Agricultural irrigation is the application of water to crops through artificial means. Irrigation is primarily used in areas with sporadic rainfall or potential drought conditions to ensure crop soil receives adequate water for cultivation. The water utilized in agricultural irrigation can come from various sources, such as groundwater, rivers, springs, lakes, wells, or surface water.
Manual irrigation is one of the most basic types of agricultural irrigation. Farmers or laborers use watering cans to saturate the crops by hand. Since manual irrigation is often time consuming and physically demanding, it tends to be used for small farms or in poverty-stricken areas.
Before advances were made in irrigation technology, surface irrigation tended to be the most implemented irrigation system for large scale watering. In surface irrigation, small canals are dug across the entire length of the crop area and water is poured at the top of the canals. Surface irrigation uses no pumps or other mechanisms and relies on gravity to distribute water across crops through the canals.
Sub-irrigation is a method often used for field crops such as peppers or tomatoes. The method applies water to crops from below the soil’s surface. A pipe system is buried beneath the roots of the crops and the water is pumped upwards into the roots to ensure the roots receive the correct water amounts.
To water crops from above, farmers may use the sprinkler method. Sprinkler agricultural irrigation uses overhead sprinklers or high pressure sprinkler guns to apply water to crop fields. There are also two types of specialized sprinkler irrigation: center pivot and lateral move.
Center pivot irrigation uses an automated system of sprinklers that are attached to fixed towers in the center of the crop area. The sprinklers rotate in a circular motion to evenly distribute water across the entire crop area. Center pivot is often used in flat, spacious crop areas.
While center pivot irrigation is a stationary sprinkler method, lateral move irrigation does not used centrally fixed sprinklers. A system of pipes is equipped with a wheel and sprinkler on each individual pipe. The sprinklers are either rotated mechanically by hand or can have a rotating mechanism built in. The sprinklers move across the fields and may require their water hoses to be reconnected or replaced as the sprinklers moves away from the original location. The lateral move agricultural irrigation tends to be more cost-effective than other methods but requires constant supervision.
Localized irrigation uses a low pressure system to gently water crops in small batches. A dripper can deliver water by drops directly to the root area. Water may also be applied through underground low pressure underground pipe systems. Since localized irrigation is so controlled, it can reduce the over application of water and prevent waste.