This study was carried out to evaluate the nutrient concentration in seven different organic composts produced with crushed sugarcane, nappier grass, coffee straw and liquid swine manure. Each compost was produced with one or more plant residues, associated to swine manure, whereas the crushed sugarcane was also associated to gypsum and triple superphosphate. A randomized block experimental design was used, with three replicates and seven treatments. After a 120-day period, the samples were collected and chemically analyzed in a plasma spectrophotometer and the macro and micronutrients were quantified. Crushed sugarcane as the only plant residue produced a compost with lower values of K, Mg, B, and pH. The addition of gypsum and triple superphosphate did not improve significantly the quality of the compost produced only with crushed sugarcane and swine manure. The composts produced with coffee straw presented higher K and pH values. Combining crushed sugarcane and coffee straw provided composts with a better quality and may be a promising practice for the 'Zona da Mata' region, Minas Gerais, Brazil, where these residues are easily found. The concentrations of Cu, Fe and Zn in the produced compounds did not exceed the safe limits for use in soil.
composting; swine; manure; vegetal residues; nutrient