Sugarcane Yield and Heavy Metal Availability in Two Biosolid-Amended Oxisols

Abstract

Although the agricultural use of biosolid has been recommended, there is little information on its agronomic results and environmental impacts under tropical conditions. A pot experiment was carried out using two Brazilian Oxisols amended with one limed-digested biosolid and cultivated with sugarcane. The biosolid application lowered the purity and sucrose level of the sugarcane juice and increased its reducing sugar concentration. However, the stalks production was increased by 35% in the clayey soil and by 72% in the less clayey soil due to biosolid amendment, with overall increase of 45% sugar for the latter soil. Biosolid application increased the leaf concentrations of chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn), only for the less clayey soil, with Cr being statistically significant. Cadmium was not detected in the sugarcane leaves and juice as well as Ni in the sugarcane juice. Sequential extractions showed that the metals absorbed by plants in the amended soils were released mainly from the carbonate and organic fractions. Results suggested that the biosolid nitrogen (N) concentration is main aspect that must be considered for optimizing the effects of the biosolid application on the sugarcane yield in Oxisols.