Non-rainfall water contributions to dryland jujube plantation evapotranspiration in the Hilly Loess Region of China

Abstract Non-rainfall water inputs (NRWIs) provide crucial water resources for dryland ecosystems in arid and semi-arid regions. However, little is known about the quantitative characteristics and formation of NRWIs, and the relative importance of NRWIs as water sources in a dryland jujube (Ziziphus jujuba Mill.) plantation in the Hilly Loess Region of China. The objectives of this study were to determine the characteristics of NRWIs during the jujube growing season with regard to amount, duration, and contributions to transpiration, evaporation, and evapotranspiration. Dew intensity and duration were monitored using dielectric leaf wetness sensors, Also sap flow, soil water content, soil temperature, and meteorological variables were measured during the 2017 and 2018 growing seasons. NRWIs were found to be composed of canopy dew (CD) and water vapor adsorption (WVAS) in the 0-5 cm soil layer, amounting to 75.218 mm in 2017 and 75.309 mm in 2018 (CD accounted for about 81% of NRWI). Daily average CD was significantly greater than WVAS (P