THE VARIATION OF IN SITU MEASURED SOIL WATER PROPERTIES WITHIN SOIL MAP UNITS

Abstract

The in situ saturated hydraulic conductivities of nine soil units were measured and cores of the same soil were taken to the laboratory for determination of desorption water capacity relationships. Hydraulic conductivities for the coarse- and fine-textured soils were equivalent and higher than that for medium-textured soils. However, the coarse- and fine-textured soils showed measurably different desorption curves for each of three soil units tested. Variability of duplicate measurements of hydraulic conductivity at sites were found to be considerably less than that of the soil unit as a whole. The highly variable in situ hydraulic conductivities resulted in separations of two groups of soil with significantly different values. A third intermediate group was not significantly different from the other two. The desorption curves were discussed in relation to differences in pore size distributions, identifying proportions of the pore space attributable to structural pores and to textural pores.