Solos de tabuleiros costeiros sob florestas naturais e sob cultivo

Landscapes formed on Barreiras Formation sediments occupy significant area on Brazilian territory. Many of these landscapes have highly intensive agricultural use, due to favorable climate and topography. The objective of this study was to characterize and to compare soil profiles situated on non-dissected coastal plains from southern Bahia to Alagoas, occurring under natural vegetation (forest) and agricultural use. Seven soil profiles were analyzed and data from six soil profiles obtained in other works were incorporated. Particle size distribution, organic C (OC), Al, Ca, Mg, Al+H, K, Na, P, Fe, Ti and Si were determined. Clay mineralogy was analyzed by X-ray diffraction. Soil profiles occur on flat relief, have yellow color, weak small to medium subangular blocky structure on B horizon and sub-superficial cohesive character. Texture was the most significant attribute that differentiated soil profiles from each other. All soils have low Fe content. X-ray diffraction results showed kaolinite dominance in the clay fraction. The soil OC was the only attribute tested that significantly varied between the surface materials of forest soils and the cultivated systems (sugarcane, orange, coconut and eucalyptus).