Method suitable for soil improvement of waste dump in high and cold grassland mining area

Abstract

The invention provides a method suitable for soil improvement of a waste dump in a high and cold grassland mining area, and belongs to the technical field of ecological environment soil improvement. The method suitable for soil improvement of the waste dump in the high and cold grassland mining area comprises the following steps that 1, an ecological four-dimensional fertilizer is selected as a base fertilizer, fertilization is conducted in the middle ten days of May, and then rotary tillage and irrigation are conducted; 2, after irrigation is completed, soil preparation is carried out, ecological bags are sown, and then irrigation is carried out; 3, when the plants grow to the tillering stage, two-dimensional fertilizer is applied for topdressing, and irrigation is conducted immediately after the two-dimensional fertilizer is applied; topdressing is conducted when the plants grow to the initial flowering stage in the next year; topdressing is carried out for 3 years. According to the method, a series of technical means such as application of the ecological four-dimensional pesticide fertilizer, planting of the ecological bags, topdressing and maintenance are adopted, and the purposes of improving the physicochemical properties of the soil of the waste dump in the high and cold grassland mining area and improving the plant habitat condition are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of ecological environment soil improvement, and in particular to a method for improving soil in a mine dump in an alpine grassland. Background Art

[0002] Grassland areas are rich in coal resources. For example, the grassland area in Inner Mongolia has become the frontier of coal resource development. Coal resource mining causes ecological problems such as grassland degradation, groundwater level decline, and biodiversity reduction. Especially open-pit mining operations, after long-term ecological accumulation effects and spatial expansion, have a serious negative impact on the ecology of mining areas and surrounding areas, leading to grassland ecological deterioration and seriously affecting the normal functioning of grassland ecosystem service functions. The alpine grassland area has the characteristics of low annual average temperature, long and cold winter, and strong wind and sand, which makes the natural ecological environment extremely fragile. Therefore, the improvement of the soil in the spoil dump of the alpine grassland mining area is extremely important for improving the ecological environment of the mining area, rebuilding vegetation, and affecting the surrounding environment. In the ecological restoration of the mining area, under the premise that soil erosion is effectively controlled, the primary factor for restoring or rebuilding vegetation is soil conditions. Only when the soil habitat has plant growth conditions will the entire ecosystem develop in the direction of a virtuous cycle. Therefore, a reasonable soil improvement plan combined with suitable pioneer plants is a breakthrough in the current technical bottleneck of vegetation restoration in the spoil dump of the alpine grassland mining area.

[0003] In recent years, pilot projects and scientific research related to ecological governance have been carried out in the ecological governance of mining areas in the northern alpine grasslands. The implementation of these projects has greatly promoted the improvement of the ecological environment of the grasslands in the mining areas and the improvement of the quality of life of the people in the mining areas, and the vegetation and biodiversity have also been restored. However, there are still many problems in the ecological restoration and vegetation restoration of open-pit coal mine dumps in the northern alpine grassland mining areas. For example, plant varieties that perform well in most parts of the country, can safely survive the winter, and have excellent production performance cannot survive the severe winter in extremely cold areas such as Hulunbuir. For example, the monitoring and research results of the Yimin open-pit coal mine dump management test site in the Ewenki Autonomous Banner of Hulunbuir City showed that either they were frozen to death in winter or died in large numbers during the late spring cold. In the first year, more than 20 kinds of plants were planted in the ecological restoration of the dump. After the greening monitoring in the second year, only 5 to 6 kinds of varieties could be greened, and only 2 to 3 kinds were left in the third year, forming a large area of ​​bald spots or weeds instead. In particular, the dumping areas with poor soil conditions such as sandstone, alkaline soil, coal gangue, gravel, etc., where waste stripping soil from mines accumulates, need to be reseeded every year. In addition, due to the high cost of covering the planting area with soil, the scarcity of soil sources, and the insufficient thickness of the planting soil layer, the soil habitat develops slowly. Therefore, in addition to selecting excellent plant varieties and plant configuration combinations that are cold-resistant, drought-resistant, and salt-tolerant in the climate conditions of the alpine grassland, more attention should be paid to in-depth research on measures to improve the soil habitat of the dumping areas where stripping soil from open-pit coal mines accumulates, and using technical measures such as soil bioengineering to enhance the ecological restoration function and effect of the mining area. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for improving the soil in the spoil dump of alpine grassland mining areas. The present invention utilizes the strengthening effect of soil structure during plant growth and the comprehensive effect of ecological four-dimensional fertilizers to improve the structure and material and energy conversion functions of the spoil dump soil ecosystem, and enhance the vegetation restoration effect and ecological restoration effect in the mining area.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for improving soil in a mine dump in an alpine grassland comprises the following steps:

[0007] Step 1, select ecological four-dimensional fertilizer as base fertilizer, apply fertilizer in mid-May, and then perform rotary tillage and irrigation;

[0008] Step 2: After irrigation, prepare the land, spread the eco-bags, and then irrigate;

[0009] Step 3, when the plants grow to the tillering stage, apply two-dimensional fertilizer as topdressing, and irrigate immediately after applying; the next year, when the plants grow to the initial flowering stage, apply topdressing; the topdressing lasts for 3 years in total;

[0010] The ecological four-dimensional fertilizer is composed of organic fertilizer, inorganic fertilizer, microbial fertilizer and microecological fertilizer, wherein, by mass percentage, the mass ratios of organic fertilizer, inorganic fertilizer, microbial fertilizer and microecological fertilizer to the ecological four-dimensional fertilizer are 50%, 20%, 20% and 10% respectively;

[0011] The eco-bag is composed of ryegrass seeds, Elymus nutans seeds, Elymus ovatus seeds, Artemisia chabuga seeds, Lespedeza velutipes seeds, Lespedeza davurica seeds and Rumex sorrel seeds in a volume ratio of (0.8-1):(0.8-1):(0.6-0.8):(0.2-0.3):(0.1-0.3):(0.1-0.3):(0.4-0.6);

[0012] The two-dimensional fertilizer consists of urea, potassium sulfate and mineral-source potassium humate.

[0013] In the present invention, the reason why organic fertilizer accounts for a larger proportion and inorganic fertilizer accounts for a smaller proportion in the ecological four-dimensional fertilizer is that the pH of the soil in the spoil dump of the alpine grassland mining area is alkaline, and inorganic fertilizer contains alkaline substances, which need to be used in small amounts on alkaline land, otherwise the soil pH will be too alkaline. Even if more organic fertilizer or other fertilizers are applied, it is difficult to avoid the negative effects of reduced soil effectiveness, damaged soil structure, and affected crop growth and development due to excessive soil alkalinity.

[0014] In the present invention, the ecological four-dimensional fertilizer is a high-efficiency compound fertilizer composed of organic farmyard manure, inorganic fertilizer, microbial fertilizer, and microecological fertilizer, which has unique advantages, that is, some functional microorganisms are endophytic symbiotic bacteria, which enter the plant body for colonization, reproduction and transfer, and have the functions of increasing yield, improving quality, enhancing resistance, preventing and controlling diseases and insects, reducing pollution, and purifying the environment. The functions of each fertilizer in the ecological four-dimensional fertilizer are:

[0015] ① Inorganic fertilizer (chemical fertilizer): Fertilizer composed of inorganic substances, mainly including single-element fertilizers such as nitrogen, phosphorus, potassium, compound fertilizers and trace elements.

[0016] ②Organic fertilizer: mainly farmyard manure fermented from cow dung, sheep dung, etc. According to the source and characteristics, different methods of accumulation can be used for targeted treatment.

[0017] ③ Microbial fertilizers: Microbial fertilizers mainly include rhizobia, nitrogen-fixing bacteria, phosphorus-solubilizing and potassium-solubilizing microorganisms and other beneficial microbial living fertilizers. The use of microbial fertilizers shall comply with the provisions of NY / T798-2015.

[0018] ④ Microecological medicinal fertilizer: Microecological medicinal fertilizer: Based on the principle of microecology, endophytic symbiotic microorganisms (such as Bacillus) are selected to adjust the individual microecological system of plants, and it has the functions of promoting growth, resisting stress, preventing aging and curing diseases. The microorganisms of microecological medicinal fertilizer are natural ecological members of plants. They colonize, reproduce and transfer in plants. Therefore, it is possible for it to have the functions of "fertilizer" and "medicine".

[0019] Preferably, the organic matter content in the organic fertilizer is 5%-35%; the total content of the nutrient elements N, P2O5 and K2O in the inorganic fertilizer is 12%-25%, and the content of trace elements is 1%-4%; the bacteria in the microbial fertilizer include at least one of rhizobia, nitrogen-fixing bacteria, phosphate-solubilizing microorganisms and potassium-solubilizing microorganisms, the bacterial content is 5%-10% (the remaining 90-95% is a carrier matrix commonly used in the art for carrying and preserving live bacteria), and the survival rate of the bacteria is 90%-95%; the bacteria in the microecological fertilizer are endophytic symbiotic microorganisms (preferably Bacillus), the bacterial content is 5%-10% (the remaining 90-95% is a carrier matrix commonly used in the art for carrying and preserving live bacteria), and the survival rate of the bacteria is 90%-95%; when applying ecological four-dimensional fertilizer, the soil moisture content is 7%-15%, and the soil pH value is 6.5-9.2; the fertilizer application rate of the ecological four-dimensional fertilizer is 1.8-2 tons / mu. The present invention does not particularly limit the types of trace elements in the inorganic fertilizer, which are trace elements conventionally contained in inorganic fertilizers in the art, such as: elements iron, manganese, copper, boron, molybdenum, selenium, silicon, etc., and medium elements calcium, magnesium, and sulfur.

[0020] Preferably, when rotary tillage and irrigation are performed, the depth of the rotary tillage is 15±1 cm; the irrigation is performed to a soil depth of 15±1 cm, so that the soil moisture content reaches 75%-77%.

[0021] Preferably, the sowing amount of the eco-bag is 22-25 kg / mu, and the sowing depth is 2-3 cm.

[0022] Preferably, the eco-bag is sown, and then irrigated, the irrigation is to irrigate to a soil depth of 10±1 cm, and the soil moisture content reaches 75%-77%. After sowing the eco-bag, it is necessary to observe the soil moisture during the greening period for irrigation and routine maintenance. The present invention does not specifically limit the amount of water used for irrigation during the greening period and the method of routine maintenance, and the technical solutions commonly used by those skilled in the art can be adopted according to the soil moisture.

[0023] Preferably, the topdressing is performed by spreading on the soil surface or spraying on the leaves.

[0024] Preferably, the urea fertilizer application amount is 11 kg / mu; the potassium sulfate fertilizer application amount is 8 kg / mu; the mineral source potassium humate fertilizer application amount is 10 kg / mu.

[0025] Preferably, when irrigation is performed immediately after spreading, the irrigation is performed until the soil depth reaches 5 cm and the soil moisture content reaches 75%-77%.

[0026] Preferably, when topdressing is performed when the plants reach the initial flowering stage in the following year, the amount and type of topdressing are consistent with those when topdressing is performed by spreading two-dimensional fertilizer when the plants reach the tillering stage.

[0027] The present invention discloses the following technical effects:

[0028] The present invention adopts a series of technical means such as applying ecological four-dimensional fertilizer, planting ecological bags, topdressing, and maintenance to achieve the purpose of improving the physical and chemical properties of the soil in the mine dump in the alpine grassland and improving the plant habitat conditions. After three years of practice, an effective micro-aggregate structure has been formed in the soil in the mine dump, and the vertical structure of the soil has been repaired while increasing humus, so that the soil such as gray alkaline soil, sandstone and mudstone has changed from gray and yellow to black gray and black yellow, and a 3-4 cm humus layer has been formed on the vegetation surface. Since the physical and chemical properties of the soil in the dump have been significantly improved, the soil has significantly increased the nutrients required for plant growth, and the vegetation restoration effect and the grass yield increase effect have been greatly improved. According to experimental observation and monitoring data statistics, the native vegetation in the experimental area has recovered to more than 124 species, with a coverage of 90%-95%, an average of 210 plants / square meter, fresh weight of forage yield of 1,357 kg / mu, dry weight of 310 kg / mu, hay that can be used for grass weighing 245 kg / mu, and seed yield of 8-9 kg / mu. This technology can not only stabilize the slope of the spoil dump where the abandoned stripping soil is piled up in the mining area and control soil erosion, but also improve the soil ecological environment, ensure the restoration effect of slope vegetation, and lead to the orderly succession and sustainable development of the entire ecosystem. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0031] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0032] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0033] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0034] In the present invention, the "%" in the organic matter content in the organic fertilizer, the total content of the nutrient elements N, P2O5 and K2O in the inorganic fertilizer, the content of trace elements and the bacterial content all represent mass percentage.

[0035] At present, there are few studies on soil habitats in grassland mining dumps in the high-altitude cold regions of northern my country. In the ecological restoration and management of grassland mining areas, there is a common phenomenon of focusing on increasing vegetation coverage while ignoring the improvement of soil habitats, focusing on short-term visible green effects while ignoring long-term sustainable effects, resulting in the consumption of a large amount of precious resources in the process of vegetation restoration, and even causing the destruction of soil habitats, which in turn causes vegetation degradation and forms a vicious cycle. The coordination of soil restoration and vegetation restoration in grassland mining areas is a necessary condition for the overall sustainable restoration of the ecology. The restoration of soil habitats in dumps is the basic guarantee for vegetation restoration. Open-pit coal mine dumps are reconstructed soil bodies, and their soil properties are very different from natural landform soils. How to improve the soil habitat state of dumps in high-altitude cold mining areas is the key to the success of ecological restoration.

[0036] The present invention screens out excellent plant varieties and plant configuration combinations that are suitable for overwintering under extreme low temperature conditions in alpine grassland mining areas, have local characteristics, are cold-resistant, drought-resistant, and salt-alkali-resistant, and summarizes the soil improvement method and soil improvement product of the dumping ground of open-pit coal mines in alpine grassland mining areas through experimental research. The present invention has strong practical significance for the sustainable restoration of dumping grounds in alpine grassland mining areas.

[0037] The present invention first clarifies the ecological management goal of the mine dump, conducts a systematic investigation on the soil system and habitat conditions of the mine dump in the alpine grassland, integrates the strengthening function of the soil structure during plant growth and the comprehensive effect of the ecological four-dimensional fertilizer, improves the physical and chemical properties of the soil in the mine dump, and improves the soil plant habitat conditions. With the vital plant roots, stems (branches) or the whole and microorganisms as the main factors of the soil system, supplemented by fertilizers and agents, mechanical disturbances and other factors, the soil structure of the mine dump is reorganized and reinforced during the plant growth and vegetation construction process, so as to achieve the purpose of improving the soil structure, increasing humus and controlling soil and water loss, and finally achieve the goal of stabilizing the dump slope and restoring vegetation. This technology can not only stabilize the dump slope of the mine waste stripping soil accumulation and control soil and water loss, but also ensure the restoration of slope vegetation and the repair of the vertical structure of the soil, resulting in the orderly succession and sustainable development of the entire ecosystem.

[0038] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0039] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0040] Example 1

[0041] 1. Investigation of habitat conditions of mine spoil dumps

[0042] The "remote sensing-ground" collaborative monitoring technology is used to systematically obtain basic information such as land characteristics, water system distribution, soil, vegetation type, etc. in the study area, analyze the natural geographical background characteristics and site type of the dump, understand the current status of the dump, conduct a detailed investigation of the longitude and latitude, and altitude of the dump, use a compass to measure the slope and slope direction, and measure the moisture and salt content of the dump matrix. Samples are taken from the surface soil (0-10cm), and the physical and chemical properties of the soil as well as the types and quantities of soil microorganisms are obtained through laboratory sample analysis.

[0043] The basic situation of the test area is as follows:

[0044] The test area belongs to the administrative region of Huaneng Yimin Open-pit Coal Mine, Yiminhe Town, Ewenki Autonomous Banner, Hulunbuir City, Inner Mongolia. The test plot was selected in the dumping ground (about 10 mu) where the abandoned stripping soil of Yimin Open-pit Coal Mine was piled up. It consists of slopes and platforms, and is a semi-sunny slope. The slope position is divided into the upper part of the slope and the middle part of the slope. The abandoned soil stripped from the mining area is loose in texture, mostly composed of sandstone, heavy and solid alkaline soil, coal gangue, etc. The surface characteristics are that the slope is 25°-30°, there is no fallen leaves, no covering soil, wind erosion and water erosion often occur, causing underground, surface water and atmospheric dust pollution. The grassland ecology around the test plot is severely damaged, soil degradation, surface destruction, and geological structure changes caused by mining, which makes the soil physical and chemical properties of the dumping ground poor, nutrient-poor, and even toxic and harmful substances distributed in the soil. Due to the large scale and long period of mining in the Yimin open-pit coal mine, the soil is poor and has a high content of heavy metals, so it is difficult to cover a large area with soil and improve the imported soil. As a result, the proportion of bare land is large, and the ability to retain rainfall and irrigation water is poor. Due to local climatic conditions and other reasons, the irrigation system is less stable, and unstable water pressure is prone to pipe bursts and freezing cracks.

[0045] 2. Soil improvement plan

[0046] Step 1. In mid-May (May 10), ecological four-dimensional fertilizer was spread on the soil surface of the above-mentioned test plot, and then the soil was turned into the soil with a rotary tiller. The rotary tillage depth was about 15 cm, the fertilizer application rate was 2 tons / mu, and irrigation was carried out. Irrigation was carried out to a soil depth of 15 cm to make the soil moisture content reach 75%-77%; the ecological four-dimensional fertilizer was composed of organic fertilizer, inorganic fertilizer, microbial fertilizer and microecological fertilizer (by mass percentage, the mass ratios of organic fertilizer, inorganic fertilizer, microbial fertilizer and microecological fertilizer to ecological four-dimensional fertilizer were: 50%, 20%, 20%, 10%), among which, the organic matter content in the organic fertilizer is 35%, the total content of the nutrient elements N, P2O5 and K2O in the inorganic fertilizer is 25%, and the content of trace elements is 4%; the bacteria in the microbial fertilizer are rhizobia, nitrogen-fixing bacteria, phosphate-solubilizing microorganisms and potassium-solubilizing microorganisms, with a bacterial content of 10% and a survival rate of 95%; the bacteria in the microecological fertilizer are Bacillus, with a bacterial content of 10% and a survival rate of 95%; when applying ecological four-dimensional fertilizer, the soil moisture content is 7%-15%, and the soil pH value is 6.5-9.2.

[0047] Step 2. After the base fertilizer is applied and irrigation is carried out, the land is prepared, and the selected native plant varieties with good cold resistance, drought resistance, safe wintering in the northern alpine grassland mining area, strong stress resistance and other characteristics are matched to form an ecological bag for artificial sowing. The ecological bag is composed of ryegrass seeds, drooping spike alkali grass seeds, thin wheat grass seeds, Artemisia argyi seeds, fluffy Lespedeza seeds, Dauri Lespedeza seeds and Rumex seeds in a volume ratio of 1:1:0.8:0.3:0.3:0.3:0.6; the plant seeds are mixed and sown, with a sowing rate of 25kg / mu and a sowing depth of 2 to 3 cm. Cover with straw mats immediately after sowing, and then irrigate and water until the soil moisture content reaches 75%-77% at a soil depth of 10 cm. During the green period, observe the surface soil moisture for irrigation and routine maintenance.

[0048] Step 3. Select two-dimensional fertilizers (urea, potassium sulfate and mineral potassium humate) as topdressing. In the first year, topdressing is carried out when the plants planted in the dumping field grow to the tillering (branching) stage. The fertilizer is spread on the surface of the soil. The fertilizer amount is 11 kg / mu of urea, 8 kg / mu of potassium sulfate + 10 kg / mu of mineral potassium humate. Water immediately after spreading until the soil moisture content reaches 75%-77% at a soil depth of 5 cm. In the second year, topdressing is carried out when the plant growth reaches the initial flowering stage. The amount of topdressing is the same as in the first year. In the third year, topdressing is carried out when the plant growth reaches the initial flowering stage. The amount of topdressing is the same as in the first year.

[0049] 3. Soil improvement effect of mine spoil dump

[0050] In the above-mentioned test plots, the application of ecological four-dimensional fertilizer has obvious effects on the improvement of soil structure and soil improvement in the dumping ground dominated by waste stripping soil such as sandstone, alkaline soil, and coal gangue. The main performances are: the conversion rate of effective degradation of vegetation dead branches and leaves is increased, and a 3-4 cm humus layer is formed on the surface of the dumping ground after three years of use; the color of the soil in the dumping ground changes from white-gray to black-gray and black-yellow, effective micro-aggregates have been formed in the soil structure, the soil porosity has been improved, the surface layer has become solid, and the soil organic matter content has increased. After three years of test data, it has been proved that this technology can effectively improve the physical and chemical properties of the soil in the dumping ground of the open-pit coal mine in the grassland mining area, and improve the soil supply of water and nutrient elements required for plant growth. The purpose of transport absorption and utilization, thereby achieving the purpose of improving soil structure, increasing humus and controlling soil and water loss, and finally achieving the goal of stabilizing the slope of the dumping ground and restoring vegetation. The test results are shown in Table 1.

[0051] Table 1. Soil test table of the dumping site in Yimin open-pit coal mine

[0052]

[0053] As can be seen from Table 1, the comparison of the soil test results of the spoil dump where the stripping soil is accumulated in the Yimin open-pit mine area (May 2021) and the "Soil Nutrient and PH Value Grading Standard" shows that the soil in the spoil dump where the stripping soil is accumulated before the experiment started was strongly alkaline, with extremely low organic matter (grade 6), extremely low effective phosphorus (grade 6), low available potassium content (grade 5), and extremely low hydrolyzable nitrogen content (grade 6); the electrical conductivity exceeded the normal soil electrical conductivity (0.05-0.7ms / m), and the value was too large, indicating that a large amount of salt substances were accumulated in this type of soil at that time, which accelerated the evaporation rate of soil water, ultimately leading to low soil fertility, which greatly affected the plant's absorption of soil nutrients and water, resulting in poor soil habitat conditions, and causing most plants to be unable to grow normally.

[0054] In the practice of ecological management of the spoil dump where stripped soil is accumulated in the Yimin open-pit mine area, after three years of implementation of the technical plan for soil improvement in the spoil dump, the test results show that the physical and chemical properties of the soil in the spoil dump have been significantly improved, and the soil has significantly increased the nutrients required for plant growth. The soil test data in May 2023 was compared with the "Soil Nutrient and PH Value Classification Standard" and showed that the soil in the spoil dump where stripped soil is accumulated in the Yimin open-pit mine area is neutral, with extremely high organic matter (level 1), medium effective phosphorus (level 4), high available potassium content (level 1), and medium hydrolyzable nitrogen content (level 4); the electrical conductivity is within the normal soil conductivity range (0.05-0.7ms / m). The test results prove that through soil improvement technical measures, the salt substances in the soil of the spoil dump are effectively alleviated and reduced in the alkalinity and viscosity of the soil layer through transportation, metabolism, decomposition, dilution, and degradation during plant growth.

[0055] 4. Vegetation restoration and grass yield increase effect

[0056] In the study of ecological management and vegetation restoration technology in alpine grassland mining areas, the dumping ground of Yimin open-pit mining area with abandoned stripping soil such as sandstone, alkaline soil and coal gangue was selected as the test site. By combining soil improvement technology with native plant configuration technology, good vegetation restoration effect and grass yield increase effect were achieved. According to experimental observation and monitoring data statistics, the emergence rate, plant height, root penetration depth, number of branches (tillers) / plant and vegetation coverage of planted grass seeds have all improved, proving that the implementation of this soil improvement technology has effectively enhanced the cold, drought and disease resistance of plants, provided good habitat conditions for perennial plant community species and companion species, and significantly enhanced the overall effect of vegetation restoration in the dumping ground. Not only did it improve the plant diversity and grass yield after the vegetation community was established in the dumping ground, but the growth and yield of some species also exceeded that of natural grasslands. The comparison data of vegetation growth after the application of ecological four-dimensional fertilizer and other fertilizers in the dumping ground are shown in Table 2. The statistical data on plant diversity and grass yield after applying ecological four-dimensional fertilizer and other fertilizers to natural grassland soil in high-altitude areas are shown in Table 3.

[0057] Table 2. Comparative data of plant growth after applying ecological four-dimensional fertilizer and other fertilizers to the soil of the dumping ground

[0058]

[0059]

[0060] Note: Other fertilizers used include humic acid fertilizer 10-14kg / mu, covering soil 5-8cm, and additional farmyard manure 2.8-3.1 tons / mu.

[0061] Table 3. Comparative statistics of plant diversity and grass yield after applying ecological four-dimensional fertilizer and other fertilizers to natural grassland soil

[0062]

[0063]

[0064] In summary, in the study of ecological management and vegetation restoration technology in alpine grassland mining areas, the present invention selected the dumping ground of the Yimin open-pit mine area with abandoned stripping soil such as sandstone, alkaline soil, and coal gangue as the test plot, and adopted a series of technical means such as applying ecological four-dimensional fertilizers, planting ecological bags, topdressing, and maintenance to achieve the purpose of improving the physical and chemical properties of the soil in the mining area dumping ground and improving the plant habitat conditions. After three years of practice, an effective micro-aggregate structure has been formed in the soil of the mining area dumping ground, and the vertical structure of the soil has been repaired while increasing humus, so that the soil such as gray alkaline soil, sandstone and mudstone has changed from gray and yellow to black gray and black yellow, and a 3-4 cm humus layer has been formed on the vegetation surface. Because the physical and chemical properties of the soil in the dumping ground have been significantly improved, the soil supply of nutrients required for plant growth has been significantly improved, and the vegetation restoration effect and the grass yield increase effect have been greatly improved. According to experimental observation and monitoring data statistics, the native vegetation in the experimental area has recovered to more than 124 species, with a coverage of 90%-95%, an average of 210 plants / square meter, fresh weight of forage yield of 1,357 kg / mu, dry weight of 310 kg / mu, hay that can be used for grass weighing 245 kg / mu, and seed yield of 8-9 kg / mu. This technology can not only stabilize the slope of the spoil dump where the abandoned stripping soil is piled up in the mining area and control soil erosion, but also improve the soil ecological environment, ensure the restoration effect of slope vegetation, and lead to the orderly succession and sustainable development of the entire ecosystem.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving soil in a mine dump in an alpine grassland, characterized in that: The following steps are involved: Step 1, select ecological four-dimensional fertilizer as base fertilizer, apply fertilizer in mid-May, and then perform rotary tillage and irrigation; Step 2: After irrigation, prepare the land, spread the eco-bags, and then irrigate; Step 3, when the plants grow to the tillering stage, apply two-dimensional fertilizer as topdressing, and irrigate immediately after applying; the next year, when the plants grow to the initial flowering stage, apply topdressing; the topdressing lasts for 3 years in total; The ecological four-dimensional fertilizer is composed of organic fertilizer, inorganic fertilizer, microbial fertilizer and microecological fertilizer, wherein, by mass percentage, the mass ratios of organic fertilizer, inorganic fertilizer, microbial fertilizer and microecological fertilizer to the ecological four-dimensional fertilizer are 50%, 20%, 20% and 10% respectively; The eco-bag is composed of ryegrass seeds, Elymus nutans seeds, Elymus ovatus seeds, Artemisia chabuga seeds, Lespedeza velutipes seeds, Lespedeza davurica seeds and Rumex sorrel seeds in a volume ratio of (0.8-1):(0.8-1):(0.6-0.8):(0.2-0.3):(0.1-0.3):(0.1-0.3):(0.4-0.6); The two-dimensional fertilizer consists of urea, potassium sulfate and mineral-source potassium humate.

2. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: The organic fertilizer contains 5%-35% organic matter; the inorganic fertilizer contains 12%-25% nutrient elements N, P2O5 and K2O, and the trace element content is 1%-4%; the microorganisms in the microbial fertilizer include at least one of rhizobia, nitrogen-fixing bacteria, phosphate-solubilizing microorganisms and potassium-solubilizing microorganisms, with a bacterial content of 5%-10% and a survival rate of 90%-95%; the microecological fertilizer contains endophytic symbiotic microorganisms with a bacterial content of 5%-10% and a survival rate of 90%-95%; when applying the ecological four-dimensional fertilizer, the soil moisture content is 7%-15% and the soil pH value is 6.5-9.2; the application amount of the ecological four-dimensional fertilizer is 1.8-2 tons / mu.

3. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: When rotary tillage and irrigation are performed, the depth of the rotary tillage is 15±1 cm; the irrigation is performed to a soil depth of 15±1 cm, so that the soil moisture content reaches 75%-77%.

4. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: The sowing amount of the eco-bag is 22-25 kg / mu, and the sowing depth is 2-3 cm.

5. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: The eco-bag is spread and then irrigated to a soil depth of 10±1 cm and the soil moisture content reaches 75%-77%.

6. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: The topdressing method is spreading on the soil surface or spraying on the leaves.

7. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: The application amount of urea is 11 kg / mu; the application amount of potassium sulfate is 8 kg / mu; and the application amount of mineral potassium humate is 10 kg / mu.

8. The method for improving soil in a mine dump in an alpine grassland according to claim 1, characterized in that: When irrigation is carried out immediately after spreading, irrigate to a soil depth of 5 cm and until the soil moisture content reaches 75%-77%.

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