A microbial composting inoculant for straw and its preparation method

Abstract

The present invention discloses a microbial composting agent for straw and its preparation method, belonging to the field of microbial technology. The microbial composting agent for straw of the present invention is prepared from the following raw materials in parts by weight: 15-18 parts of functional microbial liquid, 3-5 parts of neutral protease, 1-3 parts of laccase, 20-25 parts of nano-porous diatomite carrier, 5-7 parts of humectant, 2-3 parts of humic acid chelated trace elements, and 2-4 parts of inducer. The present invention screens Thermophilic Talaromyces, Thermoactinomyces guangxiensis, and Arthrobacter terregens to form a functional microbial liquid, adds a laccase-protease complex system in combination with the physical adsorption effect of diatomite, adds humic acid chelated trace elements to form an ion exchange network with polyglutamic acid, and efficiently degrades straw components, accelerates the composting process, and improves the quality of straw compost through the triple mechanisms of "enzymatic degradation - element supplementation - microenvironment regulation".

Description

Technical Field

[0001] The present invention belongs to the technical field of microbiology, and particularly relates to a microbial composting agent for straw and a preparation method thereof. Background Art

[0002] Straw is a by-product left idle after the harvest of agricultural products. China is a major grain-producing country, with a large variety and quantity of various straws. At present, most of the straws come from corn, rice and wheat, and the utilization of straw returning to the field is an issue we are concerned about. Crop straw contains nutrients such as nitrogen, phosphorus, potassium and trace elements, and is a sustainable biological resource. Straw returning to the field can increase the content of soil organic matter and is one of the important measures to promote the virtuous cycle of the agricultural ecosystem. However, in the natural state, the degradation rate of straw is relatively slow. However, adding a straw composting agent during the straw composting process can significantly increase the content of soluble organic carbon, microbial biomass carbon, particulate organic carbon, and high, medium and low active organic carbon in the soil under the no-tillage straw mulch returning to the field, subsoiling straw ploughing under the soil and rotary tillage straw ploughing under the soil modes. The straw composting agent is beneficial to the decomposition of difficult-to-decompose substances in straw and can accelerate the release of organic carbon, nitrogen and phosphorus in straw.

[0003] However, the chemical and physical structures of straw are complex, and it is extremely difficult to be degraded by microorganisms and enzymes into monomers; multiple enzymes with different specificities are required to degrade straw. Therefore, it is particularly important to prepare a composting microbial agent that can effectively accelerate straw composting and improve the quality of straw compost. Summary of the Invention

[0004] The purpose of the present invention is to provide a microbial composting agent for straw, which can efficiently degrade straw components, accelerate the composting process and improve the quality of straw compost through the triple mechanisms of "enzymatic degradation - element supplementation - microenvironment regulation".

[0005] In order to achieve the above technical purpose, the technical solution adopted by the present invention is as follows:

[0006] A microbial composting agent for straw, comprising the following raw materials in parts by weight: 15 - 18 parts of functional microbial liquid, 3 - 5 parts of neutral protease, 1 - 3 parts of laccase, 20 - 25 parts of nano-porous diatomite carrier, 5 - 7 parts of humectant, 2 - 3 parts of humic acid chelated trace elements, and 2 - 4 parts of inducer.

[0007] Further, the functional microbial liquid is Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter humicola; the Talaromyces thermophilus is purchased from the China General Microbiological Culture Collection Center, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, preservation date: February 19, 2016, preservation number: CGMCC No. 3.15538; the Thermoactinomyces guangxiensis is purchased from the China General Microbiological Culture Collection Center, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, preservation date: January 22, 2014, preservation number: CGMCC No. 4.7156; the Arthrobacter humicola is purchased from the China General Microbiological Culture Collection Center, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, preservation date: March 5, 2016, preservation number: CGMCC No. 1.15654.

[0008] Furthermore, the preparation method of the functional microbial liquid is as follows: Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter humicola are separately activated and enlarged cultured to obtain a bacterial liquid with a viable count of 1×10 9 CFU / ml, and then the three bacterial liquids are mixed according to a volume ratio of 1:1:1 to obtain the functional microbial liquid.

[0009] Further, the preparation method of the nano-porous diatomite carrier is as follows:

[0010] (1) Diatomite pretreatment: Soak the diatomite in 10% HCl solution, stir at 60°C for 2 h, then rinse with deionized water until neutral, dry, pass through a 200-mesh sieve, and calcine at 600°C for 2 h;

[0011] (2) Construction of nano-scale microporous structure: Grind the diatomite in step (1) with a ball mill to a particle size less than 100 nm, mix the diatomite, PEG, and deionized water in a ratio of 1 kg: 0.2 kg: 3 L to form a slurry, dry, and place it in a high-temperature furnace for calcination at 400°C for 2 h;

[0012] (3) Surface functionalization modification: Immerse the diatomite prepared in step (2) in 3% NaOH solution, perform ultrasonic treatment for 30 minutes, then mix 3% KH-550 solution with the diatomite, react at 60°C for 4 h, wash three times with absolute ethanol, and vacuum dry to constant weight to obtain the nano-porous diatomite carrier.

[0013] Furthermore, the 3% KH-550 solution in step (3) is prepared by dissolving KH-550 in ethanol; the 3% KH-550 solution and the diatomite are mixed according to a mass ratio of 2:1.

[0014] Further, the preparation method of the humic acid chelated trace element is as follows:

[0015] (1) Alkaline dissolution of humic acid: Mix humic acid powder and deionized water according to a mass ratio of 1:20, slowly dropwise add 1 mol / L NaOH solution, adjust the pH to 8, and stir until the humic acid is completely dissolved;

[0016] (2) Preparation of metal salt solution: Prepare 0.3 mol / L iron nitrate solution, zinc chloride solution, and sodium molybdate solution, and mix the three solutions to obtain a metal salt solution;

[0017] (3) Chelation reaction: Add the metal salt solution to the humic acid solution, adjust the pH to 7, react at 70 °C for 2 h, filter to remove unreacted particles, and spray-dry the solution to obtain humic acid chelated metal elements.

[0018] Furthermore, the volume ratio of the metal salt solution to the humic acid solution is 3:1.

[0019] Further, the moisturizer is polyglutamic acid; the inducer is trehalose and proline with a mass ratio of 1:1.

[0020] A preparation method of a microbial composting agent for straw is prepared by the following steps:

[0021] (1) Prepare nano-porous diatomite carrier, functional microbial liquid, and humic acid chelated trace element;

[0022] (2) Mix the nano-porous diatomite carrier, neutral protease, laccase, moisturizer, humic acid chelated trace element, and inducer evenly, and place them in a granulator for granulation to obtain solid carrier particles with a particle size of 3-5 mm;

[0023] (3) Prepare functional microbial liquid;

[0024] (4) Add the solid carrier particles prepared in step (2) to the functional microbial liquid prepared in step (3), perform sufficient adsorption, and then air-dry to obtain the final product of the agent.

[0025] When applying the agent of the present invention for straw fermentation, the addition amount is 1-3‰ of the mass of the straw raw material.

[0026] All raw materials of the present invention are commercially available.

[0027] The present invention selects three strains, namely *Talaromyces thermophilus*, *Thermoactinomyces guangxiensis*, and *Arthrobacter terregens*, to prepare a functional bacterial liquid for accelerating the decomposition of straw. Among them, *Talaromyces thermophilus* can secrete cellulase and xylanase to accelerate the decomposition of cellulose, hemicellulose, and lignin in straw, convert them into small-molecule organic substances that can be utilized by plants, and at the same time help the straw pile to heat up and maintain a high-temperature environment, accelerating the decomposition process of straw; *Thermoactinomyces guangxiensis* can secrete cellulase, hemicellulase, and lignin peroxidase to break the hard structure of straw, accelerate decomposition, and remain active during the high-temperature period of composting, can quickly increase the temperature of the pile body, continuously decompose refractory organic substances, shorten the straw decomposition cycle, and effectively kill pathogenic microorganisms and weed seeds during the high-temperature stage of composting, improving the safety of composting. *Arthrobacter terregens* can convert the straw decomposition products into precursors of humic acid, accelerate the synthesis of humus, regulate the micro-ecological environment, produce growth-promoting substances such as microorganisms and amino acids, stimulate the growth of other bacteria, form a synergistic effect, and at the same time has the ability to degrade organophosphorus pesticides, reducing the negative impact of pollutants in straw on the soil. The three bacteria have a synergistic effect after being mixed in equal proportions, which can achieve the efficient decomposition and rapid decomposition of straw, and at the same time promote the formation of humus and nutrient release. After the decomposed straw is returned to the soil, it increases the organic matter content and improves the soil ecology.

[0028] The present invention introduces a laccase-protease complex system, combined with the physical adsorption effect of diatomite, to significantly improve the lignin degradation efficiency. The humic acid chelated trace elements added in the present invention form an ion exchange network with polyglutamic acid, extending the effective period of the microbial agent to 120 days.

[0029] Beneficial effects

[0030] The present invention realizes a "mesophilic bacteria-thermophilic bacteria" gradient activation system, and through the nano-carrier slow-release technology, continuous degradation at normal temperature and high temperature of 40-60 °C is achieved. The microbial decomposition agent of the present invention can efficiently decompose straw components, accelerate the decomposition process, and improve the quality of compost through the triple mechanisms of "enzymatic degradation-element supplementation-microenvironment regulation". The microbial decomposition agent of the present invention is suitable for the fermentation of straw such as corn and wheat, with a small addition amount and high composting efficiency. Specific implementation manners

[0031] The technical solutions of the present invention will be further described below in conjunction with specific embodiments, but not limited thereto.

[0032] Example 1

[0033] A microbial decomposition agent for straw comprises the following raw materials in parts by weight: 15 parts of functional microbial bacterial liquid, 3 parts of neutral protease, 1 part of laccase, 20 parts of nano-porous diatomite carrier, 5 parts of moisturizer, 2 parts of humic acid chelated trace elements, and 2 parts of inducer.

[0034] The functional microbial liquid is Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter humicola; the strain number of Talaromyces thermophilus is CGMCC No. 3.15538; the strain number of Thermoactinomyces guangxiensis is CGMCC No. 4.7156; the strain number of Arthrobacter humicola is CGMCC No. 1.15654.

[0035] The preparation method of the functional microbial liquid is as follows: Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter humicola are separately activated and enlarged cultured to obtain a bacterial liquid with a viable count of 1×10 9 CFU / ml, and then the three bacterial liquids are mixed according to a volume ratio of 1:1:1 to obtain the functional microbial liquid.

[0036] The preparation method of the nano-porous diatomite carrier is as follows:

[0037] (1) Diatomite pretreatment: The diatomite is soaked in 10% HCl solution, stirred at 60°C for 2 h, rinsed with deionized water until neutral, dried, sieved through a 200-mesh sieve, and calcined at 600°C for 2 h;

[0038] (2) Construction of nano-scale microporous structure: The diatomite in step (1) is ground by a ball mill to a particle size less than 100 nm, and the diatomite, PEG, and deionized water are mixed according to a ratio of 1 kg: 0.2 kg: 3 L to form a slurry, which is dried and then calcined in a high-temperature furnace at 400°C for 2 h;

[0039] (3) Surface functionalization modification: The diatomite prepared in step (2) is immersed in 3% NaOH solution, ultrasonically treated for 30 minutes, then 3% KH-550 solution is mixed with the diatomite, reacted at 60°C for 4 h, washed three times with absolute ethanol, and vacuum dried to constant weight to obtain the nano-porous diatomite carrier.

[0040] The 3% KH-550 solution in step (3) is prepared by dissolving KH-550 in ethanol; the 3% KH-550 solution and the diatomite are mixed according to a mass ratio of 2:1.

[0041] The preparation method of the humic acid chelated trace elements is as follows:

[0042] (1) Alkaline dissolution of humic acid: The humic acid powder and deionized water are mixed according to a mass ratio of 1:20, 1 mol / L NaOH solution is slowly added dropwise, the pH is adjusted to 8, and stirred until the humic acid is completely dissolved;

[0043] (2) Preparation of metal salt solution: Prepare 0.3 mol / L iron nitrate solution, zinc chloride solution, and sodium molybdate solution, and mix the three solutions to obtain a metal salt solution;

[0044] (3) Chelation reaction: Add the metal salt solution to the humic acid solution, adjust the pH to 7, react at 70 °C for 2 h, filter to remove unreacted particles, and spray-dry the solution to obtain humic acid chelated metal elements.

[0045] The volume ratio of the metal salt solution to the humic acid solution is 3:1.

[0046] The moisturizer is polyglutamic acid; the inducer is trehalose and proline with a mass ratio of 1:1.

[0047] A preparation method of a microbial composting agent for straw is prepared by the following steps:

[0048] (1) Prepare a nano-porous diatomite carrier, a functional microbial liquid, and humic acid chelated trace elements;

[0049] (2) Mix the nano-porous diatomite carrier, neutral protease, laccase, moisturizer, humic acid chelated trace elements, and inducer evenly, and place them in a granulator for granulation to obtain solid carrier particles with a particle size of 3-5 mm;

[0050] (3) Prepare a functional microbial liquid;

[0051] (4) Add the solid carrier particles prepared in step (2) to the functional microbial liquid prepared in step (3), perform sufficient adsorption, and then air-dry to obtain the final product microbial agent.

[0052] Example 2

[0053] A microbial composting agent for straw includes the following raw materials in parts by weight: 16 parts of functional microbial liquid, 4 parts of neutral protease, 2 parts of laccase, 23 parts of nano-porous diatomite carrier, 6 parts of moisturizer, 3 parts of humic acid chelated trace elements, and 3 parts of inducer.

[0054] The functional microbial liquid is Thermophilic Talaromyces, Thermoactinomyces guangxiensis, and Arthrobacter humicola; the strain number of Thermophilic Talaromyces (Talaromyces thermophilus) is CGMCC No. 3.15538; the strain number of Thermoactinomyces guangxiensis is CGMCC No. 4.7156; the strain number of Arthrobacter humicola is CGMCC No. 1.15654.

[0055] The preparation method of the functional microbial bacterial liquid is as follows: Thermoascus aurantiacus, Thermoactinomyces guangxiensis, and Arthrobacter terregens are separately activated and amplified cultured to obtain bacterial liquids with viable cell counts of 1×10 9 CFU / ml, and then the three bacterial liquids are mixed according to a volume ratio of 1:1:1 to obtain the functional microbial bacterial liquid.

[0056] The preparation method of the nano-porous diatomite carrier is as follows:

[0057] (1) Diatomite pretreatment: Soak diatomite in 10% HCl solution, stir at 60°C for 2 h, wash with deionized water until neutral, dry, pass through a 200-mesh sieve, and calcine at 600°C for 2 h;

[0058] (2) Construction of nano-scale microporous structure: Grind the diatomite in step (1) with a ball mill to a particle size less than 100 nm, mix diatomite, PEG, and deionized water in a ratio of 1 kg: 0.2 kg: 3 L to form a slurry, dry, and calcine in a high-temperature furnace at 400°C for 2 h;

[0059] (3) Surface functional modification: Immerse the diatomite prepared in step (2) in 3% NaOH solution, perform ultrasonic treatment for 30 minutes, then mix 3% KH-550 solution with diatomite, react at 60°C for 4 h, wash three times with absolute ethanol, and vacuum dry to constant weight to obtain the nano-porous diatomite carrier.

[0060] In step (3), the 3% KH-550 solution is prepared by dissolving KH-550 in ethanol; the 3% KH-550 solution and diatomite are mixed according to a mass ratio of 2:1.

[0061] The preparation method of the humic acid chelated trace elements is as follows:

[0062] (1) Alkaline dissolution of humic acid: Mix humic acid powder and deionized water according to a mass ratio of 1:20, slowly add 1 mol / L NaOH solution, adjust the pH to 8, and stir until the humic acid is completely dissolved;

[0063] (2) Preparation of metal salt solution: Prepare 0.3 mol / L iron nitrate solution, zinc chloride solution, and sodium molybdate solution, and mix the three solutions to obtain the metal salt solution;

[0064] (3) Chelation reaction: Add the metal salt solution to the humic acid solution, adjust the pH to 7, react at 70°C for 2 h, filter to remove unreacted particles, and spray-dry the solution to obtain the humic acid chelated metal elements.

[0065] The volume ratio of the metal salt solution to the humic acid solution is 3:1.

[0066] The humectant is polyglutamic acid; the inducer is trehalose and proline with a mass ratio of 1:1.

[0067] A preparation method of a microbial composting agent for straw is prepared by the following steps:

[0068] (1) Prepare a nano-porous diatomite carrier, a functional microbial liquid, and a humic acid chelated trace element;

[0069] (2) Mix the nano-porous diatomite carrier, neutral protease, laccase, humectant, humic acid chelated trace element, and inducer evenly, and place them in a granulator for granulation to obtain solid carrier particles with a particle size of 3-5 mm;

[0070] (3) Prepare a functional microbial liquid;

[0071] (4) Add the solid carrier particles prepared in step (2) to the functional microbial liquid prepared in step (3), perform sufficient adsorption, and then air-dry to obtain the final product microbial agent.

[0072] Example 3

[0073] A microbial composting agent for straw, comprising the following raw materials in parts by weight: 18 parts of functional microbial liquid, 5 parts of neutral protease, 3 parts of laccase, 25 parts of nano-porous diatomite carrier, 7 parts of humectant, 3 parts of humic acid chelated trace element, and 4 parts of inducer.

[0074] The functional microbial liquid is Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter humicola; the strain number of Talaromyces thermophilus is CGMCC No. 3.15538; the strain number of Thermoactinomyces guangxiensis is CGMCC No. 4.7156; the strain number of Arthrobacter humicola is CGMCC No. 1.15654.

[0075] The preparation method of the functional microbial liquid is: separately activate and expand the cultivation of Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter humicola to obtain a bacterial liquid with a viable count of 1×10 9 CFU / ml, and then mix the three bacterial liquids in a volume ratio of 1:1:1 to obtain a functional microbial liquid.

[0076] The preparation method of the nano-porous diatomite carrier is:

[0077] (1) Diatomite pretreatment: Immerse diatomite in a 10% HCl solution, stir at 60°C for 2 h, then rinse with deionized water until neutral, dry, pass through a 200-mesh sieve, and calcine at 600°C for 2 h;

[0078] (2)Construction of nanoscale microporous structure: Grind the diatomite in step (1) with a ball mill to a particle size less than 100 nm. Mix diatomite, PEG, and deionized water in a ratio of 1 kg: 0.2 kg: 3 L to form a slurry. After drying, place it in a high-temperature furnace and calcine at 400 °C for 2 h;

[0079] (3)Surface functionalization modification: Immerse the diatomite prepared in step (2) in a 3% NaOH solution and ultrasonically treat it for 30 minutes. Then mix the 3% KH-550 solution with the diatomite and react at 60 °C for 4 h. Wash it three times with absolute ethanol and vacuum dry it to a constant weight to obtain a nano-porous diatomite carrier.

[0080] The 3% KH-550 solution in step (3) is prepared by dissolving KH-550 in ethanol; the 3% KH-550 solution and diatomite are mixed in a mass ratio of 2:1.

[0081] The preparation method of the humic acid chelated trace elements is as follows:

[0082] (1)Alkaline dissolution of humic acid: Mix humic acid powder and deionized water in a mass ratio of 1:20, slowly add a 1 mol / L NaOH solution, adjust the pH to 8, and stir until the humic acid is completely dissolved;

[0083] (2)Preparation of metal salt solution: Prepare a 0.3 mol / L iron nitrate solution, zinc chloride solution, and sodium molybdate solution, and mix the three solutions to obtain a metal salt solution;

[0084] (3)Chelation reaction: Add the metal salt solution to the humic acid solution, adjust the pH to 7, react at 70 °C for 2 h, filter to remove unreacted particles, and spray-dry the solution to obtain humic acid chelated metal elements.

[0085] The volume ratio of the metal salt solution to the humic acid solution is 3:1.

[0086] The moisturizer is polyglutamic acid; the inducer is trehalose and proline with a mass ratio of 1:1.

[0087] A preparation method of a microbial composting agent for straw is prepared by the following steps:

[0088] (1)Prepare a nano-porous diatomite carrier, a functional microbial liquid, and humic acid chelated trace elements;

[0089] (2)Mix the nano-porous diatomite carrier, neutral protease, laccase, moisturizer, humic acid chelated trace elements, and inducer evenly, and place them in a granulator for granulation to obtain solid carrier particles with a particle size of 3 - 5 mm;

[0090] (3)Prepare a functional microbial liquid;

[0091] (4) Add the solid carrier particles prepared in step (2) to the functional microbial inoculum prepared in step (3), perform sufficient adsorption, and then air-dry to obtain the final product microbial inoculant.

[0092] Comparative Example

[0093] In each comparative example, change the volume ratio of the inoculum of Thermoascus aurantiacus, Thermoactinomyces guangxiensis, and Arthrobacter turicensis in the preparation of the functional microbial inoculum. The other raw materials and steps are the same as in Example 3. The specific inoculum composition is shown in Table 1.

[0094] Table 1 Inoculum Composition of Each Comparative Example

[0095]

[0096] Performance Test

[0097] The test straw is corn straw.

[0098] A total of 12 treatment groups were set up in the test: adding the microbial composting agents prepared in Examples 1-3 and Comparative Examples 1-9.

[0099] Collect, dry in the sun, pick, and then crush the corn straw into small sections of 3-5 cm, adjust the moisture content to about 60%, and when squeezing the material by hand, there is water between the fingers but it does not flow out. Add the corresponding microbial composting inoculant to each treatment group, and evenly sprinkle it at a dosage of 1‰ of the straw quality. After mixing evenly, stack it into a long strip pile with a length × width × height = 2 m × 1 m × 1.5 m. Turn the pile on the 1st, 3rd, 7th, 10th, 17th, 30th, 45th, and 60th days respectively.

[0100] Test methods for each index:

[0101] (1) Temperature of the pile body

[0102] Measure the temperature of the compost material every day initially, and measure it every 3 days after 17 days. Take 3 replicates each time.

[0103] (2) Determination of total nitrogen, total potassium, and total phosphorus

[0104] At the end of composting, collect samples by the 5-point mixing sampling method, and collect about 0.5 kg at each point. Total nitrogen is determined by a SKALAR segmented flow analyzer; total phosphorus is determined by the molybdenum antimony anti-colorimetric method; total potassium is determined by a flame spectrophotometer; take 3 replicates each time during measurement.

[0105] (3) Determination of C / N

[0106] At the end of the composting process, samples were collected using the 5-point mixed sampling method. The air-dried samples were crushed using a pulverizer, and 20 mg of the sample was weighed out after passing through a 100-mesh sieve and placed in tin foil. The total nitrogen and total carbon contents were detected using an elemental analyzer, and the C / N was calculated. Each treatment group was measured three times repetitively.

[0107] (4)Straw weight loss rate

[0108] The corn straw was crushed into small sections of 3 - 5 cm, and 1000 g was weighed and placed in a nylon bag. It was dried at 85 °C for 4 h, and the initial weight W0 was accurately measured. Then, the microbial composting agent of each treatment group was added to the nylon bag, with the addition amount of the composting agent being 1 g, and the water holding capacity was controlled at about 60%. Three replicates were set for each treatment group. After the straw was completely composted, it was rinsed with tap water until the dripping water was colorless, and then the sample was dried at 85 °C for 12 h, and the weight W1 of each bag of straw was recorded.

[0109] Straw weight loss rate (%) = (W0 - W1) / W0 × 100%; W0 is the weight of the original straw (g), and W1 is the dry weight of the straw after decomposition (g).

[0110] Table 2 Test results of straw composting experiment

[0111]

[0112] As can be seen from the data in Tables 1 and 2, the microbial composting agent of the present invention has a high composting efficiency and good degradation effect. Specifically, the highest temperature can reach 67 °C about 7 days after adding the microbial composting agent of the present invention, and the highest temperature can reach 67 °C, and the duration when the temperature reaches above 50 °C is significantly extended; in addition, the weight loss rate of the straw can reach 65% after adding the composting agent, and it also has high organic matter, total nitrogen, total potassium, and total phosphorus contents. For the control groups 1 - 9 with the changed composition of the microbial agent, the synergistic balance of the three bacteria, Thermophilic Talaromyces, Thermoactinomyces guangxiensis, and Arthrobacter humicola, is broken, resulting in a different degree of decline in the straw composting effect. Therefore, the three selected functional strains in the microbial composting agent of the present invention are all indispensable.

[0113] It should be noted that the above-mentioned embodiments are only some of the preferred embodiments for implementing the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

Claims

1. A microbial composting agent for straw, characterized in that, The invention comprises the following raw materials in parts by weight: 15-18 parts of functional microbial liquid, 3-5 parts of neutral protease, 1-3 parts of laccase, 20-25 parts of nanoporous diatomaceous earth carrier, 5-7 parts of moisturizer, 2-3 parts of humic acid chelated trace elements, and 2-4 parts of inducer; The functional microbial liquid is Talaromyces thermophilus, Thermoactinomyces guangxiensis, and Arthrobacter turicensis; the strain number of Talaromyces thermophilus ( Talaromyces thermophilus ) is CGMCC No. 3.15538; the strain number of Thermoactinomyces guangxiensis ( Thermoactinomyces guangxiensis ) is CGMCC No. 4.7156; the strain number of Arthrobacter turicensis ( Arthrobacter humicola ) is CGMCC No. 1.15654; The preparation method of the functional microbial liquid is as follows: Thermoascus aurantiacus, Thermoactinomyces guangxiensis, and Arthrobacter terregens are separately activated and enlarged in culture to obtain bacterial liquids with viable cell counts of 1×10 9 CFU / ml, and then the three bacterial liquids are mixed according to a volume ratio of 1:1:1 to obtain the functional microbial liquid.

2. The microbial composting inoculant for straw according to claim 1, wherein, The preparation method of the nanoporous diatomaceous earth carrier is: (1) Diatomite pretreatment: diatomite was soaked in 10% HCl solution, stirred at 60°C for 2 h, rinsed with deionized water until neutral, dried, sieved with 200 mesh, and calcined at 600°C for 2 h; (2) Construction of nanoscale microporous structure: Grind the diatomaceous earth in step (1) with a ball mill until the particle size is less than 100 nm, mix the diatomaceous earth, PEG, and deionized water in a ratio of 1 kg: 0.2 kg: 3 L to form a slurry, dry it, and calcine it in a high-temperature furnace at 400 °C for 2 h; (3) Surface functionalization modification: The diatomaceous earth prepared in step (2) was immersed in a 3% NaOH solution and subjected to ultrasonic treatment for 30 minutes. Then, a 3% KH-550 solution was mixed with the diatomaceous earth and reacted at 60° C. for 4 hours. The diatomaceous earth was then washed three times with anhydrous ethanol and vacuum dried to constant weight to obtain a nanoporous diatomaceous earth carrier.

3. The microbial composting inoculant for straw according to claim 2, characterized in that, The 3% KH-550 solution in step (3) is prepared by dissolving KH-550 in ethanol; the 3% KH-550 solution and diatomaceous earth are mixed in a mass ratio of 2:

1.

4. The microbial composting inoculant for straw according to claim 1, characterized in that, The preparation method of the humic acid chelated trace elements is: (1) Humic acid alkaline solution: Mix humic acid powder and deionized water in a mass ratio of 1:20, slowly add 1 mol / L NaOH solution, adjust the pH to 8, and stir until the humic acid is completely dissolved; (2) Preparation of metal salt solution: prepare 0.3 mol / L ferric nitrate solution, zinc chloride solution and sodium molybdate solution, and mix the three solutions to obtain a metal salt solution; (3) Chelating reaction: Add the metal salt solution to the humic acid solution, adjust the pH to 7, react at 70°C for 2 h, filter to remove unreacted particles, and spray dry the solution to obtain humic acid chelated metal elements.

5. The microbial composting inoculant for straw according to claim 4, wherein, The volume ratio of the metal salt solution to the humic acid solution is 3:

1.

6. The microbial composting inoculant for straw according to claim 1, wherein, The moisturizing agent is polyglutamic acid; the inducing agent is trehalose and proline in a mass ratio of 1:

1.

7. A preparation method of the microbial composting inoculant for straw according to any one of claims 1-6, characterized in that, Prepared by the following steps: (1) Preparation of nanoporous diatomaceous earth carrier, functional microbial culture liquid, and humic acid chelated trace elements; (2) mixing the nanoporous diatomaceous earth carrier, neutral protease, laccase, moisturizer, humic acid chelated trace elements, and inducer uniformly, placing the mixture in a granulator for granulation, and obtaining solid carrier particles with a particle size of 3-5 mm; (3) Preparation of functional microbial culture liquid; (4) The solid carrier particles prepared in step (2) are added to the functional microbial solution prepared in step (3) for sufficient adsorption, followed by air drying to obtain the final product, a microbial decomposition agent.

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