A study in incubation (3, 7, 14, 30, and 60 days) was carried out in a Dusky Red Latosol in order to evaluate the effects of stillage, filter cake, and boiler ash for some chemical characteristics of that soil. All residues were used as potassium source and it was applied at the rate of 300 and 750kg/ha of K. After 60 days of incubation electrical conductivity and pH of all treatments showed to be higher than the control. The nitrate content decreased with time for the dry stillage, filter cake and boiler ash and H2SO4 0.05N soluble in the last two treatments. Practically all applied K, Ca and Mg, were recovered in the HNO3 0.05N soluble form, with the exception of K from boiler ash (50%) and Ca and Mg from the filter cake (57 and 64% respectively).