The agricultural use of urban waste compost (WC) is an alternative for a better environmental-economic viability, because this organic residue is a source of nutrients and organic matter. This study was carried out in a greenhouse at the Brazilian Agricultural Research Corporation/National Soil Research Center. It had the objective of evaluating the effect of WC doses (0; 25; 50 and 100 Mg ha-1) and incubation periods (16; 32; 64 and 150 days) on micronutrients availability Cu, Fe, Mn and Zn by Mehlich-1, in Rio de Janeiro and Sao Paulo soils (Red-yellow Latosol, Red-yellow Podzol, Chernossolo Haplico Órtico, Planosol and Red Dusky Podzol). Most of the micronutrients had their availability reduced at the beginning of incubation, which was dependent of the texture, pH and organic matter content in the soil. Continued use of WC, mainly in the highest doses, and especially for the Mn and Zn, can result in risks of soil contamination, in periods more than 6 months with reduction of availability of the elements.
urban solid residue; organic matter; heavy metals
