Wind erosion quantity and quality of an Entic Haplustoll of the semi-arid pampas of Argentina

Wind erosion is said to be an important degradation process of soils, but little is known about the magnitude of this process and its effect on soil nutrient transport in Entic Haplustolls of the semia-arid Pampas of Argentina. The objective of this study was to measure the rate of wind erosion and the concentration of nitrogen and phosphorus in the sediment originating from different tillage systems: conventional tillage (CT), vertical tillage (VT), and no-till (NT), for two different crops of the semi-arid Pampas of Argentina. Measurements of airborne sediment were carried out in an 8 ha field using Big Spring Number Eight (BSNE) samplers, in two periods of 1998 and 1999, after seeding sunflower (Helianthus annus) and rye (Secale cerale). Losses and accumulations of material were detected. Losses varied between 4 and almost 900 kg ha(-1), and accumulations between 3 and 580 kg ha(-1). Wind erosion was higher in 1999 than in 1998 in all tillage systems, due to higher wind speeds and lower plant residue coverage of the first measurement period. In 1999, erosion was lower in plots with higher plant residue coverage (NT against CT), and in 1998 sediment accumulation was observed in these treatments. Nitrogen concentration in the sediment collected at greater heights increased and phosphorus concentration decreased with wind speed. This was due to the accumulation of nitrogen in the coarsest aggregates and of phosphorus in the finer aggregates. The nitrogen enrichment of the sediment varied between 2 and 5, while the phosphorus enrichment varied between 1.5 and 8. The nitrogen enrichment increased and the phosphorus enrichment decreased with wind speed. Lower wind-speed storms will erode relatively more phosphorus than nitrogen. When high wind-speed storms occur, nitrogen becomes more susceptible to erosion. Wind speed is the variable that may regulate the amounts of nutrient loss. (c) 2006 Elsevier Ltd. All rights reserved.