UNDERSTANDING FERTILIZER

The ideal fertilizer should be designed to completely fulfill the nutritional requirements of the plant it serves.

The three major components of a typical fertilizer are Nitrogen, Phosphorus, and Potassium; often referred to by their chemical symbols "N", "P", and "K". Thus a fertilizer with a guaranteed analysis of 25-3-5 would consist of 25% Nitrogen (N), 3% Phosphorus (P2O5), and 5% Potassium(K2O).

Mineral nutrients are classified as major, secondary, and minor elements. No one essential nutrient is of greater importance than any other. All of the essential elements are necessary for proper development of turfgrass, but the major and secondary elements are needed in larger quantities than the minor elements.

Major Elements:
Nitrogen, Phosphorus, and Potassium

Nitrogen is an essential part of all living matter. It is the basis for amino acids, which combine to form proteins. Nitrogen is associated with above ground vegetation growth and density of turf, as well as its deep green color. Deficiency is noticed in turf that has turned light green or yellow. The blades start dying at the tip and progress along the midrib until the entire leaf is dead.

Phosphorus is the key nutrient in seeding development since it contributes so much to initial root development and seed formation. It is directly related to the vital growth process. Deficiency is most likely to be observed in seedling growth when new seedlings are slow to develop. On established grasses the leaves tend to turn purple.

Potassium otherwise known as potash is found in large quantities in the plant. Potassium is associated with winter hardiness and disease resistance in turf. Deficiency will appear in the blades becoming streaked with yellow, turn brown at the tips and eventually die. Susceptibility to disease and winter injury is also increased.

Secondary Elements: Sulfur, Calcium, and Magnesium
A soil may be alkaline, acidic or essentially neutral. The alkalinity or acidity of a soil is measured by its pH.

All pH values occur somewhere in a scale running from 0 to 14. A pH of 7 is neutral with numbers less than 7 indicating acidity and numbers over 7 being alkaline. It is commonly accepted that a pH range of 6.5 to 7 is good for raising turfgrasses. This is because overall nutrient availability is at its maximum in this range. Any time the pH strays too far from this range the nutrients become less available and more difficult for the plant to utilize.

It is possible to improve soil pH by adding high-calcium lime to acidic soils or by adding sulfur, in various forms, to alkaline soils. It is wise to have a soil test run to determine if the pH needs to be raised, lowered, or left as is.

Sulfur is an essential part of certain amino acids and proteins. Together with nitrogen this element makes new protoplasm, which enables plant cell growth. Deficiency is similar to that of nitrogen in that the leaves will turn light green or yellow, and then turn brown and eventually die.

Minor Elements:
Iron, Manganese, Copper, Boron, Chlorine, Molybdenum, and Zinc

Iron plays an integral part in chlorophyll production and is also a part of many enzymes. It is responsible for giving turf its deep green color. Deficiency symptoms include chlorotic or even white young leaves due to a reduction or loss of chlorophyll.

Other Minors are essential but not discussed here since most soils have the minor elements in the necessary amounts. A complete soil test will determine if any of these minor elements are needed.