Minerals and plants
by Herman Mylemans
Nitrogen N |
Phosphate P2O5 |
Potash K2O |
Sulphur S |
Calcium Ca |
Magnesium Mg |
Boron B |
Copper Cu |
Iron Fe |
Manganese Mn |
Zinc Zn |
Macronutrients
- (N)-Nitrogen: Part of proteins,
hormones, chlorophyll, vitamins and enzymes. Promotes stem and leaf growth.
Too much can delay fruiting.
Deficiency: reduced yields, yellowing of leaves, stunted growth
- (P)-Phosphorus: Seed germination,
photosynthesis, protein formation, overall growth and metabolism, flower and
fruit formation.
Deficiency: purple stems and leaves, retarded growth and maturity; poor flowering and fruiting. Apply close to roots. Large amounts without zinc cause zinc deficiency. Low pH <4 ties-up phosphates in organic soils.
- (K)-Potassium: Formation
of sugars, carbohydrates, proteins, cell division. Adjusts water balance;
improves stem rigidity, cold hardiness; enhances flavor, color and oil content
of fruits; important for leafy crops.
Deficiency: spotted, curled, or burned look to leaves; lowers yields.
- (S)-Sulfur: Part of amino
acids, proteins, vitamins, enzymes. Essiential for chlorophyll. Imparts flavor
to many vegetables.
Deficiency: light green leave.
Leached by watering. Water supplies may contain Sulfur.
- (Mg)-Magnesium: Critical part of
chlorophyll; functioning of enzymes for carbohydrates; sugars and fats; fruit
and nut formation; germination of seeds. It helps
regulate uptake of other elements.
Deficiency: yellowing between veins of older leaves; chlorosis; leaves droop.
Leached by watering. Foliar spray to correct deficiencies.
- (Ca)-Calcium: To raise pH. Promotes
root hair formation. Activates enzymes; structural part of cell walls; influences
water movement; cell growth and division. Required for uptake of nitrogen
and other minerals. Leached by watering. Immobile - requires a constant supply
for growth.
Deficiency: stunting of new growth in stems, flowers, roots; black spots on leaves and fruit; yellow leaf margins.
Micronutrients
- (Fe)-Iron:
Enzyme functions; catalyst for synthsis of chlorophyll;
essential for net growth.
Deficiency: pale leaves; yellowing of leaves and veins.
Leached by water and held in lower parts of soil. High pH soils may have iron present but unavailable to plants.
- (Mn)-Manganese:
Enzyme activity for photosynthesis, respiration, and
nitrogen metabolism.
Deficiency : young leaves pale with green veins similar to iron deficiency; advanced stages are white, leaves are shed. Brown, black, or gray spots appear next to veins. Plants in neutral or alkaline soils often show deficiency. Acid soils may increase uptake causing toxicity.
- (B)-Boron:
Affects at least 16 functions: flowering, pollination,
fruiting, cell division, water relationships, movement of hormones,
cell wall formation, membrane integrity, calcium uptake, movement of
sugars. Immobile, easily leached.
Deficiency: terminal bud dies, causing rosette of thick, curled, brittle leaves or brown, discolored, cracked, fruits, tubers and roots.
- (Zn)-Zinc:
Functional part of enzymes including auxins (growth hormones), carbohydrate
metabolism, protein synthesis, stem growth.
Deficiency: mottled leaves, irregular yellow areas. Zinc deficiency leads to iron deficiency. Occurs on eroded soils; least available at pH of 5.5 - 7.0. Lower pH can cause availability to the point of toxicity.
- (Cu)-Copper:
Found in roots; necessary for nitrogen metabolism; component of enzymes
may be part of enzyme systems that use carbohydrates and proteins. Deficiency:
die back of shoot tips; terminal leaves develop brown spots. Bound tightly
in organic matter. May be deficient in highly organic soils. Not readily
lost from soil but may be unavailable. Too much can cause toxicity.
- (Mo)-
Molybdenum: Needed
for nitrogen fixation and nitrogen use in the plant, specifically it
is needed to make amino acids; it stimulates plant growth and vigor
very much like nitrogen.
Deficiency: pale leaves with rolled, cupped margins. Seeds may not form; nitrogen deficiency may occur if plants are lacking Mo.
- (CI)-Chlorine:
Involved in osmosis (movement of water or solutes in
cells), ionic balance necessary to take up mineral elements and photosynthesis.
Deficiency: wilting, stubby roots, yellowing, bronzing. Scents in some plants may be decreased.
Leached by watering.
- (Co)-Cobalt:
Required by nitrogen fixing bacteria. Improves
growth, water movement and photosynthesis.
Deficiency: may result in nitrogen deficiency symptoms.
- (Ni)-Nickel:
Recently recognized as an essential element. Required
for the urease enzyme to break down urea into usable nitrogen and for
iron absorption. Seeds need nickel to germinate.
- (Na)-Sodium:
Involved in osmotic (water movement) and ionic balance
in plants.
- (Si)-Silicon:
Component of cell walls; creates mechanical harrier
to piercing - sucking insects and fungi. Foliar sprays reduce populations
of aphids on some plants. Enhances leaf presentation; improves heat
and drought tolerance, and reduces transpiration.
Deficiency: wilting, poor fruit and flower set, increased susceptibility to insects and disease.