FRACTAL DIMENSION OF SURFACE-CONNECTED MACROPORE COUNT-SIZE DISTRIBUTIONS

The objectives of this study were (i) to investigate whether the value s of fractal dimension (D) can be used as an index to characterize sur face-connected macropore count-size distributions (MPCSD) in soil and (ii) if so, to explore functional relations between saturated hydrauli c conductivity (K-s) and D. The data on surface-connected, areal MPCSD , dry bulk density, and K-s for two soils under four tillage systems w ere obtained from published information. Values of D ranged from 1.47 to 1.81, depending on soil texture, tillage, and the depth in soil pro file. Values of D increased with increasing numbers of 1 to 2-mm size pores, and an opposite trend was observed with 2 to 4-mm size pores. T he K-s of layered soil profiles increased with increasing total porosi ty and decreasing D (R(2) = 0.94), both determined for depths below th e plow zone. The results indicate that values of D can be used as an i ndex to characterize surface-connected MPCSD in soil and to predict ma cropore flow in layered soil profiles.