Biological preparation containing arbuscular mycorrhizal fungi and preparation method thereof

Abstract

The invention discloses a biological preparation containing arbuscular mycorrhizal fungi and a preparation method thereof. The biological agent comprises the following components in parts by weight: 4-5 parts of arbuscular mycorrhizal fungi, 1-3 parts of bacillus amyloliquefaciens and 1-2 parts of trichoderma harzianum. The invention also provides a preparation method of the composition. Compared with the prior art, the biological agent prepared by the invention has the effects of promoting crop growth, maintaining soil health and improving the yield and quality of agricultural products by promoting nutrient absorption, improving soil environment and improving nutrient effectiveness. Compared with a traditional preparation, the biological preparation provided by the invention is less in dosage, longer in effect and simpler and quicker to apply.

Description

Technical Field

[0001] The invention relates to the technical field of biological preparations, and in particular to a biological preparation containing arbuscular mycorrhizal fungi and a preparation method thereof. Background Art

[0002] In the field of plants, biological agents mainly play a role by promoting plant growth, enhancing stress resistance, preventing and controlling pests and diseases, and improving soil health. They have the advantages of being environmentally friendly and highly sustainable, and are an important tool for promoting sustainable agricultural development. They can promote plant growth. For example, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria can convert insoluble nutrients in the soil into forms that can be absorbed by plants, thereby improving soil fertility. At the same time, plant growth hormones secreted by certain microorganisms can stimulate root development and increase biomass. In addition, biological agents can also enhance plant stress resistance, help plants cope with adverse conditions such as drought, salinity, and low temperature, activate the plant immune system, and improve resistance to pathogens.

[0003] In terms of pest control, microbial fungicides such as Trichoderma and Bacillus subtilis can inhibit the growth of pathogens by competing for their living space or secreting antimicrobial substances. Biological agents can also improve soil health. For example, microorganisms such as Bacillus polymyxa and Lactobacillus plantarum can promote the formation of soil aggregate structure, reduce soil compaction, and increase soil aeration and water retention capacity. Compared with traditional chemical fertilizers and pesticides, biological agents are derived from nature, are pollution-free, and will not cause long-term impact on the environment after use. They are environmentally friendly and sustainable and are suitable for a variety of crops, including high-value-added fruits, vegetables and field crops. They can be applied in a variety of ways, including seed treatment, soil fertilization and field spraying.

[0004] Patent CN109182172A discloses a composite microbial agent, the ingredients of which include Bacillus subtilis, Trichoderma harzianum, Bacillus amyloliquefaciens, Bacillus laterosporus, Bacillus gelatinous, Bacillus licheniformis, Paecilomyces lilacinus, as well as coenzyme powder and sugar carrier. The formulation of the agent is scientific and reasonable, the production process is simple and the cost is low, which enhances the market competitiveness of the product. It has the functions of nitrogen fixation, phosphorus solubilization and potassium solubilization, can decompose farmyard manure, and improve fertilizer utilization. In addition, the agent can promote the growth of crop roots, early maturity, prevent premature aging, increase yield and improve quality. At the same time, it can effectively inhibit and kill pathogens, prevent insects and diseases, enhance the stress resistance and immunity of crops, and overcome the obstacles of continuous cropping. It can also loosen and improve the soil, degrade pesticide residues, increase agricultural planting benefits, and improve the ecological environment. Its application methods are diverse, which meets the needs of current soil and agricultural development.

[0005] Patent CN111807911A relates to a soil microbial regulator for enhancing plant stress resistance, which belongs to the field of crop cultivation. Its components include: 30-50 parts of coconut bran, 30-50 parts of Eucheuma, 10-30 parts of mushroom residue, 20-30 parts of guayule and 0.4-1.6 parts of composite bacterial agent. The regulator is made of discarded mushroom residue and coconut bran as raw materials, guayule and Eucheuma are added, and fermented under the action of composite bacterial agent. The fermented soil microbial regulator can optimize soil structure, improve soil microbial community, and provide continuous nutrition for crop growth. It can significantly promote crop growth, improve crop resistance to diseases and insect pests, reduce morbidity, enhance crop resistance, achieve increased production and income, and ensure high and stable yield of crops.

[0006] With the advancement of biotechnology, the application of biological agents will become more extensive and efficient. The application prospects of biological agents in the field of plants are broad. They can effectively promote plant growth, enhance stress resistance, prevent and control pests and diseases, reduce dependence on chemical fertilizers and pesticides, and promote the development of agriculture in a green and sustainable direction. At present, a single bacterial agent has limitations in increasing production and promoting growth, and when multiple bacteria are used in combination, their synergistic effects are still unstable and may not produce the desired effect in most cases. Therefore, the research and development of biological agents that can better play a synergistic role and have both increased production and stress resistance will be of great value in promoting the sustainable development of agriculture and reducing the use of chemical pesticides. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a biological preparation containing arbuscular mycorrhizal fungi and a preparation method thereof.

[0008] Arbuscular mycorrhizal fungi (AMF), Bacillus amyloliquefaciens and Trichoderma harzianum are three widely used microorganisms in agriculture. They play an important role in stimulating plant growth, improving soil structure, enhancing plant stress resistance and increasing yield.

[0009] Arbuscular mycorrhizal fungi (AMF) are a group of fungi that can form a symbiotic relationship with plant roots and can significantly improve the nutritional status and growth and development of plants. AMF increases the plant's absorption of nutrients such as phosphorus and nitrogen in the soil through its hyphae network, while improving the root morphology and enhancing the plant's stress resistance and disease resistance. In addition, AMF also participates in the interaction between plants and rhizosphere microorganisms, promoting the stability and diversity of soil microbial communities, thereby providing plants with a healthier growth environment.

[0010] Bacillus amyloliquefaciens is a biocontrol bacterium with a broad spectrum of disease resistance that can promote plant growth and enhance stress resistance through a variety of mechanisms. It inhibits the growth of pathogens by secreting antimicrobial substances (such as enzymes and secondary metabolites) and competes with pathogens for nutrients and space, thereby reducing the damage of pathogens to plants. In addition, Bacillus amyloliquefaciens can also induce resistance responses in plants, promote root development, and improve plant tolerance to adversities such as drought and salinity.

[0011] Trichoderma harzianum is a fungus widely used in biological control and soil improvement, with multiple mechanisms of action. It inhibits the growth of pathogens through competition, hyperparasitism, antibiotics and induction of plant resistance. Trichoderma harzianum can secrete enzymes such as chitinase to decompose the cell wall of pathogens, thereby killing them. In addition, it can form a protective layer on the surface of plant roots to prevent the infection of pathogens. Trichoderma harzianum can not only effectively prevent and control a variety of soil-borne diseases (such as root rot, damping-off, etc.), but also promote plant growth and improve soil fertility.

[0012] The application of these three microorganisms in agriculture has significant complementarity. When arbuscular mycorrhizal fungi (AMF), Bacillus amyloliquefaciens and Trichoderma harzianum work synergistically, they can significantly improve plant yield and stress resistance. AMF enhances the plant's absorption of nutrients such as phosphorus and nitrogen through its hyphae network and improves the soil aggregation structure; Bacillus amyloliquefaciens further improves nutrient utilization by dissolving insoluble phosphorus and potassium, and at the same time secretes plant hormones to regulate plant growth; Trichoderma harzianum inhibits pathogens by secreting antibacterial substances and chitinases, induces plant systemic resistance, and enhances plant resistance to diseases and insect pests. The present invention adopts the synergistic effect of the three to form complementarity in multiple aspects such as nutrient absorption, physiological regulation, root development and soil microecological optimization, optimize the rhizosphere microenvironment, promote healthy root growth, and enhance plant stress resistance and immunity, thereby achieving yield increase and sustainable agricultural development.

[0013] To achieve the above object, the present invention provides a biological preparation containing arbuscular mycorrhizal fungi, comprising the following components in parts by weight: 4-5 parts of arbuscular mycorrhizal fungi, 1-3 parts of Bacillus amyloliquefaciens and 1-2 parts of Trichoderma harzianum.

[0014] Furthermore, the viable count of the biological agent is greater than 1×10 11 CFU / g.

[0015] A method for preparing a biological preparation containing arbuscular mycorrhizal fungi comprises the following steps: The fungus is prepared by mixing arbuscular mycorrhizal fungi, Bacillus amyloliquefaciens and Trichoderma harzianum according to a certain ratio.

[0016] However, when microorganisms are not protected by carriers, their stability and activity are easily affected by environmental factors (such as temperature, humidity, ultraviolet rays, etc.), which not only weakens their colonization ability in the soil, but also may affect their role in promoting plant growth, thus leading to uncertainty in the yield-increasing effect. In addition, it is difficult for bacteria without carriers to be evenly distributed in the soil, and the soil adhesion is weak. They are easily washed away by water or blown away by the wind, resulting in uneven application effects. At the same time, their shelf life is significantly shortened due to the lack of carrier protection, and they are easily inactivated during storage and transportation, which limits the convenience and reliability of their practical application.

[0017] The present invention adopts modified sepiolite as a carrier to load and fix the bacterial agent. As a carrier, sepiolite has a high specific surface area and a porous structure to provide abundant attachment sites for microorganisms, which is conducive to the colonization and growth of strains. At the same time, its good adsorption performance can effectively fix nutrients, reduce loss, and improve fertilizer utilization. Sepiolite also has excellent stability and environmental adaptability, can maintain performance in a complex soil environment, and adjust the acid-base balance to create more suitable growth conditions for microorganisms and plants. It can improve soil structure, increase soil porosity and air permeability, provide a good physical environment for root growth, thereby promoting the development of the root system and enhancing the absorption capacity of plants to nutrients and water. Sepiolite can also repair soil and reduce pollution by absorbing heavy metals and harmful substances, and adjust soil pH, provide trace elements, and enhance the stress resistance of plants.

[0018] The pores of natural sepiolite are relatively narrow, resulting in a low specific surface area and limited effective sites for microbial attachment, thereby limiting its loading capacity. Therefore, the present invention modifies sepiolite by first subjecting it to an acid treatment to increase the number of pores, specific surface area, and number of surface active hydroxyl groups, and then subjecting it to a modification agent to enhance the loading and adsorption capacity.

[0019] When the modifier contains positive charges, the effect of fixing microorganisms can be further enhanced. This is because fungi and bacteria are negatively charged under most natural conditions. Therefore, after modification, when the surface is modified with positively charged functional groups, it can interact with the negative charges on the surface of microorganisms, reduce the repulsive force between the microorganisms and the carrier, and thus improve the stability of the load.

[0020] As a quaternary ammonium alkaloid, when betaine is grafted onto chitosan, its carboxyl group (-COO⁻) may bind to the amino group (-NH2) of chitosan through ionic or covalent bonds, while the quaternary ammonium group (-N⁺) is retained, making the surface of the modified chitosan more positively charged, thereby enhancing the adsorption capacity for negatively charged microorganisms. When betaine-grafted chitosan is mixed with modified sepiolite with a positive charge on the surface, this interaction is further enhanced, forming a multi-synergistic charge environment, further improving the stability of the microbial agent, and helping plants improve their stress resistance, nutrient absorption rate and crop yield.

[0021] Preferably, a biological preparation containing arbuscular mycorrhizal fungi comprises the following components in parts by weight: 4-5 parts of arbuscular mycorrhizal fungi, 1-3 parts of Bacillus amyloliquefaciens, 1-2 parts of Trichoderma harzianum, 10-20 parts of modified sepiolite, and 2-4 parts of betaine-grafted chitosan.

[0022] The preparation method of the modified sepiolite comprises the following steps: S1, mixing sepiolite with hydrochloric acid, soaking and washing until neutral, ultrasonically treating, centrifuging, washing and drying to obtain acid-activated sepiolite; S2. Dispersing sepiolite in methanol, adding a modifier, centrifuging, washing and drying after grafting to obtain modified sepiolite.

[0023] More preferably, the solid-to-liquid ratio of the sepiolite to hydrochloric acid is 1:5-10 g / mL.

[0024] More preferably, the soaking condition is 70-80° C. for 10-20 hours.

[0025] More preferably, the solid-to-liquid ratio of sepiolite to methanol is 1:20-30 g / mL.

[0026] More preferably, the mass ratio of sepiolite to modifier is 1:3-10.

[0027] More preferably, the grafting conditions are inert atmosphere, 60-70° C., and stirring for 3-6 hours.

[0028] More preferably, the modifier is one of 3-aminopropyltriethoxysilane, N,N-dimethylaminopropyl (triethoxy) silane or 3-triethoxysilylpropyltrimethylammonium chloride.

[0029] More preferably, the method for preparing the modified sepiolite comprises the following steps: S1. Mix sepiolite with 2-3 mol / L hydrochloric acid at a solid-liquid ratio of 1:5-10 g / mL, 70-80°C, soak for 10-20 hours, then wash to neutrality, ultrasonically treat, centrifuge, wash, and dry to obtain acid-activated sepiolite; S2. Disperse sepiolite in methanol at a solid-liquid ratio of 1:20-30 g / mL, add 3-aminopropyltriethoxysilane, and the mass ratio of sepiolite to modifier is 1:3-10. Stir for 3-6 hours at 60-70°C in an inert atmosphere, centrifuge, wash, and dry to obtain modified sepiolite.

[0030] Preferably, a method for preparing a biological preparation containing arbuscular mycorrhizal fungi comprises the following steps: The invention is obtained by mixing arbuscular mycorrhizal fungi, bacillus amyloliquefaciens, trichoderma harzianum, modified sepiolite and betaine grafted chitosan according to a certain proportion.

[0031] Beneficial effects of the present invention: 1. Compared with the prior art, the biological agent of the present invention can improve the efficiency of plants in utilizing the existing nutrients in the soil. A single application can continuously improve the soil ecology throughout the growing season or even for many years. The clump mycorrhizal fungi can also improve the soil structure and health, which can not only promote crop growth, but also improve the quality of agricultural products.

[0032] 2. Microbial preparations such as arbuscular mycorrhizal fungi (AMF) can not only improve the absorption of soil nutrients by crops, but also promote the balance of rhizosphere microorganisms, enhance crop resistance, reduce soil-borne diseases, and reduce dependence on chemical pesticides. In the fields of organic agriculture and green food production, AMF is a key input, providing a new path for sustainable agricultural development. DETAILED DESCRIPTION

[0033] Arbuscular mycorrhizal fungi, the embodiment of the present invention uses Rhizophagus intraradices numbered BGC BJ09, which comes from the arbuscular mycorrhizal fungi germplasm resource bank of Beijing Academy of Agriculture and Forestry Sciences; the number of viable bacteria after activation, expansion culture, separation, and freeze-drying is greater than 1×10 6 CFU / g.

[0034] Bacillus amyloliquefaciens, CGMCC1.857, a commercial product, is sourced from the China General Microorganism Collection Center; the number of viable cells after activation, expansion culture, separation, and freeze-drying is >5×10 10 CFU / g.

[0035] Trichoderma harzianum, CGMCC5.1213, commercially available product, sourced from China General Microorganism Collection Center; after activation, expansion culture, separation, and freeze-drying, the number of viable cells was > 5 × 10 10 CFU / g.

[0036] Sepiolite, 325 mesh, sourced from Hebei Zongrun Mineral Products Co., Ltd.

[0037] Betaine grafted chitosan is prepared by adding 10 g of chitosan to 200 mL of dilute hydrochloric acid at pH = 5, then adding 4.78 g of betaine, 5.9 g of EDC‧HCl, and 3.6 g of N-hydroxysuccinimide, heating to 55°C and stirring for 24 hours, then centrifuging to remove the precipitate, dialyzing, and freeze-drying.

[0038] Example 1 A method for preparing a biological preparation containing arbuscular mycorrhizal fungi comprises the following steps: The fungus is prepared by mixing 4.5 parts by weight of arbuscular mycorrhizal fungi, 2 parts by weight of Bacillus amyloliquefaciens and 1.5 parts by weight of Trichoderma harzianum.

[0039] Example 2 A method for preparing a biological preparation containing arbuscular mycorrhizal fungi comprises the following steps: The obtained product is prepared by mixing 4.5 parts by weight of arbuscular mycorrhizal fungi, 2 parts by weight of Bacillus amyloliquefaciens, 1.5 parts by weight of Trichoderma harzianum, 15 parts by weight of modified sepiolite and 3 parts by weight of betaine grafted chitosan.

[0040] The preparation method of the modified sepiolite comprises the following steps: S1, mixing sepiolite with 2.5 mol / L hydrochloric acid at a solid-liquid ratio of 1:8 g / mL, 75°C, soaking for 15 hours and then washing to neutrality, centrifuging after ultrasonic treatment, washing, and drying to obtain acid-activated sepiolite; S2. Disperse sepiolite in methanol at a solid-liquid ratio of 1:25 g / mL, add 3-aminopropyltriethoxysilane, and the mass ratio of sepiolite to 3-aminopropyltriethoxysilane is 1:6. Stir for 5 h at 65° C. in a nitrogen atmosphere, then centrifuge, wash, and dry to obtain modified sepiolite.

[0041] Example 3 It is basically the same as Example 2, the only difference being that 3-aminopropyltriethoxysilane is replaced by N,N-dimethylaminopropyl (triethoxy) silane.

[0042] Example 4 The method is substantially the same as Example 2, except that 3-aminopropyltriethoxysilane is replaced by 3-triethoxysilylpropyltrimethylammonium chloride.

[0043] Comparative Example 1 A method for preparing a biological preparation containing arbuscular mycorrhizal fungi comprises the following steps: The fungus is prepared by mixing 4.5 parts by weight of arbuscular mycorrhizal fungi and 2 parts by weight of Bacillus amyloliquefaciens.

[0044] Comparative Example 2 A method for preparing a biological preparation containing arbuscular mycorrhizal fungi comprises the following steps: The fungus is prepared by mixing 4.5 parts by weight of arbuscular mycorrhizal fungi and 1.5 parts by weight of Trichoderma harzianum.

[0045] Comparative Example 3 A method for preparing a biological agent comprises the following steps: The obtained product is prepared by mixing 2 parts by weight of Bacillus amyloliquefaciens and 1.5 parts by weight of Trichoderma harzianum.

[0046] Comparative Example 4 It is basically the same as Example 2, the only difference being that the modified sepiolite is replaced by sepiolite.

[0047] Comparative Example 5 It is basically the same as Example 4, the only difference being that the betaine-grafted chitosan is replaced by chitosan.

[0048] Comparative Example 6 It is basically the same as Example 4, the only difference being that the betaine grafted chitosan is replaced by 1.5 parts of betaine and 1.5 parts of chitosan.

[0049] Test Example 1 The biological preparations prepared in the embodiments and control examples were subjected to indoor growth promotion experiments, and the cucumber seeds were surface disinfected: the seeds were soaked in a 10% hydrogen peroxide solution for 10 minutes, then rinsed with sterile water and dried for later use. Ten seeds were sown in each nutrient pot and normal watering management was performed. After 4 weeks, the well-grown root seedlings were transplanted into plastic cups, and each cup was filled with 200g of sterilized soil and 10g of the biological preparation in the embodiments or control examples to ensure smooth inoculation. During transplanting, plants with consistent growth were selected for the experiment, and 48 seedlings were treated in each group and randomly placed. The treatment without biological preparation was used as a control. Each group of experiments was repeated 3 times. After 30 days of transplanting, the biomass of the cucumber plants was measured.

[0050] Table 1 Results of indoor growth promotion experiment

[0051] Arbuscular mycorrhizal fungi can form a symbiotic relationship with the cucumber root system, significantly promoting the growth and disease resistance of cucumber. In addition, AMF can also increase the content of nutrients such as soluble sugar, vitamin C, nitrogen, phosphorus, and potassium in cucumber fruits, improving fruit quality. Bacillus amyloliquefaciens can directly or indirectly promote plant growth by secreting substances such as plant hormones and antibiotics. Studies have shown that Bacillus amyloliquefaciens can increase the seed germination rate, root vitality and chlorophyll content of cucumbers, thereby promoting plant growth. In addition, it can also improve the rhizosphere soil environment and increase the content of available nitrogen, phosphorus, and potassium in the soil. Trichoderma harzianum can inhibit pathogens through heavy parasitism and secretion of antibacterial substances, thereby enhancing the disease resistance of plants. In addition, Trichoderma harzianum can also reduce root damage after pathogen infection by enhancing the antioxidant capacity of plants.

[0052] As can be seen from Table 1, compared with the examples and the control examples and the blank control group, the growth of cucumber is significantly better, which shows that the biological agent can significantly stimulate growth and activate the soil. Compared with the control examples 1-2, the three bacteria in Example 1 are used in synergy, and a better growth-promoting effect is achieved than in the control examples 1-2. This may be due to the synergistic effect of arbuscular mycorrhizal fungi (AMF), Bacillus amyloliquefaciens and Trichoderma harzianum, which can significantly improve plant yield and stress resistance. AMF enhances the absorption of nutrients such as phosphorus and nitrogen by plants through its hyphae network and improves the soil aggregation structure; Bacillus amyloliquefaciens further improves nutrient utilization by dissolving insoluble phosphorus and potassium, and secretes plant hormones to regulate plant growth; Trichoderma harzianum inhibits pathogens by secreting antibacterial substances and chitinase, induces plant systemic resistance, and enhances plant resistance to diseases and insect pests. Example 1 adopts the synergistic effect of the three, complementing each other in multiple aspects such as nutrient absorption, physiological regulation, root development and soil microecological optimization, optimizing the rhizosphere microenvironment, and promoting healthy root growth, thus achieving better results.

[0053] Compared with Example 1, Examples 2 to 4 additionally added modified sepiolite, and achieved better results. This may be because when microorganisms are not protected by a carrier, they have poor tolerance to environmental factors (such as temperature, humidity, ultraviolet rays, etc.), and the stability and activity of live bacteria are easily reduced, resulting in weakened colonization ability in the soil and unstable yield-increasing effect. In Examples 2 to 4, modified sepiolite is used as a carrier to load and fix the bacterial agent. As a carrier, sepiolite has a high specific surface area and porous structure to provide abundant attachment sites for microorganisms, which is conducive to the colonization and growth of strains. At the same time, its good adsorption performance can effectively fix nutrients, reduce loss, and improve fertilizer utilization. Sepiolite also has excellent stability and environmental adaptability, can maintain performance in complex soil environments, and adjust acid-base balance to create more suitable growth conditions for microorganisms and plants. It can improve soil structure, increase soil porosity and aeration, and provide a good physical environment for root growth, thereby promoting root development and enhancing the plant's ability to absorb nutrients and water. Sepiolite can also adsorb heavy metals and harmful substances, repair soil, reduce pollution, and adjust soil pH, provide trace elements, and enhance plant resistance. Thus, Examples 2 to 4 can achieve better results than Example 1.

[0054] Compared with Examples 2-3, Example 4 uses a modifier containing positive charge, and thus can further enhance the effect of fixing microorganisms. This is because fungi and bacteria are negatively charged under most natural conditions. Therefore, after modification, when the surface is modified with positively charged functional groups, it can interact with the negative charge on the surface of the microorganism, reducing the repulsive force between the microorganism and the carrier, thereby improving the stability of the load and allowing the replicated bacterial agent to play a better role.

[0055] Compared with control examples 5 to 6, Example 4 uses betaine grafted chitosan. Betaine is a quaternary ammonium alkaloid, and the molecule contains equal amounts of cations and anions, and is electrically neutral as a whole. When it is grafted with chitosan, the carboxyl group and the amino group are combined, so that only the quaternary ammonium salt group is left on the surface of the chitosan, which is positively charged and interacts with the negative charge on the surface of the microorganism. When the betaine grafted chitosan is mixed with the modified sepiolite with a positive charge on the surface, this interaction is further enhanced, thereby forming a multiple synergistic charge environment, further improving the stability of the microbial agent, and helping plants improve their stress resistance and nutrient absorption rate, so that the growth of the plants is significantly better.

[0056] Test Example 2 The biological preparations prepared in the embodiments and control examples were subjected to a field yield-increasing experiment. The tomatoes were surface-sterilized with 10% hydrogen peroxide for 10 minutes, washed with sterile water, and air-dried for later use. Ten seeds were sown in each nutrient pot. After 4 weeks of normal watering management, the seedlings with uniform growth were transplanted to the field greenhouse. During transplanting, the biological preparation was applied to the roots of the crops at 30 g / plant. With clean water treatment as the control, 48 seedlings were treated in each group, randomly placed, and repeated three times. After 80 days, the number of tomato fruits was measured and the yield and other biomass were calculated. See Table 2 for details.

[0057] Table 2 Field yield increase experiment results

[0058] Arbuscular mycorrhizal fungi form a symbiotic relationship with tomato roots, enhancing the root system's ability to absorb nutrients (such as phosphorus, potassium, etc.) and water. Inoculation with mycorrhizal fungi can improve seedling survival rate and adaptability after transplanting, promote root development, and thus increase the number of fruits and yields. Bacillus amyloliquefaciens can secrete plant hormones (such as indoleacetic acid) and antibiotics, promote tomato root development, and enhance the plant's disease resistance and stress resistance. In addition, it can also improve the effectiveness of nutrients in the soil through nitrogen fixation, phosphorus solubilization, potassium solubilization, etc., thereby indirectly promoting tomato growth. Trichoderma harzianum can inhibit pathogens through heavy parasitism and secretion of antibacterial substances, thereby reducing the occurrence of diseases. In addition, Trichoderma harzianum can also induce systemic resistance in tomato plants and enhance their tolerance to adversity.

[0059] As can be seen from Table 2, Example 1 has a better yield-increasing effect than the control example. This may be because when these three bacteria are used in combination, they can play a synergistic role and further improve the yield and quality of tomatoes. AMF enhances the root system's ability to absorb nutrients, while Bacillus amyloliquefaciens and Trichoderma harzianum further promote plant growth by improving the soil environment and increasing nutrient availability. The biocontrol effect of Trichoderma harzianum combined with the symbiotic advantage of AMF can significantly reduce the incidence of diseases.

[0060] Compared with Examples 1 to 3, Example 4 uses a modifier with a positive charge to modify the sepiolite. Compared with Example 1 without adding the modified sepiolite, Example 4 has a better effect of fixing microorganisms, thereby increasing the stability of the biological agent. After the surface of the modified sepiolite in Example 4 is modified with positively charged functional groups, it can interact with the negative charge on the surface of the microorganism, reduce the repulsive force between the microorganism and the carrier, thereby improving the stability of the load, so that the loaded bacterial agent can play a better role.

[0061] Compared with control examples 5 to 6, Example 4 uses betaine grafted chitosan. Compared with chitosan or simple blending, betaine chitosan not only has better solubility, but can also cooperate with positively charged sepiolite, thereby showing better microbial protection effect and growth promotion effect, and thus can significantly improve crop yield and quality.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biological preparation containing arbuscular mycorrhizal fungi, characterized in that: The invention comprises the following components in parts by weight: 4-5 parts of arbuscular mycorrhizal fungi, 1-3 parts of bacillus amyloliquefaciens and 1-2 parts of trichoderma harzianum.

2. The biological preparation containing arbuscular mycorrhizal fungi according to claim 1, characterized in that: The viable count of the biological agent is > 1×10 11 CFU / g.

3. The biological preparation containing arbuscular mycorrhizal fungi according to claim 1, comprising the following components in parts by weight: 4-5 parts of arbuscular mycorrhizal fungi, 1-3 parts of Bacillus amyloliquefaciens, 1-2 parts of Trichoderma harzianum, 10-20 parts of modified sepiolite and 2-4 parts of betaine grafted chitosan.

4. The biological preparation containing arbuscular mycorrhizal fungi according to claim 3, characterized in that: The preparation method of the modified sepiolite comprises the following steps: S1, mixing sepiolite with hydrochloric acid, soaking and washing until neutral, ultrasonically treating, centrifuging, washing and drying to obtain acid-activated sepiolite; S2. Dispersing sepiolite in methanol, adding a modifier, centrifuging, washing and drying after grafting to obtain modified sepiolite.

5. The biological preparation containing arbuscular mycorrhizal fungi according to claim 4, characterized in that: The solid-to-liquid ratio of the sepiolite to hydrochloric acid is 1:5-10 g / mL.

6. The biological preparation containing arbuscular mycorrhizal fungi according to claim 4, characterized in that: The soaking conditions are 70~80℃ and soaking for 10~20h.

7. The biological preparation containing arbuscular mycorrhizal fungi according to claim 4, characterized in that: The solid-liquid ratio of sepiolite to methanol is 1:20~30g / mL.

8. The biological preparation containing arbuscular mycorrhizal fungi according to claim 4, characterized in that: The mass ratio of sepiolite to modifier is 1:3~10; the grafting conditions are inert atmosphere, stirring at 60~70℃ for 3~6h.

9. The biological preparation containing arbuscular mycorrhizal fungi according to claim 4, characterized in that: The modifier is one of 3-aminopropyltriethoxysilane, N,N-dimethylaminopropyl (triethoxy) silane or 3-triethoxysilylpropyltrimethylammonium chloride.

10. The method for preparing a biological agent containing arbuscular mycorrhizal fungi according to any one of claims 3 to 9, characterized in that: The steps include: The invention discloses a novel chitosan composition comprising arbuscular mycorrhizal fungi, bacillus amyloliquefaciens, trichoderma harzianum, modified sepiolite and betaine grafted chitosan.

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