Water-retention drought-enduring straw fiber composite material for desert control and ecological restoration and preparation method of water-retention drought-enduring straw fiber composite material

Abstract

The invention relates to the technical field of ecological restoration materials, and discloses a water-retention and drought-enduring straw fiber composite material for desert control and ecological restoration and a preparation method of the water-retention and drought-enduring straw fiber composite material. Comprising 40-70 parts of plant fibers, 3-15 parts of super absorbent resin, 2-10 parts of decomposed organic matters, 10-15 parts of fly ash, 12-18 parts of coal gangue powder, 2-8 parts of an organic binder, 5-15 parts of sludge, 2-10 parts of a nutritional agent and 1-5 parts of a microbial agent. The fertilizer is scientific in component matching and remarkable in synergistic effect, can efficiently retain and lock water, slowly release water and nutrients, improve the sandy soil structure and promote plant root growth, can achieve resource utilization of waste such as straw and fly ash, has the advantages of being environmentally friendly, low in cost and adaptive to the desert environment, and has a wide application prospect. The vegetation survival rate and the ecological restoration efficiency in the desert area can be quickly improved.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration materials technology, and more specifically, to a water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration, and its preparation method. Background Technology

[0002] Desertification is one of the major ecological and environmental problems facing the world. Its spread not only leads to a decline in land productivity and a reduction in biodiversity, but also triggers extreme weather events such as sandstorms, seriously threatening regional ecological security and human survival and development. Currently, the core challenges of desertification control and ecological restoration lie in three major problems: water scarcity, poor soil structure, and rapid nutrient loss. Existing restoration technologies and materials still have many shortcomings, making it difficult to achieve efficient and long-term ecological restoration goals.

[0003] In terms of water retention, desert regions experience scarce annual rainfall and high evaporation rates, resulting in extremely poor soil water retention capacity. Limited rainfall or irrigation water is easily lost through rapid infiltration or evaporation, leading to low seed germination rates and difficulty in seedling survival. Traditional water-retaining materials, such as simple superabsorbent polymers, while possessing some water absorption capacity, suffer from poor soil bonding, water release rates that are difficult to match plant needs, and susceptibility to wind and sand migration. Furthermore, they lack the ability to improve soil structure and cannot fundamentally solve the problem of low water use efficiency.

[0004] In terms of soil structure improvement, desert soils are mainly composed of loose sand particles, lacking aggregate structure, and have weak resistance to wind and water erosion. Furthermore, the soil organic matter content is extremely low (usually below 0.5%), exhibiting characteristics of being barren, dry, and loose. Among existing remediation materials, inorganic fillers (such as sand, gravel, and fly ash) can improve soil stability, but lack the synergistic effect of organic components, making it difficult to improve soil fertility. Meanwhile, purely organic materials (such as straw and well-rotted organic fertilizer) suffer from poor formability and weak resistance to wind erosion, making it impossible for them to remain on the desert surface for extended periods and exert their effects.

[0005] In terms of nutrient supply, desert soils are nutrient-poor and prone to leaching and loss. Conventional fertilizers tend to volatilize quickly or seep into the soil with water after application, resulting in low nutrient utilization (usually less than 30%) and the potential for secondary soil salinization. Existing slow-release fertilizers are mostly designed for farmland and are not adapted to the strong evaporation and seepage characteristics of the desert environment. Their slow-release cycle does not match the needs of plant growth, and they lack synergy with water retention and soil improvement functions, making it difficult to support the entire growth cycle of plants from seedlings to mature plants.

[0006] In addition, existing desert restoration materials also suffer from problems such as resource waste and insufficient environmental protection: some materials rely on non-renewable resources for preparation, resulting in high costs; some chemically synthesized materials have poor degradability, and long-term use may cause soil pollution; at the same time, a large amount of straw, industrial waste (such as fly ash and coal gangue), and sewage treatment plant sludge generated in agricultural production have not been fully utilized, which wastes resources and pollutes the environment.

[0007] Therefore, it is of great practical significance to provide a composite remediation material that combines efficient water retention, soil structure improvement, long-term nutrient supply, and the ability to achieve waste resource utilization and environmental protection at low cost. Summary of the Invention

[0008] In view of this, the present invention proposes a water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration, aiming to solve at least one of the current background technical problems.

[0009] This invention proposes a water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration, comprising the following components in parts by weight: Plant fiber 40-70 parts, super absorbent resin 3-15 parts, decomposed organic matter 2-10 parts, fly ash 10-15 parts, coal gangue powder 12-18 parts, organic binder 2-8 parts, silt 5-15 parts, nutrient agent 2-10 parts, microbial agent 1-5 parts.

[0010] Preferably, the plant fiber is straw fiber; the superabsorbent resin is an environmentally friendly polyacrylate resin, which is a modified starch-grafted polyacrylate resin or a cellulose-grafted polyacrylate resin.

[0011] Preferably, the composted organic matter is obtained by mixing composted straw powder and composted biogas residue, wherein the mass ratio of composted straw powder to composted biogas residue is 1:1.

[0012] Preferably, the organic binder is one or more of polyvinyl alcohol and lignin sulfonate.

[0013] Preferably, the nutrient is obtained by mixing slow-release compound fertilizer, humic acid and phosphogypsum, wherein the mass ratio of the slow-release compound fertilizer, humic acid and phosphogypsum is 1-2:1-2:1-2.

[0014] Preferably, the microbial agent is obtained by combining drought-resistant and growth-promoting rhizobia, phosphorus- and potassium-solubilizing bacteria and photosynthetic bacteria, and the mass ratio of the drought-resistant and growth-promoting rhizobia, phosphorus- and potassium-solubilizing bacteria and photosynthetic bacteria is 1:1:1 to 2:1:1.

[0015] This invention also provides a method for preparing the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration as described in the above technical solution, comprising the following steps: Plant fiber, fly ash, coal gangue powder and sludge are pretreated to obtain a ready-to-use mixture; The prepared mixture is mixed with sludge, decomposed organic matter and nutrients to obtain a basic mixture. The microbial agent is prepared into a microbial agent solution, mixed with the base mixture, and then the organic binder and super absorbent resin are added after stirring. The mixture is heated and stirred to obtain the mixture to be molded. The mixture to be formed is pressed into granular or sheet material, and then cooled and dried to obtain the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration.

[0016] Preferably, the pretreatment specifically involves: crushing plant fibers to 1-5 mm, drying fly ash and coal gangue powder to a moisture content of ≤5%, and drying sludge and then crushing it to pass through an 80-mesh sieve.

[0017] Preferably, the heating and stirring specifically involves heating to 40-60°C and stirring for 20-40 minutes.

[0018] This invention also provides an application of a water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration, wherein the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration is any of the materials described in the above technical solutions.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The components of this invention are scientifically formulated and have significant synergistic effects. They can efficiently retain and lock in water, slowly release moisture and nutrients, improve the structure of sandy soil, promote plant root growth, and realize the resource utilization of waste such as straw and fly ash. It has the advantages of being environmentally friendly, low-cost, and adaptable to desert environments, and can rapidly improve the survival rate of vegetation and the efficiency of ecological restoration in desert areas. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0021] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0025] This invention provides a water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration, comprising the following components in parts by weight: Plant fiber 40-70 parts, super absorbent resin 3-15 parts, decomposed organic matter 2-10 parts, fly ash 10-15 parts, coal gangue powder 12-18 parts, organic binder 2-8 parts, silt 5-15 parts, nutrient agent 2-10 parts, microbial agent 1-5 parts.

[0026] Fly ash, as an inorganic filler, optimizes the particle size distribution of composite materials and improves the density and mechanical stability of molded materials; it contains mineral elements such as silicon, aluminum, and iron, which can serve as a source of soil minerals and improve the mineral deficiency of desert soils; its porous structure can help store water and adsorb small amounts of harmful substances in the soil, thus purifying the soil environment.

[0027] Coal gangue powder provides a hard inorganic skeleton, enhancing the wear resistance and wind erosion resistance of composite materials and extending their service life in desert environments. It is rich in silica, alumina and other components, which can react chemically with binders to improve the bonding strength of the materials. Granular coal gangue powder can fill the internal voids of composite materials, adjust the porosity of the materials, and balance the needs of water retention and air permeability.

[0028] Silt is rich in organic matter, nitrogen, phosphorus, potassium, and trace elements, making it a natural source of nutrients and reducing the amount of nutrient agents needed. Its viscous properties also help binders work, improving the molding effect and structural stability of materials. This allows for the resource utilization of solid waste such as river silt and sewage treatment plant sludge, reducing environmental pollution. Preferably, the silt used in this invention is river silt or sewage treatment plant sludge, which is dewatered and composted before use. Its organic matter content is ≥25%, and its heavy metal content meets the screening value requirements in the "Soil Environmental Quality Standard for Agricultural Land Soil Pollution Risk Control" (GB 15618-2018).

[0029] In this invention, the plant fiber is straw fiber; the superabsorbent resin is an environmentally friendly polyacrylate resin, which is a modified starch-grafted polyacrylate resin or a cellulose-grafted polyacrylate resin.

[0030] This invention uses straw fiber as the plant fiber to construct a three-dimensional mesh support structure, providing a physical skeleton for the composite material and improving the structural stability and porosity of the material after molding. It also enhances the material's ability to intertwine and entangle with sand and soil, promoting sand and soil aggregation and reducing wind and water erosion damage to the surface. Furthermore, the plant fiber itself can slowly degrade, releasing a small amount of organic matter during degradation, continuously improving the soil's aggregate structure. In addition, it can synergistically work with binders to improve the mechanical properties of the composite material.

[0031] This invention uses an environmentally friendly superabsorbent polymer (SAP) resin, specifically a modified starch-grafted SAP resin or a cellulose-grafted SAP resin. Specifically, the SAP resin possesses superior water absorption capabilities, rapidly absorbing rainwater, irrigation water, or moisture from the air and storing it within its molecular network. Triggered by changes in environmental humidity, it slowly releases the stored moisture, continuously supplying water to plant roots. The environmentally friendly resin leaves no heavy metal residues, and its degradation products are harmless to soil and plants, meeting the requirements for ecological restoration. This invention does not limit the specific type of modified starch-grafted SAP resin used for environmental protection; any resin well-known to those skilled in the art can be used. In the embodiments of this invention, starch-grafted sodium polyacrylate resin and carboxymethyl cellulose-grafted polyacrylate resin are used.

[0032] In this invention, the decomposed organic matter is obtained by mixing decomposed straw powder and decomposed biogas residue, wherein the mass ratio of decomposed straw powder to decomposed biogas residue is 1:1.

[0033] This invention utilizes well-rotted organic matter to provide abundant humus, amino acids, and other organic nutrients, directly supplementing plant growth with nutrients; it improves soil colloidal structure, enhances soil fertility and water retention capacity, and alleviates the problems of barren, dry, and loose desert soils; it provides carbon and nitrogen sources and other nutrient substrates for microbial agents, promoting the reproduction of beneficial microorganisms.

[0034] In this invention, the organic binder is one or more of polyvinyl alcohol and lignin sulfonate. This invention utilizes the organic binder to firmly bond plant fibers, inorganic fillers, organic matter, and other components together, achieving material molding, improving the interfacial bonding performance of the material, and enhancing its overall integrity and fracture resistance. Natural binders such as lignin sulfonate are biodegradable and can provide a small amount of organic nutrients to the soil. Polyvinyl alcohol is environmentally friendly and non-toxic, and will not harm the ecological environment.

[0035] In this invention, the nutrient agent is obtained by mixing slow-release compound fertilizer, humic acid, and phosphogypsum, with a mass ratio of 1-2:1-2:1-2. The slow-release compound fertilizer in the nutrient agent slowly releases nitrogen, phosphorus, and potassium, meeting the nutrient requirements of plants at different growth stages. Humic acid significantly improves soil fertility, promotes nutrient absorption and utilization by plant roots, and enhances plant resistance. Phosphogypsum provides calcium and sulfur, improves soil pH, and promotes plant cell wall development and photosynthesis.

[0036] Preferably, the slow-release compound fertilizer used in this invention has a total nutrient content (N+P2O5+K2O) ≥40% and a slow-release period of 3-6 months.

[0037] In this invention, the microbial inoculant is obtained by combining drought-resistant and growth-promoting rhizobia, phosphorus- and potassium-solubilizing bacteria, and photosynthetic bacteria, wherein the mass ratio of the drought-resistant and growth-promoting rhizobia, phosphorus- and potassium-solubilizing bacteria, and photosynthetic bacteria is 1:1:1 to 2:1:1. Preferably, the effective viable count of the drought-resistant and growth-promoting rhizobia should be ≥2.0 × 10⁻⁶. 9 The effective viable count of the phosphorus- and potassium-solubilizing bacteria should be ≥1.5 × 10⁻⁶ CFU / g. 9 The effective viable count of the photosynthetic bacteria should be ≥1.0 × 10⁻⁶ CFU / g. 9 CFU / g.

[0038] Specifically, drought-resistant and growth-promoting rhizobia secrete drought-resistant active substances, promote plant root growth, and enhance the plant's own drought resistance; phosphorus- and potassium-solubilizing bacteria convert phosphorus and potassium elements in the soil that are difficult for plants to absorb into soluble forms, thereby improving the soil's nutrient supply capacity; and photosynthetic bacteria use light energy to synthesize organic matter, providing plants with additional nutrients while inhibiting the reproduction of harmful microorganisms in the soil and improving the soil's micro-ecological environment.

[0039] This invention also provides a method for preparing the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration as described in the above technical solution, comprising the following steps: Plant fiber, fly ash, coal gangue powder and sludge are pretreated to obtain a ready-to-use mixture; The prepared mixture is mixed with sludge, decomposed organic matter and nutrients to obtain a basic mixture. The microbial agent is prepared into a microbial agent solution, mixed with the base mixture, and then the organic binder and super absorbent resin are added after stirring. The mixture is heated and stirred to obtain the mixture to be molded. The mixture to be formed is pressed into granular or sheet material, and then cooled and dried to obtain the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration.

[0040] The preferred preparation method is as follows: Plant fibers are crushed to a length of 1-5 mm; coal gangue powder and fly ash are dried to a moisture content of ≤5%; silt is dried, crushed, and then sieved through an 80-mesh sieve. According to the mass fractions, the pretreated plant fiber, coal gangue powder, fly ash, sludge, decomposed organic matter, and nutrients are mixed in sequence and stirred at room temperature for 15-30 minutes until they are evenly mixed to obtain the basic mixture. Dilute the microbial agent with deionized water 10-20 times to prepare a microbial agent solution, and spray it evenly into the base mixture. Continue stirring for 10-15 minutes. Then add the organic binder and super absorbent resin, heat to 40-60℃, and stir for 20-40 minutes until the materials are fully mixed. The above mixture is fed into a molding machine and pressed into granular material with a particle size of 2-5cm or sheet material with a thickness of 3-8cm under a pressure of 5-10MPa and a temperature of 60-80℃, and the pressure is maintained for 10-20 minutes. Finally, the molded material is naturally cooled to room temperature and then dried at low temperature (30-45℃, 2-4 hours) until the moisture content is ≤10%, thus obtaining a water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration.

[0041] This invention also provides an application of a water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration, wherein the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration is any of the materials described in the above technical solutions.

[0042] Example 1 (1) Prepare the composite material formula according to the mass parts: 55 parts of straw fiber, 8 parts of modified starch grafted polyacrylate resin, 6 parts of decomposed organic matter (obtained by mixing decomposed straw powder and decomposed biogas residue in a mass ratio of 1:1), 12 parts of fly ash, 15 parts of coal gangue powder, 5 parts of polyvinyl alcohol, 10 parts of river silt, 6 parts of nutrient agent (obtained by mixing slow-release compound fertilizer, humic acid and phosphogypsum in a mass ratio of 1:1:1), and 3 parts of microbial agent (obtained by mixing drought-resistant and growth-promoting rhizobium, phosphorus-solubilizing and potassium-solubilizing bacteria and photosynthetic bacteria in a mass ratio of 1:1:1).

[0043] (2) Raw material pretreatment: The straw fiber is crushed to a length of 2-3 mm by a crusher to ensure that the fiber is evenly dispersed; fly ash and coal gangue powder are placed in a drying oven at 105℃ and dried for 3 hours until the moisture content is ≤5% to remove excess moisture and avoid affecting the molding; the river silt is naturally dried for 72 hours, crushed and passed through an 80-mesh sieve to remove stones, impurities and other large particles for later use.

[0044] (3) Mixing and batching: According to the above mass proportions, add the pretreated straw fiber, fly ash, coal gangue powder, silt, decomposed organic matter and nutrients into a twin-shaft mixer and stir at 30 r / min for 25 minutes at room temperature until all components are mixed evenly to form a basic mixture.

[0045] (4) Addition of microbial agent and binder: Dilute the microbial agent with deionized water 15 times to prepare a uniform microbial agent solution. Spray it evenly into the base mixture through a spraying device and continue stirring for 12 minutes to ensure that the microbial agent and the mixture are in full contact. Then add polyvinyl alcohol and modified starch-grafted polyacrylate resin, raise the temperature of the mixer to 50°C, and keep the speed constant while stirring for 30 minutes to fully integrate the materials and obtain the mixture to be formed.

[0046] (5) Molding process: The mixture to be molded is fed into a hydraulic molding machine, the pressure is set to 8MPa and the temperature to 70℃, and it is pressed into granular material with a particle size of 3-4cm. The pressure is held for 15 minutes to enhance the structural stability of the material.

[0047] (6) Post-processing: Take out the granular material after molding, let it cool naturally to room temperature, and then put it into a 40℃ low temperature drying oven to dry for 3 hours until the moisture content is ≤10%, thus obtaining the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration.

[0048] Example 2 (1) Prepare the raw materials for the composite material formula according to the mass parts: 65 parts of straw fiber, 12 parts of cellulose grafted polyacrylate resin, 8 parts of decomposed organic matter (obtained by mixing decomposed straw powder and decomposed biogas residue in a mass ratio of 1:1), 14 parts of fly ash, 16 parts of coal gangue powder, 6 parts of lignin sulfonate, 12 parts of sewage treatment plant sludge, 8 parts of nutrient agent (obtained by mixing slow-release compound fertilizer, humic acid and phosphogypsum in a mass ratio of 2:1:1), and 4 parts of microbial agent (obtained by mixing drought-resistant and growth-promoting rhizobium, phosphorus-solubilizing and potassium-solubilizing bacteria and photosynthetic bacteria in a mass ratio of 1:1:2).

[0049] (2) Raw material pretreatment: crush straw fibers to a length of 3-5 mm to ensure the interweaving ability between fibers; dry fly ash and coal gangue powder in a 110℃ drying oven for 2.5 hours until the moisture content is ≤5%; dewater the sewage treatment plant sludge by plate and frame filter press, air dry for 48 hours, crush it and pass it through an 80-mesh sieve to remove impurities, and set it aside for use.

[0050] (3) Mixing and batching: According to the set mass proportions, add the pretreated straw fiber, fly ash, coal gangue powder, silt, decomposed organic matter and nutrients into the plow-type mixer, stir at 40 r / min for 30 minutes at room temperature to ensure that each component is evenly dispersed and obtain the basic mixture.

[0051] (4) Addition of microbial agent and binder: Dilute the microbial agent with deionized water 20 times to prepare a microbial agent solution, spray it evenly into the base mixture, and continue to stir for 15 minutes; then add lignin sulfonate and cellulose grafted polyacrylate resin, raise the temperature of the mixer to 55°C, stir for 35 minutes to allow the binder to play its full role and the materials to be completely integrated to obtain the mixture to be formed.

[0052] (5) Molding process: The mixture to be molded is fed into a roll forming machine, the pressure is set to 10MPa and the temperature to 75℃, and it is pressed into a sheet material with a thickness of 5-6cm. The pressure is held for 20 minutes to improve the density of the material.

[0053] (6) Post-processing: After the sheet material is formed, it is naturally cooled to room temperature and then placed in a 45℃ low temperature drying oven for 2.5 hours until the moisture content is ≤10%, thus obtaining the water-retaining and drought-resistant straw fiber composite material used for desert control and ecological restoration.

[0054] Performance testing 1. Water retention capacity test Water absorption ratio test: Take 50g of each material sample and place them in a 500ml beaker. Add 3000ml of deionized water (simulating freshwater rainfall) and soak at room temperature (25℃) for 24 hours. Stir once every 6 hours during the period to ensure full water absorption. Filter out excess water using an 80-mesh filter, let stand for 10 minutes, weigh, and calculate the water absorption ratio = (total mass after water absorption - initial mass of sample) / initial mass of sample.

[0055] Water retention rate test: The water-absorbing sample was placed in a constant temperature and humidity chamber (temperature 30℃, humidity 40%, simulating the daytime environment of the desert), and weighed on the 7th, 15th and 30th days respectively. The water retention rate was calculated as follows: (sample mass on the test day - initial sample mass) / (mass after 24 hours of water absorption - initial sample mass) × 100%.

[0056] Salt tolerance and water retention test: Prepare a 0.5% NaCl solution (simulating the moisture content of saline soil in the desert), repeat the above water absorption ratio and water retention rate test, and record the water absorption ratio after 24 hours and the water retention rate after 15 days.

[0057] The test results are shown in Table 1. Table 1. Results of Water Retention Capacity Test

[0058] As shown in Table 1, the composite materials of Examples 1 and 2 have excellent water absorption, water retention and salt resistance properties. The fresh water absorption rate is 59.6-65.0 g / g in 24 hours and the fresh water retention rate is 42.5-45.8% in 30 days. They maintain stable water retention under salt-resistant conditions and can effectively adapt to the high evaporation and saline soil environment of the desert, meeting the long-term water needs of plants.

[0059] 2. Soil amendment performance test Original desert sand (collected from the edge of the Tengger Desert, with an organic matter content of 0.35% and a bulk density of 1.65 g / cm³) was selected. 3 The mixture (pH value 8.6, granular structure (>0.25mm) 12.1%) was mixed at a mass ratio of "sand:material = 10:1" and placed in a 20cm×20cm×20cm test pot, with 3 replicates per group; Placed in an open-air environment (natural light and rainfall, simulating desert conditions), with small amounts of water added periodically to maintain the initial soil moisture content at 10%, samples were taken after 30 days. Organic matter content was determined by potassium dichromate titration method, bulk density was determined by ring cutter method, pH value was determined by pH meter (soil-water ratio 1:2.5), and the proportion of aggregate structure (>0.25mm) was determined by wet sieving method.

[0060] The test results are shown in Table 2. Table 2. Results of Soil Amendment Performance Tests

[0061] As shown in Table 2, the composite material can significantly improve the properties of desert soil, increasing the soil organic matter content to 1.82-1.95% and reducing the bulk density to 1.38-1.42 g / cm³. 3 The pH value tends to be neutral, and the proportion of aggregate structure increases to 38.6-41.2%, effectively solving the problems of "lean, dry and loose" desert soil and creating a good soil environment for plant growth.

[0062] 3. Mechanical and wind erosion resistance tests Compressive strength test: The granular sample (Example 1) after molding was cut into 5cm×5cm×5cm cubes, and the sheet sample (Example 2) was cut into 5cm×5cm×5cm cubes. The control group was mixed and pressed into samples of the same size. The compressive strength was tested using a universal testing machine (loading rate 2 mm / min), with 5 samples per group and the average value was taken.

[0063] Wind erosion resistance test: Each material sample was laid flat on the wind tunnel test bench (with a thickness of 5cm), and the wind speed was set to 5m / s (simulating the average annual wind speed in the desert) and blown continuously for 24 hours; Weigh the sample before and after air blowing, and calculate the wind erosion wear rate = (mass before air blowing - mass after air blowing) / mass before air blowing × 100%.

[0064] The test results are shown in Table 3. Table 3. Test Results of Mechanical and Wind Erosion Resistance

[0065] As shown in Table 3, the compressive strength of the composite materials in Examples 1 and 2 reaches 1.25-1.42 MPa, and the 24-hour wind erosion abrasion rate is only 2.5-3.8%. They have outstanding mechanical stability and wind erosion resistance, and can remain on the desert surface for a long time to avoid being eroded and lost by strong winds, thus ensuring the long-term effectiveness of the repair.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration, characterized in that, The components include the following parts by mass: Plant fiber 40-70 parts, super absorbent resin 3-15 parts, decomposed organic matter 2-10 parts, fly ash 10-15 parts, coal gangue powder 12-18 parts, organic binder 2-8 parts, silt 5-15 parts, nutrient agent 2-10 parts, microbial agent 1-5 parts.

2. The water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration according to claim 1, characterized in that, The plant fiber is straw fiber; the superabsorbent resin is an environmentally friendly polyacrylate resin, which is a modified starch-grafted polyacrylate resin or a cellulose-grafted polyacrylate resin.

3. The water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration according to claim 1, characterized in that, The decomposed organic matter is obtained by mixing decomposed straw powder and decomposed biogas residue, wherein the mass ratio of decomposed straw powder to decomposed biogas residue is 1:

1.

4. The water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration according to claim 1, characterized in that, The organic binder is one or more of polyvinyl alcohol and lignin sulfonate.

5. The water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration according to claim 1, characterized in that, The nutrient is obtained by mixing slow-release compound fertilizer, humic acid and phosphogypsum, and the mass ratio of the slow-release compound fertilizer, humic acid and phosphogypsum is 1-2:1-2:1-2.

6. The water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration according to claim 1, characterized in that, The microbial agent is obtained by combining drought-resistant and growth-promoting rhizobia, phosphorus- and potassium-solubilizing bacteria and photosynthetic bacteria, and the mass ratio of the drought-resistant and growth-promoting rhizobia, phosphorus- and potassium-solubilizing bacteria and photosynthetic bacteria is 1:1:1-2:1:

1.

7. A method for preparing a water-retaining and drought-resistant straw fiber composite material for desertification control and ecological restoration as described in any one of claims 1-6, characterized in that, Includes the following steps: Plant fiber, fly ash, coal gangue powder and sludge are pretreated to obtain a ready-to-use mixture; The prepared mixture is mixed with sludge, decomposed organic matter and nutrients to obtain a basic mixture. The microbial agent is prepared into a microbial agent solution, mixed with the base mixture, and then the organic binder and super absorbent resin are added after stirring. The mixture is heated and stirred to obtain the mixture to be molded. The mixture to be formed is pressed into granular or sheet material, and then cooled and dried to obtain the water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration.

8. The preparation method according to claim 7, characterized in that, The pretreatment specifically involves: crushing plant fibers to 1-5mm, drying fly ash and coal gangue powder to a moisture content of ≤5%, and drying sludge and then crushing it to pass through an 80-mesh sieve.

9. The preparation method according to claim 7, characterized in that, The heating and stirring process specifically involves heating to 40-60℃ and stirring for 20-40 minutes.

10. A water-retaining and drought-resistant straw fiber composite material for desert control and ecological restoration, characterized in that, The water-retaining and drought-resistant straw fiber composite material used for desertification control and ecological restoration is the material described in any one of claims 1-6.

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