Environmental factors such as drainage, acidity, salinity, the availability of nutrients and presence of toxic elements influence the development of the humus form profile.
Environment factors determine the composition and productivity of the vegetation, they also determine the composition and activity of the animals, bacteria and fungi living in the soil layers. By means of vegetation, animals, bacteria and fungi the environmental factors influence the nature of the organic matter. This is further expressed in the organic matter cycle and the humus form profile. This mechanism makes it possible to place a humus form profile in an ecological context. Some examples from humus form profiles in their ecological context are given below.
Primary succession in dune valleys
Decalcification of the dune sand determines the development of the location when it comes to the primary succession of the vegetation in dune valleys. Although the soil unit does not change up to five humus form profiles can be distinguished in this series of succession. More details are given in the power point show successie in duinvalleien (in Dutch).
Acidification of brook valleys
Brook valleys are originally fed by seepage water. The large decline of the ground water level made these terrains susceptible to acidification. This change in environmental factors shows clearly in development of the humus form profile. More details are given in the power point show verzuring van beekdalgraslanden' (in Dutch).
Oligotrophication through acidification
Acidification of the soil or raised groundwater levels in fields which were originally fed by seepage water are circumstances in which litter or other dead plant materials can not easily decay. The decomposition of the organic matter is slowed down. Because of this the field becomes very poor in nutrients, which shows in the increase of the C/N and C/P rates.