Abstract: A field experiment was carried out,using a compound of coal gangue,fly ash sludge as substrate for planting ryegrass.Soil enzyme activity and microbial functional diversity at different stages of reclamation were analyzed,so as to explore feasibility of fertilize-free soil reclamation in mining area.Results show that soil enzyme activity and microbial functional diversity increased after the reclamation.Total nitrogen,available phosphorus and available potassium decreased by 72.05%,67.86% and 60.19%,respectively,and activities of saccharase,dehydrogenase,urease and alkaline phosphatase increased by 130%-756% after 23 months of reclamation.Results of the Biolog Eco plate indicated that 16 months and 23 months after reclamation,average well colour development(AWCD)of microbial population,Shonnon diversity,Simpson index and Mclntosh index were all significantly higher than those before reclamation(P<0.05).The indices were positively related to soil enzyme activity and soil organic matter(P<0.05 or P<0.01),and negatively to total nitrogen,available phosphorus and available potassium(P<0.05 or P<0.01).Sludge could be added as an organic amendment in soil reclamation in the mining area,which contributes to the improvement of plant growth and microbial activity.

Key words: reclaimed soil in mining area, Biolog, microbial community functional diversity, enzyme activity