Guide for proper fertigation

With fertigation we are unifying two of the essential elements for the development of a plant, water and nutrients. If we do this correctly, we will achieve surprising results. Of course, it has its advantages and disadvantages that, of course, we are going to comment on. We will try to create a basic guide to start with this new technique of fertilizing and watering at the same time. Let’s go to trouble!

Basically, fertigation consists of being able to introduce a specific nutrient into the irrigation water, either by means of a simple fertilizer spreader or something much more complex. To do this, you must have prior knowledge and perform some estimating calculations to know the exact amounts of fertilizer to be added. We do not want to fall short or overshoot (this would be worse).


The peculiarity of this way of watering and fertilizing at the same time is that it has great application to intensive crops . The measures are very controlled and an attempt is made to optimize the entire process as much as possible.

Source: Floramu

This is done by calculating the exact amounts of minerals that plants absorb to complete their biological cycle (grow, flower, bear fruit, etc.) and contribute them to the soil. Not one more milligram, not one less. To know this, you have to pull from the bibliography and various studies such as soil analysis and foliar analysis. That is why we say that the largest application is for intensive crops.

However, everyone can have a spreader in the automated irrigation equipment.


It is intended that, although there are great advances in fertilizer and irrigation application equipment, classic techniques of proven utility should not be abandoned . With this we reduce the applications of soluble fertilizers by irrigation equipment that, honestly, are not cheap compared to natural fertilizers.

Said irrigation and fertilizer system does not obstruct the ability to take advantage of natural (and classical) means of reconstituting the minerals lost in the soil. For example:

  • Biological nitrogen fixation.
  • Contributions of organic matter of vegetable or animal origin.
  • Padded.
  • Green manures .
  • Take advantage of crop residues.

As these techniques may not meet all the exact needs of the crops, it can be supplemented with fertigation.

Fertigation + complementary techniques = saving money = happy producer 🙂


We begin by knowing “what we have”

  1. Water quality analysis
  2. Analysis of the soil or substrate where we are going to grow

We select the ideal crop

  • Varieties adapted to our climate
  • Patterns and rootstocks
  • Selected seeds

Background fertilizer (prior to cultivation)

  1. Reconstitute the nutritional values ​​of the soil (knowing its values ​​through the analysis

Covert fertilization (with the crop)

  • It can be normal fertilization (solid fertilizers provided manually or mechanically on the plants), or fertigation.
  • According to bibliography or foliar analysis, the mineral values ​​”consumed” by the plant are restored.


  1. Only the wet bulb around the plant has moisture and nutrients. Great optimization of resources.
  2. Low-quality waters can be used with greater benefit .
  3. Excess nutrients and, therefore, contamination of soil and groundwater is avoided.
  4. Agricultural work and maintenance are greatly reduced.
  5. It requires less labor and maintenance costs are saved.
  6. Soil compaction and erosion are reduced (mechanical nutrient supply work will not be performed)
  7. Saving water.


  1. Water soluble fertilizers are quite expensive compared to traditional ones.
  2. The cost of the initial infrastructure to be able to add fertilizers to the water.
  3. Calculations are required to know the rate, conversions and irrigation operation.
  4. The equitable distribution of fertilizer depends on the quality of the irrigation system.
  5. Salinity levels in water can increase if action is not taken.
  6. You must have knowledge about the fertilizer mix and its compatibility.
  7. The droppers can be easily clogged.


Source: aefa-agronutrientes

What is sought when producing new appropriate fertilizers for this type of irrigation is the following:

  • That they have total solubility in contact with water.
  • That they have low salt content, so as not to harm the soil and plants.
  • Make it as pure as possible, to reduce blockages in the drippers.


It usually has a high percentage of nitrogen (it depends on the composition, between 33.5% and 34.5%). Said nitrogen content has a double duality. On the one hand, the nitric form is quickly absorbed by plants and is not retained in the soil, and on the other hand, the ammonia form is slow release and is retained by the soil.

It is suitable for basic soils as it produces a slight drop in pH. You already know how to know the pH of a soil.


A binary fertilizer rich in nitrogen and phosphorus (P 2 O 5). It is usually applied at the beginning and at the end of the crop, when phosphorus needs are most important.

Phosphorus, having a lower mobility than nitrogen, cannot be provided just when the needs of this mineral are required, if not a little earlier. That is, you have to anticipate.


As the composition says, it is rich in nitrogen and calcium. As you know, calcium is a very important mineral in crops, and many species, such as citrus, vegetables and fruits (pepper, tomato, strawberry, etc.) tend to have deficiencies in this component. Calcium nitrate prevents and at the same time corrects these deficiencies. This mixture is suitable for basic soils as it reduces the pH.


This fertilizer suitable for fertigation comes in handy when you need an extra supply of magnesium (MgO). Generally poor soils, with a high content of sand and little fertility (low OM level) usually present magnesium deficiencies, so it is intervened with magnesium nitrate.

Eye. Magnesium nitrate is incompatible with phosphorous fertilizers, as they present incompatibility.


As we have discussed before, this is one of the great problems in modern fertigation. There are some means (not only chemical) to reduce these blockages, such as electronic softeners (the electronic impulses that it generates causes the crystallization process of liquid calcium to be altered).

However, another method that is also effective (although less) is the incorporation of nitric acid into the fertigation .

With the application of this compound, on the one hand the clogging of the droppers is eliminated , and on the other, the quality of the water is improved, since it decomposes the bicarbonates it contains naturally. Its application is weekly or monthly, to achieve an average maintenance of the entire irrigation installation.

Another standardized use is to reduce the pH of a soil when it is very basic.

 There are many more. They are capable of correcting all or almost all the deficiencies that can occur in a crop and most can be adapted according to the needs. On the one hand, a rapid nitrogen release can be carried out (for unforeseen deficiencies or to stimulate the development of the crop), and on the other, a slow release , which occurs throughout the entire production.


We start from the irrigation head, where we have sometimes commented on its parts . Solenoid valves, filters, pressure gauges, programmers, meters, etc. If we want to apply fertilizers to the water, we need a fertilizer spreader or injection equipment , as it is technically known.

The injection of fertilizers, that is to say, fertigation, is carried out in the irrigation head. It can be done in several ways:

  • By Venturi effect .
  • Through a fertilization tank.
  • Through an injection pump (electric or hydraulic).

Looking at the economy (now more than ever), the Venturi injector is the cheapest but, therefore, the one that produces the most losses (more than 30% of the pressure is sucked). Hence the importance of choosing compensating drippers to avoid irrigation imbalances, especially when the Venturi is working.

The fertilization tank has a simple installation: a large container connected in parallel to the network where the fertilizer is added. Depending on the output flow (lower at the end), the concentration of fertilizer will vary, which is why the problems it presents when releasing the same amount of fertilizer, especially when different irrigation sectors are worked and not irrigated at the same time .

The injection pump  is, of the three, the most accurate . Sure, that means spending more rooms (of course). The flow of injected water is regulated, so the concentration is always the same. It can work electrically or hydraulically, although in the latter case it will depend on the pressure that fluctuations in concentration do not occur.

Puff! There are many things that we can tell more about fertigation, but hey, we’ll be taking them out little by little. It’s not about being heavy, is it? 🙂

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