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| DOI：10.13522/j.cnki.ggps.2019340 |
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| Using Clay Content to Predict Water Infiltration in Sandy Loam Soils |
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XIA Tian, TIAN Juncang
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1. School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China; 2. Ningxia Research Center of Technology on Water-saving Irrigation and Water Resources Regulation, Yinchuan 750021, China; 3. Center of Engineering Research on Efficient Utilization of Water Resources in Modern Agriculture in Arid Regions (Ministry of Education), Yinchuan 750021, China
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| Abstract: |
| 【Background】Water infiltration from a ponded soil surface is a common process in irrigation and hydrological cycling, and its measurement and mathematical modelling could be dated back to more than one century ago. The available models can be grouped into physical, empirical and semi-theoretical models. Physical models derived from the Darcy’s law include the Green-Ampt model and the Philip model, and the semi-empirical models included those proposed by Horton and Singh and Yu. Empirical models derived from field observations include the Kostiakov model and its variants. As water infiltration is modulated by soil properties which in turn depends on soil texture and organic contents, there has been an increase in use of pedo-transfer function model over the past decade to estimate soil hydraulic properties.【Objective】 The aim of this paper is to investigate the feasibility and accuracy of using clay content to predict accumulative infiltration and advance of wetting fronts in sandy loam soils.【Method】 We first experimentally measured water infiltration into 11 soil columns packed under the same bulk density but with different clay contents. The measured data were used to derive the relationship between infiltration and the clay content.【Result】When the bulk density was 1.41 g/cm3, with clay content increasing from 4.51% to 12.03%, the time it took the wetting front to reach a depth of 45 cm increased from 103 min to 310 min and the associated accumulative infiltration decreased from 8 cm to 1 cm. It also found that the parameter describing the temporal change in advancing speed of the wetting front and the parameter describing the temporal change in accumulative infiltration both decreased with the clay content exponentially with R2>0.968.【Conclusion】The derived model for predicting water infiltration into sandy loam soils usingthe clay content was accurate, with the absolute errors less than 10%. |
| Key words: sandy loam soil; infiltration; clay content; steady-state infiltration; predicting model |
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