Abstract:

 Biochar-amended soil is under investigation as an approach to carbon sequestration to produce and improve soil fertility and increase agricultural productivity and quality. Previous studies showed absorptive effects of biochar on heavy metals including Cu, Cd, etc. However, Cr(Ⅵ) has got few attention to study in biocharamended soil. Herein, soil column leaching experiments are designed for Cr(Ⅵ) migration behaviors in soils before and after adding biochar. In particular, simulated acid rain leaching is for understanding the locking effect of Cr(Ⅵ) in biochar/soil. The results showed that 1% of biochar added in soil can fix much more Cr(Ⅵ). Furthermore, small particles of biochar showed a stronger adsorption capacity and they could lock Cr(Ⅵ) as three times as large particles, while Cr(Ⅵ) was not easy to release again under acid rain leaching. It confirms that biochar effectively mitigate Cr(Ⅵ) migration in soils and it has locking effect on Cr(Ⅵ), which provides an important means and basis for development of farmland soils.

Key words: biochar, Cr(Ⅵ), soil column leaching experiment, migration, simulated acid rain