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A Few More Soils Tips…. Envirothon. How does Parent Material Convert to Soil?. 4 main processes: Additions Losses Translocations Transformations. Additions. Occur because … Organic material decays Floods bring in silt Wind blows in loess. Losses. Most commonly occur by leaching
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A Few More Soils Tips…. Envirothon
How does Parent Material Convert to Soil? • 4 main processes: • Additions • Losses • Translocations • Transformations
Additions Occur because … • Organic material decays • Floods bring in silt • Wind blows in loess
Losses Most commonly occur by leaching • Minerals dissolve in water and move out of the soil • sodium salts, gypsum, and calcium carbonate, are relatively soluble and leach easily • Quartz, aluminum, iron oxides, and kaolinitic clay weather don’t leach easily and become the main components of highly weathered soil. • Nitrogen & Potassium are water soluble – leach
Losses • Also due to • Erosion (solid materials) • Gas evaporation – Oxygen, Carbon Dioxide, Nitrogen
Translocations Movement of soil material from one place to another. (Physical Changes) • Usually because minerals dissolve in water and water table can move up or down leaving salts in different layers of the soil. • Hardpans formed this way
Transformations • Chemical changes occurring in soil • Caused by microorganisms • Weathering changes minerals • Reduction of Iron Oxides (red mottles) in hydric soils (grey mottles)
Soil Properties • Cation Exchange Capacity – ability of a soil to hold onto cations. • Important plant nutrients such as Magnesium, Potassium, Iron, Ammonium are cations! • Available Water Capacity • Determined by texture, content of rock, depth of roots, organic matter, compaction
Soil Properties • Soil Structure predicts permeability Most to Least • Granular • Prismatic • Subangular Blocky • Platy