Fertigation – what to consider?

This is a well-known method of fertilization, and it’s getting more popular every day. Nonetheless, there are some factors regarding fertigation systems that most people still aren’t familiar with and that can be detrimental to the absorption of nutrients by the plants.


Picture by Jugurte

This fertilization method consists of an application of nutrients in hydro soluble forms, diluted in the irrigation water. Its major quality is the possibility to divide the nutrient dose throughout the whole cycle. Fertigation systems are usually sophisticated and expensive, which normally limits its use for high value crops. Before deciding if this is the best choice of fertilizer application for a crop, there are a few things that need to be considered:

  • Cost-benefit

The fertigation system’s implantation is usually somewhat expensive. However, this method provides equal or higher yields compared to traditional fertilization with lower costs on manpower, less waste and better use of fertilizers. These aspects should be taken into account in order to conclude if it is a good fertilizer application method economy wise.

  • Soil characteristics

Knowing the soil’s features is indispensable for fertigation, because every aspect of the soil will influence on the outcome of the fertilization. For example, high temperatures affect photosynthesis, whether low temperatures might lead to slower reactions, low aeration decreases ATP production and all of these processes and many more need to be working correctly in order to obtain a good plant nutrition.

  • Types of fertilizers

Choosing fertilizers to be applied through irrigation water it’s not a simple task and many aspects need to be observed, such as its solubility, compatibility with other products, purity, corrosiveness, the acidifying power of the soil and irrigation water, environmental risks and financial costs.

Not all fertilizers are compatible and able to be applied together. Combining ammonium sulfate and potassium chloride for example, will decrease the fertilizers’ solubility in the tank. Or applying calcium in a water with high concentration of bicarbonate may form a precipitate that can clog the filters.

Potassium, nitrogen and micronutrient fertilizers are usually hydro soluble, and are unlikely to cause any problems in the system. On the other hand, phosphorous fertilizers aren’t recommended for fertigation, because most of them are not water soluble, which may lead to precipitation, and they also take longer to be available for absorption once applied to the soil.

Not to worry, even though some nutrients might not be frequently recommended for fertilization through irrigation system, there are still a few options on how to use them in a way that won’t tamper with the fertigation. If calcium needs to be applied, it should be on high acidic soils and with high amount of sodium. Calcium nitrate and calcium chloride are some soluble options for the application of this nutrient. For phosphorous, in case of acid waters, there is no limitation for using DAP, and if the water is basic, MAP should be used due to its acidifying effect. Concentrated phosphoric acid might also be an alternative for fertigation.

Types of fertilizers

  • Irrigation water quality

High pH, in other words, basic irrigation water, might clog the system. When water’s pH is higher than 7.5 calcium and magnesium might accumulate in the irrigation system, leading to the obstruction of the tubes. This is the reason why 6.0 is the ideal pH for the solution, and 5.5 to 7 is a free risk range.

  • Injector type

Fertigation requires that the irrigation system has an injector, responsible for incorporating the fertilizers in the water. There are many kinds of injectors, with different costs, efficiency, energy sources, etc.

  • Crop characteristics

Different plants need different amount of water and nutrients in order to survive and have good productivity. It also varies according to environmental conditions, some are more stress tolerant, others more prejudiced by salinity and so forth. Therefore, it is necessary to understand the specific needs of every crop in each growth stage and also the weather and soil characteristics of the region it is being cultivated, so that one may be conscious of how it will respond.

  • System characteristics

The irrigation system used must meet a few parameters as well. It needs to have enough pressure to ensure the solution will be evenly distributed. The injection time needs to be sufficient to reach the roots, usually around one or two hours, considering at least half an hour with only clean water to wash the tubes. Lastly, it needs a high-quality filter to guarantee the refinement and constant cleanliness.

Once the important considerations for fertigation have been analyzed, and all the boxes have been checked, it is time for the final step: Finding the best fertigation system! The nutrients can be applied through surface, localized or sprinkler irrigation.

Keep in mind that if the goal is to achieve good yield and high-quality crops, reduce groundwater pollution, increase nutrient efficiency and effective application of microelements, fertigation is most likely a good alternative for your farm.

It seems as if there are many things to consider before starting to use fertigation, but, in case you don’t want to worry about any of these aspects, try the SMART Fertilizer Software, in which our exclusive algorithm will consider all of these topics for you and create the perfect fertilization plan for you crop. (Link to software tour).