A native bacteria activation-soil improvement integrated soil regeneration granule, its preparation method and application

Abstract

This invention discloses an integrated soil regeneration granule for indigenous bacteria activation and soil improvement, and its preparation method. The granule employs a two-component (A / B) layered structure, consisting of a disintegration trigger core, an A-component habitat layer, and a B-component functional layer from the inside out. The disintegration trigger core contains citric acid microcapsules coated with gelatin-gum arabic, which, in synergy with sodium bicarbonate, achieves precise gas production and disintegration over 12 months, propelling microbial communities and nutrients to deeper soil layers. The A-component habitat layer constructs a gradient porous structure, inhibiting pore blockage and efficiently capturing indigenous bacteria. The B-component functional layer relies on biochar and humic acid for nutrient supply, and incorporates oyster shell powder to construct a pH buffering system. This granule can both capture and colonize beneficial indigenous bacteria, and can also be artificially and directionally implanted with beneficial bacteria, serving as an excellent carrier for microbial fertilizers to enhance their efficacy. It achieves synergistic effects of saline-alkali soil improvement, microbial activation, and soil structure reconstruction, specifically addressing the shortcomings of similar technologies in Japan, and has a wider range of applications.

Description

Technical Field

[0001] This invention relates to the field of soil amendment materials technology, specifically to an A / B dual-component soil granule with the functions of capturing, colonizing, reproducing and spreading indigenous bacteria, providing long-term nutrition, resisting pore blockage, providing precise pH buffering, disintegrating at set times throughout the year, and delivering to the root system. It is particularly suitable for the ecological restoration of special barren soils such as severely saline-alkali land, acidified soil, and acid rain-affected areas, as well as for the deep root soil improvement of economic crops such as fruit trees. It can also be applied to water purification-related fields such as aquaculture, urban ring water systems, and artificial wetlands. Background Technology

[0002] Modern farmland suffers from a sharp decline in soil microbial diversity, soil compaction, reduced nutrient retention, acidification, and increased disease due to the long-term excessive use of chemical fertilizers and pesticides. This is highly consistent with the technical background disclosed in Japanese Patent No. 5959712. This Japanese patent proposes the concept of "returning the land to agriculture of a thousand years ago," claiming that its volcanic clay filter material can "regenerate thousands of native soil bacteria that have disappeared in modern farmland," making the farmland environment "like a natural forest or grassland, no longer producing plant pathogens," and even eliminating pathogens in areas where infectious diseases such as downy mildew and wilt occur. Its core technical features include: adopting a porous structure similar to forest soil to capture airborne bacterial and fungal spores of 0.5-1μm; stabilizing the pH of the top 1cm layer at around 7.2 within one day of application, and improving it to a depth of 30-50cm within about 10 months; achieving pH buffering through a combination of "95% volcanic clay + 5% high-purity alkaline soil" ("strong acid + weak alkali"), claiming to be able to cope with acid rain or excessive alkalization; and using it by spreading it on the soil surface after planting, claiming that it is a one-time operation, relying on rainfall or soil moisture to carry the bacteria into the ground, without the need for repeated operations.

[0003] However, this Japanese patented technology has significant drawbacks and is unable to meet the comprehensive needs of modern soil remediation and water purification, especially the need for deep root system improvement in cash crops such as fruit trees:

[0004] Providing only a habitat without a long-term nutrient supply: The Japanese patented filter material relies solely on the physical structure of volcanic clay to provide attachment space for indigenous bacteria, creating an "acidic habitat." Without a dedicated nutrient supply system, it cannot provide a continuous source of carbon, nitrogen, and trace elements for the colonization and reproduction of the bacteria, thus limiting the efficiency of improving bacterial diversity and soil condition. As its technical description emphasizes, it only "captures airborne bacteria and supplies them to the soil," without mentioning the nutrient supply mechanism, making it difficult for the bacteria to achieve large-scale reproduction and enhanced ecological functions in the absence of exogenous nutrients.

[0005] The porous structure is easily clogged by polysaccharides, and surface application is susceptible to adverse weather conditions: The Japanese patent uses a single-pore size porous structure, claiming the pore size is comparable to bacterial size, but it fails to consider the extracellular polysaccharides (EPS) secreted by rapidly aggregated bacteria, which can cause pore blockage. Existing research shows that the high viscosity of EPS produced by microorganisms causes soil particles to bind tightly, significantly reducing porosity; porosity can decrease by 68.20% after 240 hours. Once the pores are clogged, the filter media loses its ability to capture and colonize bacteria. More importantly, its surface application method is vulnerable to dust storms, rain, and other adverse weather conditions, where splashed sludge can easily clog the filter media pores, drastically reducing the bacterial capture rate; furthermore, once the filter media is underground, the pores are easily filled with soil particles, completely losing its capture ability.

[0006] The pH buffering mechanism is simple and has limited adaptability: Japanese patents rely on a simple mixture of volcanic clay and alkaline soil to achieve buffering. Although it claims to be able to cope with acid rain and alkalization, it does not form a multi-component synergistic buffering system. Its buffering range is narrow and it is difficult to maintain a stable neutral environment in severely saline-alkali land (pH>8.5) or strongly acidified soil (pH<5.0). Moreover, volcanic clay resources are scarce and expensive.

[0007] Without active disintegration technology, the release of microbial communities and nutrients is limited and difficult to reach the root system: This technology lacks an active disintegration system, and the filter material relies solely on natural degradation in the soil, making the decomposition cycle completely uncontrollable. In the early stages, the microbial community can only colonize and spread within a small area around the particles. If decomposition is delayed, a large amount of nutrients and microbial communities will be locked inside the undegraded particles, unable to diffuse into deeper soil layers. If decomposition is premature, the microbial community is lost before it can form a stable community, making it difficult to build a dominant ecosystem. Furthermore, its reliance on rainfall or soil moisture to passively carry microbial communities into the ground has fatal flaws, including low migration efficiency and an inability to target and reach crop roots. For economic crops such as fruit trees with root systems distributed in the 50-80cm deep soil layer, it cannot achieve precise improvement around the root system and lacks mechanical adaptability for deep tillage machinery, rendering it ineffective in deep root soil management.

[0008] Uneven particle size leads to significant differences in application effects: The Japanese patented filter material uses a simple mixing and granulation process, resulting in a wide range of finished particle sizes, with a difference of up to 10 times. This leads to uneven distribution of particles in the soil after application. Large-diameter particles have a small improvement range and slow onset of action, while small-diameter particles are easily washed away by water flow, making it impossible to achieve uniform and efficient soil improvement. Furthermore, the uneven particle size further reduces its compatibility with agricultural machinery and equipment, making it difficult to achieve precise mechanized delivery.

[0009] Reasonable process for non-targeted microbial loading: The Japanese patent does not mention the exogenous microbial loading scheme. Even if you try to add microbial groups, the process design does not distinguish the timing of high temperature treatment and microbial loading, which will lead to microbial inactivation and fail to achieve the targeted improvement function.

[0010] Limited application scenarios: Japanese patented technologies focus only on farmland soil improvement and do not cover water purification fields such as aquaculture, urban water systems, and artificial wetlands. The functional coverage is narrow and it is difficult to meet the diverse needs of ecological restoration. Summary of the Invention

[0011] The purpose of this invention is to provide a soil regeneration granule integrating indigenous bacteria activation and soil improvement, as well as its preparation method and application, that comprehensively surpasses Japanese volcanic clay filter materials. Based on the Japanese patent's functions of "one-time operation, indigenous bacteria activation, and pH stability", it achieves advantages such as long-term nutrient supply, anti-pore clogging, wide-range pH buffering, precise disintegration, directional diffusion of bacteria, uniform and controllable particle size, targeted delivery to deep roots, guaranteed bacterial activity, and adaptability to multiple scenarios through innovative design. It truly realizes the synergistic effect of soil remediation and water purification, especially meeting the needs of deep root improvement for fruit trees and other economic crops and the purification needs of various water bodies.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: an integrated fertile soil core regeneration particle for indigenous bacteria activation and soil improvement and its preparation method, which adopts an A / B two-component layer structure, consisting of a disintegration triggering core, an A-component habitat layer, and a B-component functional layer from the inside out.

[0013] (I) Core Structure and Functional Design

[0014] Component A Habitat Layer: Gradient Porosity + Anti-Clogging, Optimizing the Microenvironment for Microbial Colonization. This invention inherits the core idea of ​​the Japanese patent "Porous Structure Capturing Indigenous Bacteria," but incorporates structural innovation: using activated rice husk silica and diatomaceous earth as the framework, a gradient porous structure is constructed through component particle size distribution, consisting of 0.5-1μm bacterial colonization pores and 1-2μm fungal spore colonization pores, with a pore connectivity rate ≥80%. This not only matches the particle size distribution of airborne microbial spores but also provides exclusive habitats for different types of microorganisms, promoting the coexistence of multiple bacteria like a "microbial apartment." Compared with the single-pore structure of the Japanese patent, this further enhances microbial diversity. To address the drawback of the porous structure in the Japanese patent being easily clogged by mucopolysaccharides, this invention achieves anti-clogging functionality through two main mechanisms: first, the synergistic effect of hydrogen-based bentonite and natural clinoptilolite, whose abundant ion exchange sites reduce the adsorption and deposition of negatively charged mucopolysaccharides on the pore walls; second, the gradient interconnected pore design allows for the rapid migration of microbial metabolites, preventing localized accumulation and clogging, ensuring long-term unobstructed pores, and solving the problem of functional degradation after long-term use of the Japanese patented filter material.

[0015] Component B Functional Layer: Long-lasting nutrient supply and construction of a microbial ecological cycle. This is one of the core advantages of this invention compared to the Japanese patent. The Japanese patent only provides physical attachment space for the microbial community, while this invention constructs a "long-lasting nutrient supply system" through the Component B functional layer: rice husk biochar (specific surface area ≥300m² / g) works synergistically with humic acid in Component A, not only adsorbing nutrient ions in the soil, but also slowly releasing carbon, nitrogen, phosphorus, potassium, and trace elements, providing continuous nutritional support for the entire cycle of microbial colonization, reproduction, and diffusion. This dual guarantee of "space + nutrition" enables this invention not only to "capture indigenous bacteria" but also to "nurture indigenous bacteria," truly realizing the "reproduction of the natural reproduction process of microbial communities during the decomposition of fallen leaves in forests" claimed by the Japanese patent, and its reproduction efficiency and ecological stability far exceed those of the Japanese filter material. Meanwhile, oyster shell powder and rice husk biochar in component B work synergistically to enhance pH buffering performance; polycaprolactone micro powder, as a time-controlled material, works with the internal disintegration trigger core to achieve precise disintegration over 12 months; stearic acid-modified bentonite forms a hydrophobic protective layer to delay the rapid intrusion of moisture and ensure early structural stability.

[0016] Disintegration Triggering Core: Precise Disintegration + Directed Microbial Diffusion, Overcoming the Limitations of Japanese Patent Technology. The disintegration triggering core is the core innovation of this invention, composed of citric acid microcapsules, sodium bicarbonate, and hydroxypropyl methylcellulose, specifically addressing the key deficiency of the lack of active disintegration technology in the Japanese patent. The citric acid microcapsules use gelatin-gum arabic composite wall material, with a particle size of 10-20μm and an encapsulation rate ≥80%. The release rate in soil is ≤10% in the first 11 months. After 12 months, it synergistically interacts with the outer polycaprolactone micropowder, causing the capsule wall to rupture and release citric acid, which then reacts rapidly with sodium bicarbonate to produce CO2 gas. This system achieves a dual microbial release mode of "continuous release + centralized delivery": For the first 11 months, the gradient porous structure of the particles provides a stable habitat for native bacteria, while rice husk biochar and humic acid continuously supply nutrients. The microbial community will spontaneously and slowly diffuse into the surrounding soil through the pore channels, gradually building a basic microbial community. At 12 months, the polycaprolactone wall material degrades and breaks down, and water invades the trigger core. The gas-producing reaction forms directional pressure inside the particles, which on the one hand breaks down the weakened particle skeleton, and on the other hand, uses gas as a carrier to actively push the highly active microbial community and nutrients enriched in the particles to the deeper soil layer within a range of 5-8 cm. This design avoids the drawbacks of the Japanese patent, such as "nutrient lock-in due to late disintegration and microbial community loss due to premature disintegration," and also solves the problem that "the microbial community is limited to the periphery of the particles," achieving a dual optimization of the temporal synergy and spatial expansion of particle function and microbial ecology.

[0017] Wide-range pH buffering system: Resisting acid rain and over-alkalization, adaptable to various soil types. This invention inherits the advantage of the Japanese patent's "pH stability near neutrality" and constructs a more powerful synergistic buffering system: Component A, hydrogen-based bentonite and natural clinoptilolite, provide ion exchange buffering, while component B, oyster shell powder and rice husk biochar, provides acid-base neutralization buffering, forming a dual buffering mechanism of "mineral colloid exchange + organic-inorganic neutralization." This expands the overall pH buffering range of the particles to 6.0-8.0, far exceeding the buffering range of the Japanese patent. Whether it is strongly acidic soil with pH < 5.0, severely saline-alkali land with pH > 8.5, or soil affected by acid rain, this invention can quickly stabilize the pH of the top 1cm of soil at 7.2 ± 0.2 and maintain pH stability in deeper soil layers, truly achieving an effective response to acid rain and over-alkalization. In contrast, the Japanese patent relies only on a simple mixture of volcanic clay and a small amount of alkaline soil, which has limited buffering effect in extreme pH soils.

[0018] Precise Particle Size Control Technology: Uniform Particle Size, Adapted for Mechanized Targeted Delivery. Addressing the issue of uneven particle size (up to 10 times) in Japanese patented filter media, this invention employs a layered coating granulation process. A rounding machine precisely controls the particle size at each stage: the trigger core particle size is 1mm, the intermediate particle size after A-component coating is 2.5mm, and the final product particle size after B-component coating is precisely controlled between 3-3.5mm, with a particle size deviation ≤0.2mm. Uniform particle size ensures even distribution of particles in the soil after application, with each particle exhibiting highly consistent improvement range, disintegration time, and functional release rhythm, avoiding the "over-improvement in some areas, under-improvement in others" problem caused by particle size differences in Japanese patented filter media. More importantly, the uniform particle size gives the particles excellent mechanical adaptability, which can be directly delivered to the root soil layer of fruit trees and other cash crops at a depth of 50-80cm by deep tillage machines to achieve targeted root improvement; while the Japanese patented filter material with uneven particle size cannot be adapted to mechanized deep delivery, and after being spread on the ground, it relies on the passive migration of rainfall, which cannot accurately reach the deep root area and cannot meet the deep soil improvement needs of fruit trees and other cash crops.

[0019] Targeted Microbial Loading Process: Optimized Timing to Ensure Microbial Activity. Addressing the deficiency in Japanese patents regarding the lack of a suitable microbial loading scheme, this invention adds a targeted microbial loading step and optimizes the process timing: microbial loading is performed after low-temperature heat treatment and particle cooling. The upper limit of the survival temperature for conventional functional microbial communities (Bacillus subtilis, phosphate-solubilizing bacteria, etc.) is 80-120℃. Low-temperature heat treatment at 350℃ will damage the cell membrane and genetic material of the microbial community, leading to inactivation. Therefore, loading at room temperature after heat treatment can completely preserve the biological activity of the microbial community. The loaded targeted microbial community can directly colonize and reproduce around the root system of fruit trees, working synergistically with native bacteria to rapidly build a stable microbial ecosystem in extreme environments, achieving the dual goals of "disease disappearance" and soil fertility. Simultaneously, the specific functional microbial community can also enhance the degradation capacity of pollutants such as nitrogen and phosphorus in water bodies, improving water purification effects.

[0020] The granules of this invention possess bidirectional microbial regulation capabilities, capable of capturing beneficial indigenous bacteria in the air and promoting their colonization and reproduction within the granule's microenvironment. They can also be artificially implanted with various beneficial soil bacteria. Application methods include surface spreading, topsoil mixing, and targeted delivery to the root zone using deep tillage equipment. This achieves synergistic effects of saline-alkali soil improvement, activation of beneficial indigenous bacteria, and soil structure reconstruction. As an excellent carrier for microbial fertilizers, this invention provides a favorable environment for the survival and growth of microbial fertilizer strains, significantly enhancing the fertilizer's efficacy. Surface spreading involves directly and evenly spreading the granules on the surface of saline-alkali soil, combined with shallow tillage, to regulate surface soil salinity and activate indigenous bacteria. Topsoil mixing involves thoroughly mixing the granules with the saline-alkali soil topsoil at a preset ratio, improving the soil's physicochemical properties and creating a suitable soil microenvironment for crop growth. Targeted root reconstruction uses deep tillage equipment to precisely deliver the granules to the soil area around tree roots, achieving targeted soil improvement and promoting root growth and nutrient absorption.

[0021] (II) Synergistic effect between gas-producing disintegration system and soil microenvironment

[0022] The "citric acid microcapsule + sodium bicarbonate" gas-generating disintegration system proposed in this invention is not a single particle disintegration driving unit, but a multifunctional synergistic module deeply coupled with the soil microenvironment. Its innovation lies in the organic integration of four major functions: precise disintegration, mild chemical modification, micro-domain physical loosening, and directional diffusion of microbial communities. This achieves a benign interaction between particle function and soil ecology. The specific synergistic mechanism is as follows:

[0023] The precise synergy between the disintegration sequence and the release rhythm of the microbial community overcomes the limitations of the Japanese patent's natural decomposition method. The gas-producing disintegration process of this system is strictly controlled by the slow-release performance of the citric acid microcapsules and the hydrolysis cycle of the outer polycaprolactone layer. The precise 12-month disintegration cycle highly coincides with the colonization, reproduction, and diffusion cycle of soil microorganisms within the particle pores. The continuous diffusion of the microbial community in the first 11 months builds the basic microbial community for the soil; the concentrated delivery over the 12 months transports highly active microorganisms and nutrients to the deeper soil layers, forming an ecological construction rhythm of "early colonization and later expansion," completely avoiding the uncontrollability of the Japanese patent's natural decomposition method.

[0024] The gas production reaction and soil pH regulation involve a mild synergistic neutralization reaction of citric acid and sodium bicarbonate, a micro-domain controllable reaction within the micropores of the particles. The trace amounts of CO2 generated dissolve in soil water to form weak carbonic acid, which can temporarily lower the pH of the rhizosphere microenvironment in alkaline soils, gently dissolving fixed, insoluble phosphates, potassium feldspar, and other minerals in the soil, releasing available nutrients. The reaction product, sodium citrate, as a natural organic acid salt, serves as both a high-quality carbon source for microorganisms and a chelating agent to activate trace elements such as calcium, magnesium, and iron in the soil, improving soil nutrient availability. Compared to the strong acid-base regulation of traditional chemical amendments, the modifying effect of this system is limited to the micro-domain space around the particles, without causing drastic fluctuations in the overall soil pH.

[0025] The dynamic synergistic gas production reaction between gas emission and soil physical structure improvement generates CO2, which rapidly accumulates pressure within the micropores of the particles. This pressure breaks down the particle skeleton, and the gas escapes into the surrounding soil along the pore channels, creating minute "airflow disturbances" within the micro-domain. This effectively breaks down the adhesion between soil particles, reduces compaction, and increases soil porosity. The fine organic-inorganic composite particles formed after particle disintegration combine with the microchannels left by gas emission, further optimizing soil aggregate structure and improving soil aeration and water retention. This dual physical improvement of "gas production disturbance + particle pulverization" provides a more suitable environment for microbial community diffusion, forming a positive cycle of "physical improvement - biological activity."

[0026] (III) Water purification principle

[0027] The integrated fertile soil granules of this invention provide water purification functionality based on a synergistic mechanism of microbial dominance, physical adsorption, chemical buffering, and controlled-time release. Through multi-dimensional functional coupling, it achieves efficient removal of water pollutants and regulation of microecological balance. The specific principle is as follows:

[0028] The microbial targeted degradation (core function) particle A component's habitat layer features a 0.5-2μm gradient porous structure, which efficiently captures indigenous denitrifying bacteria, polyphosphate-accumulating bacteria, and organic matter-degrading bacteria in the water. Simultaneously, the ion exchange sites of hydrogen-based bentonite and natural clinoptilolite inhibit pore blockage caused by the secretion of mucopolysaccharides from the bacteria, providing a stable microenvironment for bacterial colonization. The rice husk biochar (specific surface area ≥300m² / g) in the B component functional layer synergistically releases carbon sources, nitrogen, phosphorus, and trace elements, meeting the nutritional needs of the bacteria throughout their entire life cycle and enhancing their metabolic activity. Targeted functional bacteria (nitrifying / denitrifying bacteria, Bacillus subtilis, etc.) can be used to selectively degrade pollutants such as ammonia nitrogen, nitrite, COD, and BOD5 in water bodies for different water purification scenarios: nitrifying bacteria convert ammonia nitrogen into nitrate, and denitrifying bacteria further reduce nitrate to N2 and release it; polyphosphate-accumulating bacteria excessively absorb phosphorus from the water and store it in their cells; heterotrophic bacteria decompose large organic molecules into small harmless substances, ultimately achieving water purification.

[0029] The activated rice husk silica and diatomaceous earth of component A and the rice husk biochar of component B possess a rich porous structure and a huge specific surface area. They can retain suspended solids (SS), colloidal particles and some heavy metal ions in water through physical adsorption. At the same time, the uniformly sized particles can form a stable "biofilter bed" in the water, improve the pollutant retention efficiency and reduce the turbidity of the water.

[0030] The dual pH buffering system of chemical buffering and microenvironment regulation particles, combining "mineral colloid exchange + organic-inorganic neutralization," can stabilize the pH of water within a suitable range of 6.0-8.0. This system is suitable for extreme water environments such as salinization and acidification, while also ensuring the metabolic activity of functional microbial communities. During the 12-month precise disintegration phase, the weak carbonic acid generated by the reaction of citric acid microcapsules and sodium bicarbonate can gently dissolve insoluble phosphates in the water, improving the bioavailability of phosphorus. The reaction product, sodium citrate, acts as a natural chelating agent, activating trace elements in the water and preventing them from binding with pollutants to form precipitates.

[0031] For the first 11 months, the controlled release and expanded purification range allow the granules to maintain a stable structure, with the bacterial community slowly diffusing into the surrounding water through pores, achieving continuous purification. At 12 months, the polycaprolactone micropowder degrades and breaks down, allowing moisture intrusion to trigger a gas-generating reaction. CO2 gas actively propels the highly active bacteria and nutrients accumulated within the granules to a 7-8cm water surface, expanding the purification radius and overcoming the limitations of traditional materials. The granules undergo low-temperature heat treatment to strengthen their structure, resulting in slow disintegration in water without large residues, preventing secondary clogging and pollution. This makes them suitable for diverse applications such as aquaculture, urban water systems, and constructed wetlands.

[0032] The indigenous bacteria activation-soil improvement integrated soil core regeneration granules are a type of integrated soil core regeneration granules that can inherit the core advantages of "one-time application, capture of indigenous bacteria, and pH buffering" while making up for its shortcomings such as insufficient nutrient supply, weak anti-clogging ability, narrow buffer range, uncontrollable disintegration, uneven particle size, inability to target root delivery, lack of microbial loading technology, and limited application scenarios.

[0033] (iv) Key points of preparation method

[0034] The core of the preparation method of this invention lies in the layered coating granulation process, the precise preparation of citric acid microcapsules, the construction of a gradient porous structure, precise particle size control, mechanical compatibility assurance, and the optimization of microbial loading sequence. It also clearly distinguishes the functions of segmented drying and low-temperature heat treatment.

[0035] Layered coating granulation and particle size control: A 1mm trigger core is prepared by screw extruder, and then components A and B are coated in two steps by rounding machine. The particle size of intermediate and finished products is precisely controlled to ensure that the final particle size is 3-3.5mm and uniform. This not only solves the defect of uneven particle size in the Japanese patent, but also gives the particles mechanical properties suitable for deep tillage machines.

[0036] Citric acid microcapsule preparation: By strictly controlling the complex coagulation reaction and cross-linking with glutaraldehyde at pH 4.0-4.2, the sustained-release performance is ensured to be stable, with citric acid release ≤10% within 11 months and ≥85% within 12 months.

[0037] Distinguishing between segmented drying and low-temperature heat treatment

[0038] Segmented drying: Component A is dried at 60℃ for 4 hours after coating, and component B is dried at 70℃ for 3 hours after coating. The purpose is to remove the moisture introduced during the coating process, ensure the stability of the structure of each layer, and lay the foundation for subsequent heat treatment.

[0039] Low-temperature heat treatment: The pre-finished product after coating and drying is heated to 200-350℃ at 5℃ / min and held for 2 hours. This is to strengthen the interfacial bonding strength between components A and B, stabilize the gradient porous structure, and prevent pore collapse. At this temperature, the gelatin-arabinose capsule wall cross-linked with glutaraldehyde has excellent thermal stability and will not damage the structure and sustained-release performance of the citric acid microcapsules. Actual tests have verified that the microcapsule encapsulation rate is still ≥78% after heat treatment.

[0040] Targeted microbial loading timing optimization: Microbial loading is carried out after low-temperature heat treatment and particle cooling to room temperature, using immersion or spraying of functional bacterial solution. Specific parameters are: stand for 2 hours, air dry in the shade at 25-30℃ in a dark and ventilated environment for 4-6 hours to avoid high temperature and exposure to sunlight that could cause microbial inactivation, thus ensuring the dual goals of microbial bioactivity and particle structural stability.

[0041] Beneficial effects

[0042] This invention fully inherits and surpasses the core functions of Japanese Patent No. 5959712, while overcoming many of its shortcomings, resulting in significant advantages:

[0043] With more comprehensive functions, this invention achieves five-fold protection: space, nutrition, diffusion, targeting, and live bacteria. While Japanese patents only provide microbial colonization space and rely on passive migration, failing to reach the root system directly and lacking a live bacteria loading solution, this invention adds a long-lasting nutrient supply system, a directional diffusion mechanism for microbial communities, deep-targeted delivery capabilities, and a time-optimized live bacteria loading process. This solves the problems of "difficult colonization, slow reproduction, short diffusion, inability to target the root system, and difficulty in ensuring activity" for microbial communities, truly achieving the technical goal of "regenerating thousands of native soil bacteria + synergistic improvement of exogenous targeted microbial communities." It is particularly suitable for deep root system improvement of fruit trees and other economic crops, offering a more lasting and significant improvement effect than Japanese filter materials. This invention possesses bidirectional microbial regulation capabilities, capable of capturing beneficial native bacteria in the air and promoting their colonization and reproduction within the granular microenvironment, as well as directionally implanting various beneficial soil bacteria through artificial loading. Simultaneously, as an excellent carrier for microbial fertilizers, it provides a favorable environment for the survival and growth of microbial fertilizer strains, greatly enhancing the efficacy of microbial fertilizers.

[0044] More stable structure, outstanding anti-clogging ability and resistance to harsh weather: Through the synergistic effect of gradient porous structure and ion exchange components, it effectively inhibits pore clogging caused by microbial mucopolysaccharides; at the same time, the uniform particle size and stable structure avoid the pore clogging problem caused by sand and rain in the Japanese patented filter material, ensuring that the particles continue to play a role in the soil, and the advantage of not needing to be reapplied is more stable.

[0045] With stronger pH buffering capacity and a wider range of applicability: It constructs a dual buffering system, extending the buffering range to 6.0-8.0. It can not only stabilize pH in ordinary acidic and alkaline soils, but also play a stable role in extreme pH soils such as severely saline-alkali soils and acidified soils, as well as soils affected by acid rain. This overcomes the shortcomings of the Japanese patent in terms of limited buffering effect in extreme environments.

[0046] Precise and controllable disintegration enables deep diffusion of microbial communities: A precise disintegration mechanism and gas delivery function over 12 months allow for the concentrated release and diffusion of microbial communities and nutrients to a depth of 5-8cm in the soil. Combined with mechanized targeted delivery, particles can be directly delivered to the root layer of fruit trees at a depth of 50-80cm. This method achieves deeper soil improvement more quickly than the Japanese patented natural degradation + passive migration method, leaving no lumpy residue. Its application methods include surface spreading, topsoil mixing, and targeted delivery to the area around tree roots using deep tillage equipment. It achieves synergistic effects of saline-alkali soil improvement, activation of native beneficial bacteria, and soil structure reconstruction.

[0047] Uniform and controllable particle size, suitable for mechanized operations: The finished particles have a diameter of 3-3.5mm and a deviation of ≤0.2mm. They are evenly distributed after application, and the improvement range and rhythm are consistent, solving the problem of uneven application effect caused by the 10-fold difference in particle size of the Japanese patented filter material. At the same time, its excellent mechanical adaptability fills the technical gap that the Japanese patent cannot achieve deep root targeted improvement.

[0048] Low-cost raw materials and easy industrialization: Using agricultural waste and natural minerals such as rice husk silica, diatomaceous earth, and oyster shell powder as raw materials, it replaces the volcanic clay that is scarce in Japanese patents, and the availability of raw materials is not limited; the low-temperature heat treatment process reduces energy consumption by more than 60% compared with the processing process of Japanese patents, significantly reducing production costs and making it more conducive to large-scale promotion.

[0049] With a wider range of applications, this invention enables synergistic soil-water remediation: Based on a synergistic water purification mechanism of microbial dominance, physical adsorption, chemical buffering, and controlled-release, this invention is not only applicable to disease prevention and soil regeneration in ordinary farmland, and special soil improvement such as severely saline-alkali land and acidified soil, but can also be extended to aquaculture water purification, urban ring water system water purification, and artificial wetland wastewater treatment. In aquaculture water, the ammonia nitrogen removal rate reaches 89% and the total phosphorus removal rate reaches 76%, while in urban ring water systems, the COD removal rate reaches 72%, and the effluent can meet the Class IV surface water standard. Its application scenarios far exceed those of the Japanese patent that only focuses on the surface improvement of farmland; especially for the deep root system improvement needs of fruit trees and other cash crops, it has irreplaceable technical advantages. Attached Figure Description

[0050] Figure 1 Process flow diagram

[0051] Figure 2 Schematic diagram of integrated fertile soil granular layered structure and particle size

[0052] Figure 3 Particle Function Implementation and Targeted Delivery Flowchart

[0053] Figure 4 Particle mass loss versus time curve in accelerated aging experiment

[0054] Figure 5 Comparison chart of the diffusion range of particulate bacteria

[0055] Figure 6 Comparison chart of particle anti-clogging performance

[0056] Figure 7 Comparison chart of particle application scenarios

[0057] Marker description

[0058] Figure 2 Structural labeling: 1-Disintegration triggering core (particle size 1mm); 2-Component A habitat layer; 3-Component B functional layer; 4-Citrate microcapsules; 5-Sodium bicarbonate; 6-Hydroxypropyl methylcellulose; 7-Activated rice husk silica; 8-Diatomaceous earth; 9-Hydrogen-based bentonite; 10-Rice husk biochar; 11-Oyster shell powder; 12-Polycaprolactone micro powder; Finished product particle size 3-3.5mm.

[0059] Attached image description: Figure 2This diagram illustrates the three-layer spherical structure and particle size control of the integrated fertile soil particles of this invention. The core is a disintegration triggering core containing uniformly dispersed citric acid microcapsules, which, together with sodium bicarbonate and hydroxypropyl methylcellulose, constitute a gas-generating expansion and microbial community propulsion system. The middle layer is the A-component habitat layer, a concentrated area of ​​a 0.5-2μm gradient porous structure, containing bacterial colonization pores and fungal spore colonization pores, undertaking the functions of capturing indigenous bacteria, pH buffering, and anti-clogging. The outer layer is the B-component functional layer, which combines hydrophobic protection, long-term nutrient supply, and time-controlled disintegration. The diagram clearly marks the particle size at each stage, intuitively demonstrating the advantages of the precise particle size control of this invention, and highlighting the shortcomings of the Japanese patent in terms of uneven particle size.

[0060] Figure 3 Process labeling: 1. Particle cooling after low-temperature heat treatment; 2. Targeted microbial community immersion / spray loading at room temperature; 3. Targeted delivery by deep tillage machine (50-80cm root layer) / water addition; 4. Indigenous bacteria capture stage; 5. Continuous diffusion stage of microbial community; 6. Citric acid microcapsule rupture and gas production; 7. Precise particle disintegration + directional delivery of microbial community to the root periphery / pollutant degradation.

[0061] Attached image description: Figure 3 This is a schematic diagram illustrating the functional implementation and targeted delivery process of the integrated fertile soil particles of the present invention. It clearly demonstrates the optimization of the microbial loading sequence, the two loading methods of immersion / spraying, the multiple application paths of mechanized deep delivery and water addition, and the entire process of directional diffusion of microbial communities. It highlights the advantages of the present invention in ensuring microbial activity, targeted root system improvement and water purification, and contrasts it with the technical shortcomings of the Japanese patent, such as passive migration, no live bacteria loading, and limited application scenarios.

[0062] Figure 4 Coordinate axis labels: Horizontal axis - accelerated aging time (days); Vertical axis - particle mass loss rate (%); Curve 1 - particles of the present invention; Curve 2 - Japanese volcanic clay filter material.

[0063] Attached image description: Figure 4 This figure shows a comparison of the accelerated aging performance of the integrated fertile soil particles of this invention and Japanese volcanic clay filter media. Curve 1 shows that under conditions of 40℃ and 85% humidity, the particles of this invention experience slow mass loss (cumulative 30%) in the first 45 days, and enter a rapid disintegration stage (cumulative loss of 65%) from 45 to 60 days due to the rupture of citric acid microcapsules and gas production, corresponding to a precise 12-month disintegration cycle in the field. Curve 2 shows that the mass loss of the Japanese filter media does not have obvious stage characteristics, and its natural degradation cycle is uncontrollable. This figure visually verifies the precise controllability of the particle disintegration sequence of this invention, highlighting its advantages over Japanese technology.

[0064] Figure 5 Coordinate axis labels: Horizontal axis - soil burial time (months); Vertical axis - microbial diffusion radius (cm); Curve 1 - particles of this invention; Curve 2 - Japanese volcanic clay filter material.

[0065] Attached image description: Figure 5 The graph shows a comparison of the microbial diffusion range between the integrated fertile soil particles of this invention and Japanese volcanic clay filter media. Curve 1 shows that after 12 months of burial, the microbial diffusion radius of the particles of this invention reaches 7-8 cm with the help of gas generation; Curve 2 shows that the microbial diffusion radius of the Japanese filter media, relying solely on natural diffusion, is only about 2 cm. This graph clearly demonstrates the significant advantage of the particles of this invention over Japanese technology in terms of deep microbial diffusion.

[0066] Figure 6 Coordinate axis labels: Horizontal axis - immersion time under simulated severe weather (days); Vertical axis - pore blockage rate (%); Curve 1 - particles of this invention; Curve 2 - Japanese volcanic clay filter material.

[0067] Attached image description: Figure 6 The graph shows a comparison of the anti-clogging performance of the integrated fertile clay particles of this invention and Japanese volcanic clay filter media. Curve 1 shows that after immersion in simulated sandstorm and rainfall environments for 30 days, the pore clogging rate of the particles of this invention is only 8%, demonstrating the synergistic anti-clogging effect of the gradient porous structure and ion exchange components. Curve 2 shows that the pore clogging rate of the Japanese filter media reaches 35% during the same period, easily losing its native bacteria capture function. This figure clearly demonstrates the structural stability advantage of the particles of this invention compared to the Japanese technology.

[0068] Figure 7 Labeling content: Left side - Particles of this invention (particle size 3-3.5mm, deviation ≤0.2mm; can be targeted to the root layer of 50-80cm, live bacteria survival rate ≥88%; application scenarios: ordinary farmland, saline-alkali land, acidified soil, aquaculture, urban ring water system, artificial wetland); Right side - Japanese patented filter material (large particle size range, difference up to 10 times; can only be passively migrated by spreading on the ground, without effective process for live bacteria loading; application scenarios: limited to the improvement of farmland surface soil).

[0069] Attached image description: Figure 7 This image compares the particle size uniformity, application method, microbial load effect, and application scenarios of the integrated soil granules of this invention with those of the Japanese patented filter media. On the left, the particles of this invention are of uniform size, suitable for mechanized deep delivery and diverse application scenarios, while ensuring the activity of live bacteria. On the right, the Japanese filter media has inconsistent particle sizes, making it unable to achieve targeted root system improvement, and its application is limited to the surface layer of farmland. This image visually demonstrates the significant advantages of this invention in terms of adaptability to all scenarios. Detailed Implementation

[0070] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0071] Example 1

[0072] A native bacteria activation-soil improvement integrated soil core regeneration particle and its preparation method are disclosed. By weight, the disintegration triggering core includes 3 parts of citric acid microcapsules, 2 parts of sodium bicarbonate, and 5 parts of hydroxypropyl methylcellulose; the A-component habitat layer includes 20 parts of activated rice husk silica, 25 parts of diatomaceous earth, 8 parts of hydrogen-based bentonite, 5 parts of natural clinoptilolite, and 6 parts of humic acid; the B-component functional layer includes 15 parts of rice husk biochar, 10 parts of oyster shell powder, 2 parts of sodium lignosulfonate, 1 part of polycaprolactone micropowder, and 8 parts of stearic acid-modified bentonite.

[0073] Its preparation method includes the following steps:

[0074] Preparation of citric acid microcapsules: ① Weigh 5g each of gelatin and gum arabic, add them to two beakers containing 100mL of deionized water, and stir at 50℃ for 30min until completely dissolved to obtain a 5% gelatin-gum arabic composite wall material solution; ② Weigh 10g of 200-mesh citric acid powder and add it to the wall material solution, emulsify at 9000rpm for 15min, add 1mL of glycerol and stir for 10min; ③ Maintain 50℃ and adjust the pH of the system with 10% hydrochloric acid. H to 4.1, constant temperature stirring for 30 min to form blastocysts, naturally cooled to 25℃, then cooled to below 5℃ in an ice-water bath and kept at that temperature for 30 min; ④ 2 mL of 25% glutaraldehyde solution was added dropwise under stirring in an ice-water bath, crosslinked for 60 min, washed successively with deionized water and anhydrous ethanol, vacuum dried at 40℃ for 8 h, and citric acid microcapsules were obtained by sieving through a 200-mesh sieve; the obtained microcapsules had a particle size of 15 μm, an encapsulation rate of 82%, a citric acid release of 8% after 11 months, and a release of 88% after 12 months.

[0075] Preparation of disintegration triggering core: Citric acid microcapsules, sodium bicarbonate and hydroxypropyl methylcellulose were mixed evenly and extruded into small particles with a diameter of 1 mm using a screw extruder. The particles were then dried at 40°C for 2 hours for later use.

[0076] Preparation of component A habitat layer slurry: Activated rice husk silica, diatomaceous earth, hydrogen-based bentonite, natural clinoptilolite, and humic acid were dry-mixed for 10 min according to the specified ratio. A 1.5% sodium alginate solution was added, and the solid-liquid ratio was adjusted to 1:0.8. The mixture was stirred for another 20 min to form a viscous slurry. A 0.5-2 μm gradient porous structure was constructed by grading the particle size of the raw materials (200 mesh activated rice husk silica and 300 mesh diatomaceous earth).

[0077] Component A coating trigger core: The disintegration trigger core particles were fed into a spheroidizing machine, the spheroidizing speed was set to 30 r / min, the Component A slurry was spray-coated, and the particles were spheroidized to a particle size of 2.5 mm. They were then transferred to a 2% calcium chloride solution for crosslinking for 30 min, and dried at 60 °C for 4 h to obtain intermediate particles.

[0078] Preparation of component B functional layer coating powder: Rice husk biochar, oyster shell powder, and sodium lignosulfonate were dry-mixed for 10 min, and then polycaprolactone micro powder and stearic acid modified bentonite were added. The mixture was continued for 15 min to prepare a uniform coating powder. Among them, the rice husk biochar was pre-carbonized at 600℃, and the specific surface area reached 320 m² / g.

[0079] Component B coating intermediate: The intermediate particles are placed in a spheroidizing machine, sprayed with 1.5% sodium alginate binder, and simultaneously coated with component B coating powder. The particles are spheroidized to a particle size of 3 mm and dried at 70°C for 3 hours to ensure that the coating powder adheres firmly to the surface of the intermediate.

[0080] Low-temperature heat treatment: The coated particles were placed in a box-type resistance furnace and heated to 200°C at a heating rate of 5°C / min. The temperature was maintained for 2 hours and then naturally cooled to room temperature to avoid pore collapse and nutrient inactivation caused by high temperature. The encapsulation rate of citric acid microcapsules was 79% after heat treatment.

[0081] Targeted microbial loading (optional): Immerse or spray the cooled finished product granules with a compound bacterial solution of Bacillus subtilis and phosphate-solubilizing bacteria (concentration 1×10⁻⁶). 8 (CFU / mL), let stand for 2 hours, then remove and air dry in a dark and ventilated environment at 28℃ for 5 hours to complete the bacterial loading.

[0082] Performance testing

[0083] Particle size uniformity and mechanical compatibility: The finished particles have a diameter of 3.0±0.1mm and a deviation of ≤0.2mm, which can pass smoothly through the pipes of deep-tillage machines without clogging; this is far superior to the 10-fold particle size difference of Japanese filter media.

[0084] Pore ​​structure and anti-clogging performance: 32% of the finished particles have a pore size of 0.5-1μm, 26% have a pore size of 1-2μm, and the total pore connectivity rate is 85%. After 30 days of immersion in simulated sand and rain environments, the pore clogging rate is only 8%, which is far lower than the 35% clogging rate of Japanese volcanic clay filter material during the same period.

[0085] pH buffering capacity:

[0086] Saline-alkali soil test: Severely saline-alkali soil with pH 8.9 was introduced. After 1 day, the pH of the top 1 cm soil stabilized at 7.1. After 24 hours, the EC value dropped from 450 μs / cm to 310 μs / cm. After continuous monitoring for 60 days, the soil pH remained at 7.0-7.3, and no alkali return phenomenon was observed.

[0087] Acid rain simulation test: When simulated acid rain with pH 4.0 was continuously leached, the soil pH in the granular treatment group remained stable at 6.8-7.2, and no acidification occurred; the soil pH in the blank control group dropped to 5.2.

[0088] Disintegration performance and microbial diffusion: In the accelerated aging test at 40℃ and 85% humidity, the mass loss was 30% in the first 45 days, and the mass loss rate accelerated from 45 to 60 days, with a cumulative loss of 65%; After being delivered to the root layer of fruit trees at a depth of 80cm by a deep tillage machine and buried for 12 months, the pulverization rate of the particles reached more than 95%, with no lumpy residue, and the microbial diffusion range reached 7cm, far exceeding the 2cm diffusion range of Japanese filter materials; The soil organic matter content within 5cm of the pulverized area increased to 1.2%.

[0089] Microbial activity and improvement effect:

[0090] Indigenous bacteria capture: After 7 days of air exposure, the total number of bacteria on the particle surface reached 1.1 × 10⁻⁶. 6 CFU / g, total fungal count reached 1.3×10 6 The CFU / g microbial diversity index reached 2.8, which is higher than the 2.1 of Japanese filter media.

[0091] Exogenous microbial activity: After the loaded microbial community was air-dried, the survival rate of live bacteria reached 92%; after being delivered to the 80cm deep root layer of apple orchard for 6 months, the number of beneficial microbial communities in the soil around the roots increased by 15 times, the soil compaction decreased by 40%, and the number of fibrous roots of apple trees increased by 25%.

[0092] Water purification effect: After 15 days, the ammonia nitrogen removal rate of the granules loaded with nitrifying and denitrifying bacteria was 89%, the total phosphorus removal rate was 76%, and the water transparency was increased to 1.2m.

[0093] Example 2

[0094] A native bacteria activation-soil improvement integrated soil core regeneration particle and its preparation method are disclosed. By weight, the disintegration triggering core includes 4 parts of citric acid microcapsules, 3 parts of sodium bicarbonate, and 6 parts of hydroxypropyl methylcellulose; the A-component habitat layer includes 25 parts of activated rice husk silica, 30 parts of diatomaceous earth, 10 parts of hydrogen-based bentonite, 6 parts of natural clinoptilolite, and 8 parts of humic acid; the B-component functional layer includes 20 parts of rice husk biochar, 12 parts of oyster shell powder, 3 parts of sodium lignosulfonate, 2 parts of polycaprolactone micropowder, and 10 parts of stearic acid-modified bentonite.

[0095] Its preparation method is the same as in Example 1, except that:

[0096] When preparing citric acid microcapsules, the pH of the complex coagulation was adjusted to 4.0 and the cross-linking time was extended to 70 min. The resulting microcapsules had an encapsulation rate of 85% and a citric acid release rate of 90% after 12 months.

[0097] The low-temperature heat treatment temperature was raised to 350℃ and held for 2 hours to further enhance the mechanical strength of the particles and improve the adsorption performance of rice husk biochar; the microcapsule encapsulation rate after heat treatment was 78%.

[0098] After coating with component B, the particle size is 3.5 mm with a particle size deviation of 0.2 mm.

[0099] The bacterial culture was air-dried at 25℃ for 6 hours, and the survival rate of live bacteria reached 90%.

[0100] Performance testing

[0101] Particle size uniformity and mechanical compatibility: The finished particles have a particle size of 3.5±0.2mm, which is suitable for deep-tillage machines for deep delivery without breakage.

[0102] Pore ​​structure: 62% of the pores are between 0.5 and 2 μm in diameter, the pore connectivity is 88%, and the pore blockage rate is only 6% after 30 days of immersion in simulated severe weather.

[0103] pH buffering capacity: When saline-alkali soil with pH 9.1 is introduced, the pH of the top 1cm layer stabilizes at 7.2 after 1 day and remains at 7.1-7.4 within 60 days; after simulated acid rain leaching, the soil pH stabilizes at 6.9-7.3.

[0104] Disintegration performance and microbial diffusion: After 60 days of accelerated aging, the mass loss is 68%. When applied to the citrus root layer at a depth of 50cm in the field, the pulverization rate reaches 98% after 12 months, and the microbial diffusion range reaches 8cm. The soil improvement depth within 5cm is increased to 8cm.

[0105] Application results: When applied to acidified tea garden soil with pH 5.0, the soil pH recovered to 6.8 after 30 days, the incidence of tea root rot decreased from 28% to 3%, and the amino acid content of tea increased by 15%. When used for the purification of urban ring water systems, the COD removal rate of water reached 72% after 20 days, and the water quality met the Class IV standard for surface water.

[0106] Example 3

[0107] An integrated fertile soil granule suitable for water purification in aquaculture, comprising, by weight, a disintegration triggering core including 5 parts of citric acid microcapsules, 2.5 parts of sodium bicarbonate, and 4 parts of hydroxypropyl methylcellulose; a habitat layer A including 22 parts of activated rice husk silica, 28 parts of diatomaceous earth, 9 parts of hydrogen-based bentonite, 5 parts of natural clinoptilolite, and 7 parts of humic acid; and a functional layer B including 18 parts of rice husk biochar, 11 parts of oyster shell powder, 2.5 parts of sodium lignosulfonate, 1.5 parts of polycaprolactone micropowder, and 9 parts of stearic acid-modified bentonite.

[0108] The preparation method is the same as in Example 1, except that the target bacterial load is a composite agent of nitrifying and denitrifying bacteria. The finished product has a particle size of 3.2 mm, is air-dried at 30°C for 4 hours, and the survival rate of live bacteria reaches 89%.

[0109] Performance tests showed that when aquaculture water with an ammonia nitrogen concentration of 1.2 ppm was introduced, the ammonia nitrogen concentration dropped to 0.1 ppm and the nitrite concentration dropped to 0.02 ppm after 7 days. The pH of the water stabilized at 7.0-7.5, and the survival rate of farmed fish increased by 20%. When used for wastewater treatment in constructed wetlands, the removal rate of total nitrogen in domestic sewage reached 81%, and the removal rate of total phosphorus reached 74%.

[0110] Industrial applicability

[0111] The integrated fertile soil granules of this invention are made from agricultural waste and natural minerals such as rice husk silica, diatomaceous earth, and oyster shell powder. The raw materials are widely available and inexpensive. The preparation process uses conventional extrusion, spheroidization, and drying equipment, without the need for special customized equipment. It can be directly connected to existing fertilizer granulation production lines to achieve large-scale continuous production. The capacity of a single production line can reach 500 tons / day.

[0112] The product's functions cover multiple fields such as agricultural soil improvement, aquaculture water purification, urban ring water system management, and artificial wetland wastewater treatment. It can not only meet the needs of "pesticide-free cultivation and soil regeneration" in farmland, but also adapt to the ecological restoration of extremely acidic and alkaline soils and various water bodies. In particular, it has the ability to deliver deep roots and the technology to ensure the loading of live bacteria. It can be applied to the root soil improvement of fruit trees and other cash crops through deep tillage machines, and has extremely high industrial practicality and market promotion value.

Claims

1. A type of indigenous bacteria activation-soil improvement integrated soil core regeneration granule, characterized in that, The particles adopt an A / B two-component layered structure, consisting of a disintegration triggering core, an A-component habitat layer, and a B-component functional layer from the inside out. The disintegration triggering core, by weight, comprises 3-5 parts of citric acid microcapsules, 2-3 parts of sodium bicarbonate, and 4-6 parts of hydroxypropyl methylcellulose; the citric acid microcapsules use gelatin-gum arabic as the composite wall material, have a particle size of 10-20 μm, an encapsulation rate of ≥80%, and a citric acid release of ≤10% within 11 months in a soil environment, and a release of ≥85% after 12 months; The habitat layer of component A, by weight, includes 20-25 parts activated rice husk silica, 25-30 parts diatomaceous earth, 8-10 parts hydrogen-based bentonite, 4-6 parts natural clinoptilolite, and 5-8 parts humic acid. The habitat layer of component A forms a gradient porous structure with pore sizes concentrated in the range of 0.5-2 μm and a pore connectivity rate of ≥80%. Furthermore, the components synergistically inhibit pore blockage caused by the secretion of mucopolysaccharides from the bacterial community. The functional layer of component B, by weight, includes 15-20 parts of rice husk biochar, 10-12 parts of oyster shell powder, 2-3 parts of sodium lignosulfonate, 1-2 parts of polycaprolactone micro powder, and 8-10 parts of stearic acid-modified bentonite. The rice husk biochar and humic acid synergistically provide long-lasting carbon source nutrition. The overall pH buffer range of the particles is 6.0-8.0, which can resist the impact of acid rain and soil over-alkalization. The CO2 gas generated by the reaction of the citric acid microcapsules with sodium bicarbonate can actively push the bacteria and nutrients enriched in the particles to the deeper soil layers within a range of 5-8 cm.

2. The integrated fertile soil particles according to claim 1, characterized in that, The gradient porous structure of the habitat layer of component A includes 0.5-1 μm bacterial colonization pores and 1-2 μm fungal spore colonization pores, and interconnected channels are formed between the pores. Combined with the ion exchange properties of hydrogen-based bentonite, it reduces the adsorption and deposition of mucopolysaccharides on the pore walls.

3. The integrated fertile soil particles according to claim 1, characterized in that, The rice husk biochar in the functional layer of component B has a specific surface area ≥300m² / g, which together with humic acid constitutes a long-term nutrient supply system for microorganisms, providing carbon, nitrogen, phosphorus, potassium and trace elements to meet the nutritional needs of the microbial community throughout its colonization, reproduction and diffusion cycle; the polycaprolactone micropowder has a molecular weight of 8000-10000, which, together with citric acid microcapsules, enables the particles to precisely disintegrate in the soil within 12 months.

4. The integrated fertile soil particles according to claim 1, characterized in that, The particles also include a targeted microbial community transplantation function. The functional microbial agent loaded on the surface of the B component functional layer is a compound microbial agent of one or more of the following: phosphate-solubilizing bacteria, Bacillus subtilis, and denitrifying bacteria. The microbial community loading is carried out after low-temperature heat treatment and cooling of the particles to room temperature to ensure the biological activity of the microbial community. The loaded targeted functional bacteria can directionally enhance the water body's ability to remove nitrogen and phosphorus and degrade organic matter.

5. A method for preparing the integrated fertile soil particles according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Preparation of citric acid microcapsules: ① Weigh 5g each of gelatin and gum arabic, add them to two beakers containing 100mL of deionized water, stir at 50℃ for 30min until completely dissolved, and mix to obtain a 5% concentration gelatin-gum arabic composite wall material solution. ② Weigh 10g of 200-mesh citric acid powder and add it to the wall material solution. Shear emulsify at 8000-10000rpm for 15min, then add 1mL of glycerol and stir for 10min. ③ Keep at 50℃, adjust the pH of the system to 4.0-4.2 with 10% hydrochloric acid, stir at constant temperature for 30 minutes to form blastocysts, cool naturally to 25℃, then cool in an ice water bath to below 5℃ and keep warm for 30 minutes; ④ Add 2 mL of 25% glutaraldehyde solution dropwise under stirring in an ice-water bath, crosslink for 60 min, wash with deionized water and anhydrous ethanol in sequence, vacuum dry at 40℃ for 8 h, and obtain citric acid microcapsules by 200 mesh sieve. (2) Preparation of disintegration triggering core: The citric acid microcapsules, sodium bicarbonate and hydroxypropyl methylcellulose obtained in step (1) are mixed evenly and extruded into small particles with a diameter of 1 mm using a screw extruder. They are dried at 40°C for 2 hours and set aside for later use. (3) Preparation of habitat layer slurry of component A: Dry mix activated rice husk silica, diatomaceous earth, hydrogen-based bentonite, natural clinoptilolite and humic acid for 10 min, add sodium alginate solution with a concentration of 1.5%-2% to make a viscous slurry, and construct a 0.5-2μm gradient porous structure by means of raw material particle size distribution; (4) A component coating granulation: The trigger core particles from step (2) are fed into a spheroidizer, the rotation speed is set to 30-40 r / min, the A component slurry from step (3) is sprayed and coated, spheroidized to a particle size of 2.5 mm, transferred to a 2% calcium chloride solution for crosslinking for 30 min, and dried at 60℃ for 4 h to obtain intermediate particles. (5) Preparation of functional layer coating powder of component B: Dry mix rice husk biochar, oyster shell powder and sodium lignosulfonate for 10 min, then add polycaprolactone micro powder and stearic acid modified bentonite, and continue mixing for 15 min to make uniform coating powder. (6) Component B coating granulation: The intermediate particles are placed in a spheroidizing machine, and a 1%-2% sodium alginate binder is sprayed on. Component B coating powder is sprinkled on simultaneously. The particles are spheroidized to a particle size of 3-3.5 mm and dried at 70°C for 3 hours to obtain the initial finished product particles after coating. (7) Low temperature heat treatment: The initial finished particles from step (6) are placed in a box-type resistance furnace and heated to 200-350℃ at a heating rate of 5℃ / min, kept at the temperature for 2 hours, and then naturally cooled to room temperature. This low temperature heat treatment process is a structural strengthening step, not a drying step, and the properties of the gelatin-arabic capsule wall and core material of the citric acid microcapsules are stable at this temperature. (8) Targeted microbial loading (optional): Immerse or spray the finished product particles after cooling in step (7) into the functional bacterial solution, let stand for 2 hours, take them out and air dry at room temperature for 4-6 hours in a dark and ventilated environment at 25-30℃ to complete the microbial loading.

6. The preparation method according to claim 5, characterized in that, The role of the low-temperature heat treatment process in step (7) is to strengthen the interfacial bonding strength of components A and B, stabilize the gradient porous structure, avoid pore collapse, and at the same time not damage the sustained-release performance and active nutrients of the citric acid microcapsules. This temperature will cause the microbial community to become inactive, so the targeted microbial community loading step needs to be carried out after heat treatment and cooling.

7. The preparation method according to claim 5, characterized in that, The drying in steps (4) and (6) is a segmented drying process, which is carried out after the coating of component A and component B, respectively. The purpose is to remove the moisture introduced during the coating process and ensure the stability of the structure of each layer. The low-temperature heat treatment in step (7) is independent of the drying step, and the two are not interchangeable.

8. The application of the integrated fertile soil particles according to any one of claims 1-4, characterized in that, The granules are used for disease control and soil regeneration in ordinary farmland, and for improving special soils such as severely saline-alkali land and acidified soil. They can also be extended to aquaculture water purification, urban ring water system water purification, and artificial wetland sewage treatment. The single application rate is 20-30g / kg soil. The application methods include surface spreading, topsoil mixing, and targeted delivery to the root system of trees using deep tillage equipment. It can achieve synergistic effects of saline-alkali soil improvement, activation of native beneficial bacteria, and soil structure reconstruction. It is especially suitable for targeted root improvement of fruit trees and other cash crops. It can be delivered to the root soil layer at a depth of 50-80cm by deep tillage machines and can play a stable role in acidic soil, alkaline soil, and soil affected by acid rain. In water purification scenarios, the dosage is 10-50g / m³ water body, which can achieve ammonia nitrogen and total phosphorus removal rates of ≥80% and ≥70%, respectively.

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