Urbanization in Africa is increasing exponentially.The major factors responsible are the consequences of desertification.In the absence of a well established urbanization plan or by disregarding existing plans,the occupation of limited land around growing cities is under constant pressure.This development creates "soils dominated or strongly influenced by human-made material" (WRB),the newly in the WRB-system introduced "Technosols".In addition,the influx of rural population with their local customs of land occupation and land management,causes the use of alternative fertilization practices in the developing urban and periurban agriculture.Locally available materials such as sewage waste,household refuse and lime from urban rubble significantly affects and alters the soils in and around African cities.Some studies link issues of public health like the recent Abidjan disaster to the contamination of food or water by Technosols.It is proposed to respect soil quality for urban planning.This,to direct urbanization in Africa more to the preservation and development of life worth,healthy and sustainable cities.This study focuses on Dakar,the Senegalese capital.Dakar represents Sahelian African cities that are special cases as their demography is dominated by rural population that recently migrated into the city.