水土保持研究2024，Vol.31Issue(6)：109-118,10.DOI:10.13869/j.cnki.rswc.2024.06.029
降雨条件下土壤胶结状况与团聚体分布特征研究
Study on Soil Cementation and Aggregate Distribution Characteristics Under Rainfall Conditions
摘要
Abstract
[Objective]The aims of this study are to analyze the influence of raindrop splash on the content of soil cement and the distribution characteristics of soil aggregates in the surface soil layer,and to reveal the relationship between the soil cementation status and the changes of aggregates under rainfall conditions.[Methods]Study on the content of aggregates cement in the sediment and the spatial distribution of topsoil aggregates were investigated by indoor simulated rainfall tests,physicochemical analyses and synchrotron radiation computer scanning(SR-µCT)technology.[Results](1)The order of the content of each cement in the sediment was calcium carbonate＞organic carbon＞free iron oxide＞free alumina＞six-carbon sugar.The content of the cement in the sediment increased with the increase of the raindrop diameter under the same thin-layer runoff.The content of the cement showed a fluctuating change of increasing and then decreasing with the increase of the thin-layer runoff under the same raindrop diameter.The combined effect of raindrop splash and runoff washout on the content of six-carbon sugar,free iron oxide,free aluminium oxide at＜0.053 mm particle size and six-carbon sugar,free iron oxide,calcium carbonate and organic carbon at 0.25～2 mm particle size was significant(p＜0.05).(2)Under the same thin-layer runoff,the total number of aggregates(A),the number of microaggregates(＜0.25 mm),and the specific surface area(SSA)increased with the increase of raindrop diameter in topsoil.The volume percentage of macroaggregates(Vmac),the number of macroaggregates(＞0.25 mm),and the geometric mean diameter(GMD)decreased with the increase of raindrop diameter.For the same raindrop diameter,with the increase of thin-layer runoff,the SSA decreased and the GMD increased.(3)The five types of binder in the sediment were significantly correlated with the structural parameters of the topsoil aggregates(p＜0.05).The higher the content of binder in the sediment,the larger the A and SSA,and the smaller the GMD and Vmac.[Conclusions]Raindrop splash thin-layer runoff increases the loss of topsoil aggregate cement migration and increases the cement content in the sediment.The decrease in topsoil aggregate cement content under rainfall erosion is the main reason for the structural damage and the stability decline of soil aggregates.关键词
雨滴击溅/薄层径流/胶结剂/团聚体微观结构Key words
raindrop splash/thin layer runoff/cementing agents/aggregate microstructure分类
农业科学引用本文复制引用
焦钒栩,侯卫亮,李光录..降雨条件下土壤胶结状况与团聚体分布特征研究[J].水土保持研究,2024,31(6):109-118,10.基金项目
国家自然科学基金"黄土高原土壤侵蚀过程中团聚体循环破坏机制和微观结构"(41571262) （41571262）
