Effect of tillage practices on the hydraulic properties of a loamy soil

Abstract

The knowledge of soil hydraulic properties is essential for modeling the water flow in unsaturated porous media for hydrological applications and agricultural water management. Long-term tillage practices have been shown to affect the hydraulic properties of soil. In this study, a field experiment was conducted to evaluate the effect of roto-tillage and no-tillage practices on the hydraulic properties of a bare loam soil. Two field plots were used with different tillage practices. In the first one, the field has been in roto-tillage for three years and in the other in continuous no-tillage for two years. From the hydraulic properties determined, water retention curves indicated that the water retention capacity was greater in tilled than in no-tilled (NT) soil. Both soil–water diffusivity and hydraulic conductivity values were greater in tilled than in NT soil at relatively low to moderate water contents, and lower in tilled than in NT soil at relatively high water contents—near saturation. The hydraulic properties determined were compared with the predicted ones by the Mualem–van Genuchten (MvG) model. The comparison showed a weakness of MvG model to describe satisfactory the unsaturated hydraulic conductivity with fixed model parameter values.