Guide to perform an adequate fertigation
With the fertirrigation we are unifying two of the indispensable elements for the development of a plant, water and nutrients. If we perform this operation correctly, we will achieve surprising results. This process has its advantages and disadvantages that we will discuss in this article. Basically, fertigation involves introducing a specific nutrient into the irrigation water, either through a simple fertilizer or something more complex. To do this, you must have prior knowledge and make some estimation calculations to know the exact amount of fertilizer to be added. The particularity that this form of watering and fertilizing has at the same time is that it has a great application to intensive crops.
The measures are very controlled and we try to optimize the whole process to the maximum. This is done by calculating the exact amounts of minerals that the plants absorb to complete their biological cycle and contribute them to the soil. To know this information you have to consult the bibliography and several studies such as soil analysis and leaf analysis. That’s why the greatest application is for intensive crops.
Rational fertilization It is intended that, despite the fact that there are great advances in fertilizer and irrigation application equipment, classical techniques of proven usefulness should not be abandoned. With this we reduce the applications of soluble fertilizers for irrigation equipment that are not cheap compared to natural fertilizers.
This system of irrigation and fertilization 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.
- Green fertilizer.
- Take advantage of crop residues. As it is possible that these techniques do not complete all the exact needs of the crops, it can be complemented with fertigation.
RATIONAL SUBSCRIBER SCHEME We start by knowing “what we have”
1. Analysis of water quality
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 Subscriber of background (previous to the crop)
1. Reconstitute the nutritional values of the soil (knowing its values through analysis) Fertilization of cobertera (with the crop)
- It can be normal fertilization (solid fertilizers contributed manually or mechanically on the plants),
- o Fertigation
ADVANTAGES OF THE FERTIRRIGATION
- Only the moist bulb around the plant has moisture and nutrients. Great optimization of resources.
- Low-quality water can be used more profitably.
- Excess nutrients are avoided and, therefore, contamination of soil and groundwater.
- Agricultural work and maintenance are considerably reduced.
- Requires less labor and maintenance costs are saved.
- The compaction and erosion of the soil is reduced (no mechanical work will be done to supply nutrients).
- Water saving.
DISADVANTAGES OF THE FERTIRRIGATION
- Water-soluble fertilizers are quite expensive compared to traditional fertilizers.
2. The cost of the initial infrastructure to be able to add fertilizers to water.
3. Calculations are required to know the dose, the conversions and the irrigation operation.
4. The equitable distribution of fertilizer depends on the quality of the irrigation system.
5. Salinity levels in the water can increase if no action is taken.
6. You must have knowledge about the fertilizer mixture and its compatibility.
7. The drippers can be easily clogged.
CHARACTERISTICS OF USED FERTILIZERS
What is sought when producing new fertilizers for this type of irrigation is the following:
• That they have a total solubility in contact with water.
• That they have low sales content, so as not to damage the soil and the plants.
• Make it as pure as possible, to reduce the seals in the droppers.
OBTURACIONES IN THE DRIPPERS
As we have said before, this is one of the big problems in modern fertigation. There are some means (not only chemicals) to reduce the seals, such as electronic decalcifiers (the electronic impulses that are generated that alter the crystallization process of liquid calcium). However, another method that is also effective is the incorporation into fertirrigation of nitric acid.
With the application of this compound, on the one hand the sealing of the drippers is eliminated, and on the other hand, the quality of the water is improved, because it decomposes the bicarbonates it contains naturally.
Its application is weekly or monthly, to obtain an average maintenance of the entire irrigation installation. Another standardized use is to reduce the pH of a soil when it is very basic.
INJECTION OF FERTILIZERS IN THE IRRIGATION HEAD
We start from the irrigation head, electrovalves, filters, pressure gauges, programmers, counters, etc. If we want to apply fertilizers in the water, we need a fertilizer spreader or equipment, as it is technically known. The fertilizer injection, that is, the 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). In order to look at the economy, the Venturi injector is the cheapest but, therefore, the one that loses the most pressure. Hence the importance of choosing compensating drippers to avoid imbalances in irrigation, especially when the Venturi is working.
The fertilization tank has a simple installation: a container of large measures connected in parallel to the network where the fertilizer is added. Depending on the output flow (less at the end), the fertilizer concentration will vary, which is why the problems it presents when releasing the same amount of fertilizer, especially when working with different irrigation sectors and not irrigating at the same time .
The injection pump is, of the three, the most accurate, but also the most expensive. 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.