A microbial-local plant multi-stage cooperation-based ecological restoration method for tailing ponds in south China

Abstract

The application discloses a kind of based on microorganism-local plant multistage coordination's ecological restoration method of tailing pond in south China, first directional screening pioneer layer, build group layer and landscape layer three levels of pollution-tolerant local plant, simultaneously from local tailing pond rhizosphere soil in situ isolation nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, three types of functional microbial community of stress resistance microorganism;Multilevel three-dimensional collaborative protection structure is constructed, and soil structure is optimized by bacteria-plant cooperation, and the saturated hydraulic conductivity of slope soil is greatly reduced, and runoff erosion is resisted.The application is adapted to the exclusive environment of south China region, and the survival rate of vegetation is high, the repair cycle is short, the anti-scouring capacity is strong, the survival rate of vegetation after repair is increased by more than 50%, the saturated hydraulic conductivity of soil is reduced by more than 90%, and rapid, stable and long-acting ecological restoration is realized.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology for mine tailings ponds, and in particular to an ecological restoration method for tailings ponds in South China based on multi-level synergy between microorganisms and native plants. Background Technology

[0002] Tailings ponds are sites where tailings are deposited after mining operations. Their slopes are characterized by poor soil and high levels of pollutants. South China has a unique climate with high temperatures, abundant rainfall, and concentrated precipitation, making tailings pond slopes highly susceptible to runoff erosion. This leads to soil loss, difficulty in vegetation survival, and other problems, severely damaging the surrounding ecological environment and hindering the reuse of land resources.

[0003] Currently, existing tailings dam ecological restoration methods mostly employ exotic plants or single restoration models, and are largely general-purpose technologies with the following significant drawbacks: First, poor adaptability, with most methods using exotic or common native plants without selecting specific species tailored to the hot, rainy, and infertile soil characteristics of South China, resulting in low survival rates; second, simplistic restoration models, often involving single plants or single microorganisms, or simple microorganism-plant combinations, failing to form a hierarchical, synergistic, and dynamically regulated system, making it difficult to address multiple needs such as erosion resistance, soil improvement, and vegetation stability; third, insufficient erosion resistance design, failing to fundamentally solve the problems of easy erosion of slopes and easy secondary degradation after restoration in South China; and fourth, lack of timeliness and adaptability, using fixed plant-microorganism configuration ratios without dynamic adjustment based on the needs of different restoration stages, resulting in low restoration precision.

[0004] In summary, existing general remediation technologies cannot solve the specific pain points of tailings dam remediation in South China, and suffer from serious homogenization, insufficient innovation, and poor long-term effectiveness. Developing a multi-level synergistic remediation method of microorganisms and native plants that is adapted to the climate of South China, has strong erosion resistance, high remediation efficiency, and long-term stability has become an urgent technical challenge to be solved in this field. Summary of the Invention

[0005] To address the above-mentioned technical problems, this invention discloses a method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants. By constructing a localized hierarchical synergistic and dynamically regulated restoration system, it achieves rapid and stable ecological restoration of tailings ponds, while reducing restoration costs and improving the durability of restoration effects. This provides exclusive technical support for the ecological restoration of tailings ponds in South China and solves the problems of existing restoration methods being unsuitable for the harsh climate, low vegetation survival rate, long restoration cycle, and insufficient erosion resistance in South China.

[0006] The technical solution adopted by this invention is as follows:

[0007] An ecological restoration method for tailings ponds in South China based on multi-level synergy between microorganisms and native plants includes the following steps:

[0008] Step S1: Select native pioneer plants that are tolerant of poor soil and erosion from the surrounding area; select native plants that have strong nitrogen fixation and soil stabilization capabilities; and select native landscape plants that have both ecological functions and landscape effects.

[0009] Specific functional strains were isolated and screened from the rhizosphere soil of plants around the local tailings dam. The specific functional strains include nitrogen-fixing bacteria, phosphate-solubilizing bacteria and stress-resistant microorganisms. A mixture of local functional strains was prepared.

[0010] Step S2: Sow native pioneer plants on the slope of the tailings dam, spray with a mixture of native functional bacteria, and water regularly to keep the soil moist, so that the native pioneer plants can germinate and grow smoothly, quickly cover the slope, and build a pioneer layer.

[0011] Step S3: After the vegetation coverage of the pioneer layer reaches more than 70%, transplant native seedlings of local dominant plants, and at the same time supplement the spray with nitrogen-fixing bacteria mixture once every 3 months to enhance soil fertility, promote the growth of dominant plants, and build the dominant layer.

[0012] Step S4: After the vegetation community in steps S2 and S3 has stabilized, transplant native landscape plant seedlings, regularly remove weeds to ensure normal vegetation growth, and construct a landscape layer. This landscape layer optimizes the vegetation landscape while maintaining the dynamic balance between microorganisms and plants, without the need for additional spraying of inoculants.

[0013] The vanguard layer, the cluster layer, and the landscape layer form a multi-level, three-dimensional, collaborative protection structure.

[0014] This technical solution, based on the hot and rainy climate characteristics of South China, selects native South China pioneer plants that are tolerant of poor soil and erosion as the pioneer layer, selects native South China native plants with strong nitrogen-fixing and soil-stabilizing capabilities as the building layer, and selects native South China native landscape plants that combine ecological functions and landscape effects as the landscape layer, forming a three-tiered vegetation community structure. Specific functional microorganisms, including nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and stress-resistant microorganisms, are targeted for isolation and screening from the rhizosphere soil of plants surrounding tailings ponds in South China. These specific functional microorganisms are coupled with the three-tiered plant configuration system described in step one to form a triple-coupled synergistic restoration mechanism of microbial activation, plant enrichment, and soil improvement. Through the three-tiered plant configuration and the synergistic effect of microorganisms and plants, an erosion-resistant pioneer layer, a nitrogen-fixing functional layer, and a root stabilization layer are sequentially constructed from the surface to the deep layers of the tailings pond slope, forming a three-layered three-dimensional synergistic protection system to achieve efficient and long-term ecological restoration of the tailings pond slope.

[0015] As a further improvement of the present invention, the concentration ratio of nitrogen-fixing bacteria, phosphate-solubilizing bacteria and stress-resistant microorganisms in the mixed solution of native functional bacteria is 2:1:1.

[0016] As a further improvement of the present invention, in step S1, screening native pioneer plants that are tolerant to poor soil and erosion from the local area includes: quantitatively measuring the cumulative germination rate, survival rate and main and lateral root development characteristics of candidate plants in the local area under the combined pollution of lead and zinc, and screening out species with a cumulative germination rate >80% and the ability to take root quickly.

[0017] As a further improvement of the present invention, the screening of native plants with strong nitrogen fixation and soil fixation capabilities includes: using the TTC method to determine the root activity of native plants under heavy metal stress, and combining the DTPA extraction method to verify the fixation and passivation effect of their root exudates on available heavy metals in the soil, and selecting native plants with a bioaccumulation coefficient BCF>50.

[0018] As a further improvement of the present invention, the screening of native landscape plants that combine ecological functions and landscape effects includes: long-term monitoring of the photosynthetic parameters, chlorophyll fluorescence characteristics and cell membrane permeability of candidate plants under heavy metal background, and evaluating their stable growth ability and landscape maintenance potential under low maintenance conditions. The specific quantitative screening criteria are: after continuous growth under heavy metal stress for 90 days, the relative chlorophyll content (SPAD value) of candidate plants decreases by less than 15%, and the cell membrane permeability increases by less than 20%; plants with stable photosynthetic performance and low cell membrane damage under long-term heavy metal stress, and which combine ecological stability and landscape effects, are screened out.

[0019] As a further improvement of the present invention, the targeted isolation and screening of specific functional bacterial strains from the rhizosphere soil of plants around the local tailings dam includes: firstly, using selective LB plates containing high concentrations of Pb / Zn to perform preliminary screening of bacterial strains in the rhizosphere soil of plants around the local tailings dam, selecting stress-resistant strains with a minimum inhibitory concentration (MIC) > 1000 mg / L; subsequently, by measuring the IAA and ACC deaminase activities, siderophore production, and phosphorus solubilization capabilities of the strains, targeted quantitative screening of local nitrogen-fixing and phosphorus-solubilizing bacteria with highly efficient growth-promoting and activation functions is performed. The specific targeted quantitative screening criteria are: under standard culture conditions, the IAA (indoleacetic acid) content secreted by the selected strains is > 30 mg / L, the specific activity of its ACC deaminase is > 150 nmol / (mg·h), the siderophore activity index (SU units) is > 40%, and the phosphorus solubilization amount (available phosphorus release) in the available phosphorus determination is > 80 mg / L. Only strains that meet the above four quantitative indicators can be identified as having efficient growth-promoting and activation functions. Finally, through pot inoculation comparison experiments, the changes in heavy metal content and biomass in the aboveground parts of plants were accurately measured using ICP-MS. In the end, the enrichment-promoting synergistic strains that can significantly improve the enrichment efficiency of heavy metals were screened out. The quantitative definition criteria are: compared with the control group that only planted the corresponding plants but did not inoculate with the specific functional strain, the total enrichment of heavy metals (Pb / Zn) in the aboveground parts of the plants after inoculation increased by more than 30%, and the activation efficiency (i.e., the proportion of extractable heavy metals converted into available forms) of the soil in the colonization area was greater than 25%.

[0020] As a further improvement of the present invention, the pioneer layer native plants include Cynodon dactylon and / or Paspalum notatum, the building layer native plants include Amorpha fruticosa and / or Acacia spp., and the landscape layer native plants include Nerium oleander and / or Duranta erecta.

[0021] As a further improvement of the present invention, the nitrogen-fixing bacteria is Azotobacter chroococcum; the phosphate-solubilizing bacteria is Bacillus megaterium; and the stress-resistant microorganism is heavy metal-resistant Bacillus.

[0022] As a further improvement of the present invention, the spatial layout of the multi-level three-dimensional collaborative protection structure is as follows: the whole adopts a staggered dense planting of contour furrows and ridges parallel to the mountain slope, with a row spacing of 50cm-100cm; the top 0-5cm is the anti-erosion pioneer layer, which is formed by the interweaving of the fibrous root system of the pioneer plants and the 5cm thick soil-fixing and passivating matrix to form a net-like composite consolidation layer; the middle layer 5-30cm is the nitrogen-fixing functional layer, which is composed of the lateral roots of the community-building layer plants and the functional microbial community artificially sprayed in situ; the deep layer 30cm and above is the root stabilization layer, which is formed by the vertical taproot system of the community-building layer and landscape layer plants penetrating into the deep layer of tailings sand to form biological anchors.

[0023] As a further improvement of the present invention, the main components of the soil stabilization and passivation matrix include biochar and lime; the transplanting spacing of the seedlings in the establishment layer is 1.5m×1.5m, and the transplanting hole depth is 40cm.

[0024] As a further improvement of the present invention, the method for ecological restoration of tailings ponds in South China based on multi-level synergy of microorganisms and native plants also includes phased restoration according to a functional-time dynamic coupling configuration strategy; the functional-time dynamic coupling configuration strategy includes the initial restoration stage, the middle restoration stage, and the later restoration stage, and dynamically adjusts the configuration ratio and application method of plants and microorganisms according to the core needs of different stages of the initial, middle and later stages of tailings pond restoration.

[0025] Furthermore, the initial remediation phase aims at rapid establishment and erosion resistance of the pioneer layer. Specific operations during this initial phase include: within 0-1 month, taking into account the concentrated rainy season in South China, implementing micro-topographic contour furrowing and laying a 5-10cm passivating substrate; within 1-2 months, using a 10% concentration... 8 Seeds of pioneer plants were coated with a bacterial solution of CFU / mL. A mixed bacterial solution of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and stress-resistant microorganisms in a concentration ratio of 2:1:1 was sprayed. Within 2-6 months, 0.1%–0.5% polyacrylamide water-retaining agent was applied. Irrigation was controlled by a soil moisture sensor to regulate water and nutrients. The colonization rate of the strains and soil enzyme activity were monitored using qPCR technology.

[0026] Furthermore, the mid-term remediation was triggered by the pioneer layer vegetation coverage reaching 70%. Based on GIS and Kriging interpolation, the remediation area was divided into lightly, moderately, and heavily lead-polluted patches and differentiated control was implemented. In the lightly polluted area, the Pb concentration was <500mg / kg, the ratio of dominant layer plants to pioneer plants was 2:1, the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms was adjusted to 4:1:1, dominant layer seedlings were transplanted at 1.5m×1.5m intervals, and bacterial solution was precisely irrigated into the rhizosphere, replenished every 3 months. In moderately polluted areas with Pb concentrations of 500-1000 mg / kg, the ratio of pioneer plants to community-building plants is 1:1, and the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms is adjusted to 3:1:1, using a patch-based intercropping pattern. In heavily polluted areas with Pb concentrations ≥1000 mg / kg, the ratio of pioneer plants to community-building plants is 1:2, and the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms is adjusted to 2:1:2, with an emphasis on increasing the proportion of stress-resistant microorganisms.

[0027] Furthermore, in the later stages of restoration, when the canopy closure of the dominant plant layer reaches 0.3 or higher, native plants for the landscape layer are interplanted in the gaps under the forest. The NDVI vegetation health index is monitored using a drone equipped with a multispectral camera. When the NDVI is below 0.25 for three consecutive weeks, targeted replanting, pruning, and weeding are carried out. Artificial supplementation of exogenous microorganisms is stopped, and the native microbial community is maintained by relying on plant root secretions to form a self-sustaining ecological cycle.

[0028] The above technical solution adopts a function-time dynamic coupling configuration strategy, and is implemented in stages according to the initial, middle and late stages of remediation. It combines the differentiated regulation of plant ratio, microbial compatibility and operation and maintenance methods based on the degree of soil pollution, and optimizes the soil structure through the synergistic effect of microorganisms and plants, which significantly reduces the saturated hydraulic conductivity of the slope soil and resists runoff erosion.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] First, it has strong regional adaptability: it uses native plants and in-situ screened functional microorganisms from South China, which are perfectly adapted to the climate and soil characteristics of South China, which are hot, rainy and infertile. The survival rate of plants and microorganisms is high, and no complicated artificial maintenance is required, which reduces the cost of restoration.

[0031] Second, the restoration efficiency has been significantly improved: the vegetation coverage rate has reached over 95%, the vegetation survival rate has increased by over 50%, and the ecological restoration cycle has been shortened by over 30%, achieving rapid ecological restoration of tailings ponds and accelerating the process of land resource reuse.

[0032] Third, it has outstanding erosion resistance: through the synergistic regulation of plants and microorganisms, the saturated hydraulic conductivity of the slope soil is reduced by 90%, which significantly slows down the slope runoff velocity and effectively solves the problem of slope runoff erosion. It solves the problem of slope runoff erosion caused by heavy rainfall in South China from both micro and macro levels, and eliminates the risk of soil erosion and slope landslides.

[0033] Fourth, the restoration effect is long-lasting and stable: It constructs a benign ecological cycle integrating microorganisms, plants and soil, forming a stable vegetation community and a multi-level synergistic protection system. After restoration, it is not easy to experience secondary degradation, thus improving the durability of the restoration effect.

[0034] Fifth, it is more practical and easier to promote: the technical solution is simple and easy to operate, and the required plants and microorganisms are all native species in South China, which are easy to obtain and low in cost. It can be widely used in the ecological restoration of various tailings ponds in South China, filling the gap in regional restoration technology in South China. Detailed Implementation

[0035] The preferred embodiments of the present invention will be described in further detail below.

[0036] An ecological restoration method for tailings ponds in South China based on multi-level synergy between microorganisms and native plants is proposed. This method abandons existing generalized and singular restoration approaches, constructing a multi-level plant configuration system adapted to the hot and rainy climate of South China. Combining native functional microorganisms and pollution-tolerant native plants, a triple-coupled synergistic restoration mechanism of microbial activation, plant enrichment, and soil improvement is formed. A functional-time-dependent dynamic coupling configuration strategy is proposed, ultimately forming a multi-level synergistic protection system to achieve efficient and long-term ecological restoration of tailings pond slopes. The specific implementation steps are as follows:

[0037] (1) Construction of a multi-level plant configuration system

[0038] This paper proposes a three-tiered plant configuration method: pioneer-group-landscape. This method differs from existing techniques that rely on single plants or simple plant combinations. Based on the unique climate and soil characteristics of South China—high temperature, abundant rainfall, poor soil, and easy erosion—it specifically selects pollution-tolerant native plants from South China to construct a layered and targeted vegetation system. The functions and plant selections at each level are unique to the South China region, as detailed below:

[0039] Pioneer Layer: Through extreme stress germination phenological screening, native pioneer plants of South China (such as Bermuda grass and Bahia grass) that are tolerant of poor soil, erosion-resistant, and fast-growing are selected. Specifically, in lead-zinc contaminated soil, the cumulative germination rate (screening standard >80%), survival rate, and main and lateral root development characteristics of candidate plants are quantitatively measured to select species that can quickly establish roots. Unlike the selection of general pioneer plants in existing technologies, this configuration is specifically adapted to the characteristics of South China—high temperature, high rainfall, and easily eroded slopes. Its main function is to quickly cover the slope, reduce slope runoff velocity, minimize soil erosion, stabilize the topsoil, lay the foundation for subsequent vegetation growth, and address the unique challenges of initial slope exposure and easy erosion in South China.

[0040] Pioneer Layer: Through physiological evaluation and targeted screening of rhizosphere soil-fixing functions, native plants of South China (such as Amorpha fruticosa and Acacia confusa) with strong nitrogen-fixing, soil-fixing, and heavy metal-stabilizing capabilities were selected. Specifically, the TTC method was used to determine the root activity of plants under heavy metal stress, and the DTPA extraction method was used to verify the fixation and passivation effects of root exudates (such as organic acids) on available heavy metals in the soil (Bioaccumulation Factor BCF > 50). Unlike existing empirical methods that use generic nitrogen-fixing plants, the selected plants form a specific pairing with pioneer layer plants. Through the integration of deep root systems with the soil and native microorganisms, soil fertility is gradually improved, a stable plant community structure is constructed, and the durability of the vegetation community is enhanced, addressing the regional pain points of soil infertility and the difficulty of long-term vegetation survival in South China.

[0041] Landscape Layer: Through long-term stress resistance and physiological response measurements, native plants of South China (such as oleander and yellow plum) with both ecological functions and landscape effects were screened. Specifically, the photosynthetic parameters (measured with a SPAD instrument), chlorophyll fluorescence characteristics, and cell membrane permeability of candidate plants under heavy metal stress were monitored over a long period to assess their stable growth capacity and landscape maintenance potential under low-maintenance conditions. The specific quantitative screening criteria were: after 90 days of continuous growth under heavy metal stress, the relative chlorophyll content of candidate plants decreased by less than 15%, and the increase in cell membrane permeability was less than 20%. Unlike existing technologies that prioritize restoration over landscape or blindly introduce general landscape plants, this approach optimizes the vegetation landscape in the later stages of restoration, achieving the dual goals of ecological restoration and landscape beautification, enhancing the ecological and landscape value of the restored area, and filling the technological gap in the ecological and landscape synergy of tailings dam restoration in South China.

[0042] (2) Construction of a microbial-plant synergistic repair system

[0043] Using a technical approach of in-situ isolation, functional screening, and synergistic verification, specific functional bacterial strains (including nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and stress-resistant microorganisms) were targeted for isolation and screening from the rhizosphere soil of plants surrounding local tailings ponds in South China. Specifically, the screening process began with initial screening using selective LB plates containing high concentrations of Pb / Zn, and stress-resistant strains with extreme tolerance thresholds (e.g., MIC > 1000 mg / L) were precisely identified through minimum inhibition concentration (MIC) experiments. Subsequently, by measuring the IAA (auxin) production, ACC deaminase activity, siderophore production, and phosphorus solubilization capacity of the strains, local nitrogen-fixing and phosphate-solubilizing bacteria with highly efficient growth-promoting and activation functions were quantitatively screened. The quantitative screening criteria were: under standard culture conditions, the screened strains secreted IAA content > 30 mg / L, had ACC deaminase specific activity > 150 nmol / (mg·h), siderophore activity index (SU units) > 40%, and in the available phosphorus determination, their phosphorus solubilization (available phosphorus release) > 80 mg / L. Only strains meeting the above four quantitative indicators can be considered to possess highly efficient growth-promoting and activation functions. Finally, through a pot inoculation comparison experiment, ICP-MS was used to accurately measure the changes in heavy metal content and biomass in the aboveground parts of the plants, ultimately screening out accumulation-promoting synergistic strains that significantly enhance heavy metal accumulation efficiency. The quantitative definition standard is: compared to the control group that only planted the corresponding plants but did not inoculate with this specific functional strain, the total accumulation of heavy metals Pb / Zn per plant in the aboveground parts of the inoculated plants increased by more than 30%, and the activation efficiency of available heavy metals in the soil within the colonization area was greater than 25%. This rigorous local geological screening process differs from the blind introduction of exotic or general strains in existing technologies. It constructs a triple-coupled synergistic remediation system of microbial activation, plant accumulation, and soil improvement with the aforementioned native pollution-tolerant plants of South China. The three form a benign synergistic mechanism, as detailed below:

[0044] Microbial activation: Native functional strains can activate insoluble nutrients (such as phosphorus and potassium) in tailings pond soil, decompose harmful substances such as heavy metals in soil, improve soil microenvironment, provide suitable conditions for plant root growth, solve the problem of soil infertility and high pollutant content, and are different from the defects of existing technologies where strains are not targeted and have a single activation function.

[0045] Plant enrichment: Native plants absorb pollutants such as heavy metals in the soil through their developed root systems, thereby enriching and transforming pollutants and reducing the degree of soil pollution. At the same time, the decay of plant leaves and roots can increase soil organic matter, further optimizing the soil environment and forming a unique synergy with native microorganisms, which is different from the problem of no regional compatibility between plants and microorganisms in existing technologies.

[0046] Soil improvement: Microorganisms and plant roots work together to improve soil aggregate structure, enhance soil water and fertilizer retention capacity, and form a virtuous ecological cycle of microbial activation of nutrients - plant absorption and utilization - soil fertility improvement, providing a guarantee for the long-term stable growth of vegetation. This is different from the design of existing soil improvement technologies that are disconnected from the synergy between microorganisms and plants.

[0047] (3) Formation of a multi-level collaborative protection system

[0048] Through the aforementioned three-tiered plant configuration and the synergistic effect of microorganisms and plants, a three-layered, three-dimensional, synergistic protection system is ultimately formed: an anti-erosion pioneer layer, a nitrogen-fixing functional layer, and a root-stabilizing layer. Each layer is highly coupled in terms of spatial arrangement, structural characteristics within and between layers, and operational processes, comprehensively improving the restoration effect and slope stability, unlike existing technologies that use a single protective layer and disconnect protection from restoration. The specific three-dimensional layout structure, system protection, and hierarchical synergistic mechanism are described below:

[0049] The three-dimensional layout and structural features of the three-layer space: In terms of planar arrangement, the contour furrows are arranged in a staggered and dense planting pattern that follows the contour of the mountain, with a row spacing of 50cm-100cm. The top layer (0–5cm) is the erosion-resistant vanguard layer, which is formed by the interweaving of the horizontal fibrous root system of herbaceous plants (Bermudagrass, Bahiagrass) and the 5cm thick layer of soil-stabilizing and passivating matrix evenly laid on the outermost layer, forming a highly shear-resistant network composite consolidation layer that specifically intercepts storm runoff; the middle layer (5–30cm) is the nitrogen-fixing functional layer, which is jointly composed of the horizontal radial lateral roots of the dominant woody plants (Amorpha fruticosa, Acacia confusa) and the functional microbial community (nitrogen-fixing bacteria, phosphate-solubilizing bacteria, etc.) of seed coating and in-situ irrigation, which are interwoven and locked together with the downward fibrous roots of herbaceous plants; the deep layer (30–40cm and above) is the root stabilization layer, which uses the vertical taproot system of woody plants (Acacia confusa, Oleander) to drive into the deep unsaturated tailings sand through a mini-digging machine, longitudinally penetrating the potential shear slip surface, forming a highly tensile natural "biological anchor".

[0050] The process of cross-level hydrological and fertility synergy between multiple levels: Operationally, firstly, trenches are dug at equal elevations on the slope and passivated substrate is laid, then 10... 8 Seeds coated with CFU / mL activated bacterial solution in the pioneer layer achieve rapid herbaceous germination, synergistically mitigating surface erosion and promoting underground colonization within the initial layer. In the mid-term, once vegetation cover reaches the target, seedlings in the establishment layer are transplanted into 40cm deep holes at 1.5m x 1.5m intervals. The native microbial community in the middle nitrogen-fixing functional layer continuously activates and improves the soil, transporting nutrients upwards to nourish herbs and downwards to nourish the stabilizing layer. Shrub lateral roots and herbaceous fibrous roots intertwine across layers, achieving inter-level synergy of "fertilizer production in the middle layer and soil stabilization across layers" in the mid-term. In the later stage, the deep stabilizing layer provides anchorage for the main body, the middle functional layer sustains nutrients and passivates heavy metals, and the surface barrier curbs tailings dust and naturally replenishes organic matter; the three layers are interconnected and self-sustaining.

[0051] (4) Function-Time Coupling Configuration Strategy

[0052] A function-time dynamic coupling configuration strategy is adopted to dynamically adjust the configuration ratio and types of plants and microorganisms according to the core needs of different stages of tailings dam remediation, so as to achieve precise remediation. It is specifically adapted to the climate and soil change characteristics of different remediation stages in South China, as follows:

[0053] Initial Remediation Phase (1–6 Months): This phase, tailored to the concentrated rainy season and high rainfall intensity in South China, employs a continuous and meticulous process involving micro-topography preparation, microbial agent coating and spraying, and integrated intelligent water and fertilizer management. This rapidly addresses the issues of exposed slopes and susceptibility to erosion, improving the soil microenvironment from both physical and biochemical perspectives. Firstly, within 0–1 month, contour furrow planting technology is used to optimize the micro-topography based on the slope, initially reducing surface runoff velocity to minimize initial soil erosion. Simultaneously, a 5–10 cm thick passivation substrate (mainly composed of biochar and lime) is precisely laid on the leveled furrow surface, or a 5 cm thick passivation substrate layer is used as a dust-suppressing protective layer combining straw and non-woven fabric. This rapidly neutralizes the extreme pH value of the surface soil and adsorbs free heavy metals, providing a safe micro-bed for pioneer plant seeds to germinate. During the synergistic application phase lasting 1–2 months, a high-concentration activated microbial agent seed coating technology is used before sowing. This involves pre-attaching selected native activated microorganisms (nitrogen-fixing bacteria, phosphate-solubilizing bacteria, stress-resistant microorganisms, etc.) to the surface of pioneer plants (such as Bermuda grass and Bahia grass) seeds, with strict control over the concentration of the coating solution to reach 10%. 8 CFU / mL; After evenly sowing in contour furrows, a mixture of native functional bacteria is sprayed in a specific ratio of 2:1:1 (nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and stress-resistant microorganisms) using drones or manual spraying systems to enhance the activation and growth-promoting effect of the local microenvironment. During the 2–6 month water and fertilizer regulation and monitoring stage, considering the high temperature, high humidity, and high evaporation rate in South China, 0.1%–0.5% polyacrylamide (PAM) water-retaining agent is applied simultaneously in the sowing area for dual-effect regulation of drought resistance, water retention, and erosion resistance. This maintains the soil moisture required for seed germination while effectively binding surface tailings particles. At the same time, relying on deployed soil moisture sensors, the irrigation frequency and amount are automatically controlled, and quantitative slow-release fertilizer is precisely applied through drip irrigation systems or drones to achieve integrated water and fertilizer regulation and solve the problem of extreme infertility of tailings sand in the early stage. Throughout the 1–6 month period, a quantitative microenvironment monitoring and dynamic feedback mechanism was implemented. Instead of relying on visual observation, regular sampling and quantitative analysis were conducted. Target genes were dynamically detected using qPCR technology to determine the colonization rate of the strains. At the same time, the activities of key enzymes such as urease and phosphatase in the topsoil were measured to accurately verify and regulate the actual improvement effect of activated microorganisms on soil organic matter metabolism and effective nutrient transformation.

[0054] Mid-term remediation (7–18 months) implementation process and operation: This stage abandons the blind and uniform incremental strategy. Instead, based on the dynamic monitoring data of the Internet of Things and soil sensors in the early stage, and with the vegetation coverage of the pioneer layer reaching more than 70% as the trigger condition, the tailings dam remediation area is dynamically divided into three different levels of contaminated patches using GIS spatial analysis and Kriging interpolation method, and a differentiated control is strictly implemented for each area. For Situation A: Mildly polluted patches (Pb concentration <500mg / kg), where heavy metal stress is relatively low, the core objective is to rapidly improve soil fertility and build a top-level community. Operationally, the planting ratio of nitrogen-fixing plants and pioneer / hyperaccumulating plants in the community layer was significantly increased from the initial low ratio to 2:1. In response to the nitrogen consumption caused by rapid vegetation expansion, the initial ratio of nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, and stress-resistant microorganisms was dynamically adjusted from 2:1:1 to 4:1:1. Seedlings in the community layer were transplanted at fixed points with a spacing of 1.5m × 1.5m. The microbial application method was changed to precise rhizosphere irrigation (50mL per plant), which was replenished every 3 months. For situation B: moderately polluted patches (Pb concentration 500–1000 mg / kg), it is necessary to balance pollutant enrichment and removal with community stabilization and soil fixation. In terms of operation, patch staggered planting is adopted, and the mixed planting ratio of community-building plants and pioneer / hyperaccumulating plants is precisely controlled at 1:1. The microbial compatibility ratio is dynamically adjusted to 3:1:1 to moderately increase the proportion of nitrogen-fixing bacteria. The focus is on interplanting community-building plants in the gaps of sparse pioneer plants, and promoting the interweaving of underground lateral roots between them and pioneer plants through local rhizosphere fertilization and rhizosphere irrigation. For Situation C: Severely polluted patches (Pb concentration ≥ 1000 mg / kg), due to the extremely high soil toxicity in this area, continuous detoxification by hyperaccumulating plants is necessary. Operationally, a relatively conservative strategy is adopted to increase the proportion of dominant plants, setting the ratio of pioneer / hyperaccumulating plants to dominant tolerant plants at 1:2 (i.e., the dominant layer accounts for approximately 66.7%, utilizing its deep root system to provide long-term stress resistance and deep soil stabilization support). Simultaneously, facing immense plant survival pressure, the microbial ratio is dynamically adjusted to 2:1:2 to simultaneously enhance the ratio of nitrogen-fixing and stress-resistant microorganisms, effectively alleviating plant heavy metal stress responses through their continuously secreted ACC deaminase. Through the above differentiated ratios and dynamic adjustments for light, moderate, and severe pollution areas, the mid-term operation achieves precise regulation of fertilization in areas requiring fertilizer and stress resistance in heavily polluted areas. Nitrogen-fixing plants in the dominant layer combine with nitrogen-fixing bacteria in customized proportions under different ratios, continuously increasing the available nitrogen content of the micro-soil and ensuring long-term community succession.

[0055] The implementation process and operation procedures in the later stage of restoration (19 months and above): After the system has completed the rapid coverage and community establishment in the early and middle stages, the core goal in this stage will shift from survival and detoxification to ecological aesthetics, community stability and self-sustainability. A continuous process flow will be adopted, which includes understory space configuration based on canopy closure, AI-driven adaptive dynamic maintenance, and micro-ecological balance with low human intervention, to fill the technical gap of no landscape optimization and dynamic maintenance in the later stage. Firstly, in the configuration optimization operation, when the dominant layer (such as Amorpha fruticosa and Acacia confusa) forms a stable canopy structure and the canopy closure reaches 0.3 or above, shade-tolerant native landscape plants with low heavy metal accumulation (such as Oleander and Prunus cerasifera) are interplanted in the understory gaps or edge areas that have been tested and found to be safe. This configuration makes full use of the physical buffering effect of the dominant layer canopy on summer rainstorms and strong direct sunlight in South China to improve the microclimate, and makes the root system of the landscape layer distributed in the middle and shallow layers complement the deep-rooted dominant layer and the shallow-rooted pioneer layer in a three-dimensional ecological niche. While maximizing the use of soil space, it avoids vicious competition between species and achieves a dual balance between ecological restoration and landscape beautification. Secondly, in dynamic control operations, drones equipped with multispectral cameras are used regularly to scan the entire restoration area to calculate the NDVI vegetation health index. A smart trigger mechanism is established based on a digital twin system: once the NDVI of a local area is detected to be below the health threshold of 0.25 for three consecutive weeks, the system automatically identifies and locks down the vegetation degradation stress area. Subsequently, the system automatically plans replanting areas and recommends the addition of highly tolerant plants, precisely guiding manual or light machinery to carry out targeted weed clearing, diseased branch pruning, or targeted replanting, completely abandoning the traditional inefficient model of blind, comprehensive patrols. Simultaneously, regarding the change in operational methods, the manual application of nitrogen-fixing bacteria or phosphorus-solubilizing bacteria mixtures is explicitly stopped in the later stages. The system relies entirely on the plant root exudates established in the early stages to naturally nourish and stabilize the vast native functional microbial community in the rhizosphere. Through the natural succession of plant leaf fall returning to the roots, root humification, and microbial decomposition, a long-term closed-loop self-sustaining cycle of plant carbon production and microbial nitrogen fixation and phosphorus solubilization is formed. Based on this, for specific old mining demonstration sites, small-scale trial planting of economic crops with safe heavy metal testing was carried out in forest areas with stable landscape and ecology, and the safety of the products was strictly verified. In this way, a long-term maintenance funding model that uses short-term gains to support long-term development was explored, so as to ensure the long-term sustainability of the restoration effect on both economic and ecological levels.

[0056] Plant-Microbe Synergistic Regulation and Hydrological Characteristic Optimization Process: This invention optimizes slope hydrological characteristics through full-process plant-microbe synergistic regulation, significantly reducing the saturated hydraulic conductivity of slope soil and effectively addressing the technical challenge of severe slope runoff erosion in tailings ponds in South China. The specific biochemical and physical synergistic regulation mechanism and in-situ dynamic interaction process are as follows: First, during the targeted nourishment of rhizosphere functional microbiota by plant secretions, the roots of native plants (such as Bermuda grass and Amorpha fruticosa) continuously secrete specific proportions of organic acids (such as citric acid and tartaric acid), carbohydrates, and phenolic substances (such as flavonoids and coumarins) into the soil micro-domain. These secretions, acting as specific carbon sources and signaling molecules, target and nourish the artificially injected specific functional microbiota (such as Bacillus megaterium and Azotobacter chrysoprase) in the rhizosphere soil, promoting rapid and massive colonization and proliferation of functional microbiota within 1 cm of the plant root surface in the rhizosphere micro-domain. Subsequently, a microscopic consolidation process occurs between microbial extracellular polymeric substances (EPS) and mineral sand particles. Stimulated by plant secretions, the colonized microbial community enters a period of vigorous metabolism, secreting large amounts of highly viscous EPS (containing polysaccharides, glycoproteins, and extracellular DNA). These EPS polymers act as natural bio-adhesives at the microscopic level, guiding the transformation of fine tailings sand particles into large-diameter aggregates through chemical bonding and physical encapsulation. This firmly binds loose tailings sand particles around the plant roots, significantly altering the porosity distribution characteristics in a standard normal random field. Simultaneously, at the microscopic scale, inoculated arbuscular mycorrhizal fungi (AMF) spores germinate in the rhizosphere and infect the plant roots. The vast network of fungal hyphae generated by their metabolism extends significantly outward from the root surface to form a dense underground micro-skeleton, further securing the hardened tailings sand particles through physical entanglement and the synergistic effect of the EPS adhesive. On a macroscopic scale, this microscopic mycelial-adhesive structure, deeply integrated with the horizontally densely interwoven fibrous root system of surface herbaceous plants (such as bermudagrass) and the vertically interwoven radial lateral root system and vertical taproot system of mid-to-deep woody plants (such as Amorpha fruticosa and Acacia confusa), together constitutes a multidimensional, crisscrossing, interlocking graded grid structure. Ultimately, this achieves macroscopic regulation of hydrological characteristics and self-sustaining erosion resistance. This macroscopic-microscopic composite three-dimensional grid completely alters the capillary fissure connectivity of the tailings slope, physically blocking some of the interconnected continuous seepage pores, transforming the originally highly permeable, loose tailings sand into a dense structural layer with high shear strength. Spatially, this regulation alters the standard unsaturated seepage flow field of the soil, and macroscopically reduces the saturated hydraulic conductivity of the slope soil by more than 90%, fundamentally slowing down the infiltration rate of rainstorms and the erosion rate of surface runoff on the slope, thus synergistically achieving long-term slope soil and water conservation and degradation prevention.

[0057] The following section provides a detailed explanation of the specific implementation method using a case study of ecological restoration of a non-ferrous metal tailings dam in South China.

[0058] (1) Experimental area: The slope of a non-ferrous metal tailings pond in South China was selected. The soil in this area is barren and has a high content of heavy metals. The average annual rainfall is 1200-2000 mm. It is hot and rainy, and the slope is prone to runoff erosion. The vegetation coverage is less than 30%, which meets the restoration scenario of this invention. This scenario is exclusive to the South China region.

[0059] (2) Screening of native species: Pioneer plants (Bermudagrass, Bahiagrass), community-building plants (Amorpha fruticosa, Acacia confusa), and landscape plants (Oleander, Prunus cerasifera) were screened from the soil around the experimental area. All of them are native pollution-tolerant plants in South China, which is different from the selection of general plants in the existing technology. Nitrogen-fixing bacteria (Azotobacter chrysothelius), phosphate-solubilizing bacteria (Bacillus megaterium), and stress-resistant microorganisms (Bacillus thuringiensis) were screened. All of them are native functional bacteria.

[0060] (3) Implementation steps:

[0061] In the initial stage of restoration (1-6 months): Sow Bermuda grass and Bahia grass seeds evenly on the slope of the tailings dam, and spray a mixture of local functional bacteria (nitrogen-fixing bacteria, phosphorus-solubilizing bacteria and stress-resistant microorganisms in a concentration ratio of 2:1:1) at a rate of 500 ml per square meter. Water regularly to keep the soil moist and ensure that the pioneer plants germinate and grow successfully and quickly cover the slope.

[0062] Mid-stage remediation (7-18 months): Six months after sowing, the measured vegetation coverage of the pioneer layer reached 72% (meeting the triggering condition). Using GIS, the experimental area was divided into lightly, moderately, and heavily polluted patches for differentiated dynamic control.

[0063] In lightly polluted patches (Pb concentration measured at approximately 450 mg / kg, accounting for about 30%): the focus was on rapidly improving community fertility. The ratio of Amorpha fruticosa to pioneer herbaceous plants was adjusted to 2:1, and seedlings were transplanted at a spacing of 1.5m × 1.5m. At the same time, the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms in the sprayed mixed bacterial solution was dynamically adjusted to 4:1:1, and precise rhizosphere irrigation (50 mL per plant) was adopted, with replenishment every 3 months.

[0064] In moderately polluted patches (Pb concentration measured at approximately 800 mg / kg, accounting for about 50%): taking into account both enrichment and soil stabilization, community-building plants and pioneer plants were intercropped in the gaps of the patches at a ratio of 1:1, and the ratio of functional microbial communities was adjusted to 3:1:1 for local rhizosphere fertilization.

[0065] In heavily polluted patches (Pb concentration measured at approximately 1250 mg / kg, accounting for about 20%): Due to the extreme stress on plant survival, the intercropping ratio of pioneer plants to tolerant plants in the building layer was conservatively set at 1:2 (to strengthen deep stress-resistant soil stabilization support); at the same time, the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms in the mixed bacterial solution was urgently adjusted to 2:1:2, so as to significantly alleviate the heavy metal stress response of vegetation in the heavily polluted area by increasing the proportion of stress-resistant microorganisms (which secrete a large amount of ACC deaminase).

[0066] Late restoration stage (19 months and above): After the vegetation community has stabilized, transplant oleander and yellow plum seedlings to optimize the vegetation landscape and maintain the dynamic balance between microorganisms and plants. No additional inoculants are needed; only regular weeding is required to ensure normal vegetation growth.

[0067] Implementation results and comparison with existing technologies: After 24 months of actual application and on-site monitoring, the vegetation coverage rate of the tailings dam test area using the method of this invention remained stable at 96.3%, the final plant survival rate was as high as 88%, the ecological restoration cycle was shortened by 32%, the saturated hydraulic conductivity of the slope soil was reduced by 91%, and the problems of slope erosion and soil loss were fundamentally improved.

[0068] In contrast, if existing conventional tailings remediation technologies (such as the conventional tree and shrub contour digging and mixed planting process disclosed in Chinese patent CN103039150B, or the single alfalfa green manure periodic turning and burying process disclosed in Chinese patent CN104718835A) are implemented under the same high temperature and rainy weather and high concentration of lead and zinc toxicity stress in South China: due to the lack of a surface anti-erosion three-dimensional consolidation layer formed by the interweaving of "herbaceous fibrous roots + passivated matrix", and the lack of a dynamic adaptation mechanism of "microscopic fungal-plant synergy - macroscopic pollution patch zoning differential regulation", according to industry engineering baselines and conventional application technical indicators, the expected comprehensive vegetation survival rate under similar flowing water and highly toxic site conditions is usually difficult to exceed 40% (the engineering experience baseline is generally around 36%), and after experiencing high-intensity runoff erosion during the rainy season, it is very easy to cause secondary degradation of vegetation survival rate and severe erosion of imported soil.

[0069] Based on a comprehensive comparison of engineering application logic and technical indicators, the vegetation survival rate of this invention achieves a significant improvement of approximately 52% compared to the aforementioned representative conventional patented technologies. This quantitative comparative data fully demonstrates the regional adaptability, long-term stability, and significant technological advancement of the multi-level synergistic and dynamic control strategy of this invention in the extreme scenario of tailings ponds in South China.

[0070] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants, characterized in that: Includes the following steps: Step S1: Select native pioneer plants that are tolerant of poor soil and erosion from the surrounding area; select native plants that have strong nitrogen fixation and soil stabilization capabilities; and select native landscape plants that have both ecological functions and landscape effects. Specific functional strains were isolated and screened from the rhizosphere soil of plants around the local tailings dam. The specific functional strains include nitrogen-fixing bacteria, phosphate-solubilizing bacteria and stress-resistant microorganisms. A mixture of local functional strains was prepared. Step S2: Sow native pioneer plants on the slope of the tailings dam, spray with a mixture of native functional bacteria, and water regularly to keep the soil moist, so that the native pioneer plants can germinate and grow smoothly, quickly cover the slope, and build a pioneer layer. Step S3: After the vegetation coverage of the pioneer layer reaches more than 70%, transplant native seedlings of local dominant plants, and at the same time supplement the spray with nitrogen-fixing bacteria mixture once every 3 months to enhance soil fertility, promote the growth of dominant plants, and build the dominant layer. Step S4: After the vegetation community in steps S2 and S3 has stabilized, transplant seedlings of native landscape plants, regularly clear weeds, ensure normal vegetation growth, and construct a landscape layer. The vanguard layer, the cluster layer, and the landscape layer form a multi-level, three-dimensional, collaborative protection structure.

2. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 1, characterized in that: In step S1, screening native pioneer plants that are tolerant of poor soil and erosion from the local area includes: quantitatively measuring the cumulative germination rate, survival rate and main and lateral root development characteristics of candidate plants in the local area under lead-zinc combined pollution soil environment, and screening out species with a cumulative germination rate >80%. The screening of native plants with strong nitrogen fixation and soil fixation capabilities includes: using the TTC method to determine the root activity of native plants under heavy metal stress, and combining the DTPA extraction method to verify the fixation and passivation effect of their root exudates on available heavy metals in the soil, and selecting native plants with a bioaccumulation coefficient BCF>50. The screening of native landscape plants that combine ecological functions and landscape effects includes: monitoring the photosynthetic parameters, chlorophyll fluorescence characteristics, and cell membrane permeability of candidate plants under heavy metal background, and evaluating their stable growth ability and landscape maintenance potential under low maintenance conditions. The specific quantitative screening criteria are: after continuous growth under heavy metal stress for 90 days, the relative chlorophyll content of candidate plants decreases by less than 15%, and the cell membrane permeability increases by less than 20%. The targeted isolation and screening of specific functional bacterial strains from the rhizosphere soil of plants surrounding the local tailings dam includes: firstly, using selective LB plates containing high concentrations of Pb / Zn to initially screen bacterial strains in the rhizosphere soil of plants surrounding the local tailings dam, selecting stress-resistant strains with a minimum inhibitory concentration (MIC) > 1000 mg / L; subsequently, by measuring the IAA and ACC deaminase activities, siderophore production, and phosphorus solubilization capabilities of the strains, targeted quantitative screening of local nitrogen-fixing and phosphorus-solubilizing bacteria with highly efficient growth-promoting and activation functions is conducted. The targeted quantitative screening criteria are: under standard culture conditions, the screened strains secrete IAA content > 30 mg / L, have ACC deaminase specific activity > 150 nmol / (mg·h), siderophore activity index > 40%, and have phosphorus solubilization capacity > 80 mg / L in the available phosphorus determination. Only strains that meet the above four quantitative indicators can be identified as having efficient growth-promoting and activation functions. Finally, through pot inoculation comparison experiments, the changes in heavy metal content and biomass in the aboveground parts of plants were accurately measured using ICP-MS. In the end, the enrichment-promoting synergistic strains that can significantly improve the enrichment efficiency of heavy metals were screened out. The quantitative definition criteria are: compared with the control group that only planted the corresponding plants but did not inoculate with the specific functional strain, the total enrichment of heavy metals Pb / Zn in the aboveground parts of the plants after inoculation increased by more than 30%, and the activation efficiency of available heavy metals in the soil in the colonization area was greater than 25%.

3. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 2, characterized in that: The pioneer layer native plants include Bermuda grass and / or Bahia grass; the community layer native plants include Amorpha fruticosa and / or Acacia confusa; the landscape layer native plants include oleander and / or Prunus cerasifera.

4. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 2, characterized in that: The nitrogen-fixing bacteria are *Azotobacter chrysozoans*; the phosphate-solubilizing bacteria are *Bacillus megaterium*; and the stress-resistant microorganisms are heavy metal-resistant *Bacillus*.

5. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 1, characterized in that: The spatial layout of the multi-level three-dimensional collaborative protection structure is as follows: the overall structure adopts a staggered and dense planting of contour furrows and ridges parallel to the mountain slope, with a row spacing of 50cm-100cm; the top 0-5cm layer is the anti-erosion pioneer layer, which is a network-like composite consolidation layer formed by the interweaving of the fibrous root system of pioneer plants and the soil-fixing and passivating matrix; the middle layer 5-30cm is the nitrogen-fixing functional layer, which is composed of the lateral roots of the community-building layer plants and the functional microbial community artificially sprayed in situ; the deep layer 30cm and above is the root stabilization layer, which is formed by the vertical taproot system of the community-building layer and landscape layer plants penetrating into the deep layer of tailings sand to form biological anchors.

6. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 1, characterized in that: It also includes implementing repairs in stages according to a function-time dynamic coupling configuration strategy, which includes the initial repair phase, the middle repair phase, and the later repair phase. The specific procedures for the initial remediation phase are as follows: Within 0-1 month, taking into account the concentrated rainy season in South China, micro-topography contour furrowing is carried out, and a 5-10cm passivation substrate is laid; within 1-2 months, a 10% concentration is used... 8 Seeds of pioneer plants were coated with a bacterial solution of CFU / mL. A mixed bacterial solution of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and stress-resistant microorganisms in a concentration ratio of 2:1:1 was sprayed. Within 2-6 months, 0.1%–0.5% polyacrylamide water-retaining agent was applied. Irrigation was controlled by a soil moisture sensor to regulate water and nutrients. The colonization rate of the strains and soil enzyme activity were monitored using qPCR technology.

7. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 6, characterized in that: The mid-term remediation was triggered by a 70% coverage rate of the pioneer layer vegetation. Based on GIS and Kriging interpolation, the remediation area was divided into lightly, moderately, and heavily lead-polluted patches and differentiated control measures were implemented. In lightly polluted areas, the Pb concentration was <500 mg / kg, the ratio of dominant layer plants to pioneer plants was 2:1, and the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms was adjusted to 4:1:

1. Dosage layer seedlings were transplanted at 1.5m × 1.5m intervals, and the rhizosphere was precisely irrigated with bacterial solution, which was replenished every 3 months. In moderately polluted areas with Pb concentrations of 500-1000 mg / kg, the ratio of pioneer plants to community-building plants is 1:1, and the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms is adjusted to 3:1:1, using a patch-based intercropping pattern. In heavily polluted areas with Pb concentrations ≥1000 mg / kg, the ratio of pioneer plants to community-building plants is 1:2, and the concentration ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: stress-resistant microorganisms is adjusted to 2:1:2, with an emphasis on increasing the proportion of stress-resistant microorganisms.

8. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 7, characterized in that: In the later stage of restoration, when the canopy closure of the dominant plant layer reaches 0.3 or above, native plants for the landscape layer are interplanted in the gaps under the forest. The NDVI vegetation health index is monitored by using a drone equipped with a multispectral camera. When the NDVI is below 0.25 for three consecutive weeks, targeted replanting, pruning and weeding are carried out. Stop artificially supplementing exogenous microorganisms and rely on plant root secretions to maintain the local microbial community, forming a self-sustaining ecological cycle.

9. The method for ecological restoration of tailings ponds in South China based on multi-level synergy between microorganisms and native plants according to claim 1, characterized in that: The concentration ratio of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and stress-resistant microorganisms in the mixed solution of native functional bacteria is 2:1:1.