Livestock and poultry manure-based mixed organic fertilizer and production process thereof

Abstract

The invention relates to the technical field of organic fertilizer production, in particular to a mixed organic fertilizer based on livestock and poultry manure and a production process thereof, and the mixed organic fertilizer comprises the following raw materials: livestock and poultry manure, straw powder, plant ash, modified humic acid, a complex microbial inoculant, a modified water-retaining agent, a trace element additive and a binder. According to the invention, the modified humic acid is subjected to activation and integration treatment, so that the capability of exciting soil activity and stabilizing nutrients of the modified humic acid is remarkably improved; the complex microbial inoculant adopts a microcapsule embedding technology, so that the activity of functional microorganisms is effectively protected, and the functional microorganisms can stably survive and continuously play a role in a fertilizer environment; the modified water-retaining agent forms a three-dimensional network structure through graft copolymerization, and has excellent water absorption and retention performance and nutrient slow release function.

Description

Technical Field

[0001] This invention relates to the field of organic fertilizer production technology, specifically to a mixed organic fertilizer based on livestock and poultry manure and its production process. Background Technology

[0002] Mixed organic fertilizer made from livestock and poultry manure is a compound organic fertilizer made from livestock and poultry manure such as pig manure, chicken manure, and cow manure as the main raw materials, combined with auxiliary materials such as straw, sawdust, and mushroom residue. It is made through composting and fermentation and harmless treatment (killing pathogens and insect eggs). The nutrients are released slowly and comprehensively, which can meet the nutritional needs of crops throughout their entire growth period, avoid nutrient loss caused by excessive chemical fertilizers, and reduce the risk of soil salinization.

[0003] In existing technologies, functional microbial agents are largely inactivated due to inhibition by alkaline components in the fertilizer system (such as wood ash) and abiotic stress during the production process, making it difficult for them to exert their biofertilizer effects. Conventional water-retaining agents have poor compatibility with the alkaline environment of fertilizers and have limited functions, making it impossible to achieve synergistic water and fertilizer effects. More importantly, the raw material components are mostly simple physical mixtures, resulting in inherent antagonistic effects.

[0004] Based on this, the present invention provides a mixed organic fertilizer based on livestock and poultry manure and its production process. Summary of the Invention

[0005] The purpose of this invention is to provide a mixed organic fertilizer based on livestock and poultry manure and its production process. The mixed organic fertilizer prepared by this invention not only contains high levels of organic matter and humic acid, but also has a high survival rate of microbial agents.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a mixed organic fertilizer based on livestock and poultry manure and its production process, comprising the following raw materials in parts by weight: 60-70 parts livestock and poultry manure, 20-30 parts straw powder, 5-8 parts wood ash, 10-20 parts modified humic acid, 5-10 parts compound microbial agent, 3-7 parts modified water-retaining agent, 3-5 parts trace element additives, and 3-5 parts binder; The modified humic acid is obtained by activating and chelating weathered coal with citric acid and neutralizing and modifying it with wood ash. The compound microbial agent is composed of Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis compounded and encapsulated. The modified water-retaining agent is obtained by modifying starch-humic acid-grafted acrylic acid copolymer with wood ash.

[0007] Preferably, the preparation steps of the modified humic acid are as follows: select weathered coal as humic acid raw material, crush and sieve it, mix humic acid powder with citric acid solution and add it to a reaction vessel, stir and react for 2-3 hours at 70-80℃ and 150-200rpm; after the reaction is completed, add wood ash to the system and adjust the pH value of the system to 7.0-7.5, spray dry the neutralized slurry or transfer it to a drying oven and dry it at 80-90℃, after drying, crush the block and pass it through a 100-120 mesh sieve to obtain the sieve-less material, thus obtaining modified humic acid.

[0008] Preferably, the citric acid solution has a mass fraction of 5-8%, and the solid-liquid ratio of humic acid powder to citric acid is 1:(8-10).

[0009] Preferably, the preparation steps of the compound microbial agent are as follows: Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis are compounded and inoculated into a fermentation medium, and fermented at 30-37℃ and 150-200rpm for 24-48h; the fermentation broth is centrifuged and the bacterial cells are collected, and then resuspended in sterile physiological saline to obtain a concentrated bacterial cell solution; the concentrated bacterial cell solution is mixed with an embedding solution and stirred thoroughly to obtain a mixed solution; the mixed solution is dripped into a calcium chloride solution using a dripping device, and the droplets form gel microspheres upon contact with the calcium chloride solution, and are allowed to stand and solidify for 20-30min; the solidified gel microspheres are collected and dehydrated by freeze drying or low-temperature fluidized bed drying to obtain the compound microbial agent.

[0010] Preferably, the Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis are compounded at a live cell ratio of 1:1:1; the embedding solution is a sodium alginate solution, and the bacterial concentrate is mixed with the embedding solution at a volume ratio of 1:(3-5); the mass fraction of the calcium chloride solution is 1.5-2.5%.

[0011] Preferably, the fermentation medium contains 10-20 g / L glucose, 5-10 g / L peptone, 2-5 g / L yeast extract, and 1-2 g / L potassium dihydrogen phosphate; the embedding solution is prepared by dissolving sodium alginate in deionized water to form a sodium alginate solution with a mass fraction of 2.0-3.0%, which is then sterilized at 121°C for 20 min and cooled to room temperature.

[0012] Preferably, the preparation steps of the modified water-retaining agent are as follows: corn starch is added to deionized water and mixed, and stirred and gelatinized at 90-95℃ for 30-40 minutes to obtain a starch paste, which is then cooled to 50-55℃; the modified humic acid product is directly added to the starch paste, and the mixture is vigorously stirred and ultrasonically assisted to ensure uniform dispersion, thus obtaining a starch-humic acid mixed base material; acrylic acid is slowly added to the mixed base material while maintaining the temperature at 50-55℃, and then slowly mixed with a 5% (w / w) wood ash extract. Adjust the pH of the system to 6.0-6.5, add the initiator potassium persulfate and the crosslinking agent N,N'-methylenebisacrylamide, and purge with nitrogen for protection. React at 55-60℃ for 3-4 hours to obtain a graft copolymer gel. Crush the obtained gel, mix it evenly with wood ash, and stir at 60-65℃ for 1-1.5 hours. After treatment, dry it at 80-85℃ to constant weight, then pulverize it and pass it through an 80-100 mesh sieve to obtain the sieve-through material, thus obtaining the modified water-retaining agent.

[0013] Preferably, the amount of corn starch added is 10-15 parts, deionized water is 50-70 parts, modified humic acid product is 5-8 parts, acrylic acid is 20-25 parts, and wood ash is 1-2 parts; the amount of potassium persulfate initiator added is 0.8-1.2% of acrylic acid, and the amount of N,N'-methylenebisacrylamide crosslinking agent added is 0.3-0.5% of acrylic acid.

[0014] Preferably, the binder is bentonite, and the trace element additive is one of zinc sulfate, ferrous sulfate, and borax.

[0015] A production process for mixed organic fertilizer based on livestock and poultry manure includes the following steps: S1: Aerobic fermentation: The livestock and poultry manure is aerobically fermented, with the temperature controlled at 50-65℃. The pile is turned over once every 24 hours and fermented for 7-15 days until the moisture content is less than 30%, thus obtaining fermented manure. S2: Premix preparation: Add straw powder, wood ash, modified humic acid, modified water-retaining agent, trace element additives and binder into a mixer in proportion, and mix at a stirring speed of 200-300 rpm for 10-20 minutes to obtain the premix. S3: Main mixing: Mix the fermented manure obtained in S1 with the premix obtained in S2, mix at a stirring speed of 150-200 rpm for 15-30 minutes, and adjust the moisture content of the mixture to 30-40%; S4: Granulation: The mixture obtained in S3 is fed into a granulator for granulation, and the granulation particle size is controlled to be 2-4mm. S5: Drying and application of microbial agent: Dry the granules at 50-60℃ for 1-2 hours until the moisture content is less than 15%; then, after the granules have cooled to room temperature, apply the composite microbial agent evenly to the surface of the granules by spraying. S6: After drying and inoculating with microbial agents, the granules are sieved, and qualified granules with a particle size of 2-4mm are packaged to obtain mixed organic fertilizer.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention utilizes humic acid obtained by activating and neutralizing wood ash with citric acid. Its active functional groups are fully activated, which not only enhances its ability to improve soil and stimulate crop growth, but also efficiently integrates metal ions in trace element additives to form a stable organic-inorganic complex. This effectively prevents nutrients from being fixed by the soil and significantly improves the bioavailability of trace elements in fertilizers.

[0017] 2. The present invention provides a composite microbial agent prepared by microencapsulation technology. The microbial community inside is protected and can effectively resist the alkaline environment created by wood ash in the fertilizer system and the high temperature stress of the drying process, ensuring that highly active microorganisms can enter the soil. These microorganisms work synergistically with modified humic acid, livestock and poultry manure and other organic matrices to accelerate the humification and mineralization process of organic matter and continuously release nutrients.

[0018] 3. The present invention provides a water-retaining agent obtained by graft copolymerization and introduction of humic acid into a polymer network, followed by modification with wood ash. This agent has both excellent water absorption and swelling properties and slow-release nutrient function. It can not only provide moisture to crops and microbial agents for a long time, but its three-dimensional network structure can also adsorb and load nutrients integrated by modified humic acid, realizing the simultaneous slow release of water and fertilizer. In synergy with microbial agents and humic acid, it creates a benign micro-ecological environment that retains water and fertilizer and promotes growth. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application are described clearly and completely.

[0021] Example 1: A mixed organic fertilizer based on livestock and poultry manure and its production process, comprising the following raw materials in parts by weight: 60 parts livestock and poultry manure, 20 parts straw powder, 5 parts wood ash, 10 parts modified humic acid, 5 parts alkali-resistant modified compound microbial agent, 3 parts modified water-retaining agent, 3 parts trace element additives, and 3 parts binder. Modified humic acid is obtained by activating and chelating weathered coal with citric acid and neutralizing it with wood ash. The compound microbial agent is composed of Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis compounded and encapsulated. The modified water-retaining agent is obtained by modifying starch-humic acid-grafted acrylic acid copolymer with wood ash.

[0022] The preparation steps of modified humic acid are as follows: Weathered coal is selected as the raw material for humic acid. The weathered coal is crushed using a crusher and passed through a 120-mesh sieve. The sieved powder is placed in a drying oven and dried at 60℃ until the moisture content is ≤8%, obtaining dried humic acid powder. The humic acid powder is mixed with citric acid solution and added to a reaction vessel. Stirring is started, the speed is controlled at 150 rpm, and the temperature is raised to 70℃. The reaction is maintained at this temperature for 2 hours. After the reaction is completed, wood ash is slowly added to the system under continuous stirring to adjust the pH value of the system to 7.0. The neutralized slurry is spray-dried (inlet air temperature 180℃, outlet air temperature 80℃) or transferred to a drying oven and dried at 80℃. The dried lumps are crushed and passed through a 100-mesh sieve to obtain the sieve-through material, thus obtaining modified humic acid.

[0023] The citric acid solution has a mass fraction of 5%, and the solid-liquid ratio of humic acid powder to citric acid is 1:8.

[0024] The preparation steps of the compound microbial agent are as follows: Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis are mixed and inoculated into a fermentation medium, and fermented at 30℃ and 150 rpm for 24 h; the fermentation broth is centrifuged and the bacterial cells are collected, then resuspended in sterile physiological saline and concentrated to a bacterial concentration ≥5×10⁻⁶. 10 CFU / mL was used to obtain a concentrated bacterial cell solution. The concentrated bacterial cell solution was mixed with the embedding solution and stirred thoroughly to obtain a mixed solution. The mixed solution was dropped into a calcium chloride solution using a dropper. The droplets formed gel microspheres upon contact with the calcium chloride solution and were allowed to stand for 20 minutes to solidify. The solidified gel microspheres were collected and washed twice with sterile deionized water to remove residual calcium chloride on the surface. Then, they were dehydrated by freeze drying or low-temperature fluidized bed drying (temperature ≤40℃) to obtain the composite bacterial agent.

[0025] Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis were compounded at a live cell ratio of 1:1:1; the embedding solution was sodium alginate solution, and the bacterial concentrate was mixed with the embedding solution at a volume ratio of 1:3; the mass fraction of calcium chloride solution was 1.5%.

[0026] The fermentation medium contained 10 g / L glucose, 5 g / L peptone, 2 g / L yeast extract, and 1 g / L potassium dihydrogen phosphate. The embedding solution was prepared by dissolving sodium alginate in deionized water to form a 2.0% sodium alginate solution, which was then sterilized at 121°C for 20 min and cooled to room temperature.

[0027] The preparation steps of the modified water-retaining agent are as follows: Corn starch is mixed with deionized water and stirred at 90℃ for 30 min to obtain starch paste, which is then cooled to 50℃; the modified humic acid product is directly added to the starch paste, and the mixture is stirred vigorously (300 rpm) and ultrasonically assisted (300 W power, 20 min) to ensure uniform dispersion, thus obtaining a starch-humic acid mixed base material; acrylic acid is slowly added to the mixed base material while maintaining the temperature at 50℃, and the pH of the system is slowly adjusted to 6.0 with 5% wood ash extract by mass fraction; potassium persulfate initiator and N,N'-methylenebisacrylamide crosslinking agent are added, and nitrogen gas is introduced for protection. The mixture is reacted at 55℃ for 3 h to obtain a graft copolymer gel; the obtained gel is crushed, mixed evenly with wood ash, and stirred at 60℃ for 1 h; after treatment, the mixture is dried at 80℃ to constant weight, then pulverized and passed through an 80-mesh sieve to obtain the sieve-through material, thus obtaining the modified water-retaining agent.

[0028] The amount of corn starch added is 10 parts, deionized water is 50 parts, modified humic acid product is 5 parts, acrylic acid is 20 parts, and wood ash is 1 part; the amount of potassium persulfate initiator added is 0.8% of acrylic acid, and the amount of N,N'-methylenebisacrylamide crosslinking agent added is 0.3% of acrylic acid.

[0029] The binder is bentonite, and the trace element additive is one of zinc sulfate, ferrous sulfate, and borax.

[0030] A production process for mixed organic fertilizer based on livestock and poultry manure includes the following steps: S1: Aerobic fermentation: The livestock and poultry manure is aerobically fermented, the temperature is controlled at 50℃, the pile is turned over once every 24 hours, and fermentation is carried out for 7 days until the moisture content is less than 30% to obtain fermented manure. S2: Premix preparation: Add straw powder, wood ash, modified humic acid, modified water-retaining agent, trace element additives and binder into a mixer in proportion, and mix at a stirring speed of 200 rpm for 10 minutes to obtain premix; S3: Main mixing: Mix the fermented manure obtained in S1 with the premix obtained in S2, mix at a stirring speed of 150 rpm for 15 minutes, and adjust the moisture content of the mixture to 30%; S4: Granulation: The mixture obtained in S3 is fed into a granulator for granulation, and the granulation particle size is controlled to be 2mm. S5: Drying and application of microbial agent: Dry the granules at 50°C for 1 hour until the moisture content is less than 15%; then, after the granules have cooled to room temperature, apply the compound microbial agent evenly to the surface of the granules by spraying. S6: After drying and inoculating with microbial agents, the granules are sieved, and qualified granules with a particle size of 2mm are packaged to obtain mixed organic fertilizer.

[0031] Example 2: A mixed organic fertilizer based on livestock and poultry manure and its production process, comprising the following raw materials by weight: 65 parts livestock and poultry manure, 25 parts straw powder, 6.5 parts wood ash, 15 parts modified humic acid, 7.5 parts alkali-resistant modified compound microbial agent, 5 parts modified water-retaining agent, 4 parts trace element additives, and 4 parts binder. Modified humic acid is obtained by activating and chelating weathered coal with citric acid and neutralizing it with wood ash. The compound microbial agent is composed of Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis compounded and encapsulated. The modified water-retaining agent is obtained by modifying starch-humic acid-grafted acrylic acid copolymer with wood ash.

[0032] The preparation steps of modified humic acid are as follows: Weathered coal is selected as the raw material for humic acid. The weathered coal is crushed using a crusher and passed through a 135-mesh sieve. The sieved powder is placed in a drying oven and dried at 65℃ until the moisture content is ≤8%, obtaining dried humic acid powder. The humic acid powder is mixed with citric acid solution and added to a reaction vessel. Stirring is started, the speed is controlled at 175 rpm, and the temperature is raised to 75℃. The reaction is maintained at this temperature for 2.5 hours. After the reaction is completed, wood ash is slowly added to the system under continuous stirring to adjust the pH value of the system to 7.2. The neutralized slurry is spray-dried (inlet air temperature 190℃, outlet air temperature 85℃) or transferred to a drying oven and dried at 85℃. The dried lumps are crushed and passed through a 110-mesh sieve to obtain the sieve-through material, thus obtaining modified humic acid.

[0033] The citric acid solution has a mass fraction of 6.5%, and the solid-liquid ratio of humic acid powder to citric acid is 1:9.

[0034] The preparation steps of the compound microbial agent are as follows: Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis are mixed and inoculated into a fermentation medium, and fermented at 33℃ and 175 rpm for 36 hours; the fermentation broth is centrifuged and the bacterial cells are collected, then resuspended in sterile physiological saline and concentrated to a bacterial concentration ≥5×10⁻⁶. 10 CFU / mL was used to obtain a concentrated bacterial cell solution. The concentrated bacterial cell solution was mixed with the embedding solution and stirred thoroughly to obtain a mixed solution. The mixed solution was dropped into a calcium chloride solution using a dropper. The droplets formed gel microspheres upon contact with the calcium chloride solution and were allowed to stand for 25 minutes to solidify. The solidified gel microspheres were collected and washed three times with sterile deionized water to remove residual calcium chloride on the surface. Then, they were dehydrated by freeze drying or low-temperature fluidized bed drying (temperature ≤40℃) to obtain the composite bacterial agent.

[0035] Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis were compounded at a live cell ratio of 1:1:1; the embedding solution was sodium alginate solution, and the bacterial concentrate was mixed with the embedding solution at a volume ratio of 1:4; the mass fraction of calcium chloride solution was 2.0%.

[0036] The fermentation medium contained 15 g / L glucose, 7 g / L peptone, 3.5 g / L yeast extract, and 1.5 g / L potassium dihydrogen phosphate. The embedding solution was prepared by dissolving sodium alginate in deionized water to form a 2.5% sodium alginate solution, which was then sterilized at 121°C for 20 min and cooled to room temperature.

[0037] The preparation steps of the modified water-retaining agent are as follows: Corn starch is mixed with deionized water and stirred at 92℃ for 35 min to obtain starch paste, which is then cooled to 52℃; the modified humic acid product is directly added to the starch paste, and the mixture is stirred vigorously (350 rpm) and ultrasonically assisted (300 W power, 20 min) to ensure uniform dispersion, thus obtaining a starch-humic acid mixed base material; acrylic acid is slowly added to the mixed base material while maintaining the temperature at 52℃, and the pH of the system is slowly adjusted to 6.2 with 5% wood ash extract; potassium persulfate initiator and N,N'-methylenebisacrylamide crosslinking agent are added and nitrogen gas is introduced for protection, and the reaction is carried out at 57℃ for 3.5 h to obtain a graft copolymer gel; the obtained gel is crushed, mixed evenly with wood ash, and stirred at 62℃ for 1.2 h; after treatment, it is dried at 82℃ to constant weight, then pulverized and passed through a 90-mesh sieve to obtain the sieve-through material, thus obtaining the modified water-retaining agent.

[0038] The amount of corn starch added is 12.5 parts, deionized water is 60 parts, modified humic acid product is 6.5 parts, acrylic acid is 22.5 parts, and wood ash is 1.5 parts; the amount of potassium persulfate initiator added is 1.0% of acrylic acid, and the amount of N,N'-methylenebisacrylamide crosslinking agent added is 0.4% of acrylic acid.

[0039] The binder is bentonite, and the trace element additive is one of zinc sulfate, ferrous sulfate, and borax.

[0040] A production process for mixed organic fertilizer based on livestock and poultry manure includes the following steps: S1: Aerobic fermentation: The livestock and poultry manure is aerobically fermented, with the temperature controlled at 57℃. The pile is turned over once every 24 hours and fermented for 11 days until the moisture content is less than 30%, thus obtaining fermented manure. S2: Premix preparation: Add straw powder, wood ash, modified humic acid, modified water-retaining agent, trace element additives and binder into a mixer in proportion and mix at a stirring speed of 250 rpm for 15 minutes to obtain premix. S3: Main mixing: Mix the fermented manure obtained in S1 with the premix obtained in S2, mix at a stirring speed of 175 rpm for 22 minutes, and adjust the moisture content of the mixture to 35%; S4: Granulation: The mixture obtained in S3 is fed into a granulator for granulation, and the granulation particle size is controlled to be 3mm. S5: Drying and application of microbial agent: Dry the granules at 55℃ for 1.5h until the moisture content is less than 15%; then, after the granules have cooled to room temperature, apply the compound microbial agent evenly to the surface of the granules by spraying. S6: After drying and inoculating with microbial agents, the granules are sieved, and qualified granules with a particle size of 3mm are packaged to obtain mixed organic fertilizer.

[0041] Example 3: A mixed organic fertilizer based on livestock and poultry manure and its production process, comprising the following raw materials in parts by weight: 70 parts livestock and poultry manure, 30 parts straw powder, 8 parts wood ash, 20 parts modified humic acid, 10 parts alkali-resistant modified compound microbial agent, 7 parts modified water-retaining agent, 5 parts trace element additives, and 5 parts binder. Modified humic acid is obtained by activating and chelating weathered coal with citric acid and neutralizing it with wood ash. The compound microbial agent is composed of Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis compounded and encapsulated. The modified water-retaining agent is obtained by modifying starch-humic acid-grafted acrylic acid copolymer with wood ash.

[0042] The preparation steps of modified humic acid are as follows: Weathered coal is selected as the raw material for humic acid. The weathered coal is crushed using a crusher and passed through a 150-mesh sieve. The sieved powder is placed in a drying oven and dried at 70℃ until the moisture content is ≤8%, obtaining dried humic acid powder. The humic acid powder is mixed with citric acid solution and added to a reaction vessel. Stirring is started, the speed is controlled at 200 rpm, and the temperature is raised to 80℃. The reaction is maintained at this temperature for 3 hours. After the reaction is completed, wood ash is slowly added to the system under continuous stirring to adjust the pH value of the system to 7.5. The neutralized slurry is spray-dried (inlet air temperature 200℃, outlet air temperature 90℃) or transferred to a drying oven and dried at 90℃. The dried lumps are crushed and passed through a 120-mesh sieve to obtain the sieve-through material, thus obtaining modified humic acid.

[0043] The citric acid solution has a mass fraction of 8%, and the solid-liquid ratio of humic acid powder to citric acid is 1:10.

[0044] The preparation steps of the compound microbial agent are as follows: Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis are mixed and inoculated into a fermentation medium, and fermented at 37℃ and 200 rpm for 48 h; the fermentation broth is centrifuged and the bacterial cells are collected, then resuspended in sterile physiological saline and concentrated to a bacterial concentration ≥5×10⁻⁶. 10CFU / mL was used to obtain a concentrated bacterial cell solution. The concentrated bacterial cell solution was mixed with the embedding solution and stirred thoroughly to obtain a mixed solution. The mixed solution was dropped into a calcium chloride solution using a dropper. The droplets formed gel microspheres upon contact with the calcium chloride solution and were allowed to stand for 30 minutes to solidify. The solidified gel microspheres were collected and washed four times with sterile deionized water to remove residual calcium chloride on the surface. Then, they were dehydrated by freeze drying or low-temperature fluidized bed drying (temperature ≤40℃) to obtain the composite bacterial agent.

[0045] Bacillus subtilis, Bacillus mucilaginosus, and Bacillus licheniformis were compounded at a live cell ratio of 1:1:1; the embedding solution was sodium alginate solution, and the bacterial concentrate was mixed with the embedding solution at a volume ratio of 1:5; the mass fraction of calcium chloride solution was 2.5%.

[0046] The fermentation medium contained 20 g / L glucose, 10 g / L peptone, 5 g / L yeast extract, and 2 g / L potassium dihydrogen phosphate. The embedding solution was prepared by dissolving sodium alginate in deionized water to form a 3.0% sodium alginate solution, which was then sterilized at 121°C for 20 min and cooled to room temperature.

[0047] The preparation steps of the modified water-retaining agent are as follows: Corn starch is added to deionized water and mixed, and stirred and gelatinized at 95℃ for 40 min to obtain starch paste, which is then cooled to 55℃; the modified humic acid product is directly added to the starch paste, and stirred vigorously (400 rpm) with ultrasonic assistance (300W power, 20 min) to make it uniformly dispersed to obtain starch-humic acid mixed base material; acrylic acid is slowly added to the mixed base material while maintaining the temperature at 55℃, and the pH value of the system is slowly adjusted to 6.5 with 5% wood ash extract by mass fraction, potassium persulfate initiator and N,N'-methylenebisacrylamide crosslinking agent are added, and nitrogen gas is introduced for protection. The reaction is carried out at 60℃ for 4 h to obtain graft copolymer gel; the obtained gel is crushed, mixed evenly with wood ash, and stirred at 65℃ for 1.5 h; after treatment, it is dried at 85℃ to constant weight, and then pulverized and passed through a 100-mesh sieve to obtain the sieve-through material to obtain the modified water-retaining agent.

[0048] The amount of corn starch added is 15 parts, deionized water is 70 parts, modified humic acid product is 8 parts, acrylic acid is 25 parts, and wood ash is 2 parts; the amount of potassium persulfate initiator added is 1.2% of acrylic acid, and the amount of N,N'-methylenebisacrylamide crosslinking agent added is 0.5% of acrylic acid.

[0049] The binder is bentonite, and the trace element additive is one of zinc sulfate, ferrous sulfate, and borax.

[0050] A production process for mixed organic fertilizer based on livestock and poultry manure includes the following steps: S1: Aerobic fermentation: The livestock and poultry manure is aerobically fermented, the temperature is controlled at 65℃, the pile is turned over once every 24 hours, and fermentation is carried out for 15 days until the moisture content is less than 30% to obtain fermented manure. S2: Premix preparation: Add straw powder, wood ash, modified humic acid, modified water-retaining agent, trace element additives and binder into a mixer in proportion, and mix at a stirring speed of 300 rpm for 20 minutes to obtain the premix. S3: Main mixing: Mix the fermented manure obtained in S1 with the premix obtained in S2, mix at a stirring speed of 200 rpm for 30 minutes, and adjust the moisture content of the mixture to 40%; S4: Granulation: The mixture obtained in S3 is fed into a granulator for granulation, and the granulation particle size is controlled to be 4mm. S5: Drying and application of microbial agent: Dry the granules at 60℃ for 2 hours until the moisture content is less than 15%; then, after the granules have cooled to room temperature, apply the compound microbial agent evenly to the surface of the granules by spraying. S6: After drying and inoculating with microbial agents, the granules are sieved, and qualified granules with a particle size of 4mm are packaged to obtain mixed organic fertilizer.

[0051] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example uses commercially available ordinary weathered coal humic acid powder.

[0052] Comparative Example 2 differs from Example 1 in that it uses commercially available Bacillus subtilis inoculant.

[0053] Comparative Example 3 differs from Example 1 in that it uses commercially available sodium polyacrylate water-retaining agent.

[0054] Performance testing: Performance tests were conducted on the mixed organic fertilizers prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3. Organic matter content test: Under specific heating conditions, the organic carbon in the sample is oxidized by excess potassium dichromate-sulfuric acid solution. The remaining potassium dichromate is titrated with ferrous sulfate standard solution. The organic carbon content is calculated by the difference in volume of ferrous sulfate solution consumed by the blank and the sample. Then, it is multiplied by the empirical constant of 1.724, which characterizes the average composition of organic matter, to finally calculate the organic matter content of the sample. Test standard: NY / T 525-2021 Organic Fertilizer; Microbial agent survival rate test: After aseptic treatment and serial 10-fold dilution of the sample, the appropriate dilution of the bacterial solution was spread on a specific agar plate and incubated at a suitable temperature until colonies grew. The actual number of viable bacteria in the sample was calculated by counting the number of colonies on the plate. Finally, the survival rate of the microbial agent in the final product was calculated by comparing the actual number of viable bacteria in the finished product with the theoretical number of viable bacteria when the microbial agent was added. Test standard: GB 20287-2006 Agricultural Microbial Agents; Humic acid content test: Humic acid was extracted from the sample using sodium hydroxide solution, and then sulfuric acid was added to precipitate and separate the humic acid, thus obtaining purified humic acid; subsequently, the precipitate was determined by potassium dichromate oxidation method, and its organic carbon content was calculated by titration and multiplied by the empirical constant 1.724 to finally obtain the accurate content of humic acid in the sample. Test standard: NY / T 1971-2010.

[0055] The obtained test data are recorded in Table 1 below:

[0056] By comparing and analyzing the relevant data in Table 1, it can be seen that the mixed organic fertilizer prepared by the present invention using a mixed organic fertilizer based on livestock and poultry manure and its production process not only contains high levels of organic matter and humic acid, but also exhibits a high survival rate of the microbial agent. This indicates that the mixed organic fertilizer based on livestock and poultry manure and its production process provided by the present invention have a broader market prospect and are more suitable for promotion.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A mixed organic fertilizer based on livestock manure, characterized by, The following raw materials are included by weight: 60-70 parts of livestock and poultry manure, 20-30 parts of straw powder, 5-8 parts of wood ash, 10-20 parts of modified humic acid, 5-10 parts of compound microbial agent, 3-7 parts of modified water retaining agent, 3-5 parts of trace element additive, and 3-5 parts of binder; The modified humic acid is obtained by activation and chelation of weathered coal with citric acid and neutralization modification of wood ash; The compound microbial agent is obtained by embedding and compounding Bacillus subtilis, Bacillus mycoides and Bacillus licheniformis; The modified water retaining agent is obtained by modification of starch-humic acid grafting acrylic acid copolymer with wood ash.

2. The mixed organic fertilizer based on livestock and poultry manure according to claim 1, characterized in that, The preparation steps of the modified humic acid are as follows: selecting weathered coal as the raw material of humic acid, crushing and sieving, mixing the humic acid powder and the citric acid solution into a reaction kettle, stirring at 70-80 DEG C and 150-200 rpm for 2-3 h, adding wood ash to the system after the reaction is completed, adjusting the pH value of the system to 7.0-7.5, spray drying or transferring to a drying oven at 80-90 DEG C for drying, crushing the blocky material after drying, sieving through a 100-120 mesh sieve to obtain the undersize material, and obtaining the modified humic acid.

3. The mixed organic fertilizer based on livestock and poultry manure according to claim 2, characterized in that: The mass fraction of the citric acid solution is 5-8%, and the solid-liquid ratio of the humic acid powder to the citric acid is 1: (8-10).

4. The mixed organic fertilizer based on livestock and poultry manure according to claim 1, characterized in that, The preparation steps of the compound microbial agent are as follows: compounding Bacillus subtilis, Bacillus mycoides and Bacillus licheniformis, inoculating them into a fermentation medium, and fermenting at 30-37 DEG C and 150-200 rpm for 24-48 h; centrifuging the fermentation liquor, collecting the bacterial cells, resuspending them with sterile normal saline to obtain a bacterial cell concentrate; mixing the bacterial cell concentrate with an embedding solution, stirring uniformly to obtain a mixed solution; using a dripping device to drop the mixed solution into a calcium chloride solution, forming gel microspheres in the instant of contacting the calcium chloride solution, and standing for 20-30 min for solidification; collecting the solidified gel microspheres, and dehydrating by freeze-drying or low-temperature fluidized bed drying to obtain the compound microbial agent.

5. The mixed organic fertilizer based on livestock and poultry manure according to claim 4, characterized in that: The Bacillus subtilis, Bacillus mycoides and Bacillus licheniformis are compounded in a ratio of 1:1:1; the embedding solution is a sodium alginate solution, and the bacterial cell concentrate and the embedding solution are mixed in a volume ratio of 1: (3-5); and the mass fraction of the calcium chloride solution is 1.5-2.5%.

6. The mixed organic fertilizer based on livestock and poultry manure according to claim 4, characterized in that: The fermentation medium comprises 10-20 g / L of glucose, 5-10 g / L of proteose peptone, 2-5 g / L of yeast powder and 1-2 g / L of potassium dihydrogen phosphate; the embedding solution is a sodium alginate solution prepared by dissolving sodium alginate in deionized water to obtain a sodium alginate solution with a mass fraction of 2.0-3.0%, sterilizing at 121 DEG C for 20 min, and cooling to room temperature.

7. The mixed organic fertilizer based on livestock and poultry manure according to claim 1, characterized in that, The preparation steps of the modified water-retaining agent are as follows: corn starch is added into deionized water and mixed, and then stirred and gelatinized at 90-95℃ for 30-40 min to obtain starch paste, and then cooled to 50-55℃; the modified humic acid product is directly added into the starch paste, and then uniformly dispersed by strong stirring and ultrasonic assistance to obtain a starch-humic acid mixed base; the temperature is maintained at 50-55℃, acrylic acid is slowly added into the mixed base, the pH value of the system is slowly adjusted to 6.0-6.5 by using 5% wood ash leaching solution, the initiator potassium persulfate and the crosslinking agent N,N'-methylene bisacrylamide are added, and nitrogen protection is carried out, and then the reaction is carried out at 55-60℃ for 3-4h to obtain a graft copolymerization gel; the obtained gel is crushed and uniformly mixed with wood ash, and then stirred and treated at 60-65℃ for 1-1.5h; after the treatment is completed, the gel is dried at 80-85℃ until the weight is constant, and then crushed to pass through an 80-100 mesh sieve to obtain undersize material to prepare the modified water-retaining agent.

8. The mixed organic fertilizer based on livestock and poultry manure according to claim 7, characterized in that: The corn starch is added in an amount of 10-15 parts, the deionized water is 50-70 parts, the modified humic acid product is 5-8 parts, the acrylic acid is 20-25 parts, and the wood ash is 1-2 parts; the initiator potassium persulfate is added in an amount of 0.8-1.2% of the acrylic acid, and the crosslinking agent N,N'-methylene bisacrylamide is added in an amount of 0.3-0.5% of the acrylic acid.

9. The mixed organic fertilizer based on livestock and poultry manure according to claim 1, characterized in that: The binder is bentonite, and the trace element additive is one of zinc sulfate, ferrous sulfate and borax.

10. A production process of mixed organic fertilizer based on livestock manure, the mixed organic fertilizer based on livestock manure according to any one of claims 1-9, characterized in that, The method comprises the following steps: S1: aerobic fermentation: the livestock and poultry manure is subjected to aerobic fermentation, the temperature is controlled at 50-65℃, the pile is turned over once every 24 hours, and the fermentation is carried out for 7-15 days until the water content is less than 30% to obtain fermented manure; S2: preparation of premix: straw powder, wood ash, modified humic acid, modified water-retaining agent, trace element additive and binder are added into a mixing machine in proportion, and mixed at a stirring speed of 200-300 rpm for 10-20 min to obtain a premix; S3: main mixing: the fermented manure obtained in S1 is mixed with the premix obtained in S2, and the mixture is mixed at a stirring speed of 150-200 rpm for 15-30 min, and the water content of the mixture is adjusted to 30-40%; S4: granulation: the mixture obtained in S3 is sent into a granulator for granulation, and the particle size of the granulation is controlled to be 2-4 mm; S5: drying and application of microbial agent: the granules are dried at 50-60℃ for 1-2h until the water content is less than 15%, and then after the granules are cooled to room temperature, the compound microbial agent is uniformly applied to the surface of the granules by spraying; S6: the granules after drying and inoculation of the microbial agent are screened, and the qualified granules with a particle size of 2-4 mm are packaged to prepare the mixed organic fertilizer.

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