Uncorrected soil water isotopes through cryogenic vacuum distillation may lead to a false estimation of plant water sources

Successful use of stable isotopes (δ2H and δ18O) in ecohydrological studies relies on the accurate extraction of unfractionated water from different types of soil samples. Cryogenic vacuum distillation (CVD) is a common laboratory-based technique used for soil water extraction; however, the reliability of this technique in reflecting soil water δ2H and δ18O is still of concern. This study examines the reliability of a newly developed automatic cryogenic vacuum distillation (ACVD) system through a set of pure water extraction. The impacts of extraction parameters (i.e., extraction time, temperature, and vacuum) and soil properties on the recovery of soil water δ2H and δ18O were further assessed for the ACVD and traditional extraction systems (TCVD) systems. Finally, the potential influences of the CVD technique on the prediction of plant water uptake were investigated through a sensitivity analysis. We demonstrated that the ACVD system was reliable for recovering the isotopic composition..., The isotopic data are collected from both the laboratory and the field. This study assessed the CVD approaches for stable isotope analysis and plant water source prediction through the following consecutive experiments. Experiment (Ⅰ): 56 pure water samples of known isotopic values were extracted using the newly designed ACVD system. Experiment (Ⅱ): 225 soil samples containing various rates of clay particles were oven-dried, doped with deionized water, and cryogenically extracted using ACVD and TCVD systems. Experiment (Ⅲ): a sensitivity analysis of plant water uptake under four types of input data was performed among seven sites in China., , # Data from: Uncorrected soil water isotopes through cryogenic vacuum distillation may lead to a false estimation of plant water sources

Note on the data for the above experiments

| Sheet1) Figure 2 Hydrogen and oxygen isotope offsets between deionized (DI) water and the same water cryogenically extracted from rehydrated soils |
| :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Column 1, three soil textures for rehydration treatments: sandy loam soil from Loess Plateau, loam soil from Northeast Plain, and clay soil from Yunnan-Guizhou Plateau |
| Column 2, ACVD\_3h (ACVD: automatic cryogenic vacuum distillation) ...