Pedogenesis or soil evolution (formation) is the process by which soil is formed.
Climate regulates soil formation. Soils are more developed in areas with higher rainfall and more warmth. The rate of chemical weathering increases by 2-3 times when the temperature increases by 10 degrees Celsius (20 °F). Climate also affects which organisms are present, affecting the soil chemically and physically (movement of roots, burrowing by animals).
The organisms living in and on the soil form distinct soil types. Coniferous forests have acidic leaf litter. Mixed or deciduous forests leave a larger layer of humus. Prairies have very high humus accumulation, creating a dark, thick soil.