Method for maintaining microbial diversity of reclamation soil in loess sandstorm coal mine area

Abstract

The invention belongs to the technical field of mining area ecological restoration and soil microbial engineering, and particularly relates to a loess sandstorm coal mine area reclaimed soil microbial diversity maintaining method. A'plant-microorganism-soil 'coordinated regulation and control system is designed, a'strip-type crop rotation' planting mode is provided, and microbial communities with specific functions are synchronously inoculated, so that a microbial network structure of the reclaimed soil is reconstructed, a microbial interaction network is constructed, and the complexity and stability of the reconstructed microbial network are evaluated; and dynamically regulating and controlling the reconstructed soil microorganism system according to an evaluation result to stably maintain the biological diversity of the micro soil. The method provided by the invention is suitable for mining area reclamation scenes with strong drought and wind erosion and heavy metal pollution, and has the advantages of wide adaptability, high microbial community construction efficiency, strong stress resistance and disturbance resistance and the like. And a systematized and refined regulation and control path can be provided for microbial diversity recovery of the reclaimed soil in the loess sandstorm coal mine area.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ecological restoration and soil microbial engineering in mining areas, and particularly relates to a method for maintaining microbial diversity of reclaimed soil in a loess windy and sandy coal mining area. BACKGROUND

[0002] With the continuous advancement of coal resource exploitation activities to ecologically sensitive areas, the loess windy and sandy area has become an important gathering place for coal mine reclamation engineering. However, the original ecosystem in this area is fragile, the climate is dry and windy, the reclaimed soil generally presents the characteristics of unstable structure, low organic matter content, degraded physicochemical properties and single microbial community, which seriously restricts the ecological continuity and system stability of the soil function recovery and vegetation construction process. Microbial community, as the core driving factor of soil ecological process, directly determines the nutrient cycling efficiency, pollution stress buffering capacity and plant symbiotic potential, and is a key limiting link that needs to be broken through in the reconstruction of mining soil.

[0003] Existing studies have shown that plant diversity configuration and functional microbial inoculation can improve the ecological adaptability of reclaimed soil to a certain extent. However, such methods mainly focus on single-factor regulation, ignore the spatial heterogeneity and dynamic coordination mechanism among plant-microorganism-soil systems, and are difficult to build a long-term stable micro-ecological structure. SUMMARY

[0004] In order to solve the problem that the existing plant diversity configuration and functional microbial inoculation method mainly focuses on single-factor regulation, ignores the spatial heterogeneity and dynamic coordination mechanism among plant-microorganism-soil systems, and is difficult to build a long-term stable micro-ecological structure, the application aims to provide a method for maintaining microbial diversity of reclaimed soil in a loess windy and sandy coal mining area, which is highly targeted, has high regulation precision, wide ecological adaptability and strong implementation flexibility. In order to achieve the above-mentioned purpose, the application adopts the following technical scheme.

[0005] The application provides a method for maintaining microbial diversity of reclaimed soil in a loess windy and sandy coal mining area, comprising the following steps: S1, according to the soil characteristics (loose structure, poor organic matter, easy wind erosion and drought, and heavy metal residues) of the reclaimed land in the loess windy and sandy coal mining area, a plant rotation system is designed to improve the soil microenvironment and provide protection for microbial survival. According to the time sequence, the plant rotation system is divided into three periods, 0-1 years for the early reclamation period, 2-3 years for the middle reclamation period, and 4-5 years for the late reclamation period,

[0006] S2, based on the soil characteristics of the loess sand coal mine reclamation area and the adaptability of microorganisms to it, key functional strain screening is carried out, and the screened heavy metal transformation functional bacteria, mycorrhizal fungi and nitrogen-fixing bacteria form a "heavy metal transformation functional bacteria-mycorrhizal fungi-nitrogen-fixing bacteria" synergistic functional flora, which cooperates with plants to form a "plant-microorganism" synergistic stable reclamation soil microenvironment mode.

[0007] Among them, each functional strain needs to meet the following standards: Heavy metal transformation functional bacteria: heavy metal removal rate and environmental tolerance are the core indicators.

[0008] Mycorrhizal fungi: root system infection efficiency and soil aggregate promotion ability are the core indicators.

[0009] Nitrogen-fixing bacteria: nitrogen contribution rate and host specificity are the indicators.

[0010] S3, from the early reclamation to the later reclamation, the soil pH value and the soil water content of the original soil in the loess area are taken as the standard, the soil pH value and the soil water content of the loess sand coal mine reclamation area are adjusted, and the carbon-nitrogen ratio of the soil of the loess sand coal mine reclamation area is adjusted, and then the physicochemical properties of the soil of the loess sand coal mine reclamation area are adjusted, so that it is suitable for the survival of the above-mentioned heavy metal transformation functional bacteria, mycorrhizal fungi and nitrogen-fixing bacteria, forming a "microorganism-plant-soil" synergistic system, and providing a suitable living space for microorganisms.

[0011] S4, directional inoculation of the bacterial flora is carried out.

[0012] S5, based on the plant rotation system, a strip planting mode is adopted, vegetation planting is carried out in the loess sand coal mine reclamation area, and a constructed loess sand coal mine reclamation area is obtained.

[0013] S6, taking the microbial community characteristics and physicochemical properties of the original soil in the loess area as the control standard, using high-throughput 16S / ITS sequencing technology combined with random matrix theory, the microbial diversity indicators of the original soil in the loess area and the soil of the constructed loess sand coal mine reclamation area are obtained, and the microbial interaction network is constructed respectively, to measure the complexity and stability of the soil microbial community.

[0014] S7, according to the constructed microbial interaction network of the original soil in the loess area, the microbial interaction network of the soil of the constructed loess sand coal mine reclamation area is evaluated, and according to the evaluation result, the microbial diversity of the soil of the constructed loess sand coal mine reclamation area is dynamically regulated.

[0015] The method provided by the application is a loess wind-sand coal mine area-oriented reclaimed soil micro-ecosystem reconstruction method, which integrates plant strip space configuration, multifunctional microorganism composite inoculation and community stability dynamic evaluation technology, cooperatively regulates soil biodiversity, physical and chemical structure and ecological function, can realize the high complexity and high robustness evolution process of the microbial community under pollution stress, and provides theoretical support and technical path for the stable recovery of the mine area ecosystem and the reconstruction of soil function.

[0016] Further, in S1, the plant rotation system is: in the early stage of reclamation, planting Hippophae rhamnoides and leguminous plants; in the middle stage of reclamation, planting Hippophae rhamnoides and Chenopodium quinoa; and in the late stage of reclamation, planting Hippophae rhamnoides and native shrubs.

[0017] Further, in S2, the selected heavy metal transformation functional bacteria are Bacillus megaterium, the selected mycorrhizal fungi are Glomus, and the selected nitrogen-fixing bacteria are Rhizobium japonicum.

[0018] Further, in S3, the method for adjusting the carbon-nitrogen ratio of the soil of the loess wind-sand coal mine area reclamation land is: in the early stage of reclamation, adding decomposed cow and sheep manure to the soil of the loess wind-sand coal mine area reclamation land, and adjusting the carbon-nitrogen ratio of the soil of the loess wind-sand coal mine area reclamation land to be consistent with the carbon-nitrogen ratio of the soil of the original loess area soil; and in the late stage of reclamation, the carbon-nitrogen ratio of the soil of the loess wind-sand coal mine area reclamation land is maintained consistent with that in the early stage of reclamation by the method of straw returning.

[0019] Further, in S3, the method for adjusting the pH value of the soil of the loess wind-sand coal mine area reclamation land is: if the soil pH value is >8.0, then adding gypsum and sulfur powder to adjust the soil pH value to 7.0-7.5; if the soil pH value is <6.5, then applying wood ash to adjust the soil pH value to 7.0-7.5; and if the soil pH value is 6.5-8.0, no adjustment is needed.

[0020] Further, in S3, the method for adjusting the water content of the soil of the loess wind-sand coal mine area reclamation land is: using drip irrigation technology to adjust the soil water content of the soil of the loess wind-sand coal mine area reclamation land to be consistent with the soil water content of the original loess area soil.

[0021] Further, in S4, the functional bacteria group is made into a spore suspension, the plant roots of the plant subjected to plant rotation are dipped into the spore suspension for root dipping treatment; and every spring, the plant is supplemented with a bacterial agent through a drip irrigation system. The bacterial agent is a spore suspension containing a humic acid carrier.

[0022] Further, in S5, the method for planting vegetation in the reclamation land of the loess sand mine area is as follows: the reclamation land of the loess sand mine area is divided into multiple strips, and the principle of "planting one strip of Hippophae rhamnoides L. between three strips of sand" is adopted to plant Hippophae rhamnoides L. and legume plants in the early reclamation period, the planting area of Hippophae rhamnoides L. accounts for 25% of the total area of the reclamation land of the loess sand mine area; Hippophae rhamnoides L. and Chenopodium quinoa are planted in the middle reclamation period, at this time, the planting area of Hippophae rhamnoides L. accounts for 50% of the total area of the reclamation land of the loess sand mine area; Hippophae rhamnoides L. and native shrubs are planted in the late reclamation period, at this time, the planting area of Hippophae rhamnoides L. accounts for 75% of the total area of the reclamation land of the loess sand mine area.

[0023] Further, in S6, the microbial diversity index includes Shannon index and Simpson index; the complexity and stability of the soil microbial community are achieved by calculating the network average connectivity and modularity of the microbial interaction network of the constructed loess area native soil to the microbial interaction network of the constructed reclamation land of the loess sand mine area.

[0024] Further, in S7, according to the evaluation result, the method for dynamically regulating the microbial diversity of the soil of the constructed reclamation land of the loess sand mine area is as follows: if the modularity of the microbial interaction network of the constructed reclamation land of the loess sand mine area significantly decreases, and the network average connectivity and average clustering coefficient index are lower than the reference value of the microbial community of the loess area native soil, the feedback regulation is performed by adjusting the type and proportion of plants in the strip rotation planting mode and functional strains in the functional flora, and supplementing bacterial agents every year.

[0025] The bacterial agent is a spore suspension containing a humic acid carrier.

[0026] Compared with the prior art, the present application has the following beneficial effects: 1. The application provides a method for maintaining the microbial diversity of reclaimed soil in a loess wind-sand coal mine area. The method provided by the application first designs a plant rotation system according to the soil characteristics of the reclaimed land in the loess wind-sand coal mine area. Then, based on the soil characteristics of the reclaimed land in the loess wind-sand coal mine area and the adaptability of microorganisms to them, key functional strains are screened. The screened heavy metal conversion functional bacteria, mycorrhizal fungi and nitrogen-fixing bacteria form a "heavy metal conversion functional bacteria-mycorrhizal fungi-nitrogen-fixing bacteria" synergistic functional bacterial group, and a "plant-microorganism" synergistic stable soil microenvironment model is formed. Then, by adjusting the carbon-nitrogen ratio (C / N) of the soil, the pH value of the soil and the water content of the soil, the soil physical and chemical properties are regulated, a "microorganism-plant-soil" synergistic system is formed, and a suitable living space is provided for microorganisms. Then, directional inoculation of microorganisms is carried out. A "striped rotation" planting mode is adopted for vegetation planting in the area to be reclaimed. The microbial community characteristics and physicochemical properties of the original soil in the loess area are used as a control standard. High-throughput 16S / ITS sequencing technology is used in combination with random matrix theory to obtain the microbial diversity indicators of the original soil in the loess area and the soil of the constructed reclaimed land in the loess wind-sand coal mine area, and microbial interaction networks are constructed respectively to measure the complexity and stability of the soil microbial community. Finally, the microbial interaction network of the original soil in the loess area is used to evaluate the microbial interaction network of the soil of the constructed reclaimed land in the loess wind-sand coal mine area, and the microbial diversity of the soil of the constructed reclaimed land in the loess wind-sand coal mine area is dynamically regulated according to the evaluation results. The application can synergistically regulate soil biodiversity, physicochemical structure and ecological function by designing a "plant-microorganism-soil" synergistic regulation system, integrating plant strip space configuration, multifunctional microbial composite inoculation and community stability dynamic evaluation technology, realizing high complexity and high robustness evolution process of microbial community, providing a technical path for stable recovery of mine ecosystem and reconstruction of soil function, and solving the problem that existing plant diversity configuration and functional microbial inoculation methods mainly focus on single factor regulation and ignore the spatial heterogeneity and dynamic synergistic mechanism among plant-microorganism-soil systems, and it is difficult to construct a long-term stable microecological structure.

[0027] 2、The application firstly provides a suitable living space for indigenous microorganisms in the soil of the reclamation area by designing a "plant-microorganism-soil" synergistic regulation system; then proposes a "strip cropping" planting mode to construct an ecological strip with complementary plant functions in space; synchronously inoculates microbial communities with specific functions to reconstruct the microbial network structure of the reclaimed soil, and to enhance the ability of the system to resist heavy metal stress and ecological disturbance; takes the microbial community characteristics and physicochemical properties of the original soil in the loess wind-sand area as the control standard, obtains the microbial diversity index through high-throughput 16S / ITS sequencing technology, and constructs a microbial interaction network based on the sequencing results to evaluate the complexity and stability of the microbial network in the system; finally, according to the evaluation results, the reconstructed soil microbial system is dynamically regulated to stably maintain the soil microbial diversity. This method is suitable for the reclamation scene of the mine area with strong drought and wind erosion and heavy metal pollution, has the advantages of wide adaptability, high efficiency of microbial community construction, strong stress resistance and disturbance resistance, etc. It can provide a systematic and refined regulation path for the recovery of soil microbial diversity in the loess wind-sand coal mine area, significantly improve the stability and sustainability of the ecological system of the reclaimed land, and has good popularization and application prospect, and has important significance for the development of soil reconstruction and mine ecological restoration technology in ecologically fragile mine areas.

[0028] 3、The application discloses a method for maintaining soil microbial diversity in a loess wind-sand coal mine area reclamation, and establishes a complete and multi-dimensional collaborative soil microbial diversity maintenance method, which comprises: phased plant rotation design, multifunctional microbial complex inoculation, accurate regulation of soil physicochemical properties, strip space configuration and dynamic evaluation. The method significantly improves the soil microbial diversity and network stability in the reclaimed soil through four-dimensional collaboration of "space configuration-function bacteria group-physical and chemical regulation-dynamic evaluation". The phased design takes into account short-term adaptability and long-term resilience, especially the ecological resilience under heavy metal pollution stress, and provides a popularized technical path for soil function reconstruction and stable recovery of the ecological system in the loess wind-sand coal mine area. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The total design flowchart in the application.

[0030] Figure 2 The "strip cropping" planting mode in the application is shown in the figure; wherein: A figure is for the early stage of reclamation (0 years to 1 year); B figure is for the middle stage of reclamation (2-3 years); C figure is for the late stage of reclamation (4-5 years).

[0031] Figure 3 The soil microbial diversity index in the reclamation area in the application is shown in the figure; wherein: Figure A is a diagram of the Shannon index of the soil reclamation area; Figure B is a diagram of the Simpson index of the soil reclamation area. DETAILED DESCRIPTION

[0032] The present application will be described in detail below with reference to the accompanying drawings and specific examples, but should not be understood as limiting the present application. If not specifically stated, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, if not specifically stated, can be obtained from commercial channels.

[0033] The mining area in the following examples is located in the loess plateau hilly region bordering the Mu Us sandy land, and the soil is mainly wind-sand soil and hard soil, with characteristics such as loose structure, large terrain undulation, thick loess cover, poor erosion resistance, and extremely easy to be eroded by wind. The original soil physicochemical property parameters of the mining area are as follows:

[0034] The C / N value is 7.79±1.27; the pH value is 7.23±0.14; and the soil moisture content is 8.89%±1.25%. Among them, the C / N value refers to the mass ratio of carbon (C) and nitrogen (N) in the soil, i.e. the ratio of soil organic carbon content to total nitrogen content. This index is an important parameter for evaluating soil quality, organic matter decomposition rate and nitrogen supply capacity.

[0035] Example 1 A method for maintaining the microbial diversity of a loess wind-sand coal mine reclamation soil (as shown in Figure 1 ), comprising the following steps: First, according to the characteristics of the reclamation soil of the mining area (loose structure, poor organic matter, easy to be eroded by wind and drought, and heavy metal residues), a plant rotation system is designed. According to the time sequence, the plant rotation system is divided into three periods: 0-1 years for the early reclamation period, 2-3 years for the middle reclamation period, and 4-5 years for the late reclamation period. The specific plant rotation system is as follows:

[0036] In the early reclamation period (0-1 years), "sea buckthorn + alfalfa" is planted; in the middle reclamation period (2-3 years), "sea buckthorn + chenopodium" is planted; and in the late reclamation period (4-5 years), "sea buckthorn + caragana, oil million" is planted.

[0037] Second, according to the adaptability of microorganisms to the microenvironment of the reclamation soil of the mining area, the key functional strains selected are Bacillus megaterium N3 ( Bacillus megaterium N3) and Bacillus megaterium Z-y3 ( Bacillus megaterium Z-y3), arbuscular mycorrhizal fungi are Claroideoglomus etunicatum , and nitrogen-fixing bacteria are Rhizobium japonicum ( Bradyrhizobium japonicumThe soybean rhizobium was composed of Bacillus megaterium N3 and Bacillus megaterium Z-y3, arbuscular mycorrhizal fungi, and nitrogen-fixing bacteria to form a synergistic functional group of "heavy metal transforming functional bacteria-mycorrhizal fungi-nitrogen-fixing bacteria".

[0038] Among them, Bacillus megaterium N3 ( Bacillus megaterium N3) and Bacillus megaterium Z-y3 ( Bacillus megaterium Z-y3) are heavy metal transforming bacteria, all purchased from the Agricultural Culture Collection of China (ACCC).

[0039] Arbuscular mycorrhizal fungi Claroideoglomus etunicatum It is an mycorrhizal fungus, purchased from the Bank of Glomeromycota in China (BGC), Institute of Plant Nutrition and Resource Environment, Beijing Academy of Agricultural and Forestry Sciences.

[0040] Soybean Rhizobium ( Bradyrhizobium japonicum The bacteria were nitrogen-fixing and were purchased from the Agricultural Culture Collection of China (ACCC).

[0041] The third step is to adjust the soil's physical and chemical properties, changing the soil's C / N ratio from 12.91±2.35 to 7.79±1.27; the soil pH value from 8.31±0.73 to 7.23±0.14; and the soil moisture content from 6.38%±0.02% to 8.89%±1.25%.

[0042] The fourth step involves adjusting the soil pH and moisture content of the reclaimed land in the Loess Plateau coal mining area from the initial to the later stages of reclamation, using the original soil pH and moisture content as standards. Simultaneously, the carbon-nitrogen ratio of the soil in the reclaimed land is adjusted to regulate its physicochemical properties, making it suitable for the survival of functional microorganisms. Targeted inoculation of these functional microorganisms is then carried out. Details are as follows:

[0043] In the early stages of reclamation, spore suspensions of Bacillus megaterium N3, Bacillus megaterium Z-y3, arbuscular mycorrhizal fungi, and soybean rhizobium are prepared and used for root dipping treatment of sea buckthorn seedlings. Every spring, microbial agents (containing humic acid carriers) are supplemented through the drip irrigation system to maintain microbial activity.

[0044] The preparation method of the spore suspension is as follows: (1) Activation: Inoculate Bacillus megaterium N3 onto nutrient agar and culture at 30°C for 7 days until a large number of mature spores or buds are produced on the surface of the slant.

[0045] Inoculate Bacillus megaterium Z-y3 to nutrient agar, and incubate at 30°C for 7 days until a large number of mature spores or spores are produced on the surface of the slope.

[0046] Inoculate arbuscular mycorrhizal fungi to potato dextrose agar medium (PDA), and incubate at 28°C for 7 days until a large number of mature spores or spores are produced on the surface of the slope.

[0047] Inoculate Rhizobium sojae to yeast mannitol agar medium (YMA), and incubate at 32°C for 7 days until a large number of mature spores or spores are produced on the surface of the slope.

[0048] (2) Spore collection: 5 mL of sterile normal saline containing 0.05% wt Tween-80 was added to the culture mature slope, and the spores or bacteria on the surface of the medium were gently scraped with a sterile spatula. The suspension was transferred to a triangular flask containing sterile glass beads, and shaken for 15 minutes (200 r / min) to fully disperse the spores.

[0049] (3) Filtration and purification: the above suspension was filtered with 8 layers of sterile gauze to remove mycelium fragments and medium residues, and the filtrate was collected in a sterile centrifuge tube. The supernatant was taken after standing at 4°C for 30 minutes, and the single bacterial suspension was obtained.

[0050] (4) Mixing and preservation: the above prepared single bacterial suspension was mixed in equal volume, and the composite functional bacterial flora spore suspension was obtained. The composite functional bacterial flora spore suspension is referred to as spore suspension, and the concentration of the spore suspension is 1×10 6 CFU / g.

[0051] The microbial inoculant is a spore suspension containing humic acid carrier. The addition amount of humic acid carrier in the spore suspension is 20% (mass percent), that is, the spore suspension and the humic acid carrier are mixed in a mass ratio of 4:1 to obtain the spore suspension containing the humic acid carrier.

[0052] Step 5, based on the plant rotation system, a strip rotation planting pattern is adopted to plant vegetation in the reclamation land of the loess sandy coal mine area, and the constructed reclamation land of the loess sandy coal mine area is obtained. Specifically, the entire soil reclamation area is divided into 16 strips, which are numbered 1-16 in order from left to right. In the early stage of reclamation (0-1 years), sea buckthorn is planted in strips 1, 5, 9 and 13, and the remaining strips are all planted with alfalfa, and the planting area of sea buckthorn accounts for 25% of the total area of the soil reclamation area; in the middle stage of reclamation (2-3 years), sea buckthorn is continued to be planted in strips 2, 6, 10 and 14, and the remaining strips are all planted with Chenopodium quinoa, at this time the planting area of sea buckthorn accounts for 50% of the total area of the soil reclamation area; in the late stage of reclamation (4-5 years), sea buckthorn is continued to be planted in strips 3, 7, 11 and 15, and native shrubs such as Caragana and oil are planted in the remaining strips 4, 8, 12 and 16, at this time the planting area of sea buckthorn accounts for 75% of the total area of the soil reclamation area.

[0053] The strip rotation planting pattern is shown in the following figure: Figure 2 .

[0054] The soil reclamation area is the reclamation land of the loess sandy coal mine area.

[0055] Step 6, the Shannon index and Simpson index of the soil reclamation area are calculated using high-throughput 16S / ITS sequencing technology, and the calculation results are as follows: Figure 3 .

[0056] With the increase of reclamation time, the Shannon index and Simpson index are constantly rising, and they are more and more close to the original soil microbial diversity in the loess area, indicating that the microbial diversity of the soil reclamation area is increasing year by year.

[0057] Step 7, based on the high-throughput sequencing results, the microbial interaction network is constructed using random matrix theory, and the connectivity and modularity of the network are calculated, and the calculation results are shown in Table 1. The evaluation results show that the complexity and stability of the soil microbial community are lower than those of the control area, but are gradually increasing.

[0058] Table 1 Stability index table of microbial interaction network From Table 1, it can be seen that the modularity, average connectivity and average clustering coefficient of the soil microbial community in the reclamation area at different reclamation times are lower than those of the original soil but show a trend of increasing year by year. The above results show that the complexity and stability of the soil microbial community in the reclamation area are recovering year by year, which ensures the effective maintenance of microbial diversity.

[0059] According to the above evaluation results, the plant-microorganism synergistic effect cycle is prolonged to regulate, and finally the stable maintenance of the microbial diversity of the reclaimed soil is realized.

[0060] In conclusion, the method for maintaining microorganism diversity of loess windy and sandy coal mine area reclaimed soil can effectively solve the problem that it is difficult to construct a long-term stable micro-ecological structure in the loess windy and sandy coal mine area, through the design of a "plant-microorganism-soil" synergistic regulation system, the integration of plant strip space configuration, multifunctional microorganism composite inoculation and community stability dynamic evaluation technology, the soil biological diversity, physical and chemical structure and ecological function can be synergistically regulated, the high complexity and high robustness evolution process of the microbial community is realized, and a technical path is provided for the stable recovery of the mine area ecosystem and the reconstruction of soil function.

[0061] It should be noted that when a numerical range is involved in the present application, both endpoints of each numerical range and any number between the two endpoints can be selected, and in order to prevent repetition, the preferred embodiments are described in the present application.

[0062] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic creative concept, and all changes and modifications fall within the scope of the present application.

Claims

1. A method for maintaining microbial diversity in reclaimed soil in a loess sandstorm coal mine area, characterized by, Includes the following steps: S1. Based on the soil characteristics of the reclaimed land in the Loess Sandy Coal Mining Area, a plant rotation system is designed. According to the time sequence, the plant rotation system is divided into three periods: 0-1 years as the initial stage of reclamation, 2-3 years as the middle stage of reclamation, and 4-5 years as the later stage of reclamation. S2. Based on the soil characteristics and the adaptability of microorganisms to the reclaimed land in the loess sandy coal mining area, key functional strains are screened, and the screened heavy metal transforming functional bacteria, mycorrhizal fungi and nitrogen-fixing bacteria are combined to form a synergistic functional bacterial community of "heavy metal transforming functional bacteria-mycorrhizal fungi-nitrogen-fixing bacteria". S3. From the early to the late stage of reclamation, using the soil pH and soil moisture content of the original soil in the Loess Plateau as standards, adjust the soil pH and soil moisture content of the reclaimed land in the Loess Plateau wind-blown coal mining area, and at the same time adjust the carbon-nitrogen ratio of the soil in the reclaimed land in the Loess Plateau wind-blown coal mining area, thereby regulating the physicochemical properties of the soil in the reclaimed land in the Loess Plateau wind-blown coal mining area to make it suitable for the survival of the functional microbial community. S4. Perform targeted inoculation of the aforementioned functional microbial communities; S5. Based on the plant rotation system, a strip rotation planting pattern is adopted to plant vegetation on the reclaimed land of the loess sandy coal mining area to obtain the constructed reclaimed land of the loess sandy coal mining area. S6. Using the microbial community characteristics and physicochemical properties of the original soil in the Loess Plateau as a control standard, high-throughput 16S / ITS sequencing technology and random matrix theory were used to obtain the microbial diversity indicators of the original soil in the Loess Plateau and the reclaimed soil in the Loess Plateau aeolian coal mining area. Microbial interaction networks were constructed to measure the complexity and stability of the soil microbial community. S7. The microbial interaction network of the original loess soil is evaluated based on the constructed microbial interaction network of the loess aeolian coal mining area. Based on the evaluation results, the microbial diversity of the soil in the constructed loess aeolian coal mining area is dynamically regulated.

2. The method of claim 1, wherein, In S1, the plant rotation system is as follows: in the early stage of reclamation, sea buckthorn and legumes are planted; in the middle stage of reclamation, sea buckthorn and quinoa are planted; and in the later stage of reclamation, sea buckthorn and native shrubs are planted.

3. The method according to claim 1, characterized in that, In S2, the heavy metal conversion functional bacteria are Bacillus megaterium, Bacillus megaterium , the mycorrhizal fungi are arbuscular mycorrhizal fungi (AMF), and the nitrogen-fixing bacteria are Rhizobium japonicum, Bradyrhizobium japonicum .

4. The method of claim 1, wherein, In S3, the method for adjusting the carbon-nitrogen ratio of the soil in the reclaimed land of the Loess Sandy Coal Mine Area is as follows: In the early stage of reclamation, well-rotted cow and sheep manure is added to the soil in the reclaimed land of the Loess Sandy Coal Mine Area to adjust the carbon-nitrogen ratio of the soil in the reclaimed land of the Loess Sandy Coal Mine Area to be consistent with the carbon-nitrogen ratio of the original soil in the Loess area; in the later stage of reclamation, the carbon-nitrogen ratio of the soil in the reclaimed land of the Loess Sandy Coal Mine Area is maintained to be consistent with that in the early stage of reclamation by returning straw to the field.

5. The method of claim 1, wherein, In S3, the method for adjusting the soil pH value of the reclaimed land in the loess sandy coal mining area is as follows: if the soil pH value is >8.0, gypsum and sulfur powder are added to adjust the soil pH value to 7.0~7.5; if the soil pH value is <6.5, wood ash is applied to adjust the soil pH value to 7.0~7.5; if the soil pH value is 6.5~8.0, no adjustment is required.

6. The method according to claim 1, characterized in that, In S3, the method for adjusting the soil moisture content of the reclaimed land in the loess sandy coal mining area is as follows: drip irrigation technology is used to adjust the soil moisture content of the reclaimed land in the loess sandy coal mining area to be consistent with the soil moisture content of the original soil in the loess area.

7. The method according to claim 1, characterized in that, In S4, the functional microbial community is made into a spore suspension, and the roots of plants undergoing crop rotation are immersed in the spore suspension for root dipping treatment; and every spring, the microbial agent is supplemented to the plants through a drip irrigation system. The bacterial agent is a spore suspension containing a humic acid carrier.

8. The method according to claim 1, characterized in that, In S5, a strip-type crop rotation planting pattern is adopted. The method of planting vegetation on the reclaimed land in the loess sandy coal mining area is as follows: the reclaimed land in the loess sandy coal mining area is divided into multiple strips, and the principle of "planting one strip of sea buckthorn every three strips" is adopted. In the early stage of reclamation, sea buckthorn and leguminous plants are planted, and the planting area of ​​sea buckthorn accounts for 25% of the total area of ​​the reclaimed land in the loess sandy coal mining area; in the middle stage of reclamation, sea buckthorn and quinoa are planted, and at this time the planting area of ​​sea buckthorn accounts for 50% of the total area of ​​the reclaimed land in the loess sandy coal mining area; in the later stage of reclamation, sea buckthorn and native shrubs are planted, and at this time the planting area of ​​sea buckthorn accounts for 75% of the total area of ​​the reclaimed land in the loess sandy coal mining area.

9. The method according to claim 1, characterized in that, In S6, the microbial diversity indicators include the Shannon index and the Simpson index; the complexity and stability of the soil microbial community are measured by calculating the average connectivity and modularity of the microbial interaction network of the constructed native loess soil to the constructed microbial interaction network of the reclaimed loess sandy coal mining area.

10. The method according to claim 1, characterized in that, In S7, based on the evaluation results, the method for dynamically regulating the microbial diversity of the soil in the reclaimed land of the Loess-sand coal mining area is as follows: if the modularity of the microbial interaction network of the soil in the reclaimed land of the Loess-sand coal mining area decreases significantly, and the average connectivity and average clustering coefficient of the network are lower than the reference values ​​of the microbial community of the original soil in the Loess area, then the type and proportion of plants in the strip rotation planting pattern and functional strains in the functional microbial community are adjusted, and microbial agents are added annually for feedback regulation. The bacterial agent is a spore suspension containing a humic acid carrier.

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