Fungus mycelium enhanced salix mongolica-based degradable sand barrier and preparation method thereof

Abstract

The invention discloses a fungal mycelium enhanced salix mongolica-based degradable sand barrier and a preparation method thereof, and relates to the field of salix mongolica-based degradable sand barriers, according to the fungal mycelium enhanced salix mongolica-based degradable sand barrier and the preparation method thereof, a three-dimensional network is formed by utilizing fungal mycelium through a biological enhancement technology, and the three-dimensional network penetrates into fibers, so that the sand barrier is formed; and through the synergistic effect with the nano coating, the reduction rate of the wind speed and the reduction amount of the sediment transport rate after barrier are improved by 20%-25% and 25%-29% respectively compared with the prior art. In the aspect of durability, chemical fibers are replaced by bio-based fibers, micro-plastic pollution is avoided, meanwhile, the interface bonding strength of mycelia is improved by 5 times compared with existing physical weaving, the grid integrity rate within 2-3 years is as high as 90% or above, the strength retention rate of a mycelia enhancement layer is also very considerable, ultraviolet aging and wind erosion are effectively resisted, the service life of the sand barrier is greatly prolonged, and the sand barrier is suitable for large-scale popularization and application. And a more durable and reliable protective barrier is provided for desertification control.

Description

Technical Field

[0001] This invention relates to Salix psammophila-based biodegradable sand barrier technology, specifically to a fungal mycelium-enhanced Salix psammophila-based biodegradable sand barrier and its preparation method. Background Technology

[0002] Desertification has become a global ecological challenge, posing a serious threat to the ecological environment, agricultural production, and human survival and development. In the process of desertification control, sand barrier technology plays an indispensable role as a key measure. By reducing wind speed and intercepting sand particles in windblown sand, sand barriers effectively reduce wind erosion of the land surface, creating favorable conditions for vegetation restoration, thereby achieving the goals of windbreak and sand fixation and improving the desert ecological environment.

[0003] Traditional sand barrier techniques primarily employ physical weaving, using natural materials such as willow branches as a base, and manually weaving them into square or other shapes. For example, untreated willow branches (5-15mm in diameter, 50-100cm in length) are directly cut to fixed lengths and woven into square sand barriers, secured with wire at intersections. Some areas are supplemented with polypropylene (PP) chemical fiber mesh (10cm x 10cm, 2mm wire diameter) to improve tear resistance. However, this traditional sand barrier technique has many significant drawbacks.

[0004] In terms of durability, the untreated branches of *Salix psammophila* have an intact lignin structure but a smooth surface, making it difficult for mycelium or microorganisms to adhere. In the harsh natural environment of the desert, *Salix psammophila* branches are highly susceptible to UV aging, typically showing surface cracking after 3-6 months. Simultaneously, wind erosion is severe, with a grid breakage rate as high as 40% within one year. While PP fiber mesh used to enhance tear resistance provides some reinforcement, long-term exposure to UV radiation (strength decreases by 50% after 6-12 months) and high temperatures (sand surface temperatures can reach 60℃) easily leads to embrittlement, and residual fragments can pollute the soil.

[0005] In terms of ecological compatibility, traditional sand barriers lack the function of promoting plant growth. Due to poor water retention, the survival rate of sand willow seedlings within the grid is only 60%, and the root growth is 30% lower than that of the embodiment of this invention. In addition, the degradation cycle of PP fiber mesh is as long as 50 years or more, which not only hinders the expansion of plant roots, but also its degradation products (microplastics) are toxic to soil microorganisms, seriously affecting the restoration and balance of the desert ecosystem.

[0006] The limited functionality of traditional sand barrier technology is also a major drawback. It only possesses the single function of blocking sand and performs poorly in terms of wind erosion resistance, water retention, and UV resistance. After continuous operation at a wind speed of 15 m / s for 3 hours, the surface wind erosion can reach 8 g / m² (≤3 g / m² in this invention); the water retention rate is only 80% (≥200% in this invention), requiring frequent artificial water replenishment; and the PP fiber mesh without nanomaterial protection retains only 65% ​​of its strength after 200 hours of UV irradiation (95% retention rate of the nano-titanium dioxide coating in this invention).

[0007] Uncontrollable degradation cycles are another problem faced by traditional sand barrier technology. The degradation cycle of sand willow branches is greatly affected by environmental humidity, taking 3-5 years in arid areas and only 1-2 years in semi-arid areas, which cannot match the pace of vegetation restoration; while PP fiber netting cannot be degraded and requires manual recycling, which is not only costly but also has a recycling rate of less than 50%, further aggravating the environmental burden.

[0008] In summary, existing traditional sand barrier technologies suffer from serious shortcomings in terms of durability, ecological compatibility, functional diversity, and controllable degradation cycles, making it difficult to meet the increasingly severe demands of desertification control. Therefore, developing a novel sand barrier technology with high durability, good ecological compatibility, multiple functions, and a controllable degradation cycle has become a critical issue urgently needing to be addressed in the field of desertification control. Summary of the Invention

[0009] The purpose of this invention is to provide a fungal mycelium-enhanced degradable sand barrier based on Salix psammophila and its preparation method, so as to overcome the shortcomings of the prior art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a fungal mycelium-reinforced degradable sand barrier based on Salix psammophila, made from the following raw materials in the following mass percentages:

[0011] Substrate: 60%-75% of sand willow fiber particles (particle size 0.3-2.5mm), pretreated with steam explosion (pressure 1.5-2.5MPa, time 5-15 minutes) to destroy the lignin structure and improve the surface roughness;

[0012] Biological binder: Fungal mycelial network (5%-18% dry weight), obtained through solid-state fermentation culture, in which the mycelium penetrates deep into the fiber to form a three-dimensional interwoven structure;

[0013] Reinforcing fiber: It is made of polylactic acid (PLA) fiber (3-10mm in length) and bamboo fiber (5-15mm in length) mixed in a mass ratio of 2:1, with an addition amount of 8%-15%;

[0014] Functional additives include nano silica (particle size 20-50nm, addition amount 0.5%-2%, used for UV protection), humic acid (addition amount 1%-5%, used for water retention and root promotion) and chitosan (addition amount 0.1%-1%, used to induce mycelium to secrete extracellular polymers).

[0015] Furthermore, the fungal mycelium is at least one of the genera *Trichoderma* or *Phanerochaete chrysosporium*, and the solid-state fermentation conditions are as follows:

[0016] Matrix: Sand willow fiber granules and wheat bran are mixed at a mass ratio of 4:1;

[0017] Environment: Temperature 25-32℃, humidity 65%-85%, incubation time 7-21 days;

[0018] Inducer: Add chitosan or sodium lignin sulfonate at 0.1%-0.5% of the total matrix mass to promote the secretion of extracellular polymeric substances (EPS) by mycelium and enhance the interfacial bonding strength with fibers.

[0019] A method for preparing a fungal mycelium-enhanced, degradable sand barrier based on Salix psammophila includes the following steps:

[0020] Step 1: Substrate pretreatment: After crushing the sand willow branches, screen out the fiber particles with a particle size of 0.3-2.5mm, treat them with steam explosion (pressure 1.5-2.5MPa, time 5-15 minutes), soak them in 5% NaOH solution for 2 hours, wash them with water until neutral and dry them.

[0021] Step 2, Mycelial Culture: The pretreated fibers are mixed with a fungal spore suspension (concentration 1×10⁻⁶). 6 -1×10 8 Mix (CFU / mL) at a mass ratio of 100:0.5-100:2, pack into an air-permeable mold, and culture under the conditions described in claim 2 until the mycelium covers more than 90% of the substrate surface;

[0022] Step 3, Composite Molding: The reinforcing fibers, functional additives and mycelium-sand willow composite substrate are mixed and molded into sand barrier boards with a thickness of 1-5cm and a porosity of 25%-60% under a pressure of 10-30MPa and a temperature of 40-70℃.

[0023] Step 4, Post-processing: Cut the sand barrier into 1m×1m or 2m×2m sizes, and spray the surface with a biodegradable coating containing humic acid and nano titanium dioxide (particle size <100nm), with a coating thickness of 0.1-0.5mm.

[0024] Furthermore, during the molding process, biodegradable fiber ropes (made of polylactic acid fiber and flax fiber blend, with a diameter of 1-3 mm) are pre-embedded in the mold to enhance the tear resistance of the sand barrier, with a fiber rope spacing of 10-30 cm.

[0025] Furthermore, the degradation cycle of the sand barrier is achieved by adjusting the mycelium content and the proportion of functional additives:

[0026] Short-term degradation type (6-12 months): mycelium content 5%-8%, nano silica addition 0.5%-1%, humic acid addition 1%-2%;

[0027] Long-term degradable type (18-36 months): mycelium content 12%-18%, nano silica addition 1%-2%, humic acid addition 3%-5%.

[0028] Furthermore, the surface of the sand barrier is provided with a diamond-shaped or wavy textured structure with a groove depth of 0.5-2cm, which is used to intercept fine particulate matter (particle size <0.05mm) in the wind and sand flow, thereby improving the efficiency of windbreak and sand fixation.

[0029] Furthermore, the method of sand barrier and plant root system working together to fix sand is as follows: after the sand barrier is laid, at least one of sand willow, caragana or tamarisk is planted in the grid. The water retention performance of the sand barrier (water holding rate ≥200%) and the root-promoting effect of humic acid (root growth increases by 30%-50%) are used to form a composite sand-fixing system with the plant root system and mycelium network.

[0030] The application of a fungal mycelium-enhanced degradable sand barrier based on Salix psammophila in desertification control is applicable to the treatment of mobile dunes, semi-fixed dunes, or wind erosion pits. The laying methods include square, strip, or fish scale patterns, with a laying density of 150-600 grids per hectare. It is also used in conjunction with a micro-irrigation system to improve vegetation survival rate.

[0031] Compared with existing technologies, the fungal mycelium-enhanced Salix psammophila-based biodegradable sand barrier and its preparation method provided by the present invention have the following beneficial effects:

[0032] The fungal mycelium-reinforced biodegradable sand barrier provided by this invention exhibits outstanding windbreak and sand-fixing effects. Through bio-reinforcement technology, fungal mycelium forms a three-dimensional network that penetrates deep into the fiber interior, working synergistically with a nano-coating to increase the reduction in wind speed and sand transport rate behind the barrier by 20%-25% and 25%-29%, respectively, compared to existing technologies. In terms of durability, the bio-based fiber replaces chemical fiber, avoiding microplastic pollution. Simultaneously, the interfacial bonding strength of the mycelium is five times higher than existing physical weaving methods, with a grid integrity rate exceeding 90% within 2-3 years. The strength retention rate of the mycelium reinforcement layer is also considerable, effectively resisting UV aging and wind erosion, significantly extending the service life of the sand barrier, and providing a more durable and reliable protective barrier for desertification control.

[0033] This invention's sand barrier exhibits excellent ecological compatibility. The added root-promoting additives and water-retention function significantly increase the survival rate of *Salix psammophila* seedlings from 60% in existing technologies to 93%-97%, and increase root growth by 30%-50%. It forms a "biological-mechanical" composite sand-fixing system with the mycelial network, effectively promoting vegetation restoration. Furthermore, by adjusting the substrate pretreatment process and coating formula, the degradation cycle of the sand barrier can be precisely controlled within 6-36 months, perfectly matching the pace of vegetation restoration and avoiding the high costs and environmental pollution associated with manual recycling due to chemical residues in existing technologies. In addition, Examples 2 / 3 introduce additional functions such as antibacterial properties and intelligent humidity response to adapt to different desert environments, comprehensively improving the effectiveness and sustainability of desertification control. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0035] Figure 1 This is a flowchart of a method for preparing a fungal mycelium-enhanced, degradable sand barrier based on Salix psammophila according to the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] Example 1: Preparation of short-term degradable sand barriers

[0038] Step 1: Substrate pretreatment: After crushing the sand willow branches, screen out the fiber particles with a particle size of 1mm, steam explosion treatment at 2.0MPa pressure for 10 minutes, then soak in 5% NaOH solution for 2 hours, wash with water until neutral and dry.

[0039] Step 2, Mycelial Culture: Using *Trichoderma reesei* as the strain, pretreated fiber and wheat bran (mass ratio 4:1) were mixed, and 0.3% chitosan was added as an inducer. The mixture was then inoculated with a spore suspension (concentration 1×10⁻⁶). 7 After filling the mold with (CFU / mL), the mixture was cultured at 28℃ and 80% humidity for 14 days to form a composite substrate with a mycelial dry weight ratio of 8%.

[0040] Step 3, Composite Molding: The reinforcing fiber (PLA to bamboo fiber mass ratio 2:1, addition amount 10%) and functional additives (nano silica 0.8%, humic acid 1.5%, chitosan 0.5%) are mixed with the composite substrate and molded into a sand barrier board with a thickness of 2m×2m and 3cm under the conditions of 20MPa and 50℃.

[0041] Step 4, Post-treatment: After cutting, spray a coating containing 2% humic acid and 0.5% nano titanium dioxide. The degradation period is 10 months.

[0042] Tests have shown the following effects: a 55% reduction in wind speed after the barrier, and a 95% reduction in sand transport rate; a 90% grid integrity rate and an 85% retention rate of mycelial reinforcement layer strength within 2 years; a 93% survival rate for *Salix psammophila* seedlings; a 15cm thickness for the root and mycelial composite sand-fixing layer; precise control of the degradation cycle from 12 months (arid areas) to 36 months (humid areas); and resistance to wind erosion, water retention (200% water holding capacity), root promotion, and UV protection (nano-TiO2 coating).

[0043] Initial costs are comparable, but maintenance costs decrease by 70% over 5 years.

[0044] Example 2: Preparation of a long-term degradable sand barrier

[0045] Step 1, Substrate pretreatment: Same as in Example 1, but the steam explosion pressure is adjusted to 2.5 MPa and the time is 15 minutes;

[0046] Step 2, Mycelial Culture: Using white rot fungus (Phanerochaete chrysosporium) as the strain, the culture conditions are the same as in Example 1, but the inducing agent is changed to 0.5% sodium lignosulfonate to form a composite substrate with a mycelial dry weight ratio of 15%.

[0047] Step 3, Composite Molding: The amount of reinforcing fiber added is increased to 12%, and the functional additives are adjusted to 1.5% nano silica, 3% humic acid, and 0.8% chitosan. The molding pressure is 25MPa and the temperature is 60℃ to make a sand barrier with a thickness of 4cm.

[0048] Step 4, Post-treatment: After cutting, spray a coating containing 3% humic acid and 1% nano titanium dioxide. The degradation period is 24 months.

[0049] Tests have shown the following effects: wind speed reduction by 58% and sand transport rate reduction by 98%; grid integrity rate of 92% within 2 years and tear resistance of bio-based fibers increased by 3 times; survival rate of sand willow of 95%; sand fixation layer thickness of 18cm; two additional species of associated plants; degradation cycle of 18 months, synchronously matching the growth rhythm of vegetation; wind erosion resistance + water retention (250%) + root promotion + antibacterial (chitosan coating); initial cost is 10% higher, but maintenance cost is reduced by 80% after 5 years.

[0050] Example 3: Preparation of UV-resistant enhanced sand barrier

[0051] Step 1, Substrate pretreatment: Same as in Example 1, but the steam explosion pressure is adjusted to 2.5 MPa and the time is 15 minutes;

[0052] Step 2, Mycelial Culture: Using white rot fungus (Phanerochaete chrysosporium) as the strain, the culture conditions are the same as in Example 1, but the inducing agent is changed to 0.5% sodium lignosulfonate to form a composite substrate with a mycelial dry weight ratio of 15%.

[0053] Step 3, Composite Molding: The amount of reinforcing fiber added is increased to 12%, and the functional additives are adjusted to 2% nano titanium dioxide, 3% humic acid, and 0.8% chitosan. The molding pressure is 25MPa and the temperature is 60℃ to make a sand barrier with a thickness of 4cm.

[0054] Step 4, Post-treatment: After cutting, spray a coating containing 3% humic acid and 1% nano titanium dioxide. The degradation period is 24 months.

[0055] The test results show the following effects: wind speed reduction by 60% and sand transport rate reduction by 99%; grid integrity rate of 95% within 3 years; nano-coating anti-UV aging lifespan extended to 5 years; sand willow survival rate of 97%; sand fixation layer thickness of 20cm; soil microbial activity increased by 50%; degradation cycle of 24 months; degradation products promote soil aggregate structure formation; wind erosion resistance + water retention (300%) + root promotion + intelligent response humidity regulation; initial cost is 15% higher, but maintenance cost is reduced by 85% after 5 years. After 200 hours of UV irradiation (wavelength 365nm, intensity 50mW / cm²), the tensile strength retention rate of this sand barrier reaches 95%, significantly higher than the 82% without nano-titanium dioxide.

[0056] Comparison of existing technologies

[0057] 1. Technical Solution Description

[0058] (1) Material composition

[0059] Substrate: Untreated sand willow branches (5-15mm in diameter, 50-100cm in length), directly cut to a fixed length and woven into a grid-like sand barrier;

[0060] Adhesive: No biological adhesive is used; the structure is fixed solely by the physical action of the interlacing of the willow branches.

[0061] Reinforcing materials: Some areas are reinforced with polypropylene (PP) chemical fiber mesh (mesh size 10cm×10cm, filament diameter 2mm) to improve tear resistance;

[0062] Functional additives: No UV protection, water retention or root-promoting additives, relying solely on the inherent properties of Salix psammophila.

[0063] (2) Preparation method

[0064] Substrate treatment: After the sand willow branches are naturally dried, they are manually cut into uniform lengths without the need for crushing or pretreatment;

[0065] Sand barrier weaving: Weave sand willow branches into a square pattern (1m×1m) on the sandy surface, and fix the intersections with wire;

[0066] Chemical fiber reinforcement: PP fiber mesh is laid on the surface of the sand barrier and fixed to the sand with U-shaped nails;

[0067] Application: Directly laid on shifting sand dunes, without subsequent coating or functional treatment.

[0068] 2. Deficiencies in existing technology

[0069] (1) Insufficient durability

[0070] Untreated sand willow branches have an intact lignin structure but a smooth surface, making it difficult for mycelium or microorganisms to attach. They are susceptible to UV aging (surface cracking after 3-6 months) and wind erosion (grid damage rate reaches 40% within 1 year).

[0071] Although PP fiber mesh is tear-resistant, it is prone to embrittlement when exposed to ultraviolet rays (its strength decreases by 50% after 6-12 months) and high temperatures (the surface temperature of sandy land can reach 60℃) for a long time, and residual fragments pollute the soil.

[0072] (2) Poor ecological compatibility

[0073] Lacking plant growth promotion function: The sand barrier only plays a physical role in preventing sand from falling, and the survival rate of sand willow seedlings inside the grid is only 60% (due to poor water retention), and the root growth is 30% lower than that of the embodiment of the present invention;

[0074] Chemical fibers have a degradation cycle of more than 50 years, hindering the expansion of plant roots, and their degradation products (microplastics) are toxic to soil microorganisms.

[0075] (3) Single function

[0076] It does not integrate multiple functions such as UV protection, water retention, and wind erosion resistance.

[0077] Wind erosion resistance: After continuous action at a wind speed of 15m / s for 3 hours, the surface wind erosion amount reaches 8g / m² (≤3g / m² of this invention).

[0078] Water retention: The water retention rate is only 80% (≥200% in this invention), requiring frequent artificial water replenishment;

[0079] UV resistance: Without nanomaterial protection, the PP fiber mesh retains only 65% ​​of its strength after 200 hours of UV irradiation (the nano titanium dioxide coating of this invention retains 95%).

[0080] (4) The degradation cycle is uncontrollable.

[0081] The degradation cycle of sand willow branches is greatly affected by environmental humidity. In arid areas, the degradation time can be as long as 3-5 years, while in semi-arid areas it is only 1-2 years, which cannot match the pace of vegetation restoration.

[0082] PP fiber mesh is non-degradable and requires manual recycling (which is costly and has a recycling rate of less than 50%).

[0083] The effects of the fungal mycelium-enhanced degradable sand barrier based on Salix psammophila from Examples 1 to 3 and their preparation methods were compared with those of the control example, and the results are shown in the table below:

[0084] Comparison items Comparison Example Example 1 Example 2 Example 3 Windbreak and sand fixation effect The wind speed was reduced by 35% and the sand transport rate was reduced by 70% after the barrier was applied. The wind speed was reduced by 55% and the sand transport rate was reduced by 95% after the barrier was applied. The wind speed was reduced by 58% and the sand transport rate was reduced by 98% after the barrier was applied. The wind speed was reduced by 60% and the sediment transport rate was reduced by 99% after the barrier was removed. Durability Within one year, the grid breakage rate was 40%, and the strength of the PP fiber mesh decreased by 50% after 12 months. Within two years, the grid integrity rate was 90%, and the mycelial reinforcement layer strength retention rate was 85%. Within 2 years, the grid integrity rate reached 92%, and the tear resistance of the bio-based fiber increased by 3 times. Within 3 years, the grid integrity rate is 95%, and the nano-coating extends the UV aging resistance lifespan to 5 years. Ecological compatibility The survival rate of sand willow seedlings was 60%, root growth was 30% low, and residual microplastic pollution was observed. The survival rate of sand willow seedlings was 93%, and the thickness of the root and mycelium composite sand-fixing layer was 15cm. The survival rate of sand willows was 95%, the sand-fixing layer was 18cm thick, and the number of associated plant species increased by 2. The survival rate of sand willow was 97%, the sand-fixing layer was 20cm thick, and the activity of soil microorganisms increased by 50%. Degradation cycle Willow branches degrade in 1-5 years, while PP fiber mesh is non-degradable. Precise regulation of the degradation cycle from 12 months (arid areas) to 36 months (humid areas) The degradation cycle is 18 months, which is synchronized with the vegetation growth rhythm. The degradation cycle is 24 months, and the degradation products promote the formation of soil aggregates. Functionality Single sand-blocking function <![CDATA[Wind erosion resistance + water retention (water holding rate 200%) + root promotion + UV resistance (nano-TiO2 coating)]]> Wind erosion resistant + water retention (250%) + root promotion + antibacterial (chitosan coating) Wind erosion resistant + water retention (300%) + root promotion + intelligent response humidity regulation Cost-effectiveness Initial costs are 20% lower, but maintenance costs are 3 times higher over 5 years. Initial costs are comparable, but maintenance costs decrease by 70% over 5 years. Initial costs are 10% higher, but maintenance costs decrease by 80% over 5 years. Initial costs are 15% higher, but maintenance costs decrease by 85% over 5 years.

[0085] As shown in the table above, Examples 1 to 3, through bio-enhancement technology (three-dimensional network of fungal mycelium), multifunctional integrated design (UV resistance / water retention / root promotion / antibacterial), and precise degradation control, are significantly superior to the physical weaving + chemical fiber reinforcement scheme of the control example. Specifically:

[0086] Improved windbreak and sand fixation efficiency: The synergistic effect of the mycelium reinforcement layer and the nano-coating increases the reduction rate of wind speed and the reduction rate of sand transport behind the barrier by 20%-25% and 25%-29% respectively compared with the control.

[0087] Breakthrough in durability and ecological safety: Bio-based fibers replace chemical fibers, avoiding microplastic pollution. At the same time, the cross-sectional bonding strength of mycelium is increased by 5 times compared with the control example of physical weaving, and the grid integrity rate is increased from 40% to over 90%.

[0088] Enhanced vegetation synergy: The root-promoting additives and water-retention function increased the survival rate of sand willow seedlings from 60% to 93%-97%, and the root growth increased by 30%-50%, forming a "biological-mechanical" composite sand fixation system.

[0089] Controllable degradation cycle: By adjusting the substrate pretreatment process (such as steam explosion intensity) and coating formulation, the degradation cycle can be precisely matched with the vegetation restoration rhythm (6-36 months), while the control case requires manual recycling due to chemical residues, which is costly and pollutes the environment;

[0090] Functional scalability: Examples 2 / 3 introduce additional functions such as antibacterial and intelligent humidity response to adapt to the needs of different desert environments, while the control example has only one function and cannot cope with complex ecological challenges.

[0091] In summary, through material innovation and structural optimization, the embodiments of the present invention comprehensively surpass existing technologies in terms of performance, environmental protection, and economy, providing an efficient and sustainable solution for desertification control.

[0092] Application examples

[0093] Application example: Control of mobile sand dunes

[0094] On shifting sand dunes (slope 20°) in the Tengger Desert, sand barriers prepared in Example 2 were laid in a 2m × 2m grid pattern, with a density of 400 grids per hectare. After laying, sand willow seedlings were planted within the grids, spaced 1.5m apart, and supplemented with water using a micro-irrigation system (drip tape spacing 1m). After one year of observation:

[0095] Windproof effect: The wind speed at a height of 0-20cm behind the sand barrier is reduced by 55%, and the sand transport rate is reduced by 95%;

[0096] Vegetation restoration: The survival rate of sand willow was 93%, the average plant height increased by 1.2m, the root system and mycelium network formed a 15cm thick composite sand-fixing layer, and the soil organic matter content increased by 0.5%;

[0097] Degradation performance: The surface of the sand barrier began to degrade in 20 months and completely degraded in 26 months, during which no secondary pollution occurred.

[0098] The sand barrier of this invention achieves a balance of high strength, long degradation cycle and ecological compatibility through synergistic innovation of materials, processes and functions, providing a new technical solution for desertification control.

[0099] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fungal mycelium-reinforced biodegradable sand barrier based on Salix psammophila, characterized in that, Made from the following raw materials in percentage by weight: Substrate: 60%-75% of sand willow fiber particles (particle size 0.3-2.5mm), pretreated with steam explosion (pressure 1.5-2.5MPa, time 5-15 minutes) to destroy the lignin structure and improve the surface roughness; Biological binder: Fungal mycelial network (5%-18% dry weight), obtained through solid-state fermentation culture, in which the mycelium penetrates deep into the fiber to form a three-dimensional interwoven structure; Reinforcing fiber: It is made of polylactic acid (PLA) fiber (3-10mm in length) and bamboo fiber (5-15mm in length) mixed in a mass ratio of 2:1, with an addition amount of 8%-15%; Functional additives include nano silica (particle size 20-50nm, addition amount 0.5%-2%, used for UV protection), humic acid (addition amount 1%-5%, used for water retention and root promotion) and chitosan (addition amount 0.1%-1%, used to induce mycelium to secrete extracellular polymers).

2. The fungal mycelium-reinforced degradable sand barrier based on Salix psammophila according to claim 1, characterized in that, The fungal mycelium is Trichoderma, and its solid-state fermentation conditions are as follows: Matrix: Sand willow fiber granules and wheat bran are mixed at a mass ratio of 4:1; Environment: Temperature 25-32℃, humidity 65%-85%, incubation time 7-21 days; Inducer: Add chitosan or sodium lignin sulfonate at 0.1%-0.5% of the total matrix mass to promote the secretion of extracellular polymeric substances (EPS) by mycelium and enhance the interfacial bonding strength with fibers.

3. The method for preparing a fungal mycelium-reinforced degradable sand barrier based on *Salix psammophila* according to claim 1, characterized in that, Includes the following steps: Step 1: Substrate pretreatment: After crushing the sand willow branches, screen out the fiber particles with a particle size of 0.3-2.5mm, treat them with steam explosion (pressure 1.5-2.5MPa, time 5-15 minutes), soak them in 5% NaOH solution for 2 hours, wash them with water until neutral and dry them. Step 2, Mycelial Culture: The pretreated fibers are mixed with a fungal spore suspension (concentration 1×10⁻⁶). 6 -1×10 8 Mix (CFU / mL) at a mass ratio of 100:0.5-100:2, pack into an air-permeable mold, and culture under the conditions described in claim 2 until the mycelium covers more than 90% of the substrate surface; Step 3, Composite Molding: The reinforcing fibers, functional additives and mycelium-sand willow composite substrate are mixed and molded into sand barrier boards with a thickness of 1-5cm and a porosity of 25%-60% under a pressure of 10-30MPa and a temperature of 40-70℃. Step 4, Post-processing: Cut the sand barrier into 1m×1m or 2m×2m sizes, and spray the surface with a biodegradable coating containing humic acid and nano titanium dioxide (particle size <100nm), with a coating thickness of 0.1-0.5mm.

4. The method for preparing a fungal mycelium-reinforced degradable sand barrier based on *Salix psammophila* according to claim 3, characterized in that, During the molding process, biodegradable fiber ropes (made of polylactic acid fiber and flax fiber blend, with a diameter of 1-3mm) are pre-embedded in the mold to enhance the tear resistance of the sand barrier. The fiber rope spacing is 10-30cm.

5. The fungal mycelium-reinforced degradable sand barrier based on Salix psammophila according to claim 1, characterized in that, The degradation cycle of the sand barrier is achieved by adjusting the mycelium content and the proportion of functional additives: Short-term degradation type (6-12 months): mycelium content 5%-8%, nano silica addition 0.5%-1%, humic acid addition 1%-2%; Long-term degradable type (18-36 months): mycelium content 12%-18%, nano silica addition 1%-2%, humic acid addition 3%-5%.

6. The fungal mycelium-reinforced degradable sand barrier based on Salix psammophila according to claim 1, characterized in that, The surface of the sand barrier is provided with a diamond-shaped or wavy textured structure with a groove depth of 0.5-2cm, which is used to intercept fine particulate matter (particle size <0.05mm) in the wind and sand flow.

7. The fungal mycelium-reinforced degradable sand barrier based on Salix psammophila according to claim 1, characterized in that, The method of sand fixation through the synergistic action of sand barriers and plant roots is as follows: after the sand barriers are laid, at least one of sand willow, caragana, or tamarisk is planted within the grid. The water retention capacity of the sand barriers (water holding rate ≥200%) and the root-promoting effect of humic acid (root growth increases by 30%-50%) are utilized to form a composite sand fixation system with the plant roots and mycelial network.

8. The application of the fungal mycelium-enhanced degradable sand barrier based on Salix psammophila according to claim 1 in desertification control, characterized in that, It is suitable for the treatment of mobile dunes, semi-fixed dunes or wind erosion pits. The laying methods include square, strip or fish scale, with a laying density of 150-600 grids per hectare, and it is used in conjunction with micro-irrigation systems.

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