Vegetation recovery method for strip mine in grassland area

Abstract

The invention discloses a grassland area strip mine vegetation recovery method, and relates to the technical field of mining area vegetation recovery, and the method comprises the following steps: clearing and leveling a recovered land parcel: removing sundries, dead wood and weeds on the land parcel, and digging out broken stones on the earth surface and large stones buried in soil for clearing; according to the method, grass such as wheatgrass, elymus dahuricus, sweet clover and puccinellia angulata and shrubs such as cornus swida, Gansu berberis thunbergii, buxus sinica and alhagi sparsifolia are planted in a mixed mode, the grass or the shrubs are developed in root system, high in vitality and extremely high in adaptability to the environment, soil is gradually compacted under the action of vegetation root systems and is not prone to loss, meanwhile, vegetation is spread all over the ground, and the soil is not prone to damage. The land surface environment is improved, the probability of sand storm occurrence is reduced, grassland pasture gradually recovers along with continuous growth of vegetation, the quality and yield of grassland pasture gradually increase, and the biodiversity of plant communities gradually recovers, so that the service function of a grassland ecosystem gradually recovers, and the grassland ecosystem can work normally.

Description

Technical Field

[0001] The invention relates to the technical field of vegetation restoration in mining areas, and in particular to a method for restoring vegetation in open-pit mines in grassland areas. Background Art

[0002] Mineral resources are the product of the long-term formation, development and evolution of the earth's crust. They are formed by the aggregation of minerals in nature under certain geological conditions and through certain geological actions. Different geological actions can form different types of minerals. According to the geological actions and energy and material sources that form mineral resources, the geological actions that form mineral resources, namely mineralization, are generally divided into endogenous mineralization, exogenous mineralization, metamorphic mineralization and superimposed mineralization. Energy minerals are an important part of my country's mineral resources. Coal, oil and natural gas account for about 93% and 95% of the world's and China's primary energy consumption respectively. Since mineral energy occupies a dominant position in primary energy consumption, it has a particularly important strategic significance for the national economy and social development. Whether minerals can be formed, how much they are formed and their quality are directly related to the quality of the mineralization geological conditions in the region. Mining plays an important role in China's national economy. With the development of my country's economy and the continuous increase in demand for mineral resources, the development and utilization of coal resources have caused a series of ecological and environmental problems. If the vegetation cover of the developed mining area is not restored, some adverse effects may occur in the future. Therefore, revegetation and ecological restoration of open-pit coal mine spoil dumps is a difficult problem that needs to be solved urgently. Summary of the invention

[0003] The purpose of this application is to provide a method for vegetation restoration in open-pit mines in grassland areas to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above purpose, the present application provides the following technical solution: a method for vegetation restoration in open-pit mines in grassland areas, comprising the following steps:

[0005] S1: Cleaning and leveling of the restoration plot: remove the debris, dead trees and weeds on the plot, dig out the gravel on the surface and the large stones buried in the soil for cleaning, level the protruding parts of the plot, fill the earth pits on the plot, and use the soil dug out when leveling the protruding plots. When leveling the plot, use the soil of the protruding plots and the pits to complement each other, and use the soil in the plot as much as possible for leveling to avoid earthwork transfer;

[0006] S2: Improvement of soil environment of restored plots: After the plots are cleared and leveled, the vegetation to be planted for vegetation restoration is determined, and the soil is improved according to the soil environment required for vegetation planting. During the improvement, soil samples are taken from different locations of the plots, and the acidity and alkalinity of the soil are tested. After the test is completed, the acidity and alkalinity of the soil are adjusted. When adjusting the acidity and alkalinity, the restored plots are first rotary tilled. While rotary tilling, the substances used to adjust the acidity and alkalinity of the soil are sprinkled on the plots. As the machine continues to rotary till, the regulating substances are fully mixed with the soil to complete the improvement of the soil environment;

[0007] S3: Supplementing the fertility of the soil in the restored plot: After adjusting the soil acidity and alkalinity, wait for 5 to 7 days to allow the regulating substance to fully combine with the soil, then take samples again to test the soil acidity and alkalinity. After the test is completed, if the soil pH value meets the requirements, proceed to the next step. If the soil pH value does not meet the requirements, continue to wait until the soil pH value meets the requirements. After the soil environment meets the requirements, use organic fertilizer to supplement the soil in the restored plot. When supplementing fertilizer, spread the organic fertilizer in multiple times, and rotary till the soil after each spreading until all the organic fertilizer is spread;

[0008] S4: Planting: When planting, make horizontal and vertical grooves with equal distances on the plot, evenly spread the prepared grass seeds in the horizontal and vertical grooves, and evenly spread the shrub seeds in the square plots formed by the horizontal and vertical grooves. After the seeds are planted, cover the planting plots with soil to cover the grass and shrub seeds. When planting, try to choose before the rainy season. If planting is carried out outside the rainy season, the planting plots need to be irrigated manually after the planting is completed. During artificial irrigation, the irrigation amount needs to completely wet the soil of the planting plots.

[0009] S5: Vegetation maintenance in planting plots: After the vegetation is planted, if it is planted in the non-rainy season, artificial irrigation and watering are required every 2 to 3 days. After the vegetation germinates, it is top-dressed. The topdressing is mainly spraying nutrient solution. When topdressing, it is done every 7 to 10 days. At the same time, insect repellent is sprayed regularly to prevent and control diseases and pests of the vegetation. After the vegetation is fully grown and formed, the vegetation can be top-dressed once every six months.

[0010] Preferably, the soil pH value of the restoration plot is between 6 and 7. When adjusting the soil pH value, if the soil is acidic, wood ash is added to the soil to increase the soil pH value; if the soil is alkaline, sulfur or aluminum sulfate is added to the soil to reduce the soil pH value.

[0011] Preferably, when the planting soil is acidic, the amount of wood ash to be applied is 200-300 kg per mu. If sulfur is applied when the planting soil is alkaline, the amount of sulfur applied is 30-50 kg per mu. If aluminum sulfate is applied, the amount of aluminum sulfate applied is 20-30 kg per mu.

[0012] Preferably, when the soil acidity and alkalinity are tested before and after the soil improvement, the sampling position and the number of samples should be the same. When sampling, the number of samples shall not be less than eight groups. When the soil acidity and alkalinity are tested after the soil improvement, sampling should be carried out every day for 4 to 6 days. The results shall be recorded after each sampling test, and the results of each sampling test shall be compared until the pH value data no longer changes.

[0013] Preferably, the raw materials of the organic fertilizer used to supplement the fertility of the soil in the restored plot include livestock manure, straw, soybean meal, and rice husks, and the raw material ratio of the organic fertilizer is 80-100 parts of livestock manure, 70-80 parts of straw, 30-50 parts of soybean meal, and 30-40 parts of rice husks.

[0014] Preferably, the fermentation time of the organic fertilizer raw material is 20 to 25 days, the livestock manure in the organic fertilizer raw material needs to be matured chicken manure, duck manure or goose manure, and the amount of the organic fertilizer is 400 to 500 kilograms per mu of land.

[0015] Preferably, when the vegetation is top-dressed, the raw materials of the nutrient solution for topdressing include ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate. The nutrient solution is prepared by mixing ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate with water in a certain proportion.

[0016] Preferably, the specific ratio of ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder and manganese sulfate in the topdressing fertilizer is 15-20 grams of ammonium sulfate, 50-60 grams of superphosphate, 30-50 grams of magnesium sulfate, 30-35 grams of potassium sulfate, 5-10 grams of boric acid powder and 5-10 grams of manganese sulfate, and the above ratio is the configuration amount per 200 liters of water.

[0017] Preferably, when topdressing the vegetation in the restored plot, the amount of fertilizer used is 100 to 150 liters per mu of land, and when improving the soil environment of the restored plot, the soil is tilled to a depth of 30 to 40 centimeters. The soil needs to be tilled repeatedly, and the number of soil tillages is 8 to 10 times.

[0018] Preferably, the grass species planted when the restoration plot is restored are one or more of ice grass, Elymus ovata, Melilotifolia, Puccinellia sphaerocephala, Leymus chinensis, Leymus chinensis, and Stipa krylovii, and the types of shrubs are one or more of Alpinia sphaerocephala, Ceratoides arborescens, Caragana grandis, Berberis dasyphylla, Boxwood, and Camel thorn.

[0019] In summary, the technical effects and advantages of the present invention are as follows:

[0020] In the present invention, the soil environment of the plot to be restored is improved by a series of operations such as cleaning and leveling, improving the soil environment, and supplementing fertility in sequence, so as to make it more suitable for vegetation planting, and then through operations such as vegetation sowing and vegetation maintenance, suitable windbreak and sand-fixing grasses such as ice grass, alkali grass, sweet clover, alkali grass, Leymus, sheep fescue, and Stipa krylovii and easy-to-grow shrubs such as sandwort, camel hairtail, red-flowered caragana, Berberis gansuensis, boxwood, and camel thorn are mixed and planted. The above-mentioned grasses or shrubs have developed root systems, strong vitality, and have strong adaptability to the environment. With the growth of the above-mentioned vegetation, the soil is gradually compacted under the action of the vegetation roots and is not easy to lose. At the same time, the ground is covered with vegetation, which improves the surface environment and reduces the probability of sandstorms. With the continuous growth of vegetation, grassland forage gradually recovers, its quality and yield gradually increase, and the biodiversity of plant communities gradually recovers, so that the grassland ecosystem service function gradually recovers and can work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of the operational process of a method for restoring vegetation in open-pit mines in grassland areas proposed in this application. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1: Reference Figure 1 A method for restoring vegetation in an open-pit mine in a grassland area is shown, comprising the following steps:

[0025] S1: Cleaning and leveling of the restoration plot: remove the debris, dead trees and weeds on the plot, dig out the gravel on the surface and the large stones buried in the soil for cleaning, level the protruding parts of the plot, fill the earth pits on the plot, and use the soil dug out when leveling the protruding plots. When leveling the plot, use the soil of the protruding plots and the pits to complement each other, and use the soil in the plot as much as possible for leveling to avoid earthwork transfer;

[0026] S2: Improvement of soil environment of restored plots: After the plots are cleared and leveled, the vegetation to be planted for vegetation restoration is determined, and the soil is improved according to the soil environment required for vegetation planting. During the improvement, soil samples are taken from different locations of the plots, and the acidity and alkalinity of the soil are tested. After the test is completed, the acidity and alkalinity of the soil are adjusted. When adjusting the acidity and alkalinity, the restored plots are first rotary tilled. While rotary tilling, the substances used to adjust the acidity and alkalinity of the soil are sprinkled on the plots. As the machine continues to rotary till, the regulating substances are fully mixed with the soil to complete the improvement of the soil environment;

[0027] S3: Supplementing the fertility of the soil in the restored plot: After adjusting the soil acidity and alkalinity, wait for 5 to 7 days to allow the regulating substance to fully combine with the soil, then take samples again to test the soil acidity and alkalinity. After the test is completed, if the soil pH value meets the requirements, proceed to the next step. If the soil pH value does not meet the requirements, continue to wait until the soil pH value meets the requirements. After the soil environment meets the requirements, use organic fertilizer to supplement the soil in the restored plot. When supplementing fertilizer, spread the organic fertilizer in multiple times, and rotary till the soil after each spreading until all the organic fertilizer is spread;

[0028] S4: Planting: When planting, make horizontal and vertical grooves with equal distances on the plot, evenly spread the prepared grass seeds in the horizontal and vertical grooves, and evenly spread the shrub seeds in the square plots formed by the horizontal and vertical grooves. After the seeds are planted, cover the planting plots with soil to cover the grass and shrub seeds. When planting, try to choose before the rainy season. If planting is carried out outside the rainy season, the planting plots need to be irrigated manually after the planting is completed. During artificial irrigation, the irrigation amount needs to completely wet the soil of the planting plots.

[0029] S5: Vegetation maintenance in planting plots: After the vegetation is planted, if it is planted in the non-rainy season, artificial irrigation and watering are required every 2 to 3 days. After the vegetation germinates, it is top-dressed. The topdressing is mainly spraying nutrient solution. When topdressing, it is done every 7 to 10 days. At the same time, insect repellent is sprayed regularly to prevent and control diseases and pests of the vegetation. After the vegetation is fully grown and formed, the vegetation can be top-dressed once every six months.

[0030] As a preferred implementation mode of this embodiment, the soil pH value of the restoration plot is between 6 and 7. When adjusting the soil pH value, if the soil is acidic, the soil pH value is increased by applying wood ash to the soil. If the soil is alkaline, the soil pH value is reduced by applying sulfur or aluminum sulfate to the soil.

[0031] As a preferred implementation manner of this embodiment, when the planting soil is acidic, the amount of wood ash to be applied is 200 to 300 kilograms per mu. If sulfur is applied when the planting soil is alkaline, the amount of sulfur applied is 30 to 50 kilograms per mu. If aluminum sulfate is applied, the amount of aluminum sulfate applied is 20 to 30 kilograms per mu.

[0032] As a preferred implementation mode of this embodiment, when the soil acidity and alkalinity are tested before and after the soil improvement, the sampling position and the number of samples should be the same. When sampling, the number of samples shall not be less than eight groups. When the soil acidity and alkalinity are tested after the soil improvement, sampling should be carried out every day. The sampling lasts for 4 to 6 days. The results are recorded after each sampling test, and the results of each sampling test are compared until the pH value data no longer changes.

[0033] As a preferred implementation manner of this embodiment, the raw materials of the organic fertilizer used to supplement the fertility of the soil in the restored plot include livestock manure, straw, soybean meal, and rice husks. The raw material ratio of the organic fertilizer is 80 to 100 parts of livestock manure, 70 to 80 parts of straw, 30 to 50 parts of soybean meal, and 30 to 40 parts of rice husks.

[0034] As a preferred implementation manner of this embodiment, the fermentation time of the organic fertilizer raw material is 20 to 25 days, the livestock manure in the organic fertilizer raw material needs to be selected from mature chicken manure, duck manure or goose manure, and the amount of the organic fertilizer is 400 to 500 kilograms per mu of land.

[0035] As a preferred implementation manner of this embodiment, when the vegetation is topdressed, the raw materials of the nutrient solution for topdressing include ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate. The nutrient solution is prepared by mixing ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate with water in a certain proportion.

[0036] As a preferred implementation manner of this embodiment, the specific ratio of ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate in the topdressing fertilizer is 15-20 grams of ammonium sulfate, 50-60 grams of superphosphate, 30-50 grams of magnesium sulfate, 30-35 grams of potassium sulfate, 5-10 grams of boric acid powder, and 5-10 grams of manganese sulfate. The above ratio is the configuration amount per 200 liters of water.

[0037] As a preferred implementation mode of this embodiment, when the vegetation of the restored plot is topdressed, the amount of fertilizer used is 100 to 150 liters per mu of land. When the soil environment of the restored plot is improved, the soil is tilled to a depth of 30 to 40 centimeters. The soil needs to be tilled repeatedly, and the number of soil tillages is 8 to 10 times.

[0038] As a preferred implementation manner of this embodiment, the grass species planted when the restoration plot is restored are one or more of ice grass, Elymus ovata, Melilotus strychnifolia, Puccinellia sphaerocephala, Leymus chinensis, Leymus chinensis, and Stipa krylovii, and the types of shrubs are one or more of Alpinia sphaerocephala, Ceratoides arborvitae, Caragana grandiflora, Berberis chinensis, Boxwood, and Camel thorn.

[0039] Table 1: Changes of soil pH over time during pH regulation

[0040]

[0041] Table 2: Comparison of germination and growth time of plants in fertilized soil and unfertilized soil (taking Leymus chinensis as an example)

[0042] Germination time Growing time Topdressing the soil 2 days 5 days Unfertilized soil 4 days 15 days

[0043] Table 3: Comparison of mature height of plants of the same species with and without nutrient solution

[0044] Unit / cm Elymus dahliae Puccinellia tenuifolia Leymus chinensis Sand ash Boxwood Camel thorn Ceratoides arborescens Apply nutrient solution 130 120 90 360 200 45 220 No nutrient solution 80 60 70 180 100 20 80

[0045] Working principle of the present invention:

[0046] In the present invention, the soil environment of the plot to be restored is improved by a series of operations such as cleaning and leveling, improving the soil environment, and supplementing fertility in sequence, so as to make it more suitable for vegetation planting, and then through operations such as vegetation sowing and vegetation maintenance, suitable windbreak and sand-fixing grasses such as ice grass, alkali grass, sweet clover, alkali grass, Leymus, sheep fescue, and Stipa krylovii and easy-to-grow shrubs such as sandwort, camel hairtail, red-flowered caragana, Berberis gansuensis, boxwood, and camel thorn are mixed and planted. The above-mentioned grasses or shrubs have developed root systems, strong vitality, and have strong adaptability to the environment. With the growth of the above-mentioned vegetation, the soil is gradually compacted under the action of the vegetation roots and is not easy to lose. At the same time, the ground is covered with vegetation, which improves the surface environment and reduces the probability of sandstorms. With the continuous growth of vegetation, grassland forage gradually recovers, its quality and yield gradually increase, and the biodiversity of plant communities gradually recovers, so that the grassland ecosystem service function gradually recovers and can work normally.

[0047] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for restoring vegetation in open-pit mines in grassland areas, characterized in that: The following steps are involved: S1: Cleaning and leveling of the restoration plot: remove the debris, dead trees and weeds on the plot, dig out the gravel on the surface and the large stones buried in the soil for cleaning, level the protruding parts of the plot, fill the earth pits on the plot, and use the soil dug out when leveling the protruding plots. When leveling the plot, use the soil of the protruding plots and the pits to complement each other, and use the soil in the plot as much as possible for leveling to avoid earthwork transfer; S2: Improvement of soil environment of restored plots: After the plots are cleared and leveled, the vegetation to be planted for vegetation restoration is determined, and the soil is improved according to the soil environment required for vegetation planting. During the improvement, soil samples are taken from different locations of the plots, and the acidity and alkalinity of the soil are tested. After the test is completed, the acidity and alkalinity of the soil are adjusted. When adjusting the acidity and alkalinity, the restored plots are first rotary tilled. While rotary tilling, the substances used to adjust the acidity and alkalinity of the soil are sprinkled on the plots. As the machine continues to rotary till, the regulating substances are fully mixed with the soil to complete the improvement of the soil environment; S3: Supplementing the fertility of the soil in the restored plot: After adjusting the soil acidity and alkalinity, wait for 5 to 7 days to allow the regulating substance to fully combine with the soil, then take samples again to test the soil acidity and alkalinity. After the test is completed, if the soil pH value meets the requirements, proceed to the next step. If the soil pH value does not meet the requirements, continue to wait until the soil pH value meets the requirements. After the soil environment meets the requirements, use organic fertilizer to supplement the soil in the restored plot. When supplementing fertilizer, spread the organic fertilizer in multiple times, and rotary till the soil after each spreading until all the organic fertilizer is spread; S4: Planting: When planting, make horizontal and vertical grooves with equal distances on the plot, evenly spread the prepared grass seeds in the horizontal and vertical grooves, and evenly spread the shrub seeds in the square plots formed by the horizontal and vertical grooves. After the seeds are planted, cover the planting plots with soil to cover the grass and shrub seeds. When planting, try to choose before the rainy season. If planting is carried out outside the rainy season, the planting plots need to be irrigated manually after the planting is completed. During artificial irrigation, the irrigation amount needs to completely wet the soil of the planting plots. S5: Vegetation maintenance in planting plots: After the vegetation is planted, if it is planted in the non-rainy season, artificial irrigation and watering are required every 2 to 3 days. After the vegetation germinates, it is top-dressed. The topdressing is mainly spraying nutrient solution. When topdressing, it is done every 7 to 10 days. At the same time, insect repellent is sprayed regularly to prevent and control diseases and pests of the vegetation. After the vegetation is fully grown and formed, the vegetation can be top-dressed once every six months.

2. The method for vegetation restoration in open-pit mines in grassland areas according to claim 1, characterized in that: The soil pH value of the restoration plot is between 6 and 7. When adjusting the soil pH value, if the soil is acidic, wood ash is added to the soil to increase the soil pH value. If the soil is alkaline, sulfur or aluminum sulfate is added to the soil to reduce the soil pH value.

3. The method for restoring vegetation in open-pit mines in grassland areas according to claim 2, characterized in that: When the planting soil is acidic, the amount of wood ash required to be applied is 200-300 kg per mu. If sulfur is applied, the amount of sulfur applied is 30-50 kg per mu. If aluminum sulfate is applied, the amount of aluminum sulfate applied is 20-30 kg per mu.

4. The method for restoring vegetation in open-pit mines in grassland areas according to claim 1, characterized in that: When conducting soil acidity and alkalinity testing before and after soil improvement, the sampling location and sampling quantity should be the same. When sampling, the sampling quantity shall not be less than eight groups. When conducting soil acidity and alkalinity testing after soil improvement, sampling should be carried out daily for 4 to 6 days. The results shall be recorded after each sampling test, and the results of each sampling test shall be compared until the pH value data no longer changes.

5. The method for restoring vegetation in open-pit mines in grassland areas according to claim 2, characterized in that: The raw materials of the organic fertilizer used to supplement the fertility of the soil in the restored plot include livestock manure, straw, soybean meal, and rice husk. The raw material ratio of the organic fertilizer is 80-100 parts of livestock manure, 70-80 parts of straw, 30-50 parts of soybean meal, and 30-40 parts of rice husk.

6. The method for restoring vegetation in open-pit mines in grassland areas according to claim 5, characterized in that: The fermentation time of the organic fertilizer raw material is 20 to 25 days. The livestock manure in the organic fertilizer raw material needs to be mature chicken manure, duck manure or goose manure. The amount of the organic fertilizer is 400 to 500 kilograms per mu of land.

7. The method for restoring vegetation in open-pit mines in grassland areas according to claim 1, characterized in that: When the vegetation is top-dressed, the raw materials of the nutrient solution for topdressing include ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate. The nutrient solution is prepared by mixing ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder, and manganese sulfate with water in a certain proportion.

8. The method for restoring vegetation in open-pit mines in grassland areas according to claim 7, characterized in that: The specific ratio of ammonium sulfate, superphosphate, magnesium sulfate, potassium sulfate, boric acid powder and manganese sulfate in the nutrient solution for topdressing is 15-20 grams of ammonium sulfate, 50-60 grams of superphosphate, 30-50 grams of magnesium sulfate, 30-35 grams of potassium sulfate, 5-10 grams of boric acid powder and 5-10 grams of manganese sulfate. The above ratio is the configuration amount per 200 liters of water.

9. The method for restoring vegetation in open-pit mines in grassland areas according to claim 8, characterized in that: When topdressing the vegetation in the restored plot, the amount of fertilizer used is 100-150 liters per mu of land. When improving the soil environment of the restored plot, the soil is tilled to a depth of 30-40 centimeters. The soil needs to be tilled repeatedly, and the number of soil tillages is 8-10 times.

10. The method for restoring vegetation in open-pit mines in grassland areas according to claim 1, characterized in that: The grass species planted when the restoration plot is restored are one or more of ice grass, Elymus dahliae, Melilotus officinalis, Puccinellia tenuifolia, Leymus chinensis, Leymus chinensis, and Stipa krylovii, and the types of shrubs are one or more of Alpinia serrata, Ceratoides arborescens, Caragana grandis, Berberis dasyphylla, Boxwood, and Camel thorn.

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