Abstract: The interface region steppe-Saharan, where the study was conducted is pastoral where the main activity is sheep production. The strong anthropological pressure has resulted in a reduction of the plant’s potential, inducing a fragile ecosystem promoting more increased desertification. This work was undertaken in six stations distributed along a north-south transect. The physicochemical analyzes of these stations indicated a skeletal nature of the soil, sandy and limestone with CaCO3 amount greater than 20, a pH ranging from 8.10-8.70 and a water retention capacity between 17.40-36%. The analyzes have also shown that the studied soils are rich in organic matter with a ratio greater than 4%, with a C/N ratio lower than 12. As for microbiological analyzes, they showed a bacterial presence varies that greatly from one station to another predominantly of Pseudomonas sp., Staphylococcus sp., Clostridium sulphite-reducing, Enterobacteria and Streptococci sp.