The process of injecting fertilizer into a drip irrigation system is not new. Years of performance show that this can be extremely efficient and very effective. Often referred to as “Fertigation”, fertilizer is injected into the water supply that is regulated by one of a wide variety of injection systems.
It is important to test any chemical or fertilizer blend for emitter clogging before introducing it to the system. One way to do this is the “Jar Test”. A “jar test” is done by adding the chemical or fertilizer into a jar of the system water, and watching for any precipitate or milkiness which may occur over the next 24 hours. If cloudiness does occur, there is a chance that injection of that chemical or fertilizer blend will cause emitter clogging. It is also important to use system water in this test, because the chemicals added may react differently with water of various qualities.
When selecting an injection system for drip, it is imperative that the required flow rates for the system meet the application rates. For example, if the application rate of a zone is 4 GPM you will have to select a unit that can operate at that flow with acceptable distribution uniformity. Check with the manufacturer when operating conditions are extreme.
There are a number of manufactures making injection systems today with different approaches to the same goal: distribution uniformity. In an injection system that works with the initiation of a cycle the distribution uniformity will be that of the water itself. In a well designed and maintained drip system this uniformity of fertilizer can be much better than that attained by conventional methods of applying fertilizer. It is also important that a back flow prevented is used to keep chemicals from entering the water supply.
Fertigation is a great way to establish and sustain today’s modern landscapes. When using a fertilizer injector0 check with the manufacturer, they most likely have a blend that works best with the injector while meeting the requirements of the plant material.