FUNCTIONS OF ESSENTIAL

PLANT NUTRIENTS

A. PRIMARY ELEMENTS

1. NITROGEN
(N) Used in the form of nitrates (NO3) mostly. Many plants absorbed some nitrogen in the form of ammonium nitrate (NH4+) which is converted to (NH3) inside the plant.

Functions:
A. Essential in the formation of chlorophyll.
B. Essential in the formation of amino acids which makeup protein molecules.
C. Stimulates plants for rapid growth.

2. PHOSPHOROUS (P205)

Functions:
A. Necessary for cell division and multiplication.
B. Involved in energy transfer within the plant.

Comments:
Is nonmobile and relatively non-leachable in the soil. Will tie up minors in the soil if too high a concentration, Associated with the stimulating root growth.

3. POTASSIUM (K2O)

Function:
A. Required for enzyme reactions.
B. Necessary for carbohydrate metabolism.

Comments:
Second most demanded nutrient. Readily leached from the soil.
Associated with flowering and color enhancement.

B. SECONDARY ELEMENTS

1. Calcium (Ca)

Functions:
A. Associated with root tip and bud growth.
B. Increases the strength of stems and stalks, stabilizer cell membranes.

Comments:
Usually provided in liming materials. Excess calcium can cause micronutrient deficiency.

2. Magnesium (Mg)
A. Functions along with iron in the formulation of chlorophyll.
B. Enhances the activity of respiratory enzymes.
C. Essential for full activity of CO2 fixing enzyme.

3. Sulfur (S)

Functions:
A. Indirectly aids in root formation.
B. Necessary in formation of certain plant amino acids.

Comments:
Usually supplied in sufficient quantity in a granular fertilizer program. Added to the soil when it’s desirable to lower the pH.

4. Iron (Fe)

Functions:
A. Essential for chlorophyll formation.
B. A vital part of the plants oxygen carrying system.
C. Plays an essential role in nucleic acid metabolism.

Comments:
Unavailable in soils with: very high pH or very low pH; wet or compacted soils; or where soluble phosphorous is present.
Iron chelates are the best source of iron to correct iron deficiencies.

5. Manganese (Mn)

Function:
A. Enhances electron transfer from H2O to chlorophyll.
B. Acts as a catalyst in speeding up plant biochemical processes.

Comments:
Insoluble in high pH soils.

6. Zinc (Zn)

Functions:
A. Vital for the oxidation process in the plant.
B. Important for the transformation of carbohydrates.

Comments:
Contained in some fungicides.

7. Copper (Cu)

Functions:
A. Enzyme activator and important in the utilization of protein.
B. Plays an indirect role in chlorophyll production.

Comments:
Will accumulate in the soil. If toxic levels occurs, lime to pH of 6.5 to 7.0.

8. Boron (B)

Functions:
A. Associated with cellular activity that promotes maturity and increases flower set.
B. Gives proper elasticity to cell membranes.

Comments:
Very narrow range between deficient concentration and toxic concentration in the soil.

9. Molybdenum (Mo)

Functions:
A. Vital for the reduction of nitrogen to the nitrate form.
B. Necessary in the reproduction phase of plant growth.

Comments:
Required in extremely small amounts.