Fertigation (Chemigation)

Fertigation (also known as chemigation) is the injection of fertilizers, soil amendments, and other water-soluble products into an irrigation system. The two terms are sometimes used interchangeably. Chemigation often involves pesticides, herbicides, and fungicides, some of which pose health threat to humans, animals, and the environment.

 

Typical Methods used:

Drip Irrigation Systems

Sprinkler / Proportional Feed Systems

Continuous Application

Three-stage Application

 

Other methods of application include the lateral move, the traveler gun, and solid set systems.

 

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.

 

Commonly used nutrients:

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 biological available 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 mono-ammonium phosphate or di-ammonium phosphate to serve as biological available nutrients. A common source of potassium is potassium chloride. A soil fertility analysis is used to determine which of the more stable nutrients should be used.

 

 Fertigation assists distribution of fertilizers for farmers. The simplest type of fertigation system consists of a tank with a pump, distribution pipes, capillaries, and a dripper pen. All systems should be placed on a raised or sealed platform, not in direct contact with the earth. Each system should also be fitted with chemical spill trays. Because of the potential risk of contamination in the potable (drinking) water supply, a backflow prevention device is required for most fertigation systems. In the United States, the minimum backflow protection is usually determined by state regulation. Each city or town may set the level of protection required.

 

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