WIND EROSION LOSSES AS RELATED TO PLANT SILHOUETTE AND SOIL COVER

Wind erosion adversely affects soils, plants, animals, equipment, the environment, and people. Wind erosion can be minimized or prevented by either standing residue or fiat residue cover. Our objective was to d evelop mathematical relationships between these two crop residue prop erties and soil toss ratio (SLR: soil loss from protected soil/soil lo ss from flat, bare soil), for more accurate predictions of wind erosio n son losses. Therefore, from a previously reported wind tunnel study (wind tunnel 1.1. m high, 0.51 m wide, and 5 m long) we took data for velocities ranging from 9.4 to 16.1 m s(-1) and silhouette areas (5) o f upright wood dowels (simulating plant stems) ranging from 31 to 813 cm(2) m(-2) of soil surface (washed sand <0.42 mm) and developed the f ollowing equation for standing residue and SLR(5): SLR(delta) = exp(-2 8.49 x S-0.6413/V-2.423) (r(2) = 0.95), where 5 = stalk height (cm) x stalk diameter (cm) x stalk density (no. m(-2) and V = wind velocity i n m s(-1) at a height of 0.61 m. We combined data from a second previo usly reported wind tunnel (0.9 m high, 0.6 m wide, and 7 m long) study in which the soil had been covered from 0.0 to 80.0% with wood dowels , artificial clods, or cotton (Gossypium hirsutum L.) gin trash with d ata from field studies published by other researchers for various soil types and soil coverages ranging from S to 95% with wheat (Triticum a estivum L.) residue or gravel, and developed the following equation fo r soil cover and SLR(c): SLR(c) = exp(-0.04380 x psc) (r(2) = 0.94), w here pse is the percent of the soil that is covered by nonerodible mat erial (e.g., soil aggregates, rocks, plant material). These equations should be useful to researchers developing and evaluating wind erosion models, prediction systems, and wind erosion control practices.