Red clay roadbed slope vegetation structure and construction method thereof

Abstract

The present application relates to a kind of red clay roadbed slope planting structure and its construction method, it is related to ecological restoration and roadbed slope protection technical field.The structure includes red clay slope body, the erosion-resistant impermeable planting substrate layer covered on its surface and the ecological landscape layer laid on the substrate layer;Wherein the erosion-resistant impermeable planting substrate layer is composed of fiber skeleton, water-retaining agent, adhesive, nano-modified clay and microencapsulated composite microbial inoculum, and the ecological landscape layer is composed of three-dimensional plant community of deep-rooted arbor, shrub, herb and climbing plant.This application can realize the slope surface erosion resistance, anti-cracking and moderate impermeable engineering protection and rhizosphere growth promotion, biological crust and root-fungus symbiosis ecological soil fixation synergy, effectively improve the long-term stability of red clay slope and vegetation survival rate.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration and roadbed slope protection technology, specifically to a vegetation structure for red clay roadbed slopes and its construction method. Background Technology

[0002] Red clay is widely distributed in the hot and humid regions of southern China. It is characterized by high water content, high plasticity, and easy cracking when dry. It is also highly water-sensitive, with its strength decreasing sharply when exposed to water. Under rainfall conditions, its slopes are prone to engineering problems such as erosion, softening, and landslides. At the same time, red clay soil is nutrient-poor and highly acidic. Its high aluminum and iron content further inhibits plant growth, making it difficult for vegetation to form a stable community and resulting in poor ecological restoration.

[0003] Existing slope ecological protection methods mostly adopt single protection, including hydroseeding, grid + topsoil protection, etc. In red clay environment, they often show problems such as insufficient erosion resistance, coexistence of drying shrinkage cracking and infiltration softening, and difficulty in establishing vegetation, resulting in insufficient coupling between engineering and ecology.

[0004] Therefore, there is an urgent need for a composite vegetation system that combines erosion resistance, crack resistance, and moderate seepage prevention capabilities, while also supporting the continuous growth of plants, to achieve synergy between ecology and engineering. Summary of the Invention

[0005] To address the challenges of weak erosion resistance and ecological restoration in existing red clay slopes, this invention proposes a vegetation structure and construction method for red clay roadbed slopes. The aim is to construct a comprehensive system that ensures slope stability and sustainable healthy vegetation growth through the synergy of a composite erosion-resistant and seepage-proof vegetation matrix layer and an ecological landscape layer.

[0006] To achieve the above-mentioned technical objectives, the present invention is implemented through the following solution:

[0007] The first aspect of this invention provides a vegetation structure for red clay roadbed slopes, comprising:

[0008] This invention proposes a vegetation structure for red clay roadbed slopes, comprising:

[0009] Red clay slope body;

[0010] The corrosion-resistant and seepage-proof vegetated substrate layer, in the form of a thin shell with a thickness of 5-15 mm, covers the surface of the red clay slope. Its raw material composition includes a fiber skeleton, water-retaining agent, binder, nano-modified clay, and composite microbial inoculant; among which,

[0011] The nano-modified clay is used to swell and fill micro-cracks when exposed to water, thereby reducing the pore connectivity of the red clay surface layer.

[0012] The composite microbial agent consists of a functional microbial community comprising 35% nitrogen-fixing bacteria, 25% phosphate-solubilizing bacteria, 25% arbuscular mycorrhizal fungi, and 15% cyanobacteria. This composite microbial agent is encapsulated in microcapsules composed of a porous carrier and an outer encapsulation membrane. It is used to colonize the surface of red clay slopes and form a mycelial network and biocrust that symbiotically supports subsequent plant roots.

[0013] The ecological landscape layer is laid on top of the corrosion-resistant and seepage-proof vegetation substrate layer, which includes a three-dimensional plant community composed of deep-rooted trees, shrubs, herbs and climbing plants.

[0014] Among them, the mycelial network formed by the nano-modified clay and the composite microbial agent, together with the plant root system, work together to form a composite structure that enhances the water stability and stabilizes the soil on the surface of the red clay slope.

[0015] Furthermore, the porous carrier is a mixture of attapulgite soil, biochar, and organic compost, accounting for 1.0-5.0% of the total dry mass of the anti-corrosion and seepage-proof vegetation substrate layer; the outer encapsulation membrane is a double-layer encapsulation structure formed by sodium alginate and chitosan.

[0016] Furthermore, the nitrogen-fixing bacteria are *Azotospira*; the phosphate-solubilizing bacteria are *Bacillus phosphate-solubilizing*; the arbuscular mycorrhizal fungi are *Rhizocarpium irregularis*; and the cyanobacteria are *Nostoc*.

[0017] Furthermore, the nano-modified clay is one or more of the surface-modified nano-montmorillonite, nano-bentonite, or nano-attapulgite, and its dosage is 2.0-5.0% of the total dry mass of the anti-corrosion and seepage-proof vegetation substrate layer; the surface modification is at least one of ion exchange intercalation, silane coupling grafting, and polymer coating; the modifier is selected from one or more of quaternary ammonium salt cationic surfactants, cationic polymers, silane coupling agents, and film-forming polymers; the amount of modifier used in ion exchange intercalation is 0.5-10% of the clay mass; the grafting amount of silane grafting is 0.2-5%; the water contact angle of the modified clay is 40-110°, and it retains the ability to swell and fill microcracks upon contact with water.

[0018] Furthermore, the fiber skeleton comprises alkali-treated plant long fibers and recycled pulp fibers, wherein the plant long fibers are 10-40 mm in length and the recycled pulp fibers are 3-12 mm in length, and the total content of the fiber skeleton is 1.8-5.0% of the total dry mass of the corrosion-resistant and seepage-proof plant substrate layer.

[0019] Furthermore, the water-retaining agent is sodium polyacrylate superabsorbent resin with a particle size of 0.3 to 1.5 mm, and the dosage is 0.3 to 0.75% of the total dry mass of the anti-corrosion and seepage-proof vegetation substrate layer; the adhesive is one or more combinations of lignin sulfonate, modified starch, polyvinyl alcohol and natural latex, and the total dosage is 1.0 to 5.0%.

[0020] Furthermore, the ecological landscape layer also includes a biodegradable liquid mulch film covering agent, which is sprayed onto the surface of the substrate layer to form an initial biodegradable protective film. Its components include: 10-40% natural lignin, 10-30% water-based natural latex, 1-5% plant-based dyes, 5-15% plant gum, and the remainder is water and additives. The spraying amount is 0.15-0.35 kg / m², wherein the additive is borax, which accounts for 0.15-0.25% of the total mass of the biodegradable liquid mulch film covering agent.

[0021] Another aspect of the present invention discloses a construction method for the vegetation structure on the red clay roadbed slope, comprising the following steps:

[0022] Step 1: Slope preparation: Level the surface of the red clay slope.

[0023] Step 2: Preparation of corrosion-resistant and seepage-proof vegetated substrate mixture: Mix fiber skeleton, water-retaining agent, binder and nano-modified clay, and add microcapsules containing composite microbial agents before spraying to obtain dry mixture;

[0024] Step 3, spray molding: Using a dry spraying process, the dry mixture is sprayed onto the surface of the red clay slope to form a corrosion-resistant and seepage-proof vegetation matrix layer with a thickness of 5-15 mm.

[0025] Step 4, Water Mist Curing: After spraying, continue fine mist watering for 5-10 days;

[0026] Step 5: Ecological landscape construction: After maintenance is completed, sow and plant three-dimensional plant communities, and spray biodegradable liquid mulch to form an initial protective film.

[0027] Furthermore, the method for preparing the microcapsules encapsulated with the composite microbial agent includes: adsorbing the composite microbial agent onto a porous carrier to obtain a microbial-porous carrier mixture; dispersing the microbial-porous carrier mixture in an aqueous sodium alginate solution, and then adding it dropwise into a calcium chloride solution for cross-linking and solidification to form a gel core; and immersing the gel core in a chitosan solution for coating to form a microcapsule.

[0028] Furthermore, in step two, the microcapsules containing the composite microbial agent are added last before spraying to avoid prolonged contact with alkaline materials.

[0029] The red clay roadbed slope vegetation structure of this invention can simultaneously achieve erosion resistance, crack resistance, and moderate seepage prevention, while improving vegetation establishment. The specific synergistic mechanism of the system is as follows:

[0030] (1) Synergistic effect of water retention and seepage prevention

[0031] The nano-modified clay forms a micro-filling and structural modification effect within the erosion-resistant and seepage-proof vegetation matrix layer, reducing the pore connectivity of the red clay surface and inhibiting the effective infiltration of rainwater and the formation of micro-migration channels, thereby achieving "moderate seepage prevention" and anti-dispersion. Simultaneously, the water-retaining agent absorbs and slowly releases water under alternating light rain and drought conditions, increasing rhizosphere available water and reducing evaporation water consumption, thus minimizing shrinkage and cracking. After colonization by the microbial system, the mycelium / biocrust structure improves the rhizosphere microenvironment and promotes water transfer and retention between the erosion-resistant and seepage-proof vegetation matrix layer and the rhizosphere, further enhancing the slope's continuous water retention capacity and vegetation resilience.

[0032] (2) Bio-engineering synergy

[0033] In the early stages of vegetation establishment, the adhesive, fibrous skeleton, and nano-modified clay work together to ensure the continuity and strength of the sprayed, erosion-resistant, and seepage-proof vegetation matrix layer, providing engineering protection against splash erosion, surface runoff, and surface reinforcement. As the composite microorganisms colonize the erosion-resistant and seepage-proof vegetation matrix layer and rhizosphere, forming a root-fungus symbiotic system with plant roots, the accumulation of microbial metabolites and organic matter, along with the root system's penetrating growth, gradually forms a "biological reinforcement network." This increases the slope's erosion and shear resistance over time, achieving a transition and enhancement from engineering protection to biological soil stabilization, reducing the need for long-term maintenance. After forming a union with plant roots (plant symbiosis), the extraroot hyphae of mycorrhizal fungi can extend 10-15 cm beyond the roots, forming a loose hyphal network. This greatly expands the root absorption range, effectively adsorbing and retaining nutrients, promoting plant growth and root development. Furthermore, this fungus can alter soil structure; its mycelium fuses and cross-links soil particles, strengthening the soil and protecting it from erosion. It also has a strong water retention capacity.

[0034] (3) Crack resistance and self-healing

[0035] The fibrous skeleton bridges and disperses stress in cracks caused by drying shrinkage, inhibiting crack initiation and propagation. The mycelial network / biocrust structure formed after microbial colonization provides some constraint and adhesion to the surface, synergistically reducing the sensitivity to drying shrinkage cracking. The nano-swelling phase, under water-swelling conditions, can fill and seal microcracks and pores, achieving a certain degree of microcrack filling. Furthermore, root penetration, root exudates, and organic matter accumulation improve the aggregate structure and stabilize pore distribution, thus maintaining the integrity and long-term stability of the corrosion-resistant and seepage-proof vegetation matrix layer and the red clay interface under wet-dry cycles.

[0036] In summary, the present invention has the following beneficial effects:

[0037] 1. Through the above technical solutions, key challenges of red clay slopes, such as sharp decrease in strength upon water softening, cracking due to drying and wetting cycles, difficulty in establishing vegetation communities due to acidity and barrenness, and susceptibility to erosion and instability under heavy rain conditions, are addressed. A thin, erosion-resistant, and seepage-proof vegetation substrate layer is constructed on the original red clay slope surface. This layer consists of a fiber skeleton, water-retaining agent, binder, nano-modified clay, composite microbial agents, and a porous carrier and embedding system. This is complemented by water mist maintenance, a three-dimensional community of "deep-rooted trees (seedlings) – shrubs and grasses – climbing plants," and a biodegradable liquid mulch. This achieves engineering protection against erosion and cracking, with moderate seepage prevention, while also promoting rhizosphere growth, biological crust formation, and root-fungus symbiosis for ecological soil stabilization. This effectively improves the long-term stability and vegetation survival rate of red clay slopes, reduces the frequency of later maintenance and repairs, beautifies the roadside environment, enriches and harmonizes the landscape, absorbs exhaust fumes, purifies the air, improves air quality, regulates soil moisture along the slope, and reduces negative environmental impacts.

[0038] 2. The compound microbial agent uses porous carriers and microcapsule encapsulation controlled release technology to improve the survival rate and colonization efficiency of active bacteria under adverse environments such as strong acidity, nutrient deficiency, ultraviolet radiation and drought. Functional bacteria such as nitrogen fixation and phosphorus solubilization, together with arbuscular mycorrhizal fungi, enhance nutrient availability and rhizosphere absorption capacity. Combined with biochar / clay porous carriers, it improves the microenvironment and buffering capacity, promoting rapid vegetation formation and stable community establishment.

[0039] 3. Spraying a biodegradable liquid mulch film onto the surface of the seeds and the erosion-resistant and seepage-proof planting substrate layer reduces early rain splash erosion, wind erosion and evaporation water consumption, and improves seedling uniformity and survival rate; the film can degrade naturally within a certain period of time, without forming a long-term root barrier layer and secondary pollution, taking into account both engineering safety and ecological restoration needs.

[0040] 4. Thin-shell spraying avoids thick backfilling and large-volume material transportation, reducing secondary disturbance to the original slope surface; the combination of renewable / carbon-fixing materials such as fiber, biochar, and lignin with microbial systems reduces reliance on high-energy-consuming materials, resulting in high overall construction efficiency and low maintenance frequency. It is suitable for rapid ecological restoration and landscape enhancement of red clay slopes in highways, railways, and mines. Attached Figure Description

[0041] Figure 1 This is a schematic cross-sectional view of the vegetation structure on the red clay roadbed slope of the present invention;

[0042] Figure 2 This is a microscopic schematic diagram of the composition of the corrosion-resistant and seepage-proof vegetation substrate layer of the present invention;

[0043] Figure 3 This is a microscopic schematic diagram of the composite microcapsule structure of the present invention;

[0044] Figure 4 This is a schematic diagram of the construction process of the present invention.

[0045] Figure 5 This is a typical infection structure diagram of Embodiment 14 of the present invention;

[0046] Figure 6 This is a diagram of the infection structure of the control group in Example 14 of the present invention;

[0047] Explanation of reference numerals in the attached diagram: 1. Red clay slope body; 2. Anti-erosion and seepage-proof vegetation matrix layer; 3. Ecological landscape layer; 4. Fiber skeleton; 5. Water-retaining agent; 6. Adhesive; 7. Nano-modified clay; 8. Composite microbial agent; 9. Porous carrier and embedding system; 10. Porous carrier; 11. Sodium alginate; 12. Chitosan; 13. Biodegradable liquid mulch film covering agent; 14. Imported soil / original soil fines and fine sand. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit the invention.

[0049] The parameters and proportions in the following embodiments can be adjusted without departing from the spirit of the present invention.

[0050] To achieve the above-mentioned objectives, this invention provides a vegetation structure for red clay roadbed slopes and its construction method. The overall technical solution is as described in the embodiments of this application, and mainly includes the following core technical elements:

[0051] like Figures 1-4 As shown, the structure comprises a three-layered synergistic structure from bottom to top, consisting of a red clay slope body 1, an anti-erosion and seepage-proof vegetation matrix layer 2, and an ecological landscape layer 3. The anti-erosion and seepage-proof vegetation matrix layer is composed of a fiber skeleton 4, a water-retaining agent 5, a binder 6, a small amount of nano-modified clay 7, a composite microbial agent 8, and its porous carrier and encapsulation system 9. This provides erosion resistance, crack resistance, and moderate seepage prevention, while also enhancing vegetation establishment.

[0052] The third ecological landscape layer is a three-dimensional community configuration of "deep-rooted trees (seedlings) + shrubs and grasses + climbing plants," and is covered with biodegradable liquid mulch 13. Herbs include Bahia grass, Bermuda grass, ryegrass (transitional season), and Kentucky bluegrass; shrubs include Amorpha fruticosa, Lespedeza bicolor, Vitex negundo, and Pigeon pea; climbing plants include Virginia creeper and leguminous vines; deep-rooted trees (seedlings) include Acacia confusa, Schima superba, and Liquidambar formosana, with local pioneer varieties selected, and small-sized seedlings to facilitate survival and root penetration; the biodegradable liquid mulch 13 consists of 10-40% lignin, 10-30% water-based natural latex, 1-5% plant-based dyes, 5-15% plant gum / thickener, with the remainder being water and additives; the spraying rate is 0.15-0.35 kg / m². 2 It forms a biodegradable protective film in the early stages, enhancing water retention and splash resistance. It degrades naturally in 30–90 days without hindering germination and growth.

[0053] As a specific embodiment of the present invention, the porous carrier 10 is composed of 1.0-5.0% attapulgite, 1.0-6.0% biochar and 5.0-20.0% organic compost, with the ratio of attapulgite:biochar:organic compost = 1:(1-3):(3-8), forming a protective microenvironment and initial nutrients;

[0054] The embedding technique uses an aqueous solution of sodium alginate 11 with a mass-to-volume ratio (w / v) of 1.5–3.0%, that is, 1.5–3.0 g of sodium alginate is added to every 100 mL of water and stirred to dissolve to form a solution with a viscosity of 200–500 mPa·s.

[0055] The bacterial-porous carrier mixture was dispersed in the above sodium alginate solution at a mass ratio of 1:5 to 1:10, and the stirring speed was controlled at 200 to 400 r / min for 10 to 15 min.

[0056] The above mixture was added dropwise to a CaCl2 solution with a mass-volume ratio of 0.5-2.0% (containing 0.5-2.0 g CaCl2·2H2O per 100 mL of water) using a peristaltic pump at a dropping rate of 2-5 mL / min. The mixture was then cross-linked and cured for 20-30 min to form primary gel cores with a particle size of 0.5-2.0 mm.

[0057] The primary gel core was placed in a chitosan-acetic acid solution with a mass-volume ratio of 0.2-0.5% (containing 0.2-0.5 g chitosan per 100 mL of 1% acetic acid solution), soaked and coated for 15-30 min, and stirred at a speed of 50-100 r / min to form microcapsule products, which enhances resistance to drought and ultraviolet radiation and achieves controlled release; then air-dried at low temperature for later use.

[0058] The remainder consists of imported soil / original soil fines and fine sand 14. If necessary, a small amount of fine sand 0-10% can be added to improve the skeleton.

[0059] As a specific embodiment of the present invention, the compound microbial agent 8 is composed of nitrogen-fixing spirochetes, phosphate-solubilizing Bacillus, irregular rhizocystis and Nostoc.

[0060] The preparation method of the compound microbial agent 8 is as follows: culture the bacteria to achieve a viable bacterial concentration of 8. ~ A single microbial agent (CFU / g) was prepared and then mixed evenly according to the following mass ratios: 35% nitrogen-fixing spirochetes, 25% phosphate-solubilizing Bacillus, 25% irregular rhizocystis fungi, and 15% Nostoc fungi, to obtain a composite microbial agent 8 with a total dosage of 0.2-1.0% of the total dry mass of the anti-erosion and seepage-proof vegetation substrate layer 2. This specific ratio of microbial community combination maximizes their synergistic effect. Nitrogen-fixing bacteria and cyanobacteria synergistically fix nitrogen, while phosphate-solubilizing bacteria dissolve phosphorus, providing nutrients for plants. The hyphal network of arbuscular mycorrhizal fungi not only helps plants absorb water and nutrients but also secretes substances such as glomerulonephrine to bind soil particles and improve soil structure. Simultaneously, the combined action of bacteria, cyanobacteria, and fungal hyphae and their secretions can form a biological crust on and inside the substrate layer, significantly improving the slope's erosion resistance and interface stability. See the comparative test results in Example 12 for details.

[0061] The aforementioned nitrogen-fixing spirochetes can be obtained from the General Microbiological Culture Collection Center (CGMCC) of the Institute of Microbiology, Chinese Academy of Sciences, with accession number CGMCC 1.10379;

[0062] The phosphate-lysinic Bacillus can be obtained from the Guangdong Provincial Microbial Culture Collection Center (GDMCC), with accession number GDMCC No. 1.183;

[0063] The irregular rhizocarp can be obtained from the Subtropical Arbuscular Mycorrhizal (AM) Fungi Resource Conservation Center (CSMC), with accession number BGSC-110;

[0064] The Nostocsp can be purchased from Shanghai Guangyu Biotechnology Co., Ltd., product model GY-D16 Nostocsp;

[0065] The public can obtain the above-mentioned strains through legitimate channels.

[0066] As a specific embodiment of the present invention, the nano-modified clay 7 is nano-montmorillonite / bentonite / attapulgite with a dosage of 2.0-5.0%, which endows the matrix with low permeability, anti-dispersion and self-healing ability (swells and fills micro-cracks when exposed to water), and forms a "water-responsive" synergy with the water-retaining agent.

[0067] In one specific embodiment of the present invention, the fiber skeleton 4 is made by alkali treatment of modified sisal / straw fiber with a content of 0.8-2.5 wt% and a length of 10-40 mm and recycled pulp fiber with a content of 1.0-3.5% and a length of 3-12 mm, forming a three-dimensional network skeleton that provides micropores for crack resistance, shear resistance and water retention; the total content of the fiber skeleton is 1.8-5.0% of the total dry mass of the corrosion-resistant and seepage-proof vegetation substrate layer.

[0068] In one specific embodiment of the present invention, the water-retaining agent 5 is a cross-linked sodium polyacrylate (SAP) with a dosage of 0.3-0.75% and a particle size of 0.3-1.5 mm, which is distributed in the matrix in a particulate state to form a "micro reservoir" and realize water absorption and release under dry and wet cycles; the adhesive 6 is made of lignin / lignin sulfonate with a dosage of 0.5-2.0%, starch or modified starch with a dosage of 0.5-2.0%, and PVA or natural latex with a dosage of 0.2-1.0% (can be used alone or in combination, with a total amount of 1.0-5.0%), forming a film with initial strength and rain erosion resistance.

[0069] In one specific embodiment of the present invention, the ecological landscape layer 3 further includes a biodegradable liquid mulch film mulch 13, which is sprayed onto the surface of seeds or seedlings of the three-dimensional plant community. Its components include: 10-40% natural lignin, 10-30% water-based natural latex, 1-5% plant-based dyes, 5-15% plant gum, and the remainder being water and additives. The spraying rate is 0.15-0.35 kg / m². 2, The additive is borax, which accounts for 0.15 to 0.25% of the total mass of the biodegradable liquid mulch film.

[0070] The second aspect of this invention provides a construction method for a vegetation structure on a red clay roadbed slope, such as... Figures 1-4 As shown, it includes the following steps:

[0071] S1, level the surface of the slope soil, remove loose soil and clods, and lightly brush the slope;

[0072] The surface of the red clay slope 1 is leveled, and protruding stones on the surface of the slope soil are removed and compacted to prepare for subsequent paving.

[0073] S2, Preparation of corrosion-resistant and seepage-proof vegetated substrate layer 2

[0074] S201, prepare fiber skeleton 4, water-retaining agent 5, binder 6, nano-modified clay 7 and mix them;

[0075] S202, prepare composite microbial agent 8, prepare composite microbial microcapsules, and mix the composite microbial microcapsules with fiber skeleton 4, water-retaining agent 5, binder 6 and nano-modified clay 7 to form an anti-corrosion and seepage-proof vegetation matrix layer.

[0076] The composite microbial microcapsule consists of a porous carrier and an encapsulation system 9. The porous carrier 10 is composed of attapulgite, biochar, and organic compost. The porous carrier is combined with the composite microbial agent, allowing the bacteria to be adsorbed on the surface and in the pores of the porous particles. The bacteria-porous carrier mixture is added to an aqueous solution of sodium alginate 11 and stirred to disperse. The above solution is then dripped into a CaCl2 crosslinking solution to solidify and form a primary gel core. The primary gel core is removed from the CaCl2 solution and immersed in a chitosan 12 solution for coating, thus forming the finished composite microbial microcapsule.

[0077] S3, Dry spraying anti-corrosion and seepage-proof vegetation substrate layer 2, water mist curing;

[0078] S301 uses specialized hydroseeding / spraying equipment with a nozzle pressure of 0.3–0.6 MPa. It is evenly sprayed onto the red clay slope. For slopes >60° or windy sections, it can be sprayed in two thin layers.

[0079] S302, the designed thickness is 5-15 mm (8-20 mm in local busbar areas).

[0080] S303, spray with fine mist water within 0-24 hours after spraying to keep the surface moist and prevent runoff, and continue maintenance for 5-10 days, 2-4 times during the day and once at night;

[0081] S4, lay plant landscape layer 3, mix and plant, spray liquid mulch 13;

[0082] For S401, spray mixed grass seeds and plant shrub / tree seedlings 24–48 hours after substrate spraying, at a sowing depth of 0.5–1.0 cm; for tree seedling planting sites, pre-drill holes to penetrate the substrate layer and enter the original soil.

[0083] S402, after sowing and transplanting, liquid mulch film mulch 13 is sprayed onto the surface of the substrate layer to form an initial biodegradable protective film, which degrades naturally in 30-90 days.

[0084] In one optional embodiment, the method for preparing microcapsules encapsulating composite microbial agents includes: adsorbing the composite microbial agents onto a porous carrier to obtain a microbial-carrier mixture; dispersing the microbial-carrier mixture in an aqueous sodium alginate solution, and then adding it dropwise into a calcium chloride solution for cross-linking and solidification to form a gel core; and immersing the gel core in a chitosan solution for coating to form microcapsules.

[0085] In an optional embodiment, in step two, the microcapsules containing the composite microbial agent are added last before spraying to avoid prolonged contact with alkaline materials.

[0086] Unless otherwise specified, all materials, reagents and instruments used in the embodiments of this invention can be obtained through commercial channels.

[0087] Example 1:

[0088] Weigh out the sisal fibers, treat them with 2% NaOH solution for 2 hours, wash and dry them. 1.8g of recycled pulp fiber (6-10mm in length) with a length of 25-35mm is mixed to form the fiber skeleton 4; 0.75g of cross-linked sodium polyacrylate with a particle size of 0.5-1.0mm is weighed as the water-retaining agent 5; 1g of lignin sulfonate and 1.5g of modified starch are weighed and mixed to form the binder 6; 5g of surface-modified bentonite is weighed as the nano-modified clay 7, and mixed evenly with the above components; a compound microbial agent containing nitrogen-fixing spirochetes, phosphate-solubilizing Bacillus, irregular rhizocystis, and Nostoc is weighed. 0.5g of CFU / g was prepared. 5g of organic compost, 1g of attapulgite soil, and 2g of biochar were weighed and mixed as a carrier for the microbial agent. After encapsulation with sodium alginate and chitosan, a composite microbial microcapsule containing the composite microbial agent was formed. 80.25g of imported soil and fine sand were weighed and mixed evenly with the above components to form 100g of homogeneous spraying mixture. The substrate was laid on the red clay surface of the test platform using a hydroseeding device, with a spraying thickness of 10mm. The curing conditions were fine mist spraying for 7 days. The tensile strength, shrinkage strain, and permeability coefficient of the above-mentioned anti-corrosion and seepage-proof vegetation substrate layer were tested.

[0089] The results showed that the tensile strength of the corrosion-resistant and seepage-proof vegetated substrate layer 2 was 0.25 MPa, the drying shrinkage strain was 0.17%, and the permeability coefficient was [missing value]. cm / s; Compared with ordinary imported soil matrix, the corrosion-resistant and seepage-proof vegetation matrix layer of this application has higher tensile strength and lower drying shrinkage strain, while the permeability coefficient is significantly lower than that of ordinary imported soil matrix, which has significant technical advantages.

[0090] Example 2:

[0091] This embodiment aims to verify the lower limit of the dosage of nano-modified clay 7. The impact of corrosion-resistant and seepage-proof vegetated substrate layer 2 on its function, to support the application in this paper. Scope of feasibility.

[0092] Based on the admixture ratio and amount in Example 1, a control group was set up, and the amount of nano-modified clay 7 was adjusted to 2g and 5g respectively, while the amounts of other components remained unchanged. Topsoil was added to make the total weight of the mixed dry material 100g. The same curing conditions and testing methods as in Example 1 were used.

[0093] The results showed that the tensile strengths of the corrosion-resistant and seepage-proof vegetated substrate layers 2 with nano-modified clay content of 2.0% and 5.0% after 7 days of curing were respectively... and The drying shrinkage strains were 0.18% and 0.12%, respectively, and the permeability coefficient was... cm / s and cm / s; With the increase of nano-modified clay content, the tensile strength of the matrix increases, while the drying shrinkage strain and permeability coefficient decrease. Even at the lower limit of 2.0% for nano-modified clay 7, this vegetated matrix still exhibits excellent comprehensive performance through enhanced wind erosion resistance, crack resistance, and water retention capacity, supporting the feasibility of the 2.0~5.0% content range in the claims of this invention.

[0094] Example 3:

[0095] This embodiment aims to verify the upper limit of the total content of fiber skeleton 4. The impact on spray applicationability and matrix structure, to support the claims in this application. Scope of feasibility.

[0096] Based on the blending ratio and amount in Example 1, the total amount of fiber skeleton 4 was adjusted to 5g, while the amounts of other components remained unchanged. Topsoil was added to make the total weight of the mixed dry material 100g. The same curing conditions and testing methods as in Example 1 were used, and the spray flowability was tested.

[0097] The results showed that using 5.0% fiber content resulted in no clogging issues, good spray flowability, and uniform fiber dispersion. The tensile strength of the corrosion-resistant and seepage-proof vegetated substrate layer 2 increased to 0.27 MPa after 7 days of curing. This was because the fiber increased the reinforcing skeleton of the substrate and further dispersed the tensile stress. The drying shrinkage strain was 0.19%, and the increase in fiber content did not have a negative impact on the drying shrinkage performance. The substrate structure remained relatively stable.

[0098] In conclusion, a fiber skeleton content of 1.0% to 5.0% is a reasonable and feasible range, which can effectively balance the workability and structural performance of the matrix.

[0099] Example 4:

[0100] This embodiment aims to verify the lower limit of the dosage of water-retaining agent 5. The impact on the water retention properties of the substrate, to support the claims in this application. Scope of feasibility.

[0101] Based on the admixture ratio and dosage of Example 1, a control group was set up. The total dosage of water-retaining agent 5 was adjusted to 0.3g and 0.75g respectively, while the dosages of other components remained unchanged. Topsoil was added to make the total dry weight of the mixture 100g. Under the same curing conditions as in Example 1, the substrate's moisture retention capacity, water retention time, and substrate saturation permeability were tested.

[0102] The results showed that with a water-retaining agent dosage of 0.3%, the moisture retention capacity of the corrosion-resistant and seepage-proof vegetation substrate layer 2 was 42.7% after 7 days of curing, slightly higher than the evaluation standard (40%), demonstrating good water retention performance. The moisture retention capacity of the substrate with a dosage of 0.75% was 48.3%. With a water-retaining agent dosage of 0.3%, the substrate sample could retain moisture for 8 days, exceeding the evaluation standard of 7 days, and still had excellent moisture retention capacity. The permeability coefficient measured under saturated conditions was [value missing]. The water density is cm / s, and the substrate can prevent rapid water loss even after absorbing water. A substrate with a dosage of 0.75% retains water for 12 days, and the permeability coefficient decreases to [value missing]. cm / s. The water retention time increases with the increase of the water-retaining agent dosage, while the permeability coefficient decreases with the increase of the dosage.

[0103] Example 5:

[0104] This embodiment aims to verify the lower limit of the spraying dosage of biodegradable liquid mulch film mulch agent 13. The impact on initial conservation outcomes, to support the claims in this application. Scope of feasibility.

[0105] Weigh out 25g of natural lignin, 20g of water-based natural latex, 3g of plant-based dye, 10g of plant gum, and 42g of water and additives, and mix them as a biodegradable liquid mulch film covering agent; apply at a concentration of 0.15kg / m². 2 The application rate was uniformly sprayed onto the surface of the artificial red clay slope vegetation substrate using a spraying device (same ratio as in Example 1); a control group without covering agent was set up to test the rain erosion resistance, moisture retention performance, vegetation emergence rate and surface cracking rate.

[0106] The results showed that the soil loss rate of the biodegradable liquid mulch film mulch 13 was 22.5%, the substrate moisture content was 38.7%, the seedling emergence rate was 80.4%, and the surface crack rate was 7.5%, all of which were significantly better than the control group without mulch film. The amount of spraying can significantly improve the ecological performance of red clay slope structures.

[0107] Example 6:

[0108] This embodiment aims to verify the lower limit of water mist curing time in the construction method. The effects on microbial activation and seed germination support the feasibility of the 5-10 day range in this application.

[0109] The corrosion-resistant and seepage-proof vegetation substrate layer 2 from Example 1 was subjected to water mist curing for 5 days. After curing, mixed sowing and transplanting were carried out. The control group without water mist curing was used. The microbial activity and seed germination rate in the vegetation substrate were tested. The results showed that the corrosion-resistant and seepage-proof vegetation substrate layer 2 after 5 days of water mist curing had a microbial activity index of 74.8% and a seed germination rate of 82.3%. Compared with the control group without water mist curing, the microbial activity and seed germination rate of the vegetation substrate after 5 days of water mist curing were significantly improved.

[0110] Example 7:

[0111] This embodiment aims to verify the impact of a minimum spray thickness of 5 mm on the functional integrity of the matrix layer in the construction method, so as to support the feasibility of the 5-15 mm range in this application.

[0112] Based on the mixing ratio of Example 1, an anti-corrosion and seepage-proof vegetation substrate layer 2 was prepared; the substrate was evenly sprayed on the artificial red clay slope, with three spray thicknesses of 5mm, 10mm and 15mm, and continuously cured for 5 days to stabilize the initial performance of the substrate; the rain erosion resistance, wind erosion resistance and substrate adhesion of different spray thicknesses were measured.

[0113] The results showed that the rain erosion and erosion loss rates of the anti-corrosion and seepage-proof vegetation substrate layer 2 with spray thicknesses of 5 mm, 10 mm, and 15 mm were 25.4%, 12.7%, and 8.6%, respectively; the wind erosion resistance rates were 78.6%, 87.3%, and 92.4%, respectively; and the substrate adhesion rates were 45.3 kPa, 58.7 kPa, and 66.4 kPa, respectively. The substrate spray thicknesses of 10 mm and 15 mm achieved good results in terms of rain erosion resistance, wind erosion resistance, and adhesion. Although the spray thickness of 5 mm could basically meet certain functional requirements, it was slightly lower than the standard in some indicators and was only suitable for light slope environments with lower requirements for wind erosion and erosion resistance.

[0114] Example 8:

[0115] This embodiment aims to verify the lower limit of chitosan concentration in microcapsule preparation. The impact on embedding performance, to support the claims in this application. Scope of feasibility.

[0116] Chitosan 9 concentrations were set at 0.2%, 0.3%, 0.4%, and 0.5%, respectively, and microcapsules were prepared using an emulsification-crosslinking method. The encapsulation efficiency, microcapsule size, shell wall integrity, and solubility stability were measured. The results showed that chitosan concentrations within the range of 0.2%–0.5% could form microcapsules, with concentrations ≥0.3% exhibiting superior encapsulation effects and significantly improved shell wall integrity and storage stability. Therefore, a chitosan concentration range of 0.2–0.5% is feasible, and a concentration of 0.3–0.5% is recommended.

[0117] Example 9:

[0118] This embodiment aims to verify the upper limit of sodium alginate concentration in microcapsule preparation. The impact on the sphericity and release properties of microcapsules, to support the claims in this application. Scope of feasibility.

[0119] Microcapsules were prepared using a spray-gel method with sodium alginate solution concentrations of 1.5%, 2.0%, 2.5%, and 3.0%, respectively. The performance of the microcapsules was evaluated by observing sphericity (appearance and sphericity index), detecting the release rate of the active substance, and assessing the residual rate.

[0120] The results showed that the sphericity of microcapsules gradually improved with increasing sodium alginate concentration, and the sphericity index tended to stabilize at a concentration ≥2.0%. Release performance was significantly optimized at sodium alginate concentration ≥2.5%, while the increased viscosity at concentrations above 3.0% had little impact on the preparation process and release performance. In summary, sodium alginate concentrations in the range of 1.5%–3.0% are feasible, with a recommended concentration of 2.0%–2.5%.

[0121] Example 10:

[0122] This embodiment aims to verify the effect of the timing of "last addition" of microcapsules in the construction method on the viable bacteria retention rate, so as to support the technical effect of the embodiment.

[0123] Under the same formulation and external environmental conditions, the microcapsules were added at the final construction stage ("final addition" method) and the mixing stage (conventional method), and the viable bacteria retention rate (CFU counting method) was tested.

[0124] The results showed that the average viable cell retention rate was 89.6% in the last addition method, significantly higher than the 65.8% in the traditional method. In the traditional method, the prolonged stirring time and stress caused microcapsule breakage, resulting in a significant decrease in viable cell retention. In conclusion, adding microcapsules last effectively protects viable cell activity and significantly improves viable cell retention, providing reliable support for the technical effectiveness of the application method.

[0125] Example 11:

[0126] This embodiment aims to systematically evaluate the comprehensive performance and technical effects of the red clay roadbed slope vegetation structure of the present invention.

[0127] A typical red clay slope from an actual engineering project was selected as the test site. A slope vegetation structure was constructed and compared with traditional vegetation techniques. Evaluation included comprehensive performance indicators such as vegetation coverage, growth uniformity, substrate stability, and resistance to rainwater erosion. The specific implementation steps are as follows:

[0128] The red clay slope was divided into two areas: one area adopted the vegetation structure of this invention (Area A), and the other area adopted the traditional vegetation technology (Area B). The natural conditions of the two areas were kept consistent. The vegetation coverage, growth uniformity (standard deviation of plant height and density), matrix stability (shear strength measurement), and resistance to rainwater erosion (soil loss test) of the two areas were monitored regularly. Long-term continuous observation was carried out to establish a quantitative index system and compare the differences in the effects of the two technologies.

[0129] The results showed that the average vegetation coverage in region A was 95%, significantly higher than that in region B (78%). The stability of the vegetation matrix in region A was enhanced, and the shear strength increased by 30%. In the rainfall erosion test, the soil and water loss in region A decreased by 42%, and the resistance to rainwater erosion was significantly improved.

[0130] In summary, the red clay roadbed slope vegetation structure of the present invention exhibits excellent comprehensive performance in terms of increasing vegetation coverage, enhancing matrix stability, and reducing soil erosion, providing reliable technical support for slope ecological restoration.

[0131] Example 12:

[0132] This embodiment aims to systematically evaluate the technical effects of the compound microbial agent of the present invention.

[0133] Weigh out the compound microbial inoculant containing 0.175g of *Azotocinobacter*, 0.125g of *Bacillus lysophosphatidylcholine*, 0.125g of *Rhizocystis irregularis*, and 0.075g of *Nostoc*. The CFU / g ratio of the substrate was used, with the remaining components used in the same amounts as in Example 1. This was used to prepare an anti-corrosion and seepage-proof vegetation matrix layer, which was sprayed onto the test slope. An ecological landscape layer was then sown and planted on top of this matrix. Maintenance and testing conditions were identical to those in Example 1. Control groups were set up: Control group 1: identical to the formulation in Example 12, but without any added microbial agents; Control group 2: identical to the formulation in Example 12, but with the addition of an equal amount of irregular rhizocarp fungicide; Control group 3: bare red clay slope without any treatment. The vegetation coverage, matrix layer condition, interfacial shear strength, and content of water-stable macroaggregates greater than 0.25 mm were tested 180 days after construction. The results are shown in the table below.

[0134] The results show that the composite microbial agent of the present invention can form a biological crust to play a role in restraint and bonding, thereby improving the slope's resistance to erosion and shear; it also improves the aggregate structure and maintains the integrity and long-term stability of the interface between the erosion-resistant and seepage-proof vegetation matrix layer and the red clay.

[0135] Example 12 above demonstrates that, under the microbial community and its ratio defined in this invention (35% nitrogen-fixing bacteria, 25% phosphate-solubilizing bacteria, 25% arbuscular mycorrhizal fungi, and 15% cyanobacteria), compared to the control group without added microbial agents or with only a single microbial agent, significantly better synergistic effects were achieved in terms of vegetation cover, interfacial shear strength, and soil aggregate content. This indicates that this specific ratio is one of the key technical features for achieving synergistic soil stabilization effects between slope ecology and engineering.

[0136] Example 13: Experimental Verification of Synergistic Effect between Nano-Modified Clay and Water-Retaining Agent

[0137] This embodiment aims to verify the synergistic effect of nano-modified clay 7 and water-retaining agent 5 in the protection of red clay slopes, especially the advantages of using the two together compared with using them alone in inhibiting drying shrinkage cracking and maintaining moisture balance.

[0138] Using the formulation of Example 12, an anti-corrosion and seepage-proof vegetation substrate layer was prepared. Control groups were set up: Control group 1: completely identical to the formulation of Example 13, using only nano-modified clay, without adding water-retaining agent; Control group 2: completely identical to the formulation of Example 13, using only water-retaining agent, without adding nano-modified clay; Control group 3: bare red clay slope, without adding nano-modified clay and water-retaining agent. The curing and testing conditions were completely identical to those of Example 1. The soil porosity and water retention rate (moisture content retention capacity) were tested 180 days after construction.

[0139] The results showed that the crack rate of Example 13 was 7.5% and the water retention rate was 51%. Compared with the use of the two alone, the combined use of nano-modified clay and water-retaining agent had a significant synergistic effect. It not only performed well in inhibiting the drying shrinkage and cracking of red clay, but also effectively improved the water retention capacity and soil structure stability.

[0140] Example 14: Experiment to determine the infection rate of arbuscular mycorrhizal fungi

[0141] This embodiment aims to verify, at the microscopic level, the symbiotic relationship between the arbuscular mycorrhizal fungi (AM fungi) in the composite microbial agent 8 of the present invention and the plant roots of the ecological landscape layer 3.

[0142] Using the same formulation as in Example 12, weigh out the same compound microbial agent and select a three-dimensional plant community consisting of deep-rooted trees, shrubs, herbs and climbing plants; set up control groups: control group 1: no compound microbial agent was inoculated, but the same plants were planted; control group 2: the compound microbial agent was inoculated with arbuscular mycorrhizal fungi removed and contained only other functional strains; the arbuscular mycorrhizal fungi infection rate was measured 180 days after construction.

[0143] The results showed that after inoculation with arbuscular mycorrhizal fungi, the infection rate reached 82.5%, which was much higher than the 5.7% of the control group 2. Typical infection structures observed were as follows: Figure 5 As shown. No typical infection was observed in control group 1, which was not inoculated with arbuscular mycorrhizal fungi, such as... Figure 6 As shown in the figure, this indicates that the arbuscular mycorrhizal fungi in the compound microbial agent can form a good symbiotic relationship with plant roots, thereby improving soil nutrient utilization and plant growth performance.

[0144] Example 15: This example provides experimental evidence that nano-modified clay reduces the pore connectivity of red clay surface.

[0145] The pore structure parameters of red clay samples before and after the addition of nano-modified clay were determined by mercury intrusion porosimetry (MIP).

[0146] Experimental group: 5% nano-modified clay added to red clay (Formula of Example 1);

[0147] Control group: pure red clay, without nano-modified clay.

[0148] Sample preparation: Red clay was sieved through a 2mm sieve and prepared at the optimum moisture content of 22%. The experimental group was mixed with 5% nano-modified clay and thoroughly mixed, while the control group was not mixed. Φ50mm×50mm cylindrical samples were prepared, cured under standard conditions for 28 days, and then dried at 105℃ to constant weight for mercury porosimetry testing.

[0149] Mercury porosimetry test conditions: AutoPore IV9500 fully automatic mercury porosimetry instrument was used, with a maximum mercury inlet pressure of 414 MPa, a contact angle of 130°, and a surface tension of 485 dyn / cm.

[0150] The results show that:

[0151] The total porosity of the experimental group was 38.5%, while that of the control group was 42.3%.

[0152] The pore connectivity (the percentage of connected pores calculated from mercury intrusion porosimetry) in the experimental group was 62.4%, while that in the control group was 78.6%.

[0153] In the pore size distribution of the experimental group, macropores >50 μm accounted for 12.3%, while those in the control group were 21.5%.

[0154] In the experimental group, the proportion of medium and fine pores (50 nm to 10 μm) was 58.2%, while in the control group it was 48.7%.

[0155] The above results show that after the nano-modified clay swells and becomes moist with water, it fills some of the large pores and interconnected pores in the red clay, reduces pore connectivity, reduces rainwater infiltration channels, and achieves the technical effect of "moderate seepage prevention".

[0156] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vegetation structure for red clay roadbed slopes, characterized in that, include: Red clay slope body (1); The corrosion-resistant and seepage-proof vegetation matrix layer (2) is a thin shell with a thickness of 5~15mm covering the surface of the red clay slope body (1). Its raw material composition includes fiber skeleton (4), water-retaining agent (5), binder (6), nano-modified clay (7), and composite microbial agent (8); among which, The nano-modified clay (7) is used to swell and fill microcracks when exposed to water, thereby reducing the pore connectivity of the red clay surface layer. The composite microbial agent (8) is composed of a functional microbial community consisting of 35% nitrogen-fixing bacteria, 25% phosphate-solubilizing bacteria, 25% arbuscular mycorrhizal fungi, and 15% cyanobacteria by mass percentage. The composite microbial agent (8) is encapsulated in microcapsules composed of a porous carrier (10) and an outer encapsulation membrane. This is used to colonize the surface of the red clay slope body (1) and form a mycelial network and biocrust that coexists with the roots of subsequent plants. The ecological landscape layer (3) is laid on top of the corrosion-resistant and seepage-proof vegetation substrate layer (2), including a three-dimensional plant community composed of deep-rooted trees, shrubs, herbs and climbing plants; Among them, the mycelial network formed by the nano-modified clay (7), the composite microbial agent (8) and the plant root system work together to form a composite structure of water stability enhancement and biological soil stabilization on the surface of the red clay slope body (1).

2. The vegetation structure for red clay roadbed slopes according to claim 1, characterized in that, The porous carrier (10) is a mixture of attapulgite soil, biochar and organic compost accounting for 1.0~5.0% of the total dry mass of the anti-corrosion and seepage-proof vegetation substrate layer (2); the outer layer of the embedding membrane is a double-layer embedding structure formed by sodium alginate and chitosan.

3. The vegetation structure for red clay roadbed slopes according to claim 1, characterized in that, The nitrogen-fixing bacteria are *Azotospira*; the phosphate-solubilizing bacteria are *Bacillus phosphate-solubilizing*; the arbuscular mycorrhizal fungi are *Rhizocarpium irregularis*; and the cyanobacteria are *Nostoc*.

4. The vegetation structure for red clay roadbed slopes according to claim 1, characterized in that, The nano-modified clay (7) is one or more of the surface-modified nano-montmorillonite, nano-bentonite, or nano-attapulgite, and its dosage is 2.0-5.0% of the total dry mass of the anti-corrosion and seepage-proof vegetation substrate layer (2); the surface modification is at least one of the following methods: ion exchange intercalation, silane coupling grafting, and polymer coating; the modifier is selected from one or more of the following: quaternary ammonium salt cationic surfactant, cationic polymer, silane coupling agent, and film-forming polymer; the amount of modifier used in ion exchange intercalation is 0.5-10% of the clay mass; the grafting amount of silane grafting is 0.2-5%; the water contact angle of the modified clay is 40-110°, and it retains the ability to swell and fill microcracks when exposed to water.

5. The vegetation structure for red clay roadbed slopes according to claim 1, characterized in that, The fiber skeleton (4) includes alkali-treated plant long fibers and recycled pulp fibers. The plant long fibers are 10 to 40 mm long, and the recycled pulp fibers are 3 to 12 mm long. The total amount of the fiber skeleton (4) is 1.8 to 5.0% of the total dry mass of the anti-corrosion and seepage-proof plant matrix layer (2).

6. The vegetation structure for red clay roadbed slopes according to claim 1, characterized in that, The water-retaining agent (5) is sodium polyacrylate super absorbent resin with a particle size of 0.3 to 1.5 mm, and the dosage is 0.3 to 0.75% of the total dry mass of the anti-corrosion and seepage-proof vegetation substrate layer (2); the adhesive (6) is one or more combinations of lignin sulfonate, modified starch, polyvinyl alcohol and natural latex, and the total dosage is 1.0 to 5.0%.

7. The vegetation structure for red clay roadbed slopes according to claim 1, characterized in that, The ecological landscape layer (3) also includes a biodegradable liquid mulch film covering agent (13), which is sprayed on the surface of the matrix layer to form an initial biodegradable protective film. Its components include: 10-40% natural lignin, 10-30% water-based natural latex, 1-5% plant-based dye, 5-15% plant gum, and the remainder is water and additives. The spraying amount is 0.15-0.35 kg / m², of which the additive is borax, and borax accounts for 0.15-0.25% of the total mass of the biodegradable liquid mulch film covering agent.

8. A construction method for a vegetation structure on a red clay roadbed slope as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1, Slope preparation: Level the surface of the red clay slope (1); Step 2: Preparation of anti-corrosion and seepage-proof vegetation substrate mixture: Mix fiber skeleton (4), water-retaining agent (5), binder (6), and nano-modified clay (7), and add microcapsules containing composite microbial agent (8) before spraying to obtain dry mixture; Step 3, spray molding: Using dry spraying process, dry mixture is sprayed onto the surface of red clay slope body (1) to form a corrosion-resistant and seepage-proof vegetation matrix layer (2) with a thickness of 5-15 mm. Step 4, Water Mist Curing: After spraying, continue fine mist watering for 5-10 days; Step 5, Ecological landscape construction: After maintenance, sow and plant three-dimensional plant communities, and spray biodegradable liquid mulch film covering agent (13) to form an initial protective film.

9. The construction method of the vegetation structure for red clay roadbed slope according to claim 8, characterized in that, The method for preparing the microcapsules containing the composite microbial agent (8) includes: adsorbing the composite microbial agent (8) onto a porous carrier (10) to obtain a microbial-porous carrier mixture; dispersing the microbial-porous carrier mixture in an aqueous sodium alginate solution and dripping it into a calcium chloride solution to crosslink and solidify it to form a gel core; and placing the gel core in a chitosan solution for soaking and coating to form a microcapsule.

10. The construction method of the red clay roadbed slope vegetation structure according to claim 8, characterized in that, In step two, the microcapsules containing the composite microbial agent (8) are added last before spraying to avoid prolonged contact with alkaline materials.

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