METAIS PESADOS EM SOLO TRATADO COM LODO DE ESGOTO E CULTIVADO COM CANA-DE-AÇÚCAR

Abstract

The sewage sludge is a residue from waste water treatment municipal plants. Because is generated in large amounts, it is a constant preoccupation in relation to environmental contamination. So, sewage sludge agricultural reuse is one technical alternative to environment deposition. The objective of this research was evaluate the effects of sewage sludge increasing rates incorporated in the soil, on phytoavailable Cr, Ni, Pb and Zn soil contents, after sugarcane crop. The experiment was conducted out in a field conditions, at Guariba County, São Paulo state, Brazil. The soil was a Red Argisol, middle texture. The experimental design was a randomized blocks with three replications, in 4x2 factorial scheme plus an additional control treatment. The treatments were resulted from combination between four sewage sludge rates (0, 10, 20 and 40 t ha-1, dry base) and two mineral fertilization levels (50 and 100% of the recommended rate to sugarcane). The control treatment was a soil in it natural conditions. Soil samples were collected in plant lines and between lines and analyzed to heavy metal contents. No differences were observed between the treatments of the factorial scheme and the control treatment. Sewage sludge increasing rates, in general, increased Cr, Ni Pb and Zn soil contents when the samples were from plant-line and between-line. The sewage sludge applied at 40 t ha-1 promoted the largest contents of heavy metals in the soil.

Keywords

• Saccharum spp.
• Biosolid
• Trace elements
• Urban residues recycling