The use of cover crops is a strategy to maintain the productive capacity of agricultural soils. The increase of organic carbon content, nutrient cycling and, consequently, the increase in soil fertility are some of the greatest benefits. This study evaluated the chemical attributes of the soil after the use of cover crops species in the Cerrado region of Piaui. The experiment was carried out from January 2015 to July 2016. It was performed in a completely randomized block design with eleven treatments and four replicates. ), potential acidity (H + Al), soil organic carbon (OC), the saturation of bases (V%), saturation by aluminum (m%) and effective CEC were measured. Fifteen months after their establishment, cover crops positively influenced the levels of P, K and OC with no changes in the other chemical properties. The OC contents were higher with the use of C. cajan -cv. 'fava larga', brachiaria and C. ochroleuca + millet, mainly in the topsoil. C. espectabilis, spontaneous vegetation, M. aterrima, brachiaria and C. ochroleuca were the most efficient in K cycling.