石漠化区岩-土与非岩-土界面土壤孔隙变异及入渗对干湿变化的响应  

Response of soil pore variation and infiltration to dry-wet changes at rock-soil and non-rock-soil interface in rocky desertification areas

作　　者：安迪 彭旭东[1,2,3] 戴全厚 刘婷婷[1,2] 曾庥 AN Di;PENG Xudong;DAI Quanhou;LIU Tingting;ZENG Xiu(College of Forestry,Guizhou University,Guiyang 550025,China;Institute of Soil Erosion and Ecological Restoration,Guizhou University,Guiyang 550025,China;Guizhou Karst Environmental Ecosystems Observation and Research Station,Ministry of Education,Guiyang 550025,China)

机构地区：[1]贵州大学林学院,贵阳550025 [2]贵州大学土壤侵蚀与生态修复研究中心,贵阳550025 [3]贵州喀斯特环境生态系统教育部野外科学观测研究站,贵阳550025

出　　处：《农业工程学报》2024年第11期139-149,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(42267054,42007067);贵州省科技支撑计划项目(黔科合支撑[2023]一般104)。

摘　　要：全球气候变化下土壤水分暴涨骤减愈加频繁和强烈,这使生态系统脆弱的喀斯特区石漠化适应性治理面临严峻挑战。因此,探究干湿变化下土壤孔隙变异及入渗响应对石漠化区土壤水分补给及降雨径流调节具有重要意义。该研究采用原位圆盘入渗法研究了干湿条件下不同露石岩面形状岩-土界面和非岩-土界面土壤孔隙结构变异及水分入渗的响应。结果表明:1)干旱条件下土壤孔隙大小及数量均大于湿润条件;干湿条件下岩-土界面土壤小(<0.2 mm)、中孔隙(0.2~1.0 mm)数及体积比均大于非岩-土界面,大孔隙(>1.0 mm)数及体积比则小于非岩-土界面;干湿变化下土壤孔隙数及体积比的平均变化幅度从高到低为小孔隙、中孔隙、大孔隙,土壤孔隙各参数平均变化幅度从高到低为非毛管孔隙度、毛管孔隙度、通气度、总孔隙度。2)干旱条件下土壤稳定入渗率和饱和导水率均大于湿润条件;随着水头压力的增加,岩-土界面和非岩-土界面土壤导水率逐渐增加,土壤稳定入渗率则呈现先减小后增大的趋势。3)干湿条件下各级土壤孔隙对入渗水流的贡献率均随孔隙减小而降低;非毛管孔隙度和大孔隙数对土壤入渗能力的影响最大。4)岩-土界面土壤孔隙及水分入渗等参数在干湿变化下的平均变化幅度均大于非岩-土界面。研究结果可为干湿变化下土壤孔隙变异引起的土壤水分补给及降雨径流调节能力变化的认识及石漠化的适应性治理提供科学依据。Against the backdrop of global climate change,the frequent and intense fluctuations in soil moisture have a significant impact on the dry and wet states of surface soil layers,posing severe challenges to the fragile ecosystem and rocky desertification management in karst regions.The soil in karst environments is vulnerable to frequent alternations between dry and wet conditions,leading to continuous shrinkage and expansion,which in turn affects the internal pore structure and infiltration capacity of the soil.To investigate the significance of soil pore variation and infiltration response under dry-wet conditions on soil moisture replenishment and rainfall-runoff regulation in rocky desertification areas,an in-situ disk infiltration meter was used to conduct experiments under four pressure heads(−0.5,−3,−6,−15 cm).The shape of the rock face,pressure head,and dry-wet conditions were taken as driving factors,the soil at flat,convex,concave,and complex rock-soil interfaces(closely adhering to the rock surface)and non-rock-soil interfaces(horizontally 20 cm away from the rock-soil interface)was taken as the research object.The size,distribution,and infiltration capacity of soil pores were studied,and the response of soil pore structure variation and water infiltration to dry-wet changes were analyzed.The results indicated that:1)Under drought conditions,the average non-capillary porosity of soil at rock-soil interfaces and non-rock-soil interfaces was greater than under wet conditions,and the average non-capillary porosity at non-rock-soil interfaces was greater than at rock-soil interfaces.The average change in soil porosity under dry-wet conditions,from highest to lowest,was non-capillary porosity,capillary porosity,air permeability,and total porosity.The number and volume ratio of soil pores under drought conditions were generally greater than under wet conditions.At rock-soil interfaces,the number and volume ratio of small pores(<0.2 mm)and medium pores(0.2-1.0 mm)were greater than at non-rock-soil interf

关 键 词：入渗 孔隙 土壤 干湿变化 岩-土界面 石漠化区 

分 类 号：S157.1[农业科学—土壤学]