Water saving potential and mechanisms of subsurface drip irrigation: A review

Subsurface drip irrigation is a water-saving irrigation technology with high water efficiency due to small irrigation volume and increased crop yield. Subsurface drip irrigation can effectively reduce evaporation and drainage and improve irrigation water productivity, whereas its' high degree of automation can reduce labor, operation, and management costs. This technique is an important irrigation technology in water-deficient areas in China. Here, we reviewed the development of subsurface drip irrigation technology, systematically compared the effects of various irrigation methods on crop yield, irrigation volume, and evapotranspiration, discussed the soil water movement process influenced by multiple factors under subsurface drip irrigation (from indoor control experiments and established mathematical models), revealed the water-saving and yield-increasing mechanisms of subsurface drip irrigation, and highlighted the key technical parameters of subsurface drip irrigation systems and their effects on crop yield and water use efficiency. Finally, we presented the difficulties of this system and called attention to the problems that required further research. This study examined the water conservation potential of subsurface drip irrigation and its underlying mechanisms, providing a scientific basis for promoting the widespread application of subsurface drip irrigation technology.