HE Zhili1,2, YANG Yan1, 2, ZOU Xiaogang1,2, YOU Xianhui1,2, XIAO Wenjie1,2, ZENG Zhuzhou3
(1.Chongqing Key Laboratory of Karst Environment, School of Geographical Sciences, Southwest University, Chongqing 400715, China;
2.Field Scientific Observation ＆ Research Base of Karst Eco-environments at Nanchuan in Chongqing, Ministry of Land and Resources of China, Chongqing 408435, China.
3.Harmo Trust Agriculture Development Co. , Ltd, Chongqing 409800, China)
Abstract: The unique geological background of karst trough valleys restricts the spatial distribution and occurrence of groundwater. It is important for the desertification governance to explore the dynamic changes and influencing factors of water resource in rocky desertification areas. This study selected the Longtan Trough Valley in Youyang, Chongqing, as an example, and dynamically monitored and sampled groundwater in the trough valley from 2017-2019 to explore its temporal and spatial variation in different slopes of a typical karst trough valley under the control of rocky desertification. Results showed that groundwater in the trough area was sensitive to environmental changes, and that agricultural activities of varied degrees in the process of rock desertification control directly affected the dynamic characteristics of groundwater hydrochemistry. During heavy rainfalls, the peak concentrations of total Fe and Al3 + in the reverse layer slope flow were 1.3mg/L and 2.0mg/L, respectively, which were 13 times of those in the reverse slope karst spring, indicating the water and soil loss on the layer slope was serious. Rainwater on the slope carried soil particles and nutrients of the surface soil or other locations, such as fissures, crevices and pipes, into the groundwater system, and such rose the concentrations of K+, total Fe, and Al3+. Spatially, the confluence mechanism, soil layer thickness and vegetation conditions caused by different rocky desertification as well as the different "two-water" transformations on the reverse slope had significant effects on the spatial and temporal changes of groundwater in the study area.
Key words: rocky desertification; karst trough valley; sloping slope and reversed slope; groundwater
EARTH AND ENVIRONMENT Vol.48, No.3, Tot No.335, 2020, Page 358-368
