Theory question 103
Rocks and Soil FormationList and discuss the process of soil formation.
Show the model answer
Model answer
Weathering of parent rock: physical (temperature changes, water, wind, ice), chemical (hydrolysis, hydration, oxidation, carbonation, solution) and biological (roots, animals, micro-organisms) break rock into fragments
Addition of organic matter: plants and animals die and decay; humus forms
Translocation: water moves materials down the profile (eluviation from the top, illuviation below)
Horizon (profile) development over time into O, A, B, C horizons
Factors controlling formation: parent material, climate, organisms, topography, time
Explanation
Cover weathering processes and how the profile develops.