Abstract:Numerous studies have been conducted on canopy interception and its influence on inter-rainfall isotopic composition and hydrochemical properties. However, little is known about how isotopic and hydrochemical characteristics chage in rainfall duration. The objective of this study was to understand the isotopic and hydrochemical characteristics of dwarfed jujube tree in rainfall duration. The water from stemflow, throughfall and rainfall in an open air were sampled continuously from two intra-rainfall events on Sept. 17—18 and Oct. 22—23, 2016 in the hilly and gully region of the Loess Plateau. At the same time, the volume of stemflow and rainfall in the open air were measured for four dwarfed jujubes of inter-rainfall events from July to Otc, 2016. The results showed that: (1) Average stemflow rates of dwarfed jujube was 2.3%~5.6% for inter-rainfall events; and stemflow was occurred when the rainfall amount reached 1.2 mm and 1.4mm during the two intra-rainfall evevts. (2) Relative to the rainfalls in the open area for two intra-rainfall events, the arithmetic-averaged δ2H of the throughfall and stemflow were enriched by 1.6‰~4.0‰ and 6.6‰~8.9‰, respectively; their arithmetic-averaged Cl- concentrations increased by 1.4~3.0 times and 13.3~13.4 times, respectively; their arithmetic-averaged SO42- concentrations increased by 1.5~2.7 times and 4.8~7.1 times, respectively. The throughfall and stemflow lagged behind the rainfall in the open area; during the intra-rainfall events, the delay was influenced by jujube tree canopy interception, the isotope was influenced by the prior period rainfall and further evaporation. The changes of hydrochemical components were gradually weakened with the increasing elapsed time since the start of a rainfall event.