Coastal plain soils under natural forests and cultivation

Abstract

Landscapes formed on Barreiras Formation sediments occupy signifi cant 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 profi les situated on non-dissected coastal plains from southern Bahia to Alagoas, occurring under natural vegetation (forest) and agricultural use. Seven soil profi les
were analyzed and data from six soil profi les 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 profi les occur on fl at relief, have yellow color, weak small to medium subangular blocky structure on B horizon and sub-superfi cial cohesive character. Texture was the most signifi cant attribute that
differentiated soil profi les 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 signifi cantly varied between the surface materials of forest soils and the cultivated
systems (sugarcane, orange, coconut and eucalyptus).