Threshold wind velocity as an index of soil susceptibility to wind erosion under variable climatic conditions

Wind erosion starts when the threshold wind velocity (μ t ) is exceeded. We evaluated the sensitivity of μ t to determine the wind erosion susceptibility of soils under variable climatic conditions. Three years field data were used to calculate μ t by means of the equation μ t = ū - σ Φ -1 (γ), where ū is the mean wind speed (m s -1 ), σ the ū standard deviation (m s -1 ), γ the saltation activity and Φ the standard normal distribution function of γ. Saltation activity was measured with a piezoelectric sensor (Sensit). Results showed that ū of the whole studied period (3.41 ms -1 ) was lower than μ t (7.53 ms -1 ), therefore, wind erosion was produced mainly by wind gusts. The μ t values ordered in the sequence: Winter (6.10 ms -1 ) Spring (3.11 t ha -1 ) = Winter (0.17 t ha -1 ) = Autumn (no erosion). Low μ t and erosion amounts of Winter were produced by a scarce number of gusts during eroding storms. We concluded that μ t is useful as an index of soil susceptibility to wind erosion of different climatic periods. The use of a unique μ t value in wind erosion prediction models can lead to erroneous wind erosion calculations.Fil: de Oro, Laura Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Buschiazzo, Daniel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentin