Alkaline reduction and desalination functional composite microbial agent and preparation method thereof
By screening suitable combinations of salt- and alkali-tolerant functional strains and using a graded and stepwise fermentation process, combined with modified carriers and protectants, a highly active and stable composite microbial agent was prepared. This solved the problem of poor improvement effect of saline-alkali land in existing technologies and achieved comprehensive improvement and stability enhancement of saline-alkali land.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNER MONGOLIA AUTONOMOUS REGION AGRI & ANIMAL HUSBANDRY TECH PROMOTION CENT
- Filing Date
- 2026-03-11
- Publication Date
- 2026-06-23
AI Technical Summary
Existing microbial agents have weak salt and alkali tolerance, poor strain synergy, limited improvement effect, and insufficient stability of viable cell count in saline-alkali land improvement. Furthermore, the carriers cannot provide a stable colonization microenvironment, resulting in poor overall improvement effect of saline-alkali land.
By using compound functional bacterial powder, compound modified carrier and compound protectant, and by screening suitable salt and alkali tolerant functional strain combinations, combined with graded and stepwise fermentation process and vacuum freeze drying technology, a functional compound microbial agent with high viable count and stability for alkali reduction and desalination was prepared.
It achieves multiple effects such as soil alkalinity neutralization, soluble salt degradation, soil nutrient activation, and crop growth promotion, improving the overall improvement efficiency of saline-alkali land and the survival rate, colonization capacity, and batch stability of the microbial agent. It is suitable for soils with different degrees of salinization and various planting scenarios.
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Figure CN122256018A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to saline-alkali land improvement and agricultural microbial inoculant technology, specifically to a functional compound microbial inoculant for reducing alkali and desalination and its preparation method. Background Technology
[0002] Saline-alkali land is an important reserve of arable land in my country, with a total area exceeding 99 million hectares. Among these, arable land salinization is a prominent issue. High soil pH and high soluble salt content lead to soil compaction, poor aeration and permeability, and reduced nutrient availability, severely inhibiting crop seed germination and root growth, thus hindering the sustainable development of agricultural production. Microbial improvement technology, due to its advantages of being green and environmentally friendly, causing no secondary pollution, and possessing strong sustainability, has become one of the core technologies for the comprehensive management of saline-alkali land. Through the metabolic activities of functional microorganisms, multiple effects can be achieved, including soil desalination, fertility enhancement, and microecological improvement.
[0003] While existing microbial agents for improving saline-alkali land exist, their practical applications suffer from several drawbacks. Firstly, the strains in these compound agents often exhibit poor compatibility, frequently employing conventional, non-salt-tolerant functional strains. These strains suffer from low survival rates and weak colonization under high saline-alkali stress, making it difficult to sustain metabolic activity and resulting in short-lasting effects in reducing alkali and desalinizing. Secondly, the strains are often single-function, with most agents focusing solely on reducing alkali or desalinizing, failing to simultaneously achieve synergistic effects such as soil alkalinity neutralization, salt degradation, nutrient activation, and crop growth promotion, thus limiting the overall improvement of saline-alkali land. Furthermore, the carriers used in these agents are often ordinary inert carriers like peat moss and vermiculite, serving only as fillers and diluents, failing to provide a stable microenvironment for colonization of functional strains or the ability to assist in improving saline-alkali soil, making it difficult to achieve synergistic effects with functional strains. Thirdly, existing preparation processes often employ mixed fermentation for propagation, but the optimal growth conditions for different functional strains vary significantly, leading to competitive inhibition between strains and insufficient viable cell counts in some functional strains. This results in poor batch stability of the agents, hindering large-scale, stable production. Summary of the Invention
[0004] The purpose of this invention is to provide a functional composite microbial agent for reducing alkali and desalination and its preparation method, so as to solve the problems of weak salt and alkali resistance, poor strain synergy, limited improvement effect, and insufficient stability of viable cell count in existing microbial agents.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a functional compound microbial agent for reducing alkali and desalination and its preparation method, comprising compound functional bacterial powder, compound modified carrier and compound protective agent, wherein, by weight, the compound functional bacterial powder is 5-15 parts, the compound modified carrier is 75-90 parts and the compound protective agent is 3-10 parts;
[0006] The compound functional bacterial powder is composed of Bacillus subtilis powder, Bacillus mucilaginosus powder, Halophilic tetracoccus powder, Pseudomonas schrenckii powder and Rhodospirillum rubrum powder;
[0007] The composite modified carrier is composed of modified corn straw biochar, potassium humate, and modified diatomaceous earth.
[0008] The composite protective agent is composed of trehalose, glycerin, and sodium carboxymethyl cellulose.
[0009] Furthermore, in the compound functional bacterial powder, the viable count ratio of each strain is as follows: Bacillus subtilis ≥ 2.0 × 10^10 CFU / g, Bacillus mucilaginosus ≥ 1.0 × 10^10 CFU / g, Halophilic tetracoccus ≥ 1.5 × 10^10 CFU / g, Pseudomonas schlegelii ≥ 1.0 × 10^10 CFU / g, Rhodospirillum rubrum ≥ 0.5 × 10^10 CFU / g, and the total viable count of the compound functional bacterial powder is ≥ 6.0 × 10^10 CFU / g.
[0010] Furthermore, the composite modified carrier comprises 40-60 parts of modified corn straw biochar, 20-30 parts of potassium humate, and 15-30 parts of modified diatomaceous earth.
[0011] Furthermore, the modified corn stalk biochar is corn stalk biochar modified stepwise by citric acid-sodium hydroxide under oxygen-limited pyrolysis conditions; the modified diatomaceous earth is hydrochloric acid purified and modified diatomaceous earth.
[0012] Furthermore, the composite protective agent comprises 1-4 parts trehalose, 1-3 parts glycerol, and 1-3 parts sodium carboxymethyl cellulose.
[0013] Furthermore, the finished product of the bacterial agent has a moisture content of ≤20%, a pH value of 6.5-7.5, and a miscellaneous bacteria rate of ≤3%.
[0014] A method for preparing a functional compound microbial agent for reducing alkali and desalination includes the following steps:
[0015] S1. Strain activation and seed culture preparation: slant cultured strains of Bacillus subtilis, Bacillus mucilaginosus, Halophilic tetracoccus, Pseudomonas schrenckii, and Rhodospirillum rubrum were respectively inoculated into their corresponding activation media and cultured at constant temperature to obtain primary seed cultures for each strain; then, the primary seed cultures were transferred to their corresponding propagation media for secondary seed culture to obtain secondary seed cultures for each strain.
[0016] S2. Stepwise liquid submerged fermentation: Fermentation process parameters are set according to the growth characteristics of each strain. The secondary seed liquid of each strain is inoculated into the fermentation medium and liquid submerged fermentation is carried out. After the fermentation is completed, the fermentation broth of each strain is obtained.
[0017] S3. Preparation of bacterial powder: The fermentation broth of each strain is centrifuged separately, the bacterial precipitate is collected, a composite protective agent is added to the bacterial precipitate, and after stirring evenly, it is vacuum freeze-dried to obtain single bacterial powder of each strain, which is then stored in a sealed container at low temperature for later use.
[0018] S4. Preparation of composite modified carrier: Modified corn straw biochar and modified diatomaceous earth are prepared separately. Modified corn straw biochar, potassium humate and modified diatomaceous earth are weighed according to the ratio, mixed and then crushed, sieved and sterilized to obtain composite modified carrier for later use.
[0019] S5. Compound Formulation of Microbial Agent: Weigh the single-strain microbial powder according to the ratio, mix them evenly to obtain compound functional microbial powder; then add the compound functional microbial powder, compound modified carrier, and remaining compound protective agent into a double helix mixer, mix them evenly under low temperature and light-proof conditions to obtain a semi-finished microbial agent.
[0020] S6. Finished product preparation: The semi-finished microbial agent is tested, quantitatively dispensed, and sealed to obtain the finished product of the alkalinity-reducing and desalination functional compound microbial agent.
[0021] Furthermore, in step S1, the activation and propagation conditions for each strain are as follows:
[0022] Bacillus subtilis, Bacillus mucilaginosus, and Pseudomonas schlegelii were cultured on LB medium under the following activation conditions: 30-37℃ and constant temperature shaking at 150-200 rpm for 18-24 hours.
[0023] Halophilic tetracocci were cultured on a salt-tolerant fermentation medium, and the activation culture conditions were constant temperature shaking culture at 28-32℃ and 100-150rpm for 24-36h.
[0024] Deep red Rhodospirillum was cultured on a photosynthetic bacteria medium, and the activation culture conditions were 28-30℃ and anaerobic culture under light for 48-72h.
[0025] Furthermore, in step S3, the process parameters for vacuum freeze drying are: pre-freezing temperature -40℃ to -35℃, pre-freezing time 4-6h, cold trap temperature ≤ -50℃, vacuum degree ≤ 10Pa, and drying time 24-36h.
[0026] Further, in step S4, the preparation steps of the modified corn stalk biochar are as follows: the corn stalks are washed, crushed, and passed through a 40-mesh sieve, and pyrolyzed at 500-600℃ under oxygen-limited conditions for 2-3 hours to obtain raw biochar; the raw biochar is soaked in a 10% citric acid solution at a solid-liquid ratio of 1:10, shaken at 40℃ for 2 hours, filtered, washed with deionized water until neutral, and dried; the dried biochar is then soaked in a 5% sodium hydroxide solution at a solid-liquid ratio of 1:8, allowed to stand at room temperature for 12 hours, filtered, washed with deionized water until neutral, dried, and passed through an 80-mesh sieve to obtain modified corn stalk biochar;
[0027] The preparation steps of the modified diatomaceous earth are as follows: diatomaceous earth is soaked in a 15% hydrochloric acid solution with a solid-liquid ratio of 1:10, treated in a 60°C water bath for 3 hours, filtered, washed with deionized water until neutral, dried, and passed through an 80-mesh sieve to obtain modified diatomaceous earth.
[0028] Compared with the prior art, the functional compound microbial agent for reducing alkali and desalination and its preparation method provided by the present invention have the following beneficial effects:
[0029] 1. This invention selects suitable combinations of salt-tolerant functional strains. There is no antagonistic effect between the strains, and their functions are complementary and synergistic. This can simultaneously achieve multiple effects such as soil alkalinity neutralization, soluble salt degradation, soil nutrient activation, and crop growth promotion. Compared with existing technologies, this invention improves the comprehensive improvement efficiency of saline-alkali land.
[0030] 2. This invention employs a composite modified carrier system, which can provide abundant colonization sites for functional strains, construct a microenvironment resistant to saline-alkali stress, significantly improve the survival rate and colonization ability of strains in high saline-alkali soils, and extend the duration of the inoculant's effectiveness. At the same time, the carrier itself can adsorb sodium ions and other salt ions in the soil, improve the soil aggregate structure, and form a synergistic effect with the functional strains, thus improving the saline-alkali land improvement effect compared with existing technologies.
[0031] 3. The preparation method of the present invention adopts a graded and stepwise fermentation process, which can customize the optimal fermentation parameters according to the growth characteristics of different strains, avoid competitive inhibition between strains, and ensure high viable counts of each functional strain. Combined with vacuum freeze-drying process and the addition of composite protectants, the survival rate of strains during preparation, storage and application is greatly improved, and the production efficiency and batch stability of the bacterial agent are improved compared with the prior art.
[0032] 4. The microbial agent of the present invention is green and environmentally friendly, with no secondary pollution. It is simple and convenient to apply and can be adapted to soils with varying degrees of salinization, from mild to severe, as well as various planting scenarios such as field crops, cash crops, and garden seedlings. Compared with existing technologies, it improves the ease of application and adaptability to different scenarios. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.
[0034] Figure 1 This is a schematic diagram of the overall process provided for an embodiment of the present invention. Detailed Implementation
[0035] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.
[0036] As attached Figure 1 As shown:
[0037] Example 1:
[0038] This invention provides a functional compound microbial agent for reducing alkali and desalination and its preparation method, comprising compound functional bacterial powder, compound modified carrier and compound protective agent, wherein, by weight, the compound functional bacterial powder is 5-15 parts, the compound modified carrier is 75-90 parts and the compound protective agent is 3-10 parts;
[0039] The compound functional bacterial powder is composed of Bacillus subtilis powder, Bacillus mucilaginosus powder, Halophilic tetracoccus powder, Pseudomonas schrenckii powder and Rhodospirillum rubrum powder;
[0040] The viable count ratio of each strain in the compound functional bacteria powder is as follows: Bacillus subtilis ≥ 2.0 × 10^10 CFU / g, Bacillus mucilaginosus ≥ 1.0 × 10^10 CFU / g, Halophilic tetracoccus ≥ 1.5 × 10^10 CFU / g, Pseudomonas schlegelii ≥ 1.0 × 10^10 CFU / g, Rhodospirillum rubrum ≥ 0.5 × 10^10 CFU / g, and the total viable count of the compound functional bacteria powder is ≥ 6.0 × 10^10 CFU / g;
[0041] The finished product of the microbial agent has a moisture content of ≤20%, a pH value of 6.5-7.5, and a miscellaneous bacteria rate of ≤3%.
[0042] The composite modified carrier is composed of modified corn straw biochar, potassium humate, and modified diatomaceous earth.
[0043] The modified corn stalk biochar is corn stalk biochar modified stepwise by citric acid and sodium hydroxide under limited oxygen pyrolysis conditions; the modified diatomaceous earth is hydrochloric acid purified and modified diatomaceous earth.
[0044] The composite modified carrier includes 40-60 parts of modified corn straw biochar, 20-30 parts of potassium humate, and 15-30 parts of modified diatomaceous earth.
[0045] The compound protective agent is composed of trehalose, glycerin, and sodium carboxymethyl cellulose.
[0046] The compound protective agent includes 1-4 parts trehalose, 1-3 parts glycerin, and 1-3 parts sodium carboxymethyl cellulose.
[0047] Working Principle: First, staff perform the S1 strain activation and seed culture preparation steps. Based on the growth characteristics of the five functional strains, corresponding activation and propagation media are prepared. Each strain preserved on an slant is inoculated into its dedicated activation medium, and isothermal activation is completed under customized culture conditions according to the strain's characteristics, yielding the primary seed culture for each strain. Then, the primary seed culture is transferred to the corresponding propagation medium according to the inoculation amount to complete the secondary seed culture propagation, resulting in a stable secondary seed culture. The core principle of this step is that through two-stage activation and propagation, the cryogenically preserved strains gradually regain their growth activity, obtaining a seed culture with high cell concentration and strong activity. This provides high-quality strains for subsequent large-scale liquid fermentation, avoiding the problems of long fermentation cycles, poor cell activity, and insufficient fermentation stability caused by direct inoculation of preserved strains. Simultaneously, customized culture media and conditions are used to meet the different growth requirements of aerobic bacteria, salt-tolerant bacteria, and photosynthetic bacteria, ensuring that each strain can complete activation and propagation in the optimal environment.
[0048] Next, the staff performed the S2 graded and stepwise liquid deep fermentation step. Based on the growth characteristics of each strain, specific fermentation process parameters were set. The secondary seed liquid of each strain was inoculated into the corresponding fermentation medium and liquid deep fermentation was completed in an independent fermentation system. After fermentation, the viable cell count was tested and found to be up to standard, and the fermentation broth of each strain was obtained. The core principle of this step is to abandon the multi-strain mixed fermentation method in the existing technology and adopt single-strain independent fermentation. This avoids the competitive inhibition problem between different strains due to differences in growth cycle, nutritional requirements and metabolites, and ensures that each functional strain can complete the proliferation under optimal fermentation conditions. This ensures that the viable cell count of each strain's fermentation broth meets the standard after fermentation, providing high-quality raw materials for subsequent preparation of mycelial powder.
[0049] Then, the staff performed the S3 bacterial powder preparation step, separately centrifuging the fermentation broth of each strain with the required viable cell count at low temperature. Through centrifugation, solid-liquid separation was achieved, the fermentation supernatant was removed, and a high concentration of bacterial precipitate was enriched. A composite protective agent was added to the bacterial precipitate, and after stirring evenly, it was placed in a freeze-drying device and vacuum freeze-dried according to customized process parameters to prepare single-strain bacterial powders for each strain. These powders were then sealed and stored at low temperature for later use. The core principle of this step is that low-temperature centrifugation can efficiently enrich bacterial cells without damaging their activity; the composite protective agent can form a protective film on the surface of the bacterial cells during freeze-drying, preventing ice crystal formation from damaging the bacterial cell membrane; and the low-temperature vacuum freeze-drying process removes the moisture from the bacterial cells without damaging their activity, resulting in single-strain bacterial powders with high viable cell counts and strong stability. Low-temperature sealed storage can maximize the preservation of bacterial activity and avoid the decline of viable cell counts during storage.
[0050] Simultaneously with the bacterial strain propagation, staff performed the S4 composite modified carrier preparation steps. First, modified corn straw biochar and modified diatomaceous earth were prepared separately, and then the carriers were compounded according to the specified ratio. The modified corn straw biochar underwent a stepwise modification process using citric acid and sodium hydroxide. First, citric acid modification removed ash impurities from the biochar, enriching its microporous structure. Then, sodium hydroxide modification increased the oxygen-containing functional groups on the biochar surface, significantly improving the biochar's adsorption performance and bacterial colonization ability. The modified diatomaceous earth was purified and modified with hydrochloric acid to remove impurities and metal ions, improving its porosity and adsorption performance. The modified corn straw biochar, potassium humate, and modified diatomaceous earth were weighed according to the specified ratio, mixed, pulverized, sieved, and sterilized. This ensured uniform carrier particle size, facilitating subsequent uniform mixing with the bacterial powder. Simultaneously, sterilization killed any contaminating bacteria in the carrier, preventing contamination of the finished bacterial agent and ensuring the contamination rate met standard requirements. The final composite modified carrier was then ready for use.
[0051] Subsequently, the staff carried out the S5 microbial agent compounding and molding step. First, they weighed the single-strain microbial powder according to the formula ratio and mixed it evenly to obtain the compound functional microbial powder. Then, they added the compound functional microbial powder, the compound modified carrier, and the remaining compound protective agent into a double helix mixer and mixed them evenly under low temperature and light-proof conditions to obtain the microbial agent semi-finished product. The core principle of this step is that the low temperature and light-proof environment can avoid the decline of microbial activity due to temperature and light during the mixing process. The double helix mixer can ensure that the microbial powder, carrier, and protective agent are fully and evenly mixed, ensuring that the components in the finished microbial agent are evenly distributed and that the number of viable bacteria and the stability of core indicators are consistent in each batch of products.
[0052] Finally, the staff performed the S6 finished product preparation step, conducting quality testing on the semi-finished microbial agent. The testing indicators included core indicators such as viable cell count, moisture content, contamination rate, and pH value, ensuring that all indicators met the standard requirements in the claims. After passing the test, the microbial agent was quantitatively dispensed and sealed, ultimately yielding the finished product of the alkalinity-reducing and desalination functional compound microbial agent. The sealed packaging can isolate external moisture, light, and air, preventing the decline of viable cell count during storage and transportation, and ensuring the product's shelf life and field application effect.
[0053] Example 2:
[0054] As attached Figure 1 As shown:
[0055] A method for preparing a functional compound microbial agent for reducing alkali and desalination includes the following steps:
[0056] S1. Strain activation and seed culture preparation: slant cultured strains of Bacillus subtilis, Bacillus mucilaginosus, Halophilic tetracoccus, Pseudomonas schrenckii, and Rhodospirillum rubrum were respectively inoculated into their corresponding activation media and cultured at constant temperature to obtain primary seed cultures for each strain; then, the primary seed cultures were transferred to their corresponding propagation media for secondary seed culture to obtain secondary seed cultures for each strain.
[0057] S2. Stepwise liquid submerged fermentation: Fermentation process parameters are set according to the growth characteristics of each strain. The secondary seed liquid of each strain is inoculated into the fermentation medium and liquid submerged fermentation is carried out. After the fermentation is completed, the fermentation broth of each strain is obtained.
[0058] S3. Preparation of bacterial powder: The fermentation broth of each strain is centrifuged separately, the bacterial precipitate is collected, a composite protective agent is added to the bacterial precipitate, and after stirring evenly, it is vacuum freeze-dried to obtain single bacterial powder of each strain, which is then stored in a sealed container at low temperature for later use.
[0059] S4. Preparation of composite modified carrier: Modified corn straw biochar and modified diatomaceous earth are prepared separately. Modified corn straw biochar, potassium humate and modified diatomaceous earth are weighed according to the ratio, mixed and then crushed, sieved and sterilized to obtain composite modified carrier for later use.
[0060] S5. Compound Formulation of Microbial Agent: Weigh the single-strain microbial powder according to the ratio, mix them evenly to obtain compound functional microbial powder; then add the compound functional microbial powder, compound modified carrier, and remaining compound protective agent into a double helix mixer, mix them evenly under low temperature and light-proof conditions to obtain a semi-finished microbial agent.
[0061] S6. Finished product preparation: The semi-finished microbial agent is tested, quantitatively dispensed, and sealed to obtain the finished product of the alkalinity-reducing and desalination functional compound microbial agent.
[0062] In step S1, the activation and propagation conditions for each strain are as follows:
[0063] Bacillus subtilis, Bacillus mucilaginosus, and Pseudomonas schlegelii were cultured on LB medium under the following activation conditions: 30-37℃ and constant temperature shaking at 150-200 rpm for 18-24 hours.
[0064] Halophilic tetracocci were cultured on a salt-tolerant fermentation medium, and the activation culture conditions were constant temperature shaking culture at 28-32℃ and 100-150rpm for 24-36h.
[0065] Deep red Rhodospirillum was cultured on a photosynthetic bacteria medium, and the activation culture conditions were 28-30℃ and anaerobic culture under light for 48-72h.
[0066] In step S3, the process parameters for vacuum freeze drying are: pre-freezing temperature -40℃ to -35℃, pre-freezing time 4-6h, cold trap temperature ≤ -50℃, vacuum degree ≤ 10Pa, and drying time 24-36h.
[0067] In step S4, the preparation steps of the modified corn stalk biochar are as follows: the corn stalks are washed, crushed, and passed through a 40-mesh sieve, and then pyrolyzed at 500-600℃ under oxygen-limited conditions for 2-3 hours to obtain raw biochar; the raw biochar is soaked in a 10% citric acid solution at a solid-liquid ratio of 1:10, shaken at 40℃ for 2 hours, filtered, washed with deionized water until neutral, and dried; the dried biochar is then soaked in a 5% sodium hydroxide solution at a solid-liquid ratio of 1:8, allowed to stand at room temperature for 12 hours, filtered, washed with deionized water until neutral, dried, and passed through an 80-mesh sieve to obtain modified corn stalk biochar.
[0068] The preparation steps of the modified diatomaceous earth are as follows: diatomaceous earth is soaked in a 15% hydrochloric acid solution with a solid-liquid ratio of 1:10, treated in a 60°C water bath for 3 hours, filtered, washed with deionized water until neutral, dried, and passed through an 80-mesh sieve to obtain modified diatomaceous earth.
[0069] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.
Claims
1. A functional compound microbial agent for reducing alkali and desalination, characterized in that, It includes a compound functional bacteria powder, a compound modified carrier, and a compound protective agent. By weight, the compound functional bacteria powder consists of 5-15 parts, the compound modified carrier consists of 75-90 parts, and the compound protective agent consists of 3-10 parts. The compound functional bacterial powder is composed of Bacillus subtilis powder, Bacillus mucilaginosus powder, Halophilic tetracoccus powder, Pseudomonas schrenckii powder and Rhodospirillum rubrum powder; The composite modified carrier is composed of modified corn straw biochar, potassium humate, and modified diatomaceous earth. The composite protective agent is composed of trehalose, glycerin, and sodium carboxymethyl cellulose.
2. The functional compound microbial agent for reducing alkali and desalination according to claim 1, characterized in that, The viable count ratio of each strain in the compound functional bacterial powder is as follows: Bacillus subtilis ≥ 2.0 × 10^10 CFU / g, Bacillus mucilaginosus ≥ 1.0 × 10^10 CFU / g, Halophilic tetracoccus ≥ 1.5 × 10^10 CFU / g, Pseudomonas schlegelii ≥ 1.0 × 10^10 CFU / g, Rhodospirillum rubrum ≥ 0.5 × 10^10 CFU / g, and the total viable count of the compound functional bacterial powder is ≥ 6.0 × 10^10 CFU / g.
3. The functional compound microbial agent for reducing alkali and desalination according to claim 1, characterized in that, The composite modified carrier includes 40-60 parts of modified corn straw biochar, 20-30 parts of potassium humate, and 15-30 parts of modified diatomaceous earth.
4. The functional compound microbial agent for reducing alkali and desalination according to claim 3, characterized in that, The modified corn stalk biochar is corn stalk biochar modified stepwise by citric acid-sodium hydroxide under oxygen-limited pyrolysis conditions; the modified diatomaceous earth is hydrochloric acid purified and modified diatomaceous earth.
5. The functional compound microbial agent for reducing alkali and desalination according to claim 1, characterized in that, The composite protective agent comprises 1-4 parts trehalose, 1-3 parts glycerol, and 1-3 parts sodium carboxymethyl cellulose.
6. The functional compound microbial agent for reducing alkali and desalination according to claim 1, characterized in that, The finished product of the microbial agent has a moisture content of ≤20%, a pH value of 6.5-7.5, and a miscellaneous bacteria rate of ≤3%.
7. A method for preparing an alkali-reducing and desalination functional compound microbial agent, as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Activation of strains and preparation of seed culture: The slant culture strains of Bacillus subtilis, Bacillus mucilaginosus, Halophilic tetracoccus, Pseudomonas schrenckii and Rhodospirillum rubrum were respectively inoculated into the corresponding activation medium and activated at constant temperature to obtain the primary seed culture of each strain. The primary seed culture was then transferred to the corresponding propagation medium for secondary seed culture to obtain the secondary seed culture for each strain. S2. Stepwise liquid submerged fermentation: Fermentation process parameters are set according to the growth characteristics of each strain. The secondary seed liquid of each strain is inoculated into the fermentation medium and liquid submerged fermentation is carried out. After the fermentation is completed, the fermentation broth of each strain is obtained. S3. Preparation of bacterial powder: The fermentation broth of each strain is centrifuged separately, the bacterial precipitate is collected, a composite protective agent is added to the bacterial precipitate, and after stirring evenly, it is vacuum freeze-dried to obtain single bacterial powder of each strain, which is then stored in a sealed container at low temperature for later use. S4. Preparation of composite modified carrier: Modified corn straw biochar and modified diatomaceous earth are prepared separately. Modified corn straw biochar, potassium humate and modified diatomaceous earth are weighed according to the ratio, mixed and then crushed, sieved and sterilized to obtain composite modified carrier for later use. S5. Compound Formulation of Microbial Agent: Weigh the single-strain microbial powder according to the ratio, mix them evenly to obtain compound functional microbial powder; then add the compound functional microbial powder, compound modified carrier, and remaining compound protective agent into a double helix mixer, mix them evenly under low temperature and light-proof conditions to obtain a semi-finished microbial agent. S6. Finished product preparation: The semi-finished microbial agent is tested, quantitatively dispensed, and sealed to obtain the finished product of the alkalinity-reducing and desalination functional compound microbial agent.
8. The method for preparing an alkalinity-reducing and desalination functional compound microbial agent according to claim 7, characterized in that, In step S1, the activation and propagation conditions for each strain are as follows: Bacillus subtilis, Bacillus mucilaginosus, and Pseudomonas schlegelii were cultured on LB medium under the following activation conditions: 30-37℃ and constant temperature shaking at 150-200 rpm for 18-24 hours. Halophilic tetracocci were cultured on a salt-tolerant fermentation medium, and the activation culture conditions were constant temperature shaking culture at 28-32℃ and 100-150rpm for 24-36h. Deep red Rhodospirillum was cultured on a photosynthetic bacteria medium, and the activation culture conditions were 28-30℃ and anaerobic culture under light for 48-72h.
9. The method for preparing an alkalinity-reducing and desalination functional compound microbial agent according to claim 7, characterized in that, In step S3, the process parameters for vacuum freeze drying are: pre-freezing temperature -40℃ to -35℃, pre-freezing time 4-6h, cold trap temperature ≤ -50℃, vacuum degree ≤ 10Pa, and drying time 24-36h.
10. The method for preparing an alkalinity-reducing and desalination functional compound microbial agent according to claim 7, characterized in that, In step S4, the preparation steps of the modified corn stalk biochar are as follows: the corn stalks are washed, crushed, and passed through a 40-mesh sieve, and then pyrolyzed at 500-600℃ under oxygen-limited conditions for 2-3 hours to obtain raw biochar; the raw biochar is soaked in a 10% citric acid solution at a solid-liquid ratio of 1:10, shaken at 40℃ for 2 hours, filtered, washed with deionized water until neutral, and dried; the dried biochar is then soaked in a 5% sodium hydroxide solution at a solid-liquid ratio of 1:8, allowed to stand at room temperature for 12 hours, filtered, washed with deionized water until neutral, dried, and passed through an 80-mesh sieve to obtain modified corn stalk biochar. The preparation steps of the modified diatomaceous earth are as follows: diatomaceous earth is soaked in a 15% hydrochloric acid solution with a solid-liquid ratio of 1:10, treated in a 60°C water bath for 3 hours, filtered, washed with deionized water until neutral, dried, and passed through an 80-mesh sieve to obtain modified diatomaceous earth.