The application of biochar as a soil amendment in land reclamation

Abstract

Surface mining activities cause severe adverse effects on soils. Scientists across the world have used different physical, chemical and biological reclamation techniques to recover mining disturbed areas. The effectiveness and efficiency of reclamation techniques is crucial to reclamation success. Biochars are biological residues combusted under low oxygen conditions, resulting in a porous, low density carbon rich material. Research has suggested that biochar can be used as an amendment to improve soil physical, chemical, and biological quality. The present study investigated the application of biochar as a soil amendment for land reclamation. Specifically, the impact of biochar application on aspen growth, microbial biomass, soil respiration, heavy metal adsorption, and metabolic quotient were measured in a greenhouse experiment using land reclamation soils and in a field experiment on a reclaimed coal mine west of Edmonton, AB, Canada. Results of the greenhouse experiment showed that the biochar had the ability to retain the soil nutrients, increase the soil microbial biomass and soil heterotrophic respiration; while the petroleum- coke had a negative impact on tree growth. In the field experiment, the results showed that biochar increased DOC, DON (dissolved organic carbon and nitrogen), MBC and MBN (microbial biomass carbon and nitrogen) and soil heterotrophic respiration. The results are consistent with previous findings which suggested that biochar can improve soil available nutrient and increase microbial activity.