The conservation agriculture in northwest of Morocco (Merchouch area): The impact of no-till systems on physical properties of soils in semi-arid climate

Abstract

Conservation agriculture (CA) is characterized by three principles: minimum tillage, even the total absence of tillage in the case of direct seeding (NT), permanent soil cover by mulch, and diversification of crops. Its main objective is to control soil degradation by conserving the physical and biological properties and fertility of the soil, which leads to an improvement in productivity, while preserving the environment. Conventional tillage (CT) used in the arid and semi-arid environments of Morocco (particularly in the study site area of Merchouch) compromise the productivity of established crops in these regions. The work presented consists in the study of the impact of NT on the physico-chemical properties of the soil, especially organic matter (SOM), bulk density (BD), soil moisture (θg), and structural stability (SS) in semi-arid zones. The results show that the use of the NT system positively influences the accumulation of SOM, especially at the soil surface horizon (0-5cm). Concerning θg, there is a significant difference between the two treatments (NT and CT) at the average of the three depths and especially at the horizon 20-40 cm so NT increases the water retention capacity. This study also shows that the mean weight diameter (MWD) of the 3 tests (water, ethanol, and rehumectation) is higher for NT compared to CT. This shows that no-till helped to build a good soil structure over time, which is highly desirable for improving agricultural productivity and conserving natural resources, especially water.