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

✍ Scribed by Laura A. de Oro; Daniel E. Buschiazzo

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 238 KB
• Volume: 20
• Category: Article
• ISSN: 1085-3278
• DOI: 10.1002/ldr.863

✦ Synopsis

Wind erosion starts when the threshold wind velocity (m t ) is exceeded. We evaluated the sensitivity of m t to determine the wind erosion susceptibility of soils under variable climatic conditions. Three years field data were used to calculate m t by means of the equation m t ¼ u ¯-s F À1 (g), where u ¯is the mean wind speed (m s À1 ), s the u ¯standard deviation (m s À1 ), g the saltation activity and F the standard normal distribution function of g. Saltation activity was measured with a piezoelectric sensor (Sensit). Results showed that u ¯of the whole studied period (3Á41 m s À1 ) was lower than m t (7Á53 m s À1 ), therefore, wind erosion was produced mainly by wind gusts. The m t values ordered in the sequence: Winter (6Á10 m s À1 ) < Spring (8Á22 m s À1 ) ¼ Summer (8Á28 m s À1 ) < Autumn (26Á48 m s À1 ). Higher m t values were related to higher air humidity and lower wind speeds and temperatures. The m t values did not agree with the erosion amounts of each season, which ordered as follows: Summer (12Á88 t ha À1 ) > Spring (3Á11 t ha À1 ) ¼ Winter (0Á17 t ha À1 ) ¼ Autumn (no erosion). Low m t and erosion amounts of Winter were produced by a scarce number of gusts during eroding storms. We concluded that m t is useful as an index of soil susceptibility to wind erosion of different climatic periods. The use of a unique m t value in wind erosion prediction models can lead to erroneous wind erosion calculations.