赤泥改良过程中微生物群落及酶活性恢复研究

Resilience of soil microbiome and enzyme activity with soil amelioration of Bayer process red mud

本研究选用蛭石、粉煤灰为基质改良剂,以园林落叶为改良基质的有机质来源,通过长期取样分析培养基质pH值、EC、CEC等基本理化指标、氮素(NO_(3)^(-)-N)含量以及微生物群落功能多样性、群落结构、酶活性等微生物指标的动态变化,来评估赤泥生态修复效果.结果表明,赤泥基质改良处理能显著降低赤泥比重,增加其孔隙率;经近1a的室外培育,基质的pH值、EC分别由11.25和1.05mS/cm降至8.49和0.27mS/cm,硝态氮含量也由8.72mg/kg增至72.17mg/kg;相应的脱氢酶、脲酶及碱性磷酸酶活性也日趋接近对照土壤,微生物群落多样性逐渐增加,群落结构显著变化,其整体代谢功能逐渐恢复.综合比较各处理的修复效果,可知在相同有机质添加量下,粉煤灰添加的处理效果优于蛭石添加,可加速赤泥的土壤化进程,为赤泥土壤化修复和规模化处理研究提供科学依据.

Soil treatment is the key to the scale harmless disposal and ecological restoration of red mud.In this study,vermiculite and fly ash were used as matrix improvers,and garden leaves were used as the source of organic matter.To evaluate the ecological restoration of the treated red mud,the physical and chemical indexes(such as pH,EC,CEC,the content of nitrogen(NO_(3)^(-)-N))and the dynamic changes of microbial indexes such as microbial community functional diversity,community structure,enzyme activity,etc.,were analyzed regularly over a year outdoor incubation.The results showed that amendment of both vermiculite and fly ash could significantly reduce the specific gravity of red mud matrix and increase its porosity.After a near year of outdoor incubation,the pH and EC of the red mud matrix decreased from 11.25 and 1.05 mS/cm to 8.49 and 0.27 mS/cm,respectively,and the NO_(3)^(-)-N content increased from 8.72mg/kg to 72.17mg/kg.The corresponding activities of dehydrogenase,urease and alkaline phosphatase were gradually approaching to the reference soil.The diversity of microbial community increased gradually,the community structure changed significantly,and then followed by the recovery of microbial metabolic function gradually.By the comprehensive comparison on the restoration effect of each treatment,it showed that under the same amount of organic matter,the treatment effect of fly ash addition was better than that of vermiculite addition,which can accelerate the process of red mud soil,and provide scientific basis for the study of red soil remediation and large-scale treatment.