- Drip irrigation history
- How the drip irrigation system works
- Drip irrigation system – design
- Selection of elements of drip irrigation system
- Drip line installation
- DIY drip irrigation
- Drip irrigation – advantages and disadvantages
- How to operate a drip irrigation system
In this Article: Drip Irrigation – History; drip irrigation system device; description and average price of system elements; how to design drip irrigation; how to choose droppers and drip tapes; installation procedure; construction of drip irrigation from scrap materials; drip irrigation characteristics; drip irrigation system operation.
In recent years, the problem of irrigating garden beds has become especially acute – the unusually high activity of the Sun and the lack of water for irrigation in natural reservoirs violate the plans of summer residents. Classic sprinkling of landscapes becomes too costly: water costs grow, along with them, absolutely unnecessary weeds grow. Meanwhile, the solution to the problem of irrigation has existed for a long time – the drip irrigation technology was developed and tested about 70 years ago …
Drip irrigation history
The effectiveness of this method of irrigation was discovered quite by accident – in 1955, the Israeli hydraulic engineer Simha Blass walked past a green hedge and noticed that one bush was more developed and taller than all the others. There were no apparent reasons for this – daily irrigation was carried out by a sprinkler system laid along the green spaces, between waterings the soil looked equally dry.
Simha Blass (right) and Eric Johnston
The hydraulic engineer decided to check the condition of the soil near the trunk of the bush and, digging to the length of the shovel, found out the reason – the drops of water from the leaking pipe joint moistened the top layer of the soil only slightly, but in the depths the soil was much more moistened. And the area of moistened soil reached the root system of only this bush. It was Simha Blass who, in the course of further experiments, created the first drip irrigation system..
How the drip irrigation system works
Its main elements are droppers (emitters), a supply hose, switches and a master block..
Drip irrigation system diagram:
1 – distribution pipeline; 2 – irrigation pipeline; 3 – dropper.
A dropper (average price – 10 rubles) is a device that is cut into the supply hose next to each plant and supplies a certain volume of water to the plant roots in portions (drop by drop). By design, droppers can be collapsible / non-collapsible, adjustable (controlled water flow) and non-adjustable, end (mounted at the end of the hose (pipeline)) and straight-through (mounted in a specially made hole).
In addition, droppers are classified into:
- ordinary and compensated. Their second type is capable of adjusting to an increase / decrease in pressure in a certain range and is intended for a complex landscape, replete with level drops – regardless of height differences, compensated droppers will supply plants with a certain amount of water;
- by the volume of water supply (from 1 l / h and above);
- equipped and not equipped with anti-drainage system (CNL). In the first option, the efficiency of impulse irrigation is higher, since the likelihood of drainage and unplanned filling is excluded;
- with the installation of a spider-type dispenser (average price – 80 rubles) (it allows you to bring drip irrigation to several points remote from the supply hose at a certain distance) and without this possibility.
The delivery hose can be a tube or tape. Tubes (average price – 15 rubles / running m) are made of pvc, diameter 16-20 mm, wall – 100 μm-2 mm, droppers are either overhead (cut-in) or built-in. Drip lines (tapes) (average price – 10 rubles / running m) are also made of polyethylene, which is rolled up into a tube and then glued / welded. The largest drip line manufacturers produce seamless drip lines. Micropores inside such lines play the role of a kind of labyrinth that changes the water flow and creates turbulence in it, which is necessary for accurate dosage of irrigation. Drip tapes are equipped with built-in drippers with a pitch of 100 mm and higher. Drip line wall thickness is specified by manufacturers in mils (1/1000 in) and starts at 5 mils (0.127 mm or 127 microns), the largest wall thickness is 15 mils (0.381 mm or 381 microns).
Switches (taps) (average price – 35 rubles) – with their help, water is supplied to a certain drip line.
Masterblock – a complex consisting of a pump and a filter (the average price of a pump + filter complex is 4,000 rubles). The task of the pump in the master block is to reduce the water pressure (if necessary) and supply it under a pressure of no more than 1.5 bar. When using a water tank for water, a filter is required (average cost – 700 rubles).
In addition to the described elements of the drip irrigation system, you will need tees (35 rubles / piece) and connectors (20 rubles / piece), adapters (50 rubles / piece) and couplings (150 rubles / piece), made only made of plastic (rust will clog the drip nozzles).
Drip irrigation system – design
An integral part of any design is creating a plan on paper, and we’ll start with it. It is required to draw up a watering scheme by drawing beds and other plants, while indicating the sizes. Then, a scheme for the installation of drip irrigation is planned, the starting point here will be the location of the container with water (water source). By the way, if a container with water is used, it must be raised above ground level by one or two meters to achieve the required water pressure in the system. Regardless of the source of water and its quality, a water filter must be installed between it and the main (main) pipe.
It is necessary to calculate the volume of water consumed through the future drip irrigation system in one hour. On average, droppers release 5-7 liters of water into the soil per hour (depending on the model) – we calculate the step of the droppers, their total number and get the required volume of water. For example: a drip tape 100 m long, with a 300 mm dropper pitch – there will be 334 droppers in total. Water outlet from each (conditionally) – 5 liters per hour, respectively, all droppers “drip” 1,670 liters of water per hour, ie. 200 liter capacity is not enough. Here, either dilute the drip system with two irrigation zones, or look for a constant source of water.
The connection of hoses with droppers or drip tapes with the main pipe is carried out through taps (you cannot do without fum tape), if necessary, to expand the irrigation system, connectors and tees are cut into it. Let me remind you – all elements of the drip irrigation system must be made of plastic (not metal)! The end of the main hose, the ends of drip tapes and hoses with droppers will need to be plugged – either with special plugs or with a rubber band (as an option, with wire). If the relief of the irrigation area has a certain slope, then drip tapes and hoses are displayed under the slope, main hoses – only horizontally.
Drip tapes and hoses are buried (up to 150 mm deep), laid on the ground, or suspended above the ground using supports. In the first case, a drip hose or tape with the greatest wall thickness is required (they will have to resist plant roots), in the rest, the walls, in order to completely exclude water bloom, must be opaque.
Selection of elements of drip irrigation system
The main “working” elements of drip irrigation – drip tubes and lines, droppers and dispensers are selected for a specific plant culture, they are not universal!
“Spider” dispensers are convenient for perennial plants grown in greenhouses. They are not suitable in open field vegetable growing – the step between the dispensers should not be less than half a meter, therefore, a full supply of plants in the beds with water will not work. In addition, main water pipelines for such dispensers can only be suspended, and the “spiders” themselves are not cheap.
For vegetable growing, drip lines are excellent, you just need to choose a certain step between the droppers: vegetable crops with a small root crop (carrots, onions, etc.) – 200 mm; most of vegetable crops – 300 mm; melons – 1000 mm. When deepening the drip line underground, it is better to choose the type with the largest wall thickness.
The choice of the model of the dropper (emitter) of the drip line is related to the needs for watering vegetable crops and the rate at which water seeps in a given soil.
Drip line installation
It is much easier and more convenient to carry out installation work on the formed beds before the actual planting of vegetable crops. We take in hand the drawn plan and proceed:
- we lay the main pipe made of pvc, we cut it according to the plan – special scissors will be needed, cutting is done strictly across the pipe. Then you need to leave the pipe on the site – let it rest for several hours in the sun;
- mark the holes with a marker (felt-tip pen) – all mounting points must be on the same line. The holes are drilled with a wood drill, the diameter of the drill for the size of the adapter (in the range of 14-16 mm) – drill carefully, otherwise the drill will go through the pipe;
- collect the main pipe through the fittings, connect it to the water supply through the filter. The elements of the main pipe should be inserted into the fittings until they stop – for the best sealing. Do not close the end holes at this stage of installation;
- the line of flushing the main pipe (prerequisite!). Apply pressurized water to remove any plastic chips and debris trapped in the pipe while drilling holes. Then plug the end holes with wooden plugs;
- installation of fittings for drip tapes. Insert seals into the cut holes, force fittings into them – this procedure will be simplified by heating the holes with a hairdryer;
- installation of drip tapes. Attention: dragging and stretching tapes on the ground is prohibited! Connect the tapes to the fittings (sealing the connection with fum tape), making sure that the tape faces upward in a “labyrinth” (the “labyrinth” area is painted with one or two parallel lines and has a small visible gap along the entire length of the drip tape). Cover the opposite end with plugs – fold the end of the drip tape towards the fitting, secure with a rubber ring (wire, tape);
- trial run. Run water into the main pipes, alternately switching them and checking if water is flowing. Check the uniformity and depth of soil moisture at each irrigation point, determine the frequency of irrigation.
DIY drip irrigation
You will need a water tank of 100-200 liters, raised a meter from ground level. If it has a lid, holes need to be made in it; in the version without a lid, the container is covered with two-layer gauze (it is necessary that air enters it). At the very bottom, you need to make a hole, the diameter of which coincides with the diameter of the main (irrigation) hose. A plastic tap-tip (or a fitting for two hoses) of the corresponding diameter is installed in the hole made, the main hose is attached to it – fastening through a clamp. Seal the hose outlet with a wooden plug.
The main hose extends over the rows of beds, it should be raised above ground level by 150-200 mm – the wire is pulled on the posts, to which it is attached. A hole is made in the hose above each plant (use a d 2 mm nail, holding it with pliers), into which a piece of wire is inserted – with its help, drops of water will be directed to the roots of the plants.
The main problem with such a drip irrigation system is clogging of the outlet openings. They can be cleaned using the wire guides or blowing out the hose (removing the guides).
Drip irrigation – advantages and disadvantages
- achieving high yields. The soil is not waterlogged, which allows plant roots to “breathe” unhindered and develop the root system. The roots of plants irrigated by the drip method actively capture the cone-shaped zone of moisture, developing root hairs and intensively absorbing nutrients along with water;
- plant nutrition. Fertilizers dissolve in water for irrigation and go exactly to the roots, thereby increasing the efficiency of fertilizing. In arid climates, there is no better way to fertilize plantings;
- in comparison with sprinkling, the leaves of cultivated plants are not moistened with drip irrigation, thereby reducing the risk of diseases, there is no flushing of fungicides and insecticides from the foliage;
- dry areas between rows of plants allow easy harvesting, spraying and tillage. Drip irrigation of plants planted on slopes and topographically difficult areas does not cause soil erosion;
- tangible savings in water. Watering only the root zone, which will not exceed 60% of the total area of the site, minimal water evaporation.
- reduction in physical costs. A properly designed drip irrigation system acts independently. All that is required for it is a permanent (replenished) source of water.
- periodic clogging of droppers with salts and impurities contained in the water. Water needs to be defended and filtered;
- from time to time it becomes necessary to adjust the water flow rate of each of the droppers;
- outdoors, drip tapes and hoses (tubes) can be damaged by insects, rodents and birds – a number of measures are required to counter this threat.
In terms of its quality characteristics, drip irrigation is second only to aeroponics.
How to operate a drip irrigation system
The main problem for gardeners with this irrigation system is clogged drippers and hoses. You can determine the blockage by the absence of a wet spot under one / several droppers (spot diameter with high-quality work is 300-400 mm). If one dropper is faulty, it should be replaced.
The cause of the blockage can be mechanical, biological or chemical. From the first – clogging with silt, sand, etc. – filters will fight, they must be cleaned once a month (the exact frequency depends on the degree of contamination of the water for irrigation). To eliminate the causes of biological contamination (green algae, plaque and mucus), rinsing with clean water under pressure and chlorination will help. Chemical fouling is caused by water hardness and fertigation (the introduction of fertilizers into the water for irrigation) – acid additives that keep the pH value within 5-7 will help. It is recommended to use those additives that are approved by the manufacturer of this drip system..
During work on the beds, the drip line may be damaged by a garden tool – it is necessary to cut it perpendicularly and reconnect using a bi-directional connector (afterwards, do not forget to rinse this area with water).
After harvesting in the fall, you should rinse and completely disassemble the irrigation system, removing water from it. Dried drip tapes and hoses (pipes) are stored in utility rooms.