Soil properties vary on all scales of observation. Nevertheless, we think of soils predominantly in terms of homogeneous material. To think in this way might be justified for the agricultural soils that have been homogenized by plowing. Such simplifications are useful in developing concepts and models. However, only minimum tillage or no tillage is applied to a large portion of agricultural land, and for most forest ecosystems, homogenization by plowing has never been done. Moreover, in acidified soils burrowing and homogenizing animals, such as earthworms, diminish. It is therefore worthwhile to study the heterogeneity of soils.