Organic fertilizer and low-temperature fermentation method thereof

Abstract

The invention provides an organic fertilizer and a low-temperature fermentation method thereof, and relates to the field of organic fertilizers. Comprising the following steps: S1, uniformly mixing livestock and poultry manure, auxiliary materials and water, adding a complex microbial inoculant, and uniformly mixing to obtain a to-be-fermented mixture; the mass ratio of the livestock and poultry manure to the auxiliary materials to the complex microbial inoculants is 1: (0.2-0.5): (0.1-0.2); s2, piling the to-be-fermented mixture, covering a film, fermenting and turning the pile; wherein the pile height is 1.2-1.4 m, the ventilation amount into the pile is 0.8-1.2 m < 3 > / h.t in the first to fifth days of fermentation, and the ventilation amount into the pile is 1.5-2.0 m < 3 > / h.t in the sixth to tenth days of fermentation; s3, on the 12th-14th day of fermentation, adding a humic acid chelating solution, uniformly stirring, and continuously fermenting for 1-2 days, so as to obtain the organic fertilizer.

Description

Technical Field

[0001] The present invention relates to the field of organic fertilizers, in particular to an organic fertilizer and a low-temperature fermentation method thereof. Background Art

[0002] Organic fertilizer is derived from raw materials such as animal manure and plant fiber through microbial fermentation. It is rich in nutrients and fertility, and long-term use can improve soil quality. Organic fertilizer fermentation is the process of converting organic waste into stable humus through microbial metabolism, combining resource utilization with soil improvement. The key is to control temperature, humidity, ventilation, and carbon-nitrogen ratios to encourage microbial decomposition of organic matter and generate nutrients that can be absorbed by plants.

[0003] Traditional organic fertilizer fermentation cycles typically last 45 to 60 days. Furthermore, they suffer from poor adaptability to low temperatures, with conventional bacterial agents significantly decreasing in activity below 15°C, leading to fermentation stagnation. Furthermore, the process is time-consuming and relies on natural composting, resulting in low humus conversion efficiency. Furthermore, the process is crude, with inappropriate compost turning frequency and aeration design, resulting in low oxygen transfer efficiency.

[0004] Patent CN202410570178.3 discloses an organic fertilizer and its fermentation method and application. Using puffed straw, a composite bacterial strain, and organic solid waste (animal manure) as raw materials, the composite bacterial strain can efficiently decompose easily decomposable organic components in starch and solid waste. This method also maximizes the permeability and heat preservation capabilities of the raw materials, promotes the rapid diffusion and effective utilization of oxygen, accelerates heating and high temperature maintenance after heating, and achieves efficient sterilization and water vapor evaporation. The examples describe an optimal fermentation time of nine days, an organic matter content of 30-40%, and a nitrogen, phosphorus, and potassium content of 4-6% in the organic fertilizer.

[0005] Patent CN201210330949.9 discloses a method for processing fermented chicken manure organic fertilizer and the resulting fermented chicken manure organic fertilizer. The method uses EM bacterial stock solution, straw, and chicken manure as raw materials. The method involves a closed fermentation process for approximately 5-7 days. When the temperature reaches 60-70°C, the compost is turned for the first time. The compost is then turned every three days for a total of three to four times to achieve full fermentation. This method then combines the compost with enoki mushroom waste, humic acid, and a rooting agent for a secondary mixed fermentation process over a period of four to seven days at a temperature of approximately 70°C. The compost is turned twice during this period, and the moisture content is controlled at 40-50%. After full fermentation, the resulting organic fertilizer contains 45% organic matter, 2% nitrogen, 4.7% phosphorus pentoxide, and 2.7% potassium oxide.

[0006] The currently disclosed organic fertilizer fermentation process has disadvantages such as long fermentation time, low fermentation efficiency, and high production cost (professional fermentation equipment). Therefore, it is urgent to provide a fermentation process with short fermentation time, high fermentation efficiency, and low production cost. Summary of the Invention

[0007] The present invention aims to provide a low-temperature fermentation method for organic fertilizer, which can achieve rapid fermentation at low temperature by controlling the oxygen intake during the fermentation process and the composition of the composite bacterial agent, with low production cost and high fermentation efficiency.

[0008] Another object of the present invention is to provide an organic fertilizer which has high fermentation efficiency through low-temperature fermentation, is rich in organic matter content, and has high fertility.

[0009] The present invention solves the technical problem by adopting the following technical solutions.

[0010] In one aspect, an embodiment of the present invention provides a low-temperature fermentation method for organic fertilizer, comprising the following steps:

[0011] S1, mixing livestock and poultry manure, auxiliary materials, and water, then adding the composite bacterial agent, mixing evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite bacterial agent is 1: (0.2-0.5): (0.1-0.2);

[0012] S2, piling the mixture to be fermented into a pile, covering it with film, fermenting it, and turning it over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 0.8-1.2m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 1.5 to 2.0m 3 / h·t;

[0013] S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 to 2 days to obtain organic fertilizer.

[0014] In some embodiments of the present invention, the livestock and poultry manure is one or more of chicken manure, duck manure, cow manure, sheep manure, and pig manure.

[0015] In some embodiments of the present invention, the composite bacterial agent includes a carrier and active bacteria, and the mass ratio of the carrier to the active bacteria is 1:(1.5-2).

[0016] In some embodiments of the present invention, the active bacteria are psychrophilic Bacillus, low-temperature actinomycetes, and facultative anaerobic yeast, and the mass ratio of the three is (1-1.2): (1-1.2): (0.8-1).

[0017] In some embodiments of the present invention, the composite bacterial agent is prepared as follows:

[0018] Mixing facultative anaerobic yeast, water and porous calcium oxide, stirring evenly to obtain a facultative anaerobic yeast suspension; mixing sodium alginate, bentonite, low-temperature actinomycetes and water, stirring evenly to obtain a low-temperature actinomycete suspension; adding psychrophilic Bacillus to the calcium chloride solution, stirring evenly to obtain a psychrophilic Bacillus suspension;

[0019] Under stirring, the psychrophilic bacillus suspension is added dropwise to the facultative anaerobic yeast suspension, and stirring is continued for 10-30 minutes. Then, the low-temperature actinomycete suspension is added dropwise. After the addition is completed, stirring is continued for 5-10 minutes. The mixture is allowed to stand at 5-10°C for 24-48 hours, filtered, washed, dried, and crushed to obtain the composite bacterial agent.

[0020] In some embodiments of the present invention, the mass ratio of the porous calcium oxide, sodium alginate, bentonite and calcium chloride is (0.5-0.8): (0.5-1): (0.2-0.5): (0.1-0.3).

[0021] In some embodiments of the present invention, the auxiliary materials include, by weight, 10-20 parts of corn stalks, 5-10 parts of rice husks, and 5-10 parts of mushroom residues.

[0022] In some embodiments of the present invention, the particle size of the corn stalks in the auxiliary material is 1-3 cm, the particle size of the rice husks is 0.5-1 cm, and the particle size of the mushroom residue is 0.12-0.5 cm.

[0023] On the other hand, an embodiment of the present invention provides an organic fertilizer produced by the above-mentioned low-temperature fermentation method.

[0024] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0025] The low-temperature fermentation method for organic fertilizer provided by the present invention uses livestock and poultry manure and a composite bacterial agent as raw materials to carry out pile fermentation. During the fermentation process, the ventilation volume in the pile is controlled to timely supplement oxygen for microorganisms to ensure the activity of the microorganisms and shorten the fermentation time. After the fermentation is completed, humic acid chelate liquid is added to form chelates with nitrogen, phosphorus, potassium and trace elements generated after fermentation, thereby reducing the loss of effective elements and improving the fertility of the organic fertilizer. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to specific embodiments.

[0028] On the one hand, a method for low-temperature fermentation of organic fertilizer is provided, comprising the following steps:

[0029] S1. Evenly mix livestock and poultry manure, auxiliary materials, and water, then add a composite microbial agent and mix evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite microbial agent is 1:(0.2-0.5):(0.1-0.2); the auxiliary materials, by weight, include: 10-20 parts of corn straw, 5-10 parts of rice husks, and 5-10 parts of mushroom residue.

[0030] S2, piling the mixture to be fermented into a pile, covering it with film, fermenting it, and turning it over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 0.8-1.2m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 1.5 to 2.0 m 3 / h·t;

[0031] S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 to 2 days to obtain organic fertilizer.

[0032] The livestock and poultry manure is one or more of chicken manure, duck manure, cow manure, sheep manure, and pig manure. Preferably, the livestock and poultry manure is a mixture of chicken manure, duck manure, cow manure, and sheep manure in a mass ratio of 1:1:0.5:0.5.

[0033] The composite bacterial agent includes a carrier and an active bacterial strain, and the mass ratio of the carrier to the active bacterial strain is 1: (1.5-2). The active bacterial strains are Bacillus psychrophilus, Actinomyces frigoritolerans, and Saccharomyces cryophilus, and the mass ratio of the three is (1-1.2): (1-1.2): (0.8-1). Among them, Bacillus psychrophilus and Actinomyces frigoritolerans can actively grow in a low-temperature environment. Compared with traditional bacterial strains, the use of such low-temperature bacteria can be fermented at lower temperatures, which improves the fermentation efficiency at low temperatures and shortens the overall fermentation time.

[0034] The composite bacterial agent is prepared as follows:

[0035] The method comprises the following steps: mixing facultative anaerobic yeast, water and porous calcium oxide, and stirring uniformly to obtain a facultative anaerobic yeast suspension; mixing sodium alginate, bentonite, low-temperature actinomycetes and water, and stirring uniformly to obtain a low-temperature actinomycete suspension; adding psychrophilic Bacillus to a calcium chloride solution, and stirring uniformly to obtain a psychrophilic Bacillus suspension; and dropwise adding the psychrophilic Bacillus suspension to the facultative anaerobic yeast suspension under stirring, continuing stirring for 10-30 minutes, and then dropwise adding the low-temperature actinomycete suspension. After the addition is completed, stirring is continued for 5-10 minutes, and the mixture is allowed to stand at 5-10° C. for 24-48 hours, filtered, washed, dried, and crushed to obtain the composite bacterial agent.

[0036] The porous calcium oxide has a large specific surface area, which can accommodate and adsorb facultative anaerobic yeast. Sodium alginate, bentonite, and calcium chloride form a gel that encapsulates the porous calcium oxide, forming a microcapsule structure with porous calcium oxide inside and sodium alginate and bentonite outside. The facultative anaerobic yeast is primarily loaded on the porous calcium oxide, located in the inner layer of the composite inoculant, while the cryogenic actinomycetes and psychrophilic Bacillus are primarily located in the outer layer. When the composite inoculant is used, the cryogenic actinomycetes and psychrophilic Bacillus in the outer layer multiply first. Under the biological metabolism of the microorganisms and the dissolution of water, the sodium alginate and bentonite in the composite inoculant gradually decompose, revealing the facultative anaerobic yeast inside. At this time, the temperature in the pile also rises, making it suitable for the growth of facultative anaerobic yeast. In other words, the encapsulation effect achieves a slow release of the bacteria, increasing their growth rate at low temperatures and thus improving fermentation efficiency.

[0037] The mass ratio of the porous calcium oxide, sodium alginate, bentonite and calcium chloride is (0.5-0.8):(0.5-1):(0.2-0.5):(0.1-0.3).

[0038] The corn stalks in the auxiliary materials have a particle size of 1-3 cm, the rice husks have a particle size of 0.5-1 cm, and the mushroom residue has a particle size of 0.12-0.5 cm. The larger corn stalks serve as a support structure, creating a certain amount of space between the raw materials during the fermentation process, thereby ensuring a high oxygen content within the pile.

[0039] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0040] Example 1

[0041] Prepare composite bacterial agent A as follows:

[0042] The method comprises the following steps: mixing facultative anaerobic yeast, water and porous calcium oxide and stirring them uniformly to obtain a facultative anaerobic yeast suspension, wherein the mass fraction of the porous calcium oxide is 5%; mixing sodium alginate, bentonite, low-temperature actinomycetes and water and stirring them uniformly to obtain a low-temperature actinomycete suspension, wherein the mass fraction of the sodium alginate is 2%; adding psychrophilic Bacillus to a calcium chloride solution and stirring them uniformly to obtain a psychrophilic Bacillus suspension; and adding the psychrophilic Bacillus suspension dropwise to the facultative anaerobic yeast suspension under stirring, continuing stirring for 10 minutes, and then adding the low-temperature actinomycete suspension dropwise. After the addition is completed, stirring is continued for 5 minutes, and the mixture is allowed to stand at 5° C. for 24 hours, filtered, washed, dried, and crushed to obtain the composite bacterial agent A.

[0043] The mass ratio of porous calcium oxide, sodium alginate, bentonite and calcium chloride is 0.8:1:0.2:0.3, the mass ratio of psychrophilic bacillus, low-temperature actinomycetes and facultative anaerobic yeast is 1:1:0.8, and the mass ratio of the carrier to the active bacteria is 1:2.

[0044] Example 2

[0045] Prepare compound bacterial agent B as follows:

[0046] Facultative anaerobic yeast, water and porous calcium oxide are mixed and stirred uniformly to obtain a facultative anaerobic yeast suspension, wherein the mass fraction of the porous calcium oxide is 5%; sodium alginate, bentonite, low-temperature actinomycetes and water are mixed and stirred uniformly to obtain a low-temperature actinomycete suspension, wherein the mass fraction of sodium alginate is 2%; psychrophilic Bacillus is added to a calcium chloride solution and stirred uniformly to obtain a psychrophilic Bacillus suspension; while stirring, the psychrophilic Bacillus suspension is dropwise added to the facultative anaerobic yeast suspension, and stirring is continued for 10 minutes, and then the low-temperature actinomycete suspension is dropwise added, and stirring is continued for 5 minutes after the dropwise addition is completed. The mixture is allowed to stand at 5°C for 24 hours, filtered, washed, dried, and crushed to obtain the composite bacterial agent B.

[0047] The mass ratio of porous calcium oxide, sodium alginate, bentonite and calcium chloride is 0.5:0.5:0.5:0.3, the mass ratio of psychrophilic bacillus, low-temperature actinomycetes and facultative anaerobic yeast is 1.2:1:0.8, and the mass ratio of the carrier to the active bacteria is 1:2.

[0048] Example 3

[0049] Prepare composite bacterial agent C as follows:

[0050] Facultative anaerobic yeast, water and porous calcium oxide are mixed and stirred uniformly to obtain a facultative anaerobic yeast suspension, wherein the mass fraction of the porous calcium oxide is 5%; sodium alginate, bentonite, low-temperature actinomycetes and water are mixed and stirred uniformly to obtain a low-temperature actinomycete suspension, wherein the mass fraction of sodium alginate is 2%; psychrophilic Bacillus is added to a calcium chloride solution and stirred uniformly to obtain a psychrophilic Bacillus suspension; while stirring, the psychrophilic Bacillus suspension is dropwise added to the facultative anaerobic yeast suspension, and stirring is continued for 10 minutes, and then the low-temperature actinomycete suspension is dropwise added, and stirring is continued for 5 minutes after the dropwise addition is completed. The mixture is allowed to stand at 5°C for 24 hours, filtered, washed, dried, and crushed to obtain the composite bacterial agent C.

[0051] The mass ratio of porous calcium oxide, sodium alginate, bentonite and calcium chloride is 0.6:0.8:0.2:0.1, the mass ratio of psychrophilic Bacillus, low-temperature actinomycetes and facultative anaerobic yeast is 1:1.2):1, and the mass ratio of the carrier to the active bacteria is 1:1.5.

[0052] Example 4

[0053] Prepare the fertilizer of the present embodiment as follows:

[0054] S1, mixing livestock and poultry manure, auxiliary materials, and water, then adding composite microbial agent A, and mixing evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite microbial agent is 1:0.5:0.2;

[0055] S2, the mixture to be fermented is piled into a pile, covered with film, and fermented. When the temperature inside the pile is detected to be higher than 45°C, the pile is turned over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 1.2m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 1.5m 3 / h·t;

[0056] S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 day to obtain organic fertilizer.

[0057] The auxiliary materials added in step S1 include: 20 parts corn stalks, 10 parts rice husks, and 5 parts mushroom residues, wherein the corn stalks have a particle size of 1-3 cm, the rice husks have a particle size of 0.5-1 cm, and the mushroom residues have a particle size of 0.12-0.5 cm. The livestock and poultry manure is a mixture of chicken manure, duck manure, cow manure, and sheep manure, with a mass ratio of 1:1:0.5:0.5.

[0058] Example 5

[0059] Prepare the fertilizer of the present embodiment as follows:

[0060] S1, mixing livestock and poultry manure, auxiliary materials, and water, then adding composite microbial agent B, and mixing evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite microbial agent is 1:0.2:0.1;

[0061] S2, piling the mixture to be fermented into a pile, covering it with film, fermenting it, and turning it over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 0.8m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 1.5m 3 / h·t;

[0062] S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 day to obtain organic fertilizer.

[0063] The auxiliary materials added in step S1 include: 10-20 parts corn stalks, 5-10 parts rice husks, and 5-10 parts mushroom residues, wherein the particle size of the corn stalks is 1-3 cm, the particle size of the rice husks is 0.5-1 cm, and the particle size of the mushroom residue is 0.12-0.5 cm. The livestock and poultry manure is a mixture of chicken manure, duck manure, cow manure, and sheep manure, with a mass ratio of 1:1:0.5:0.5.

[0064] Example 6

[0065] Prepare the fertilizer of the present embodiment as follows:

[0066] S1, mixing livestock and poultry manure, auxiliary materials, and water, then adding composite bacterial agent C, mixing evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite bacterial agent is 1:0.3:0.15;

[0067] S2, piling the mixture to be fermented into a pile, covering it with film, fermenting it, and turning it over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 1.2m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 2.0m 3 / h·t;

[0068] S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 day to obtain organic fertilizer.

[0069] The auxiliary materials added in step S1 include: 10 parts corn stalks, 10 parts rice husks, and 5 parts mushroom residues, wherein the particle size of the corn stalks is 1-3 cm, the particle size of the rice husks is 0.5-1 cm, and the particle size of the mushroom residue is 0.12-0.5 cm. The livestock and poultry manure is a mixture of chicken manure, duck manure, cow manure, and sheep manure, with a mass ratio of 1:1:0.5:0.5.

[0070] Example 7

[0071] Prepare the fertilizer of the present embodiment as follows:

[0072] S1, mixing livestock and poultry manure, auxiliary materials, and water, then adding composite microbial agent A, and mixing evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite microbial agent is 1:0.5:0.2;

[0073] S2, piling the mixture to be fermented into a pile, covering it with film, fermenting it, and turning it over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 1.2m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 2.0m 3 / h·t;

[0074] S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 day to obtain organic fertilizer.

[0075] The auxiliary materials added in step S1 include: 20 parts corn stalks, 10 parts rice husks, and 10 parts mushroom residues, wherein the corn stalks have a particle size of 1-3 cm, the rice husks have a particle size of 0.5-1 cm, and the mushroom residues have a particle size of 0.12-0.5 cm. The livestock and poultry manure is a mixture of chicken manure, duck manure, cow manure, and sheep manure, with a mass ratio of 1:1:0.5:0.5.

[0076] Comparative Example 1

[0077] The difference from Example 4 is that the psychrophilic Bacillus, low-temperature actinomycetes, and facultative anaerobic yeast are directly coated in a mass ratio of 1:1:0.8, mixed with livestock and poultry manure and auxiliary materials, and then fermented. The remaining raw material preparation and fermentation method are the same as those in Example 4.

[0078] Comparative Example 2

[0079] The difference from Example 4 is that no ventilation treatment is performed during the fermentation process, and the remaining raw materials and steps are the same as those in Example 4.

[0080] Experimental example

[0081] The organic fertilizers of Examples 4-7 and Comparative Examples 1-2 were used as test objects to test the contents of organic matter, nitrogen, phosphorus, and potassium in each group of organic fertilizers. The results are shown in Table 1.

[0082] Table 1

[0083] organic matter nitrogen phosphorus potassium Example 4 41 2.5 5.1 2.6 Example 5 42 2.6 5.3 2.8 Example 6 41 2.8 5.4 2.3 Example 7 40 2.6 5.2 2.1 Comparative Example 1 35 1.5 3.5 2.3 Comparative Example 2 25 1.3 3.6 2.4

[0084] As can be seen from Table 1, the organic fertilizers prepared by implementing 4-7 of the present invention are rich in organic matter content, i.e., high fermentation efficiency, and the microbial agent can effectively decompose feces and auxiliary materials. In Comparative Example 1, the microbial agent is directly added to the raw material for fermentation, and its reproduction rate is poorer than that of the embodiment, and the activity of the microorganism is poor, and the corresponding fermentation effect is also poor, and the microorganism cannot effectively decompose feces and auxiliary materials, resulting in less organic matter available in the organic fertilizer.

[0085] In summary, the low-temperature fermentation method for organic fertilizer provided by the present invention uses livestock and poultry manure and a composite bacterial agent as raw materials for pile fermentation. During the fermentation process, the ventilation volume in the pile is controlled to timely supplement oxygen for the microorganisms to ensure the activity of the microorganisms and shorten the fermentation time. After the fermentation is completed, the addition of a humic acid chelate liquid can form chelates with nitrogen, phosphorus, potassium and trace elements generated after fermentation, thereby reducing the loss of effective elements and improving the fertility of the organic fertilizer.

[0086] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

Claims

1. A low-temperature fermentation method for organic fertilizer, characterized in that: The following steps are involved: S1, mixing livestock and poultry manure, auxiliary materials, and water, then adding the composite bacterial agent, mixing evenly to obtain a mixture to be fermented; the mass ratio of livestock and poultry manure, auxiliary materials, and composite bacterial agent is 1: (0.2-0.5): (0.1-0.2); S2, piling the mixture to be fermented into a pile, covering it with film, fermenting it, and turning it over; wherein the pile height is 1.2-1.4m, and on the 1st to 5th day of fermentation, the ventilation volume into the pile is 0.8-1.2m 3 / h·t, on the 6th to 10th day of fermentation, the ventilation rate into the pile is 1.5 to 2.0 m 3 / h·t; S3. On the 12th to 14th day of fermentation, add humic acid chelate solution, stir evenly, and continue fermenting for 1 to 2 days to obtain organic fertilizer.

2. organic fertilizer low-temperature fermentation method according to claim 1, is characterized in that, The livestock and poultry manure is one or more of chicken manure, duck manure, cow manure, sheep manure and pig manure.

3. organic fertilizer low-temperature fermentation method according to claim 1, is characterized in that, The composite bacterial agent comprises a carrier and active bacterial strains, and the mass ratio of the carrier to the active bacterial strains is 1:(1.5-2).

4. organic fertilizer low-temperature fermentation method according to claim 3, is characterized in that, The active bacteria species are psychrophilic bacillus, low-temperature actinomycetes and facultative anaerobic yeast, and the mass ratio of the three is (1-1.2): (1-1.2): (0.8-1).

5. organic fertilizer low-temperature fermentation method according to claim 3, is characterized in that, The composite bacterial agent is prepared as follows: Mixing facultative anaerobic yeast, water and porous calcium oxide, stirring evenly to obtain a facultative anaerobic yeast suspension; mixing sodium alginate, bentonite, low-temperature actinomycetes and water, stirring evenly to obtain a low-temperature actinomycete suspension; adding psychrophilic Bacillus to the calcium chloride solution, stirring evenly to obtain a psychrophilic Bacillus suspension; Under stirring, the psychrophilic bacillus suspension is added dropwise to the facultative anaerobic yeast suspension, and stirring is continued for 10-30 minutes. Then, the low-temperature actinomycete suspension is added dropwise. After the addition is completed, stirring is continued for 5-10 minutes. The mixture is allowed to stand at 5-10°C for 24-48 hours, filtered, washed, dried, and crushed to obtain the composite bacterial agent.

6. organic fertilizer low-temperature fermentation method according to claim 5, is characterized in that, The mass ratio of the porous calcium oxide, sodium alginate, bentonite and calcium chloride is (0.5-0.8):(0.5-1):(0.2-0.5):(0.1-0.3).

7. organic fertilizer low-temperature fermentation method according to claim 1, is characterized in that, The auxiliary materials include, by weight: 10-20 parts of corn straw, 5-10 parts of rice husks, and 5-10 parts of mushroom residues.

8. organic fertilizer low-temperature fermentation method according to claim 7, is characterized in that, The particle size of the corn straw in the auxiliary material is 1-3 cm, the particle size of the rice husk is 0.5-1 cm, and the particle size of the mushroom residue is 0.12-0.5 cm.

9. An organic fertilizer, characterized in that The product is prepared by the low-temperature fermentation method according to any one of claims 1 to 8.