Irrigation

Irrigation is the artificial application of water to soil or crop areas to assist in growing crops when rainfall is insufficient or irregular. It aims to provide adequate soil moisture during critical growth periods, improve yields, and stabilize production.

Historically, irrigation developed with ancient civilizations, including canal systems in Mesopotamia and public works in Egypt and the Indus Valley. In the modern era, advances in pumping, distribution networks, and irrigation technologies such as sprinkler and drip systems have improved efficiency and reach.

Common irrigation methods include surface irrigation (flood, border strip, furrow), sprinkler systems (sprinklers, center-pivot and lateral-move systems), drip or micro-irrigation, and subsurface irrigation. Each method has different water-use efficiencies, capital costs, and suitability depending on crop, soil, climate, and topography.

Management involves scheduling and delivering water to meet crop evapotranspiration while avoiding waterlogging, salinization, and waste. Tools include soil moisture sensors, weather data, and crop models. Water quality and source sustainability are important considerations, as is the integration of irrigation with overall water-resource planning.

Environmental and economic considerations include potential benefits such as higher and more reliable yields, and potential drawbacks such as groundwater depletion, salinization, leaching of nutrients, and energy use. Best practices emphasize efficiency and precision, including deficit or regulated deficit irrigation, drip and sprinkler optimization, and integrated water management. Globally, irrigation constitutes a large share of agricultural water use and plays a key role in food production.