The sugarcane industry in Brazil produce large amounts of organic wastes including vinasse and filter cake which have been applied to agricultural soil in appreciable amounts over the past two decades. This study examines the chemical characteristics of vinasse and filter cake and their interaction with soil particles. The total concentration of heavy metals found in these residues were relatively small and considered environmentally safe for land application. About 22-100% of the total concentration of Cu, Fe, Mn, Ni, Pb and Zn in vinasse are in water soluble forms compared to only 0.3-17% in filter cake. Elevated amounts of sulfate, chloride and dissolved organic carbon (DOC) were found in the <0.22-[mu]m fraction of vinasse. Filter cake samples had high amounts of phosphate and neutral pH. Most of the 13C NMR spectra of the DOC fraction of vinasse comprised of O-alkyl and carboxyl carbons. The presence of carbohydrates and COOH/COO- was suggested by the FTIR as well. Both 13C NMR and FTIR spectra of this fraction were generally similar to the spectra of the FA fraction of soil and sewage sludge. In the POC fraction, O-alkyl and alkyl carbon were the major contributors to the 13C NMR spectra. The total nitrogen content in this fraction ranged from 21-58 g kg-1 and was about three to seven times as much as in the DOC fraction. Adsorption isotherms of DOC from vinasse on different horizons of an Ultisol indicated that DOC adsorption increased with depth. Adsorption isotherms of DOC on pure kaolinite, synthetic goethite and hematite showed that the maximum adsorption capacity of the Fe-oxyhydroxides was as much as about five times the maximum adsorption capacity of kaolinite. Concentrations of Cu, Mn, and Zn in 4M HNO3 and AAAc-EDTA extracts were higher in the "sacrificed areas" compared to the other sites. Levels of Pb were unchanged. Enrichment of most of these metals was evident up to the maximum depth of 60 cm. Sugarcane cultivation tended to reduce total carbon at the 0-20 cm depth while application of vinasse did not influence the organic matter content of these soils.