Irrigation

Irrigation is the practice of applying controlled amounts of water to land to help crops, landscape plants, and lawns. Irrigation helps to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during times of below-average rainfall.
There are several methods of irrigation that differ in how water is supplied to plants. Surface irrigation, also known as gravity irrigation, as it is the oldest form of irrigation and has been in use for thousands of years. In sprinkler irrigation, water is piped to one or more central locations with in the field and distributed by overhead high pressure through a piped network and applies it as a small discharge to each plant.
Micro irrigation is a system that distributes water under low pressure through a piped network applies it as a small discharge to each plant.
Micro irrigation uses less pressure and water flow than sprinkler irrigation.
Drip irrigation delivers water directly to the root zone of plants.
Sub irrigation has been used in field crops in areas with high water tables for many years.
It involves artificially raising the water table to moisten the soil below the root zone of plants.
Irrigation water can come from ground water from surface water or from non-conventional sources like treated wastewater, desalinated water, drainage water or fog collection.
Irrigation can be supplementary to rainfall, which is common in many parts of the world as rainfed agriculture,or it can be full irrigation, where crops rarely reply on any contribution from rainfall.
Full irrigation is less common only occurs in arid landscapes with very low rainfall or when crops are grown in semi arid areas outside of rainy seasons.
Irrigation methods:
Surface irrigation
Micro irrigation
Drip irrigation
Sprinkler irrigation
Flood irrigation
Center point
Sub irrigation:
It has been used for many years in field crops in areas with high water tables.
It is a method of artificially raising the water table to allow the soil to be moistened from below the plants root zone.
Sub irrigation is also used in commercial greenhouse production, usually for potted plants. Water is delivered from below, absorbed by upwards and the excess collected for recycling.