A granular fertilizer for improving saline-alkali soil based on traditional Chinese medicine active substance cooperation and multi-stage endogenous controlled release and a preparation method thereof

Abstract

The application discloses a granular fertilizer for improving saline-alkali soil based on traditional Chinese medicine active matter cooperation and multi-stage endogenous controlled release, and a preparation method and application thereof. Fermented straw is used as a core organic carrier, and milk and a traditional Chinese medicine (Astragalus, licorice, honeysuckle and the like) active matter collection rich in amino acids and proteins are introduced innovatively in the fermentation process, so that the quality and biological activity of the carrier are improved significantly. The carrier can not only be dissolved quickly to create a high-activity microenvironment for functional microorganisms, but also cooperates with the traditional Chinese medicine active matter to build a whole-chain ecological restoration network covering soil chemical improvement, biological cycle acceleration, plant stress resistance induction and soil-borne disease prevention. In combination with a four-fold endogenous protection system of microorganisms, an internal intercommunication porous structure formed by low-temperature compression and quantitative regulation of the coating thickness, the functional bacterial population has an ultrahigh survival rate, the saline-alkali and biological obstacles are improved synchronously, and the nutrient intelligent release is realized.

Description

Technical Field

[0001] This invention belongs to the field of agricultural resources and environmental technology, specifically relating to a compound functional fertilizer for improving saline-alkali land, and more particularly to a granular fertilizer for improving saline-alkali land based on the synergistic effect of active ingredients of traditional Chinese medicine and multi-level endogenous controlled release, as well as its preparation method and application. Background Technology

[0002] Globally, saline-alkali land is a significant obstacle to agricultural production and ecological security. Current saline-alkali land improvement technologies face the following bottlenecks: First, traditional chemical amendments (such as gypsum) have limited functions, and long-term use easily leads to soil compaction, failing to simultaneously provide crops with the necessary nutrients and biological activity. Second, while existing bio-organic fertilizers or microbial agents can improve soil microecology, their functional microorganisms are easily deactivated during fertilizer processing (especially high-temperature granulation and drying) and long-term storage, resulting in short product shelf life and unstable field effects—a common problem in the industry. Third, conventional organic carriers have limited functions, primarily serving as physical support and slow-release carbon sources, offering limited assistance to microorganisms in the initial establishment process under saline-alkali stress. Fourth, the physical structure design of fertilizers is often crude, leading to uncontrollable release behavior.

[0003] In recent years, the potential of biofertilizers in improving soil quality has received widespread attention. Research in related fields shows that, in agricultural production systems, the scientific application of fertilizers rich in functional microorganisms can significantly activate soil nutrient pools, substantially increasing the content of available phosphorus, available nitrogen, and readily available potassium. Simultaneously, continuous application can effectively increase the organic matter content of the topsoil, improve soil aggregate structure, enrich microbial diversity, and provide a biological pathway to improve the comprehensive utilization rate of nutrients such as nitrogen, phosphorus, and potassium. However, ensuring that these functional microorganisms maintain high activity in harsh saline-alkali environments and after fertilizer processing and storage, and achieving rapid activation and long-term maintenance of their soil-improving functions, remains a bottleneck that current technology has not yet systematically resolved.

[0004] In existing technologies, conventional compound fertilizer granulation processes generally employ high-temperature (typically >80℃) drying techniques. This process kills a large number of temperature-sensitive functional microorganisms, leading to the loss of the core biological functions of such "bio-chemical" compound fertilizers. This invention addresses this technical bottleneck by innovatively employing a full-process low-temperature (≤45℃) pressing and drying process. Experimental verification shows that this process effectively protects the activity of core functional microorganisms such as Bacillus licheniformis and Bacillus subtilis, exhibiting extremely low heat damage rates below 65℃ (e.g., ≤2.69%). This ensures that the microorganisms enter the soil in a highly active state, laying an irreplaceable biological foundation for the fertilizer's rapid and long-lasting effects.

[0005] Furthermore, while existing saline-alkali land management engineering measures (such as laying impermeable membranes to isolate salt and installing underground drainage pipes to leach salt) can control salinity for a certain period, they often fail to actively eliminate existing salt damage in the topsoil, are difficult to simultaneously improve soil fertility, and may lead to secondary problems such as soil structure damage or nutrient loss. Therefore, developing a biological improvement product that can work efficiently with these engineering measures to achieve an integrated function of "salt inhibition / drainage + active salt reduction + ecological fertilization" is of great significance for improving the comprehensive benefits and sustainability of saline-alkali land management.

[0006] Therefore, developing a special fertilizer for saline-alkali land that can systematically solve the four core problems of "long-term maintenance of microbial activity", "efficient colonization of microbial communities", "intelligent release of nutrients / microbial communities" and "predictable and controllable release performance" is of great significance for achieving efficient, precise and sustainable management of saline-alkali land. Summary of the Invention

[0007] (I) Purpose of the Invention

[0008] This invention aims to overcome the aforementioned shortcomings of existing technologies and provide a granular fertilizer for the systematic improvement of saline-alkali land based on the synergistic effect of active ingredients from traditional Chinese medicine and multi-level endogenous controlled release, as well as its preparation method. The primary objective of this invention is to construct a highly efficient microbial endogenous protection system. The second objective is to achieve optimization of the fertilizer's physical structure and rapid initiation. The third objective is to achieve precise design and control of release performance. The fourth objective is to expand and deepen the fertilizer's function in activating plant systemic resistance and ecological disease suppression by introducing specific active ingredients from traditional Chinese medicine.

[0009] (II) Technical Solution

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A granular fertilizer for improving saline-alkali land based on the synergistic effect of active ingredients from traditional Chinese medicine and multi-level endogenous controlled release, has the following formula by mass percentage: 45%-50% fermented organic carrier; 6%-8% fulvic acid or potassium humate; 6%-7% gypsum; 0.8%-1.0% sulfur powder; 9%-10% superphosphate; 1.5%-2.0% urea; 1.2%-1.5% potassium chloride; 2.5%-3.0% ferrous sulfate; 2%-3% seaweed extract; 5% aggregate of active ingredients from traditional Chinese medicine; 1.9%-2.7% compound microbial agents and compound biological enzymes; 4.0%-5.2% binder and coating agent; the sum of the mass percentages of the above components is 100%.

[0012] The fermentation organic carrier is preferably agricultural waste such as chili stalks and cotton stalks, prepared through a specific fermentation process, with an organic matter content ≥30% and a germination index ≥85%. As an optional optimization measure, 5%-10% of its dry weight of milk or whey can be added during the fermentation process to further improve the composting quality and the water-soluble organic matter content in the carrier.

[0013] The aforementioned aggregate of active traditional Chinese medicine substances is a combination of active substances rich in various amino acids and proteins, derived from traditional Chinese herbs such as Astragalus membranaceus, Glycyrrhiza uralensis, and Lonicera japonica. Preferably, it is added together with milk and participates in fermentation during the preparation stage of the fermentation organic carrier, thereby deeply integrating its functions into the carrier.

[0014] The compound microbial agent includes enzyme-producing bacteria, Bacillus mucilaginosus, halophilic bacteria, and Trichoderma; the compound bioenzyme is cellulase and protease.

[0015] The adhesive coating agent includes bentonite (3%-4%) and chitosan-humic acid composite coating agent (1.0%-1.2%).

[0016] The present invention also provides a method for preparing the above-mentioned granular fertilizer, characterized by comprising the following steps:

[0017] 1. Fermentation and composting of organic carrier: Crush the organic carrier raw material to 20-40 mesh, add 0.5% urea by weight to adjust the carbon-nitrogen ratio to 25-30, inoculate with 0.3% enzyme agent by weight, and add milk or whey equivalent to 5%-10% of the dry weight of the organic carrier, and a collection of active Chinese medicine substances equivalent to 5% of the dry weight of the organic carrier. Adjust the moisture content to 55%-60%, carry out aerobic fermentation until the germination index of the material is ≥85%, and dry and cool for later use.

[0018] 2. Sequential mixing and microbial agent protection: First, mix the fermentation organic carrier with superphosphate, gypsum, sulfur powder, ferrous sulfate, potassium chloride, and bentonite; Second, add humic acid or potassium humate and seaweed extract and mix; Third, dilute the compound microbial agent and biological enzymes with part of the fermentation organic carrier and add them to the mixture under the conditions of material temperature ≤35℃ and low-speed stirring.

[0019] 3. Low-temperature pressing and structure formation: After the mixture is conditioned, it is granulated at room temperature using a roller extruder (particle size 3-5mm), and then dried in a three-stage gradient at a temperature not exceeding 60℃ (45-50℃→55-60℃→40-45℃) and cooled to make the particle moisture content ≤8%.

[0020] 4. Coating and performance control: The particles are coated with chitosan-humic acid composite coating solution. By controlling parameters such as coating solution concentration and spray volume, the coating weight gain is controlled within 1.0%-1.2%, and the coating layer thickness is controlled within the range of 70-140μm to achieve the predetermined disintegration and release performance. Then, the particles are screened and packaged.

[0021] To achieve rapid response and disintegration of the coating in soil, this invention preferentially uses readily biodegradable natural polymer materials such as sodium alginate and modified starch as the coating matrix. By controlling the composition of the coating solution and the spraying process, the coating layer thickness can be precisely controlled between 71.3 μm and 135.6 μm, forming a coating layer with a porous or layered structure. This design ensures that the granular fertilizer can rapidly disintegrate within 24 to 72 hours under suitable soil moisture conditions, thereby achieving rapid nutrient release and rapid colonization of microorganisms. Simultaneously, the porous structure inside the granules provides a protective microenvironment for the microorganisms, further synergistically enhancing the overall performance of the product.

[0022] The present invention also claims protection for the use of the granular fertilizer in the improvement of saline-alkali soils with pH ≥ 8.5 and / or EC ≥ 4 ms / cm.

[0023] (III) Core Innovation, Creativity and Practicality

[0024] The technical solution of this invention transcends the simple approach of "material compounding" in existing saline-alkali land improvement technologies, creatively constructing a dynamic ecosystem engineering based on the deep interaction of specific functional components and precise regulation of multi-level structures. Its core innovation is not the discovery of a single component, but rather the systematic integration and functional coupling of four key elements: specific bioactive substances derived from traditional Chinese medicine (a collection of active substances from traditional Chinese medicine), highly active functional microbial communities, fermentation-optimized organic carriers, and multi-level physical controlled-release structures, through a complete low-temperature process chain. This results in a synergistic gain effect of "1+1+1+1>4".

[0025] In terms of inventiveness, this invention achieves fundamental breakthroughs on three levels:

[0026] 1. Breakthrough in principle: The "Chinese herbal active ingredients - functional microbial community - organic carrier" fermentation synergistic effect mechanism was proposed and practiced for the first time, transforming Chinese herbal active ingredients from exogenous additives into participants and regulators in the fermentation process, enabling their functions to be deeply integrated and enhanced through biotransformation.

[0027] 2. Structural Breakthrough: A unique multi-level controlled-release physical structure of "internal porous framework + controllable coating" has been developed. The internal interconnected porous structure formed by low-temperature pressing ensures "rapid start-up", while the quantitatively designed coating layer achieves "long-lasting sustained release". The combination of the two precisely solves the contradictory needs of "rapid effect and long-term maintenance" in saline-alkali land improvement.

[0028] 3. Systemic Breakthrough: The previously isolated mechanisms of action, such as "chemical passivation (gypsum, etc.), biological activation (bacteria and enzymes), physical conditioning (porous and coated), and plant stress resistance induction (active substances of traditional Chinese medicine)," are integrated into an orderly relay and mutually reinforcing "soil-microbe-plant" systemic remediation network, achieving a systematic leap from improving the soil environment to activating the plant's own stress resistance.

[0029] In terms of practicality, the technical solution of this invention has outstanding industrial implementation value and application prospects:

[0030] 1. Feasible process: All preparation steps (fermentation, low-temperature granulation, coating) are optimized based on existing mature equipment and process parameters, without harsh conditions, and are suitable for large-scale stable production.

[0031] 2. Verifiable effects: The product has clear and detectable indicators (microbial survival rate, coating thickness, disintegration time, nutrient release curve) and quantifiable field effects (yield increase rate, fertilizer reduction rate, soil improvement data), and the effects are stable and reliable.

[0032] 3. Precise matching of needs: The product directly targets the complex obstacles of "salt, alkali, stagnation, poor soil and disease" in saline-alkali land, providing an integrated solution with multiple functions such as improvement, nutrition, biological control and growth promotion. It has a clear market positioning and significant application value.

[0033] In summary, the technical solution provided by this invention is not obvious to those skilled in the art, and its comprehensive technical effects far exceed the simple summation of existing technologies, possessing outstanding substantive characteristics. Furthermore, this solution can be manufactured using industrial methods and solves the long-standing systemic problem of saline-alkali land improvement, generating positive agricultural and ecological benefits and demonstrating significant progress. Therefore, this invention fully complies with the provisions of patent law regarding inventiveness and industrial applicability.

[0034] (iv) Mechanism of action

[0035] The underlying scientific principle of this invention lies in constructing a synergistic biochemical remediation network with "multi-level response and functional relay," rather than merely a physical mixing of components. This network drives the systemic remediation of saline-alkali soils through the sequential and synergistic operation of four key mechanisms:

[0036] 1. Biphasic Release and Chemical Environment Remodeling Mechanism of Organic Acids: The water-soluble organic acids pre-stored in the fermentation organic carrier constitute the "initiation phase," which is rapidly released after application, quickly neutralizing alkalinity and chelating salt ions, creating a favorable microenvironment for subsequent biological processes. After colonization, functional microbial communities (such as Bacillus mucilaginosus) continuously secrete metabolic organic acids, forming the "maintenance phase." This not only continuously activates soil-bound nutrients but also establishes a rhizosphere acidic microzone that constitutes a dynamic chemical and biological barrier to inhibit salt uptake.

[0037] 2. Enzyme-Bacterial Symbiosis-Driven Accelerated Mechanism of Material and Energy Cycle: Exogenously added complex biological enzymes (cellulase, protease) form a highly efficient symbiotic relationship with functional microbial communities. Enzymes, as "pioneers of biocatalysis," rapidly decompose organic matter, providing readily available substrates for microbial proliferation. The vigorous metabolism of microorganisms, in turn, secretes a richer enzyme system, forming a "self-reinforcing positive feedback loop," thereby exponentially accelerating the transformation of soil organic matter, nutrient release, and humus formation, providing the core driving force for soil structure improvement and soil fertility enhancement.

[0038] 3. Biosignal-mediated plant-microbe synergistic adaptation mechanism: Functional microbial communities are not only executors of soil improvement but also regulators of plant physiology. The plant hormone-like substances (such as auxins) and specific signaling molecules (such as volatile organic compounds) they secrete can directly "communicate" with crop roots, systematically regulating the balance of endogenous hormones in plants, inducing optimized root architecture, and initiating stress-resistance metabolic pathways. This achieves a fundamental shift from passive "soil treatment" to active "crop-soil-microbe" tripartite synergistic adaptation and performance enhancement.

[0039] 4. The "soil-plant" system regulation and health management mechanism of synergistic active ingredients of traditional Chinese medicine: The collection of active ingredients of traditional Chinese medicine introduced in this invention (rich in amino acids and proteins, derived from Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, etc.) is not a simple additive, but rather a "bioactive and signaling hub" that drives system improvement by undergoing deep biochemical interactions with organic carriers and functional microbial communities through fermentation.

[0040] Enhanced microbial metabolism and function: The abundant amino acids and proteins it provides serve as high-quality nitrogen sources and metabolic precursors, which can be efficiently utilized by functional bacterial communities (such as Bacillus mucilaginosus and Trichoderma), promoting their proliferation and enhancing their metabolic activity. This, in turn, synergistically strengthens functions such as organic acid secretion (aiding in soil improvement), antibiotic production (aiding in disease prevention), and synthesis of growth-promoting substances (aiding in growth promotion).

[0041] Activating Plant Systemic Resistance via Multiple Pathways: Specific active ingredients from sources such as Astragalus membranaceus, Glycyrrhiza uralensis, and Lonicera japonica possess known biostimulatory and immunomodulatory effects. As exogenous elicitors, they synergistically work with endogenous signaling molecules (such as hormones and polysaccharides) secreted by functional microbiota to activate plant systemic resistance (SAR / ISR) through multiple physiological pathways, significantly enhancing crop physiological tolerance, root vigor, and overall growth potential under saline-alkali stress.

[0042] Constructing a disease-suppressing soil microecology: During fermentation and soil colonization, this aggregate and its metabolites help to selectively promote the colonization and dominance of beneficial bacteria (such as Trichoderma), while some of its components have a direct inhibitory effect on soil-borne pathogens, thereby constructing a healthy, balanced microecological system with biological buffering capacity in the rhizosphere and achieving ecological disease suppression.

[0043] This mechanism signifies that the core technology of this invention has been upgraded from focusing on external environmental modification to a systemic ecological engineering strategy that addresses both the symptoms and root causes. This strategy involves activating and connecting the "soil microbial network" and the "plant physiological network" from within by introducing specific bioactive substances from the outside, thereby achieving sustainable soil health and plant stress resistance management.

[0044] (V) Beneficial Effects

[0045] Compared with the prior art, the present invention has the following outstanding advantages and inventiveness:

[0046] 1. A four-fold synergistic microbial endogenous protection system was constructed, achieving a breakthrough in microbial community survival rate. This invention innovatively integrates formulation components with process technology, forming a four-in-one protection network encompassing physical, chemical, biological, and technological aspects:

[0047] Physical buffering and habitat carrier: A high proportion of porous fermentation organic carrier and bentonite provide physical space and attachment points for microorganisms. Specifically, the fermentation organic carrier of this invention can naturally produce or enrich water-soluble small-molecule organic matter (such as sugars and organic acids) during the composting process by adding nutrients such as milk. When fertilizer is applied to the soil and decomposes upon contact with water, these components dissolve rapidly, forming a highly active organic microenvironment around the particles, effectively buffering salt and alkali stress, providing a crucial "initial protective liquid" for functional microorganisms, and significantly improving their colonization success rate. This invention further provides the introduction of milk (or whey) during straw fermentation as an effective optimization method, creating a high-performance carrier that combines physical support and physiological conservation functions. The addition of milk provides fermentation microorganisms with high-quality, fast-acting nutrients such as lactose and milk protein, significantly accelerating the fermentation process, increasing the composting degree to a germination index ≥95%, and greatly increasing the content of water-soluble organic matter in the carrier. This allows the carrier to be rapidly released in the soil and form a microenvironment rich in active substances, which is like providing a highly efficient "start-up protective liquid" for functional microorganisms, realizing the functional leap of the carrier from "physical support" to "physiological activation".

[0048] Bionic vitrification dehydration protection: Fulvic acid / potassium humate and small molecule organic matter produced by fermentation can form a "glassy" protective layer similar to trehalose on the surface of bacterial cells during low-temperature drying, stabilizing their biomolecular structure and resisting dehydration damage.

[0049] Nutrition and stress-inducing environment: Algae extract and abundant organic matter provide nutrition and stress-inducing signals for microbial recovery; the rational combination of functional strains can mutually induce and enhance stress tolerance.

[0050] Process and coating for ultimate protection: "Sequential mixing" avoids direct damage from the bacterial agent and the high-salt environment; "low-temperature gradient drying at ≤60℃" achieves gentle dehydration; and the final "chitosan-humic acid coating" forms a physical barrier against oxygen and moisture.

[0051] This system has undergone rigorous testing, which has increased the survival rate of core functional bacteria by tens to hundreds of times compared to conventional technologies after 18 months of storage, completely solving the industry pain point of maintaining the activity of bio-fertilizers.

[0052] 2. A controllable release system with a porous structure based on cryogenic pressing was established, enabling rapid activation of the improved effect. This invention reveals for the first time the active regulatory effect of cryogenic rolling granulation process on the core physical structure and release behavior of particles:

[0053] Active construction of porous structure: Unlike the melt densification of high-temperature pelleting, the low-temperature process of ≤60℃ preserves the straw fiber skeleton and actively forms an interconnected micron-scale pore network inside the pellet under mechanical extrusion and gentle dehydration.

[0054] Rapid disintegration and instantaneous start-up: The porous structure endows the particles with super hydrophilicity, causing them to completely disintegrate in still water within an average of 25 minutes, realizing the instantaneous release of functional microbial communities and fast-acting nutrients, meeting the urgent need for "rapid start-up" in saline-alkali land improvement.

[0055] 3. A precise design method for release performance based on quantitative regulation of coating structure was established, enabling predictable and customizable long-term maintenance. This invention transcends the conventional approach of achieving slow release through simple coating, and for the first time establishes and applies a quantitative regulation model between "coating structure parameters, material mechanical properties, and nutrient release kinetics" in this fertilizer system:

[0056] Precise control of thickness and performance: By controlling the coating process, the coating layer thickness can be stably controlled within a precise range of 70-140 μm. The coating thickness is positively correlated with disintegration time and nutrient release rate, serving as a direct lever for performance control.

[0057] Mechanical performance-oriented intelligent design: The elastic modulus of the coating layer is strongly negatively correlated with the nutrient release rate, while the elongation at break is strongly positively correlated with it. By adjusting the coating material formulation, the release behavior can be precisely controlled.

[0058] Predictable and customizable release behavior: Based on the above quantitative relationship, "on-demand design" of product release performance can be achieved. For example, different sustained release rates of phosphorus, ranging from approximately 59.5% to 72.5%, can be achieved within 72 hours to match the needs of different improvement stages.

[0059] 4. This invention reveals the deep biochemical network driving the systematic restoration of saline-alkali land, representing a groundbreaking breakthrough in principle. This invention is not a simple aggregation of existing technologies; its core innovation lies in revealing and applying a synergistic network composed of "chemical initiation-biological cycle-signal regulation":

[0060] At the chemical level, a dual-phase organic acid relay mode of "carrier pre-stored acid for rapid start-up and microbial metabolic acid for long-term maintenance" was pioneered, realizing a seamless connection from instantaneous environmental improvement to continuous biological salt control.

[0061] At the biological level, a symbiotic cycle of "exogenous enzyme catalysis of cell wall breaking and functional bacterial metabolic transformation" has been constructed, which improves the efficiency of organic matter decomposition and nutrient release to a level that is difficult to achieve with traditional technologies, providing a continuous flow of materials and energy for the reconstruction of soil ecosystems.

[0062] At the system level, the concept of "microbial signal-mediated plant physiological programming" was introduced. Functional microbial communities actively guide crops to optimize their growth strategies (such as developing a strong root system) under salt and alkali stress by secreting biostimulants, thereby expanding the target of improvement from a single "soil" to a "soil-crop" symbiotic system and achieving endogenous enhancement of stress resistance.

[0063] This multi-layered, networked mechanism transforms the improvement process of this invention from a static "fertilization behavior" into a dynamic, self-sustaining "ecological restoration process." This is not merely a superposition of technical effects, but a leap in technical principles, constituting the prominent substantive features and significant progress of this invention.

[0064] 5. The synergistic mechanism yields significant and predictable comprehensive agronomic benefits, with broad application prospects. This invention provides not only a product technical solution, but also a virtuous cycle system capable of driving the ecological restoration of saline-alkali land. Based on the aforementioned "endogenous protection system" ensuring ultra-high microbial activity, the "porous structure" and "coating regulation" enabling precise release, and the synergistic improvement mechanism driven by a "multi-level biochemical network," this product is expected to produce comprehensive and sustainable improvement effects in field applications.

[0065] In terms of rapid soil improvement: relying on mechanisms such as "dual organic acid drive", it can efficiently neutralize alkalinity, chelate salts, and significantly activate phosphorus, potassium and other trace elements that are fixed in the soil, quickly transforming obstacle soil into arable soil.

[0066] In terms of continuous soil fertility cultivation: through the continuous transformation of organic matter through the "enzyme-bacterial symbiosis" cycle, the organic matter content of the soil can be effectively increased, the formation of aggregate structure can be promoted, the compaction can be broken, and a deep, loose and fertile growth base can be created for crop roots.

[0067] In terms of efficient nutrient utilization: Through the optimization of the rhizosphere environment by functional microbial communities and the regulation of crop physiology by their secreted biosignal molecules, the absorption and utilization efficiency of nutrients such as nitrogen, phosphorus, and potassium by crops can be synergistically improved, achieving reduced application and increased efficiency.

[0068] In terms of ecosystem reconstruction: the successful colonization of highly active functional microbial communities will help optimize the rhizosphere microbiome, enhance soil biodiversity, and thus build a more resilient and productive soil micro-ecosystem.

[0069] Therefore, this invention addresses the core pain point of "bacteria failing to survive and effects not being achieved," ultimately aiming to achieve the comprehensive goals of "reduced salinity, increased soil fertility, high fertilizer efficiency, and improved ecology," providing a complete solution that is both innovative and practical for the large-scale, sustainable management and agricultural utilization of saline-alkali land.

[0070] 6. The innovative introduction of a complex of active Chinese medicinal herbs from specific sources has enabled a diversified and systematic upgrade of the saline-alkali land improvement function.

[0071] Carrier fermentation enhancement: As a fermentation enhancer rich in amino acids and proteins, it significantly improves the fermentation efficiency and quality of organic carriers, resulting in higher content of bioactive substances.

[0072] Endogenous activation of plant stress resistance: The active ingredients of traditional Chinese medicines such as astragalus, licorice, and honeysuckle work synergistically with functional microbial communities to establish a powerful plant immune induction signaling network, thereby enhancing the crop's salt and alkali tolerance and stress resistance from the root.

[0073] Integrated soil health management: While efficiently improving the physical and chemical barriers of saline-alkali soil, ecological disease-suppressing factors are introduced simultaneously to prevent soil-borne diseases, achieving a dual rejuvenation of the soil's physical, chemical, and biological properties.

[0074] Compared with existing technologies, the microbial-containing low-temperature pressed coated granular fertilizer provided by this invention has the following significant beneficial effects:

[0075] 1. Excellent preservation of biological activity: The low-temperature process throughout the entire process fundamentally solves the problem of inactivation of functional bacteria during fertilizer production, ensuring that highly active bacteria reach the soil directly.

[0076] 2. Rapid nutrient release: The specific biodegradable coating material and structural design enable the fertilizer to disintegrate rapidly (24-72 hours) according to agricultural needs, meeting the rapid nutrient requirements of crops during critical growth periods.

[0077] 3. Significant nutrient utilization and growth-promoting effects: After the core functional microbial community (such as Bacillus subtilis) regains its activity in the soil, it effectively activates fixed nutrients such as phosphorus and potassium in the soil by secreting metabolic products such as organic acids and phosphatases. According to experimental data, phosphorus utilization efficiency can be increased by 27%-32%. At the same time, the plant hormones produced by the microbial community can stimulate root development, forming a virtuous cycle of "promoting growth through microbial activity and promoting absorption through growth".

[0078] 4. High comprehensive agronomic and environmental benefits: Field application results show that, while reducing the use of conventional chemical fertilizers by 20%-30%, the product of this invention can still achieve yield increases of 11%-43% for various crops such as wheat, rice, and vegetables. Long-term application can also improve soil aggregate structure and increase soil organic matter content by 15%-20%, thus having the dual effects of increasing yield and nourishing the soil.

[0079] 5. This invention can also complement existing saline-alkali land engineering treatment technologies (such as isolation and anti-salinization technology and drainage and salt washing technology).

[0080] For physically isolated plots, it can proactively reduce the "salt stock" in the topsoil and quickly rebuild a healthy soil ecosystem on the isolation layer, solving the pain point that engineering measures "can prevent but cannot change".

[0081] For drainage and salt-removing plots, biological modification can significantly improve soil permeability, promote the release of hidden salts, thereby greatly improving the salt-washing efficiency of the drainage system and simultaneously maintaining the soil, solving the problem of "draining but not retaining fertility".

[0082] This demonstrates the systematic advantage of this invention as a "biochemical engine" that can be embedded in different saline-alkali land management frameworks, driving its overall effect towards a more thorough and sustainable direction. Attached Figure Description

[0083] Figure 1 This is a flow chart of the preparation process of the saline-alkali land system improvement granular fertilizer described in this invention;

[0084] Figure 2 The image shows a comparison of the cross-sectional structures of the granular fertilizer prepared in Example 1 and the granules of the comparative example (high-temperature fluidized bed granulation).

[0085] a represents the particle of this invention, exhibiting abundant honeycomb-like interconnected pores;

[0086] b is a comparative example particle, showing a dense, non-porous structure.

[0087] Figure 3 This is a comparison of the nutrient (taking phosphorus as an example) release curves of the granular fertilizer of this invention and conventional compound fertilizer in a simulated soil environment;

[0088] 1. This invention (curve A):

[0089] 0-24 hours (rapid start-up period): The slope is large, and the release rate in 24 hours is close to 60%, which meets the rapid needs of crops during the critical period of fertilizer demand.

[0090] 24-168 hours (slow-release period): The slope slows down significantly, the release is stable, and it provides continuous nutrients to crops.

[0091] After 168 hours (long-lasting maintenance period): the curve flattens out, and the final release rate is over 90%, achieving long-lasting effect.

[0092] 2. Conventional compound fertilizer (Curve B):

[0093] 0-12 hours: The slope is extremely steep, and most nutrients are released rapidly in a short period of time, which can easily cause loss or seedling burn.

[0094] 24 hours later: The curve quickly enters a plateau period (release rate of about 90%), with almost no subsequent release, which cannot meet the needs of crops in the middle and late stages.

[0095] Figure 4 This is a comparison chart of the cumulative phosphorus release curves of granular fertilizers with different coating thicknesses according to the present invention. Detailed Implementation

[0096] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0097] Example 1: Preparation of granular fertilizer for systematic improvement of saline-alkali land (basic formula)

[0098] Organic carrier preparation: Chili stalks and cotton stalks are mixed in a 1:1 ratio and pulverized to 30 mesh. 0.5% urea (adjusting the C / N ratio to 28) of the straw dry weight is added, followed by 0.3% enzyme inoculant. Fresh milk (equivalent to 6% of the straw dry weight) and a complex of active traditional Chinese medicine ingredients (rich in amino acids and proteins, derived from Astragalus membranaceus, licorice, and honeysuckle) (equivalent to 5% of the straw dry weight) are also added. The moisture content is adjusted to 58%, piled into windrows, and covered with a film for aerobic fermentation. The material is heated to 60-65℃ and maintained for 72 hours, then turned over every 48 hours for a total fermentation period of 18 days. The final material is dark brown with a humus-like odor, and the germination index is 90%. The fermented material is dried to 10% moisture content and cooled to 28℃ for later use.

[0099] Sequential mixing: Take 490 kg of the above-mentioned decomposed carrier and mix it with 95 kg of superphosphate, 65 kg of gypsum, 9 kg of sulfur powder, 28 kg of ferrous sulfate, 13 kg of potassium chloride, and 35 kg of bentonite for 15 minutes. Add 70 kg of potassium humate, 25 kg of seaweed extract, and 50 kg of the active ingredient aggregate of traditional Chinese medicine, and mix for another 10 minutes. Mix 5 kg of Bacillus mucilaginosus, 5 kg of halophilic bacteria, 4 kg of Trichoderma, and 1.8 kg of compound biological enzyme with 25 kg of decomposed carrier powder (reserved in advance), dilute and mix them evenly. Add this mixture to the total mixture at a material temperature of 32℃ and low speed stirring, and mix for 8 minutes.

[0100] Granulation and Drying: The granules were moistened to 19% moisture content by spraying with a 0.5% humic acid aqueous solution. Granulation was performed at room temperature using a roller extrusion granulator, with a particle size controlled at 4mm. The wet granules were dried in three stages at 50℃ (30 minutes), 58℃ (40 minutes), and 43℃ (20 minutes), followed by cooling, resulting in a final moisture content of 7.5%. Coating: A 5% concentration chitosan-humic acid (1:3) coating solution was used for coating, controlling the coating weight gain to 1.1%. After sieving, the granules were double-sealed and stored in a cool, dry place.

[0101] Example 2: Preparation of granular fertilizer for improving saline-alkali land using milk and active ingredients from traditional Chinese medicine (optimized formula)

[0102] The only difference between this embodiment and Example 1 is the method of adding the milk and the active ingredients of traditional Chinese medicine in the preparation process of the organic carrier, in order to verify its enhancement effect:

[0103] Preparation of organic carrier fortified with milk and active ingredients of traditional Chinese medicine: The pretreatment was the same as in Example 1. After fermentation began in windrows, on the 2nd and 5th days (when turning the pile), fresh milk totaling 6% of the dry weight of the straw and a solution of active ingredients of traditional Chinese medicine equivalent to 5% of the dry weight of the straw were sprayed into the fermentation pile, and the mixture was thoroughly stirred to ensure uniform mixing with the materials. Subsequent fermentation, maturity assessment, drying and cooling processes were the same as in Example 1. The resulting carrier achieved a germination index of 95%, and its water-soluble organic carbon and amino acid content were significantly higher than those of conventional fermentation carriers.

[0104] Example 3: Application formulation adjustment for different salt and alkali types

[0105] Based on the carrier and core production process provided in Example 1 or 2, the proportion of specific components in the final product formula can be fine-tuned according to the type of saline-alkali soil in different regions to achieve a more precise improvement effect.

[0106] 1. For soda-saline-alkali soil (high pH) areas: Increase the amount of gypsum to 8% and sulfur powder to 1.2% in the basic formula. This adjustment aims to utilize the rapid organic microenvironment provided by the enhanced carrier to more efficiently activate and exert the displacement effect of calcium ions (from gypsum) on sodium ions, and the slow acidification and pH reduction effect of sulfur powder, thereby improving highly alkaline soil more quickly and effectively.

[0107] 2. For coastal areas with chloride-saline soils: In addition to the basic formula, the proportion of potassium humate should be appropriately increased to 8%. This adjustment aims to enhance the chelating and adsorption capacity of potassium humate for harmful salts such as chloride ions (Cl-), and, together with the active microenvironment formed by the disintegration and release of fermented organic carriers, synergistically reduce the concentration of chloride ions in the soil solution, thereby mitigating its salt damage to crops.

[0108] Example 4: Combined application of the granular fertilizer of the present invention with different saline-alkali land engineering treatment technologies

[0109] The granular fertilizer of this invention can not only be used alone for the improvement of saline-alkali land, but also perfectly complement existing physical / engineering treatment technologies, exerting a synergistic effect of "1+1>2" and solving the remaining problems after engineering measures.

[0110] Application Scenario 1: Combined with "isolation and anti-salinization technology" (such as laying HDPE geomembrane). For plots where deep-layer impermeable materials (such as HDPE geomembrane) have been used to physically isolate the topsoil from the high-salinity core layer, although this technology effectively prevents the vertical upward movement of salt, the residual salt in the topsoil will still continue to harm plant roots, and the soil ecosystem above the isolation layer is fragile. Applying the granular fertilizer of this invention to such plots can achieve the following:

[0111] Targeted salt reduction: The organic acids and small molecule active substances produced by the functional microbial community (such as halophilic bacteria and Bacillus mucilaginosus) in granular fertilizer can efficiently chelate and transform harmful salts such as residual sodium ions in the tillage layer, converting them into forms with lower toxicity to plants or promoting their downward leaching, thereby achieving the active reduction of "stored salt".

[0112] Ecological restoration: The abundant organic matter, amino acids, and active ingredients from traditional Chinese medicine provided by the fertilizer can quickly build a highly active microbial community and stable organic-inorganic aggregates in the limited soil space above the isolation layer. This not only improves the soil structure that may be damaged by engineering construction, but also significantly enhances the basic soil fertility and biological buffering capacity of the isolation tillage layer, transforming it from a simple "salt-free soil" into "fertile and vibrant soil".

[0113] Application Scenario 2: Used in conjunction with "drainage and salt washing technology" (such as laying permeable blind pipes).

[0114] For plots with existing underground drainage systems (such as permeable blind pipes), salt leaching efficiency is severely limited by soil permeability. Compacted or poorly structured soils hinder the migration of water and salts. Applying the granular fertilizer of this invention to such plots can achieve the following:

[0115] Enhanced efficiency: The extracellular polysaccharides and organic acids secreted by microorganisms in granular fertilizer, in synergy with humic acid, can effectively promote the aggregation of fine soil particles, increase the proportion of macropores in the soil, and significantly improve soil permeability and aeration. This effect allows natural rainfall or artificial irrigation water to carry dissolved salts downwards more quickly, greatly improving the salt removal efficiency of blind pipes.

[0116] Promotes precipitation and drainage: The unique bioactive components of this invention can act on soil colloids to promote the release of "hidden salts" that are adsorbed by soil colloids or hidden in micropores, turning them into free salts that can be leached by water, and thus completely discharged from the soil through the drainage system.

[0117] Simultaneous maintenance: While promoting salt removal, this invention continuously improves the soil after salt removal, prevents its structure from deteriorating again, and replenishes nutrients, realizing simultaneous maintenance of "salt removal, improvement and fertilization", avoiding soil depletion caused by traditional single drainage measures.

[0118] Verification Example 1: Validation of the effectiveness of a microbial endogenous protection system

[0119] The viable bacterial count of the product from Example 1 was tested after 0, 6, 12, and 18 months of storage. The results showed that after 18 months of storage, the survival rate of the core functional bacteria (Bacillus mucilaginosus and halophilic bacteria) remained above 60% of the initial value. Compared with the control group (one-time mixing and high-temperature granulation) without systematic protection, the survival rate increased by tens of times, proving the effectiveness of the endogenous protection system.

[0120] Verification Example 2: The Promoting Effect of Carrier Enhancement on Initial Microbial Colonization

[0121] Granular fertilizers prepared in Example 1 (ordinary carrier) and Example 2 (carrier enhanced with milk and traditional Chinese medicine active ingredients) were applied to the same simulated saline-alkali soil, with other conditions kept consistent. After 24 hours, soil samples were taken to detect the viable count of Bacillus subtilis. The results showed that the number of target bacteria in the soil treated with Example 2 fertilizer was significantly higher than that in Example 1. This demonstrates that adding a complex of milk and traditional Chinese medicine active ingredients during fermentation increases the water-soluble active substances and nutrient content in the carrier, thereby more effectively assisting the initial survival and colonization of functional microorganisms under saline-alkali stress, verifying the effectiveness of this optimization method.

[0122] Verification Example 3: Characterization of Particle Porous Structure and Rapid Disintegration

[0123] The particles of Example 1 were observed using a scanning electron microscope, such as... Figure 2 As shown in (a), its interior exhibits a rich honeycomb-like interconnected pore structure. According to the "Method for Determining the Disintegration of Fertilizers," the average complete disintegration time of the particles in Example 1 in still water was 25 minutes, while the comparative example (high-temperature fluidized bed granulation) particles required more than 145 minutes. This demonstrates that the porous structure formed by low-temperature pressing is key to achieving rapid disintegration.

[0124] Verification Example 4: Quantitative Control Verification of Coating Thickness on Release Performance

[0125] Two granular fertilizers with different coating thicknesses were prepared: A (coating thickness approximately 135 μm) and B (coating thickness approximately 71 μm), with the core formulation the same as in Example 1. Their cumulative phosphorus release rate in still water at 25°C for 72 hours was measured. Figure 4 As shown, the release rate of particle A is 59.5%, and the release rate of particle B is 72.5%, clearly demonstrating that the release rate can be precisely controlled by controlling the coating thickness.

[0126] Verification Example 5: Verification of the effect of a complex of active ingredients from traditional Chinese medicine on plant stress resistance and disease inhibition.

[0127] A pot experiment was conducted with three groups: CK group (applied with ordinary compound fertilizer), T1 group (applied with fertilizer from Example 1), and T2 group (applied with fertilizer from Example 2). Under saline-alkali stress, the plant height, root length, biomass, and relative electrical conductivity of leaves (membrane damage index) of crop seedlings were observed. Simultaneously, a soil-borne disease (such as damping-off) inoculation experiment was performed, and the incidence and disease index were observed. The results showed that the growth indicators of the T2 group were significantly better than those of the T1 and CK groups under saline-alkali stress, with the least membrane damage. In the disease experiment, the incidence and disease index of the T2 group were significantly lower than those of the other two groups. This verifies the synergistic effect of the active ingredients aggregate of traditional Chinese medicine in enhancing plant stress resistance and ecological disease suppression.

[0128] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Under the core concept of the present invention (formula, three major protection and release systems, and the introduction of active ingredients from traditional Chinese medicine), any equivalent transformations or improvements to the organic carrier fermentation process (such as adding milk, active ingredients from traditional Chinese medicine, molasses, and other nutrients), or minor adjustments to the proportion of coating materials, should fall within the protection scope of the present invention.

Claims

1. A granular fertilizer for systematically improving saline-alkali land based on the synergistic effect of active ingredients from traditional Chinese medicine and multi-level endogenous controlled release, characterized in that... It consists of the following components by mass percentage: Fermentation organic carrier 45%-50%; 6%-8% fulvic acid or potassium humate; 6%-7% gypsum; Sulfur powder 0.8%-1.0%; Superphosphate 9%-10%; Urea 1.5%-2.0%; Potassium chloride 1.2%-1.5%; Ferrous sulfate 2.5%-3.0%; Seaweed extract 2%-3%; 5% of the active ingredients aggregate of traditional Chinese medicine; Compound microbial agents and compound biological enzymes: 1.9%-2.7%; Adhesive coating agent 4.0%-5.2%; The sum of the mass percentages of the above components is 100%.

2. The granular fertilizer according to claim 1, characterized in that, The fermentation organic carrier is obtained by crushing chili stalks and / or cotton stalks, adjusting the carbon-nitrogen ratio, inoculating with enzyme bacteria, and fermenting and composting them. Its organic matter content is ≥30% and its germination index is ≥85%.

3. The granular fertilizer according to claim 2, characterized in that, During the preparation of the fermentation organic carrier, 5%-10% of the dry weight of milk or whey can be added to the fermentation material to improve the fermentation quality and the content of water-soluble organic matter in the carrier.

4. The granular fertilizer according to claim 1, characterized in that, The aforementioned collection of active substances from traditional Chinese medicine is a combination of active substances containing various amino acids and proteins, derived from Astragalus membranaceus, Glycyrrhiza uralensis, and Lonicera japonica.

5. The granular fertilizer according to claim 1, characterized in that, The compound microbial agent includes enzyme-producing bacteria, Bacillus mucilaginosus, halophilic bacteria, and Trichoderma; the compound biological enzyme includes cellulase and protease.

6. The granular fertilizer for improving saline-alkali land according to claim 1, characterized in that, The adhesive coating agent comprises 3%-4% bentonite by the total mass of the particles, and 1.0%-1.2% chitosan and humic acid composite coating agent by the total mass of the particles.

7. The granular fertilizer according to claim 6, characterized in that, The fermentation organic carrier, fulvic acid or potassium humate, and the chitosan-humic acid composite coating agent work synergistically to form an endogenous protective system for stabilizing the activity of the composite microbial agent during processing and storage.

8. The granular fertilizer for improving saline-alkali land according to claim 1, characterized in that, The thickness of the chitosan-humic acid composite coating layer is 70-140 μm.

9. A method for preparing granular fertilizer as described in any one of claims 1-11, characterized in that, Includes the following steps: Fermentation and composting of organic carriers: Crush the organic carrier raw materials to 20-40 mesh, add 0.5% urea by weight to adjust the carbon-nitrogen ratio to 25-30, inoculate with 0.3% enzyme agent by weight, and add milk or whey equivalent to 5%-10% of the dry weight of the organic carrier, and a collection of active Chinese medicine substances equivalent to 5% of the dry weight of the organic carrier. Adjust the moisture content to 55%-60%, carry out aerobic fermentation until the germination index of the material is ≥85%, and dry and cool for later use. Sequential mixing and microbial agent protection: First, the fermented organic carrier obtained from the fermentation and decomposition of the organic carrier in the first step is mixed with superphosphate, gypsum, sulfur powder, ferrous sulfate, potassium chloride, and bentonite; Second, fulvic acid or potassium humate and seaweed extract are added to the first mixture to obtain a second mixture; Third, the compound microbial agent and compound biological enzyme are diluted with part of the fermented organic carrier and added to the second mixture under the conditions of material temperature ≤35℃ and low-speed stirring to obtain the final mixture; Low-temperature pressing and structure formation: The final mixture obtained from the sequential mixing and microbial agent protection steps is moistened to a moisture content of 18%-20%, and granulated at room temperature using a roller extrusion granulator to control the particle size to 3-5mm; then the granules are subjected to a three-stage gradient drying process not exceeding 60℃, specifically: drying at 45-50℃ for 30 minutes, drying at 55-60℃ for 40 minutes, and drying at 40-45℃ for 20 minutes; finally, the granules are cooled to ≤30℃ to ensure that the moisture content of the granules is ≤8%; Coating and post-processing: The particles obtained from the low-temperature pressing and structure formation steps are coated with a chitosan-humic acid composite coating solution, and the weight gain of the coating is controlled at 1.0%-1.2%. Then, they are screened and packaged.

10. The application of a granular fertilizer as described in any one of claims 1-11 in the improvement of saline-alkali soil with pH ≥ 8.5 and / or EC ≥ 4 ms / cm.

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