IDSB02H3 Lecture Notes - Lecture 3: Soil Texture, Soil Fertility, Weathering
22 Jan 2017
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Idsb02 lecture 3: soils and food security. Soil and trouble show that salinization and desertification are responsible for the loss of land. Soil erosion: 1st wave: civilizations expanding away from alluvial soils into forested slopes. Soil management: rotational crops, shifts and terracing diminish erosion, nutrients, manure, and long fallow periods allow soils to rejuvenate, nitrogen helps to fix plants. Important because soils are diverse globally and highly variable: historical development of soil knowledge classification systems. Soil texture what they are made of rocks get broken down into sand. Sands are susceptible to erosion and clay are not, sand is holding it in place while clay is sticky because of its charge and stays in place. Size and surface area: sand is larger, but the surface area is not. Clay has a lot of sheets exposed to nutrients and water giving it a much larger surface area. Spheroidal (small balls of soil), plate-like (stacked), block-like (chunks) and then prism-like (cone shapes)
