A composite soil conditioner for flowing aeolian soil and a method of using the same

Abstract

This invention relates to the field of soil conditioning or soil stabilizing materials, and discloses a composite soil conditioner for mobile sandy soil and its application method. Biomass particles with a polymer gel film on their surface are rolled in mobile sandy soil to form spherical structures encased in sand. The weight of these spherical structures presses down the sand, reducing wind erosion and effectively fixing the mobile sandy soil without affecting subsequent vegetation growth. Microbial agents within the film grow on the sand shell and biomass particles, producing organic acids that enhance mineral weathering, and releasing soluble calcium salts to maintain the strength of the sand shell. Long-lasting organic matter is decomposed by fungal pioneers, and combined with nutrients released from minerals and nitrogen-fixing bacteria regulating the carbon-nitrogen ratio, the growth of biofilm-producing bacteria, phosphorus- and potassium-solubilizing bacteria, and other engineered bacteria is maintained, producing a biofilm to continue maintaining soil particle aggregation and releasing nutrients to maintain fertility. The combination of these factors achieves sand fixation and supports vegetation growth, maintaining an organic matter supply and cycle.

Description

Technical Field

[0001] This invention relates to the field of soil conditioning materials or soil stabilizing materials, and in particular to a composite soil conditioner for mobile sandy soil and its application method. Background Technology

[0002] Aeolian sandy soil is a typical primary soil. Primary soil refers to soil with a weak degree of development, indistinct soil profile stratification, significant parent material characteristics, and a relatively young soil stage, which is clearly different from some soil types of zonal soils.

[0003] Initially prepared soil is extremely detrimental to vegetation growth, with the main adverse effects including: 1. Extremely barren, with a severe lack of nutrient supply: The organic matter content is extremely low, typically less than 0.5%, and sometimes even below 0.1%. It lacks the basic organic nutrients necessary for plant growth and the cementing substances that form the soil structure. The content of mineral nutrients such as nitrogen, phosphorus, and potassium is extremely low, containing almost no nutrients that plants can absorb. Similarly, due to the simple mineral composition and lack of adsorption carriers, trace elements are also generally deficient. Furthermore, due to the lack of nutrients and water, and the harsh physical environment, the number and activity of microorganisms and animals (such as earthworms) in the soil are extremely low, which is detrimental to organic matter decomposition, nutrient cycling, and soil structure improvement.

[0004] 2. Extremely poor water and fertilizer retention capacity: It has many large pores, resulting in weak water retention and capillary action. After rainfall or irrigation, water quickly infiltrates and is lost, causing the soil surface to dry out rapidly. It also has weak adsorption capacity, lacking clay particles and organic colloids, making it poor at adsorbing applied fertilizers and the already scarce soluble nutrients in the soil, which are easily leached away with water.

[0005] 3. The physical structure is unstable and susceptible to wind and water erosion: The soil particles are loose and lack structure. There is a lack of cementing material between soil particles, and the soil structure is very loose. It has poor erosion resistance and is easily blown and transported by wind and water. This leads to the loss of topsoil (and the small amount of nutrients and seeds that may be present in it), forming erosion pits or burying sand.

[0006] 4. The plants are subjected to severe physical stress. Soil has a low specific heat capacity, causing its temperature to rise rapidly during the day after absorbing solar radiation, and it also dissipates heat quickly at night, resulting in a large diurnal temperature range and causing heat stress to plant roots and seedlings. Moving sand dunes or sandstorms can bury seedlings and vegetation. Sand particles in sandstorms can cause physical damage (abrasion, impact) to plant stems and leaves.

[0007] Primary soil can gradually improve its development through natural forces, but this process is extremely slow, often taking tens of thousands of years. Artificial intervention can significantly accelerate this process. In densely populated areas, primary soil typically undergoes hundreds or even thousands of years of continuous transformation to achieve a significant improvement in its development, transforming it into fertile land. A typical example is some red soils in South and Southwest my country. These red soils were initially poorly developed and infertile, unsuitable for crops or other vegetation; many were considered wasteland until the Ming Dynasty. With the construction of irrigation facilities, through repeated flooding and drainage, under cyclical wet-dry and redox conditions, these red soils quickly accumulated considerable organic matter. The soil's physical properties and profile characteristics changed accordingly, forming an infiltration layer with a core-mass structure, a crystalline membrane, and significant iron and manganese deposits. Although not yet fertile, it was already usable as arable land. After decades of cultivation and improvement, this land is now fertile paddy soil.

[0008] However, not all regions have the necessary irrigation conditions. In areas lacking these conditions, current technologies employ a combination of chemical amendments and vegetation restoration. By incorporating bentonite and carboxymethyl cellulose, which have adhesive properties, the soil can quickly acquire a certain water and fertilizer retention capacity, allowing some well-developed root-forming plants to grow. However, the fertility of this improved soil remains limited for a considerable period, requiring regular topdressing for vegetation restoration. Furthermore, this approach consumes relatively high-cost chemical substances. Note that polyacrylamide is also a commonly used soil amendment polymer, but it is not suitable for long-term sand fixation because it has some biological activity and can be metabolized and consumed by microorganisms. Therefore, long-lasting substances like bentonite are still needed to improve the soil's water and fertilizer retention capacity.

[0009] Some newly formed soils, such as mobile aeolian sands, suffer from inherent soil problems and severe physical transport, making them not even static. Most mobile aeolian sands are located in arid regions with very little rainfall, the so-called deserts. For sand fixation in desert areas, there are mature physical fixation methods such as straw checkerboards, which can be effective for a long time due to the low rainfall. However, some areas, despite higher rainfall, experience mobile aeolian sands due to various factors. For these areas, straw checkerboards and similar techniques cannot be used for sand fixation (as they degrade very quickly). Currently, there are no better solutions for this problem.

[0010] Taking the research project on the mechanism and prevention strategies of various types of soil erosion under complex mountainous conditions, as an example, this project requires the improvement of aeolian sandy soil in Pai Town, Milin County, Nyingchi City. The project area is located in the Yarlung Tsangpo Grand Canyon, with extremely inconvenient transportation, and the local area lacks the capacity to produce fertilizers and chemical substances for soil improvement. The local precipitation reaches 650 mm, but the seasonal distribution of precipitation is uneven, with relatively dry winters. From October to March of the following year, strong afternoon winds (especially after 3-4 pm) blow up exposed sand from the riverbed, forming sandstorms. These factors have resulted in a series of large and small mobile aeolian sand dunes, the largest of which is the Danniang Sand Dunes in nearby Danniang Township. Vegetation cannot grow normally on the surface of these mobile aeolian sand dunes, and the topsoil is rapidly eroded. Without human intervention, the ecological situation will further deteriorate. If conventional methods are used for restoration, the large amount of raw materials needed would have to cross the entire Qinghai-Tibet Plateau and the Grand Canyon, which is not feasible. Summary of the Invention

[0011] This invention provides a composite soil conditioner for mobile aeolian sandy soil and its application method.

[0012] The technical problem to be solved is that: for land parcels with high precipitation and mobile sandstorms, mature solutions such as straw checkerboard sand fixation are not suitable, while soil improvement methods that combine chemical modification with vegetation restoration are costly and not applicable to areas with poor transportation.

[0013] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a composite soil conditioner for mobile sandy soil, used to improve mobile sandy soil in areas with annual precipitation exceeding 400 mm. The mobile sandy soil is initially fixed by a high molecular polymer, and then the sandy soil is improved in stages by using a variety of microbial agents and agricultural and forestry solid waste. The soil conditioner comprises the following components: The biomass particles used as carriers and fermentation substrates are dried plant powder, organic fertilizer powder, and oxygen channel organic matter used to prevent oxygen deficiency inside the biomass particles, wherein the oxygen channel organic matter is rice husk and / or crushed peanut shells. The polymer gel film used to form a sandy coating on the surface of biomass particles is the part remaining on the surface of the biomass particles after the biomass particles are soaked in a polymer solution containing a microbial agent. Sandy soil coatings are used to suppress the flow of wind-blown sand and provide a basis for the growth of microorganisms. The sandy soil coatings are sandy soil layers in which a polymer gel rolls and adheres in the flowing wind-blown sand. The microbial agent contains the following microbial strains: Acid-producing bacteria that enhance the weathering of minerals in the soil; Biofilm-producing bacteria used to generate biofilms that aggregate soil particles; Phosphorus- and potassium-solubilizing bacteria used to release insoluble nutrients from minerals; Nitrogen-fixing bacteria used to regulate the carbon-to-nitrogen ratio.

[0014] Furthermore, the composite soil conditioner is mixed into the top 5-15 cm of soil, and the concentration of each bacterial species in the polymer gel, calculated in CFU, is not less than 2 × 10⁻⁶. 7 CFU / g, total viable bacteria concentration not less than 4×10 8 CFU / g.

[0015] Furthermore, the acid-producing bacteria include Trichoderma reesei and white-rot fungi used to decompose biomass particles to produce small molecule organic matter including monosaccharides, acetic acid bacteria used to produce acetic acid, and Aspergillus niger used to produce citric acid and gluconic acid to form chelate salts and release small molecule carbon sources that can be utilized by acetic acid bacteria. The nitrogen-fixing bacteria include Azotobacter chrysotrichum, which is used to regulate the carbon-nitrogen ratio before vegetation grows, and Rhizobium and Freundii, which are used to regulate the carbon-nitrogen ratio after vegetation grows. The film-forming bacteria is Bacillus subtilis, and the phosphorus-solubilizing and potassium-solubilizing bacteria is Bacillus mucilaginosus.

[0016] Furthermore, the dried plant powder includes starchy organic matter used to provide carbon source for Aspergillus niger and acetic acid bacteria in the early stage, and long-lasting organic matter to provide carbon source for a long time in the later stage; the starchy organic matter is waste grain powder including aged grain powder and dried distiller's grains powder, and the long-lasting organic matter is lignified plant stem powder and / or mature plant stem powder. The mass ratio of the waste grain powder, long-lasting organic matter, organic fertilizer powder, and oxygen channel organic matter is 5-10:15-20:80:5.

[0017] Furthermore, the proportion range of each bacterial species in the bacterial agent, calculated in CFU, is as follows: Acid-producing bacteria: 50-60% in total, of which: Trichoderma reesei: 15-21%; White rot fungi: 10-14%; Acetic acid bacteria: 5-10%; Aspergillus niger: 15-20%; Nitrogen-fixing bacteria: 25-30% in total, of which: Azotocinus chrysophytes: 15-20%; Rhizobium + Freundii: 5-10%; Film-forming bacteria: 5-10% in total, of which: Bacillus subtilis 5-10%; Phosphorus- and potassium-solubilizing bacteria: Total 5-10%, of which: 5-10% of Bacillus jellyii.

[0018] Furthermore, the polymer solution is a mixed solution of polyacrylamide and potassium alginate, with a mass ratio of polyacrylamide to potassium alginate of 8:2. The potassium alginate is used to maintain the strength of the polymer gel film after the acid-producing bacteria begin to produce acid.

[0019] A method for using a composite soil conditioner for mobile sandy soil, comprising the following steps: Step 1: Collect raw materials and crush them into biomass pellets; Step 2: Prepare a polymer solution and add a microbial agent to the polymer solution. Soak the biomass pellets in the polymer solution for 5-10 minutes to make a viscous polymer solution adhere to the surface of the biomass pellets. Step 3: Spread the biomass pellets onto the surface of the shifting sandy soil, then rotary tillage to allow the sandy soil to adhere to the surface of the biomass pellets, forming a sandy soil crust, and then compact the surface layer of the shifting sandy soil.

[0020] Furthermore, in step two, the microbial agent is mixed in in the form of live bacterial liquid or activated powder suspension.

[0021] Furthermore, 1.8-3 tons of compound soil conditioner should be added to each acre of mobile sandy soil.

[0022] Compared with existing technologies, the present invention provides a composite soil conditioner for mobile aeolian sandy soil and its application method, which has the following advantages: In this invention, biomass particles with a polymer gel film on their surface are rolled in flowing sand and soil to quickly form spherical objects encased in sand. These spherical objects are distributed on the surface of the flowing sand and soil, serving an effect similar to a gravel layer (gravel layers are used to suppress moving sand and soil during road construction, but this can prevent subsequent vegetation from growing properly). By suppressing the sand and soil with their own weight, the wind-blown effect is reduced, thus immediately fixing the moving sand and soil without affecting subsequent vegetation growth.

[0023] Subsequently, microorganisms within the polymer gel membrane begin to grow on the sandy soil coating and biomass pellets. Acid-producing bacteria utilize the waste grain powder from the biomass pellets to generate organic acids, which react with the poorly weathered soil minerals. This process rapidly increases the weathering degree of the minerals without causing soil acidification, releasing some of the nutrients from the minerals. Furthermore, the released soluble calcium salts react with potassium alginate to solidify and maintain the strength of the sandy soil coating.

[0024] After the waste grain powder is depleted, the long-lasting organic matter has been decomposed by Trichoderma reesei and white rot fungi, and can be utilized by other microorganisms. In addition, the nutrients released from the minerals in the early stage, as well as the nitrogen-carbon ratio regulated by nitrogen-fixing bacteria, can maintain the growth of engineered bacteria such as biofilm-producing bacteria and phosphorus- and potassium-solubilizing bacteria for a long time. This allows for the continuous production of biofilm to maintain the aggregation of soil particles and the continuous release of nutrients from soil minerals to maintain fertility. This supports vegetation growth to maintain the supply of organic matter and establishes a long-term sustainable soil ecological cycle.

[0025] By combining the above points, and with most materials readily available locally and only a small amount of microbial agents and polymer powder required, the improvement of mobile sandy soil has been achieved. Attached Figure Description

[0026] Figure 1 A flowchart illustrating the changes occurring within the soil during the process of improving soil using a composite soil conditioner for mobile sandy soil and its application method according to the present invention. Detailed Implementation Taking the research project on the mechanism and prevention strategies of various types of soil erosion under complex mountainous conditions, in which this invention is proposed for soil improvement, as an example, this invention is used to treat several mobile sandy soil plots. The microbial agent formula in this embodiment is also used to treat non-mobile sandy soil. Here, in order to treat mobile sandy soil, it has been adjusted and improved, and a structure for sand fixation has been added.

[0027] A composite soil conditioner for mobile sandy soil is used to improve mobile sandy soil in areas with annual precipitation exceeding 400 mm. It employs a high-molecular polymer to initially fix the mobile sandy soil, followed by staged improvement using various microbial agents and agricultural and forestry solid waste. Note that this invention is not applicable to arid regions such as deserts, where there is no water for microbial growth. Furthermore, sand stabilization techniques such as straw checkerboard grids can already be used in these areas.

[0028] Soil conditioners include the following components: Biomass particles serving as carriers and fermentation substrates include dried plant powder, organic fertilizer powder, and oxygen channel organic matter used to prevent oxygen deficiency inside the biomass particles, which are rice husks and / or crushed peanut shells. The main function of dried plant powder is to provide a carbon source, while organic fertilizer powder provides microorganisms with various trace elements and an early nitrogen source. It also helps plant growth later on. The polymer gel and biofilm entering the biomass pellets prevent oxygen from entering the pellets, affecting the growth of various microorganisms (all aerobic bacteria) in this embodiment. Rice husks contain a large amount of phytoliths, and peanut shells are a type of organic matter that is extremely difficult to metabolize; therefore, both can exist in the soil for a long time. Furthermore, because rice husks are hollow and peanut shells are microporous, they provide channels for gas to enter and exit, transferring oxygen to the biofilm.

[0029] The polymer gel film used to form a sandy coating on the surface of biomass pellets is the part left on the surface of the biomass pellets after the biomass pellets are soaked in a polymer solution containing a microbial agent. Here, a polymer gel membrane is used to adhere a layer of sand, thereby increasing the weight of the biomass pellets. Biomass pellets alone are not effective at suppressing wind-blown sand and dust. At the same time, its presence also facilitates the inoculation of microbial agents.

[0030] Sandy soil crusts are used to suppress the flow of wind-blown sand and provide a basis for the growth of microorganisms. The sandy soil crusts are sandy soil layers that are rolled and adhered to by polymer gels in the flowing wind-blown sand. Most microorganisms require a stable substrate for growth, with fungi being particularly reliant on it. However, shifting sandy soil cannot provide this substrate, so a sandy crust is used here. This sandy crust contains various nutrients from the biomass particles and the shifting sandy soil itself, and its loose texture ensures it is not oxygen-deficient. Therefore, it serves as the primary environment for microbial growth.

[0031] The microbial agent contains the following strains: Acid-producing bacteria that enhance the weathering of minerals in the soil; The initial soil contains very low levels of various inorganic salts. Therefore, acid-producing bacteria are needed to first corrode the minerals in the soil particles, increasing the weathering degree of the soil minerals and releasing enough inorganic salts to support the subsequent growth of microorganisms. These inorganic salts are generally not strictly inorganic substances; their anions are usually organic acid radicals (some also release hydrogen phosphate due to pH changes), which can serve as a readily available carbon source for other microorganisms. Their cations include a variety of elements such as sodium, potassium, calcium, iron, and manganese, covering the various trace elements needed for microbial growth (pectin organic matter also contains some, but only enough for acid-producing bacteria), and also includes elements such as phosphorus and potassium that are important for plants. In conventional soils, these organic acids can have some adverse effects. However, in the initial soil, these organic acids are consumed and can even have positive effects.

[0032] Biofilm-producing bacteria used to generate biofilms that aggregate soil particles; This embodiment utilizes physical compression to fix sand in a short time. However, the compression structure itself can be metabolized, so other methods are needed to aggregate soil particles. This embodiment uses biofilm-producing bacteria to achieve this. These bacteria can secrete extracellular polymers to create biofilms, which aggregate soil particles. In addition, acid-producing bacteria secrete organic acids that corrode soil minerals to produce soluble calcium salts. These calcium salts subsequently undergo a series of reactions to become insoluble calcium salts, which also contribute to the aggregation of soil particles.

[0033] Phosphorus- and potassium-solubilizing bacteria used to release insoluble nutrients from minerals; Phosphorus and potassium solubilizing bacteria are commonly used microbial fertilizers that release phosphorus and potassium fertilizers from minerals such as potassium feldspar and apatite (acid-producing bacteria also have some effect, but not as much as phosphorus and potassium solubilizing bacteria). These microbial fertilizers have high soil requirements and are not effective initially. However, after the soil is treated with acid-producing bacteria, the soil contains organic acids and organic acid salts, and soil particles aggregate, allowing these phosphorus and potassium solubilizing bacteria to grow and continuously improve soil fertility.

[0034] Nitrogen-fixing bacteria used to regulate the carbon-to-nitrogen ratio.

[0035] Nitrogen-fixing bacteria are used to regulate the carbon-nitrogen ratio. These bacteria not only provide nitrogen fertilizer for plants after they grow, but more importantly, they regulate the carbon-nitrogen ratio to ensure that various microorganisms do not fail to grow normally due to an imbalance in the carbon-nitrogen ratio in the fermentation substrate (too low nitrogen content in long-lasting organic matter can easily lead to an imbalance in the carbon-nitrogen ratio).

[0036] In this embodiment, the composite soil conditioner is mixed into the top 5-15 cm of soil, and the concentration of each bacterial species in the polymer gel, calculated in CFU, is not less than 2 × 10⁻⁶. 7 CFU / g, total viable bacteria concentration not less than 4×10 8 CFU / g. This ensures that each microorganism quickly reaches the required population size.

[0037] To ensure sufficient compaction, the composite soil conditioner is incorporated into the topsoil as much as possible. This topsoil layer itself has a high concentration of plant roots, making it highly valuable for soil improvement.

[0038] In this embodiment, the acid-producing bacteria include Trichoderma reesei and white-rot fungi used to decompose biomass particles to produce small molecule organic matter including monosaccharides, acetic acid bacteria used to produce acetic acid, and Aspergillus niger used to produce citric acid and gluconic acid to form chelate salts and release small molecule carbon sources that can be utilized by acetic acid bacteria. Acetic acid bacteria and Aspergillus niger can rapidly produce large quantities of organic acids, and most acetates are soluble, thus ensuring the weathering effect on soil minerals. Some acetates are insoluble or even unstable in water (such as aluminum acetate), in which case citric acid and gluconic acid are used to form chelate salts. Acetic acid bacteria require small-molecule organic matter such as glucose and alcohol as carbon sources, which are provided by Aspergillus niger through the decomposition of starch.

[0039] Trichoderma reesei and white-rot fungi can also secrete organic acids, but in smaller quantities. These two fungi are primarily used here to process long-lasting organic matter, breaking it down into smaller molecular weight organic compounds for use by other fungi. White-rot fungi can decompose lignin, while Trichoderma reesei can efficiently decompose cellulose.

[0040] In this embodiment, the film-forming bacteria is Bacillus subtilis, and the phosphorus-solubilizing and potassium-solubilizing bacteria is Bacillus mucilaginosa.

[0041] Bacillus subtilis is a versatile organism with some nitrogen-fixing and phosphorus and potassium-solubilizing abilities, though not strong. Its notable ability is its efficient secretion of extracellular polymeric substances (EPS), rapidly generating biofilms to aggregate soil particles. This ability to produce EPS can be observed in everyday life, such as in natto, a sticky soybean product made using Bacillus subtilis fermentation. Meanwhile, Bacillus mucilaginosus possesses a strong ability to decompose minerals to produce soluble potassium salts, and also exhibits considerable phosphorus-solubilizing capabilities.

[0042] Considering the metabolic status, efficacy stages, and synergistic effects of different microbial species, and based on calculations and multiple experiments, the following are relatively effective microbial ratios. The proportions of each microbial species in the compound soil conditioner, calculated in CFU, are shown in the table below: Table 1: Range of Proportions of Various Microbial Species in Composite Soil Conditioner The proportions of each bacterial species in the bacterial agent, calculated in CFU, are as follows: These ranges are taken into account that it is impossible to achieve perfect precision when mixing different strains, but as long as they are within these ranges, they can achieve good soil improvement effects. At the same time, compared with the bacterial agent formula used to improve non-mobile sandy soil, the proportion of acetic acid bacteria is reduced here because the raw materials lack small molecule carbon sources that can be directly utilized by acetic acid bacteria and must be released by other strains through metabolism.

[0043] In this embodiment, the dried plant powder includes starchy organic matter used to provide carbon source for Aspergillus niger and acetic acid bacteria in the early stage, and long-lasting organic matter used to provide carbon source for a long time in the later stage; the starchy organic matter is waste grain powder including aged grain powder and dried distiller's grains powder, and the long-lasting organic matter is lignified plant stem powder and / or mature plant stem powder. Since acid production is needed to increase the differentiation of soil minerals, a carbon source that can be utilized by acid-producing bacteria from the outset is required. At the same time, this carbon source needs to be able to be mixed into biomass pellets and should be as inexpensive as possible. Considering these factors, waste grain powder is a good choice. Alternatively, dried tuber powder or waste starch can also be used. In autumn, grasses with seeds can be crushed and used as dried plant powder, which contains long-lasting organic matter and starchy organic matter like grass seed powder.

[0044] As for long-lasting organic matter, there is a wide variety of options available, including slow-degrading organic matter such as hay powder, straw powder, and crushed logging residues. Organic fertilizer powder can be made by drying and grinding various types of well-rotted manure.

[0045] In this embodiment, the mass ratio of waste grain powder, long-lasting organic matter, organic fertilizer powder, and oxygen-channel organic matter is 5-10:15-20:80:5. This formula can effectively balance the nutrients required by microorganisms at different stages.

[0046] The polymer solution is a mixture of polyacrylamide and potassium alginate, with a mass ratio of 8:2. Potassium alginate is used to maintain the strength of the polymer gel film after the acid-producing bacteria begin to produce acid.

[0047] The polyacrylamide gel membrane here will gradually thin and eventually disappear due to microbial metabolism. This process can lead to the collapse of the sandy soil crust. To avoid this, potassium alginate is added. After acid-producing bacteria begin to produce acid, creatine will react with minerals in the soil to form various soluble calcium salts, such as calcium acetate. These calcium salts react with potassium alginate to form a high-strength calcium alginate gel. At the same time, the cations in potassium alginate can be utilized by plants. Note that sodium alginate should not be used, as sodium ions will increase the soil salinity to some extent.

[0048] A method for using a composite soil conditioner for mobile sandy soil, comprising the following steps: Step 1: Collect raw materials and crush them into biomass pellets; Step 2: Prepare a polymer solution and add a microbial agent to the polymer solution. Soak the biomass pellets in the polymer solution for 5-10 minutes to make a viscous polymer solution adhere to the surface of the biomass pellets. Do not soak for too long, otherwise the biomass pellets will become loose. Soak for 5 to 10 minutes to allow the surface to absorb a layer of mucus and for the mucus to penetrate 1 to 2 millimeters into the surface of the biomass pellets.

[0049] Step 3: Spread the biomass pellets onto the surface of the shifting sandy soil, then rotary tillage to allow sand to adhere to the surface of the biomass pellets, forming a sandy crust. Finally, compact the surface layer of the shifting sandy soil. If there has been no recent rainfall, it is best to spray water to moisten the surface layer of the sandy soil after compaction.

[0050] When rotary tilling, the depth should be controlled to ensure that the biomass particles are located in the soil surface layer to maximize the compaction effect.

[0051] In step two, the microbial agent is mixed in as a live bacterial solution or an activated powder suspension.

[0052] In this embodiment, 1.8-3 tons of compound soil conditioner are added per acre of mobile sandy soil. The specific dosage should ensure that at least 40% of the soil surface is covered when sowing in step three.

[0053] This invention is intended for the improvement of wind-blown sandy soil in Pai Town, Milin County, Nyingchi City. In local sample plots, 7 kg of compound soil conditioner was added to every 50 kg of topsoil. The proportions of various microorganisms in the compound soil conditioner were within the ranges shown in Table 1. From April 10, 2025 to June 10, 2025, the flow of topsoil and vegetation growth in the sample plots were continuously monitored. The results showed that this embodiment effectively inhibited the flow of wind-blown sandy soil, preventing it from being blown away by the wind. Furthermore, plants subsequently sown on the surface grew normally, with growth levels equivalent to those under conventional fertilization treatments. The experimental results demonstrate that this invention can effectively improve the soil.

[0054] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A composite soil conditioner for mobile aeolian soil, used to improve mobile aeolian soil in areas with annual precipitation exceeding 400 mm, characterized in that: High molecular polymers are used to initially fix the mobile sandy soil, and then various microbial agents and agricultural and forestry solid wastes are used to improve the sandy soil in stages. The soil conditioner comprises the following components: The biomass particles used as carriers and fermentation substrates are dried plant powder, organic fertilizer powder, and oxygen channel organic matter used to prevent oxygen deficiency inside the biomass particles, wherein the oxygen channel organic matter is rice husk and / or crushed peanut shells. The polymer gel film used to form a sandy coating on the surface of biomass particles is the part remaining on the surface of the biomass particles after the biomass particles are soaked in a polymer solution containing a microbial agent. Sandy soil coatings are used to suppress the flow of wind-blown sand and provide a basis for the growth of microorganisms. The sandy soil coatings are sandy soil layers in which a polymer gel rolls and adheres in the flowing wind-blown sand. The microbial agent contains the following microbial strains: Acid-producing bacteria that enhance the weathering of minerals in the soil; Biofilm-producing bacteria used to generate biofilms that aggregate soil particles; Phosphorus- and potassium-solubilizing bacteria used to release insoluble nutrients from minerals; Nitrogen-fixing bacteria used to regulate the carbon-to-nitrogen ratio.

2. The composite soil conditioner for mobile aeolian sandy soil according to claim 1, characterized in that: The composite soil conditioner is mixed into the top 5-15 cm of soil, and the concentration of each bacterial species in the polymer gel, calculated in CFU, is not less than 2 × 10⁻⁶. 7 CFU / g, total viable bacteria concentration not less than 4×10 8 CFU / g.

3. The composite soil conditioner for mobile aeolian sandy soil according to claim 2, characterized in that: The acid-producing bacteria include Trichoderma reesei and white-rot fungi used to decompose biomass particles to produce small-molecule organic matter, including monosaccharides; acetic acid bacteria used to produce acetic acid; and Aspergillus niger used to produce citric acid and gluconic acid to form chelate salts and release small-molecule carbon sources that can be utilized by acetic acid bacteria. The nitrogen-fixing bacteria include Azotobacter chrysotrichum, which is used to regulate the carbon-nitrogen ratio before vegetation grows, and Rhizobium and Freundii, which are used to regulate the carbon-nitrogen ratio after vegetation grows. The film-forming bacteria is Bacillus subtilis, and the phosphorus-solubilizing and potassium-solubilizing bacteria is Bacillus mucilaginosus.

4. A composite soil conditioner for mobile aeolian sandy soil according to claim 3, characterized in that: The dried plant powder includes starchy organic matter used to provide carbon source for Aspergillus niger and acetic acid bacteria in the early stage, and long-lasting organic matter used to provide carbon source for a long time in the later stage; the starchy organic matter is waste grain powder including aged grain powder and dried distiller's grains powder, and the long-lasting organic matter is lignified plant stem powder and / or mature plant stem powder. The mass ratio of the waste grain powder, long-lasting organic matter, organic fertilizer powder, and oxygen channel organic matter is 5-10:15-20:80:

5.

5. A composite soil conditioner for mobile aeolian sandy soil according to claim 3, characterized in that: The proportions of each bacterial species in the bacterial agent, calculated in CFU, are as follows: Acid-producing bacteria: 50-60% in total, of which: Trichoderma reesei: 15-21%; White rot fungi: 10-14%; Acetic acid bacteria: 5-10%; Aspergillus niger: 15-20%; Nitrogen-fixing bacteria: 25-30% in total, of which: Azotocinus chrysophytes: 15-20%; Rhizobium + Freundii: 5-10%; Film-forming bacteria: 5-10% in total, of which: Bacillus subtilis 5-10%; Phosphorus- and potassium-solubilizing bacteria: Total 5-10%, of which: 5-10% of Bacillus jellyii.

6. A composite soil conditioner for mobile aeolian sandy soil according to claim 1, characterized in that: The polymer solution is a mixture of polyacrylamide and potassium alginate, with a mass ratio of 8:

2. The potassium alginate is used to maintain the strength of the polymer gel film after the acid-producing bacteria begin to produce acid.

7. A method for using a composite soil conditioner for mobile aeolian sandy soil, characterized in that: The method of improving soil using a composite soil conditioner for mobile aeolian sandy soil as described in claim 3 includes the following steps: Step 1: Collect raw materials and crush them into biomass pellets; Step 2: Prepare a polymer solution and add a microbial agent to the polymer solution. Soak the biomass pellets in the polymer solution for 5-10 minutes to make a viscous polymer solution adhere to the surface of the biomass pellets. Step 3: Spread the biomass pellets onto the surface of the shifting sandy soil, then rotary tillage to allow the sandy soil to adhere to the surface of the biomass pellets, forming a sandy soil crust, and then compact the surface layer of the shifting sandy soil.

8. The method of using a composite soil conditioner for mobile aeolian sandy soil according to claim 7, characterized in that: In step two, the microbial agent is mixed in as a live bacterial solution or an activated powder suspension.

9. The method of using a composite soil conditioner for mobile aeolian sandy soil according to claim 7, characterized in that: Use 1.8-3 tons of compound soil conditioner per acre of mobile sandy soil.

Images