In pressurized irrigation systems water is pressurised and precisely applied to the plants under pressure through a system of pipes.
There are many variations of pressurized irrigation systems but the two major ones are: drip irrigation systems and sprinkler systems. Among them, there are many variations depending on the type of field, the crop and the kind of water delivery fittings needed, but the components of the basic system remain the same. They consist of the control station where the pressure is applied; the mains and sub mains, which are pipes of differing dimensions; the manifolds or feeder pipelines; and the laterals or irrigating pipelines equipped with emitters (in drip irrigation systems) or other fixtures delivering water to plants or spray booms for forage and grains and centre-pivot systems (in sprinkler systems). Fertilizer injectors can be incorporated into pressurized irrigation systems to perform fertigation.
Pressurized irrigation systems have the potential to avoid the water loss related to surface irrigation increasing the open irrigation application efficiency from 45%- 60% to pressurized irrigation with efficiency in the range of 75% 95%. While open canals systems have high labour requirement for maintenance pressurised systems have skilled labourrequirements.
Pressurized irrigation systems need from one-tenth to one-quarter of the man hours canal systems require.Driven by needs to reduce labour input into agriculture and the love of high technology, pressurized irrigation systems are costly and out of reach of small-holder farmers in developing countries.
Water quality and energy are crucial to the sustainability of pressurized irrigation systems. Water with high dissolved minerals leads to frequent blocking of emitters. Routine maintenance is needed to unblock delivery fittings and to maintain pumps and fertigation units.
Pressurized irrigation systems range from sophisticated computer controlled setups with high start-up costs to moderate-cost systems that include bubblers,mini-sprinklers for orchards and micro-sprinklers. Their use has largely been confined to large farmers or in commercial farming.
Pressurized irrigation systems for small-holders have recently been popularized. Examples of lower-cost systems are drip irrigation with drip emitters, drip tape and porous-wall pipes, as well as the hand-moved hose basin system for trees, pipe distribution irrigation systems and hose-move sprinklers.