Desert mining area coal gangue mountain soil improvement and vegetation reconstruction method

Abstract

The invention provides a desert mining area coal gangue mountain soil improvement and vegetation reconstruction method, and belongs to the technical field of coal mine area ecological restoration. According to the invention, a technical system comprising three stages of pretreatment, composite improvement and vegetation planting is constructed, and a desert region winter snowfall resource, a physical-chemical synergistic water retention material and a localized sheep manure resource are innovatively coupled: snow water is used for infiltration through a time sequence design, so that the slow-release fertilizer efficiency of sheep manure and the water storage function of the water retention material are activated; the lignocellulose in the water-retaining material is compounded and proportioned with two cellulose ethers, so that the synergistic interaction of physical pore water retention and chemical gel water retention is realized; the local sheep manure is simultaneously used as a carrier of the slow-release fertilizer and the local grass seeds, so that the ecological suitability is greatly improved, and the cost is reduced; the unique contour line furrow and double-layer covering structure effectively achieves microtopography water collection and soil moisture conservation and evaporation reduction, finally achieves rapid, low-cost and high-survival-rate vegetation reconstruction and ecological restoration, and is particularly suitable for large-scale engineering application.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology in coal mining areas, and more specifically, to a method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas. Background Technology

[0002] Coal gangue piles are the main solid waste accumulations from coal mining. In arid mining areas, vegetation reconstruction of coal gangue piles faces three major technical challenges: First, the soil is scarce and of extremely poor quality: the topsoil is mostly weathered debris from gangue, containing a large amount of gravel with a particle size >3cm, resulting in poor soil pore structure and near-zero water and fertilizer retention capacity. Second, the arid environment restricts vegetation survival: arid regions have scarce rainfall and strong evaporation; traditional improvement methods, such as simply applying fertilizer or laying soil, cannot solve the core contradiction of "rapid water loss and easy nutrient leaching." Third, the lack of a soil seed bank and poor vegetation compatibility: the weathered debris covering the gangue lacks grass species, introduced grass species lack sufficient stress resistance, and local vegetation lacks targeted cultivation carriers, leading to low survival rates and poor stability of reconstructed vegetation.

[0003] In existing technologies, soil improvement often adopts a "deep summer plowing + fertilizer application" model, failing to utilize winter snowfall resources in desert areas. Water conservation measures are mostly limited to the simple use of straw or single water-retaining agents, failing to form a synergistic effect of "physical water retention + chemical water locking," resulting in weak water retention capacity. Vegetation faces severe water stress during critical growth periods, leading to low germination and survival rates. Vegetation reconstruction does not combine the dual functions of local sheep manure as a "fertilizer carrier + grass seed carrier," requiring the purchase of external fertilizers and water-retaining materials. Furthermore, due to rapid water and nutrient loss, multiple applications and irrigations are often necessary. Moreover, the established vegetation communities have a simple structure, shallow and weak root systems, and poor resilience. Once human intervention weakens, the ecosystem is prone to degradation or even collapse, making it difficult to maintain the restoration results stably.

[0004] Therefore, there is an urgent need to develop a method for soil improvement and vegetation reconstruction in desert mining areas that can achieve efficient integration of soil improvement and vegetation restoration. Summary of the Invention

[0005] This invention aims to solve the soil structure problems of coal gangue hills in desert mining areas, which are characterized by soil deficiency, infertility, and excessive gravel. By constructing a "loose-water-retaining-long-lasting fertility" soil environment, and utilizing the synergistic effect of winter snowfall and water-retaining materials, it solves the water retention problem in arid areas and reduces the dependence on vegetation irrigation. By combining local materials (sheep manure, local grass species) with stress-resistant mixed grass species, it improves the survival rate of vegetation and ecological stability. The invention also simplifies the operation process, reduces the improvement cost, and enables large-scale application.

[0006] To achieve the above objectives, this invention provides a method for soil improvement and vegetation reconstruction in coal gangue hills in desert mining areas, comprising the following steps: S1. Pretreatment stage: 10-15 days after the onset of winter and before snowfall (usually mid-to-late November in desert areas). At this time, the soil is not frozen, which is convenient for mechanical operations. After snowfall, the soil can be naturally moistened to activate the fertilizer effect of sheep manure. Loosen the topsoil covering the coal gangue mountain and remove gravel with a particle size ≥3cm to avoid affecting root growth and the distribution of water-retaining materials. Then, use a harrow to level the loosened topsoil to prevent water loss after snowfall. S2, Composite Improvement Stage: Fermented sheep manure (using local sheep manure) is evenly spread on the pretreated surface and mixed with the shallow topsoil by rotary tillage with a micro-tiller to form a "manure-soil" composite improvement layer, which improves the soil pore structure and slowly releases nutrients; then, furrow planning is carried out along the preset direction, and the fermented sheep manure carrying local grass seeds is spread along the planned direction. S3. Vegetation planting stage: Dig furrows along the planned direction of the furrows to avoid soil erosion; spread composite water-retaining material evenly at the bottom of the furrows; sow stress-resistant mixed grass seeds on the composite water-retaining material; first, use the first mulch material to evenly cover the grass seeds, and then use the second mulch material to cover them to form the furrow planting layer. The composite water-retaining material is composed of lignocellulose, carboxymethyl cellulose (CMC), and hydroxypropyl methyl cellulose (HPMC) in a mass ratio of 1:1:1; the first covering material is composed of fermented sheep manure and high-quality topsoil in a volume ratio of 1:1. Lignocellulose provides physical pores for water retention, while CMC and HPMC form a chemical gel to lock in water. The three materials work synergistically to improve the soil water holding capacity by ≥30%; the second covering material is high-quality topsoil.

[0007] As a further description of the above technical solution, in S1 above, a micro-tiller with a power of ≥15kW is used to perform loosening operations at a depth of 0-15cm.

[0008] As a further description of the above technical solution, in S2 above, the amount of fermented sheep manure initially spread is 1.5-2.0 kg / m², and the rotary tillage depth is 8-10 cm.

[0009] As a further description of the above technical solution, in S2 above, the preset direction of the furrow planning is along the contour line of the gangue hill, and the furrow spacing is 0.5m.

[0010] As a further description of the above technical solution, in S2 above, the amount of fermented sheep manure carrying local grass seeds spread is 0.8-1.0 kg / m², wherein the amount of local grass seeds naturally mixed in is ≥50 grains / m².

[0011] As a further description of the above technical solution, in S3 above, the specifications of the excavated furrows are: furrow width 5-15cm, furrow depth 15-20cm.

[0012] As a further description of the above technical solution, in S3 above, the amount of the composite water-retaining material spread is 0.3-0.5 kg / m²; the stress-resistant mixed grass seeds include Elaeagnus pungens, tall fescue, Suaeda salsa, and ryegrass, with a sowing rate of 15-20 g / m², which is suitable for arid desert and saline-alkali soil environments; the first covering material has a covering thickness of 1 cm, which not only keeps the soil warm and fertile but also does not bury the grass seeds, ensuring the germination rate; the second covering material has a covering thickness of 1 cm, and the second covering material is placed on top of the first covering material, and high-quality topsoil is spread to form a "ridge-furrow planting layer" to prevent the water-retaining material and grass seeds from being blown away by the wind.

[0013] As a further description of the above technical solution, the preparation method of the fermented sheep manure includes: composting and fermenting sheep manure (sheep manure raised around desert mining areas can be selected), with a fermentation cycle of 45-60 days, turning the pile every 7-10 days during the fermentation period, and naturally drying it until the moisture content is ≤20% after fermentation is completed.

[0014] The present invention also provides a composite water-retaining material for the soil improvement and vegetation reconstruction method of coal gangue hills in desert mining areas, which is composed of lignocellulose, carboxymethylcellulose and hydroxypropylmethylcellulose mixed in a mass ratio of 1:1:1.

[0015] This invention also provides a ridge-furrow structure for vegetation reconstruction of coal gangue hills constructed using the aforementioned method for soil improvement and vegetation reconstruction in desert mining areas, comprising, from bottom to top: The composite water-retaining material layer is composed of lignocellulose, carboxymethylcellulose and hydroxypropylmethylcellulose mixed in a mass ratio of 1:1:1. Grass seed layer; The first covering layer is made of fermented sheep manure and high-quality topsoil mixed in a 1:1 volume ratio, and the covering thickness is 1cm. The second cover layer is made of high-quality topsoil and has a thickness of 1 cm.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention constructs a sustainable remediation technology system adapted to arid and semi-arid coal mining areas, breaking through the dependence of traditional remediation on artificial irrigation. It pioneers a three-element winter synergistic mechanism of "snowfall-sheep manure-water-retaining materials", which utilizes natural water resources from winter snowfall and combines the slow decomposition characteristics of sheep manure under low temperature conditions to achieve simultaneous storage of nutrients and water.

[0017] 2. By constructing a three-dimensional porous structure using lignocellulose to lock in gravity water, and by forming a polymeric gel network with carboxymethyl cellulose and hydroxypropyl methyl cellulose to adsorb capillary water, the synergistic effect extends the soil water retention time to 45-60 days, solving the problem of vegetation water shortage caused by scarce rainfall and strong evaporation in desert mining areas. In addition, the combination of local grass species and stress-resistant mixed grass species results in a significant increase in vegetation coverage after wintering and one year after planting compared to traditional methods.

[0018] 3. Achieve efficient recycling of local resources by transforming cheap sheep manure from the coal mining area into a dual-function material of "fertilizer carrier + grass seed medium". Through a secondary spreading process, the natural mixing of local grass seeds can reach more than 50 seeds / ㎡, which improves the survival rate of vegetation compared with foreign grass seeds. Local sheep manure can replace some of the purchased fertilizers, and snowfall can replace the initial irrigation, thus reducing the overall improvement cost.

[0019] 4. An innovative planting model of "contour furrow + double-layer gradient mulch" is adopted. The furrow structure with a spacing of 0.5m follows the terrain trend. Combined with a 1cm manure-soil mixture layer (for heat preservation and germination promotion) + a 1cm topsoil layer (for wind protection and sand fixation), a "micro-water collection area" is formed, which significantly improves the utilization rate of precipitation and can effectively inhibit the loss of topsoil caused by wind erosion. The improved soil structure and vegetation community are adapted to the desert environment and can naturally form a stable ecosystem without long-term artificial maintenance.

[0020] 5. This invention is easy to operate, and all steps can be achieved by conventional agricultural machinery, making it suitable for large-scale restoration of coal gangue piles (single operation area ≥1000㎡). Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the governance process of the present invention; Figure 2 This is a flowchart illustrating the manufacturing process of the present invention. Figure 3 This is a diagram showing the current state of the waste rock pile before the treatment described in this invention. Figure 4 This is a diagram showing the state of the area after the gravel has been removed. Figure 5 The rock pile after initial loosening and leveling; Figure 6 This is a diagram showing the state of the plant after furrowing according to the present invention; Figure 7This is a diagram showing the state of the grass seeds during sowing; Figure 8 A diagram showing the state of sheep manure mixed with soil after spreading the manure-soil mixture. Figure 9 This is a diagram showing the condition after high-quality soil has been spread. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The core technical solution of this invention is an integrated process of "overwintering pretreatment + compound improvement + ridge-furrow planting", and the specific steps are as follows: (a) Pre-treatment stage (utilizing the synergistic effect of winter snowfall) Timing: Limited to 10-15 days after the onset of winter and before snowfall (usually mid-to-late November in desert areas). At this time, the soil is not frozen, which is convenient for mechanical operations. After snowfall, the soil can be naturally moistened, activating the fertilizer effect of sheep manure. Topsoil loosening and gravel removal: Use a micro-tiller with a power of ≥15kW to loosen the topsoil covering the coal gangue hill to a depth of 0-15cm, and simultaneously screen out gravel with a particle size of ≥3cm (to avoid affecting root growth and the distribution of water-retaining materials). Topsoil leveling: Use a harrow to level the loosened topsoil to prevent water loss after snowfall.

[0025] (II) Composite Improvement Stage (Synergistic Effect of Fertilizer and Water Retention) Basic sheep manure spreading: Spread local sheep manure (sheep manure raised around desert mining areas, fermented and naturally dried until the moisture content is ≤20%) at a rate of 1.5-2.0 kg / m². Sheep manure-soil mixing: Sheep manure is evenly mixed with shallow topsoil by rotary tillage with a micro-tiller (rotary tillage depth 8-10cm) to form a "manure-soil" composite improvement layer, which improves the soil pore structure and slowly releases nutrients; Furrow planning and secondary spreading of sheep manure: According to the preset furrow spacing (fixed at 0.5m), spread localized sheep manure carrying local grass species (dosage 0.8-1.0kg / ㎡, natural mixing of local grass species ≥50 grains / ㎡, including native stress-resistant grass species such as Artemisia argyi and Spiny Sand Fern) along the furrow planning direction of the contour line of the gangue mountain.

[0026] (III) Vegetation Planting Stage (Water Conservation-Sowing-Coverage Synergy) Furrow excavation: Furrows should be excavated along contour lines to avoid soil erosion. Use a furrow opener to excavate furrows along the direction of sheep manure distribution, with the following specifications: spacing 0.5m, furrow width 5-15cm, and furrow depth 15-20cm. Composite water-retaining material spreading: Mix lignocellulose, carboxymethyl cellulose (CMC), and hydroxypropyl methyl cellulose (HPMC) in a mass ratio of 1:1:1 at a rate of 0.3-0.5 kg / m², and spread the water-retaining material evenly on the bottom of the trench (lignocellulose provides physical pores for water retention, CMC and HPMC form a chemical gel to lock in water, and the three work together to improve soil water holding capacity by ≥30%). Sowing of stress-resistant grass seeds: On top of the water-retaining material, evenly sow a mixture of stress-resistant grass seeds (mixture ratio of prickly ash, tall fescue, Suaeda salsa, and ryegrass, sowing rate 15-20g / ㎡). This group is suitable for arid desert and saline-alkali soil environments. First layer of covering: Mix local sheep manure with purchased high-quality topsoil in a 1:1 volume ratio to form a covering material, and evenly cover it on the grass seeds at the bottom of the ditch. The covering thickness should be strictly controlled to 1cm (to keep the grass seeds warm and fertile without burying them, thus ensuring a high germination rate). Second layer of covering: On top of the first layer of covering, spread high-quality topsoil purchased from elsewhere, covering it to a thickness of 1 cm, forming a "ridge planting layer" to prevent water-retaining materials and grass seeds from being blown away by the wind.

[0027] Example 1: Restoration of a coal mine gangue hill on the southern edge of the Junggar Basin 1. Remediation Area: A stable slope on the south side of the coal mine waste disposal site was selected as the remediation area. This area covers approximately 1800㎡ and faces due south. Before remediation, the surface was covered with a 20cm layer of weathered coal gangue debris, resulting in extremely poor initial physical and chemical properties: soil bulk density as high as 1.65 g / cm³. 3 The soil contains 42% gravel with a particle size ≥3cm, only 1 g / kg of organic matter, a pH of 8.7 (alkaline), and a water saturation rate as low as 8%, making it almost unsuitable for vegetation growth.

[0028] 2. Implementation Steps Strictly following the method of this invention, the operation was carried out on November 18 (12 days before local snowfall, local meteorological records show that the first snowfall usually occurs at the end of November).

[0029] Pre-treatment stage: A 18kW mini-tiller is used to loosen the topsoil by rotary tillage to a depth of 15cm. At the same time, a vibrating screen is used to completely remove and remove gravel with a particle size ≥3cm. After treatment, the measured content of large gravel (≥3cm) on the surface is reduced to less than 3%. Then, the surface is leveled with a harrow. After leveling, the local slope is less than 15° to ensure that the surface is flat and there are no local waterlogged depressions.

[0030] Composite improvement stage: Sheep manure preparation: Local sheep manure is used, with 0.2% commercial aerobic fermentation agent added. The compost is fermented for 30 days (maintaining a high temperature of >55℃ for 10 days, turning the pile 3 times during the period). After fermentation, the material is dark brown and odorless, and the seed germination index (GI) reaches 78%. It is then naturally sun-dried (spread 10cm thick and sun-dried for 3 days) until the moisture content is 18%.

[0031] Initial spreading and mixing: Spread the above-mentioned decomposed sheep manure evenly on the ground at a rate of 1.8 kg / m², and then use a micro-tiller to perform rotary tillage to a depth of 10 cm, so that the sheep manure is fully mixed with the top layer (0-10 cm) of weathered gangue soil to form a preliminary improved layer.

[0032] Furrow planning and secondary spreading: Along the contour lines, furrow lines are planned at fixed intervals of 0.5m. Sheep manure that has been naturally mixed with local grass species (Artemisia argyi and Spatholobus suberectus) is spread along the planned lines at a rate of 0.9 kg / m². According to sampling tests, the grass seed density is approximately 55 seeds / m².

[0033] Vegetation planting stage: Use a small trenching machine to dig furrows along the planned lines, with a depth of 15cm and a spacing of 50cm.

[0034] Preparation and application of composite water-retaining material: Lignocellulose powder that has passed through a 60-mesh sieve, carboxymethyl cellulose (CMC, viscosity 1500 mPa·s), and hydroxypropyl methyl cellulose (HPMC, viscosity 1000 mPa·s) are mixed in a dry powder mixer at a mass ratio of 1:1:1 for 15 minutes. The resulting composite water-retaining material is then evenly spread on the bottom of the trench at a dosage of 0.4 kg / m².

[0035] Sowing: On the water-retaining material, artificially sow stress-resistant mixed grass seeds. The ratio of stress-resistant mixed grass seeds is: 30% spiny privet, 25% tall fescue, 25% Suaeda salsa, and 20% ryegrass. The total sowing amount is 18 g / ㎡.

[0036] Double-layer covering: First, use a mulch mixture of fermented sheep manure and purchased high-quality garden soil in a 1:1 volume ratio to evenly cover the grass seeds, with the thickness strictly controlled at 1cm. Then, cover with another layer of pure high-quality garden soil, also 1cm thick, and gently press it down to form the final "ridge and furrow planting layer".

[0037] 3. Effect Verification After restoration, monitoring was conducted after snowfall, in late April of the following year (2023) (seedling stage), in late June (peak growing season), and one year later. After the first snowfall (early December), the soil water holding capacity increased to 32%, the seedling emergence rate was 88% in April of the following year, and the vegetation coverage rate was 75% in June. Through the combination of local grass species and stress-resistant mixed grass species, the seedling emergence rate after overwintering was ≥85%, and the vegetation coverage rate was ≥70% one year after planting, which is more than 40% higher than the traditional method. One year later, the soil organic matter content was 9.5g / kg. After improvement, the soil organic matter content increased from ≤1g / kg to ≥8g / kg, the porosity was ≥25%, the gravel content was ≤5%, the water retention capacity was increased by 3-5 times, and the vegetation survived stably under no irrigation conditions.

[0038] The following comparative examples were set up simultaneously, with each treatment area of ​​500㎡, and repeated 3 times: Comparative Example 1: Blank control, only the surface was leveled, no amendments were applied, and no seeds were sown.

[0039] Comparative Example 2: Traditional fertilizer application method, referring to local common practices, after land preparation, NPK compound fertilizer (N-P2O5-K2O=15-15-15) was applied, which is equivalent to 0.1 kg / m² of pure nitrogen application. No organic fertilizer or water-retaining agent was applied, and the mixed grass seeds of Example 1 were sown.

[0040] Comparative Example 3: Single water-retaining agent mode. After land preparation, a single water-retaining agent, carboxymethyl cellulose (CMC), was applied at a rate of 0.4 kg / m². Sheep manure was not applied, and the mixed grass seed was sown as in Example 1.

[0041] Comparative Example 4: Low sheep manure usage test. Except for the initial sheep manure application rate being reduced to 1.0 kg / m², the other steps were exactly the same as in Example 1.

[0042] Comparative Example 5: High sheep manure usage test. Except for the initial sheep manure application rate being increased to 2.5 kg / m², the other steps were exactly the same as in Example 1.

[0043] Comparative Example 6: Experiment with different water-retaining material ratios. The ratio of composite water-retaining material was changed to lignocellulose:CMC:HPMC = 2:1:1, and the total amount was still 0.4 kg / m². The remaining steps were the same as in Example 1.

[0044] 4. Experimental Data and Results Analysis The monitoring data is summarized in the table below:

[0045]

[0046]

[0047] 5. Comprehensive Analysis and Conclusion Based on the experimental data from the examples and a series of comparative examples, the following conclusions can be drawn: Example 1 showed significantly better performance than traditional single improvement models (Comparative Examples 2 and 3) in all core indicators such as soil water holding capacity, organic matter improvement, vegetation cover and biomass. This fully demonstrates the correctness and efficiency of the technical route of "wintering pretreatment (using snow water) + organic-inorganic composite improvement (sheep manure and water-retaining agent) + ridge and furrow micro-topography". In particular, Comparative Example 3 showed that although the use of chemical water-retaining agent alone can improve water holding capacity, it has little effect on soil fertility (organic matter) and insufficient vegetation growth momentum.

[0048] Table 2 data shows that within this dosage range (sheep manure dosage (1.5-2.0 kg / m²)), the soil organic matter and available nitrogen content reach ideal levels, and the germination rate is also the highest. Below this range (Comparative Example 4), the improvement in fertility is insufficient; above this range (Comparative Example 5), although the indicators are slightly higher, the marginal benefit decreases, and the cost increases, with a potential risk of salt accumulation. Therefore, this range is the optimal choice in terms of cost-effectiveness.

[0049] Table 3 shows that the material ratio of the present invention (composite water-retaining material ratio (1:1:1)) has the highest water absorption ratio, the best improvement in soil water holding capacity and the best rate of water evaporation reduction. This verifies the synergistic effect of lignocellulose (providing physical water storage space) and two cellulose ethers (forming a chemical gel network to lock in water), which is better than any single component or other test ratios (Comparative Example 6).

[0050] Removing gravel ≥3cm: This operation is the basis for the effectiveness of subsequent improvement measures. In the example, the gravel content after treatment is less than 5%, which creates the necessary conditions for the uniform distribution of water-retaining materials, seed contact with soil and root extension. The extremely low vegetation cover of the blank control (Comparative Example 1) directly proves the poor quality of the unimproved substrate.

[0051] This invention constructs a sustainable micro-ecosystem: In Example 1, the plant roots are mainly distributed within the 0-15cm improved layer, coinciding with the furrow depth and the water-retaining material layer, indicating that the plants have effectively utilized the created favorable environment. This virtuous cycle of "soil structure improvement - water and nutrient retention - plant establishment and survival - root system consolidation of the soil" ensures the long-term stability of the restoration effect, eliminating the need for continuous artificial irrigation and maintenance, which aligns with the fundamental goal of ecological restoration in arid areas. The operation is performed before winter snowfall, utilizing the natural infiltration of snow to promote the release of nutrients from sheep manure at low temperatures, while the water-retaining material absorbs snow water, solving the problem of drought... No irrigation or water retention problems in arid areas; a 1:1:1 mixture of lignocellulose (physical water retention) and two types of cellulose ethers (chemical water locking) increases water retention by more than 50% compared to single materials without affecting soil permeability; localized sheep manure serves as both a long-lasting fertilizer and a carrier for local grass seeds, improving the adaptability of vegetation to the local environment; the furrow planting structure uses a 0.5m spacing furrow + double-layer covering design, which reduces surface evaporation and creates micro-topography for water retention, adapting to the windy and evaporative environment of desert areas; removing gravel ≥3cm ensures soil porosity ≥25%, providing space for root growth.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for soil improvement and vegetation reconstruction in coal gangue hills in desert mining areas, characterized in that, Includes the following steps: S1. Pretreatment stage: 10-15 days after the onset of winter and before snowfall, loosen the topsoil covering the coal gangue mountain and remove gravel with a particle size ≥3cm, and then level the topsoil. S2, Composite Improvement Stage: Fermented sheep manure is evenly spread on the pretreated surface and mixed with the shallow topsoil by rotary tillage to form a "manure-soil" composite improvement layer; then, furrow planning is carried out along the preset direction, and the fermented sheep manure carrying local grass seeds is spread along the planned direction. S3. Vegetation planting stage: Dig furrows along the planned direction of the furrows; spread composite water-retaining material evenly at the bottom of the furrows; sow stress-resistant mixed grass seeds on the composite water-retaining material; first, use the first mulch material to evenly cover the grass seeds, and then use the second mulch material to cover them, forming the furrow planting layer; The composite water-retaining material is composed of lignocellulose, carboxymethylcellulose and hydroxypropylmethylcellulose mixed in a mass ratio of 1:1:1; the first covering material is composed of fermented sheep manure and high-quality topsoil mixed in a volume ratio of 1:1; and the second covering material is high-quality topsoil.

2. The method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas according to claim 1, characterized in that, In S1 above, a micro-tiller with a power of ≥15kW is used for loosening operations at a depth of 0-15cm.

3. The method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas according to claim 1, characterized in that, In S2 above, the amount of fermented sheep manure initially spread is 1.5-2.0 kg / m², and the rotary tillage depth is 8-10 cm.

4. The method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas according to claim 1, characterized in that, In S2 above, the preset direction of the furrow planning is along the contour line of the gangue hill, and the furrow spacing is 0.5m.

5. The method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas according to claim 1, characterized in that, In S2 above, the amount of fermented sheep manure carrying local grass seeds spread is 0.8-1.0 kg / m², of which the amount of local grass seeds naturally mixed in is ≥50 grains / m².

6. The method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas according to claim 1, characterized in that, In the above S3, the specifications for the excavated furrows are: furrow width 5-15cm, furrow depth 15-20cm.

7. The method for soil improvement and vegetation reconstruction of coal gangue hills in desert mining areas according to claim 1, characterized in that, In S3 above, the amount of the composite water-retaining material used for spreading is 0.3-0.5 kg / m²; the stress-resistant mixed grass species include Elaeagnus pungens, tall fescue, Suaeda salsa, and ryegrass, with a sowing rate of 15-20 g / m²; the covering thickness of the first mulch material is 1 cm, and the covering thickness of the second mulch material is 1 cm.

8. A method for soil improvement and vegetation reconstruction in coal gangue hills in desert mining areas according to claim 1, characterized in that, The method for preparing fermented sheep manure includes: composting sheep manure for 45-60 days, turning the pile over every 7-10 days during fermentation, and then air-drying it until the moisture content is ≤20% after fermentation.

9. A composite water-retaining material for use in the soil improvement and vegetation reconstruction method for coal gangue hills in desert mining areas as described in any one of claims 1-8, characterized in that, It is made by mixing lignocellulose, carboxymethylcellulose and hydroxypropylmethylcellulose in a mass ratio of 1:1:

1.

10. A ridge-furrow structure for vegetation reconstruction of coal gangue hills constructed using the soil improvement and vegetation reconstruction method for desert mining areas as described in any one of claims 1-8, characterized in that, From the bottom of the ditch upwards, it includes: The composite water-retaining material layer is composed of lignocellulose, carboxymethylcellulose and hydroxypropylmethylcellulose mixed in a mass ratio of 1:1:

1. Grass seed layer; The first covering layer is made of fermented sheep manure and high-quality topsoil mixed in a 1:1 volume ratio, with a covering thickness of 1cm; the second covering layer is made of high-quality topsoil, with a covering thickness of 1cm.

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