Method for repairing open pit coal mine waste dump side slope through water and soil immobilization material

Abstract

The invention belongs to the field of ecological restoration, and provides a method for restoring an open pit coal mine waste dump side slope through a water and soil immobilization material. The method comprises the steps that S1, the side slope is leveled and covered with surface soil; s2, the water and soil immobilization material is combined with plant seeds to plant plants; s3, irrigation; the planting method in the step S2 comprises the steps that after plant seeds are planted on the side slope, water and soil immobilization materials are laid, and the water and soil immobilization materials comprise a straw curtain immobilization material, a plant fiber immobilization material, a gauze straw immobilization material and a reed curtain immobilization material. Or uniformly mixing the plant seeds with the planting soil, the humus, the water-retaining agent, the adhesive and the compound fertilizer to form the plant-growing plate immobilization material, and then paving the plant-growing plate immobilization material on the side slope of the coal mine dump; according to the technical scheme, the problems of water and soil loss and seed loss can be prevented, the water content of the soil surface is increased, the evaporation capacity of the soil surface layer is reduced, the germination rate and the survival rate of the seeds are increased, and the immobilization material is degradable and does not need to be manually cleaned.

Description

Technical Field

[0001] The invention belongs to the field of ecological restoration, and relates to a method for repairing the slope of an open-pit coal mine dump using water and soil holding materials. Background Art

[0002] Over the years, the development, utilization and processing of coal resources have supported the economic and social development of the Inner Mongolia Autonomous Region, but have also led to a series of ecological problems in resource mining areas, such as the fragmentation of grassland landscapes, soil and vegetation degradation, sharp decline in biodiversity, soil erosion, and intensified geological disasters. Therefore, the restoration of mines has become a matter of great concern to people. For the management of the slopes of mine spoil dumps, the existing technology often uses direct sowing of plants on the slopes for restoration. However, since the slopes have an angle of 15-30°, direct sowing often leads to seed loss due to wind erosion or water erosion. Since the seeds are not completely fixed on the slopes, they cannot form seedlings. On the other hand, after direct sowing, since the slopes are all exposed rock and soil, there are problems such as high temperature in summer and inability to retain moisture, which will lead to low germination and survival rates of seeds. Moreover, after direct sowing, before the seedlings form, when the vegetation coverage is low, soil erosion is more serious, so that the seeds cannot be preserved in the soil until they germinate. Even after germination, if they encounter heavy rain, they will be eroded. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a method for repairing the slope of an open-pit coal mine dump using water and soil retaining materials, comprising the following steps: S1. Level the slope and cover the topsoil; S2. Planting plants using soil and water holding materials combined with plant seeds; S3. Irrigation.

[0004] Moreover, in step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after planting plant seeds on the slope, laying water and soil retaining materials, the water and soil retaining materials are straw curtain retaining materials, plant fiber retaining materials, gauze straw retaining materials and reed curtain retaining materials.

[0005] Moreover, in step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after the plant seeds are evenly mixed with planting soil, humus, water retaining agent, adhesive, and compound fertilizer to form water and soil retaining materials, the water and soil retaining materials are laid on the slope of the coal mine spoil dump, and the water and soil retaining materials are planting board retaining materials.

[0006] Moreover, the slope angle of the slope is 15°-30°.

[0007] Moreover, the plants planted in step S2 are native plants of Inner Mongolia with well-developed root systems, strong adaptability, drought resistance, barrenness resistance, and strong resistance to retrograde; the method of planting plant seeds is a combination of strip sowing, hole sowing and aerial sowing.

[0008] Moreover, the native plants of Inner Mongolia are herbs and legumes, and the herbs and legumes are alfalfa, Elymus dahliae, Caragana korshinskii, Artemisia ordosica, Astragalus astragali, and oats.

[0009] Moreover, the planting method of the Inner Mongolia native plants is: Step 1: trim the soil and water retention materials into a grid of fixed size, and position and mark each grid of soil and water retention materials at the laying position of the slope; Step 2: Taking each grid of soil and water retention materials as a unit, dig strips with a width of 35-40 cm and a depth of 20-30 cm at 5-10 cm above and below the positioning ends of the soil and water retention materials, and sow alfalfa and oats in the strips; Step 3: dig a hole with a diameter of 25-35cm and a depth of 15-20cm between the two trenches, and sow Artemisia ordosica and Caragana korshinskii in the hole; Step 4: Use aerial seeding to plant Elymus japonicus and Aspergillus niger.

[0010] Moreover, the laying method of the water and soil retaining material is a flat laying method, in which the water and soil retaining materials are bound together without being stacked, and are fixed on the slope.

[0011] Moreover, the straw curtain holding material is straw curtain, the reed curtain holding material is reed curtain; the plant fiber holding material is cotton fiber and viscose fiber; the gauze straw holding material is a layer of straw laid on the slope and then covered with a layer of gauze.

[0012] Moreover, the proportion of the plant seeds to the growing soil, humus, water retaining agent, adhesive and compound fertilizer is 10-20:350-450:50-100:5-7:8-12:3-5.

[0013] The beneficial effects of the present invention are as follows: 1. The present invention uses straw mats, reed mats, cotton fiber, viscose fiber, straw, and gauze as holding materials, which can be closely combined with the soil surface to prevent and control soil erosion and seed loss, increase the water content of the soil surface and reduce the evaporation of the soil surface, and improve the germination rate and survival rate of seeds; the holding materials are also degradable and do not require manual cleaning.

[0014] 2. The present invention also provides another solution, in which plant seeds are evenly mixed with planting soil, humus, water retaining agent, adhesive and compound fertilizer to form a planting board holding material, which is then laid on the slope of the coal mine spoil dump. Plants grow in the planting board and then take root in the slope soil. This can also prevent and control soil erosion and seed loss, increase the moisture content of the soil surface and reduce the evaporation of the soil surface, improve the germination rate and survival rate of seeds, and the holding material is also degradable, so there is no need for manual cleaning.

[0015] 3. The present invention also provides native plants suitable for the slopes of coal mine dumps in Inner Mongolia, and provides a specific planting method, which is suitable for the management of coal mine dumps in Inner Mongolia. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The effects of different years and fixing materials on vegetation height, coverage, density and biomass on a 15° slope. Figure 2 The effects of different years and fixing materials on vegetation height, coverage, density and biomass on 30° slopes; Figure 3 This is a comparison of vegetation growth between different slopes in 2021; Figure 4 To compare vegetation growth between different slopes in 2022; Figure 5 This is the effect of vegetation greening in 2021. DETAILED DESCRIPTION Example

[0018] A method for repairing the slope of an open-pit coal mine dump using water and soil retaining materials comprises the following steps: S1. Level the slope and cover the topsoil; S2. Planting plants using soil and water holding materials combined with plant seeds; S3. Irrigation.

[0019] Furthermore, in step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after planting plant seeds on the slope, laying water and soil retaining materials, wherein the water and soil retaining materials are straw curtain retaining materials.

[0020] Furthermore, the slope angle of the slope is 15°.

[0021] Furthermore, the plants planted in step S2 are native plants of Inner Mongolia with well-developed root systems, strong adaptability, drought resistance, barrenness resistance, and strong resistance to retrograde; the method of sowing plant seeds adopts a combination of strip sowing, hole sowing and aerial sowing.

[0022] Furthermore, the native plants of Inner Mongolia are herbs and legumes, and the herbs and legumes are alfalfa, Elymus dahliae, Caragana korshinskii, Artemisia ordosica, Astragalus astragali, and oats.

[0023] Furthermore, the planting method of the native plants of Inner Mongolia is: Step 1: trim the soil and water retention materials into a grid of fixed size, and position and mark each grid of soil and water retention materials at the laying position of the slope; Step 2: Taking each grid of soil and water retention materials as a unit, dig strips with a width of 35 cm and a depth of 20 cm at 5 cm above and below the positioning of the soil and water retention materials, and sow alfalfa and oats in the strips; Step 3: dig a hole with a diameter of 25 cm and a depth of 15 cm between the two trenches, and sow Artemisia ordosica and Caragana korshinskii in the hole; Step 4: Use aerial seeding to plant Elymus japonicus and Aspergillus niger.

[0024] Furthermore, the soil and water retaining material is laid in a flat manner, wherein the soil and water retaining materials are bound together without being stacked, and are fixed on the slope.

[0025] Furthermore, the straw curtain holding material is a straw curtain.

[0026] Example 2 A method for repairing the slope of an open-pit coal mine dump using water and soil retaining materials comprises the following steps: S1. Level the slope and cover the topsoil; S2. Planting plants using soil and water holding materials combined with plant seeds; S3. Irrigation.

[0027] Furthermore, in step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after planting plant seeds on the slope, laying water and soil retaining materials, wherein the water and soil retaining materials are plant fiber retaining materials.

[0028] Furthermore, the slope angle of the slope is 30°.

[0029] Furthermore, the plants planted in step S2 are native plants of Inner Mongolia with well-developed root systems, strong adaptability, drought resistance, barrenness resistance, and strong resistance to retrograde; the method of planting plant seeds is a combination of strip sowing, hole sowing and aerial sowing.

[0030] Furthermore, the native plants of Inner Mongolia are herbs and legumes, and the herbs and legumes are alfalfa, Elymus dahliae, Caragana korshinskii, Artemisia ordosica, Astragalus astragali, and oats.

[0031] Furthermore, the planting method of the native plants of Inner Mongolia is: Step 1: trim the soil and water retention materials into a grid of fixed size, and position and mark each grid of soil and water retention materials at the laying position of the slope; Step 2: Taking each grid of soil and water retention materials as a unit, dig strips with a width of 40 cm and a depth of 30 cm at 10 cm above and below the positioning of the soil and water retention materials, and sow alfalfa and oats in the strips; Step 3: dig a hole with a diameter of 35 cm and a depth of 20 cm between the two trenches, and sow Artemisia ordosica and Caragana korshinskii in the hole; Step 4: Use aerial seeding to plant Elymus japonicus and Aspergillus niger.

[0032] Furthermore, the soil and water retaining material is laid in a flat manner, wherein the soil and water retaining materials are bound together without being stacked, and are fixed on the slope.

[0033] Furthermore, the plant fiber holding material is cotton fiber and viscose fiber.

[0034] Example 3 A method for repairing the slope of an open-pit coal mine dump using water and soil retaining materials comprises the following steps: S1. Level the slope and cover the topsoil; S2. Planting plants using soil and water holding materials combined with plant seeds; S3. Irrigation.

[0035] Furthermore, in step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after planting plant seeds on the slope, laying water and soil retaining materials, wherein the water and soil retaining materials are reed curtain retaining materials.

[0036] Furthermore, the slope angle of the slope is 15°.

[0037] Furthermore, the plants planted in step S2 are native plants of Inner Mongolia with well-developed root systems, strong adaptability, drought resistance, barrenness resistance, and strong resistance to retrograde; the method of planting plant seeds is a combination of strip sowing, hole sowing and aerial sowing.

[0038] Furthermore, the native plants of Inner Mongolia are herbs and legumes, and the herbs and legumes are alfalfa, Elymus dahliae, Caragana korshinskii, Artemisia ordosica, Astragalus astragali, and oats.

[0039] Furthermore, the planting method of the native plants of Inner Mongolia is: Step 1: trim the soil and water retention materials into a grid of fixed size, and position and mark each grid of soil and water retention materials at the laying position of the slope; Step 2: Taking each grid of soil and water retention materials as a unit, dig strips with a width of 38 cm and a depth of 25 cm at 8 cm above and below the locations of the soil and water retention materials, and sow alfalfa and oats in the strips; Step 3: dig a hole with a diameter of 30 cm and a depth of 18 cm between the two trenches, and sow Artemisia ordosica and Caragana korshinskii in the hole; Step 4: Use aerial seeding to plant Elymus japonicus and Aspergillus niger.

[0040] Furthermore, the soil and water retaining material is laid in a flat manner, wherein the soil and water retaining materials are bound together without being stacked, and are fixed on the slope.

[0041] Furthermore, the reed curtain holding material is a reed straw curtain.

[0042] Example 4 A method for repairing the slope of an open-pit coal mine dump using water and soil retaining materials comprises the following steps: S1. Level the slope and cover the topsoil; S2. Planting plants using soil and water holding materials combined with plant seeds; S3. Irrigation.

[0043] Furthermore, in step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after the plant seeds are evenly mixed with planting soil, humus, water retaining agent, adhesive, and compound fertilizer to form water and soil retaining materials, the water and soil retaining materials are laid on the slope of the coal mine spoil dump, and the water and soil retaining materials are planting board retaining materials.

[0044] Furthermore, the slope angle of the slope is 30°.

[0045] Furthermore, the plants planted in step S2 are native plants of Inner Mongolia with well-developed root systems, strong adaptability, drought resistance, barrenness resistance, and strong resistance to retrograde; the method of planting plant seeds is a combination of strip sowing, hole sowing and aerial sowing.

[0046] Furthermore, the native plants of Inner Mongolia are herbs and legumes, and the herbs and legumes are alfalfa, Elymus dahliae, Caragana korshinskii, Artemisia ordosica, Astragalus astragali, and oats.

[0047] Furthermore, the planting method of the native plants of Inner Mongolia is: Step 1: trim the soil and water retention materials into a grid of fixed size, and position and mark each grid of soil and water retention materials at the laying position of the slope; Step 2: Taking each grid of soil and water retention materials as a unit, dig strips with a width of 38 cm and a depth of 25 cm at 8 cm above and below the locations of the soil and water retention materials, and sow alfalfa and oats in the strips; Step 3: dig a hole with a diameter of 30 cm and a depth of 18 cm between the two trenches, and sow Artemisia ordosica and Caragana korshinskii in the hole; Step 4: Use aerial seeding to plant Elymus japonicus and Aspergillus niger.

[0048] Furthermore, the soil and water retaining material is laid in a flat manner, wherein the soil and water retaining materials are bound together without being stacked, and are fixed on the slope.

[0049] Furthermore, the ratio of plant seeds to planting soil, humus, water retaining agent, adhesive and compound fertilizer is 15:400:75:6:10:4.

[0050] Experimental Section In June 2021, straw mat retaining materials, plant fiber retaining materials, gauze straw retaining materials, reed mat retaining materials, and vegetation board retaining materials were used on the 15° and 30° coal mine spoil dump slopes, and plants were planted using the technical scheme of the present invention. The test plots were planted, and the CK group served as the control group, and no retaining material treatment was performed.

[0051] Experiment 1 In August 2021 and August 2022, a 1m×1m sample plot was randomly selected in the experimental plot, and the height, density and community cover of the plants in each sample plot were observed. Then each species in the sample plot was mowed evenly, the biomass was bagged and recorded, brought back to the laboratory and dried at 65℃ for 48h, and its weight was weighed and recorded.

[0052] The data were sorted using Excel 2010, plotted using origin10.0, and analyzed using SPSS16.0. The specific results are shown in Table 1.

[0053] Table 1 Three-factor variance analysis of the effects of different years, slopes and fixing materials on the average height, cover, density and biomass of plant communities Note: * represents a significant level at the 0.05 level, and ** represents a significant level at the 0.01 level.

[0054] As can be seen from Table 1, in different years, the average height, coverage, density and biomass of plant communities showed significant differences (P < 0.01); under different slope surfaces, the density of plant communities changed significantly (P < 0.05), while the height, coverage and biomass of plant communities did not change significantly (P > 0.05); under different fixing materials, the average height of plants had significant differences (P < 0.05), and there were no differences in other growth indicators (P > 0.05), because except for the control, the differences in other treatments were not significant, but each treatment was significantly different from the control; the interaction between different years and slope surfaces, and different years and fixing materials had a significant effect on the density of plant communities (P < 0.05).

[0055] Experiment 2 In August 2021 and August 2022, plant samples planted with straw curtains, plant fiber, gauze straw, reed curtains, and vegetation board were collected on the slope of the 15° coal mine dump to observe the growth of vegetation in different years of 2021 and 2022. Figure 1 As shown in the figure, different lowercase letters indicate significant differences among different treatments in the same year, and different uppercase letters indicate significant differences among different years under the same treatment.

[0056] from Figure 1 It can be seen that in 2021, there was no significant difference in vegetation height under different treatments (P>0.05), but the average height of plants in the plots with holding materials (64.07 cm) was higher than that in the CK treatment (54.00 cm). In 2022, the vegetation height under the gauze straw holding material treatment was significantly higher than that in the CK treatment (P<0.05), but the difference in vegetation height under different holding material treatments was not significant (P>0.05), and the average vegetation height in 2021 (62.39 cm) was significantly higher than that in 2022 (40.33 cm) (P<0.05). In the two years, there was no significant difference in vegetation cover among the treatments (P>0.05), but the average vegetation cover in 2021 (69.44%) was significantly higher than that in 2022 (37.28%) (P<0.05). For vegetation density, the density under the plant fiber holding material treatment in 2021 was the highest (440 plants / m 2 ), which was significantly higher than that of CK treatment (210 plants / m 2 ) (P<0.05), but there was no significant difference between the other treatments (P>0.05). In 2022, the vegetation density was also the highest under the plant fiber fixation material (53.67 plants / m 2), which was significantly lower than that in 2021 (P < 0.05). In 2021, the vegetation biomass under the plant fiber fixation material was the largest, but there was no significant difference with other treatments (P > 0.05). In 2022, the difference in vegetation biomass under each treatment was not significant (P > 0.05). During the experiment, we found that the height, density and coverage of vegetation in 2021 were significantly higher than those in 2022. This is because the wind erosion and water erosion of the mine slopes were serious. When we reseeded grass seeds, we chose one- and two-year-old oats and perennial alfalfa, sand dawley, and alkali grass. One- and two-year-old oats are pioneer plants that play a role in fixing the soil. Therefore, oats grew well in 2021, while perennial plants grew slowly, which ultimately led to vegetation coverage and density greater than in 2022.

[0057] Experiment 3 In August 2021 and August 2022, plant samples planted with straw curtains, plant fiber, gauze straw, reed curtains, and vegetation board were collected on the 30° coal mine dump slope to observe the growth of vegetation in different years of 2021 and 2022. Figure 2 As shown in the figure, different lowercase letters indicate significant differences among different treatments in the same year, and different uppercase letters indicate significant differences among different years under the same treatment.

[0058] from Figure 2 It can be seen that in 2021, the vegetation height under the treatment of vegetation board fixing material was the largest (86.67 cm), which was significantly higher than other treatments except gauze straw fixing material (P < 0.05). In 2022, the vegetation height under the treatment of reed curtain fixing material and gauze straw fixing material was significantly higher than that of CK treatment (P < 0.05). For vegetation coverage, it was the highest under the treatment of plant fiber fixing material in 2021 (88.33%), which was significantly higher than that of gauze straw fixing material and CK treatment (P < 0.05), while there was no significant difference in vegetation coverage among the treatments in 2022 (P > 0.05). For vegetation density, the vegetation density under the treatment of plant fiber fixing material was the largest in 2021 (375.67 plants / m 2 ), which was significantly higher than the vegetation density of the treatments with vegetation board, gauze straw and reed curtain (P < 0.05). There was no significant difference among the treatments in 2022 (P > 0.05), but the vegetation density of the treatments with fixed materials was higher than that of the CK treatment, with an average vegetation density of 50.33 plants / m 2 , 15.33 plants / m 2 For vegetation biomass, there was no significant difference among the treatments in 2021 (P>0.05). The vegetation density of the treatment with fixation materials was higher than that of the CK treatment, and the average vegetation biomass was 82.12 g / m 2, 46.00 g / m 2 In 2020, the vegetation biomass under the treatment of reed curtain fixation material was the largest (229 g / m 2 ), significantly higher than the straw mat holding material (106.44 g / m 2 ), plant fiber holding material (90.66 g / m 2 ) and CK treatment (84.20 g / m 2 ) (P < 0.05). In addition, regardless of vegetation height, coverage, density and biomass, 2021 was significantly higher than 2022 (P < 0.05). This is because the mine slopes were severely eroded by wind and water. When we reseeded grass seeds, we chose one- and two-year-old oats and perennial alfalfa, Adansonia sinensis, and alkali grass. One- and two-year-old oats serve as pioneer plants and play a role in fixing the soil. Therefore, oats grew well in 2021, while perennial plants grew slowly, which ultimately led to vegetation coverage and density greater than in 2022.

[0059] Experiment 4 The samples taken in 2021 in Experiment 2 and the samples taken in 2021 in Experiment 3 were selected to observe the growth of vegetation on different slopes in 2021. Figure 3 As shown in the figure, different lowercase letters indicate significant differences among different treatments in the same year, and different uppercase letters indicate significant differences among different years under the same treatment.

[0060] from Figure 3 It can be seen that the vegetation height of the 15° slope under the plant fiber fixation material and CK treatment was significantly higher than that of the 30° slope (P < 0.05), and the average vegetation height of the two slopes was 62.39 cm and 59.33 cm, respectively. There was no significant difference in vegetation coverage between the two slopes (P > 0.05), while the vegetation density of the 15° slope under the CK treatment was significantly higher than that of the 30° slope, with an average vegetation coverage and density of 69.44% and 314.67 plants / m, respectively. 2 and 70.56%, 215.44 plants / m 2 For plant biomass, the 15° slope was significantly higher than that of the 30° slope under the straw mat fixation material, plant fiber fixation material and CK treatments (P < 0.05).

[0061] Experiment 5 Select the samples taken in 2022 in Experiment 2 and the samples taken in 2022 in Experiment 3 to observe the growth of vegetation on different slopes in 2023. Figure 4 As shown in the figure, different capital letters indicate significant differences among different years under the same treatment.

[0062] from Figure 4It can be seen that there is a significant difference in vegetation height between the two slopes under the reed curtain fixation material and CK treatment (P < 0.05). The average vegetation height of the 15° and 30° slopes is 34.33 cm and 38.11 cm, respectively. There is no significant difference in vegetation coverage and density between the two slopes under different fixation material treatments except for CK treatment (P > 0.05), and the average vegetation coverage and density are 38.28% and 48.89 plants / m, respectively. 2 and 41.06%, 53.50 plants / m 2 For plant biomass, there was no significant difference between the two slopes under all treatments (P>0.05).

[0063] From the above experiments, it can be seen that in 2021 and 2022, the plants planted with soil and water retention materials on the 15° and 30° slopes had higher plant density, height, coverage, and biomass than the CK group. It can be seen that the plants planted with the soil and water retention materials of the present invention grew well, and the effect was more significant than that of the CK group, proving that the technical solution of the present invention has better effect.

Claims

1. A method for repairing the slope of an open-pit coal mine dump using water and soil holding materials, characterized in that: The steps include: S1. Level the slope and cover the topsoil; S2. Planting plants using soil and water holding materials combined with plant seeds; S3. Irrigation.

2. A method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 1, characterized in that: In step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after planting plant seeds on the slope, laying water and soil retaining materials, the water and soil retaining materials are straw curtain retaining materials, plant fiber retaining materials, gauze straw retaining materials and reed curtain retaining materials.

3. The method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 1, characterized in that: In step S2, the specific method of planting plants by combining water and soil retaining materials with plant seeds is: after the plant seeds are evenly mixed with planting soil, humus, water retaining agent, adhesive, and compound fertilizer to form water and soil retaining materials, the water and soil retaining materials are laid on the slope of the coal mine spoil dump, and the water and soil retaining materials are planting board retaining materials.

4. The method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 1, characterized in that: The slope angle of the side slope is 15°-30°.

5. The method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 2, characterized in that: The plants planted in step S2 are native plants of Inner Mongolia with well-developed root systems, strong adaptability, drought resistance, barrenness resistance, and strong resistance to retrograde; the method of planting plant seeds is a combination of strip sowing, hole sowing and aerial sowing.

6. A method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 5, characterized in that: The native plants of Inner Mongolia are herbs and legumes, and the herbs and legumes are alfalfa, Elymus dahliae, Caragana korshinskii, Artemisia ordosica, Astragalus astragali, and oats.

7. A method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 6, characterized in that: The planting method of the Inner Mongolia native plants is: Step 1: trim the soil and water retention materials into a grid of fixed size, and position and mark each grid of soil and water retention materials at the laying position of the slope; Step 2: Taking each grid of soil and water retention materials as a unit, dig strips with a width of 35-40 cm and a depth of 20-30 cm at 5-10 cm above and below the positioning ends of the soil and water retention materials, and sow alfalfa and oats in the strips; Step 3: dig a hole with a diameter of 25-35cm and a depth of 15-20cm between the two trenches, and sow Artemisia ordosica and Caragana korshinskii in the hole; Step 4: Use aerial seeding to plant Elymus japonicus and Aspergillus niger.

8. The method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 1, characterized in that: The laying method of the water and soil retaining material is a flat laying method, in which the water and soil retaining materials are bound together without being stacked, and are fixed on the slope.

9. The method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 1, characterized in that: The straw curtain holding material is a straw curtain, the reed curtain holding material is a reed curtain; the plant fiber holding material is cotton fiber and viscose fiber; the gauze straw holding material is a layer of straw laid on the slope and then covered with a layer of gauze.

10. The method for repairing the slope of an open-pit coal mine dump using water and soil holding materials as claimed in claim 3, characterized in that: The proportion of the plant seeds to the growing soil, humus, water retaining agent, adhesive and compound fertilizer is 10-20: 350-450: 50-100: 5-7: 8-12: 3-5.

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