This review presents and examines relevant information from existing spatial variability studies of soil water and solute transport properties. Although most of the information available allowed only a conventional statistical analysis (mean and variance) of the pertinent properties, the field studies of (Nielsen, Biggar, and Erh (1973)) and (Russo and Bresler (1981)) were also suitable for spatial structure analysis. Detailed structural analysis of the saturated hydraulic conductivity (K_s) of these two fields demonstrated how this type of analysis may reveal field characteristics that are not apparent from conventional statistical analysis.

Using the Akaike Information Criterion for model discrimination, the three-dimensional spatial distributions of lnK_s of both fields were shown to be described best by a spherical covariance function and a linear drift function. The Hamra field of (Russo and Bresler (1981)) had a much larger deterministic drift component and a smaller stochastic component than the Panoche field of (Nielsen, Biggar, and Erh (1973)). The stochastic component of lnK_s in the Bet-Dagan field possessed a large nugget variance (40 percent of total) and was characterized by an integral scale of J = 14.5 m, as compared with J = 8.1 m and a small nugget variance (13 percent of total) in the Panoche field.