淤地坝坝地有机碳空间分布及其对流域土地利用的响应  

Spatial Distribution of Organic Carbon in Check-Dams and Its Response to Land Use in Watersheds

作　　者：孙睿哲 韩剑桥 李宗遥[4] 刘子涵 Sun Ruizhe;Han Jianqiao;Li Zongyao;Liu Zihan(The Research Center of Soil and Water Conservation and Ecological Environment,Chinese Academy of Sciences and Ministry of Education,Shaanxi 712100,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling,Shaanxi 712100,China;University of Chinese Academy of,Beijing 100049,China;of Soil and Water Conservation Science and Engineering,Northwest A&F,Shaanxi 712100)

机构地区：[1]中国科学院教育部水土保持与生态环境研究中心,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100 [3]中国科学院大学,北京100049 [4]西北农林科技大学,水土保持科学与工程学院,陕西杨凌712100

出　　处：《水土保持通报》2024年第3期379-389,共11页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金黄河水科学联合研究基金课题“黄土高原沟道水土保持措施阈值与布局”(U2243212);水利部重大科技项目(SKS-2022093);榆林市2023年科技计划项目(2023-SF-14)。

摘　　要：[目的]淤地坝以直接拦截泥沙的方式治理水土流失,显著改变土壤有机碳(SOC)的横向迁移过程。分析淤地坝坝地内SOC的空间分布特征及流域土地利用对坝地浅土层(0—200 cm)内SOC分布的影响,为淤地坝建设与流域生态环境协同发展提供科学依据。[方法]以岔巴沟流域内3个土地利用类型差异较大(草地、坡耕地、梯田面积占比不同)的小流域为对象,采用遥感解译、野外采样与室内测试相结合的方法,研究坝地SOC空间分布特征及坝地表土层SOC对土地利用的响应关系。[结果](1)在垂直方向上,SOC在表层土(0—20 cm)含量最高,并随土层深度增加快速降低,深层SOC含量变化较小,在3.5 g/kg上下浮动。(2)在顺水流方向上,因土壤侵蚀沉积特征等影响,SOC在坝地中、后段含量较高;在平行坝体方向上,两侧含量较高。(3)流域内梯田占比较高的B淤地坝,坝地SOC均值(4.4 g/kg)显著高于A淤地坝坝地(3.9 g/kg)和C淤地坝坝地(3.5 g/kg)。(4)流域内梯田的SOC最高,同时梯田建设影响了侵蚀泥沙的土壤粒径,从而使得流域内梯田占比与坝地表土层SOC呈显著正相关关系。草地表层SOC碳含量较低,使得坝地地表SOC含量与草地呈负相关关系。坡耕地SOC密度与坝地地表的SOC含量呈正相关关系,但由于坡耕地面积较小,其占比与坝地地表SOC无明显相关性。[结论]受土壤侵蚀、SOC来源和矿化特征影响,坝地表层土SOC最高,随土层深度增加快速降低并趋于稳定。梯田地类内的高SOC含量水平及较细颗粒的侵蚀土粒特征,导致了梯田占比最高的B淤地坝坝地内SOC含量最高。黄土丘陵沟壑区坝控流域内的梯田建设对淤地坝坝地SOC的正向响应。梯田及淤地坝不仅能够减少流域内的水土流失,同时还能够显著提高流域内土壤有机碳水平,改善流域微环境。[Objective]Check-dams are used to directly intercept sediment and control soil erosion,which could significantly change the lateral migration process of soil organic carbon(SOC).The spatial distribution of SOC at a check-dam site and the impact of watershed land use on the distribution of SOC in the shallow soil layer(0—200 cm)of the check-dam site was analyzed in order to provide a scientific basis for the coordinated development of check-dam construction and watershed ecological environment.[Methods]Three small watersheds with significant differences in the proportion of grassland,sloping farmland,and terraced land in the Chabagou catchment were investigated.A combination of remote sensing interpretation,field sampling,and indoor testing was used to study the spatial distribution characteristics of SOC in check-dams and their response to land use.[Results](1)In the vertical soil profile,SOC content was highest in the surface soil(0—20 cm),and rapidly decreased with increasing soil depth.The variation of SOC content in the deep layer was relatively small,fluctuating around 3.5 g/kg.(2)In the downstream direction of water flow,due to the influence of soil erosion and sedimentation characteristics,the SOC content was relatively higher in the middle and later sections of the check-dams.In the direction parallel to the check-dams,the SOC content on both sides was relatively higher.(3)The B check-dam with a high proportion of terraced fields in the watershed had a significantly higher mean SOC(4.4 g/kg)than both the A check-dam(3.9 g/kg)and C check-dam(3.5 g/kg).(4)The SOC content of terraced fields in the watershed was the highest,and the construction of terraced fields affected the soil particle size of eroded sediment,resulting in a significant positive correlation between the proportion of terraced fields in the watershed and the SOC content of the soil layer on the check-dam surface.The surface SOC content of grassland was relatively lower,resulting in a negative correlation between the surface SOC content o

关 键 词：淤地坝 SOC 土地利用 空间分布 相关性分析 

分 类 号：S157.31[农业科学—土壤学]