The effect of biochar mixed with compost on heavy metal concentrations in a greenhouse experiment and on Folsomia candida and Eisenia andrei in laboratory conditions

Abstract

Organic wastes treated, used on agricultural land, can replace inorganic fertilizers, due to physical and chemical properties that improve soil and crop quality on long-term. In this study, was used biochar produced from sewage sludge, compost obtained from cattle manure, and mixtures made from biochar-compost in different concentration, at 5 t/ha and 30 t/ha, application rates. The aim of the study is to determine the influence of this organic wastes on the heavy metals bioavailability in greenhouse conditions and on Folsomia candida and Eisenia Andrei, used as test organisms under laboratory conditions. Compared to control variants, the use of biochar mixed with compost in different concentration at 5 t/ha and 30 t/ha, application rates, in a greenhouse experiment did not significantly affect the concentrations of heavy metals (Cu, Cd, Zn and Pb). Reproduction of collembolans has not been influenced by increasing application rate of the mixtures, and by concentrations of biochar or compost. The earthworms recorded weight losses, only in the experimental treatments with sewage sludge biochar used in different concentrations, at both application rates.