Mineralization and effects of poultry litter biochar on soil cation exchange capacity

Abstract

The objective of this work was to characterize carbon mineralization process in poultry litter samples and in its biochar, as well as to determine the soil cation exchange capacity (CEC) and the C mineralization rates in soils treated with poultry litter and biochar. Carbon mineralization was evaluated through the quantification of released C‑CO₂ from mixtures of soil and poultry litter and of soil and biochar at doses equivalent to 0, 1,000, 2,000, 4,000, and 8,000 mg kg^-1 C, in a 64‑day incubation experiment. At the end of the incubation period, carbon content, pH, and CEC were determined in soil samples. Carbon mineralization of the materials fitted to first order kinetics equation. Fluxes of C‑CO₂ were more intense from 20 to 40 days of incubation, followed by flux decreases until their stabilization. Carbon mineralization rates of poultry litter and its biochar were respectively 49.7 and 5.1%. Increases of CEC were observed in the biochar treatments, as a consequence of pH rising, and in both materials due to soil‑carbon content alterations.