Fertigation and Testing Fertilizers for Compatibility
Fertigation (applying fertilizer through your irrigation system) is an awesome option that is more efficient than traditional practices in applying fertilizer. It uses less fertilizer and the nutrients are delivered directly into the root zone. Sounds great, right? It is, until you try to put the wrong type of fertilizer through your irrigation system and it plugs up all the emitters in drip tape or the nozzles in a center pivot.
Any fertilizer that is to be run through a drip system should be put through a jar test first. If you don’t know what that is, see the video above. Basically, take your water that you are using for irrigating, put some in a jar and add a small amount of fertilizer. If there is a high concentration of bicarbonates in the water, it will become cloudy. This is a result of the bicarbonates reacting to the nutrients in that fertilizer. This can cause the emitters to plug, plus your plant won’t be able to access the nutrients that are delivered to the root zone, as they are bound by the bicarbonates. A few fertilizers we are testing and currently recommending:
Solubor is a low-cost source of boron that's easily dissolved in water. It comes dry and you solubilize it in water. It's labeled organic, so organic producers can use it. It is very plant available, low cost, easy to solubilize, and easy to inject in a drip system. All growers should be monitoring their tissue levels for boron as it can be a limiting factor, especially in high yields. Growers putting out extra nitrogen or sulfur and not addressing boron along with it, may be wasting the nitrogen and sulfur.
Dry soluble fertilizer from ICL Fertilizers. ICL is based in Israel, and the products that we have are high in phosphorus and/or potassium and are very water soluble. Most of them are acid based, meaning they will lower the pH of the water and remove bicarbonate. It is a multi-use product. It not only provides fertility to the plant, but also amends the water and could potentially amend the soil. It is a product that has been used frequently in specialty crops, and is not being stocked by large retailers. We currently have some in stock and are planning to do some testing and validate the results. If you are in need of phosphorus or potassium for in-season nutrition through your drip system, let us know.
A few other notes: common polyphosphate fertilizer, such as a 10-34-0 does NOT work for a drip system or center pivot. This is one that will plug up those emitters or nozzles. In the video below, we mix it with tap water that contains around 300 ppm bicarbonates. It becomes cloudy almost immediately.
We compared this to a phosphoric acid-based fertilizer from ICL. We mixed it with the same water and it remained clear. This is a good indication that it would run through a drip system without issues.
Orthophosphate fertilizers, such as a 9-18-8, 3-18-18, or 7-24-6 are often compatible with irrigation. Be sure to complete a jar test before injecting to ensure it remains clear.
If you have questions, please reach out to us here at NutraDrip, and we will do all we can to answer your questions.