Drip irrigation is the most efficient micro-watering system known for its water and nutrient-saving properties. The system is made up of a network of valves, drip lines or dripperlines, pipes, and emitters that are installed on top of or under the soil. The emitters are spaced evenly along the pipe and are designed to slowly release water in a drip or trickle directly to the base of the plant, irrigating the root zone rather than the soil.
Why is drip irrigation so efficient?
There are many reasons why drip irrigation is considered one of the most efficient and environmentally sustainable irrigation methods on the market today. For example:
- This system can be used for recycled or treated wastewater, as regulations do not permit spraying water that doesn’t meet potable water standards in the air.
- Delivering water directly to the base of the plant reduces evaporation and the risk of some diseases from airborne delivery.
- Precise and slow delivery means the right amount of water is dispersed at the right time with no run-off or waste.
- Liquid fertiliser can be pumped through the system and delivered with irrigation water, resulting in fertiliser savings.
- Although the initial cost of a drip system may be higher than some other irrigation methods, growers should consider the return on investment given that drip systems deliver significant savings on inputs such as water, fertilizer, energy, and labour, while improving crop yields and quality.
How does it work?
The system is made up of a number of components including a pump or pressurised water source, a filtration system, a backwash controller, pressure control valve, distribution lines, valves (pressure, air release, and isolation), drip lines, or poly tube and emitters, poly fittings and accessories.
Water is pumped directly from the water supply which then travels through the primary filtration system to remove any fine particles that could block the emitters or drip lines. At this point, there is the option of adding a chemical injection fertiliser system. The water is then pumped into the field through a secondary filter and various valves to the drip line laterals and emitters.
What is an emitter?
The emitter or ‘dripper’ is the final piece in the drip irrigation system. Drippers are either welded inside the drip line during the extrusion process or they come as individual pieces that can be attached directly to a lateral pipe where needed. There are numerous variations and features, such as pressure-compensating or non-pressure compensating, anti-siphon, anti-drain, extra root resistance, to name a few. Each dripper is designed to discharge water at a very uniform flow rate under a specific range of pressures. Selecting the right dripper is dependent on the crop requirements, topographies, water quality, and applications (i.e. above surface or sub-surface).
Where is it used?
Any crop can be grown using drip irrigation. From field crops such as maize, soybean or sugarcane, to vegetables, vineyards, tree crops, and greenhouse crops. Either growing in soil or in a soilless media. On a flat field or on sloping terrain – drip irrigation fits all topographies. The only decision is choosing the right drip configuration based on your crop and field conditions. Drip irrigation is also well suited for domestic use and is commonly used under lawns, in flower beds, vertical gardens, and pot plants.
Advantages of drip irrigation
- Precise water and nutrient delivery at the base of the plant
- Reduced water and fertiliser waste due to drip delivery method
- Less risk of erosion
- No need to level the field
- Irregularly shaped fields can be accommodated for 100% land utilization
- Lowered risk of plant disease because water is delivered at the base and doesn’t touch the foliage
- Energy savings as drip systems work on lower pressures
- Higher and more consistent quality yields
- No saturation and good soil aeration
- Avoids high salinity caused by excessive fertilizer application
Disadvantages of drip irrigation
- The initial cost can be higher than other irrigation systems
- Water must be filtered to avoid clogging
- Requires a better understanding of irrigation scheduling and system maintenance
- Can lead to a build-up of salt at the edge of the wetting pattern
- Pipes and tubes are susceptible to rodent damage
- Cannot be used for night frost damage control
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