Impact of tillage and residue management on the soil properties and water erosion of a Mediterranean Vertisol

Moussadek, R., Mrabet, R., Zante, P., Lamachere, J. M., Pepin, Y., Le Bissonnais, Y., Ye, L., Verdoodt, A. and Van Ranst, E. 2011. Impact of tillage and residue management on the soil properties and water erosion of a Mediterranean Vertisol. Can. J. Soil Sci. 91: 627-635. Soil erosion research on Mediterranean Vertisols under no tillage systems (NT) is still scarce. A rainfall simulator was used on Vertisols to compare water runoff and soil loss in a conventional tillage system (CT), NT system with crop residues removed (NT0), and NT with 50% of crop residues returned to the soil surface (NT50). Runoff and soil loss rates were more than 50% lower under NT50 compared with NT0 and CT. Wet aggregate stability (MWD), soil organic matter (SOM) and soil bulk density (Da) were significantly higher under NT than under CT. A multiple regression analysis showed that when the soil was dry, Da explained 84 and 96% of the variation in water runoff and soil loss, respectively. Under wet soil conditions, MWD explained 47 and 69% of variation in water runoff and soil loss, respectively. Consequently, although NT systems improved soil quality (MWD, SOM) compared with the CT system, returning 50% of crop residues at the soil surface was mandatory under NT to protect these Vertisols against water erosion.