Over time human activity has the potential to disturb the local soil profile. As humans dig pits or ditches into the soil or introduce new stone structures they can affect the viable appearance of the soil at the surface.
Features such as pits and trenches over time become in-filled with material often different in nature than the surrounding undisturbed soil, including differences in texture (e.g. grain size) or colour. Buried structures such as walls and compacted stones can be brought to the surface by ploughing and are often brighter that the surrounding soil. Soilmarks are usually present after ploughing in the autumn or spring.