Method for rapid vegetation recovery and construction of abandoned slag field in alpine high-altitude area

Abstract

The application discloses a method for rapid vegetation recovery and construction of a slag yard in an alpine high-altitude area, which comprises the following steps: step 1, screening slag soil to obtain slag soil powder; step 2, mixing the slag soil powder with fertilizer and a compound microbial agent to prepare pretreated slag soil powder; step 3, mixing pretreated seeds with the pretreated slag soil powder and spraying the mixture on the slag yard to form a cover layer; and step 4, watering the cover layer so that the water content in the cover layer is 25-35%. According to the combined mechanism of plants-microorganisms-nutritional elements, the stability and physicochemical properties of the slag soil are changed, and according to subsequent tests, it is found that, after the method is implemented, the slag soil is in a state of adhesion and soil gum.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology for slag heaps, specifically to a method for rapid vegetation restoration and establishment in slag heaps in high-altitude and cold regions. Background Technology

[0002] New tunnel construction generates a large amount of construction waste, which, due to high transportation costs, is typically dumped on-site, forming waste disposal sites. These sites suffer from nutrient deficiencies, unique soil structures, and limited microbial communities, making them difficult for native vegetation to spread naturally, hindering vegetation growth and causing severe ecological damage. In recent years, my country has placed increasing emphasis on ecological environmental protection, leading to a growing need for technologies that enable rapid vegetation establishment in waste disposal sites.

[0003] In recent years, some scholars have proposed that spoil heaps can be remediated using topsoil, covering the spoil with a certain thickness of topsoil before land reclamation or vegetation transplantation. Others have suggested shoveling up about 30cm of topsoil before tunnel construction and stockpiling it within the spoil heap area. After construction, the soil and spoil are leveled, and the stripped topsoil is covered for land reclamation and greening. Still other researchers have proposed material-based remediation, mixing modified materials with spoil and covering it to retain water and soil, thus achieving ecological restoration. In summary, current research on spoil heap remediation mainly focuses on topsoil or topsoil reclamation, ensuring that the spoil can still meet the germination and growth needs of plants for a period of time, thereby restoring the ecosystem and retaining water and soil.

[0004] Problems with existing repair technologies: 1. The soil structure of the spoil heap is unique, with a large number of large stones and a small amount of fine soil. Existing technologies make it difficult for plants to take root and the soil has extremely poor water retention.

[0005] 2. Nowadays, the remediation of spoil heaps mainly relies on topsoil remediation, which mainly involves taking soil from other places or taking topsoil from the mountain surface. However, the amount of topsoil from the mountain is very small, and other topsoil often needs to be transported for covering, which increases the remediation cost.

[0006] 3. The harsh climate conditions in high-altitude and cold regions, coupled with the extremely poor nutrient elements in the slag soil, make it difficult for plants to grow even when using local native plants and conventional remediation methods.

[0007] Therefore, it is extremely necessary to explore ways to quickly restore and replant vegetation at spoil heaps of shield tunnels in high-altitude and cold regions. Summary of the Invention

[0008] To address the problems of difficult plant rooting, high costs, and difficulty in plant growth in existing technologies for spoil disposal site remediation, the purpose of this invention is to provide a method for rapid vegetation restoration and establishment in spoil disposal sites in high-altitude and cold regions.

[0009] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A method for rapid vegetation restoration and replanting at spoil heaps in high-altitude and cold regions includes the following steps: Step 1: Sift the slag to obtain slag powder; Step 2: Mix the slag powder with fertilizer and compound microbial agent to obtain pretreated slag powder; Step 3: Mix the pretreated seeds with the pretreated slag powder and spray it onto the slag yard to form a covering layer; Step 4: Water the cover layer to bring the moisture content to 25-35%.

[0010] Based on the above technical solution, the present invention can be further improved as follows: Furthermore, the effective viable bacteria count in the compound microbial agent is 900-1200 billion / m³. 2 .

[0011] Furthermore, the compound microbial agent includes at least two of Aspergillus niger, Trichoderma harzianum, and Bacillus licheniformis.

[0012] Furthermore, the pretreated seeds include a sticky shell, a modified slow-release fertilizer located inside the shell, and modified seeds located inside the shell and attached to the surface of the modified slow-release fertilizer.

[0013] Furthermore, by weight, the shell comprises: 18-40 parts gelatin and 25-48 parts sodium alginate.

[0014] Furthermore, the modified slow-release fertilizer includes a base slow-release fertilizer, a connecting layer coated on the surface of the base slow-release fertilizer, and pretreated slag powder attached to the surface of the connecting layer. Modified seeds include seeds and an adhesive layer covering the surface of the seeds.

[0015] Furthermore, by weight, the connecting layer comprises: 50-70 parts gelatin, 18-28 parts polyethylene glycol, 3-7 parts starch, and 1-3 parts rooting solution; By weight, the adhesive layer comprises: 50-70 parts gelatin and 18-28 parts polyethylene glycol.

[0016] Furthermore, the seeds include at least one of ryegrass seeds, tall fescue seeds, and crested wheatgrass seeds.

[0017] Furthermore, in step 3, the thickness of the covering layer is 5-10cm; 18-25g of seeds are sown per square meter of the slag heap. The fertilizer used in step 1 is slow-release fertilizer, with 100-180g of slow-release fertilizer per square meter of slag yard.

[0018] Furthermore, the particle size of the slag powder is less than 5 mm.

[0019] The present invention has the following beneficial effects: 1. In this invention, the stability and physicochemical properties of the slag soil are changed through the combined mechanism of "plant-microorganism-nutrient elements". According to subsequent tests, after implementing the method in this invention, the slag soil showed adhesion and soil colloids.

[0020] 2. In this invention, the seeds are pretreated to promote their adhesion to the slag soil, which to some extent promotes the seeds to take root on the slag soil and reduces the problem of difficult rooting in existing remediation technologies. At the same time, the modified slow-release fertilizer and pretreated slag soil powder in the pretreated seeds provide the necessary nutrients and root attachment points for the early growth of the seeds, which reduces the difficulty of plant growth to some extent. Attached Figure Description

[0021] Figure 1 This is a particle size distribution diagram of the slag in the slag yard; Figure 2 Figure 1 shows the results of the detection of native microbial community in the slag yard. Figure 2 shows the results of the detection of native bacteria in the slag yard, and Figure 3 shows the results of the detection of native fungi in the slag yard. Figure 3 This is a flowchart illustrating the method for rapid vegetation restoration and replanting in this invention. Figure 4 This is a diagram showing the germination results of the seeds; Figure 5 Figures showing the test results for aboveground and belowground biomass; Figure 6 The pH value diagram of the slag soil; Figure 7 This is a diagram showing the growth of plant buds and roots. Figure 8 The graph shows the results of soil moisture content. Figure 9 This is a SEM image of the original slag soil. Figure 10 SEM images of the slag soil after 90 days in the method embodiment of Comparative Example 1; Figure 11 This is a SEM image of the slag soil after 90 days in the method embodiment of Example 1; Figure 12 This is a SEM image of the slag soil after 90 days in the method example of Example 2. Detailed Implementation

[0022] The following description, in conjunction with embodiments, illustrates a method for rapid vegetation restoration and establishment at spoil heaps in high-altitude and cold regions. However, this application may be exemplified in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of this application to those skilled in the art.

[0023] The inventor has extensive experience in the field of vegetation restoration of slag heaps. Based on this, the inventor previously analyzed the physicochemical properties of slag soil, its nutrient content, and the microbial community composition in slag heaps located in high-altitude and cold regions. Details of the physicochemical property tests for the slag heaps can be found in [link to relevant documentation]. Figure 1 ,from Figure 1 As can be seen from Table 1, the slag dump mainly consists of large stones with a particle size of around 100mm, with very little small-sized slag. Furthermore, Table 1 shows that the primary slag in the slag dump is also low in nutrients. Figure 2 It can also be seen that the microbial community of the original spoil soil is relatively simple. This indicates that spoil disposal sites for shield tunneling in high-altitude and cold regions are not suitable for plant growth.

[0024] Table 1. Nutrient content of raw waste soil

[0025] Therefore, there is an urgent need for a method that can effectively and quickly restore vegetation at spoil disposal sites of shield tunnels in high-altitude and cold regions.

[0026] An embodiment of the present invention provides a method for rapid vegetation restoration and establishment in spoil heaps in high-altitude and cold regions, comprising the following steps: Step 1: Sift the slag to obtain slag powder; Step 2: Mix the slag powder with fertilizer and compound microbial agent to obtain pretreated slag powder; Step 3: Mix the pretreated seeds with the pretreated slag powder and spray it onto the slag yard to form a covering layer; Step 4: Water the cover layer to bring the moisture content to 25-35%.

[0027] In this invention, a combined matrix of "plants-microorganisms-nutrients" is used to change the internal stability and physicochemical properties of the slag soil, transforming it into a form that is conducive to plant growth, and ultimately restoring the vegetation in the slag yard.

[0028] In this embodiment, the slag powder in step 1 is obtained by passing the slag from the slag yard through a 5mm sieve. Furthermore, the fertilizer in step 2 is mainly slow-release fertilizer, which is a common fertilizer on the market, such as Stanley slow-release fertilizer. In this embodiment, 100-180g of slow-release fertilizer is applied per square meter of the slag yard. The slow-release fertilizer provides nutrients for plant growth. In addition, plants in high-altitude and cold regions grow slowly, and the slow release of the slow-release fertilizer is beneficial to plant growth in these areas.

[0029] In addition, in step 2, a compound microbial agent is added to the slag powder. In some embodiments, the effective viable bacteria count in the compound microbial agent is 900-1200 billion / m³. 2 Preferably, the effective viable bacteria count in the compound microbial agent is 100 billion / m³. 2 .

[0030] Furthermore, the compound microbial agent in this embodiment includes at least two of Aspergillus niger, Trichoderma harzianum, and Bacillus licheniformis. Aspergillus niger can cleave large organic molecules and insoluble inorganic substances, facilitating crop absorption and utilization, improving soil structure, enhancing soil fertility, and increasing crop yield. Trichoderma harzianum has the ability to prevent plant diseases caused by pathogens such as Pythium, Rhizoctonia solani, Fusarium, Rhizopus niger, Columnar spores, Sclerotinia sclerotiorum, and Sclerotium licheniformis. Bacillus licheniformis has the ability to solubilize potassium, releasing soluble phosphorus and potassium elements, as well as trace elements such as calcium, sulfur, protactinium, iron, zinc, molybdenum, and manganese. Therefore, adding the compound microbial agent to slag powder can promote slag decomposition, release usable nutrients from the slag, and also prevent plant diseases to a certain extent, further promoting plant growth.

[0031] Preferably, the compound microbial agent in this invention is composed of Bacillus licheniformis and Trichoderma harzianum in a mass ratio of 1:1.

[0032] In some embodiments, the pretreated seeds include an adhesive shell, a modified slow-release fertilizer inside the shell, and modified seeds located inside the shell and attached to the surface of the modified slow-release fertilizer. In this embodiment, pretreatment of the seeds promotes adhesion between the seeds and the slag soil, ultimately enabling them to take root and germinate on the slag soil, thus restoring vegetation in the slag mine.

[0033] The shell, by weight, comprises 18-40 parts gelatin and 25-48 parts sodium alginate. In this invention, both gelatin and sodium alginate are biodegradable, with sodium alginate degrading more slowly than gelatin. This mass ratio of gelatin to sodium alginate provides a suitable degradation time, which is beneficial for seed germination within the shell. It also avoids excessive gelatin content, which would lead to a shorter degradation time and premature exposure of the seeds to a cold environment, hindering seed development. Preferably, by weight, the shell comprises 27 parts gelatin and 33 parts sodium alginate. Furthermore, in this embodiment, using gelatin and sodium alginate as the shell, the gelatin in the shell swells and melts upon contact with water, generating adhesiveness that allows the pretreated seeds to adhere to the slag soil, facilitating seed rooting.

[0034] In some embodiments, the modified slow-release fertilizer includes a base slow-release fertilizer, a connecting layer coated on the surface of the base slow-release fertilizer, and pretreated slag powder attached to the surface of the connecting layer; wherein, by weight, the connecting layer includes: 50-70 parts gelatin, 18-28 parts polyethylene glycol, 1-3 parts rooting hormone, and 3-7 parts starch. In this embodiment, the base slow-release fertilizer is a commercially available slow-release fertilizer, such as the aforementioned Stanley slow-release fertilizer. In this embodiment, the gelatin and polyethylene glycol in the connecting layer are both biodegradable substances, and the gelatin has a relatively fast degradation rate. Therefore, after the shell of the pretreated seed degrades, the connecting layer in the modified slow-release fertilizer inside the shell can quickly disintegrate, releasing the internal basic slow-release fertilizer to provide nutrients for the early growth of the plant. In addition, both gelatin and polyethylene glycol have good adhesion. After the shell degrades, they can adhere the modified seed and the pretreated slag powder attached to the surface to the slag soil in the slag yard. Furthermore, the pretreated slag powder provides attachment points in the early stage of seed root growth, facilitating the later root growth of the seed on the slag soil. Preferably, by weight, the connecting layer includes: 62 parts gelatin, 21 parts polyethylene glycol, 2 parts rooting solution, and 5 parts starch.

[0035] In some embodiments, the modified seed includes the seed itself and an adhesive layer coating the seed surface; wherein, by weight, the adhesive layer comprises 50-70 parts gelatin and 18-28 parts polyethylene glycol. In this invention, the adhesive layer adheres the seed to the modified slow-release fertilizer, thereby ensuring that the slow-release fertilizer directly provides nutrients for the seed's germination and growth. The preparation of the pretreated seed in this embodiment includes the following steps: Step S1: Preparation of modified slow-release fertilizer By weight, 50-70 parts of gelatin, 18-28 parts of polyethylene glycol, 1-3 parts of rooting water and 3-7 parts of starch are first dissolved in an aqueous solution at 35-45°C to prepare a mixture. The mixture is then sprayed onto the base slow-release fertilizer and finally dried naturally to obtain the modified slow-release fertilizer intermediate. Modified slow-release fertilizer intermediates are mixed with pretreated slag powder, added to 38-42°C and stirred, and then cooled to room temperature to obtain modified slow-release fertilizer.

[0036] Step S2: Preparation of modified seeds By weight, 50-70 parts of gelatin and 18-28 parts of polyethylene glycol are dissolved in an aqueous solution at 35-45°C to prepare a mixture. The mixture is then mixed with seeds by spraying and cooled to room temperature to obtain modified seeds.

[0037] Step S3: Preparation of pretreated seeds The modified seeds from step S2 and the modified slow-release fertilizer from step S1 are mixed, heated to 38-42°C and stirred, and then cooled to room temperature to obtain an intermediate product in which the modified seeds are attached to the surface of the modified slow-release fertilizer. By weight, 18-40 parts of gelatin and 25-48 parts of sodium alginate are dissolved in an aqueous solution at 35-45°C to prepare a mixture. Then, 5-8 parts of calcium chloride are added, and the mixture is quickly mixed and sprayed onto the surface of the intermediate product on which the modified seeds are attached to the surface of the modified slow-release fertilizer. After drying, pretreated seeds are obtained.

[0038] In some embodiments, the seeds include at least one of ryegrass seeds, tall fescue seeds, and crested wheatgrass seeds. In this embodiment, the aforementioned seeds are suitable for growth in high-altitude and cold environments, which is beneficial for the restoration of vegetation in the slag heap. Preferably, the seeds consist of tall fescue seeds, ryegrass seeds, and crested wheatgrass seeds in a mass ratio of 3:1:1.

[0039] In addition, in some embodiments, the thickness of the covering layer in step 3 is 5-10cm; 18-25g of seeds are sown per square meter of slag yard; the fertilizer in step 1 is slow-release fertilizer, and 5-15g of slow-release fertilizer is applied per square meter of slag yard.

[0040] Example Example 1: A method for rapid vegetation restoration and establishment in spoil heaps in high-altitude and cold regions, comprising the following steps: Step 1: Take a portion of the waste soil and pass it through a 5mm sieve to obtain waste soil powder; Step 2: Mix the slag powder with slow-release fertilizer (Stanley slow-release fertilizer) and compound microbial agent at a mass ratio of 1000:100:6 to obtain pretreated slag powder; wherein, 100g of slow-release fertilizer is added per square meter of slag yard, and the compound microbial agent consists of Bacillus licheniformis and Trichoderma harzianum at a mass ratio of 1:1, and the effective viable count of the compound microbial agent is 100 billion / m³. 2 .

[0041] Step 3: Mix the pretreated seeds and pretreated slag powder at a mass ratio of 1:5, and spray the mixture onto the slag yard to form a cover layer with a thickness of 8 cm; wherein, 20g of seeds are sown per square meter of slag yard; the preparation of pretreated seeds includes the following steps: Step S1: Preparation of modified slow-release fertilizer By weight, 62 parts of gelatin, 21 parts of polyethylene glycol, 2 parts of rooting water and 5 parts of starch were first dissolved in an aqueous solution at 38°C to prepare a mixture. The mixture was then sprayed onto 250 parts of basic slow-release fertilizer (Stanley slow-release fertilizer) and finally dried naturally to obtain a modified slow-release fertilizer intermediate. Modified slow-release fertilizer intermediates and pretreated slag powder were mixed at a mass ratio of 2:9, added to 40°C and stirred, and then cooled to room temperature to obtain modified slow-release fertilizer.

[0042] Step S2: Preparation of modified seeds By weight, 59 parts of gelatin and 25 parts of polyethylene glycol were dissolved in an aqueous solution at 38°C to prepare a mixture. The mixture was then mixed with 160 parts of seeds by spraying and cooled to room temperature to obtain modified seeds.

[0043] Step S3: Preparation of pretreated seeds The modified seeds in step S2 and the modified slow-release fertilizer in step S1 are mixed at a mass ratio of 5:3, heated to 40°C and stirred, and then cooled to room temperature to obtain an intermediate product in which the modified seeds are attached to the surface of the modified slow-release fertilizer. By weight, 28 parts of gelatin and 39 parts of sodium alginate were first dissolved in an aqueous solution at 38°C to prepare a mixture. Then, 6 parts of calcium chloride were added, and the mixture was quickly mixed and sprayed onto the surface of the intermediate product of 74 parts of modified seeds attached to the surface of modified slow-release fertilizer. After drying, pretreated seeds were obtained.

[0044] Step 4: Water the cover layer to bring the moisture content to 32%.

[0045] Example 2 The method for rapid vegetation restoration and establishment in a high-altitude, cold region in this embodiment is the same as that in Embodiment 1, except that 180g of slow-release fertilizer is added per square meter of the waste disposal site in step 2.

[0046] Comparative Example 1 A method for rapid vegetation restoration and replanting in spoil heaps in high-altitude and cold regions includes the following steps: Step 1: Take a portion of the waste soil and pass it through a 5mm sieve to obtain waste soil powder; Step 2: Mix the seeds with the slag powder and spray it onto the slag yard to form a cover layer with a thickness of 8cm; 20g of seeds are sown per square meter of slag yard. Step 3: Water the cover layer to bring the moisture content to 32%.

[0047] Test Analysis: 1. Seed germination rate, biomass, pH value, shoot and root length, and soil moisture content at different stages were tested and analyzed in Examples 1, 2, and Comparative Example 1. The test results are shown in the figures below. Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 .

[0048] from Figure 4 It can be seen that the method in this invention has a high germination rate; from Figure 5 As can be seen, the method of this invention increases the amount of above-ground and below-ground organisms in the slag heap; from Figure 6 As can be seen, the method in this invention does not cause a change in the pH value of the slag; from Figure 7 As can be seen, plants grown using the method of this invention have longer buds and roots, indicating that the method of this invention is beneficial to plant growth; from Figure 8 As can be seen, the method in this invention can increase the moisture content of the slag and soil, thereby altering its physical properties to a certain extent.

[0049] 2. Tests and analyses were conducted on the original waste soil and the waste soil after 90 days of treatment using the methods in Comparative Example 1, Example 2, and Example 1. Figure 9 This is a graph showing the test results of the original waste soil. Figure 10 This is a graph showing the soil test results after 90 days in the method example of Comparative Example 1. Figure 11 This is a graph showing the soil test results after 90 days of implementation of the method in Example 1. Figure 12 The graph shows the test results of the slag and soil after 90 days of implementation of the method in Example 2.

[0050] from Figure 10 It can be seen that the soil in Comparative Example 1 does not change much, and is mainly composed of loose, flaky structures; from Figure 11 It can be seen that there is a small amount of adhesion between the slag and soil; from Figure 12 As can be seen, soil colloids are present in the slag soil; the above results indicate that the method of the present invention is beneficial to improving the properties of slag soil, transforming it in a direction conducive to plant growth, and ultimately promoting plant growth.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rapid vegetation restoration and replanting in spoil heaps in high-altitude and cold regions, characterized in that, Includes the following steps: Step 1: Sift the slag to obtain slag powder; Step 2: Mix the slag powder with fertilizer and compound microbial agent to obtain pretreated slag powder; Step 3: Mix the pretreated seeds with the pretreated slag powder and spray it onto the slag yard to form a covering layer; Step 4: Water the covering layer until the moisture content is 25-35%. The pretreated seeds include a sticky shell, a modified slow-release fertilizer located inside the shell, and modified seeds located inside the shell and attached to the surface of the modified slow-release fertilizer. By weight, the shell comprises: 18-40 parts gelatin and 25-48 parts sodium alginate; The modified slow-release fertilizer includes a base slow-release fertilizer, a connecting layer coated on the surface of the base slow-release fertilizer, and pretreated slag powder attached to the surface of the connecting layer. The modified seed includes a seed and an adhesive layer covering the surface of the seed; By weight, the connecting layer comprises: 50-70 parts gelatin, 18-28 parts polyethylene glycol, 3-7 parts starch, and 1-3 parts rooting solution; The adhesive layer comprises, by weight, 50-70 parts gelatin and 18-28 parts polyethylene glycol.

2. The method according to claim 1, characterized in that, The compound microbial agent includes at least two of Aspergillus niger, Trichoderma harzianum, and Bacillus licheniformis.

3. The method according to claim 1, characterized in that, The seeds include at least one of ryegrass seeds, tall fescue seeds, and crested wheatgrass seeds.

4. The method according to claim 3, characterized in that, In step 3, the thickness of the covering layer is 5-10cm; 18-25g of seeds are sown per square meter of the slag yard. The fertilizer used in step 2 is a slow-release fertilizer, and 100-180g of slow-release fertilizer is applied per square meter of the slag yard.

5. The method according to any one of claims 1 to 4, characterized in that, The particle size of the slag powder is less than 5 mm.

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