BIOL 1202 Study Guide - Midterm Guide: Soil Texture, Silt, Ion
Document Summary
Concept 37. 1: soil is a living, finite resource: define soil texture and soil composition, soil texture depends on the size of its particles. Can range from coarse sand, to silt, to microscopic clay particles: soil composition encompasses its inorganic (mineral) and organic components. Organic components include the many life-forms that inhabit the soil: explain how soil is formed, arises from the weathering of rock, water freezing in the crevices of rocks causes mechanical fracturing. Weak acids in the soil break down the rocks chemically: mineral particles released by weathering become mixed with organisms and humus. Forms topsoil: name the components of topsoil, inorganic components. Positively charged ions: k+, ca2+, mg2, organic components. Humus: the remains of dead organisms and other organic matter. Clays are best at holding onto nutrients: define cation exchange, explain why it is necessary for plant nutrition, and describe how plants stimulate the process, cation exchange.
