Impact of biochar amendment on enzymatic resilience properties of mine spoils

Soil enzymes are crucial for soil nutrient cycling function. Understanding of the factors that control their response to major disturbances such as dumping of environmentally toxic acidic waste remains limited. We evaluated the effect of dumping of overburden (OB) and their amendments using biochar, on the resistance and resilience of soil enzyme activities involved in phosphorus, nitrogen, sulphur and carbon cycling (acid & alkaline phosphatase, urease, arylsulphatase, dehydrogenase, phenol oxidases, cellulase and beta-glucosidase). For investigation the soils treated with OB and with the mixture of OB and biochar were used for the cultivation of bacopa were used. We assessed 0 day, 45 day and 90 days activities of the target soil enzymes, available phosphorus, nitrogen, sulphur, soil organic carbon and microbial identification. The resilience and resistance index of all the treatments were calculated. We found that phyto-remediated OB-contaminated soil has its own resilience power. However, biochar addition enhanced the enzyme resistance and resilience of OB contaminated soil. In silico study indicates that biochar-Fe complex play a significant role in enzymatic activities. Overall, the results indicate a significant influence of phytoremediation and biochar addition on soil enzymatic activity that is extremely resistant to OB. This study provides insight on how biochar addition modulates soil biochemical and microbiological response to OB affected soils. (C) 2015 Elsevier B.V. All rights reserved.