SOILD

SOIL Discussions

SOILD

SOIL Discuss.

2199-3998

Göttingen, Germany

10.5194/soil-2019-94

Evaluating soil erosion and sediment deposition rates by the 137Cs fingerprinting technique at karst gabin basin in Yunnan Province, southwest China

Yanqing

¹ ² ³ Jiang

Zhongcheng

² ³ Chen

Zhihua

¹ Yu

Yang

⁴ Lan

Funing

² ³ Yue

Xiangfei

² ³ Liu

Peng

² ³ Rodrigo-Comino

Jesús

https://orcid.org/0000-0002-4823-0871

⁵ ⁶

China University of Geosciences, Wuhan 430074, China

Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, China

Key Laboratory of Karst Ecosystem and Treatment of Rocky Desertification, Guilin 541004, China

Department of Sediment Research, China Institute of Water Resources and Hydropower Research, Beijing, 100038, China

Department of Physical Geography, University of Trier, 54296 Trier, Germany

Soil Erosion and Degradation Research Group, Department of Geography, Valencia University, Blasco Ibàñez, 28, 46010 Valencia, Spain

No.2016YFC0502503

No. 2017GXNSFBA198037; 2017JJA150639y

National Natural Science Foundation of China

41502342

(2017–2019, awarded to Dr. Yang Yu)

20 01 2020

2020 1 16

2020

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

This article is available from https://soil.copernicus.org/preprints/soil-2019-94/

The full text article is available as a PDF file from https://soil.copernicus.org/preprints/soil-2019-94/soil-2019-94.pdf

Soil erosion is a global environmental problem that can lead to the loss of nutrients in topsoil layers, particularly in fragile karst environments where the low contents of organic carbon and steep slopes used to be key pedological and geomorphological factors. Researching the erosion and deposition rates in small watersheds is important for designing efficient soil and water conservation measures. In this research, the Dapotou closed catchment, a representative depression in karst gabin basin, located in the Yunnan province, Southwest China, was selected to assess the variation of soil erosion and soil sediment mobilisation at different hillslope positions using the 137Cs tracing technique. The results showed that the soil erosion rates in the shoulders, backslopes and footslopes were 0.87, 0.35 and 0.49 cm a−1, respectively, meanwhile the soil sediment rate in depression bottom was 2.65 cm a−1. The average annual soil erosion modulus of the complete hillslope was 632 t km−2 a−1, which confirmed in the serious gradation according to karst soil erosion standards. The soil deposition modulus reached up to 3180 t km−2 a−1. The sediment delivery ratio summarized 0.82 in the whole catchment according to the square of hillslope and depression bottom. To identify which factor could play the most important role, a Principal Component Analysis was conducted. The results showed 137Cs concentration of different soil depth at different hillslope positions were significant correlated with soil organic matter (SOM) and total nitrogen (TN) (P < 0.05). As the typical karst geomorphological types, these findings are expected to provide data support for the whole watershed soil erosion management and ecological restoration in this fragile karst ecosystem.