Rare earth mine soil seed bank screening and constructing method based on ecological niche complementation

Abstract

The invention discloses a rare earth mine soil seed bank screening and constructing method based on ecological niche complementation, which comprises the following steps: firstly preparing three types of soil matrixes, and selecting candidate plants based on an original community survey result of an unmined rare earth mine; healthy seeds needing to germinate in the candidate plants are selected, and germinated seedlings are obtained after germination culture; planting the germinated seedlings or transplanted seedlings in a three-type soil matrix; measuring the biomass of the plant, and measuring the pH and nutrient content of the soil matrix; screening out resistant plants based on the measured data; based on the ecological niche complementation principle, the screened resistant plants are combined according to herbs, shrubs and vines, and an artificial seed bank is constructed; and sowing the mixture in the improved soil according to a specific density. The screened resistant plants such as caragana microphylla are high in adaptability, the seed bank species structure is reasonable, the vegetation coverage degree after restoration is close to the vegetation coverage level of raw ore, the mine soil restoration efficiency and ecological stability are remarkably improved, and good application prospects are achieved.

Description

Technical Field

[0001] This invention relates to the field of mine ecological restoration technology, and in particular to a method for screening and constructing a rare earth mine soil seed bank based on niche complementarity. Background Technology

[0002] During the leaching process in ion-adsorption rare earth mines, drastic changes occur in the soil's physicochemical properties. Specifically, vegetation is cleared, soil pH decreases significantly, acidification intensifies, and soil nutrients such as TOC and TP are extremely low, resulting in a lack of soil seed bank. This harsh soil environment severely hinders plant growth, leading to vegetation degradation, increased bare land, and ecosystem damage in mining areas.

[0003] Among existing mine soil remediation technologies, phytoremediation is widely used due to its low cost and environmental friendliness, but it has the following shortcomings: First, there is a lack of targeted screening of candidate plants, and the special environment of mine soil acidification and extremely low nutrient content is not fully considered, resulting in low plant survival rates. Second, the natural restoration of abandoned mine sites not only lacks natural seed banks and makes it difficult to form a continuous and stable source of vegetation restoration, but also suffers from problems such as the single species in the seed bank and the failure to combine them according to the principle of ecological niche complementarity, resulting in slow vegetation cover speed and poor stability, requiring the artificial construction of seed banks to form a continuous source of vegetation restoration. Third, soil improvement and plant screening are disconnected, making it difficult to achieve the coordinated promotion of soil environment improvement and vegetation restoration.

[0004] Therefore, there is an urgent need for a targeted and effective method for screening ion-adsorption rare earth mine soil seed banks. Summary of the Invention

[0005] The purpose of this invention is to provide a method for screening and constructing a rare earth mine soil seed bank based on niche complementarity. This method enables the precise screening of acid- and aluminum-resistant plants and, by constructing a well-structured and highly stable artificial seed bank, rapidly increases the vegetation cover of ion-adsorption rare earth mine soils, thereby achieving effective restoration of the soil ecosystem.

[0006] To achieve the above objectives, this invention provides a method for screening and constructing a rare earth mine soil seed bank based on niche complementarity, comprising the following steps: S1. Prepare three types of soil substrates, namely substrate 1, substrate 2 and substrate 3; S2. Based on the survey results of the original community of unmined rare earth mines, herbaceous plants, shrubs and vine seedlings were selected as candidate plants. S3. Select healthy seeds from candidate plants that need to germinate, pre-treat them, and place them in an artificial climate culture chamber for germination culture to obtain germinating seedlings. S4. Plant the germinating seedlings or transplanted seedlings in three types of soil substrates respectively, control the planting density and maintenance conditions, and observe and record the plant growth status and plant height. S5. Determine the aboveground biomass and underground root biomass of the plants, and simultaneously determine the pH, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and aluminum concentration of the three types of soil matrices. S6. Based on the data measured in S5, resistant plants that are tolerant to acidification and poor soil were screened out. S7. Based on the principle of complementary ecological niches, the selected resistant plants are combined into herbaceous, shrub, and vine species to construct an artificial seed bank; S8. Evenly sow the mixed seeds from the artificial seed bank onto the surface of the improved rare earth mine soil, and cover with a thin layer of soil to complete vegetation restoration.

[0007] Preferably, in S1, matrix 1 is rare earth tailings after ammonium sulfate leaching, matrix 2 is rare earth tailings with aluminum content adjusted after aluminum sulfate leaching, and matrix 3 is an improved matrix composed of rare earth tailings with aluminum content adjusted after aluminum sulfate leaching and soil remediation agent. The soil remediation agent is made of red and yellow soil, organic fertilizer and inorganic fertilizer in a ratio of 80~100:10~20:1~5, of which the organic fertilizer is chicken and duck manure, cake fertilizer or biochar.

[0008] Preferably, in S2, candidate plants include foxtail grass, sumac, sea buckthorn, caragana, pigweed, and cassia bipoda to ensure complementary ecological niche differences.

[0009] Preferably, in S3, the candidate plants to be germinated include foxtail grass, sumac, sea buckthorn, caragana, and pigweed. The pretreatment process is as follows: One hundred seeds of each plant were selected and soaked in a 0.5 g / L KMnO4 solution for 24 hours, and rinsed with water at least three times. Wash the petri dishes with sterile water and dry them at high temperature for later use. Line the petri dishes with a layer of moistened absorbent cotton. Prepare 5 petri dishes for each type of plant and sow 20 seeds evenly in each petri dish. They were cultured in an artificial climate incubator with conditions of 25°C, 60% humidity, and 20% light intensity, alternating between day and night every 12 hours. During the germination period, spray an appropriate amount of distilled water on each petri dish daily, observe and record the seed germination status, and obtain germinating seedlings.

[0010] Preferably, S4 is as follows: Germinating seedlings or transplanted seedlings were planted in three types of soil substrates, using 7cm×7cm×7.5cm square flower pots, with 5 pots of each type of plant planted in each type of soil substrate; Among them, the planting density of foxtail grass, caragana, pig manure bean, sumac, sea buckthorn and double-pod cassia is 5 plants per pot; During the plant's growth and maintenance period, water it once every other day, and observe and record the plant's growth status and height.

[0011] Preferably, in S5, the process of measuring the aboveground biomass and underground root biomass of the plant is as follows: Surviving plants were harvested from the three types of soil substrates and placed into resealable bags; After rinsing, the above-ground parts and roots of each plant are separated and placed in a drying oven to dry for 24 hours; The dry weight of the aboveground parts and roots of each plant under three types of soil substrates was determined using an analytical balance to characterize the aboveground biomass and underground root biomass.

[0012] Preferably, in S5, soil samples of each plant planted under the three types of soil substrates are collected, spread evenly on clean paper, spread into a thin layer, and air-dried naturally; an appropriate amount of air-dried soil sample is taken using the quartering method, stones and plant residues are removed, and after being crushed and passed through a 60-mesh sieve, it is placed in a clean self-sealing bag for later use. When measuring soil pH, mix soil with boiled and cooled distilled water at a mass-to-volume ratio of 2:5, shake for 2 minutes, centrifuge at maximum speed for 10 minutes, measure and record the pH value of the supernatant using a pH meter. Total organic carbon (TOC) was determined using a combination of potassium dichromate-sulfuric acid oxidation and ferrous sulfate titration. Both total nitrogen (TN) and total phosphorus (TP) were determined by chemical discontinuity analyzer after digestion with concentrated sulfuric acid and perchloric acid.

[0013] Preferably, in S6, based on the data measured in S5, acid-tolerant and barren-tolerant resistant plants are screened according to plant survival status, biomass accumulation, and adaptability to the soil environment. The screening criteria for resistant plants are as follows: Plants that can survive in substrate 1 or substrate 2 and can increase soil pH, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP).

[0014] Preferably, in S7, the constructed artificial seed bank includes shrubs, herbs, and vines; Shrubs include sisal, indigofera, sage, castor bean, and sumac; herbs include dung bean, vetiver, miscanthus, foxtail grass, ryegrass, dandelion, coreopsis, cosmos, and zinnia; vines include kudzu.

[0015] Therefore, the present invention employs the above-mentioned method for screening and constructing rare earth mine soil seed banks based on niche complementarity, and the beneficial effects are as follows: (1) This invention conducts pot experiments by simulating the soil environment (acidification, low nutrition) after leaching of ion-type rare earth mines, and accurately screens out acid-resistant and barren-resistant plants (such as Caragana korshinskii), thus solving the problem of poor adaptability of existing restoration plants.

[0016] (2) Based on the principle of complementary ecological niches, this invention constructs a composite artificial seed bank containing herbs, shrubs and vines, which has high species diversity and reasonable structure, and improves the stability and anti-interference ability of the vegetation community.

[0017] (3) The soil remediation agent of this invention works synergistically with the seed bank screening, which not only improves the physical and chemical properties of the soil, but also ensures the survival rate of plants. After one month of remediation, the vegetation coverage can reach 70%-80%, which is close to the original vegetation coverage level (80%-90%).

[0018] (4) The method of the present invention is simple to operate, low in cost and highly repeatable. It is applicable to soil vegetation restoration projects in various ion-type rare earth mines and has broad application prospects.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is an overall flowchart of an embodiment of the method for screening and constructing a rare earth mine soil seed bank based on niche complementarity of the present invention; Figure 2 These are examples of different plant seed germination conditions in embodiments of the present invention, which utilizes a method for screening and constructing a rare earth mine soil seed bank based on niche complementarity. Figure 3 This is a schematic diagram illustrating the effects of leaching on soil and the improvement of imported soil in an embodiment of the rare earth mine soil seed bank screening and construction method based on niche complementarity of the present invention. In this diagram, (a) represents the change in soil pH, (b) represents the total organic carbon (TOC) content, (c) represents the total nitrogen (TN) content, (d) represents the total phosphorus (TP) content, and (e) represents the aluminum concentration. Figure 4 This is a schematic diagram of vegetation growth in an embodiment of the method for screening and constructing a rare earth mine soil seed bank based on niche complementarity of the present invention. Figure 5 This is a schematic diagram comparing the plant height of Caragana korshinskii in three soil samples from an embodiment of the present invention's method for screening and constructing a rare earth mine soil seed bank based on niche complementarity. Figure 6 This is a comparison of the biomass of Caragana korshinskii in three groups of soils in an embodiment of the method for screening and constructing a rare earth mine soil seed bank based on niche complementarity of the present invention. (a) represents the aboveground biomass, and (b) represents the underground root biomass. Figure 7These are comparative images of vegetation restoration in rare earth mines before and after restoration, based on the method for screening and constructing rare earth mine soil seed banks with complementary ecological niches, according to an embodiment of the present invention. (a) is a partial image of the rare earth mine ore, (b) is a partial image before restoration, (c) is a partial image after restoration, (d) is an overall image of the rare earth mine ore, (e) is an overall image before restoration, and (f) is an overall image after restoration. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] like Figure 1 As shown, the method for screening and constructing a rare earth mine soil seed bank based on niche complementarity includes the following steps: S1. Prepare three types of soil substrates, namely substrate 1, substrate 2 and substrate 3.

[0024] Matrix 1 is rare earth tailings after leaching with 4% ammonium sulfate for 12 hours; Matrix 2 is rare earth tailings after leaching with 0.02 mol / L aluminum sulfate for 12 hours with adjusted aluminum content; Matrix 3 is an improved matrix consisting of rare earth tailings after leaching with 0.02 mol / L aluminum sulfate for 12 hours with adjusted aluminum content mixed with soil remediation agent.

[0025] According to the plant cultivation techniques of Anyuangangxia, the soil remediation agent is made of strong clayey red and yellow soil, organic fertilizer and inorganic fertilizer in a ratio of 80~100:10~20:1~5. Among them, the organic fertilizer is chicken and duck manure, cake or biochar, etc.

[0026] S2. Based on the survey results of the original communities in unmined rare earth mines, herbaceous, shrub, and vine seedlings with acid tolerance, tolerance to poor soil, and niche differences were selected as candidate plants.

[0027] The candidate plants selected for this invention include foxtail grass, sumac, sea buckthorn, caragana, pigweed, and cassia bipoda, ensuring complementary ecological niche differences. Among them, foxtail grass, sumac, sea buckthorn, caragana, and pigweed are obtained by seed germination, while cassia bipoda and schefflera are obtained by digging up seedlings from Xianxun Garden on the Qianhu Campus of Nanchang University and transplanting them.

[0028] S3. Select healthy seeds from candidate plants that need to germinate, pre-treat them, and place them in an artificial climate culture chamber for germination culture to obtain germinating seedlings.

[0029] In this embodiment, the candidate plants to be germinated include foxtail grass, sumac, sea buckthorn, caragana, and pigweed. The pretreatment process is as follows: One hundred seeds of each plant species were selected and soaked in a 0.5 g / L KMnO4 solution for 24 hours, then rinsed at least three times with clean water. The petri dishes were washed with sterile water and dried at high temperature. A layer of moistened absorbent cotton was placed in each petri dish, with five petri dishes for each plant species. Twenty seeds were evenly sown in each petri dish. The dishes were placed in an artificial climate incubator with the following conditions: temperature 25℃, humidity 60%, light intensity 20%, and day / night cycle alternating every 12 hours. During germination, each petri dish was sprayed daily with an appropriate amount of distilled water. Figure 2 As shown, observe and record the seed germination process to obtain germinating seedlings.

[0030] S4. Plant the germinating seedlings or transplanted seedlings in the three types of soil substrates respectively, control the planting density and maintenance conditions, and observe and record the plant growth status and plant height, specifically: Germinating seedlings or transplanted seedlings were planted in three types of soil substrates, using 7cm×7cm×7.5cm square flower pots, with 5 pots of each type of plant planted in each type of soil substrate.

[0031] Among them, foxtail grass, caragana, pigweed, sumac, sea buckthorn, and cassia bipod were planted at a density of 5 plants per pot. During the plant growth and maintenance period, water was applied once every other day, and the plant growth and height were observed and recorded.

[0032] S5. Determine the aboveground biomass and underground root biomass of the plants, and simultaneously determine the pH, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and aluminum concentration of the three types of soil matrices.

[0033] (1) Biomass: The process of measuring the aboveground biomass and underground root biomass of plants is as follows: Surviving plants were collected from three types of soil substrates and placed in resealable bags. After rinsing, the aboveground parts and roots of each plant were separated and dried in a drying oven for 24 hours. The dry weight of the aboveground parts and roots of each plant under the three soil substrates was then measured using an analytical balance to characterize the aboveground biomass and underground root biomass. A total of 45 samples were collected.

[0034] (2) Soil physicochemical properties: Soil samples of each plant under three different soil substrates were collected, spread evenly on clean paper, and allowed to air dry naturally. A suitable amount of air-dried soil sample was taken using the quartering method, stones and plant debris were removed, and the sample was crushed, passed through a 60-mesh sieve, and then placed in a clean self-sealing bag for later use. A total of 60 samples were collected.

[0035] ① When measuring soil pH, mix soil with boiled and cooled distilled water at a mass-volume ratio of 2:5. In this example, weigh 2g of air-dried soil and place it in a 15mL centrifuge tube. Add 5mL of boiled and cooled distilled water, seal the container, balance the mixture, shake with a shaker for 2 minutes, and then centrifuge at the maximum speed for 10 minutes. Measure and record the pH value of the supernatant using a pH meter.

[0036] ② When determining total organic carbon (TOC), the potassium dichromate-sulfuric acid oxidation method combined with ferrous sulfate titration was used.

[0037] In this embodiment, 0.25g (accurate to 0.0001g) of sample is weighed and poured into a dry hard glass test tube. 10ml of 0.136mol / L potassium dichromate-sulfuric acid (K₂Cr₂O₇-H₂SO₄) solution is accurately added using a pipette. A small funnel is then placed at the mouth of the test tube, and the solution is left to stand for at least 4 hours until it turns black. The sample is then placed in a vegetable oil bath at 170℃-180℃. Timing begins when the liquid in the test tube boils and bubbles appear. The tube is boiled for 5 minutes. The test tube is then removed, allowed to cool slightly, and the exterior oil is wiped clean. After cooling, the contents of the test tube are carefully and thoroughly transferred into a 250ml Erlenmeyer flask, bringing the total volume to 60-70ml. The sulfuric acid concentration is maintained at 1-1.5mol / L, and the solution should be orange-yellow or pale yellow at this point. Then add 3-4 drops of o-phenanthroline indicator and titrate with 0.2 mol / L standard ferrous sulfate (FeSO4) solution. The endpoint is reached when the solution changes from yellow through green and light green to brownish-red. Perform three blank tests simultaneously with the sample determination and take the average value.

[0038] Results Calculation: In this reaction, the average oxidation rate of organic matter was 90%, so the oxidation correction constant was 100 / 90, which is 1.1. The calculation formula is as follows: Soil organic carbon g / kg = ((V0-V)N×0.003×1.1) / sample weight×0.001; In the formula: V0 is the volume of ferrous sulfate used in titrating the blank solution, in ml; V represents the volume of ferrous sulfate used in titrating the sample solution, in ml; N represents the concentration of standard ferrous sulfate, in mol / L.

[0039] ③ Both total nitrogen (TN) and total phosphorus (TP) were determined by chemical discontinuity analyzer after digestion with concentrated sulfuric acid and perchloric acid.

[0040] In this embodiment, 0.2500g of soil sample was weighed into a 100mL graduated digestion tube, 5mL of concentrated sulfuric acid was added, and after shaking well, 10 drops of perchloric acid were added and digested in a digestion furnace. After digestion, the sample was cooled and brought to a final volume of 500mL. After filtration or clarification, the sample was ready for analysis, and three blanks were digested at the same time. Finally, the sample was determined using a chemical discontinuity analyzer.

[0041] Experimental results are as follows Figures 3-6 As shown, from Figure 3 It can be seen that after leaching, the soil nutrients, namely total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP), did not change significantly (p>0.05). However, leaching significantly altered soil pH and aluminum concentration. Soil pH decreased from 5.01±0.05 in the original ore sample to 3.61, indicating increased soil acidification. Meanwhile, soil aluminum concentration increased from 1.97±0.59 g / kg in the original ore sample to 3.69±0.25 g / kg, indicating that the leaching process trapped a large amount of aluminum in the soil, resulting in a significant increase in soil aluminum content.

[0042] Low soil pH and low soil nutrient content are both unfavorable to vegetation growth. In order to explore soil remediation technology and screen plant resistance, a soil replacement experiment was conducted. By comparing the results after soil replacement, it was found that soil replacement significantly increased soil nutrient content and improved soil pH, which increased to 6.05±0.02.

[0043] like Figure 4 As shown, by comparing the survival status of vegetation, it was found that five vegetation species, namely foxtail grass, caragana, pigweed, sumac, and sea buckthorn, could grow well in the original ore soil, while only caragana survived in the leached soil, but its growth was severely inhibited and the aboveground biomass did not increase.

[0044] For imported soil, although this invention improves soil pH and soil nutrient content, only *Caragana korshinskii* grows well, such as... Figure 5 and Figure 6 As shown, comparing the plant height and biomass of Caragana korshinskii in the three soil groups, it was found that Caragana korshinskii had the best growth status in the imported soil, with plant height and aboveground biomass significantly higher than those in the original mineral soil.

[0045] In summary, after leaching, the soil pH and nutrient content in the mining area decreased significantly, seriously threatening plant growth. By comparing the growth status of plants, it was found that Caragana korshinskii can grow well and is an ideal vegetation for tailings remediation.

[0046] S6. Based on the data measured in S5, and according to plant survival status, biomass accumulation, and adaptability to the soil environment, acid-tolerant and barren-tolerant resistant plants were screened. The screening criteria for resistant plants were as follows: Plants that can survive in substrate 1 or substrate 2 and can increase soil pH, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP).

[0047] S7. Based on the principle of complementary ecological niches, this principle comprehensively considers the differences in ecological niches due to different germination characteristics and light requirements of plants, as well as the mutually promoting growth relationships between plant species, especially considering the rapid germination of herbaceous plants and their nurturing effect on the germination of woody plants. Accordingly, the screened resistant plants were combined into life-form combinations of herbs, shrubs, and vines. The seed mixing ratio was as follows: seeds of species of the same life-form were mixed in equal weight proportions; shrub, herbaceous, and vine seeds were mixed in a weight ratio of 2-3:6-9:1-5, thereby constructing an artificial seed bank.

[0048] After soil improvement, an artificial seed bank was constructed using seeds from 16 plant species, including nine herbaceous plants, six shrubs, and one vine, as shown in Table 1. The shrubs included sisal, indigofera multiflora, caragana, cassia biloba, castor bean, and sumac; the herbaceous plants included purslane, vetiver, miscanthus, foxtail grass, ryegrass, dandelion, coreopsis, cosmos, and zinnia; and the vine was kudzu. The plant seeds were thoroughly mixed and administered at a concentration of 15-30 g / m³. 2 Spread the seeds evenly, and finally spread a thin layer of soil on top.

[0049] Table 1 Plant types in artificial seed banks

[0050] S8. Sow the mixed seeds from the artificial seed bank evenly on the surface of the improved rare earth mine slope soil at an average rate of 20g per square meter, and cover with a thin layer of soil to complete vegetation restoration.

[0051] Before restoration, the land was bare and devoid of vegetation. After one month of restoration, vegetation coverage reached 70%-80%. Figure 7 Figures (a)-(f) show the partial and overall vegetation restoration before and after restoration, respectively. Field investigations revealed that the original ore deposit had a vegetation coverage of 80%-90%, with low species diversity and a simple structure. Therefore, it can be concluded that after one month of restoration, the vegetation coverage can reach 90% of the original ore deposit.

[0052] Therefore, the present invention adopts the above-mentioned method for screening and constructing a rare earth mine soil seed bank based on niche complementarity, which can effectively screen out resistant plants suitable for leaching soils of ion-adsorption rare earth mines. The constructed artificial seed bank can rapidly increase vegetation coverage, improve the soil ecological environment, and provide reliable technical support for the ecological restoration of ion-adsorption rare earth mines.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for screening and constructing a rare earth mine soil seed bank based on niche complementarity, characterized in that, Includes the following steps: S1. Prepare three types of soil substrates, namely substrate 1, substrate 2 and substrate 3; S2. Based on the survey results of the original community of unmined rare earth mines, herbaceous plants, shrubs and vine seedlings were selected as candidate plants. S3. Select healthy seeds from candidate plants that need to germinate, pre-treat them, and place them in an artificial climate culture chamber for germination culture to obtain germinating seedlings. S4. Plant the germinating seedlings or transplanted seedlings in three types of soil substrates respectively, control the planting density and maintenance conditions, and observe and record the plant growth status and plant height. S5. Determine the aboveground biomass and underground root biomass of the plants, and simultaneously determine the pH, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and aluminum concentration of the three types of soil matrices. S6. Based on the data measured in S5, resistant plants that are tolerant to acidification and poor soil were screened out. S7. Based on the principle of complementary ecological niches, the selected resistant plants are combined into herbaceous, shrub, and vine species to construct an artificial seed bank; S8. Evenly sow the mixed seeds from the artificial seed bank onto the surface of the improved rare earth mine soil, and cover with a thin layer of soil to complete vegetation restoration.

2. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 1, characterized in that, In S1, matrix 1 is rare earth tailings after ammonium sulfate leaching, matrix 2 is rare earth tailings with aluminum content adjusted after aluminum sulfate leaching, and matrix 3 is an improved matrix composed of rare earth tailings with aluminum content adjusted after aluminum sulfate leaching and soil remediation agent. The soil remediation agent is made of red and yellow soil, organic fertilizer and inorganic fertilizer in a ratio of 80~100:10~20:1~5, of which the organic fertilizer is chicken and duck manure, cake fertilizer or biochar.

3. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 2, characterized in that, In S2, candidate plants include foxtail grass, sumac, sea buckthorn, caragana, pigweed, and cassia bipoda to ensure complementary ecological niche differences.

4. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 3, characterized in that, In S3, the candidate plants to be germinated include foxtail grass, sumac, sea buckthorn, caragana, and pigweed. The pretreatment process is as follows: One hundred seeds of each plant were selected and soaked in a 0.5 g / L KMnO4 solution for 24 hours, and rinsed with water at least three times. Wash the petri dishes with sterile water and dry them at high temperature for later use. Line the petri dishes with a layer of moistened absorbent cotton. Prepare 5 petri dishes for each type of plant and sow 20 seeds evenly in each petri dish. They were cultured in an artificial climate incubator with conditions of 25°C, 60% humidity, and 20% light intensity, alternating between day and night every 12 hours. During the germination period, spray an appropriate amount of distilled water on each petri dish daily, observe and record the seed germination status, and obtain germinating seedlings.

5. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 4, characterized in that, S4 specifically refers to: Germinating seedlings or transplanted seedlings were planted in three types of soil substrates, using 7cm×7cm×7.5cm square flower pots, with 5 pots of each type of plant planted in each type of soil substrate; Among them, the planting density of foxtail grass, caragana, pig manure bean, sumac, sea buckthorn and double-pod cassia is 5 plants per pot; During the plant's growth and maintenance period, water it once every other day, and observe and record the plant's growth status and height.

6. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 5, characterized in that, In S5, the process of measuring the aboveground biomass and underground root biomass of plants is as follows: Surviving plants were harvested from the three types of soil substrates and placed into resealable bags; After rinsing, the above-ground parts and roots of each plant are separated and placed in a drying oven to dry for 24 hours; The dry weight of the aboveground parts and roots of each plant under three types of soil substrates was determined using an analytical balance to characterize the aboveground biomass and underground root biomass.

7. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 6, characterized in that, In S5, soil samples were collected from each of the three types of soil substrates used for planting each plant. The samples were spread out on clean paper in a thin layer and allowed to air dry naturally. A suitable amount of the dried soil sample was taken using the quartering method. Stones and plant debris were removed. The sample was then crushed, passed through a 60-mesh sieve, and placed in a clean resealable bag for later use. When measuring soil pH, mix soil with boiled and cooled distilled water at a mass-to-volume ratio of 2:5, shake for 2 minutes, centrifuge at maximum speed for 10 minutes, measure and record the pH value of the supernatant using a pH meter. Total organic carbon (TOC) was determined using a combination of potassium dichromate-sulfuric acid oxidation and ferrous sulfate titration. Both total nitrogen (TN) and total phosphorus (TP) were determined by chemical discontinuity analyzer after digestion with concentrated sulfuric acid and perchloric acid.

8. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 7, characterized in that, In S6, based on the data measured in S5, acid-tolerant and barren-tolerant resistant plants were screened according to plant survival status, biomass accumulation, and adaptability to the soil environment. The screening criteria for resistant plants were as follows: Plants that can survive in substrate 1 or substrate 2 and can increase soil pH, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP).

9. The method for screening and constructing a rare earth mine soil seed bank based on niche complementarity according to claim 8, characterized in that, In S7, the constructed artificial seed bank includes shrubs, herbs, and vines; Shrubs include sisal, indigofera, sage, castor bean, and sumac; herbs include dung bean, vetiver, miscanthus, foxtail grass, ryegrass, dandelion, coreopsis, cosmos, and zinnia; vines include kudzu.

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