The last decade has seen innovative irrigation technological development. Initially developed and tested in a commercial irrigation environment this technology is now being applied to residential gardens. A recent Australian publication ‘Water Use Efficiency for Irrigated Turf and Landscape’ (Connellan 2013) is an important resource for practitioners that will benefit all gardeners.
Drip irrigation is based on delivering water directly to the root zone of individual plants. Only low volumes of water are required so the system can operate at low pressures and soil moisture can be optimised for the plant and soil type. The most important development is in pressure compensation within the emitters, providing greater reliability of volume despite variations in water pressure. Recent emitters also rely on turbulent, rather than laminar flow, which helps prevent blockage.
Advantages of drip emitters
- High efficiency of application
- Lower energy costs
- Minimal surface wetting
- Uniform application to individual plants is possible
Limitations of drip emitters
- High quality water is required or emitters will block up
- Soil water distribution is strongly dependent on soil properties
- High number of components and maintenance required
Drip irrigation technology was initially developed by the Israelis who irrigate their crops on less than 200mm of rain each year and use mostly recycled water. Drip irrigation systems are suitable for high intensity horticulture for valuable plants, high landscape value areas or fruit trees for instance. How well does it work? In the dry western areas of Melbourne hand watering 20 square metres of fruit trees requires 27,000 litres each year. Using drip irrigation under mulch would use 12,000 litres per year. (see www.smartgardenwatering.org.au)
What is your experience of drip emitters? Have you ever put a spade through one?