Preparation method of papaya bio-fertilizer additive

Abstract

The application discloses a preparation method of a chaenomeles fruit bio-fertilizer additive, which comprises the following steps: collecting chaenomeles fruit seeds, adding water to the chaenomeles fruit seeds to stir and extract, and concentrating to obtain a concentrated solution containing chaenomeles fruit seed gum, and then crushing the chaenomeles fruit seeds to obtain chaenomeles fruit seed powder; taking chaenomeles fruit residues, crushing the chaenomeles fruit residues, mixing the crushed chaenomeles fruit residues with citric acid, the chaenomeles fruit seed powder and water, filtering, mixing the filtered mixture with water and a compound microbial agent to ferment, and continuously fermenting the mixture to obtain a primary fermentation product; taking the concentrated solution, mixing the concentrated solution with biochar, chitosan and potassium persulfate to react, adding the secondary fermentation product to the mixture to stir and mix to obtain a mixture, and then sending the mixture to a granulator to granulate to obtain the chaenomeles fruit bio-fertilizer additive. The application fully utilizes the waste, such as peels, fermentation residues, rotten fruits and chaenomeles fruit seeds, generated in the processing of chaenomeles fruits to produce the high-quality chaenomeles fruit bio-fertilizer additive, and solves the problem of poor utilization effect of the existing chaenomeles fruit waste.

Description

Technical Field

[0001] This invention belongs to the field of animal feed technology, specifically relating to a method for preparing a papaya bio-fertilizer additive. Background Technology

[0002] Papaya, also known as papaya, longevity fruit, milk melon, and stone melon, belongs to the genus Carica in the family Caricaceae. Its berries are fleshy, turning orange-yellow or yellow when ripe, and are oblong, obovate-oblong, pear-shaped, or nearly spherical in shape. The flesh is soft, juicy, and sweet. The seeds are mostly ovoid and turn black when ripe. Besides being eaten fresh, papaya is rich in nutrients, containing amino acids, vitamins, and trace elements. Its sweet and juicy flesh can also be processed into products such as canned fruit, dried fruit, and preserved fruit. The processing of papayas generates a large amount of waste such as fruit peels and rotten fruit. Although papaya seeds can be pressed for oil, a large amount of water-soluble colloidal byproducts dissolve from the surface of the seeds, increasing the workload and difficulty of pre-treatment before oil extraction. Therefore, the current recycling of these wastes, such as peels and rotten fruit, as well as papaya seeds, is relatively simple. They are mainly mixed with other raw materials for composting to obtain bio-fertilizer. However, this composting method cannot fully recover and utilize the beneficial components in papaya peels and seeds, and the quality and effect of the resulting bio-fertilizer are generally poor. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention discloses a method for preparing a papaya bio-fertilizer additive. This method fully utilizes waste materials generated during papaya processing, such as fruit peels, fermentation residue, rotten fruit, and papaya seeds, to produce a high-quality papaya bio-fertilizer additive, thus solving the problem of poor utilization of existing papaya waste materials.

[0004] This invention is achieved using the following technical solution:

[0005] A method for preparing a papaya bio-fertilizer additive, comprising the following steps:

[0006] (1) Collect papaya seeds and place them in a container. Add water and stir to extract papaya seed gum. The specific process is to place papaya seeds in a container and add water with a weight of 10 times that of papaya seeds. Stir at a temperature of 60-70℃ for 10-15 minutes. Then filter to obtain filtrate A. Repeat the above process 3-4 times. Combine the filtrate A obtained from each process and vacuum concentrate it to one-tenth of the original volume to obtain a concentrated liquid. Then crush the papaya seeds to obtain papaya seed powder.

[0007] (2) Papaya residue is crushed to obtain papaya residue powder. Papaya residue powder, citric acid, papaya seed powder and water are mixed and stirred for 15-30 minutes and then filtered to obtain mixed residue powder. The weight ratio of papaya residue powder, citric acid, papaya seed powder and water is (20-30):(3-5):(1-3):100. The mixed residue powder, water and compound microbial agent are mixed to obtain fermentation material. The weight ratio of mixed residue powder, water and compound microbial agent is (80-100):(20-30):(1-3). The compound microbial agent is obtained by mixing lactic acid bacteria, yeast, Bacillus subtilis and Bacillus licheniformis; the fermentation material is sealed and fermented at 30-35℃ for 5-10 days to obtain a primary fermentation product; the primary fermentation product is mixed evenly with water, peanut meal, and cottonseed meal, and then sealed and fermented at 28-32℃ for 5-10 days to obtain a secondary fermentation product; the weight ratio of the primary fermentation product, water, peanut meal and cottonseed meal is 100:(10-20):(20-30):(20-30);

[0008] (3) Take the concentrated liquid obtained in step (1) and add biochar, chitosan and potassium persulfate in sequence. Mix and stir at 40-50℃ for 1-2 hours to obtain mixture A. Then add the secondary fermentation product obtained in step (2) to mixture A and stir for 15-30 minutes to obtain mixture B. Then send the mixture B to a granulator to granulate to obtain papaya bio-fertilizer additive. The weight ratio of the concentrated liquid, biochar and chitosan is (5-10):(30-40):(3-5):(0.02-0.03), and the weight ratio of mixture B and secondary fermentation product is (3-5):10.

[0009] The papaya residue mentioned above refers to the waste generated during the papaya processing, such as papaya peel, fallen papaya fruit, and rotten fruit.

[0010] Furthermore, the particle size of the papaya seed powder mentioned in step (1) is 100-120 mesh.

[0011] Furthermore, the particle size of the papaya residue powder mentioned in step (2) is 40-80 mesh. Crushing the papaya residue to a suitable particle size can promote the mixing of papaya residue powder with citric acid, papaya seed powder and water, and improve the effect of killing bacteria and insect eggs in the papaya residue powder.

[0012] Furthermore, the compound microbial agent described in step (2) is obtained by mixing the following components in parts by weight: 20-30 parts lactic acid bacteria, 10-15 parts yeast, 5-10 parts Bacillus subtilis, and 5-10 parts Bacillus licheniformis. Adjusting the ratio of different components in the compound microbial agent allows different microbial species to work synergistically, improving the treatment effect of the compound microbial agent.

[0013] Furthermore, in step (3), the concentrated solution obtained in step (1) is sequentially added to biochar, chitosan, and potassium persulfate, and then treated at 40-50°C and a speed of 300-400 r / min for 1-2 hours to obtain mixture A. The stirring speed during the reaction of the concentrated solution, biochar, chitosan, and potassium persulfate is adjusted to promote their interaction and improve the reaction efficiency.

[0014] Further, in step (3), the secondary fermentation product obtained in step (2) is added to mixture A and mixed for 15-30 minutes under stirring conditions of 80-100 r / min to obtain mixture B. The stirring speed of mixing mixture A and the secondary fermentation product is adjusted to promote the coating of the secondary fermentation product with modified biochar to obtain fertilizer granules.

[0015] Further, in step (3), the mixture B is sent to a granulator to granulate fertilizer granules, and papaya seed powder is sprayed onto the fertilizer granules. Then, it is dried at a low temperature of 10-20℃ to obtain papaya bio-fertilizer additive. The weight ratio of the fertilizer granules to the papaya seed powder is 100:(1-3). By fully utilizing the bactericidal and bacteriostatic effects of papaya seed powder, a layer of papaya seed powder is coated on the surface of the fertilizer granules. After the fertilizer is mixed with the soil for fertilization, the papaya seed powder on the surface of the fertilizer can preferentially kill pathogens in the soil, improve the soil environment, and then slowly release the fertilizer to effectively maintain the balance of soil nutrients in the long term.

[0016] Compared with existing technologies, this technical solution has the following advantages:

[0017] 1. This invention uses waste residues generated during papaya processing, such as papaya peels, fallen papaya fruit, and rotten fruit, as raw materials. A compound microbial agent, composed of lactic acid bacteria, yeast, Bacillus subtilis, and Bacillus licheniformis, is added for fermentation to fully utilize the nutrients in the papaya residue to produce a papaya bio-fertilizer additive. Specifically, the papaya residue is crushed and mixed with citric acid, papaya seed powder, and water. The antibacterial components in the citric acid and papaya seeds kill pathogens and insect eggs in the papaya residue powder. The papaya residue powder is then mixed with water and the compound microbial agent for fermentation to obtain a primary fermented product. This primary fermented product is then mixed with water, peanut meal, and cottonseed meal for fermentation to obtain a secondary fermented product. The peanut meal and cottonseed meal are recycled to supplement the fertilizer with organic matter and trace elements, improving fertilizer efficiency. Finally, the secondary fermented product is used as the core layer, which is then coated with a layer of modified biochar. This provides a slow-release effect, effectively maintaining the balance of soil nutrients over a long period.

[0018] 2. This invention uses hot water to treat papaya seeds to obtain a concentrated solution containing papaya seed gum, and then mixes it with biochar, chitosan, and potassium persulfate for cross-linking reaction to obtain modified biochar. Through the cross-linking modification of biochar with papaya seed gum and chitosan in the concentrated solution, the modified biochar has a certain degree of adhesion, which can better form a coating layer to coat the secondary fermentation products, which is beneficial to the granulation of fertilizer granules. At the same time, the modified biochar still has good water absorption, which not only facilitates water penetration and uniform dissolution of nutrients, but also helps to retain soil water and regulate soil moisture. Detailed Implementation

[0019] The present invention is further illustrated by the following examples, but these are not intended to limit the invention. Specific experimental conditions and methods not specified in the following examples are generally conventional methods well known to those skilled in the art.

[0020] Example 1: A method for preparing a papaya bio-fertilizer additive, comprising the following steps:

[0021] (1) Collect papaya seeds and place them in a container and add water to stir and extract papaya seed gum. The specific process is to place papaya seeds in a container and add water with a weight of 10 times that of papaya seeds. Stir and treat at a temperature of 65°C for 12 minutes, then filter to obtain filtrate A. Repeat the above process 3 times. Combine the filtrate A obtained from each process and vacuum concentrate it to one-tenth of the original volume to obtain a concentrated liquid. Then crush the papaya seeds to obtain papaya seed powder. The particle size of the papaya seed powder is 110 mesh.

[0022] (2) Papaya residue is crushed to obtain papaya residue powder. The papaya residue is the waste residue generated during papaya processing, such as papaya peel, fallen papaya fruit, rotten fruit, etc. The particle size of the papaya residue powder is 60 mesh. Papaya residue powder, citric acid, papaya seed powder and water are mixed and stirred for 20 minutes, and then filtered to obtain mixed residue powder. The weight ratio of papaya residue powder, citric acid, papaya seed powder and water is 25:4:2:100. The mixed residue powder, water and compound microbial agent are mixed to obtain fermentation material. The mixed residue powder, water and compound microbial agent... The compound microbial agent, with a weight ratio of 90:25:2, is obtained by mixing the following components in parts by weight: 25 parts lactic acid bacteria, 12 parts yeast, 8 parts Bacillus subtilis, and 8 parts Bacillus licheniformis. The fermentation material is sealed and fermented at 32°C for 8 days to obtain a primary fermentation product. The primary fermentation product is then mixed evenly with water, peanut meal, and cottonseed meal, and sealed and fermented at 30°C for 8 days to obtain a secondary fermentation product. The weight ratio of the primary fermentation product, water, peanut meal, and cottonseed meal is 100:15:25:25.

[0023] (3) Take the concentrated liquid obtained in step (1) and add biochar, chitosan and potassium persulfate in sequence. Mix and treat at 45°C and speed of 350 r / min for 1.5 h to obtain mixture A. Then add the secondary fermentation product obtained in step (2) to mixture A and mix at speed of 90 r / min for 20 min to obtain mixture B. Then send the mixture B to a granulator to granulate to obtain fertilizer granules. Spray the papaya seed powder onto the fertilizer granules and dry at low temperature at 15°C to obtain papaya bio-fertilizer additive. The weight ratio of fertilizer granules to papaya seed powder is 100:2. The weight ratio of concentrated liquid, biochar and chitosan is 6:35:4:0.023. The weight ratio of mixture B and secondary fermentation product is 4:10.

[0024] Example 2: A method for preparing a papaya bio-fertilizer additive, comprising the following steps:

[0025] (1) Collect papaya seeds and place them in a container and add water to stir and extract papaya seed gum. The specific process is to place papaya seeds in a container and add water with a weight of 10 times that of papaya seeds. Stir and treat at a temperature of 60°C for 15 minutes, then filter to obtain filtrate A. Repeat the above process 3 times. Combine the filtrate A obtained from each process and vacuum concentrate it to one-tenth of the original volume to obtain a concentrated liquid. Then crush the papaya seeds to obtain papaya seed powder. The particle size of the papaya seed powder is 100 mesh.

[0026] (2) Papaya residue is crushed to obtain papaya residue powder. The papaya residue is the waste residue generated during papaya processing, such as papaya peel, fallen papaya fruit, rotten fruit, etc. The particle size of the papaya residue powder is 40 mesh. Papaya residue powder, citric acid, papaya seed powder and water are mixed and stirred for 15 minutes and then filtered to obtain mixed residue powder. The weight ratio of papaya residue powder, citric acid, papaya seed powder and water is 20:3:1:100. The mixed residue powder, water and compound microbial agent are mixed to obtain fermentation material. The weight ratio of the mixed residue powder, water and compound microbial agent is 20:3:1:100. The compound microbial agent is prepared by mixing the following components in parts by weight, with a ratio of 80:20:1: 20 parts lactic acid bacteria, 10 parts yeast, 5 parts Bacillus subtilis and 5 parts Bacillus licheniformis. The fermentation material is sealed and fermented at 30°C for 10 days to obtain a primary fermentation product. The primary fermentation product is then mixed evenly with water, peanut meal, and cottonseed meal, and sealed and fermented at 28°C for 10 days to obtain a secondary fermentation product. The weight ratio of the primary fermentation product, water, peanut meal, and cottonseed meal is 100:10:20:20.

[0027] (3) Take the concentrated liquid obtained in step (1) and add biochar, chitosan and potassium persulfate in sequence. Mix and treat at 40°C and speed of 300 r / min for 2 h to obtain mixture A. Then add the secondary fermentation product obtained in step (2) to mixture A and mix at speed of 80 r / min for 15 min to obtain mixture B. Then send the mixture B to a granulator to granulate to obtain fertilizer granules. Spray the papaya seed powder onto the fertilizer granules and dry at low temperature at 10°C to obtain papaya bio-fertilizer additive. The weight ratio of fertilizer granules to papaya seed powder is 100:1. The weight ratio of concentrated liquid, biochar and chitosan is 5:30:3:0.02. The weight ratio of mixture B and secondary fermentation product is 3:10.

[0028] Example 3: A method for preparing a papaya bio-fertilizer additive, comprising the following steps:

[0029] (1) Collect papaya seeds and place them in a container and add water to stir and extract papaya seed gum. The specific process is to place papaya seeds in a container and add water with a weight of 10 times that of papaya seeds. Stir and treat at a temperature of 68°C for 12 minutes, then filter to obtain filtrate A. Repeat the above process 4 times. Combine the filtrate A obtained from each process and vacuum concentrate it to one-tenth of the original volume to obtain a concentrated liquid. Then crush the papaya seeds to obtain papaya seed powder. The particle size of the papaya seed powder is 120 mesh.

[0030] (2) Papaya residue is crushed to obtain papaya residue powder. The papaya residue is the waste generated during papaya processing, such as papaya peel, fallen papaya fruit, rotten fruit, etc. The particle size of the papaya residue powder is 50 mesh. Papaya residue powder, citric acid, papaya seed powder and water are mixed and stirred for 25 minutes and then filtered to obtain mixed residue powder. The weight ratio of papaya residue powder, citric acid, papaya seed powder and water is 28:4.2:1.5:100. The mixed residue powder, water and compound microbial agent are mixed to obtain fermentation material. The mixed residue powder, water and compound microbial agent are mixed to obtain fermentation material. The weight ratio of the agents is 85:25:2. The compound microbial agent is obtained by mixing the following components in parts by weight: 22 parts lactic acid bacteria, 12 parts yeast, 6 parts Bacillus subtilis and 8 parts Bacillus licheniformis. The fermentation material is sealed and fermented at 32°C for 6 days to obtain a primary fermentation product. The primary fermentation product is mixed evenly with water, peanut meal, and cottonseed meal, and then sealed and fermented at 30°C for 8 days to obtain a secondary fermentation product. The weight ratio of the primary fermentation product, water, peanut meal, and cottonseed meal is 100:12:28:25.

[0031] (3) Take the concentrated liquid obtained in step (1) and add biochar, chitosan and potassium persulfate in sequence. Mix and treat at 48°C and speed of 350 r / min for 1.5 h to obtain mixture A. Then add the secondary fermentation product obtained in step (2) to mixture A and mix at speed of 90 r / min for 25 min to obtain mixture B. Then send the mixture B to a granulator to granulate to obtain fertilizer granules. Spray the papaya seed powder onto the fertilizer granules and dry at low temperature at 15°C to obtain papaya bio-fertilizer additive. The weight ratio of fertilizer granules to papaya seed powder is 100:1.5. The weight ratio of concentrated liquid, biochar and chitosan is 6:32:4:0.025. The weight ratio of mixture B and secondary fermentation product is 4:10.

[0032] Example 4: A method for preparing a papaya bio-fertilizer additive, comprising the following steps:

[0033] (1) Collect papaya seeds and place them in a container and add water to stir and extract papaya seed gum. The specific process is to place papaya seeds in a container and add water with a weight of 10 times that of papaya seeds. Stir and process at a temperature of 70°C for 10 minutes, then filter to obtain filtrate A. Repeat the above process 4 times. Combine the filtrate A obtained from each process and vacuum concentrate it to one-tenth of the original volume to obtain a concentrated liquid. Then crush the papaya seeds to obtain papaya seed powder. The particle size of the papaya seed powder is 120 mesh.

[0034] (2) Papaya residue is crushed to obtain papaya residue powder. The papaya residue is the waste residue generated during papaya processing, such as papaya peel, fallen papaya fruit, rotten fruit, etc. The particle size of the papaya residue powder is 80 mesh. Papaya residue powder, citric acid, papaya seed powder and water are mixed and stirred for 30 minutes and then filtered to obtain mixed residue powder. The weight ratio of papaya residue powder, citric acid, papaya seed powder and water is 30:5:3:100. The mixed residue powder, water and compound microbial agent are mixed to obtain fermentation material. The weight ratio of the mixed residue powder, water and compound microbial agent is 30:5:3:100. The ratio is 100:30:3. The compound microbial agent is obtained by mixing the following components in parts by weight: 30 parts lactic acid bacteria, 15 parts yeast, 10 parts Bacillus subtilis and 10 parts Bacillus licheniformis. The fermentation material is sealed and fermented at 35°C for 5 days to obtain a primary fermentation product. The primary fermentation product is mixed evenly with water, peanut meal, and cottonseed meal, and then sealed and fermented at 32°C for 5 days to obtain a secondary fermentation product. The weight ratio of the primary fermentation product, water, peanut meal, and cottonseed meal is 100:20:30:30.

[0035] (3) Take the concentrated liquid obtained in step (1) and add biochar, chitosan and potassium persulfate in sequence. Mix and treat at 50°C and speed of 400 r / min for 1 h to obtain mixture A. Then add the secondary fermentation product obtained in step (2) to mixture A and mix at speed of 100 r / min for 30 min to obtain mixture B. Then send the mixture B to a granulator to granulate to obtain fertilizer granules. Spray the papaya seed powder onto the fertilizer granules and dry at low temperature at 20°C to obtain papaya bio-fertilizer additive. The weight ratio of fertilizer granules to papaya seed powder is 100:3. The weight ratio of concentrated liquid, biochar and chitosan is 10:40:5:0.03. The weight ratio of mixture B and secondary fermentation product is 5:10.

[0036] Comparative Example 1: The preparation method of the papaya bio-fertilizer additive described in this comparative example differs from the method described in Example 1 only in that, in step (2), the papaya residue powder and water are mixed and stirred for 15 to 30 minutes and then filtered to obtain mixed residue powder.

[0037] Comparative Example 2: The preparation method of the papaya bio-fertilizer additive described in this comparative example differs from the method described in Example 1 only in that, in step (2), the papaya residue powder, citric acid and water are mixed and stirred for 15 to 30 minutes and then filtered to obtain mixed residue powder.

[0038] Comparative Example 3: The method for preparing the papaya bio-fertilizer additive described in this comparative example differs from the method described in Example 1 only in that water is used in step (3) instead of the concentrated solution obtained in step (1) to react with biochar, chitosan and potassium persulfate.

[0039] Comparative Example 4: The preparation method of the papaya bio-fertilizer additive described in this comparative example differs from the method described in Example 1 only in that, in step (3), the mixture B is sent to a granulator to granulate and obtain fertilizer granules. Instead of spraying papaya seed powder onto the fertilizer granules, the obtained fertilizer granules are directly dried at a low temperature of 15°C to obtain the papaya bio-fertilizer additive.

[0040] Experimental Example 1: Papaya bio-fertilizer additive was prepared according to the method described in Example 1, wherein the compound microbial agent was prepared according to the ratio in Table 1; the obtained papaya bio-fertilizer additive was mixed evenly with compound fertilizer (15-15-15) to obtain a mixed fertilizer, wherein the weight ratio of papaya bio-fertilizer additive to compound fertilizer (15-15-15) was 1:100; then the obtained mixed fertilizer was used to conduct a pot experiment on dwarf tomatoes. Specifically, dwarf tomato seedlings were transplanted into pots and divided into 7 groups. Six groups were given mixed fertilizer prepared by mixing papaya bio-fertilizer additive with compound fertilizer (15-15-15), and the other group served as a control group and was given the same amount of compound fertilizer (15-15-15). Fertilizer was applied every 15 days after seedling transplanting, with 10g of fertilizer applied to each plant each time. The weight of the single fruit and the plant height of the dwarf tomatoes were counted. The specific results are shown in Table 1.

[0041] Table 1. Proportioning Table of Compound Microbial Agents

[0042]

[0043] Experimental Example 2: Papaya bio-fertilizer additives were prepared according to the methods described in Examples 1-4 and Comparative Examples 1-4. These additives were then mixed with compound fertilizer (15-15-15) at a weight ratio of 1:100. A field experiment was then conducted on 1000 mu of papaya planted in 9 regions over a planting period of 8 months. Eight regions received a mixture of the papaya bio-fertilizer additives prepared according to the methods described in Examples 1-4 and Comparative Examples 1-4 and compound fertilizer (15-15-15). The remaining region served as a control group, receiving only the same amount of compound fertilizer (15-15-15). All regions underwent the same field management practices. The yield of papaya and the incidence rates of mosaic virus and anthracnose were statistically analyzed. Specific results are shown in Table 2.

[0044] Table 2. Results of papaya cultivation using different fertilizers

[0045]

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a papaya bio-fertilizer additive, characterized in that: Includes the following steps: (1) Collect papaya seeds and place them in a container. Add water and stir to extract papaya seed gum. The specific process is to place papaya seeds in a container and add water with a weight of 10 times that of papaya seeds. Stir at a temperature of 60-70℃ for 10-15 minutes. Then filter to obtain filtrate A. Repeat the above process 3-4 times. Combine the filtrate A obtained from each process and vacuum concentrate it to one-tenth of the original volume to obtain a concentrated liquid. Then crush the papaya seeds to obtain papaya seed powder. (2) Papaya residue is crushed to obtain papaya residue powder. Papaya residue powder, citric acid, papaya seed powder and water are mixed and stirred for 15-30 minutes and then filtered to obtain mixed residue powder. The weight ratio of papaya residue powder, citric acid, papaya seed powder and water is (20-30):(3-5):(1-3):

100. Mix the mixed residue powder, water and compound microbial agent to obtain fermentation material. The weight ratio of mixed residue powder, water and compound microbial agent is (80-100):(20-30):(1-3). The compound microbial agent is obtained by mixing lactic acid bacteria, yeast, Bacillus subtilis and Bacillus licheniformis. The fermentation material is sealed and fermented at 30-35℃ for 5-10 days to obtain a primary fermentation product. The primary fermentation product is then mixed evenly with water, peanut meal, and cottonseed meal, and sealed and fermented at 28-32℃ for 5-10 days to obtain a secondary fermentation product. The weight ratio of the primary fermentation product, water, peanut meal, and cottonseed meal is 100:(10-20):(20-30):(20-30). The compound microbial agent is obtained by mixing the following components in parts by weight: 20-30 parts lactic acid bacteria, 10-15 parts yeast, 5-10 parts Bacillus subtilis, and 5-10 parts Bacillus licheniformis. (3) Take the concentrated liquid obtained in step (1) and add biochar, chitosan and potassium persulfate in sequence. Mix and treat at 40-50℃ and speed of 300-400r / min for 1-2h to obtain mixture A. Then add the secondary fermentation product obtained in step (2) to mixture A and mix at a speed of 80-100r / min for 15-30min to obtain mixture B. Send mixture B to a granulator to granulate to obtain fertilizer granules. Spray papaya seed powder onto the fertilizer granules and dry at low temperature of 10-20℃ to obtain papaya bio-fertilizer additive. The weight ratio of fertilizer granules to papaya seed powder is 100:(1-3). The weight ratio of concentrated liquid, biochar, chitosan and potassium persulfate is (5-10):(30-40):(3-5):(0.02-0.03). The weight ratio of mixture A and secondary fermentation product is (3-5):

10.

2. The method for preparing the papaya bio-fertilizer additive according to claim 1, characterized in that: The particle size of the papaya seed powder mentioned in step (1) is 100-120 mesh.

3. The method for preparing the papaya bio-fertilizer additive according to claim 1, characterized in that: The particle size of the papaya residue powder mentioned in step (2) is 40-80 mesh.

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