Soil micro-ecological restoration liquid complex microbial inoculant suitable for hillside dry land and biological bacterial fertilizer thereof

Abstract

The invention relates to the field of microbial agents, in particular to a soil micro-ecological restoration liquid composite microbial agent and biological bacterial fertilizer suitable for hillside dry land. The soil micro-ecological restoration liquid complex microbial inoculant suitable for the hillside dry land comprises nitrogen-fixing bacteria: azotobacter chroococcum ACCC 11104, phosphate solubilizing bacteria: pseudomonas fluorescens ACCC 03031, potassium solubilizing bacteria: bacillus mucilaginosus CCTCC KB20082790, growth-promoting bacteria: azospirillum brazil CCTCC AB 91001, bacillus subtilis CGMCC 17161, synergistic bacteria: trichoderma asperellum CGMCC 3.17461, and drought-resistant bacteria: bacillus megatherium ACCC 11099 and streptomyces CCTCC KA 2008039. The biological bacterial fertilizer for the hillside dry land is prepared from the liquid complex microbial inoculant, and compared with a conventional biological bacterial fertilizer, the biological bacterial fertilizer has the advantages that the ecological adaptability to the hillside dry land is greatly improved, the hillside dry land is effectively improved, and the crop yield is remarkably increased.

Description

Technical Field

[0001] This invention relates to the field of microbial agents, specifically to liquid compound microbial agents and bio-fertilizers suitable for soil microecological restoration in dry hillsides. Background Technology

[0002] Dryland slopes are important production areas for corn, potatoes, miscellaneous grains, beans, and oilseed crops, directly contributing to considerable grain yields. For tens of millions of farmers, especially in the central and western regions, dryland slopes are the most basic means of production and a guarantee of survival; abandoning the land is tantamount to abandoning their livelihood. Dryland slopes are also the cradle of specialty agricultural products; many well-known geographical indication products, such as Yunnan Pu'er tea, Shaanxi Luochuan apples, and Shanxi Qinshui yellow millet, all originate from dryland slopes. Moreover, the utilization of dryland slopes is directly related to soil erosion; the scientific and rational use of dryland slopes (such as terracing and conservation tillage) is itself one of the most important ecological protection measures.

[0003] Low yield is the most pressing problem to be solved in developing agriculture on dry slopes, mainly due to the characteristics of dry slopes being arid and water-scarce, with poor soil storage capacity and soil calcification. Directly applying ordinary chemical fertilizers to dry slopes not only results in low utilization rates but also triggers a series of serious negative effects: ordinary fertilizers have high soluble salt content, which cannot be diluted in a water-scarce environment, leading to a sharp increase in the osmotic pressure of the rhizosphere soil solution. This not only causes seedling burn and salt damage but also severely inhibits seed germination; ordinary fertilizers also accelerate the decomposition and consumption of organic matter in the soil and damage the soil's aggregate structure, further hardening and compacting the already poorly stored and loose soil, reducing aeration and further impairing drought resistance and moisture retention, creating a vicious cycle; the use of ordinary fertilizers is equivalent to adding a large number of salt ions (such as NH4+) to the soil. 4+ K + Cl — NO 3— However, under conditions of severe water shortage and strong evaporation in dry hillsides, these salts cannot be leached out and will continue to accumulate on the soil surface, leading to secondary salinization, which further deteriorates the already alkaline calcareous soil environment and severely inhibits crop growth.

[0004] In recent years, improving the soil microecological environment and increasing crop yield through microbial inoculants has become a research and application hotspot. Therefore, developing a microbial inoculant suitable for dry mountain slopes to improve crop yield and soil properties has become a current research focus. Although some microbial inoculants have been applied to dry mountain slopes in existing technologies, their effects are still unsatisfactory, with many problems: water scarcity in dry mountain slopes directly inhibits microbial activity, spore germination, and the diffusion of nutrients and metabolites; high temperatures and strong ultraviolet radiation cause microbial cell damage, protein denaturation, and DNA destruction. Drought and water scarcity also lead to soil structure damage, increased risk of salinization, and nutrient depletion, further worsening the microbial living environment. Furthermore, introduced microbial inoculants must compete fiercely for resources and space with native microorganisms adapted to harsh environments, while drought stress restricts plant root development and alters physiological states, hindering effective interaction between plants and beneficial microorganisms. These combined factors make the effects of single or simply combined microbial agents extremely unstable and unpredictable, making it difficult to solve the problems of drought and water shortage, poor soil storage capacity, and soil calcification in dry hillsides, and failing to adapt to the characteristics of dry hillsides.

[0005] Compared to single-strain or simple combinations of microbial agents, compound microbial agents have the core advantage of enhancing functionality, improving environmental adaptability, increasing the stability of effects, and providing more comprehensive functions through the synergistic effect of the microbial community. However, the preparation of compound microbial agents is difficult. Fermenting different strains separately leads to numerous production equipment and difficulties in production control. While mixed or partially mixed fermentation can reduce production equipment, various factors such as unbalanced culture medium composition, conditions more suitable for the growth of certain strains, different effects of fermentation conditions (temperature, pH, dissolved oxygen, etc.) on different strains, and the production of substances by some strains that inhibit the growth of other strains (e.g., antibiotics) can cause some strains to grow too quickly in an environment where multiple microorganisms coexist. This can lead to the loss of the synergistic effect of the compound microorganisms and even the production of adverse metabolites, such as odor substances, toxins, and pigments, affecting product quality and safety.

[0006] Therefore, the industrial production of compound microbial agents faces significant challenges, including problems such as microbial community imbalance, functional failure or weakening, low yield, and difficulty in controlling product quality during large-scale industrial production. Existing technologies offer several solutions, such as optimizing the culture medium: adjusting the proportions of carbon sources, nitrogen sources, and trace elements to meet the growth needs of different strains and avoid excessive abundance of a single nutrient; optimizing fermentation conditions: controlling temperature, pH, stirring rate, and aeration to promote the overall growth of the compound microorganisms and inhibit the excessive growth of dominant strains; strain domestication: through multiple consecutive subculturing, allowing strains to adapt to specific fermentation environments and improving their tolerance and competitiveness; controlling the proportion of strains and inoculum size: optimizing the inoculum ratio of each strain to ensure the diversity and balance of the initial microbial community; and using selective inhibitors: adding low concentrations of selective inhibitors to the culture medium to inhibit the growth of dominant strains and maintain microbial community balance. However, these methods do not address how to better suit industrial production, thus employing relatively simplistic approaches that fail to comprehensively optimize various conditions while considering the complex characteristics of each strain. Meanwhile, existing compound microbial agents suitable for dry hillsides still suffer from problems such as unstable efficacy, short shelf life, and large application rates after fertilization. Summary of the Invention

[0007] To address the low crop yields caused by drought, water scarcity, poor soil storage capacity, and soil calcification in dry mountain slopes, the ineffectiveness of conventional fertilizers and their potential to further deteriorate soil properties, and the limitations of existing single or compound microbial agents in meeting the needs of dry mountain slopes, the industrial preparation of compound microbial agents is prone to problems such as microbial imbalance, low yield, and difficulty in controlling product quality to optimize various conditions. This invention provides a liquid compound microbial agent and bio-fertilizer suitable for soil microecological restoration in dry mountain slopes, solving the above-mentioned problems.

[0008] The technical solution of the present invention is as follows:

[0009] This invention provides a liquid compound microbial agent for soil microecological restoration suitable for dry hillsides, characterized by comprising the following eight functional bacterial strains prepared by electrochemical low-Hertz water through three-stage sequential inoculation and fermentation: nitrogen-fixing bacteria: Azotobacter chroococcum, phosphate-solubilizing bacteria: Pseudomonas fluorescens, potassium-solubilizing bacteria: Paenibacillus mucilaginosus, growth-promoting bacteria: Azospirillum brasilense, biocontrol bacteria: Bacillus subtilis, synergistic bacteria: Trichoderma asperellum, and drought-resistant bacteria: Bacillus megaterium and Streptomyces sp.

[0010] S1: Propagation of nitrogen-fixing bacteria, growth-promoting bacteria and drought-resistant bacteria: Add electrolytic low-hertz water to the sterilized main fermenter, and add pre-mixed seed liquid of *Azotobacter spp.*, *Azotobacter brasiliensis*, and *Bacillus megaterium*. Adjust the fermentation conditions to the first-order fermentation conditions: pH=7.0, dissolved oxygen 25-35%, temperature 30℃, humidity of the top space of the fermenter 92%±1%, fermentation time 22-24 hours;

[0011] S2: Introduce phosphate-solubilizing bacteria, biocontrol bacteria, and drought-resistant bacteria to relieve phosphorus limitation: After the S1 stage, adjust to the second sequential fermentation conditions, and add pre-mixed seed liquid of Pseudomonas fluorescens, Bacillus subtilis, and Streptomyces to the main fermenter. The second sequential fermentation conditions are: pH=6.5, dissolved oxygen 35-45%, temperature 30℃, humidity of the top space of the fermenter 92%±1%, and fermentation time 16-18 hours.

[0012] S3: Initiate the synergistic metabolism of potassium-solubilizing bacteria and Trichoderma to activate mineral decomposition: After the fermentation of the S2 stage, add Bacillus mucilaginosus seed liquid to the main fermenter. After fermentation for 12 hours, add Trichoderma echinococcosis seed liquid, turn on mechanical stirring and adjust to the third-sequence fermentation conditions: pH=5.5, dissolved oxygen 45-55%, temperature 28℃, humidity of the top space of the fermenter 88%±1%, fermentation for 34-36 hours;

[0013] When the number of viable bacteria in the main fermenter is ≥2×10 10 Fermentation ends when CFU / mL is reached.

[0014] Preferably, the ratio of nitrogen-fixing bacteria: phosphorus-solubilizing bacteria: potassium-solubilizing bacteria: growth-promoting bacteria: biocontrol bacteria: synergistic bacteria: drought-resistant bacteria is 3:1:1:2:1:1:2, wherein the internal ratio of drought-resistant bacteria is Bacillus megaterium: Streptomyces = 1.2:0.8.

[0015] Preferably, the seed culture preparation method is as follows: seven types of functional strains are inoculated from the preservation slant into a special slant culture medium and cultured at 30℃ for 24-48 hours until the logarithmic growth phase (OD2). 600 When the concentration was ≥1.0, the samples were transferred to shake flasks for culture, and then transferred to seven primary seed tanks for independent culture.

[0016] The method for preparing the pre-mixed seed solution is as follows: when the bacterial count in the primary seed tank is ≥5×10⁻⁶... 8 When CFU / mL, the seed cultures of *Azotobacter chrysogenum*, *Azotobacter brasiliensis*, and *Bacillus megaterium* were mixed at a volume ratio of 1:1:0.5 to obtain premixed seed culture 1. The seed cultures of *Pseudomonas fluorescens*, *Bacillus subtilis*, and *Streptomyces* were mixed at a volume ratio of 1:1:0.3 to obtain premixed seed culture 2. After incubation at 30°C for 30 minutes, the two premixed seed cultures were used for sequential fermentation.

[0017] When the number of Bacillus subtilis bacteria in the primary seed tank is ≥5×10 8 At CFU / mL, the number of Trichoderma acicularis spores is ≥1×10⁻⁶. 7 At a concentration of spores / mL, it can be used for sequential fermentation;

[0018] The nitrogen-fixing bacteria and growth-promoting bacteria are prepared using Assoube medium, the phosphate-solubilizing bacteria are prepared using KB medium, the biocontrol bacteria and drought-resistant bacteria are prepared using LB medium, the potassium-solubilizing bacteria are prepared using potassium-solubilizing medium, and Trichoderma acicularis is prepared using PDA medium; all five media are prepared using electrochemical low-hertz water.

[0019] The inoculation amounts of the premixed seed liquid 1, premixed seed liquid 2, Bacillus mucilaginosus seed liquid, and Trichoderma echinosporum seed liquid are 9.8%-10.2%, 4.8%-5.2%, 4.8%-5.2%, and 2.8%-3.2% of the fermentation volume, respectively. The inoculation amount of electrochemical low-Hertz water is 76.4%-77.6% of the fermentation volume. The electrochemical low-Hertz water has a molecular cluster of ≤6 molecules and a pH of 7.0–7.5.

[0020] Preferably, during the S1 stage, when fermentation reaches the middle of the logarithmic growth phase, growth factors succinic acid and sodium molybdate are added; after the S2 stage fermentation ends and the system pH stabilizes at 6.6-7.0, growth factors glycerol and calcium phosphate are added; when the S3 stage is started, growth factors potassium feldspar powder and chitin powder are added.

[0021] Preferably, succinic acid and sodium molybdate in S1 are added simultaneously and in batches using a pulsed slow-flow injection method. The concentration of succinic acid is 0.01%, and the concentration of sodium molybdate is 10 μM. The addition is done in three batches, with each batch containing 1 / 3 of the total required amount, and the interval between batches is 2 hours.

[0022] The glycerol concentration in S2 is 5 mM, and it is added continuously at a flow rate of 0.5 g / L·h to avoid local concentrations exceeding 10 mM; the calcium phosphate concentration is 2 g / L, added in 3 portions, each portion being 1 / 3 of the total required amount, with an interval of 4 hours.

[0023] The potassium feldspar powder in S3 is added in two batches. The potassium feldspar powder has a particle size of 200 mesh and a concentration of 10 g / L. The two additions are 6 hours apart.

[0024] The present invention also provides a soil micro-ecological restoration bio-fertilizer suitable for dry hillsides, which is prepared using the above-mentioned liquid compound microbial agent for soil micro-ecological restoration suitable for dry hillsides.

[0025] Preferably, the preparation method includes:

[0026] A1: The above-mentioned liquid compound microbial agent, electrochemical low-hertz water, and solid components: lignite powder, wheat bran, and soybean meal are added to the mixing and stirring system. After being mixed evenly, the mixture is conveyed to the solid-state fermentation system production line through an intelligent material distribution system (patent authorization announcement number CN 116553963B) for the first solid-state fermentation. The solid-state fermentation system automatically adjusts the temperature during the fermentation process through a temperature sensor linked to the intermittent micro-burst oxygen frequency: the initial stage temperature is 42-45℃, maintained for 22-24 hours; the peak stage temperature is 60-65℃, maintained for 46-48 hours; and the final stage temperature is 40-45℃, maintained for 22-24 hours.

[0027] A2: The material obtained from the first solid-state fermentation in A1 is rearranged into the aging and fermentation production line through an intelligent material distribution system for a second aging and fermentation: the naturally piled material is deeply decomposed using the residual heat and residual microorganisms. After 10-12 days, the fermentation ends, and the soil micro-ecological restoration bio-fertilizer suitable for dry hillsides is obtained.

[0028] Preferably, the total amount of solid components in A1—lignite powder, wheat bran, and soybean meal—is 100%, with the following proportions: lignite powder 70-85%, wheat bran 8-15%, and soybean meal 8-20%. The lignite powder has a particle size of 80-100 mesh and an initial moisture content of 10-15%, while the initial moisture content of the wheat bran and soybean meal is 8-12%. After the solid components are mixed evenly, electrochemical low-hertz water is added and stirred thoroughly. Simultaneously, a liquid compound microbial agent is added during the stirring process, with the addition amount calculated at 0.8-10% of the total solid components, so that the total moisture content of the material reaches 50-60%.

[0029] Preferably, the sign that the first fermentation of stage A1 has ended is: the temperature is maintained at the final stage temperature for 24 consecutive hours, the material humidity is ≤40%, the material color is dark brown, there is no odor, it is loose when squeezed, and there is no sticking.

[0030] Preferably, the completion of the second fermentation in stage A2 is indicated by the following: when the material naturally cools to a moisture content of 15-29%, has a uniform dark brown color, a loose texture, an earthy smell without other off-odors, a pH of 6.5-7.5, and a beneficial viable bacteria count ≥2×10⁻⁶. 10 When the concentration reaches / g, the second fermentation ends.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention provides a microecological restoration liquid compound microbial agent suitable for dry hillsides. Through the design of grouping and sequential fermentation in the main tank, it organically combines strains with different fermentation conditions that are mutually generative within the same time sequence and metabolically complementary between different time sequences. By designing the fermentation conditions for each time sequence, it ensures that eight functional bacteria can reproduce normally and perform their respective functions, solving the problem of low crop yields caused by drought, poor soil storage capacity, and soil calcification in dry hillsides. Bacillus megaterium and Streptomyces secrete a large amount of extracellular polysaccharides and hydrophobic proteins, effectively cementing soil particles and improving soil water holding capacity. Azotobacter brasiliensis secretes auxin to stimulate deep root expansion of crops and enhance the water absorption range. The two work together to construct a soil-root system that integrates water use for high efficiency, solving the problem of drought and water shortage in dry hillsides. The well-developed hyphal network of *Trichoderma echinosporum* and the biofilm produced by *Bacillus subtilis* together weave an organic framework, promoting the formation of stable aggregates and significantly increasing soil porosity. Humic substances produced by *Azotobacter globosum* further enhance aggregate stability, expand soil nutrient storage space, fundamentally improve the physical structure of shallow and infertile soils, and solve the problem of poor soil storage capacity in hillside drylands. *Pseudomonas fluorescens* secretes organic acids such as citric acid and gluconic acid, efficiently dissolving the calcium carbonate cementing layer in the soil and releasing fixed phosphorus. *Bacillus mucilaginosus* simultaneously releases silicate enzymes to hydrolyze potassium and decompose clay minerals, synergistically breaking down the calcium barrier with phosphate-solubilizing bacteria. Meanwhile, acidic substances produced by *Streptomyces* help neutralize soil alkalinity, resolving the inhibition of nutrient availability by calcification through multiple pathways and solving the problem of calcification in hillside drylands. By designing the main tank for grouped and sequential fermentation, eight functional bacteria are cultured together. This allows the liquid compound microbial agent to not only have basic growth-promoting functions but also drought-resistant functions, making it highly adaptable to dry hillsides. This solves the problem that Bacillus subtilis alone cannot survive in the harsh environment of dry hillsides. Furthermore, the industrial production of liquid compound microbial agents, which involves culturing eight functional bacteria together, results in Bacillus megaterium and Bacillus subtilis having excessive growth capabilities, inhibiting the growth of other functional bacteria, leading to an imbalance of microbial communities, metabolic disorders, and fermentation failure within the fermenter.

[0033] This invention groups eight functional bacteria according to their growth requirements and performs time-sequential culture:

[0034] The first inoculation sequence includes *Bacillus megaterium*, *Azotobacter chrysogenum*, and *Azotobacter brasiliensis*, all of which are Gram-positive and Gram-negative bacteria with both nitrogen-fixing and growth-promoting functions, and prefer a neutral, slightly aerobic environment. This invention sets the fermentation conditions as follows: dissolved oxygen 20-30% to match the nitrogenase activity's preference for a low-oxygen environment, while also meeting the basic metabolic needs of the bacteria; pH 7.0 to provide the optimal acid-base environment for nitrogen fixation by *Azotobacter chrysogenum* and extracellular polysaccharide synthesis by *Bacillus megaterium*; and constant-temperature fermentation at 30°C for 22-24 hours to balance the proliferation rate and metabolic activity of the three bacteria, avoiding high-temperature inhibition of nitrogenase synthesis. Maintaining a high humidity of 92% at the top of the fermenter effectively reduces fermentation broth evaporation, providing a stable osmotic environment for *Azotobacter chrysogenum* and *Azotobacter brasiliensis*, preventing cell membrane damage due to dehydration and ensuring nitrogenase synthesis and growth hormone secretion; simultaneously meeting the high water requirements of *Bacillus megaterium* during the secretion of extracellular polysaccharides and hydrophobic proteins, promoting the efficient accumulation of drought-resistant substances. The mixed fermentation of these three bacteria produces a significant synergistic effect: *Azotobacter chamaecyparis* and *Azospirillum brasiliensis* jointly fix nitrogen, continuously providing an organic nitrogen source for the system, which is directly utilized by *Bacillus megaterium* to synthesize water-retaining polysaccharides and biofilms; the growth-promoting substances secreted by *Bacillus megaterium* can in turn stimulate the proliferation of the other two bacteria and increase their nitrogen-fixing efficiency. This simultaneous fermentation strategy not only simplifies the process but also constructs a self-trophic system of microaerobic nitrogen fixation and growth-promoting substance synthesis through microbial interactions, laying the foundation for the subsequent function of the microbial agents. Delaying this stage would disrupt the dynamic balance between nitrogen fixation and nitrogen source consumption, leading to the accumulation of metabolites that inhibit cell growth.

[0035] The second-order inoculation involves *Pseudomonas fluorescens*, *Bacillus subtilis*, and *Streptomyces*, all of which are fast-growing microorganisms that prefer a slightly acidic environment and have high oxygen consumption during metabolism (especially during spore formation and secondary metabolite synthesis). This invention sets the second-order fermentation conditions as follows: dissolved oxygen 35–45% to fully support the high-aerobic metabolism of the three bacteria; pH 6.5 to effectively activate the organic acid synthesis pathway of *Pseudomonas fluorescens* and the antimicrobial substance production of *Bacillus subtilis*, while simultaneously promoting the secretion of hydrophobic proteins and extracellular polysaccharides by *Streptomyces*; and constant-temperature fermentation at 30°C for 16–18 hours to maintain metabolic activity while achieving rapid cell proliferation and functional product accumulation. Maintaining a 92% humidity level at the top of the fermenter effectively supports the vigorous metabolism of *Pseudomonas fluorescens* in secreting organic acids, *Bacillus subtilis* in synthesizing antimicrobial peptides, and *Streptomyces* in secondary metabolism, preventing enzyme activity decline or metabolic pathway obstruction due to moisture loss. Furthermore, all three fermentation processes rely on the nitrogen source provided by the first-order nitrogen-fixing bacteria and growth-promoting bacteria to synthesize key metabolic enzymes, thereby efficiently utilizing the nitrogen nutrients accumulated in the early stages. The activated phosphorus and stress-resistance substances produced by their metabolism can provide nutrition and microecological support for the synergistic growth of the third-order potassium-solubilizing bacteria and Trichoderma. If the fermentation sequence is advanced or dissolved oxygen is insufficient in this stage, it will lead to a decrease in phosphorus activation efficiency and hinder the synthesis of stress-resistance substances, affecting the synergistic effect of the subsequent microbial community.

[0036] In the third time sequence, after inoculating the Bacillus mucilaginosus seed culture into the main fermenter, the Trichoderma echinococcus seed culture was inoculated 12 hours later. Bacillus mucilaginosus is a typical phosphate-solubilizing and potassium-solubilizing bacterium with acid-resistant metabolic characteristics; Trichoderma echinococcus is a strictly aerobic fungus, requiring a high-oxygen environment for sporulation, and the growth rates of the two differ significantly (the growth rate of Trichoderma echinococcus is significantly lower than that of Bacillus mucilaginosus). This invention, through a 12-hour delay in inoculation of Trichoderma echinococcus, effectively avoids the competitive inhibition of rapid bacterial proliferation on the initial growth of the fungus. Simultaneously, the chitinase secreted by Trichoderma echinococcus can regulate the population density of potential contaminants (including chitinous cell wall microorganisms) in the fermentation system, maintaining the stability of the microbial community structure and laying the foundation for the synergistic metabolism of functional strains. The third fermentation parameters were precisely set according to the synergistic metabolic needs of the two strains: dissolved oxygen concentration was controlled at 60%, which fully met the strict aerobic sporulation and metabolic requirements of *Trichoderma echinococcosis*, while also adapting to the aerobic metabolic characteristics of *Bacillus mucilaginosus*; pH was adjusted to 5.5, which was suitable for the optimal acidic environment for enzyme production in *Trichoderma echinococcosis*, while also being compatible with the acid-resistant characteristics of *Bacillus mucilaginosus*; fermentation temperature was maintained at 28℃, a temperature range that could simultaneously meet the optimal growth requirements of both functional strains, ensuring the stable expression of functional genes during long-term fermentation. In this stage, the humidity in the top space of the fermenter was controlled to 88%±1% (precisely controlling the humidity fluctuation range). On the one hand, this moderately promoted the differentiation of aerial mycelia and spore formation in *Trichoderma echinococcosis*, and the low humidity environment stimulated the production of stress-resistant spores, significantly improving the survival and colonization ability of the inoculum in drought-stressed soil environments; on the other hand, it prevented excessive humidity from causing excessive entanglement and aggregation of fungal mycelia, ensuring the uniformity of the fermentation broth and oxygen transfer efficiency, providing a favorable environment for the proliferation and metabolism of *Bacillus mucilaginosus*. Furthermore, the growth and functional expression of Bacillus mucilaginosus and Trichoderma echinococcosis are highly dependent on the microenvironment and material basis constructed by the second-order bacterial community: ① Bacillus mucilaginosus can efficiently utilize the soluble phosphorus source activated by the second-order Pseudomonas fluorescens to synthesize a specific silicate enzyme system, thereby promoting the release of insoluble potassium in the soil; at the same time, the organic acids secreted during its metabolism can further optimize the pH microenvironment of the fermentation broth, providing a suitable initial growth environment for Trichoderma echinococcosis, which prefers weakly acidic conditions; ② Trichoderma echinococcosis can utilize the amino acids, trace elements and other nutrients produced by the metabolism of Bacillus mucilaginosus and the second-order functional bacterial community as carbon and nitrogen source support for spore germination and hyphal expansion. Its well-developed hyphal network can also provide physical colonization sites for Bacillus mucilaginosus in the fermentation system during the extension process, forming a "bacteria-fungus" synergistic symbiotic microecological structure and strengthening the functional complementary effect.

[0037] The three groupings and corresponding time sequences designed in this invention are scientifically efficient, ensuring no interspecies antagonism during the fermentation process of each strain, that their own propagation is not inhibited, and that the fermentation products of strains propagating earlier do not adversely affect strains propagating later, allowing them to be efficiently utilized by strains propagating later to promote growth. Furthermore, due to the rational design, the secondary propagation process of the liquid compound microbial agent (i.e., the time-sequential propagation in the main fermenter) only requires the addition of trace amounts of growth factors and electrolytic low-hertz water, eliminating the need for additional carbon and nitrogen sources, thus simplifying the production process. In addition, the secondary fermentation of this invention only requires the use of a single independent main fermenter, avoiding idle tanks, reducing the probability of cross-contamination, and effectively lowering production costs.

[0038] In the preparation of the liquid compound microbial agent, electrochemical low-Hertz water is used for humidity control in the top space of the fermenter, inoculum activation, primary culture, and time-sequential culture in the main fermenter. This electrochemical low-Hertz water consists of six water molecules, has a permeability more than 30% higher than ordinary water, strong dissolving power, and can quickly pass through cell membrane water channels (only 0.5 nanometers in diameter), carrying nutrients into cells and accelerating the excretion of metabolic waste. Simultaneously, electrochemical low-Hertz water can also enhance the permeability of microbial cell membranes, promote the transmission of intercellular signaling molecules (such as quorum sensing substances), and optimize the metabolic network of the compound microbial community. The small-cluster water is weakly alkaline (pH 7.5-8.0), which can neutralize acidic metabolites (such as lactic acid and acetic acid) produced during fermentation, maintaining the optimal pH environment for enzymatic reactions. In phosphate-solubilizing bacteria fermentation, electrochemical low-Hertz water can stabilize the pH of the fermentation broth at 6.5-7.0, increase acid phosphatase activity, and thus improve phosphorus solubility. In addition, electrochemical low-hertz water promotes the reproduction and nitrogenase activity of *Azotobacter chamaescoparia* by providing a highly active carbon source and optimizing the carbon-nitrogen ratio, thus establishing a nitrogen source basis; it relieves phosphorus limitation by promoting the secretion of organic acids (such as gluconic acid and citric acid) and phytase by *Pseudomonas fluorescens*, thereby dissolving insoluble phosphorus (such as calcium phosphate and apatite); it releases mineral potassium and intensifies mineral decomposition by enhancing the adsorption and acidolysis capacity of *Bacillus mucilaginosus* on silicate minerals; and it promotes plant growth by promoting the secretion of plant hormones (such as IAA and gibberellin) and siderophores by *Azotobacter brasiliensis*. The advantages of electrochemically treated low-Hertz water for microbial communities are not only reflected in the performance improvement of individual strains, but also in the optimization of synergy among the microbial community: electrochemically treated low-Hertz water promotes the exchange of nutrients among different strains (e.g., nitrogen-fixing bacteria provide nitrogen sources, and phosphate-solubilizing bacteria provide phosphorus sources), improves overall fermentation efficiency, and achieves nutrient sharing and metabolic complementarity; it can neutralize acidic metabolites, optimize the fermentation environment, maintain the optimal growth pH of the microbial community, and reduce metabolic inhibition; it enhances stress resistance, strengthens cell membrane stability, and improves the survival rate of liquid microbial agents under stress conditions such as high temperature and high salt. Therefore, small molecular clusters have unique physicochemical advantages in microbial fermentation, and can significantly improve microbial metabolic efficiency and product synthesis capabilities.

[0039] This liquid compound microbial agent, through the scientific formulation of eight functional bacteria, achieves a synergistic effect of soil remediation and nutrient enhancement. Firstly, it addresses drought resistance, water retention, and soil structure improvement. *Bacillus megaterium* and *Streptomyces* secrete large amounts of extracellular polysaccharides and hydrophobic proteins, which, in conjunction with the biocollagen produced by *Bacillus mucilaginosus*, effectively bind soil particles, promote the formation of stable aggregates, significantly improve soil water-holding capacity, and alleviate water stress in drylands. *Azotrophus brasiliensis* secretes auxins (such as IAA) that strongly stimulate crop root development, forming a deep and extensive root network, enhancing water and nutrient absorption efficiency, and forming a closed loop of nitrogen nutrient supply with the nitrogen-fixing activity of *Azotrophus brownii*, thus improving crop drought resistance and tolerance to poor soil conditions. Secondly, it promotes the synergistic activation of nutrient elements. Azotobacter chrysogenum converts atmospheric nitrogen into ammonium nitrogen, providing a sustainable nitrogen source for the system; Pseudomonas fluorescens secretes organic acids to dissolve calcium phosphate fixed in calcareous soil, releasing soluble phosphorus; Bacillus mucilaginosus decomposes silicate minerals to release potassium, and further enhances phosphorus and potassium activation efficiency through synergistic effects with Pseudomonas fluorescens via organic acids, overcoming the problem of nutrient fixation in calcareous soils. Thirdly, there is a synergistic mechanism of microecological regulation and biocontrol. Bacillus subtilis produces lipopeptide antimicrobial substances (such as surfactants) to inhibit soil-borne pathogens, and the rhizosphere biofilm it forms provides colonization protection for functional microbial communities; Trichoderma echinosporum lyses the cell walls of pathogenic fungi through hyperparasitism, and its secreted chitinase can degrade organic pollutants, and its combined use with Bacillus subtilis enhances disease control efficiency; the Trichoderma hyphal network also expands colonization channels for other microbial communities, enhancing the soil migration capacity of the microbial community.

[0040] Regarding the stability of the microbial agent, it ensures functional durability through multiple strategies: extracellular polysaccharides secreted by *Bacillus mucilaginosus* and *Bacillus megaterium*, along with hydrophobic proteins produced by *Streptomyces*, combine with *Trichoderma echinococcosis* hyphae to form a biogel layer, effectively buffering drought, pH fluctuations, and heavy metal stress; antimicrobial peptides produced by *Bacillus subtilis* inhibit competition from indigenous bacteria, ensuring the colonization advantage of exogenous bacteria; and *Pseudomonas fluorescens* tolerates adverse stress through its oxidase system, consolidating the environmental adaptability of the microbial community. This self-protective system based on microbial community interactions enables the agent to achieve a survival rate and stability far exceeding that of conventional microbial agents in harsh environments.

[0041] Regarding the application rate of the microbial agent, its high efficiency stems from the synergistic effect and functional amplification of the microbial community: *Azotobacter brasiliensis* promotes root growth, expanding the colonization space of the microbial agent; *Bacillus mucilaginosus* extracellular polysaccharides enhance the adsorption capacity of the rhizosphere microbial community; *Trichoderma echinosporum* mycelial network carries nitrogen-fixing and phosphate-solubilizing spores deep into soil pores, improving space utilization; the biocolloidal structure formed by *Bacillus megaterium* and *Streptomyces* encapsulates the functional microbial community, constructing a slow-release microecological unit and extending the action time of the microbial agent. These multiple synergistic effects significantly improve the remediation efficiency per unit of microbial agent, resulting in a significantly lower application rate compared to conventional microbial agents, making it particularly suitable for low-cost ecological restoration of large areas of dry hillsides.

[0042] From the proportions of the liquid compound microbial agent, nitrogen-fixing bacteria (Azotobacter brownii) accounted for the largest proportion. As the core of nitrogen supply, its efficient nitrogen-fixing ability provides the basic nitrogen source for the entire microbial community. Growth-promoting bacteria (Azospirillum brasiliensis) have both nitrogen-fixing and indoleacetic acid (IAA) synthesis functions, accounting for 2 parts, which can enhance crop growth-promoting effects. Drought-resistant bacteria accounted for 2 parts in total, with Bacillus megaterium and Streptomyces working synergistically in a 1.2:0.8 ratio. The former secretes extracellular polysaccharides to improve soil water retention, while the latter produces hydrophobic proteins and... The compound contains stress-resistant metabolites, which together enhance the drought resistance of the microbial community and work with growth-promoting bacteria to retain water and promote root growth. Phosphate-solubilizing bacteria (Pseudomonas fluorescens) and potassium-solubilizing bacteria (Bacillus mucilaginosus) each comprise one part, meeting the soil's phosphorus and potassium activation requirements. Biocontrol bacteria (Bacillus subtilis) and synergistic bacteria (Trichoderma echinosporum) each comprise one part; Bacillus subtilis inhibits pathogens by secreting antimicrobial peptides, while Trichoderma echinosporum promotes the stability of the inoculant and the decomposition of organic matter. The ratio of these two is lower than that of bacteria to avoid interspecific competitive inhibition. This invention, through the compatibility and synergistic fermentation of multiple functional strains such as nitrogen fixation, drought resistance, phosphorus and potassium solubilization, growth promotion, biocontrol, and synergistic effects, forms a complete microbial ecosystem. It emphasizes a strategy of "prioritizing nitrogen fixation, promoting growth and drought resistance in parallel, ensuring phosphorus and potassium solubilization, and maintaining stability through biocontrol," perfectly addressing the pain points of nutrient-poor and drought-dominated dryland slopes. The high nitrogen fixation ratio highlights the nitrogen fixation effect, compensates for soil nitrogen deficiency, and drought-resistant and growth-promoting bacteria work together to solve the problem of water deficiency. Phosphate-solubilizing and potassium-solubilizing bacteria specifically activate calcium to fix nutrients. The low proportion of biocontrol bacteria and synergistic bacteria ensures that the functions are effective without disrupting the balance of the microbial community, forming a self-sustaining and highly resistant micro-ecological cycle system. In particular, the application of electrochemical low-hertz water throughout the process provides a stable guarantee for the improvement of the bacterial agent yield, which is significantly higher than that of single-strain culture. In addition, the subsequent industrial automated control of bacterial fertilizer production makes the bacterial fertilizer highly adaptable to dry hillsides and has stable efficacy.

[0043] In the preparation of the liquid compound bacterial agent, succinic acid and sodium molybdate are added to the system during the first sequential fermentation at the mid-logarithmic growth phase (12-16 hours). At this stage, the bacterial metabolic activity is highest, and the absorption efficiency of nutrients is also at its peak. Succinic acid, as an intermediate in the tricarboxylic acid cycle (TCA), directly provides energy and a carbon skeleton for the bacteria; sodium molybdate, as a core cofactor of nitrogenase, avoids metal toxicity at low concentrations and maintains consistency with the concentration in the basal culture medium of nitrogen-fixing bacteria, thus helping to maintain nitrogenase stability. Therefore, a pulsed addition method is used to avoid excessively high instantaneous concentrations that could inhibit bacterial growth.

[0044] After the first fermentation step is complete and the system pH stabilizes, the second fermentation step begins. At this stage, glycerol is added as a slow-release carbon source to induce phosphate-solubilizing bacteria to synthesize phosphatase. To prevent local concentrations exceeding 10 mM from inhibiting cell growth, glycerol is added continuously (0.5 g / L·h); calcium phosphate is added in three batches, utilizing its insoluble nature to continuously induce enzyme production by phosphate-solubilizing bacteria, avoiding precipitation and uneven dissolved oxygen distribution caused by a single high-concentration addition. Furthermore, glycerol and calcium phosphate have a synergistic effect: glycerol provides energy, and calcium phosphate serves as a substrate; simultaneous addition of both synergistically activates the phosphate-solubilizing metabolic pathway.

[0045] At the start of the third fermentation, add 200-mesh potassium feldspar powder (10 g / L) in two separate additions (6 hours apart) to avoid excessive addition leading to increased system viscosity and reduced dissolved oxygen efficiency. The oxalic acid secreted by *Trichoderma* can synergistically decompose the silicate structure in the potassium feldspar powder. Once the *Trichoderma echinosporum* seed culture is transferred to the fermenter, immediately start mechanical stirring (150-200 rpm) to increase the dissolved oxygen level to 40-50% (as *Trichoderma* is a strictly aerobic fungus), while simultaneously promoting sufficient contact between the potassium feldspar powder and the fungal cells, thus improving the fungal reproduction efficiency.

[0046] This invention provides a bio-fertilizer suitable for soil micro-ecological restoration in dry hillside areas. The raw materials are a liquid compound microbial agent and electrochemical low-Hertz water, with solid components including lignite powder, wheat bran, and soybean meal. While meeting the requirements of >40% organic matter, >200 million live bacteria / gram, and 50%-60% moisture content in the fermentation raw materials, the proportion of lignite powder is maximized to 85% by reducing wheat bran and soybean meal to the minimum necessary amount (ensuring microbial nutrition), significantly reducing raw material costs. It is prepared using a secondary fermentation process, incorporating micro-oxygenation technology to replace traditional turning during production, reducing production costs and energy consumption. Combined with an intelligent material distribution system, it achieves continuous production without human intervention, suitable for large-scale production lines. Furthermore, intermittent high-oxygen stimulation significantly improves the efficiency of solid-state fermentation and product quality. Because it is prepared using the above-mentioned liquid compound microbial agent suitable for dry slopes, this microbial agent has multiple functions such as nitrogen fixation, drought resistance, phosphorus solubilization, potassium solubilization, growth promotion, biocontrol, and synergistic effects. It can form a complete microbial ecosystem in the soil. Therefore, the microbial fertilizer provided by this invention is highly suitable for the problems of drought and water shortage, poor soil storage capacity, and soil calcification in dry slopes. It not only increases crop yield but also improves soil properties. Moreover, the preparation process of the soil microecological restoration bio-fertilizer for dry slopes provided by this invention is a comprehensive design for industrial production. Therefore, in actual crop planting applications, this microbial fertilizer has stable effects and requires a small amount. The application amount can be reduced by 70-98% compared with urea fertilizer for the same area, while increasing crop yield by 22.4-22.61%, increasing the available phosphorus content in the soil by 38.89%, the available nitrogen content by 25.0%, and the organic matter content by 13.68%, and reducing the incidence of diseases by 43.33-48.00%, thus achieving the synergistic goals of increased crop yield, improved quality, and healthy soil. This solves the problem of unstable efficacy and large fertilizer application rates in biological agents and fertilizers made from single strains or simple combinations of strains. Detailed Implementation

[0047] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading this description, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0048] Example 1: Preparation of a liquid compound microbial agent for soil microecological remediation suitable for arid land

[0049] The liquid compound bacterial agent for soil microecological remediation suitable for arid land described in this embodiment includes eight functional bacterial strains: drought-resistant bacteria, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, potassium-solubilizing bacteria, growth-promoting bacteria, biocontrol bacteria, and synergistic bacteria. The drought-resistant bacteria are *Bacillus megaterium* de Bar and *Streptomyces* sp.; the nitrogen-fixing bacteria are *Azotobacter chroococcum*; the phosphate-solubilizing bacteria are *Pseudomonas fluorescens*; the potassium-solubilizing bacteria are *Paenibacillus mucilaginosus*; the growth-promoting bacteria are *Azospirillum brasilense*; the biocontrol bacteria are *Bacillus subtilis*; and the synergistic bacteria are *Trichoderma asperellum*. The total effective bacterial count is ≥2 × 10⁻⁶. 10 CFU / mL), fungal spore count ≥1×10 8 Spores / mL; The eight functional strains of *Bacillus megaterium*, *Streptomyces*, *Azotobacter chrysogenum*, *Pseudomonas fluorescens*, *Bacillus mucilaginosus*, *Azotobacter brasiliensis*, and *Bacillus subtilis* were prepared by liquid fermentation using electrochemically low-Hertz water. The liquid fermentation specifically includes the following stages:

[0050] Eight bacterial strains were inoculated from preservation slant agar to specialized slant culture media: nitrogen-fixing bacteria on Assoube medium, phosphate-solubilizing bacteria on KB medium, drought-resistant and biocontrol bacteria on LB medium, potassium-solubilizing bacteria on potassium-solubilizing medium, and *Trichoderma echinosporum* on PDA medium. All five media were prepared using electrolytically low-Hertz water. The cultures were incubated at 30°C for 24-48 hours until the logarithmic growth phase (OD50). 600 When the concentration was ≥1.0, the samples were transferred to shake flasks for culture, and then transferred to seven primary seed tanks for culture.

[0051] When the bacterial count is ≥5×10 8 At a CFU / mL concentration, premixed seed solutions of *Azotobacter chamaescoparia*, *Azotobacter brasiliensis*, and *Bacillus megaterium* were mixed at a volume ratio of 1:1:0.5 to obtain premixed seed solution 1. Premixed seed solutions of *Pseudomonas fluorescens*, *Bacillus subtilis*, and *Streptomyces* were mixed at a volume ratio of 1:1:0.3 to obtain premixed seed solution 2. After incubation at 30°C for 30 minutes, both premixed solutions can be used for sequential fermentation. When the *Bacillus subtilis* bacterial count is ≥5×10⁻⁶, the premixed solutions are suitable for sequential fermentation. 8 At CFU / mL, the number of Trichoderma acicularis spores is ≥1×10⁻⁶. 7 When the spore count is 1 mL, it can be used for sequential fermentation.

[0052] The inoculation amounts of the premixed seed liquid 1, premixed seed liquid 2, Bacillus mucilaginosus seed liquid, and Trichoderma echinosporum seed liquid are 9.8%-10.2%, 4.8%-5.2%, 4.8%-5.2%, and 2.8%-3.2% of the fermentation volume, respectively. The inoculation amount of electrochemical low-Hertz water is 76.4%-77.6% of the fermentation volume. The electrochemical low-Hertz water has a molecular cluster of ≤6 molecules and a pH of 7.0–7.5.

[0053] The subsequent three-stage sequential culture was carried out in the main fermenter:

[0054] S1: Propagate nitrogen-fixing bacteria, growth-promoting bacteria, and drought-resistant bacteria to establish a nitrogen source foundation: Add electrolytic low-Hertz water to the sterilized main fermenter, and add pre-mixed seed solutions of *Azotobacter spp.*, *Azotobacter brasiliensis*, and *Bacillus megaterium* (premixed seed solution 1), with an inoculation volume of 9.8%-10.2% of the fermentation volume; adjust to the first-order fermentation conditions: pH 7.0, dissolved oxygen 25-35%, temperature 30℃, humidity at the top of the fermenter 92%±1%, fermentation for 22-24 hours; when fermentation reaches the middle of the logarithmic growth phase, add the growth factors succinic acid and sodium molybdate. Succinic acid and sodium molybdate are added simultaneously using a pulsed slow-flow injection method, with the concentration of succinic acid being 0.01% and the concentration of sodium molybdate being 10μM. Each addition is 1 / 3 of the total required amount, with an interval of 2 hours, for a total of 3 times.

[0055] S2: Introduction of phosphate-solubilizing bacteria and biocontrol bacteria: After the S1 stage, adjust to the second-sequence fermentation conditions, and add pre-mixed seed culture of *Pseudomonas fluorescens* and *Bacillus subtilis* (premixed seed culture 2) to the main fermenter at an inoculation rate of 4.8%-5.2% of the fermentation volume. The second-sequence fermentation conditions are: pH 6.5, dissolved oxygen 35-45%, temperature 32℃, humidity at the top of the fermenter 92%±1%, and fermentation time 16-18 hours. After fermentation is complete and the pH of the system is stable, add the growth factors glycerol and calcium phosphate. Glycerol is added continuously at a concentration of 5 mM and a flow rate of 0.5 g / L·h to avoid local concentrations exceeding 10 mM. The calcium phosphate is added at a concentration of 2 g / L in three batches, each batch containing 1 / 3 of the total required amount, with an interval of 4 hours between each batch.

[0056] S3: Initiating the synergistic metabolism of potassium-solubilizing bacteria and Trichoderma to activate mineral decomposition: After the S2 stage fermentation is completed, Bacillus mucilaginosus seed liquid is added to the main fermenter at an inoculation amount of 4.8%-5.2% of the fermentation volume. Then, potassium feldspar powder and chitin powder are added simultaneously in two batches, with an interval of 6 hours between each addition. The potassium feldspar powder has a particle size of 200 mesh and a concentration of 10 g / L. The chitin powder is first dissolved in small molecule cluster water and then added at a concentration of 0.5 g / L. After 12 hours of fermentation, Trichoderma echinococcus seed liquid is added at an inoculation amount of 2.8%-3.2% of the fermentation volume. Mechanical stirring is started and the fermentation conditions are adjusted to the third time sequence: pH 5.5, dissolved oxygen 45-55%, temperature 28℃, humidity of the top space of the fermenter 88%±1%, and fermentation time is 34-36 hours. After the fermentation is completed and the pH of the system is stable, glycerol and calcium phosphate are added. Potassium feldspar powder with a particle size of 200 mesh and a concentration of 10 g / L was added twice, with a 6-hour interval between additions. When the viable cell count in the main fermenter is ≥2×10⁻⁶... 10 Fermentation was completed when the concentration of CFU / mL was reached, yielding the liquid compound microbial agent suitable for soil microecological restoration in arid lands.

[0057] In some embodiments of the present invention, the fermentation equipment used in the above fermentation process includes:

[0058] The main fermentation tank includes a three-layer inclined blade agitator, jacketed heating / cooling, three humidity sensors, a saturated humidifier, a refrigerated dehumidifier, a hot air circulation device, a condensate return and discharge system, an automated control system, and a functional detection module.

[0059] In some embodiments of the present invention, the main fermentation tank has a volume of 3000L, and the humidity sensors are respectively placed on the top / middle / bottom of the tank, spaced 15cm apart; the saturated humidifier has an adjustable water temperature of 30-32℃ and a processing capacity of 6m³. 3 / h; the refrigerated dehumidifier can cool down to 15℃, and the humidity after dehumidification is ≤80%; the hot air circulation device has an air temperature of 30℃±1℃ and an air speed of 0.5-1.2m / s, which can be adjusted as needed; the condensate return and discharge system is equipped with a 0.22μm sterile filter membrane; the automatic control system includes PLC linkage functions for humidity, temperature, dissolved oxygen, and stirring speed, with a response time of <10s, and can preset parameter curves for dryland farming; the functional detection module monitors the effective phosphorus / potassium concentration online and detects viable bacteria count, proline, ferrophilic acid, and nitrogenase activity offline.

[0060] In some embodiments of the present invention, the humidity of the space above the fermentation tank is regulated by the humidity sensor, the saturated humidifier, and the refrigerated dehumidifier.

[0061] Example 2: Preparation of a soil microecological restoration bio-fertilizer suitable for dry hillsides

[0062] The bio-fertilizer described in this embodiment is prepared using the liquid compound microbial agent for soil microecological restoration suitable for dry hillsides described in Example 1.

[0063] In a specific embodiment of the present invention, the raw materials of the bio-fertilizer include: liquid compound microbial agent, electrochemical low-hertz water, and solid components: lignite powder, wheat bran, and soybean meal; the total amount of the solid components is 100%, and the proportions of the three components are: lignite powder 70-85%, wheat bran 8-15%, and soybean meal 8-20%; the particle size of the lignite powder is 80-100 mesh, and the initial moisture content is 10-15%; the initial moisture content of the wheat bran and soybean meal is 8-12% each. After the above solid components are mixed evenly, electrochemical low-hertz water is added and stirred thoroughly. At the same time, the liquid compound microbial agent is added simultaneously during the stirring process, and the amount added is calculated as 0.8-10% of the total amount of solid components, so that the total moisture content of the material reaches 50-60%.

[0064] The method for preparing the bio-fertilizer includes:

[0065] A1: The above-mentioned liquid compound microbial agent, electrochemical low-hertz water, and solid components: lignite powder, wheat bran, and soybean meal are added to the intelligent mixing and stirring system. After being mixed evenly, the mixture is conveyed to the intelligent solid-state fermentation system production line through the independently invented intelligent material distribution system (patent authorization announcement number CN116553963B) for the first solid-state fermentation. The intelligent fermentation system regulates the temperature during the fermentation process through temperature sensors and linkage with intermittent micro-burst oxygen frequency: the initial stage temperature is 42-45℃, maintained for 22-24 hours; the peak stage temperature is 60-65℃, maintained for 46-48 hours; and the final stage temperature is 40-45℃, maintained for 22-24 hours. When the temperature remains constant for 24 consecutive hours, the material moisture content is ≤40%, the material color is dark brown, there is no odor, and the material is loose to the touch without sticking, the fermentation of stage A1 ends.

[0066] A2: The material obtained from the first fermentation in A1 is rearranged into the aging and fermentation production line through an intelligent material distribution system for the second fermentation: The material is naturally piled up, and combined with intelligent monitoring, the residual heat and residual microorganisms of the material are used to complete the deep decomposition, which lasts for 10-12 days. When the material naturally cools down to a moisture content of 15-29%, the color is uniformly dark brown, the texture is loose, and it has an earthy smell without other odors, the pH is stable at 6.5-7.5, and the number of beneficial live bacteria is ≥200 million / g, the second fermentation is completed, and the soil micro-ecological restoration bio-fertilizer suitable for dry hillsides is obtained.

[0067] Experiment Example 1: Effect of Electrochemical Low-Hertz Water on the Number of Viable Cells at Different Stages of Fermentation

[0068] Experimental group: Liquid compound bacterial agent prepared according to the method in Example 1.

[0069] Control group: The electrochemical low-Hertz water in Example 1 was replaced with sterilized water, and all other operations were the same as in Example 1. The number of viable bacteria in each fermentation stage of the experimental and control groups was measured. Statistical method: Data were analyzed using ANOVA (α=0.05), with ≥3 replicates per group. The results are shown in Table 1. At the end of the first time series, the number of viable bacteria in the experimental group increased by 50% compared to the control group; at the end of the second time series, the number of viable bacteria in the experimental group increased by 46.2% compared to the control group; and at the end of the third time series, the number of viable bacteria in the experimental group increased by 38.9% compared to the control group. This indicates that electrochemical low-Hertz water can effectively improve fermentation efficiency.

[0070] Table 1. Viable bacterial count

[0071]

[0072] Experiment Example 2: The effect of using bio-fertilizer for soil micro-ecological restoration in dry hillside areas.

[0073] 2.1 Maize Experiment

[0074] (1) Test location:

[0075] Yu County, Zhangjiakou City, Hebei Province, has a temperate continental monsoon climate with an average annual precipitation of 420 mm. The soil is chestnut calcareous soil with an organic matter content of 1.2%, a pH of 7.8, and a topsoil thickness of 30 cm.

[0076] (2) Test fertilizers and fertilization methods:

[0077] Processing Group 1:

[0078] Fertilizer: Bio-fertilizer 1 was obtained according to the preparation method of Example 2, with the amount of liquid compound microbial agent added being 0.8%.

[0079] Application method: Use Stanley commercial organic fertilizer as base fertilizer at a rate of 600 kg / mu. Before planting, mix the seeds with bio-fertilizer 1 at a rate of 0.9 kg / mu. Spray from the jointing stage to the large trumpet stage (dissolve bio-fertilizer 1 in water and spray the supernatant) at a rate of 10 kg / mu.

[0080] Processing Group 2:

[0081] Fertilizer: Replace the small molecule cluster water in the preparation method of Example 2 with ordinary sterilized water, and perform the other operations exactly the same as in Example 2 to obtain bio-fertilizer 2;

[0082] Application method: Same as treatment group 1.

[0083] Control group 1:

[0084] Fertilizer: The liquid compound bacterial agent in the preparation method of Example 2 was replaced with a single brown azotocin agent, and the other operations were exactly the same as in Example 2, to obtain a single nitrogen-fixing fertilizer.

[0085] Application method: Same as treatment group 1.

[0086] Control group 2:

[0087] Fertilizers: Sinochem Compound Fertilizer (22-18-10), Sinochem Urea (nitrogen content ≥46%), Stanley Commercial Organic Fertilizer (organic matter ≥30%)

[0088] Application method: Apply Sinochem compound fertilizer (22-18-10) (30kg / mu) and Stanley commercial organic fertilizer (600kg / mu) as base fertilizer, and apply Sinochem urea (nitrogen content ≥46%) (20kg / mu) as top dressing from the jointing stage to the large trumpet mouth stage.

[0089] (3) Experimental design:

[0090] A randomized block design was adopted, with each group having a planting area of ​​1 mu (approximately 0.16 acres) and 3 replicates. The variety planted was "Zhangdan 25", and the field management of each group was consistent.

[0091] (4) Experimental results:

[0092] The experimental results are shown in Table 2 below: Compared with treatment group 2 and control group 1, treatment group 1 showed increased plant height, leaf area index, number of aerial roots, stem diameter, yield per unit area, and available phosphorus content in the soil. It also showed a shorter tasseling and silking time and a lower incidence of stem rot. This indicates that bio-fertilizer 1, the bio-fertilizer provided by this invention suitable for dry slopes, is significantly more effective than bio-fertilizer 2 in treatment group 2 and nitrogen-fixing fertilizer in control group 1 under the same application method and dosage. It can effectively promote corn growth, increase yield, and reduce the incidence of corn stem rot. Compared with control group 2, treatment group 1 showed increased plant height, leaf area index, number of aerial roots, stem diameter, yield per unit area, and available phosphorus content in the soil. It also showed a shorter tasseling and silking time and a lower incidence of stem rot. This indicates that the dosage of bio-fertilizer 1, the bio-fertilizer provided by this invention suitable for dry slopes, is much lower than that of ordinary commercial fertilizers and organic fertilizers. It has high applicability to dry slopes and its growth-promoting and soil-remediating effects are significantly better than ordinary commercial fertilizers and organic fertilizers.

[0093] Table 2 Results of the maize planting experiment

[0094]

[0095] 2.2 Millet Experiment

[0096] (1) Test location:

[0097] Lingqiu County, Datong City, Shanxi Province, has a temperate semi-arid climate with an average annual precipitation of 380 mm. The soil is loess soil with an organic matter content of 0.9%, a pH of 8.0, and a topsoil thickness of 25 cm.

[0098] (2) Test fertilizers and fertilization methods:

[0099] Processing Group 1:

[0100] Fertilizer: The bio-fertilizer 1 prepared according to the preparation method of Example 2 has a liquid compound microbial agent added at a rate of 10%.

[0101] Application method: Use Shangguyuanwo commercial organic fertilizer (organic matter ≥35%) as base fertilizer at a rate of 150 kg / mu; before sowing, use bio-fertilizer 1 to mix the seeds at a rate of 0.5 kg / mu; spray at the jointing stage (dissolve bio-fertilizer 1 in water and spray the supernatant) at a rate of 6 kg / mu; spray at the booting stage at a rate of 10 kg / mu.

[0102] Processing Group 2:

[0103] Fertilizer: Replace the small molecule cluster water in the preparation method of Example 2 with ordinary sterilized water, and perform the other operations exactly the same as in Example 2 to obtain biological microbial fertilizer 2;

[0104] Application method: Same as treatment group 1.

[0105] Control group 1:

[0106] Fertilizer: The liquid compound bacterial agent in the preparation method of Example 2 was replaced with a single brown azotocin agent, and the other operations were exactly the same as in Example 2, to obtain a single nitrogen-fixing fertilizer.

[0107] Application method: Same as treatment group 1.

[0108] Control group 2:

[0109] Fertilizers: Sinochem Compound Fertilizer (22-18-10), Weixian Shennong Commercial Organic Fertilizer, Sinochem Urea

[0110] Application method: Use Sinochem compound fertilizer (22-18-10) (40kg / mu) and Weixian Shennong commercial organic fertilizer (150kg / mu) as base fertilizer; apply Sinochem urea at the jointing stage and apply Sinochem urea at the booting stage.

[0111] (3) Experimental design:

[0112] A randomized block design was adopted, with each group having a planting area of ​​1.5 mu (approximately 0.16 acres) and three replicates. The variety planted was "Jingu 21", and the field management of each group was consistent.

[0113] (4) Test results

[0114] The experimental results are shown in Table 3 below: Compared with treatment group 2 and control group 1, treatment group 1 showed increased plant height, ear length, thousand-grain weight, yield per unit area, and soil organic matter, decreased powdery mildew incidence, and improved drought resistance coefficient. This indicates that bio-fertilizer 1, i.e., the bio-fertilizer provided by this invention suitable for hillside drylands, is significantly more effective than bio-fertilizer 2 in treatment group 2 and nitrogen-fixing fertilizer in control group 1 under the same application method and dosage. It can effectively promote millet growth, reduce disease incidence, increase soil organic matter, and improve soil drought resistance coefficient. Compared with control group 2, treatment group 1 showed increased plant height, ear length, thousand-grain weight, yield per unit area, and soil organic matter, decreased powdery mildew incidence, and improved drought resistance coefficient. This indicates that the dosage of bio-fertilizer 1, i.e., the bio-fertilizer provided by this invention suitable for hillside drylands, is much lower than that of ordinary commercial fertilizers and organic fertilizers. Its effects on promoting growth, resisting disease, improving soil, and adaptability to hillside drylands are significantly better than those of ordinary commercial fertilizers and organic fertilizers.

[0115] Table 3 Results of the Millet Experiment

[0116]

[0117] 2.3 Panax notoginseng experiment

[0118] (1) Experimental location: Wenshan, Yunnan Province, with a subtropical monsoon climate, an average annual precipitation of 1200 mm, red soil with an organic matter content of 1.5% and a pH of 6.5, and greenhouse cultivation (70% shading rate).

[0119] (2) Test fertilizers and fertilization methods:

[0120] Processing Group 1:

[0121] Fertilizer: The bio-fertilizer 1 prepared according to the preparation method of Example 2 has a liquid compound microbial agent addition amount of 6%.

[0122] Application method: Use Wenshan Zhengbang commercial organic fertilizer (organic matter ≥35%) (1500 kg / mu) as base fertilizer; apply bio-fertilizer 1 (10 kg / mu) in furrows at the time of transplanting; spray bio-fertilizer 1 (12 kg / mu) during the seedling stage, bud stage and tuber enlargement stage.

[0123] Processing Group 2:

[0124] Fertilizer: Replace the small molecule cluster water in the preparation method of Example 2 with ordinary sterilized water, and perform the other operations exactly the same as in Example 2 to obtain biological microbial fertilizer 2;

[0125] Application method: Same as treatment group 1.

[0126] Control group 1:

[0127] Fertilizer: The liquid compound bacterial agent in the preparation method of Example 2 was replaced with a single brown azotocin agent, and the other operations were exactly the same as in Example 2, to obtain a single nitrogen-fixing fertilizer.

[0128] Application method: Same as treatment group 1.

[0129] Control group 2:

[0130] Fertilizers: Sinochem Compound Fertilizer (10-20-20), Wenshan Zhengbang Commercial Organic Fertilizer, Stanley Compound Fertilizer (15-5-10), Stanley Compound Fertilizer (15-15-15), Stanley Compound Fertilizer (10-10-20).

[0131] Application method: Use Sinochem compound fertilizer (10-20-20) (80kg / mu) and Wenshan Zhengbang commercial organic fertilizer (1500kg / mu) as base fertilizer; apply Stanley compound fertilizer (15-5-10) 5kg / mu during the seedling stage; apply Stanley compound fertilizer (15-15-15) 25kg / mu during the bud stage; apply Stanley compound fertilizer (10-10-20) 30kg / mu during the tuber enlargement stage.

[0132] (3) Experimental design:

[0133] Greenhouse cultivation (70% shading rate), randomized block design: 1.5 mu per group, 3 replicates, with consistent field management. The variety planted was "Wen Sanqi".

[0134] (4) Test results

[0135] The experimental results are shown in Table 4. Compared with treatment group 2 and control group 1, treatment group 1 showed increased plant height, fresh weight of tubers, total saponin content, available nitrogen in the soil, and number of tubers per plant, while the incidence of root rot decreased. This indicates that bio-fertilizer 1, which is the bio-fertilizer for arid land provided by this invention, is significantly more effective than bio-fertilizer 2 in treatment group 2 and nitrogen-fixing fertilizer in control group 1 under the same application method and dosage. It can effectively improve the yield, quality, and available nitrogen content of Panax notoginseng, and reduce the incidence of root rot. Compared with control group 2, treatment group 1 showed increased plant height, fresh weight of tubers, total saponin content, available nitrogen in the soil, and number of tubers per plant, while the incidence of root rot decreased. This indicates that the dosage of bio-fertilizer 1, which is the bio-fertilizer for arid hillsides provided by this invention, is much lower than that of ordinary commercial fertilizers and organic fertilizers, and its effects on promoting growth, improving quality, and restoring soil are significantly better than those of ordinary commercial fertilizers and organic fertilizers.

[0136] Table 4 Results of Panax notoginseng planting trials

[0137]

[0138] 3. Summary

[0139] 3.1 Comparison of the effects of bio-fertilizers produced based on liquid compound microbial agents and single nitrogen-fixing microbial agents

[0140] This invention uses a combination of eight functional bacterial strains—Bacillus megaterium (drought-resistant), Azotobacter chrysogenum (nitrogen fixation), Pseudomonas fluorescens (phosphate solubilization), Bacillus mucilaginosus (potassium solubilization), Azotobacter brasiliensis (growth promotion), Bacillus subtilis (biocontrol), and Trichoderma echinosporum (antagonism)—to prepare a liquid composite bacterial agent (treatment group 1). Through the synergistic effect of "drought resistance-nitrogen fixation-phosphate solubilization-potassium solubilization-growth promotion-biocontrol," the growth promotion effect is significantly better than that of a single nitrogen-fixing bacterial agent (control group 1).

[0141] In the maize experiment: compared with the control group 1, the yield per unit area increased by 18.02%, the available phosphorus in the soil increased by 40%, and the incidence of stalk rot decreased by 54.8% (Table 2).

[0142] In the millet experiment: compared with the control group 1, the yield per unit area of ​​treatment group 1 increased by 21.58%, and the disease index of sheath blight decreased by 50% (Table 3).

[0143] In the Panax notoginseng experiment: compared with the control group 1, the number of fruits per plant increased by 44.44%, the number of Fusarium oxysporum in the soil decreased by 90%, and the vitamin C content of the fruit increased by 24.69% (Table 4).

[0144] 3.2 Comparison of the effects of electrochemical low-hertz water and ordinary sterilized water

[0145] This invention uses electrochemical low-hertz water with a half-width at half-maximum (WHM) of ≤100Hz to prepare bio-fertilizer 1 (treatment group 1). By improving the permeability of microbial cell membranes and enhancing the adhesion and diffusion of bacterial agents, it is significantly superior to bio-fertilizer 2 (treatment group 2) made with ordinary water.

[0146] In the maize experiment, compared with treatment group 2, treatment group 1 showed a 6.46% increase in plant height and a 7.03% increase in yield per unit area (Table 2). Mechanism of action analysis: Electrochemical low-Hertz water improved the proliferation efficiency of live bacteria in the inoculant, enhancing nutrient absorption by maize roots. In the millet experiment, compared with treatment group 2, treatment group 1 showed a 5.56% increase in thousand-grain weight and a 10.94% increase in yield per unit area (Table 3). In the Panax notoginseng experiment, compared with treatment group 2, treatment group 1 showed a 12.0% increase in fresh tuber weight and an 8.97% increase in total saponin content (Table 4).

[0147] 3.3 Comparison of Bio-fertilizer with Conventional Organic Fertilizer and Chemical Fertilizer

[0148] The solid bio-fertilizer 1 (treatment group 1) of the present invention has significant advantages over conventional commercial organic fertilizer (control group 2) in terms of increasing yield, reducing disease, improving quality and improving soil.

[0149] In the maize experiment, compared with control group 2, treatment group 1 showed a 17.65% increase in plant height and a 31.0% increase in yield per unit area (Table 2). Mechanism of action analysis: Electrochemical low-Hertz water improved the proliferation efficiency of viable bacteria in the inoculant, enhancing nutrient absorption by maize roots. In the millet experiment, compared with control group 2, treatment group 1 showed a 22.58% increase in thousand-grain weight and a 36.02% increase in yield per unit area (Table 3). In the Panax notoginseng experiment, compared with control group 2, treatment group 1 showed a 40.0% increase in fresh tuber weight and a 30.77% increase in total saponin content (Table 4).

[0150] 3.4 Summary

[0151] This invention quantifies and verifies the technical effects of increased yield, improved quality, reduced disease, and improved soil through planting trials on three crops: Treatment group 1, specifically the bio-fertilizer 1 provided by this invention suitable for dry hillsides, showed significant growth-promoting effects in growth-promoting trials on corn, millet, and Panax notoginseng, not only increasing yield and quality but also significantly improving soil (Table 5). This indicates that the bio-fertilizer is suitable for the characteristics of dry hillsides, has stable effects, requires low dosage, and can promote crop growth and improve soil properties.

[0152] Table 5. Comparison of effects between treatment group 1 and control group 2

[0153]

[0154] In summary, the soil microecological restoration bio-fertilizer for dry mountain slopes provided by this invention achieves increased yield and quality of corn, millet, and Panax notoginseng in dry mountain slopes through the complementary functions of eight strains of bacteria and rhizosphere ecological regulation, combined with electrochemical low-Hertz water enhancement and solid-state fermentation technology, and also plays a role in improving the soil.

Claims

1. A liquid compound microbial agent for soil microecological restoration suitable for dry slopes, characterized in that, The following eight functional strains were prepared using electrochemically low-Hertz water (i.e., small molecule cluster water) through a three-stage sequential inoculation and fermentation process: nitrogen-fixing bacteria: Azotobacter chroococcum; phosphate-solubilizing bacteria: Pseudomonas fluorescens; potassium-solubilizing bacteria: Paenibacillus mucilaginosus; growth-promoting bacteria: Azospirillum brasilense; biocontrol bacteria: Bacillus subtilis; synergistic bacteria: Trichoderma asperellum; and drought-resistant bacteria: Bacillus megaterium and Streptomyces sp. S1: Propagation of nitrogen-fixing bacteria, growth-promoting bacteria and drought-resistant bacteria: Add electrolytic low-hertz water to the sterilized main fermenter, and add pre-mixed seed liquid of *Azotobacter spp.*, *Azotobacter brasiliensis*, and *Bacillus megaterium*. Adjust the fermentation conditions to the first-order fermentation conditions: pH=7.0, dissolved oxygen 25-35%, temperature 30℃, humidity of the top space of the fermenter 92%±1%, fermentation time 22-24 hours; S2: Introduce phosphate-solubilizing bacteria, biocontrol bacteria, and drought-resistant bacteria to relieve phosphorus limitation: After the S1 stage, adjust to the second sequential fermentation conditions, and add pre-mixed seed liquid of Pseudomonas fluorescens, Bacillus subtilis, and Streptomyces to the main fermenter. The second sequential fermentation conditions are: pH=6.5, dissolved oxygen 35-45%, temperature 30℃, humidity of the top space of the fermenter 92%±1%, and fermentation time 16-18 hours. S3: Initiate the synergistic metabolism of potassium-solubilizing bacteria and Trichoderma to activate mineral decomposition: After the fermentation of the S2 stage, add Bacillus mucilaginosus seed liquid to the main fermenter. After fermentation for 12 hours, add Trichoderma echinococcosis seed liquid, turn on mechanical stirring and adjust to the third-sequence fermentation conditions: pH=5.5, dissolved oxygen 45-55%, temperature 28℃, humidity of the top space of the fermenter 88%±1%, fermentation for 34-36 hours; When the number of viable bacteria in the main fermenter is ≥2×10 10 Fermentation ends when CFU / mL is reached.

2. The liquid compound microbial agent for soil microecological restoration suitable for dry slopes according to claim 1, characterized in that, The ratio of nitrogen-fixing bacteria: phosphate-solubilizing bacteria: potassium-solubilizing bacteria: growth-promoting bacteria: biocontrol bacteria: synergistic bacteria: drought-resistant bacteria is 3:1:1:2:1:1:2, wherein the internal ratio of drought-resistant bacteria is Bacillus megaterium: Streptomyces = 1.2:0.

8.

3. The liquid compound microbial agent for soil microecological restoration suitable for dry slopes according to claim 2, characterized in that, The seed culture preparation method is as follows: seven types of functional strains are inoculated from the preservation slant into a special slant culture medium and cultured at 30℃ for 24-48 hours until the logarithmic phase, i.e., OD. 600 When the value is ≥1.0, the samples were transferred to shake flasks for culture, and then transferred to seven primary seed tanks for independent culture. The method for preparing the pre-mixed seed solution is as follows: when the bacterial count in the primary seed tank is ≥5×10⁻⁶... 8 When CFU / mL, the seed cultures of *Azotobacter chrysogenum*, *Azotobacter brasiliensis*, and *Bacillus megaterium* were mixed at a volume ratio of 1:1:0.5 to obtain premixed seed culture 1. The seed cultures of *Pseudomonas fluorescens*, *Bacillus subtilis*, and *Streptomyces* were mixed at a volume ratio of 1:1:0.3 to obtain premixed seed culture 2. After incubation at 30°C for 30 minutes, the two premixed seed cultures were used for sequential fermentation. When the number of Bacillus subtilis bacteria in the primary seed tank is ≥5×10 8 At CFU / mL, the number of Trichoderma acicularis spores is ≥1×10⁻⁶. 7 At a concentration of spores / mL, it can be used for sequential fermentation; The nitrogen-fixing bacteria and growth-promoting bacteria are prepared using Assoube medium, the phosphate-solubilizing bacteria are prepared using KB medium, the biocontrol bacteria and drought-resistant bacteria are prepared using LB medium, the potassium-solubilizing bacteria are prepared using potassium-solubilizing medium, and Trichoderma acicularis is prepared using PDA medium; all five media are prepared using electrochemical low-hertz water. The inoculation amounts of the premixed seed liquid 1, premixed seed liquid 2, Bacillus mucilaginosus seed liquid, and Trichoderma echinosporum seed liquid are 9.8%-10.2%, 4.8%-5.2%, 4.8%-5.2%, and 2.8%-3.2% of the fermentation volume, respectively. The inoculation amount of electrochemical low-hertz water is 76.4%-77.6% of the fermentation volume. The electrochemical low-hertz water has a molecular cluster of ≤6 molecules and a pH of 7.0–7.

5.

4. The liquid compound microbial agent for soil microecological restoration suitable for dry slopes according to claim 3, characterized in that, During the S1 stage, when fermentation reaches the middle of the logarithmic growth phase, add the growth factors succinic acid and sodium molybdate; after the S2 stage fermentation is completed and the system pH stabilizes at 6.6-7.0, add the growth factors glycerol and calcium phosphate; when the S3 stage is started, add the growth factors potassium feldspar powder and chitin powder.

5. The liquid compound microbial agent for soil microecological restoration suitable for dry slopes according to claim 4, characterized in that, S1 succinic acid and sodium molybdate are added simultaneously and in batches using a pulsed slow-flow injection method. The concentration of succinic acid is 0.01% and the concentration of sodium molybdate is 10 μM. The addition is done in three batches, with each batch containing 1 / 3 of the total required amount, and the interval between batches is 2 hours. The glycerol concentration in S2 is 5 mM, and it is added continuously at a flow rate of 0.5 g / L·h to avoid local concentrations exceeding 10 mM; the calcium phosphate concentration is 2 g / L, added in 3 portions, each portion being 1 / 3 of the total required amount, with an interval of 4 hours. The potassium feldspar powder in S3 is added in two batches. The potassium feldspar powder has a particle size of 200 mesh and a concentration of 10 g / L. The two additions are 6 hours apart.

6. A soil microecological restoration bio-fertilizer suitable for dry hillsides, characterized in that, It is prepared using the liquid compound microbial agent for soil microecological restoration suitable for dry hillsides as described in any one of claims 1-5.

7. The soil microecological restoration bio-fertilizer suitable for dry slopes according to claim 6, characterized in that, Preparation methods include: A1: The liquid compound microbial agent, electrochemical low-hertz water, and solid components (lignite powder, wheat bran, and soybean meal) described in claim 1 are added to a mixing system. After the mixture is evenly mixed, it is conveyed to the solid-state fermentation system production line through an intelligent material distribution system for the first solid-state fermentation. The solid-state fermentation system automatically adjusts the temperature during the fermentation process through a temperature sensor linked to the intermittent micro-burst oxygen frequency: the initial stage temperature is 42-45℃, maintained for 22-24 hours; the peak stage temperature is 60-65℃, maintained for 46-48 hours; and the final stage temperature is 40-45℃, maintained for 22-24 hours. A2: The material obtained from the first solid-state fermentation in A1 is rearranged into the aging and fermentation production line through an intelligent material distribution system for a second aging and fermentation: the naturally piled material is deeply decomposed using the residual heat and residual microorganisms. After 10-12 days, the fermentation ends, and the soil micro-ecological restoration bio-fertilizer suitable for dry hillsides is obtained.

8. The soil microecological restoration bio-fertilizer suitable for dry slopes according to claim 7, characterized in that, In component A1, the total amount of solid components—lignite powder, wheat bran, and soybean meal—is 100%, with the following proportions: lignite powder 70-85%, wheat bran 8-15%, and soybean meal 8-20%. The lignite powder has a particle size of 80-100 mesh and an initial moisture content of 10-15%. The initial moisture content of the wheat bran and soybean meal is 8-12%. After the solid components are mixed evenly, electrolytic low-hertz water is added and stirred thoroughly. Simultaneously, a liquid compound microbial agent is added during the stirring process, at a rate of 0.8-10% of the total solid components, so that the total moisture content of the material reaches 50-60%.

9. The soil microecological restoration bio-fertilizer suitable for dry slopes according to claim 8, characterized in that, The completion of the first fermentation stage A1 is indicated by the following: the temperature is maintained at the final stage temperature for 24 consecutive hours, the material moisture content is ≤40%, the material color is dark brown, there is no odor, it is loose when squeezed, and there is no stickiness.

10. The soil microecological restoration bio-fertilizer suitable for dry slopes according to claim 9, characterized in that, The completion of the second fermentation stage A2 is indicated by the following: when the material naturally cools to a moisture content of 15-29%, the color is uniformly dark brown, the texture is loose, it has an earthy smell without other off-odors, the pH is 6.5-7.5, and the number of beneficial live bacteria is ≥2×10⁻⁶. 10 When the concentration reaches / g, the second fermentation ends.

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