%0 Journal Article %A QIAN Qinghuan %A WANG Shijie %A BAI Xiaoyong %A ZHOU Dequan %A TIAN Yichao %A LI Qin %A WU Luhua %A XIAO Jianyong %A ZENG Cheng %A CHEN Fei %T Assessment of soil erosion in karst critical zone based on soil loss tolerance and source-sink theory of positive and negative terrains %D 2018 %R 10.11821/dlxb201811007 %J Acta Geographica Sinica %P 2135-2149 %V 73 %N 11 %X

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.

%U https://www.geog.com.cn/EN/10.11821/dlxb201811007