PART 2 – ESSENTIAL NUTRIENTS
INTRODUCTION
The essential elements have a minimal physiological effect in themselves but are active when combined in certain organic compounds or as ions in solution. Essential nutrients have a number of vital functions in plant growth and development such as
a.Constituents of living tissues.
b.Catalysts in certain biochemical reactions.
c.Influencing the cell osmotic pressure.
d.Influencing the acidity of plant tissues.
e.Affecting membrane permeability for nutrient uptake and transport.
Carbon, hydrogen and oxygen are required for synthesis of carbohydrates, proteins, lipids, and related compounds. Since these three essential nutrients are contained in most organic compounds found in plants, they have a major function in normal plant growth and development. The remaining 13 essential nutrients will be discussed in more details since each has specific function within the plant.
NITROGEN
Turf grasses require nitrogen in the largest amount of any of the essential nutrients with the exception of carbon, hydrogen and oxygen. For this reason, nitrogen is the nutrient applied in the largest amounts in turf grass fertilization program. It is a vital constituent of:
a.The chlorophyll molecule, which is involved in photosynthesis.
b.Amino acids and proteins, which compose a major portion of the protoplasm.
c.Nucleic acids, which functions in hereditary transfer of plant characteristic.
d.Enzymes and vitamins, which catalyze metabolic reactions within the plant
Effects of Nitrogen
Nitrogen nutrition can affect a turf in a number of ways including:
a.Shoot growth
b.Roots growth
c.Shoot density
d.Color
e.Disease proneness
f.Heat, cold, and drought hardiness
g.Recuperative potential
h.Composition of the turfgrass community.
What Happens If Grass Gets Too Much Nitrogen?
Nitrogen turns your grass dark green and lush, but too much nitrogen can seriously damage your lawn. When grass gets too much nitrogen, whether through dog urine or too much synthetic fertilizer, it:
a.Burns the tips or turns grass yellow and brown
b.Lowers your lawn’s ability to withstand high or low temperatures
c.Shrivels roots, which makes it hard for them to absorb water
d.Increases the grasses’ vulnerability to disease, like leaf spot
What Are The Signs Of Too Much Nitrogen?
The main signs of too much nitrogen in the lawn include:
a.Grass with brown, “burnt” tips
b.Stripes or patches of brown, green and yellow grass
c.Straw-coloured patches
At the end stage, the grass has turned completely brown and crunchy. When you pull on it, it comes out without any resistance. The roots look “burned”, are black, or have the consistency of mush.
If you recently fertilized with synthetic fertilizers (especially quick-release), and especially if the brown grass appears in lines, then you are likely to have over-fertilized with too much nitrogen.
It is important to maintain a controlled level of nitrogen nutrition that:
a.Avoid excessive leaf growth requiring more frequent mowing.
b.Does not stimulate shoot growth to the extent that root growth is impaired.
c.Varies with the environmental and cultural conditions.
Excessive nitrogen fertilization is usually a greater problem on intensively cultured turf than a nitrogen deficiency.
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