Irrigation systems have become more and more technical over time until they can be fully controlled remotely and achieve ever-increasing efficiency. One of the items that has aroused the most interest among farmers in recent years is the underground irrigation. It has undeniable advantages over other systems, but it also has some problems that need to be controlled very precisely.
For this reason, we are going to dedicate this article to telling you what underground irrigation is, what its characteristics, advantages and disadvantages are.
What is underground irrigation
Subsurface irrigation is a method of applying water below the surface of the soil. To do this, depending on the type of soil, the microtubules are buried variable depths between 10 and 50 cm, and discharge flows are low, between 0,5 and 8 l/h. In this way, only certain parts of the soil are moistened and the moisture does not rise to the surface. The volume of soil wetted by each tube is called the wet bulb.
This irrigation strategy involves the application of very small amounts of water and high frequency. That is, do a lot of watering in each watering, and each watering reduces the amount of water. This ensures that the moisture in the soil remains at a constant level, preventing fluctuations in soil moisture.
This method, like surface drip irrigation, has as its main objective provide continuous support to the plant and supply water and nutrients in a localized manner and in a reduced volume.
One of the biggest challenges of any irrigation system is to achieve as efficient as possible to save the most water and money. Most of the water lost is produced by evaporation. For aerial irrigation systems such as sprinklers and diffusers, the water sprayed into the air undergoes some evaporation (and the other part is carried away by the wind) before falling.
For drip irrigation, evaporation is reduced but still important. Also, on steep slopes, there may be some damage due to runoff (water flowing over the surface before seeping into the ground).
Subterranean drip irrigation systems consist of burying drip irrigation pipes to a depth of between 10 and 50 cm (depending on what is being watered) so that all the water is supplied underground.
Each dripper forms a wet bulb (area of high humidity) that does not reach the surface. To avoid root problems, watering should be continued long enough for the wet bulbs to come together and form a wet border.
Advantages of underground irrigation
- Greater water savings. Reduce or prevent the loss of water by surface evaporation, since the water does not reach the surface, except in specific cultivation situations.
- Avoid runoffachieve greater irrigation uniformity and avoid wind problems.
- Reduces the presence of weeds by not wetting the surface of the land
- Improves plant nutrition since water and nutrients reach the root system directly, thus making better use of nitrogen, phosphorus and potassium.
- Fertilizer is saved because it is more effective.
- Reduces the presence of diseases and pests as it reduces the humidity of the stems and leaves of the plants.
- Prevents rodent and bird damage to the system.
- Save work time. Depending on the crop, side shoots should not be placed or harvested annually, as they completely prevent degradation of thermoplastic materials caused by UV radiation.
- Accessible agriculture is allowed.
- Avoid the risk of sabotage.
- Visual inspection is not allowed. This inconvenience can be solved with a good distribution of water meters or manometers.
- Roots can seep into the dripper, causing clogging, and soil particles can be sucked into the dripper and clog. Currently, some ranges of drippers have physical systems that prevent this from happening.
- Buried pipe maintenance is difficult. Therefore, it must be installed with the utmost security.
- Installation and maintenance costs increase.
Special Subsurface Irrigation Considerations
- Anti-vacuum valve in distribution pipe. These valves must meet two requirements: extract air from the pipe when filling and enter air or be anti-vacuum when evacuating from the side.
The location of these valves is very important for them to achieve their goals. The location will depend on whether the terrain is sloping and whether the slope is up or down. In any case, at least one valve must be installed at the highest points of each of the distribution and washing lines.
- Side wash system
- Shorter distances between transmitters
- Check the filter if necessary.
- Issuers with special properties: they must be anti-suction to prevent the inhalation of particles through the dripper once the irrigation has stopped, and they must be very anti-clogging and self-cleaning when dirt gets inside.
In summary, the advantages of subsurface drip irrigation outweigh the disadvantages. To mitigate the latter, as you can see, it is very important to be very careful in the design of the system and choose a high-quality filter, which will prevent clogging problems and ensure good water and fertilizer distribution uniformity.
If you want to determine which irrigation system is the best for your farm, you must carry out an exhaustive study of the characteristics of the farm and its water needs, taking into account the availability of water and considering the budget to invest in the installation. If you want to conserve as much water locally as possible, a subsurface drip irrigation system is a good option and, with good management and design, will give you the best results.
Contrary to what we might think, subsurface irrigation for lawns has advantages over irrigation of trees and shrubs. To save water, we can add:
- Lawn is readily available as there are no running sprinklers. For lawns that are used frequently and continuously (such as near a swimming pool), water it while someone is on it.
- Reduce the spread of disease. Stagnant water in the lawn can act as a transmitter of diseases between some plants and others. This does not happen with buried irrigation.
- Destructive behavior is avoidedwhich is a headache in some areas. The maintenance budget required to replace sprinklers and diffusers is not small. None of this is necessary for a fully buried system.
- Due to the configuration of the water distribution mechanism, sprinkler irrigation systems tend to wet unnecessary areas. With an in-ground irrigation system, the water is where it needs to be, not on walkways, benches, utility poles, streets, etc.
- Significant investigation is required in areas with steep slopes to achieve maximum uniformity in sprinkler irrigation. However, there will always be some unavoidable moisture loss. In-ground irrigation systems cope well with non-uniformity as long as the proper check valve is used to achieve good uniformity.
I hope that with this information you can learn more about underground irrigation and its characteristics.