FERTILIZING

PART 4 – ESSENTIAL NUTRIENTS

CALCIUM

Calcium is a micronutrient found in relatively large quantities in turf grass tissues, ranking third after nitrogen and potassium. Calcium functions as a

a.Vital constituent of cell walls
b.Specific nutrient requirement for meristem growth by cell division
c.Neutralizing factor for potentially toxic substance within the cell

The influence of calcium on meristematic activity is indicated by the suppression of mitotic division when a calcium deficiency occurs. Non limiting calcium levels enhance root growth, particularly root hair development. Calcium ions also exert strong influence on the absorption of other ions by the turf grass plant.

Soil Relationship

Calcium is more widely recognized for its effects on soil chemical and physical properties that influence turf grass growth than as an essential micronutrient. Calcium is normally absorbed by the plant as Ca⁺⁺. Calcium level also influences the cation exchange capacity of clay minerals formed in certain soils.

MAGNESIUM

Magnesium is a micronutrient that functions in several vital physiological processes within the plant such as

a.Being a constituent of chlorophyll
b.The translocation of phosphorus
c.Cofactors of many plant enzyme systems

Magnesium is essential for the maintenance of green color and growth in turf grasses because it is a vital constituent of the chlorophyll molecule. A high magnesium concentration can be toxic to the turf grass plant. This condition is more likely to occur on sodic soils.

Soil Relationship

Magnesium is normally absorbed by the plant as an Mg⁺⁺ ion. The magnesium content is usually higher in fine textured than coarse textured soils.

SULFUR

The roll of sulfur is primly as a constituent of certain essential amino acids such as cystine, cysteine, and methionine, which are required for protein synthesis. It is also a constituent of certain other important organic compounds in plants such as thiamine and biotin. A sulfur deficiency disrupts protein synthesis and impairs growth. Sulfur occurs in plants primarily in a form of protein, sulfates and certain volatile compounds.

Soil Relationship

Sulfur is taken up by turf grass roots primarily in the SO^— ion, although some is absorbed by the leaves as gaseous sulfur dioxide.

MICRONUTRIENT

The micronutrients iron, manganese, zinc, copper, molybdenum, boron and chlorine are just important as the macronutrients but are required by the plant in much smaller amounts. Most soils have adequate supplies of this micronutrients since the plant requirements are relatively small. However, certain organic soils and intensely leached, sandy soils may be deficient in one or more of the micronutrients.

Media Department; The RS Group.