Preparation method and application of microbial bacterial fertilizer for corn planting

Abstract

This invention relates to the field of agricultural microbial fertilizer technology, specifically to a method for preparing and applying a microbial fertilizer for corn cultivation. The microbial fertilizer uses *Bacillus amyloliquefaciens* (BAM). Bacillus amyloliquefaciens B2 is the core functional microorganism, and its fermentation broth is inoculated into a fermentation system containing animal manure, straw powder, modified biochar, and urea for composting fermentation. The modified biochar is obtained by modifying corn straw biochar with magnesium chloride hexahydrate, attapulgite, dicyandiamide, Gly-Pro, and a combination of ferulic acid and tannic acid. This microbial fertilizer can improve the activity of microorganisms and nutrient conversion efficiency during corn cultivation, promoting plant growth. It can also improve the activity of microorganisms and nutrient conversion efficiency in the soil, improve the rhizosphere microecological environment, promote the absorption and utilization of nutrients by corn, thereby promoting plant growth, increasing biomass accumulation, reducing the amount of chemical fertilizer used, and improving the soil ecological environment.

Description

Technical Field

[0001] This invention relates to the field of agricultural microbial fertilizer technology, and in particular to a method for preparing and applying microbial fertilizer for corn cultivation. Background Technology

[0002] As a globally important food and feed crop, the high and stable yield of corn largely depends on fertilizer input. Chinese invention patent (CN113755394B) discloses a microbial fertilizer using Bacillus amyloliquefaciens loaded on a biochar carrier. The technical route can be summarized as follows: using biochar as a carrier, Bacillus amyloliquefaciens fermentation broth is mixed with biochar in a certain proportion, allowing the bacteria to be adsorbed / loaded onto the surface of the biochar, thus producing a biochar-based microbial fertilizer. This fertilizer can be used to promote crop growth, with a focus on its application in cucumbers in the disclosure. The essential characteristics of this scheme are: the carrier is single-component biochar; the functional bacteria is Bacillus amyloliquefaciens SQR9; the preparation method is relatively simple, mainly involving mixed loading; and the goal is to solve the problems of short survival time, transportation, and shelf life of the microbial fertilizer.

[0003] However, the aforementioned existing technologies still have certain shortcomings: their functional bacterial systems are relatively simple, and the colonization ability and sustained activity of the strains in complex soil environments are limited; at the same time, the carrier structure has not undergone multi-level functional modification, making it difficult to achieve effective regulation and slow-release synergy of nutrients; and the lack of systematic construction with organic compost substrates makes its effects on soil nutrient supply, microecological regulation and continuous crop growth promotion unstable during long-term action, showing certain limitations in crop systems with high fertilizer requirements such as corn. Summary of the Invention

[0004] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is: how to provide a microbial fertilizer suitable for corn planting and its preparation method, so that the prepared microbial fertilizer can preferentially utilize specific functional strains of Bacillus amyloliquefaciens (B. amyloliquefaciens). Bacillus amyloliquefaciens B2 achieves efficient amplification and stable survival of microorganisms during fermentation and composting, and works synergistically with modified biochar and organic compost substrate to significantly enhance the colonization and sustained activity of microorganisms in the soil environment, strengthen nutrient conversion and slow-release supply capacity, and ultimately achieve a stable growth-promoting effect on corn.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] This invention provides Bacillus amyloliquefaciens (BAM) Bacillus amyloliquefaciens The application of B2 in the preparation of microbial fertilizer for corn planting, the preservation number of Bacillus amyloliquefaciens B2 is CGMCC NO.35462.

[0007] This invention provides a microbial fertilizer for corn cultivation, comprising animal manure, straw powder, modified biochar, urea, and Bacillus amyloliquefaciens (B. amyloliquefaciens). Bacillus amyloliquefaciens Fermentation broth of B2; the preservation number of Bacillus amyloliquefaciens B2 is CGMCC NO.35462.

[0008] Furthermore, the inoculation amount of Bacillus amyloliquefaciens B2 fermentation broth is 1.0%-2.0% of the total mass of the microbial fertilizer.

[0009] Furthermore, by weight, the composition is: 300-500 parts animal manure, 100-200 parts straw powder, 100-150 parts modified biochar, and 30-50 parts urea.

[0010] Furthermore, the modified biochar is prepared through the following steps:

[0011] (1) Dissolve magnesium chloride hexahydrate in deionized water, add attapulgite clay, and stir to form a suspension; add corn straw biochar to the suspension, stir, let stand, and then separate. The resulting solid is dried and heat-treated to obtain the first material.

[0012] (2) Dissolve dicyandiamide in deionized water, add it to the first material, mix, stir and dry to obtain the second material;

[0013] (3) Dissolve Gly-Pro in deionized water, add it to the second material and shake to adsorb, then freeze dry to obtain the third material;

[0014] (4) Add ferulic acid and tannic acid to a 30% ethanol-water solution and stir to obtain the fourth material;

[0015] (5) The fourth material is sprayed onto the surface of the third material, left to stand, dried and cured to obtain the modified biochar.

[0016] Furthermore, in the process of preparing modified biochar, the total amount of ferulic acid and tannic acid added is 2%-4% of the mass of corn straw biochar, and the mass ratio of ferulic acid to tannic acid is (3-5):(2-3).

[0017] Furthermore, in step (5), the spraying speed is 10 mL / min, and the drying and curing conditions are drying at 50 ℃ for 8-10 h, and then heating to 80 ℃ for curing for 2 h.

[0018] The present invention provides the application of the above-mentioned microbial fertilizer for corn planting in any one of (1) to (4);

[0019] (1) Increase corn plant height;

[0020] (2) Increase the SPAD value;

[0021] (3) Increase the dry weight of corn;

[0022] (4) Increase the nitrogen content in the leaves.

[0023] This invention provides a method for preparing microbial fertilizer for corn cultivation: by weight, it includes 300-500 parts animal manure, 100-200 parts straw powder, 100-150 parts modified biochar, 30-50 parts urea, and Bacillus amyloliquefaciens (…). Bacillus amyloliquefaciens The fermentation broth of B2; the above components are mixed to obtain a mixture, and the mixture is composted to obtain the microbial fertilizer; wherein, the modified biochar is obtained through the following steps:

[0024] (1) Dissolve magnesium chloride hexahydrate in deionized water, add attapulgite clay, and stir to form a suspension; add corn straw biochar to the suspension, stir, let stand, and then separate. The resulting solid is dried and heat-treated to obtain the first material.

[0025] (2) Dissolve dicyandiamide in deionized water, add it to the first material, mix, stir and dry to obtain the second material;

[0026] (3) Dissolve Gly-Pro in deionized water, add it to the second material and shake to adsorb, then freeze dry to obtain the third material;

[0027] (4) Add ferulic acid and tannic acid to a 30% (v / v) ethanol-water solution and stir to obtain the fourth material;

[0028] (5) The fourth material is sprayed onto the surface of the third material, left to stand, dried and cured to obtain the modified biochar.

[0029] Finally, a microbial fertilizer for corn cultivation was produced.

[0030] Through the above technical solution, the present invention utilizes Bacillus amyloliquefaciens (BAM) Bacillus amyloliquefaciens B2 serves as the core functional strain. Through multi-level functionalized modified biochar, animal manure, straw powder, and urea, a compost-type microbial fertilizer system is constructed. This enables the functional bacteria to achieve efficient expansion and stable loading during fermentation, while maintaining high colonization capacity and continuous activity in the soil environment. At the same time, it enhances nutrient adsorption and slow-release regulation capabilities, forming a synergistic system of "functional bacteria - modified carrier - organic matrix". This effectively improves the soil micro-ecological environment, promotes corn root growth and nutrient absorption, and enhances the persistence and yield-promoting effects of the microbial fertilizer. Attached Figure Description

[0031] Figure 1 This invention relates to the state of Bacillus amyloliquefaciens B2 in LB medium;

[0032] Figure 2 The phylogenetic tree constructed for Bacillus amyloliquefaciens B2 in this invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only 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.

[0034] Unless otherwise specified, all techniques or conditions used in the embodiments are conventional methods or performed according to techniques or conditions described in the literature in this field, or according to product instructions. Experimental materials used in this invention, unless otherwise specified, are all conventional products that can be purchased from legitimate channels or prepared according to conventional methods in this field. Instruments used in this invention, unless otherwise specified, are all conventional instruments that can be purchased from legitimate channels.

[0035] The LB liquid culture medium formula includes: 10 g tryptone, 5 g yeast extract, and 10 g sodium chloride per 1000 mL of water, with the pH adjusted to 7.2-7.4, and sterilized at 121℃ for 20 min.

[0036] The LB solid medium formula includes: 10 g tryptone, 5 g yeast extract, 10 g sodium chloride, and 15 g agar per 1000 mL of water, with the pH adjusted to 7.2-7.4, and sterilized at 121℃ for 20 min.

[0037] Pinellia ternata, Shenqu (a type of fermented medicinal herb), and alum were all purchased from the Bozhou Traditional Chinese Medicine Market in Anhui Province; ginger was purchased from the Harbin Vegetable Market; and flour was purchased from Jinshahe Group.

[0038] Reference Appendix Figure 1 and 2 This invention provides a method for preparing microbial fertilizer for corn cultivation.

[0039] Example 1

[0040] Bacillus amyloliquefaciens ( Bacillus amyloliquefaciens B2 is obtained by separating and purifying fermented Pinellia ternata, specifically including the following steps:

[0041] 1. Isolation and identification of strains

[0042] (1) Preparation of fresh samples of naturally fermented Pinellia ternata, the specific preparation process is as follows:

[0043] The preparation of ginger juice includes the following steps: cut fresh ginger into pieces, add an appropriate amount of water and juice it, and convert 1 g of ginger into 1 mL of ginger juice to make 1 g / mL ginger juice;

[0044] Take 160 g of Pinellia ternata and 10 g of alum, grind them into fine powder, mix them with 32 g of flour and 5 g of Shenqu (medicated leaven), add 20 mL of ginger juice to water to make 60-80 mL, mix the above components well, and knead into a ball (it can be formed into a ball when squeezed, but will crumble when touched).

[0045] (2) The prepared Pinellia ternata in step (1) is naturally fermented at 30°C and 85% humidity.

[0046] (3) Take 1 mg of fresh sample at different fermentation time points of 0 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h respectively, and add it to a 150 mL Erlenmeyer flask containing 9 mL of sterile water and 2 mm glass shaking beads in a sterile environment. Shake at 140 r / min for about 20 min to allow the bacteria to spread fully. Use a 1 mL sterile pipette to draw 1 mL of bacterial suspension from the Erlenmeyer flask and add it to a sterile tube containing 9 mL of sterile water to obtain 10 -1 The bacterial suspension was prepared into 10 batches according to the method. -2 10 -4 10 -6 10 -8 Bacterial suspensions of equal dilution.

[0047] (4) Use a sterile pipette to draw 100 μL of 10 -2 10 -4 10 -6 10 -8 The bacterial suspension was placed in calcium oxalate solid medium (each dilution was repeated 3 times). The suspension was then gently and evenly spread on the surface of the calcium oxalate solid medium using a sterile metal spreader. The calcium oxalate solid medium was placed in a 30℃ biochemical incubator and incubated for 2-5 days. The growth of the bacterial strain was observed until colonies appeared.

[0048] (5) Take the colonies obtained in step (4), and when they are growing well, pick the tips of the hyphae and inoculate them onto new LB solid medium. Incubate them upside down in a 30℃ biochemical incubator for 1-2 days for isolation and purification until a single colony is obtained. Figure 1 As shown, the obtained colonies are round with slightly wavy edges, milky white, opaque, and have a smooth surface with slight wrinkles. This strain was named B2.

[0049] Strain B2 was sent to Shanghai Ling'en Biotechnology Co., Ltd., which performed 16S rRNA gene sequencing using primers 27F / 1492R.

[0050] Primer 27F: AGRGTTYGATYMTGGCTCAG (SEQ ID NO.1);

[0051] Primer 1492R: RGYTACCTTGTTACGACTT (SEQ ID NO.2);

[0052] All the primers mentioned above were provided by Shanghai Lingen Biotechnology Co., Ltd.

[0053] The sequence of the 16S rRNA gene of strain B2 is shown below:

[0054]

[0055] The sequencing results were compared using BLAST on the NCBI website, and a phylogenetic tree was constructed, such as... Figure 2 As shown, based on morphological observation and phylogenetic tree construction results, strain B2 was identified as Bacillus amyloliquefaciens (Bacillus). Bacillus amyloliquefaciens ), named Bacillus amyloliquefaciens ( Bacillus amyloliquefaciens B2, deposited at the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, China, on July 30, 2025, with accession number CGMCC No. 35462.

[0056] 2. Preparation of fermentation broth for bacterial strains

[0057] The above-mentioned Bacillus amyloliquefaciens B2 was inoculated from LB solid medium into LB liquid medium and cultured with shaking at 30°C and 140 r / min for 12-18 h to obtain seed culture. The seed culture was then inoculated into LB liquid medium at an inoculation rate of 1-2% (v / w) and cultured with shaking at 30°C and 160 r / min. The absorbance (OD) of the bacterial culture at 600 nm was measured using a spectrophotometer. 600 When OD 600 When the value reaches 1.5-2.0, the concentration of the fermentation broth is greater than 1×10⁻⁶. 9 The fermentation broth of Bacillus amyloliquefaciens B2 was obtained by measuring cfu / g.

[0058] Example 2

[0059] 1. Preparation method of modified biochar

[0060] S101. Weigh 8 g of magnesium chloride hexahydrate and dissolve it in 500 mL of deionized water. Stir the solution at 300 rpm for 10 min using a magnetic stirrer until fully dissolved. Then add 15 g of attapulgite and continue stirring at 400 rpm for 30 min to form a suspension. Add 100 g of corn straw biochar (passed through a 100-mesh sieve) to the suspension. Heat the solution to 60 °C and stir at 500 rpm for 2 h to allow Mg²⁺ and attapulgite to fully load into the pores. After the reaction is complete, allow the solution to stand for 12 h for aging. Then filter the solution and dry the resulting solid at 80 °C for 12 h. Transfer the solid to a muffle furnace and heat it at 300 °C for 2 h at 5 °C / min. After cooling to room temperature, the first material is obtained.

[0061] S102. Weigh 2 g of dicyandiamide and dissolve it in 100 mL of deionized water. Add the first material to the solution and stir at 300 rpm for 1 h in a 40 ℃ water bath to allow the dicyandiamide to be fully adsorbed and loaded onto the surface and pores of the material. Then dry it at 60 ℃ to constant weight to obtain the second material.

[0062] S103. Weigh 0.8 g of Gly-Pro and dissolve it in 80 mL of deionized water. Add the solution to the second material and adsorb it by shaking at 150 rpm for 2 h at room temperature. Then freeze-dry it at -50℃ for 48 h to obtain the third material.

[0063] S104. Prepare 120 mL of 30% (v / v) ethanol-water solution, add 1.2 g ferulic acid in a 40℃ water bath, stir at 400 rpm for 20 min, then add 0.8 g tannic acid and continue stirring for 20 min to obtain the fourth material;

[0064] S105. The fourth material is uniformly sprayed onto the surface of the third material at a rate of 10 mL / min, and continuously turned during the spraying process to ensure uniform distribution. After spraying, the material is placed in a sealed container and left to stand at 40 °C for 12 h, turning it every 2-3 h. Then, it is dried at 50 °C for 8-10 h to slowly remove the solvent, and then heated to 80 °C to cure for 2 h. After cooling to room temperature, the modified biochar is obtained.

[0065] 2. Preparation method of microbial fertilizer

[0066] Weigh 300 g of well-rotted animal manure and 100 g of straw powder. The animal manure can be one or more of chicken manure, cow manure, sheep manure, pig manure, and horse manure. Mix them evenly as the base material. Adjust the moisture content of the system to 35% by spraying an appropriate amount of deionized water. Then add 100 g of modified biochar and mix for 10 min using a mixer. Add 30 g of urea and continue mixing. Adjust the pH to 6.5. Then inoculate the fermentation broth of Bacillus amyloliquefaciens B2 prepared in Example 1 at 1.0% of the total mass of the material. Stir evenly to obtain a mixture. Place the mixture in the fermentation site and use the windrow composting method. Control the fermentation temperature within 30℃ and carry out aerobic fermentation for 10 days. Turn the pile every 2 days during the fermentation process to adjust the moisture content to 35% to obtain microbial fertilizer.

[0067] Example 3

[0068] 1. Preparation method of modified biochar

[0069] S101. Weigh 10 g of magnesium chloride hexahydrate and dissolve it in 500 mL of deionized water. Stir at 300 rpm for 10 min using a magnetic stirrer until fully dissolved. Then add 20 g of attapulgite clay and continue stirring at 400 rpm for 30 min to form a suspension. Add 100 g of corn straw biochar (passed through a 100-mesh sieve) to the suspension, heat to 60 ℃, and stir at a constant temperature of 500 rpm for 2 h to allow the magnesium to dissolve. 2+ The attapulgite clay was fully loaded into the pores. After the reaction was completed, it was allowed to stand for aging for 12 hours. Then, it was separated by filtration. The resulting solid was dried at 80°C for 12 hours and then transferred to a muffle furnace and heated to 300°C at 5°C / min for 2 hours. After cooling to room temperature, the first material was obtained.

[0070] S102. Weigh 3 g of dicyandiamide and dissolve it in 100 mL of deionized water. Add the first material to the solution and stir at 300 rpm for 1 h in a 40 ℃ water bath to allow the dicyandiamide to be fully adsorbed and loaded onto the surface and pores of the material. Then dry it at 60 ℃ to constant weight to obtain the second material.

[0071] S103. Weigh 1 g of Gly-Pro and dissolve it in 80 mL of deionized water. Add the solution to the second material and adsorb it by shaking at 150 rpm for 2 h at room temperature. Then freeze-dry it at -50℃ for 48 h to obtain the third material.

[0072] S104. Prepare 120 mL of 30% (v / v) ethanol-water solution, add 1.5 g ferulic acid in a 40℃ water bath, stir at 400 rpm for 20 min, then add 0.9 g tannic acid and continue stirring for 20 min to obtain the fourth material.

[0073] S105. The fourth material is uniformly sprayed onto the surface of the third material at a rate of 10 mL / min, and continuously turned during the spraying process to ensure uniform distribution. After spraying, the material is placed in a sealed container and left to stand at 40 ℃ for 12 h, turning it over every 2-3 h. Then, it is placed in a drying oven and dried at 50 ℃ for 8-10 h to slowly remove the solvent. The temperature is then raised to 80 ℃ for 2 h to cure. After cooling to room temperature, the modified biochar is obtained.

[0074] 2. Preparation method of microbial fertilizer

[0075] Weigh 400 g of well-rotted animal manure and 150 g of straw powder, mix them evenly as the base raw material, and adjust the moisture content of the system to 35% by spraying an appropriate amount of deionized water. Then add 120 g of modified biochar and mix for 10 min using a mixer. Then add 40 g of urea and continue mixing. Adjust the pH to 7.0. Then inoculate the fermentation broth of Bacillus amyloliquefaciens B2 prepared in Example 1 at 1.5% of the total mass of the material, and stir evenly to obtain a mixture. Place the mixture in the fermentation site and use the windrow composting method to control the fermentation temperature within the range of 35℃ for aerobic fermentation for 12 days. Turn the pile every 2 days during the fermentation process and adjust the moisture content to 35% to obtain microbial fertilizer.

[0076] Example 4

[0077] 1. Preparation method of modified biochar

[0078] S101. Weigh 15 g of magnesium chloride hexahydrate according to the mass ratio and dissolve it in 500 mL of deionized water. Stir at 300 rpm for 10 min with a magnetic stirrer to ensure complete dissolution. Then add 30 g of attapulgite and continue stirring at 400 rpm for 30 min to form a suspension. Add 120 g of corn straw biochar (passed through a 100-mesh sieve) to the suspension, heat to 60 ℃ and stir at 500 rpm for 2 h to allow Mg²⁺ and attapulgite to fully load into the pores. After the reaction is complete, let it stand for 12 h for aging. Then filter and separate the solid. Dry the obtained solid at 80 ℃ for 12 h and then heat it in a muffle furnace at 300 ℃ for 2 h with a temperature increase of 5 ℃ / min. After cooling to room temperature, the first material is obtained.

[0079] S102. Weigh 5 g of dicyandiamide and dissolve it in 100 mL of deionized water. Add the first material to the solution and stir at 300 rpm for 1 h in a 40 ℃ water bath to allow the dicyandiamide to be fully adsorbed and loaded onto the surface and pores of the material. Then dry it at 60 ℃ to constant weight to obtain the second material.

[0080] S103. Weigh 2 g of Gly-Pro and dissolve it in 80 mL of deionized water. Add the solution to the second material and adsorb it by shaking at 150 rpm for 2 h at room temperature. Then freeze-dry it at -50℃ for 48 h to obtain the third material.

[0081] S104. Prepare 200 mL of 30% (v / v) ethanol-water solution, add 3.0 g ferulic acid in a 40℃ water bath, stir at 400 rpm for 20 min, then add 1.8 g tannic acid, and continue stirring for 20 min to obtain the fourth material;

[0082] S105. The fourth material is uniformly sprayed onto the surface of the third material at a rate of 10 mL / min, and continuously turned during the spraying process to ensure uniform distribution. After spraying, the material is placed in a sealed container and left to stand at 40 °C for 12 h, turning it every 2-3 h. Then, it is dried at 50 °C for 8-10 h to slowly remove the solvent, and then heated to 80 °C to cure for 2 h. After cooling to room temperature, the modified biochar is obtained.

[0083] 2. Preparation method of microbial fertilizer

[0084] Weigh 500 g of well-rotted animal manure and 200 g of straw powder, mix them evenly as the base raw material, and adjust the moisture content of the system to 35% by spraying an appropriate amount of deionized water. Then add 150 g of modified biochar and mix for 10 min using a mixer. Then add 50 g of urea and continue mixing. Adjust the pH to 7.5. Then inoculate the fermentation broth of Bacillus amyloliquefaciens B2 prepared in Example 1 at 2.0% of the total mass of the material, and stir evenly to obtain a mixture. Place the mixture in the fermentation site and use the windrow composting method to control the fermentation temperature within the range of 45℃ for aerobic fermentation for 15 days. Turn the pile every 2 days during the fermentation process and adjust the moisture content to 40% to obtain microbial fertilizer.

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 2 is that step S103 is omitted, while all other conditions remain unchanged.

[0087] Comparative Example 2

[0088] The difference between Comparative Example 1 and Example 2 is that steps S104-S105 are not included, the modified biochar is prepared by step S103, and all other conditions remain unchanged.

[0089] Comparative Example 3

[0090] The microbial fertilizer used was prepared according to the microbial fertilizer preparation method disclosed in patent CN110982730B.

[0091] Experimental Example

[0092] Tested variety: Longkeyu 103;

[0093] This experiment was conducted in a maize field in Harbin, Heilongjiang Province. The soil type was typical black soil, with a consistent previous crop and uniform soil fertility. The experiment included experimental groups, a control group, and a blank control group. The experimental groups used the microbial fertilizers prepared in Examples 2-4 and Comparative Examples 1-3. The control group received commercially available organic fertilizer, whose main components were Bacillus subtilis and commercially available compound fertilizer (N-P2O5-K2O=19-19-19). The blank control group received no fertilizer. Each treatment had three replicates, using a randomized block design. Each plot was 6 m², with a row spacing of 0.6 m, and 36-50 plants per plot. Buffer zones were placed between plots to reduce mutual interference. Fertilizer was applied at a rate of 180 kg N / hm² (pure nitrogen). Plant height was measured on days 15 and 30 after sowing. Ten plants were randomly selected from each plot for measurement, and the average value was taken. Plant height was measured on day 45 after sowing. Sampling was carried out, with 10 corn plants randomly selected from each plot. The SPAD (relative chlorophyll content) value of the leaves was measured using a SPAD-502 chlorophyll meter. The aboveground parts were cut, and after removing surface attachments, they were blanched at 105℃ for 30 min, and then dried at 65℃ to constant weight. The dry weight of the aboveground parts was measured. Fresh leaves were collected, washed, and dried. They were blanched at 105℃ for 30 min, and then dried at 65℃ for 24 h. The dried samples were crushed and sieved. The nitrogen content of the leaves was determined by the Kjeldahl method. The results are shown in Table 1.

[0094] Table 1 Effects of different treatments on maize growth indicators

[0095] Processing group Plant height 15d (cm) Plant height 30d (cm) SPAD Dry weight (g) Leaf nitrogen content (g / kg) Example 2 23.81±1.35 72.66±4.35 34.2±1.1 27.31±1.61 2.98±0.17 Example 3 26.94±1.64 75.82±4.47 35.7±1.3 29.66±1.74 3.04±0.18 Example 4 27.53±1.68 77.24±4.63 37.4±1.0 31.24±1.84 3.32±0.20 Comparative Example 1 20.12±1.21 60.81±3.58 28.4±1.7 21.76±1.30 2.14±0.12 Comparative Example 2 21.51±1.31 63.52±3.81 29.0±1.2 22.83±1.36 2.49±0.14 Comparative Example 3 20.90±1.25 58.63±3.40 27.8±1.7 20.94±1.25 2.11±0.12 Commercially available organic fertilizer 22.65±1.36 61.47±3.65 28.3±1.7 24.52±1.47 2.55±0.15 Commercially available compound fertilizer 20.33±1.21 55.64±3.36 25.8±1.6 20.75±1.17 2.16±0.12 Blank control 18.56±1.21 42.36±2.49 20.6±1.2 12.89±0.77 1.52±0.08

[0096] The results are shown in Table 1. The maize plants treated in Examples 2-4 all showed better growth than those treated in Comparative Examples 1-3 and the commercial fertilizer treatment. Specifically, the maize treated in Examples 3 and 4 exhibited higher plant height as early as 15 days after sowing, indicating a significant promoting effect on early crop growth. This advantage further expanded at 30 and 45 days, with dry weight and leaf nitrogen content reaching their highest levels, demonstrating a significant effect on sustained nutrient supply and nitrogen absorption. Compared to Comparative Example 3, the maize treated in Example 4 showed a 34.5% increase in SPAD value, a 49.2% increase in dry weight, and a 57.3% increase in leaf nitrogen content. Compared to commercially available organic fertilizer, the SPAD value increased by 32.2%, dry weight by 27.4%, and leaf nitrogen content by 30.2%. These results indicate that Example 4, through optimization of the component ratios, achieved a synergistic effect among the components, significantly improving maize growth, photosynthetic efficiency, and nitrogen absorption and utilization efficiency.

[0097] 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 strain of Bacillus amyloliquefaciens ( Bacillus amyloliquefaciens The application of B2 in the preparation of microbial fertilizer for corn cultivation is characterized by, The preservation number of Bacillus amyloliquefaciens B2 is CGMCC NO.35462.

2. A microbial fertilizer for corn cultivation, characterized in that, Including animal manure, straw powder, modified biochar, urea, and Bacillus amyloliquefaciens (BAM). Bacillus amyloliquefaciens Fermentation broth of B2; the preservation number of Bacillus amyloliquefaciens B2 is CGMCC NO.35462.

3. The microbial fertilizer for corn cultivation according to claim 2, characterized in that, The inoculation amount of Bacillus amyloliquefaciens B2 fermentation broth is 1.0%-2.0% of the total mass of microbial fertilizer.

4. The microbial fertilizer for corn cultivation according to claim 2, characterized in that, By weight, the composition is: 300-500 parts animal manure, 100-200 parts straw powder, 100-150 parts modified biochar, and 30-50 parts urea.

5. The microbial fertilizer for corn cultivation according to claim 2, characterized in that, Modified biochar is prepared through the following steps: (1) Dissolve magnesium chloride hexahydrate in deionized water, add attapulgite clay, and stir to form a suspension; add corn straw biochar to the suspension, stir, let stand, and then separate. The resulting solid is dried and heat-treated to obtain the first material. (2) Dissolve dicyandiamide in deionized water, add it to the first material, mix, stir and dry to obtain the second material; (3) Dissolve Gly-Pro in deionized water, add it to the second material and shake to adsorb, then freeze dry to obtain the third material; (4) Add ferulic acid and tannic acid to a 30% (v / v) ethanol-water solution and stir to obtain the fourth material; (5) The fourth material is sprayed onto the surface of the third material, left to stand, dried and cured to obtain the modified biochar.

6. The microbial fertilizer for corn cultivation according to claim 5, characterized in that, In the preparation of modified biochar, the total amount of ferulic acid and tannic acid added is 2%-4% of the mass of corn straw biochar, and the mass ratio of ferulic acid to tannic acid is (3-5):(2-3).

7. The microbial fertilizer for corn cultivation according to claim 5, characterized in that, The spraying speed in step (5) is 10 mL / min, and the drying and curing conditions are drying at 50 ℃ for 8-10 h, and then heating to 80 ℃ for 2 h.

8. The use of the microbial fertilizer for corn cultivation as described in claim 7 in any one of (1) to (4); (1) Increase corn plant height; (2) Increase the SPAD value; (3) Increase the dry weight of corn; (4) Increase the nitrogen content in the leaves.

9. A method for preparing the microbial fertilizer for corn planting as described in claim 7, characterized in that, The process includes the following steps: mixing animal manure, straw powder, modified biochar, urea, and fermentation broth of Bacillus amyloliquefaciens B2 to obtain a mixture, and then composting the mixture to produce the microbial fertilizer.

10. The preparation method according to claim 9, characterized in that, The composting fermentation temperature is 30-45℃, the fermentation time is 10-15 days, and the moisture content is 35%-40%.

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