Compound microbial agent for tomato cultivation and matrix

Abstract

The invention relates to a compound microbial agent for tomato cultivation, the compound microbial agent comprises paenibacillus CBP-2, bacillus paralicheniformis CBJ-7 and bacillus korla CBK-5, and the invention also provides a biocontrol agent and a substrate which are prepared from the microbial agent and are used for tomato cultivation. The tomato yield can be effectively increased, the quality can be improved, solid waste resource utilization can be achieved, the production cost of the culture medium is reduced, and a foundation is laid for agricultural green sustainable development.

Description

Technical Field

[0001] The present invention relates to the technical field of resource and environmental protection, and particularly relates to a special substrate for tomato cultivation and a preparation method thereof. Background Art

[0002] With the continuous upgrading and development of agricultural planting technologies in China, soilless cultivation technology has become increasingly mature and has been widely applied to the cultivation of various organic vegetables. Tomato is one of the vegetable crops with the largest cultivation area in protected cultivation in China, effectively solving a series of problems such as continuous cropping obstacles of tomatoes, serious soil compaction, and soil-borne diseases in cultivation environments such as traditional plastic greenhouses and solar greenhouses.

[0003] In the cultivation of protected tomatoes, the selection of the substrate has an important impact on aspects such as the growth and development and yield of tomatoes. At present, in the substrate cultivation industry in China, according to raw materials, it can be divided into inorganic, organic, and mixed cultivation substrates. Commonly used inorganic substrates include ceramsite, perlite, vermiculite, etc. Although their physical and chemical properties are good, they are derived from non-renewable resources; the main materials of organic substrates are crop straws, mushroom residues, Chinese medicine residues, livestock and poultry manure, rice husks, corn cobs, biogas residues, coconut coir, etc., realizing the resource utilization of organic waste, but there are disadvantages such as being easily decomposed, resulting in a decrease in substrate volume and structural changes, as well as unstable sources and quality control. Compound substrates integrate the respective advantages of organic substrates and inorganic substrates, can be customized for specific plants or growth conditions, and have gradually become a research hotspot. In addition, before organic waste is used as a substrate material, the number and types of microorganisms in it decrease after composting treatment, the biological activity of the substrate decreases, and the nutrients that can be provided for plant growth are reduced. To ensure yield, traditional substrate cultivation usually applies excessive inorganic fertilizers, which not only increases production and management costs, but also damages the physical and chemical properties of the substrate, resulting in a decline in the quality of vegetable products and being unfavorable for sustainable development.

[0004] Research shows that adsorbing plant growth-promoting rhizobacteria in plant cultivation substrates can increase the number of microorganisms in the substrate, accelerate the microbial metabolic activities in the substrate, increase the biological activity of the substrate, promote the transformation of substances in the substrate, increase the nutrient content in the substrate, provide sufficient nutrients for plant growth, and promote plant growth. In addition, the growth-promoting bacteria themselves have the effects of preventing diseases and promoting the growth of plants, achieving rapid growth and reproduction, and improving the fruit quality and yield. By adding beneficial functional microorganisms, regulating the structure and composition of the plant rhizosphere microbial community, enhancing the metabolic activity, improving the substrate fertility, and improving the crop quality, it has a wide application prospect in future substrate improvement and green production. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite microbial agent with high efficiency in promoting growth and preventing diseases, as well as a low-cost special cultivation biocontrol preparation and substrate for tomatoes prepared from the agent.

[0006] The present invention adopts the following technical solutions: A compound microbial inoculant, which includes Paenibacillus sp. ( Paenibacillus xylanilyticus ) CBP-2, Bacillus subtilis var. licheniformis ( Bacillus paralicheniformis ) CBJ-7, and Bacillus kuerlensis ( Bacillus korlensis ) CBK-5.

[0007] Furthermore, the preservation number of Paenibacillus xylanilyticus ( Paenibacillus xylanilyticus ) CBP-2 is CGMCC No. 26727, and it is preserved in the China General Microbiological Culture Collection Center, with the address in Beijing, China, and the preservation date is March 3, 2023. This bacterium not only has the abilities of silicon release, phosphorus solubilization, potassium solubilization, siderophore production, IAA production, and cellulase production, but also has good acid and alkali tolerance and salt tolerance characteristics.

[0008] Furthermore, the preservation number of Bacillus subtilis var. licheniformis ( Bacillus paralicheniformis ) CBJ-7 is CGMCC No. 31960, and it is preserved in the China General Microbiological Culture Collection Center, with the address in Beijing, China, and the preservation date is September 13, 2024. This bacterium not only has the abilities of cellulase production and amylase production, which helps the degradation and decomposition of organic waste. Moreover, it has obvious antagonistic effects against Fusarium oxysporum f. sp. vasinfectum and Bipolaris maydis.

[0009] Furthermore, the preservation number of Bacillus kuerlensis ( Bacillus korlensis ) CBK-5 is CGMCC No. 33651, and it is preserved in the China General Microbiological Culture Collection Center, with the address in Beijing, China, and the preservation date is February 25, 2025. This strain not only has the abilities of silicon release, potassium solubilization, siderophore production, and IAA production, but also has broad-spectrum anti-plant pathogenic bacteria ability, and has antagonistic effects against Botrytis cinerea, Pseudocercospora fuligena, Fusarium oxysporum f. sp. vasinfectum, etc.

[0010] Furthermore, the ratio of the number of Paenibacillus sp. CBP-2, Bacillus subtilis var. licheniformis CBJ-7, and Bacillus kuerlensis CBK-5 is 30 - 60∶10 - 20∶30 - 50, and the total spore number or viable cell number is not less than 1×10 10 CFU / mL.

[0011] Application of the above compound microbial inoculant in preventing and treating Botrytis cinerea of tomatoes.

[0012] A biocontrol inoculant, which contains the above compound microbial inoculant, and the total spore number or viable cell number in the biocontrol inoculant is not less than 2.0×10 8 CFU / mL.

[0013] A substrate for tomato cultivation, which comprises the above-mentioned compound microbial inoculum, organic components and inorganic components; the volume ratio of the organic components to the inorganic components is 70-90:30-10.

[0014] Further, in the substrate for tomato cultivation, the total spore count or viable cell count is not less than 2.0×10 8 CFU / mL.

[0015] Further, in the substrate for tomato cultivation, the organic components include organic fertilizer and coconut coir with a volume ratio of 50-80:50-20; the organic fertilizer is obtained by anaerobic fermentation and composting of livestock and poultry manure and agricultural waste.

[0016] Further, in the substrate for tomato cultivation, the livestock and poultry manure includes pig manure, sheep manure, cow manure, and chicken manure, and the agricultural waste includes corn straw or waste mushroom bran of edible fungi.

[0017] Further, in the substrate for tomato cultivation, the organic fertilizer and coconut coir are ground into particle sizes below 5 mm.

[0018] Further, in the substrate for tomato cultivation, the inorganic components include iron tailings sand and vermiculite with a volume ratio of 30-50:70-50.

[0019] Further, in the substrate for tomato cultivation, the iron tailings sand is ground into particle sizes below 1 mm.

[0020] A preparation method of the above-mentioned substrate for tomato cultivation, which comprises the following steps: (1) Ferment Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, and Bacillus kuerlensis CBK-5 with PB liquid medium until spores are produced, count the spore content in the spore suspension, and mix them in proportion to obtain a microbial suspension; (2) Dry the organic fertilizer and coconut coir, grind them to particle sizes below 5 mm, and mix them in proportion to obtain organic components; (3) Dry the iron tailings sand and vermiculite, grind the iron tailings sand to a particle size less than 1 mm, and mix them in proportion to obtain inorganic components; (4) Mix the organic components and inorganic components evenly, adsorb the microbial suspension, so that the total spore count in the substrate is not less than 2×10 8 CFU / g.

[0021] The beneficial effects of the present invention are as follows: First, Paenibacillus sp. CBP-2 and Bacillus kuerlensis CBK-5 have the functions of silicon release, phosphorus solubilization, potassium solubilization, siderophore production, and IAA production. Applied to substrate production, they can provide nutrients for tomato growth, promote plant growth, increase tomato yield and improve quality.

[0022] Second, compound microbial agents such as Bacillus paralicheniformis CBJ-7 and Paenibacillus sp. CBP-2 have the ability to produce cellulase, amylase, protease, etc., which can promote the degradation of organic waste in the cultivation substrate and improve the utilization rate of plants.

[0023] Third, various Bacillus species in the microbial agent have good acid-base tolerance, salt tolerance and wide temperature tolerance characteristics, and can be used in substrate production to adapt to changing external environments and play a stable role.

[0024] Fourth, Bacillus kuerlensis CBK-5 has the function of inhibiting various plant pathogens such as tomato gray mold. Adding microbial agents to the substrate can effectively improve the disease prevention ability of plants and reduce the application amount of pesticides and environmental pollution.

[0025] Fifth, adding a small amount of iron tailings sand to the inorganic components not only enriches the content of various trace elements in the tomato cultivation substrate, but also improves the air permeability and water permeability of the substrate, effectively improving the soil environment.

[0026] Sixth, adding microbial agents to the substrate is beneficial to improving the micro-ecological environment of the substrate and is more conducive to the production of green and pollution-free tomato products.

[0027] Therefore, the application of microbial agents in the production of new tomato cultivation substrates has broad application prospects in terms of improving product quality and safety, as well as in new product development and environmental protection resource recycling. Description of the Drawings

[0028] Figure 1 It is the result of the strain antagonism experiment. Detailed Embodiments

[0029] The present invention will be further described below in conjunction with embodiments. The protection scope of the present invention is not limited to the embodiments, and any modifications made by those skilled in the art within the scope defined by the claims also fall within the protection scope of the present invention.

[0030] Example 1 Antagonism Experiment The preservation number of Paenibacillus sp. CBP-2 is CGMCC No. 26727, which is preserved in the China General Microbiological Culture Collection Center, located in Beijing, China, and the preservation date is March 3, 2023.

[0031] The preservation number of Bacillus paralicheniformis CBJ-7 is CGMCC No. 31960, which is preserved in the China General Microbiological Culture Collection Center, located in Beijing, China, and the preservation date is September 13, 2024.

[0032] Bacillus kuerlesensis CBK-5 was deposited under the accession number CGMCC No. 33651 at the China General Microbiological Culture Collection Center, located in Beijing, China, on February 25, 2025.

[0033] Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, and Bacillus kuerlesensis CBK-5. The three strains were cultured pairwise by the cross-streak method on a PB medium plate, and all strains grew well at the intersection, indicating that there was no mutual antagonism between the strains (see Figure 1 ).

[0034] Example 2 Preparation of a special substrate for tomato cultivation (1) Preparation of the microbial inoculant spore liquid PB liquid medium: 10 g of peptone, 5 g of beef extract, 5 g of NaCl, 1 L of distilled water, pH 7.0 - 7.2.

[0035] Using an inoculation loop, pick up some bacterial colonies of the test strains and inoculate them into the PB liquid medium. Incubate at 28 °C for 2 - 3 d, smear and observe under a microscope. When more than 80% of the bacteria produce spores, stop the incubation.

[0036] (2) Preparation of the microbial inoculant Mix Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, and Bacillus kuerlesensis CBK-5 evenly according to the spore number (or bacterial number) ratio of 50∶10∶40 to prepare a bacterial liquid with a total spore (bacterial) number not less than 1.0×10 10 CFU / mL.

[0037] (3) Preparation of a special substrate for tomato cultivation The organic components are composed of organic fertilizer and coconut coir in a volume ratio of 70∶30. The organic fertilizer is produced by aerobic fermentation and composting of pig manure + corn straw. Dry and crush the organic fertilizer and coconut coir to a particle size less than 5 mm. The inorganic components, iron tailings sand (from a certain tailings pond in Chengde, Hebei) and vermiculite (1 - 3 mm), are dried. The iron tailings sand is crushed to a particle size less than 1 mm and mixed in a volume ratio of 40∶60. Mix 80% of the organic components and 20% of the inorganic components evenly, and then adsorb the microbial inoculant and mix evenly to make the total spore (bacterial) number in the substrate not less than 2.0×10 8 CFU / g. Example 3 Same as Example 2, except that in step (2), Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, and Bacillus kuerlesensis CBK-5 are mixed evenly according to the spore number (or bacterial number) ratio of 60∶10∶30, and the total spore (bacterial) number is not less than 1.0×10 10CFU / mL. In step (3), the organic component consists of organic fertilizer and coconut coir in a volume ratio of 80:20. The organic fertilizer is produced by aerobic fermentation and composting of cow dung + waste mushroom bran. The organic fertilizer and coconut coir are dried and crushed to a particle size of less than 5 mm. The inorganic components, iron tailings sand and vermiculite, are dried. The iron tailings sand is crushed to a particle size of less than 1 mm and mixed in a volume ratio of 30:70. 90% of the organic component and 10% of the inorganic component are mixed evenly, and then the microbial inoculant is adsorbed and mixed evenly so that the total spores (bacterial count) in the substrate are not less than 2.0×10 8 CFU / g. Example 4 Same as Example 2, except that in step (2), Paenibacillus sp. CBP-2, Bacillus licheniformis subsp. CBJ-7 and Bacillus sp. CBK-5 are mixed evenly according to the spore count (or bacterial count) ratio of 40:20:40, and the total spore (bacterial cell) count is not less than 1.0×10 10 CFU / mL. In step (3), the organic component consists of organic fertilizer and coconut coir in a volume ratio of 60:40. The organic fertilizer is produced by aerobic fermentation and composting of chicken manure + corn straw + waste mushroom bran. The organic fertilizer and coconut coir are dried and crushed to a particle size of less than 5 mm. The inorganic components, iron tailings sand and vermiculite, are dried. The iron tailings sand is crushed to a particle size of less than 1 mm and mixed in a volume ratio of 50:50. 70% of the organic component and 30% of the inorganic component are mixed evenly, and then the microbial inoculant is adsorbed and mixed evenly so that the total spores (bacterial count) in the substrate are not less than 2.0×10 8 CFU / g. Example 5 Same as Example 2, except that in step (2), Paenibacillus sp. CBP-2, Bacillus licheniformis subsp. CBJ-7 and Bacillus sp. CBK-5 are mixed evenly according to the spore count (or bacterial count) ratio of 30:20:50, and the total spore (bacterial cell) count is not less than 1.0×10 10 CFU / mL. In step (3), the organic component consists of organic fertilizer and coconut coir in a volume ratio of 50:50. The organic fertilizer is produced by aerobic fermentation and composting of sheep manure + pig manure + corn straw. The organic fertilizer and coconut coir are dried and crushed to a particle size of less than 5 mm. The inorganic components, iron tailings sand and vermiculite, are dried. The iron tailings sand is crushed to a particle size of less than 1 mm and mixed in a volume ratio of 35:65. 75% of the organic component and 25% of the inorganic component are mixed evenly, and then the microbial inoculant is adsorbed and mixed evenly so that the total spores (bacterial count) in the substrate are not less than 2.0×10 8 CFU / g. Example 6 Same as Example 2, except that in step (2), Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, and Bacillus kuerlensis CBK-5 are mixed evenly according to the spore number (or cell number) ratio of 45∶15∶40, and the total spore (cell) number is not less than 1.0×10 10 CFU / mL. In step (3), the organic components are composed of organic fertilizer and coconut coir according to the volume ratio of 65∶35. The organic fertilizer is produced by aerobic fermentation and composting of sheep manure + corn straw. The organic fertilizer and coconut coir are dried and crushed to a particle size of less than 5 mm. The inorganic components, iron tailings sand and vermiculite, are dried. The iron tailings sand is crushed to a particle size of less than 1 mm and mixed according to the volume ratio of 45∶55. 85% of the organic components and 15% of the inorganic components are mixed evenly, and then adsorbed with the microbial inoculum and mixed evenly to make the total spore (cell number) in the substrate not less than 2.0×10 8 CFU / g. Example 7 Pot experiment The control effect of the compound microbial inoculum on tomato gray mold was determined by pot experiment. First, the gray mold pathogen was inoculated on solid PDA medium and cultured at 25 °C for 5 - 7 d until sporulation. Then, the spores were washed off with sterile water and the spore concentration was adjusted to 1.0×10 6 CFU / mL as the pathogen for standby. The concentrations of Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, Bacillus kuerlensis CBK-5, and the compound microbial liquid (the cell number ratio of Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7, and Bacillus kuerlensis CBK-5 is 40∶20∶40) were adjusted to 2.0×10 8 CFU / mL as the biocontrol bacterial liquid for standby.

[0038] The cultivation substrate adopted the formula of Example 2 without adding microbial inoculum. The finished tomato seedlings were transplanted into cultivation pots (the diameter of the flower pot was 23 cm and the depth was 20 cm) and the disease prevention test was carried out. The test had 6 treatments, including two control groups. One did not spray the pathogen, and the other was the water control group. There were four groups spraying the biocontrol bacterial liquid, namely 3 single bacterial liquid groups and the compound bacterial liquid group. The finished seedlings were transplanted, with 3 seedlings per pot and 10 parallels for each treatment. The bacterial liquid of each treatment was evenly sprayed on the tomato seedlings. After 7 d, the second spraying was carried out. After the second spraying for 7 d, 100 mL of a solution with a concentration of 1×10 6The spore suspension of Botrytis cinerea at [[[spores / mL]]] was evenly sprayed on the tomato leaves of each treatment until runoff, and cultured under the conditions of temperature 18°C - 25°C and humidity above 90%. After 3 days, the third spraying treatment of the biocontrol bacterial liquid was carried out, and the control group was sprayed with clear water. Seven days after the third bacterial liquid treatment, the disease incidence of the plants was counted. The grading standard for the disease incidence of tomato gray mold: Grade 0: asymptomatic; Grade 1: the diseased leaf area accounts for less than 25% of the total leaves; Grade 2: the diseased leaf area accounts for 25% - 50% of the total leaves; Grade 3: the diseased leaf area accounts for >50% - 75% of the total leaves; Grade 4: the diseased leaf area accounts for more than 75% of the total leaves; Calculate the incidence rate, and calculate the disease index and control effect according to the following formula.

[0039] Disease index = ∑ (number of diseased plants at each level × disease level) / (total number of plants surveyed × highest disease level) × 100.

[0040] Control effect (%) = (control disease index - treatment disease index) / control disease index × 100.

[0041] Table 1 Control effect of different microbial bacterial liquids on potted tomato gray mold 。

[0042] The results showed (see Table 1) that the control group without applying the microbial agent (CK + water) had full disease incidence, and many leaves of each plant showed disease spots. The disease index reached 73.50 and the incidence rate reached 100%. The incidence rate of tomato plants sprayed with the microbial bacterial liquid was significantly reduced. Among them, the incidence rate and disease index of the treatment group added with Bacillus kuerlensis CBK - 5 were significantly lower than those of CK + water, Bacillus subtilis CBJ - 7 and Paenibacillus sp. CBP - 2; while the incidence rate and disease index of tomatoes treated with the compound bacterial liquid were significantly lower than those of the control and the treatment of spraying single bacterial liquid. The incidence rate was only 36.45%, the disease index was only 20.04, and the control effect reached 72.2%. Therefore, it shows that the compound microbial bacterial liquid has a good control effect on tomato gray mold.

[0043] Example 8 Application test An application test was carried out in a greenhouse in Chengde, Hebei. The test area was 660 m 2 , and the cultivation method was strip cultivation. The distance between the ridges was 110 cm. The upper width of the cultivation trough was 30 cm, the lower width was 20 cm, the depth of the trough was 30 cm, 25 cm of substrate was filled, and the planting density was about 4000 plants per mu. The finished seedlings were transplanted. Nine treatments were set in the experiment, including 4 control groups. The substrate formula was Example 2 without adding microbial agents. The blank control CK0 did not add microbial agents, and CK1 only added Paenibacillus sp. CBP - 2 (the total number of spores or bacteria in the substrate was not less than 2.0×10 8CFU / g), CK2 was only added with Bacillus licheniformis CBJ-7 (the total number of spores or bacteria in the substrate was not less than 2.0×10 8 CFU / g), CK3 was only added with Bacillus kuerlensis CBK-5 (the total number of spores or bacteria in the substrate was not less than 2.0×10 8 CFU / g). The 5 experimental groups corresponded to the formulated substrates of Examples 2-6 respectively. Each group of experiments was set with 3 replicates, and the experimental period was 4 months. During this period, the growth of plants was observed regularly, and the tomato yields of 20 plants were randomly counted for each treatment.

[0044] Table 2 Results of the application experiment of the special substrate for tomato cultivation .

[0045] According to the Vegetable Seedling Substrate NYT2118-2012, the physical property indexes of the substrate need to meet: the bulk density is 0.2~0.6 g / cm 3 , the total porosity > 60%, and the aeration porosity > 15%. The results showed (see Table 2 for details) that the bulk density of the substrate was 0.374~0.455 g / cm 3 , the total porosity was 66.38%~68.91%, and the aeration porosity was 18.46%~21.12%, indicating that the substrate had good air permeability and oxygen supply, water retention and fertilizer retention capabilities. Whether it was the control group with single bacteria added or the experimental group with compound microbial inoculant added, the tomato yields were higher than those of the control group without bacteria added; the plant yields of each experimental group with compound microbial inoculant added were significantly better than those of the control group with single bacteria added. In addition, through the observation of the whole growth process of tomatoes, the experimental group with compound inoculant added significantly reduced the incidence of tomato diseases and improved the appearance quality of fruits (such as color, hardness, etc.), indicating that adding compound microbial inoculant to the substrate could indeed significantly promote the growth and yield of tomatoes, and at the same time reduce the application amount of chemical fertilizers and pesticides.

[0046] The present invention has been described in detail according to the above embodiments. It should be noted that the above embodiments are only for illustrative purposes of the invention. Without departing from the spirit and essence of the present invention, those skilled in the art can design various alternative and improved schemes of the present invention, which should all be understood to be within the protection scope of the present invention.

Claims

1. A composite microbial agent, characterized in that: They include Paenibacillusxylanilyticus CBP-2, Bacillus paralicheniformis CBJ-7 and Bacillus korlensis CBK-5.

2. The composite microbial agent according to claim 1, characterized in that: The deposit number of the Paenibacillus sp. CBP-2 is CGMCC No. 26727; the deposit number of the Bacillus paralicheniformis CBJ-7 is CGMCC No. 31960; and the deposit number of the Korla Bacillus sp. CBK-5 is CGMCC No. 33651.

3. The composite microbial agent according to claim 2, characterized in that: The bacterial count ratio of Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7 and Bacillus korlaensis CBK-5 was 30-60∶10-20∶30-50, and the total spore count or viable bacterial count was not less than 1×10 10 CFU / mL.

4. Use of the composite microbial agent as claimed in any one of claims 1 to 3 in preventing and controlling tomato gray mold.

5. A biocontrol agent, characterized in that: It comprises the composite microbial agent as claimed in claim 1 or 2, wherein the total spore count or viable count in the biocontrol agent is not less than 2.0×10 8 CFU / mL.

6. A substrate for tomato cultivation, characterized in that: The invention comprises the composite microbial agent as claimed in any one of claims 1 to 3, an organic component and an inorganic component; the volume ratio of the organic component to the inorganic component is 70-90:30-10.

7. The tomato cultivation substrate according to claim 6, characterized in that: The total spore count or viable bacteria count in the tomato cultivation substrate is not less than 2.0×10 8 CFU / mL.

8. The tomato cultivation substrate according to claim 6, characterized in that: The organic components include organic fertilizer and coconut bran in a volume ratio of 50-80:50-20; the organic fertilizer is obtained by anaerobic fermentation and decomposition of livestock and poultry manure and agricultural waste.

9. The tomato cultivation substrate according to claim 6, characterized in that: The inorganic components include iron tailings sand and vermiculite in a volume ratio of 30-50:70-50.

10. A method for preparing a tomato cultivation substrate according to any one of claims 6 to 9, characterized in that: It includes the following steps: (1) Fermenting Paenibacillus sp. CBP-2, Bacillus paralicheniformis CBJ-7 and Bacillus korlaensis CBK-5 in PB liquid medium until spores are produced, counting the spore content in the spore suspension, and mixing them in proportion to obtain a microbial suspension; (2) drying the organic fertilizer and coconut bran, crushing them to a particle size of less than 5 mm, and mixing them in proportion to obtain an organic component; (3) drying the iron tailings and vermiculite, crushing the iron tailings to a particle size of less than 1 mm, and mixing them in proportion to obtain an inorganic component; (4) Mix the organic and inorganic components evenly and adsorb the microbial suspension so that the total spore count in the matrix is ​​not less than 2×10 8 CFU / g.

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