Soil water movement and deep drainage through thick vadose zones on the northern slope of the Tianshan Mountain: Croplands vs.natural lands

作者：Fang-qiang Sun,Li-he Yin,Wu-hui Jia,Jun Zhang,Xiao-yong Wang,Li-feng Zhu,Xin-xin Zhang,Xiao-ping Tang,Jia-qiu Dong

摘要：Regional aridity is increasing under global climate change,and therefore the sustainable use of water resources has drawn attention from scientists and the public.Land-use changes can have a significant impact on groundwater recharge in arid regions,and quantitative assessment of the impact is key to sustainable groundwater resources management.In this study,the changes of groundwater recharge after the conversion of natural lands to croplands were investigated and compared in inland and arid region,i.e.,the northern slope of the Tianshan Mountain.Stable isotopes suggest that soil water in topsoil(<2 m)has experienced stronger evaporation under natural lands than croplands,and then moves downward as a piston flow.Recharge was estimated by the tracer-based mass balance method,i.e.,chloride and sulfate.Recharge rates under natural conditions estimated by the chloride mass balance(CMB)method were estimated to be 0.07 mm/a in deserts and 0.4 mm/a in oases.In contrast,the estimated groundwater recharge ranged from 61.2 mm/a to 44.8 mm/a in croplands,indicating that groundwater recharge would increase significantly after land changes from natural lands to irrigated croplands in arid regions.Recharge estimated by the sulfate mass balance method is consistent with that from the CMB method,indicating that sulfate is also a good tracer capable of estimating groundwater recharge.

發文機構：Xi’an Center of Geological Survey School of Water Resources and Environment Chinese Academy of Geological Sciences

關鍵詞：Land-useSoilwaterGroundwaterrechargeDeepdrainageUnsaturatedzoneAridregionsCROPLANDNaturallandGroundwatersurveyengineeringTianshanMountainChina

分類號： P64[天文地球—地質礦產勘探]