EESC1180 Lecture Notes - Lecture 7: Entisol, Volcanic Ash, Andisol
26 Sep 2017
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Document Summary
Downward percolating water transports ions and clay. Hardness of rock determines amount and thickness of soil. Exposed rock from steep drop typically doesn"t have soil. Older soil is thicker than younger soil. Older thicker soil is on old rock, younger lava flow cools over it and. Soil classification -u. s. comprehensive soil classification younger soil forms on top of the new rock. Grey brown, subsurface clay accumulation and abundant plant nutrients, forms in humid forests. Low in organic matter, carbonate horizons, arid environments. Very rich in organic debris forms in swamps and marshes. Very weathered, rich in aluminum oxide and iron oxide, low in plant nutrients. Acidic, low in plant nutrients, ashy, accumulations of iron and aluminum, forms in humid forests. Very mature, strongly weathered soils, low in plant nutrients. Clay-rich soils capable of swelling when wet and then shrinking and cracking when dry. Hummus on top iron oxide and aluminum oxide accumulate, calcite is leached.
