Physicochemical characterizations of three types of soils of Sais,Morocco [Caractérisations physicochimiques de trios typesde sols du Sais,Maroc]

The study area is part of sais,which is a very wide range of plains and plateaus of central northern morocco. the majority of soils derived from sais lacustrine limestones and called tawny sands. these are based on tortonian marls intercalated with sandstone and conglomerates. the physico-chemical characterization of three classes of soil representing the saïs region (two depths: 0-30 cm and 30-60 cm) has highlighted the dominance of the clay fraction in vertisols and calcimagnesic soils while it is the sands that dominate in the fersialitic soils. in the three soil classes mentioned above,the organic matter is present in low concentrations. the cation exchange capacity is closely linked to the mineral fraction and in the clays that determine the amount of exchangeable bases in soils. the average ph value (7.62) is the three soil types from neutral to slightly basic soils. the calcimagnesic soils show high levels of total limestone compared to vertisols and fersialitic soils. for the majority of soils studied,the levels of nitrates and phosphates are relatively important on the surface more than in the depth.