Analytical Method for Estimating Soil Hydraulic Parameters from Horizontal Absorption
- DongHao Maa,
- QuanJiu Wang *bc and
- MingAn Shaobd
- a State Experimental Station of Agro-Ecosystem in Fengqiu, State Key Lab. of Soil and Sustainable Agric., Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
b State Key Lab. of Soil Erosion and Dryland, Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shannxi, China
c Institute of Water Resources Research, Xi'an Univ. of Technology, Xi'an 710048, Shannxi, China
d Northwestern Science and Technical Univ. of Agriculture and Forestry, Yangling 712100, Shannxi, China
Soil hydraulic properties are required to quantitatively simulate water and chemical transport processes in the vadose zone and groundwater with various numerical models. Most methods for determination of soil hydraulic properties are time consuming and expensive, which limits the application of the methods. The objective of this study was to develop an analytical method based on an assumption of exponential flux distribution to determine soil hydraulic parameters. Using this method, parameters of the Brooks–Corey model and exponential water diffusivity can be easily estimated from cumulative infiltration and wetting length vs. time in horizontal absorption experiments. The analytical method was tested and improved using 19 numerical soils in a wide range of textures. The results indicated that all the Brooks–Corey model parameters estimated by the improved method were very close to the simulated values. In addition, the water content, soil tension, and water flux distributions of three typical soils (clay, loam, and sand soils) estimated by the approximate solution of the improved method agreed well with those calculated by the HYDRUS-1D software as well as cumulative infiltration data. Therefore, although a large number of experiments are still required to test the method, it provides a simple approach to determine the hydraulic parameters of soils in a wide range of textures, providing a very good approximate solution to the problem of horizontal absorption.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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