A new technique using the aero-infiltrometer to characterise the natural soils based on the measurements of infiltration rate and soil moisture content

Abstract. Infiltration rate (f) and soil moisture content (θ) are the important factors for water resources management. Accurate measurements of these factors are not so readily available in most farmlands since present measuring equipments are not really suitable. This paper proposes the measuring device that uses a simple method to measure the rate of water infiltration into the ground and to determine the percentage of water contained in the soil. The two empirical equations which formulated on the basis of power regression models of plotting f vs. air pressure dropping rate (P) and θ vs. P are proposed to evaluate the dynamic properties of soil-water and soil–air interface from a three-phase system. All the parameters in equations have physical meanings, and experimental data validation shows that the equations are sufficiently accurate. Aero-infiltrometer was used to measure both the variations of f and θ at three natural soil sites to contribute to operational water management issues and soil texture identification. In the future, new research opportunities on basic knowledge of air diffusion into the ground will contribute to more versatile techniques in measurement of water infiltration.