Artificial sowing combined with surface crust ecological restoration method for mine slope in northern wind erosion region

Abstract

The application discloses a kind of northern wind erosion area mine slope artificial sowing combined surface crust ecological restoration method, utilize the soil-like substrate formed in the process of mine development, simulate natural soil structure, large-diameter soil-like substrate is spread to the bottom layer of tillage layer, small-diameter substrate is spread to surface layer, while surface layer substrate is mixed with a small amount of guest soil and various fertilizers, stratified construction tillage layer soil layer, meet the index requirement required for seed germination and growth.Surface crust is sprayed from three aspects of matrix fertilization, water conservation, crust water conservation and so on, which can ensure the normal germination of plants and prevent wind erosion.According to the wind erosion wind power and seed germination, the principles of vegetation reconstruction species selection, combination of shrubs and grasses, combination of legumes and grasses, combination of perennials and annuals, combination of taproot system and fibrous root system, combination of pioneer species and constructive species, plant selection and proportioning are carried out to increase species diversity and reduce the risk of diseases and pests.

Description

Technical Field

[0001] This invention relates to the field of environmental protection and ecological restoration technology, specifically to an ecological restoration method for mine slopes in wind-eroded areas of northern China that combines artificial seeding with surface crusting. Background Technology

[0002] In the wind-erosion areas of the north, the average annual precipitation is around 190 mm, while the evaporation reaches 2700 mm. The average annual wind speed is 4.5 m / s, and the soil erosion modulus is 2600 t / km². 2 •a. In existing mine ecological restoration processes, slopes with a gradient of 33 degrees or more are generally restored using topsoil spraying; slopes with a gradient of less than 33 degrees are generally restored using manual seeding.

[0003] Hydroseeding technology, due to the presence of a certain proportion and quantity of mulch, adhesive, seeds, and other components, can form a uniformly distributed seed film on the soil surface after hydroseeding. This effectively prevents rainwater erosion and seed loss, resulting in uniform and neat vegetation with good results. However, its construction cost is relatively high.

[0004] Manual seeding is simple to operate, easy to construct, low in cost, and relatively effective. However, in areas with severe wind erosion or when encountering strong winds during the seedling stage, it can easily cause wind erosion of the slope soil, resulting in poor restoration effects. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a method for ecological restoration of mine slopes in wind-eroded areas of northern China, combining artificial seeding with surface crusting.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The ecological restoration method for mine slopes in wind-eroded areas of northern China, which combines artificial seeding with surface crusting, includes the following steps:

[0008] S1. Terrain trimming:

[0009] S1.1 Slope cleaning: Treat the uneven parts of the construction slope. Use a bulldozer to push soil to fill the concave parts and use an excavator to level the convex parts, so that the entire slope surface is flat and contains loose, active soil; clean up the debris on the slope surface.

[0010] S1.2 Constructing a water-retaining cofferdam: Constructing a water-retaining cofferdam and supporting drainage facilities at the top of the construction slope;

[0011] S2. Construction and improvement of the topsoil layer:

[0012] S2.1 Construction of the topsoil layer: After compacting, crushing and screening the soil matrix, the soil matrix with larger particle size is filled into the lower part of the topsoil layer; the soil matrix with smaller particle size is filled into the upper part of the topsoil layer, thus forming the topsoil layer.

[0013] S2.2 Improve the soil-like substrate on the surface of the tillage layer: A soil-like substrate that meets the growth requirements of plants is laid on the surface of the soil layer of the tillage layer constructed in step S2.1 to form the surface layer of the tillage layer, and planting soil, organic fertilizer and multi-element ecological fertilizer are mixed into the soil-like substrate used on the surface layer.

[0014] S3. Vegetation establishment: Select suitable plant varieties for local ecological restoration and mix them, then manually sow them on the cultivated layer constructed in step S2 to establish vegetation.

[0015] S4. Laying straw mats: Select straw mats made primarily of rice straw for laying.

[0016] S5. Spraying on the surface crust:

[0017] First, apply fertilizer: mainly microbial agents, slow-release fertilizers, and water-soluble fertilizers to achieve rapid fertilization of the substrate;

[0018] Then water to retain moisture: This watering should be thorough and repeated multiple times to increase the soil moisture content and leach the fertilizer applied in the first spray to a depth of 2-10cm on the soil surface.

[0019] Subsequently, a surface crusting material is sprayed: a mixture of polyethylene dust suppressant, quicklime, and greening water is prepared to form the surface crusting material. The spraying thickness should ensure that the plants can germinate and emerge from the soil normally, while also preventing wind erosion. Depending on the wind and climate conditions and seed germination, if the material is sprayed too thickly, water can be applied when the seeds are germinating in large quantities to aid in the decomposition of the material, which helps the seeds break through the soil and germinate, and also acts as a water-retaining agent to improve soil moisture. If the material is sprayed too thinly, re-spraying measures should be taken to achieve the effects of resisting wind erosion, conserving soil moisture, promoting soil breaking, and facilitating germination.

[0020] S6. Watering and maintenance.

[0021] Furthermore, in step S1.2, the water-retaining cofferdam is trapezoidal, and the earthen embankment is trimmed to be continuous and not too low or too high.

[0022] Further, in step S2.1, the selected soil-like substrate with a particle size ≥ 5 cm is filled into the lower part of the tillage layer to form a thickness of 20-25 cm; soil-like substrate with a particle size ≤ 2 cm is selected and filled into the upper part of the tillage layer to form a thickness of 10-15 cm.

[0023] Furthermore, in step S2.2, the soil-like matrix used in the surface layer has a particle size ≤1cm.

[0024] Furthermore, in step S3, manual sowing and rakeing are carried out at a sowing rate of 25-45g per square meter. The sowing rate on the upper part of the slope is controlled at 45g per square meter, and the sowing rate on the lower part of the slope is controlled at 25g per square meter to ensure uniform germination and no obvious bald spots.

[0025] Furthermore, in step S3, the selected plant varieties include shrubs and trees, legumes, grasses, wild leeks, and wild onions. The shrubs and trees include elms and caragana, the legumes include alfalfa and saxaul, and the grasses include sheepgrass, awnless bromegrass, crested wheatgrass, and old awned wheatgrass. The mass ratio of elm:caragana:alfalfa:saxaul:sheepgrass:awnless bromegrass: crested wheatgrass: old awned wheat: wild leeks: wild onions is 20:20:12:3:4:3:2:1:1:1.

[0026] Furthermore, after sowing, sowing compaction is carried out.

[0027] Further, in step S4, when the slope length is less than 20 meters, 10-meter-long / roll straw mats are selected for laying; when the slope length is more than 20 meters, 20-25-meter-long / roll straw mats are selected for laying, and the width of the straw mats is 1.5 meters. When planting monocotyledonous plants on the slope, straw mats weighing 220-250g per square meter are selected; when planting dicotyledonous plants on the slope, straw mats weighing 200-230g per square meter are selected; when planting mixed plants on the slope, straw mats weighing 200-230g per square meter are recommended. The straw mats are soaked for 2-8 hours before use. The straw mats are laid from the bottom inside the water-retaining embankment at the top of the slope, and the overlaps of the straw mats should face the direction of the monsoon wind to prevent the straw mats from being blown away by the monsoon wind, and the straw mats are fixed with fasteners.

[0028] Furthermore, in step S5, the polyethylene oxide dust suppressant, quicklime, and greening water are mixed in a mass ratio of 1:2:50; the material spraying thickness is 5 mm.

[0029] Furthermore, in step S6, depending on the soil moisture level, the watering time should not be too long to prevent soil erosion; in windy spring weather, watering should be done in the early morning, and in summer, watering should be done in the early morning or evening; the watering frequency should be adjusted according to changes in climate, soil, and season.

[0030] The beneficial effects of this invention are as follows: This invention combines artificial sowing of vegetation on mine slopes with sandy soil substrate improvement and surface crusting technology. This ensures that the sandy soil substrate on the windward side of mine slopes in windy and sandy areas is not eroded by wind, and also ensures that seeds receive sufficient nutrients and water during germination, thus playing a role in fertilizer retention, water retention, and moisture retention. This invention can significantly improve seed germination rate and seedling survival rate after sowing, while controlling wind erosion and topsoil loss. Specifically:

[0031] 1. Constructing a topsoil layer and enhancing fertility using soil-like substrates: Utilizing soil-like substrates (weathered mudstone powder, sandstone powder, etc.) formed during mining operations, a natural soil structure is simulated. Large-particle soil-like substrate is spread at the bottom of the topsoil layer, while small-particle substrate is spread on the surface. Simultaneously, the surface substrate is mixed with a small amount of imported soil and various fertilizers to construct a layered topsoil layer that meets the requirements for soil structure, soil microorganisms, soil salinity, soil pH, and various nutrients necessary for seed germination and growth. This reduces the amount of imported soil used while achieving waste utilization and waste-to-resource conversion.

[0032] 2. Surface crust spraying: Surface crust spraying is carried out in three stages: substrate fertilization, watering to retain moisture, and crusting to retain water. This ensures that plants can germinate and break through the soil normally, while also preventing wind erosion.

[0033] 3. Native plant configuration: The selection and matching of species for vegetation reconstruction should follow the principles of combining trees, shrubs and grasses, legumes and grasses, perennials and annuals, taproots and fibrous roots, and pioneer species and community-building species to increase species diversity and reduce the risk of pests and diseases. Detailed Implementation

[0034] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to this embodiment.

[0035] This embodiment provides a method for ecological restoration of mine slopes in wind-eroded areas of northern China, combining artificial seeding with surface crusting. It is primarily applicable to areas with an average annual precipitation of approximately 190 mm, evaporation of up to 2700 mm, an average annual wind speed of 4.5 m / s, and a soil erosion modulus of 2600 t / km². 2 • The mining slopes in the northern wind-eroded areas of region a specifically include the following steps:

[0036] S1. Terrain shaping: This mainly includes slope clearing and the construction of water-retaining cofferdams.

[0037] S1.1 Slope Cleaning: Treat the uneven parts of the construction slope. Use a bulldozer to push soil up the concave parts and use an excavator to level the convex parts to make the entire slope surface flat and leave loose soil on the slope surface to facilitate subsequent processes. Clean up the debris on the slope surface and pile it at the foot of the slope for unified disposal later.

[0038] S1.2 Constructing a water-retaining cofferdam: Constructing a water-retaining cofferdam and supporting drainage facilities on the top of the construction slope. The water-retaining cofferdam is generally trapezoidal. In this embodiment, the top of the water-retaining cofferdam is 1 meter long, the bottom is 2 meters long, and the height is 1 meter. The earthen embankment is made continuous and does not have excessively low or high phenomena, which can prevent soil erosion and achieve aesthetic effects.

[0039] S2. Construction and improvement of the topsoil layer:

[0040] Because the original surface soil of the mine slope is insufficient and the source of imported soil is difficult, this embodiment makes full use of the soil-like matrix formed by the weathering of mudstone powder and sandstone powder to construct the topsoil layer and improve the soil.

[0041] S2.1 Constructing the topsoil layer (i.e., the base layer in the topsoil): After compacting, crushing, and screening the soil matrix, fill the lower part of the topsoil layer with larger particle sizes (diameter ≥ 5cm) to form a thickness of 20-25cm; to meet planting needs, select smaller particle sizes (diameter ≤ 2cm) to fill the upper part of the topsoil layer to form a thickness of 10-15cm, thus forming the topsoil layer;

[0042] S2.2 Improve the surface soil-like matrix of the tillage layer: A soil-like matrix suitable for plant growth is laid on the surface of the soil layer of the tillage layer constructed in step S2.1, with a thickness of 10-15cm, to form the surface layer of the tillage layer; the particle size of the soil-like matrix used in the surface layer is ≤1cm, and a small amount of planting soil (such as loess), organic fertilizer (or farmyard manure) and multi-element ecological fertilizer (multi-nutrient mixed fertilizer, microbial fertilizer, soil remediation agent) are mixed in the soil-like matrix used in the surface layer. The mass ratio of planting soil, organic fertilizer and multi-element ecological fertilizer is 100:10:1, which can improve the soil fertility of the surface soil-like matrix.

[0043] Specifically, spread the mixture of planting soil, organic fertilizer, and multi-element ecological fertilizer at a rate of 6 to 12 cubic meters per acre, and mix it evenly with the soil-like substrate used on the surface, so that the fertilization capacity reaches the medium level of the relevant ecological restoration soil standards.

[0044] S3. Vegetation establishment (artificial sowing): Select suitable plant varieties for local ecological restoration and mix them, then manually sow them on the cultivated layer constructed in step S2 to establish vegetation.

[0045] S3.1 Sowing: Sow manually at a rate of 25-45g per square meter. Control the sowing rate at about 45g per square meter on the upper part of the slope and at about 25g per square meter on the lower part of the slope to ensure uniform germination and no obvious bald spots.

[0046] Plant selection should be based on the results of field surveys. In this embodiment, the selected plant varieties include shrubs and trees, legumes, grasses, wild leeks, and wild onions. The shrubs and trees include elms and caragana, the legumes include alfalfa and saxaul, and the grasses include sheepgrass, awnless bromegrass, crested wheatgrass, and old awned wheatgrass. The mass ratio of elm: caragana: alfalfa: saxaul: sheepgrass: awnless bromegrass: crested wheatgrass: old awned wheatgrass: wild leeks: wild onions is 20:20:12:3:4:3:2:1:1:1.

[0047] S3.2 Post-sowing compaction: This can be done using a professional compactor or a compactor consisting of multiple compaction rollers. The rollers have a diameter of 40-70cm, and each roller can rise and fall automatically according to the terrain, adjusting the compaction intensity. If compaction easily causes surface soil compaction, mechanical compaction can be omitted, and instead, spraying can be used to settle the surface soil.

[0048] S4. Laying straw mats. Based on the characteristics of mine ecological restoration, straw mats with rice straw as the main material are selected. The length and width of the straw mats are customized according to the slope length, and the density of the straw mats is customized according to the plant varieties to be sown.

[0049] It should be noted that, for straw mats, reed mats are relatively hard, absorb less water which is not conducive to moisture retention, decompose slowly which is not conducive to material cycling, and their hard texture is not conducive to seed germination and penetration. Therefore, straw is the preferred material for straw mats.

[0050] Specifically, when the slope length is less than 20 meters, use straw mats that are 10 meters long per roll for laying; when the slope length is more than 20 meters, use straw mats that are 20 to 25 meters long per roll for laying. Rolls that are too long are inconvenient for construction, while rolls that are too short result in excessive overlap and wastage.

[0051] More specifically, since each straw is generally about 1.5 meters long, it is advisable to choose a straw mat width of 1.5 meters. A 2-meter wide straw mat is prone to quality problems such as tearing in the middle due to excessive overlapping of straws during production. While a 1.3-meter wide straw mat is of better quality, the overlap of each piece results in excessive waste when used over a large area.

[0052] Specifically, when planting monocotyledonous plants on slopes, it is advisable to select straw mats weighing 220-250g per square meter; when planting dicotyledonous plants on slopes, it is advisable to select straw mats weighing 200-230g per square meter; and when planting mixed plants on slopes, it is advisable to select straw mats weighing 200-230g per square meter, so as to balance cost and effect.

[0053] Specifically, due to the strong winds at the top of the slope, the straw mats must be soaked for 2-8 hours before use. Soaking increases the weight of the straw mats, which is beneficial for laying, and at the same time, increasing the water content can improve soil moisture, which is conducive to the germination of plant seeds.

[0054] More specifically, the straw mats should be laid starting from the bottom of the inner side of the water-retaining dike at the top of the slope. The overlaps of the straw mats should face the monsoon winds to prevent them from being blown away. Use No. 8 iron wire to secure the straw mats, cutting the wire into 30-40cm sections and bending each section into a U-shape. Insert the U-shaped wire into the soil, securing it every 2-3 meters. Increase the density of insertions on the windward side and at the overlaps. The overall density should be such that the straw mats are not blown away by the wind. Simultaneously, during the laying of the straw mats and other processes, promptly re-sow any seeds lost due to footprints left by workers on the slope. U-shaped wires can also be replaced with readily available U-shaped nails.

[0055] S5. Spraying on the surface crust:

[0056] First, apply fertilizer: mainly microbial agents, slow-release fertilizers, and water-soluble fertilizers to achieve the purpose of rapid fertilization of the substrate.

[0057] Then water to retain moisture: This watering should be thorough, but the water should not be allowed to flow into columns on the slope, causing surface soil erosion. Therefore, it is necessary to spray repeatedly to increase the soil moisture content and leach the fertilizer applied in the first spray to a depth of 2-10cm on the ground surface. This is beneficial for plant roots to utilize the fertilizer. While replenishing the water needed for seed germination, the fertilizer is also leached downwards to better exert its fertilizer effect.

[0058] Subsequently, a surface crusting material is sprayed: an eco-friendly dust suppressant is used as the main crusting material, with quicklime added. This changes the composition of the dust suppressant while reducing costs and increasing effectiveness. In this embodiment, the eco-friendly dust suppressant is a polyethylene oxide dust suppressant. The polyethylene oxide dust suppressant, quicklime, and greening water are mixed in a mass ratio of 1:2:50 to obtain the surface crusting material. The spraying thickness is about 5 mm, ensuring that plants can germinate and emerge from the soil normally while preventing wind erosion. Depending on wind and climate conditions and seed germination, if the material is sprayed too thickly, water can be applied when the seeds are germinating in large quantities to aid in material decomposition and promote seed emergence. The material also has a water absorption capacity of 5-100 times its own weight, acting as a water-retaining agent to improve soil moisture. If the material is sprayed too thinly, re-spraying can be carried out to achieve the effects of wind erosion resistance, soil moisture retention, promoting soil emergence, and facilitating germination.

[0059] S6. Watering and maintenance:

[0060] Depending on the soil moisture level, watering time should not be too long, and soil erosion must be strictly prevented.

[0061] In windy spring weather, try to water in the early morning to significantly reduce wind erosion of the topsoil. In summer, water in the early morning or late evening. Watering at midday in summer can cause a sudden drop in soil temperature, which can irritate the plant roots and prevent them from absorbing water properly.

[0062] The frequency of watering needs to be adjusted according to changes in climate, soil, and season. In the early stages of vegetation establishment, watering is required 1-2 times a day. After the seedlings emerge, watering can be done once every 2-3 days.

[0063] For those skilled in the art, various corresponding changes and modifications can be made based on the above technical solutions and concepts, and all such changes and modifications should be included within the protection scope of the claims of this invention.

Claims

1. A method for ecological restoration of mine slopes in the northern wind erosion region by artificial sowing combined with surface crust, characterized in that, It comprises the following steps: S1, terrain modification: S1.1, slope cleaning: processing the concave and convex parts of the construction slope, filling the concave parts with a shovel, and hooking the convex parts with a hook machine to make the entire slope flat, so that the slope has soft and loose soil; clean the slope debris; S1.2, build a water retaining cofferdam: build a water retaining cofferdam and supporting drainage facilities on the top of the construction slope; S2, construction of the plough layer and improvement: S2.1, construction of the soil layer of the plough layer: after crushing, pulverizing and screening the soil matrix, the soil matrix with a particle size of ≥5 cm is filled into the lower part of the plough layer to construct a thickness of 20-25 cm; select the soil matrix with a particle size of ≤2 cm to fill into the upper part of the plough layer to construct a thickness of 10-15 cm, thereby forming the soil layer of the plough layer; S2.2, improvement of the surface layer of the plough layer: lay the soil matrix suitable for plant growth on the surface of the soil layer of the plough layer constructed in step S2.1 to form the surface layer of the plough layer, and mix planting soil, organic fertilizer and multi-element ecological fertilizer in the soil matrix used in the surface layer; S3, vegetation construction: select plant species suitable for local ecological restoration and proportion them, then manually sow and rake on the plough layer constructed in step S2, with a seeding amount of 25-45 g per square meter, the seeding amount on the upper part of the slope is controlled at 45 g per square meter, and the seeding amount on the lower part of the slope is controlled at 25 g per square meter, to construct vegetation; the selected plant species include inner arbor and shrub plants, legume plants, grass plants, mountain leeks and mountain onions, the inner arbor and shrub plants include elm and caragana, the legume plants include alfalfa and siberian wildrye, and the grass plants include Leymus chinensis, Bromus inermis, Elymus dahuricus and Elymus nutans; The mass ratio of elm: caragana: alfalfa: siberian wildrye: Leymus chinensis: Bromus inermis: Elymus dahuricus: Elymus nutans: mountain leek: mountain onion is 20:20:12:3:4:3:2:1:1:1; S4, laying of straw curtain: select rice straw curtain as the main material for straw curtain laying, select 200-230 g of straw curtain per square meter when planting dicotyledonous plants on the slope, and select 200-230 g of straw curtain per square meter when planting mixed plants on the slope; S5, surface crust spraying: First, spray fertilizer: mainly spray microbial agent, long-acting slow-release fertilizer and water-soluble fertilizer to realize rapid fertilization of the matrix; Then, water conservation: this time, water should be poured thoroughly, which needs to be sprayed repeatedly to improve the soil moisture content and leach the fertilizer sprayed in the first pass to the ground surface 2-10 cm. After spraying the surface layer of the material: the polyethylene oxide dust suppressant, lime and water mixed to get the surface layer of the material, the thickness of the spray to ensure that the plant can germinate and break out, but also to prevent wind erosion; according to the wind climate and seed germination, if the material is sprayed too thick, can be watered when the seed germination, auxiliary material decomposition, help seed germination and break out, and play the role of water retention agent, improve the soil; if the material is sprayed too thin, re-spraying measures to achieve wind erosion, soil conservation, promote the effect of breaking the soil, the seed germination; polyethylene oxide dust suppressant, lime and water according to the mass ratio of 1:2:50; material spray thickness of 5mm; S6, watering maintenance.

2. The method of claim 1, wherein, In step S1.2, the water retaining cofferdam is trapezoidal, and the soil ridge is trimmed to be continuous and not too low or too high.

3. The method of claim 1, wherein, In step S2.2, the particle size of the soil matrix used in the surface layer is ≤1cm.

4. The method of claim 1, wherein, After sowing, the sowing is pressed.

5. The method of claim 1, wherein, In step S4, when the slope length is less than 20 meters, a 10-meter-long / roll grass curtain is selected for laying, and when the slope length is more than 20 meters, a 20-25-meter-long / roll grass curtain is selected for laying, and the width of the grass curtain is 1.5 meters; when monocotyledonous plants are planted on the slope, 220-250g of grass curtain per square meter is selected; the grass curtain is soaked for 2-8 hours before use; the grass curtain is laid from the inside bottom of the water retaining cofferdam at the top of the slope, and the grass curtain is overlapped in the direction of the monsoon to prevent the grass curtain from being blown up by the monsoon, and the grass curtain is fixed by a fixing member.

6. The method of claim 1, wherein, In step S6, the watering time should not be too long according to the dry and wet conditions of the soil to prevent water and soil loss; in spring, try to choose to water in the morning, and in summer, try to choose to water in the morning and evening; the watering frequency needs to be adjusted according to the changes of climate, soil and season.