Plants need nutrients to grow. Depending on the conditions of the soil in which they've been planted, these sufficient nutrients are usually available. Growing plants take in these nutrients--if they're not replaced at the same rate at which they're used, a deficiency occurs. Artificial fertilizers are used to replace nutrients and promote healthy, vigorous growth in plants.
Plants require 16 nutrient elements to grow. Carbon, hydrogen and oxygen are provided by the air, while the rest are taken in from the soil. Inorganic fertilizers often provide the three major nutrients a plant's roots take in from the soil: nitrogen (N), potassium (K) and phosphorous (P). Other nutrients are needed in smaller amounts. These are called micronutrients. Many artificial fertilizers do not supply the micronutrients, only the essential macronutrients.
Inorganic fertilizers are broken down into to different release types: fast and slow. Slow-release methods provide nutrients slowly to the plants over the course of a season. As the fertilizer materials break down slowly, plants get a constant supply. Application of slow-release fertilizers is not recommended around trees and shrubs, as it keeps the plants growing too long into the season says Clemson University. Fast-release fertilizers release nutrients immediately, stimulating growth all at once. They are often used in turfgrasses to give the grass a green appearance.
Inorganic fertilizer is a major source of water pollution. Misapplied high-nitrogen fertilizer often leaches into drainage systems or runs into nearby lakes and streams. The artificial forms of nitrogen used in chemical fertilizers are water-soluble says Iowa State University, and travel easily in rain water, lakes and streams. Nitrogen that drains into bodies of water promotes the growth of algae, which may deplete the water's oxygen, causing other life in the water to die off. Nitrogen in drinking water causes blue-baby syndrome in infants 6 months and younger, since it reduces the blood's ability to process oxygen properly, according to the Benton Franklin Health District. Also at risk are pregnent women, persons with reduced gastric acidity and those who have a hereditary lack of methemoglobin reductase.