EAES 101 Lecture Notes - Lecture 12: Soil Horizon, Pedogenesis, Soil Classification
26 Sep 2016
School
Department
Course
Professor
Document Summary
How is soil formed: the coffee analogue, zone of leaching. Ions from chemical weathering a: fine silts and clay infiltrate, zone of accumulation-lower soil profile. Ions form new minerals a: silts and clays clog pore spaces. More about soil and climate: climate exerts a dominant control on soil development, latitude, elevation. The soil profile: soil forms a vertical sequence of layers called a profile, profiles develop from the surface downward, weathering generates detritus, rainwater alters the detritus. 3: the upper horizons form topsoil, the only fertile part of the profile, easily removed by erosion, 1000s of years in the making. Soil horizons: distinct horizons reflect soil forming processes, o horizon-dark organic matter rich surface later, a horizon-organic and mineral matter, e horizon-transitional later leached by organic acids, b horizon-organic poor mineral rich later, c horizon-weathering bedrock. Soil classification: 12 soil orders are commonly recognized. Based on: soil mineral composition, environment of formation.
