Improved composite microbial fertilizer for soil acidification and preparation method thereof
By utilizing the microbial agents and nano-selenium complexes in the compound microbial fertilizer, the adverse effects of soil acidification on rice growth in existing technologies have been resolved, achieving soil acidification improvement and rice yield enhancement, and establishing a rapid-long-lasting-dynamic acidification adjustment mechanism.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU AGRI ANIMAL HUSBANDRY VOCATIONAL COLLEGE
- Filing Date
- 2025-11-20
- Publication Date
- 2026-06-26
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of soil improvement technology, specifically to a compound microbial fertilizer for improving soil acidification and its preparation method. Background Technology
[0002] Soil acidification is one of the main factors affecting agricultural development. Excessively low soil pH negatively impacts plant growth. Aluminum constitutes approximately 7.1% of the Earth's crust by mass, making it the third most abundant element in soil after oxygen and silicon, and the most abundant metallic element. Aluminum in soil often exists in various chemical forms, the proportion of which depends primarily on soil pH. When soil pH < 5, aluminum precipitates in ionic form. When the concentration of active aluminum ions in the soil exceeds the tolerance limit of plant roots, it affects the root system, mainly manifesting as short, deformed, curled, and easily broken roots. Plant growth is significantly hindered, leading to poor plant growth and development, and even plant death.
[0003] Currently, methods for improving soil acidification mainly include applying chemical amendments such as lime and planting green manure. While chemical amendments can quickly adjust soil pH, long-term use can damage soil structure and affect the balance of soil microbial communities. Agronomic measures, although relatively environmentally friendly, have slow improvement effects and are difficult to meet actual production needs. Microbial fertilizers, due to their advantages in improving the soil microbial environment and promoting soil nutrient transformation, have gradually become a research hotspot in soil improvement. However, existing microbial fertilizers suffer from problems such as insignificant effects and limited functionality in improving soil acidification, failing to effectively address the adverse effects of acidic soil on rice growth. Therefore, developing a highly efficient, environmentally friendly compound microbial fertilizer that can significantly improve soil acidification and increase rice yield is urgently needed. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a compound microbial fertilizer for improving soil acidification and its preparation method.
[0005] The objective of this invention can be achieved through the following technical solutions: A compound microbial fertilizer for improving soil acidification comprises the following components by weight: 10-20 parts microbial agent, 0.3-0.5 parts modified nano-selenium complex, 8-10 parts quicklime, 20-40 parts biochar, 8-10 parts humic acid, 20-30 parts decomposed organic matter, and 2-3 parts trehalose.
[0006] Furthermore, the preparation method of the microbial inoculant is as follows: S1. *Bacillus belye* was cultured on LB medium at 28-37℃ and 150-200 rpm for 14-24 hours to obtain *Bacillus belye* culture; *Lactobacillus plantarum* was cultured on MRS medium at 30-37℃ for 18-36 hours to obtain *Lactobacillus plantarum* culture; *Streptomyces griseus* was cultured on Gao's No. 1 medium at 25-30℃ and 160-200 rpm for 5-7 days to obtain *Streptomyces griseus* culture. S2. Mix the three bacterial cultures and inoculate them into a composite culture medium. Culture the mixture at 25-35℃ and 120-180 rpm for 2-3 days until the spore formation rate reaches 80-90%. S3. Centrifuge to collect bacterial cells, resuspend in buffer solution, spray dry to obtain microbial inoculum.
[0007] Furthermore, in step S2, the volume ratio of the bacterial suspensions of Bacillus belysae, Lactobacillus plantarum, and Streptomyces griseus is 5:3:2.
[0008] Furthermore, the preparation method of the modified nano-selenium composite is as follows: (1) Add chitosan to acetic acid solution and stir at room temperature for 1-2 h. Add sodium hydroxide to adjust pH to 4.5-5.5 to obtain chitosan solution. Add ferulic acid to anhydrous ethanol, then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. React at 20-30℃ in the dark for 1-2 h to obtain ferulic acid solution. Add ferulic acid solution to chitosan solution and react in a water bath at 30-50℃ for 20-26 h. Dialyze the reaction solution with deionized water for 40-50 h and freeze dry to obtain ferulic acid modified chitosan. (2) Dissolve ferulic acid-modified chitosan in deionized water, ultrasonically disperse for 20-40 min, add nano-selenium solution, stir for 20-40 min, add ascorbic acid solution, react at 50-70℃ in the dark for 5-10 h, centrifuge and wash, freeze dry to obtain modified nano-selenium complex.
[0009] Furthermore, in step (1), the ratio of chitosan, acetic acid solution, ferulic acid, anhydrous ethanol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide is 1.0-2.0g: 100-200mL: 0.5-1.0g: 50-100mL: 0.6-1.2g: 0.36-0.72g.
[0010] Furthermore, in step (2), the ratio of ferulic acid-modified chitosan, deionized water, nano-selenium solution and ascorbic acid solution is 0.2-0.4g: 50-100mL: 10-20mL: 20-40mL.
[0011] Furthermore, the biochar is obtained by pyrolyzing rice husks at 600-700℃ for 1-3 hours under oxygen-limited conditions.
[0012] Furthermore, the humic acid is humic acid extracted from weathered coal.
[0013] Furthermore, the decomposed organic matter is derived from agricultural waste, wherein the mass ratio of rice straw, livestock and poultry manure and mushroom residue is 40-50:30:20.
[0014] A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, quicklime and biochar are mixed and calcined at 500-700℃ for 1-3 hours to obtain a quicklime-biochar carrier. Microbial agents, modified nano-selenium complex, humic acid, and trehalose are premixed, added to decomposed organic matter and mixed evenly, and then mixed with the quicklime-biochar carrier. A polyvinyl alcohol solution with a mass fraction of 4-8% is sprayed in. The mixture is then granulated in a disc, dried, vacuum-sealed, and stored in the dark to obtain a compound microbial fertilizer for improving soil acidification.
[0015] The beneficial effects of this invention are: Microbial inoculants provide rice with sufficient nutrients through nitrogen fixation and phosphorus and potassium solubilization, reducing reliance on chemical fertilizers. They can also synthesize plant hormones to stimulate root development and enhance the plant's ability to absorb water and nutrients. In addition, plant lactobacillus induces rice to develop systemic resistance, improving rice's tolerance to adverse conditions such as acid rain and soil acidification, and reducing the risk of yield reduction.
[0016] Selenium is a beneficial element for rice growth. It can enhance the activity of antioxidant enzymes, remove excess reactive oxygen species in acidified soil, alleviate oxidative stress, prolong the lifespan of functional leaves in rice, and increase the accumulation of photosynthetic products. Ferulic acid, as a phenolic acid, can promote the absorption and translocation of selenium by rice roots, while inhibiting the growth of pathogens in the soil and reducing yield losses caused by diseases. Chitosan-loaded nano-selenium can slowly release selenium ions, avoiding the toxicity of excessive selenium to rice, while improving the bioavailability of selenium, ensuring that the selenium content in rice grains meets the standards, and increasing the added value of the product (selenium-enriched rice). In addition, the small particle size and large specific surface area of nano-selenium particles can adsorb toxic ions such as aluminum ions that accompany soil acidification, reducing their toxicity to rice roots and preventing further aggravation of soil acidification.
[0017] Quicklime rapidly neutralizes acidity, biochar and humic acid provide long-term buffering, and microbial metabolism dynamically regulates, forming a triple acid-regulating mechanism of "rapid-long-term-dynamic". Microorganisms solubilize phosphorus and potassium, biochar retains fertilizer, and humic acid promotes enzyme activity, constructing an efficient nutrient utilization system and reducing nutrient loss caused by acidification. Nano-selenium provides antioxidant protection, trehalose provides stress resistance, and probiotics provide disease resistance, improving the yield stability of rice in acidic soil from multiple physiological and ecological levels. Detailed Implementation
[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.
[0019] In the following examples, biochar was obtained by pyrolyzing rice husks at 600℃ for 2 hours under limited oxygen conditions; humic acid was extracted from weathered coal; and the decomposed organic matter came from agricultural waste, with the mass ratio of rice straw, livestock and poultry manure and mushroom residue being 50:30:20.
[0020] The following are examples of the preparation of microbial inoculants: S1. Bacillus belye was cultured on LB medium at 37°C and 180 rpm for 24 hours to obtain bacterial culture; Lactobacillus plantarum was cultured on MRS medium at 37°C for 36 hours to obtain bacterial culture; Streptomyces griseus was cultured on Gao's No. 1 medium at 28°C and 160 rpm for 5 days to obtain bacterial culture. S2. Mix the three bacterial cultures at a volume ratio of 5:3:2 and inoculate them into a composite culture medium (molasses 10g / L, soybean meal powder 5g / L, KH2PO4 1g / L, pH 5.5). Incubate at 30℃ and 150rpm for 3 days until the spore formation rate reaches 85%. S3. Centrifuge (4000 rpm, 15 min) to collect bacterial cells, resuspend in buffer (containing 5% trehalose and 1% skim milk), spray dry to obtain microbial inoculum (viable count ≥ 1 × 10⁻⁶). 9 CFU / g).
[0021] Example 1
[0022] A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, 9 parts quicklime and 27 parts biochar were mixed and calcined at 600℃ for 2 hours to obtain a quicklime-biochar carrier. 15 parts microbial inoculant, 0.3 parts modified nano-selenium complex, 10 parts humic acid, and 2.7 parts trehalose were premixed and mixed with 25 parts decomposed organic matter. This mixture was then mixed with the quicklime-biochar carrier and sprayed with a 6% polyvinyl alcohol solution. The mixture was then granulated in a disc (particle size 2 mm), dried at 45℃ until the moisture content was ≤8%, vacuum-sealed in aluminum foil bags, and stored away from light to obtain a compound microbial fertilizer for improving soil acidification.
[0023] Preparation of the modified selenium nanocomposite: (1) Add 1.0 g of chitosan to 100 mL of 1% acetic acid solution and stir at room temperature for 2 h. Add 1 M sodium hydroxide to adjust the pH to 5.0 to obtain chitosan solution. Add 0.5 g of ferulic acid to 50 mL of anhydrous ethanol, then add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.36 g of N-hydroxysuccinimide. React at 25 °C in the dark for 1 h to obtain ferulic acid solution. Add ferulic acid solution to chitosan solution and react in a water bath at 40 °C for 24 h. Dialyze the reaction solution with deionized water for 48 h and freeze dry to obtain ferulic acid modified chitosan. (2) Dissolve 0.2g ferulic acid modified chitosan in 50mL deionized water, sonicate for 30min, add 10mL 10mM nano selenium solution, stir for 30min, add 20mL 20mM ascorbic acid solution, react at 60℃ in the dark for 6h, centrifuge (12000rpm, 20min), wash, freeze dry to obtain modified nano selenium complex.
[0024] Example 2
[0025] A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, 8 parts quicklime and 20 parts biochar were mixed and calcined at 500℃ for 1 hour to obtain a quicklime-biochar carrier. 10 parts microbial inoculant, 0.3 parts modified nano-selenium complex, 8 parts humic acid, and 2 parts trehalose were premixed and mixed with 20 parts decomposed organic matter. This mixture was then mixed with the quicklime-biochar carrier and sprayed with a 4% polyvinyl alcohol solution. The mixture was then granulated in a disc (particle size 2 mm), dried at 45℃ until the moisture content was ≤8%, vacuum-sealed in an aluminum foil bag, and stored away from light to obtain a compound microbial fertilizer for improving soil acidification.
[0026] Preparation of the modified selenium nanocomposite: (1) Add 1.0 g of chitosan to 100 mL of 1% acetic acid solution, stir at room temperature for 1 h, add 1 M sodium hydroxide to adjust the pH to 4.5 to obtain chitosan solution; add 0.5 g of ferulic acid to 50 mL of anhydrous ethanol, then add 0.6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.36 g of N-hydroxysuccinimide, react at 20 °C in the dark for 1 h to obtain ferulic acid solution; add ferulic acid solution to chitosan solution, react in a water bath at 30 °C for 20 h, dialyze the reaction solution with deionized water for 40 h, and freeze dry to obtain ferulic acid modified chitosan; (2) Dissolve 0.2g ferulic acid modified chitosan in 50mL deionized water, sonicate for 20min, add 10mL 10mM nano selenium solution, stir for 20min, add 20mL 20mM ascorbic acid solution, react at 50℃ in the dark for 5h, centrifuge (12000rpm, 20min), wash, freeze dry to obtain modified nano selenium complex.
[0027] Example 3
[0028] A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, 10 parts quicklime and 40 parts biochar were mixed and calcined at 700℃ for 3 hours to obtain a quicklime-biochar carrier. 20 parts microbial inoculant, 0.5 parts modified nano-selenium complex, 10 parts humic acid, and 3 parts trehalose were premixed and then mixed with 30 parts decomposed organic matter. This mixture was then mixed with the quicklime-biochar carrier and sprayed with an 8% polyvinyl alcohol solution. The mixture was then granulated in a disc (particle size 2 mm), dried at 45℃ until the moisture content was ≤8%, vacuum-sealed in an aluminum foil bag, and stored away from light to obtain a compound microbial fertilizer for improving soil acidification.
[0029] Preparation of the modified selenium nanocomposite: (1) Add 2.0g of chitosan to 200mL of 1% acetic acid solution, stir at room temperature for 2h, add 1M sodium hydroxide to adjust pH to 5.5 to obtain chitosan solution; add 1.0g of ferulic acid to 100mL of anhydrous ethanol, then add 1.2g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.72g of N-hydroxysuccinimide, react at 30℃ in the dark for 2h to obtain ferulic acid solution; add ferulic acid solution to chitosan solution, react in a water bath at 50℃ for 26h, dialyze the reaction solution with deionized water for 50h, and freeze dry to obtain ferulic acid modified chitosan; (2) Dissolve 0.2g ferulic acid modified chitosan in 50mL deionized water, sonicate for 40min, add 20mL 10mM nano selenium solution, stir for 40min, add 40mL 20mM ascorbic acid solution, react at 70℃ in the dark for 10h, centrifuge (12000rpm, 20min), wash, freeze dry to obtain modified nano selenium complex.
[0030] Example 4
[0031] A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, 9 parts quicklime and 30 parts biochar were mixed and calcined at 600℃ for 2 hours to obtain a quicklime-biochar carrier. 15 parts microbial inoculant, 0.4 parts modified nano-selenium complex, 9 parts humic acid, and 2.5 parts trehalose were premixed and mixed with 25 parts decomposed organic matter. This mixture was then mixed with the quicklime-biochar carrier and sprayed with a 6% polyvinyl alcohol solution. The mixture was then granulated in a disc (particle size 2 mm), dried at 45℃ until the moisture content was ≤8%, vacuum-sealed in aluminum foil bags, and stored away from light to obtain a compound microbial fertilizer for improving soil acidification.
[0032] Preparation of the modified selenium nanocomposite: (1) Add 1.5g of chitosan to 150mL of 1% acetic acid solution, stir at room temperature for 1.5h, add 1M sodium hydroxide to adjust the pH to 5.0 to obtain chitosan solution; add 0.75g of ferulic acid to 75mL of anhydrous ethanol, then add 0.9g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.54g of N-hydroxysuccinimide, react at 25℃ in the dark for 1.5h to obtain ferulic acid solution; add ferulic acid solution to chitosan solution, react in a water bath at 40℃ for 23h, dialyze the reaction solution with deionized water for 45h, and freeze dry to obtain ferulic acid modified chitosan; (2) Dissolve 0.3g ferulic acid modified chitosan in 75mL deionized water, sonicate for 30min, add 15mL 10mM nano selenium solution, stir for 30min, add 30mL 20mM ascorbic acid solution, react at 60℃ in the dark for 7.5h, centrifuge (12000rpm, 20min), wash, freeze dry to obtain modified nano selenium complex.
[0033] Comparative Example 1 A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, 9 parts quicklime and 27 parts biochar were mixed and calcined at 600℃ for 2 hours to obtain a quicklime-biochar carrier. 15 parts microbial inoculant, 0.3 parts modified nano-selenium complex, 10 parts humic acid, and 2.7 parts trehalose were premixed and mixed with 25 parts decomposed organic matter. This mixture was then mixed with the quicklime-biochar carrier and sprayed with a 6% polyvinyl alcohol solution. The mixture was then granulated in a disc (particle size 2 mm), dried at 45℃ until the moisture content was ≤8%, vacuum-sealed in aluminum foil bags, and stored away from light to obtain a compound microbial fertilizer for improving soil acidification.
[0034] Preparation of the modified selenium nanocomposite: 0.2 g of chitosan was added to 100 mL of 1% acetic acid solution and stirred at room temperature for 2 h. Then, 10 mL of 10 mM nano-selenium solution was added and stirred for 30 min. Finally, 20 mL of 20 mM ascorbic acid solution was added and reacted at 60 °C in the dark for 6 h. The mixture was then centrifuged (12000 rpm, 20 min), washed, and freeze-dried to obtain the modified nano-selenium composite.
[0035] Comparative Example 2 A method for preparing a compound microbial fertilizer to improve soil acidification includes the following steps: By weight, 9 parts quicklime and 27 parts biochar were mixed and calcined at 600℃ for 2 hours to obtain a quicklime-biochar carrier. 15 parts microbial inoculant, 0.3 parts nano-selenium, 10 parts humic acid, and 2.7 parts trehalose were premixed and mixed with 25 parts decomposed organic matter. This mixture was then mixed with the quicklime-biochar carrier and sprayed with a 6% polyvinyl alcohol solution. The mixture was then granulated in a disc (particle size 2 mm), dried at 45℃ until the moisture content was ≤8%, vacuum-sealed in aluminum foil bags, and stored away from light to obtain a compound microbial fertilizer for improving soil acidification.
[0036] The following is a further effect test on the compound microbial fertilizer for improving soil acidification prepared by the present invention. Soil treatment: acidified paddy soil with pH 4.5 was selected, 10 kg of soil was placed in each pot, and microbial fertilizer was applied at a ratio of 0.5% before planting rice.
[0037] Measurement indicators: Soil pH: measured before sowing, during tillering, and at harvest (soil-to-water ratio 2.5:1); Rice growth: plant height, number of tillers, thousand-grain weight, and yield; Soil available selenium: measured by atomic fluorescence spectrometry. The results are as follows.
[0038] The results are recorded in Table 1; Table 1: Test Results
[0039] According to the data in Table 1, a comparison between the embodiments and comparative examples of the present invention shows that the modified nano-selenium complex significantly increases the available selenium content in the soil. The microbial fertilizer obtained in the embodiments can effectively improve soil acidification, promote plant absorption of water and nutrients, and thus increase yield.
[0040] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.
Claims
1. A compound microbial fertilizer for improving soil acidification, characterized in that, By weight, it includes the following components: 10-20 parts microbial inoculant, 0.3-0.5 parts modified nano-selenium complex, 8-10 parts quicklime, 20-40 parts biochar, 8-10 parts humic acid, 20-30 parts decomposed organic matter, and 2-3 parts trehalose.
2. The compound microbial fertilizer for improving soil acidification according to claim 1, characterized in that, The preparation method of the microbial inoculant is as follows: S1. *Bacillus belye* was cultured on LB medium at 28-37℃ and 150-200 rpm for 14-24 hours to obtain *Bacillus belye* culture; *Lactobacillus plantarum* was cultured on MRS medium at 30-37℃ for 18-36 hours to obtain *Lactobacillus plantarum* culture; *Streptomyces griseus* was cultured on Gao's No. 1 medium at 25-30℃ and 160-200 rpm for 5-7 days to obtain *Streptomyces griseus* culture. S2. Mix the three bacterial cultures and inoculate them into a composite culture medium. Culture the mixture at 25-35℃ and 120-180 rpm for 2-3 days until the spore formation rate reaches 80-90%. S3. Centrifuge to collect bacterial cells, resuspend in buffer solution, spray dry to obtain microbial inoculum.
3. The compound microbial fertilizer for improving soil acidification according to claim 2, characterized in that, In step S2, the volume ratio of the bacterial suspensions of Bacillus belysae, Lactobacillus plantarum, and Streptomyces griseus is 5:3:
2.
4. The compound microbial fertilizer for improving soil acidification according to claim 1, characterized in that, The preparation method of the modified selenium nanocomposite is as follows: (1) Add chitosan to acetic acid solution and stir at room temperature for 1-2 h. Add sodium hydroxide to adjust pH to 4.5-5.5 to obtain chitosan solution. Add ferulic acid to anhydrous ethanol, then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. React at 20-30℃ in the dark for 1-2 h to obtain ferulic acid solution. Add ferulic acid solution to chitosan solution and react in a water bath at 30-50℃ for 20-26 h. Dialyze the reaction solution with deionized water for 40-50 h and freeze dry to obtain ferulic acid modified chitosan. (2) Dissolve ferulic acid-modified chitosan in deionized water, ultrasonically disperse for 20-40 min, add nano-selenium solution, stir for 20-40 min, add ascorbic acid solution, react at 50-70℃ in the dark for 5-10 h, centrifuge and wash, freeze dry to obtain modified nano-selenium complex.
5. The compound microbial fertilizer for improving soil acidification according to claim 4, characterized in that, In step (1), the ratio of chitosan, acetic acid solution, ferulic acid, anhydrous ethanol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide is 1.0-2.0g: 100-200mL: 0.5-1.0g: 50-100mL: 0.6-1.2g: 0.36-0.72g.
6. The compound microbial fertilizer for improving soil acidification according to claim 4, characterized in that, In step (2), the ratio of ferulic acid-modified chitosan, deionized water, nano-selenium solution and ascorbic acid solution is 0.2-0.4g: 50-100mL: 10-20mL: 20-40mL.
7. The compound microbial fertilizer for improving soil acidification according to claim 1, characterized in that, The biochar is obtained by pyrolyzing rice husks at 600-700℃ for 1-3 hours under limited oxygen conditions.
8. The compound microbial fertilizer for improving soil acidification according to claim 1, characterized in that, The humic acid is extracted from weathered coal.
9. The compound microbial fertilizer for improving soil acidification according to claim 1, characterized in that, The decomposed organic matter is derived from agricultural waste, wherein the mass ratio of rice straw, livestock and poultry manure and mushroom residue is 40-50:30:
20.
10. A method for preparing a compound microbial fertilizer for improving soil acidification according to any one of claims 1-9, characterized in that, Includes the following steps: By weight, quicklime and biochar are mixed and calcined at 500-700℃ for 1-3 hours to obtain a quicklime-biochar carrier. Microbial agents, modified nano-selenium complex, humic acid, and trehalose are premixed, added to decomposed organic matter and mixed evenly, and then mixed with the quicklime-biochar carrier. A polyvinyl alcohol solution with a mass fraction of 4-8% is sprayed in. The mixture is then granulated in a disc, dried, vacuum-sealed, and stored in the dark to obtain a compound microbial fertilizer for improving soil acidification.