Micro irrigation technology

Micro irrigation is a method of irrigation in which water and nutrients required for crop growth are evenly and accurately delivered to the soil surface or soil layer near the roots of crops at a small flow rate through a low-pressure pipeline system and specially designed irrigators installed on the final stage pipeline according to the water requirements of crops. Compared with traditional ground irrigation and sprinkler irrigation that moistens the entire area, micro irrigation only moistens a small amount of soil near the root zone of crops with a small amount of water, hence it is also called local irrigation.

Micro irrigation can be divided into the following four forms based on the different ways of water flow during irrigation.
1. Drip irrigation
Drip irrigation is a form of irrigation in which water is evenly and slowly dripped into the soil near the root zone of crops through drip heads, holes, or drip irrigation belts installed on the capillary. Due to the small drip flow rate, water droplets slowly enter the soil. Therefore, under drip irrigation conditions, except for the soil moisture immediately below the drip head, which is in a saturated state, the soil moisture in other parts is in an unsaturated state. Soil moisture mainly infiltrates and diffuses through capillary tension.
2. Subsurface drip irrigation
Subsurface drip irrigation is a form of irrigation in which all drip irrigation pipes and emitters are buried underground. This irrigation method can overcome the defect of surface capillary aging, prevent capillary damage or loss, and facilitate field operations. Compared with underground infiltration irrigation and infiltration irrigation by controlling the groundwater level, the difference is still that only a part of the soil is wetted, so it is called subsurface drip irrigation.
3. Micro spray irrigation
Micro spraying is a form of irrigation that uses refractive, radiating, or rotating micro nozzles to spray water onto branches, leaves, or the ground below the tree canopy. Micro spraying can increase soil moisture and improve air humidity, playing a role in regulating the microclimate in the field. Due to the low working pressure and small flow rate of micro spray irrigation, only a part of the soil is moistened in orchard irrigation, so it is customary to classify this type of micro spray irrigation within the micro irrigation range. Strictly speaking, it does not belong entirely to the category of local irrigation.
4. Yongquan Irrigation
Spring irrigation is a form of irrigation in which a small stream of water is formed by a water gushing device installed on a capillary tube, and the water flows into the soil in a spring like manner. The flow rate of spring irrigation is larger than that of drip irrigation and micro spraying, generally exceeding the soil infiltration rate. To prevent surface runoff, it is necessary to dig a small irrigation pit near the water gushing device to temporarily store water. Yongquan irrigation is particularly suitable for irrigating orchards and afforestation.