---|---|---|---|---|---|
| Very low | 0 – 8 | 0 – 11 | 0 – 3 | 0 – 5 | 0 – 13 | 0 – 3 |
| Low | 9 – 17 | 12 – 25 | 4 – 7 | 6 – 15 | 14 – 30 | 4 – 8 |
| Medium | 18 – 26 | 26 – 42 | 8 – 13 | 16 – 30 | 31 – 50 | 9 – 20 |
| High | 27 – 39 | 43 – 59 | 14 – 22 | 31 – 50 | 51 – 100 | 21 – 41 |
| Very high | 40+ | 60+ | 23+ | 51+ | 101+ | 42+ |
3. Use the form below to determine how much phosphate (P2O5) is needed (use the Average for mixed crops).
To convert ppm P to ppa P, multiply by 2.3
Enter a value of 92 for Very Low, 70 for Low, and 40 for Medium. No correction is needed with Optimum, High, or Very High soil test results.