A method for ecological restoration of mine slopes

Abstract

The present invention relates to a method for ecological restoration of mine slopes, mainly by using a slope hanging net soil spraying technology, combined with the installation of anti-skid slow-release ecological bags, which can not only increase friction to prevent the slope soil from sliding, but also provide long-term nutrients and water for plant growth; at the same time, the method of combining the soil bottom spraying matrix and the surface spraying matrix developed by the present invention, combined with the soil repair plant seed mixed planting spraying technology, alleviates the heavy metal pollution in the mine soil. The method of the present invention can both green the exposed mine slopes, promote vegetation recovery and growth, and repair the heavy metal contaminated soil in the mine.

Description

Technical Field

[0001] The invention relates to a method for ecological restoration of a mine slope, and belongs to the field of soil restoration. Background Art

[0002] my country is rich in mineral resources, and mineral development is closely tied to both resources and the environment. While the booming mining industry has made significant contributions to local economic development, mining activities also cause ecological damage and pollution. As vast swaths of mining resources are mined, vast quantities of mining waste, including stripping soil and abandoned pits, are left behind, exposing vast areas of rock. These exposed "scars" cause soil erosion, pose safety risks, and damage the ecological environment. In some areas, mining has even led to environmental pollution, ground subsidence, rock slides, mudslides, and other geological and environmental problems.

[0003] The most important aspect of remediating abandoned mines is to "green" the mountains. It also requires integrating ecological construction, land reclamation, resource development, and landscape construction to maximize overall benefits. However, the aforementioned ecological greening approach to mine restoration only superficially improves the mine environment, while remaining largely unaddressed by the heavy metal pollution problem in the mining area, the biggest challenge in mine restoration. Therefore, a method for ecological restoration of mine slopes is urgently needed that can both green the mine slopes and restore vegetation growth while also repairing the heavy metal-contaminated soil in the mines. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for ecological restoration of mine slopes, comprising the following steps:

[0005] (1) Leveling and repairing the area

[0006] Use machinery and manual labor to trim the ground in the repair area, remove debris, backfill depressions, level the ground and compact it to ensure there is no looseness;

[0007] If there is a native topsoil layer in the restoration area, the topsoil should be collected and sieved for impurities and used as planting soil for later vegetation restoration and reconstruction; if there are native trees and shrubs in the restoration area, the vegetation should be transplanted and used for planting in the later vegetation restoration and reconstruction;

[0008] (2) Slope construction in the repair area

[0009] Drill holes and install steel bars every 0.5-1m along the slope surface. The hole depth is 40-50cm and the steel bar diameter is 12-14mm. The steel bars are exposed 5-10cm above the slope surface for surface mesh hanging.

[0010] (3) Installation of anti-slip slow-release eco-bags

[0011] On the steel bars of the slope, anti-skid slow-release eco-bags are fixedly installed. The anti-skid slow-release eco-bags are cylindrical bag-shaped objects with a diameter of 7-10 cm and a length of 1-2 m. They are made of biodegradable materials. The bags are pre-filled with slow-release water-retaining fertilizers. The slow-release water-retaining fertilizers are: 3mm humic acid granular fertilizers, 8mm humic acid granular fertilizers, 5mm polyacrylamide granules, 10mm polyacrylamide granules, slow-release urea, and sodium carboxymethyl cellulose powder, mixed in a volume ratio of 5:3:2:1:2:1.

[0012] The bag material slowly releases nutrients and can also store rainwater and provide moisture for plant growth. Each bag has a linking device at both ends, so that multiple bags can be connected and fixed horizontally on the slope. During installation, a horizontal groove is first opened on the slope, the size of which can accommodate the anti-skid slow-release eco-bag. The bag is then stuck in the horizontal groove on the slope and supported and fixed with steel bars. At the same time, the connection between each bag is also fixed to the slope with a fixing device. The horizontally installed anti-skid slow-release eco-bag can not only increase friction to prevent the soil on the slope from sliding, but also provide long-term nutrients and moisture for plant growth.

[0013] (4) Hanging mesh construction

[0014] Lay galvanized wire mesh according to the slope surface and fix it with wire ties to the slope steel bars. When hanging the mesh, the mesh surface should be as close to the slope surface as possible. The mesh size of the galvanized wire mesh is 5cm×5cm and the diameter is 2mm.

[0015] (5) Imported soil spraying matrix

[0016] The imported soil spraying matrix includes the bottom matrix and the surface matrix.

[0017] The bottom matrix is ​​an ecological concrete structure matrix, including: planting soil, cement, 5-8 cm corn stalk segments, rice husks, decomposed livestock manure, 3 mm polystyrene foam particles, and 10 mm polyacrylamide, the above raw materials are mixed in a volume ratio of 8:0.5:2:1:1.5:0.5:0.5;

[0018] The surface matrix is ​​an ecological restoration layer matrix, including: planting soil, 2-3 cm corn stalk segments, rice husks, decomposed livestock manure, 3 mm polystyrene foam particles, and 5 mm polyacrylamide; the above raw materials are mixed in a volume ratio of 8:3:1:2:1:1;

[0019] The planting soil includes the original topsoil layer of the restoration area in step (1), and / or soil sources selected nearby the restoration area. When taking soil from the soil sources selected nearby the restoration area, the surface humus layer should be dug and piled nearby for proper preservation. After the soil is taken, the surface humus layer should be re-laid and vegetation should be added to prevent soil erosion;

[0020] (6) Spray seeding construction

[0021] For bottom matrix spraying, mix the selected ecological concrete structure matrix materials evenly, and spray them evenly on the slope surface with a mud machine to a thickness of 10-15cm;

[0022] Spraying the surface matrix, mix the raw materials of the ecological restoration layer matrix evenly, and use a mud machine to spray evenly on the bottom matrix, with a thickness of 8-12cm;

[0023] Seed spraying: Specifically, mix soil remediation plant seeds, organic fertilizer powder, polyacrylamide 5mm, and paper pulp in a weight ratio of 0.5:2:2:5 and put them into the sprayer. Add water and stir evenly. Spray the mixture onto the surface substrate through a pressurized pipe. The spraying dosage of soil remediation plant seeds is 7-8g / m 2 The soil remediation plant seeds are a mixture of Dianthus fasciata, P. putuo, and Scutellaria baicalensis in a weight ratio of 3:2:1.

[0024] After the spraying is completed, cover the surface with a layer of non-woven fabric and fix the non-woven fabric on the slope with bamboo sticks; water it thoroughly when it is dry;

[0025] (7) Greening Planting

[0026] After the spraying of soil remediation plant seeds is completed, artificial sowing of tree and shrub seedlings is carried out. Trees, shrubs and greening are arranged according to a certain planting area ratio to achieve the best horizontal coverage, and the vertical structure of the community is reasonable and the ornamental value is strong;

[0027] For the first sowing, the seedlings of Cinnamomum camphora, Rhus chinensis, Liquidambar formosana, Sapium sebiferum, Casuarina equisetifolia, and Paulownia are mixed, with a sowing density of 6-10 seeds / m 2 ;

[0028] The second sowing: oleander, Amorpha fruticosa, Lespedeza, Cassia corymbosa, Indigofera chinensis, and seedlings are mixed in equal numbers; the sowing density is 15-20 seeds / m 2 ;

[0029] (8) Maintenance and management

[0030] After spraying, the maintenance period begins. Water is sprayed every day from 8 to 10 am and from 4 to 6 pm to ensure that the slope surface remains moist and does not produce surface runoff. A water-soluble compound fertilizer with an N:P:K ratio of 10:20:10 is applied every week at 2-5g / m 2 , until the seeds germinate and form a complete cover; one month after sowing, spray a mixed solution of potassium dihydrogen phosphate with a mass concentration of 0.5-1.0% and melatonin with a concentration of 80-100 μM / L. The mixed solution is prepared by first preparing each solution of the above concentration separately and then mixing them in equal volume proportions. Spray it together with water between 4 and 6 pm and spray it continuously for 3 days.

[0031] Beneficial effects of this application:

[0032] 1. The main heavy metals found in the soil of abandoned mining areas include copper, zinc, and lead. High levels of heavy metals and salinity place higher demands on the resilience of plants in mining areas. This application primarily explores plant combinations that are salt-tolerant, drought-resistant, and have strong heavy metal absorption capabilities, which are more conducive to the restoration of mining slopes.

[0033] 2. The slow-release ecological bag and guest soil spraying matrix of the present invention cooperate with plant combination to repair heavy metal pollution in abandoned mines. The soil heavy metal treatment effect of Example 1 of the present invention is the best, and the average reduction percentage of heavy metal content of lead, cadmium, mercury and arsenic can reach 32.98%, 35.15%, 29.73% and 38.67% respectively, indicating that the slow-release ecological bag and guest soil spraying double-layer matrix of the present invention can cooperate with plant combination to repair heavy metal pollution. In addition, the ratio of seed spraying of Dianthus strychnifolius, Putuo Dog Flower and Orchid Vanilla of the present invention affects the heavy metal remediation of the entire sample plot, among which the remediation efficiency is optimal when the mixing ratio is 3:2:1. By comparing the management methods after spraying, we also found that by applying high-phosphorus compound fertilizer and spraying potassium dihydrogen phosphate + melatonin in the later stage, plants can quickly resume growth on the contaminated sample plot and achieve better remediation effect.

[0034] 3. The slow-release eco-bags of the present invention can provide long-term nutrients for vegetation restoration on mine slopes. Experiments have shown that slow-release fertilizers and water-retaining agents of different particle sizes have a certain adsorption effect on heavy metal-contaminated soil. This experiment uses the adsorption of zinc and slow-release nitrogen as examples to determine the formula for the slow-release water-retaining fertilizer in the embodiments of the present invention. The slow-release water-retaining fertilizer is: 3mm humic acid granular fertilizer, 8mm humic acid granular fertilizer, 5mm polyacrylamide granules, 10mm polyacrylamide granules, slow-release urea, and sodium carboxymethyl cellulose powder, mixed in a volume ratio of 5:3:2:1:2:1. This has the highest adsorption capacity for heavy metal zinc. The water-retaining agent and slow-release fertilizer, as well as their particle size combination, have a synergistic effect. The particle size of the humic acid granular fertilizer should also be within a reasonable range to achieve the slow release of effective nitrogen. Excessively large particles affect the initial nitrogen release.

[0035] 4. The different guest soil formulations in this application significantly impacted the substrate's ventilation rate and lead removal rate. The base layer + surface layer formulation achieved the highest lead removal rate. By properly proportioning the two materials and adjusting the particle size, a suitable substrate ventilation rate for plant cultivation was achieved. Comparing the results with a single layer of guest soil, a two-layer substrate demonstrated optimal lead removal and ventilation. Furthermore, the thickness of the guest soil also impacted these two indicators: decreasing the guest soil thickness resulted in a corresponding decrease in heavy metal removal and ventilation, hindering vegetation recovery.

[0036] 5. Spraying corn stalks and husks into the guest soil not only increases friction and reduces soil erosion, but also improves substrate aeration. Without any of these substances, the guest soil formula's heavy metal adsorption and aeration rate are significantly reduced. The volume ratio and particle size ratio of polystyrene foam and polyacrylamide affect the guest soil formula's lead metal removal rate and substrate aeration rate. The combination of these two soil conditioners creates a lightweight, cohesive, and granular structure in the guest soil matrix, making it less susceptible to soil erosion, more agglomerable, and providing excellent aeration, providing a favorable growth environment for plants growing on the guest soil matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Abandoned mining area slope hanging net diagram of the present invention

[0038] Figure 2 Installation diagram of the anti-slip slow-release ecological bag of the present invention

[0039] Figure 3 The initial stage of vegetation restoration in abandoned mines according to the present invention

[0040] Figure 4 Half-year vegetation restoration diagram of abandoned mines in the present invention

[0041] Figure 5 One-year vegetation restoration diagram of abandoned mines in this invention DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The materials used in the present invention are all materials that can be purchased on the market, including humic acid granular fertilizer 3mm, humic acid granular fertilizer 8mm, polyacrylamide granule size 5mm, polyacrylamide granule size 10mm, polystyrene foam granule 3mm, slow-release urea, and sodium carboxymethyl cellulose powder; the cement is ordinary Portland cement.

[0043] Example 1:

[0044] A method for ecological restoration of a mine slope comprises the following steps:

[0045] (1) Leveling and repairing the area

[0046] Use machinery and manual labor to trim the ground in the repair area, remove debris, backfill depressions, level the ground and compact it to ensure there is no looseness;

[0047] If there is a native topsoil layer in the restoration area, the topsoil should be collected and sieved for impurities and used as planting soil for later vegetation restoration and reconstruction; if there are native trees and shrubs in the restoration area, the vegetation should be transplanted and used for planting in the later vegetation restoration and reconstruction;

[0048] (2) Slope construction in the repair area

[0049] Punch holes every 1m along the slope surface to install a steel bar. The hole depth is 50cm and the steel bar diameter is 12mm. The steel bar is exposed 10cm above the slope surface for surface mesh hanging.

[0050] (3) Installation of anti-slip slow-release eco-bags

[0051] On the steel bars of the slope, an anti-skid slow-release eco-bag is fixedly installed. The anti-skid slow-release eco-bag is a cylindrical bag-shaped object with a diameter of 8 cm and a length of 1.5 m. It is made of biodegradable material and is pre-filled with a slow-release water-retaining fertilizer. The slow-release water-retaining fertilizer is: 3mm humic acid granular fertilizer, 8mm humic acid granular fertilizer, 5mm polyacrylamide granular particle size, 10mm polyacrylamide granular particle size, slow-release urea, and sodium carboxymethyl cellulose powder, mixed in a volume ratio of 5:3:2:1:2:1;

[0052] The bag material slowly releases nutrients and can also store rainwater and provide moisture for plant growth. Each bag has a linking device at both ends, so that multiple bags can be connected and fixed horizontally on the slope. During installation, a horizontal groove is first opened on the slope, the size of which can accommodate the anti-skid slow-release eco-bag. The bag is then stuck in the horizontal groove on the slope and supported and fixed with steel bars. At the same time, the connection between each bag is also fixed to the slope with a fixing device. The horizontally installed anti-skid slow-release eco-bag can not only increase friction to prevent the soil on the slope from sliding, but also provide long-term nutrients and moisture for plant growth.

[0053] (4) Hanging mesh construction

[0054] Lay galvanized wire mesh according to the slope surface and fix it with wire ties to the slope steel bars. When hanging the mesh, the mesh surface should be as close to the slope surface as possible. The mesh size of the galvanized wire mesh is 5cm×5cm and the diameter is 2mm.

[0055] (5) Imported soil spraying matrix

[0056] The imported soil spraying matrix includes the bottom matrix and the surface matrix.

[0057] The bottom matrix is ​​an ecological concrete structure matrix, including: planting soil, cement, 8cm corn stalks, rice husks, decomposed livestock manure, 3mm polystyrene foam particles, and 10mm polyacrylamide, and the above raw materials are mixed in a volume ratio of 8:0.5:2:1:1.5:0.5:0.5;

[0058] The surface matrix is ​​an ecological restoration layer matrix, comprising: planting soil, 3cm corn stalk segments, rice husks, decomposed livestock manure, 3mm polystyrene foam particles, and 5mm polyacrylamide; the above raw materials are mixed in a volume ratio of 8:3:1:2:1:1;

[0059] The planting soil includes the original topsoil layer of the restoration area in step (1), and / or soil sources selected nearby the restoration area. When taking soil from the soil sources selected nearby the restoration area, the surface humus layer should be dug and piled nearby for proper preservation. After the soil is taken, the surface humus layer should be re-laid and vegetation should be added to prevent soil erosion;

[0060] (6) Spray seeding construction

[0061] For bottom matrix spraying, mix the selected ecological concrete structure matrix materials evenly, and spray them evenly on the slope surface with a mud machine to a thickness of 10cm;

[0062] Spraying the surface matrix: Mix and stir the raw materials of the ecological restoration layer matrix evenly, and spray it evenly on the bottom matrix with a mud machine to a thickness of 8 cm;

[0063] Seed spraying: Specifically, mix soil remediation plant seeds, organic fertilizer powder, polyacrylamide 5mm, and paper pulp in a weight ratio of 0.5:2:2:5 and put them into the sprayer. Add water and stir evenly. Spray the mixture onto the surface substrate through a pressurized pipe. The spraying dosage of soil remediation plant seeds is 7-8g / m 2 The soil remediation plant seeds are a mixture of Dianthus superbus, Psoralea corylifolia and Scutellaria baicalensis in a weight ratio of 3:2:1.

[0064] After the spraying is completed, cover the surface with a layer of non-woven fabric and fix the non-woven fabric on the slope with bamboo sticks; water it thoroughly when it is dry;

[0065] (7) Maintenance and management

[0066] After spraying, the maintenance period begins. Water is sprayed every day from 8 to 10 am and from 4 to 6 pm to ensure that the slope surface remains moist and does not produce surface runoff. 5g / m3 of water-soluble compound fertilizer with N:P:K ratio of 10:20:10 is applied every week. 2 , until the seeds germinate and form a complete cover; one month after sowing, spray a mixed solution of potassium dihydrogen phosphate with a mass concentration of 1.0% and melatonin with a concentration of 100 μM / L. The mixed solution is prepared by first preparing each solution of the above concentration separately and then mixing them in equal volume proportions. Spray it together with water between 4 and 6 pm and spray it continuously for 3 days.

[0067] Example 2

[0068] A method for ecological restoration of a mine slope comprises the following steps:

[0069] (1) Leveling and repairing the area

[0070] Use machinery and manual labor to trim the ground in the repair area, remove debris, backfill depressions, level the ground and compact it to ensure there is no looseness;

[0071] If there is a native topsoil layer in the restoration area, the topsoil should be collected and sieved for impurities and used as planting soil for later vegetation restoration and reconstruction; if there are native trees and shrubs in the restoration area, the vegetation should be transplanted and used for planting in the later vegetation restoration and reconstruction;

[0072] (2) Slope construction in the repair area

[0073] Drill holes every 1m along the slope surface to install a steel bar. The hole depth is 50cm and the steel bar diameter is 12mm. The steel bar is exposed 10cm above the slope surface for surface mesh hanging.

[0074] (3) Installation of anti-slip slow-release eco-bags

[0075] On the steel bars of the slope, an anti-skid slow-release eco-bag is fixedly installed. The anti-skid slow-release eco-bag is a cylindrical bag-shaped object with a diameter of 8 cm and a length of 1.5 m. It is made of biodegradable material and is pre-filled with a slow-release water-retaining fertilizer. The slow-release water-retaining fertilizer is: 3mm humic acid granular fertilizer, 8mm humic acid granular fertilizer, 5mm polyacrylamide granular particle size, 10mm polyacrylamide granular particle size, slow-release urea, and sodium carboxymethyl cellulose powder, mixed in a volume ratio of 5:3:2:1:2:1;

[0076] The bag material slowly releases nutrients and can also store rainwater and provide moisture for plant growth. Each bag has a linking device at both ends, so that multiple bags can be connected and fixed horizontally on the slope. During installation, a horizontal groove is first opened on the slope, the size of which can accommodate the anti-skid slow-release eco-bag. The bag is then stuck in the horizontal groove on the slope and supported and fixed with steel bars. At the same time, the connection between each bag is also fixed to the slope with a fixing device. The horizontally installed anti-skid slow-release eco-bag can not only increase friction to prevent the soil on the slope from sliding, but also provide long-term nutrients and moisture for plant growth.

[0077] (4) Hanging mesh construction

[0078] Lay galvanized wire mesh according to the slope surface and fix it with wire ties to the slope steel bars. When hanging the mesh, the mesh surface should be as close to the slope surface as possible. The mesh size of the galvanized wire mesh is 5cm×5cm and the diameter is 2mm.

[0079] (5) Foreign soil spraying matrix

[0080] The imported soil spraying matrix includes the bottom matrix and the surface matrix.

[0081] The bottom matrix is ​​an ecological concrete structure matrix, including: planting soil, cement, 8cm corn stalks, rice husks, decomposed livestock manure, 3mm polystyrene foam particles, and 10mm polyacrylamide, and the above raw materials are mixed in a volume ratio of 8:0.5:2:1:1.5:0.5:0.5;

[0082] The surface matrix is ​​an ecological restoration layer matrix, comprising: planting soil, 3cm corn stalk segments, rice husks, decomposed livestock manure, 3mm polystyrene foam particles, and 5mm polyacrylamide; the above raw materials are mixed in a volume ratio of 8:3:1:2:1:1;

[0083] The planting soil includes the original topsoil layer of the restoration area in step (1), and / or soil sources selected nearby the restoration area. When taking soil from the soil sources selected nearby the restoration area, the surface humus layer should be dug and piled nearby for proper preservation. After the soil is taken, the surface humus layer should be re-laid and vegetation should be added to prevent soil erosion;

[0084] (6) Spray seeding construction

[0085] For bottom matrix spraying, mix the selected ecological concrete structure matrix materials evenly, and spray them evenly on the slope surface with a mud machine to a thickness of 10cm;

[0086] Spraying the surface matrix: Mix and stir the raw materials of the ecological restoration layer matrix evenly, and spray it evenly on the bottom matrix with a mud machine to a thickness of 8 cm;

[0087] Seed spraying: Specifically, mix soil remediation plant seeds, organic fertilizer powder, polyacrylamide 5mm, and paper pulp in a weight ratio of 0.5:2:2:5 and put them into the sprayer. Add water and stir evenly. Spray the mixture onto the surface substrate through a pressurized pipe. The spraying dosage of soil remediation plant seeds is 7-8g / m 2 The soil remediation plant seeds are a mixture of Dianthus superbus, Psoralea corylifolia and Scutellaria baicalensis in a weight ratio of 3:2:1.

[0088] After the spraying is completed, cover the surface with a layer of non-woven fabric and fix the non-woven fabric on the slope with bamboo sticks; water it thoroughly when it is dry;

[0089] (7) Greening Planting

[0090] After the spraying of soil remediation plant seeds, artificial sowing of tree and shrub seedlings is carried out. Trees, shrubs and greening are arranged according to a certain planting area ratio to achieve the best horizontal coverage, and the vertical structure of the community is reasonable and the ornamental effect is strong.

[0091] For the first sowing, the seedlings of Cinnamomum camphora, Rhus chinensis, Liquidambar formosana, Sapium sebiferum, Casuarina equisetifolia, and Paulownia were mixed, with a sowing density of 6 seeds / m 2 ;

[0092] The second sowing was done with a mixture of oleander, Amorpha fruticosa, Lespedeza, Cassia corymbosa, and Indigofera chinensis seedlings in equal numbers; the sowing density was 15 seeds / m 2 .

[0093] (8) Maintenance and management

[0094] After spraying, the maintenance period begins. Water is sprayed every day from 8 to 10 am and from 4 to 6 pm to ensure that the slope surface remains moist and does not produce surface runoff. 5g / m3 of water-soluble compound fertilizer with N:P:K ratio of 10:20:10 is applied every week. 2 , until the seeds germinate and form a complete cover; one month after sowing, spray a mixed solution of potassium dihydrogen phosphate with a mass concentration of 1.0% and melatonin with a concentration of 100 μM / L. The mixed solution is prepared by first preparing each solution of the above concentration separately and then mixing them in equal volume proportions. Spray it together with water between 4 and 6 pm and spray it continuously for 3 days.

[0095] Experiment 1: Experiment on the restoration of heavy metals in abandoned mines by combining slow-release ecological bags and imported soil spraying matrix with plants

[0096] Experimental method: Taizhou abandoned mines were used as research plots, and the restoration method was the same as that in Example 1. The changes in heavy metal enrichment in plants after the vegetation restoration of abandoned mines were studied. The experimental plot was 1m*1m, and the observation period for mine restoration and planting was 1 year. Samples were taken from the same position before restoration and 1 year after restoration, with three plots for each treatment, and collected according to the 5-point sampling method. Before vegetation restoration, soil was collected from the plot at a depth of 5cm-20cm, mixed into 1 sample, and repeated 3 times. The weight of each sample was not less than 1kg. Since the original ground was not covered with soil, there were tens of centimeters of foreign soil after ecological restoration. Therefore, soil was collected from the same position at a depth of 20cm-30cm after 1 year of restoration, mixed into 1 sample, and repeated 3 times. The weight of each sample was not less than 1kg. After the soil samples were naturally air-dried in the laboratory, they were crushed and ground with an agate mortar, passed through a 100-mesh nylon sieve, and stored for future use. Detection method: Lead and cadmium were determined in accordance with the "Soil quality - Determination of lead and cadmium - Graphite furnace atomic absorption spectrophotometry" (GB / T 17141-1997), and total mercury and total arsenic were determined in accordance with the "Soil quality - Determination of total mercury and total arsenic - Atomic fluorescence method - Part 1-2 Determination of total mercury and total arsenic in soil" (GB / T 22105.2-2008).

[0097] Experimental Example 1

[0098] The mine ecological restoration method is the same as that in Example 1, except that step (3) of installing the anti-slip slow-release ecological bag is omitted.

[0099] Experimental Example 2

[0100] The mine ecological restoration method is the same as that in Example 1, except that the bottom substrate spraying in step (5) is omitted and only one layer is sprayed.

[0101] Experimental Example 3

[0102] The mine ecological restoration method is the same as that in Example 1, except that the surface matrix spraying in step (5) is omitted and only one layer is sprayed.

[0103] Experimental Example 4

[0104] The mine ecological restoration method is the same as that in Example 1, wherein seeds of Dianthus superbus, P. putuoensis, and Scutellaria baicalensis are sprayed in a weight ratio of 1:1:1.

[0105] Experimental Example 5

[0106] The mine ecological restoration method is the same as that in Example 1, wherein seeds of Dianthus superbus, P. putuoensis, and Scutellaria baicalensis are sprayed in a weight ratio of 1:2:3.

[0107] Experimental Example 6

[0108] The mine ecological restoration method is the same as that in Example 1, wherein only the Dianthus superbus seeds are sprayed.

[0109] Experimental Example 7

[0110] The mine ecological restoration method is the same as that in Example 1, wherein only the Putuo Gouwawa flower seeds are sprayed.

[0111] Experimental Example 8

[0112] The mine ecological restoration method is the same as that in Example 1, wherein only vanilla seeds are sprayed.

[0113] Comparative Example 1

[0114] The mine ecological restoration method is the same as that in Example 1, wherein seeds of Dianthus superbus, Psoralea corylifolia, and Cynodon dactylon are sprayed in a weight ratio of 3:2:1.

[0115] Comparative Example 2

[0116] The mine ecological restoration method is the same as that in Example 1, wherein seeds of thatch, Putuo dogwawa flower, and bermudagrass are sprayed in a weight ratio of 3:2:1.

[0117] Comparative Example 3

[0118] The mine ecological restoration method is the same as that in Example 1, wherein a potassium dihydrogen phosphate solution with a mass concentration of 1.0% is sprayed one month after sowing.

[0119] Comparative Example 4

[0120] The mine ecological restoration method is the same as that in Example 1, wherein a melatonin solution with a concentration of 100 μM / L is sprayed one month after sowing.

[0121] Comparative Example 5

[0122] The mine ecological restoration method is the same as that in Example 1, wherein a water-soluble compound fertilizer with an N:P:K ratio of 10:10:10 is applied every week.

[0123] Test results:

[0124] Table 1 Results of the combination of slow-release eco-bags and imported soil spraying matrix in conjunction with plants to repair heavy metal pollution

[0125]

[0126] The slow-release ecological bag of the present invention and the collaborative plant combination of the guest soil spraying matrix can repair the heavy metal pollution of abandoned mines. By sampling and measuring the sample site before restoration, it can be seen that the 4 common soil heavy metal contents in the area all exceed the second type of construction land soil pollution screening value in the "Soil Environmental Quality Construction Land Soil Pollution Risk Management Standard (Trial)" GB36600-2018, wherein lead exceeds 1.3 times, cadmium exceeds 2.5 times, mercury exceeds 1.9 times, and arsenic exceeds 3.1 times. Taking the above-mentioned multiple test schemes, after 1 year of plant growth, the heavy metal content in the soil can be reduced, wherein the soil heavy metal treatment effect of Example 1 is the best, and the average reduction percentage of the heavy metal content of lead, cadmium, mercury and arsenic can reach 32.98%, 35.15%, 29.73% and 38.67%. The heavy metal lead content in the contaminated soil after repair can meet the requirements of the second type of construction land soil pollution screening value, and other soil heavy metal contents are expected to meet the repair requirements in the second year. At the same time, the plants in the sample plots should be regularly cut and treated harmlessly to accelerate the adsorption of heavy metals in the soil by the plants.

[0127] It can be seen from Experimental Examples 1-3 that the slow-release ecological bag and the double-layer matrix of the guest soil spraying of the present invention can cooperate with the plant combination to repair heavy metal pollution. If the laying of the slow-release ecological bag of the present invention is omitted, or only one layer of guest soil matrix is ​​laid, the repair effect on the soil will decrease. It can be seen from Experimental Examples 4-8 that the ratio of the seeds of the present invention, the seed spraying of the dianthus, the hyacinthus putuo and the angelica affects the heavy metal repair of the entire sample site. Among them, the repair efficiency is optimal when the mixing ratio is 3:2:1, and it is better than the repair effect of using one of the plants alone, especially the highest repair rate for arsenic. After the other plant combinations of Control Examples 1-2, the effect is not as good as the plant combination of the present application. Through comparative studies on the management methods after spraying in Control Examples 3-5, we found that by applying high-phosphorus compound fertilizers and spraying potassium dihydrogen phosphate + melatonin in the later stage, plants can quickly resume growth on the contaminated sample site and achieve better repair effects. Our research group has found through years of research that the application of melatonin can increase the salt tolerance and drought resistance of plants. Combined with the application of high-phosphorus fertilizers, it can improve the stress resistance of plants and promote their repair of heavy metal-contaminated soils.

[0128] Experiment 2: Adsorption and slow-release test of slow-release water-retaining fertilizer composed of water-retaining agents with different particle sizes

[0129] Experimental Method: A polymer resin mesh material with ultra-high water absorption and retention capacity, combined with slow-release fertilizer, forms an anti-skid, slow-release eco-bag installed on a slope, which slowly releases nutrients from the fertilizer. This experiment studies the slow-release, water-retaining fertilizer formula in the slow-release eco-bag, specifically a combination of water-retaining agents of varying particle sizes (see the table below for different volume ratios), and their effects on the adsorption of heavy metals in the soil and the slow-release of nitrogen when combined with slow-release fertilizer. The experimental materials used included water-retaining agents (polyacrylamide particles) of varying particle sizes produced by Beijing Hanlimiao New Technology Co., Ltd., humic acid granular fertilizers of varying particle sizes produced by Shanxi Jiayou Humic Acid Technology Co., Ltd., and slow-release urea produced by Hebei Devoduo Fertilizer Co., Ltd. The adsorption test is an artificial simulation test, specifically (1) isothermal adsorption experiment: accurately weigh 0.5g of slow-release water-retaining fertilizers with different ratios, place them in different 250mL beakers, add 5mg / L zinc sulfate solution, the initial pH of the solution is 6.8, let it stand for 24h at room temperature and pressure, filter, weigh the gel mass formed by the slow-release water-retaining fertilizer, and measure the volume of the filtrate and the zinc ion concentration; the zinc ion concentration in the filtrate is measured using a multi-parameter water quality analyzer GDYS-201MPAN, and repeat 3 times; (2) slow-release experiment of nitrogen by slow-release water-retaining fertilizer Test: Accurately weigh 0.5g of slow-release water-retaining fertilizer with different proportions, place them in different 250mL beakers, and let them stand for 24h. The initial pH of the solution is 6.8. After the slow-release water-retaining fertilizer is saturated with adsorption, filter it, weigh the mass of the gel, collect the filtrate, and then put the gel in an oven to dry to constant weight. Put it in distilled water and let it stand for 24h / 72h, then filter it, weigh the mass of the gel, determine the volume of the filtrate and the total nitrogen content, and then put it in an oven to dry to constant weight. Calculate the nitrogen release of the slow-release water-retaining fertilizer, and repeat 3 times; the total nitrogen content is determined by the sulfuric acid-hydrogen peroxide digestion Nessler colorimetric method. Zinc absorption (mg·g -1 ) Calculation method: Q = (C0V0-C1V1) / m, where: C0—original solution concentration, mg·L -1 ; V0—volume of added solution, L; C1—concentration of filtrate after filtration of added solution, mg·L -1 ; V1—volume of filtrate after adding solution and filtering, L; m—mass of slow-release water-retaining fertilizer before adding solution. Nitrogen release (mg·g -1 ) Calculation method: Q s =C2·V2 / m, where: C2—total nitrogen content in the filtrate after filtration with distilled water, mg·L -1 ; V2—the volume of the filtrate after adding distilled water and filtering, L; m—the mass of the slow-release water-retaining fertilizer before adding the solution.

[0130] Table 2 Adsorption and slow-release test of slow-release water-retaining fertilizer composed of water-retaining agents with different particle sizes

[0131]

[0132]

[0133] Test results: The slow-release ecological bag of the present invention can provide nutrients for vegetation restoration on mine slopes for a long time. Through experiments, it is found that slow-release fertilizers and water-retaining agents of different particle sizes have a certain adsorption effect on heavy metal contaminated soil. In this experiment, the adsorption amount of zinc and slow-release nitrogen are taken as examples to obtain the formula of the slow-release water-retaining fertilizer in the embodiment of the present invention, that is, the slow-release water-retaining fertilizer is: humic acid granular fertilizer 3mm, humic acid granular fertilizer 8mm, polyacrylamide particle size 5mm, polyacrylamide particle size 10mm, slow-release urea, sodium carboxymethyl cellulose powder, mixed in a volume ratio of 5:3:2:1:2:1, and the adsorption amount of heavy metal zinc is the highest. The water-retaining agent and slow-release fertilizer, as well as the combination of their particle sizes, have a synergistic effect. Compared with a single test of a water-retaining agent or slow-release fertilizer with a particle size, the formula of the present application has the best effect in adsorbing heavy metals. At the same time, comparing the nitrogen release in 24 hours and 72 hours, the nitrogen release of this application is more balanced. Among them, if the particles of the water retaining agent are too large, the nitrogen release will be significantly reduced, and if the particles are too small, the nitrogen release rate will be too fast, which is not conducive to long-term plant nutrient supply. At the same time, the particle size of humic acid granular fertilizer should also be within a reasonable range to achieve a slow release of effective nitrogen. Excessive particles affect the release of nitrogen in the early stage.

[0134] Experiment 3: Effect of imported soil formula on mine soil remediation

[0135] Test method: The ability of the modified matrix formed by different guest soil formulas to repair heavy metal contaminated soil was studied, with heavy metal lead removal rate and matrix ventilation volume as indicators. Among them, the lead removal rate was specifically prepared to simulate the preparation of lead-contaminated soil. It was calculated with a moisture content of 30%. A certain concentration of Pb(NO3)2 solution was added to the matrix soil to control the Pb content in the soil to 200 mg / L. After mixing evenly, it was placed in a constant temperature incubator for 90 days. It was taken out every 10 days and deionized water was added to the contaminated soil. The relative moisture content of the soil was controlled to be about 30% by the mass method. The materials at the above test levels were added to simulate the repair for 30 days and the Pb content was determined. 2+ Concentration. Removal rate of heavy metal lead = (C0-C1) / C0, where C0 is the lead concentration of the initial solution before the test (mg / L); C1 is the lead concentration of the residual solution after adsorption (mg / L); substrate ventilation volume (maximum volume oxygen content per square meter of substrate, unit m 3 / m 2 ), and each treatment was repeated three times to take the average value.

[0136] Table 3 Effects of different soil formulations on substrate ventilation and lead removal rate

[0137]

[0138]

[0139] Test results:

[0140] The test of the influence of different guest soil formulas on the ventilation volume and lead removal rate of the matrix in the present application shows that the formula of the bottom matrix + surface matrix of Example 1 has the highest lead removal rate, up to 95%. By rationally matching the two materials and adjusting the particle size, the matrix ventilation volume suitable for plant cultivation is achieved. By comparing the test of using a single layer of guest soil matrix, it can be seen that two layers of matrix can have the best lead removal rate and matrix ventilation volume. In addition, the thickness of the guest soil also affects the above two indicators. When the thickness of the guest soil matrix decreases, its heavy metal removal rate and ventilation volume also decrease accordingly, which is not conducive to the recovery and growth of vegetation. The addition of corn stalk segments and rice husks to the guest soil spraying can not only increase friction and reduce soil erosion, but also have the effect of increasing the ventilation volume of the matrix. Without adding any of the above substances, the amount of heavy metal adsorption and ventilation volume of the guest soil formula composed of them will be significantly reduced. The volume ratio and particle size ratio of polystyrene foam and polyacrylamide will affect the lead metal removal rate and matrix ventilation of the guest soil formula mechanism. The combined use of these two soil conditioners can enable the guest soil matrix to form a light and well-bonded granular structure, which is not prone to soil erosion. It has good agglomeration and good ventilation, providing a good growth environment for plant growth on the guest soil matrix.

[0141] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for ecological restoration of mine slopes, characterized in that: The method involves using a combination of slow-release water-retaining fertilizer and imported soil spraying matrix in conjunction with plants to repair heavy metal-contaminated mine slopes. The slow-release water-retaining fertilizer is a mixture of 3mm humic acid granular fertilizer, 8mm humic acid granular fertilizer, 5mm polyacrylamide granular particle size, 10mm polyacrylamide granular particle size, slow-release urea, and sodium carboxymethyl cellulose powder, in a volume ratio of 5:3:2:1:2:

1. The imported soil spraying matrix includes the bottom matrix and the surface matrix. The bottom matrix is ​​an ecological concrete structure matrix, including: planting soil, cement, 8cm corn stalks, rice husks, decomposed livestock manure, 3mm polystyrene foam particles, and 10mm polyacrylamide, and the above raw materials are mixed in a volume ratio of 8:0.5:2:1:1.5:0.5:0.5; The surface matrix is ​​an ecological restoration layer matrix, comprising: planting soil, 3cm corn stalk segments, rice husks, decomposed livestock manure, 3mm polystyrene foam particles, and 5mm polyacrylamide; the above raw materials are mixed in a volume ratio of 8:3:1:2:1:1; The spraying dosage of soil remediation plant seeds is 7-8g / m 2 The soil remediation plant seeds are a mixture of Dianthus superbus, Psoralea corylifolia and Scutellaria baicalensis in a weight ratio of 3:2:

1.

2. The method according to claim 1, wherein The following steps are also included: (1) Leveling and repairing the area Use machinery and manual labor to trim the ground in the repair area, remove debris, backfill depressions, level the ground and compact it to ensure there is no looseness; If there is a native topsoil layer in the restoration area, the topsoil should be collected and sieved for impurities and used as planting soil for later vegetation restoration and reconstruction; If native trees and shrubs exist in the restoration area, they should be transplanted and replanted during the later vegetation restoration and reconstruction. (2) Slope construction in the repair area Drill holes and install steel bars every 0.5-1m along the slope surface. The hole depth is 40-50cm and the steel bar diameter is 12-14mm. The steel bars are exposed 5-10cm above the slope surface for surface mesh hanging. (3) Installation of anti-slip slow-release eco-bags On the steel bars of the slope, anti-skid slow-release eco-bags are fixedly installed. The anti-skid slow-release eco-bags are cylindrical bag-shaped objects with a diameter of 7-10 cm and a length of 1-2 m. They are made of biodegradable materials and are pre-filled with slow-release water-retaining fertilizers. The bag material slowly releases nutrients and can also store rainwater and provide moisture for plant growth. Each bag has a linking device at both ends, so that multiple bags can be connected and fixed horizontally on the slope. During installation, a horizontal groove is first opened on the slope, the size of which can accommodate the anti-skid slow-release eco-bag. The bag is then stuck in the horizontal groove on the slope and supported and fixed with steel bars. At the same time, the connection between each bag is also fixed to the slope with a fixing device. The horizontally installed anti-skid slow-release eco-bag can not only increase friction to prevent the soil on the slope from sliding, but also provide long-term nutrients and moisture for plant growth. (4) Hanging mesh construction Lay galvanized wire mesh according to the slope surface and fix it with wire ties and steel bars on the slope surface. When hanging the mesh, the mesh surface should be as close to the slope surface as possible. The mesh size of the galvanized wire mesh is 5cm×5cm and the diameter is 2mm. (5) Imported soil spraying matrix The imported soil spraying matrix includes the bottom matrix and the surface matrix. (6) Spray seeding construction For bottom matrix spraying, mix the selected ecological concrete structure matrix materials evenly, and use a mud machine to spray evenly on the slope surface with mesh, with a thickness of 10-15cm; Spraying the surface matrix, mix the raw materials of the ecological restoration layer matrix evenly, and use a mud machine to spray evenly on the bottom matrix, with a thickness of 8-12cm; Seed spraying: put the soil remediation plant seeds into the sprayer, add water and mix evenly, and spray them on the surface substrate through a pressurized pipe; After the spraying is completed, cover the surface with a layer of non-woven fabric and fix the non-woven fabric on the slope with bamboo sticks; when it is dry, water it thoroughly.

3. The mine ecological restoration method according to claim 2, characterized in that: The planting soil includes the original topsoil layer of the restoration area in step (1), and / or soil sources selected nearby the restoration area, and / or soil sources transported from other places. When taking soil from the soil sources selected nearby the restoration area, the surface humus layer should be dug and piled nearby for proper preservation. After the soil is taken, the surface humus layer should be re-laid and vegetation should be added to prevent soil erosion.

4. The mine ecological restoration method according to claim 2, characterized in that: It also includes the steps of spot planting and greening after seed spraying, specifically: After the spraying of soil remediation plant seeds is completed, artificial sowing of tree and shrub seedlings is carried out. Trees, shrubs and greening are arranged according to a certain planting area ratio to achieve the best horizontal coverage, and the vertical structure of the community is reasonable and the ornamental value is strong; For the first sowing, the seedlings of Cinnamomum camphora, Rhus chinensis, Liquidambar formosana, Sapium sebiferum, Casuarina equisetifolia, and Paulownia are mixed, with a sowing density of 6-10 seeds / m 2 ; The second sowing: oleander, Amorpha fruticosa, Lespedeza, Cassia corymbosa, Indigofera chinensis, and seedlings are mixed in equal numbers; the sowing density is 15-20 seeds / m 2 .

5. The mine ecological restoration method according to claim 2, characterized in that: It also includes maintenance and management steps after seed spraying, specifically: After spraying, the maintenance period begins. Water is sprayed every day from 8 to 10 am and from 4 to 6 pm to ensure that the slope surface remains moist and does not produce surface runoff. 5g / m2 of water-soluble compound fertilizer with an N:P:K ratio of 10:20:10 is applied every week. 2 , until the seeds germinate and form a complete cover.

6. The mine ecological restoration method according to claim 2, characterized in that: One month after sowing, spray a mixed solution of potassium dihydrogen phosphate with a mass concentration of 0.5-1.0% and melatonin with a concentration of 80-100 μM / L. The mixed solution is prepared by first preparing each solution of the above concentration separately and then mixing them in equal volume ratios. Spray it with water between 4 and 6 pm and continue spraying for 3 consecutive days.

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