Critical values of the proportion of nutrition elements to N (= 100) in the leaves for the estimation of relative nutrient deficiency (with regard to N) for deciduous trees.
| Element | Supply | ||
|---|---|---|---|
| Optimal | Sufficient | Insufficient | |
| N | 100 | 100 | 100 |
| P | 10-14 | 5-10 | <5 |
| K | 50-100 | 25-50 | <25 |
| Mg | 10 | 5-10 | < 5 |