irrigation

n. act or process of artificially supplying an area land with water; application of liquid to a part of the body to cleanse or disinfect (Medicine)

Irrigation is the artificial application of water to the soil usually for assisting in growing crops. In crop production it is mainly used to replace missing rainfall in periods of drought, but also to protect plants against frost. Additionally irrigation helps to suppress weed growing in rice fields. In contrast, agriculture that relies only on direct rainfall is sometimes referred to as dryland farming or as rain fed farming. It is often studied together with drainage, which is the natural or artificial removal of surface and sub-surface water from a given area.
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n. irrigation, act or process of artificially supplying an area land with water; application of liquid to a part of the body to cleanse or disinfect (Medicine)

(n.)
The act or process of irrigating, or the state of being irrigated; especially, the operation of causing water to flow over lands, for nourishing plants.
  

Applying water or wastewater to land areas to supply the water and nutrient needs of plants.