Organic fertilizer and preparation method thereof

Abstract

The application relates to the field of biological fertilizer, in particular to an organic fertilizer and a preparation method thereof. The organic fertilizer is prepared from the following raw materials in parts by weight: dry chicken manure 200-300 parts, straw 100-150 parts, biochar 80-120 parts, compound microbial agent 0.2-0.3 parts, urea 3-8 parts and superphosphate 10-14 parts; the biochar is prepared from one or more of sawdust and corn cob as raw materials. When the organic fertilizer is produced by fermentation of chicken manure, the biochar prepared by compounding sawdust and corn cob is added, a pore structure is introduced into the stack, the physical structure of the fermented material is improved, the gas circulation is promoted, the oxygen distribution of the stack is more uniform, the metabolic demand of more aerobic microorganisms can be met, the anaerobic area is reduced, the effective viable count of the organic fertilizer obtained by promoting aerobic fermentation can reach 2.5-3.7*10 8 CFU.g ‑1 .

Description

Technical Field

[0001] This application relates to the field of bio-fertilizers, and in particular to an organic fertilizer and its preparation method. Background Technology

[0002] Bio-organic fertilizer refers to a type of fertilizer that combines the effects of microbial fertilizer, chemical fertilizer, and organic fertilizer by incorporating specific functional microorganisms with organic materials primarily derived from animal and plant residues (such as livestock and poultry manure and crop straw) that have undergone harmless treatment and fermentation. Among bio-organic fertilizers using livestock and poultry manure as the main raw material, chicken manure bio-organic fertilizer has the best effect in reducing soil heavy metal pollution, significantly improving the form of lead in the soil and reducing its biological activity.

[0003] Chicken manure organic fertilizer is generally made by composting and aerobic fermentation of chicken manure and straw as raw materials with the addition of fermentation agents.

[0004] Regarding the aforementioned technologies, the applicant believes that during the composting process, the compacted structure of the compost pile and the uneven diffusion of oxygen during aerobic fermentation can easily create an anaerobic environment, which affects the organic fertilizer. Summary of the Invention

[0005] In order to improve the fertilizer efficiency of aerobic fermentation in the production of organic fertilizer and reduce the generation of methane gas, this application provides an organic fertilizer and a method for its preparation.

[0006] In the first aspect, this application provides an organic fertilizer, which adopts the following technical solution:

[0007] An organic fertilizer is prepared from the following raw materials in parts by weight: 200-300 parts dried chicken manure, 100-150 parts straw, 80-120 parts biochar, 0.2-0.3 parts compound microbial agent, 3-8 parts urea, and 10-14 parts superphosphate.

[0008] The biochar is prepared from one or more of the following raw materials: sawdust and corn cobs.

[0009] Furthermore, the biochar is prepared from wood chips and corn cobs in a weight ratio of (1.5-3):1.

[0010] By adopting the above technical solution, biochar is added to the fermentation raw materials of organic fertilizer. The combination of sawdust biochar and corn cob charcoal increases the diversity and richness of composting bacteria, increases the abundance of lignocellulose degrading bacteria, and can also increase the organic matter degradation rate and total nitrogen content, as well as the nitrate nitrogen content and humic acid content of the compost pile.

[0011] Furthermore, biochar possesses a rich porous structure. Free space plays a crucial role in aerobic fermentation, influencing the aerobic environment of the compost pile. The addition of biochar increases the pile's bulkiness, facilitating the even diffusion of oxygen within the pile. Introducing a porous structure into the pile improves the physical structure of the fermenting material, promoting gas flow and resulting in a more uniform oxygen distribution. This not only meets the metabolic needs of more aerobic microorganisms but also reduces anaerobic zones. Improved aeration conditions promote microbial activity, leading to increased temperature. Higher temperatures accelerate water loss, which also reduces the pile's density, further facilitating oxygen diffusion. Ultimately, this promotes aerobic fermentation and increases the number of viable bacteria in the organic fertilizer.

[0012] In addition, biochar can absorb gases and alter the fermentation environment, thereby reducing methane production during fermentation and decreasing greenhouse gas emissions.

[0013] Furthermore, the method for preparing the biochar is as follows:

[0014] 1) Crush and dry the sawdust and corn cobs, then mix them to form carbon raw materials;

[0015] 2) Mix the carbon raw material with potassium phosphate to obtain a mixture;

[0016] 3) Microwave catalytic reaction

[0017] The mixture was kept at 25-27℃ for 24-26 hours, then dried at 100-110℃ for 1.5-2 hours, and then reacted in a microwave with a power of 500-700W for 2-2.5 hours under nitrogen as a protective gas to obtain biochar.

[0018] By employing the above-mentioned technical solution, biochar is prepared using a combination of microwave pyrolysis and catalytic reaction. Potassium phosphate can increase the heating rate and reduce the time required for the pyrolysis reaction. Microwave catalytic pyrolysis can accelerate the evaporation of moisture in biomass particles and eliminate volatiles in the pores, thereby increasing the porosity of the biochar. Furthermore, during carbonization, phosphoric acid dehydrates to form polyphosphoric acid, and the generated vapor enters the biomass, promoting the formation of pore structures during pyrolysis. Increasing the porosity of the biochar provides more space for oxygen circulation within the pile, further promoting aerobic fermentation and increasing the number of viable bacteria in the organic fertilizer.

[0019] Furthermore, the biochar preparation method also includes a gas activation step, which is set after the microwave catalytic reaction. The gas activation step is as follows:

[0020] Carbon dioxide was used as the activating gas to react with biochar at a temperature of 700-800℃, a pressure of 300-400 kPa, and a gas flow rate of 0.5-0.8 m / s. 3 / min.

[0021] By adopting the above technical solution, biochar is activated by gas. Carbon dioxide can react with the surface of biochar to generate more pores and surface functional groups, opening and expanding the pores, increasing the porosity, providing more channels for oxygen circulation in the pile, further promoting aerobic fermentation, and increasing the number of effective live bacteria in the organic fertilizer.

[0022] Furthermore, the weight ratio of the carbon raw material to potassium phosphate is 1:(0.1-0.15).

[0023] By employing the above technical solution and limiting the ratio of carbon raw material to potassium phosphate, the porosity of the biochar surface remains at a high level within the range defined in this application, and the pore structure is mainly micropores. If the proportion of potassium phosphate is too high, it may lead to a decrease in the pore volume and specific surface area of ​​the biochar.

[0024] Furthermore, the microwave power is 500W.

[0025] By adopting the above technical solution, the relatively low microwave power allows microwave pyrolysis to proceed at a relatively low heating rate, thereby increasing the proportion of micropores in the pore structure of the biochar surface.

[0026] Secondly, this application provides a method for preparing organic fertilizer, which adopts the following technical solution:

[0027] A method for preparing any of the above-mentioned organic fertilizers includes the following steps:

[0028] S1. Mixing: Mix dry chicken manure, straw, biochar, urea, and superphosphate evenly according to the specified ratio;

[0029] S2. Humidification: Add water to adjust the initial moisture content of the material;

[0030] S3. Stockpile size: The accumulation of materials into a stockpile;

[0031] S4. Inoculation: Inoculate with compound microbial agent:

[0032] S5. Ferment and turn the pile until fermentation is complete.

[0033] Furthermore, in step S2, the initial material moisture content is adjusted to 50-60%.

[0034] By adopting the above technical solution, the moisture content of the initial material is limited. The moisture content can be any one within the range of 50-60%, such as 50%, 55%, or 60%. Within the range defined in this application, the organic fertilizer obtained by aerobic fermentation has a higher number of live bacteria. If the moisture content is too high, water will occupy the pores of the material, replacing air, reducing the activity of aerobic microorganisms and limiting the decomposition rate of organic matter. If the moisture content is too low, the nutrients in the material cannot be fully dissolved, hindering the growth and reproduction of microorganisms.

[0035] Furthermore, the weight of the stack in S3 is 2300-2500 kg.

[0036] By adopting the above technical solution, the size of the compost pile is limited, and the weight of the pile can be any one of 2300-2500 kg, such as 2300 kg, 2400 kg, or 2500 kg. Within the range defined in this application, the number of viable bacteria in the organic fertilizer obtained by aerobic fermentation is higher. If the pile is too large, it will affect aeration, inhibit the activity of aerobic microorganisms, prolong the fermentation cycle, and affect the quality of the bio-organic fertilizer. If the pile is too small, it is not conducive to heat preservation, affecting the activity of microorganisms such as thermophilic fungi, thermophilic actinomycetes, and thermophilic Bacillus, thus affecting the quality of the bio-organic fertilizer.

[0037] Furthermore, the turning frequency in S5 is once every 3 days.

[0038] By adopting the above technical solution, turning the compost pile is to increase aeration. Insufficient aeration will inhibit the activity of aerobic microorganisms, prolong the fermentation cycle, and affect the quality of the bio-organic fertilizer. If the aeration is too strong, microbial activity will be vigorous, organic matter decomposition will be accelerated, and humus accumulation will be reduced. At the same time, excessive aeration will also remove a large amount of heat, affecting the fermentation temperature. This application limits the turning frequency to once every 3 days based on the addition of biochar.

[0039] In summary, this application has the following beneficial effects:

[0040] This application involves adding biochar, a mixture of sawdust and corn, to the fermentation process of chicken manure to produce organic fertilizer. This introduces a porous structure into the compost pile, improving the physical structure of the fermentation material, promoting gas circulation, and resulting in a more uniform oxygen distribution. This not only meets the metabolic needs of more aerobic microorganisms but also reduces anaerobic areas. Improved aeration conditions promote microbial activity, leading to increased temperature. The higher temperature accelerates water loss, which in turn reduces the density of the compost pile, further facilitating oxygen diffusion. The resulting organic fertilizer exhibits an effective viable bacteria count of 2.5-3.7 × 10⁻⁶. 8 CFU·g -1 . Detailed Implementation

[0041] The present application will be further described in detail below with reference to the embodiments.

[0042] Example of raw material and intermediate preparation

[0043] raw material

[0044] All raw materials used in the embodiments of this application are commercially available.

[0045] Trichoderma harzianum, Bacillus subtilis, and Bacillus licheniformis were purchased from Beihai Qiangxing Biotechnology Co., Ltd.

[0046] Urea, industrial grade;

[0047] Potassium phosphate, analytical grade.

[0048] Preparation Example

[0049] Preparation Example 1

[0050] A biochar, the preparation method of which is as follows:

[0051] 1) Crush the sawdust and corn cobs separately, pass them through a 200-mesh sieve, and then dry them at 105℃ for 12 hours. Mix them together, and mix the sawdust and corn cobs in a weight ratio of 1.5:1 to obtain carbon raw material.

[0052] 2) Mix 100 kg of the carbon raw material obtained in step 1) with 0.1 kg of potassium phosphate to obtain a mixture;

[0053] 3) Microwave catalytic reaction

[0054] The mixture was kept at 25°C for 24 hours, then dried at 100°C for 2 hours, and then reacted in a microwave with a power of 500W for 2 hours under nitrogen as a protective gas to obtain biochar.

[0055] Preparation Example 2

[0056] A biochar, the preparation method of which is as follows:

[0057] Unlike Preparation Example 1, in Preparation Example 2, the amount of potassium phosphate used in step 2) is 0.15 kg.

[0058] Preparation Example 3

[0059] A biochar, the preparation method of which is as follows:

[0060] Unlike Preparation Example 1, in Preparation Example 2, the amount of potassium phosphate used in step 2) is 0.2 kg.

[0061] Preparation Example 4

[0062] A biochar, the preparation method of which is as follows:

[0063] Unlike Preparation Example 2, the microwave power in step 3) of Preparation Example 4 is 700W.

[0064] Preparation Example 5

[0065] A biochar, the preparation method of which is as follows:

[0066] Unlike Preparation Example 2, in Preparation Example 5, the weight ratio of sawdust to corn cob in step 1) is 3:1.

[0067] Preparation Example 6

[0068] A biochar, the preparation method of which is as follows:

[0069] Unlike Preparation Example 2, in Preparation Example 6, the weight ratio of sawdust to corn cob in step 1) is 1:2.

[0070] Preparation Example 7

[0071] A biochar, the preparation method of which is as follows:

[0072] 1) Same as Example 2;

[0073] 2) Same as Example 2;

[0074] 3) Same as Example 2;

[0075] 4) Gas activation

[0076] The biochar obtained in step 4) was added to the reactor, and carbon dioxide was used as the activating gas to react with the biochar. The reactor reaction temperature was 700℃, the reaction pressure was 400 kPa, and the gas flow rate was 0.5 m / s. 3 / min.

[0077] Preparation Example 8

[0078] A biochar, the preparation method of which is as follows:

[0079] Unlike Preparation Example 7, Preparation Example 8 involved a reaction temperature of 750°C, a reaction pressure of 350 kPa, and a gas flow rate of 0.7 m³ / s. 3 / min.

[0080] Preparation Example 9

[0081] A biochar, the preparation method of which is as follows:

[0082] Unlike Preparation Example 7, Preparation Example 9 involved a reaction temperature of 800°C, a reaction pressure of 300 kPa, and a gas flow rate of 0.8 m³ / s. 3 / min.

[0083] Preparation Example 10

[0084] Unlike Preparation Example 1, in Preparation Example 10, corn cobs were replaced with an equal amount of sawdust.

[0085] Preparation Example 11

[0086] Unlike Preparation Example 1, Preparation Example 11 used an equal amount of corn cob to replace the sawdust.

[0087] Example

[0088] Examples 1-3

[0089] An organic fertilizer, the preparation method of which is as follows:

[0090] S1. Mixing: Mix dry chicken manure, straw, biochar, urea and superphosphate evenly according to the proportions in Table 1;

[0091] S2. Humidification: Add water to adjust the initial moisture content of the material to 55%;

[0092] S3. Stockpile weight: The material is piled up into a stockpile with a stockpile weight of 2300 kg;

[0093] S4. Inoculation: Inoculate with compound microbial agent:

[0094] S5. Fermentation and turning: Turn the pile once every 3 days until fermentation is complete.

[0095] Table 1. Raw material ratios for Examples 1-3 (kg)

[0096] dried chicken manure 200 250 300 straw 150 130 100 biochar 80 100 120 complex microbial agent 0.2 0.3 0.3 urea 3 5 8 superphosphate 14 12 10

[0097] The compound microbial agent includes Trichoderma harzianum, Bacillus subtilis, and Bacillus licheniformis in a ratio of 1:1:1; the biochar is derived from Preparation Example 1.

[0098] Example 4

[0099] Unlike Example 2, the weight of the stack in Example 4 is 2500 kg.

[0100] Examples 5-12

[0101] Unlike Example 2, the biochar in Examples 5-12 were derived from Preparation Examples 2-9, respectively.

[0102] Comparative Example

[0103] Comparative Example 1

[0104] Unlike Example 1, the biochar in Comparative Example 1 was derived from Preparation Example 10.

[0105] Comparative Example 2

[0106] Unlike Example 1, the biochar in Comparative Example 2 was derived from Preparation Example 11.

[0107] Comparative Example 3

[0108] Unlike Example 1, in Comparative Example 3, an equal amount of straw was used to replace biochar.

[0109] Performance testing

[0110] The performance of the products in the examples and comparative examples was tested, and the test results are shown in Table 2.

[0111] Effective viable bacteria count: determined according to the method in NY / T 2321—2013 "Inspection Procedures for Microbial Fertilizer Products".

[0112] Methane production: The methane release rate was determined by gas chromatography using the static chamber method as specified in GB / T 31705-2015, and the highest methane release rate was recorded.

[0113] Table 2 Performance Test Results

[0114]

[0115]

[0116] Combining Examples 1-12 with Comparative Examples 1-3, and referring to Table 2, it can be seen that the viable bacteria count of the organic fertilizer obtained in Examples 1-12 is higher than that in Comparative Examples 1-3, indicating that the organic fertilizer obtained in Examples 1-12 is of higher quality. Furthermore, during the fermentation process of the organic fertilizer in Examples 1-12, the highest methane release rate is lower than that in Comparative Examples 1-3, indicating that the amount of methane gas produced during the organic fertilizer manufacturing process of this application is relatively smaller. The organic fertilizer produced in this application is of high quality, and the production process generates less methane gas.

[0117] Combining Example 1 and Comparative Examples 1-3, and referring to Table 2, it can be seen that the biochar in Comparative Examples 1 and 2 was single-source biochar, while Comparative Example 3 contained no biochar. Therefore, the viable bacteria count in the organic fertilizers of Comparative Examples 1-3 was significantly lower than that in Example 1, with Comparative Example 3 showing the lowest viable bacteria count. This indicates that adding biochar during the aerobic fermentation of chicken manure to produce organic fertilizer helps increase the viable bacteria count. Furthermore, biochar made from sawdust and corn cobs has a more significant synergistic effect on increasing the viable bacteria count in organic fertilizer. This may be because the combination of sawdust biochar and corn cob charcoal increases the diversity and abundance of composting bacteria, the abundance of lignocellulose-degrading bacteria, and also improves the organic matter degradation rate and total nitrogen content, as well as the nitrate nitrogen and humic acid content of the compost pile. Simultaneously, the addition of biochar introduces a porous structure into the compost pile, improving the physical structure of the fermentation materials, promoting gas flow, and resulting in a more uniform oxygen distribution within the pile. This not only meets the metabolic needs of more aerobic microorganisms but also reduces anaerobic areas. Improved aeration conditions promote microbial activity, leading to increased temperature. The higher temperature accelerates water loss, which also reduces the density of the compost pile, further facilitating oxygen diffusion. This promotes aerobic fermentation and increases the number of effective live bacteria in the organic fertilizer.

[0118] Combining Examples 2 and 4, and referring to Table 2, it can be seen that there is no significant difference in the number of viable bacteria and the highest methane production rate in the organic fertilizer between Examples 2 and 4. This indicates that a pile size of 2300 kg or 2500 kg is applicable to this application, and can be selected according to the actual situation in actual production.

[0119] Combining Examples 2 and 10-12, and referring to Table 2, it can be seen that the number of viable bacteria in the organic fertilizer of Examples 10-12 is higher than that of Example 2. This indicates that gas activation of biochar can further improve the quality of organic fertilizer. This may be because gas activation of biochar allows carbon dioxide to react with the surface of the biochar, generating more pores and surface functional groups, opening and expanding the pores, increasing porosity, providing more channels for oxygen circulation within the compost pile, further promoting aerobic fermentation, and increasing the number of viable bacteria in the organic fertilizer.

[0120] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An organic fertilizer, characterized in that, It is prepared from the following raw materials in parts by weight: 200-300 parts dried chicken manure, 100-150 parts straw, 80-120 parts biochar, 0.2-0.3 parts compound microbial agent, 3-8 parts urea, and 10-14 parts superphosphate; the compound microbial agent includes Trichoderma harzianum, Bacillus subtilis, and Bacillus licheniformis in a weight ratio of 1:1:

1. The biochar is prepared from wood chips and corn cobs in a weight ratio of (1.5-3):1; the preparation method of the biochar is as follows: 1) Crush and dry the sawdust and corn cobs, then mix them to form carbon raw materials; 2) Mix the carbon raw material obtained in step 1) with potassium phosphate at a weight ratio of 1:(0.1-0.15) to obtain a mixture; 3) Microwave catalytic reaction The mixture obtained in step 2) was kept at 25-27℃ for 24-26 h, then dried at 100-110℃ for 1.5-2 h, and then reacted in a microwave with a power of 500W for 2-2.5 h with nitrogen as a protective gas to obtain biochar. 4) Gas activation Carbon dioxide was used as the activating gas to react with the biochar obtained in step 3). The reaction temperature was 700-800℃, the reaction pressure was 300-400 kPa, and the gas flow rate was 0.5-0.8 m / s. 3 / min.

2. A method for preparing organic fertilizer as described in claim 1, characterized in that, Includes the following steps: S1. Mixing: Mix dry chicken manure, straw, biochar, urea, and superphosphate evenly according to the specified ratio; S2. Humidification: Add water to adjust the initial moisture content of the material; S3. Stockpile size: The accumulation of materials into a stockpile; S4. Inoculation: Inoculate with compound microbial agent: S5. Ferment and turn the pile until fermentation is complete.

3. The method for preparing organic fertilizer according to claim 2, characterized in that, In step S2, the initial material moisture content is adjusted to 50-60%.

4. The method for preparing organic fertilizer according to claim 2, characterized in that, The weight of the stack in S3 is 2300-2500 kg.

5. The method for preparing organic fertilizer according to claim 2, characterized in that, The turning frequency in S5 is once every 3 days.

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