Soil tillage and wind erosion in fallow lands of Central Aragon, Spain:: An overview

In semiarid Central Aragon (NE Spain), fallow lands are prone to wind erosion due to strong and dry WNW winds (Cierzo), insufficient crop residues on the surface, and multiple tillage operations during the fallow period (16-17 months). We review the main results of studies on the effects of tillage on soil surface properties affecting wind erosion in the region. Compared to conventional tillage, reduced tillage (chiselling) provides higher soil protection against wind erosion through a lower wind-erodible fraction (EF), a higher percentage of soil cover by crop residues and clods, and a higher roughness. Soil texture and tillage systems are the main factors affecting soil erodibility. Predicted wind erosion during the most critical period of fallow (February-April), using the Wind Erosion Equation (WEQ), is high to very high (> 20 Mg ha(-1)) in 30% of fallow fields. Adoption of chisel ploughing, as a primary fallow tillage operation, can be an effective strategy for wind erosion control. The need for direct soil conservation measures and recommendations to prevent wind erosion for Central Aragon are also discussed.