See more from this Session: General Soil Physics: II
Wednesday, November 3, 2010
Long Beach Convention Center, Exhibit Hall BC, Lower Level
The vertical and lateral movement of soil water by gravitational forces in the plant-root zone occurs principally through the macro-pores, while the redistribution and upward flow occur in the capillary soil matrix pores. The purpose of this study is to introduce equations to estimate the sorptivity and hydraulic conductivity K(θ) into capillary-matrix and non-capillary macro pores of soils. The proposed equations are based on experimental field basic infiltration rate and saturated hydraulic conductivity (Ks). Five alluvial (saline and non-saline clay) and calcareous soil profiles were investigated for applying the assumed equations. Water sorptivity was determined at saturation and un-saturation conditions using a derived equation and certain infiltration parameters. It was observed a decrease in S value with an increase in soil water content, particularly in clay soils. The K(θ) has been discriminated into macropore saturated K(θ)f, matrix saturated K(θ)sh, matrix vertical K(θ)h and lateral K(θ)L. The value of K(θ)f for macro pores remained smaller than those fore soil matrix pores in the studied soils. The contribution of lateral K(θ)L was evident in clay soils with markedly values in saline clay soil. The calculated values of vertical K(θ)h were 2.41-2.94cm.h-1in calcareous soils, and 0.71-1.32cm.h-1in alluvial clay soils. The assumed equations are applicable and useful to predict the sorptivity and hydraulic conductivities of soil matrix and macro pores for sandy loam and clay soils.