ZHANG Xinbao^1,2, BAI Xiaoyong^2,3, LI Hao⁴, FENG Teng⁵, PENG Tao^2,3, YAN Dongchun¹, HE Yongbin⁶, BAO Yuhai¹, WANG Yangchun¹

(1.Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2.Puding Karst Ecosystem Observation and Research Station, Chinese Academy of Sciences, Guizhou, Puding562100, China; 3. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China; 4. Sichuan Agricultural University, Chengdu 611130, China; 5. Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Science, Changsha 410125, China; 6. Yunnan University, Institution of Yunnan Geography Research, Kunming 650223, China)

Abstract: The 137Cs contents in slope soil, depressions and pond sediments were analysis and compared to learn the sources of sediment in SW China in this paper. Results show (1) in small karst basin, where catchment area is lower than 0.5 km2 and its erosion of ground on karst slope is very slight, sediment yield is mainly from underground loss (fractured earth) and ditch bank erosion (trench walls soil); (2) in some karst basin, where ground erosion on slope is strong, sediment yield is mainly from slope ground loss (surface soil); (3) underground loss and ditch bank erosion are the main ways for sediment yield in small watershed and larger basins, respectively. And there is positive correlation between sediment yield contribution and drainage area; (4) there is no 137Cs contents in fractured earth and trench walls soil can be tested, therefore, sediment contribution between these two sources can not be to distinguished by 137Cs tracer method; （5）the multi-tracer technique was recommended to study sediment sources of karst basin;（6）if the contribution of sediment was distinguished between fractured earth and trench walls soil, the magnetic method and pollen methods would be recommended; and (7) to determine sediment volume in depressions, river beaches and pond sediments by137Cs tracer method, and to analysis sediment retention of different depressions, beaches and ponds and sediment transport ratio of rivers, combined with the data of runoff plots and hydrological station.On the basis of the identification of sediment sources, sediment delivery ratio and sediment load (or sediment yield), to determine the balance of basin sediment and establishment sediment yield mode of karst drainage basin combining research results of runoff plots.

Keywords: karst basin; sediment sources; transport; 137Cs content

EARTH AND ENVIRONMENT Vol.45, No.3, Tot No.317, 2017, Page 247-258