Fertigation is the application of fertilizers, soil amendments, or other water soluble products through an irrigation system. Chemigation, a related and sometimes interchangeable term, is the application of chemicals through an irrigation system. Chemigation is considered to be a more restrictive and controlled process due to the potential nature of the products being delivered (pesticides, herbicides, fungicides, etc.) to cause harm to humans, animals or the environment. Therefore chemigation is generally more regulated than fertigation.Fertigation is used extensively in commercial agriculture and horticulture and is starting to be used in general landscape applications as dispenser units become more reliable and easy to use.
Benefits of fertigation over traditional broadcast or drop fertilizing methods include:
* Increased nutrient absorption by plants
* Reduction in fertilizer and chemicals needed
* Reduced leaching to the water table and,
* Reduction in water usage due to the plant's resulting increased root mass being able to trap and hold water
Because of the potential risk in contaminating the potable (drinking) water supply, a backflow prevention device is required for most fertigation systems. Backflow requirements vary greatly so it is very important to understand the proper level of backflow prevention required by law. In the United States the minimum backflow protection is usually determined by state regulation but each city or town may increase the level of protection required.
Texas State law Chapter 344.73 in Subchapter D 1. (b) “An irrigation system which adds any chemical is considered to be a “high health hazard”. Such an irrigation system must not be connected to any potable water supply except through a reduced pressure principle backflow prevention assembly. "
