Bio-organic fertilizer and application thereof

Abstract

This invention discloses a bio-organic fertilizer, its preparation method, and its application, belonging to the field of bio-organic fertilizer technology. The invention separates dead silkworms and / or silkworm moths into two parts. The first part undergoes preservation, sterilization, and modification treatments, causing partial hydrolysis of proteins into small peptides and free amino acids, and degradation of chitin into chitosan oligosaccharides, yielding modified silkworm body material. The second part undergoes carbonization treatment to obtain silkworm biochar. The modified silkworm body material, silkworm biochar, and silkworm excrement are compounded in a weight ratio of (10-40):(10-40):(50-80), inoculated with a compound microbial agent, and subjected to aerobic fermentation to obtain the bio-organic fertilizer. This invention achieves the synergistic utilization of dead silkworms, silkworm moths, and silkworm excrement for the first time, overcoming the technical prejudice that dead silkworms "can only be discarded." The product has a total nitrogen content of 5%-7%, possessing both a readily available nitrogen source and the plant immune-inducing function of chitosan oligosaccharides, realizing the complete closed-loop utilization of silkworm breeding waste. This invention can be widely applied to the planting of mulberry trees, rice, rapeseed, corn, wheat, sugarcane, beans, and other cash crops.

Description

Technical Field

[0001] This invention belongs to the field of bio-organic fertilizer technology, specifically relating to a bio-organic fertilizer and its application. Background Technology

[0002] my country is the world's largest silkworm-raising country, with mulberry orchards exceeding 12 million mu (approximately 800,000 hectares). Its annual silkworm rearing volume accounts for over 70% of the world's total, and its cocoon production has ranked first globally for many consecutive years. The silkworm rearing process generates a large amount of waste, mainly including silkworm excrement and the remains of dead silkworms and moths. Statistics show that approximately 600 kg of silkworm rearing waste is generated for every 100 kg of cocoons produced, with an annual national output exceeding 3 million tons. Improper handling of this waste not only wastes resources but also causes serious environmental pollution and the spread of silkworm diseases.

[0003] Silkworm excrement, a major waste product of silkworm farming, is widely used in organic fertilizer production due to its rich organic matter and nutrients such as nitrogen, phosphorus, and potassium. For example, CN102910945A discloses an organic fertilizer converted from waste silkworm excrement and its production method, which involves fermenting silkworm excrement with brown sugar water, lactic acid bacteria, and yeast. CN104230420B discloses a method for rapidly fermenting silkworm excrement organic fertilizer, which completes fermentation within 10-20 hours by adding compound microbial agents.

[0004] CN107673927A discloses a slow-release fertilizer for rice and its preparation method, the raw materials of which include silkworm excrement and plant straw, and the straw is carbonized and then compounded with organic materials. CN112661582A discloses a bio-organic fertilizer and its preparation method, the raw materials of which include modified organic fertilizer base and modified biochar, wherein the modified organic fertilizer base is obtained by mixing organic powder, wood ash, and livestock and poultry manure, followed by inactivation and modification. All of the above technologies use silkworm excrement as the main raw material, realizing the resource utilization of silkworm excrement.

[0005] However, the resource utilization of silkworm waste such as dead silkworms and moths has long been neglected. During silkworm rearing, a considerable number of dead silkworms and moths, due to disease, natural death, or after molting, are discarded, accounting for approximately 10%-20% of the total waste. These silkworm wastes have the following characteristics: First, they have extremely high protein content, with crude protein content reaching 50%-70% in dry matter, and also contain 5%-15% chitin, making them a high-quality source of organic nitrogen and bioactive substances. Second, they carry a large number of pathogenic microorganisms, such as Beauveria bassiana and nucleopolyhedrovirus; if directly discarded or returned to the field, they will pollute the soil and water sources, leading to the spread of silkworm diseases. Third, they decompose extremely quickly, starting to rot and smell within hours of collection, making them difficult to store and transport. Fourth, their carbon-to-nitrogen ratio (C / N) is too low (approximately 5:1), and fermentation alone easily produces ammonia gas, inhibiting proper decomposition.

[0006] For the reasons mentioned above, dead silkworms and silkworm moths have long been considered "hazardous waste" and discarded or incinerated. As clearly stated in the background technology of CN102910945A: "The feces have a high protein content. Pathogens use silkworm feces as nutrients to multiply, leading to the death of some silkworm pupae. Silkworm pupae have even higher protein content, thus causing pathogens to multiply even faster. If used as fertilizer, plants will suffer severe disease... therefore, silkworm feces can only be discarded." This statement fully reflects the long-standing technical bias in this field—dead silkworms are considered unusable for fertilizer production because they carry pathogens and decompose extremely quickly.

[0007] A few studies have attempted to prepare fertilizer using live fifth-instar silkworms as raw materials. For example, CN102584452A and CN106747681A disclose a method for preparing bio-antibacterial organic fertilizer using immune-induced biotechnology. The raw material is natural fifth-instar silkworms (live), prepared through complex biotechnologies such as immune induction and gene regulation. However, both of these patent applications were rejected or withdrawn. Furthermore, their raw material is live silkworms, not dead silkworms / moths from aquaculture waste. The technical route is complex, costly, and difficult to promote and apply.

[0008] In summary, the existing technology has the following shortcomings: 1. The technology for using silkworm excrement as organic fertilizer is relatively mature, but none of them involve the utilization of silkworm waste such as dead silkworms and silkworm moths; 2. Dead silkworms and silkworm moths have long been regarded as "hazardous waste" and have not been utilized as resources due to problems such as carrying pathogens, rapid decomposition, and C / N ratio imbalance, which reflects technological bias. 3. A small number of technical solutions involving silkworms use live silkworms as raw materials, have complex technical routes, and have not been authorized; 4. Existing technologies do not reveal the technical solutions for preparing bio-organic fertilizer by preserving, modifying, or carbonizing dead silkworms and moths and then mixing them with silkworm excrement, nor do they reveal the functional mechanism by which the chitin degradation products of silkworm bodies induce plant systemic resistance.

[0009] Therefore, developing a bio-organic fertilizer that can utilize the waste of dead silkworms and moths while fully leveraging their high protein and chitin resources, and its preparation method, has significant practical importance and application value. Summary of the Invention

[0010] In order to overcome the problems existing in the background art, the present invention provides a bio-organic fertilizer and its application.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solution: A bio-organic fertilizer, wherein the raw materials of the bio-organic fertilizer are composed of the following components: modified silkworm body material, silkworm body biochar and silkworm excrement; The modified silkworm body material is prepared from the dead silkworms and / or silkworm moths of the first part through preservation and modification treatment. The preservation treatment reduces the moisture content of the dead silkworms and / or silkworm moths to below 30% or the pH value to below 5.5. The modification treatment partially hydrolyzes the proteins in the dead silkworms and / or silkworm moths into small molecule peptides and free amino acids, and exposes or partially degrades the chitin structure into chitosan oligosaccharides. The silkworm body biochar is prepared from the dead silkworms and / or silkworm moths of the second part through carbonization treatment. The weight ratio of the modified silkworm body material, the silkworm body biochar and the silkworm excrement is (10~40):(10~40):(50~80).

[0012] Preferably, the modification treatment is an enzymatic hydrolysis treatment, and the enzyme used is selected from protease and chitinase; or, the modification treatment is a high temperature and high pressure treatment, with a treatment temperature of 100-130℃, a pressure of 0.1-0.3 MPa, and a treatment time of 30-120 minutes.

[0013] Preferably, the carbonization process is carried out under oxygen-free or oxygen-limited conditions, with a carbonization temperature of 400-600℃ and a carbonization time of 1-3 hours.

[0014] A method for preparing a bio-organic fertilizer includes the following steps: (1) The collected dead silkworms and / or silkworm moths are screened, and impurities other than dead silkworms and / or silkworm moths are removed, and the collection is divided into a first part and a second part; (2) The first part is subjected to preservation treatment to reduce the moisture content of dead silkworms and / or silkworm moths to below 30% or the pH value to below 5.5, so as to obtain stable silkworm material; (3) The stable silkworm body material obtained in step (2) is sterilized at a temperature of 70-90℃ for 24-72 hours. (4) The sterilized silkworm body material obtained in step (3) is modified to partially hydrolyze the protein in the dead silkworm and / or silkworm moth into small molecule peptides and free amino acids, and expose or partially degrade the chitin structure into chitosan oligosaccharide to obtain modified silkworm body material. (5) Carbonize the second part at a temperature of 400-600℃ for 1-3 hours. After cooling, crush the material to obtain silkworm biochar. (6) Mix the modified silkworm material obtained in step (4), the silkworm biochar obtained in step (5), and silkworm excrement in a weight ratio of (10-40):(10-40):(50-80). Adjust the C / N ratio to 25-35:1 and the moisture content to 50%-65%. (7) Inoculate the mixture obtained in step (6) with compound microbial agent and carry out aerobic fermentation at a temperature of 50-70℃ for 7-20 days; (8) Dry, crush and sieve the fermented and decomposed material to obtain bio-organic fertilizer.

[0015] Preferably, the modification treatment in step (4) is an enzymatic hydrolysis treatment, in which the sterilized silkworm material is mixed with protease and chitinase and enzymatically hydrolyzed for 2-8 hours at pH 6.0-8.0 and temperature 45-60℃; or, the modification treatment in step (4) is a high temperature and high pressure treatment, in which the treatment temperature is 110-120℃, the pressure is 0.15-0.25 MPa, and the treatment time is 45-90 minutes.

[0016] Preferably, the compound microbial agent in step (7) contains Bacillus subtilis and thermococcus, and the inoculation amount is 0.5%-2% of the total weight of the mixture.

[0017] The application of a bio-organic fertilizer in the planting of mulberry, rice, rapeseed, corn, wheat, sugarcane, beans or cash crops is characterized in that the bio-organic fertilizer is applied directly or after secondary formulation according to the nutritional needs of different crops; the secondary formulation includes at least one of the following formulation methods: adding potassium fertilizer for crops with high potassium requirements, adding calcium source for crops with high calcium requirements, and adding carbon source regulator for crops with low nitrogen requirements.

[0018] Preferably, the potassium fertilizer is selected from at least one of potassium sulfate, potassium chloride, and wood ash, and the amount added is 5%-20% of the total weight of the bio-organic fertilizer; the calcium source is selected from at least one of shell powder, oyster shell powder, gypsum, and lime, and the amount added is 5%-30% of the total weight of the bio-organic fertilizer; the carbon source regulator is selected from at least one of straw powder, rice husk, and biochar, and the amount added is 10%-40% of the total weight of the bio-organic fertilizer.

[0019] Preferably, the crops with high potassium requirements include sugarcane, potatoes, tobacco, and bananas; the crops with high calcium requirements include peanuts, soybeans, tomatoes, and apples; and the crops with low nitrogen requirements include legumes.

[0020] Preferably, the secondary formulation further includes: adding an acid regulator for crops that prefer acidic soil, wherein the acid regulator is selected from at least one of sulfur powder and ferrous sulfate, and the addition amount is 1%-5% of the total weight of the bio-organic fertilizer; and adding an alkaline regulator for crops that prefer alkaline soil, wherein the alkaline regulator is selected from at least one of lime and wood ash, and the addition amount is 2%-10% of the total weight of the bio-organic fertilizer.

[0021] The advantages of this invention compared to the prior art are as follows: 1. This invention is the first to use dead silkworms and moths from livestock waste as the main raw materials, compounding them with silkworm excrement to prepare bio-organic fertilizer, filling a gap in this technological direction. The dry matter of dead silkworms and moths has a crude protein content as high as 50%-70% and a chitin content of 5%-15%, making it a high-quality source of organic nitrogen and bioactive substances. After being compounded with silkworm excrement, the total nitrogen content of the product can reach 5%-7%, significantly higher than that of ordinary organic fertilizers (2%-4%).

[0022] 2. Existing technologies generally hold that dead silkworms, due to carrying pathogens and decomposing extremely quickly, "must be discarded," reflecting a long-standing technological bias. This invention systematically overcomes this bias through the following technical means: Preservation treatment (dehydration or acidification) reduces the moisture content of silkworm materials to below 30% or the pH value to below 5.5, inhibiting microbial activity and achieving long-term stable storage (stable storage for more than 90 days at room temperature). Sterilization treatment (70-90℃, 24-72 hours) thoroughly kills pathogenic microorganisms such as Beauveria bassiana and nucleopolyhedrovirus, ensuring product safety; Modification treatment (enzymatic hydrolysis or high temperature and pressure) partially hydrolyzes proteins and activates chitin, transforming "hazardous waste" into high-value fertilizer raw materials.

[0023] The combined application of the above-mentioned technologies has, for the first time, enabled the safe and resource-efficient utilization of dead silkworms, overcoming long-standing technological biases.

[0024] 3. In this invention, dead silkworms / moths are separated into two parts, which are then subjected to modification and carbonization treatments respectively: The first part involves the preparation of modified silkworm body material through modification treatment (enzymatic hydrolysis or high temperature and pressure) to provide a fast-acting nitrogen source (small molecule peptides and free amino acids) and a chitin disease resistance inducer (chitosan oligosaccharide). The second part involves carbonization treatment (400-600℃, 1-3 hours) to prepare silkworm biochar, providing a slow-release carbon source, ammonia adsorbent, and microbial carrier.

[0025] The C / N ratio of silkworm biochar is 20-50:1, and the specific surface area is 150-350 m² / g. It can adsorb ammonia produced during fermentation, reducing nitrogen loss by more than 30%. At the same time, it provides an attachment carrier for microorganisms, promoting the colonization of functional bacteria. Compared with existing technologies that use exogenous wood residue charcoal, this invention achieves complete self-sufficiency in raw materials, forming a perfect closed loop of "mulberry → silkworm → fertilizer → mulberry".

[0026] 4. Existing organic fertilizers primarily use slow-release nitrogen, which requires microbial mineralization before it can be absorbed by plants. This invention modifies silkworm protein to partially hydrolyze (hydrolysis rate 30%-50%), resulting in a product containing both large-molecule proteins (slow-release nitrogen source) and small-molecule peptides and free amino acids (quick-release nitrogen source), forming a dual nitrogen supply system of "quick-release + slow-release". Quick-release nitrogen can be directly absorbed by plant roots, meeting the needs of early crop growth; slow-release nitrogen is continuously released, meeting the needs of mid-to-late stage crop growth, reducing nitrogen loss, and improving nitrogen fertilizer utilization. Detailed Implementation

[0027] To make the objectives, technical solutions, and beneficial effects of the present invention clearer, the preferred embodiments of the present invention will be described in detail below to facilitate understanding by those skilled in the art.

[0028] Example 1: Raw material screening and preservation treatment A total of 100 kg of fresh dead silkworms and silkworm moths (fifth instar mature silkworms and silkworm moths 1-3 days after emergence) were collected from a silkworm breeding base in Yunnan. After removing impurities such as mulberry branches and bedding, 95 kg of pure silkworm body material was obtained. The pure silkworm body material was divided into a first part (60 kg) and a second part (35 kg).

[0029] The first batch of silkworm material was placed in a hot air drying oven and dried at 65℃ for 8 hours until the moisture content dropped to 12%, yielding 58 kg of stable silkworm material. Sampling and testing showed a moisture content of 11.8%, a volatile basic nitrogen (TVB-N) content of 32 mg / 100g, and a total microbial count <10³ CFU / g, indicating a stable state. The stabilized silkworm material was sealed and stored at room temperature (25±5℃) for 90 days, with samples taken every 15 days. All indicators remained within a stable range, demonstrating that the preservation treatment can stably store the silkworm material for more than 90 days.

[0030] Example 2: Sterilization treatment 50 kg of the stable silkworm material obtained in Example 1 was placed in an autoclave and sterilized at 85°C for 48 hours. After sterilization, samples were taken for testing. Beauveria bassiana and nucleopolyhedrovirus were not detected, and the total microbial count was <10² CFU / g, indicating thorough sterilization.

[0031] Example 3: Enzymatic modification treatment 50 kg of sterilized silkworm material obtained in Example 2 was added to 200 kg of water, and the pH was adjusted to 7.0. 1.0 kg of neutral protease (100,000 U / g activity) and 0.2 kg of chitinase (50,000 U / g activity) were added, and the mixture was stirred at 55°C for 4 hours for enzymatic hydrolysis. During the hydrolysis process, samples were taken every 30 minutes to detect the free amino acid content. When the free amino acid content reached 5.2% (dry basis), the temperature was raised to 90°C and held for 15 minutes to inactivate the enzymes. The mixture was centrifuged, and the solid portion was dried at 65°C to a moisture content of 12%, then pulverized to 50 mesh to obtain 48 kg of modified silkworm material.

[0032] The modified silkworm material was tested and found to have a protein hydrolysis rate of 42%, a small molecule peptide content of 18.5%, a free amino acid content of 6.2%, a chitin degradation rate of 15%, and a chitosan oligosaccharide content of 1.8%.

[0033] Example 4: High-temperature and high-pressure modification treatment (alternative to Example 3) 50 kg of sterilized silkworm carcass material obtained in Example 2 was placed in a high-temperature and high-pressure reactor, saturated steam was introduced, the temperature was raised to 115°C, and the pressure was maintained at 0.2 MPa for 60 minutes. The pressure was then rapidly released, causing the material to expand. After removal, it was dried at 65°C to a moisture content of 12%, and then pulverized to 50 mesh to obtain 47 kg of modified silkworm carcass material.

[0034] The modified silkworm material tested showed a protein hydrolysis rate of 35%, a small molecule peptide content of 12.3%, a free amino acid content of 4.5%, a chitin degradation rate of 8%, and a chitosan oligosaccharide content of 0.9%. This method simultaneously sterilizes and modifies the material, making the process simpler.

[0035] Example 5: Carbonization treatment 35 kg of the second batch of silkworm carcass material obtained in Example 1 was placed in a carbonization furnace and heated to 500°C under nitrogen protection, and held at that temperature for 2 hours for carbonization. After cooling, the material was removed, pulverized to 100 mesh, and 28 kg of silkworm biochar was obtained.

[0036] The biochar from silkworms was analyzed to have the following characteristics: specific surface area 235 m² / g, C content 58.3%, N content 2.8%, C / N ratio 20.8, and pH value 9.2. Scanning electron microscopy revealed abundant microporous and mesoporous structures.

[0037] Example 6A: Compound Mixing and Fermentation (Introduction of External Carbon Source) 15 kg of modified silkworm carcass material obtained in Example 3, 25 kg of silkworm biochar obtained in Example 5, and 60 kg of silkworm excrement were mixed in a weight ratio of 15:25:60. 10 kg of rice bran (C / N ratio approximately 40:1) was added to adjust the C / N ratio, and an appropriate amount of water was added to adjust the moisture content to 60%. The mixed material was tested, and the C / N ratio was found to be 26:1, meeting the requirements for aerobic fermentation.

[0038] Inoculate the mixture with a compound microbial agent (Bacillus subtilis and Thermococcus thermophilus, mixed in a 1:1 ratio), at a rate of 1% of the total weight of the mixture. Use windrow composting, controlling the pile temperature at 60-65℃, turning the pile every 3 days, and fermenting for 12 days. Fermentation is complete when the pile temperature drops to ambient temperature, the pH stabilizes at 7.2, there is no odor, and the pile is brownish and loose.

[0039] The fermented and decomposed material is dried at 60℃ to a moisture content of 18%, then crushed and passed through a 100-mesh sieve to obtain the finished bio-organic fertilizer.

[0040] Product Testing The bio-organic fertilizer obtained in Example 6A was tested: Total nitrogen content: 5.8% Small molecule peptides + free amino acids content: 12.6% Chitin + Chitosan Oligosaccharide Content: 1.2% Organic matter content: 58% Effective viable bacteria count: 0.8 billion / g Moisture content: 16% pH value: 7.1 Fecal coliform count: <30 CFU / g Ascaris egg mortality rate: 100% All indicators meet the national standards for bio-organic fertilizer (NY / T 884-2012).

[0041] Example 6B: Compound mixing and fermentation (without external carbon source) 10 kg of the modified silkworm material obtained in Example 3, 30 kg of silkworm biochar obtained in Example 5, and 60 kg of silkworm excrement were mixed together in a weight ratio of 10:30:60 (which conforms to the range of 10-40:10-40:50-80 as defined in claim 1). The total weight of the mixture was 100 kg, without adding any external carbon source.

[0042] The carbon and nitrogen contents of each component were tested and are as follows: Modified silkworm body material: total carbon 42.5%, total nitrogen 3.8%, C / N ratio 11.2:1 Silkworm biochar: total carbon 58.3%, total nitrogen 2.8%, C / N ratio 20.8:1 Silkworm excrement: total carbon 38.5%, total nitrogen 1.6%, C / N ratio 24.1:1 Calculate the total carbon and total nitrogen content of the mixture: Total carbon = 10 × 42.5% + 30 × 58.3% + 60 × 38.5% = 4.25 + 17.49 + 23.10 = 44.84 kg Total nitrogen = 10 × 3.8% + 30 × 2.8% + 60 × 1.6% = 0.38 + 0.84 + 0.96 = 2.18 kg C / N ratio = 44.84 / 2.18 ≈ 20.6:1 Although the above C / N ratio (20.6:1) is slightly lower than the optimal range for aerobic fermentation (25-35:1), the silkworm biochar has a porous structure and adsorption capacity, which can effectively adsorb the ammonia gas produced in the early stage of fermentation and alleviate the ammonia inhibition problem caused by the low C / N ratio. Add an appropriate amount of water to adjust the moisture content to 60%.

[0043] Inoculate the mixture with a compound microbial agent (Bacillus subtilis and thermococcus, mixed in a 1:1 ratio), at a rate of 1% of the total weight of the mixture. Use windrow composting, controlling the pile temperature at 60-65°C, turning the pile every 3 days, and fermenting for 14 days (2 days longer than in Example 6 with an added external carbon source). Fermentation is complete when the pile temperature drops to ambient temperature, the pH stabilizes at 7.0-7.5, there is no odor, and the pile is brownish and loose.

[0044] The fermented and decomposed material is dried at 60℃ to a moisture content of 18%, then crushed and passed through a 100-mesh sieve to obtain the finished bio-organic fertilizer.

[0045] Product testing: Total nitrogen content: 5.5% Small molecule peptides + free amino acids content: 11.2% Chitin + Chitosan Oligosaccharide Content: 1.3% Organic matter content: 56% Effective viable bacteria count: 0.75 billion / g Moisture content: 17% pH value: 7.0 Example 7: Storage Stability Experiment The bio-organic fertilizer obtained in Example 6 was sealed in polyethylene plastic bags and stored for 12 months at room temperature (25±5℃) and relative humidity of 60%. Samples were taken at 0, 3, 6, 9, and 12 months to test indicators such as the number of viable bacteria, chitin content, and germination index.

[0046] Germination Index (GI) determination method: Fermentation product and distilled water were mixed at a ratio of 1:10 (w / v), shaken, and extracted for 1 hour. The extract was then filtered. Twenty cucumber seeds were evenly placed in a petri dish lined with filter paper, and 5 mL of the extract was added. The mixture was incubated in the dark at 25℃ for 48 hours. Germination rate and root length were then measured. Germination Index (GI) = (Treatment germination rate × Treatment root length) / (Control germination rate × Control root length) × 100%.

[0047] The results are as follows: The results showed that after 12 months of storage, the number of effective live bacteria was 0.58 billion / g, which was still higher than the national standard (≥0.2 billion / g), the chitin content remained stable, and the germination index was ≥85%, proving that this product has excellent storage stability.

[0048] Example 8: Mulberry application trial (direct application) A field experiment was conducted in a mulberry orchard in Yunnan Province, with three treatments: Treatment A: Apply the bio-organic fertilizer obtained in Example 6, 2 kg / plant, as a base fertilizer in one application; Treatment B: Apply 2 kg / silkworm excrement organic fertilizer as a base fertilizer in one application. Treatment C: No fertilizer application (control).

[0049] Existing formulas and methods for producing organic fertilizer for sandworms: 1. Raw material preparation: Silkworm excrement: 25-40 parts Mushroom residue: 25-35 parts High-temperature treated chicken manure: 10-15 parts Phosphate fertilizer: 5-10 parts Potassium fertilizer: 5-10 parts. 2. Production steps: Mix the well-rotted and fermented silkworm excrement with the fungal bran evenly and allow it to ferment naturally. After 5 days of fermentation, add phosphate fertilizer and potassium fertilizer and mix evenly.

[0050] After granulation and drying, organic fertilizer can be obtained. 3. Fermentation process: Select silkworm excrement, pre-treat it, add or not add microbial agents for composting and fermentation, and finally dry it. 4. Precautions: During fermentation, ensure the temperature reaches 60-70 degrees Celsius to eliminate pathogens and achieve harmlessness. Mulberry trees (variety Gui Sang You 12) with a 3-year age, a ground diameter (10cm above ground) of 2.5-3.0cm, a crown width of 1.2-1.5m, and uniform growth vigor were selected. Twenty trees were selected for each treatment, arranged in a randomized block design with three replicates, each replicate containing at least five trees. Before bud break in spring, a circular trench 15-20cm deep was dug around the outer edge of the tree crown projection, fertilized, and then covered with soil. Other field management practices (pruning, pest and disease control, etc.) were consistent.

[0051] The yield (fresh weight) of mulberry leaves per plant was calculated after the last leaf harvest in autumn of that year, and the average value of all plants in each treatment was taken. The results are as follows: Note: The data in the table are the average values ​​of each replication, and the differences between treatments are significant (P<0.05).

[0052] Results analysis: Treatment A, which applied the bio-organic fertilizer of this invention, showed the highest yield of single mulberry leaves, increasing by 56.6% compared to the blank control and by 21.3% compared to existing silkworm excrement fertilizer. Crude protein content in mulberry leaves: Treatment A increased by 14.8% compared to treatment B, and by 28.3% compared to the blank control; Incidence of powdery mildew: Treatment A reduced the incidence by 47.4% compared to treatment B, and by 70.5% compared to the control group.

[0053] The product of this invention has excellent effects in increasing yield, improving quality, and resisting disease.

[0054] Example 9: Rice Application Trial (Direct Application) A field trial was conducted in a rice-growing area in Yunnan Province, with three treatments: Treatment A: Apply the bio-organic fertilizer obtained in Example 6 at a rate of 150 kg / mu as a base fertilizer in one application. Treatment B: Apply existing silkworm excrement organic fertilizer (prepared by the method in Example 8) at a rate of 150 kg / mu as a base fertilizer in one application. Treatment C: Conventional fertilization (50 kg / mu of compound fertilizer).

[0055] Each treatment had three replicates, with a plot size of 30 m², arranged in a randomized block design. The rice variety was Yexiangyou 9, and the planting density was 15,000 hills per mu. Fertilizer was applied before transplanting, and other field management practices were consistent.

[0056] The results are as follows: Note: The data in the table are the average values ​​of each replication. The differences between treatment A and treatments B and C are significant (P<0.05).

[0057] Results analysis: Treatment A, which used the bio-organic fertilizer of this invention, showed the highest rice yield, increasing by 7.8% compared to conventional fertilization and by 14.7% compared to commercially available silkworm excrement fertilizer. Crude protein content in rice: Treatment A increased by 9.3% compared to Treatment B, and by 5.1% compared to conventional fertilization.

[0058] Example 10: Sugarcane Application Trial (Second Blending) In view of the high potassium requirement of sugarcane, the bio-organic fertilizer obtained in Example 6B was mixed with potassium sulfate in a ratio of 10:1 (100 kg of bio-organic fertilizer and 10 kg of potassium sulfate) to prepare a high-potassium bio-organic fertilizer.

[0059] A field trial was conducted in a sugarcane-growing area in Yunnan Province, with three treatments: Treatment A: Apply high-potassium bio-organic fertilizer, 200 kg / mu; Treatment B: Apply 200 kg / mu of the unblended bio-organic fertilizer obtained in Example 6B; Treatment C: Conventional fertilization (80 kg / mu of compound fertilizer).

[0060] Each treatment had three replicates, with a plot size of 50 m², arranged in a randomized block design. The sugarcane variety was Guitang 42, and the planting density was 4500 buds / mu. Fertilizer was applied before planting, and other field management practices were consistent.

[0061] The results are as follows: deal with Sugarcane yield (kg / mu) Yield increase rate compared to conventional fertilization (%) Sugar content (%) A (High Potassium Type) 7250 +12.4 14.8 B (Unallocated) 6850 +6.2 13.9 C (Conventional fertilization) 6450 — 13.2 Note: The data in the table are the average values ​​of each replication, and the differences between treatments are significant (P<0.05).

[0062] Results analysis: After two rounds of adjustment, the sugarcane yield increased by 12.4% compared with the conventional fertilization group (treatment A) and by 5.8% compared with the unadjusted group (treatment B). The sugar content was 12.1% higher than that of conventional fertilization and 6.5% higher than that of the unadjusted group.

[0063] Example 12: Peanut Application Experiment (Secondary Blending) In view of the high calcium requirement of peanuts, the bio-organic fertilizer obtained in Example 6 was mixed with oyster shell powder in a ratio of 8:2 (80 kg of bio-organic fertilizer and 20 kg of oyster shell powder) to prepare a high-calcium bio-organic fertilizer.

[0064] A field trial was conducted in a peanut-growing area in Yunnan Province, with three treatments: Treatment A: Apply high-calcium bio-organic fertilizer, 150 kg / mu; Treatment B: Apply the bio-organic fertilizer (unblended) obtained in Example 6 at a rate of 150 kg / mu; Treatment C: Conventional fertilization (50 kg / mu of compound fertilizer).

[0065] Each treatment had three replicates, with a plot size of 30 m², arranged in a randomized block design. The peanut variety was Guihua 22, and the planting density was 12,000 hills per mu. Fertilizer was applied before sowing, and other field management practices were consistent.

[0066] The results are as follows: Note: The data in the table are the average values ​​of each replication, and the differences between treatments are significant (P<0.05).

[0067] Results analysis: After two rounds of adjustment, the peanut yield of the high-calcium bio-organic fertilizer (treatment A) increased by 22.2% compared with the conventional fertilization (treatment C) and by 8.5% compared with the unadjusted group (treatment B). The percentage of full fruit increases, while the percentage of rotten fruit decreases.

[0068] Example 12: Soybean Application Trial (Second Blending) In view of the low nitrogen requirement of legumes, the bio-organic fertilizer obtained in Example 6B was mixed with rice husks in a ratio of 7:3 (70 kg of bio-organic fertilizer and 30 kg of rice husks) to prepare a low-nitrogen bio-organic fertilizer.

[0069] A field trial was conducted in a soybean-growing area in Yunnan Province, with three treatments: Treatment A: Apply low-nitrogen bio-organic fertilizer at a rate of 120 kg / mu; Treatment B: Apply the bio-organic fertilizer (unblended) obtained in Example 6B at a rate of 120 kg / mu; Treatment C: Conventional fertilization (40 kg / mu of compound fertilizer).

[0070] Each treatment had three replicates, with a plot size of 30 m², arranged in a randomized block design. The soybean variety was Guichun 8, and the planting density was 15,000 plants / mu. Fertilizer was applied before sowing, and other field management practices were consistent.

[0071] The results are as follows: Note: The data in the table are the average values ​​of each replication, and the differences between treatments are significant (P<0.05).

[0072] Results analysis: After two rounds of adjustment, the soybean yield under low-nitrogen bio-organic fertilizer (treatment A) increased by 16.7% compared to conventional fertilization (treatment C), and by 8.9% compared to the unadjusted group (treatment B). The number of root nodules increases, and the lodging rate decreases.

[0073] Comparative Example 1: Unmodified Dead silkworms and silkworm moths (unmodified) were mixed with silkworm excrement at a ratio of 30:70, and the C / N ratio was adjusted to 28:1 (rice bran was added for adjustment). The same compound microbial agent was inoculated, and fermentation was carried out according to the method in Example 6. Results showed that ammonia production was high in the early stages of fermentation (ammonia concentration > 50 ppm), and the fermentation period was extended to 18 days. The final product had a total nitrogen content of 4.2%, a small molecule peptide content of 0.5%, and a chitin content of 0.8%. In a mulberry pot experiment (according to the method in Example 8), the yield of mulberry leaves per tree was 10.2 kg / tree, and the incidence of powdery mildew was 18.5%. This indicates that the unmodified silkworm material had poor fermentation performance, low product quality, and weak disease resistance.

[0074] Comparative Example 2: No silkworm charcoal added The modified silkworm carcass material obtained in Example 3 was mixed with silkworm excrement at a ratio of 30:70 (without adding silkworm carcass charcoal), and the C / N ratio was adjusted to 28:1 (by adding rice bran). Fermentation was then carried out according to the method in Example 6. The results showed that the ammonia volatilization loss rate during fermentation was 25% (15% higher than the group with added silkworm carcass charcoal), and the fermentation period was 14 days. The final product had a total nitrogen content of 4.8%. In a mulberry pot experiment (according to the method in Example 8), the yield of mulberry leaves per tree was 12.5 kg / tree, 12.3% lower than treatment A in Example 9. This indicates that the addition of silkworm carcass charcoal can reduce nitrogen loss, promote fermentation, and increase yield.

[0075] Comparative Example 3: Comparison with the prior art (CN112661582A method) Bio-organic fertilizer was prepared according to the method of Example 1 of CN112661582A: 150 parts of modified organic fertilizer base material (organic powder + wood ash + livestock and poultry manure) and 50 parts of modified biochar (tree residue powder + graphene oxide) were prepared according to the same fermentation process.

[0076] A comparative experiment was conducted on mulberry trees in pots with the bio-organic fertilizer obtained in Example 6B (with the same application rate of 2 kg / tree). Mulberry trees of the same age, diameter at root, and crown width were selected, with 10 trees in each treatment and 3 replicates.

[0077] The results are as follows: Note: All differences in the indicators were statistically significant (P<0.05).

[0078] The results showed that the mulberry leaf yield, crude protein content, disease resistance, and soil improvement effect of the product of this invention were significantly better than those of the product prepared by the method of CN112661582A.

[0079] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A bio-organic fertilizer, characterized in that, The raw materials of the bio-organic fertilizer consist of the following components: modified silkworm body material, silkworm body biochar, and silkworm excrement; the modified silkworm body material is prepared from dead silkworms and / or silkworm moths in the first part through preservation and modification treatment, wherein the preservation treatment reduces the moisture content of the dead silkworms and / or silkworm moths to below 30% or the pH value to below 5.5, and the modification treatment partially hydrolyzes the proteins in the dead silkworms and / or silkworm moths into small molecule peptides and free amino acids, and exposes or partially degrades the chitin structure into chitosan oligosaccharides; the silkworm body biochar is prepared from dead silkworms and / or silkworm moths in the second part through carbonization treatment; the weight ratio of the modified silkworm body material, silkworm body biochar, and silkworm excrement is (10~40):(10~40):(50~80).

2. The bio-organic fertilizer according to claim 1, characterized in that, The modification treatment is an enzymatic hydrolysis treatment, and the enzyme used is selected from protease and chitinase; or, the modification treatment is a high temperature and high pressure treatment, with a treatment temperature of 100-130℃, a pressure of 0.1-0.3 MPa, and a treatment time of 30-120 minutes.

3. The bio-organic fertilizer according to claim 1, characterized in that, The carbonization process is carried out under anaerobic or oxygen-limited conditions, with a carbonization temperature of 400-600℃ and a carbonization time of 1-3 hours.

4. A method for preparing a bio-organic fertilizer according to any one of claims 1-3, characterized in that, Includes the following steps: (1) The collected dead silkworms and / or silkworm moths are screened to remove impurities other than the dead silkworms and / or silkworm moths, and divided into a first part and a second part; (2) The first part is subjected to preservation treatment to reduce the moisture content of the dead silkworms and / or silkworm moths to below 30% or the pH value to below 5.5, so as to obtain stable silkworm body material; (3) The stable silkworm body material obtained in step (2) is sterilized at a temperature of 70-90℃ for 24-72 hours; (4) The sterilized silkworm body material obtained in step (3) is modified to partially hydrolyze the proteins in the dead silkworms and / or silkworm moths into small molecule peptides and free amino acids, and expose or partially degrade the chitin structure into chitosan oligosaccharides, so as to obtain modified silkworm body material; (5) The second part is carbonized at a temperature of 400-600℃ for 1-3 hours, cooled and crushed to obtain silkworm biochar; (6) Mix the modified silkworm body material obtained in step (4), the silkworm body biochar obtained in step (5), and silkworm excrement in a weight ratio of (10~40):(10~40):(50~80), adjust the C / N ratio to 25-35:1, and the moisture content to 50%-65%; (7) Inoculate the mixture obtained in step (6) with compound microbial inoculant and carry out aerobic fermentation at a fermentation temperature of 50-70℃ for 7-20 days; (8) Dry, crush, and sieve the fermented and decomposed material to obtain bio-organic fertilizer.

5. The method according to claim 4, characterized in that, The modification treatment in step (4) is an enzymatic hydrolysis treatment, in which the sterilized silkworm material is mixed with protease and chitinase and enzymatically hydrolyzed for 2-8 hours at pH 6.0-8.0 and temperature 45-60℃; or, the modification treatment in step (4) is a high temperature and high pressure treatment, with a treatment temperature of 110-120℃, a pressure of 0.15-0.25MPa, and a treatment time of 45-90 minutes.

6. The method according to claim 4, characterized in that, The compound microbial agent in step (7) contains Bacillus subtilis and thermococcus, and the inoculation amount is 0.5%-2% of the total weight of the mixture.

7. The application of the bio-organic fertilizer according to any one of claims 1-6 in the planting of mulberry trees, rice, rapeseed, corn, wheat, sugarcane, beans, or cash crops, characterized in that, The bio-organic fertilizer can be applied directly or after secondary formulation according to the nutritional needs of different crops. The secondary formulation includes at least one of the following formulation methods: adding potassium fertilizer for crops with high potassium requirements, adding calcium source for crops with high calcium requirements, and adding carbon source regulator for crops with low nitrogen requirements.

8. The application of a bio-organic fertilizer according to claim 7, characterized in that, The potassium fertilizer is selected from at least one of potassium sulfate, potassium chloride, and wood ash, and the amount added is 5%-20% of the total weight of the bio-organic fertilizer; the calcium source is selected from at least one of shell powder, oyster shell powder, gypsum, and lime, and the amount added is 5%-30% of the total weight of the bio-organic fertilizer; the carbon source regulator is selected from at least one of straw powder, rice husk, and biochar, and the amount added is 10%-40% of the total weight of the bio-organic fertilizer.

9. The application of a bio-organic fertilizer according to claim 7, characterized in that, Crops with high potassium requirements include sugarcane, potatoes, tobacco, and bananas; crops with high calcium requirements include peanuts, soybeans, tomatoes, and apples; and crops with low nitrogen requirements include legumes.

10. The application of a bio-organic fertilizer according to claim 7, characterized in that, The secondary formulation also includes: adding an acid regulator for crops that prefer acidic soil, wherein the acid regulator is selected from at least one of sulfur powder and ferrous sulfate, and the amount added is 1%-5% of the total weight of the bio-organic fertilizer; adding an alkaline regulator for crops that prefer alkaline soil, wherein the alkaline regulator is selected from at least one of lime and wood ash, and the amount added is 2%-10% of the total weight of the bio-organic fertilizer.

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