ENVIRSC 2B03 Lecture Notes - Lecture 1: Soil Horizon, Geochemistry, Dynamic Equilibrium
7 Feb 2017
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Document Summary
Soils are primarily in the unsaturated level of the hydrologic cycle. Organic soils form in the low-lying areas of the earth"s surface, where water collects. Water is the primary way that things move around in the soil. Soil supports almost all terrestrial life plant roots grab nutrients and water from the soil. In dry areas, roots are widely distributed and close to the surface of the soil so that water can be more easily absorbed. Diffusion acts quickly from soil into roots. 50% is pore space: water and air that changes composition over time because of living things in the soil. 50% is solids: minerals that break down and erode away, and organic matter. Different soils hold different amounts of water. Ex: clay (fine soil) holds water much better than coarse sand. Because of respiration, there is more carbon dioxide in the soil than anything else. Microbes are the highest contributors to respiration in the soil.
