SOIL CHEMICAL AND PHYSICAL EFFECTS ON SPATIAL VARIABILITY OF HYDRAULIC CONDUCTIVITY

The influence of spatial variation in soil salinity and texture upon the spatial variability in hydraulic conductivity of a Kidman sandy loam soil was determined using a statistical technique based on linear regression and correlation analysis. Field-measured values of Ko and β were obtained by an approximate technique for estimating soil hydraulic properties that assumed K = Ko exp[β(o)}. Soil samples were analyzed for EC, SAR, and percentages of sand, silt, and clay. The variations in EC and percentage of sand were chosen as most influencing Ko and β. The variations in EC explained only 19 and 7% of the variation in Ko and β, respectively, and the percentage of sand explained about 3 and 15% of the variation in the same two parameters. Unspecified effects were responsible for about 75% of the variation in both Ko and β, suggesting that measurement methods or assumptions in developing K(o) were partially responsible. The results of the study were compared with a similar investigation of Ko variability in an Israel soil.