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INTRO TO SOILS – CH 2. Soil Origin and Development. THE SOIL BODY. Pedon – smallest body which can be called a soil Three-dimensional Typically extends down to depth of plant root. THE SOIL BODY. Polypedon – two or more contiguous pedons Form a Soil Series
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INTRO TO SOILS – CH 2 Soil Origin and Development
THE SOIL BODY • Pedon – smallest body which can be called a soil • Three-dimensional • Typically extends down to depth of plant root
THE SOIL BODY • Polypedon – two or more contiguous pedons • Form a Soil Series • Soil Series are the lowest official category in the soil taxonomy
THE SOIL BODY • Weathering of rocks and minerals forms pedons • Two types of weathering: • Physical weathering • Chemical weathering Eventually, a layer of young soil develops
THE SOIL BODY • Three types of rock: • Igneous • Sedimentary • Metamorphic
THE SOIL BODY • Five (5) Soil Forming Factors • Parent Material • Climate • Living Organisms (plant and animal) • Topography • Time
THE SOIL PROFILE • Soils change in response to their environment • Four processes of change: • Additions • Losses • Translocations • Transformations
THE SOIL PROFILE • As a soil ages these changes lead to formation of horizontal layers known as: • Soil Horizons These horizons may be exposed when digging into the soil revealing the: • Soil Profile
THE SOIL PROFILE • Master Horizons: • A, B, C • O, A, E, B, C, R Coded layers of horizon with distinct characteristics Not all horizons will always be present!
THE SOIL PROFILE • Subdivisions and Suffixes may further define the master horizons • e.g. AB, Ap, Bt, Bky See Appendix 3 for suffix explanations