Coal gangue-based soil matrix as well as preparation method and application thereof

Abstract

The invention provides a coal gangue-based soil matrix as well as a preparation method and application thereof, and belongs to the technical field of ecological restoration. According to the invention, the coal gangue with continuous gradation is adopted, so that the coal gangue-based soil matrix has the particle size distribution of natural soil; urea is added to adjust the carbon-nitrogen ratio of the coal gangue and the biomass waste, and a microbial agent is added for pre-curing, so that the microbial activity is improved, complete decomposition of organic matters is promoted, and formation of water-stable aggregates is promoted; multi-layer root plants are planted together and inoculated with fungi, formation of water-stable aggregates is promoted through root interpenetration and a hypha network, meanwhile, the nutrient circulation efficiency is improved together with root exudates and microbial metabolism, and nutrient release is more balanced. Through multi-dimensional symbiotic regulation and control, the coal gangue-based soil matrix has particle size distribution of natural soil, nutrient balance, high water-stable aggregate content and organic matter content, and is more beneficial to ecological restoration.

Description

Technical Field

[0001] The present invention belongs to the technical field of ecological restoration, and particularly relates to a coal gangue-based soil-like substrate, a preparation method thereof, and an application thereof. Background Art

[0002] As the main solid waste generated during coal mining and washing, long-term open stacking of coal gangue not only occupies a large amount of land resources, but also releases harmful gases and heavy metals due to spontaneous combustion and leaching, resulting in air, water, and soil pollution. In recent years, existing technologies have attempted to improve coal gangue as a soil-like substrate through microbial activation or phytoremediation. However, existing methods are difficult to effectively promote the formation of water-stable aggregates, or the organic matter content of the soil-like substrate is low, or the nutrients are unbalanced, and at the same time, they do not have the particle size distribution characteristics of natural soil, thereby reducing the remediation effect of the coal gangue-based soil-like substrate. Therefore, how to make the particle size distribution of the coal gangue-based soil-like substrate close to that of natural soil, while improving the water-stable aggregates, organic matter content, and nutrient balance of the coal gangue-based soil-like substrate has become a difficult problem in this field. Summary of the Invention

[0003] The purpose of the present invention is to provide a coal gangue-based soil-like substrate, a preparation method thereof, and an application thereof. The coal gangue-based soil-like substrate prepared by the preparation method provided by the present invention has a particle size distribution close to that of natural soil, and at the same time has higher water-stable aggregates, organic matter content, and balanced nutrients.

[0004] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a preparation method of a coal gangue-based soil-like substrate, comprising the following steps:

[0006] (1) Mix coal gangue, biomass waste, urea, and microbial inoculum, and carry out pre-ripening to obtain pre-ripened raw soil; the coal gangue has a continuous gradation, and the mass percentage content of each gradation of the coal gangue is: 20-40% of coal gangue with a particle size of 0-0.05 mm, 20-50% of coal gangue with a particle size of 0.05-1 mm, and 20-40% of coal gangue with a particle size of 1-2 mm;

[0007] (2) Plant plants on the pre-ripened raw soil obtained in step (1), and inoculate fungi for activation to obtain a coal gangue-based soil-like substrate; the plants include plants with a root depth <50 cm, plants with a root depth of 50-90 cm, and plants with a root depth >90 cm.

[0008] Preferably, the mass ratio of coal gangue, biomass waste, and microbial inoculum in step (1) is (89-96):(3-10):(0.003-0.1).

[0009] Preferably, the C / N ratio after mixing coal gangue, biomass waste and urea in step (1) is 18 - 30.

[0010] Preferably, the pre-curing time in step (1) is 7 - 30 d.

[0011] Preferably, the plants with root depth < 50 cm in step (2) include one or more of ryegrass, clover and bermudagrass; the plants with root depth 50 - 90 cm include one or more of alfalfa, rape and vetch; the plants with root depth > 90 cm include one or two of corn and sorghum.

[0012] Preferably, the seeding rate of the plants with root depth < 50 cm in step (2) is 50 - 70 g / m 2 ; the seeding rate of the plants with root depth 50 - 90 cm is 20 - 25 g / m 2 ; the seeding rate of the plants with root depth > 90 cm is 10 - 15 g / m 2 .

[0013] Preferably, the fungus in step (2) is arbuscular mycorrhizal fungi; the inoculation amount of the fungus is 20 - 50 g / m 2 .

[0014] Preferably, the activation time in step (2) is 180 - 360 d.

[0015] The present invention also provides a coal gangue-based soil-like substrate prepared by the preparation method described in the above technical solution. The conductivity of the coal gangue-based soil-like substrate is ≤ 1000 uS / cm, the pH value is 6 - 8, the field water holding capacity is ≥ 20%, the volume ratio of water-stable aggregates with particle size 0.25 - 2 mm is ≥ 20%, the organic matter is 10 - 20 g / kg, the available nitrogen is 50 - 150 mg / kg, the available phosphorus is 10 - 50 mg / kg, the available potassium is 50 - 200 mg / kg, and the cation exchange capacity is 5 - 30 cmol(+) / kg.

[0016] The present invention also provides the application of the coal gangue-based soil-like substrate described in the above technical solution in ecological restoration.

[0017] The present invention provides a method for preparing a coal gangue-based soil-like matrix, comprising the following steps: (1) Mixing coal gangue, biomass waste, urea and microbial inoculum, and carrying out pre-ripening to obtain pre-ripened raw soil; the coal gangue has a continuous gradation, and the mass percentage content of each gradation of the coal gangue is: 20-40% of coal gangue with a particle size of 0-0.05 mm, 20-50% of coal gangue with a particle size of 0.05-1 mm, and 20-40% of coal gangue with a particle size of 1-2 mm; (2) Planting plants on the pre-ripened raw soil obtained in step (1), and inoculating with fungi for activation to obtain a coal gangue-based soil-like matrix; the plants include plants with a root depth <50 cm, plants with a root depth of 50-90 cm, and plants with a root depth >90 cm. The present invention uses coal gangue with a continuous gradation to make the coal gangue-based soil-like matrix have the particle size distribution of natural soil; adding urea to adjust the carbon-nitrogen ratio of coal gangue and biomass waste and adding microbial inoculum for pre-ripening to improve microbial activity, promote the complete decomposition of organic matter, and promote the formation of water-stable aggregates; co-planting multi-level root plants and inoculating with fungi to promote the formation of water-stable aggregates through root interpenetration and hyphal networks, and at the same time, root exudates and microbial metabolism jointly improve the nutrient cycling efficiency, and the nutrient release is more balanced. Through the multi-dimensional symbiotic regulation of particle gradation of coal gangue, synergistic pre-ripening of biomass waste and microbial inoculum, and multi-level root plants-fungi-microorganisms, the coal gangue-based soil-like matrix of the present invention has the particle size distribution of natural soil, nutrient balance, high content of water-stable aggregates and organic matter content, which is more conducive to ecological restoration. Detailed implementation mode

[0018] The present invention provides a method for preparing a coal gangue-based soil-like matrix, comprising the following steps:

[0019] (1) Mixing coal gangue, biomass waste, urea and microbial inoculum, and carrying out pre-ripening to obtain pre-ripened raw soil; the coal gangue has a continuous gradation, and the mass percentage content of each gradation of the coal gangue is: 20-40% of coal gangue with a particle size of 0-0.05 mm, 20-50% of coal gangue with a particle size of 0.05-1 mm, and 20-40% of coal gangue with a particle size of 1-2 mm;

[0020] (2) Planting plants on the pre-ripened raw soil obtained in step (1), and inoculating with fungi for activation to obtain a coal gangue-based soil-like matrix; the plants include plants with a root depth <50 cm, plants with a root depth of 50-90 cm, and plants with a root depth >90 cm.

[0021] Unless otherwise specified, the present invention has no special limitation on the sources of various raw materials, and commercially available products or products from conventional sources well-known to those skilled in the art can be used.

[0022] The present invention mixes gangue, biomass waste, urea, and microbial inoculum, and performs pre-ripening to obtain pre-ripened raw soil.

[0023] In the present invention, the gangue has a continuous gradation, and the mass percentage content of each gradation of the gangue is: 20-40% of gangue with a particle size of 0-0.05 mm, 20-50% of gangue with a particle size of 0.05-1 mm, and 20-40% of gangue with a particle size of 1-2 mm. As an implementation manner, the mass percentage content of each gradation of the gangue may specifically be: 30% of gangue with a particle size of 0-0.05 mm, 50% of gangue with a particle size of 0.05-1 mm, and 20% of gangue with a particle size of 1-2 mm, or 20% of gangue with a particle size of 0-0.05 mm, 50% of gangue with a particle size of 0.05-1 mm, and 30% of gangue with a particle size of 1-2 mm, or 20% of gangue with a particle size of 0-0.05 mm, 40% of gangue with a particle size of 0.05-1 mm, and 40% of gangue with a particle size of 1-2 mm. The present invention uses gangue with a continuous gradation and controls the proportion of each gradation, so that the obtained gangue-based soil matrix has the particle size distribution of natural soil.

[0024] In the present invention, the biomass waste preferably includes one or both of livestock waste and straw; the livestock waste preferably includes one or more of chicken manure, cow dung, and pig manure. The present invention has no special limitation on the type of the straw, and any straw well-known to those skilled in the art can be used.

[0025] In the present invention, the particle size of the biomass waste is preferably ≤2 mm. When the particle size of the biomass waste is not within the above range, the present invention preferably crushes the biomass waste. The present invention has no special limitation on the crushing operation, and any crushing technical solution well-known to those skilled in the art can be used to ensure that the particle size of the crushed biomass waste is within the above range.

[0026] In the present invention, the microbial inoculum preferably includes one or both of actinomycetes or Bacillus subtilis. The present invention adds the microbial inoculum to promote the decomposition of organic matter and the formation of water-stable aggregates.

[0027] In the present invention, the viable count of the microbial inoculum is preferably ≥10 8 CFU / g.

[0028] In the present invention, the mass ratio of the coal gangue, biomass waste, and microbial inoculant is preferably (89 - 96):(3 - 10):(0.003 - 0.1). As an embodiment, the mass ratio of the coal gangue, biomass waste, and microbial inoculant can specifically be 94.9:5:0.1, 90:(3 - 10):(0.003 - 0.1), 91:(3 - 10):(0.003 - 0.1), 92:(3 - 10):(0.003 - 0.1), 93:(3 - 10):(0.003 - 0.1), 94:(3 - 10):(0.003 - 0.1), or 95:(3 - 10):(0.003 - 0.1). By controlling the mass ratio of the coal gangue, biomass waste, and microbial inoculant within the above range in the present invention, the water-stable aggregates and organic matter content of the coal gangue-based soil matrix can be further improved.

[0029] In the present invention, the carbon-nitrogen ratio (mass ratio) after mixing the coal gangue, biomass waste, and urea is preferably 18 - 30. As an embodiment, the carbon-nitrogen ratio after mixing the coal gangue, biomass waste, and urea can specifically be 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. Adding urea to adjust the carbon-nitrogen ratio in the present invention can avoid nutrient imbalance caused by nitrogen deficiency, reduce microbial activity, and incomplete decomposition of organic matter, thereby making the nutrients of the obtained coal gangue-based soil matrix balanced and increasing the organic matter content. By controlling the carbon-nitrogen ratio after mixing the coal gangue, biomass waste, and urea within the above range in the present invention, the nutrient balance and organic matter content of the coal gangue-based soil matrix can be further improved.

[0030] In the present invention, the mixing of the coal gangue, biomass waste, urea, and microbial inoculant is preferably as follows: mix the coal gangue and biomass waste, then add urea, and then add the microbial inoculant. There is no special limitation on the mixing time in the present invention, and it is only necessary to ensure that each component is mixed evenly.

[0031] In the present invention, it is preferred to spread out the mixture after mixing the coal gangue, biomass waste, urea, and microbial inoculant to form a pile, and then carry out pre-ripening.

[0032] In the present invention, the thickness of the pile is preferably ≤0.5 m. By controlling the thickness of the pile within the above range in the present invention, it is more conducive to the progress of the pre-ripening process.

[0033] In the present invention, the pre-ripening is preferably carried out in a ventilated environment at 15 - 30 °C.

[0034] In the present invention, the pre-ripening time is preferably 7 to 30 days. As an implementation method, the pre-ripening time can specifically be 7 days, 10 days, 15 days, 20 days, 25 days or 30 days. Conducting pre-ripening in the present invention can improve microbial activity, promote the decomposition of organic matter, increase the organic matter content of the coal gangue-based soil substrate, while improving the nutrient release efficiency, increasing the nutrient content in the coal gangue-based soil substrate, and at the same time reducing salt accumulation and the electrical conductivity of the coal gangue-based soil substrate. Controlling the pre-ripening time within the above range in the present invention can further increase the nutrient and organic matter content of the coal gangue-based soil substrate and reduce its electrical conductivity.

[0035] In the present invention, it is preferably to turn the pile once every 3 to 5 days during the pre-ripening process. There are no special limitations on the operation of turning the pile in the present invention, and the technical solutions for turning the pile well-known to those skilled in the art can be adopted.

[0036] In the present invention, during the pre-ripening process, the moisture content of the pile body is preferably 40 to 60 wt%, and the temperature of the pile body is preferably 30 to 50 °C.

[0037] After obtaining the pre-ripened raw soil, in the present invention, plants are planted on the pre-ripened raw soil and fungi are inoculated for activation to obtain the coal gangue-based soil substrate.

[0038] The present invention preferably fills the pre-ripened raw soil into a deep pit with a depth of 0.8 to 1.2 m; a drip irrigation system is preferably arranged in the deep pit. In the present invention, after planting the plants, it is preferably to water once in the morning and once in the evening every day, and the single irrigation amount is preferably 1 to 1.5 L / m 2 , and the moisture content of the pre-ripened raw soil is preferably 15 to 25 wt%. The present invention has no special limitations on the specific time for watering once in the morning and once in the evening, and it can be based on the morning and evening times well-known to those skilled in the art. By arranging the drip irrigation system and controlling the irrigation amount in the present invention, the moisture can be controlled, stimulating the plant roots to secrete organic acids and enzymes, and accelerating the dissolution and release of mineral nutrients in the coal gangue.

[0039] In the present invention, the plants include plants with a root depth < 50 cm, plants with a root depth of 50 to 90 cm, and plants with a root depth > 90 cm.

[0040] In the present invention, the plants with a root depth < 50 cm preferably include one or more of ryegrass, clover and bermudagrass; the seeding rate of the plants with a root depth < 50 cm is preferably 50 to 70 g / m 2 (300 to 400 plants / m 2 ); the row spacing of the plants with a root depth < 50 cm is preferably 15 to 18 cm, and the plant spacing is preferably 5 to 6 cm. As an implementation method, the seeding rate of the plants with a root depth < 50 cm can specifically be 50 g / m2 , 55 g / m 2 , 60 g / m 2 , 65 g / m 2 or 70 g / m 2 ; The row spacing of plants with root depth < 50 cm can specifically be 15 cm, 16 cm, 17 cm or 18 cm.

[0041] In the present invention, the plants with root depth of 50 - 90 cm preferably include one or more of alfalfa, rapeseed and vetch; the seeding rate of the plants with root depth of 50 - 90 cm is preferably 20 - 25 g / m 2 (80 - 100 plants / m 2 ); The row spacing of the plants with root depth of 50 - 90 cm is preferably 20 - 25 cm, and the plant spacing is preferably 8 - 10 cm. As an implementation manner, the seeding rate of the plants with root depth of 50 - 90 cm can specifically be 20 g / m 2 , 21 g / m 2 , 22 g / m 2 , 23 g / m 2 , 24 g / m 2 or 25 g / m 2 ; The row spacing of the plants with root depth of 50 - 90 cm can specifically be 20 cm, 21 cm, 22 cm, 23 cm, 24 cm or 25 cm, and the plant spacing can specifically be 8 cm, 9 cm or 10 cm.

[0042] In the present invention, the plants with root depth > 90 cm preferably include one or two of corn and sorghum. In the present invention, the plants with root depth > 90 cm preferably adopt dwarf varieties.

[0043] In the present invention, the seeding rate of the plants with root depth > 90 cm is preferably 10 - 15 g / m 2 ; The row spacing of the plants with root depth > 90 cm is preferably 45 - 50 cm, and the plant spacing is preferably 20 - 25 cm. As an implementation manner, the seeding rate of the plants with root depth > 90 cm can specifically be 10 g / m 2 , 11 g / m 2 , 12 g / m 2 , 13 g / m 2 , 14 g / m 2 or 15 g / m 2; The row spacing of plants with a root depth > 90 cm can specifically be 45 cm, 46 cm, 47 cm, 48 cm, 49 cm, or 50 cm, and the plant spacing can specifically be 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, or 25 cm. In the present invention, three types of plants with different root depths are used. The penetration depth of a single plant's roots is limited, and the hyphal network is single, resulting in poor stability of aggregates, uneven nutrient release, and insufficient diversity of the microbial community. By controlling the seeding rate of plants within the above range and performing high-density mixed planting, the roots can fully penetrate each other, and the hyphal network can be more abundant, further promoting the formation of water-stable aggregates.

[0044] In the present invention, the fungus is preferably arbuscular mycorrhizal fungus; the inoculation amount of the fungus is preferably 20 - 50 g / m 2 . As an embodiment, the inoculation amount of the fungus can specifically be 20 g / m 2 , 25 g / m 2 , 30 g / m 2 , 35 g / m 2 , 40 g / m 2 , 45 g / m 2 or 50 g / m 2 . By inoculating the fungus and controlling its inoculation amount in the present invention, it can act synergistically with plants to further promote the formation of water-stable aggregates.

[0045] In the present invention, it is preferred to start applying full-strength Hoagland nutrient solution 9 - 11 days after planting the plants, watering once a week, and the single watering amount is 1 - 1.5 L / m 2 .

[0046] As an embodiment, the preparation method of the full-strength Hoagland nutrient solution is as follows: Take 1.936 g of Hoagland nutrient solution powder and dissolve it in 1 L of deionized water by heating and boiling until completely dissolved, adjust the pH value to 6.0 - 6.5, and sterilize it at 115 °C under high pressure for 30 min.

[0047] In the present invention, the activation time is preferably 180 - 360 days. As an embodiment, the activation time can specifically be 180 days, 190 days, 200 days, 220 days, 240 days, 260 days, 280 days, 300 days, 320 days, 340 days, or 360 days. During the activation process, the plant roots, fungus, and microbial inoculant act together. In the slow biological small cycle process, through a series of biochemical reactions such as cementation and connection, complexation and precipitation, decomposition and synthesis, oxidation and reduction, etc., the pre-aged raw soil is transformed into a soil-like matrix with stable aggregates, balanced nutrients, and a healthy microbial community structure, similar to natural soil. By controlling the activation time within the above range in the present invention, the various properties of the coal gangue-based soil-like matrix can be further improved.

[0048] After the activation is completed, the present invention preferably removes the planted plants to obtain a coal gangue-based soil matrix. The present invention has no special limitation on the removal operation, and it is only necessary to be able to remove the plants from the coal gangue-based soil matrix.

[0049] The present invention conducts particle size grading on coal gangue, synergistically pre-cures biomass waste and microbial inoculants, and multi-dimensionally symbiotically regulates multi-level root plants-fungi-microorganisms, and controls various parameters, so that the coal gangue-based soil matrix has the particle size distribution, nutrient balance, high water-stable aggregate content and organic matter content of natural soil, which is more conducive to ecological restoration.

[0050] The present invention also provides a coal gangue-based soil matrix prepared by the preparation method described in the above technical solution.

[0051] In the present invention, the properties of the coal gangue-based soil matrix are preferably: conductivity ≤ 1000 uS / cm, pH value is 6-8, field water holding capacity ≥ 20%, the volume ratio of water-stable aggregates with a particle size of 0.25-2 mm ≥ 20%, organic matter 10-20 g / kg, available nitrogen 50-150 mg / kg, available phosphorus 10-50 mg / kg, available potassium 50-200 mg / kg, cation exchange capacity 5-30 cmol(+) / kg.

[0052] The present invention also provides the application of the coal gangue-based soil matrix described in the above technical solution in ecological restoration.

[0053] The present invention has no special limitation on the operation of the application, and the technical solutions of the application well-known to those skilled in the art can be adopted.

[0054] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0055] Example 1

[0056] A preparation method of a coal gangue-based soil matrix is as follows: (1) Mix coal gangue (with continuous gradation, and the mass percentage of each gradation is: 30% of coal gangue with a particle size of 0 - 0.05 mm, 50% of coal gangue with a particle size of 0.05 - 1 mm, and 20% of coal gangue with a particle size of 1 - 2 mm) and biomass waste (chicken manure and straw, and the mass ratio of chicken manure to straw is 2:1, and the particle size of chicken manure and straw is ≤ 2 mm), then add urea (the initial carbon-nitrogen ratio of coal gangue and biomass waste is 15, and the carbon-nitrogen ratio after mixing coal gangue, biomass waste and urea is 28), and then add microbial inoculum (actinomycetes and Bacillus subtilis with a mass ratio of 1:1, and the viable count of the microbial inoculum is 1×10 8 CFU / g), mix evenly, spread out flat (with a thickness of 0.5 m) and carry out pre-maturation for 30 d under ventilation conditions at 25 °C to obtain pre-matured raw soil. During the pre-maturation process, turn the pile once every 4 d, the moisture content of the pile body is 50 wt%, and the temperature of the pile body is 40 °C; the mass ratio of coal gangue, biomass waste and microbial inoculum is 94.9:5:0.1;

[0057] (2) Fill the pre-matured raw soil into a deep pit with a depth of 1.0 m, arrange a drip irrigation system in the deep pit, water once in the morning and once in the evening every day, and the single irrigation amount is 1.2 L / m 2 , then synchronously plant plants with root depths < 50 cm (ryegrass), plants with root depths of 50 - 90 cm (alfalfa), and plants with root depths > 90 cm (corn). The seeding rate of ryegrass is 50 g / m 2 , the row spacing is 16 cm, and the plant spacing is 5.5 cm; the seeding rate of alfalfa is 20 g / m 2 , the row spacing is 22 cm, and the plant spacing is 9 cm; the seeding rate of corn is 10 g / m 2 , the row spacing is 47 cm, and the plant spacing is 22 cm; and inoculate arbuscular mycorrhizal fungi, the inoculation amount is 25 g / m 2 , start applying full-strength Hoagland nutrient solution 10 d after planting, irrigate once a week, and the single irrigation amount is 1.2 L / m 2 , carry out activation for 180 d, pull out the plants to obtain the coal gangue-based soil matrix.

[0058] Example 2

[0059] The difference from Example 1 is that the gradation ratio of coal gangue is different, and other parameters are the same as those in Example 1.

[0060] Example 3

[0061] The difference from Example 1 is that the gradation ratio of coal gangue is different, and other parameters are the same as those in Example 1.

[0062] The gradation of coal gangue, the properties of the prepared coal gangue-based soil matrix and natural soil in Examples 1 - 3 are shown in Table 1.

[0063] Table 1 Properties of the graded coal gangue, coal gangue-based soil-like matrix, and natural soil prepared in Examples 1 to 3

[0064]

[0065] As can be seen from Table 1, the particle size distribution of the coal gangue-based soil-like matrix prepared in the present invention is close to that of natural soil, and it has a higher proportion of water-stable aggregates and organic matter content.

[0066] Comparative Example 1

[0067] On the basis of Example 1, fungi were omitted, and other parameters were the same as those in Example 1.

[0068] Comparative Example 2

[0069] On the basis of Example 1, the planted plants were omitted, and other parameters were the same as those in Example 1.

[0070] The properties of the soil-like matrixes prepared in Comparative Examples 1 to 2 are shown in Table 2.

[0071] Table 2 Properties of the soil-like matrixes prepared in Comparative Examples 1 to 2

[0072]

[0073] As can be seen from Table 2, when only plants are planted or only fungi are inoculated, the content of water-stable aggregates in the soil-like matrix is significantly lower than that in Example 1.

[0074] Comparative Example 3

[0075] On the basis of Example 1, urea was not added, and other parameters were the same as those in Example 1.

[0076] Comparative Example 4

[0077] On the basis of Example 1, the microbial inoculant was not added, and other parameters were the same as those in Example 1.

[0078] The properties of the soil-like matrixes prepared in Comparative Examples 3 to 4 are shown in Table 3.

[0079] Table 3 Properties of the soil-like matrixes prepared in Comparative Examples 3 to 4

[0080]

[0081]

[0082] As can be seen from Table 3, the absence of urea results in nutrient imbalance (N deficiency), reduced microbial activity, incomplete decomposition of organic matter, and decreased water-stable aggregates and organic matter content in the soil-like matrix; the absence of microbial inoculum leads to incomplete decomposition of organic matter and decreased water-stable aggregates and organic matter content in the soil-like matrix.

[0083] Comparative Example 5

[0084] Based on Example 1, pre-curing was omitted, that is, coal gangue, biomass waste, urea, and microbial inoculum were mixed and then plants were grown and fungi were inoculated, and other parameters were the same as in Example 1.

[0085] The properties of the soil-like matrix obtained in Example 1 and Comparative Example 5 are shown in Table 4.

[0086] Table 4 Properties of the soil-like matrix obtained in Example 1 and Comparative Example 5

[0087]

[0088] As can be seen from Table 4, without pre-curing, the organic matter content is low, the microbial activity is insufficient, the nutrient release efficiency is low, and the risk of salt accumulation increases.

[0089] The organic matter decomposition rate in Example 1 reached 89%, while that in Comparative Example 5 was only 54%.

[0090] Comparative Example 6

[0091] Based on Example 1, only ryegrass was planted, and other parameters were the same as in Example 1.

[0092] Comparative Example 7

[0093] Based on Example 1, only alfalfa was planted, and other parameters were the same as in Example 1.

[0094] Comparative Example 8

[0095] Based on Example 1, only corn was planted, and other parameters were the same as in Example 1.

[0096] The properties of the soil-like matrix obtained in Example 1 and Comparative Examples 6-8 are shown in Table 5.

[0097] Table 5 Properties of the soil-like matrix obtained in Example 1 and Comparative Examples 6-8

[0098]

[0099] As can be seen from Table 5, when only one plant is planted, the penetration depth of the single plant root system is limited and the hyphal network is single, resulting in poor aggregate stability, uneven nutrient release, and insufficient microbial community diversity.

[0100] In summary, through the particle size grading of coal gangue, the synergistic pre-ripening of biomass waste and microbial inoculum, and the multi-dimensional symbiotic regulation of multi-level root plants - fungi - microorganisms, the coal gangue-based soil-like substrate has the particle size distribution, nutrient balance, high content of water-stable aggregates and organic matter content of natural soil.

[0101] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a coal gangue-based soil matrix, comprising the following steps: (1) Mix coal gangue, biomass waste, urea and microbial inoculum, and carry out pre-ripening to obtain pre-ripened raw soil; The coal gangue has a continuous gradation, and the mass percentage content of each gradation of the coal gangue is: 20-40% of coal gangue with a particle size of 0-0.05 mm, 20-50% of coal gangue with a particle size of 0.05-1 mm, and 20-40% of coal gangue with a particle size of 1-2 mm; (2) Plant plants on the pre-ripened raw soil obtained in the step (1), and inoculate fungi for activation to obtain a coal gangue-based soil matrix; the plants include plants with a root depth < 50 cm, plants with a root depth of 50-90 cm, and plants with a root depth > 90 cm.

2. The preparation method according to claim 1, wherein In the step (1), the mass ratio of coal gangue, biomass waste and microbial inoculum is (89-96):(3-10):(0.003-0.1).

3. The preparation method according to claim 1, characterized in that, In the step (1), the carbon-nitrogen ratio after mixing coal gangue, biomass waste and urea is 18-30.

4. The preparation method according to claim 1, characterized in that In the step (1), the time of pre-ripening is 7-30 d.

5. The preparation method according to claim 1, characterized in that, In the step (2), the plants with a root depth < 50 cm include one or more of ryegrass, clover and bermudagrass; the plants with a root depth of 50-90 cm include one or more of alfalfa, rapeseed and vetch; the plants with a root depth > 90 cm include one or two of corn and sorghum.

6. The preparation method according to claim 5, wherein In step (2), the seeding rate of plants with a root depth < 50 cm is 50 - 70 g / m 2 ; the seeding rate of plants with a root depth of 50 - 90 cm is 20 - 25 g / m 2 ; the seeding rate of plants with a root depth > 90 cm is 10 - 15 g / m 2 .

7. The preparation method according to claim 1, characterized in that, The fungus in the step (2) is arbuscular mycorrhizal fungus; the inoculation amount of the fungus is 20-50 g / m 2 .

8. The preparation method according to claim 1, characterized in that, In the step (2), the time of activation is 180-360 d.

9. The coal gangue-based soil matrix prepared by the preparation method according to any one of claims 1-8, wherein the conductivity of the coal gangue-based soil matrix ≤ 1000 uS / cm, the pH value is 6-8, the field water holding rate ≥ 20%, the volume ratio of water-stable aggregates with a particle size of 0.25-2 mm ≥ 20%, the organic matter is 10-20 g / kg, the available nitrogen is 50-150 mg / kg, the available phosphorus is 10-50 mg / kg, the available potassium is 50-200 mg / kg, and the cation exchange capacity is 5-30 cmol(+) / kg.

10. Application of the coal gangue-based soil matrix according to claim 9 in ecological restoration.

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