WIND EROSION IN LOESS SOILS OF THE SEMIARID ARGENTINIAN PAMPAS

Abstract

This study is the first effort to measure wind erosion in the field in South America. Wind erosion of two bare soils, a loamy sand surface Typic Ustipsamment and a sandy loam surface Entic Haplustoll of the Semiarid Argentinian Pampas, were measured in the field during wind storms that started on June 16 (mean wind speed = 14 km/h; storm duration 103 h) and June 30 (mean wind speed = 21.4 km/h; storm duration 25 h) of 1995. Measurements were made with dust samplers placed at heights of 0.135, 0.54, and 1.47 m within a 1-ha field. Mass flux (amount of eroded material within a given time) was larger in the Ustipsamment soils than in the Haplustoll soils in both storms. A maximum amount of transported dust was found within the limits of the studied field (100 x 100 m 2 ) during the June 16 wind storm and outside the studied field during the June 30 wind storm. This was attributed to the variation in wind direction on June 16. The total amount of material eroded from the field during each storm reached 1.82 mt ha -1 in the Ustipsamment and 0.29 mt ha -1 in the Haplustoll on June 16 and 0.98 mt ha -1 in the Ustipsamment and 0.75 mt ha -1 in the Haplustoll on June 30. Wind velocity was high enough to erode the loosened Ustipsamment but not the better structured Haplustoll on June 16. On June 30, wind velocity was high enough to erode both soils, but a shorter storm duration did not allow the erosion of large amounts of soil.