Research About Effect Of Co-Tnoculant Of Paenibacillus Mucilaginosus And Rhizobium Meliloti On Reclamation Of Dump In Mining Area

Microbial remediation technology has high-efficiency ecological remediation effects,and has become a research hotspot in the field of mine reclamation.In order to reveal the repair mechanism of dual inoculation of Paenibacillus mucilaginosus and Rhizobium meliloti on dumping sites in mining areas,this paper carried out a pot experiment of alfalfa in the soil of the dump site under different gradient single inoculation dosages of Paenibacillus mucilaginosus and different gradient single inoculation dosages of Rhizobium meliloti firstly.The appropriate single inoculum dosage range for the two inoculants was determined by plant growth indicators and soil quality indicators.On this basis,Paenibacillus mucilaginosus and Rhizobium meliloti with suitable inoculation dosages were combined.Dual-inoculation alfalfa pot experiment was carried out to obtain the best dual-inoculation combination.The plant growth,physiological indicators,soil nutrient content,enzyme activity,microbial biomass,bacteria and fungi diversity and community composition were determined.Through comparative analysis of each index between dual-inoculation and single inoculation treatment,reclamation mechanism of dual inoculation on the soil of the dump in the mining area was revealed,and a new and efficient method and theoretical basis for the ecological restoration of the mining area was provided.The results showed below.(1)In single inoculation treatment,low inoculation amount(0.1%,0.4%)and high inoculation amount(1.5%)of Paenibacillus mucilaginosus(PM)had not obvious reclamation effect on the soil of the dumping site.The medium inoculation amount(0.7%,1.0%)had a significant effect on the soil restoration of the dump site.Low inoculation rate(0.01%,0.05%)and high inoculation rate(1.25%)of Rhizobium meliloti(RM)had also not obvious reclamation effect on the soil of the dumping.Reclamation effect of the medium inoculation rate(0.25%,0.75%)was remarkable.(2)In all dual-inoculation treatments,dual-inoculation?(0.7% PM + 0.25% RM)and ?(1.0% PM + 0.25% RM)treatments could significantly increase the total yield index,nodule amount,and chlorophyll content of alfalfa in the dumping,and significantly increase all available nutrients contents,microbial biomass,respiration intensity and all soil enzyme activities in the soil.Dual-inoculation ?(0.7%PM+0.75%RM)treatment could significantly improve most of the alfalfa yield indexes and some soil enzyme activities in the dumping.Dual-inoculation IV(1.0%PM+0.75%RM)treatment only significantly increased the nodulation of alfalfa,soil available potassium content,microbial biomass,invertase and protease activities.(3)Dual-inoculation of Paenibacillus mucilaginosus and Rhizobium meliloti had an synergy effect on plant height,root length,biomass,nodule number of alfalfa,and soil availalbe nitrogen and available potassium content,soil MBC,respiration intensity,invertase,urease,catalase activity.Dual-inoculation had no synergistic effect on leaf physiological indicators.Dualinoculation treatment significantly improved the diversity index of soil bacteria and fungi.At the phylum level,it had a synergistic effect on abundance increase of bacteria Proteobacteria,Bacteroides,and Bacillus phylum,and on abundance increase of fungi Basidiomycota,Mortierella and Mucor phylum.In summary,single inoculation of Rhizobium meliloti had better effect on land reclamation than single inoculation of Paenibacillus mucilaginosus.Compared with single inoculation,dual-inoculation treatment of 0.7% Paenibacillus mucilaginosus and0.25% Rhizobium meliloti significantly improved the soil maturation and reclamation effect of the dumping,and had a outstanding synergistic effect.