Drip Irrigation is a method of watering plants/soil drop by drop at slow rates (around 1-20 liters per hour) for a longer duration. It is a kind of micro-irrigation system. It involves small diameter plastic pipes with emitters or drippers fitted at the places where the irrigation is required alongside the plants. Water can be supplied from either above the surface or from lines buried in the soil.
Drip irrigation is also called Trickle Irrigation.
Introduction to Drip Irrigation
The figure above depicts the trickle irrigation method in a very simple manner. The drip irrigation working model consists of a mesh or network of plastic mainlines interconnected with one other. Many sublines and lateral lines are connected to these mainlines. Emitters or drippers are attached to the orifices made along these lines through which water & other nutrients are supplied to the roots/soil directly.
This irrigation method produces higher growth and increased yield.
Types of Drip Irrigation System
While the underlying principle of trickle irrigation remains the same, the drip irrigation system can be broadly classified into 3 types:
- Porous pipe system
- Micro-Spray heads
- Pre-installed emitter lines
- Punch-in emitters
Porous Pipe System
In this system, a soaker hose is placed around the area to be watered. The same effect can be achieved by poking small holes in a normal hose pipe.
It is a cheaper option that can be easily set up.
It is suitable for smaller areas like home gardens, vegetable gardens, etc.
The pores tend to get clogged over time hence it is recommended not to bury the soaker hose in the ground but leave it on the surface.
In this system, the emitters are replaced by a spray head which wets a relatively larger surface area than the emitters. It is mostly used for trees or vines which have a larger root coverage area.
Pre-Installed Emitter Line Drip Irrigation System
In this irrigation system, the emitters are already pre-installed at equal distances along the length of the water lines.
This is by far the most common type of trickle irrigation method.
Usually, the emitters are placed between 12 to 36 inches apart.
This system results in lesser clogging events and is suitable for use in gardens and big crop fields.
Punch-in Emitter System
This is like a pre-installed system except that the emitters are not pre-fitted. You need to make holes as per your requirement & garden arrangement.
This is the most customizable system to suit your garden needs and I personally prefer this system for home gardens and container/pot gardening.
There are some advanced drip irrigation methods being developed around the world to improvise on existing methods & their drawbacks. One such method is Variable Rate Drip Irrigation. In this method, the water flow is automatically controlled depending on the moisture content of the soil. It requires a combination of advanced field monitoring systems like moisture level sensors, data from weather stations in real-time, etc.
Drip Irrigation Kit/System
A complete trickle irrigation system consists of multiple components connected together to form an irrigation kit. The following components form the major part of the drip irrigation equipment/fittings:
- Pump Station: Pulls water from the source & pushes it into the irrigation system at the right pressure
- By-Pass Assembly
- Control Valves: Maintain pressure in the whole system. It can be automatic or manual.
- Non-Return Valves (NRV): Prevent water from flowing backward in the system towards the source hence preventing contamination.
- Filtration System: Removes dirt & other unwanted substances suspended in water and prevents blocking & clogging of emitters and tubes.
- Fertilizer Tank/Venturi: Adds a controlled amount of nutrients into the system
- Pressure Gauge: Monitors the pressure to safeguard the entire system against high pressure. At the same time, it helps in controlling the amount of water supplied to the field. The typical pressure required is below 40 psi.
- Mains/Sub-mains: Supply water to the farmlands/fields from the water source.
- Emitting Devices: Supply water from mains/laterals/sub-mains to the plants. They come in many varieties and types.
- End caps: Stops water from flowing out of the system.
While the above components are essential for setting up a field irrigation system, you can skip a few components while setting up one for your home garden.
Drip Irrigation lines- Mainline, Sub-mains & Laterals
The lines are made of PVC or Polyethylene. They deteriorate under direct exposure to the sun & are hence buried in the ground to increase their lifespan.
The lines are normally buried about 6 inches deep in the soil.
Lateral pipes generally have a diameter between 13-32 mm.
It is a good practice to tie the pipes and lines with some support to keep them from moving or getting displaced due to factors like wind, animals, rains, etc.
Drip Irrigation Timer
This is required to automate the irrigation system. There are many commercially available timers available in the market.
Drip Irrigation Emitters
One of the most common problems with this method is the clogging of emitters. These emitters are usually 0.2 to 2.0 mm in diameter. Hence water needs to be filtered to avoid clogging.
These emitters can be classified into 2 types:
- On-line emitters – These are mounted on top of laterals or sub-lines (mainly used in groves & orchards where spacing and location are fixed)
- In-line emitters- These are an integral part of the water supply lines (mainly used for field crops, dense orchards, ornamentals)
Drip Irrigation Filter
There are many types of filters available in the market.
- Disc Filters
- Gravel Filter
- Hydrocyclone filters
- Media filters
- Screen filters
You can explore more on Netafimindia.com
Drip Irrigation Kit for Home Garden
Drip irrigation kits are easily available online. There are many affordable options available on online marketplaces:
Drip Irrigation Kits for Plants
You can manually control the water flow from the source when crops or plants need irrigation. The best time to water the plants is either in the morning or in the evening as evaporation is less and the temperature is lower facilitating better oxygen content in water.
The water flow can be automated by attaching a timer to the water source. These timers are available easily in the markets.
Frequency & duration of irrigation
The frequency and duration depend on the type of crop, type of soil, weather & climatic conditions as well as spacing between the emitters & flow rate of water.
Normally, you need to run the system at least once a week for 4-5 hours.
Watch this video to get an idea how to set up a system of your own:
Drip Irrigation in India
Some of the commercially available drip irrigation system suppliers in India are below:
The drip irrigation system has many advantages over the conventional sprinkler & surface irrigation methods.
Drip Irrigation Cost
The cost of drip irrigation in India varies between INR 35,000 to INR 60,000 per acre.
To read more about drip irrigation cost per acre, check out this article.
Drip Irrigation Advantages
In a drip irrigation system, water is applied right at the soil surface where plant roots are growing. The whole surface or area is not wetted. Hence the requirement for water reduces leading to water conservation. This conservation can be attributed to three reasons:
- Reduction in deep percolation (as only the right amount of water is supplied)
- Reduced evaporation (as the wetted surface area is smaller compared to other irrigation methods)
- Reduced water run-off (higher water absorption by soil due to slower rate of water supply)
Drip irrigation is done much more frequently than other types of irrigation hence maintaining a high soil moisture level. This helps in the faster growth of plants.
Also, there are lesser chances of water logging of roots and hence lesser instances of root rot/overwatering.
The benefits can be summarized as follow:
- Water conservation (greater than 60%). It has up to 95%-100% water use efficiency.
- Energy conservation. Reduction in energy costs up to 50%.
- Water is exactly delivered where required and the amount can be tailored to the plant requirement.
- This system can be installed on uneven surfaces as well. Hence no need to level the surface for irrigation purposes.
- Increased crop/plant yield (>200% increase in yield).
- Better plant growth.
- Faster crop maturity.
- Efficient automatically controlled fertilizer application thus eliminating labor cost & reducing cost of purchase of fertilizers.
- Cultivators/gardeners do not have to worry about overwatering/water logging.
- Prevention of soil erosion due to excess water run-off.
- When combined with a timer and a sensor system, irrigation can be automated and controlled from a remote location hence eliminating the need for physical presence.
- Can be easily used in irregular/ odd-shaped fields or areas.
- Improved germination of the seeds.
Drip Irrigation Disadvantages
Although the advantages far outweigh the negatives of drip irrigation, let us learn what are those considerations:
- The high initial setup cost: It requires a large investment initially to purchase the equipment and labor costs to set up the system.
- Leaking systems: Pests/rodents/garden equipment can bore leaks into the tubes.
- Emitter clogging: Since the orifices are small, clogging of these holes is common in drip irrigation systems and requires regular maintenance.
- Creates plastic waste.
Because of the initial high capital requirement, farmers normally use drip irrigation systems for high-value crops.
Drip Irrigation and Sprinkler System
Drip irrigation is best suited for places with water scarcity and for high-value crops. It can be used for other crops as well but the high initial setup cost is inhibitive for the farmers/gardeners.
The Sprinkler system, on the other hand, is a cheaper option and is easy to set up compared to the trickle irrigation system. It supplies large quantities of water in lesser time and hence is suited for places with water abundance.
Suitability of crops for Drip Irrigation Method
Drip irrigation is suitable for most crops ranging from fruits & vegetables to field crops. It is adaptable to many topographies. It can be used for growing orchard crops like grapes, bananas, Mango, Orange, Litchi, Guava, Pineapple & many more. It is also suitable for vegetable plants like tomatoes, chilies, onion, brinjal, etc., or flowering plants & tea/coffee plantations.
You can read more about trickle irrigation on this website.
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