Analysis of Soil and Microbial Characteristics and Microbial Response in Rare Earth Mining Areas in Jiangxi Province, China.

There is a certain connection between the microbial community and functional ora in rare earth mining areas, but the pollution characteristics and pollution metabolic pathways in the mining area are still unclear. The conditions of heavy metals, rare earth elements, and microorganisms after the mining of rare earth mines were studied in this paper. It was found that after mining, all the sampling areas showed low pH and low total organic carbon(TOC), accompanied by high iron and aluminum concentrations. The development of vegetation is closely related to the development level of microorganisms. In the complex environment of rare earth mining areas, the Proteobacteria showed an absolute competitive advantage. In the process of mine environmental recovery, the relative abundance of Acidobacteria will increase signicantly, but with the further development of restoration, the relative abundance of Firmicutes in rare earth mining areas will gradually decrease. There are many genera of bacteria related to the N cycle and heavy metal metabolism in the study area, indicating important metabolic pathways of ammonia nitrogen and heavy metals in rare earth mining areas. At the same time, the study found that there are bacterial genera that promote plant nitrogen xation in the area, further revealing the nitrogen cycle.


Introduction
As we know, rare earth is very important and can be used in electronic devices, the auto industry, aeronautical manufacture, energy conversion, and so on (Alonso et al. . In addition to the rare earth oxides, the injected ammonium ion also displaces a certain amount of soil cationic nutrients at the later stage of displacement, causing soil nutrient loss. Sulfate, as a kind of salt that is di cult to be used by plants, remains in the soil at a concentration of up to 200mg/kg. The precipitation of heavy metal elements and rare earth elements in the soil through cation exchange will inevitably affect the survival of microorganisms and further affect the realization of ecosystem functions. It has been found that biological monitoring can be widely used in the eld of atmospheric deposition by its economical and effective characteristics(Aničić Urošević et al., 2020). However, the research on the interaction of microorganisms with heavy metals and rare earth elements in rare earth mining areas is still insu cient. In particular, rare-earth mining is associated with secondary hazards, such as excessive concentrations of iron and aluminum. In this study, the concentrations of iron and aluminum reached 30g/kg and 103g/kg, respectively. Microbe are very sensitive to high concentrations of salt, so they have to respond to sudden pollution(Ağdağ and Sponza, 2005, Min et al., 2017). Besides, compared with soil physical and chemical properties, soil microorganisms are more sensitive to any small changes in soil or environmental stress. (Cruz-Paredes et al., 2017) .Therefore, the trend of environmental change can be understood and measures can be taken in time (Valentini et al., 2016). The heavy metal elements in the leaching site also have some residual effects on the community structure of microorganisms . The complexity, richness and structural characteristics of the microbial community represent the health level of the ecological environment in a certain region and predict the natural degradation capacity of pollutants to a certain extent. The characteristics of the microbial community under the in uence of the above factors should be fully understood, to judge the soil pollution situation directly in the later stage. Considering that the structure and level of the microbial community in rare earth mining areas are seriously inadequate in the study of rare earth pollution, heavy metal pollution, and other typical pollution, this article was written. This study focused on the pollution of sulfate and heavy metals in the rare earth mining areas and determined the characteristics of iron and aluminum content in the area, the retention of rare earth elements in the area after mining, and the response of internal microorganisms in the area to these factors. At the same time, the characteristics of the microbial community in rare earth mining areas and the response of microorganisms to environmental remediation were investigated.

The study area
The study area is located in Longnan and Dingnan counties, Ganzhou city, Jiangxi province, China. The study area is located in a mountainous area, with hills and mountains accounting for nearly 80% of the area. The whole area is rich in vegetation and partially exposed (caused by human factors). The area has nearly 100 large and small rare earth mines and other types of mineral deposits. Vegetation is dominated by evergreen broad-leaved forests and bamboo forests. With annual or two-year-old short plants, the ground undulates greatly, and slope runoff is easy to form during the rainfall period. Some areas with imperfect vegetation cover are easy to form typical owing water landforms. It is introduced that the original soil in the study area is rich in organic matter, the soil quality is relatively loose, the particles are ner, and the groundwater ion content in the study area is relatively high. Based on the needs of this research, 5 typical and representative sampling points were selected from rare earth mines in the research area. They represent different recovery periods, different mining methods and recovery methods, etc.

sample collection and processing
Soil samples were collected from surface soil at a depth of 5-20 cm(All native soils in the study area). The situation in the study area is shown in Table 1. The detailed location map of the sampling points is shown in Fig. 1. Each sample was divided into two parts. The part of the sample used for testing microorganisms was sieved through a nylon sieve(aperture is 2 mm) to remove stones and plant debris(Sample processing is performed according to the recommendations provided by the testing agency). And then it was sent to Shanghai personal biotechnology Co., Ltd. for testing at low temperatures. Another part of the sample was used for testing of heavy metals and rare earth elements were also sieved through 80 mesh nylon screen and sent to Measurement Unit Northeast Institute of Geography and Agricultural Ecology, CAS for testing after being air-dried and ground(15℃,15 days). When the samples were collected, relatively scattered samples were taken at ve points in each sampling point and mixed to make mixed samples, and repeated three times. Five groups of microbial samples were collected and numbered as A, B, C, D, and E, with a total of 15 samples. Five samples of physical and chemical properties were tested. In those sampling sites, group A is in the late stage of mine recovery after mining, and the restoration methods are mainly clear water leaching. The area is covered by abundant vegetation, evergreen broad-leaved forest and dense bamboo forest, plants are well developed, and decayed branches and leaves are mostly on the surface. Group B is the leaching eld with high elevation. This area is the site for the early stage of restoration. Weeds are growing on the surface, but the weeds in this area grow on the guest soil, collected the soil below the guest soil layer during sample collection. Group C is a multistage permeable reactive barrier (PRB) restoration site, which is located in the gully and surrounded by many trees with obvious leaf cover. Group D is the slope area after heap leaching mining, with obvious erosion, severe surface exposure, basically no plants, and sandy soil mainly. The collection site of group E is similar to that of group A, but the sampling site is concentrated at the terminal of leaching restoration, which is located near the waste collection tank. The small area represents obvious exposure and the large scale is mostly covered by trees.

DNA extraction and high-throughput sequencing
The DNA was quanti ed using Nanodrop, and the DNA was detected for DNA extraction quality by electrophoresis of 1.2% agaric gel. The corresponding primers are designed according to the conservative region of the sequence (The front primer is ACTCCTACGGGAGGCAGCA and the back primer is GGACTACHVGGGTWTCTAAT), and sample-speci c Barcode sequences are added to the apcagus of rRNA gene variable regions (single or continuous multiple) or speci c gene fragments. Fluorescence of PCR ampli cation products with Quant-iT PicoGreen dsDNA Assay Kit and uorescence of PCR ampli cation products with Microplate reader (BioTek, FLx800) as a quantitative instrument and according to the quantitative results of uorescence, the samples are mixed in proportion according to the sequence quantity requirements of each sample. The sequencing library was prepared using Illumina's TruSeq Nano DNA LT Library Prep Kit. First, the library is quality-tested on Agilent Bioanalyzer, using The Agilent High Minaty DNA Kit, Quant-iT PicoGreen dsDNA Assay Kit then quanti es the library on the Promega Quanti Fluor uorescence quanti cation system and dilute the gradient of the quali ed upper-machine sequencing library (Index sequence non-repeatable) and mix in proportion to the required amount of sequencing, and be denatured by NaOH into a single chain and sequenced with high throughput, Finally.

Soil elements analysis
Pre-process the samples according to the test method and the pH was tested with the electrode method,the concentration of Fe Al SO 4

2+
were tested with ICP-AES, the concentration of TOC was tested with potassium dichromate titration, ammonium ions were measured by continuous ow analysis and both heavy metals and rare earth elements are measured by ICP-MS method(Only Hg was tested by uorescence). All samples are subject to quality control to ensure test results.

statistical analysis
The differences of microbial composition in the same group were tested with One-way ANOVA using the software IBM SPSS Statistics 25, followed by the least signi cant difference (LSD) at the 95% con dence level. Study microbial abundance differences in microbial groupings by statistical method to ensure test results. Analysis of microbial species diversity with alpha and beta diversity indices (Whittaker, 1960, R.H.Whittaker, 1972. The correlation between microbial community structure and the content of rare earth elements, heavy metals, and basic physical and chemical properties of the soil was analyzed using Spearman correlation. At the same time, the effect of soil physical and chemical properties on heavy metals and rare earth elements was also analyzed with the help of Spearman correlation. The R was used to analyze the relationship between microorganisms and soil elements.

Characteristics of conventional components and heavy metals
The study tested environmental background factors such as pH, sulfate, TOC and ammonium salts and major heavy metals, these factors represent the environmental damage caused by rare earth mining, and they also affect the survival of indigenous microorganisms and biome structure. As shown in Fig. 2(a), the pH range of soil is 4.37-4.75, all of which show a certain degree of acidity. This data indicates that microorganisms in the rare earth mining areas show a certain degree of acid resistance. From the test data, we can nd that the TOC content of group A is higher than that of other groups, by an order of magnitude. Soil TOC content is between 0.08 % and 2.69 %, except for A, the TOC content of other sites is close to or lower than 0.5%, which proves that the soil properties are close to loam or sandy loam, which is not conducive to the survival of plants and microorganisms. In the Fig. 2(b), the concentration changes of sulfate and ammonia nitrogen in the sampling area are shown, The lowest value of sulfate and ammonium salt is B sample, the highest value is E sample and the concentration gap is large. As mentioned above, point E is the discharge area of in-situ ammonium sulfate leaching, where the retention effect is obvious, while point B is the soil covering planting area. The decrease in concentration indicates that human selective planting and soil improvement in the planting process also have a certain in uence on the original soil layer. The corresponding relationship between the two does not meet the original injection ratio. It is speculated that in addition to its own differences in the soil, there may be more bacteria related to the nitrogen cycle that promote the nitrogen cycle. In the study of heavy metals, it was found that the content of heavy metals in the whole study area was at an acceptable level. In contrast, the heavy metals at point C were the most typical. Such stress promoted the development of functional ora( Fig. 2 (c)). The contents of iron and aluminum were high, reaching the highest levels of 33.13 g/kg and 103.1 g/kg, respectively. The concentration of lead in the tested heavy metal elements is relatively high, reaching 117.38 mg/kg, and other concentrations are low. The data is shown in Fig. 2

(d).
A certain concentration of rare earth elements can be monitored in all soil samples, which is caused by incomplete leaching mining. Soil quality is an important part of ecosystem restoration, and its physical, chemical and biological characteristics are the basis for plant renewal and establishment(Zhang H 2013). Figure 2(e) shows the occurrence characteristics of rare earth elements in the study area, the total amount of rare earth elements at each sampling point and the content of each rare earth element at each point and their corresponding relationships. It is not di cult to see that the contents of rare earth elements at points A and E are higher than those at other points, which is caused by the sampling method of in-situ leaching. There are also certain differences in the proportion of rare earth elements in each sampling point, and the dominant types are quite different, which further affects the microbial community in the site. groups, this result is likely to be caused by environmental factors. The differences between groups of microorganisms in this study are shown in Fig. 3. When the outlier B1 was excluded, the cluster dendrogram based on the weighted pair-group method with arithmetic means (UPGMA) showed that the soil bacterial communities from the A, C were far apart from those in other places (Fig. 3II). Similar to the former two cases, ignoring outlier B1, the two-dimensional ranking diagram of samples analyzed by PCoA also shows the rationality of classi cation (Fig. 3I). It can be seen that certain factors affect the characteristics of the biological community in this region.
Rarefaction curves about the OTUs reached the plateau with the increase of the number of sequences per sample, stressing that the 38, 000 sequences for each sample were su cient to characterize soil bacterial communities in the studied soils. The corresponding alpha diversity index is shown in Table 2. Through the study on the microbial diversity of rare earth mining areas, the species richness in this area is relatively high. Five groups of samples Chao1 index are distributed between 3200 and 4800, and the groups with the highest index and the lowest index are group A and group D, respectively. The Observed species index has A similar distribution pattern, with the highest value still appearing in group A and the lowest values appearing in group D, 4707 and 3,226, respectively. When it comes to the study of species diversity, it can be found that group A still showed certain advantages, while group D showed less obvious disadvantages. This study found that there was no signi cant difference between Simpson index and Shannon index, with both the Simpson index above 0.99 and Shannon index around 10. Then, the diversity, evenness and coverage of sample evolution were analyzed in depth, which was characterized by Faith's PD index, Pielou's evenness index and Good's coverage index respectively. The study found that group A still maintained the highest evenness and group E the lowest evenness. The difference between the two groups was about 0.07, indicating that relative richness level and richness followed the same change rule. The coverage level study found that although the sample diversity index and richness index of group D had no advantages, the coverage level was the highest, but the differences between the groups were minimal, reaching above 0.99, and the sequencing coverage level was high. The OTUs could be divided into different categories, and 11 dominant bacterial phyla with the relative abundances > 1% were obtained, including Proteobacteria, Firmicutes, Actinobacteria, Acidobacteria, Bacteroidetes, Chloro exi, Planctomycetes, Patescibacteria, Verrucomicrobia, Spirochaetes, Gemmatimonadetes. Proteobacteria dominated, accounting for more than a third of the genome, and Firmicutes, the second-largest, accounted for nearly 50 percent of the total. (Fig. 4T). When it came to groups, the dominant phylum of all groups was Proteobacteria(This is because proteobacteria are the largest species of bacteria), and OTUs contained in all groups were ranked in the rst place, while those in the second place were divided. Among them, Actinomycetes were ranked in the second place in group A and group C, with a similar proportion, while Firmicutes were ranked in the second place in group B, group D and group E. Firmicutes also ranked second in the overall level of the community, mainly due to the data volume advantage. However, group A and group C together again also coincides with the previous clustering results, indicating that the factors affecting clustering also affect the development of the microbial community.
At the genus level, the relative abundance is greater than 1.5% were Bacterium, Burkholderiaceae, Gammaproteobacteria, Acidothermus, Paraburkholderia, Pseudomonas, Acidobacteriaceae, Rhodanobacteraceae, Clostridiales. Based on Euclidean distance, the composition of taxa at the genus level was used as the analysis object, and the abundance data of the genus with the average abundance of the top 50 digits were used to draw the heatmap. It can be seen from the heat map data that the bacterial community is divided into two parts, in which group A and C are similar, while group B, D and E are similar, but some differences between group A and group C can be found, which is consistent with the previous PCoA and other analysis.
The development level and abundance level of regional microorganisms are closely related to the geochemical process of the site. The study found that Burkholderiaceae is a typical ammonia nitrogen degrading bacteria (Feng et al., 2017). In this study, it was found that the relative abundance of Burkholderiaceae was very high, indicating that there is obvious ammonia oxidation in the study area. The secondary damage caused by human mine restoration, the natural environment can be restored spontaneously. Research on ammonium conversion in the desert of Oman found that Gammaproteobacteria play a huge role in ammonia oxidation. Sequencing revealed that Gammaproteobacteria's ammonia oxidation gene has the largest copy number (Abed et al., 2015). In Brazil's iron mine studies, it was found that Fe(III) reduction was related to Gammaproteobacteria, Acidobacteriaceae, and Chloro exus(Parker et al., 2017), which further explained the relatively high abundance of these bacteria in the site and also revealed the existence of the study area Fe(III) metabolic pathway. The existence of these genera will also strengthen the survival of plants under the threat of aluminum pollution. It shows that these genera have certain promotion signi cance to the vegetation restoration in the study area(Shi et al., 2020). This nding further illustrates the self-repair ability of the study area.
The Chujaibacter was discovered and named by Korean scientists in 2015. Due to the short time of discovery, there are few related studies, but it is known that the strain is closely related to Metallobacterium Schae eri (Kim et al., 2015). It can be inferred that the bacteria participated in the recovery of heavy metal pollution in the study area, especially the E area where the eluent was discharged. According to the heat map analysis, the Pandoraea genus is very typical in the E study area, and this genus has a strong effect on ammonia nitrogen removal (

Correlations between soil elements and soil microbial communities
To better reveal the characteristics of the in uence of geochemical parameters on the microbial environment, we used R to do a CCA analysis of the study area (Fig. 6), Through screening to remove unreasonable factors, pH, TOC, NH4-N, Al, Cd, Dy, Ho, Er, etc. were determined as in uencing factors for analysis. It was found that the key factors related to the composition of the microbial community can be roughly divided into three parts. Among them, the group controlled by NH4-N is the most obvious. This group is mainly composed of three groups of samples B, D, and E. There is an obvious positive correlation with NH4-N, which further illustrates that there is a certain ammonia nitrogen removal potential and trend in the unrepaired area or the area before the restoration. The TOC and Al in area A have more obvious effects on microorganisms. Further research found that the more abundant Bradyrhizobium in study area A is a very typical acid-tolerant Al-resistant genus(Ozawa et al., 1999), revealing the possible metal metabolism that may occur on the surface of rare earth mining areas. At the same time, the appearance of rare earth elements and high TOC also con rmed that in-situ leaching has less damage to the ecology.
The correlation between soil element characteristics and microbial community diversity index is listed in Table 3. Surprisingly, there is no signi cant correlation between the sulfate and ammonium ions introduced in the rare earth mining process and the species diversity index. Although not signi cant, it can still be found that there is a negative correlation between the above two factors and the α diversity index, indicating that the introduction of ammonium sulfate is not conducive to the survival of microorganisms. According to the correlation coe cient judgment, heavy metal elements and bacteria community diversity did not show a signi cant correlation. But through comparing data can still be found, heavy metal elements in addition to arsenic and almost all negative correlation between the diversity of the biotic community. It shows that the presence of heavy metals is still detrimental to the microbial community. As an essential element for the survival of almost all organisms, C has a great impact on the diversity of the bacterial community and shows a signi cant positive correlation. The correlation coe cient between TOC content and the diversity index of this study is large, with the maximum value of 0.91, which is the impact on the evenness of the microbial community.
Previous studies have found that rare earth ore mining will cause quite obvious in the process of iron and aluminum content increases, iron and aluminum is analyzed emphatically in the survey, the study found that the concentration of aluminum species diversity of microbial communities showed a signi cant positive correlation, the correlation coe cient reached 0.965, so aluminum is one of the important in uencing factors of the microbial community structure of rare earth mining area. The iron content had little effect on the microbial community structure and the whole was not signi cant. Rare earth elements have a certain positive in uence on the diversity and abundance of the community structure, and the correlation coe cient is almost above 0.5, especially Dy, Ho, Er and Y. The contents of these four elements all show a signi cant positive correlation with the diversity of the microbial community, and the correlation coe cient is about 0.9. At the same time, there was a positive correlation between the contents of rare earth elements and the evenness of the microbial community. However, the diversity and coverage of microbial community evolution were negatively correlated with the content of rare earth elements, and the in uence of various elements was signi cant.
The nutrients and vegetation added in the early stage of plant restoration may not necessarily achieve long-term restoration, so the development of microbial community becomes particularly important(Orozco-Aceves et al., 2017). The microbial community can not only indicate the current status of the soil to a certain extent but also respond to environmental changes and participate in participatory remediation. From Table 2, it can be seen that there is a large difference between the alpha diversity index of the three groups of microbial communities of A, B and C and the two groups of D and E. First of all, we found that Chao1 and Observed_species indexes have obvious laws. These two indexes show the species richness of the microbial community. The values of group A are in the rst place. The two index values of group B exceed group C. It is speculated that it is the input of fertilizers and other substances that stimulated the microorganisms of group B during the arti cial repair process, so that they developed rapidly. Given that the area is in the same sedimentary layer and close to each other, we assume that the original soil was the same or similar before the soil was mined. Therefore, we can predict that the effects of arti cial root clefts will have a great impact on the restoration of microbial community richness, and purpose-oriented planting of vegetation can improve the microbial environment of soil. It can be found from the table that the Chao1 index of Groups D and E drops rapidly. Among them, the high concentration of sulfate stimulated some microorganisms, making it di cult to survive. The species richness decreased greatly. In the sampling points of group D, the strong erosion made the TOC in this area only 0.08%, which greatly restricted the development of microbial communities. Shannon index and Simpson index indicated the diversity of the community. There was little difference between the two indexes, but the rule was still obvious. Group A and group C with lush vegetation and group B with arti cial plant restoration had higher indexes, moreover, the value of group A is still the highest. Previous This study found that at the phylum level, the predominant ora was Proteobacteria, Firmicutes, Actinobacteria, Acidobacteria, and Bacteroidetes. From the relative abundance, it can be seen that the microorganisms of these phyla have strong adaptability to the acid environment and the tailings environment of rare earth mines, and play an important role in such an ecosystem. No matter whether it is overall or grouped, Proteobacteria is an absolute dominant phylum, indicating that it has the highest adaptability to harsh environments. This is consistent with the results of previous studies on zinc smelting slag (Youfa et al., 2018)and tailings in Tongling, Shaoguan and Jiangxi(Chen et al., 2013, Liu et al., 2014. It can be seen that Proteobacteria often occupy an advantageous position in the harsh environment of mine tailings. From the phylum level relative abundance graph, we can see that the dominant ora of the two groups A and C are Proteobacteria. The proportion of phylum is far more than that of the other three groups. There is very little development of Firmicutes bacteria in these two groups. This is a clear difference from the other three groups. It can be seen that the Firmicutes in the two groups will be signi cantly reduced after ecological restoration. When studying the difference between Group B and D and E, it is not di cult to nd that the relative abundance of Acidobacteria is signi cantly increased. It can be seen that during the process of ecological restoration, Acidobacteria is the primary active phylum, and is the representative phylum of ecological restoration. Besides, the results also con rmed that plants can cause changes in Acidobacteria, especially in rare earth mining areas. However, it is clear that research on rare earth minerals is still lacking at this stage, and further studies on vegetation types and element types need further research. Further research found that there are corresponding laws not only at the phylum level but also at the genus level. These results indicate that the existence and restoration of plants are of great signi cance to the ecological environment. But to be speci c to the micro-process of ecological environment restoration, further study of gene metabolism is needed.

Research de ciencies and future research
The types of rare earth minerals are extremely complex, but the overall scale is small, and the types of rare earth minerals involved in this study are still insu cient. In this study, the characteristics of soil elements and the response of microorganisms to the environment in the late restoration, early restoration and undisturbed areas were included. However, the number of sampling mines limited the number of sites in the early restoration period, so only one mine was found in the early restoration period. In this study, although it was con rmed that vegetation development had a certain impact on biology, due to the small scale of rare earth mines, vegetation coverage was not quantitatively studied, and the impact of vegetation types and growth conditions on microorganisms was not further analyzed.
After studying the characteristics of soil elements and the corresponding characteristics of microorganisms in the environment in the rare earth mining area, further research will be performed. First of all, in the mining eld, by testing the regional characteristics of microorganisms, the occurrence of rare earth elements in the region can be analyzed to achieve rapid screening of mines, but speci c indicator microorganisms still need in-depth research. Secondly, Proteobacteria microorganisms can be used as an option for rapid repair of the site, and a better solution of mine repair through the combination of multiple technologies. To make up for the shortcomings of this research, the later research will nd more research sites to enrich the types of mines, and at the same time try to quantify the vegetation coverage level, and further re ne the vegetation type and vegetation root development level. Study the mechanism of vegetation's impact on microorganisms and the environment and verify the current results. Finally, vegetation and microorganisms will be restored together.

Conclusion
The interaction between the indigenous microbial communities of rare earth mines and the geochemical characteristics and processes of the mine itself is the key to reveal the biogeochemical evolution of rare earth mines. This study selected a typical research area of a typical mining area and found that the microbial community will change as the mine recovers.
In general, the soil environment of the rare earth tailings site is signi cantly affected by the mining effect. Among them, the soil of the research site shows acidic characteristics, and the pH is less than 4.8. At the same time, the TOC content in the soil is seriously insu cient. There are a lot of iron and aluminum elements in the soil after mining, which is caused by the residue of iron-rich and aluminum-rich clay minerals after leaching, and the aluminum element content reaches 103 g/kg. The content of rare earth elements in the collected soil samples is quite different, and the analysis found that the content of rare earth elements is positively correlated with TOC and negatively correlated with Pb content. This internal relationship needs further exploration. Because the mineral leaching agent is an ammonium sulfate solution, the content of sulfate in the soil is generally high, The drainage area repair in the in-situ leaching area has a lag effect, and long-term management should be realized. The characteristics of the microbial community in different recovery periods are different. NH4-N has the most obvious impact on microorganisms in the unrecovered area or at the initial stage of recovery.
The microbial community can make different responses to different environments, and the development of vegetation directly affects the structural characteristics of the microbial community. The regions with relatively complete vegetation coverage (group A) have the highest alpha diversity index, and Several indicators are positively correlated with the development of vegetation. The dominant bacteria in the study area are Proteobacteria and the relative abundance of Proteobacteria in each sampling area is the highest, indicating that Proteobacteria have the strongest adaptability to the rare earth mine environment. In the process of mine restoration, the bacterial community will also change accordingly, which is mainly re ected in the gradual decrease of the relative abundance of Firmicutes and the gradual increase of the relative abundance of Acidobacteria. Among the research points, the typical bacterial genera are mostly related to the nitrogen cycle or plant nitrogen xation(Burkholderiaceae, Gammaproteobacteria, Gemmatimonas) and heavy metal metabolism(Chujaibacter). Among them, point C is the most typical, indicating that multi-stage PRB restoration has a good role in promoting ecological restoration, especially the restoration of ammonia nitrogen.