Effects of reduced tillage on soil surface properties affecting wind erosion in semiarid fallow lands of Central Aragon

In Central Aragon (NE Spain), where strong and dry winds are frequent all year round, fallow lands are susceptible to wind erosion due to insufficient crop residues on the surface and loose,finely divided soils by multiple tillage operations. Effects of conventional tillage (CT - mouldboard ploughing followed by a compacting roller) and reduced tillage (RT - chisel ploughing) on soil surface properties affecting wind erosion were studied during three experimental campaigns in a dryland field of Central Aragon. RT provided higher soil protection than CT through a lower wind erodible fraction of soil surface (on average, 10% less) and a significantly higher percentage of soil cover with crop residues and clods (30% higher). Random roughness was also higher after RT than after CT (15 vs. 4%). These results indicate that RT can be an effective soil management practice for wind erosion prevention during the fallow period in semiarid Aragon. The study shows, likewise, that significant changes in soil aggregate size distribution associated with wind erosion processes may occur in short periods of time. Thus, temporal variability of soil surface properties, including crust and clods stability, needs to be considered in wind erosion research in agricultural soils. (C) 2000 Elsevier Science B.V. All rights reserved.