Variability of Soil Water Retention Curves and Predicted Hydraulic Conductivities on a Small Plot

Soil water retention curves were measured on cores taken from five sites at six depths in a Bainsville clay loam soil. There were differences in both the shape and magnitude of the average moisture characteristic curves from one location to another in the 225m2 plot. Coefficients of variation ranged from 4.2 to 13 percent in the surface layers and from 2.4 to 6.5 percent in the deeper layers. There were no consistent trends in variability with respect to tensions from 0 to −500 cm H2O. Predicted and measured hydraulic conductivity functions were variable, often showing a 100-fold difference at a given water content. The measured K functions were steeper than those predicted, and the match between them was considered reasonable only at the lower water contents.