Erosion-induced recovery CO_(2) sink offset the horizontal soil organic carbon removal at the basin scale  

作　　者：Lingxia WANG Xiaodong NIE Jiaqi LI Yaojun LIU Hui WANG Yazhe LI Zhongwu LI 

机构地区：[1]School of Geographic Science,Hunan Normal University,Changsha 410081,China [2]Institute of Interdisciplinary Studies,Hunan Normal University and Hunan Provincial Key Laboratory for Eco-environmental Changes and Carbon Sequestration of the Dongting Lake Basin,Changsha 410081,China [3]College of Environmental Science and Engineering,Hunan University and Key Laboratory of Environmental Biology and Pollution Control(Hunan University),Ministry of Education,Changsha 410082,China

出　　处：《Science China Earth Sciences》2024年第6期2019-2033,共15页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.U19A2047);the Natural Science Foundation of Hunan Province(Grant No.2023JJ20030)。

摘　　要：To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(2)at the basin scale,which encompasses the entire hydrological process.This study introduced an approach that combined a spatially distributed sediment delivery model and biogeochemical model to estimate the lateral and vertical carbon fluxes by water erosion at the basin scale.Applying this coupling model to the Dongting Lake Basin,the results showed that the annual average amount of soil erosion during 1980-2020 was 1.33×10^(8)t,displaying a decreasing trend followed by a slight increase.Only 12% of the soil organic carbon displacement was ultimately lost in the riverine systems,and the rest was deposited downhill within the basin.The average lateral soil organic carbon loss induced by erosion was 8.86×10^(11)g C in 1980 and 1.50×10^(11)g C in 2020,with a decline rate of 83%.A net land sink for atmospheric CO_(2)of 5.54×1011g C a^(-1)occurred during erosion,primarily through sediment burial and dynamic replacement.However,ecological restoration projects and tillage practice policies are still significant in reducing erosion,which could improve the capacity of the carbon sink for recovery beyond the rate of horizontal carbon removal.Moreover,our model enables the spatial explicit simulation of erosion-induced carbon fluxes using costeffective and easily accessible input data across large spatial scales and long timeframes.Consequently,it offers a valuable tool for predicting the interactions between carbon dynamics,land use changes,and future climate.

关 键 词：Water erosion Sediment transfer Lateral soil carbon loss Land-atmosphere CO_(2) flux Dongting Lake Basin 

分 类 号：X144[环境科学与工程—环境科学] S153.6[农业科学—土壤学]