Saline-alkali soil remediation fungicide and preparation method thereof

Abstract

The invention relates to the technical field of soil remediation, in particular to a saline-alkali soil remediation fungicide and a preparation method thereof. Comprising the following raw materials in parts by weight: 4 to 8 parts of bacillus subtilis, 8 to 15 parts of purple sulfur bacteria, 10 to 17 parts of rhizobium, 1 to 3 parts of bacillus megatherium, 1 to 3 parts of candida tropicalis, 1 to 3 parts of aspergillus niger, 0.05 to 0.2 part of proline, 0.5 to 2.5 parts of humic acid, 3 to 5 parts of modified charcoal, 0.1 to 0.5 part of glucose, 0.4 to 1.2 parts of monopotassium phosphate and 0.3 to 0.6 part of calcium chloride. The application of the soil remediation fungicide not only improves the growth environment of the crops, but also obviously improves the salt tolerance of the crops by adjusting the stress resistance mechanism of the crops. After the soil remediation fungicide is applied, the root system development of crops is more robust, and the density and length of the root system are obviously increased, so that the crops can absorb water and nutrients from the soil deeper layer, and the surface salt damage can be effectively resisted.

Description

Technical Field

[0001] This invention relates to the field of soil remediation agents, and more specifically, to a salinized soil remediation microbial agent and its preparation method. Background Technology

[0002] Land resources are the most fundamental and precious of all natural resources, and an irreplaceable and vital means of production in agriculture. Currently, the main method for increasing soil fertility in arable land is the application of chemical fertilizers. However, long-term, unbalanced use of chemical fertilizers has led to a decline in soil organic matter content. After prolonged and improper cultivation, farmland soil fertility decreases, permeability deteriorates, and soil compaction and cracking occur. Soil compaction reduces the soil's ability to absorb water, oxygen, and nutrients, while decreased permeability hinders root development and negatively impacts crop growth and development.

[0003] Furthermore, soil salinization can also cause soil compaction in arable land. Saline-alkali land refers to soil with excessive accumulation of salt and alkali components in the surface layer. It is characterized by high salt content and pH value, easy surface compaction, poor aeration and permeability, and low nutrient content. High salt concentrations inhibit normal crop growth. Saline-alkali land is widely distributed in my country and has become a major factor affecting the quality of arable land and restricting and jeopardizing the sustainable development of agricultural production.

[0004] The existing technology has the following problems: most microorganisms in the bacterial agents have difficulty surviving or have reduced activity in high-salt environments, resulting in poor repair effects. Summary of the Invention

[0005] This invention provides a microbial agent for the remediation of saline-alkali soil and its preparation method, which solves the technical problem that microorganisms have difficulty surviving or have reduced activity in high-salt environments, resulting in poor remediation effects.

[0006] In a first aspect, the present invention provides a microbial agent for the remediation of saline-alkali soil, comprising the following raw materials in parts by weight: 4-8 parts of Bacillus subtilis, 8-15 parts of purple sulfur bacteria, 10-17 parts of rhizobium, 1-3 parts of Bacillus megaterium, 1-3 parts of Candida tropicalis, 1-3 parts of Aspergillus niger, 0.05-0.2 parts of proline, 0.5-2.5 parts of humic acid complex, 3-5 parts of modified biochar, 0.1-0.5 parts of glucose, 0.4-1.2 parts of potassium dihydrogen phosphate, and 0.3-0.6 parts of calcium chloride.

[0007] Preferably, the humic acid complex is an iron humic acid complex.

[0008] Preferably, the modified biochar is prepared by modifying reed biochar with attapulgite.

[0009] Preferably, the Bacillus subtilis, purple sulfur bacteria, rhizobium, Bacillus megaterium, Candida tropicalis, and Aspergillus niger are respectively liquid cultured Bacillus subtilis liquid, purple sulfur bacteria liquid, rhizobium liquid, Bacillus megaterium liquid, Candida tropicalis liquid, and Aspergillus niger liquid.

[0010] Preferably, the humic acid-iron complex is prepared by adding FeCl3 powder to humic acid.

[0011] Preferably, the mass ratio of the attapulgite to the reed biochar is 2~5:1~2.

[0012] Preferably, the humic acid is selected from at least one of melanoic acid, succinic acid, and succinic acid.

[0013] Preferably, the mass ratio of humic acid to FeCl3 is 5-8:1-2.

[0014] Preferably, the preparation method of the humic acid iron complex includes the following steps: adding the FeCl3 powder and the humic acid powder to deionized water and mixing, adjusting the pH to 6-7, heating and stirring at a temperature of 60-70°C, allowing to stand, and centrifuging to obtain the humic acid iron complex.

[0015] Preferably, the Bacillus megaterium NCT-5 is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC NO.12910.

[0016] Preferably, the *Candida tropicalalis* strain is deposited at the China General Microbiological Culture Collection Center, accession number CGMCC NO. 21583.

[0017] Preferably, the Aspergillus niger is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC NO.1578.

[0018] Secondly, the present invention provides a method for preparing a microbial agent for remediating salinized soil, comprising the following steps: (1) Potassium dihydrogen phosphate and calcium chloride were added to the Bacillus subtilis liquid, purple sulfur bacteria liquid, Rhizobium liquid, Bacillus megaterium liquid, Candida tropicalis liquid and Aspergillus niger liquid, and the mixture was shaken and mixed to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze dry in vacuum for 12h to 24h to obtain freeze-dried bacterial agent.

[0019] In summary, the present invention has the following beneficial effects: 0. The humic acid complex in this invention is an iron-humic acid complex, which has a larger specific surface area, providing more attachment sites for microorganisms. It possesses abundant redox-active functional groups, higher specific capacitance and exchange current density, exhibiting stronger redox activity. Humic acid, through its strong adsorption capacity, binds to water-soluble Na⁺ in the soil, significantly reducing the sodium ion content in saline-alkali soil, thereby alleviating salt stress. Simultaneously, the humic acid component in the iron-humic acid complex can replace Na⁺ on the rhizosphere adsorption sites. + Promote Ca 2+ Enrichment enhances plant salt tolerance. Iron humate complexes stabilize iron ions (Fe³⁺) through chelation, forming water-soluble Fe-HS complexes, preventing iron from precipitating and becoming ineffective in alkaline soils. These complexes can be directly absorbed by plant roots or serve as an iron source for microorganisms, promoting iron nutrition in plants. Iron humate stimulates root H⁺-ATPase activity, enhancing the transmembrane proton gradient and promoting iron ion absorption. Simultaneously, it regulates the expression of genes related to iron absorption, improving plant adaptability under salt stress.

[0020] 2. In this invention, Bacillus megaterium, Candida tropicalis, and Aspergillus niger are added. These microorganisms often dissolve insoluble nutrients and improve soil structure by secreting metabolites such as organic acids and polysaccharides, and work synergistically with other microbial species to improve remediation stability.

[0021] 3. The application of the soil remediation microbial agent prepared in this invention not only improves the growth environment but also significantly enhances the crop's salt tolerance by regulating its stress resistance mechanism. After applying the soil remediation microbial agent, the crop's root system develops more robustly, with a significant increase in root density and length. This allows the crop to absorb water and nutrients from deeper soil layers, effectively resisting surface salt damage. Simultaneously, the microbial agent also improves the crop's photosynthetic efficiency and enhances its antioxidant capacity, thus making the plant's growth more stable under adverse conditions. Continuous application of the soil remediation microbial agent can not only gradually improve saline-alkali soil but also increase the yield and quality of economic crops.

[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of the present invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from commercially available sources.

[0024] Example Example 1 A soil salinization remediation microbial agent comprises the following raw materials in parts by weight: 4 parts Bacillus subtilis, 8 parts purple sulfur bacteria, 10 parts rhizobium, 1 part Bacillus megaterium, 1 part Candida tropicalis, 1 part Aspergillus niger, 0.05 parts proline, 3 parts modified biochar, 0.5 parts humic acid complex, 0.1 parts glucose, 0.4 parts potassium dihydrogen phosphate, and 0.3 parts calcium chloride.

[0025] Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively cultured in liquid form as Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger, with a cell count of 10. 10 cfu / mL.

[0026] Modified biochar was prepared by modifying reed biochar with attapulgite, wherein the mass ratio of attapulgite to reed biochar was 2:1.

[0027] The humic acid complex is an iron humic acid complex, which is prepared by adding FeCl3 powder to humic acid. The mass ratio of humic acid to FeCl3 is 5:1, and the humic acid is selected from the nitric acid class.

[0028] The preparation method of humic acid iron complex includes the following steps: FeCl3 powder and humic acid powder are added to deionized water in a certain mass ratio and mixed. The pH is adjusted to 7, heated and stirred at 60°C, allowed to stand, and centrifuged to obtain humic acid iron complex.

[0029] A method for preparing a microbial agent for remediating salinized soil includes the following steps: (1) Add potassium dihydrogen phosphate and calcium chloride to Bacillus subtilis solution, purple sulfur bacteria solution, Rhizobium solution, Bacillus megaterium solution, Candida tropicalis solution and Aspergillus niger solution, shake and mix to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 12 hours to obtain freeze-dried bacterial agent.

[0030] Example 2 A soil salinization remediation microbial agent comprises the following raw materials in parts by weight: 6 parts Bacillus subtilis, 12 parts purple sulfur bacteria, 15 parts rhizobium, 2 parts Bacillus megaterium, 2 parts Candida tropicalis, 2 parts Aspergillus niger, 0.15 parts proline, 4 parts modified biochar, 1.5 parts humic acid complex, 0.3 parts glucose, 0.8 parts potassium dihydrogen phosphate, and 0.4 parts calcium chloride.

[0031] Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively cultured in liquid form as Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger, with a cell count of 10. 10 cfu / mL.

[0032] Modified biochar was prepared by modifying reed biochar with attapulgite, and the mass ratio of attapulgite to reed biochar was 3:1.

[0033] The humic acid complex is an iron humic acid complex, which is prepared by adding FeCl3 powder to humic acid. The mass ratio of humic acid to FeCl3 is 7:2, and the humic acid is selected from the nitric acid class.

[0034] The preparation method of humic acid iron complex includes the following steps: FeCl3 powder and humic acid powder are added to deionized water in a certain mass ratio and mixed. The pH is adjusted to 6.5, heated and stirred at 65°C, allowed to stand, and centrifuged to obtain humic acid iron complex.

[0035] A method for preparing a microbial agent for remediating salinized soil includes the following steps: (1) Add potassium dihydrogen phosphate and calcium chloride to Bacillus subtilis solution, purple sulfur bacteria solution, Rhizobium solution, Bacillus megaterium solution, Candida tropicalis solution and Aspergillus niger solution, shake and mix to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 16 hours to obtain freeze-dried bacterial agent.

[0036] Example 3 A soil salinization remediation microbial agent comprises the following raw materials in parts by weight: 4 parts Bacillus subtilis, 9 parts purple sulfur bacteria, 11 parts rhizobium, 2 parts Bacillus megaterium, 2 parts Candida tropicalis, 2 parts Aspergillus niger, 0.15 parts proline, 4 parts modified biochar, 1.5 parts humic acid complex, 0.2 parts glucose, 0.5 parts potassium dihydrogen phosphate, and 0.5 parts calcium chloride.

[0037] Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively cultured in liquid form as Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger, with a cell count of 10. 10 cfu / mL.

[0038] Modified biochar was prepared by modifying reed biochar with attapulgite, wherein the mass ratio of attapulgite to reed biochar was 3:2.

[0039] The humic acid complex is an iron humic acid complex, which is prepared by adding FeCl3 powder to humic acid. The mass ratio of humic acid to FeCl3 is 6:1, and the humic acid is selected from the nitric acid class.

[0040] The preparation method of humic acid iron complex includes the following steps: FeCl3 powder and humic acid powder are added to deionized water in a certain mass ratio and mixed. The pH is adjusted to 7, heated and stirred at 60°C, allowed to stand, and centrifuged to obtain humic acid iron complex.

[0041] A method for preparing a microbial agent for remediating salinized soil includes the following steps: (1) Add potassium dihydrogen phosphate and calcium chloride to Bacillus subtilis solution, purple sulfur bacteria solution, Rhizobium solution, Bacillus megaterium solution, Candida tropicalis solution and Aspergillus niger solution, shake and mix to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 12 hours to obtain freeze-dried bacterial agent.

[0042] Example 4 A soil salinization remediation microbial agent comprises the following raw materials in parts by weight: 6 parts Bacillus subtilis, 13 parts purple sulfur bacteria, 16 parts rhizobium, 3 parts Bacillus megaterium, 3 parts Candida tropicalis, 3 parts Aspergillus niger, 0.1 parts proline, 5 parts modified biochar, 2.1 parts humic acid complex, 0.4 parts glucose, 0.8 parts potassium dihydrogen phosphate, and 0.5 parts calcium chloride.

[0043] Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively cultured in liquid form as Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger, with a cell count of 10. 12 cfu / mL.

[0044] Modified biochar was prepared by modifying reed biochar with attapulgite, and the mass ratio of attapulgite to reed biochar was 4:1.

[0045] The humic acid complex is an iron humic acid complex, which is prepared by adding FeCl3 powder to humic acid. The mass ratio of humic acid to FeCl3 is 7:2, and the humic acid is selected from the nitric acid class.

[0046] The preparation method of humic acid iron complex includes the following steps: FeCl3 powder and humic acid powder are added to deionized water in a certain mass ratio and mixed. The pH is adjusted to 6.5, heated and stirred at 65°C, allowed to stand, and centrifuged to obtain humic acid iron complex.

[0047] A method for preparing a microbial agent for remediating salinized soil includes the following steps: (1) Add potassium dihydrogen phosphate and calcium chloride to Bacillus subtilis solution, purple sulfur bacteria solution, Rhizobium solution, Bacillus megaterium solution, Candida tropicalis solution and Aspergillus niger solution, shake and mix to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 16 hours to obtain freeze-dried bacterial agent.

[0048] Example 5 A soil salinization remediation microbial agent comprises the following raw materials in parts by weight: 4 parts Bacillus subtilis, 10 parts purple sulfur bacteria, 12 parts rhizobium, 2 parts Bacillus megaterium, 2 parts Candida tropicalis, 2 parts Aspergillus niger, 0.15 parts proline, 3 parts modified biochar, 1.5 parts humic acid complex, 0.2 parts glucose, 0.6 parts potassium dihydrogen phosphate, and 0.5 parts calcium chloride.

[0049] Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively cultured in liquid form as Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger, with a cell count of 10. 11 cfu / mL.

[0050] Modified biochar was prepared by modifying reed biochar with attapulgite, wherein the mass ratio of attapulgite to reed biochar was 3:2.

[0051] The humic acid complex is an iron humic acid complex, which is prepared by adding FeCl3 powder to humic acid. The mass ratio of humic acid to FeCl3 is 6:1, and the humic acid is selected from the nitric acid class.

[0052] The preparation method of humic acid iron complex includes the following steps: FeCl3 powder and humic acid powder are added to deionized water in a certain mass ratio and mixed. The pH is adjusted to 7, heated and stirred at 60°C, allowed to stand, and centrifuged to obtain humic acid iron complex.

[0053] A method for preparing a microbial agent for remediating salinized soil includes the following steps: (1) Add potassium dihydrogen phosphate and calcium chloride to Bacillus subtilis solution, purple sulfur bacteria solution, Rhizobium solution, Bacillus megaterium solution, Candida tropicalis solution and Aspergillus niger solution, shake and mix to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 12 hours to obtain freeze-dried bacterial agent.

[0054] Example 6 A soil salinization remediation microbial agent comprises the following raw materials in parts by weight: 8 parts Bacillus subtilis, 15 parts purple sulfur bacteria, 17 parts rhizobium, 3 parts Bacillus megaterium, 3 parts Candida tropicalis, 3 parts Aspergillus niger, 0.2 parts proline, 5 parts modified biochar, 2.5 parts humic acid complex, 0.5 parts glucose, 1.2 parts potassium dihydrogen phosphate, and 0.6 parts calcium chloride.

[0055] Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively cultured in liquid form as Bacillus subtilis, purple sulfur bacteria, rhizobia, Bacillus megaterium, Candida tropicalis, and Aspergillus niger, with a cell count of 10. 10 cfu / mL.

[0056] Modified biochar was prepared by modifying reed biochar with attapulgite, wherein the mass ratio of attapulgite to reed biochar was 5:2.

[0057] The humic acid complex is an iron humic acid complex, which is prepared by adding FeCl3 powder to humic acid. The mass ratio of humic acid to FeCl3 is 8:1, and the humic acid is selected from the nitric acid class.

[0058] The preparation method of humic acid iron complex includes the following steps: FeCl3 powder and humic acid powder are added to deionized water in a certain mass ratio and mixed. The pH is adjusted to 7, heated and stirred at 70°C, allowed to stand, and centrifuged to obtain humic acid iron complex.

[0059] A method for preparing a microbial agent for remediating salinized soil includes the following steps: (1) Add potassium dihydrogen phosphate and calcium chloride to Bacillus subtilis solution, purple sulfur bacteria solution, Rhizobium solution, Bacillus megaterium solution, Candida tropicalis solution and Aspergillus niger solution, shake and mix to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 24 hours to obtain freeze-dried bacterial agent.

[0060] Comparative Example 1 The difference between this comparative example and Example 1 is that no humic acid complex was added.

[0061] Comparative Example 2 The difference between this comparative example and Example 1 is that the humic acid complex is replaced with black acid-based humic acid.

[0062] Comparative Example 3 The difference between this comparative example and Example 1 is that Aspergillus niger was not added.

[0063] Comparative Example 4 The difference between this comparative example and Example 1 is that Candida tropicalis was not added.

[0064] Comparative Example 5 The difference between this comparative example and Example 1 is that Bacillus megaterium was not added.

[0065] Comparative Example 6 The difference between this comparative example and Example 1 is that no modified biochar was added.

[0066] Comparative Example 7 The difference between this comparative example and Example 1 is that the modified biochar is replaced with biochar.

[0067] Comparative Example 8 The difference between this comparative example and Example 1 is that proline was not added.

[0068] Table 1 As shown in Table 1, the application of the soil remediation microbial agent prepared in Example 1 not only improved the growth environment but also significantly enhanced the crop's salt tolerance by regulating its stress resistance mechanism. The nitrate nitrogen content in the soil decreased by 28.22%, the nitrate content decreased by 28.22%, and the soil organic matter content increased by 28.5%. This demonstrates that the application of the soil remediation microbial agent not only improved the growth environment but also significantly enhanced the crop's salt tolerance by regulating its stress resistance mechanism. After applying the soil remediation microbial agent, the crop's root system developed more robustly, with a significant increase in root density and length. This enabled the crop to absorb water and nutrients from deeper soil layers, effectively resisting surface salt damage. Simultaneously, the microbial agent also improved the crop's photosynthetic efficiency and enhanced its antioxidant capacity, thus making the plant's growth more stable under adverse conditions. Continuous application of the soil remediation microbial agent can not only gradually improve saline-alkali soil but also increase the yield and quality of economic crops.

[0069] The above description is merely an exemplary embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A microbial agent for remediating salinized soil, characterized in that, The raw materials include the following parts by weight: 4-8 parts of Bacillus subtilis, 8-15 parts of purple sulfur bacteria, 10-17 parts of rhizobium, 1-3 parts of Bacillus megaterium, 1-3 parts of Candida tropicalis, 1-3 parts of Aspergillus niger, 0.05-0.2 parts of proline, 0.5-2.5 parts of humic acid complex, 3-5 parts of modified biochar, 0.1-0.5 parts of glucose, 0.4-1.2 parts of potassium dihydrogen phosphate, and 0.3-0.6 parts of calcium chloride; The humic acid complex is an iron humic acid complex, and the modified biochar is prepared by modifying reed biochar with attapulgite.

2. The salinized soil remediation microbial agent according to claim 1, characterized in that, The humic acid-iron complex was prepared by adding FeCl3 powder to humic acid; the mass ratio of attapulgite to reed biochar was 2~5:1~2.

3. The salinized soil remediation microbial agent according to claim 1, characterized in that, The Bacillus subtilis, purple sulfur bacteria, rhizobium, Bacillus megaterium, Candida tropicalis, and Aspergillus niger were respectively liquid cultured Bacillus subtilis liquid, purple sulfur bacteria liquid, rhizobium liquid, Bacillus megaterium liquid, Candida tropicalis liquid, and Aspergillus niger liquid.

4. The salinized soil remediation microbial agent according to claim 1, characterized in that, The humic acid is selected from at least one of the following: melanic acid, brown acid, and yellow acid.

5. The salinized soil remediation microbial agent according to claim 1, characterized in that, The mass ratio of humic acid to FeCl3 is 5-8:1-2.

6. The salinized soil remediation microbial agent according to claim 1, characterized in that, The preparation method of the humic acid iron complex includes the following steps: adding the FeCl3 powder and the humic acid powder to deionized water and mixing them, adjusting the pH to 6-7, heating and stirring at a temperature of 60-70°C, allowing it to stand, and centrifuging to obtain the humic acid iron complex.

7. The salinized soil remediation microbial agent according to claim 1, characterized in that, The Bacillus megaterium NCT-5 is deposited at the China General Microbiological Culture Collection Center, accession number CGMCC NO.12910.

8. The salinized soil remediation microbial agent according to claim 1, characterized in that, The aforementioned Candida tropicalalis is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC NO.21583.

9. The salinized soil remediation microbial agent according to claim 1, characterized in that, The Aspergillus niger is deposited at the China General Microbiological Culture Collection Center, accession number CGMCC NO.1578.

10. The method for preparing the salinized soil remediation microbial agent according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Potassium dihydrogen phosphate and calcium chloride were added to the Bacillus subtilis liquid, purple sulfur bacteria liquid, Rhizobium liquid, Bacillus megaterium liquid, Candida tropicalis liquid and Aspergillus niger liquid, and the mixture was shaken and mixed to obtain a bacterial suspension. (2) Add proline, modified biochar and humic acid complex to the bacterial suspension, mix evenly, and freeze-dry under vacuum for 12h to 24h to obtain freeze-dried bacterial agent.

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