In Morocco, water scarcity is a major factor limiting agricultural production. Water shortage is accentuated by soil quality depletion exaggerated by intensive cropping and tillage systems that cause a decline in soil fertility, structure and organic mater. No-tillage system (NT) has been proposed as a viable alternative to conventional tillage (CT) to improve the soil quality and ensure water conservation. The aim of the present study was to evaluate tillage effects on soil moisture, soil organic matter (SOM) and soil aggregate stability in a Calcixeroll soil under three tillage treatments: conventional tillage system (CT), NT system with crop residues removed (NT0), and NT with 50% of crop residues returned to the soil surface (NT 50). Our results showed that residue cover combined with no-tillage (NT 50) has significantly increased the levels of SOM at the top 100 mm soil layer compared to CT and NT0. The results also indicate that soil water content in the three studied layers (0-50, 50-100 and 100-300 mm) was higher for NT. The performance of soil aggregates was better with regard to the different stresses caused by the mechanical tests. This usually leads toward soil consolidation and increasing the soil resistance to wind and water erosion. We conclude that the increased yield associated with no-tillage system can be explained by both better water conservation and soil quality improvement.

Soil degradation is becoming the major problem of Moroccan soils in semiarid areas. This deterioration is due to poor soil management through recurring tillage practices that cause a decline in soil organic matter and degradation of their structural state. This study aims to characterize the impact of tillage, residue management and cropping systems on the aggregate stability and the accumulation of organic matter in a Calcixeroll soil. Three tillage treatments were compared: conventional off-set disking, no-tillage system with two levels of residue: NT100 = full surface residue cover and NT50 = half surface residue cover, along with three rotations: continuous wheat, fallow