Moss-microorganism synergistic nitrogen fixation bionic regreening method and system for drought-resistant mine rock slope

Abstract

The invention discloses a moss-microorganism synergistic nitrogen fixation bionic regreening method and system for a drought-resistant mine rock slope, and belongs to the technical field of ecological environment restoration. The method comprises the following steps: (1) slope pretreatment: drilling anchoring holes; (2) layered construction: (1) a fixation layer: spraying mixed slurry prepared from amylase and plant fibers to form a net-shaped substrate with the thickness of 1-2cm; (2) a nutrient layer: spraying a mixture of a complex microbial inoculant and a slow release fertilizer, wherein the thickness is 4cm; the mixed bacterial agent is prepared from the following raw materials in percentage by weight: 60 percent of phytonimum patenum spores, 25 percent of nostoc commune (Nostoc commune) and 15 percent of pseudomonas fluorescens (Pseudomonas fluorescens), and the mixed bacterial agent is prepared from the following raw materials in percentage by weight: 60 percent of phytonimum patenum spores, 25 percent of nostoc commune (Nostoc commune) and 15 percent of pseudomonas fluorescens (Pseudomonas fluorescens). And (3) a water retention layer: sodium polyacrylate resin is spread, the particle size of the sodium polyacrylate resin is 1-0.5 mm, soil covering and compaction are performed until the thickness of the water retention layer is 1-1.5 cm, and the use amount of the sodium polyacrylate resin is 2-1.5 wt% of the weight of the soil. According to the method, the nitrogen fixation efficiency can be improved by 40-60%, and the soil moisture content is kept gt under the drought condition; the survival rate of the seedlings is increased to 85% or above, the anti-scouring capacity of the side slope is improved by 50%, and the vegetation coverage rate of 70% or above is achieved within 6 months.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ecological environment restoration, and particularly relates to a moss-microorganism synergistic nitrogen fixation biomimetic re-greening method and system for a drought-resistant mine rock slope. BACKGROUND

[0002] Mining is an important way of resource development, but long-term open mining will form a large number of bare rock slopes. The surface of such slopes is hard and has no natural soil layer, and because the rock weathering degree is low and the structure is dense, the water holding capacity is very poor (usually the saturated water content is <10%), the organic matter content is very low (<0.5%), and at the same time, the matrix is easily stripped and lost (the matrix stripping rate of the traditional guest soil method is as high as 30-50%) under the influence of alternating heavy rain and drought, becoming a difficult place for ecological restoration.

[0003] Traditional ecological restoration technologies for rock slopes mainly include the following types:

[0004] (1) Guest soil spraying technology: the soil is artificially transported to cover the slope, and grass seeds are sprayed to realize greening. However, this technology relies on external soil supply, and the transportation cost is high; and the rock surface has poor adhesion with the guest soil, and matrix stripping easily occurs under heavy rain, and the water in the guest soil quickly evaporates in the drought period, so the survival rate of vegetation is usually less than 40% (especially in arid areas with annual rainfall <400 mm).

[0005] (2) Vegetation concrete technology: cement, aggregate, plant fiber and grass seeds are mixed and sprayed to form a soil-like matrix. However, the strong alkalinity (pH>9) of cement will inhibit plant growth, and the hardened matrix has poor air permeability, which is difficult to support microbial activity, and long-term use will easily lead to soil compaction.

[0006] (3) Single biological restoration technology: such as simply transplanting moss or inoculating nitrogen-fixing bacteria. However, moss is sensitive to water and easily dehydrated and dies on the dry rock surface; single nitrogen-fixing bacteria (such as rhizobium) need to rely on symbiosis with host plants, and the nitrogen fixation efficiency is very low (only 5-10 mg / m² / d) in the initial stage of the rock slope without vegetation.

[0007] (4) Chemical nitrogen fixation supplement: nitrogen deficiency is alleviated by applying chemical nitrogen fertilizer such as urea and ammonium salt. However, chemical fertilizer is easily lost with runoff, not only causing resource waste, but also polluting surrounding water bodies (such as causing river eutrophication).

[0008] In addition, the existing technology generally lacks dynamic regulation and control ability for the restoration process, and the traditional method mostly adopts a one-time construction and regular artificial irrigation mode, which cannot adjust the maintenance strategy in real time according to the soil moisture and microbial activity, resulting in problems such as water waste or deficiency in the drought period, and microbial inactivation due to sudden environmental changes, further prolonging the restoration period (the traditional method usually needs 12-18 months to achieve more than 50% vegetation coverage).

[0009] In summary, the ecological restoration of rock slope urgently needs a comprehensive technical system that takes into account drought resistance, water conservation, efficient nitrogen fixation, substrate stabilization, and intelligent control, to solve the three core problems of drought stress, nitrogen deficiency, and slope instability, and to shorten the restoration period and reduce environmental risks. SUMMARY

[0010] The present application provides a drought-resistant mine rock slope moss-microorganism synergistic nitrogen fixation biomimetic re-greening method, which comprises the following steps:

[0011] (1) Slope pretreatment: drilling anchor holes;

[0012] (2) Layered construction:

[0013] ① Fixing layer: spraying a mixed slurry made of amylase and plant fibers to form a reticular substrate with a thickness of 1-2 cm; the specific preparation process of the mixed slurry is as follows: a. Add 4-6 wt% plant fibers to water and stir to form a suspension; b. Mix 8-12 wt% starch with water, heat to 60-70℃, add 12-15 wt% amylase, stir for at least 20 minutes, and heat to 90℃ to form a gelatinized starch solution; c. Slowly add the plant fiber suspension to the gelatinized starch solution and stir to obtain the mixed slurry, wherein the dry weight ratio of plant fibers to amylase is 100:1.8~2.5;

[0014] ② Nutrient layer: spraying a mixture of compound microbial agent and slow-release fertilizer with a thickness of 4 cm; the preparation process of the mixture is as follows: a. Mix 60wt% Physcomitrium patens spores, 25wt% Nostoc commune, and 15wt% Pseudomonas fluorescens with soluble starch to dry to obtain spore powder, and then mix evenly to obtain a mixed microbial agent; b. Use β-cyclodextrin to wrap slow-release fertilizer particles to form an inner slow-release film, and spray a gelatin-polyvinyl alcohol cross-linked film on the outside to control nutrient release, with the film accounting for 2-3% of the weight of the fertilizer and the film thickness being 50-100μm; c. Dry mix the mixed microbial agent and the fertilizer at a mass ratio of 1:4-1:6, spray guar gum solution for bonding, and add 0.1-0.5% xanthan gum to enhance the suspension; the fertilizer is ;

[0015] ③ Water retention layer: spread polyacrylic acid sodium resin with a particle size of 1-0.5mm, and compact the soil to a thickness of 1-1.5cm, wherein the amount of polyacrylic acid sodium resin is 2-1.5wt% of the weight of the soil.

[0016] In one embodiment of the present application, the hole diameter in step (1) is 3cm, the depth is 20cm, and the hole spacing is 30×30cm, arranged in a quincunx pattern.

[0017] In one embodiment of the present invention, the plant fiber in step (2) is bamboo fiber.

[0018] In one embodiment of the present invention, the amount of plant fiber used in step ① is 5 wt%; the amount of starch used is 10 wt%.

[0019] In one embodiment of the present invention, in step ①, the starch and water are mixed and then heated to 65°C.

[0020] In one embodiment of the present invention, the dry weight ratio of plant fiber to amylase in step ① is 100:2.

[0021] In one embodiment of the present invention, in step ②, the mixture ratio of bacterial agent to fertilizer is 1:5.

[0022] In one embodiment of the present invention, the method further includes step (3) of burying a soil moisture sensor in the nutrient layer and setting the irrigation threshold to 12%.

[0023] The present invention also provides application of the above method in ecological restoration of rock slopes.

[0024] The present invention also provides a drought-resistant moss-microorganism collaborative nitrogen fixation biomimetic regreening system for rocky slopes in mines, which includes a microbial composite unit, a hierarchical structure unit, and an intelligent monitoring unit; the microbial composite unit is composed of the above-mentioned Physcomitrium patens spores, Nostoc commune, and Pseudomonas fluorescens; the hierarchical structure unit is composed of the above-mentioned fixation layer, nutrient layer, and water retention layer from bottom to top; the intelligent monitoring unit includes a soil moisture sensor, a microbial activity detection module, and an Internet of Things controller.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) Nitrogen fixation efficiency is increased by 40%-60%: The present invention maintains an efficient nitrogen cycle in arid environments through the synergistic nitrogen fixation of moss and cyanobacteria.

[0027] (2) Enhanced drought resistance: The composite water-retaining agent of the present invention keeps the soil moisture content >15% under drought conditions and increases the seedling survival rate to over 85%.

[0028] (3) Improved slope stability: The moss root network of the present invention increases the slope's anti-scouring ability by 50%, reducing soil erosion.

[0029] (4) Shorten the ecological restoration period: The method realizes more than 70% vegetation coverage within 6 months, which is 40% shorter than the traditional method. DETAILED DESCRIPTION

[0030] Example 1: Granite slope greening experiment (dry environment)

[0031] 1. Experimental preparation

[0032] Site: A certain abandoned granite mine in Shangrao, Jiangxi (slope 65°±2°, rock pH 7.2-7.8).

[0033] Material preparation:

[0034] Composite microbial agent: Physcomitrium patens spores 60wt% + Nostoc commune 25wt% + Pseudomonas fluorescens 15wt%.

[0035] Water-retaining layer: polyacrylic acid sodium resin (water absorption ratio ≥300 times).

[0036] Anchoring material: amylase (CAS number 9000-92-4, EINECS number starch modifier) (concentration 12%) + bamboo fiber (length 5mm).

[0037] 2. Construction process

[0038] (1) Slope pretreatment: Drill anchor holes (hole diameter 3cm, depth 20cm, hole spacing 30x30cm in a plum blossom shape), remove surface floatstone.

[0039] (2) Layered construction: Spray the amylase + bamboo fiber mixed slurry (pressure 0.8MPa) to form a 1.8cm thick mesh matrix; the specific preparation process is as follows: a. Add 5% (by weight of water) bamboo fiber to water, high-speed stirring (>1000 rpm) to form a uniform suspension; b. Mix 12% (by weight of water) starch with water, heat to 70℃, add amylase, the addition amount of amylase is 12% (by weight of water), constant temperature stirring for 30 minutes, heating to 90℃, forming a gelatinized starch solution; c. Slowly add the cellulose fiber suspension to the gelatinized starch solution, medium-speed stirring (300-600 rpm), forming an amylase + cellulose fiber mixed slurry, bamboo fiber: amylase = 100:2 (dry weight ratio). The nutrient layer is high-pressure composite microbial agent (containing slow-release fertilizer ), thickness 4 cm; the specific preparation process is as follows: a. the above three bacteria are mixed and dried with soluble starch to prepare spore powder, and then mixed to prepare a mixed microbial agent; b. the slow-release fertilizer particles are wrapped with β-cyclodextrin to form an inner slow-release film, and the outer layer is sprayed with a gelatin-polyvinyl alcohol cross-linked film to control nutrient release (the coating layer accounts for 2% of the weight of the fertilizer, and the film thickness is 50 μm); c. dry mixing according to the mass ratio of mixed microbial agent:fertilizer=1:5, spraying guar gum solution for bonding, and adding xanthan gum (0.1%) to enhance the suspension. The water-retaining layer is sprayed with sodium polyacrylate resin (particle size 0.5 mm), and the soil is compacted to a water-retaining layer thickness of 1.2 cm, wherein the amount of sodium polyacrylate resin is 1.5 wt% of the weight of the soil.

[0040] (3) Intelligent system deployment: bury soil moisture sensors (depth 5 cm, located in the nutrient layer), set irrigation threshold 12%.

[0041] 3. Monitoring results

[0042] Table 1

[0043] Example 2 Limestone slope drought resistance experiment (continuous drought stress)

[0044] The settings of the fixation layer, water-retaining layer, and sensor in this example are the same as in Example 1.

[0045] 1. Drought simulation design

[0046] An artificial rain shelter was built, and natural precipitation was stopped for 30 days. Environmental parameters: daily average temperature 32℃±3℃, air humidity <40%.

[0047] 2. Key operations

[0048] The nutrient layer composition is the same as in Example 1, and the thickness is increased to 6 cm in this example. Irrigation strategy: when the sensor detects a water content ≤13%, the drip irrigation system automatically starts (2L / m² each time). Microbial activity monitoring: sample and detect ATP content every 7 days (kit method, Promega ENLITEN®).

[0049] 3. Drought response data

[0050] Table 2

[0051] Example 3 Sandstone slope erosion resistance experiment (strong rainfall environment)

[0052] The settings of the nutrient layer and water-retaining layer in this example are the same as in Example 1.

[0053] 1. Simulate strong rainfall conditions

[0054] Artificial rainfall intensity: 80 mm / h (lasting 2 hours).

[0055] Slope parameters: 70° sandstone, surface fragmentation >30%.

[0056] 2. Strengthening anti-scour structures

[0057] Strengthening the anchor layer: Based on Example 1, the amylase concentration was increased to 15%, and a glass fiber mesh (pore size 2 cm) was added.

[0058] Anchoring depth: Drill a 25 cm hole and inject a cement-based anchor rod (8 mm in diameter).

[0059] Drainage design: A diversion trough is set at the foot of the slope to collect runoff.

[0060] 3. 48 hours after the fixing layer, nutrient layer and water retention layer were laid, a scouring test was conducted. The results are as follows:

[0061] Table 3

[0062] The specific operation of the traditional soil-importing method is as follows: 60% soil-importing and 40g / m grass seeds 2 , moss spores 60g / m 2 , adhesive 0.8% of the dry weight of the substrate, water retaining agent 1% of the dry weight of the substrate, add water to mix into slurry, and spray it onto the slope surface with high pressure using a hydraulic sprayer.

[0063] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for biomimetic regreening of drought-resistant rock slopes of mines by moss-microorganism synergistic nitrogen fixation, characterized in that: The following steps are involved: (1) Slope pretreatment: drilling anchor holes; (2) Layered construction: ① Fixation layer: A mixed slurry made from amylase and plant fibers is sprayed to form a mesh matrix with a thickness of 1-2 cm. The specific preparation process of the mixed slurry is as follows: a. 4-6 wt% plant fibers are added to water and stirred to form a suspension; b. 8-12 wt% starch is mixed with water, heated to 60-70°C, 12-15 wt% amylase is added, stirred for at least 20 minutes, and heated to 90°C to form a gelatinized starch solution; c. Slowly add the plant fiber suspension to the gelatinized starch solution and stir to obtain a mixed slurry, wherein the dry weight ratio of the plant fiber to the amylase is 100:1.8~2.5; ② Nutrient layer: A mixture of a composite bacterial agent and slow-release fertilizer was sprayed to a thickness of 4 cm. The mixture was prepared as follows: a. 60 wt% of Physcomitrium patens spores, 25 wt% of Nostoc commune, and 15 wt% of Pseudomonas fluorescens were mixed with soluble starch and dried to produce spore powder, which was then mixed to produce a mixed bacterial agent. b. The slow-release fertilizer particles were coated with β-cyclodextrin to form an inner slow-release film, and a gelatin-polyvinyl alcohol cross-linked film was sprayed on the outer layer to control nutrient release. The coating layer accounted for 2-3% of the fertilizer weight and had a thickness of 50-100 μm. c. Dry mix the mixed bacteria: fertilizer at a mass ratio of 1:4-1:6, spray guar gum solution for bonding, and add 0.1-0.5% xanthan gum to enhance suspension; the fertilizer is ; ③ Water retention layer: Spread sodium polyacrylate resin with a particle size of 1-0.5mm, cover the soil and compact it until the water retention layer thickness is 1-1.5cm. The amount of sodium polyacrylate resin used is 2-1.5wt% of the soil weight.

2. The method for drought-resistant mine rock slopes using moss and microorganisms for nitrogen fixation and biomimetic greening according to claim 1, characterized in that: In step (1), the hole diameter is 3 cm, the depth is 20 cm, the hole spacing is 30×30 cm, and the holes are arranged in a plum blossom shape.

3. The method for drought-resistant mine rock slopes using moss and microorganisms for nitrogen fixation and biomimetic greening according to claim 2, characterized in that: The plant fiber in step (2) is bamboo fiber.

4. The method for drought-resistant mine rock slopes using moss and microorganisms for nitrogen fixation and biomimetic greening according to claim 3, characterized in that: In step ①, the amount of plant fiber used is 5 wt %; the amount of starch used is 10 wt %.

5. The method for drought-resistant mine rock slope biomimetic regreening by moss-microorganism synergistic nitrogen fixation according to claim 4, characterized in that: In the step ①, starch and water are mixed and heated to 65°C.

6. The method for drought-resistant mine rock slope biomimetic regreening by moss-microorganism synergistic nitrogen fixation according to claim 5, characterized in that: In step ①, the dry weight ratio of plant fiber to amylase is 100:

2.

7. The method for drought-resistant mine rock slopes using moss and microorganisms for nitrogen fixation and biomimetic greening according to claim 6, characterized in that: In the step ②, the mixture ratio of bacterial agent to fertilizer is 1:

5.

8. The method for drought-resistant rock slope restoration by moss and microorganisms through coordinated nitrogen fixation and biomimetic greening of mines according to any one of claims 1 to 7, characterized in that: The method further includes step (3) of burying a soil moisture sensor in the nutrient layer and setting the irrigation threshold to 12%.

9. Use of the method according to any one of claims 1 to 7 in ecological restoration of rock slopes.

10. A drought-resistant moss-microorganism synergistic nitrogen fixation biomimetic greening system for rocky slopes in mines, characterized by: The invention comprises a microbial composite unit, a hierarchical structure unit, and an intelligent monitoring unit; the microbial composite unit is composed of the spores of Physcomitrium patens, Nostoc commune, and Pseudomonas fluorescens in claim 1; the hierarchical structure unit is composed of the fixation layer, nutrient layer, and water retention layer in claim 1 from bottom to top; the intelligent monitoring unit comprises a soil moisture sensor, a microbial activity detection module, and an Internet of Things controller.

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