Fractal models of soil structure have not been explored in full. In particular, very little is known on the actual limits of prefractal behaviour of soil system. The objectives of the present work were (i) to estimate fractal scale limits from experimental bulk density - and porosity - aggregate size data sets and (ii) to search for links between fractal scaling limits and soil properties. A total of eighteen published data sets were used. They spanned a wide range of soil types and/or treatments. All the considered data sets covered more than two orders of magnitude in the independent variable (n>2), with a scaling factor ranging between b=1.66 and b=6.41. Both the maximum number of model iterations, imax, and n correlated positively with soil organic carbon. Knowing the limits of fractal behaviour, it is possible to make reliable predictions of soil physical properties at the scale of the representative elementary volume (REV).