Ongoing soil degradation under cotton is a constant concern for farmers in cotton-growing basins. The aim of the study was to assess soil fertility under cotton in the Ouangolodougou production basin. To do this, soil sampling of the 0-15 cm horizon was carried out in the 15 sections that make up the Ouangolodougou production basin over four (4) successive cropping campaigns from 2017-2018 to 2019-2020. Chemical analyses of soil samples were carried out on the following parameters: exchangeable calcium (Ca2+), exchangeable magnesium (Mg2+), exchangeable potassium (K+) and Ammonical Nirogen N-NH4+. Results indicate that the levels of N-NH4+ and exchangeable bases (Ca2+, Mg2+, K+) are below the average threshold values over the 4 successive tracked campaigns. Also, results demonstrated a sectional basis effect of cotton cultivation on N-NH4+, Ca2+, Mg2+, and K+.