Inversion of Water Infiltration Processes in the Profile of Red Soil Based on ERT Technology
[Objective]Soil moisture movement is the main driving force of the material and energy transport in soil.However,the paths of soil moisture in soils are complex and difficult to comprehend.[Method]With the help of an electrical resistivity tomography(ERT),soil moisture infiltration processes in the vadose zone were captured for the forest land and farmland of the red soil from Quaternary red clay.[Result]The results showed that in the red soil region,ERT could realize the visualization of the soil moisture infiltration process in the soil profile of the red soil.There was a highly significant correlation(P<0.01)between the resistivity measured by ERT and the soil moisture measured by the oven drying method.The linear coefficients of determination between them were 0.72 for forest land and 0.53 for farmland.Land use types affected the mode and depth of soil moisture infiltration.With a 2 cm water head height and 100 L water injection volume,the infiltration depth of forest land was more than 80 cm,much deeper than that of farmland(50 cm).With the continued injection of water for 200 min,a preferential flow phenomenon was both observed for the two land uses.However,the preferential flow of forest land was more developed than that of farmland.The preferential flow of forest land moves down rapidly through macropores formed by plant roots and soil animal activities while the preferential flow observed in farmland moved to the deep layer intermittently mostly in the way of the finger flow.[Conclusion]Under the influences of disadvantageous factors such as complex soil layers,high background water content and high soil clay content,ERT technology still could successfully capture the occurrence and development processes of preferential flow in red soil area.
Electrical resistivity tomographyLand use typesRed claySoil moisturePreferential flow
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