Soil consists of mineral matter, organic matter, air, and water Dead and living microorganisms, and decaying material Bacteria, algae, earthworms, insects, mammals, amphibians, and reptiles
Soil consists of mostly mineral matter varying proportions of organic matter Rest is pore space taken up by air, water, and other soil gases Parent material = the base geologic material of soil Mineral content Determines the starting composition of the soil
Organic matter includes living and dead microorganisms as well as decaying plant and animal material Water – is not pure, contains dissolved minerals and organics and is important for support of plant growth Air – soil air is not the same as air we breathe Soil can have an influence on a region’s ecosystem
Soil formation begins when parent material is exposed to the effects of the atmosphere, hydrosphere, and biosphere Parent material can be lava, volcanic ash, rock, dunes or most commonly, bedrock Bedrock is the continuous mass of solid rock comprising the Earth’s crust
Weathering = the physical, chemical, or biological processes that break down rocks to form soil Physical (mechanical) = wind and rain, no chemical changes in the parent material Chemical = substances chemically interact with parent material Biological = organisms break down parent material
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