## 1 Introduction  
Mining can transform fertile, cultivated land into unfertile land. One way is by altering the structural and function of the soil microbial community [1; 2]. Remediation of mine wastlands is one of the pressing needs to be addressed for social and economic development to be healthy and sustainable. The ultimate goal of mine land remediation is therefore the re-establishment of a productive, healthy and sustainable ecosystem for post-mining land use [3]. Currently, criteria for successful remediation have paid much attention to soil erosion, physico-chemical properties of the substrate and vegetation characteristics [4; 5]. It should be noted, however, that soil microbial community is of critical importance for the ecological functioning of an ecosystem such as nutrient cycling, plant establishment, geochemical transformations, and soil formation. In this sense, soil microbial community properties should be considered also as important criteria for evaluating the success of remediation schemes for mine sites [6]. Therefore, more emphasis must be given to understanding the roles of the mine soil microbiota for developing sustainable remediation [7; 8; 9]. Soil enzymes are associated with the proliferation of soil microbial communities. Their activities integrate information about microbial status and soil physico-chemical conditions and are indicators of the functioning of soil ecosystems [6]. Soil enzyme activities have similarly been used in studies on the effectiveness of remedial treatments on soil quality. Dehydrogenase is an oxido-reductase enzyme which has been used as a measure of overall microbial activity [10]. Cellulase, urease and phosphatase, related to the cycles of C, N and P, are sensitive indicators of management-induced changes due to their strong relationships with soil quality [11; 12]. Dehydrogenase, cellulase, urease and phosphatase activities have all been reported as indicators of progress in soil-remediation processes of mine soils [13; 14]. In addition, the activity of acid phosphatases may be a useful bioindicator for monitoring the soil quality of acidic, P-deficient substrates [15]. To date, several researches have shown that the addition of inorganic and organic materials either stimulated soil microbial activity, or increased soil microbial diversity, microbial biomass, enzyme activity and nutrient status [7]. However, previous studies have rarely explored the effects of amendments on these microbe-related parameters simultaneously, representing a knowledge gap in the field. Sulphidic mine soils represent a typical anthropogenic extreme environment, as indicated by the much lower diversity of dwelling microbial communities relative to natural soils [16]. Dabaoshan pyrite/copper mine is a representative polymetallic mine located in Guangdong Province, southern China. Mining activities here have generated large quantities of pyrite-rich deposits discarded on the mine site. Metal sulphides in the mine soil have undergone oxidation and hydrolysis and generated large quantities of acidity which resulted in the pH of the mine soil lowered rapidly and metal ions released at extremely phytotoxic levels [17]. Acidification and heavy metal toxicity act synergistically under natural conditions, which collectively can degrade the biological properties of mine soils including nutrient depletion and changes in the microbial community [18]. Traditionally, remediation studies on acidic, metal-contaminated mine wastelands have focused on the determination of changes in the extent of acidification and the available heavy metal pool [17]. However, the effectiveness of remedial practices on the soil microbial community and nutrient element bioavailability is generally limited. Further studies are therefore needed to determine the potential of any improved remediation strategy for the restoration of soil microbial properties and nutrient status enhancement.