Plant roots are the delivery system for homemade and commercially available organic fertilizer. Organic fertilizer does not contain the excessive nitrogen that can cause environmental pollution problems. Synthetic nitrogen fertilizers do not add living organisms to the soil that create soil fertility. Good soil is alive with a community of up to 1 billion microorganisms per teaspoon, and it is these microorganisms that create soil nutrients.
Roots support the structure of a plant and they absorb water. Root hairs extend from the epidermis--the outer layer of plant cells. Root hairs absorb water and nutrients from the soil. They are delicate and easily destroyed by transplanting. Root hairs grow from the tap root and fibrous roots of plants.
Twenty nutrients have been identified as necessary for healthy root and plant growth, and of these, 17 are available in soil. Nitrogen, phosphorus and potassium are required in the largest amounts. Organic fertilizers often identify the percentage of these three nutrients in the N-P-K label. Other important macronutrients found in organic fertilizer include sulphur, calcium and magnesium.
Origin of Nutrients
The nutrients in organic fertilizers come from natural sources such as plant and animal residues and rock dust. Other ingredient sources for organic fertilizer include bat guano, feather meal, cottonseed meal, mined potassium sulphate, seaweed, fish and bone meal and alfalfa meal. Homemade organic fertilizer is called compost. It contains kitchen and yard waste, dry materials such as newspaper, leaves, water and air.
Good soil structure allows plant roots to grow easily and hold the plant in place. Soil with good structure is crumbly in texture and retains water easily. Organic fertilizer and homemade compost improve soil structure by adding organic matter. Organic matter helps soil hold individual mineral particles together in clusters. These clusters form the structure that roots hold on to.
Benefits of Organic Fertilizer
Organically fertilized soil increases the nutritional value of food, according to a 2007 study at the University of California at Davis. Organic tomatoes were shown to contain 79 percent more flavonoids than nonorganic tomatoes. Flavonoids are a part of the process that makes antioxidants, which are thought to be instrumental in cancer prevention. Soil amended with organic fertilizer increases its nutrient content each year.