喀斯特地区含碎石土壤水分扩散能力  

Moisture Diffusion of Soils with Gravel in the Karst Region

作　　者：冯娅瑛 牟丽敏 周娜娜 韩珍 FENG Yaying;MOU Limin;ZHOU Nana;HAN Zhen(College of Forestry,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学林学院,贵阳550025

出　　处：《山地学报》2024年第2期185-195,共11页Mountain Research

基　　金：贵州省基础研究项目(自然科学)(黔科合基础-ZK[2023]—般065)。

摘　　要：中国喀斯特地区基岩裸露、土层浅薄,碎石(粒径>2 mm)在土壤中广泛分布,土壤水分迁移具有一定复杂性。已有研究多集中于水动力条件下土壤的垂直入渗分析,针对喀斯特含碎石土壤的水分水平扩散能力方面的研究鲜见。本研究以贵阳花溪区含碎石土壤为研究对象,通过水平土柱扩散法对比分析不同碎石含量(0、10%、20%、30%、40%)土壤湿润锋的前进状况以及土壤水分扩散率变化特征,探讨喀斯特地区不同碎石含量的土壤水分扩散能力。结果表明:(1)碎石含量相同时,湿润锋前进距离和前进速率与时间之间均呈幂函数关系;随着水分水平扩散的进行,土柱的体积含水率逐渐减小,玻尔兹曼(Boltzmann)变换参数λ则随着体积含水率的减小而呈指数增大;随着体积含水率减小,土壤水分扩散率呈递减趋势。(2)碎石含量不同时,湿润锋前进距离和平均速率随着碎石含量的增加总体呈现出增大趋势,但碎石含量为10%时湿润锋前进距离与平均速率均有所减小;同一位置的体积含水率随碎石含量的增加而增加;体积含水率相同条件下,土壤水分扩散率随碎石含量增加呈递增趋势。本研究结果可为喀斯特地区土壤水文循环和过程研究提供科学参考。Karst topography is primarily developed in southwestern China,heavily featured by shallow soil layers and exposed bedrock.Gravel(particle size>2 mm)are the regular components of the soil in karst areas,leading to complex soil moisture migration in the soil.Most previous studies focused efforts on vertical infiltration analysis of karst soils under hydrodynamic conditions,and little addressed to their horizontal water diffusion capacities.In this study,it experimentally investigated the soil moisture diffusion capacity of karst soils.Horizontal soil column diffusion experiments were designed to examine the progressive phases of soil wetting front and soil moisture diffusion rate for five sets of remolded karst soils with gravel contents of 0,10%,20%,30%,40%.(1)With the same gravel content of all soil samples,the advancement distance and speed of soil wetting front both had a power function relationship with time.As horizontal diffusion of moisture progressed,the volumetric moisture content of the soil column gradually decreased,accompanied by Boltzmann transformation parameterλincreasing exponentially,suggesting soil moisture diffusion rate decreasing simultaneously.(2)With the gravel content of soil samples increasing,the advancement distance and speed of soil wetting front generally show an increasing trend with the increase of gravel content,but both the advancing distance and average speed of the wetting front decrease when the gravel content is 10%.At the same location,volumetric water content increased with a higher gravel content,accompanied by soil moisture diffusion rate in descending trend of 40%>30%>20%>0>10%of gravel contents.The study would provide a experimental basis for understanding of soil hydrological cycles and processes in karst region of China.

关 键 词：碎石含量 水分扩散 湿润锋 喀斯特地区 

分 类 号：S157.1[农业科学—土壤学]