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Secondary Nutrients
Plants require
secondary nutrients in relatively large amounts, but are less likely to
be deficient in them than primary nutrients.
Calcium (Ca)
- Provides strength to cell walls
- Promotes root formation and leaf development
- Facilitates protein synthesis
Where additional calcium is needed:
- Soils with low pH levels
- Soils derived from low-calcium parent materials
Magnesium (Mg)
- Promotes photosynthesis and phosphorus translocation in plant
- Regulates uptake of other nutrients
Where additional magnesium is needed:- Sandy soils, especially if acidic
- Soils derived from low-magnesium parent material
- Soils receiving excessive potassium fertilization
Sulfur (S)
- Facilitates seed production
- Increases oil content in oilseed crops
- Promotes nodulation in legumes
Where additional sulfur is needed: - Soils with low organic matter, especially sandy or eroded soil
- Soils with low levels of sulfate-sulfur
- Cold, wet or poorly drained soils
Micronutrients
Compared to primary and secondary nutrient requirements, relatively
small amounts of micronutrients are usually needed, even when they are
deficient in the soil. Production practices, crop type, soil
composition and other environmental factors affect micronutrient
uptake.
Boron (B)
- Helps transport vital sugars through plant membranes
- Promotes proper cell division and development
- Assists in nitrogen and phosphorus use by plants
Where additional boron is needed: - Sandy soils with low levels of organic matter that leach easily
- Soils subjected to high amounts of rainfall or drought
- Soils with high pH levels
Copper (Cu)
- Aids plant growth and enzyme activation
- Facilitates protein synthesis and chlorophyll formation
- Promotes seed production
Where additional copper is needed:- High-organic-matter soils, such as peat or muck, or very low-organic-matter soils
- Cool, wet soils
- Acidic, sandy soils
Iron (Fe)
- Promotes chlorophyll production and photosynthesis
- Helps enzyme system with plant respiration
- Assists in protein synthesis
Where additional iron is needed: - Soils with high pH and/or high phosphorus levels
- Fields where lime has been applied within the last two to four years
- Sandy or mucky soils
Manganese (Mn)
- Promotes chlorophyll production and plant photosynthesis
- Activates enzyme systems
- Contributes to nitrate assimilation
Where additional manganese is needed: - Soils with high pH and/or high phosphorus levels
- Fields where lime has been applied within the last two to four years
- Sandy or mucky soils
Molybdenum (Mo)
- Fixes nitrogen from air in legume nodules
- Facilitates nitrate reduction to amino nitrogen for protein synthesis
Where additional molybdenum is needed: - Soils with low pH levels
- Sandy, highly weathered soils
Zinc (Zn)
- Assists protein synthesis
- Promotes seed/grain formation and plant maturity
- Aids growth regulation and enzyme systems
Where additional zinc is needed: - Soils with high pH and/or high phosphorus levels
- Crops grown in low organic matter, especially sandy or eroded soils
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