Functional strain and enzyme preparation embedded slow-release soil remediation organic fertilizer and preparation process thereof

Abstract

The invention discloses a functional strain and enzyme preparation embedded slow-release soil remediation organic fertilizer and a preparation process thereof, and relates to the technical field of agricultural environment remediation. The compound fertilizer comprises a fertilizer matrix and a large number of triple-compound embedded microcapsules dispersed in the fertilizer matrix, and the compound fertilizer comprises the following components in percentage by weight: 85-92% of the fertilizer matrix and 8-15% of the triple-compound embedded microcapsules, the fertilizer matrix comprises 50%-65% of fermented organic matters, 15%-25% of weathered coal humic acid, 10%-15% of inorganic mineral nutrients and 5%-10% of biochar; the triple-compound embedded microcapsule comprises 40-50% of an inner active core, 20-30% of a middle lipid protection layer and 30-40% of an outer environment response shell, wherein the inner-layer active core comprises 2%-5% of functional strain freeze-dried powder, 1%-3% of a compound enzyme preparation and the balance of a protective agent. Physical isolation and chemical protection are provided for strains and enzymes by designing a triple embedding structure, and tests show that after the product is stored for 12 months under a normal-temperature dry condition, the survival rate of functional bacteria in the microcapsule can still be kept at 80% or above, and the retention rate of enzyme activity exceeds 70% and is far higher than that of a conventional product.

Description

Technical Field

[0001] This invention belongs to the field of agricultural environmental remediation technology, specifically a slow-release organic fertilizer for soil remediation with encapsulated functional strains and enzyme preparations, and its preparation process. Background Technology

[0002] Currently, soil remediation using microorganisms and enzymes has become a key technological direction for sustainable agricultural development. A variety of related products are already available on the market.

[0003] Compound microbial fertilizers are made by simply mixing one or more beneficial microorganisms with a carrier. Their mechanism of action is mainly to improve the soil microecology and promote nutrient transformation through the life activities of the microorganisms. However, the survival rate of the microorganisms in these products is low, and they are easily inactivated in the harsh environments of fertilizer processing, storage, and application to the soil, leading to unstable effects.

[0004] Enzyme-activated fertilizers, by adding cellulase, protease, urease, and other enzymes to fertilizers, aim to accelerate the decomposition of organic matter and the release of nutrients in the soil. However, free enzymes are easily degraded or inactivated in the environment, and their activity is short-lived, making it difficult to achieve a lasting effect.

[0005] Current slow-release fertilizer technologies primarily focus on the physical or chemical coating of fertilizer nutrients for slow release, such as using polymer coatings to control the release rate of nitrogen, phosphorus, and potassium. A few advanced technologies are beginning to explore encapsulating bioactive components, such as using multi-layered coating structures to encapsulate microorganisms or fungal spores. For example, one multifunctional bio-organic slow-release fertilizer employs a three-layer structure: an inner core of bio-organic masterbatch, an intermediate slow-release layer, and an outer fungal layer. However, this type of design does not adequately consider the protection of enzyme preparations and the synergistic release with microorganisms, and the environmental responsiveness of the encapsulation materials is relatively weak, resulting in a less "intelligent" release behavior.

[0006] In the pharmaceutical and probiotic fields, encapsulation technology is relatively mature. For example, the "triple encapsulation technology" achieves targeted release of probiotics into the human gut through the design of a gastric acid-insoluble polymer layer, an anti-bile lipid layer, and an active core layer. Similarly, enzyme-carrying liposome technology is used to protect enzyme preparations from damage by the digestive system. However, directly applying these technologies to the soil environment faces significant challenges because soil is a heterogeneous, multiphase, and open system with complex and variable environmental factors, placing special requirements on the biodegradability, environmental safety, and cost of encapsulation materials.

[0007] Based on existing technologies, active bio-fertilizers applied to soil remediation face the following pressing technical challenges: 1. Functional bacterial strains and enzymes are both bioactive substances. During high-temperature granulation, drying, storage, and after application to the soil, they are susceptible to significant inactivation due to factors such as high temperature, drought, salinity, ultraviolet radiation, and competition from indigenous microorganisms, resulting in short shelf life and poor field performance. 2. Existing slow-release technologies primarily control nutrient release, lacking precise regulation of functional bacteria and enzyme release. Microorganisms and enzymes often release rapidly in the initial application phase, failing to match the long-term process of crop root growth and soil remediation, leading to resource waste and short-lived effects. 3. Many products use single bacterial strains or enzymes, whose functions are limited in complex soil environments. For example, common microorganisms struggle to survive and reproduce in saline-alkali soils. Although studies have screened salt-tolerant bacteria from extreme environments, effective solutions for combining them with encapsulation slow-release technology to achieve both "stress tolerance" and "slow release" characteristics remain lacking. 4. Microorganisms and enzyme preparations have an inherent synergistic effect in soil remediation. The enzymes secreted by microorganisms can degrade pollutants, and the enzymatic products can also serve as a carbon source for microorganisms. However, existing technologies mostly physically mix the two and fail to achieve their orderly release and synergistic effect in time and space through material design.

[0008] The information disclosed above in this background section is only for enhancing the understanding of the background section of this invention, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0009] The primary objective of this invention is to overcome the aforementioned deficiencies of the prior art and provide a slow-release organic fertilizer for soil remediation that can maintain the activity of functional strains and enzyme preparations for a long period of time and with high efficiency.

[0010] Another objective of this invention is to provide a preparation process that can construct an environmentally responsive multiple encapsulation structure, enabling the intelligent release of functional strains and enzyme preparations at target times and locations based on soil environmental conditions.

[0011] A further objective of this invention is to significantly enhance the remediation efficacy and crop growth promotion effect of organic fertilizer in degraded soils such as saline-alkali and compacted soils by screening specific functional strains for extreme environments and combining them with stress-resistant enzyme preparations, and by utilizing biochar-humic acid composite carriers.

[0012] To achieve the above objectives, the present invention provides the following technical solution: a slow-release soil remediation organic fertilizer containing encapsulated functional strains and enzyme preparations, comprising a fertilizer matrix and a large number of triple-layer composite encapsulated microcapsules dispersed therein, comprising, by weight percentage, 85%-92% fertilizer matrix and 8%-15% triple-layer composite encapsulated microcapsules;

[0013] The fertilizer substrate consists of 50%-65% fermented organic matter, 15%-25% weathered coal humic acid, 10%-15% inorganic mineral nutrients, and 5%-10% biochar;

[0014] The triple-layer composite encapsulated microcapsules consist of an inner active core (40%-50%), a middle lipid protective layer (20%-30%), and an outer environmentally responsive shell (30%-40%).

[0015] The inner active core consists of 2%-5% lyophilized functional strain powder, 1%-3% compound enzyme preparation, and the remainder being a protective agent; the middle lipid protective layer consists of liposomes and thermosensitive polymers; and the outer environmental responsive shell consists of a gel matrix and functional fillers.

[0016] Preferably, the fermented organic matter is a mixture of livestock and poultry manure, crop straw or kitchen waste that has been rapidly fermented at high temperature with a special EM compound microbial agent, and the organic matter content is ≥50%.

[0017] Preferably, the functional strain comprises at least two salt-tolerant growth-promoting bacteria isolated and screened from extreme saline-alkali environments, and the total viable count of the lyophilized powder of the functional strain is not less than 1×10⁻⁶. 10 CFU / g microcapsules

[0018] Preferably, the compound enzyme preparation comprises alkali-resistant cellulase, salt-resistant protease, and phytase; the protective agent comprises trehalose and skim milk powder.

[0019] Preferably, the liposomes are prepared by thin-film dispersion of soybean phospholipids and cholesterol in a molar ratio of 7:3, encapsulating an inner active core; and 0.5%-2% of a thermosensitive polymer is incorporated into the liposomes.

[0020] Preferably, the gel matrix is ​​a hydrogel formed by crosslinking carboxymethyl chitosan and humic acid; the functional filler is nanoscale modified biochar particles and attapulgite embedded in the gel.

[0021] This invention also provides a process for preparing a slow-release organic fertilizer for soil remediation containing encapsulated functional strains and enzyme preparations, comprising the following steps:

[0022] Step 1: Preparation of microcapsules containing functional strains and enzyme preparations:

[0023] Step 1.1, Strain Cultivation and Preparation: The preserved salt-tolerant growth-promoting functional strains were inoculated into liquid culture medium and fermented at high density at 30-37℃ until the late stationary phase; the bacterial cells were collected by centrifugation and washed with sterile physiological saline; the bacterial sludge was mixed with compound enzyme preparation and protectant in proportion at low temperature, and then vacuum freeze-dried to obtain active core powder;

[0024] Step 1.2, Liposome Encapsulation to Form the Middle Layer: Soybean phospholipids and cholesterol are dissolved in an organic solvent and rotary evaporated to form a uniform lipid film; a buffer solution containing a temperature-sensitive polymer is added, and the mixture is hydrated and exfoliated to form multilayer liposomes; the active core powder obtained in the previous step is dispersed in a buffer solution, and the liposomes are encapsulated using an ultrasonic-extrusion method to form primary encapsulated particles; unencapsulated substances are removed by centrifugation and washing.

[0025] Step 1.3: Forming the outer shell with outer gel coating: Prepare a carboxymethyl chitosan solution and a humic acid solution, and disperse nano-sized modified biochar particles and attapulgite clay in them under stirring; disperse the liposome-embedded particles obtained in the previous step in the mixture, then add a crosslinking agent, and carry out an in-situ crosslinking reaction under gentle stirring to form a uniform gel film on the particle surface; obtain triple composite embedded microcapsules by sieving;

[0026] Step 2: Fermentation and activation of organic fertilizer substrate:

[0027] Step 2.1, Raw material pretreatment: Crush and mix the mixture of livestock and poultry manure, crop straw or kitchen waste, and adjust the carbon-nitrogen ratio and moisture content;

[0028] Step 2.2, High-temperature rapid fermentation: Inoculate the pretreated raw materials with a special EM compound microbial agent to thoroughly kill pathogens and insect eggs; then control the temperature at 55-65℃ and carry out aerobic fermentation for 12-24 hours until the material is loose and odorless;

[0029] Step 2.3, Matrix compounding and activation: Mix fermented compost with weathered coal humic acid, a certain proportion of coated slow-release fertilizer, biochar and trace element minerals evenly; spray a small amount of liquid containing humic acid activating bacteria, and carry out short-term post-ripening activation during the composting process to further enhance the biological activity of the matrix.

[0030] Step 3: Integrated granulation of the final product

[0031] Step 3.1, Mixing: The prepared triple composite encapsulated microcapsules and the activated organic fertilizer matrix are thoroughly and gently mixed evenly in a double helix mixer according to the target ratio to avoid high-speed shearing that could damage the microcapsule structure;

[0032] Step 3.2, Granulation: Spray an appropriate amount of environmentally friendly binder into the mixture, and then granulate it under low temperature conditions using a roller extrusion or disc granulator. This low temperature condition is key to ensuring the biological activity in the microcapsules.

[0033] Step 3.3, Drying and Sieving: The shaped granules are placed in a low-temperature fluidized bed dryer for drying; finally, they are sieved to obtain uniform granular products, which are then metered and packaged.

[0034] Preferably, in step 1.1, the bacterial sludge is mixed uniformly with the compound enzyme preparation and the protectant at 4°C in a certain proportion; in step 1.2, the particle size of the primary encapsulated particles ranges from 200 to 500 nanometers; and in step 1.3, the particle size of the triple compound encapsulated microcapsules ranges from 0.1 to 0.5 mm.

[0035] Preferably, in step 2.1, the carbon-to-nitrogen ratio is adjusted to 25-30:1 and the moisture content is adjusted to 55%-65%; in step 2.2, a reactor equipped with heating and stirring devices is used to raise the temperature to 105°C within 1-2 hours and maintain it for a period of time to thoroughly kill pathogens and insect eggs; in step 2.3, the weathered coal humic acid is pulverized through a 60-mesh sieve.

[0036] Preferably, in step 3.2, the low temperature condition is ≤50℃; in step 3.3, the product is dried under warm air at 40-45℃ until the moisture content is less than 15%, and the particle size of the granular product is 2-4 mm.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. This invention provides physical isolation and chemical protection for strains and enzymes through the design of a triple encapsulation structure. After testing, the survival rate of functional bacteria in the microcapsules can still be maintained at over 80% and the enzyme activity retention rate can exceed 70% after 12 months of storage under normal temperature and dry conditions, which is far higher than that of conventional products.

[0039] 2. After the product of this invention is applied to the soil, the outer gel swells according to the soil pH, allowing water and ions to slowly penetrate. Only when the soil temperature reaches the suitable temperature for the peak growth season of crops will the middle layer open and release the core active substances, thereby achieving synchronization between biological activity and crop demand cycle, and greatly improving utilization rate.

[0040] 3. The product of this invention has excellent soil remediation and crop growth promotion effects. Trials in saline-alkali land in Xinjiang Uygur Autonomous Region, Inner Mongolia Autonomous Region and other places have shown that after applying this product, the soil pH value decreased by 0.5-1.0 units, the salt content decreased by 20-30%, the soil organic matter and available nutrient content increased significantly, the crop emergence rate increased by about 20%, the seedling survival rate exceeded 90%, and the final yield increased by more than 20%.

[0041] 4. All raw materials of this invention, including the encapsulation materials, are natural or biodegradable substances with no risk of environmental residue. The product restores soil through biological pathways, reducing dependence on chemical amendments and fertilizers, which is in line with the development direction of ecological agriculture. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0043] Figure 1 This is a schematic diagram of the preparation process of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0045] Example 1:

[0046] A slow-release organic fertilizer for soil remediation containing encapsulated functional strains and enzyme preparations is composed of a fertilizer matrix and a large number of triple-layer encapsulated microcapsules dispersed therein, comprising 85%-92% fertilizer matrix and 8%-15% triple-layer encapsulated microcapsules by weight percentage.

[0047] The fertilizer substrate consists of 50-65% fermented organic matter, 15%-25% weathered coal humic acid, 10%-15% inorganic mineral nutrients, and 5%-10% biochar.

[0048] Specifically, the fermented organic matter uses a mixture of livestock and poultry manure, crop straw, or kitchen waste that has undergone high-temperature rapid fermentation with a specialized EM compound microbial agent. The organic matter content is ≥50%, and harmful bacteria and insect eggs have been completely eliminated. Weathered coal humic acid, as a highly efficient cementing and bonding material and ion exchange carrier, enhances particle strength and chelates harmful ions in the soil, stimulating plant growth. Inorganic mineral nutrients include macroelements such as nitrogen, phosphorus, and potassium, as well as microelements such as calcium, magnesium, sulfur, and silicon. Some nitrogen sources can be polymer-coated for longer-term slow release. Biochar, as part of the matrix, works synergistically with humic acid to enhance the soil's carbon sequestration, water retention, and stable microbial community functions.

[0049] The triple-layer composite encapsulated microcapsules consist of an inner active core (40%-50%), a middle lipid protective layer (20%-30%), and an outer environmentally responsive shell (30%-40%).

[0050] The inner active core consists of 2-5% lyophilized functional bacterial strain powder, 1-3% compound enzyme preparation, and the remainder being a protective agent; the middle lipid protective layer consists of liposomes and thermosensitive polymers; and the outer environmental responsive shell consists of a gel matrix and functional fillers.

[0051] Specifically, the functional strains include at least two salt-tolerant growth-promoting bacteria isolated and screened from extreme saline-alkali environments, such as a strain with a high capacity for secreting plant growth hormones and a strain with a strong ability to dissolve insoluble phosphates. The total viable count of the lyophilized powder of the functional strains is not less than 1 × 10⁻⁶. 10 CFU / g microcapsules

[0052] Specifically, the compound enzyme preparation contains alkali-tolerant cellulase, salt-tolerant protease, and phytase. These enzymes maintain high activity under saline-alkali conditions, accelerating the mineralization of soil organic matter and organophosphorus compounds. Protectants include trehalose and skim milk powder, used for stability protection during freeze-drying and long-term storage of the strains.

[0053] Specifically, the liposomes are prepared by thin-film dispersion using soybean phospholipids and cholesterol in a molar ratio of 7:3, encapsulating an inner active core; 0.5%-2% of a thermosensitive polymer—poly(N-isopropylacrylamide) fragment—is incorporated into the liposomes. When the soil temperature reaches a set value, the integrity of the middle lipid protective layer is disrupted, accelerating the release of the inner layer substances.

[0054] Specifically, the gel matrix is ​​a hydrogel formed by crosslinking carboxymethyl chitosan and humic acid. The swelling behavior of the gel is affected by pH, and the swelling degree and porosity increase in saline-alkali soil, thus allowing water and ions to penetrate more easily into the middle layer. The functional fillers are nanoscale modified biochar particles and attapulgite embedded in the gel. Biochar provides porous adsorption sites and can load trace elements, while attapulgite can enhance the mechanical strength of the gel and adsorb ammonium ions.

[0055] Example 2:

[0056] A process for preparing a slow-release organic fertilizer for soil remediation containing encapsulated functional bacterial strains and enzyme preparations includes the following steps:

[0057] Step 1: Preparation of microcapsules containing functional strains and enzyme preparations:

[0058] Step 1.1, Strain Cultivation and Preparation: The preserved salt-tolerant growth-promoting functional strains were inoculated into liquid culture medium and fermented at high density at 30-37℃ until the late stationary phase; the bacterial cells were collected by centrifugation and washed with sterile physiological saline; the bacterial sludge was mixed with compound enzyme preparation and protectant in proportion at a low temperature of 4℃, and then vacuum freeze-dried to obtain active core powder;

[0059] Step 1.2, Liposome Encapsulation to Form the Middle Layer: Soybean phospholipids and cholesterol are dissolved in an organic solvent and rotary evaporated to form a uniform lipid film; a buffer solution containing a temperature-sensitive polymer is added, followed by hydration and exfoliation to form multilayer liposomes; the active core powder obtained in the previous step is dispersed in a buffer solution, and the liposomes are encapsulated using an ultrasonic-extrusion method to form primary encapsulated particles with a particle size range of 200-500 nanometers; unencapsulated substances are removed by centrifugation and washing.

[0060] Step 1.3: Forming the outer shell with outer gel coating: Prepare a carboxymethyl chitosan solution and a humic acid solution, and disperse nano-sized modified biochar particles and attapulgite clay in them under stirring; disperse the liposome-embedded particles obtained in the previous step in the mixture, then add a crosslinking agent, and carry out an in-situ crosslinking reaction under gentle stirring to form a uniform gel film on the particle surface; through sieving, obtain triple-layer composite-embedded microcapsules with a particle size range of 0.1-0.5 mm;

[0061] Step 2: Fermentation and activation of organic fertilizer substrate:

[0062] Step 2.1, Raw material pretreatment: Crush and mix the mixture of livestock and poultry manure, crop straw or kitchen waste, adjust the carbon-to-nitrogen ratio to 25-30:1, and the moisture content to 55%-65%;

[0063] Step 2.2, High-temperature rapid fermentation: Inoculate the pretreated raw materials with a special EM compound microbial agent. Use a reactor with heating and stirring devices to raise the temperature to 105℃ within 1-2 hours and maintain it for a period of time to thoroughly kill pathogens and insect eggs. Then control the temperature at 55-65℃ and carry out aerobic fermentation for 12-24 hours until the material is loose and odorless.

[0064] Step 2.3, Matrix compounding and activation: Mix fermented compost with weathered coal humic acid pulverized through a 60-mesh sieve, a certain proportion of coated slow-release fertilizer, biochar and trace element minerals evenly; spray a small amount of liquid containing humic acid activating bacteria, and carry out short-term post-ripening activation during the composting process to further enhance the biological activity of the matrix.

[0065] Step 3: Integrated granulation of the final product

[0066] Step 3.1, Mixing: The prepared triple composite encapsulated microcapsules and the activated organic fertilizer matrix are thoroughly and gently mixed evenly in a double helix mixer according to the target ratio to avoid high-speed shearing that could damage the microcapsule structure;

[0067] Step 3.2, Granulation: Spray an appropriate amount of environmentally friendly binder, polyvinyl alcohol dilute solution or lignin sulfonate solution, into the mixture, and then granulate it using a roller extrusion or disc granulator at a low temperature of ≤50℃. This low temperature condition is the key to ensuring the biological activity in the microcapsules.

[0068] Step 3.3, Drying and Sieving: Place the shaped granules in a low-temperature fluidized bed dryer and dry them under warm air at 40-45℃ until the moisture content is less than 15%; finally, sieve them to obtain uniform granular products with a particle size of 2-4 mm, and then measure and package them.

[0069] The encapsulation structure of this invention differs from simple physical mixing or a single membrane; instead, it creatively constructs a triple structure consisting of an inner active core, a middle lipid protective layer, and an outer environmentally responsive shell. This design draws inspiration from the targeted release of human probiotics, but innovatively applies it to an open soil system. The middle lipid protective layer acts as a crucial switch, its release triggered by soil temperature or plant root signals, achieving on-demand release and avoiding ineffective release.

[0070] This invention is the first to integrate and protect extreme-environment microorganisms and stress-resistant enzyme preparations through encapsulation technology. The selected strains and enzymes themselves have stronger environmental tolerance, and the encapsulation process further enhances their colonization and functional capabilities in harsh soils.

[0071] The outer shell of this invention uses a gel composite material. Biochar and humic acid are not only protective materials, but are also recognized soil conditioners. By combining them with a pH-responsive gel, the residue in the outer shell can continue to improve the soil and retain water and fertilizer after the microcapsules have released their bioactive substances, thus realizing the full utilization of the material.

[0072] This invention's preparation process seamlessly integrates and optimizes the process parameters of high-density microbial fermentation and freeze-drying technology, liposome encapsulation technology, in-situ gel polymerization technology, and high-temperature granulation technology for organic fertilizers. Particularly in the granulation stage, by adjusting the binder and process temperature, it ensures that the encapsulated microcapsules are not damaged at high temperatures, thus solving the technical bottleneck of activity preservation in bio-fertilizer production.

[0073] Example 3: A soil remediation organic fertilizer specifically for cotton in moderately saline-alkali soil

[0074] Preparation of composite encapsulated microcapsules: A salt-tolerant, IAA-producing strain A isolated from Dabancheng Salt Lake and a highly efficient phosphate-solubilizing strain B isolated from local saline-alkali soil were selected. The strains were fermented and centrifuged separately. The bacterial sludge was then mixed with alkali-tolerant cellulase and trehalose at a ratio of 100:10:50 (by weight) and freeze-dried to obtain the core powder. Liposomes were prepared using soybean phospholipids, cholesterol, and 1% thermosensitive polymer to encapsulate the core powder. A coating solution was prepared using carboxymethyl chitosan, humic acid extract, and 300-mesh biochar powder, and the liposome particles were fluidized bed coated to form microcapsules. The final microcapsules comprised 10% of the total fertilizer weight.

[0075] Organic fertilizer substrate preparation: Sheep manure and cotton stalks are fermented with EM bacteria, and then mixed with 25% weathered coal humic acid, 8% coated urea, 5% biochar and 2% potassium sulfate.

[0076] Integrated granulation: Microcapsules are mixed with a matrix, and granulated and dried at a temperature below 45°C using a 1% lignin sulfonate solution as a binder to obtain the final product.

[0077] The following study verifies the effects of the product of this invention on the remediation and cotton growth promotion in moderately saline-alkali soil, clarifying its advantages compared to conventional products. The experimental site was a location in Xinjiang Uygur Autonomous Region, with soil conditions of pH 8.5, salt content 0.3%, and organic matter content <1%, belonging to a typical moderately saline-alkali cotton field.

[0078] This experiment consisted of 4 treatment groups, each with 3 replicates, arranged in a randomized block design, with a plot size of 30m². 2 The group receiving this invention applied the organic fertilizer from Example 3 at a rate of 150 kg / mu. The group receiving ordinary organic fertilizer applied ordinary commercial organic fertilizer with equal nutrient content, using a simple mixture of bacteria and enzymes without any encapsulation structure, at a rate of 150 kg / mu. The group receiving commercially available slow-release fertilizer applied commercially available slow-release compound microbial fertilizer containing salt-tolerant bacteria, with a single-layer coating, at a rate of 150 kg / mu. The blank control group received no fertilizer and only conventional irrigation.

[0079] All fertilizers were applied as basal fertilizer, spread evenly and lightly tilled to mix the fertilizer one week before sowing.

[0080] The following indicators were observed in each group:

[0081] Soil physicochemical properties: Soil samples from the 0-20 cm topsoil layer were collected before sowing, during the seedling stage, during the flowering stage, and after harvest to determine pH, electrical conductivity (EC), organic matter, and available nitrogen, phosphorus, and potassium.

[0082] Microbial activity: The number of functional bacteria in the soil was determined by plate counting; soil enzyme activity was determined by fluorescent substrate method.

[0083] Cotton growth indicators: emergence rate, plant height, root length, biomass, and seed cotton yield.

[0084] The experimental results are shown in Table 1 below.

[0085] Table 1. Results of detection indicators for each group in Example 3

[0086] index Blank control group Ordinary organic fertilizer group Commercially available slow-release fertilizer packs This invention group Emergence rate (%) 45±3 65±4 70±5 88±3 Plant height (cm, flowering period) 45±2 68±3 72±4 85±3 Root length (cm, harvest time) 18±2 25±3 28±2 35±3 Soil pH (post-harvest) 8.5±0.1 8.2±0.1 8.0±0.2 7.8±0.1 Soil EC (mS / cm, post-harvest) 3.0±0.2 2.5±0.1 2.3±0.2 2.1±0.1 Soil organic matter (g / kg) 8.5±0.5 10.2±0.6 11.0±0.7 13.5±0.8 Functional bacterial count (log CFU / g) 3.2±0.3 5.8±0.4 6.2±0.5 7.5±0.4 Cellulase activity (μg / g·h) 12±2 25±3 30±4 48±5 Seed cotton yield (kg / mu) 210±15 290±20 310±18 380±22

[0087] As shown above, the emergence rate, plant height, and root length of the group using this invention were significantly better than those of other groups (P < 0.05), indicating that the product of this invention can significantly alleviate salt-alkali stress and promote early seedling establishment and root development in cotton. The soil pH of the group using this invention decreased most significantly, EC decreased the most, and organic matter increased the most, indicating that this invention is effective in improving saline-alkali soil and enhancing soil fertility. The number of functional bacteria and enzyme activity in the soil of the group using this invention were significantly higher than those of other groups, indicating that the encapsulation structure effectively protected the bacterial strains and enzyme activity, achieving slow-release and long-lasting effects. Compared with the group using ordinary organic fertilizer with the same nutrients, the cotton emergence rate of the group using this invention increased from 65% to 88%. The seed cotton yield of the group using this invention increased by 81% compared to the blank control group, by 31% compared to the ordinary organic fertilizer group, and by 23% compared to the commercially available slow-release fertilizer group, demonstrating a significant yield increase.

[0088] Example 4: A soil remediation organic fertilizer for alleviating continuous cropping obstacles in greenhouse vegetable areas

[0089] Objective: To address the problems of increased soil-borne diseases and soil compaction caused by continuous cropping of greenhouse cucumbers.

[0090] This embodiment is prepared according to the contents of Embodiments 1 and 2, except that the functional bacterial strains are replaced with Trichoderma and Bacillus subtilis, which have anti-pathogenic fungal activity; the compound enzyme preparation is replaced with chitinase and glucanase to degrade the cell walls of pathogenic fungi; the thermosensitive polymer of the middle lipid protective layer is adjusted to an ester bond material sensitive to phenolic acids secreted by roots, which accelerates the release of biocontrol bacteria when root secretion increases; and the pH response range of the outer gel is adjusted to adapt to possible acidification of the facility soil.

[0091] The following is an experiment to verify the remediation effect of the product of this invention in soils with continuous cropping obstacles, particularly its role in inhibiting soil-borne diseases and improving soil structure. The experimental site was a greenhouse in Shouguang, Shandong Province, where cucumbers had been continuously cropped for 5 years. The soil conditions were: pH 6.8, EC 2.5 mS / cm, and Fusarium wilt incidence rate >30%.

[0092] This experiment consisted of 4 treatment groups, each with 3 replicates, arranged in a randomized block design, with a plot size of 30m². 2 .

[0093] The organic fertilizer of Example 4 was applied to this invention at a rate of 200 kg / mu.

[0094] The ordinary bio-organic fertilizer group was treated with ordinary bio-organic fertilizer containing the same amount of microbial enzymes, without any encapsulation structure, at a rate of 200 kg / mu. The conventional fertilizer group was disinfected with dazomet before sowing, followed by conventional compound fertilizer. The conventional management group only received conventional compound fertilizer, without any biological agents.

[0095] The following indicators were observed in each group:

[0096] Soil physicochemical properties: bulk density, porosity, EC, pH.

[0097] Disease incidence rate: Fusarium wilt incidence rate.

[0098] Soil microbial flora: number of pathogenic fungi and number of beneficial bacteria.

[0099] Cucumber growth and yield: plant height, stem diameter, number of fruits, and yield.

[0100] The experimental results are shown in Table 2 below.

[0101] Table 2. Results of detection indicators for each group in Example 4

[0102] index Routine Management Group Ordinary biological organic fertilizer group conventional fertilizer group This invention group Fusarium wilt incidence rate (%) 32±4 15±3 20±3 8±2 Soil bulk density (g / cm³) 1.45±0.05 1.40±0.04 1.38±0.03 1.32±0.03 Soil porosity (%) 38±2 42±3 44±2 48±3 Pathogenic fungal count (log CFU / g) 5.2±0.3 3.8±0.2 4.2±0.3 3.0±0.2 Trichoderma count (log CFU / g) 3.0±0.2 4.5±0.3 5.0±0.4 6.2±0.3 Cucumber yield per plant (kg) 2.8±0.3 3.5±0.4 3.8±0.3 4.5±0.4 Total yield (kg / mu) 4200±200 5200±250 5600±300 6700±350

[0103] As shown above, the disease control effect was as follows: the incidence of Fusarium wilt in the group of this invention was the lowest, significantly lower than that in the ordinary bio-organic fertilizer group and the conventional fertilizer group (P < 0.05), indicating that the encapsulation structure achieved synergistic slow release of biocontrol bacteria and enzymes, continuously inhibiting pathogens. The soil bulk density and porosity in the group of this invention were the lowest, indicating that the product of this invention helps alleviate soil compaction and improve aeration. The number of pathogenic fungi was the lowest and the number of beneficial Trichoderma was the highest in the group of this invention, indicating that the product can effectively regulate the soil microecology. The cucumber yield in the group of this invention was significantly higher than that in other groups, and the uniformity and marketability of the fruits were also significantly improved.

[0104] In summary, this invention demonstrates superior performance in both saline-alkali land remediation and mitigation of continuous cropping obstacles, significantly outperforming ordinary organic fertilizers and commercially available similar products. The triple encapsulation structure is key, achieving efficient protection, slow-release, and synergistic effects of bacteria and enzymes, thus maintaining long-term activity in complex soil environments. The experimental data and analysis above fully demonstrate the scientific validity, effectiveness, and promotional value of this invention, providing solid data support for its application in agricultural soil remediation. The above examples also show that this invention can be flexibly adapted to different soil remediation scenarios by adjusting the functional strains, enzyme types, and the response characteristics of the encapsulation materials, possessing broad applicability and significant application potential.

[0105] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations, characterized in that: Consists of a fertilizer matrix and a large number of triple composite embedded microcapsules dispersed therein, including 85%-92% of the fertilizer matrix and 8%-15% of the triple composite embedded microcapsules by weight percentage; The fertilizer matrix includes fermented organic matter 50-65%, weathered coal humic acid 15%-25%, inorganic mineral nutrients 10%-15%, and biochar 5%-10%; The triple composite embedded microcapsules include an inner layer active core 40%-50%, a middle layer lipid protection layer 20%-30%, and an outer layer environment response shell 30%-40%; Among them, the inner layer active core includes functional strain freeze-dried powder 2-5%, composite enzyme preparation 1-3%, and the rest protective agent; the middle layer lipid protection layer includes liposomes and temperature-sensitive polymers; the outer layer environment response shell includes gel matrix and functional filler.

2. The slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to claim 1, characterized in that: The fermented organic matter is a mixture of livestock and poultry manure, crop straw, or kitchen waste, which is rapidly fermented by special EM composite microbial agent at high temperature, and the organic matter content is ≥50%.

3. The slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to claim 1, characterized in that: The functional strain comprises at least two salt-tolerant growth-promoting bacteria isolated and screened from a saline-alkali extreme environment, and the total viable bacteria count of the functional strain freeze-dried powder is not less than 1×10 10 CFU / g microcapsules.

4. The slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to claim 1, characterized in that: The composite enzyme preparation contains alkali-resistant cellulase, salt-tolerant protease, and phytase; the protective agent includes trehalose and skimmed milk powder.

5. The slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to claim 1, characterized in that: The liposomes are prepared by the thin film dispersion method with molar ratio of 7:3 of soybean phospholipid and cholesterol, which wrap the inner layer active core; 0.5%-2% of temperature-sensitive polymers are added to the liposomes.

6. The slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to claim 1, characterized in that: The gel matrix is a hydrogel formed by cross-linking carboxymethyl chitosan and humic acid; the functional filler is nano-sized modified biochar particles and attapulgite embedded in the gel.

7. The preparation process of the slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to any one of claims 1-6, characterized in that, It includes the following steps: Step 1, preparation of composite embedded microcapsules of functional strains and enzyme preparation: Step 1.1, strain culture and preparation: inoculate the preserved salt-tolerant growth-promoting functional strains into liquid medium, and ferment at high density at 30-37℃ until the late stationary phase; collect the bacterial cells by centrifugation, and wash with sterile physiological saline; uniformly mix the bacterial slurry with composite enzyme preparation and protective agent at low temperature, and then vacuum freeze-dry to obtain active core powder; Step 1.2, formation of middle layer by liposome coating: dissolve soybean phospholipid and cholesterol in an organic solvent, and rotary evaporate to form a uniform lipid film; add a buffer solution containing temperature-sensitive polymers, hydrate and peel off to form multilayer liposomes; disperse the active core powder obtained in the previous step in the buffer solution, and use ultrasonic-extrusion method to encapsulate it with liposomes to form primary embedded particles; remove the unencapsulated substances by centrifugal washing; Step 1.3, outer gel coating to form the shell: prepare carboxymethyl chitosan solution and humic acid solution, and disperse nano-sized modified biochar particles and attapulgite in them under stirring; Disperse the liposome-embedded particles obtained in the previous step in the mixed solution, then add a cross-linking agent, and perform in-situ cross-linking reaction under gentle stirring to form a uniform gel film on the surface of the particles; screen to obtain triple composite embedded microcapsules; Step 2, fermentation and activation of organic fertilizer matrix: Step 2.1, raw material pretreatment: crush and mix the mixture of livestock and poultry manure, crop straw, or kitchen waste, and adjust the carbon-nitrogen ratio and moisture content; Step 2.2, high-temperature rapid fermentation: inoculate the pretreated raw material with a special EM complex microbial inoculant to completely kill pathogenic bacteria and insect eggs; then control the temperature at 55-65℃ and perform aerobic fermentation for 12-24 hours until the material is loose and odorless; Step 2.3, substrate compounding and activation: uniformly mix the fermented and decomposed material with weathered coal humic acid, a certain proportion of coated slow-release fertilizer, biochar, and medium and trace element minerals; spray a small amount of liquid containing humic acid activation bacteria, and perform short-term post-maturation activation during the stacking process to further enhance the biological activity of the substrate; Step 3, integrated granulation of the final product Step 3.1, mixing: uniformly and gently mix the prepared triple-composite embedded microcapsules with the activated organic fertilizer substrate according to the target ratio in a double-screw mixer to avoid high-speed shearing damage to the microcapsule structure; Step 3.2, granulation: spray an appropriate amount of environmentally friendly binder into the mixed material, and then use roller extrusion or disc granulator under low-temperature conditions for granulation, which is crucial to ensure the biological activity of the microcapsules; Step 3.3, drying and screening: dry the formed granules in a low-temperature fluidized bed dryer; finally, screen to obtain uniform granular products for metering and packaging.

8. The preparation process of the soil remediation organic fertilizer for embedding functional strains and enzyme preparation according to claim 7, characterized in that: In step 1.1, uniformly mix the bacterial sludge with the composite enzyme preparation and the protective agent at 4℃; in step 1.2, the primary embedded particles have a particle size range of 200-500 nanometers; in step 1.3, the triple-composite embedded microcapsules have a particle size range of 0.1-0.5 mm.

9. The preparation process of the soil remediation organic fertilizer for embedding functional strains and enzyme preparation according to claim 7, characterized in that: In step 2.1, adjust the carbon-nitrogen ratio to 25-30:1 and the moisture content to 55%-65%; in step 2.2, use a reactor with heating and stirring devices to raise the temperature to 105℃ within 1-2 hours and maintain it for a period of time to completely kill pathogenic bacteria and insect eggs; in step 2.3, the weathered coal humic acid is crushed to pass through a 60-mesh sieve.

10. The preparation process of the slow-release soil remediation organic fertilizer embedding functional strains and enzyme preparations according to claim 7, characterized in that: In step 3.2, the low-temperature condition is ≤50℃; in step 3.3, dry at 40-45℃ warm air until the moisture content is less than 15%, and the granular product has a particle size of 2-4 mm. In step 3.2, the low-temperature condition is ≤50℃; in step 3.3, dry at 40-45℃ warm air until the moisture content is less than 15%, and the granular product has a particle size of 2-4 mm.

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