Variation in soil volumetric water content across soil depth and δ18O content in UC and OC.

UC is the community under the P. euphratica canopy, whereas the OC is the community outside the P. euphratica canopy. UC and OC have three measuring plots, respectively. The Independent sample t-test is used to analyze the differences of soil volumetric water content between UC and OC. Different capital letters in each row indicate significant differences of soil volumetric water content between UC and OC. The measurement period of soil volumetric water content lasts from 5th to 8th August, 2010. During the time between 2:30 am to 6:30 am, 11∶30 am to 5∶00 pm at each experimental day, the soil volumetric water content recorded manually at intervals of 2 hours, while the time between 6:30 am to 9:30 am, 9:30 pm to 12:30 am, the soil volumetric water content recorded manually once an hour.Variation in soil volumetric water content across soil depth and δ18O content in UC and OC.