A ralstonia solanacearum bacterial agent, microbial granular fertilizer, preparation method and application thereof

Abstract

The application provides an Acer pseudoplatani Roridinum bacterial agent, a microbial granular fertilizer and a preparation method and application thereof, and relates to the field of microorganisms. Rouxiella aceris The Acer pseudoplatani Roridinum bacterial agent contains the Acer pseudoplatani Roridinum (RA) with the preservation number of CGMCC No.35889, the strain has the ability to decompose inorganic phosphorus, and has a wide range of phosphorus decomposition, can decompose tricalcium phosphate, ferric phosphate and aluminum phosphate, and has a very strong ability to decompose inorganic phosphorus under low temperature conditions; the strain has the ability to produce siderophores and low-temperature IAA; the strain has inhibitory effect on a plurality of pathogenic bacteria causing field crop diseases. The microbial granular fertilizer provided by the application contains a plurality of biological stimulant substances, can promote crop growth, improve plant stress resistance and the resistance of plants to diseases and pests, and field tests prove that the microbial granular fertilizer can significantly promote crop growth and improve crop yield.

Description

Technical Field

[0001] This invention relates to the field of microbiology, specifically to a *Russula natans* inoculant, microbial granular fertilizer, its preparation method, and its application. Background Technology

[0002] In my country's farmland soils, over 95% of phosphorus exists in the form of ineffective phosphorus, such as tricalcium phosphate, ferric phosphate, and aluminum phosphate. This inorganic phosphorus is difficult for crops to directly absorb and utilize, leading to chronic phosphorus deficiency. Traditional agricultural production primarily relies on chemical phosphate fertilizers to alleviate this deficiency. However, chemical phosphate fertilizers have low utilization rates, with most phosphorus being fixed in the soil, failing to provide a continuous supply of phosphorus throughout the crop's growth cycle. Furthermore, excessive phosphate fertilizers can cause soil compaction. Phosphorus-solubilizing microorganisms can decompose insoluble inorganic phosphorus in the soil, sustainably providing absorbable phosphorus to crops and addressing phosphorus deficiency. However, in low-temperature environments, soil microbial activity significantly decreases, and existing phosphorus-solubilizing microbial strains often fail to function properly, unable to effectively activate insoluble inorganic phosphorus in the soil, further exacerbating the phosphorus shortage problem for crops or overwintering crops in low-temperature regions.

[0003] From the perspective of soil phosphorus forms, although tricalcium phosphate is a poorly soluble inorganic phosphorus, its chemical stability is relatively low compared to aluminum phosphate and iron phosphate, which also exist in the soil. Aluminum phosphate and iron phosphate are present in extremely high proportions in typical low-phosphorus soils in my country, such as acidic soils, red soils, and yellow soils. These two types of phosphorus compounds have extremely strong chemical stability and are the most stubborn and difficult-to-decompose inorganic phosphorus forms in the soil. Conventional phosphorus-solubilizing microorganisms cannot decompose iron phosphate and aluminum phosphate, severely limiting their application in improving low-yield fields such as acidic and infertile soils. Indoleacetic acid (IAA) is an important plant growth regulator that effectively promotes root development and cell elongation in crops. Existing IAA-producing microorganisms typically rely on medium- to high-temperature environments; their IAA production efficiency decreases significantly under low-temperature conditions, making it difficult to meet the growth regulator needs of crops in cold regions. Furthermore, frequent crop diseases in field production are a major challenge in agricultural production. Major grain crops such as sorghum, corn, and wheat are frequently attacked by diseases such as root rot and sorghum leaf spot, leading to sharp yield reductions.

[0004] Therefore, in order to improve crop yield and quality, especially for crops grown in low-temperature regions such as high latitudes and high altitudes, or for overwintering crops, there is an urgent need for a multifunctional microbial agent that can decompose inorganic phosphorus at low temperatures, produce IAA at low temperatures, and effectively inhibit various pathogens and promote crop growth.

[0005] In the field of field crop cultivation, corn, wheat, sorghum, and other important food crops are directly related to food security due to their growth status and yield. While the long-term and excessive application of traditional chemical fertilizers has, to some extent, ensured crop yields, it has also brought about many serious problems. On the one hand, chemical fertilizers cause serious pollution to the natural environment, including soil and water sources, leading to the destruction of biodiversity and increasingly prominent problems of soil erosion, acidification, and compaction, seriously threatening the quality and safety of agricultural products. On the other hand, the continuous growth of the global population and the ever-increasing demand for food have led to increasingly strained agricultural production factors such as land and water resources, posing a significant challenge to traditional agricultural production methods. Against this backdrop, microbial fertilizers have attracted considerable attention due to their environmental friendliness and high efficiency.

[0006] Microbial fertilizers, centered on the life activities of microorganisms, provide crops with specific fertilization effects. The beneficial microorganisms in these products demonstrate significant effects in improving soil fertility, refining soil structure, stimulating crop growth and development, enhancing crop quality, strengthening plant disease resistance and stress tolerance, reducing chemical fertilizer use, and increasing fertilizer utilization. Their mechanism of action relies on living microorganisms with specific functions, which directly or indirectly influence plant metabolism through growth, reproduction, and physiological activities. Currently, specialized microbial fertilizers for field crops are relatively scarce, and they struggle to maintain stable colonization and exert their effects of promoting crop growth, enhancing plant stress tolerance, and improving plant resistance to pests and diseases during periods of significant soil temperature fluctuations. This makes it difficult to precisely meet the specific needs of field crops during their growth process, a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is twofold: firstly, to provide a multifunctional microbial agent capable of decomposing inorganic phosphorus at low temperatures, producing IAA at low temperatures, effectively inhibiting various pathogens, and promoting crop growth; and secondly, to provide a microbial fertilizer that can precisely meet the specific needs of field crops during their growth process.

[0008] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a *Russella asiatica* inoculum containing *Russella asiatica* with accession number CGMCC No. 35889. Rouxiella aceris )RA.

[0009] Rhus przewalskii ( Rouxiella aceris RA was deposited on September 11, 2025, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 35889.

[0010] Furthermore, the *Russula natans* inoculant is a solid inoculant or a liquid inoculant.

[0011] Furthermore, the *Russula macrantha* inoculant includes *Russula macrantha* (… Rouxiella aceris RA's fungal sludge and peat powder.

[0012] Secondly, the present invention provides a method for preparing the aforementioned *Russella asiatica* inoculant, comprising the following steps: inoculating the *Russella asiatica* (… Rouxiella aceris The RA fungal mud is adsorbed onto peat powder, dried in the shade, and then sieved to obtain the Maize Rhus rubra inoculant.

[0013] Furthermore, the mass ratio of mycelium raffinis RA to peat powder is 1:3~6.

[0014] Furthermore, the mass ratio of the mycelium sludge and peat powder of *Russula natans* RA is 1:5.

[0015] Furthermore, the inoculum viability of the *Russula natans* inoculum is not less than 4 × 10⁻⁶. 9 CFU / g; Furthermore, the sieve mesh size is 20-60 mesh.

[0016] Furthermore, the sieve mesh size is 20 mesh.

[0017] Furthermore, the method for preparing the mycelial sludge of *Russula natans* RA includes: picking a single colony of *Russula natans* RA and inoculating it into a fermentation medium, culturing it at 20-30 ℃ and 150-200 rpm for 1-2 days, transferring it into the fermentation medium at 5%-20% (v / v) with a sample volume of 100-200 mL / 500 mL, culturing it at 20-30 ℃ and 150-200 rpm for 1-2 days to obtain the fermentation broth, and centrifuging the fermentation broth to obtain the mycelial sludge.

[0018] Furthermore, the method for preparing the mycelial sludge of *Russula natans* RA includes: picking a single colony of *Russula natans* RA and inoculating it into a fermentation medium, culturing it at 28 ℃ and 200 rpm for 1 day, transferring it to the fermentation medium at 10% (v / v) with a sample volume of 100 mL / 500 mL, culturing it at 28 ℃ and 200 rpm for 1 day to obtain the fermentation broth, and centrifuging the fermentation broth to obtain the mycelial sludge.

[0019] Furthermore, the centrifugation conditions were 6000 rpm for 10 min.

[0020] Further, based on the mass of the solvent distilled water, the fermentation medium comprises the following components: 0.3%~0.6% peptone, 0.2%~0.7% yeast extract, 0.04%~0.06% magnesium sulfate, 0.5%~2% brown sugar, and 0.5%~1.5% sodium chloride; the pH value of the fermentation medium is 7.0~7.2.

[0021] Furthermore, based on the mass of the solvent distilled water, the fermentation medium comprises the following components: 0.5% peptone, 0.5% yeast extract, 0.05% magnesium sulfate, 1% brown sugar, and 1% sodium chloride; the pH value of the fermentation medium is 7.0~7.2.

[0022] Thirdly, the present invention provides the application of the aforementioned *Russula macrantha* inoculant or the *Russula macrantha* inoculant prepared by the aforementioned method in the decomposition of inorganic phosphorus in soil, production of indoleacetic acid, production of iron phosphate, inhibition of crop diseases, or promotion of crop growth.

[0023] Furthermore, the decomposition of inorganic phosphorus in the soil is carried out at an ambient temperature of 5~30 ℃ (5, 10, 15, 20, 25, 30 ℃).

[0024] Furthermore, the indoleacetic acid production is carried out at an ambient temperature of 5~30 ℃ (5, 10, 15, 20, 25, 30 ℃).

[0025] Furthermore, the types of crop diseases mentioned are maize root rot, sorghum leaf spot, or wheat root rot.

[0026] Furthermore, the *Russula macrantha* inoculant is used to inhibit at least one of the following pathogens: *Fusarium oxysporum*, *Plasmodium sacchari*, *Fusarium solani*, *Alternaria sacchari*, *Rhizoctonia solani*, and *Cyclocarya granatum*.

[0027] Furthermore, the type of crop includes at least one of corn, sorghum, and wheat.

[0028] Furthermore, the crop is a crop grown in low-temperature regions (ambient temperature 5~15℃, or even 5~10℃) or an overwintering crop.

[0029] Fourthly, the present invention provides a microbial granular fertilizer, comprising, by weight, the following raw material components: 50-70 parts organic fertilizer, 10-15 parts diatomaceous earth, 5-15 parts biochemical potassium humate, 5-10 parts calcium magnesium phosphate fertilizer, 2-3 parts chitosan oligosaccharide, 1-3 parts seaweed extract, 1-2 parts fish protein, 0.1-0.3 parts *Streptomyces cocoa* inoculant, and 5-7 parts *Russula natans* inoculant, wherein the *Streptomyces cocoa* inoculant contains *Streptomyces cocoa* with preservation number CGMCC No. 13080. Streptomyces cacaoi FN, the *Russula natans* inoculum contains *Russula natans* with preservation number CGMCC No. 35889. Rouxiella aceris )RA.

[0030] Streptomyces cocoa ( Streptomyces cacaoiFN was deposited on October 12, 2016, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 13080. This strain has been published in Chinese patent document CN106834193A on June 13, 2017.

[0031] Furthermore, the microbial granular fertilizer, by weight, comprises the following raw material components: 65 parts organic fertilizer, 10 parts diatomaceous earth, 10 parts biochemical potassium humate, 5 parts calcium magnesium phosphate fertilizer, 3 parts chitosan oligosaccharide, 1 part seaweed extract, 1 part fish protein, 0.1 parts Streptomyces cocoa inoculant and 5 parts Rhus chinensis inoculant.

[0032] Furthermore, the activity of Streptomyces cocoa FN in the microbial granular fertilizer is not less than 3.0 × 10⁻⁶. 8 CFU / g, the bacterial activity of *Russula natans* RA is not less than 2.0 × 10⁻⁶ CFU / g. 8 CFU / g.

[0033] Furthermore, the preparation method of the *Streptomyces cocoa* inoculant includes: Preparation of spore suspension: Sterile water was added to the slant of 2216E solid culture medium containing Streptomyces cocoa FN, and then the spores were scraped off. The mixture was shaken to obtain a spore suspension with a cell concentration of 10. 8 ~10 9 CFU / mL; Seed culture: The spore suspension was inoculated into the seed culture medium at an inoculation rate of 1%~3% (v / v) and cultured in a shake flask at 28℃ and 160~240 rpm for 90~100 h to obtain the seed culture. Solid fermentation culture: The seed liquid was inoculated into a solid fermentation medium with a water content of 50% at an inoculation rate of 5%~15% (mL / g), fermented in a tray at 28 ℃ for 3~6 days, air-dried at 20~30 ℃, ground with a pulverizer, and sieved to obtain the Streptomyces cocoa inoculum.

[0034] Furthermore, in the seed culture step, the spore suspension is inoculated into the seed culture medium at an inoculation rate (v / v) of 1% to 1.5%, and cultured in shake flasks at 25 to 30 °C and 180 to 220 rpm for 95 to 98 h to obtain the seed culture.

[0035] Furthermore, in the seed culture step, the spore suspension is inoculated into the seed culture medium at an inoculation rate of 1% (v / v) and cultured in a shake flask at 28 ℃ and 200 rpm for 96 h to obtain the seed culture.

[0036] Further, in the solid fermentation culture step, the seed liquid is inoculated into a solid fermentation culture medium with a water content of 50% at an inoculation amount of 10%~12% (mL / g), and fermented in a tray at 28 ℃ for 4~5 days. From the beginning to the end of the fermentation, the water content of the solid fermentation culture medium is maintained at a constant 50%. During the fermentation, the medium is turned over 2~3 times. After the fermentation is completed, the medium is air-dried at 25~30 ℃, ground with a pulverizer, and the pulverized material that passes through a 20~60 mesh sieve is collected to obtain the Streptomyces cocoa inoculum.

[0037] Further, in the solid fermentation culture step, the seed liquid is inoculated into a solid fermentation culture medium with a water content of 50% at an inoculation amount of 10% (mL / g), and fermented in a tray at 28 ℃ for 4 days. From the beginning to the end of the fermentation, the water content of the solid fermentation culture medium is maintained at a constant 50%. The medium is turned over 3 times during the fermentation. After the fermentation is completed, the medium is air-dried at 28 ℃, ground with a pulverizer, and the pulverized material that passes through a 20-mesh sieve is collected to obtain the Streptomyces cocoa inoculum.

[0038] Furthermore, the viability of the *Streptomyces cocoa* inoculant is not less than 2 × 10⁻⁶. 11 CFU / g.

[0039] Furthermore, the 2216E solid culture medium, per L volume, comprises the following components: 5 g of bacterial peptone No. 2, 1 g of yeast extract, 20 g of agar, with the remainder being distilled water and a natural pH.

[0040] Furthermore, the seed culture medium, per L volume, comprises the following components: 10 g corn flour, 10 g peptone, 5 g yeast powder, 2 g dipotassium hydrogen phosphate, 0.3 g magnesium sulfate, with the remainder being distilled water and a natural pH.

[0041] Furthermore, the solid fermentation medium comprises the following components by mass fraction: 20% rice husk, 44.7% wheat bran, 22% corn flour, 12% soybean meal, 0.8% calcium carbonate, 0.3% dipotassium hydrogen phosphate, 0.2% magnesium sulfate, and natural pH.

[0042] Fifthly, the present invention provides a method for preparing the microbial granular fertilizer, comprising the following steps: mixing raw material components in proportion, crushing, and sieving to obtain crushed material with a particle size of less than 1 mm; adjusting the moisture content of the crushed material to 12%~18%, and sequentially granulating and shaping to obtain particles with a particle size of 2.5~3.5 mm; drying the particles to a moisture content of 9%~12%, and sieving to obtain microbial granular fertilizer with a particle size of 3~4 mm.

[0043] Furthermore, the moisture content of the pulverized material is adjusted to 15%.

[0044] Furthermore, a ring die pellet mill is used for pelleting, with a ring die compression ratio of 1:3.5.

[0045] Further, a particle shaping machine is used for shaping.

[0046] Further, after shaping, particles with a diameter of 3 mm were obtained.

[0047] Furthermore, the drying temperature is 45 ℃ and the drying time is 1 day.

[0048] Further, the granules are dried to a moisture content of 10%.

[0049] Sixthly, the present invention provides the application of the microbial granular fertilizer or the microbial granular fertilizer obtained by the preparation method described above in the planting of field crops.

[0050] Furthermore, the microbial granular fertilizer is applied as a base fertilizer.

[0051] Furthermore, the field crop is at least one of sorghum, corn, and wheat.

[0052] Furthermore, the microbial granular fertilizer is used to promote crop growth or increase crop yield.

[0053] The technical solution provided by this invention has the following advantages: 1. The *Russula macrantha* inoculant provided by this invention contains *Russula macrantha* RA, which has several outstanding effects: First, *Russula macrantha* RA has the ability to decompose inorganic phosphorus, and its phosphorus-solubilizing range is wide, capable of decomposing tricalcium phosphate, ferric phosphate, and aluminum phosphate. Especially under low-temperature conditions, it still has a strong ability to decompose inorganic phosphorus, i.e., it has outstanding low-temperature phosphorus-solubilizing ability: at a low temperature of 5 ℃, it decomposes 321.17 mg / L of tricalcium phosphate, 7.11 mg / L of ferric phosphate, and 5.75 mg / L of aluminum phosphate; at a low temperature of 10 ℃, it decomposes 346.52 mg / L of tricalcium phosphate, 16.75 mg / L of ferric phosphate, and 6.85 mg / L of aluminum phosphate. Second, *Russula macrantha* RA has the ability to produce heparin, which is beneficial for the decomposition of insoluble ferric phosphate. Third, *Russula macrantha* RA has the ability to produce IAA at low temperatures. At the optimal temperature of 15 ℃, its IAA production capacity is 57.38 mg / L, and at a low temperature of 5 ℃... The ability to produce IAA under ℃ conditions is 40.03 mg / L; Fourth, *Rhus aceae* RA has an inhibitory effect on a variety of pathogens that cause diseases in field crops (*Fusarium oxysporum*, *Plasmodium sacchari*, *Fusarium solani*, *Alternaria alternata*, *Rhizoctonia solani*, and *Cyclocarya granatum*), and can inhibit diseases such as corn root rot, sorghum leaf spot, or wheat root rot.

[0054] 2. The microbial granular fertilizer provided by the present invention comprises organic fertilizer, diatomaceous earth, biochemical potassium humate, calcium magnesium phosphate fertilizer, chitosan oligosaccharide, seaweed extract, fish protein, Streptomyces cocoa inoculum and Rhus chinensis inoculum.

[0055] *Rhus aceae* RA can colonize in soil environments ranging from 5 to 40 ℃, with the strongest colonization ability at 20 ℃. *Streptomyces cocoa* FN can colonize in soil environments ranging from 20 to 50 ℃, with the strongest colonization ability at 30 ℃. Crops experience different soil temperatures throughout their growth cycle. The different colonization abilities of these two functional bacteria at different soil temperatures complement each other, ensuring that the microbial granular fertilizer can function effectively at various soil temperatures.

[0056] Microbial granular fertilizer contains a variety of biostimulants (such as auxin, gibberellin, salicylic acid, brassinosteroids, cytokinins, and jasmonic acid), which can promote crop growth, improve plant stress resistance, and enhance plant resistance to diseases and pests. Field trials have proven that microbial granular fertilizer can significantly promote crop growth and increase crop yield.

[0057] The cocoa streptomyces FN added to the formula has an inhibitory effect on a variety of pathogens that cause diseases in field crops (such as Fusarium graminearum, Fusarium graminearum, Fusarium graminearum, Fusarium graminearum, Rhizoctonia graminearum, Fusarium graminearum, Fusarium graminearum, Fusarium graminearum, Fusarium graminearum, Fusarium graminearum, Alternaria alternata, Alternaria alternata, Alternaria alternata, etc.). It can inhibit the occurrence of field crop diseases such as wheat scab, wheat root rot, wheat sheath blight, wheat stem base rot, maize large leaf spot, maize stem base rot, sorghum stem base rot, sorghum Alternaria alternata leaf spot, and sorghum target spot. Moreover, cocoa streptomyces FN has excellent characteristics such as genetic stability, broad-spectrum antibacterial activity, heat resistance, acid and alkali resistance, and UV radiation resistance. It can be added to microbial granular fertilizer as a biocontrol agent for the prevention and control of field crop diseases.

[0058] 3. The microbial granular fertilizer preparation process provided by this invention is advanced. It ensures the maximum retention of active ingredients such as microorganisms through a gentle granulation process, while also meeting the fertilization requirements of modern facility agriculture. Attached Figure Description

[0059] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0060] Figure 1This is the phylogenetic tree of Rhus erythromycosis RA provided by the present invention; Figure 2 This is a colony morphology diagram of *Russula natans* RA provided by the present invention; Figure 3 This is a microscopic image of the cell morphology of *Russula natans* RA provided by the present invention. Figure 4 This is a graph showing the ability of *Russula natans* RA to produce ferophiles, provided by this invention. Figure 5 This is a picture of the microbial granular fertilizer provided by the present invention. Detailed Implementation

[0061] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0062] The culture media and their composition or preparation methods involved in the examples are as follows: Buffered nutrient medium: 2.5 g yeast extract, 2.5 g bacteriological peptone (Oxoid brand LP0037), 2.5 g glucose, 7.5 g piperazine-1,4-diethanesulfonic acid (PIPES), 1 L distilled water, pH 7.0~7.2.

[0063] Buffered nutrient agar plate: 2.5 g yeast extract, 2.5 g bacteriological peptone (Oxoid brand LP0037), 2.5 g glucose, 7.5 g piperazine-1,4-diethanesulfonic acid (PIPES), 20 g agar, 1 L distilled water, pH 7.0~7.2.

[0064] NA liquid culture medium: 10 g peptone, 3 g beef extract, 5 g sodium chloride, 1 L distilled water, pH 7.0-7.2.

[0065] Meng Jinna's Inorganic Phosphorus Plate Culture Medium: 10g glucose, 0.5g (NH4)2SO4, 0.3g NaCl, 0.3g KCl, 0.3g MgSO4·7H2O, 0.03g FeSO4·7H2O, 0.03g MnSO4·4H2O, 5g Ca3(PO4)2, 20g agar, 1L water, pH 7.0-7.2, sterilized at 115℃ for 20min.

[0066] NB medium: 10 g peptone, 3 g beef extract, 5 g sodium chloride, 1 L distilled water.

[0067] Meng Jinna's Inorganic Phosphorus Liquid Culture Medium: 10 g glucose, 0.5 g (NH4)2SO4, 0.3 g NaCl, 0.3 g KCl, 0.3 g MgSO4·7H2O, 0.03 g FeSO4·7H2O, 0.03 g MnSO4·4H2O, 5 g Ca3(PO4)2 / AlPO4 / FePO4, 1 L water, pH 7.0~7.2, sterilized at 115 ℃ for 20 min.

[0068] Detection medium for ferrophosphate production: (1) 60.5 mg of CAS chromaine dissolved in 50 mL of water; (2) 10 mL of 10 mmol / L FeCl3 solution (containing 10 mmol / L HCl); (3) 72.9 mg of hexadecyltrimethylammonium bromide (HDTMA) dissolved in 40 mL of water; (4) 750 mL of water + 100 mL of salt solution (3 g KH2PO4 + 5 g NaCl + 10 g NH4Cl to 100 mL of water) + 20 g agar + 30.24 g PIPES, with pH adjusted to 6.8 using NaOH; (5) 30 mL of 10% acid hydrolyzed casein solution; (6) 10 mL of 20% glucose solution. Mix (1) and (2) thoroughly and add them to (3) while stirring. Sterilize (3), (4), (5), and (6) separately at 115℃ for 20 min. After sterilization, cool to 50℃ and add (5) and (6) to (4) first, then slowly add (3) to the plate.

[0069] PDA medium: 200 g potato, 20 g glucose, 15 g agar, 1 L distilled water, boiled, filtered, dissolved and dispensed, then autoclaved at 121 °C for 30 min.

[0070] Fermentation medium (using distilled water as solvent, the following percentages are the mass ratio of components to distilled water): peptone 0.5%, yeast extract 0.5%, magnesium sulfate 0.05%, brown sugar 1%, sodium chloride 1%, pH 7.0~7.2.

[0071] 2216E solid culture medium: bacterial peptone No. 2 5 g / L, yeast extract 1 g / L, agar 20 g / L, balance distilled water, pH natural.

[0072] Seed culture medium: corn flour 10 g / L, peptone 10 g / L, yeast extract 5 g / L, dipotassium hydrogen phosphate 2 g / L, magnesium sulfate 0.3 g / L, with the remainder being distilled water, pH at rest.

[0073] Solid fermentation medium: 20% rice husk, 44.7% wheat bran, 22% corn flour, 12% soybean meal, 0.8% calcium carbonate, 0.3% dipotassium hydrogen phosphate, 0.2% magnesium sulfate, pH natural.

[0074] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. All raw materials or instruments used are commercially available conventional products, including but not limited to those used in the embodiments of this application.

[0075] Example 1: Screening of phosphate-solubilizing bacteria Soil samples were collected from Changli County, Qinhuangdao City, with corn as the previous crop. 10 g of soil sample was added to an Erlenmeyer flask containing 100 mL of sterile water and glass beads, shaken at 200 rpm for 30 min, and then serially diluted. 10 g samples were then selected. -5 10 -6 10 -7 10 -8 The diluted solution was spread onto buffered nutrient medium plates and incubated at 28 °C for 3 days. Single colonies of different morphologies were picked and incubated on buffered nutrient medium plates for another 3 days at 28 °C. A total of 15 bacterial strains were isolated. The 16S rDNA of these 15 bacterial strains was amplified, and the amplified fragments were mailed to BGI Genomics for sequencing. The obtained 16S rDNA sequences were compared with BLAST on the NCBI website, and the identification results are shown in Table 1.

[0076] Fifteen isolated bacterial strains were inoculated into NA liquid medium and cultured at 28 ℃ and 200 rpm for 2 days. Wells were then punched on Munkina inorganic phosphate plates using a φ7 mm punch, and 30 μL of the fermentation broth from each of the 15 bacterial strains was inoculated into the wells of the Munkina inorganic phosphate plates. The plates were cultured at 28 ℃ for 7 days, and the width of the zona pellucida was measured. A wider zona pellucida indicates a better phosphate-solubilizing effect of the strain. The phosphate-solubilizing abilities of the 15 bacterial strains are shown in Table 1. It is evident that strain RA exhibits the most outstanding phosphate-solubilizing ability, with a zona pellucida width of 6.0 mm.

[0077] Table 1. Identification results and phosphorus solubilization capacity of 15 bacteria isolated from soil.

[0078] Example 2 Identification of strain RA Bacterial cells of strain RA were collected, and genomic DNA was extracted using a Trans Genomic DNA Extraction Kit. 16S rDNA was amplified using a PCR system consisting of: 5 μl 10× buffer, 1 μl dNTPs, 1 μl 27F, 1 μl 1492R, and 0.5 μl Taq enzyme. Primers for 27F were: 5'-AGA GTT TGA TCC TGG CTCA-3'; primers for 1492R were: 5'-GGT TACCTT GTT ACG ACTT-3'. PCR conditions were: 94 ℃ for 4 min, 94 ℃ for 30 s, 60 ℃ for 30 s, 72 ℃ for 30 s, with a final extension at 72 ℃ for 10 min. The PCR products were ligated into the Trans pEASY-T3 vector, transformed into *E. coli* T1 competent cells, and positive clones were screened and sent to Beijing Liuhe BGI Genomics Co., Ltd. for sequencing.

[0079] The 16S rDNA sequence of strain RA was compared with BLAST on the NCBI website, and the result was *Russula maculata*. Rouxiella aceris The homology was 99.53%.

[0080] The 16S rDNA sequence is shown in SEQ ID No. 1 of the sequence listing: Phylogenetic trees were constructed using MEGA software, based on 16S rDNA sequences, using the Neighbour-Joining method with a Btoostrap value of 1000. The phylogenetic trees are shown below. Figure 1 As shown, strain RA and Rouxiella aceris The strain was named *Russula maculatus* because it is most closely related to the bacteria. Rouxiella aceris RA.

[0081] Acer rumeniae Rouxiella aceris RA has been deposited at the China General Microbiological Culture Collection Center (CGMCC), a depository designated by the State Intellectual Property Office. The address of the depository is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is September 11, 2025, and the deposit number is CGMCC No. 35889.

[0082] The colony morphology of *Russula maculata* RA grown on buffered nutrient agar plates is as follows: Figure 2 As shown, the colonies are white and translucent. The morphology of the bacteria is observed under an optical microscope (10×100x). Figure 3 As shown, the bacterial cells are short rod-shaped.

[0083] Example 3: Physiological and biochemical characteristics of Rhus erythromycosis RA Physiological and biochemical identification of *Russula natans* RA was performed with reference to the relevant contents of *Manual of Systematic Identification of Common Bacteria* and *Bergey's Manual of Bacterial Identification (8th Edition)*. The results are shown in Table 2.

[0084] Table 2. Physiological and biochemical characteristics of Rhus erythromycosis RA

[0085] Example 4: Growth characteristics of Rhus rubrum RA (a type of bacterium) I. Experimental Methods 1. Growth temperature A suspension of *Russella maculata* RA was inoculated at 1‰ onto buffered nutrient medium and incubated for 1 day at 5 ℃, 10 ℃, 20 ℃, 25 ℃, 28 ℃, 30 ℃, 40 ℃, and 45 ℃ on a shaker at 200 rpm. Each treatment was repeated in triplicate, and OD values ​​were measured. 600nm Absorbance value.

[0086] 2. Salt tolerance A suspension of *Russella maculata* RA was inoculated at 1‰ into buffered nutrient media with different salt concentrations. The sodium chloride concentrations were adjusted to 0%, 1%, 2%, 3%, 5%, and 6%, respectively. Each treatment was repeated in triplicate. The cultures were incubated at 28 °C and 200 rpm for 2 days, and the OD was measured. 600nm Absorbance value.

[0087] 3. Acid and alkali resistance A suspension of *Russella maculata* RA was inoculated at 1‰ into NB medium at different pH values. The pH was adjusted to 4, 5, 6, 7, 8, 9, 10, 11, and 12, with three replicates for each treatment. The cultures were incubated at 28 ℃ and 200 rpm for 2 days, and the OD values ​​were measured. 600nm Absorbance value.

[0088] Preparation method of *Russella maculata* RA bacterial suspension: *Russella maculata* RA was inoculated into buffered nutrient medium and cultured at 28℃ and 200 rpm for 1 day. The bacterial cells were collected by centrifugation at 6000 rpm, washed three times with physiological saline, and then added to prepare a bacterial suspension with a viability of 1×10⁻⁶. 8 CFU / mL.

[0089] II. Experimental Results The experimental results of the growth characteristics of Rhus erythromycosis RA are shown in Tables 3-5. The data are expressed as mean ± standard deviation.

[0090] Table 3. Growth temperature range of *Rhus erythrophagus* RA

[0091] Table 4. Salt tolerance range of *Russula natans* RA

[0092] Table 5. pH range of acid and alkali tolerance for *Russula natans* RA

[0093] As shown in Table 3, the growth temperature range of Rhus erythromycosis RA is 5~40 ℃, and the optimal growth temperature is 28 ℃.

[0094] As shown in Table 4, the salt tolerance range of *Russula natans* RA is 0% to 5%, with an optimal salt concentration of 1%.

[0095] As shown in Table 5, the pH range of acid and alkali tolerance of *Russula natans* RA is 5-11, with an optimal pH of 7.0.

[0096] Example 5: Ability of *Russula natans* RA to decompose inorganic phosphorus I. Experimental Methods Preparation of molybdenum antimony sulfate stock solution: Prepare solution A: Weigh 0.5 g of potassium antimony tartrate and dissolve it in 100 mL of water; Prepare solution B: Weigh 10 g of ammonium molybdate and dissolve it in 450 mL of water, slowly add 153 mL of concentrated H2SO4 while stirring; Add solution A to solution B, and finally add water to 1 L, shake well, and store in a brown bottle.

[0097] Preparation of molybdenum-antimony anti-colorimetric reagent: Add 1.50 g of levozyscic acid to 100 mL of molybdenum-antimony sulfate stock solution. This reagent is effective for 24 hours and should be prepared before use.

[0098] Preparation of phosphorus standard stock solution: Accurately weigh 0.2195 g of potassium dihydrogen phosphate dried at 105 ℃ for 2 h, dissolve it in distilled water, add 5 mL of sulfuric acid solution (ρ=1.84 g / mL), cool and standardize to 1000 mL to obtain a phosphorus standard stock solution with a phosphorus (P) concentration of 50 mg / L.

[0099] Determination of phosphorus standard curve: Pipette 0, 200, 400, 600, 800, and 1000 μL of 50 mg / L phosphorus standard stock solution into 50 mL volumetric flasks, corresponding to concentrations of 0, 0.2, 0.4, 0.6, 0.8, and 1 mg / L, respectively. Add 5 mL of molybdenum-antimony anti-chromic reagent, and dilute to 50 mL with ddH₂O. Shake well, let stand for 30 min, and measure the absorbance at 660 nm. Plot the standard curve with concentration on the x-axis and the corresponding measured absorbance on the y-axis.

[0100] *Russula maculata* RA was inoculated into buffered nutrient medium and cultured at 28 ℃ and 200 rpm for 1 day. The bacterial cells were collected by centrifugation at 6000 rpm, washed three times with physiological saline, and then a bacterial suspension was prepared by adding physiological saline (1×10⁻⁶ viable cells). 8 CFU / mL was inoculated at 1% into Mengjina inorganic phosphorus liquid medium and cultured at 28 ℃ with shaking at 200 rpm. The bacterial culture was collected at 7 days and 14 days, centrifuged at 10000 rpm for 10 min, and the supernatant was retained. The supernatant was diluted 50-500 times, 5 mL of molybdenum antimony colorimetric reagent was added, and ddH2O was added to bring the volume to 50 mL. The mixture was shaken well, allowed to stand for 30 min, and the absorbance was measured at 660 nm. The phosphorus concentration was determined according to the phosphorus standard curve. Uninoculated Mengjina inorganic phosphorus liquid medium was used as a blank control.

[0101] II. Experimental Results The ability of *Rhus aceae* RA to decompose inorganic phosphorus is shown in Table 6.

[0102] Table 6. Ability of *Rhus erythrozoae* RA to decompose inorganic phosphorus (unit: mg / L)

[0103] As shown in Table 6, *Russella maculata* RA has the ability to decompose tricalcium phosphate, ferric phosphate, and aluminum phosphate. At the optimum temperature of 15 ℃, it decomposes 363.30 mg / L of tricalcium phosphate, 35.91 mg / L of ferric phosphate, and 9.75 mg / L of aluminum phosphate. *Russella maculata* RA also exhibits a strong ability to decompose inorganic phosphorus at low temperatures. At 5 ℃, it decomposes 321.17 mg / L of tricalcium phosphate, 7.11 mg / L of ferric phosphate, and 5.75 mg / L of aluminum phosphate. At 10 ℃, it decomposes 346.52 mg / L of tricalcium phosphate, 16.75 mg / L of ferric phosphate, and 6.85 mg / L of aluminum phosphate.

[0104] *Russula maculata* has the strongest ability to decompose tricalcium phosphate, followed by ferric phosphate, and then aluminum phosphate. Generally, the ease with which microorganisms decompose different inorganic phosphorus compounds, from most difficult to easiest, is tricalcium phosphate, aluminum phosphate, and then ferric phosphate. *Russula maculata*'s ability to decompose ferric phosphate is stronger than that of aluminum phosphate, which may be related to the fact that this bacterium can produce heparin, which facilitates the decomposition of insoluble ferric phosphate.

[0105] Example 6: Ability of *Rhus erythromycosis* RA to produce heptaphilin I. Experimental Methods Streak *Rhus aceae* RA onto a buffer nutrient medium plate and grow at 28 °C for 1 day. Single colonies from the plate are picked and transferred to a ferophile production test medium plate and incubated at 28 °C for 3 days. The colony diameter (d) and the diameter of the ferophile zone (D) are measured, and the D / d value represents the ferophile production capacity of the strain.

[0106] II. Experimental Results like Figure 4 As shown, *Russula natans* RA has the ability to produce hematophiles, with a D / d value of 2.5.

[0107] Example 7: IAA production capacity of *Rutella maculata* RA I. Experimental Methods Rhus erythromycosis RA was administered at a dose of 1×10 6 CFU / mL of bacteria were inoculated into buffered nutrient medium containing 500 mg / mL L-tryptophan and cultured at 200 rpm for 2 days at 5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, and 30 ℃, respectively. The IAA content was determined by the Salkowski method.

[0108] II. Experimental Results The ability of *Rhus aceae* RA to produce IAA is shown in Table 7.

[0109] Table 7. IAA production capacity of *Russula natans* RA (unit: mg / L)

[0110] As shown in Table 7, the ability to synthesize IAA at the optimal temperature of 15 ℃ is 57.38 mg / L, and the ability to synthesize IAA at a low temperature of 5 ℃ is 40.03 mg / L, which means that *Russula natans* RA has the ability to produce IAA at low temperatures.

[0111] Example 8: Antibacterial activity of Rhus erythromycosis RA I. Experimental Methods A cross was drawn on the back of a 90 mm diameter agar plate, with the intersection of the cross as the center of the plate. 7 mm mycelial discs of pathogens (Fusarium oxysporum, Epicorioides sacchariformis, Fusarium solani, Alternaria sacchariformis, Rhizoctonia solani, and Coelophyte gracilis) were inoculated into the center of the PDA plate. Rhus oryzae RA cells were then inoculated 20 mm from the center of the plate as the treatment group. The control group consisted of no Rhus oryzae RA inoculation. The plates were incubated at 28 ℃ for 7 days. The pathogen radii in the control and treatment groups were measured, and the inhibition rate was calculated.

[0112] Inhibition rate % = (radius of pathogens in control group - radius of pathogens in treatment group) / radius of pathogens in control group × 100%.

[0113] II. Experimental Results The inhibition rates of *Russula natans* RA against the above six pathogens are shown in Table 8.

[0114] Table 8. Inhibition rate of *Rhus aceae* RA against 6 pathogens.

[0115] As shown in Table 8, *Russula natans* RA has an inhibitory effect on a variety of pathogens that cause diseases in field crops (corn root rot, sorghum leaf spot, and wheat root rot).

[0116] Example 9: Antibacterial activity of Streptomyces cocoa FN I. Experimental Methods A cross was drawn on the back of a 90 mm diameter agar plate, with the intersection of the cross as the center of the plate. A 7 mm mycelial disc of pathogens (Fusarium graminearum, Helicobacter pylori, Coelophyte graminearum, Fusarium oxysporum, Helicobacter pylori, Rhizoctonia graminearum, Fusarium pseudograminearum, Fusarium moniliforme, Fusarium moniliforme, Alternaria alternata, Alternaria sorghum, Helicobacter spp.) was inoculated into the center of the PDA agar plate. A Streptomyces cocovenenans FN cell was then inoculated 20 mm from the center as the treatment group. The treatment without Streptomyces cocovenenans FN served as the control. The plates were incubated at 28 ℃ for 7 days. The pathogen radii in the control group and the treatment group were measured, and the inhibition rate was calculated.

[0117] Inhibition rate % = (radius of pathogens in control group - radius of pathogens in treatment group) / radius of pathogens in control group × 100%.

[0118] II. Experimental Results The inhibition rates of Streptomyces cocoa FN against the above 12 pathogens are shown in Table 9.

[0119] Table 9. Inhibition rate of Streptomyces cocoa FN against pathogens of field crop diseases

[0120] As shown in Table 9, Streptomyces cocoa FN has an inhibitory effect on a variety of pathogens that cause diseases in field crops (wheat scab, wheat root rot, wheat sheath blight, wheat stem base rot, maize leaf spot, maize stem base rot, sorghum stem base rot, sorghum Alternaria leaf spot, and sorghum target spot).

[0121] Example 10 Preparation of *Russula natans* inoculant Single colonies of *Russella macrantha* RA were inoculated into fermentation medium and cultured at 28 ℃ and 200 rpm for 1 day. The inoculum was then transferred at a rate of 10% (v / v) to the fermentation medium (100 mL / 500 mL), and cultured at 28 ℃ and 200 rpm for another 1 day to obtain the *Russella macrantha* RA fermentation broth. The fermentation broth was centrifuged at 6000 rpm for 10 min to obtain mycelial sludge. The mycelial sludge was adsorbed onto peat moss powder at a mass ratio of 1:5, air-dried, and then passed through a 20-mesh sieve to obtain *Russella macrantha* inoculum, with a viability of 4 × 10⁻⁶. 9 CFU / g.

[0122] Example 11 Preparation of Streptomyces cocoa inoculum Preparation of spore suspension: Sterile water was added to the slant of 2216E solid medium containing Streptomyces cocoa FN, and the spores were scraped off. The mixture was then shaken to obtain a spore suspension (cell concentration of 1×10⁻⁶). 8 (CFU / mL) Seed culture: The spore suspension was inoculated into the seed culture medium at an inoculation rate of 1% (v / v) and cultured in a shake flask at 28 ℃ and 200 rpm for 96 h to obtain the seed culture. Solid-state fermentation culture: The seed culture was inoculated into a solid-state fermentation medium with a moisture content of 50% at an inoculation rate of 10% (mL / g). Fermentation was carried out in a tray at 28 ℃ for 4 days. From the start to the end of fermentation, the moisture content of the solid-state fermentation medium was maintained at a constant 50%. The medium was turned over 3 times during fermentation. After fermentation, the medium was air-dried at 28 ℃, ground using a grinder, and the pulverized material passing through a 20-mesh sieve was collected to obtain the *Streptomyces cocoa* inoculum, with a viability of 1×10⁻⁶. 11 CFU / g.

[0123] Example 12 Colonization ability of *Rhus aceae* RA and *Streptomyces cocovenenans* FN in soil I. Experimental Methods 0.5% of *Rhus aceae* inoculum (prepared in Example 10) and 0.01% of *Streptomyces cocovenenans* inoculum (prepared in Example 11) were added to sterilized field soil (sampling location: Changli County, Qinhuangdao City). Sterile water was added to adjust the soil moisture to 35%, and the initial *Rhus aceae* RA activity was determined to be 3.41 × 10⁻⁶. 7 CFU / g, the initial bacterial activity of Streptomyces cocoa FN was 2.53 × 10⁻⁶. 7 CFU / g. Field soil was placed in incubators at 5 ℃, 10 ℃, 15 ℃, 20 ℃, 30 ℃ and 40 ℃, and samples were taken at 7 d, 20 d and 30 d to determine the bacterial activity of *Rhus aceae* RA and *Streptomyces cocoa* FN in the field soil.

[0124] II. Experimental Results The colonization capacity of *Rhus aceae* RA and *Streptomyces cocovenenans* FN in soil is shown in Table 10.

[0125] Table 10. Colonization capacity of functional bacteria in field soil at different temperatures (unit: CFU / g)

[0126] As shown in Table 10, *Russula natans* RA can colonize in soil environments ranging from 5 to 40 °C, with the strongest colonization ability at 20 °C; *Streptomyces cocoa* FN can colonize in environments ranging from 20 to 50 °C, with the strongest colonization ability at 30 °C. Crops experience different soil temperatures throughout their growth cycle. The different colonization abilities of these two functional bacteria at different soil temperatures complement each other, ensuring that the microbial granular fertilizer for field crops can function effectively at various soil temperatures.

[0127] Example 13 Preparation of Microbial Granular Fertilizer The microbial granular fertilizer consists of: 65 parts organic fertilizer, 10 parts diatomaceous earth, 10 parts biochemical potassium humate, 5 parts calcium magnesium phosphate fertilizer, 3 parts chitosan oligosaccharide, 1 part seaweed extract, 1 part fish protein, 5 parts *Rhus chinensis* inoculant (prepared in Example 10), and 0.1 parts *Streptomyces cocoa* inoculant (prepared in Example 11).

[0128] The organic fertilizer is an organic fertilizer product produced by Shaanxi Fengdan Baili Biotechnology Co., Ltd., with registration certificate number: Shaanxi Agricultural Fertilizer (2017) Approval No. 1820.

[0129] Diatomite was purchased from Jilin Yuantong Mining Co., Ltd.; biochemical potassium humate was purchased from Guangxi Danbaoli Yeast Co., Ltd.; calcium magnesium phosphate fertilizer was purchased from Hubei Jiduosu Ecological Agriculture Technology Co., Ltd.; chitosan oligosaccharide was purchased from Shandong Haiyihua Biotechnology Co., Ltd.; seaweed extract was purchased from Qingdao Mingyue Seaweed Group Co., Ltd.; and fish protein was purchased from Weihai Hongde Marine Biology.

[0130] The preparation steps of microbial granular fertilizer are as follows: Weigh all the raw materials in the above formula and mix them evenly. Crush the mixed materials using a two-stage wet pulverizer (Gongyi Huashengming Heavy Industry Machinery Factory, model HSM-600), and sieve them using a 20-mesh screen, retaining materials with a particle size of less than 1 mm. Adjust the material moisture to 15%, and prepare granular fertilizer using a ring die pellet mill (Liyang Jufeng Machinery Co., Ltd., model MZL508). Adjust the ring die compression ratio to 1:3.5, and then correct it to a particle size of 3 mm using a pellet shaping machine (Jingmen Zhiyuan Environmental Protection Equipment Co., Ltd., model ZYZY-1200). Dry the prepared granular fertilizer at 45 ℃ for 1 day until the moisture content drops to 10%. After drying, sieve the granular fertilizer through a 3 mm diameter screen, retaining particles with a diameter of 3-4 mm. Figure 5 As shown, the final product is a microbial granular fertilizer with intact particles and uniform pore size.

[0131] The activity of Streptomyces cocoa FN in the microbial granular fertilizer was tested to be 3.0 × 10⁻⁶. 8 CFU / g, *Russula natans* RA activity was 2.0 × 10⁻⁶. 8 CFU / g.

[0132] Example 14: Biostimulant Content in Microbial Granular Fertilizer I. Experimental Methods The content of biostimulants in the microbial granular fertilizer prepared in Example 13 was analyzed using UHPLC-MS / MS. The microbial granular fertilizer was ground in liquid nitrogen. 25 mg of the ground sample was weighed, and 1000 μL of extraction buffer was added. The mixture was vortexed for 60 s, sonicated in an ice-water bath for 10 min, and allowed to stand at -40 ℃ for 2 h. The mixture was then centrifuged at 12000 rpm and 4 ℃ for 15 min. 900 μL of the supernatant was collected and evaporated to dryness at 4 ℃. 90 μL of 50% methanol-water solution was added, and the mixture was vortexed for 1 min, sonicated for 120 s, and then vortexed again for 1 min. The mixture was centrifuged at 12000 rpm and 4 ℃ for 10 min. 80 μL of the supernatant was collected and centrifuged again. 70 μL of the supernatant was then used for analysis.

[0133] The target compounds were separated chromatographically using an ExionLC™ AD UHPLC System (SCIEX) with a UPLCKinetex C18 column (2.1 mm × 100 mm, 2.6 μm, USA). Phase A of the liquid chromatography was 0.1% formic acid in water, and phase B was 0.1% formic acid in methanol. The column oven temperature was 25 °C, the sample pan was set to 4 °C, and the injection volume was 2 μL. A 6500 QTRAP+ triple quadrupole mass spectrometer was used with an ESI electrospray ionization source in multiple reaction monitoring (MRM) mode. The ion source parameters were as follows: ion spray voltage = ±4500 V, ion source gas 1 = 50 psi, ion source gas 2 = 50 psi, ion source temperature = 450 °C, and curtain gas (+ / -) = 40 / 35 psi.

[0134] Extraction solution: 80% methanol aqueous solution, with a concentration of 2 ng / mL for the isotope internal standard mixture.

[0135] II. Experimental Results The content and function of biostimulants in microbial granular fertilizer are shown in Table 11.

[0136] Table 11. Content of biostimulants in microbial granular fertilizer (unit: nmol / g)

[0137] As shown in Table 11, microbial granular fertilizer contains a variety of biostimulants that can promote crop growth, improve plant stress resistance, and enhance plant resistance to diseases and pests.

[0138] Example 15: Field application effect of microbial granular fertilizer I. Experimental Methods The microbial granular fertilizer prepared using Example 13 (Streptomyces cocoa FN activity 3.0 × 10⁻⁶) 8 CFU / g, *Russula natans* RA activity was 2.0 × 10⁻⁶. 8 A field trial of maize was conducted using CFU / g (experimental location: Peijiabao Village, Dapuhe Town, Changli County, Qinhuangdao City; experimental period: June 13, 2024 – October 7, 2024). The experimental field consisted of granite-type residual colluvial brown soil with a pH of 7.9, organic matter of 1.97%, total nitrogen of 0.14%, total phosphorus of 0.27%, and total potassium of 0.39%, of which available phosphorus was 15.3 mg / kg and available potassium was 95 mg / kg. The tested crop was Zhengdan 958 maize. The experiment consisted of 3 treatments with 4 replicates, using a completely randomized block design. Each plot was 10.00 m × 5.50 m = 55.00 m². 2Row spacing is 25 cm and plant spacing is 30 cm. Field management is the same as local routine practices, and microbial granular fertilizer is applied as base fertilizer.

[0139] Treatment 1: 2.5 kg / mu of microbial granular fertilizer + conventional fertilization Treatment 2: 5 kg / mu of microbial granular fertilizer + conventional fertilization Treatment 3: Conventional fertilization Conventional fertilization: On June 13, 2024, 50 kg / mu of compound fertilizer (15-15-15) was applied as base fertilizer. The land was prepared, ridges were made, and seeds were sown in furrows and thoroughly watered. Seedlings emerged on June 20, and thinning was carried out on July 5. Watering was carried out as needed according to soil moisture during this period. Weeding and cultivation were carried out three times throughout the growing season. The corn in the experimental area was harvested on October 7.

[0140] Microbial granular fertilizer was applied as base fertilizer on June 13, 2024.

[0141] The yield of each plot was statistically analyzed, and the data were analyzed using Duncan's new multiple range test in DPS software.

[0142] II. Experimental Results The results of the field trials are shown in Table 12.

[0143] Table 12 Corn Plot Yield Statistics

[0144] As shown in Table 12, treatment 2 (5 kg / mu of microbial granular fertilizer) was significantly better than the other treatments, with a yield increase of 9.40% compared to treatment 3 (conventional fertilization), and treatment 1 (2.5 kg / mu of microbial granular fertilizer) had a yield increase of 6.93% compared to treatment 3 (conventional fertilization). It is evident that the microbial granular fertilizer provided by this invention can significantly promote crop growth and increase crop yield.

[0145] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A type of maple rhubarb ( Rouxiella aceris The bacterial agent is characterized in that, Contains *Russula natans* RA with accession number CGMCC No. 35889.

2. The method for preparing the *Russula natans* inoculant according to claim 1, characterized in that, Includes the following steps: The sludge of *Russula natans* RA was adsorbed onto peat powder, dried in the shade, and then sieved to obtain *Russula natans* inoculum.

3. The method for preparing the *Russula natans* inoculant according to claim 2, characterized in that, The mass ratio of mycelium raffinis RA to peat powder is 1:3~6; The viability of the *Russula macrantha* inoculant is not less than 4 × 10⁻⁶. 9 CFU / g; The sieve mesh size is 20-60 mesh; The method for preparing mycelial sludge of *Russula natans* RA includes: picking a single colony of *Russula natans* RA and inoculating it into a fermentation medium, culturing it at 20-30 ℃ and 150-200 rpm for 1-2 days, transferring it into the fermentation medium at a rate of 5%-20% (100-200 mL / 500 mL), culturing it at 20-30 ℃ and 150-200 rpm for 1-2 days to obtain the fermentation broth, and centrifuging the fermentation broth to obtain mycelial sludge; The fermentation medium comprises the following components by mass of distilled water: 0.3%~0.6% peptone, 0.2%~0.7% yeast extract, 0.04%~0.06% magnesium sulfate, 0.5%~2% brown sugar, and 0.5%~1.5% sodium chloride; the pH of the fermentation medium is 7.0~7.

2.

4. The method for preparing the *Russula pulcherrima* inoculant according to claim 3, characterized in that, The mass ratio of mycelium raffinis RA to peat powder is 1:

5. The sieve mesh size is 20 mesh; The preparation method of mycelial sludge of *Russula natans* RA includes: picking a single colony of *Russula natans* RA and inoculating it into a fermentation medium, culturing it at 28 ℃ and 200 rpm for 1 day, transferring it to the fermentation medium at a rate of 10% (100 mL / 500 mL), culturing it at 28 ℃ and 200 rpm for 1 day to obtain the fermentation broth, and centrifuging the fermentation broth to obtain mycelial sludge; Centrifugation conditions: 6000 rpm for 10 min; The fermentation medium comprises the following components by mass of distilled water: 0.5% peptone, 0.5% yeast extract, 0.05% magnesium sulfate, 1% brown sugar, and 1% sodium chloride; the pH of the fermentation medium is 7.0-7.

2.

5. The application of the *Russula macrantha* inoculant according to claim 1 or the *Russula macrantha* inoculant obtained by the preparation method according to any one of claims 2 to 4 in the decomposition of inorganic phosphorus in soil, production of indoleacetic acid, production of ferrophosphate, inhibition of crop diseases, or promotion of crop growth, wherein, The crop disease is corn root rot, sorghum leaf spot or wheat root rot, and the *Rhus chinensis* inoculant is used to inhibit at least one of the following pathogens: *Fusarium oxysporum*, *Plasmodium sorghum*, *Fusarium solani*, *Alternaria sorghum*, *Rhizoctonia solani* and *Cyclocarya spp.* 6. A microbial granular fertilizer, characterized in that, The product comprises, by weight, the following raw material components: 50-70 parts organic fertilizer, 10-15 parts diatomaceous earth, 5-15 parts biochemical potassium humate, 5-10 parts calcium magnesium phosphate fertilizer, 2-3 parts chitosan oligosaccharide, 1-3 parts seaweed extract, 1-2 parts fish protein, 0.1-0.3 parts *Streptomyces cocoa* inoculant, and 5-7 parts *Russula natans* inoculant, wherein the *Streptomyces cocoa* inoculant contains *Streptomyces cocoa* with preservation number CGMCC No. 13080. Streptomyces cacaoi FN, the *Russula natans* inoculum contains *Russula natans* with preservation number CGMCC No. 35889. Rouxiella aceris )RA.

7. The microbial granular fertilizer according to claim 6, characterized in that, By weight, it includes the following raw material components: 65 parts organic fertilizer, 10 parts diatomaceous earth, 10 parts biochemical potassium humate, 5 parts calcium magnesium phosphate fertilizer, 3 parts chitosan oligosaccharide, 1 part seaweed extract, 1 part fish protein, 0.1 parts cocoa streptomyces inoculant and 5 parts maple rumeniaceae inoculant. The activity level of Streptomyces cocoa FN in the microbial granular fertilizer is not less than 3.0 × 10⁻⁶. 8 CFU / g, the bacterial activity of *Russula natans* RA is not less than 2.0 × 10⁻⁶ CFU / g. 8 CFU / g; The preparation method of the Streptomyces cocoa inoculant includes: Preparation of spore suspension: Sterile water was added to the slant of 2216E solid culture medium containing Streptomyces cocoa FN, and then the spores were scraped off. The mixture was shaken to obtain a spore suspension with a cell concentration of 10. 8 ~10 9 CFU / mL; Seed culture: The spore suspension was inoculated into the seed culture medium at an inoculation rate of 1% to 3%, and cultured in a shake flask at 28 ℃ and 160 to 240 rpm for 90 to 100 h to obtain the seed culture. Solid-state fermentation culture: The seed liquid was inoculated into a solid-state fermentation medium with a water content of 50% at an inoculation rate of 5%~15% mL / g, fermented in a tray at 28 ℃ for 3~6 days, air-dried at 20~30 ℃, ground with a pulverizer, and sieved to obtain the Streptomyces cocoa inoculum.

8. The microbial granular fertilizer according to claim 7, characterized in that, In the seed culture step, the spore suspension is inoculated into the seed culture medium at an inoculation rate of 1%, and cultured in a shake flask at 28°C and 200 rpm for 96 h to obtain the seed culture. In the solid fermentation culture step, the seed liquid is inoculated into a solid fermentation medium with a water content of 50% at an inoculation rate of 10% mL / g, and fermented in a tray at 28 ℃ for 4 days. From the beginning to the end of the fermentation, the water content of the solid fermentation medium is maintained at a constant 50%. During the fermentation, the medium is turned over 2-3 times. After the fermentation is completed, the medium is air-dried at 28 ℃, ground with a pulverizer, and the pulverized material that passes through a 20-mesh sieve is collected to obtain the Streptomyces cocoa inoculum. The viability of the *Streptomyces cocoa* inoculant is not less than 2 × 10⁻⁶. 11 CFU / g; The 2216E solid culture medium, per L volume, comprises the following components: 5 g of bacterial peptone No. 2, 1 g of yeast extract, 20 g of agar, with the remainder being distilled water, and the pH being natural. The seed culture medium, per L volume, comprises the following components: 10 g corn flour, 10 g peptone, 5 g yeast extract, 2 g dipotassium hydrogen phosphate, 0.3 g magnesium sulfate, with the remainder being distilled water and a natural pH. The solid fermentation medium comprises the following components by mass fraction: 20% rice husk, 44.7% wheat bran, 22% corn flour, 12% soybean meal, 0.8% calcium carbonate, 0.3% dipotassium hydrogen phosphate, 0.2% magnesium sulfate, and natural pH.

9. The method for preparing microbial granular fertilizer according to any one of claims 6 to 8, characterized in that, Includes the following steps: The raw material components are mixed in proportion, crushed, and sieved to obtain a crushed material with a particle size of less than 1 mm; the moisture content of the crushed material is adjusted to 12%~18%, and granulation and shaping are carried out in sequence to obtain particles with a particle size of 2.5~3.5 mm. The particles are dried to a moisture content of 9%~12%, sieved, and microbial granular fertilizer with a particle size of 3~4 mm is obtained.

10. The application of the microbial granular fertilizer according to any one of claims 6 to 8 or the microbial granular fertilizer obtained by the preparation method according to claim 9 in the planting of field crops.

Images