GEOG M107 Study Guide - Midterm Guide: Tillage, Soil Structure, Silt
Document Summary
Great plains states: what are the three different ways in which wind carries soil, suspension: soil particles and aggregates less than 0. 05mm in diameter (silt size and smaller) are kept suspended by the turbulence of air currents. Suspended particles do not drop out of the air in quantity unless rain washes it out or the velocity of wind is reduced: saltation: intermediate-sized grains (0. 05mm to 0. 5mm in diameter) move in a series of short leaps. Jumping grains: gain energy and knock other grains into air or bounce back themselves. Key to wind erosion: drastically increase number of both smaller and larger grains that move in suspension and in surface creep, surface creep: soil grains larger than 0. 5mm in diameter cannot be lifted into the wind stream. Surface roughness absorbs drag, reducing energy used to erode: vegetation slows wind velocity, wind strong enough to cause erosion is turbulent. Increased turbulence, increased friction velocity, increased surface roughness, changes in surface temperature.
