Produção de mamoneira adubada com lodo de esgoto estabilizado por diferentes processos

The sewage sludge may become an economically valued product. But it can be contaminated with heavy metals. The objective of this study was to evaluate soil and plant attributes, the levels of heavy metals in soil and castor bean plant and yield in response to sewage sludge fertilization submitted to different stabilization processes. The experiment was carried out in Cambisol, using the castor bean cultivar BRS Energia, in a randomized complete block design with six treatments and four replications. The treatments were: without fertilization (control), fertilization with solarized sewage sludge, composted sewage sludge, vermicomposted sewage sludge, limed sewage sludge and chemical fertilization recommended for the crop. The data obtained in this study were submitted to the analysis of variance and the means of the treatments compared up to 5% of probability through the test of Scott-Knott. The fertilization with limed sewage sludge promoted increases in the contents of Ca and S in the soil, pH, cation exchange capacity and base saturation, as well as the reduction in the Mg content and potential acidity. Leaf N content was generally higher in sewage sludge and chemical fertilizer treatments than in the non-fertilized treatment. Regardless of the form of stabilization, sewage sludge fertilization generated a castor bean seed yield equivalent to chemical fertilization and higher than that of non-fertilized soil. There was a greater increase in soil Zn levels after fertilization with solarized, composted, and limed sewage sludge compared to fertilization with vermicomposted sewage sludge, chemical, and control. In castor bean leaf, the control and solarized sewage sludge increased the Zn and Cu levels more than composted, vermicomposted, limed sewage sludge, and chemical fertilization. Fertilization with vermicomposted sewage sludge and chemical fertilization led to similar levels of Zn, Cu, Cd, Pb, Ni, and Cr, both in soil and plant.

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico

FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior