GEOG M107 Lecture Notes - Lecture 4: Turbulence, Soil Fertility, Soil Structure
Document Summary
Deposition (aka sedimentation- used when human affect) Usually a problem in dry regions, but wind can damage sandy soils in more humid regions, areas without vegetation cover, and when soil is dry. Worst in north america dust bowl in 1930s (most severe wind erosion + severe drought + poor understanding of proper agricultural practices) Prairie states forestry project: established windbreaks and shelterbelts in. Suspension: >0. 05mm kept suspended by air turbulence. Saltation: 0. 05-0. 5mm moving in series of short leaps. Surface creep: >0. 5mm too large to be lifted by wind. >1mm bumped along surface by saltating (the movement of hard particles such as sand over an uneven surface in a turbulent flow of air or water) grains. Larger particles and aggregates: remain in place. Plow layers from recently tilled fields blown away in single dust storms in 1930s. Colloidal clay (round chunks) and organic material most important component of soil fertility. Occurs by crop removal and by oxidation of organic matter.
