Scaling the saturated hydraulic conductivity of a vertic ustorthens soil under conventional and minimum tillage

With the aim of setting up a simpli®ed method to measure hydraulic conductivity of structured soils at saturation, a method reported by Ahuja et al. (Soil Sci. Soc. Amer. J. 48 (1984) 699±702; Soil Sci. 148 (1989) 404±411), which also refers to the generalised equation of Kozeny±Carman and the scaling theory, is tested in this paper. Data were elaborated from hydraulic conductivity measurements Ks on undisturbed soil cores taken from three plots of a sloping vertic soil which underwent various tillage practices for many years. In particular, following the proposed methodology, the spatial distribution effective soil porosity f was ®rst obtained. Once the distributions of hydraulic conductivity at saturation were obtained, it was possible to correlate the spatial variability of hydraulic conductivity with the variability of the unique factor a scaled by effective soil porosity. Statistical elaboration indicated that the log-normal law is the one which best approximates the frequency distribution of scale factors ak and af. No signi®cant differentiations were noted between the distributions of parameters relative to different soil tillage systems. # 2000 Elsevier Science B.V. All rights reserved.