A soil matrix containing mud cake, its preparation method and its application in ecological restoration

Abstract

This invention relates to the field of ecological technology, specifically disclosing a soil matrix containing mud cake, its preparation method, and its application in ecological restoration. The soil matrix of this invention comprises a solid mixture and water. The solid mixture includes: 0.005%-0.01% nitrogen-fixing compound bacterial agent, 20%-45% organic compound slow-release material, 25%-40% mud cake, 28%-42% deep subsoil, 0.05%-0.1% cationic polyacrylamide, and 0.2%-0.4% vinyl acetate-ethylene carbonate copolymer; the nitrogen-fixing compound bacterial agent includes rhizobia, Azotobacter chrysophyllariae, Bacillus megaterium, and Azospirillum; the organic compound slow-release material includes organic fertilizer, wood flour, and fertilizer. This invention fully utilizes the large amount of mud cake generated in hydropower development and other projects, developing it into a substrate suitable for plant growth, especially providing a platform and carrier for plant growth on slopes, saving land resources, and possessing advantages such as high operability, low cost, and good ecological restoration effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ecology, in particular to a soil matrix containing mud cake and a preparation method thereof and application in ecological restoration. BACKGROUND

[0002] In the construction process of a water power station, a large amount of sand and stone aggregate is generated by tunnel excavation, and a large amount of concentrated mud slurry is generated by wastewater recovery of a sandstone processing system. The mud slurry is pressurized by a slurry pump to a filter press workshop, and the mud slurry is separated into clear water and dry mud cake by the filter press workshop (plate and frame filter press). The main component of the mud cake is powdery rock, accounting for more than 90%, and it is difficult to utilize the mud cake as a resource due to the addition of chemical agents in the wastewater treatment system. A general power station produces about 1000 tons of mud cake per year. The mud cake, as useless material in the construction site, is very complex to dispose of, must be stored in a designated place, occupies a large amount of land resources, and destroys the local ecological environment, especially in high-altitude areas that are very sensitive to the ecological system, vegetation restoration is very difficult, and the disposal cost is high. Since the mud cake is mostly powdery fine sand, the physical structure is poor, the soil porosity is small, and the plant seeds are very difficult to germinate, and the cohesion is very small. If the construction is carried out on a slope, it is easy to cause slope instability and landslide, resulting in failure of ecological restoration. How to improve the resource utilization rate of useless stone powder in the construction site has become an important problem to be solved in the construction site.

[0003] In addition, the construction of a hydropower station in an alpine and ecologically fragile area causes a certain degree of damage to the slope, which affects the diversity and integrity of the ecological system. In view of the specific ecological restoration challenges in the plateau, such as soil barrenness, uneven precipitation, and large temperature difference, the necessary conditions for plant growth are directly limited. In addition, a large amount of planting soil is needed for the restoration of the ecological system, and the available planting soil resources in the project area are very scarce, which makes it difficult to meet the needs of ecological restoration. Therefore, how to effectively achieve ecological restoration is also a problem that needs to be solved at present. SUMMARY

[0004] One of the purposes of the present application is to provide a soil matrix that can fully utilize the mud cake generated by the sandstone processing system and can provide a platform and carrier for plants, especially slope-growing plants.

[0005] The present application provides a soil matrix, comprising a solid mixture and water, wherein the solid mixture comprises, by mass percentage, 0.005%-0.01% of a growth-promoting nitrogen-fixing composite bacterial agent, 20%-45% of an organic composite slow-release material, 25%-40% of mud cake, 28%-42% of deep soil, 0.05%-0.1% of cationic polyacrylamide, and 0.2%-0.4% of a vinyl acetate-vinyl versatate copolymer.

[0006] The promoting growth and nitrogen fixation composite microbial agent comprises rhizobium, azotobacter chroococcum, bacillus megaterium and azotobacter; and the organic composite slow-release material comprises organic fertilizer, wood powder and fertilizer.

[0007] The present application provides a soil substrate which can make full use of the mud cake generated by the sandstone processing system and provide a platform and carrier for plants, especially for plants growing on slopes.

[0008] The present application uses the promoting growth and nitrogen fixation composite microbial agent and the organic composite slow-release material to fix the nitrogen in the air into nutrients for plants under the symbiotic condition with leguminous plants, and provides energy for plants, and the specific components, cationic polyacrylamide and vinyl acetate-vinyl versatate copolymer, can make the soil substrate have ideal water storage and anti-erosion capacity, and provide a platform and carrier for plants growing on slopes.

[0009] The specific components in the present application can effectively cooperate, and the promoting growth and nitrogen fixation composite microbial agent is composed of rhizobium, azotobacter chroococcum, bacillus megaterium and azotobacter, which can improve the soil enzyme activity, convert the nitrogen in the air into soil nutrients, and improve the soil nutrient structure through the interaction of symbiotic nitrogen fixation bacteria, autotrophic nitrogen fixation bacteria and leguminous plants; the organic composite slow-release material is composed of fermented organic fertilizer, organic matter and compound fertilizer, and the fertilizer effect time of the compound fertilizer is generally about 3 months, the fertilizer effect time of the organic fertilizer is generally about 6 months, and the fermentation time of the organic matter is about 1 year, which can provide nutrients for plants in a short, medium and long term, and in combination with the nitrogen fixation capacity of the promoting growth and nitrogen fixation bacteria and the leguminous plants, nutrients can be continuously provided for plants to meet the growth needs of plants; the soil structure of deep soil and mud cake is heavy, the porosity is small, and the physical structure is poor, and the plant seeds are difficult to germinate and grow in the two components alone, the added polyacrylamide has a linear chain structure with positive electricity, which can tightly adsorb the negative electricity in the deep soil, mud cake and organic fertilizer, and the polyacrylamide solution has certain cohesiveness, which can bond the wood powder together to form a specific three-dimensional multiple net-like structure, which can promote the agglomeration of large aggregates to form large pore channels, and make the colloid molecules between the mud cake and the deep soil form certain small pore channels, and the self-grown super strong water absorption of the polyacrylamide can ensure the stability of the soil structure while making it have water storage and porosity, so as to be suitable for the growth of plants; the vinyl acetate-vinyl versatate copolymer has strong water solubility, the molecules of which can be uniformly distributed on the soil structure to a certain extent to slow down the volatilization of water molecules in the soil substrate of the present application, so that the soil structure has strong water retention capacity.

[0010] The soil matrix of the application comprises, in terms of mass fraction 100%, 35% rhizobium, 35% azotobacter chroococcum, 15% bacillus megaterium and 15% azotobacter.

[0011] The soil matrix of the application comprises, in terms of mass fraction 100%, 25% organic fertilizer, 70% wood powder and 5% fertilizer.

[0012] The organic fertilizer is made of dried fermented cow dung, the particle size of the wood powder is less than 3 cm, and the ratio of N, P2O5 and K2O in the fertilizer is 10:20:20, and the total nutrient content is not less than 50%.

[0013] The soil matrix of the application comprises cationic polyacrylamide with a molecular weight of 8-12 million Da.

[0014] The soil matrix of the application comprises deep soil with a particle size of less than 3 cm, a pH of 5.5-8.5 and a salt content of less than or equal to 0.1%.

[0015] The soil matrix of the application comprises mud cake, and the proportion of powdery rock in the mud cake is more than 90%, and the particle size of the mud cake is less than 3 cm.

[0016] The soil matrix of the application comprises mud cake produced by a sandstone processing system; preferably, the preparation method comprises: treating sandstone aggregate by a sandstone processing system to obtain wastewater; recovering and treating the wastewater to obtain concentrated mud slurry; separating water from the concentrated mud slurry to obtain mud cake.

[0017] As a specific embodiment, the specific preparation method of the mud cake is as follows: when the sandstone processing system processes sandstone into a target particle size, sandstone processing system wastewater (aggregate flushing wastewater) is generated, which is collected by a pipeline and flows to a fine sand recovery workshop, fine sand with a particle size greater than 0.16 mm and stone powder are recovered by a fine sand recovery device to reduce the concentration of the wastewater, and then the wastewater flows to an auxiliary flow sedimentation tank after being dosed by a dosing workshop, and after sedimentation, the water and the concentrated mud slurry are separated, the mud slurry is pressurized by a slurry pump to a filter pressing workshop, and the mud slurry is separated into water and cement-containing mud cake by a plate and frame filter press in the filter pressing workshop, and the cement-containing mud cake falls to the first layer of the filter pressing workshop and is dried and stored, wherein the wastewater system is dosed with PAC (a flocculant inorganic polyaluminum chloride), and the moisture content of the cement-containing mud cake before drying is about 22%. The main component of the dried mud cake is powdery rock, which accounts for more than 90% (and may also contain chemical agents added in the wastewater treatment system).

[0018] Preferably, the sand and stone aggregate is obtained from the tunnel excavation of the hydropower station.

[0019] The organic fertilizer and wood powder can be directly purchased in the area where the project is implemented.

[0020] In the present application, the deep soil refers to the soil below 100 cm from the ground surface, which is less affected by the ground climate and is relatively compact, and contains very few weed seeds, and can be directly collected in the area where the project is implemented.

[0021] In the present application, the soil matrix is in a water-saturated state.

[0022] In the present application, the amount of water included in the soil matrix is preferably in a water-saturated state. The amount of water can be determined by those skilled in the art according to common knowledge in the art.

[0023] Water-saturated refers to the water content in the soil matrix being the maximum water holding capacity, which is the water content when the pores of the soil matrix are completely filled with water under natural conditions (i.e. the maximum amount of water that can be absorbed by the soil matrix, and water will flow out of the soil matrix when added).

[0024] The present application also provides a method for preparing the above-mentioned soil matrix, which comprises:

[0025] The mud cake, deep soil, vinyl acetate-vinyl versatate copolymer and organic composite slow-release material are thoroughly mixed and uniformly mixed to form a mixture A;

[0026] The cationic polyacrylamide is thoroughly dissolved in water to form a solution B;

[0027] The growth-promoting and nitrogen-fixing composite microbial agent is mixed with water to form a solution C;

[0028] The solution B is slowly stirred and mixed with the mixture A until the flowable state slowly changes to a solid state, and the stirring is stopped to obtain a premix one; the premix one is thoroughly absorbed with the solution C to prepare a premix two; water is slowly added to the premix two until the maximum water holding capacity is reached to prepare the soil matrix.

[0029] In the method of the present application, the concentration of cationic polyacrylamide in the solution B is 1.9-2.1 ‰;

[0030] And / or, the solid-liquid ratio of the growth-promoting and nitrogen-fixing composite microbial agent to water in the solution C is 1g:500ml.

[0031] The present application also provides the application of the above-mentioned soil matrix in ecological restoration.

[0032] The present application has at least the following beneficial effects:

[0033] The present application utilizes the mud cake generated by the sandstone processing system to prepare a soil matrix suitable for application on a slope, provides a new idea for solving the problem of surface soil scarcity in high-cold and ecologically fragile areas, reduces ecological secondary damage and water and soil loss, promotes biodiversity recovery, at the same time, opens up a new way for source utilization of the mud cake generated in the process of power station and other engineering construction, solves the influence of the mud cake on the ecological environment and disposal cost, and exhibits remarkable ecological and economic benefits. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present application will be described in detail below with reference to the embodiments. It should be understood that the following embodiments are given only for the purpose of illustration and are not intended to limit the scope of the present application. Those skilled in the art can make various modifications and replacements to the present application without departing from the spirit and principles of the present application.

[0035] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are commercially available or prepared according to conventional methods in the art unless otherwise specified.

[0036] The pro-biotic nitrogen-fixing composite microbial agent in the detailed description part of the present application is purchased from Yangzhou Haicheng Biological Technology Co., Ltd., and the effective viable count is ≥10 billion / g.

[0037] The organic fertilizer is made by drying after fermentation of cow dung (fermentation bacteria are Bacillus stearothermophilus, the moisture content of the substrate is maintained at 50%, the pH value is between 7-8, and the fermentation is fully completed). The particle size of the wood powder is ≤3 cm. The ratio of N, P2O5 and K2O in the fertilizer is 10:20:20, and the total nutrient content is 50%, which is purchased from Changfeng Chemical Co., Ltd.

[0038] The particle size of the mud cake is less than 3 cm, and the rock accounts for 90%.

[0039] The particle size of the deep soil is less than 3 cm, the pH value is 8.3, and the salt content is ≤0.1%.

[0040] The molecular weight of the cationic polyacrylamide is 10 million Da, which is purchased from Aisen (Rudong) Chemical Co., Ltd.

[0041] The vinyl acetate-vinyl versatate copolymer is purchased from Aisen (Rudong) Chemical Co., Ltd.

[0042] Example 1

[0043] The present application provides a method for preparing a slope soil matrix by using mud cake generated by a sandstone processing system, comprising:

[0044] The soil matrix comprises a solid mixture and water, and the solid mixture comprises the following components in the following mass percentages: 0.005% of the growth-promoting and nitrogen-fixing composite microbial agent, 45% of the organic composite slow-release material, 25% of the mud cake, 29.745% of the deep soil, 0.05% of the cationic polyacrylamide, and 0.2% of the vinyl acetate-vinyl versatate copolymer.

[0045] Further, the growth-promoting and nitrogen-fixing composite microbial agent comprises, in terms of the mass fraction 100%, 35% of rhizobium, 35% of azotobacter chroococcum, 15% of bacillus megaterium, and 15% of azospirillum.

[0046] Further, the organic composite slow-release material comprises, in terms of the mass fraction 100%, 25% of organic fertilizer, 70% of wood powder, and 5% of fertilizer.

[0047] The mud cake, the deep soil, the vinyl acetate-vinyl versatate copolymer, and the organic composite slow-release material are fully mixed to obtain a mixture A; the required cationic polyacrylamide is injected into clean water to prepare a 2‰ solution, and the cationic polyacrylamide is fully stirred and dissolved to obtain a solution B; and the required growth-promoting and nitrogen-fixing composite microbial agent is mixed with clean water at room temperature, and the solid-liquid ratio of the growth-promoting and nitrogen-fixing composite microbial agent to the water is 1 g:500 ml to obtain a solution C.

[0048] The solution B is slowly stirred and mixed with the mixture A until the flowable state slowly changes into the solid state, and the stirring is stopped to obtain a premix one; the premix one is fully absorbed with the solution C to prepare a premix two; and water is slowly added to the premix two until the maximum water holding capacity (water saturation state) is reached to prepare the soil matrix.

[0049] Example 2

[0050] The application provides a method for preparing a slope soil matrix by using mud cake generated by a sandstone processing system, comprising the following steps:

[0051] The soil matrix comprises a solid mixture and water, and the solid mixture comprises the following components in the following mass percentages: 0.01% of the growth-promoting and nitrogen-fixing composite microbial agent, 20% of the organic composite slow-release material, 37.49% of the mud cake, 42% of the deep soil, 0.1% of the cationic polyacrylamide, and 0.4% of the vinyl acetate-vinyl versatate copolymer.

[0052] Further, the growth-promoting and nitrogen-fixing composite microbial agent comprises, in terms of the mass fraction 100%, 35% of rhizobium, 35% of azotobacter chroococcum, 15% of bacillus megaterium, and 15% of azospirillum.

[0053] Further, the organic composite slow-release material comprises, in terms of the mass fraction 100%, 25% of organic fertilizer, 70% of wood powder, and 5% of fertilizer.

[0054] Mix the mud cake, deep subsoil, vinyl acetate-vinyl acetate-tert-carbonate copolymer, and organic composite slow-applied material thoroughly to prepare mixture A; inject the required cationic polyacrylamide into clean water to prepare a 2‰ solution, and stir thoroughly until the polyacrylamide is completely dissolved to prepare solution B; mix the required nitrogen-fixing compound bacterial agent with room temperature clean water, with a solid-liquid ratio of 1g:500ml, to prepare solution C.

[0055] Solution B and mixture A are slowly stirred and mixed until the fluid state gradually changes to a solid state. Stirring is then stopped to obtain premix one. Premix one is used to fully absorb solution C to prepare premix two. Water is slowly added to premix two until the maximum water holding capacity (water saturation state) is reached to prepare soil matrix.

[0056] Example 3

[0057] This invention provides a method for preparing slope soil matrix using mud cake produced by a sand and gravel processing system, comprising:

[0058] The soil matrix consists of a solid mixture and water. The solid mixture comprises the following components by mass percentage: nitrogen-fixing compound microbial agent (0.0075%), organic compound slow-release material (24.6175%), mud cake (40%), subsoil (35%), cationic polyacrylamide (0.075%), and vinyl acetate-vinyl tert-carbonate copolymer (0.3%).

[0059] Furthermore, the nitrogen-fixing compound bacterial agent, calculated by mass fraction of 100%, includes: 35% Rhizobium, 35% Azotobacter chrysophyte, 15% Bacillus megaterium, and 15% Azospirillum.

[0060] Furthermore, the organic composite slow-release material comprises, by mass fraction (100%): 25% organic fertilizer, 70% wood flour, and 5% fertilizer.

[0061] Mix the mud cake, deep subsoil, vinyl acetate-vinyl acetate-tert-carbonate copolymer, and organic composite slow-applied material thoroughly to prepare mixture A; inject the required cationic polyacrylamide into clean water to prepare a 2‰ solution, and stir thoroughly until the polyacrylamide is completely dissolved to prepare solution B; mix the required nitrogen-fixing compound bacterial agent with room temperature clean water, with a solid-liquid ratio of 1g:500ml, to prepare solution C.

[0062] Solution B and mixture A are slowly stirred and mixed until the fluid state gradually changes to a solid state. Stirring is then stopped to obtain premix one. Premix one is used to fully absorb solution C to prepare premix two. Water is slowly added to premix two until the maximum water holding capacity (water saturation state) is reached to prepare soil matrix.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing slope soil matrix using mud cakes produced by a sand and gravel processing system. The composition and preparation steps are basically the same as those in Example 1, except that the nitrogen-fixing compound bacterial agent is replaced with an equal mass of microbial agent 1 (the main component is compound polymyxa Bacillus, with a live bacteria count of 20 billion / g, purchased from Shandong Xinfuwo Bioengineering Co., Ltd.).

[0065] Comparative Example 2

[0066] This comparative example provides a method for preparing slope soil matrix using mud cakes produced by a sand and gravel processing system. The composition and preparation steps are basically the same as those in Example 1, except that the nitrogen-fixing compound bacterial agent is replaced with an equal mass of compound microbial agent 2 (the main components are Bacillus and Actinomycetes, with a live bacteria count of 9.8 billion / g, purchased from Beihai Qiangxing Biotechnology Co., Ltd.).

[0067] Comparative Example 3

[0068] This comparative example provides a method for preparing slope soil matrix using mud cakes produced by a sand and gravel processing system. The composition and preparation steps are basically the same as in Example 1, except that the organic compound slow-release material is replaced with an equal mass of compound fertilizer (nitrogen, phosphorus and potassium in a ratio of 15:15:15, with a total nutrient content of not less than 45%, purchased from Stanley Agriculture Group Co., Ltd.).

[0069] Comparative Example 4

[0070] This comparative example provides a method for preparing slope soil matrix using mud cake generated by a sand and gravel processing system. Its components and preparation steps are basically the same as those in Example 1, except that the vinyl acetate-vinyl tert-carbonate copolymer is replaced with an equal mass of water-retaining agent (the main component is superabsorbent polymer, with an effective component of >99%, purchased from Henan Qiantelu Chemical Products Co., Ltd.).

[0071] Comparative Example 5

[0072] This comparative example provides a method for preparing slope soil matrix using mud cakes generated by a sand and gravel processing system. The composition and preparation steps are basically the same as those in Example 1, except that cationic polyacrylamide is replaced with an equal mass of binder 1 (the main components are polyacrylate and polyacrylamide copolymer, with an effective component content of over 95%, purchased from Beijing Jinyuanyi Ecological Environment Industry Co., Ltd.).

[0073] Comparative Example 6

[0074] This comparative example provides a method for preparing slope soil matrix using mud cake generated by a sand and gravel processing system. Its components and preparation steps are basically the same as those in Example 1, except that cationic polyacrylamide is replaced with an equal mass of polyaluminum chloride (the main chemical component is aluminum oxide, the effective substance content is 28%, and it is purchased from Henan Jinyuan Water Treatment Materials Co., Ltd.).

[0075] Comparative Example 7

[0076] This comparative example provides a method for preparing slope soil matrix using mud cakes generated by a sand and gravel processing system. Its components and preparation steps are basically the same as those in Example 1, except that the amount of cationic polyacrylamide is changed from 0.05% to 0.3%, and the amount of deep subsoil is changed from 29.745% to 29.495%.

[0077] Comparative Example 8

[0078] This comparative example provides a method for preparing slope soil matrix using mud cake generated by a sand and gravel processing system. Its composition and preparation steps are basically the same as those in Example 1, except that the amount of vinyl acetate-vinyl tert-carbonate copolymer is changed from 0.2% to 0.6%, and the amount of deep subsoil is changed from 29.745% to 29.345%.

[0079] Experimental Example 1

[0080] This experiment tested the soil matrices prepared in Examples 1-3 and Comparative Examples 1-8. The experimental results are shown in Table 1. Specifically:

[0081] The test method for porosity is as follows: refer to LY / T1215-1999.

[0082] The test method for bulk density is as follows: refer to NY / T1121.4-2006.

[0083] The test method for water holding capacity is as follows: refer to NY / T1121.22-2010.

[0084] The test method for cohesion is as follows: refer to GB / T50123-1999.

[0085] The test method for the internal friction angle is as follows: refer to GB / T50123-1999.

[0086] The germination rate test method is as follows: 100 seeds of Indigofera multiflora are evenly placed in petri dishes containing 5 cm of soil substrate. The petri dishes are placed in a seed germination box, maintaining a certain humidity and setting the temperature to 25℃. After 14 days, the germination rate of the seeds is counted according to the requirements of GB7908 "Grading of Forest Tree Seeds".

[0087] The method for testing growth height is as follows: seedlings that germinated from each soil substrate obtained in the germination rate experiment were planted and their growth height was recorded after 180 days.

[0088] Table 1 Soil structure and plant growth status of each experimental group

[0089]

[0090] The results above show that the soil matrix prepared using mud cake provided by this invention has relatively high porosity, which is suitable for plant germination and growth. It also has relatively low bulk density, high cohesion, and a high angle of internal friction, making it more conducive to the soil matrix's adhesion and fixation on the slope. If the soil bulk density is high, the gravity acting on the slope is greater than the soil's shear strength, making it prone to landslides and causing ecological restoration failure. Furthermore, it has a high water holding capacity, storing more water, which is especially beneficial in arid and hot valley regions where rainfall is low and evaporation is high, thus saving on maintenance costs.

[0091] As can be seen from the examples and comparative examples 7-8, if the amount of cationic polypropylene is too large, it carries too much charge. Even after flocculation and precipitation of colloidal molecules, there is still a large amount remaining, which greatly increases the adhesion, resulting in a deterioration of the physical structure of the soil matrix, a decrease in porosity, an increase in bulk density, difficulty in plant germination, a decrease in growth potential, and a serious impact on the growth height of plants.

[0092] If there is too much vinyl acetate-vinyl tert-carbonate copolymer, it is easy to form a physical film on the surface of the soil matrix, which hinders the exchange of soil matrix with the outside air and water, resulting in very low oxygen content in the soil matrix. When watering or raining, it is difficult for water to enter the soil, which seriously affects the germination rate and growth status of plants.

[0093] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention are protected by the present invention.

Claims

1. A soil substrate, characterized in that, The soil matrix comprises a solid mixture and water, and the solid mixture comprises, by mass percentage, 0.005%-0.01% of a complex nitrogen-fixing bacteria agent, 20%-45% of an organic complex slow-release material, 25%-40% of mud cake, 28%-42% of deep soil, 0.05%-0.1% of cationic polyacrylamide, and 0.2%-0.4% of vinyl acetate-vinyl versatate copolymer; The complex nitrogen-fixing bacteria agent comprises rhizobium, azotobacter chroococcum, bacillus megaterium, and azotobacter; The complex nitrogen-fixing bacteria agent comprises, by mass percentage of 100%, 35% of rhizobium, 35% of azotobacter chroococcum, 15% of bacillus megaterium, and 15% of azotobacter; The effective viable count of the complex nitrogen-fixing bacteria agent is greater than or equal to 10 billion / g. The organic complex slow-release material comprises, by mass percentage of 100%, 25% of organic fertilizer, 70% of wood powder, and 5% of fertilizer; The organic fertilizer is made of dried cow dung after fermentation, the particle size of the wood powder is less than or equal to 3 cm, and the proportion of N, P2O5, and K2O in the fertilizer is 10:20:20, and the total nutrient content is not less than 50%.

2. The soil substrate of claim 1, wherein, The molecular weight of the cationic polyacrylamide is 8-12 million Da. The particle size of the deep soil is less than 3 cm, and the pH is 5.5-8.

5.

3. The soil substrate according to any one of claims 1-2, wherein, The proportion of powdery rock in the mud cake is more than 90%, and the particle size of the mud cake is less than 3 cm.

4. The soil substrate of claim 3, wherein, The mud cake is generated by a sandstone processing system.

5. The soil substrate of claim 4, wherein, The preparation method of the mud cake comprises the following steps: obtaining wastewater by processing sandstone aggregate through a sandstone processing system; obtaining concentrated mud slurry by recycling and processing the wastewater; separating water in the concentrated mud slurry to obtain solid matter; and drying the solid matter to obtain the mud cake.

6. The soil substrate according to any one of claims 1-2, 4-5, wherein, The soil matrix is in a water-saturated state.

7. The soil substrate of claim 3, wherein, The soil matrix is in a water-saturated state.

8. A method of preparing the soil substrate according to any one of claims 1 to 7, characterized in that, The soil matrix comprises: The mud cake, deep soil, vinyl acetate-vinyl versatate copolymer, and organic complex slow-release material are fully mixed to obtain a mixture A; The cationic polyacrylamide is fully dissolved in water to obtain a solution B; The complex nitrogen-fixing bacteria agent is mixed with water to obtain a solution C; The solution B and the mixture A are slowly stirred and mixed until the flowable state slowly changes into a solid state, and the stirring is stopped to obtain a premix one; the premix one fully absorbs the solution C to obtain a premix two; and water is slowly added to the premix two until the maximum water holding capacity is reached to obtain the soil matrix.

9. The method of claim 8, wherein, The concentration of the cationic polyacrylamide in the solution B is 1.9-2.1 ‰; The solid-liquid ratio of the complex nitrogen-fixing bacteria agent to water in the solution C is 1 g:500 ml.

10. The soil matrix according to any one of claims 1-7 is applied to ecological restoration.

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