GEOG M107 Study Guide - Midterm Guide: Aeration, Crop Residue, Clay Minerals
Document Summary
Jury and horton 2004 reading (soil properties: what is soil composed of, composed of solid, liquid, and gas, and diverse community of living organisms. Solid: minerals and organic matter: minerals: quartz, mica. Small relative surface area: only minor influence on chemical and physical properties: how do pores affect soil composition, affect infiltration and permeability; Ex: micropores: water moves slowly: porosity is greater in fine textured soils, however, finer soils have smaller pores. Aggregates high in silt and sand relatively unstable: type of cation on exchange complex: if cation-exchange complex is occupied mainly by h+ or di- or trivalent cations, individual soil particles will aggregate. Increases aggregate stability, reduces water infiltration: cementing agents: secondary lime is a cementing agent, helps hold particles in aggregates. Some iron compounds bind clays and other particles together in stable forms in strongly leached soils: cropping history: soils plowed from native vegetation, cultivated pasture, or meadow resist erosion.
