Features of the underground irrigation system, its purpose. Advantages and disadvantages of hydrating the root zone. Maintenance of construction, the price of underground irrigation.
Underground irrigation is a method of supplying water in small portions to the root zone of the plant. The liquid moves through special pipes buried in the ground, in accordance with the water consumption of the seedling. We will talk about the device of the system and the installation of underground drip irrigation with our own hands further.
Underground irrigation system
Underground irrigation system diagram
The name of this irrigation method speaks for itself: the water comes to the plant roots not from the surface, but through buried sleeves with droppers. Underground irrigation takes into account the positive geotropism of the culture - the tendency of the root to grow downward. With traditional humidification, in which moisture comes from above, the roots tend to it and rise, which is contrary to the natural development of seedlings. Underground irrigation is intended mainly for fruit trees, grapes, shrubs and for use in greenhouses, where digging is rarely carried out. At the dachas, they practice the arrangement of underground irrigation for lawns and a vegetable garden with annual plants.
There are two options for supplying water to the roots - vertical and horizontal. In the first case, the liquid is supplied to them through an individual pipe from the surface. This option is widely used for rarely planted plants.
In the second case, the liquid moves underground through a system of pipes buried to a depth of 10-70 cm and moistens the soil near the plant roots. Water is supplied under low pressure, which can be created by a container raised above the ground or a low-power pump. Working pressure at the inlet to the system - 0, 4-4 bar.
Horizontal underground irrigation is used in such cases:
- Very small thickness of the fertile layer (10-30 cm), which does not allow the use of other irrigation options;
- The need to supply water directly to the roots;
- If the location of the pipes on the surface impairs the aesthetics of the site.
For underground irrigation, it is allowed to use domestic water and settled livestock drains. In this case, it is recommended to build a sump in which solids settle to the bottom. At the same time, charging and contamination of territories does not occur - all microbes are disinfected in the soil. But you cannot use water with suspensions, which settle in the sleeves and clog the holes.
The range of equipment for underground irrigation is quite large: there are simple designs with manual water supply and automated systems that work without human intervention.
The main elements of the underground irrigation system:
- Water source … Any large tank is suitable for small areas.
- Distribution pipeline … The section of the system between the tank and the underground part of the structure, to which the water conduits are connected.
- Feeding sleeves … The underground part of the structure, through which the liquid is supplied to the plants. There are two main types of these products - drip tubes or oozing hoses.
- Filters … Installed at the entrance to the sleeves.
- Cranes … Required for manual water supply.
- Pumps … Build up pressure to move water over long distances or to increase flow.
- Air vacuum valves … Air is released from the system when it is first filled.
It is easy to do underground watering with your own hands with automatic regulation of the water supply. To do this, you will need two types of sensors - taking into account the meteorological situation and controlling moisture consumption. The former include sensors for rain, solar activity and humidity. Sensors that regulate the flow of water control electromagnetic devices that block or free the way for flows.
Advantages and disadvantages of underground irrigation
Underground irrigation is one of the most effective options for soil moisture.
Users note the following design advantages:
- Subsoil irrigation creates an optimal air / water ratio for the root system, in which the plant efficiently absorbs minerals and synthesizes basic organic compounds. Other ways of moistening the soil can cause air to be squeezed out of the root zone for several hours or even days. This irrigation method has proven itself especially well on medium to heavy soils, where infiltration can last for several days.
- If the correct irrigation regime is observed, leaching of minerals near the root system does not occur.
- Underground watering allows you to control the growth and development of plants.
- The system saves fluid consumption by 40-50%, because it does not evaporate from the surface, does not erode or run off. For example, a tree needs only 40 liters of water once a week.
- Thanks to the balanced water regime, the yield increases up to 60%.
- Underground watering is allowed to be applied to most horticultural and horticultural crops.
- The service life of the water supply system increases many times - up to 7 years, and the underground irrigation system in the greenhouse functions without repair for up to 15 years.
- There are no tubes and other structural elements on the surface, which ensures the aesthetics of the site.
- Due to the lack of moisture in the upper layers of the soil, the number of weeds is reduced, and the risk of developing fungal and bacterial diseases is reduced. There is no need for frequent mechanical tillage, because the soil remains loose even in the absence of precipitation for a long time.
- It is allowed to use waste water for irrigation, which solves the problem of their disposal.
- The system is reliably protected from mechanical damage.
- In parallel with irrigation in the fields, you can carry out other operations. The underground arrangement of the pipes allows the use of equipment for processing even during irrigation.
- Fertilizers and herbicides are delivered to the roots of the plant and are fully absorbed, which increases the efficiency and safety of their use. Chemicals do not accumulate on the surface.
When watering by underground method, users often face a number of problems:
- Small roots tend to the holes in the sleeves and clog them. To protect drippers, use rooted conduits, but they are expensive. You can also use slotted tubes, they are better than emitter tubes. Long openings are more difficult for roots to penetrate than round ones.
- For underground irrigation, there must be pressure in the system. Tubing with integrated non-pressure drippers will not function, even if uncompensated.
- There is a danger of dirt entering the system after the pressure in the line is turned off.
- Underground animals and insects often damage the sleeves to get to the water.
- Damage or clogging of the tubes is not immediately detected, but in order to eliminate the malfunction, it is necessary to dig them out.
- From the point of view of operating conditions, underground irrigation is worse than surface irrigation. pipelines are not visible and soil moisture is difficult to control.
- The area to be treated is limited.
- To install the system, you have to carry out a large amount of earthwork, which takes a lot of time and effort.
- Only hoses designed for underground use should be used in the construction.
Underground irrigation system design
Installation of the structure is carried out in two stages. First, it is necessary to develop a system design and determine the number and range of its elements. After purchasing all the parts, you can start excavating and assembling the structure.
When developing a project for an underground irrigation system, various factors must be taken into account:
- Features of the relief … Lay the system hoses in such a way that the air-vacuum valves are located at the highest point of the site.
- Bookmark depth … Depends on the root-forming layer of the plant: 10 cm from the surface - for lawns, 30 cm from the surface - for most vegetable crops, 30-70 cm - for underground irrigation of decorative perennials and fruit crops, depending on the age and variety of the planting.
- Characteristics of system elements … They must provide adequate moisture to the area. With this method of irrigation, you can use pipes of a smaller diameter and low-power pumps than with surface irrigation.
- Hole pitch in sleeves … On loamy soils, the distance between the holes is made larger than on sandy loam. There is a dependence of the length of the pipes for underground irrigation on the pressure in the system.
With a dropper spacing of 33 cm, the recommended pressure in the underground irrigation system is shown in the table:
| Maximum pressure at the inlet to the system, bar | Pipe length with a dropper spacing of 33 cm |
| 1, 0 | 78 |
| 1, 7 | 104 |
| 2, 4 | 121 |
| 3, 1 | 126 |
| 3, 8 | 147 |
When designing a system, it is important to consider the composition of the water used for underground irrigation. The table below lists various threats that can impair the performance of a structure. It is necessary to resolve the issue of their neutralization or draw a plan for the supply of safe water from another source.
Threats to the underground irrigation system and their level of danger:
| Threats to the underground irrigation system | The quantity | Hazard level | ||
| Short | Moderate | High | ||
| pH | meq / l | <7, 0 | 7-8 | >8, 0 |
| Bicarbonates | mg / l | <2, 0 | >2, 0 | >2, 0 |
| Iron | mg / l | <0, 2 | 0, 2-1, 5 | >1, 5 |
| Manganese | mg / l | <0, 1 | 0, 1-1, 5 | >1, 5 |
| Hydrogen sulfide | mg / l | <0, 2 | 0, 2-2, 0 | >2, 0 |
| Total dissolved substances | mg / l | <500 | 500-2000 | >2000 |
| Solids | mg / l | <50 | 50-100 | >100 |
| Bacteria | quantity / ml | <10 | 10-50 | >50 |
Also, when designing an underground irrigation system, it is important to pay attention to the automation of the process. Completing the system with sensors, controllers and other equipment reduces human participation in the process and streamlines the operation of the system. Often, only an advanced water timer is installed, for example, a device from the Gardena underground irrigation system or similar devices.
