Subsurface irrigation with ceramic emitters: An effective method to improve apple yield and irrigation water use efficiency in the semiarid Loess Plateau

Apple trees consume a large amount of water, causing soil desiccation which reduces the land quality in the Loess Plateau. The development of efficient water-saving irrigation technology has become the main way to maintain apple production and prevent land degradation in this area. Subsurface irrigation with ceramic emitters (SICE) is an energy-efficient and water-saving technology for arid and semi-arid regions. However, the effectiveness of SICE for apple trees needs to be researched because of the special environment of the Loess Plateau. In this study, we determined the optimal buried depth of SICE tape, based on the soil water content (SWC), yield, water use efficiency (WUE) and irrigation water use efficiency (IWUE) of apple trees over a two-year field experiment. Results shown that SICE buried at a depth of 40 cm significantly improved new shoot length, yield, WUE and IWUE by 15.9%, 7.6%, 14.8% and 6.5% respectively compared to subsurface drip irrigation (SDI). Variations in SWC for SICE buried at a depth of 40 cm were smaller than those for SDI. SICE significantly enhanced yield through its ability to save water and increase soil temperature for apple trees. Our study shows that SICE did not only produce a suitable soil water environment and ensure stable growth of apple trees, but also saved more water resources.