Quantification of irrigation water transport processes in ZiZiphus jujuba garden using water stable isotopes

ZiZiphus jujuba,which is native to China,has become one of the main crops widely planted in the western Loess Plateau because of its drought and flood-tolerance,adaptability,and higher nutritional value of the fruit.The irrigation water infiltration in Z.jujuba gardens is complex,and understanding its mechanisms is essential for efficient water use and sustainable agriculture.This knowledge helps ensure the long-term success of jujuba cultivation.This paper describes a field experiment that investigates the infiltration process of irrigation water from Z.jujuba garden and quantifies the contribution of irrigation water to soil water at different depths using the MixSIAR model.According to the FC(Field water holding Capacity)of Z.jujuba,irrigation experiments with three volumes of 80%FC,60%FC,and 40%FC are set up in this study.The study finds that water retention is better in Z.jujuba garden soils with a higher proportion of coarse gravel in the soil particle composition.Soil water content exhibits a gradient change after irrigation,with deeper wetting front transport depth observed with increased irrigation water.Additionally,there is correlation between soil temperature and soil water content.The soil water in Z.jujuba garden generally exhibits a preferential flow signal in the 0-40 cm range.Below 40 cm,a piston flow pattern dominates.The rate of soil water infiltration increases with the amount of irrigation water.In the 0-40 cm range of the soil vertical profile,irrigation water was the main contributor to soil water.Z.jujuba demonstrated flexibility in water uptake,primarily absorbing soil water at depths of 0-40 cm.For optimal growth of Z.jujuba at this stage,40%FC irrigation is recommended.The results are expected to be valuable future irrigation practices and land use planning for Z.jujuba garden in arid zones,supporting sustainable agricultural development and water management.

Deformation of the Zhangjiazhuang high-speed railway tunnel: an analysis of causal mechanisms using geomorphological surveys and D-InSAR monitoring

On 18 January 2016,the Zhangjiazhuang high-speed railway tunnel in Ledu,Qinghai Province,China,underwent serious deformation and structural damage.A crack formed at the top of the tunnel and the concrete on the crown peeled off.As a result,the tunnel could not be operated for three months.In order to determine the types and spatial distribution of the landslides in the region and the surface deformation characteristics associated with the tunnel deformation,we used field geological and geomorphological surveys,unmanned aerial vehicle image interpretation and differential interferometric synthetic aperture radar(D-In SAR) surface deformation monitoring.Nine ancient and old landslides were identified and analysed in the study area.Surface deformation monitoring and investigation of buildings in several villages on the slope front showed that the tunnel deformation was not related to deep-seated gravitational slope deformation.However,surface deformation monitoring revealed an active NEE–SWW fault in the area intersecting the tunnel at the location of the tunnel rupture.This constitutes a plausible mechanism for the deformation of the tunnel.Our study highlights the need for detailed engineering geomorphological investigations to better predict the occurrence of tunnel deformation events in the future.