A method for sand-fixing by biological engineering of cluster sand barriers

Abstract

The application discloses a cluster-shaped sand barrier bioengineering sand-fixing method and belongs to the technical field of ecological protection and desert control, and is used for solving the problems of large labor quantity, large construction difficulty, high cost, disconnection between engineering sand-fixing and biological sand-fixing, low plant survival rate and poor sand-fixing effect in traditional sand control technology. The five-step implementation of the method is as follows: pelletization or functional carrier preparation is carried out on the seeds of sand-growing native shrubs and grasses, plant straws are classified and pretreated into unprocessed cluster-shaped straws or processed straw curtain / straw rope straws with preset seeds, cluster-shaped sand barriers are processed according to the set specifications, seed direct seeding or preset seed methods are adopted to complete shrub and grass seeding or cluster-shaped planting according to different sand barrier types, and sand-enclosing and grass-planting and grazing-prohibiting management is implemented for 3 years. The method realizes the cooperative operation of engineering sand-fixing and biological sand-fixing, realizes physical wind prevention of the sand barrier, realizes fertilizer supply by straw degradation, realizes long-acting sand-fixing of shrubs and grasses in stages, greatly improves the plant survival rate and sand-fixing efficiency, reduces the material and labor costs, and is suitable for desertification control of mobile sand land, sand dunes, deserts, seriously degraded grasslands and abandoned wasteland.

Description

Technical Field

[0001] This invention relates to the fields of ecological protection and desertification control, specifically to a bioengineering method for sand fixation using clustered sand barriers. Background Technology

[0002] As a highly mobile and unique natural disaster, sandstorms destroy large amounts of farmland, villages, roads, and trees every year, causing numerous inconveniences to production, daily life, and travel. It is a primary technical issue in the battle against sandstorms along the Yellow River, the Three-North Shelterbelt Project, and the construction of a beautiful new Ningxia.

[0003] Practice has proven that laying straw checkerboard mats is the most effective means of engineering-based desertification control. It can significantly reduce wind speed, and the cyclical laying of decomposed straw can form a sand crust to stabilize shifting sand. The mechanical insertion of straw checkerboard mats improves efficiency and reduces costs. Mechanized desertification control is not only effective and efficient but also scientifically sound, accelerating desertification control and having significant implications for ecological construction. It represents the future direction for desertification control.

[0004] Current mainstream sand fixation methods have many significant drawbacks. Traditional straw checkerboard methods rely on manual laying, which is difficult, inefficient, and labor-intensive due to the harsh desert environment. The large amount of labor and materials required, coupled with the time lag compared to biological sand control processes, further increases the cost and difficulty of sand control. At the same time, the proportion of straw buried in the soil is high, while the exposed portion is relatively low, resulting in poor control effect. Since the exposed portion is scattered, it is easily eroded by wind, which is not conducive to long-distance transportation and mechanized operations. In addition, straw checkerboards made of wheat straw, sand willow, etc. are easily weathered and have a short lifespan.

[0005] While afforestation offers long-term benefits, deserts struggle to retain moisture, seedlings easily wither, and it takes over a decade to form a protective forest. During this time, seedlings may be blown down and buried by shifting sands, resulting in a low survival rate. Although various mechanical sand-fixing vehicles use straw checkerboard grids, which are of higher quality and can reduce wind and trap rainwater, they are expensive and not widely adopted. Furthermore, they are only suitable for large, open, flat areas and cannot address the challenges of desert hilly terrain.

[0006] In addition, watering is required after sowing seeds or planting seedlings, which increases labor costs and wastes water resources. Separating the construction of plant-based sand control and straw checkerboard sand fixation also increases labor costs.

[0007] Therefore, the urgent need for sand prevention and control at present is to improve the level of mechanization in sand fixation and afforestation, and to develop equipment, treatment technologies and supporting procedures that are suitable for different terrains and have appropriate costs. Summary of the Invention

[0008] To overcome the aforementioned difficulties and break through the limitation of not being able to combine straw sand control and biological sand fixation, this invention proposes a cluster-shaped sand barrier bioengineering sand fixation method to shorten the effective time of plant sand fixation, improve plant survival rate and sand fixation effect. This method employs cluster-shaped engineering sand barriers, biological methods, or a combination of engineering and biological methods. Before construction, straw and other materials are bundled into clusters. One end of each cluster can be pre-placed with seed packets, seed ropes, water-retaining agents, or biological agents. Plant seeds are sown in the gaps of the physical sand-fixing structure rather than on the sand surface using a mixed sowing method of shrubs and straw. The sand surface crust prevents sand from shifting, effectively improving the sand fixation effect, ensuring plant survival rate, reducing material and labor costs, and allowing the plants to complement each other in stages to achieve sand fixation and ultimately form a stable habitat.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A bioengineering method for sand fixation using clustered sand barriers, including Step 1, Seed Pretreatment Select shrub and herb seeds of native psammophytic plants. When the seed size difference is too large, first pellet the small-sized seeds, heteromorphic seeds or awned seeds so that the treated seeds have the same or similar diameter as the large-sized seeds. Seeds are prepared as naked seeds, or in seed packets, seed ropes, seed pellets, or seed cups containing water-retaining agents, biological agents, and humic acids; the seed packets, seed ropes, seed pellets, or seed cups are made of degradable materials so that they can be directly buried in the soil to degrade and release nutrients. Step 2, Sand Barrier Pretreatment When using unwoven plant straw as sand barriers, the loose plant straw is fixed at the top and bottom with weather-resistant hard materials and bundled into a cluster of straw for later use; When using woven plant straw as a sand barrier, loose plant straw is woven into straw curtain or straw rope shape. During the weaving process, pre-treated seeds are embedded into the straw to form a straw curtain / straw rope shape with a pre-placed seed bag, seed rope, seed ball or seed cup at one end, for later use. Step 3: Constructing Clustered Engineering Sand Barriers The pre-treated straw sand barriers are then tied together: When using unwoven clumps of straw: tie them directly to the sand surface to form clumps of sand barriers; When using woven straw mats / straw ropes: tie them together in a cluster on the sand surface to form a clustered sand barrier. During the tying process, make the end with the pre-set seed pack, seed rope, seed pellet or seed cup face the direction of the shifting sand, and the direction of the seed rope is parallel to the direction of the sand barrier on the ground. The parameters for the constructed clustered sand barriers are: height 20-50cm, width 10-15cm, and burial depth 10-20cm. The spacing between clusters of sand barriers is 0.5 to 1 meter, with a spacing of 0.5 meters on the windward and leeward slopes and 0.5 to 1 meter on flat sandy areas. The laying patterns of clustered sand barriers include dotted clusters, square grids, triangular patterns, linear patterns, strip patterns, ring patterns, or irregular patterns; Step 4, mixed sowing of shrubs and grasses When the clump-shaped sand barrier is an unwoven clump of straw, pretreated shrub and herb seeds are sown in the projection range and gaps of the clump-shaped sand barrier according to the set ratio and sowing amount. The sowing rate for mixed shrubs and grasses is 1.0~1.5 kg / mu; Sowing time can be before the rainy season, during the rainy season, or in winter, with the rainy season being the preferred time. Step 5, Post-Management The sand-sealing and grass-cultivation method will be adopted, and grazing will be prohibited for 3 years to avoid disturbing the sand surface.

[0011] The beneficial effects of this invention are as follows: The sand-fixing method of this invention involves pre-treating seeds and sand barriers before construction, which greatly reduces the labor involved in seed treatment and straw barrier construction. At the same time, the clustered structure reduces the amount of straw used per unit area and the ineffective losses after construction, increases the height of the straw barriers, improves the windproof effect, and extends the service life of the straw barriers. Because the windward and leeward slopes of the sand dunes are densely covered with barriers, the construction is more site-specific and based on the specific hazards, which enhances the overall stability of the sand surface in the treated area and reduces the occurrence of sand damage.

[0012] In the early stages of sand barrier construction, this invention utilizes mechanical binding, manual weaving, mechanical pressing, and mechanical packaging to limit approximately 80-90% of the work to factories or farmers' homes, facilitating factory-style construction. For field construction, the finished product is simply installed onto the sand surface according to the engineering implementation plan, achieving one-time construction and one-time shaping. During wind erosion, occasional wind-induced damage can cause the fallen clustered structures to be reshaped, forming a complete barrier interface without the need for specific manual maintenance later.

[0013] This invention, during sand barrier construction, incorporates granulated seed packets, seed ropes, seed pellets or cups, and functional planting bags. The seed packets and seed ropes are made from recycled and biodegradable materials, achieving waste resource utilization, reducing seedling costs, and avoiding the "transplant shock" problem during seedling transplantation. By organically combining grass barrier engineering with biological sand control, it enables dry sowing and wet emergence or sowing during periods of soil moisture, allowing for year-round construction and significantly extending the construction period. No fertilization or watering is required throughout the process, conserving water resources and seed consumption in desert areas and solving the problem of seed survival difficulties due to lack of water and fertilizer. Construction can combine mechanization and manual labor, greatly reducing labor costs and the input of human and material resources.

[0014] The clump-shaped sand barriers formed by grass have a certain height, which can play a preliminary role in sand fixation as a physical sand-fixing structure, causing wind and sand to flow around and reducing wind speed. At the same time, plants growing in the gaps of the grass barrier can effectively reduce the damage to plants from shifting sand and strong winds with the help of the barrier formed by the straw. It also has a root-fixing and protective effect on the roots of early-growing seeds or seedlings, which is conducive to plant growth and improves the survival rate. Since plant straw, such as wheat straw, is organic matter and has a certain water retention capacity, the grass barrier can provide the organic nutrients needed for plant growth after 2-3 years of decomposition and degradation, and has a certain water storage effect during the rainy season. The grass barrier reduces water loss, while keeping it warm, breathable, and water-retaining, and can protect plant roots, thus improving the survival rate of crops.

[0015] The grass barrier solidifies the sand surface into a biological crust, which helps to conserve soil, stabilize sand, and prevent excessive evaporation of groundwater. Since plant seeds are planted in the gaps of the grass barrier, rather than on the traditional grid-like sand surface, the sand surface becomes adhered after the crust forms, which essentially eliminates the presence of quicksand. This prevents plants from being buried or covered by quicksand in the early stages of germination, providing favorable conditions for their growth. The sheet-like sand surface after the biological crust also has a rain-collecting effect, which can collect rainwater in the gaps of the grass barrier during the rainy season.

[0016] This invention employs a mixed sowing method of shrubs and grasses, where plant seeds are sown within the projection area of ​​the grass barrier. The plant seeds germinate and grow through the gaps in the straw, no longer adversely affected by the fixed sand surface, and are protected by the straw, significantly improving the survival rate of the plants and thus playing a phased role in sand fixation. The mixed sowing method of shrubs and grasses can increase the species richness and diversity in the area. The combination can be at least one type of shrub and at least one type of herbaceous plant. Since herbaceous plants germinate and grow quickly, they can play a sand-fixing role in a short time and maintain it for about one year, while providing favorable conditions for the growth of shrubs. As the shrub seedlings grow, the herbaceous plants gradually withdraw, and the shrubs begin to play a sand-fixing role, fully forming a biological sand barrier in about 2 to 3 years, and playing a long-term sand-fixing role.

[0017] At the same time, clustered biological sand barriers can be constructed by using suitable trees, shrubs, herbs, or mixed combinations of trees, shrubs, and herbs based on planting methods such as sowing, seedling planting, and cutting propagation. By combining clustered engineering sand barriers with clustered biological sand barriers, composite sand barriers that combine engineering and biology can be constructed.

[0018] This invention makes full use of the growth characteristics of different plants and increases their mutual benefit, so that they complement and benefit each other during the growing season, forming a new low-density, near-natural afforestation and management method. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic diagram of the clustered sand barrier structure of the present invention; Figure 2 , Figure 3 , Figure 4 This is a schematic diagram of several optional clustered sand barrier spatial layouts for the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention relates to a bioengineering method for sand fixation using clustered sand barriers, comprising the following steps: Step 1, Seed Pretreatment Select shrub and herb seeds of native psammophytic plants. When the seed size difference is too large, first pellet the small-sized seeds, heteromorphic seeds or awned seeds so that the treated seeds have the same or similar diameter as the large-sized seeds. Seeds are prepared as naked seeds, or in seed bags, seed ropes, seed pellets, or seed cups containing water-retaining agents, biological agents, and humic acids; the seed bags, seed ropes, seed pellets, or seed cups are made of recycled and degradable materials, which are then buried in the soil to degrade and release nutrients.

[0023] The seeds used in this embodiment are mainly native psammophytic plants, especially pioneer plant seeds suitable for shifting sand control. These seeds can be shrub or herbaceous plant seeds, sand-dry shrubs or grasses, or seedlings. Optionally, the shrub seeds include at least one of *Populus tomentosa*, *Caragana korshinskii*, *Artemisia scoparia*, and *Caragana sinica*; the herbaceous seeds include at least one of *Amaranthus praecox*, *Osmanthus fragrans*, and *Astragalus membranaceus*.

[0024] The aforementioned biological agents are generally formulated from one, two, or more functional bacterial strains, and can be formulated from at least one functional strain selected from arbuscular mycorrhizal fungi, Bacillus subtilis, Bacillus megaterium, and actinomycetes. Common combinations include arbuscular mycorrhizal fungi + Bacillus subtilis, and Bacillus megaterium + actinomycetes. These combinations can synergistically exert effects such as "root expansion and water absorption + nutrient activation + physiological regulation," making them suitable for forest cultivation under different site conditions. However, care should be taken to avoid simultaneous application with high-concentration fungicides and fertilizers to prevent inhibition of the survival of beneficial microorganisms.

[0025] Step 2, Sand Barrier Pretreatment The sand barrier described in this embodiment is made from loose wheat straw or other plant stalks. When using unwoven plant straw as sand barriers, the loose plant straw is fixed at the top and bottom with 2-3 layers of weather-resistant hard material and bundled into a bunch of straw. The height of the whole bunch of straw is 30-60cm, and it is ready for use. When using woven plant straw as sand barriers, the loose plant straw is woven into straw curtains or straw ropes. During the weaving process, pre-treated seeds are embedded into the straw, forming straw curtains / straw ropes with pre-placed seed packets, seed ropes, seed pellets, or seed cups at one end, which are then ready for use. This step, by weaving seeds into the sand barrier, forms an integrated process of "water conservation-seedling cultivation-sand fixation," which can achieve the goals of saving labor, water, and seeds, significantly reducing water and seed consumption in desert areas, and solving the problem of seed survival caused by lack of water and fertilizer.

[0026] Optionally, when weaving straw mats / straw ropes with pre-placed seed ropes, one or more seed ropes are woven. When multiple ropes are woven simultaneously, the various seed ropes are woven at different positions on the straw mats / straw ropes. When the sand barrier is constructed, the depth is adjusted to bury different seeds at appropriate depths, so as to achieve the purpose of different sowing depths in the application of sand barrier desertification control, and to ensure that most desert plants can germinate normally.

[0027] Step 3: Constructing Clustered Engineering Sand Barriers Reference Figure 1 The pretreated straw sand barriers are then tied together. When using unwoven clumps of straw: tie them directly to the sand surface to form clumps of sand barriers; When using woven straw mats / straw ropes: tie them together in a cluster on the sand surface to form a clustered sand barrier. During the tying process, make the end with the pre-set seed pack, seed rope, seed pellet or seed cup face the direction of the shifting sand; and the direction of the seed rope is parallel to the direction of the sand barrier laying on the ground. Use an adjustable laying machine to bury the seeds at a suitable depth. The parameters for the constructed clustered sand barriers are: height 20-40cm, width 10-15cm, and burial depth 10-20cm. The spacing between clusters of sand barriers is 0.5 to 1 meter, with a spacing of 0.5 meters on the windward and leeward slopes and 0.5 to 1 meter on flat sandy areas.

[0028] The sand barriers are laid out in a scattered cluster pattern.

[0029] Reference Figures 2 to 4In other embodiments, the clodded sand barriers can be laid in any of the following forms for sand control: grid-like, triangular, linear, strip-like, ring-like, or irregular. The sand barriers formed by the clodded sand barriers have a certain height, playing a preliminary role in sand fixation. Plants growing in the gaps of the straw barriers, with the help of the barrier formed by the straw, can effectively reduce the damage to plants from shifting sand and strong winds. It also provides root support and protection for early-germinating seeds or saplings, which is beneficial to plant growth and significantly improves the survival rate.

[0030] Step 4, mixed sowing of shrubs and grasses When the clump-shaped sand barrier is made of unwoven clump-shaped straw, pretreated shrub and herb seeds are sown in the orthographic projection range and gaps of the clump-shaped sand barrier according to a set ratio and sowing amount. For example, the plant seeds for shrub-grass mixed sowing include, but are not limited to, *Populus tomentosa*, *Caragana korshinskii*, *Artemisia scoparia*, *Caragana sinica*, *Amaranthus praecox*, *Osmanthus fragrans*, and *Astragalus membranaceus*. Alternatively, the combination of plant seeds for shrub-grass mixed sowing includes at least one shrub and at least one herb, especially seeds of perennial herbs and shrubs, or shrubs and shrubs mixed together. For example, the combination of plant seeds for shrub-grass mixed sowing can be three shrubs and one herb: the shrubs can be *Populus tomentosa*, *Caragana korshinskii*, and *Artemisia scoparia*, and the herb can be *Amaranthus praecox* or *Osmanthus fragrans*.

[0031] This embodiment adopts a mixed sowing method of shrubs and grasses, sowing plant seeds within the projection range of the sand barrier, which can significantly improve the survival rate of plants and allow shrubs and grasses to play a role in sand fixation in stages and periods: because herbaceous plants germinate and grow quickly, they can play a role in sand fixation in a short time. For example, sweet clover can grow to 10-20cm within 2 months of the rainy season and maintain this growth for 1-3 years, providing favorable conditions for the growth of emerging shrubs; as the shrub seedlings grow, the herbaceous plants gradually withdraw after about 1-2 years, at which time shrubs, such as Artemisia annua, begin to play a role and completely form a biological sand barrier in about 2-3 years.

[0032] The mixed sowing of shrubs and grasses can increase the richness and diversity of species in the region, make full use of the growth characteristics of different plants, and make them complementary and mutually beneficial during the growing season.

[0033] Preferably, the sowing rate for mixed shrubs and grasses is 1.0~1.5 kg / mu.

[0034] Sowing time can be before the rainy season, during the rainy season, or in winter. To further improve the germination and emergence rate of seeds, the rainy season is preferred.

[0035] Step 5, Post-Management The sand-sealing and grass-cultivation method will be adopted, and grazing will be prohibited for 3 years to avoid disturbing the sand surface.

[0036] The crusted sand surface adheres to the ground, effectively eliminating the presence of shifting sand. This prevents early germination of plants from being buried or covered by shifting sand, providing favorable conditions for their growth. The crusted sand surface also has a rain-collecting effect, gathering rainwater into the gaps in the straw barrier during the rainy season. Since wheat straw itself is organic matter, it has a certain water storage capacity, providing the organic nutrients and water needed for plant growth.

[0037] After 2 to 3 years, the grass barrier gradually decomposes and degrades, and its organic matter can provide valuable nutrients for desert plants. At this time, the shrubs have grown vigorously. As time goes by, after 3 to 5 years, the sheet-like sand surface that has formed a crust will gradually begin to collapse and disintegrate. However, at this time, the biological sand barrier has basically been formed and will play a stable role in sand fixation for a long time.

[0038] The sand-fixing method in this embodiment is a novel low-density, near-natural afforestation method. Due to its high plant survival rate, the planting density does not need to be too high, allowing for "quantity over quality," thus saving plant seeds. In specific construction, mechanical and manual methods can be combined, which will significantly reduce labor costs and manpower and material resources.

[0039] More preferably, in step two, the sand barrier pretreatment also includes functional vegetation bag pretreatment: Prepare functional planting bags containing 10-20 viable seeds. In step three, when the unwoven clumps of straw are tied into clumps to form sand barriers, wrap the planting bag around one end of the sand barrier root and bury it in the sand simultaneously. This can replace step four, organically combining grass barrier engineering for sand control with biological sand control, and carrying out construction simultaneously.

[0040] More preferably, in step three, while constructing the clustered engineering sand barriers, suitable trees, shrubs, and grasses are simultaneously planted in clusters to create living sand barriers: Drawing on engineering desertification control technology theory, this paper applies biological active sand barrier sand fixation technology. It adopts seedlings, cuttings or seeds of sandy land-suitable trees, shrubs or grasses such as Salix matsudana, Pinus sylvestris, Salix psammophila, Salix babylonica, Caragana korshinskii, Caragana sinica, Populus tomentosa or Salix matsudana, Osmanthus fragrans, and Astragalus membranaceus. Combined with supporting technical measures such as soil preparation, water injection afforestation, drought-resistant covering, replanting and reseeding, one, two or more of the above-mentioned trees, shrubs or grasses are planted in clusters to create biological sand-fixing barriers with clusters of trees, shrubs, herbs or a combination of trees, shrubs, grasses or trees, shrubs and grasses. This achieves biological active sand barrier sand fixation technology based on the cluster sand control theory.

[0041] In this embodiment, the main parameters of the clump-shaped biological sand barrier after afforestation are: height 20~250cm, width of each clump 10~300cm; herbaceous plants can be broadcast or mechanically sown, with a mechanical sowing depth of 10~15cm; seedling planting depth: shrubs 15~30cm, trees 30~50cm; the clump spacing of the clump-shaped sand barrier is determined according to the appropriate planting density of trees, shrubs and grasses.

[0042] Optionally, the paving patterns of clustered sand barriers include square, triangular, linear, strip, ring, or irregular shapes.

[0043] This embodiment can fully utilize engineering sand control technology and biological active sand barrier sand fixation technology to build a cluster-shaped sand control technology network based on the combination of engineering sand control and tree, shrub and grass biological sand barriers, so as to achieve a cluster-shaped sand fixation system that is effective in one treatment, long-term results and system stability.

[0044] The following detailed description of the sand fixation method of the present invention, in conjunction with specific embodiments, will fully illustrate its technical content.

[0045] Example 1: Flat sandy land, without loose straw sand barriers + direct seeding for sand fixation.

[0046] This embodiment addresses desertification control in flat sandy areas by using sand barriers constructed from loose, unwoven plant straw, combined with direct seeding of bare plants. Specific steps include: Step 1, Seed Pretreatment Seeds of native desert plants were selected, including shrub seeds of *Populus edulis* and *Artemisia argyi*, and herbaceous seeds of *Alternanthera philoxeroides*. Because the seed size of *Alternanthera philoxeroides* differs significantly from that of shrub seeds, the seeds were first pelleted to make their diameter similar to that of *Populus edulis* and *Artemisia argyi*. The pelleted seeds were then mixed with the shrub seeds to prepare naked seeds coated with a water-retaining agent for later use.

[0047] Step 2, Sand Barrier Pretreatment Loose wheat straw was selected as the raw material for sand barriers, and galvanized iron wire was used as the weather-resistant hard material. Two knots were tied at the top and bottom of the loose wheat straw for fixation. The straw was then bundled into a cluster of straw with a height of 40-60cm and neatly arranged for use.

[0048] Step 3: Constructing the clustered sand barriers The pre-treated clumps of straw were directly tied together on the flat sandy surface to form a grid-like sand barrier. After the barrier was completed, the parameters were controlled as follows: height 50cm, width 12cm, and burial depth 15cm; the clump spacing was set to 0.8m according to the standard for flat sandy ground to ensure that the sand barrier was evenly and stably arranged.

[0049] Step 4, mixed sowing of shrubs and grasses Within the orthographic projection range of the clustered sand barriers and its internal gaps, pre-treated mixed seeds were sown using a tractor-driven mechanical broadcasting method according to a preset ratio; the sowing rate of the mixed shrub and grass was controlled at 1.2 kg / mu, and the sowing time was selected during the rainy season in sandy areas to ensure the seed germination rate.

[0050] Step 5, Post-Management The management method of sealing sand and cultivating grass is adopted. For three years after the completion of construction, grazing of livestock is strictly prohibited to prevent livestock from trampling, grazing and disturbing the sand surface and sand barriers, so as to ensure the stability of the sand barrier structure and the germination of seeds and the growth of seedlings.

[0051] Example 2: Weaving straw rope-like sand barriers on the windward slope of sand dunes and pre-planting seeds for sand fixation.

[0052] This embodiment addresses the control of shifting sand on the windward slope of sand dunes by using straw ropes to construct sand barriers. Seed ropes are pre-embedded during the straw weaving process, eliminating the need for additional direct seeding. Specific steps include: Step 1, Seed Pretreatment Seeds of native desert plants were selected, with shrub seeds from *Caragana korshinskii* and *Caragana chinensis*, and herbaceous seeds from *Osmanthus fragrans*. The mixed seeds were prepared into seed ropes carrying arbuscular mycorrhizal fungi bio-inoculant. The seed ropes were made of biodegradable materials and could naturally degrade and release nutrients after being buried in the soil.

[0053] Step 2, Sand Barrier Pretreatment Loose wheat straw is selected as raw material and woven into straw ropes. During the weaving process, a pre-treated seed rope is embedded inside the straw rope, so that the straw rope has a structure with a pre-placed seed rope at one end. After weaving, it is ready for use.

[0054] Step 3: Constructing Clustered Engineering Sand Barriers On the windward slope of the sand dunes, pre-treated straw ropes are bundled into triangular clusters to form sand barriers. During the bundling process, the end of the straw rope with the pre-placed seed rope is oriented towards the direction of the shifting sand, while ensuring that the direction of the seed rope is parallel to the direction of the sand barrier laying on the ground. After the sand barriers are completed, the parameters are controlled as follows: height 30cm, width 10cm, and burial depth 10cm. The cluster spacing on the windward slope is set to 0.5m to improve the stability of sand fixation on the windward slope.

[0055] Simultaneously, suitable trees, shrubs, and grasses are planted in clusters to create a living sand barrier: Using seedlings of sandy land-suitable trees, shrubs, and grasses such as Salix matsudana, Salix psammophila, Caragana korshinskii, Populus tomentosa, Osmanthus fragrans, and Astragalus membranaceus, combined with supporting technical measures such as soil preparation during moisture retention, water injection for afforestation, drought-resistant mulching, and replanting and reseeding, the above-mentioned seedlings of trees, shrubs, and grasses are planted in clusters at the center of the triangular-shaped sand barrier to create a biological sand-fixing barrier that combines clustered trees, shrubs, and herbs, thus realizing the biological living sand barrier sand fixation technology based on the clustered sand control theory.

[0056] The main parameters of the clump-shaped biological sand barrier after afforestation are: height 20~250cm, width of each clump 10~300cm; herbaceous plants can be broadcast or mechanically sown, with a mechanical sowing depth of 10~15cm; seedling planting depth: shrubs 15~30cm, trees 30~50cm.

[0057] Step 4, mixed sowing of shrubs and grasses Since the seeds are pre-set during the weaving of the straw ropes, no additional straw mixing and sowing is required in this step.

[0058] Step 5, Post-Management The management method of sealing sand and cultivating grass is adopted. Grazing is prohibited for 3 years from the completion of construction. The stability of the sand barriers is inspected regularly, and the sand barriers that are washed away or damaged by shifting sand are repaired in a timely manner to provide a stable environment for plant growth.

[0059] Example 3: Severely degraded grassland without straw sand barriers + functional vegetation bags for sand fixation.

[0060] This embodiment targets the ecological restoration of severely degraded grasslands, employing a method of constructing sand barriers from unwoven loose straw, combined with pre-filled seeds in functional planting bags. Specific steps include: Step 1, Seed Pretreatment Seeds of native desert plants were selected, with shrub seeds from Caragana korshinskii and herbaceous seeds from Astragalus membranaceus. The two types of seeds were mixed and prepared into seed pellets containing humic acid and Bacillus subtilis for later use.

[0061] Step 2, Sand Barrier Pretreatment On the one hand, loose sand willow stalks were selected as the raw material for sand barriers. Three fixation ropes were used to tie the stalks at the top and bottom to form a bundle of stalks with a height of 50cm. On the other hand, functional planting bags were prepared, each containing 15 viable seeds, which were then pre-treated twice before use.

[0062] Step 3: Constructing the clustered sand barriers The pre-treated clumps of straw are tied into strips of clumps on the sandy surface of severely degraded grassland. During the tying process, functional planting bags are wrapped around one end of the root of the sand barrier and buried in the sand at the same time as the sand barrier. After the sand barrier is completed, the parameters are controlled as follows: height 20cm, width 15cm, burial depth 20cm; clump spacing is set to 1m to meet the needs of degraded grassland restoration.

[0063] Step 4, mixed sowing of shrubs and grasses Since the functional planting bags are pre-filled with seeds, this step does not require additional shrub and grass mixing.

[0064] Step 5, Post-Management The management method of sealing sand and cultivating grass is adopted. Grazing is prohibited for 3 years from the completion of construction to avoid human and livestock disturbance of the sand surface, protect the sand barrier and the germinating seedlings, and help the degraded grassland to quickly form a sand-fixing vegetation community.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for sand fixation through bioengineering using clustered sand barriers, characterized in that, include Step 1, Seed Pretreatment Select shrub and herb seeds of native psammophytic plants. When the seed size difference is too large, first pellet the small-sized seeds, heteromorphic seeds or awned seeds so that the treated seeds have the same or similar diameter as the large-sized seeds. Seeds are prepared as naked seeds, or in seed packets, seed ropes, seed pellets, or seed cups containing water-retaining agents, biological agents, and humic acids; the seed packets, seed ropes, seed pellets, or seed cups are made of degradable materials so that they can be directly buried in the soil to degrade and release nutrients. Step 2, Sand Barrier Pretreatment When using unwoven plant straw as sand barriers, the loose plant straw is fixed at the top and bottom with weather-resistant hard materials and bundled into a cluster of straw for later use; When using woven plant straw as a sand barrier, loose plant straw is woven into straw curtain or straw rope shape. During the weaving process, pre-treated seeds are embedded into the straw to form a straw curtain / straw rope shape with a pre-placed seed bag, seed rope, seed ball or seed cup at one end, for later use. Step 3: Constructing Clustered Engineering Sand Barriers The pre-treated straw sand barriers are then tied together: When using unwoven clumps of straw: tie them directly to the sand surface to form clumps of sand barriers; When using woven straw mats / straw ropes: tie them together in a cluster on the sand surface to form a clustered sand barrier. During the tying process, make the end with the pre-placed seed pack, seed rope, seed pellet or seed cup face the direction of the flowing sand. The parameters for the constructed clustered sand barriers are: height 20-50cm, width 10-15cm, and burial depth 10-20cm. The spacing between clusters of sand barriers is 0.5 to 1 meter, with a spacing of 0.5 meters on the windward and leeward slopes and 0.5 to 1 meter on flat sandy areas. The laying patterns of clustered sand barriers include dotted clusters, square grids, triangular patterns, linear patterns, strip patterns, ring patterns, or irregular patterns; Step 4, mixed sowing of shrubs and grasses When the clump-shaped sand barrier is an unwoven clump of straw, pretreated shrub and herb seeds are sown in the projection range and gaps of the clump-shaped sand barrier according to the set ratio and sowing amount. The sowing rate for mixed shrubs and grasses is 1.0~1.5 kg / mu; Sowing time is before the rainy season, during the rainy season, or in winter; Step 5, Post-Management The sand-sealing and grass-cultivation method will be adopted, and grazing will be prohibited for several years to avoid disturbing the sand surface.

2. The method for sand fixation using clustered sand barriers according to claim 1, characterized in that: In step one, the shrub seeds include at least one of *Populus tomentosa*, *Caragana korshinskii*, *Artemisia argyi*, and *Caragana korshinskii*; the herb seeds include at least one of *Amaranthus praecox*, *Osmanthus fragrans*, and *Astragalus membranaceus*.

3. The method for sand fixation using clustered sand barriers according to claim 1, characterized in that: In step one, the biological agent is a compound of at least one functional strain selected from arbuscular mycorrhizal fungi, Bacillus subtilis, Bacillus megaterium, and actinomycetes.

4. The method for bioengineering sand fixation using clustered sand barriers according to claim 1, characterized in that: In step two, when bundling unwoven loose plant stalks, use weather-resistant hard materials to secure them 2-3 times at the top and bottom, and the height of the whole bundle of stalks should be 30-60cm.

5. The method for sand fixation using clustered sand barriers according to claim 1, characterized in that: Step two, the sand barrier pretreatment also includes the pretreatment of functional vegetation bags: Prepare a functional planting bag containing 10-20 seeds. In step three, when the unwoven clumps of straw are tied into a clump-shaped sand barrier, wrap the planting bag around one end of the sand barrier's root and bury it in the sand simultaneously.

6. The method for bioengineering sand fixation using clustered sand barriers according to claim 1, characterized in that: In step two, when weaving the straw curtain / straw rope-like stalk with pre-placed seed ropes, one or more seed ropes are woven. When multiple ropes are woven at the same time, the various seed ropes are woven in different positions on the straw curtain / straw rope-like stalk.

7. The method for bioengineering sand fixation using clustered sand barriers according to claim 1, characterized in that: In step three, while constructing the clustered engineering sand barriers, suitable trees, shrubs, and grasses are planted in clusters to create living sand barriers: Plant one, two or more of the following seedlings, cuttings or seeds of suitable trees, shrubs or grasses in sandy areas: Salix matsudana, Pinus sylvestris, Salix psammophila, Salix psammophila, Caragana korshinskii, Caragana sinica, Caragana chinensis, Populus tomentosa or Salix matsudana, Osmanthus fragrans, Osmanthus fragrans var. chinensis, and Astragalus membranaceus; in clusters to create biological sand-fixing barriers of clustered trees, shrubs, herbs or a combination of trees, shrubs, grasses or trees, shrubs and grasses. The main parameters of the clump-shaped biological sand barrier after afforestation are: height 20~250cm, width of each clump 10~300cm; herbaceous plants can be broadcast or mechanically sown, with a mechanical sowing depth of 10~15cm; seedling planting depth: shrubs 15~30cm, trees 30~50cm. The laying patterns of clustered sand barriers include square, triangular, linear, strip, ring, or irregular shapes.

8. The method for bioengineering sand fixation using clustered sand barriers according to claim 1, characterized in that: The sand-fixing method described herein is applicable to shifting sand dunes, deserts, severely degraded grasslands, or abandoned wastelands.

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