Soil Aggregate Abrasion by Impacting Sand and Soil Particles

Abstract

ABSTRACT DURING wind erosion, erodible particles (< 0.85 mm diameter) are removed continually in saltation and suspension, but the supply of particles is rarely exhausted because new erodible-size particles are created constantly by abrasion. Little is known about the physics of soil abrasion, however. This study was undertaken to determine the effects of particle speed, size, impact angle, and stability on the abrasive erosion (W) of soil aggregates of various stabilities. A calibrated sandblasting device was used to abrade individual aggregates with weighed amounts of abrader in an enclosed chamber and the weight of soil abraded from the aggregates was determined. Regression equations relating aggregate abrasion to the experimental variables were then developed. Sand abrader produced higher values of W than soil abrader. W also increased as a power of particle velocity. The power was near 2.0 for fragile aggregates and ranged from 1.5 to 2.3 for the most stable aggregates tested. The W of all aggregates decreased nonlinearly as aggregate stability increased. The largest W occurred at impact angles of 20 to 30 deg, and a small increase in W occurred as average particle diameter increased from 125 to 715 /um..