Figure 23 – cross section of Soil profile along a tree

5.3. Soil Forming Factors

There are five main factors which controls the operation of soil processes, namely (i) parent material; (ii) topography; (iii) climate; (iv)biological activity; and (v) time. Climate and biological activity active control factors while Time, Topography and Parent Material are passive control factors. Active factors are those which supply energy that acts on the mass for the purpose of soil formation.