Volume 5 Article informations The impact of the slope on the organic and minerals amendments in the salinity of soil in the south Tunisian Souad Maatoug a,* , Abdessatar Hatira a , Nissaf Karbout b , Mohamed Ouaja c , Mohamed Moussa b , Abdelmajid Kadri b Abstract In the arid regions of southern Tunisia, the date palm is the main source of income for farmers. However, soil degradation through salinization has a significant influence on soil fertility in this Oasis system. Thus, in order to mitigate the consequences of soil degradation in the old oases and to find solutions to this problem, we will consider the amendment as an effective action for degraded soils restoration and a means for improving the production and preservation of agricultural activity. In effect, this study analyzes the potential effects of mixed organic-mineral amendments on the evolution of marginal soil salinity properties along a downstream upstream transect that ends in the natural outfall (Chott) of surface water and irrigation. Two amended plots since two years have been selected in Om Rouss oasis in southwestern Tunisia: (i) Soil upstream at high slop with an area of 8 hectares; (ii) Soil downstream at low slop with an area of 7 hectares in comparison with (iii) no amended control soil. The physicochemical characterization of these soils revealed that their functional properties materialized mainly by particle size, salinity are closely related to the topographic position, the overall texture and closeness to the Chott. Upstream sandy-loam soil characterized by a good infiltration was slightly desalinized and leached soluble salts in the lower levels while the heavily impacted area was scattered sporadically in the downstream zone. Key words: Amendments, Salinity, High/Low slop, Soil texture, Tunisia