Irrigation is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. It has been a key aspect of agriculture for over 5,000 years and has been developed by many cultures around the world. Irrigation helps to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation is also employed to protect crops from frost, suppress weed growth in grain fields, and prevent soil consolidation. It is also used to cool livestock, reduce dust, dispose of sewage, and support mining operations.
There are two main ways that farmers and ranchers use agricultural water to cultivate crops: rain-fed farming and irrigation. Rain-fed farming is the natural application of water to the soil through direct rainfall, while irrigation is the artificial application of water to the soil through various systems of tubes, pumps, and sprays. Irrigation is usually used in areas where rainfall is irregular or dry times or drought is expected. There are many types of irrigation systems, in which water is supplied to the entire field uniformly. Irrigation water can come from groundwater, through springs or wells, surface water, through rivers, lakes, or reservoirs, or even other sources, such as treated sewage.
Some of the different types of irrigation include:
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Surface Irrigation: This is the oldest form of irrigation, also known as gravity irrigation, where water is distributed over and across land by gravity, with no mechanical pump involved.
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Localized Irrigation: This method applies water directly to the root zone of plants, either on the soil surface or directly into the soil, through a network of valves, pipes, tubing, and emitters.
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Sprinkler Irrigation: This method uses a system of pipes and sprinklers to distribute water over the soil surface.
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Drip Irrigation: This method applies water slowly and directly to the root zone of plants through a network of valves, pipes, tubing, and emitters.
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Centre Pivot Irrigation: This method uses a large sprinkler system mounted on a central pivot that rotates around a field to distribute water.
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Sub Irrigation: This method involves applying water to the root zone of plants from below the soil surface.
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Manual Irrigation: This method involves manually applying water to plants using buckets, watering cans, or hoses.
Irrigation and drainage improvements are not necessarily mutually exclusive. Often both may be required together to assure sustained high-level production of crops.
