Soil is permanently underlying processes of degradation, erosion and formation. In a natural equilibrium, the processes are balanced and lead to a permanent “refreshment” of the soil quality and quantity. The processes are highly depending on  external factors:

• rock type (bedrock),
• climate,
• vegetation,
• relief,
• time.

Each factor underlies also changes at different time levels and these changes consequently disturb the equilibrium. As result soils either erode and degrade or form new. Erosion, soil erosion and degradation is a relative quick process, whereas soil formation takes rather long. At a certain stage of degradation, soil formation is not possible anymore.

Soil forming processes a rather complex: they are depending on weathering processes, climate and land formation.

Weathering, climate, and rocks: What differences in the thickness of soil occur in: (a) tropical and arctic soils, above sandstone and limestone, on flat and steep slopes?

The location on a landform influences soil formation and erosion.

 

Factor	Soil development
Climate	Deeply weathered soils in the tropics, shallow soils under a tundra surface
Rocks	Sandstone: less developed soils; limestone: deeper soils
Slope	Steep slopes, thin soil layer; flat to gentle slope, deep soil
Landform	well drained summits; well drained midslopes, material and nutrient washout causing thin layers; foot slopes: accumulation and soil development