The Role of Fertilizer

Soil is a natural body of finely divided rocks, minerals, and organic matter. Sand, silt, clay, and organic matter help provide tilth, necessary aeration and water holding capacity, but seldom maintain adequately balanced nutrients (plant food) to sustain continuous plant growth and improved yield. Thus, requiring the addition of fertilizer to maintain their fertility.

I.   Primary Plant Food Elements

Nitrogen | Phosphorus | Potassium (Potash) --- Plants utilize these nutrients in the largest amounts and unfertilized soils typically cannot provide them in quantities needed for optimal plant growth and yield.

Nitrogen (N) 1. Promotes rapid vegetative growth (leaf and stems) hastening recovery after stress. 2. A vital element in the formation and function of chlorophyll, the key ingredient imparting dark green vegetative color. 3. Synthesizes amino acids which form protein. 4. Regulates the uptake of other nutrients. 5. Basic ingredient of vital compounds – Nucleic acid and enzymes.

Phosphorus (P) 1. Stimulates early root formation and growth–gets plants off to a good start and form greater root biomass to better enable the soil area to collect the other nutrients 2. Hastens maturity (conversion of starch to sugar). 3. Stimulates blooming and seed development. 4. Required for energy transformation and conversion processes in which sugars are converted to hormones, protein and energy to grow new leaves and fruit. 5. Forms nucleic acids (DNA and RNA). 6. Vital for photosynthesis (greening for plants).

Potassium (K) 1. Aids in the development of stems and leaves. 2. Increases disease resistance and hardiness. 3. Strengthens cell wall. 4. Water intake by plant cells can be affected; plants with inadequate potassium may wilt with more than enough moisture. 5. Acts as a catalyst in Iron uptake. 6. Essential to the formation and translocation of protein, starches, sugar, and oil–improving the size and quality of fruit, grains and tubers.

II.   Secondary Plant Food Elements

Calcium | Magnesium | Sulfur They are used in less quantities than the primary elements, but in much larger quantities than micronutrients.

Calcium (Ca) 1. Calcium is an essential part of cell wall structure and must be present for the formation of new cells. 2. Deficiency of calcium causes weakened stems and premature shedding of blossoms and buds.

Magnesium (Mg) 1. Essential for photosynthesis (greening of plant). 2. Activator for many plant enzymes required in growth process.

Sulfur (S) 1. A constituent of three amino acids and is therefore essential in the formation of protein. 2. Helps maintain green color in plants. 3. Improves alkaline soils. 4. Helps compacted soils–making them loose and allowing better water penetration. Sulfur Note –There are commonly two types of sulfur applied to plants and soils: Sulfate Sulfur ≠ (SO4); Elemental Sulfur (S).

III.   Micronutrients

Iron | Zinc | Manganese Even though micronutrients are used by plants in lesser amounts, they are just as essential for plant growth as primary and secondary nutrients. They must be maintained in balance for all nutrients and water to be used efficiently.

Iron (Fe) Iron is required for the formation of chlorophyll in the plant cell (maintain a healthy green color). It serves as a catalyst for biological processes such as respiration, symbiotic fixation of nitrogen and photosynthesis. Applications of iron can correct iron deficiency, but it may be temporary in high pH soils.

Zinc (Zn) Zinc is an essential component of several plant enzymes. It is a part of auxins and controls the synthesis of indoleacetic acid which regulates growth compounds. Zinc also affects the intake and efficient use of water by plants.

Manganese (Mn) Manganese serves as an activator for enzymes in plants. Without Manganese, the plants cannot use the iron which they have absorbed. It assists the iron in chlorophyll formation which causes yellowish plants to green up.