A method for soil ecological function recovery and evaluation based on mine wasteland

Abstract

The present application relates to the technical field of mine ecological restoration and soil environment evaluation, and more particularly to a soil ecological function restoration and evaluation method based on mine wasteland, comprising the following steps: step S1: constructing a mine wasteland soil ecological function baseline database, including grid sampling and detection of the soil in the area to be restored, obtaining initial detection data of physicochemical property indexes, physical structure indexes, pollution indexes, microbial indexes and biological activity indexes, and setting recovery target thresholds for four types of functional groups accordingly; the present application deeply integrates the recovery measures and the evaluation process, and constructs an integrated closed-loop system of recovery, evaluation, feedback and regulation, and the evaluation result is no longer only used for final acceptance, but also used for real-time guidance of scheme adjustment in the recovery process, solving the fundamental problem of mutual separation of recovery and evaluation in the traditional technology, and significantly improving the pertinence and effectiveness of the restoration.

Description

Technical Field

[0001] This invention relates to the field of mine ecological restoration and soil environmental assessment technology, and in particular to a method for restoring and evaluating the soil ecological function of abandoned mine sites. Background Technology

[0002] Mining activities cause large-scale land damage and degradation of soil ecological functions. Research shows that coal gangue is one of the largest industrial solid wastes emitted by coal mines in my country, with cumulative emissions exceeding 7 billion tons. Existing technologies for the restoration and evaluation of soil ecological functions in mine waste sites can be mainly categorized as follows:

[0003] Soil improvement and substrate reconstruction technologies. Examples include soil reconstruction technologies that use weathered coal gangue mixed with topsoil to construct planting layers and fly ash to construct waterproof layers; "waste-to-waste" technologies that use humus soil screened from municipal solid waste landfills to remediate acidic mines; and BS active soil ecological restoration technology, which promotes the integration of sprayed substrates with rock strata through high-fiber, high-aggregate structure active soil substrates.

[0004] Vegetation restoration technologies include methods for zoning vegetation in abandoned coal mine areas that integrate soil and water conservation with biodiversity enhancement, achieving precise ecological zoning through comprehensive utilization of multi-source environmental data; vegetation restoration methods for abandoned mining areas based on community succession patterns, acquiring data through remote sensing and sensor networks and using intelligent models to zonally and phasedly allocate species; and plant-microbe joint remediation technologies.

[0005] Evaluation methods are a category of technologies. Existing evaluation methods mostly employ remote sensing image analysis, such as methods based on wavelet decomposition to calculate texture features and vegetation cover change indices; methods based on fuzzy hierarchical analysis and the IRMO algorithm to determine the weights of evaluation indicators; methods based on the Xgboost model and recurrent neural network algorithm for evaluation; and evaluation methods based on extension models.

[0006] However, existing technologies have the following common drawbacks:

[0007] First, the recovery methods and evaluation methods are separated. Existing technologies treat "recovery" and "evaluation" as two independent stages: the recovery project is implemented first, and the evaluation is carried out afterward. The evaluation results are only output after the entire project is completed, which cannot provide real-time guidance for adjusting the plan during the recovery process. The essential function of evaluation, "feedback regulation," has not been effectively realized.

[0008] Second, the evaluation subjects are singular and outdated. Existing evaluations mostly adopt single or end-of-period assessments in the form of engineering acceptance, relying on time series analysis of remote sensing data. They cannot reflect the dynamic evolution process of soil ecological function restoration, nor can they discover the synergistic and mutually exclusive relationships between various functional groups during the restoration process.

[0009] Third, there is a lack of dimensions for evaluating soil ecological functions. Current evaluation indicators mainly focus on conventional indicators such as vegetation cover, soil physicochemical properties, and metal concentration. For soil ecological functions, such as nutrient cycling, water conservation, pollutant reduction, and biological habitat function, a systematic, hierarchical evaluation system is lacking. Therefore, a method for the restoration and evaluation of soil ecological functions in abandoned mining areas is needed to address these issues. Summary of the Invention

[0010] This invention aims to provide a method for the restoration and evaluation of soil ecological function in abandoned mine sites based on multi-subject dynamic collaboration, in order to solve the technical problems of disconnect between restoration and evaluation, single and lagging evaluation subject, and lack of multi-subject collaborative optimization mechanism in the existing technology.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A method for restoring and evaluating the ecological function of soil in abandoned mining areas includes the following steps:

[0013] Step S1: Construct a baseline database of soil ecological functions in abandoned mining sites, including gridded sampling and testing of soil in the area to be restored to obtain initial test data on physicochemical properties, physical structure, pollution, microbial, and biological activity indicators, and set restoration target thresholds for four functional groups based on these data; the four functional groups include nutrient cycling, water conservation, pollutant reduction, and biological habitat.

[0014] Step S2: Implement tiered and graded recovery, simultaneously applying differentiated recovery measures to the four functional groups, including:

[0015] Step S2.1: Apply basic soil conditioner to the nutrient cycling functional group and plant pioneer plants, while simultaneously introducing rhizosphere microbial agents;

[0016] Step S2.2: Construct a soil-biochar composite water-retaining layer for the water conservation functional group and build supporting rainwater collection and infiltration units on the periphery;

[0017] Step S2.3: Apply modified mineral composite materials to the soil in situ to passivate heavy metals for the pollutant reduction functional group;

[0018] Step S2.4: Construct a porous media matrix layer and ecological corridor for the aforementioned biological habitat functional group;

[0019] Step S3: Multi-subject dynamic collaborative evaluation, periodically evaluating each functional group according to the preset monitoring period T, including:

[0020] Step S3.1 Functional group state vector acquisition: Collect the corresponding detection indicators for the four functional groups at each sampling point to generate the state vector of each functional group;

[0021] Step S3.2 Independent Evaluation of Functional Groups: After normalizing the current state vector of each functional group with the corresponding index of the initial baseline in Step S1, and referring to the recovery target threshold set in Step S2, the independent comprehensive recovery index of each functional group is calculated using the efficacy coefficient method. i = 1, 2, 3, 4;

[0022] Step S3.3 Multi-subject collaborative evaluation: The four functional groups are regarded as four collaborative working subjects. The coupling coordination degree model is used to calculate the coordination level between each functional group to obtain the coupling degree C and the functional group coupling coordination degree index S.

[0023] Step S3.4 Multi-agent decision-making level fusion evaluation: Based on the independent comprehensive recovery index calculated in step S3.2 The functional group coupling synergy index S calculated in step S3.3 is used to determine the overall restoration level of the soil ecological function of the mine wasteland according to the preset multi-subject decision-making level fusion rules; the overall restoration level includes complete restoration, basic restoration, partial restoration and abnormal restoration.

[0024] Step S4: Adaptive feedback control. When the judgment result of step S3.4 is partial recovery or abnormal recovery, control instructions are generated according to the deviation of the state vector of each functional group and fed back to the recovery measure module of the corresponding functional group in step S2 to adjust the execution parameters of the recovery measures.

[0025] Step S5: Full-cycle convergence judgment. Repeat steps S3 and S4 for at least three complete monitoring cycles. When the judgment results of steps S3 and S4 for two consecutive monitoring cycles are both complete recovery, and the fluctuation range of the functional group coupling synergy index S is lower than the preset convergence threshold, it is determined that the restoration of soil ecological function of mine wasteland has reached a stable convergence state, the final restoration evaluation report is output and the adaptive feedback control is terminated.

[0026] Preferably, in step S1, the gridded sampling and detection is performed as follows: a grid spacing of 40m×40m is used in flat areas, and the grid spacing is increased to 20m×20m in undulating areas; vertically, each sampling point is sampled in three layers, including surface soil, lower soil and saturated soil, the depth of the surface soil is 0-20cm, and the depth of the lower soil is 20-60cm.

[0027] The physicochemical properties include pH value, organic matter content, total nitrogen content, available phosphorus content, available potassium content, cation exchange capacity, and conductivity.

[0028] The physical structure parameters include bulk density, total porosity, aggregate stability, and saturated hydraulic conductivity;

[0029] The pollution indicators include the total amount and available form of heavy metals;

[0030] The microbial indicators include microbial biomass carbon, microbial biomass nitrogen, and soil respiration intensity.

[0031] The bioactivity indicators include urease activity, sucrase activity, phosphatase activity, and catalase activity.

[0032] Preferably, in step S3.1, the state vectors of the four functional groups respectively include:

[0033] The state vector of the nutrient cycling functional group It includes organic matter content, effective nitrogen, phosphorus and potassium content, microbial biomass carbon, and urease activity;

[0034] The state vector of the water conservation functional group This includes soil moisture content, saturated hydraulic conductivity, and field capacity.

[0035] The state vector of the pollutant reduction functional group Includes the content of available heavy metals, pH value, and conductivity value;

[0036] The state vector of the biological habitat functional group It includes the microbial diversity index, earthworm number, and root biomass.

[0037] Preferably, in step S3.3, the calculation formula for the coupling coordination degree model is:

[0038] Coupling ,

[0039] Functional Group Coupling Synergy Index ,

[0040] in That is, the average value of the independent comprehensive recovery index of the four functional groups;

[0041] In step S3.4, the multi-agent decision-level fusion rule is as follows:

[0042] When all If S is greater than or equal to the first threshold and S is greater than or equal to the second threshold, it is considered a complete recovery.

[0043] When all When S is greater than or equal to the third threshold and S is greater than or equal to the fourth threshold, it is considered to have basically recovered.

[0044] When any When S < the third threshold or S < the fourth threshold, it is determined to be partially recovered;

[0045] When any <Fifth threshold, or any When a decrease occurs compared to the previous monitoring period and the decrease exceeds the preset decrease threshold, it is judged as an abnormal recovery.

[0046] Wherein, the first threshold is 0.85-0.95, the second threshold is 0.80-0.90, the third threshold is 0.65-0.75, the fourth threshold is 0.60-0.70, the fifth threshold is 0.35-0.45, and the preset decrease threshold is 10%-20%.

[0047] Preferably, in step S2.1, the basic soil conditioner includes well-rotted organic fertilizer and lime, the pioneer plant includes Koelreuteria paniculata, and the rhizosphere microbial agent includes a mixed bacterial solution of Bacillus subtilis and Bacillus mucilaginosus.

[0048] In step S2.2, the soil-biochar composite water-retaining layer is constructed by laying a biochar layer under the improved soil layer. The biochar is wheat straw biochar, which is obtained by pyrolyzing wheat straw at 450-550℃ under oxygen-limited conditions. The biochar layer is 3-8cm thick. The rainwater collection and infiltration unit includes at least one micro rainwater collection pond built at a lower elevation and at least one underground infiltration pipe connected to it. The outlet end of the underground infiltration pipe is connected to the improved soil layer.

[0049] In step S2.3, the modified mineral composite material is a composite of sodium bentonite and diatomaceous earth, which is prepared by calcination activation and carboxymethyl cellulose surface modification treatment, and the application amount is 1%-5% of the soil weight;

[0050] In step S2.4, the porous media matrix layer is formed by drilling holes in the improved soil layer and filling them with a mixture of decomposed organic matter. The ecological corridor includes a layer of dead branches and fallen leaves laid on the ground surface, with a thickness of 8-15 cm.

[0051] Preferably, the modified mineral composite material is prepared as follows: sodium-based bentonite is used as the matrix, with a cation exchange capacity (CEC) ≥ 80 meq / 100g and a blue absorption capacity ≥ 30g / 100g, and is uniformly mixed with diatomaceous earth at a mass ratio of (3-5):1; the mixed material is calcined and activated at 450-500℃ for 1-3 hours, with a heating rate of 5-10℃ / min; the calcined mixed powder is dispersed in deionized water to prepare a suspension with a solid-liquid ratio of 1:(8-12); carboxymethyl cellulose is added for surface modification, with the amount of carboxymethyl cellulose added being 3%-8% of the bentonite mass; the mixture is continuously stirred and reacted at 60-80℃ for 3-5 hours; after filtration, it is dried and ground through a 150-250 mesh sieve.

[0052] The preparation method of the wheat straw biochar is as follows: the wheat straw is naturally air-dried to a moisture content of ≤12%, heated to 480-520℃ at a heating rate of 15-25℃ / min under a nitrogen protective atmosphere, kept at the temperature for 30-90 minutes, and cooled to room temperature under a nitrogen atmosphere.

[0053] The rhizosphere microbial agent comprises a mixed bacterial suspension of *Pristridium megaterium* and *Bacillus cereus*, with a concentration ≥1×10^8 CFU / mL. The preparation method of the bacterial suspension is as follows: the strain preserved in glycerol tubes is streaked onto LB solid plates and activated by incubation at 28-37℃ for 20-28 hours; single colonies are picked and inoculated into LB liquid medium and cultured with shaking at 28-37℃ and 150-200 r / min for 40-60 hours until the stationary phase, with a viable count ≥1×10^8 CFU / mL; the cultured bacterial suspension is diluted with distilled water at a volume ratio of (0.5-2):1 to obtain the application bacterial suspension.

[0054] Preferably, in step S3.2, the specific calculation method of the efficacy coefficient method is as follows: determine the upper and lower limits of the satisfaction value for each evaluation index, normalize each index of each functional group, and distinguish between positive and negative indicators.

[0055] For positive indicators, the normalized score ;

[0056] For the inverse indicator, the normalized score ;

[0057] in Let j be the measured value of the j-th indicator of the i-th functional group. and These are the lower and upper limits of the recovery target threshold set for this indicator in S2, respectively;

[0058] Then, the weighted summation method was used to calculate the independent comprehensive recovery index of each functional group. ,in Let be the weight coefficient of the j-th indicator, satisfying =1, and the weighting coefficient is determined using the entropy weighting method.

[0059] Preferably, in step S4, the control instructions include: increasing the density of ecological pores, supplementing the spraying of microbial inoculum, starting or adjusting the irrigation flow of the rainwater collection and infiltration unit, applying compound fertilizer, and adding at least one of humic acid to the irrigation water.

[0060] Preferably, the preset monitoring period The timeframe is 25-45 days; the preset convergence threshold is 5%-10%.

[0061] When the S3.4 determination result for two consecutive monitoring cycles is complete recovery, and the fluctuation range of the functional group coupling synergy index S is lower than the preset convergence threshold, the recovery is determined to have reached a stable convergence state.

[0062] Preferably, the method further includes a comparison and verification step of setting a blank control group between step S2 and step S3, wherein the blank control group is:

[0063] In the area to be restored, select a block that is adjacent to the implementation area and has no significant difference in initial soil conditions. Only implement the restoration measures in step S2, without implementing the multi-agent dynamic collaborative evaluation in step S3 and the adaptive feedback control in step S4. This is used to compare and verify the restoration cycle reduction rate and material saving rate of this method.

[0064] This invention has at least the following beneficial effects:

[0065] 1. This invention deeply integrates restoration measures with the evaluation process, constructing an integrated closed-loop system of restoration, evaluation, feedback, and control. The evaluation results are no longer only used for end-of-term acceptance, but also guide the adjustment of the plan in real time during the restoration process. This solves the fundamental problem of the separation between restoration and evaluation in traditional technologies, and significantly improves the pertinence and effectiveness of the restoration.

[0066] 2. This invention introduces the concept of multi-stakeholder collaboration in the ecological restoration evaluation of abandoned mining sites, decomposes soil ecological functions into four independent functional groups, evaluates their restoration degree separately, and uses a coupling coordination degree model to quantify the synergy level between functional groups. This can accurately identify functional group mismatch problems in the restoration process and provide a scientific basis for targeted regulation.

[0067] 3. This invention applies differentiated restoration measures to four functional groups, with each measure implemented in parallel and evolving synergistically. It simulates the mechanism of independent operation and mutual coupling of functional modules in a natural ecosystem. The supporting adaptive feedback control mechanism can automatically generate control instructions based on real-time evaluation results, enabling local intervention for some problems and avoiding comprehensive rework adjustments. Attached Figure Description

[0068] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0069] Figure 1 This is an overall flowchart of a method for restoring and evaluating the soil ecological function of abandoned mining sites according to the present invention.

[0070] Figure 2 This is a mapping table showing the relationship between the recovery measures of each functional group and the state vector of the functional group in this invention;

[0071] Figure 3 This is a summary table of the independent comprehensive recovery index and the functional group coupling synergy index for each monitoring period of this invention. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0073] Reference Figure 1-3 ; Example 1;

[0074] This study focuses on an abandoned site of a polymetallic sulfide mine in southern my country. Located in a humid subtropical monsoon climate zone, the mine receives an average annual rainfall of approximately 1580 mm. The terrain is predominantly low hills with slopes ranging from 8° to 25°. Lead and zinc mining has a history of over 30 years, and the tailings pond and waste rock dump cover a combined area of ​​approximately 5 hectares. The soil is red soil, with virtually no surface vegetation, severe soil acidification (pH 3.8), and significant soil erosion. The average total Cd content is 3.2 mg / kg, with a usable amount of 0.47 mg / kg; the average total Pb content is 178 mg / kg, with a usable amount of 3.2 mg / kg; the organic matter content is only 6.2 g / kg; and the microbial biomass carbon is 28 mg / kg. This embodiment selects a contiguous 5-hectare area downstream of the tailings pond within the aforementioned abandoned site for implementation.

[0075] Step S1: Initial state diagnosis;

[0076] Within the 5-hectare implementation area of ​​this embodiment, the sampling points were selected in accordance with the "Technical Specification for Soil Environmental Monitoring" (HJ / T166-2004) and the "Technical Specification for Soil Environmental Investigation of Industrial and Mining Waste Land Reclamation".

[0077] Preliminary reconnaissance identified three key areas of concern: downstream of the tailings dam overflow outlet, at the foot of the waste rock dump slope, and in the low-lying catchment area. Sampling points were densely distributed in each key area and its downstream region. Three untouched mining sites were selected 2 km outside the mining area as background control points. In gentle slope areas (slope < 8°), the grid spacing was 40m × 40m; in areas with slopes of 8°–25°, the grid spacing was increased to 20m × 20m. A total of 125 sampling points were established (including the 3 background control points).

[0078] Vertically, each sampling point was collected from three layers: topsoil (0-20cm), subsoil (20-60cm), and saturated soil. The depth division of the topsoil and subsoil layers was determined based on the thickness of the backfill soil layer (0-50cm) in this area: topsoil 0-20cm, subsoil 20-60cm; saturated soil was sampled below the groundwater level. An additional sample was collected from the transition zone between the backfill soil layer and the undisturbed soil layer. After each soil sample was quartered, it was sealed in clean polyethylene bags and transported to the laboratory under refrigeration.

[0079] Detection indicators and methods: pH value was determined using the electrode method (water-to-soil ratio 2.5:1); organic matter content was determined using the potassium dichromate oxidation-external heating method; total nitrogen content was determined using the Kjeldahl method; available phosphorus content was determined using the sodium bicarbonate extraction-molybdenum antimony spectrophotometric method; available potassium content was determined using the ammonium acetate extraction-flame photometric method; cation exchange capacity was determined using the ammonium acetate centrifugal exchange method; electrical conductivity was determined using the conductivity meter method. Bulk density was determined using the ring cutter method; total porosity was calculated from bulk density and specific gravity; aggregate stability was determined using the wet sieving method; saturated hydraulic conductivity was determined using the constant head method. Total heavy metal content was determined using the aqua regia-perchloric acid digestion-atomic absorption spectrophotometric method; available content was determined using the DTPA extraction-atomic absorption spectrophotometric method; microbial biomass carbon and nitrogen were determined using the chloroform fumigation extraction-potassium dichromate oxidation method; soil respiration intensity was determined using the alkaline absorption-titration method. Urease activity was determined by the indophenol blue colorimetric method (based on the amount of NH3-N released after 24 hours); sucrase activity was determined by the dinitrosalicylic acid colorimetric method; phosphatase activity was determined by the disodium phenyl phosphate colorimetric method; and catalase activity was determined by potassium permanganate titration.

[0080] The initial test results are summarized above and entered into the database to construct the initial baseline. Target thresholds for the recovery of four functional groups are set: Nutrient cycling functional group: organic matter content ≥20g / kg, available phosphorus ≥15mg / kg, available potassium ≥80mg / kg, urease activity ≥0.8mgNH3-N / (g·24h); Water conservation functional group: field capacity ≥28%, saturated hydraulic conductivity ≥0.8cm / min; Pollutant reduction functional group: Cd available form ≤0.10mg / kg, Pb available form ≤0.8mg / kg; Biological habitat functional group: Shannon diversity index ≥2.5, earthworm density ≥20 individuals / m².

[0081] Step S2: Implement a tiered and graded recovery process;

[0082] The area to be implemented was leveled, and surface debris and gravel were removed. A rotary tiller was used to deeply till and loosen the soil layer from 0-30cm. Well-rotted organic fertilizer (mainly cow manure, composted for over 60 days) was applied at a rate of 3 t / ha; lime (CaO ≥ 85%, fineness 200 mesh) was applied at a rate of 1.5 t / ha. After the organic fertilizer and lime were applied, they were thoroughly mixed a second time using a rotary tiller.

[0083] Plant pioneer plants 7-10 days after soil improvement (until soil pH stabilizes). Plant the Koelreuteria paniculata in pits in the improved soil layer, with a spacing of 4m x 4m, a pit diameter of 40cm, and a pit depth of 40cm. Use 1-year-old seedlings, 50-80cm tall. Apply 200g of phosphate fertilizer (superphosphate, P2O5 ≥ 16%) as base fertilizer to each pit, then backfill with improved soil, compacting it in layers, and water thoroughly to settle the roots.

[0084] Microbial inoculation was carried out on the 3rd day after planting. Using the rhizosphere injection method, holes were evenly drilled around the root system of each Koelreuteria paniculata tree (15-20 cm deep, 6 holes / tree), and a mixed bacterial solution of manganese-resistant growth-promoting bacteria was injected. The bacterial strains were a mixture of *Pristridium megaterium* and *Bacillus cereus*, at a concentration of 1×10⁻⁶. 8 CFU / mL, 0.5L per plant, bacterial culture was prepared using LB medium (10g / L tryptone, 5g / L yeast extract, 10g / L NaCl), and cultured at 30℃ with shaking for 48 hours (180r / min). Field inoculation was carried out after confirming viable cell count.

[0085] The restoration measures for the water conservation function group and the nutrient cycling function group are implemented simultaneously. After the foundation leveling and deep tilling are completed, a soil layer with a depth of 35-40cm is excavated and a 5cm thick layer of wheat straw biochar is laid.

[0086] Biochar preparation process: Wheat straw is naturally air-dried to a moisture content ≤10%, then pyrolyzed and carbonized at 500℃ under limited oxygen conditions, with a heating rate of 15-25℃ / min and a holding time of 60 minutes. It is then cooled to room temperature under a nitrogen atmosphere. The resulting biochar has a specific surface area ≥150m² / g, pH 8.5-9.5, and pore size 2-50nm. After uniform spreading, the biochar is leveled with a grader and compacted with a light roller (compaction degree approximately 85%). Improved soil (30cm thick) is backfilled on top of the biochar layer and compacted in layers. Studies have confirmed that biochar from wheat straw pyrolyzed at 500℃ can fix up to 55.38% carbon, resulting in a final moisture content in acidic soils that is 132.3% higher than in soils without biochar.

[0087] Three miniature rainwater collection ponds, each with a volume of 10m³, will be constructed at a low-lying site. These ponds will be equipped with HDPE membranes for waterproofing and will be accompanied by drainage ditches. The drainage ditches will be 30cm wide, 20cm deep, and have a slope of 1%-3% to guide the surrounding runoff into the collection ponds. The outlet of each collection pond will be connected to an underground infiltration pipe (DN110 PVC perforated pipe, 8mm diameter, 15cm hole spacing), buried at a depth of 40-50cm, and connected to the improved soil layer above the biochar layer. The rainwater collection ponds will collect and store surface runoff during the rainy season and, during the dry season, the rainwater will be evenly infiltrated into the improved soil layer in a slow-release manner through the infiltration pipes.

[0088] Preparation of modified mineral composite materials: Sodium-based bentonite was selected as the matrix (cation exchange capacity CEC≥80meq / 100g, blue adsorption capacity≥30g / 100g), and mixed with diatomaceous earth at a mass ratio of 4:1. The bentonite was activated by high-temperature calcination at 450-500℃ for 2 hours (heating rate 5-10℃ / min, oxygen-limited calcination in a muffle furnace). The calcined mixed powder was dispersed in deionized water to prepare a suspension (solid-liquid ratio 1:10). Carboxymethyl cellulose (5% of the bentonite mass) was added for surface modification. The reaction was continuously stirred at 70℃ for 4 hours. After filtration, it was dried at 105℃ and ground through a 200-mesh sieve. Natural bentonite has the limitation of low adsorption capacity. After modification and composite processing, the specific surface area is significantly increased, the interlayer spacing is expanded, and the adsorption capacity of heavy metals is greatly improved.

[0089] After shallow soil loosening, the composite material is evenly spread on the surface at 2.0% of the soil weight, and then deeply tilled (0-40cm) using a rotary tiller to ensure thorough mixing with the contaminated soil. The composite material utilizes the increased specific surface area (from approximately 30m² / g to 80-100m² / g) and interlayer negative electrostatic adsorption of heavy metal cations through bentonite calcination. Simultaneously, surface modification of carboxymethyl cellulose introduces carboxyl (-COOH) and hydroxyl (-OH) functional groups, which coordinate and chelate with heavy metal ions, forming stable metal-organic complexes. The pollutant reduction measures and the biochar layer form a spatial synergy: the biochar layer, located at a depth of 30-35cm, serves as both a water reservoir and a heavy metal ion interception barrier, preventing pollutants from migrating downwards.

[0090] After the restoration measures for other functional groups are completed and the soil structure is stable, a porous media matrix layer will be constructed. A hollow spiral drilling device with a drill rod diameter of 8cm will be used to drill holes in the improved soil layer at a density of 4 holes / m², with a hole diameter of 8cm and a hole depth of 50cm. The holes will penetrate the backfilled improved soil layer down to the original soil layer. All the drilled soil will be discharged from the holes. Each reserved ecological channel will be filled with a mixture of decomposed organic matter to a height of 5cm below the ground surface. The volume ratio of the organic matter mixture is decomposed cow manure: rice husk: vermiculite = 3:1:1. The hole openings will be covered with reserved topsoil. The ecological channels will penetrate a 30-35cm deep biochar layer in the profile depth direction, forming a continuous vertical channel that runs through the improved layer, biochar layer and original soil layer.

[0091] A 10cm thick layer of fallen leaves and branches was laid on the surface. The mulch material consisted of a mixture of fallen leaves collected from the surrounding mining area, mainly from broad-leaved trees of the Fagaceae and Lauraceae families. After being exposed to sunlight for 3 days to kill insect eggs, the mulch was laid on the surface of the implementation area, covering 100% of the area. The mulch layer inhibited surface moisture evaporation, reducing evaporation by about 40-60%, and reduced soil erosion by more than 70%. It also provided an organic matter source for surface microorganisms and decomposers. The underlying ecological channels provided migration channels and refuge spaces for soil animals.

[0092] The four functional group restoration measures form a hierarchical and synergistic structure in space: vertically, it consists of a surface layer of dead leaves and branches → a 0-30cm improved soil layer (nutrient cycling measures, ecological pore entrance) → a 30-35cm biochar water retention layer (water conservation measures, pollutant reduction barrier) → a 35-60cm lower treatment zone (pollutant reduction measures, ecological pore extension); horizontally, the Koelreuteria paniculata plants provide support for nutrient cycling, microbial agents promote nutrient transformation in the rhizosphere, ecological pores connect all layers, and the rainwater collection and infiltration system forms a cross-water management network with the biochar layer.

[0093] Step S3: Multi-subject dynamic collaborative evaluation;

[0094] A monitoring cycle of T=30 days is used, starting from the date of resumption of implementation. At the end of each monitoring cycle, sampling is conducted according to the same grid layout rule as S1 (40m×40m grid in flat areas and 20m×20m grid in undulating terrain areas). Soil samples are collected from 0-30cm depth at each sampling point, excluding biochar layers, to ensure consistent sampling depth for all indicators.

[0095] Composition and detection methods of state vectors for each functional group: Nutrient cycling functional group V_N includes organic matter content (g / kg, potassium dichromate oxidation-external heating method), available phosphorus content (mg / kg, sodium bicarbonate extraction-molybdenum antimony spectrophotometric method), available potassium content (mg / kg, ammonium acetate extraction-flame photometric method), microbial biomass carbon (mg / kg, chloroform fumigation extraction-potassium dichromate oxidation method), and urease activity (mgNH3-N / (g·24h, indophenol blue colorimetric method). Water conservation functional group V_W includes soil moisture content (%, dry weighing method), saturated hydraulic conductivity (cm / min, constant head method undisturbed soil column determination), and field capacity (%, ring cutter method). Pollutant reduction functional group... This includes the bioavailable Cd and Pb content (mg / kg, DTPA extraction-atomic absorption spectrophotometry), pH value (electrode method, water-to-soil ratio 2.5:1), EC value (μS / cm, conductivity meter method), and the biodiversity functional group V_B, which includes the Shannon index of microbial diversity (dilution plate counting method and 16S rRNA gene amplicon high-throughput sequencing). Earthworm count (number of earthworms / m², manual separation method), root biomass (g / m², root extraction method).

[0096] Data normalization: Positive indicators adopt ;

[0097] Inverse indicators are adopted .

[0098] For the first The first functional group The measured values ​​of the indicators and These represent the lower and upper limits of the target recovery threshold for this indicator, where the upper limit is the background value or maximum value, and the lower limit is the initial value or minimum value. Functional Group Independent Comprehensive Recovery Index , =1, weight The entropy weight method is used to determine the weights, which are automatically assigned based on the degree of dispersion of each indicator during the recovery process. The greater the degree of dispersion, the greater the amount of information, and the higher the weight assigned.

[0099] Taking the first monitoring cycle as an example, the nutrient cycling functional group had organic matter of 8.5 g / kg, available phosphorus of 12 mg / kg, available potassium of 65 mg / kg, microbial biomass carbon of 45 mg / kg, and urease activity of 0.24 mg NH3-N / (g·24h). The normalized scores were 0.166, 0.35, 0.312, 0.133, and 0.176, respectively. The entropy weight method determined the weights to be 0.25, 0.15, 0.15, 0.25, and 0.20, respectively, and R1 = 0.214 was calculated. Similarly, R2 = 0.182, R3 = 0.236, and R4 = 0.153.

[0100] Functional group coupling synergy index calculation: Coupling degree Overall development level of the system Coupling and Coordination Index For the first period, R1=0.214, R2=0.182, R3=0.236, R4=0.153, (R1×R2×R3×R4)^(1 / 4)≈0.194, the sum of the denominators is 0.785, C≈0.988, T≈0.196, S≈0.440.

[0101] Multi-subject decision-making level fusion rule determination level:

[0102] all A value ≥0.90 and S≥0.85 are considered fully recovered.

[0103] all A value ≥0.70 and S≥0.65 are considered as basic recovery;

[0104] any A value <0.70 or S <0.65 is considered a partial recovery.

[0105] any If R_i is less than 0.40 or any R_i decreases by more than 15% relative to the previous cycle, it is considered an abnormal recovery. In the first cycle, R1=0.214<0.70, so it is considered a partial recovery.

[0106] Step S4: Adaptive feedback control;

[0107] When the result of step S3.4 is partial recovery or abnormal recovery, the system analyzes the deviation of the state vector of each functional group, generates control instructions, and the technical personnel execute them on site.

[0108] In the first cycle, R4 = 0.153 is the lowest, and R2 and R1 are also relatively low. Generating instructions:

[0109] 1. Increase the density of ecological channels to 8 channels / m², and drill additional holes between existing channels (implemented on days 32-35).

[0110] 2. Replenish the surface cover with a mixture of Bacillus subtilis and bacterial solution (concentration 1×10⁻⁶). 8 (CFU / mL, dosage 0.5 L / m²) to accelerate organic matter decomposition and microbial community construction. Preparation of Bacillus subtilis mixed solution: A glycerol-preserved strain (China General Microbiological Culture Collection Center CGMCC No. 1.3359) was streaked onto LB agar plates (tryptone 10 g / L, yeast extract 5 g / L, NaCl 10 g / L, agar powder 15 g / L, pH 7.0) and incubated at 30°C for 24 hours for activation. Single colonies were picked and inoculated into LB liquid medium and cultured at 30°C with shaking at 180 rpm for 48 hours until the stationary phase, with a viable count ≥ 1 × 10⁻⁶. 8 CFU / mL; dilute 1:1 with distilled water and refrigerate at 4°C for no more than 7 days.

[0111] 3. Turn on the rainwater collection tank and infiltration unit, and start infiltration irrigation from the 36th day, continuously replenishing water to the improved soil layer at a flow rate of 0.5-1.0 L / min·m;

[0112] 4. Apply phosphorus and potassium compound fertilizer (12-12-17) to the root zone of the goldenrain tree, 150g per tree, at a depth of 20-25cm in the hole; add a trace amount of humic acid to the irrigation water (5kg humic acid mixed with 1000L of water) to supplement microbial nutrition.

[0113] Step S5: Full-cycle convergence judgment;

[0114] Repeat steps S3-S4 for at least three complete monitoring cycles. Evaluation results for each cycle:

[0115] On day 60, R1=0.58, R2=0.54, R3=0.72, R4=0.49, and S=0.68, indicating partial recovery.

[0116] On day 90, R1=0.76, R2=0.71, R3=0.84, R4=0.67, and S=0.79, indicating basic recovery.

[0117] On day 120, R1=0.86, R2=0.82, R3=0.89, R4=0.81, and S=0.87, indicating basic recovery.

[0118] On day 150, R1=0.92, R2=0.88, R3=0.91, R4=0.87, and S=0.91, indicating complete recovery.

[0119] On day 180, R1=0.93, R2=0.90, R3=0.92, R4=0.89, and S=0.92, indicating a complete recovery.

[0120] The S-value changes from 0.91 to 0.92, with a fluctuation range of (0.92-0.91) / 0.91×100%≈1.1%, which is less than the convergence threshold of 5%. After two consecutive cycles, it is determined that the recovery is complete and the recovery has reached stable convergence. The adaptive feedback control is terminated, and the final recovery evaluation report is output.

[0121] Final test results: Soil pH increased from 3.8 to 6.8; organic matter increased from 6.2 g / kg to 24.3 g / kg; Cd available form decreased from 0.47 mg / kg to 0.09 mg / kg, a decrease of 80.9%; Pb available form decreased from 3.2 mg / kg to 0.7 mg / kg, a decrease of 78.1%; microbial biomass carbon increased from 28 mg / kg to 156 mg / kg; vegetation cover increased from almost 0 to 91%; earthworm density increased from approximately 0 earthworms / m² to approximately 24 earthworms / m² (≥20 earthworms / m² target). Example 2;

[0122] The study focused on an abandoned spoil heap at an open-pit coal mine in northern my country. Located in a temperate semi-arid continental monsoon climate zone, the area receives an average annual rainfall of approximately 400 mm, with evaporation rates 3-4 times higher than precipitation. The spoil heap was formed from mining overburden, primarily composed of weathered sandstone and mudstone. The soil contains over 70% sand and less than 5 g / kg of organic matter, exhibiting extremely poor water and fertilizer retention capacity. The study area covers 8 hectares, characterized by gently sloping platforms with gradients ranging from 5° to 15°.

[0123] Key differences and adjustments from Example 1:

[0124] I. Water Conservation Functional Group: The biochar layer thickness is increased from 5cm to 8cm to enhance water storage capacity; in addition to the underground infiltration system, a drip irrigation network (buried depth 15-20cm, dripper spacing 50cm, dripper flow rate 1.5L / h) is added, using slightly saline water (mineralization ≤2.5g / L) as the water source, equipped with a fully automatic backwashing disc filter (filtration accuracy 120 mesh) and pressure-compensating drippers. The drip irrigation system operates in parallel with the rainwater collection tank. During the rainy season, the rainwater collection tank is the main water source, and during the dry season, irrigation well water or slightly saline water is used for supplementation, increasing irrigation efficiency by about 40% and reducing water consumption per unit area by about 30%.

[0125] II. Nutrient Cycling Functional Groups; For alkaline soils in northern regions, lime application was reduced from 1.5 t / ha to 0.5 t / ha, and ferrous sulfate (FeSO4·7H2O, 300 kg / ha) was supplemented to adjust pH and supplement iron. Pioneer plants were changed to a mixed sowing pattern of sea buckthorn and alfalfa: sea buckthorn was planted at a spacing of 3m × 4m, and alfalfa was sown between rows at a rate of 15 kg / ha. Sea buckthorn fixes nitrogen through symbiotic root nodules, and its deep root system (the taproot can reach a depth of 2-3m) can penetrate the biochar layer to access water in the lower layers. Alfalfa quickly covers the soil surface to reduce soil erosion. Nitrogen-fixing spirochetes were added to the microbial inoculant to enhance biological nitrogen fixation capacity.

[0126] III. Pollutant Reduction Functional Group: Heavy metal pollution in coal mine spoil heaps is mainly Cr (average value about 180 mg / kg, available form about 0.32 mg / kg) and Cu (about 65 mg / kg, available form about 0.18 mg / kg). The proportion of diatomaceous earth is increased to 50% of the bentonite mass. Modified zeolite is added. The zeolite is acidified with 2 mol / L HCl for 8 hours, washed with water until neutral, dried at 105℃, and ground through a 200-mesh sieve. The composite material application rate is 2.0%, applied in two stages: the first 1.2% at 0-30cm, and the second 0.8% at 30-50cm, forming a two-layer composite barrier.

[0127] IV. Monitoring Period and Convergence Conditions: The growing season for northern plants is approximately 6 months, from May to October. Winter temperatures drop below -20℃, so the monitoring period is adjusted to 40±5 days. Only passive monitoring of environmental parameters is maintained. No active evaluation or feedback control is performed in winter. When the final evaluation result for two consecutive growing seasons is complete recovery, and the fluctuation range of the S value before and after the dormancy period is less than 10%, the recovery is considered to have reached stable convergence.

[0128] After three full-year cycles: soil organic matter increased from an initial 4.8 g / kg to 18.6 g / kg; field water holding capacity increased from 18% to 31%; available Cr decreased from 0.32 mg / kg to 0.08 mg / kg, and available Cu decreased from 0.18 mg / kg to 0.05 mg / kg; the coverage of sea buckthorn and alfalfa reached over 85%; and soil microbial biomass carbon increased from 18 mg / kg to 110 mg / kg. Example 3;

[0129] In the implementation area of ​​Example 1, three adjacent blocks (1 hectare each) with no significant difference in initial soil conditions were selected, and the following treatment methods were set:

[0130] Processing Group A: Implement the complete process according to Example 1, i.e., steps S1-S5.

[0131] Control group B: Only the differentiated recovery measures of S2 were implemented, without the periodic evaluation of S3 and the feedback regulation of S4, and a one-time final evaluation was conducted after 180 days.

[0132] Control group C: The recovery measures were implemented according to S2, and a final evaluation was conducted on day 180 (the evaluation content of S3 was implemented, but the feedback control of S4 was not carried out), which is the traditional "recovery first, evaluation later" model.

[0133] Control group D: Recovery measures were implemented according to S2, and periodic evaluations were conducted according to the same cycle (T=30 days) in S3, but no feedback regulation was performed in S4.

[0134] The comparison metrics for each block on day 180 are as follows:

[0135] Treatment group A took 78 days to reach basic recovery, which was 57 days shorter than control groups B and C, approximately 42%. On day 180, the S-value of treatment group A was 0.92, which was 70.4%, 58.6%, and 29.6% higher than that of B, C, and D, respectively. The R-range was only 0.05, while that of group B was as high as 0.51. The material consumption of treatment group A was approximately 83% of that of groups B and C, and the water use efficiency was approximately 93%, 69%, and 29% higher than that of groups B, C, and D, respectively.

[0136] The comparative data above demonstrates that a complete closed loop of periodic evaluation and adaptive feedback control is the key to achieving coordinated recovery of functional groups, and a single measure cannot achieve the same effect.

[0137] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for restoring and evaluating the ecological function of soil in abandoned mining areas, characterized in that, Includes the following steps: Step S1: Construct a baseline database of soil ecological function in mining waste sites, including gridded sampling and testing of soil in the area to be restored, obtaining initial test data on physicochemical properties, physical structure, pollution, microbial and biological activity indicators, and setting restoration target thresholds for the four functional groups accordingly. The four functional groups include nutrient cycling functional group, water conservation functional group, pollutant reduction functional group and biological habitat functional group; Step S2: Implement tiered and graded recovery, simultaneously applying differentiated recovery measures to the four functional groups, including: Step S2.1: Apply basic soil conditioner to the nutrient cycling functional group and plant pioneer plants, while simultaneously introducing rhizosphere microbial agents; Step S2.2: Construct a soil-biochar composite water-retaining layer for the water conservation functional group and build supporting rainwater collection and infiltration units on the periphery; Step S2.3: Apply modified mineral composite materials to the soil in situ to passivate heavy metals for the pollutant reduction functional group; Step S2.4: Construct a porous media matrix layer and ecological corridor for the aforementioned biological habitat functional group; Step S3: Multi-subject dynamic collaborative evaluation, periodically evaluating each functional group according to the preset monitoring period T, including: Step S3.1 Functional group state vector acquisition: Collect the corresponding detection indicators for the four functional groups at each sampling point to generate the state vector of each functional group; Step S3.2 Independent Evaluation of Functional Groups: After normalizing the current state vector of each functional group with the corresponding index of the initial baseline in Step S1, and referring to the recovery target threshold set in Step S2, the independent comprehensive recovery index of each functional group is calculated using the efficacy coefficient method. i = 1, 2, 3, 4; Step S3.3 Multi-subject collaborative evaluation: The four functional groups are regarded as four collaborative working subjects. The coupling coordination degree model is used to calculate the coordination level between each functional group to obtain the coupling degree C and the functional group coupling coordination degree index S. Step S3.4 Multi-agent decision-making level fusion evaluation: Based on the independent comprehensive recovery index calculated in step S3.2 The functional group coupling synergy index S calculated in step S3.3 is used to determine the overall restoration level of the soil ecological function of the mine wasteland according to the preset multi-subject decision-making level fusion rules; the overall restoration level includes complete restoration, basic restoration, partial restoration and abnormal restoration. Step S4: Adaptive feedback control. When the judgment result of step S3.4 is partial recovery or abnormal recovery, control instructions are generated according to the deviation of the state vector of each functional group and fed back to the recovery measure module of the corresponding functional group in step S2 to adjust the execution parameters of the recovery measures. Step S5: Full-cycle convergence judgment. Repeat steps S3 and S4 for at least three complete monitoring cycles. When the judgment results of steps S3 and S4 for two consecutive monitoring cycles are both complete recovery, and the fluctuation range of the functional group coupling synergy index S is lower than the preset convergence threshold, it is determined that the restoration of soil ecological function of mine wasteland has reached a stable convergence state, the final restoration evaluation report is output and the adaptive feedback control is terminated.

2. The method for soil ecological function restoration and evaluation based on mine wasteland according to claim 1, characterized in that, In step S1, the gridded sampling and detection is performed as follows: a grid spacing of 40m×40m is used in flat areas, and the grid spacing is increased to 20m×20m in undulating areas; vertically, each sampling point is sampled in three layers, including surface soil, lower soil and saturated soil, the depth of the surface soil is 0-20cm, and the depth of the lower soil is 20-60cm. The physicochemical properties include pH value, organic matter content, total nitrogen content, available phosphorus content, available potassium content, cation exchange capacity, and conductivity. The physical structure parameters include bulk density, total porosity, aggregate stability, and saturated hydraulic conductivity; The pollution indicators include the total amount and available form of heavy metals; The microbial indicators include microbial biomass carbon, microbial biomass nitrogen, and soil respiration intensity. The bioactivity indicators include urease activity, sucrase activity, phosphatase activity, and catalase activity.

3. The method for soil ecological function restoration and evaluation based on abandoned mining sites according to claim 1, characterized in that, In step S3.1, the state vectors of the four functional groups respectively include: The state vector of the nutrient cycling functional group It includes organic matter content, effective nitrogen, phosphorus and potassium content, microbial biomass carbon, and urease activity; The state vector of the water conservation functional group This includes soil moisture content, saturated hydraulic conductivity, and field capacity. The state vector of the pollutant reduction functional group Includes the content of available heavy metals, pH value, and conductivity value; The state vector of the biological habitat functional group It includes the microbial diversity index, earthworm number, and root biomass.

4. The method for soil ecological function restoration and evaluation based on abandoned mining sites according to claim 1, characterized in that, In step S3.3, the calculation formula for the coupling coordination degree model is as follows: Coupling , Functional Group Coupling Synergy Index , in That is, the average value of the independent comprehensive recovery index of the four functional groups; In step S3.4, the multi-agent decision-level fusion rule is as follows: When all If S is greater than or equal to the first threshold and S is greater than or equal to the second threshold, it is considered a complete recovery. When all When S is greater than or equal to the third threshold and S is greater than or equal to the fourth threshold, it is considered to have basically recovered. When any When S < the third threshold or S < the fourth threshold, it is determined to be partially recovered; When any <Fifth threshold, or any When a decrease occurs compared to the previous monitoring period and the decrease exceeds the preset decrease threshold, it is judged as an abnormal recovery. Wherein, the first threshold is 0.85-0.95, the second threshold is 0.80-0.90, the third threshold is 0.65-0.75, the fourth threshold is 0.60-0.70, the fifth threshold is 0.35-0.45, and the preset decrease threshold is 10%-20%.

5. The method for soil ecological function restoration and evaluation based on mine wasteland according to claim 1, characterized in that, In step S2.1, the basic soil conditioner includes well-rotted organic fertilizer and lime, the pioneer plant includes goldenrain tree, and the rhizosphere microbial agent includes a mixed bacterial solution of Bacillus subtilis and Bacillus mucilaginosus. In step S2.2, the soil-biochar composite water-retaining layer is constructed by laying a biochar layer under the improved soil layer. The biochar is wheat straw biochar, which is obtained by pyrolyzing wheat straw at 450-550℃ under oxygen-limited conditions. The biochar layer is 3-8cm thick. The rainwater collection and infiltration unit includes at least one micro rainwater collection pond built at a lower elevation and at least one underground infiltration pipe connected to it. The outlet end of the underground infiltration pipe is connected to the improved soil layer. In step S2.3, the modified mineral composite material is a composite of sodium bentonite and diatomaceous earth, which is prepared by calcination activation and carboxymethyl cellulose surface modification treatment, and the application amount is 1%-5% of the soil weight; In step S2.4, the porous media matrix layer is formed by drilling holes in the improved soil layer and filling them with a mixture of decomposed organic matter. The ecological corridor includes a layer of dead branches and fallen leaves laid on the ground surface, with a thickness of 8-15 cm.

6. The method for soil ecological function restoration and evaluation based on mine wasteland according to claim 5, characterized in that, The preparation method of the modified mineral composite material is as follows: sodium-based bentonite is used as the matrix, with a cation exchange capacity (CEC) ≥ 80 meq / 100g and a blue absorption capacity ≥ 30g / 100g. It is uniformly mixed with diatomaceous earth at a mass ratio of (3-5):

1. The mixed material is calcined and activated at 450-500℃ for 1-3 hours, with a heating rate of 5-10℃ / min. The calcined mixed powder is dispersed in deionized water to prepare a suspension with a solid-liquid ratio of 1:(8-12). Carboxymethyl cellulose is added for surface modification, with the amount of carboxymethyl cellulose added being 3%-8% of the bentonite mass. The mixture is continuously stirred and reacted at 60-80℃ for 3-5 hours. After filtration, it is dried and ground through a 150-250 mesh sieve. The preparation method of the wheat straw biochar is as follows: the wheat straw is naturally air-dried to a moisture content of ≤12%, heated to 480-520℃ at a heating rate of 15-25℃ / min under a nitrogen protective atmosphere, kept at the temperature for 30-90 minutes, and cooled to room temperature under a nitrogen atmosphere. The rhizosphere microbial agent comprises a mixed bacterial suspension of *Pristridium megaterium* and *Bacillus cereus*, with a concentration ≥1×10^8 CFU / mL. The preparation method of the bacterial suspension is as follows: the strain preserved in glycerol tubes is streaked onto LB solid plates and activated by incubation at 28-37℃ for 20-28 hours; single colonies are picked and inoculated into LB liquid medium and cultured with shaking at 28-37℃ and 150-200 r / min for 40-60 hours until the stationary phase, with a viable count ≥1×10^8 CFU / mL; the cultured bacterial suspension is diluted with distilled water at a volume ratio of (0.5-2):1 to obtain the application bacterial suspension.

7. The method for soil ecological function restoration and evaluation based on mine wasteland according to claim 1, characterized in that, In step S3.2, the specific calculation method of the efficacy coefficient method is as follows: determine the upper and lower limits of the satisfaction value for each evaluation index, normalize each index of each functional group, and distinguish between positive and negative indicators. For positive indicators, the normalized score ; For the inverse indicator, the normalized score ; in For the first The first functional group The measured values ​​of the indicators and These are the lower and upper limits of the recovery target threshold set in step S2, respectively; Then, the weighted summation method was used to calculate the independent comprehensive recovery index of each functional group. ,in Let be the weight coefficient of the j-th indicator, satisfying =1, and the weighting coefficient is determined using the entropy weighting method.

8. The method for soil ecological function restoration and evaluation based on mine wasteland according to claim 1, characterized in that, In step S4, the control instructions include: increasing the density of ecological pores, supplementing the spraying of microbial inoculum, starting or adjusting the irrigation flow of the rainwater collection and infiltration unit, applying compound fertilizer, and adding at least one of humic acid to the irrigation water.

9. A method for soil ecological function restoration and evaluation based on abandoned mining sites according to claim 1, characterized in that, The preset monitoring period The timeframe is 25-45 days; the preset convergence threshold is 5%-10%. When the determination result of step S3.4 in two consecutive monitoring cycles is complete recovery, and the fluctuation amplitude of the functional group coupling synergy index S is lower than the preset convergence threshold, it is determined that the recovery has reached a stable convergence state.

10. A method for soil ecological function restoration and evaluation based on abandoned mining sites according to claim 1, characterized in that, The method also includes a comparison and verification step between step S2 and step S3, wherein the blank control group is: In the area to be restored, select a block that is adjacent to the implementation area and has no significant difference in initial soil conditions. Only implement the restoration measures in step S2, without implementing the multi-agent dynamic collaborative evaluation in step S3 and the adaptive feedback control in step S4. This is used to compare and verify the restoration cycle reduction rate and material saving rate of this method.

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