Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (11): 2135-2149.doi: 10.11821/dlxb201811007

• 气候变化与地表过程 • Previous Articles     Next Articles

Assessment of soil erosion in karst critical zone based on soil loss tolerance and source-sink theory of positive and negative terrains

QIAN Qinghuan1,2(),WANG Shijie1,3,BAI Xiaoyong1,3(),ZHOU Dequan2,TIAN Yichao1,3,4,LI Qin1,3,4,WU Luhua1,3,4,XIAO Jianyong1,2,ZENG Cheng1,2,CHEN Fei1,2   

  1. 1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, CAS, Guiyang 550002, China
    2. School of Geography and Environmental Sciences, Guizhou Normal University, Guiyang 550001, China
    3. Puding Karst Ecosystem Observation and Research Station, CAS, Puding 562100, Guizhou, China
    4. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-01-15 Online:2018-11-25 Published:2018-11-22
  • Supported by:
    NNational Key Research & Development Program of China, No.2016YFC0502102 No.2016YFC0502300; "Western light" Talent Training Plan (Class A); Science and Technology Service Network Initiative, No.KFJ-STS-ZDTP-036; International Cooperation Agency International Program, No.132852KYSB20170029, No.2014-3; Guizhou High-evel Innovative Talent Training Program "Ten" Level Talents Program, No.2016-5648; United Fund of Karst Science Research Center, No.U1612441; National Natural Science Foundation of China, No.41571130074, No.41571130042; Science and Technology Plan of Guizhou Province of China, No.2017-2966


Traditional classic soil erosion models are not applicable in karst areas. In this study, the effective rainfall erosion threshold was obtained and the rainfall erosivity was re-estimated, according to the lithologic difference of the karst critical zone. The soil formation rate was calculated and used as the soil loss tolerance, based on the chemical composition variation of carbonate rocks. The spatial distribution information of karst depression was extracted by geomorphologic-hydrologic analysis, and the soil erosion algorithm in the karst critical zone was modified and improved. The results showed that: (1) The traditional algorithm ignored the specificity of the underlying surface of the karst critical zone. The average rainfall erosivity was estimated to be 47.35%, and the average rainfall erosivity in the karst area is only 59.91% of the non-karst area. (2) The soilless or less soil areas could be miscalculated as the high erosion region by using the conventional algorithm. However, the soil loss tolerance by continuous carbonate, carbonate clastic, carbonate and clastic interbeds were about 0.21, 1.2 and 2.89 t ha-1 yr-1, respectively. (3) Sloping lands and croplands in the depressions are generally regarded as the high incidence area of soil erosion, but the depression of the karst should be the sediment area of surface erosion. The spatial distribution of karst depression was basically coincided with that of carbonate rocks. (4) The traditional algorithm overestimated the soil erosion area at about 27.79%, while the soil erosion amount at approximately 47.72%. Generally, the traditional classic model could greatly overestimate the soil erosion amount in the karst area, therefore, an accurate and applicable model should be established. In addition, due to the slow soil formation rate, the thin soil layer and the less total amount of soil in karst area, the soil loss tolerance was far lower than the erosion standard of non-karst area. The classifying and grading standard and risk assessment method of soil erosion applicable to karst area should be set and established.

Key words: karst, rainfall erosivity factor, soil loss tolerance, depression sedimentary, theoretical soil erosion, actual soil erosion, southwest China