Strip comparisons between fertilized and nonfertilized areas may be a simple way to confirm the presence of a deficiency. In these comparisons, the nutrient can be applied either to the soil or on the foliage to overcome the deficiency. Soil application is best for macronutrients, where either soil or foliar applications are appropriate for micronutrients. The exception to this is for iron deficiency on calcareous soils where soil application of iron may not correct the deficiency.
Soil types most likely to suffer various nutrient deficiencies and fertilizers that can correct the problems
| Nutrient | Soils where deficiency is most likely | Fertilizers likely to correct deficiency |
|---|---|---|
| Nitrogen | Wide range of soils |
|
| Phosphorus | Wide range of soils |
|
| Potassium |
|
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| Sulfur | Sandy soils where leaching occurs |
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| Magnesium | Acid soils with low cation exchange capacities |
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| Calcium | Acid or serpentine soils |
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| Copper |
|
|
| Zinc |
|
|
| Iron |
|
|
| Calcareous high pH soils |
|
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| Boron | Acid sandy soils derived from igneous materials |
|
| Molybdenum | Acid soils with high iron | Molybdenum trioxide |
In many instances, the foliar sprays must be neutralized to prevent foliar burn. For example, additions of calcium hydroxide or sodium carbonate are used to neutralize the acidity and to decrease the risk of foliar scorch at high concentrations of manganese sulfate. It is best to add nutrients singly becuase of possible effects of one nutrient upon the uptake of another. Where multiple deficiencies occur, correction of one deficiency would be expected to change symptom expression and successive diagnosis and elimination of nutrient deficiencies may be possible.