Soil reconstruction method based on sandy mudstone waste slag curing

Abstract

The invention discloses a soil reconstruction method based on sandy mudstone waste slag curing, and belongs to the technical field of slope ecological restoration. The sandy mudstone and the nutrient soil are used as main raw materials of the planting matrix, and the microbial fertilizer and the water-retaining polymer are used as auxiliary materials of the planting matrix; the raw materials and the auxiliary materials are mixed and then applied to the engineering slope, then herbaceous plant seeds are planted in the planting matrix, ecological restoration of the engineering slope is completed, and then soil reconstruction is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of slope ecological restoration, and in particular relates to a soil reconstruction method based on the maturation of sandy mudstone waste. Background Art

[0002] As an important transportation infrastructure, engineering construction plays an important role in promoting and driving the improvement of the transportation system and the development of the economy and society. With the development of the economy and the acceleration of urbanization, large-scale transportation infrastructure construction has never stopped and has always maintained high-speed and high-quality development.

[0003] A large amount of waste slag is generated in engineering construction projects. By 2020, the output of engineering waste slag will reach 3 billion tons, and will continue to grow at a rate of 4.6 billion tons per year. However, the resource utilization rate of waste slag is less than 10%. These slag bodies are relatively loose and broken. Random stacking will aggravate soil erosion and soil loss, and may even become a triggering factor for geological disasters such as collapse, landslides, and mud-rock flows, thereby endangering human health and property. At the same time, waste slag will also occupy land resources, which may not attract immediate attention, but will further aggravate the problem of limited land resources caused by population growth. Therefore, recycling waste slag is a necessary measure to improve the environment.

[0004] During the construction process, different geological layers will be encountered, including sandy mudstone. During the excavation process, this part of the rock is excavated and becomes part of the engineering slag. Sandy mudstone has a pink appearance, and its mineral components are mainly quartz and illite. Its chemical composition is alumina, silicon dioxide, and ferric oxide. It has the characteristics of strong hydrophilicity, weak water permeability, and easy softening. Through proper treatment, such as crushing and screening, sandy mudstone can be separated to achieve "waste into treasure". The resource utilization of sandy mudstone, such as adding soil conditioners, can increase the nutrient content of sandy mudstone, improve its soil structure, and make it a planting matrix that is conducive to plant growth. Using sandy mudstone as a planting matrix for plant growth can reduce the demand for stacking, relieve land pressure, eliminate the safety hazards caused by stacking, and reduce soil erosion. However, the relevant research on how to make resource utilization of sandy mudstone waste needs further exploration. Summary of the invention

[0005] In view of the above technical problems, the present invention proposes a soil reconstruction method based on the maturation of sandy mudstone waste.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A soil reconstruction method based on the maturation of sandy mudstone waste residues comprises the following steps:

[0008] Sandy mudstone is used as the main raw material of the planting matrix, and nutrient soil, microbial fertilizer and water-retaining polymer are used as auxiliary materials of the planting matrix; the raw materials and auxiliary materials are mixed and applied to the engineering slope, and then herbaceous plant seeds are planted in the planting matrix to complete the ecological restoration of the engineering slope.

[0009] First, in the abandoned sandy mudstone, there are a lot of nutrients such as phosphorus and potassium. These nutrients are essential for plant growth. By adding an appropriate amount of microbial fertilizer, the activity of microorganisms can be promoted, and then these nutrients can be decomposed and released, improving soil fertility and providing good conditions for subsequent vegetation growth. Secondly, through the action of microorganisms, some inorganic substances that are difficult to be absorbed and utilized by plants can be converted into forms that can be absorbed and utilized by plants, such as converting difficult-to-decompose organic matter into a form that is easily absorbed by plants, thereby increasing the utilization rate of organic matter in the soil by plants and improving the environment for plant growth. Finally, the addition of water-retaining polymers can help plants retain water in their bodies and avoid plant death due to drought. It can also prevent water loss due to excessive rainfall and ensure the normal growth of plants. In addition, the nutrient soil is rich in various inorganic salts needed by plants, such as nitrogen, phosphorus, potassium, etc., which can meet the nutrient needs of plant growth and enable plants to grow and develop better. After being processed, the organic matter in the nutrient soil is combined with sandy mudstone to improve the physical and chemical properties of the soil, such as increasing the air permeability and water retention of the soil, which is conducive to the growth and development of plant roots. In general, through the treatment of the above-mentioned links, the abandoned sandy mudstone is transformed into a soil suitable for plant growth, and plants can grow normally on this soil, thus realizing the ecological restoration of the engineering slope.

[0010] Furthermore, the mass ratio of the sandy mudstone to the nutrient soil is (7-10): (3-0). That is, without adding nutrient soil, using only sandy mudstone as the main raw material of the planting matrix will also enable the plant to grow well.

[0011] Furthermore, the particle size of the sandy mudstone is ≤5 mm; and / or

[0012] The nutrient soil is composed of fermented straw soil, organic earthworm manure, plant ash and horticultural substrate; wherein the horticultural substrate is composed of vermiculite, pearlite, carbonic acid and root powder.

[0013] Furthermore, based on the total mass of the sandy mudstone and the nutrient soil being 1000 g, the application frequency of the microbial fertilizer is 1-4 times, and the total application amount is 10 g.

[0014] Furthermore, the microbial fertilizer is formed by mixing potassium-solubilizing bacteria, phosphate-solubilizing bacteria and nitrogen-fixing bacteria in a mass ratio of (1-3):1:(1-3).

[0015] Furthermore, the potassium-solubilizing bacteria is Bacillus thuringiensis; and / or

[0016] The phosphate-solubilizing bacteria is Bacillus megaterium; and / or

[0017] The nitrogen-fixing bacteria is Bacillus amyloliquefaciens.

[0018] Furthermore, based on the total mass of the sandy mudstone and the nutrient soil being 1000 g, the application amount of the water-retaining polymer is 80 mL, and the mass concentration of the water-retaining polymer is 0.8-1.0%.

[0019] Furthermore, the herbaceous plant seeds include one or more of Elymus dactylis, Fescue arundinaceus, Lolium perenne and alfalfa.

[0020] Furthermore, the engineering slope is an engineering slope in arid and cold regions.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] The sandy mudstone of the present invention can be used in combination with nutrient soil, microbial fertilizer and water-retaining polymer to effectively improve the physical and chemical properties of the matrix, promote plant growth and enrich the microbial community. The present invention finds that sandy mudstone can be used as a planting matrix for resource utilization. The method provided by the present invention will provide theoretical and technical basis for ecological restoration of mining areas, land reclamation of quarries and vegetation restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 Effects of different planting matrix formulas on soil physical and chemical properties in experimental groups S1-S9 and control groups, including (a) pH; (b) EC; (c) water content; (d) NO3 - -N; (e) NH4 + -N; (f) TN; (g) TP; (h) SOC; (i) effective P; (j) fast-acting K;

[0025] Figure 2 Effects of different planting medium formulas on the growth and development of alfalfa in the experimental groups S1-S9 and the control group, including: (a) chlorophyll content; (b) plant height; (c) root length; (d) average root diameter; (e) root volume; (f) root surface area;

[0026] Figure 3The effects of different planting matrix formulas on soil enzyme activities in the experimental groups S1-S9 and the control group, including (a) S-ALPT; (b) S-CAT; (c) S-AKP; (d) sDHA;

[0027] Figure 4 Effects of different planting matrix formulas on soil microorganisms in experimental groups S1-S9 and control groups, including (a) α-diversity index; (b) AHL&AIP flower distribution map; (c) flower distribution map; (d) heat map at the genus level of different samples;

[0028] Figure 5 It is a flow chart of the present invention. DETAILED DESCRIPTION

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

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

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

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

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

[0034] The present invention aims to study the effects of water-retaining polymers, microbial fertilizers (at different proportions and frequencies) and nutrient soil on sandy mudstone planting substrates and optimize the performance of each component. The present invention uses three types of improvers, taking into account the effects of the following aspects: (1) soil structure, water retention capacity and available nutrients; (2) nutrient conversion capacity and microbial metabolic activity; (3) plant growth; and (4) soil microbial characteristics. The present invention aims to determine the best formula for planting substrates and provide a theoretical basis for the resource utilization of sandy mudstone.

[0035] The following embodiment of the present invention provides a soil reconstruction method based on the maturation of sandy mudstone waste, comprising the following steps:

[0036] Sandy mudstone is used as the main raw material of the planting matrix, and nutrient soil, microbial fertilizer and water-retaining polymer are used as auxiliary materials of the planting matrix; the raw materials and auxiliary materials are mixed and applied to the engineering slope, and then herbaceous plant seeds are planted in the planting matrix to complete the ecological restoration of the engineering slope.

[0037] In some embodiments, the mass ratio of the sandy mudstone to the nutrient soil is (7-10):(3-0). Exemplarily, in the following preferred embodiments of the present invention, the mass ratio of the sandy mudstone to the nutrient soil includes 7:3, 9:1, 10:0 or any range between the aforementioned ratios.

[0038] In the following embodiments of the present invention, the particle size of the sandy mudstone is ≤5 mm.

[0039] In the following embodiments of the present invention, the nutrient soil is composed of fermented straw soil, organic earthworm castings, plant ash and horticultural substrate; wherein the horticultural substrate is composed of vermiculite, pearlite, carbonate and root powder. It can be made by yourself or purchased. The nutrient soil used in the present invention is a purchased product purchased from Kaihong Plastic Industry Co., Ltd., Jurong City.

[0040] In certain embodiments, the total mass of the sandy mudstone and the nutrient soil is 1000g, and the application frequency of the microbial fertilizer is 1-4 times, and the total addition amount is 10g. When using the microbial fertilizer for the first time, the mixing method is adopted, and the microbial fertilizer is mixed with the sandy mudstone and the nutrient soil. When using the microbial fertilizer for the second time and each time thereafter, the method of broadcasting is adopted, that is, the microbial fertilizer is spread on the surface of the planting matrix. Exemplary, in the following preferred embodiments of the present invention, the application frequency of the microbial fertilizer is 1 time, 2 times, 4 times or any value between the aforementioned ratios.

[0041] In some embodiments, the microbial fertilizer is a mixture of potassium-solubilizing bacteria, phosphate-solubilizing bacteria and nitrogen-fixing bacteria in a mass ratio of (1-3):1:(1-3). The potassium-solubilizing bacteria is Bacillus thuringiensis; the phosphate-solubilizing bacteria is Bacillus megaterium; and the nitrogen-fixing bacteria is Bacillus amyloliquefaciens. All the strains used are commercially available products purchased from Guangxi Nongbao Bioengineering Co., Ltd. Exemplarily, in the following preferred embodiments of the present invention, the potassium-solubilizing bacteria, phosphate-solubilizing bacteria and nitrogen-fixing bacteria are in a mass ratio of 1:1:1, 3:1:3 or any range between the aforementioned ratios. Whether the microbial fertilizer has been inactivated is also one of the influencing factors. In the following embodiments of the present invention, if the inactivation treatment is not emphasized, it is assumed that the high-pressure inactivation treatment has not been performed.

[0042] In some embodiments, based on the total mass of the sandy mudstone and the nutrient soil being 1000 g, the mass concentration of the water-retaining polymer is 0.8-1.2%, and the application amount is 80 mL. The water-retaining polymer used in the present invention is the product in patent application CN105925271A, and the specific preparation method of the water-retaining polymer with a mass concentration of 15% is:

[0043] a. Stir and dissolve sodium carboxymethyl cellulose and water in a mass ratio of 1:20 to obtain a sodium carboxymethyl cellulose solution;

[0044] b. Stirring and dissolving anionic polyacrylamide and water at a mass ratio of 1:100 to obtain anionic polyacrylamide solution;

[0045] c. Stir and dissolve ferrous chloride and water at a mass ratio of 1:50 to obtain a ferrous chloride solution;

[0046] d. At room temperature, sequentially add sodium carboxymethyl cellulose solution, anionic polyacrylamide solution and ferrous chloride solution into water and mix them to obtain a water-retaining polymer.

[0047] If you want to obtain water-retaining polymers with different mass concentrations, you can dilute them by adding ultrapure water. For example, in the following preferred embodiments of the present invention, the mass concentration of the water-retaining polymer can be selected to be 0.8%, 1% or any value between the above ratios.

[0048] In some embodiments, the herbaceous plant seeds include one or more of Elymus dahliae, Tall Fescue, Lolium perenne and Alfalfa. For example, in the following preferred embodiments of the present invention, Alfalfa seeds are selected as an example for experimental discussion.

[0049] In some embodiments, the engineering slope is an engineering slope in arid and cold regions.

[0050] In the embodiment of the present invention, organic earthworm castings are excrement excreted by earthworms after digesting organic matter such as garbage and straw and mixing with soil. Earthworm castings are a black, uniform, finely divided substance with a natural earthy smell, with good porosity, aeration, drainage and high water holding capacity. The tiny particles can also help to increase the contact between soil and air as much as possible, because they make the soil no longer compacted and hard after mixing with the soil. Earthworm castings have a large surface area, allowing many beneficial microorganisms to survive, and have the ability to absorb and retain nutrients. Earthworm castings are rich in bacteria, actinomycetes and fungi, which not only mineralize complex substances into effective substances that are easily absorbed by plants, but also synthesize a series of biologically active substances, such as sugars, amino acids, vitamins, etc. The production of these substances gives earthworm castings many special properties. Earthworm castings are a good decomposed organic fertilizer, and also a soil with a granular structure, which has a good promoting effect on plant growth and development. The main components of earthworm castings are: total nitrogen 0.95-2.5%; total phosphorus 1.1-2.9%; total potassium 0.96-2.2%; organic matter 25-38%; humus 21-40%; beneficial bacteria 20 million / g-200 million / g; pH value 6.8-7.1.

[0051] In the embodiment of the present invention, plant ash is ash powder obtained by burning plant straw. The type of plant straw is not limited in the embodiment of the present invention. For example, corn straw, sorghum straw, wheat straw or weed straw can be used as raw materials for plant ash.

[0052] In the embodiment of the present invention, the root powder is obtained by air-drying and then crushing the roots of leguminous plants, and contains a large amount of nitrogen-fixing bacteria.

[0053] The following examples of the present invention select sandy mudstone from a road construction waste dump in Tibet as raw material. The test results of its physical and chemical properties are as follows:

[0054] pH 10.37 Conductivity (EC) (ms / cm): 0.32;

[0055] Natural moisture content (%): 4.15;

[0056] Available potassium (mg / kg): 59.99;

[0057] Available phosphorus (mg / kg): 0.39;

[0058] Organic carbon (g / kg): 6.29;

[0059] Ammonium nitrogen (mg / kg): 0.25;

[0060] Nitrate nitrogen (mg / kg): 1.02;

[0061] Total nitrogen (g / kg): 0.22;

[0062] Total phosphorus (g / kg): 0.14.

[0063] The technical solution of the present invention is further illustrated by the following embodiments.

[0064] Figure 5 It is a flow chart of the present invention.

[0065] Example 1

[0066] A soil reconstruction method based on the maturation of sandy mudstone waste residues comprises the following steps:

[0067] The experiment was conducted in a greenhouse with an average temperature of 25°C and a humidity of 50% and lasted for 84 days. On January 11, 2024, 30 alfalfa seeds were sown manually in pots with a diameter of 15.5 cm and a height of 10.5 cm. Alfalfa seeds were disinfected with 10% hydrogen peroxide for 10 minutes before sowing and then rinsed with deionized water. In order to ensure the normal growth of the plants, the irrigation water volume was maintained at 80% of the moisture content in the control area (CK), equivalent to 88 grams per irrigation. The plants were not fertilized during the growth period. Each group was divided into 3 parallel groups, with a total of 30 potted plants.

[0068] The planting matrix used during planting was a mixture of sandy mudstone, nutrient soil, microbial fertilizer and water-retaining polymer. The effects of the following four factors on the physical and chemical properties of the soil were mainly investigated: (1) the mass ratio of sandy mudstone to nutrient soil (7:3, 9:1, 10:0; SS, named A1, A2, A3, respectively); (2) the concentration of water-retaining polymer (0.8%, 1%, 0%, WP, named B1, B2, B3, respectively); (3) the ratio and treatment of microbial fertilizer strains (1:1:1, 3:1:3, and 1:1:1 mixed microbial fertilizer after inactivation, MC, named C1, C2, C3, respectively); (4) the frequency of microbial fertilizer application (1 time, 2 times and 4 times, MF named D1, D2, D3, respectively). The specific schemes were set as follows:

[0069] Experimental group S1

[0070] The mass ratio of sandy mudstone to nutrient soil is 7:3, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0071] Ultrapure water was added to the water-retaining polymer with a mass concentration of 15% to obtain a water-retaining polymer with a mass concentration of 0.8%. The added amount was 80 mL.

[0072] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 1:1:1; the application frequency is 1 time, adding 10 g / time;

[0073] Experimental group S2

[0074] The mass ratio of sandy mudstone to nutrient soil is 7:3, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0075] Ultrapure water was added to the water-retaining polymer with a mass concentration of 15% to obtain a water-retaining polymer with a mass concentration of 1.0%. The added amount was 80 mL.

[0076] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 3:1:3; the application frequency is 2 times, 5 g is added each time, and the interval between the first and second times is 7 days;

[0077] Experimental group S3

[0078] The mass ratio of sandy mudstone to nutrient soil is 7:3, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0079] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 1:1:1; the application frequency is 4 times, 2.5 g is added each time, and the interval between each addition is 7 days. The microbial fertilizer is conventionally inactivated by high pressure.

[0080] Experimental group S4

[0081] The mass ratio of sandy mudstone to nutrient soil is 9:1, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0082] Ultrapure water was added to the water-retaining polymer with a mass concentration of 15% to obtain a water-retaining polymer with a mass concentration of 0.8%. The added amount was 80 mL.

[0083] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 3:1:3; the application frequency is 4 times, 2.5 g is added each time, and the interval between each addition is 7 days;

[0084] Experimental group S5

[0085] The mass ratio of sandy mudstone to nutrient soil is 9:1, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0086] Ultrapure water was added to the water-retaining polymer with a mass concentration of 15% to obtain a water-retaining polymer with a mass concentration of 1.0%. The added amount was 80 mL.

[0087] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 1:1:1; the application frequency is 1 time, and 10 g is added each time; the microbial fertilizer is subjected to conventional high-pressure inactivation treatment.

[0088] Experimental group S6

[0089] The mass ratio of sandy mudstone to nutrient soil is 9:1, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0090] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 1:1:1; the application frequency is 2 times, 5g is added each time, and the interval between each addition is 7d.

[0091] Experimental group S7

[0092] The mass ratio of sandy mudstone to nutrient soil is 10:0, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0093] Ultrapure water was added to the water-retaining polymer with a mass concentration of 15% to obtain a water-retaining polymer with a mass concentration of 0.8%. The added amount was 80 mL.

[0094] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 1:1:1; the application frequency is 2 times, 5 g is added each time, and the interval between each addition is 7 days; the microbial fertilizer undergoes conventional high-pressure inactivation treatment.

[0095] Experimental group S8

[0096] The mass ratio of sandy mudstone to nutrient soil is 10:0, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0097] Ultrapure water was added to the water-retaining polymer with a mass concentration of 15% to obtain a water-retaining polymer with a mass concentration of 1.0%. The added amount was 80 mL.

[0098] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 1:1:1; the application frequency is 4 times, 2.5 g is added each time, and the interval between each addition is 7 days;

[0099] Experimental group S9

[0100] The mass ratio of sandy mudstone to nutrient soil is 10:0, and the total amount of sandy mudstone and nutrient soil added is 1000g;

[0101] The microbial fertilizer is a mixture of Bacillus thuringiensis, Bacillus megaterium and Bacillus amyloliquefaciens in a mass ratio of 3:1:3; the application frequency is once, and 10 g is added each time.

[0102] Control group 1 (CK)

[0103] 1000g of sandy mudstone was used as the entire planting medium.

[0104] Table 1 Parameter changes of experimental groups S1-S9

[0105]

[0106]

[0107] 1. Physical and chemical properties of soil

[0108] pH: acidity meter;

[0109] Electrical conductivity (EC): The electrical conductivity of the soil was measured using an acidometer;

[0110] Moisture content: The soil moisture content is measured by the ring knife method;

[0111] Organic carbon: potassium dichromate oxidation-spectrophotometry;

[0112] Nitrate nitrogen (NO3 - -N): hydrazine sulfate reduction method;

[0113] Ammonium nitrogen (NH4 + -N): Sodium salicylate method;

[0114] Available potassium (Available P): ammonium acetate extraction-flame atomic absorption spectrometry;

[0115] Available P: phosphomolybdenum blue method;

[0116] Total nitrogen (TN): sulfuric acid digestion-sodium salicylate method;

[0117] Total phosphorus (TP): sulfuric acid digestion-molybdenum antimony resistance method.

[0118] Figure 1 Effects of different planting matrix formulas on soil physical and chemical properties in experimental groups S1-S9 and control groups, including (a) pH; (b) EC; (c) water content; (d) NO3 - -N; (e) NH4 + -N; (f) TN; (g) TP; (h) SOC; (i) effective P; (j) fast-acting K. Data are expressed as the mean ± standard deviation of three replicates. Different lowercase letters indicate significant differences (p < 0.05), the same below, from Figure 1It can be seen that the values ​​of the experimental groups 1-9 are much higher than those of the control group (P<0.01). Soil pH is often used as a quality standard for mine soil. The results of Figure (a) show that the pH value increases with the increase of sandy mudstone, which may be because the pH value of sandy mudstone itself is alkaline. The pH value of the sandy mudstone used in the present invention is 10.25, so as the sandy mudstone increases, its pH value will increase. In addition, soil moisture content is an important indicator to describe the soil moisture status and reflect the soil composition. Water shortage may lead to matrix disintegration and failure of plant growth. Therefore, the water retention of the planting matrix is ​​also crucial. The soil moisture content in the experimental groups S1-S9 was higher than that in the control group (P<0.05). As shown in Figure (c), with the increase in the amount of sandy mudstone, the decrease in water content may be due to the increase in sandy mudstone, resulting in an increase in soil pore volume. In addition, nutrient soil is rich in organic matter and mineral nutrients and has good water retention capacity. Therefore, when sandy mudstone increases, the overall water retention capacity of the planting matrix decreases, resulting in a decrease in water content. Soil electrical conductivity (EC) can be used as an indicator of soil property changes. A low EC value indicates that the concentration of soluble ions in the soil is low, the nutrient content that can be absorbed by crops is low, and the soil fertilizer supply capacity is weak; the higher the EC value, the more it affects the roots and leaves of crops, and the more serious the necrosis of plants. As can be seen from Figure (b), the EC values ​​of each experimental group are higher than those of the control group. When the EC value is high, the impact on salt-tolerant plants is small, so the plant (alfalfa) selected by the present invention has salt tolerance itself and will not be affected by the increase of EC value. The conductivity when the frequency of microbial fertilizer addition is 4 times (P<0.05) is lower than the conductivity when the frequency of microbial fertilizer addition is 1 time and 2 times. This is because after quantitatively adding microbial fertilizers to the soil for multiple times, the microbial activity and the resulting microbial diversity lead to a decrease in conductivity. Moreover, it can be seen from Figures (d), (e), (f), (g), (h), (i), and (j) that the mass ratio (SS) of sandy mudstone and nutrient soil and the concentration (WP) of water-retaining polymer have a greater impact on the physical and chemical properties of the soil, and other factors have a smaller impact on the physical and chemical properties of the soil. For example, after adding 1000g of sandy mudstone to the control group, the chemical properties of the planting matrix (NO3 - -N, TN, TP, effective K, effective P) were improved. This phenomenon occurs because sandy mudstone contains more weathering nutrients than soil, which creates favorable conditions for plant growth. In addition, a water-retaining polymer with a mass concentration of 1% increased NH4 + -N, TN, TN, TP, SOC and available P contents, which may be because water-retaining polymers can provide exogenous organic matter to the soil through mineralization and humification processes, improving soil fertility. With the increase of water-retaining polymer concentration, the nutrients produced by the degradation of water-retaining polymers in the soil also increased significantly.

[0119] 2. Plant germination and growth

[0120] At 84 days after sowing, any one of the three parallel potted plants was selected, numbered, and photographed with a black cloth as a background plate by mobile phone. The alfalfa was then harvested according to the number, and the plants were washed with deionized water, and the root length, root surface area, root volume, and average root diameter were measured using a root scanner.

[0121] Select 5 alfalfa plants from each pot and measure the plant height with a ruler until one decimal point. The chlorophyll content was determined by ethanol extraction. Then incubate in the dark at 25°C until the leaf pigment extraction is complete, remove the supernatant, and pour the above pigment extract into a 1cm colorimetric cup. Determine the absorbance of the supernatant at 470, 649 and 665nm to calculate the chlorophyll content in the leaves.

[0122] Figure 2 The effects of different planting matrix formulas on the growth and development of alfalfa in the experimental groups S1-S9 and the control group, including (a) chlorophyll content; (b) plant height; (c) root length; (d) average root diameter; (e) root volume; (f) root surface area. As shown in Figure (a). The chlorophyll content of each experimental group S1-S9 was higher than that of the CK group. This research result is consistent with the research results of soil physical and chemical properties. The root system results are shown in Figures (bf), and the alfalfa root system has been improved. The improvement of plant growth (plant height, root length, root surface area, root volume, average root diameter) indicates the improvement of the environment and the sufficiency of nutrients required for plant growth. The reason for the analysis is that there are more nutrients (NPK) in sandy mudstone, and increasing the amount of sandy mudstone will increase the nutrients in the planting matrix; the increase of water-retaining polymers is conducive to plant growth; adding microbial fertilizers in batches is conducive to the growth of alfalfa, and because the microbial agent contains a large number of active functional bacteria, it can continuously provide nutrients in the soil, promote the establishment and development of microbial communities, thereby improving soil fertility and air permeability. However, adding excessive amounts of microbial fertilizers at one time will be detrimental to the soil respiration rate, thereby damaging plant growth. Therefore, the present invention adds microbial fertilizers in batches, and it can also be seen from the figure that the growth and development of alfalfa when the frequency of microbial fertilizer addition is 1 is significantly lower than the growth and development of alfalfa when the number of additions is 4.

[0123] 3. Determination of soil enzyme activity

[0124] Soil alkaline phosphatase (S-AKP), soil alkaline proteinase (S-ALPT), soil dehydrogenase (sDHA), and soil catalase (S-CAT) were all determined using enzyme-linked immunosorbent assay kits using a microplate reader.

[0125] Soil enzyme activity reflects the intensity and direction of various biochemical processes in the soil. It is also unified with the environment and is easily affected by physical, chemical and biological factors in the environment. Soil alkaline protease (S-ALPT) is an enzyme that catalyzes protein hydrolysis under alkaline conditions. Its activity can be used as an indicator of soil microbial activity. Figure 3 The effects of different planting matrix formulas on soil enzyme activities in experimental groups S1-S9 and control groups, including (a) S-ALPT; (b) S-CAT; (c) S-AKP; (d) sDHA. . Different lowercase letters indicate significant differences (p<0.05). As shown in Figure (a), the activity of S-ALPT decreased with the increase of the proportion of nutrient soil; the application of WP, MC and MF had a significant effect on S-ALPT (P<0.05), but the difference between different levels was not significant (P<0.05). Catalase (S-CAT) can destroy hydrogen peroxide produced by biochemical reactions in the soil and reduce its harm to plants. S-CAT is negatively correlated with the available phosphorus content. Soil phosphatase is an organic compound that can hydrolyze phosphorus in the soil and release corresponding alcohols and inorganic phosphorus. Its activity directly affects the decomposition and transformation of organic phosphorus in the soil and its biological effectiveness. According to the difference in optimal pH value, phosphatases can be divided into acid phosphatases, neutral phosphatases and alkaline phosphatases. Since the planting substrates used in the present invention are alkaline soil samples with a pH greater than 7, the present invention only measures the activity of alkaline phosphatase (S-AKP). When SS is 7:3, the alkaline phosphatase activity is significantly higher than that when SS is 9:1 and 10:0. As shown in Figure (c), the activity of S-AKP is negatively correlated with the soil pH value. Soil dehydrogenase (s-DHA) can be used as a sensitive marker for soil degradation and soil microbial activity. The effect of SS on dehydrogenase is consistent with the effect of SS on S-AKP.

[0126] 4. Soil microbial characteristics and signal molecule concentrations

[0127] Soil microbial biomass, activity, and diversity are indicators of soil fertility and ecosystem productivity. Good soil quality with diverse, rich microbial communities and high levels of activity is a prerequisite for plant growth. Soil amendments not only improve soil structure, but also, as a source of nutrients, can strongly affect soil microbiota. To analyze the response of microbial communities to SS, WP, MC, and MF, the present invention conducted microbial analysis and determined the diversity index and operational taxonomic units (OTUs) of each treatment. Figure 4The effects of different planting matrix formulas on soil microorganisms in the experimental groups S1-S9 and the control group, including (a) α-diversity index; (b) AHL&AIP flower distribution map; (c) flower distribution map; (d) heat map at the genus level of different samples. As shown in Figure (c), the rarefaction curves of most samples are flat curves, indicating that the OTUs coverage of the samples has reached saturation. In addition, the coverage of Goods is greater than 98%, which can reflect the structure of the soil microbial community. The distribution of OTUs is shown in Figure (b). The number of unique OTUs in each experimental group is significantly greater than that in the control group. The Chao 1 index is significantly positively correlated with the richness of the microbial community, and the Shannon index is positively correlated with the Simpson index.

[0128] The distribution of OTUs in soils with different treatments is shown in the petal plot (see Figure (b)). All samples contained 142 identical OTUs, including 470 in the CK group, and the OTUs in each experimental group were significantly higher than those in the control group. In addition, a heat map was generated at the genus level (see Figure (d)). In the CK group, Pseudomonas, Vibrio, and Bacillus were dominant genera. More Bacillus was detected in S2, S5, S6, S7, and S8, indicating that these environments are suitable for the survival of Bacillus. Bacillus will produce many antimicrobial metabolites such as bacteriocins, enzymes, and lipopeptides, which have inhibitory effects on a variety of pathogenic microorganisms such as Pseudomonas. Since Bacillus was not added to the control group, the antagonism and synergistic effects on other bacteria were weak, which was more conducive to the growth and reproduction of other bacteria. The structure of the microbial community changed after different treatments, indicating that bacteria may adjust their abundance according to different soil environments.

[0129] The present invention studies the concentration of AIP and AHL signal molecules in the soil, see Figure (b). WP, MC and MF have significant effects on AIP and AHL (P<0.05), but the level difference is not statistically significant (P<0.05). AIP and AHL are effector signal molecules that affect biofilm formation and have the function of monitoring microbial population density. Microorganisms can coordinate in a complex environment by controlling the cycle of signal molecule synthesis, thereby improving. The present invention shows that the addition of exogenous substances can change the concentration of signal molecules and promote bacterial quorum sensing to affect the microbial ecological properties of the soil.

[0130] 5. Screening and optimization of substrate ratio

[0131] Correlation analysis of various indicators of alfalfa showed that its physical and chemical properties were significantly correlated with some plant growth indicators. In order to convert various indicators into comprehensive variables for analysis, the present invention used the principal component analysis method to perform weight analysis on the variables, and used the TOPSIS method to obtain the final score of each experimental group. As shown in Table 2.

[0132] Table 2 TOPSIS evaluation calculation results

[0133]

[0134] As can be seen from Table 2, the final scores from high to low are: S8>S2>S4>S7>S1>S9>S6>S3>S5>CK. Therefore, considering that the alfalfa experimental group (S7, S8, S9) grew well, the present invention selected S8 as the final choice and determined the optimal ratio of the planting residue matrix: the mass ratio of sandy mudstone to nutrient soil was 10:0; the mass concentration of water-retaining polymer was 1.0%; the application ratio of microbial fertilizer was: the mass ratio of Bacillus thuringiensis, Bacillus megaterium, Bacillus amyloliquefaciens was 1:1:1; the application frequency of microbial fertilizer was 4 times.

[0135] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A soil reconstruction method based on the maturation of sandy mudstone waste, characterized in that: The following steps are involved: Sandy mudstone is used as the main raw material of the planting matrix, and nutrient soil, microbial fertilizer and water-retaining polymer are used as auxiliary materials of the planting matrix; the raw materials and auxiliary materials are mixed and applied to the engineering slope, and then herbaceous plant seeds are planted in the planting matrix to complete the ecological restoration of the engineering slope.

2. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 1 is characterized in that: The mass ratio of the sandy mudstone to the nutrient soil is (7-10): (3-0).

3. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 2 is characterized in that: The particle size of the sandy mudstone is ≤5 mm; and / or The nutrient soil is composed of fermented straw soil, organic earthworm manure, plant ash and horticultural substrate; wherein the horticultural substrate is composed of vermiculite, pearlite, carbonic acid and root powder.

4. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 1 is characterized in that: Based on the total mass of the sandy mudstone and the nutrient soil being 1000 g, the application frequency of the microbial fertilizer is 1-4 times, and the total application amount is 10 g.

5. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 4 is characterized in that: The microbial fertilizer is prepared by mixing potassium-solubilizing bacteria, phosphate-solubilizing bacteria and nitrogen-fixing bacteria in a mass ratio of (1-3):1:(1-3).

6. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 5 is characterized in that: The potassium-solubilizing bacteria is Bacillus thuringiensis; and / or The phosphate-solubilizing bacteria is Bacillus megaterium; and / or The nitrogen-fixing bacteria is Bacillus amyloliquefaciens.

7. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 1, characterized in that: Based on the total mass of the sandy mudstone and the nutrient soil being 1000 g, the application amount of the water-retaining polymer is 80 mL, and the mass concentration of the water-retaining polymer is 0.8-1.0%.

8. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 1, characterized in that: The herbaceous plant seeds include one or more of Elymus dactylis, tall fescue, ryegrass and alfalfa.

9. The soil reconstruction method based on the maturation of sandy mudstone waste according to claim 1, characterized in that: The engineering slope is an engineering slope in arid and cold areas.

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