10. Classification of soil analysis results into indices: The Olsen extractable phosphorus concentration in soil is classified into an index according to the following scale.N.I.
| Soil phosphorus index | Olsen extractable phosphorus (P) (mg P/l) |
|---|---|
| 0 | 0 – 9 |
| 1 | 10 – 15 |
| 2- | 16 – 20 |
| 2+ | 21 – 25 |
| 3 | 26 – 45 |
| 4 | 46 – 70 |