A selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi and a preparation method thereof

Abstract

The application discloses a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi and a preparation method thereof, and belongs to the technical field of fertilizers.The arbuscular mycorrhizal fungi and selenium elements are effectively combined in the application, the symbiotic relationship of mycorrhiza is utilized to improve the bioavailability of selenium, a multi-form selenium source system combining selenium-rich straw, selenium-rich poultry manure and selenium-rich yeast is used to change waste into treasure, the use of selenium fertilizer is reduced, the production cost is lowered, and the selenium absorption and transport capacity of arbuscular mycorrhizal fungi is relied on to improve the bioavailability of selenium in cooperation with humic acid, so that the selenium content of edible parts of crops can be significantly improved, efficient selenium biofortification can be realized, and selenium-rich agricultural products can be produced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microbial fertilizers, in particular to a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungus agent and a preparation method thereof. BACKGROUND

[0002] Selenium is one of the essential trace elements for human body, which has important physiological functions such as antioxidant, anti-tumor and immune enhancement. In most areas of China, the soil is selenium-deficient, resulting in a generally low selenium content in agricultural products, which is difficult to meet the nutritional needs of human body for selenium. The traditional application of selenium fertilizer has problems such as low utilization rate, easy loss and environmental pollution.

[0003] Arbuscular mycorrhizal fungi are an important group of soil microorganisms that can form a mutualistic symbiotic relationship with plant roots. They can significantly expand the absorption area of plant roots through the mycelial network, and improve the absorption and utilization efficiency of plants for nutrients and water. Studies have shown that arbuscular mycorrhizal fungi have good enrichment and transformation capacity for selenium elements, and can promote the absorption and metabolism of plants for selenium.

[0004] Arbuscular mycorrhizal fungi can form a symbiotic relationship with plant roots, providing the required nutrients for plants through the formation of mycorrhizal structures, while enhancing the stress resistance of plants. Arbuscular mycorrhizal fungal agents can exist in different forms, spores can germinate into mycelium under suitable environmental conditions, and further contact with plant roots to form mycorrhizal structures; mycelium has a large surface area and can expand in the soil, better absorbing nutrients in the soil and transferring them to plant roots to form a symbiotic relationship with plant roots; infected plant root segments can exist as a form of arbuscular mycorrhizal fungal agents, promoting the growth and development of plants, and can increase crop yield and quality, and reduce the amount of chemical fertilizers used.

[0005] Chinese patent document CN115286447A discloses a selenium-rich bio-organic fertilizer and a preparation method thereof, which comprises the following steps: (1) mixing and fermenting livestock and poultry manure with plant straw to obtain an organic fertilizer substrate; (2) mixing and fermenting the organic fertilizer substrate with a microbial agent, a selenium salt, sodium carbonate, potassium citrate, disodium DETA, and sodium tripolyphosphate to obtain a selenium-rich bio-organic fertilizer. The selenium-rich bio-organic fertilizer provided by the present application has a significant promoting effect on improving rice yield and the ability of rice to enrich selenium. It significantly improves the absorption and utilization rate of selenium salt in the fertilizer, achieving the purpose of scientific selenium enrichment and effective selenium supplementation. The present application mainly uses inorganic selenium compounds, which have low bioavailability and safety hazards; and the bio-fertilizer product lacks effective utilization of selenium elements, and the function is relatively single. Therefore, it is of great practical significance to develop a composite fertilizer that effectively combines selenium nutrition and microbial activity. SUMMARY

[0006] The main purpose of the present application is to provide a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi and a preparation method thereof, the arbuscular mycorrhizal fungi and selenium elements are effectively combined in the present application, the symbiotic relationship of mycorrhizae is utilized to improve the bioavailability of selenium, and the selenium content in edible parts of crops can be significantly improved and the growth of crops can be promoted.

[0007] To achieve the above-mentioned purpose, the present application provides a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi, which comprises the following components by weight: 30-50 parts of selenium-rich straw, 35-50 parts of selenium-rich poultry manure, 5-10 parts of perlite, 1-3 parts of selenium-rich yeast, 5-10 parts of modified montmorillonite, 5-15 parts of humic acid, 5-10 parts of arbuscular mycorrhizal fungi, 1-3 parts of bacillus subtilis and 3-5 parts of glucose.

[0008] The arbuscular mycorrhizal fungi and selenium elements are effectively combined in the present application, the symbiotic relationship of mycorrhizae is utilized to improve the bioavailability of selenium, the multi-form selenium source system combined with selenium-rich straw, selenium-rich poultry manure and selenium-rich yeast is a waste-to-resource system, the use of selenium fertilizer is reduced, the production cost is reduced, and the selenium bioavailability is improved by relying on the strong selenium absorption and transport capacity of arbuscular mycorrhizal fungi and humic acid, the selenium content in edible parts of crops can be significantly improved, efficient selenium biofortification can be achieved, and selenium-rich agricultural products can be produced.

[0009] Preferably, the preparation method of the modified montmorillonite is as follows:

[0010] (1) zinc chloride and 2,5-dihydroxyterephthalic acid are added to N,N-dimethylformamide, mixed uniformly, then montmorillonite is added, uniformly dispersed, heated for a period of time, and then EDC and NHS are added, and the heating reaction is continued to obtain activated montmorillonite;

[0011] (2) 2-amino-3-carboxy-1,4-naphthoquinone is dissolved in N,N-dimethylformamide, and the activated montmorillonite is added, and the temperature is raised to react to obtain a montmorillonite-naphthoquinone compound;

[0012] (3) the montmorillonite-naphthoquinone compound is dispersed in dimethyl sulfoxide, 2-hydroxypropyl-β-cyclodextrin and p-toluenesulfonic acid are added, and the reaction is stirred to obtain modified montmorillonite.

[0013] Preferably, the mass ratio of zinc chloride, 2,5-dihydroxyterephthalic acid and montmorillonite in step (1) is 5-8:3-6:15-20, the heating reaction temperature is 100-120 DEG C, and the reaction time is 6-10 h.

[0014] Montmorillonite is a good water-retaining material. In this step, by loading the zinc-based MOF material on the surface of montmorillonite, on the one hand, the specific surface area of montmorillonite is increased, and a multi-level pore structure is formed, which can provide more habitat and colonization space for microbial strains, effectively prevent the strains from falling off, and the bacterial activity and bacterial density in unit volume are higher than those of free active bacteria. High-density arbuscular mycorrhizal fungi form a more developed mycelial network, which can greatly expand the effective absorption area of plant roots. Mycelium can extend to the micro area of soil that root hairs cannot reach, actively search for and capture selenium in soil, and transport selenium to plant body through the symbiotic transport system of mycelium-root system, which can fully utilize various forms of selenium source in fertilizer, improve the bioavailability of selenium, and provide active hydroxyl and carboxyl groups. The carboxyl group is activated by NHS and EDC, which is conducive to subsequent reactions and improves the complexing sites of montmorillonite for selenium and trace elements, and gradually releases them for plant absorption.

[0015] Preferably, the mass ratio of 2-amino-3-carboxyl-1,4-naphthoquinone to activated montmorillonite in step (2) is 2-3:3-5; the reaction temperature is 60-80°C, and the reaction time is 5-8h.

[0016] In this step, 2-amino-3-carboxyl-1,4-naphthoquinone is introduced onto the surface of activated montmorillonite. The introduction of quinone structure can promote the redox metabolism of strains, secrete more substances that can promote the decomposition of selenium-rich straw and selenium-rich poultry manure, accelerate the composting temperature rise and organic matter degradation process, and gradually decompose the organic selenium compounds in selenium-rich straw and selenium-rich poultry manure, release more available selenium forms, reduce the loss of nutrient elements, and improve the utilization rate of selenium. At the same time, it can also provide active carboxyl groups for subsequent reactions.

[0017] Preferably, the mass ratio of montmorillonite-naphthoquinone complex, 2-hydroxypropyl-β-cyclodextrin, and p-toluenesulfonic acid in step (3) is 5-10:4-6:0.1-0.5.

[0018] In this step, 2-hydroxypropyl-β-cyclodextrin is bonded to the montmorillonite-naphthoquinone complex. On the one hand, it can improve the water-retaining performance of modified montmorillonite, which can continuously provide water for microorganisms and plant roots under drought conditions. At the same time, the slow release process of water can drive the synchronous release of nutrient elements, realizing the coordinated supply of water and nutrients. In addition, it can also improve the adsorption of modified montmorillonite to microbial agents and the loading of organic small molecules, N, P, K, and other nutrient elements in the soil environment and trace elements such as selenium, reducing the loss of fertilizer nutrients and meeting the nutritional needs of plant growth. At the same time, the loaded nutrient elements provide sufficient nutrient sources for microorganisms, promoting the proliferation and activity maintenance of microorganisms, and meeting the diversified nutritional needs of crops during the growth period.

[0019] Preferably, the arbuscular mycorrhizal fungus agent is at least one of Glomus mosseae, Glomus versiforme, Glomus intraradices, Glomus etunicatum.

[0020] Preferably, the preparation method of the selenium-containing complex microbial fertilizer containing arbuscular mycorrhizal fungus agent is as follows:

[0021] The selenium-rich straw is crushed, mixed and stirred with selenium-rich poultry manure, perlite, selenium-rich yeast, modified montmorillonite and humic acid, the water content is adjusted to 35-50%, arbuscular mycorrhizal fungus agent and bacillus subtilis are added for composting, the composting time is 25-30 days to obtain a crude product, and then the crude product is granulated and dried to obtain the selenium-containing complex microbial fertilizer containing arbuscular mycorrhizal fungus agent.

[0022] Further preferably, the composting temperature is 40-60 DEG C.

[0023] Further preferably, the number of bacteria in the selenium-containing complex microbial fertilizer containing arbuscular mycorrhizal fungus agent is 2.0-2.5 billion per gram.

[0024] The selenium-rich straw and the selenium-rich poultry manure can not only provide rich nutrients, but also improve the soil structure and promote the healthy development of the soil ecosystem, and contain nitrogen, phosphorus, potassium and other macroelements, and can also provide iron, zinc, manganese and other trace elements, and the nutrients are released slowly and last for a long time, and can provide nutrients and energy for soil microorganisms, and the selenium-rich straw, the selenium-rich poultry manure and the selenium-rich yeast form a multi-form selenium source system, utilize the symbiotic relationship of mycorrhiza and the synergistic effect of humic acid, significantly improve the bioavailability and conversion efficiency of selenium, significantly improve the selenium content of edible parts of crops, realize efficient selenium biofortification, increase soil microbial diversity, accelerate the decomposition and mineralization of organic matter, and enhance the stability of the soil ecosystem.

[0025] Compared with the prior art, the beneficial effects of the present application are:

[0026] 1) The selenium-containing complex microbial fertilizer containing arbuscular mycorrhizal fungus agent is obtained by granulating the selenium-rich straw, the selenium-rich poultry manure, sodium selenite, selenium-rich yeast, modified montmorillonite, humic acid and arbuscular mycorrhizal fungus agent after composting, the selenium-containing complex microbial fertilizer can effectively improve soil clodding, increase soil fertility, improve the water retention capacity of soil and increase the stress resistance of plants, promote the yield and quality of agricultural products, and is suitable for commercial market promotion.

[0027] 2) The application adds modified montmorillonite, which not only provides more habitat and colonization space for microbial strains, but also has enhanced chelation ability, optimized water retention performance and strong nutrient loading capacity, can promote the oxidation-reduction metabolism of the strains, secrete more substances that can promote the decomposition of selenium-rich straw and selenium-rich poultry manure, accelerate the composting temperature and organic matter degradation process, reduce the loss of nutrient elements, meet the nutrient demand of plant growth, at the same time, the loaded nutrient elements provide sufficient nutrient sources for microorganisms, promote the proliferation and activity maintenance of microorganisms, meet the diversified nutrient demand of crop growth period, thereby improving the growth performance of plants. DETAILED DESCRIPTION

[0028] For the sake of brevity, the articles used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0029] Part of the raw materials used in the application are as follows:

[0030] Montmorillonite, 325 mesh, purchased from Shijiazhuang Dezhe Mineral Products Co., Ltd.

[0031] Mortierella ramanniana, purchased from Beijing Academy of Agricultural and Forestry Sciences Institute of Plant Nutrition and Resources.

[0032] Bacillus subtilis, strain number CICC24717, purchased from China Industrial Microbial Strain Preservation and Management Center.

[0033] Selenium-rich straw is harvested in the households of farmers cooperating in Rongchang District, Chongqing, China, and rice straw rich in selenium elements is sprayed during planting. The selenium content in the selenium-rich straw is 0.123 mg / kg.

[0034] Selenium-rich poultry manure is excreted after poultry eat selenium-rich feed, and is harvested in the households of farmers cooperating in Rongchang District, Chongqing, China. The selenium content in the manure is 0.095 mg / kg.

[0035] Example 1

[0036] A preparation method of a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi agent, comprising the following steps:

[0037] After 400g of selenium-rich straw is crushed, it is mixed and stirred uniformly with 400g of selenium-rich poultry manure, 83g of perlite, 23.5g of selenium-rich yeast, 86g of modified montmorillonite, and 100g of humic acid, the water content is adjusted to 40%, 82g of arbuscular mycorrhizal fungi agent, 25g of Bacillus subtilis, and 42.6g of glucose are added for composting, the composting temperature is 40-60℃, the composting is turned over every 2-3 days, the composting time is 28 days to obtain a crude product, then the crude product is granulated and dried to obtain a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi agent.

[0038] The preparation method of the modified montmorillonite is as follows:

[0039] (1) 32.5 g of zinc chloride and 22.5 g of 2,5-dihydroxyterephthalic acid are added to 500 mL of N,N-dimethylformamide, mixed uniformly, then 85 g of montmorillonite is added, uniformly dispersed, and reacted with heating at 110°C for 8 h, 16 g of EDC and 15 g of NHS are further added and reacted for 2 h, after completion, cooled, filtered, and the solid is collected, washed and dried to obtain activated montmorillonite;

[0040] (2) 50 g of 2-amino-3-carboxy-1,4-naphthoquinone is dissolved in 500 mL of N,N-dimethylformamide, 80 g of activated montmorillonite is added, and the temperature is raised to 70°C for 6 h of reaction, after the reaction is completed, cooled, filtered, and the solid is collected, washed and dried to obtain a montmorillonite-naphthoquinone complex;

[0041] (3) 70 g of the montmorillonite-naphthoquinone complex is dispersed in 500 mL of dimethyl sulfoxide, 50 g of 2-hydroxypropyl-β-cyclodextrin and 3 g of p-toluenesulfonic acid are added, and the reaction is stirred at 110°C for 5 h, the solid is collected by filtration, washed and dried to obtain the modified montmorillonite.

[0042] Example 2

[0043] A preparation method of a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi, comprising the following steps:

[0044] After 300 g of selenium-rich straw is crushed, it is mixed with 300 g of selenium-rich poultry manure, 50 g of perlite, 10 g of selenium-rich yeast, 50 g of modified montmorillonite, and 50 g of humic acid, and stirred uniformly, the water content is adjusted to 35%, 50 g of arbuscular mycorrhizal fungi, 10 g of Bacillus subtilis, and 30 g of glucose are added for composting, the composting temperature is 40°C, the composting is turned over every 2-3 days, and the composting time is 25 days to obtain a crude product, then the crude product is granulated and dried to obtain a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi.

[0045] The preparation method of the modified montmorillonite is as follows:

[0046] (1) 32.5 g of zinc chloride and 22.5 g of 2,5-dihydroxyterephthalic acid are added to 500 mL of N,N-dimethylformamide, mixed uniformly, then 85 g of montmorillonite is added, uniformly dispersed, and reacted with heating at 110°C for 8 h, 16 g of EDC and 15 g of NHS are further added and reacted for 2 h, after completion, cooled, filtered, and the solid is collected, washed and dried to obtain activated montmorillonite;

[0047] (2) 60 g 2-amino-3-carboxy-1,4-naphthoquinone was dissolved in 500 mL of N,N-dimethylformamide, 100 g of the activated montmorillonite was added, and the temperature was raised to 80°C for 5 h of reaction. After the reaction was completed, it was cooled and filtered, and the solid was collected, washed and dried to obtain a montmorillonite-naphthoquinone complex;

[0048] (3) 100 g of the montmorillonite-naphthoquinone complex was dispersed in 500 mL of dimethyl sulfoxide, 60 g of 2-hydroxypropyl-β-cyclodextrin and 5 g of p-toluenesulfonic acid were added, and the mixture was stirred at 120°C for 4 h of reaction. The solid was collected by filtration, washed and dried to obtain the modified montmorillonite.

[0049] Example 3

[0050] A preparation method of a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi, comprising the following steps:

[0051] After 500 g of selenium-rich straw was crushed, it was mixed and stirred uniformly with 400 g of selenium-rich poultry manure, 100 g of perlite, 30 g of selenium-rich yeast, 100 g of modified montmorillonite, and 150 g of humic acid. The water content was adjusted to 50%, 100 g of arbuscular mycorrhizal fungi, 30 g of Bacillus subtilis, and 50 g of glucose were added for composting, the composting temperature was 60°C, the composting time was 30 days, and the composting was turned over every 2-3 days. The crude product was obtained, and then granulation and drying were performed to obtain a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi.

[0052] The preparation method of the modified montmorillonite is as follows:

[0053] (1) 40 g of zinc chloride and 30 g of 2,5-dihydroxyterephthalic acid were added to 500 mL of N,N-dimethylformamide and mixed uniformly. Then 100 g of montmorillonite was added, and after being uniformly dispersed, it was heated at 120°C for 6 h of reaction. Then 20 g of EDC and 20 g of NHS were added, and the reaction was continued for 2 h. After the reaction was completed, it was cooled, filtered, and the solid was collected, washed and dried to obtain the activated montmorillonite;

[0054] (2) 60 g of 2-amino-3-carboxy-1,4-naphthoquinone was dissolved in 500 mL of N,N-dimethylformamide, 100 g of the activated montmorillonite was added, and the temperature was raised to 80°C for 5 h of reaction. After the reaction was completed, it was cooled and filtered, and the solid was collected, washed and dried to obtain a montmorillonite-naphthoquinone complex;

[0055] (3) 100 g of the montmorillonite-naphthoquinone complex was dispersed in 500 mL of dimethyl sulfoxide, 60 g of 2-hydroxypropyl-β-cyclodextrin and 5 g of p-toluenesulfonic acid were added, and the mixture was stirred at 120°C for 4 h of reaction. The solid was collected by filtration, washed and dried to obtain the modified montmorillonite.

[0056] Comparative Example 1

[0057] A preparation method of a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi, comprising the following steps:

[0058] After 400g selenium-rich straw is crushed, it is mixed with 400g selenium-rich poultry manure, 83g perlite, 23.5g selenium-rich yeast, 86g modified montmorillonite, and 100g humic acid, and stirred uniformly, the water content is adjusted to 40%, 82g arbuscular mycorrhizal fungi, 25g bacillus subtilis, and 42.6g glucose are added for composting, the composting temperature is 40-60℃, the composting is turned over every 2-3 days, and the composting time is 28 days to obtain a crude product, then the crude product is granulated and dried to obtain the selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi.

[0059] The preparation method of the modified montmorillonite is as follows:

[0060] (1) 32.5g zinc chloride and 22.5g 2,5-dihydroxyterephthalic acid are added into 500mL N,N-dimethylformamide, mixed uniformly, then 85g montmorillonite is added, uniformly dispersed, heated to 110℃ and reacted for 8h, 16g EDC and 15g NHS are further added and reacted for 2h, after the reaction is completed, the solid is collected by cooling and filtering, washed and dried to obtain activated montmorillonite;

[0061] (2) 50g 2-amino-3-carboxy-1,4-naphthoquinone is dissolved in 500mL N,N-dimethylformamide, 80g activated montmorillonite is added, heated to 70℃ and reacted for 6h, after the reaction is completed, the solid is collected by cooling and filtering, washed and dried to obtain modified montmorillonite.

[0062] Comparative Example 2

[0063] A preparation method of a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi, comprising the following steps:

[0064] After 400g selenium-rich straw is crushed, it is mixed with 400g selenium-rich poultry manure, 83g perlite, 23.5g selenium-rich yeast, 86g modified montmorillonite, and 100g humic acid, and stirred uniformly, the water content is adjusted to 40%, 82g arbuscular mycorrhizal fungi, 25g bacillus subtilis, and 42.6g glucose are added for composting, the composting temperature is 40-60℃, the composting is turned over every 2-3 days, and the composting time is 28 days to obtain a crude product, then the crude product is granulated and dried to obtain the selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi.

[0065] The preparation method of the modified montmorillonite is as follows:

[0066] 32.5g of zinc chloride and 22.5g of 2,5-dihydroxyterephthalic acid were added into 500mL of N,N-dimethylformamide, mixed uniformly, then 85g of montmorillonite was added, uniformly dispersed, and reacted with heating at 110℃ for 8h, 16g of EDC and 15g of NHS were further added and reacted for 2h, after the reaction was completed, the mixture was cooled, filtered, and the solid was collected, washed and dried to obtain the modified montmorillonite.

[0067] Application Example

[0068] Nutrition test on the growth and development of vegetables: the selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi obtained in Examples 1-3 and Comparative Examples 1-2 was mixed with urea, potassium sulfate, superphosphate in a mass ratio of 1:1:1:3 to prepare 5 groups of compound fertilizers for standby; the experiment was divided into 5 groups, 10 pots per group, 2kg of soil was added to each pot during the potting experiment, and Shanghai green Chinese cabbage was planted, 3 plants per pot, and the above 5 groups of compound fertilizers were applied respectively, all the compound fertilizers were applied according to 50% base fertilizer and 50% topdressing, and were used on the first day and the fifteenth day of transplanting respectively, the planting period was 30d, and the other culture conditions were the same, the net weight increment of each plant was calculated after 30d of planting, each plant was tested 3 times, and the average value was taken as the test result, the test method of selenium content in the leaves of Chinese cabbage was that the leaves were dried after being picked, and then the selenium content was determined by atomic fluorescence spectrometry, and the test results are shown in Table 1:

[0069] Table 1 Nutrition test results on the growth and development of vegetables

[0070]

[0071] As can be seen from the experimental results in Table 1, the selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi obtained by the application has the characteristics of good fertility, can significantly improve the growth performance of vegetables, and the selenium content in the cultivated vegetables is high, the human body absorption rate of this biological selenium is high, and it has high nutritional function, compared with the production of selenium-rich vegetables by spraying inorganic selenium, the technology has the advantages of safety, easy absorption, good effect and small environmental pollution.

[0072] The above are only preferred embodiments of the application, and do not limit the patent scope of the application, and for those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the patent protection scope of the application.

Claims

1. A selenium-containing complex microbial fertilizer containing arbuscular mycorrhizal fungi, characterized in that: It comprises the following components by weight: 30-50 parts of selenium-rich straw, 35-50 parts of selenium-rich poultry manure, 5-10 parts of perlite, 1-3 parts of selenium-rich yeast, 5-10 parts of modified montmorillonite, 5-15 parts of humic acid, 5-10 parts of arbuscular mycorrhizal fungi agent, 1-3 parts of Bacillus subtilis, and 3-5 parts of glucose. The preparation method of the modified montmorillonite is as follows: (1) zinc chloride and 2,5-dihydroxyterephthalic acid are added to N,N-dimethylformamide, mixed uniformly, then montmorillonite is added, uniformly dispersed, heated for a period of time, and then EDC and NHS are added, and the reaction is continued to heat, to obtain activated montmorillonite; (2) 2-amino-3-carboxy-1,4-naphthoquinone is dissolved in N,N-dimethylformamide, and the activated montmorillonite is added, and the reaction is carried out at an elevated temperature to obtain a montmorillonite-naphthoquinone complex; (3) the montmorillonite-naphthoquinone complex is dispersed in dimethyl sulfoxide, 2-hydroxypropyl-β-cyclodextrin and p-toluenesulfonic acid are added, and the reaction is stirred to obtain modified montmorillonite; The mass ratio of zinc chloride, 2,5-dihydroxyterephthalic acid and montmorillonite in step (1) is 5-8:3-6:15-20; The heating reaction temperature in step (1) is 100-120℃, and the reaction time is 6-10h; The mass ratio of 2-amino-3-carboxy-1,4-naphthoquinone and activated montmorillonite in step (2) is 2-3:3-5; The reaction temperature in step (2) is 60-80℃, and the reaction time is 5-8h; The mass ratio of montmorillonite-naphthoquinone complex, 2-hydroxypropyl-β-cyclodextrin and p-toluenesulfonic acid in step (3) is 5-10:4-6:0.1-0.5; The arbuscular mycorrhizal fungi agent is at least one of Glomus mosseae, Glomus versiforme, Glomus geosporum, and Glomus intraradices.

2. A method of preparing the selenium-containing complex microbial fertilizer of claim 1, characterized in that, The method comprises the following steps: after the selenium-rich straw is crushed, it is mixed with selenium-rich poultry manure, perlite, selenium-rich yeast, modified montmorillonite, and humic acid, and stirred uniformly, the moisture content is adjusted to 35-50%, arbuscular mycorrhizal fungi agent, Bacillus subtilis, and glucose are added for composting, the compost is turned over every 2-3 days, the composting time is 25-30 days to obtain a crude product, and then the crude product is granulated and dried to obtain a selenium-containing composite microbial fertilizer containing arbuscular mycorrhizal fungi agent.

3. The method of claim 2, wherein: The composting temperature is 40-60℃.

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