|
| P loss rating (value) | ||||
| Site characteristic (Weighing factor) | Negligible (0) | Low (1) | Medium (2) | High (4) | Very high (8) |
| Soil erosion, tons acre−1 (1.5) | None | <5 | 5 to 10 | 10 to 15 | >15 |
| Irrigation erosion (1.5) | None | Infrequent irrigation on well-drained soils | Moderate irrigation on soils with slopes of 2% to 5% | Frequent irrigation on soils with slopes of 2% to 5% | Frequent irrigation on soil with slopes > 5% |
| Runoff class (0.5) | None | Very low or Low | Medium | Optimum | Excessive |
| Soil P test (1.0) | None | Low | Medium | Optimum | Excessive |
| P fertilizer application rate, lb P acre−1 (0.75) | None | <15 | 16 - 40 | 41 to 65 | >65 |
| P fertilizer application method (0.5) | None | Placed with planter deeper than 2 inches | Incorporated immediately before crop | Incorporated > 3 months before crop or surface applied < 3 months before crop | Surface applied to pasture or applied > 3 months before crop |
| Organic P source application rate, lb P acre−1 (1.0) | None | <15 | 16 to 40 | 41 to 65 | >65 |
| Organic P source application method (0.5) | None | Injected deeper than 2 inches | Incorporated immediately < 3 before planting | Incorporated > 3 months before crop or surface applied months before crop | Surface applied to pasture or applied > 3 months before crop |