Microbial compound fertilizer and preparation method thereof

Abstract

The invention discloses a microbial compound fertilizer and a preparation method thereof, and relates to the technical field of organic fertilizers. The microbial compound fertilizer comprises the following raw materials in parts by mass: 35-55 parts of an inorganic fertilizer matrix; 30-45 parts of a modified organic carrier; 2-8 parts of a compound microbial agent; and 3-6 parts of a medium trace element additive. Through a modified carrier thought of'enzymolysis fermentation plant source organic matter + mineral source potassium fulvic acid + specific plant growth promoter ', the organic part is easier to use, and the carrier has more perfect water and fertilizer retention and buffer environment, so that the problems of slow decomposition, mismatched fertilizer supply, weak water and fertilizer retention and the like of the traditional carrier are solved.

Description

Technical Field

[0001] This invention relates to the field of organic fertilizer technology, specifically to a microbial compound fertilizer and its preparation method. Background Technology

[0002] In the process of agricultural modernization, microbial compound fertilizers have become a key fertilizer type for solving soil degradation and improving crop quality because they combine the rapid effects of inorganic fertilizers, the soil-improving properties of organic fertilizers, and the growth-promoting and disease-resistant properties of microbial agents. However, existing microbial compound fertilizers still have many technical bottlenecks, with the core pain points concentrated on the performance defects of organic carriers and insufficient synergistic effects between microorganisms and nutrients.

[0003] Traditional microbial compound fertilizers often use unmodified or simply fermented organic carriers (such as straw and livestock manure). These carriers have significant drawbacks: First, the decomposition of large organic molecules is slow, and the nutrient release cycle does not match the crop's nutrient requirements, resulting in insufficient nutrient supply in the early stages and easy nutrient deficiency in the later stages. Second, the carriers have poor physicochemical properties, with a simple pore structure and weak water and fertilizer retention capacity, making it difficult to form a suitable microenvironment for microbial survival. This leads to a significant decrease in the activity of compound microbial agents during granulation, drying, and soil application, and the total number of effective live bacteria is likely to be lower than the industry standard. Third, the carriers lack targeted modification treatment and do not incorporate technologies such as enzymatic hydrolysis and functional component compounding, resulting in an imbalanced carbon-nitrogen ratio and an inability to effectively regulate soil pH. Long-term use can easily exacerbate soil compaction or acidification.

[0004] Crucially, existing organic carrier modification technologies are still immature. Some technologies only treat the carrier through simple crushing or conventional fermentation, without introducing enzymatic hydrolysis to break down macromolecules such as cellulose and proteins, or incorporating functional components such as mineral-derived potassium humate and specialized plant growth promoters. This results in insufficient protection of microorganisms by the carrier and difficulty in synergistically improving fertilizer nutrient utilization and crop growth promotion effects. Furthermore, traditional carriers have poor compatibility with inorganic fertilizer substrates and micronutrient additives, and problems such as insufficient particle strength and nutrient loss easily occur during granulation, further limiting the field application effects of microbial compound fertilizers.

[0005] Therefore, developing high-performance modified organic carriers and optimizing their physicochemical properties through scientific modification processes to provide a stable substrate for microorganisms while achieving efficient nutrient release and synergistic promotion of crop growth has become a core requirement for breaking through the technical bottlenecks of existing microbial compound fertilizers and improving the overall efficiency of fertilizers. This is of great significance for promoting the sustainable development of ecological agriculture. Summary of the Invention

[0006] The purpose of this invention is to address the problems in existing technologies, such as insufficient modification of organic carriers, easy decline in microbial activity, and poor synergistic effect of nutrients. It provides a microbial compound fertilizer and its preparation method, which uses a modified organic carrier composed of enzymatically hydrolyzed plant-derived organic matter, mineral-derived potassium humate, and specific plant growth promoters as its core, combined with precisely proportioned inorganic fertilizer substrates, highly efficient compound microbial agents, and synergistic additives. This fertilizer exhibits balanced nutrient release, stable microbial activity, and combines soil improvement, growth promotion, and quality enhancement effects.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A microbial compound fertilizer comprises the following raw materials in parts by weight: Inorganic fertilizer substrate: 35-55 parts; 30-45 parts of modified organic carrier; 2-8 parts of compound microbial inoculant; 3-6 parts of trace element additives; And 0.5-2 parts of synergistic adjuvants; The modified organic carrier is a mixture of plant-derived organic matter that has undergone enzymatic hydrolysis and fermentation, mineral-derived potassium humate, and plant growth promoters. The plant growth promoter is N-(2-(2-(1H-indol-3-yl)acetamido)ethyl)-2-hydroxybenzamide.

[0008] Furthermore, the structure of the N-(2-(2-(1H-indol-3-yl)acetamido)ethyl)-2-hydroxybenzamide is as follows: .

[0009] Furthermore, the synthetic route for N-(2-(2-(1H-indol-3-yl)acetamido)ethyl)-2-hydroxybenzamide is as follows: .

[0010] Furthermore, the compound microbial agent is composed of Bacillus subtilis. Bacillus subtilis gelatinous spore-forming bacteria Paenibacillus mucilaginosus and Trichoderma harzianum Trichoderma harzianum composition; The effective viable count ratio of Bacillus subtilis, Bacillus mucilaginosus, and Trichoderma harzianum is 2-3:1-2:1; and the total effective viable count of the compound microbial agent is ≥5.0×10⁻⁶. 9 CFU / g.

[0011] Furthermore, the inorganic fertilizer matrix is ​​composed of urea, monoammonium phosphate, and potassium sulfate mixed in a mass ratio of 1.5-2.0:1:1.2-1.5.

[0012] Furthermore, the mass ratio of plant-derived organic matter, mineral-derived potassium humate, and plant growth promoter in the modified organic carrier is 50-70:20-40:0.1-1.0.

[0013] Furthermore, the synergistic agent is one or a combination of several of polyglutamic acid, chitosan oligosaccharide, and polyaspartic acid.

[0014] Furthermore, the trace element additives are one or more of EDTA chelated calcium, EDTA chelated magnesium, borax, and zinc sulfate heptahydrate.

[0015] A method for preparing a microbial compound fertilizer includes the following steps: S1. Preparation of modified organic carrier: Plant-derived organic matter is crushed, cellulase and protease are added for enzymatic hydrolysis, and then mineral-derived potassium humate and plant growth promoter are added and mixed evenly to obtain modified organic carrier; S2. Core granulation: The inorganic fertilizer matrix, trace element additives and the modified organic carrier obtained in step S1 are mixed in proportion and then subjected to drum granulation or disc granulation to obtain the core of compound fertilizer granules. S3. Drying and cooling: The particle cores obtained in step S2 are dried in a dryer, and the discharge temperature is controlled to be cooled to below 45°C. S4. Microbial agent coating: The compound microbial agent and synergist are mixed to form a suspension, which is then uniformly coated onto the cooled particle core surface by spraying. S5. Screening and Packaging: The coated fertilizer is screened to obtain the microbial compound fertilizer.

[0016] Furthermore, in step S1, the enzymatic hydrolysis process temperature is controlled at 45-55℃, the enzymatic hydrolysis time is 12-24 hours, and the pH value of the material after enzymatic hydrolysis is adjusted to 6.5-7.5. Furthermore, in step S2, an appropriate amount of binder solution is sprayed in during the granulation process. The binder solution is a polyvinyl alcohol solution or molasses waste liquid with a mass concentration of 3%-5%, and the granulation moisture content is 3%-5%.

[0017] Furthermore, in step S3, the air inlet temperature of the dryer is controlled at 150-180℃, the material heating temperature is controlled to not exceed 70℃, and the moisture content of the dried particles is controlled to be below 3.0%.

[0018] Further, step S4 specifically involves: first, dissolving the synergistic agent in film-forming oil to prepare a coating solution, which is then sprayed onto the surface of the granule core to form an inner protective layer; subsequently, in a roller coating machine, negative pressure suction is used to adsorb the powdered compound microbial agent onto the surface of the inner protective layer to form an outer functional layer; the film-forming oil is a liquid wax, and the amount used is 0.5%-1.0% of the weight of the compound fertilizer granule core; the fineness of the compound microbial agent is ≥200 mesh.

[0019] This invention constructs a modified organic carrier using "enzymatically fermented plant-derived organic matter + mineral-derived potassium humate + specific plant growth promoters," addressing the technical problems of traditional carriers such as "slow degradation of macromolecules, poor water and fertilizer retention and microbial microenvironment, decline in bacterial activity during granulation / drying / application, and poor compatibility with inorganic matrices leading to insufficient strength and nutrient loss." Specifically, cellulase / protease enzymatic hydrolysis transforms macromolecules such as cellulose and protein into usable small-molecule carbon and nitrogen sources and porous organic matrices, making nutrient release more aligned with the biological nutrient demand rhythm, while providing a more stable attachment and buffering environment for microorganisms. Potassium humate, with its multifunctional complexation / exchange capabilities, enhances the carrier's fertilizer retention and micronutrient availability, and improves particle-soil interface mass transfer, thereby enhancing the coupling efficiency of "nutrients-microorganisms-rhizosphere." Specific plant growth promoters further promote root vitality and rhizosphere exudate supply, conversely strengthening the colonization and metabolism of beneficial bacteria in the rhizosphere, achieving a positive feedback loop of "promoting roots → increasing exudate → promoting bacteria → further promoting absorption." Building upon this foundation, the inorganic fertilizer matrix provides fast-acting NPK, while the compound microbial agent links the fast-acting and slow-acting processes through phosphorus and potassium solubilization, enzyme secretion, and antagonism. It also works with EDTA to chelate calcium, magnesium, boron, zinc, and other micronutrients to support key physiological responses in crops. Simultaneously, synergistic adjuvants act as amplifiers for water and fertilizer retention, complexation and slow release, and growth induction. Crucially, the process employs core granulation followed by drying and cooling to below 45°C before coating the agent. A liquid wax film forms the inner protective layer, while negative pressure adsorption of the powdered agent forms the outer functional layer. This significantly reduces the damage to the microorganisms caused by heat stress and direct contact with salt / nutrients, ensuring the agent remains highly active on the granule surface.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. By modifying the carrier using the approach of "enzymatically fermented plant-derived organic matter + mineral-derived potassium humate + specific plant growth promoters", the organic components are more easily utilized, and the carrier has a better water and fertilizer retention and buffering environment, thereby improving the problems of slow decomposition, mismatch between fertilizer supply and demand, and weak water and fertilizer retention of traditional carriers.

[0021] 2. The process of "granulation and drying first, followed by cooling and then coating with bacterial agent" is adopted. Through the coating structure of inner protective layer + outer functional layer, the adverse effects of processing and storage on the bacterial cells are reduced, making it easier for the bacterial agent to maintain its activity on the particle surface.

[0022] 3. Inorganic substrates provide fast-acting nutrients, and compound microbial agents, trace elements, and synergistic adjuvants work together to strengthen the linkage between rhizosphere coupling and nutrient transformation and utilization, achieving a more consistent and sustainable comprehensive effect of soil improvement, growth promotion, and quality enhancement. Attached Figure Description

[0023] Figure 1 The image shows the infrared spectrum of the modified organic support prepared in Example 1. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1-1 Preparation of N-(2-(2-(1H-indol-3-yl)acetamido)ethyl)-2-hydroxybenzamide, a plant growth promoter: ; Step A: Add 5.00 g of compound 1-1 and 60 ml of anhydrous dichloromethane to a dry flask, stir until homogeneous, add 5.78 g of HOBt and 8.21 g of EDC·HCl, stir and activate for 30 minutes, add 11.07 g of N,N-diisopropylethylamine and 5.03 g of compound 1-2, stir at room temperature for 15 hours; after the reaction is complete, wash the reaction solution twice with 100 ml of 1M hydrochloric acid aqueous solution, twice with 100 ml of saturated sodium bicarbonate aqueous solution, and once with 100 ml of saturated saline solution, retaining the organic phase; dry the organic phase with anhydrous sodium sulfate for 30 minutes, filter to remove the desiccant, concentrate under reduced pressure to remove the solvent, and obtain the crude product; purify the crude product by silica gel column chromatography, with the eluent gradient being a mixed solvent of petroleum ether and ethyl acetate (PE:EA = 2:1 to 1:1), collect the fraction containing the target product and evaporate to dryness, and then vacuum dry to obtain 6.03 g of compound 1-3; HOBt: 1-Hydroxybenzotriazole; EDC·HCl: 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride; Compound 1-1: Indole-3-acetic acid; Compounds 1-2: tert-butyl(2-aminoethyl)carbamate; Compounds 1-3: tert-butyl(2-(2-(1H-indol-3-yl)acetamido)ethyl)carbamate.

[0026] Structural identification data of compounds 1-3: Mass spectrometry (MS+H) of compounds 1-3 + :318.

[0027] Step B: Add 6.03 g of compounds 1-3 and 60 mL of anhydrous dichloromethane to a dry flask, stir until homogeneous, lower the temperature of the reaction system to 0°C, stir for 10 minutes, slowly add 29.3 mL of trifluoroacetic acid dropwise, with the addition temperature not exceeding 5°C. After the addition is complete, allow the reaction system to naturally warm to room temperature, and continue stirring at this temperature for 3 hours. After the reaction is complete, concentrate the reaction mixture by rotary evaporation under reduced pressure. Redissolve the residue in 100 mL of dichloromethane, and under ice bath cooling, slowly add saturated sodium bicarbonate aqueous solution to adjust the pH to 8-9. Collect the organic phases separately, and extract the aqueous phase twice using a mixed solvent of dichloromethane and isopropanol (dichloromethane to isopropanol volume ratio of 3:1, total 50 mL). Combine all organic phases, wash successively with 50 mL of water and 50 mL of saturated brine, and dry with anhydrous sodium sulfate for 30 minutes. Filter to remove the desiccant, concentrate the filtrate under reduced pressure, and dry under vacuum to obtain 2.94 g of compounds 1-4. Compounds 1-4: N-(2-aminoethyl)-2-(1H-indol-3-yl)acetamide.

[0028] Structural identification data of compounds 1-4: Mass spectrometry (MS+H) of compounds 1-4 + :218.

[0029] Step C: Add 2.06 g of compounds 1-5, 2.74 g of HOBt, 3.89 g of EDC·HCl, and 30 mL of anhydrous N,N-dimethylformamide to a dry flask. Stir until well mixed, then slowly add 5.25 g of N,N-diisopropylethylamine. Activate the mixture at room temperature for 15 minutes. After activation, slowly add 2.94 g of compounds 1-4 to the reaction mixture and continue stirring at room temperature for 16 hours. After the reaction is complete, slowly pour the reaction mixture into 150 mL of semi-saturated brine, stir for 10 minutes, and then use 6... The organic phases were extracted three times with 0 ml of ethyl acetate, and the combined organic phases were washed twice with 50 ml of 10% citric acid aqueous solution, twice with 50 ml of saturated sodium bicarbonate aqueous solution, and once with 50 ml of saturated brine. The organic phases were dried over anhydrous sodium sulfate, filtered to remove the desiccant, and the filtrate was concentrated by rotary evaporation under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography with a mixed solvent of dichloromethane and methanol as the eluent. The fraction containing the target product was collected, the solvent was removed by rotary evaporation, and the product was dried under vacuum to obtain 2.85 g of plant growth promoter. Compounds 1-5 are salicylic acid.

[0030] Mass spectrometry (MS+H) of plant growth promoters + 338; NMR of plant growth promoters 1 HNMR-CDCl3: δ7.49-7.38(m,1H),7.33(s,1H),4.37(s,1H),4.10(t,1H),3.49(d,2H) ,3.45-3.33(m,4H),3.29(s,2H),2.43-2.29(m,2H),2.02(dd,1H),1.81-1.59(m,5H).

[0031] Example 1 Preparation of a microbial compound fertilizer: 1. Raw material composition by weight: Inorganic fertilizer substrate: 45 parts (mixed from urea, monoammonium phosphate, and potassium sulfate in a mass ratio of 1.8:1:1.3); Modified organic carrier: 38 parts (composed of plant-derived organic matter, mineral-derived potassium fulvate (with fulvic acid content ≥50%, potassium oxide content ≥12%, and water-insoluble matter ≤1.0%), and a plant growth promoter, in a mass ratio of 60:35:0.5, wherein the plant growth promoter is N-(2-(2-(1H-indol-3-yl)acetamido)ethyl)-2-hydroxybenzamide, prepared by the method described in Examples 1-1); Compound microbial inoculant: 5 parts (from Bacillus subtilis) Bacillus subtilis gelatinous spore-forming bacteria Paenibacillus mucilaginosus and Trichoderma harzianum Trichoderma harzianum The composition consisted of commercially available common bacterial strains, with an effective viable count ratio of 2.5:1.5:1, and a total effective viable count of 6.2 × 10⁻⁶. 9 CFU / g); Micronutrient additives: 4 parts (made from EDTA chelated calcium, EDTA chelated magnesium, borax, and zinc sulfate heptahydrate mixed in a mass ratio of 1:1:1:1); Synergistic agent: 1 part (made of polyglutamic acid and chitosan oligosaccharide mixed in a mass ratio of 1:1).

[0032] 2. Preparation method: S1. Preparation of modified organic carrier: Corn stalks were selected as the plant-derived organic matter and crushed to a particle size of no more than 2 mm. 60 kg of crushed corn stalks were placed in an enzymatic hydrolysis reactor, and 0.8 kg of cellulase (enzyme activity of 20000 U / g) and 0.5 kg of protease (enzyme activity of 50000 U / g) were added. Then, deionized water was added to adjust the moisture content of the material to 55%, and the enzymatic hydrolysis temperature was controlled at 50℃ for 18 hours. After the enzymatic hydrolysis was completed, 35 kg of mineral-derived potassium humate and 0.5 kg of the above-prepared plant growth promoter were added to the reactor and stirred for 30 minutes. During this period, the pH value of the material was adjusted to 7.0 to obtain the modified organic carrier. S2. Core Granulation: Weigh 45 kg of inorganic fertilizer matrix, 4 kg of trace element additives and 38 kg of modified organic carrier obtained in step S1 according to the above mass ratio, put them into a mixer and mix for 20 minutes until uniform; send the mixed material into a rotary drum granulator, and spray a 4% polyvinyl alcohol solution as a binder into the granulator at the same time, control the granulation moisture content to 4%, adjust the rotary drum speed to 35 r / min, and carry out the granulation operation to obtain the core of compound fertilizer granules; S3. Drying and cooling: The compound fertilizer granules obtained in step S2 are fed into a drum dryer. The inlet air temperature of the dryer is controlled at 165°C. The temperature control device ensures that the material temperature does not exceed 65°C. The granules are dried until the moisture content is 2.5%. The dried granules are then fed into a cooler and cooled using a combination of natural air and forced ventilation. The outlet temperature is controlled at 40°C. S4. Microbial Agent Coating: Weigh 1 kg of synergistic agent and add it to 0.4 kg of liquid wax (0.8% of the core weight of the compound fertilizer granules). Stir and dissolve to prepare a coating solution. Spray the solution evenly onto the cooled granule core surface using a spraying device to form an inner protective layer. Add 5 kg of compound microbial agent (220 mesh fineness) to the roller coating machine. Use a negative pressure suction device to evenly adsorb the powdered agent onto the surface of the inner protective layer to form an outer functional layer. During the coating process, control the roller speed at 25 r / min, the negative pressure value at -0.03 MPa, and the coating time at 15 minutes. S5. Screening and Packaging: The coated fertilizer is fed into a vibrating screen and screened using a double-layer screen with 2.0mm and 4.75mm mesh. Particles in the range of 2.0-4.75mm are collected, which are the microbial compound fertilizer.

[0033] Example 2 The preparation of a microbial compound fertilizer is carried out according to the preparation method of Example 1, except that the mass ratio of urea, monoammonium phosphate and potassium sulfate in the inorganic fertilizer matrix is ​​adjusted to 1.5:1:1.2, and the rest is the same as in Example 1.

[0034] Example 3 The preparation of a microbial compound fertilizer follows the preparation method of Example 1, except that the mass ratio of plant-derived organic matter, mineral-derived potassium humate, and plant growth promoter in the modified organic carrier is adjusted to 68:31:0.9, and the rest remains the same as in Example 1.

[0035] Comparative Example 1 The preparation of a microbial compound fertilizer is carried out according to the preparation method of Example 1, except that the plant growth promoter is replaced with indolebutyric acid (a commonly used artificially synthesized plant growth promoter), and the rest is the same as in Example 1.

[0036] Comparative Example 2 The preparation of a microbial compound fertilizer is carried out according to the preparation method of Example 1, except that the plant growth promoter is replaced with 6-benzylaminopurine (a commonly used synthetic plant growth promoter), and the rest is the same as in Example 1.

[0037] Comparative Example 3 The preparation of a microbial compound fertilizer is the same as in Example 1, except that no plant growth promoter is added.

[0038] Comparative Example 4 The preparation of a microbial compound fertilizer is carried out according to the preparation method of Example 1, except that the modified organic carrier does not undergo an enzymatic hydrolysis step, and the rest is the same as in Example 1.

[0039] Performance testing: Tomato seedlings (four leaves and one heart, transplanting diary day 0) were used as the test crop in a greenhouse pot experiment (plastic pots, filled with 5.0 kg of loam that had passed through a 2 mm sieve; soil pH 6.8, electrical conductivity 0.8 mS / cm, organic matter 18 g / kg, available nitrogen 85 mg / kg, available phosphorus 20 mg / kg, available potassium 120 mg / kg). A blank control group (no fertilizer) was set up. For the other treatments, 0.01 kg / pot (2 g / kg soil) was applied as basal fertilizer and thoroughly mixed with the soil. The same amount (0.01 kg / pot) was applied as top dressing 30 days after transplanting. Each treatment was replicated 3 times. The greenhouse day / night temperature was (25±2) / (18±2)℃, and irrigation and pest and disease management were uniform. When natural light was insufficient, supplemental lighting was provided until the daylight duration was 14 hours. Plant height and stem diameter were measured 60 days after transplanting; harvesting was carried out in batches from 75 days after transplanting to 110 days after transplanting, and the cumulative fruit yield was calculated. The results are shown in Table 1.

[0040] Table 1

[0041] Compared with the control group, all treatments applying microbial compound fertilizer significantly promoted tomato growth and yield. Example 1 showed the best overall effect, with plant height reaching 78 cm and stem diameter 11.5 mm 60 days after transplanting, and a cumulative fruit yield (75-110 days) of 980 g / pot, indicating a superior synergistic effect in nutrient supply and growth promotion. Examples 2 and 3, after adjusting the inorganic fertilizer ratio or modified organic carrier ratio, showed slight decreases in plant height, stem diameter, and yield, but remained close to Example 1 overall, demonstrating the stability of the system. Comparative Examples 1 and 2, while still significantly better than the control group, had lower growth promotion effects and yield levels than the examples, indicating that the specific plant growth promoter of this invention is more beneficial to crop growth than conventional synthetic promoters. In Comparative Examples 3 and 4, the absence of plant growth promoters or enzymatic hydrolysis significantly reduced plant growth and yield, indicating that the enzymatic hydrolysis of plant growth promoters and modified organic carriers plays a crucial role in improving the overall effectiveness of the microbial compound fertilizer.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A microbial compound fertilizer, characterized in that, The raw materials include the following parts by weight: Inorganic fertilizer substrate: 35-55 parts; 30-45 parts of modified organic carrier; 2-8 parts of compound microbial inoculant; 3-6 parts of trace element additives; And 0.5-2 parts of synergistic adjuvants; The modified organic carrier is a mixture of plant-derived organic matter that has undergone enzymatic hydrolysis and fermentation, mineral-derived potassium humate, and plant growth promoters. The plant growth promoter is N-(2-(2-(1H-indol-3-yl)acetamido)ethyl)-2-hydroxybenzamide.

2. The microbial compound fertilizer according to claim 1, characterized in that, The compound microbial agent is composed of Bacillus subtilis. Bacillus subtilis gelatinous spore-forming bacteria Paenibacillus mucilaginosus and Trichoderma harzianum Trichoderma harzianum composition; The effective viable count ratio of Bacillus subtilis, Bacillus mucilaginosus, and Trichoderma harzianum is 2-3:1-2:1; and the total effective viable count of the compound microbial agent is ≥5.0×10⁻⁶. 9 CFU / g.

3. The microbial compound fertilizer according to claim 1, characterized in that, The inorganic fertilizer matrix is ​​composed of urea, monoammonium phosphate, and potassium sulfate in a mass ratio of 1.5-2.0:1:1.2-1.

5.

4. The microbial compound fertilizer according to claim 1, characterized in that, The mass ratio of plant-derived organic matter, mineral-derived potassium humate, and plant growth promoter in the modified organic carrier is 50-70:20-40:0.1-1.

0.

5. A microbial compound fertilizer according to claim 1, characterized in that, The synergistic agent is one or a combination of several of polyglutamic acid, chitosan oligosaccharide, and polyaspartic acid.

6. The microbial compound fertilizer according to claim 1, characterized in that, The trace element additives are one or more of EDTA chelated calcium, EDTA chelated magnesium, borax, and zinc sulfate heptahydrate.

7. A method for preparing a microbial compound fertilizer as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Preparation of modified organic carrier: Plant-derived organic matter is crushed, cellulase and protease are added for enzymatic hydrolysis, and then mineral-derived potassium humate and plant growth promoter are added and mixed evenly to obtain modified organic carrier; S2. Core granulation: The inorganic fertilizer matrix, trace element additives and the modified organic carrier obtained in step S1 are mixed in proportion and then subjected to drum granulation or disc granulation to obtain the core of compound fertilizer granules. S3. Drying and cooling: The particle cores obtained in step S2 are dried in a dryer, and the discharge temperature is controlled to be cooled to below 45°C. S4. Microbial agent coating: The compound microbial agent and synergist are mixed to form a suspension, which is then uniformly coated onto the cooled particle core surface by spraying. S5. Screening and Packaging: The coated fertilizer is screened to obtain the microbial compound fertilizer.

8. The method for preparing a microbial compound fertilizer according to claim 7, characterized in that, In step S1, the enzymatic hydrolysis process is controlled at a temperature of 45-55℃, the hydrolysis time is 12-24 hours, and the pH value of the material after enzymatic hydrolysis is adjusted to 6.5-7.

5.

9. The method for preparing a microbial compound fertilizer according to claim 7, characterized in that, In step S2, an appropriate amount of binder solution is sprayed in during the granulation process. The binder solution is a polyvinyl alcohol solution or molasses waste liquid with a mass concentration of 3%-5%, and the granulation moisture content is 3%-5%.

10. The method for preparing a microbial compound fertilizer according to claim 7, characterized in that, In step S3, the air inlet temperature of the dryer is controlled at 150-180℃, the material heating temperature is controlled not to exceed 70℃, and the moisture content of the dried particles is controlled below 3.0%. Step S4 is specifically operated as follows: First, the synergist is dissolved in the film-forming oil to make a coating solution, which is then sprayed onto the surface of the particle core to form an inner protective layer; then, in the roller coating machine, the powdered composite microbial agent is adsorbed onto the surface of the inner protective layer by negative pressure suction to form an outer functional layer. The film-forming oil is a liquid wax, and its dosage is 0.5%-1.0% of the core weight of the compound fertilizer granules; the fineness of the compound microbial agent is ≥200 mesh.

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