TYPOLOGY AND PHYSICOCHEMICAL CHARACTERIZATION OF THE MAIN SOILS OF THE KAWAR OASES (NORTH-EASTERN NIGER)

The Kawar Oasis system constitutes a unique ecosystem located between the Tenere erg and the Bilma erg. The oases mainly occupied by date palms are spread out to the east, along the sandstone cliff, of Tertiary age. They support the economic activities of local populations such as agriculture and artisanal salt exploitation. The aim of the present study is on the one hand to categorize these oases and on the other hand to characterize these soils for better cultural suitability. Twelve villages distributed in the communes of Dirkou, Bilma, Fachi and Djado served as study areas. Focus group surveys made it possible to collect data related to the typology, characterization and agricultural suitability of the soils. The results obtained show that these oases are classified into three categories, namely Spring Water Oases (OES), Relic Fossil Lake Oases (ORLF) and Outcropping and Brackish Water Oases (OEAS). As for the results of the physico-chemical characterization show that the textures of the soils are sandy to sandy-loamy. The pH ranges from alkaline to extremely alkaline, the electrical conductivity is from non-saline to extremely saline. The organic matter content is low to very high. The development of these sites requires the use of crops more tolerant to salinity other than date palms. This study can serve as a basis for decision-makers and operators to have ideas on the vocations of each type of Oasis. It will also enable their cultivation skills to boost agrosylvopastoral production.