METALES PESADOS EN MAíZ (Zea mays L.) CULTIVADO EN UN SUELO ENMENDADO CON DIFERENTES DOSIS DE COMPOST DE LODO RESIDUAL

摘要

A 2- year field study was performed to evaluate heavy metals (Cu, Zn, Ni, Cd, Pb and Cr) uptake and their distribution in corn plants (Zea mays L.) grown on a calcareous soil amended with different rates of sewage sludge compost. Residual soil heavy metals effect was also determinated along different depths (0-20, 20-40, 40-60 and 60-80 cm). The values obtained for dry matter and for heavy metal concentrations in the different plant parts, did not show significant differences among treatments. Heavy metals concentrations in plant tissues from the compost amended soil were below the tolerance threshold for livestock. Application of compost did not increase significantly the availability of heavy metals (Diethylenetriaminepentaacetic acid [DTPA]-extractable soil metals) and none of them leached from the surface of the soil to groundwater. The low mobility observed could be due to soil characteristics. There was limited transfer of heavy metals from the soil to the corn plants. A short-term application of compost to a calcareous soil did not cause problems to corn plant growth and quality nor to the environment.