| Nutrient Level | |||
| Sampling time and nutrient | Deficient | Intermediate | Sufficient |
| Early season (pre-bulbing) |
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| Total N, % | <3 | 3-4 | >4 |
| PO4-P, ppm | <1000 | 1000-2000 | >2000 |
| Soluble K, % | <3 | 3-4 | >4 |
| Midseason (bulbing) |
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| Total N, % | <2.5 | 2.5-3 | >3 |
| PO4-P, ppm | <1000 | 1000-2000 | >2000 |
| Soluble K, % | <2.5 | 2.5-4 | >4 |
| Late season (post-bulbing) |
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| Total N, % | <2 | 2-2.5 | >2.5 |
| PO4-P, ppm | 1000 | 1000-2000 | >2000 |
| Soluble K, % | <2 | 2-3 | >3 |
Plant Part to sample is the tallest leaf blade.
Available Soil Nutrient Levels, ppm |
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| Soil Status | Phosphorus | Potassium | Zinc |
| Very deficient | 0-5 | <40 | <0.3 |
| Deficient | 5-9 | 40-80 | 0.3-0.5 |
| Intermediate | 10-15 | 80-120 | 0.5-0.8 |
| Sufficient | >15 | >120 | >0.8 |
Analytical methods:
Phosphorus - Olsen bicarbonate
Potassium - Ammonium acetate
Zinc
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Division of Agriculture and Natural Resources, University of California. All contents copyright © 2008 The Regents of the University of California. All Rights Reserved. Development funding from the University of California and USDA, CSREES. Please e-mail your comments to: vric@ucdavis.edu Last updated: 4/13/2009 | Website design by Lauri Brandeberry |
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