Fertigation is the of fertilizers, soil amendments, and other water-soluble products into an irrigation system.
Fertigation is related to chemigation, the injection of chemicals into an irrigation system. The two terms are sometimes used interchangeably however chemigation is generally a more controlled and regulated process due to the nature of the chemicals used. Chemigation often involves pesticides, herbicides, and fungicides, some of which pose health threat to humans, animals, and the environment.
Fertigation is practiced extensively in commercial agriculture and horticulture. Fertigation is also increasingly being used for landscaping as dispenser units become more reliable and easier to use. Fertigation is used to add additional nutrients or to correct nutrient deficiencies detected in plant tissue analysis. It is usually practiced on high-value crops such as vegetables, turf, fruit trees, and ornamentals.
Most plant nutrients can be applied through irrigation systems. Nitrogen is the most commonly used plant nutrient. Naturally occurring nitrogen (N2) is a diatomic molecule which makes up approximately 80% of the earth’s atmosphere. Most plants cannot directly consume diatomic nitrogen, therefore nitrogen must be contained as a component of other chemical substances which plants can consume. Commonly, anhydrous ammonia, ammonium nitrate, and urea are used as bioavailable sources of nitrogen. Other nutrients needed by plants include phosphorus and potassium. Like nitrogen, plants require these substances to live but they must be contained in other chemical substances such as monoammonium phosphate or diammonium phosphate to serve as bioavailable nutrients. A common source of potassium is muriate of potash which is chemically potassium chloride. A soil fertility analysis is used to determine which of the more stable nutrients should be used.