干热河谷冲沟系统土壤团聚体对优先路径的影响

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中文摘要：[目的]为探究金沙江干热河谷冲沟系统土壤团聚体结构对优先路径形成的影响，深化对冲沟系统土壤水分和溶质运移的认识。[方法]选取金沙江干热河谷活跃和稳定冲沟不同部位(集水区、沟头、沟床和沟底)为研究对象，基于染色示踪和形态学图像解析技术，提取土壤水平剖面优先路径。采用RDA、灰色关联和耦合协调度等分析方法探究土壤团聚体结构与优先路径的关系。[结果](1)稳定冲沟土壤团聚体稳定性高于活跃冲沟。除个别土层外，活跃冲沟＞0。25 mm机械稳定性团聚体(DR0。25)、水稳定性团聚体(WR0。25)、平均质量直径(MWD)含量均显著小于稳定冲沟(p＜0。05)，团聚体破坏率(PAD)和不稳定团粒指数(ELT)则呈相反趋势。冲沟系统由集水区向沟底延伸，土壤大团聚体占比减少，团聚体稳定性下降。(2)活跃冲沟优先路径数量和连通性优于稳定冲沟，冲沟系统由集水区向沟底延伸优先路径连通性变差。各部位以＞10 mm优先路径为主要通道。活跃冲沟Simpson指数较稳定冲沟增加3。12％，不同径级的优先路径丰富度高于稳定冲沟。(3)优先路径的形成和分布受土壤团聚体稳定性的影响，MWD和WR0。25与优先路径数量达到极强关联且影响最为显著(p＜0。01)。(4)冲沟系统由集水区向沟底延伸，土壤团聚体结构与优先路径的耦合协调性降低，整体上表现为沟头＞集水区＞沟底＞沟床。[结论]土壤团聚体结构是优先路径形成的重要驱动因素之一，优先路径的分布对干热河谷冲沟系统发育具有重要影响。

外文标题：Effect of Soil Aggregate on Preferential Path in Gully Systemof Dry-hot Valley

外文摘要：[Objective]To investigate the impact of soil aggregate structure on the formation of preferential pathways in the gully system of the dry-hot valley of the Jinsha River to enhance our understanding of soil moisture and solute transport in the gully system.[Methods]We selected different sections(i.e.,catchment area,gully head,gully bed,and gully bottom)of both active and stable gullies in the dry-hot valley of the Jinsha River as our research subjects.We used staining tracers and morphometric image analysis techniques to extract the preferential pathways from the soil level profile.RDA(Redundancy Analysis),gray correlation,and coupled coordination were used to explore the relationship between soil aggregate structure and preferential pathways.[Results](1)The stability of soil aggregates in stable gullies were higher than those in active gullies.Except for specific soil layers,the contents of mechanically stable aggregates(＞0.25 mm,DR 0.25),water-stable aggregates(＞0.25 mm,WR 0.25)and average mass diameter(MWD)in active gully were significantly lower than those in the stable gully(p＜0.05).The aggregate destruction rate(PAD)and unstable aggregate index(E LT)showed the opposite trend.As the gully system extends from the catchment towards the gully bottom,the fraction of large soil and the stability of aggregates all decreased.(2)The number and connectivity of preferential pathways in active gullies were higher than those in stable gullies.However,the connectivity of the preferential pathways in the gully system deteriorated as it extended from the catchment to the bottom of the gully.The preferential pathways with a diameter＞10 mm served as primary channel.The Simpson index of active gullies exhibited an increase by 3.12％compared to stable gullies,indicating a higher richness of preferential pathways across different diameter classes.(3)The formation and distribution of preferential pathways were affected by the stability of soil aggregates,and MWD and WR0.25 were strongly correlated with the number of preferential pathways and had the most significant influence(p＜0.01).(4)As the gully system extended from the catchment to the bottom of the gully,the coupling coordination between the soil aggregate structure and the preferential pathways decreased.Overall,the order of performance was as follows:gully head＞catchment area＞gully bottom＞gully bed.[Conclusion]Soil aggregate structure is an of the important driving factors for the formation of preferential paths,and the distribution of preferential paths has significant impact on the development of gully systems in dry-hot valleys.

外文关键词：

dry-hot valleygully systempreferential pathwaysaggregate structure

作者：

李珠宇、李志成、徐贵迁、段旭、张广贺、赵洋毅

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作者单位：

西南林业大学生态与环境学院,昆明 650224

国家林业和草原局云南玉溪森林生态系统国家定位观测研究站,昆明 650224

关键词：

干热河谷冲沟系统优先路径团聚体结构

基金：

国家自然科学基金云南省农业联合专项面上项目云南省基础研究计划面上项目云南省青年人才专项云南省青年人才专项云南省自然生态监测网络项目

项目编号：

42067005202101BD070001-075202001AT070136YNWR-QNBJ-2019-215YNWR-QNBJ-2019-2262022-YN-13

出版年：

2024

DOI：

10.13870/j.cnki.stbcxb.2024.02.012

水土保持学报

中国土壤学会　中国科学院水利部水土保持研究所

水土保持学报

CSTPCD北大核心

影响因子：1.226

ISSN：1009-2242

年,卷(期)：2024.38(2)

参考文献量40