What is Subsurface Irrigation? all you need to know

Irrigation systems became more and more technical over time until they could be fully remotely controlled and achieved ever-increasing efficiency. One of the articles 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 problems that need to be controlled very precisely.

For this reason, we are going to dedicate this article to telling you what subsurface irrigation is, what are its characteristics, advantages and disadvantages.

What is Subsurface Irrigation

Subsurface irrigation is a method of applying water below the surface of the ground. To do this, depending on the type of soil, the microtubules are buried variable depths between 10 and 50 cm, and low discharge rates, 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 at high frequency. In other words, do a lot of watering with 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 way and in a reduced volume.

Agricultural challenges

One of the greatest challenges of any irrigation system is achieving as efficient as possible to save the most water and money. Most of the water lost is produced by evaporation. For overhead irrigation systems such as sprinklers and diffusers, the water sprayed into the air undergoes some evaporation (and the other part is blown away) before falling.

For drip irrigation, evaporation is reduced but still significant. Also, on steep slopes, there may be runoff damage (water running off the surface before soaking into the ground).

Underground drip irrigation systems consist of burying drip irrigation pipes at a depth between 10 and 50 cm (depending on what is watered) so that all the water is supplied underground.

Each dripper forms a wet bulb (high humidity area) that does not reach the surface. To avoid root problems, watering should be continued long enough for the moist bulbs to come together and form a moist border.

Advantages of underground irrigation

• More water savings. Reduce or prevent water loss through surface evaporation, since water does not reach the surface except in specific growing situations.
• Avoid runoffachieve greater irrigation uniformity and avoid wind problems.
• Reduces the presence of weeds by not wetting the surface of the ground
• Improves plant nutrition since water and nutrients directly reach the root system, allowing better utilization of nitrogen, phosphorus and potassium.
• Fertilizer is saved because it is more efficient.
• Reduces the presence of diseases and pests because it reduces the humidity of the stems and leaves of plants.
• Prevents rodents and birds from damaging the system.
• Save working time. Depending on the crop, side shoots should not be planted or harvested every year, as they completely prevent the degradation of thermoplastic materials caused by UV radiation.
• Accessible farming is permitted.
• Avoid the risk of sabotage.

Disadvantages

• Visual inspection is not permitted. This inconvenience can be solved with a good distribution of water meters or pressure gauges.
• Roots can get into the dripper causing clogging, and soil particles can be sucked into the dripper and clog. Currently, some lines of drippers have physical systems that prevent this from happening.
• The maintenance of buried pipes is difficult. It must therefore be installed with the utmost security.
• Installation and maintenance costs increase.

Special Subsurface Irrigation Considerations

• Anti-vacuum valve in the distribution pipe. These valves must meet two requirements: extract air from the pipeline during filling and enter air or be anti-vacuum during lateral evacuation.

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 uphill or downhill. In any case, at least one valve must be installed at the highest points of each of the distribution and washing lines.

• Side washing system
• Shorter distances between transmitters
• Check the filter if necessary.
• Emitters with special properties: they must be anti-aspirating to avoid the inhalation of particles by the dripper once the watering 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 to choose a high quality filter, which will avoid clogging problems and ensure a good uniformity of distribution of the water and fertilizers.

If you want to determine which irrigation system is best for your farm, you need to 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 as possible locally, an underground drip irrigation system is a good option and, with good management and design, will give you the best results.

lawn system

Contrary to what one might think, sub-irrigation of lawns has advantages over irrigation of trees and shrubs. To save water, you 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 them while someone is there.
• Reduce the spread of disease. Standing water in the lawn can act as a disease transmitter between some plants and others. This does not happen with subsurface irrigation.
• Destructive behaviors are avoided, which is a headache in some areas. The maintenance budget required to replace sprinklers and diffusers is not negligible. None of this is necessary for a fully buried system.
• Due to the configuration of the water delivery mechanism, sprinkler irrigation systems tend to wet unnecessary areas. With a buried irrigation system, the water is where it should be, not on the walkways, benches, utility poles, streets, etc.
• Significant survey is required in areas with steep slopes to achieve maximum uniformity in sprinkler irrigation. However, there will always be some unavoidable moisture loss. Buried irrigation systems handle non-uniformity well as long as the proper check valve is used to achieve good uniformity.

I hope with this information you can learn more about subsurface irrigation and its features.