How much to apply
Annual nutrient application rates (in kilograms per hectare) for different citrus types are presented in Tables 1, 2 and 3. The amount needed to be applied varies depending on the yield produced by the trees.
Table 1 Nutrient application rates for navel oranges based on yield.
| Navels - tonnes of fruit per hectare | ||||
|---|---|---|---|---|
| Nutrients (kg/ha) | 20 | 30 | 40 | 50 |
| Nitrogen (N) | 60 | 90 | 120 | 150 |
| Phosphorus (P) | 14 | 21 | 28 | 35 |
| Potassium (K) | 60 | 90 | 120 | 150 |
| Calcium (Ca) | 32 | 48 | 64 | 80 |
| Magnesium (Mg) | 6 | 9 | 12 | 15 |
Table 2 Nutrient application rates for mandarins based on yield.
| Mandarins - tonnes of fruit per hectare | ||||
|---|---|---|---|---|
| Nutrients (kg/ha) | 20 | 30 | 40 | 50 |
| Nitrogen (N) | 76 | 114 | 152 | 190 |
| Phosphorus (P) | 14 | 21 | 28 | 35 |
| Potassium (K) | 80 | 120 | 160 | 200 |
| Calcium (Ca) | 32 | 48 | 64 | 80 |
| Magnesium (Mg) | 6 | 9 | 12 | 15 |
Table 3 Nutrient application rates for valencias, lemons, grapefruit and tangelo based on yield.
| Valencias, lemons, grapefruit and tangelo - tonnes of fruit per hectare | ||||
|---|---|---|---|---|
| Nutrients (kg/ha) | 20 | 30 | 40 | 50 |
| Nitrogen (N) | 40 | 60 | 80 | 100 |
| Phosphorus (P) | 14 | 21 | 28 | 35 |
| Potassium (K) | 60 | 90 | 120 | 150 |
| Calcium (Ca) | 32 | 48 | 64 | 80 |
| Magnesium (Mg) | 5 | 7.5 | 10 | 12.5 |
When to apply
A summary of the timing of nutrient application as a percentage of the annual application is provided in Table 4.
Table 4 Nutrient application times as a percentage of annual application.
| Nitrogen | Phosphorus* | Potassium | Calcium | |
|---|---|---|---|---|
| Pre-bloom to Flowering | 40-50% | 100% (50%) | 30-40% | 70-80% |
| Cell Division | 25% | (50%) | 30-50% | |
| Cell Expansion | 25% | 30% | 20-30% | |
| * Figures in brackets refer specifically to phosphorous applied through fertigation | ||||