Livestock and poultry manure and straw fermentation bio-organic fertilizer and preparation method thereof

Abstract

This invention relates to the field of bio-organic fertilizer technology, and discloses a bio-organic fertilizer made from fermented livestock and poultry manure and straw, and its preparation method. The method includes the following raw materials in parts by weight: inoculating a compound microbial strain into a seed culture medium for inoculation and cultivation to obtain a fermentation broth; mixing livestock and poultry manure and straw to form compost material, adding the fermentation broth to the compost material, and fermenting and composting to obtain manure fermentation products; drying and pulverizing the manure fermentation products, then mixing them with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and a composite carrier, stirring, granulating, and drying to obtain bio-organic fertilizer. The bio-organic fertilizer prepared by inoculating a compound microbial strain into a seed culture medium to obtain a fermentation broth, adding the fermentation broth to livestock and poultry manure and straw, fermenting and composting, and then mixing it with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and a composite carrier has high fertility and can reduce the loss of nutrients such as nitrogen, phosphorus, and potassium in organic fertilizer, thereby improving the fertility of organic fertilizer.

Description

Technical Field

[0001] This invention relates to the field of bio-organic fertilizer production technology, specifically to a bio-organic fertilizer made from fermented livestock and poultry manure and straw, and its preparation method. Background Technology

[0002] Bio-organic fertilizer is a type of fertilizer composed of specific functional microorganisms and harmlessly treated and decomposed animal and plant residues (such as livestock and poultry manure, crop straw, etc.). It combines the effects of microbial fertilizer and organic fertilizer. Its raw materials include agricultural waste, industrial waste and urban sludge. By adding functional microbial groups such as nitrogen-fixing bacteria and phosphorus-solubilizing bacteria, it can improve soil structure, release nutrients and inhibit pathogens. Moreover, bio-organic fertilizer has complete nutrients, which can improve soil, improve product quality, improve the rhizosphere microbiome of crops and enhance the plant's resistance to diseases and pests.

[0003] However, bio-organic fertilizers suffer from significant loss of nutrients such as nitrogen, phosphorus, and potassium, and have low activity, resulting in low utilization rates. Furthermore, ammonium nitrogen in bio-organic fertilizers hydrolyzes into ammonium carbonate, causing ammonium nitrogen to exist in the compound fertilizer in a positively charged form for a longer period, leading to nitrogen loss. By mixing nitrification inhibitors with bio-organic fertilizers, nitrifying bacteria can be inhibited, reducing nitrogen loss. However, these inhibitors are volatile or sensitive to light and heat, and on-site mixing and exposure to the environment can easily cause the active ingredients to volatilize or decompose. Summary of the Invention

[0004] This invention provides a fermented bio-organic fertilizer made from livestock and poultry manure and straw, and its preparation method, which solves the problems of easy loss of beneficial components in bio-organic fertilizer and easy decomposition and failure of nitrification inhibitors under high temperature granulation.

[0005] The technical solution of the present invention: S1. Inoculate the compound microbial strain into the seed culture medium and carry out inoculation culture to obtain fermentation broth; S2. Mix livestock and poultry manure and straw to form compost material, add fermentation liquid to the compost material, and carry out fermentation composting to obtain manure fermentation products. S3. After drying and crushing, the fermented manure products are mixed with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer and composite carrier. The mixture is stirred at 60-100 rpm for 5-10 minutes, granulated and dried to obtain bio-organic fertilizer. The composite carrier is obtained by surface modification of polydopamine with nitration inhibitors, followed by reaction with modified cellulose nanofibers, tannic acid, and zinc chloride. The modified cellulose nanofibers are obtained by synthesizing iron-copper nanocomposite materials on the surface of functionalized cellulose nanofibers.

[0006] Furthermore, the composite carrier is prepared by the following steps: A1. Add cellulose nanofibers and tannic acid to deionized water, stir and react at 60-70℃ for 20-30 min, filter, wash and dry to obtain functionalized cellulose nanofibers. A2. Mix peanut vines and deionized water evenly, heat at 95-105℃ for 1-2 hours, centrifuge to obtain peanut vine extract, mix peanut vine extract with ferric chloride solution and copper chloride solution evenly, add functionalized cellulose nanofibers, stir and react, collect precipitate by centrifugation, wash precipitate, dry to obtain modified cellulose nanofibers. A3. Add the nitration inhibitor particles to Tris-HCl buffer, stir until homogeneous, add dopamine, stir and react, then filter, wash and dry to obtain polydopamine-modified nitration inhibitor. A4. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred until homogeneous. Zinc chloride and polydopamine-modified nitration inhibitors were added and stirred to react. The gel was collected by filtration and then freeze-dried to obtain the composite carrier.

[0007] Furthermore, during the A1 reaction described above, under alkaline conditions, citric acid contains a large number of oxygen-containing functional groups that can chemically bond with the hydroxyl groups on the surface of cellulose nanofibers, thereby coating the surface of cellulose nanofibers with citric acid and obtaining functionalized cellulose nanofibers.

[0008] Furthermore, during the A2 reaction process described above, the oxygen-containing functional groups on the surface of the functionalized cellulose nanofibers can electrostatically combine with the iron and copper ions in ferric chloride and copper chloride, causing the iron and copper ions to deposit on the surface of the cellulose nanofibers. In addition, the polyphenolic compounds and flavonoids contained in the peanut vine extract act as reaction promoters, which can react with the iron and copper ions to form a porous iron-copper nanocomposite material in the form of iron oxide and copper oxide, which is deposited on the surface of the cellulose nanofibers to obtain modified cellulose nanofibers.

[0009] Furthermore, in the A3 reaction process described above, a spray dryer is used to spray the mixture of dopamine and Tris-HCl buffer onto the surface of the nitration inhibitor particles. This can prevent the additive complex from sticking together, and dopamine can undergo a self-polymerization reaction on the surface of the nitration inhibitor particles to form a polydopamine film that coats the surface of the nitration inhibitor particles, thus obtaining a polydopamine-modified nitration inhibitor.

[0010] Furthermore, in the A4 reaction process described above, the modified cellulose nanofibers serve as the gel skeleton, and tannic acid can undergo a cross-linking reaction with the modified cellulose nanofibers. In addition, zinc ions in zinc chloride and polydopamine-modified nitration inhibitors can participate in the cross-linking reaction, increasing the cross-linking density of the gel. This allows the polydopamine-modified nitration inhibitors to be embedded in the porous gel system, resulting in a composite carrier.

[0011] Further, in step A1, the mass ratio of the cellulose nanofibers and tannic acid added to the deionized water is (2-3):(0.5-1):(100-120).

[0012] Further, in step A2, the mass ratio of peanut vines to deionized water is (4-6):(70-80).

[0013] Further, in step A2, the mass ratio of the peanut vine extract, ferric chloride solution, copper chloride solution and functionalized cellulose nanofibers is (30-40):(10-15):(12-16):(4-5).

[0014] Further, in step A3, the mass ratio of dopamine to Tris-HCl buffer is (0.1-0.2):(60-70).

[0015] Further, in step A3, the mass ratio of the nitrification inhibitor particles to the mixture is 1:(0.3-0.5).

[0016] Furthermore, in step A3, the spraying is performed using a spray dryer with a spray pressure of 0.3-0.5 MPa and an inlet air temperature of 40-50°C; the oscillation rate is 80-150 r / min and the oscillation time is 10-15 min.

[0017] Further, in step A4, the mass ratio of the modified cellulose nanofibers, tannic acid, deionized water, zinc chloride, and polydopamine-modified nitration inhibitor is (2-3):(0.4-0.6):(80-100):(0.1-0.3):(1.5-2).

[0018] Further, in step S1, the composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus licheniformis and Bacillus megaterium in a live bacterial count ratio of 1:1:(1-3).

[0019] Further, in step S1, the culture medium formula is as follows: glucose 15-20 g / L, corn starch 10-15 g / L, peptone 5-10 g / L, yeast powder 5-10 g / L, amino acids 8-10 g / L, magnesium sulfate 0.4-0.5 g / L, potassium dihydrogen phosphate 0.4-0.5 g / L, and the pH value of the culture medium is 7.0-7.2.

[0020] Further, in step S1, the inoculation culture specifically involves: an inoculation amount of 3-5%, and culture at 30-32℃ and 180-200rpm for 20-24 hours.

[0021] Furthermore, in step S2, the mass ratio of livestock and poultry manure to straw is (4-5):1, and the moisture content of the compost material is 50-65%.

[0022] Furthermore, in step S2, the ratio of the compost material to the fermentation liquid is 100:(3-5).

[0023] Further, in step S2, the fermentation and composting are specifically carried out as follows: first, at a temperature of 20-25℃, the pile is turned over 1-2 times every 8 hours; second, at a temperature of 50-70℃, the pile is turned over 1-2 times every 2 days; finally, at a temperature of 20-50℃, the pile is turned over 1-2 times every 5 days, and the composting is ended when the temperature drops to 20-25℃.

[0024] Further, in step S3, the mass ratio of the manure fermentation product, urea, monoammonium phosphate, potassium dihydrogen sulfate, calcium magnesium phosphate fertilizer and composite carrier is (8-10):(15-20):(8-10):(8-10):(3-5):(10-15).

[0025] The present invention has the following beneficial effects: (1) In the technical solution of the present invention, citric acid is coated on the surface of cellulose nanofibers to improve the surface activity of cellulose nanofibers, which is conducive to the synthesis of iron-copper nanocomposite materials with porous structure on the surface of cellulose nanofibers, enhancing the adsorption of nutrients in fertilizers, reducing the loss of fertilizer nutrients, and cellulose nanofibers have excellent aspect ratio, which can adsorb more nutrients, further enhancing the fertility of bio-organic fertilizer.

[0026] (2) In the technical solution of the present invention, iron-copper nanocomposite material with porous structure is synthesized on the surface of cellulose nanofiber. On the one hand, the synthesized iron-copper nanocomposite material has a rich porous structure, which can have good heat insulation performance, prevent heat from penetrating into the composite carrier, avoid high temperature granulation which can easily lead to the decomposition and failure of nitrification inhibitor, and the iron and copper elements in the iron-copper nanocomposite material can increase the fertility of the composite bio-fertilizer. On the other hand, cellulose nanofiber, as the carrier of iron-copper nanocomposite material, can load more iron-copper nanocomposite material, and can prevent the iron-copper nanocomposite material from agglomerating, thereby improving the fertility of bio-organic fertilizer. In addition, the porous structure of iron-copper nanocomposite material has high adsorption performance, which can adsorb nutrients in fertilizer, reduce the loss of nutrients in fertilizer, and improve the fertility of bio-organic fertilizer.

[0027] (3) In the technical solution of the present invention, the polydopamine membrane is coated on the surface of the nitrification inhibitor particles, which is conducive to the uniform dispersion of the nitrification inhibitor in the composite carrier, avoiding the easy decomposition and failure of the nitrification inhibitor under high temperature granulation, which affects the fertility of the fertilizer. Moreover, the nitrification inhibitor can inhibit nitrifying bacteria, delay the hydrolysis of ammonium nitrogen in the compound fertilizer into ammonium carbonate, and allow ammonium nitrogen to exist in the compound fertilizer in a positive charge form for a longer time, thereby reducing the loss of nitrogen fertilizer. The aerogel prepared by mixing modified cellulose nanofibers, tannic acid, zinc chloride, and polydopamine-modified nitrification inhibitor is used as the composite carrier. On the one hand, the formed aerogel has a porous structure and has a high adsorption of nutrients in the fertilizer, further reducing the loss of nutrients in the fertilizer. On the other hand, the polydopamine-modified nitrification inhibitor increases the crosslinking density of the aerogel, enhances the mechanical properties of the composite carrier, and prevents the pores of the composite carrier from collapsing during the granulation process, losing the adsorption of nutrients in the compound fertilizer, which would lead to a decrease in the fertility of the compound fertilizer. In addition, the zinc ions in the composite carrier can also improve the fertility of the compound fertilizer.

[0028] (4) In the technical solution of the present invention, the nitrification inhibitor is coated in a composite carrier, and then the manure fermentation product, urea, monoammonium phosphate, potassium dihydrogen sulfate and calcium magnesium phosphate are mixed and granulated, so that the nitrification inhibitor can be evenly dispersed in the organic fertilizer, ensuring that the nitrification can be delayed in each nitrogen fertilizer area in the soil, thereby achieving the consistency of the yield of the whole field, avoiding insufficient mixing on site, which may lead to excessively high or low concentrations of inhibitor in some areas. In addition, the nitrification inhibitor is volatile or sensitive to light and heat. On site mixing and exposure to the environment can easily cause the active ingredients to volatilize or decompose. Coating the nitrification inhibitor in a composite carrier can solve this problem. Furthermore, in the process of producing organic fertilizer, the nitrification inhibitor is mixed into the organic fertilizer. When using it, it can be applied by spreading or machine application like ordinary fertilizer, eliminating the secondary mixing process and significantly improving the fertilization efficiency.

[0029] (5) In the technical solution of the present invention, the compound strain is inoculated into the seed culture medium to obtain fermentation liquid. The fermentation liquid is added to livestock and poultry manure and straw, and after fermentation and composting, it is mixed with urea, monoammonium phosphate, potassium dihydrogen sulfate, calcium magnesium phosphate fertilizer and compound carrier to prepare bio-organic fertilizer with high fertility. It can also reduce the loss of nutrients such as nitrogen, phosphorus and potassium in organic fertilizer and improve the fertility of organic fertilizer. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] The raw materials used in the embodiments of this invention are shown below, and all reagents used are analytical grade.

[0032] Among them, Bacillus subtilis (ACCC 60429), Bacillus licheniformis (ATCC 14580), and Bacillus megaterium (CICC 20665) were purchased from the China Industrial Microbial Culture Collection Center.

[0033] The calcium magnesium phosphate fertilizer was purchased from Jinan Hengyuan Chemical Co., Ltd.

[0034] The nitration inhibitor particles are 2-chloro-6-(trichloromethyl)pyridine (also known as nitridine) particles.

[0035] The cellulose nanofibers have a diameter of 50 nm and a length of 5 μm.

[0036] The compound bacterial strain was obtained by mixing Bacillus subtilis, Bacillus licheniformis and Bacillus megaterium in a live bacterial count ratio of 1:1:2.

[0037] The culture medium formula is as follows: glucose 18g / L, corn starch 13g / L, peptone 8g / L, yeast extract 8g / L, amino acids 9g / L, magnesium sulfate 0.45g / L, potassium dihydrogen phosphate 0.45g / L, and the pH value of the culture medium is 7.1.

[0038] Example 1 A method for preparing fermented bio-organic fertilizer from livestock and poultry manure and straw includes the following preparation steps: S1. Inoculate the compound microbial strain into the seed culture medium and carry out inoculation culture to obtain fermentation broth; wherein, the inoculation culture is specifically as follows: the inoculation amount is 3%, and the culture is carried out at 30℃ and 180rpm for 20h; S2. Mix livestock and poultry manure and straw to form compost material, add fermentation liquid to the compost material, and carry out fermentation composting to obtain manure fermentation products; wherein, the mass ratio of livestock and poultry manure to straw is 4:1, the moisture content of the compost material is 50%, and the ratio of compost material to fermentation liquid is 100:3; the specific fermentation composting process is as follows: first, at a temperature of 20℃, turn the pile once every 8 hours; second, at a temperature of 50℃, turn the pile once every 2 days; finally, at a temperature of 20℃, turn the pile once every 5 days, and when the temperature drops to 20℃, the composting is stopped; S3. After drying and pulverizing, the manure fermentation product is mixed with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and composite carrier. The mixture is stirred at 60 rpm for 5 minutes, granulated, and dried to obtain bio-organic fertilizer. The mass ratio of manure fermentation product, urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and composite carrier is 8:15:8:8:3:10.

[0039] The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 60°C for 20 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 2:0.5:100. A2. Mix peanut vines and deionized water evenly, heat at 95℃ for 1 hour, and centrifuge at 4200 r / min for 30 minutes to obtain peanut vine extract. The mass ratio of peanut vines to deionized water is 4:70. Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Functionalized cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 3 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and functionalized cellulose nanofibers was 30:10:12:4. A3. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.1:60; the mass ratio of nitration inhibitor particles to the mixture is 1:0.3; spraying is performed using a spray dryer with a spray pressure of 0.3 MPa and an inlet air temperature of 40°C; the shaking rate is 80 r / min and the shaking time is 10 min. A4. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred evenly. Zinc chloride and polydopamine-modified nitration inhibitor were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, tannic acid, deionized water, zinc chloride and polydopamine-modified nitration inhibitor was 2:0.4:80:0.1:1.5.

[0040] Example 2 A method for preparing fermented bio-organic fertilizer from livestock and poultry manure and straw includes the following preparation steps: S1. Inoculate the compound microbial strain into the seed culture medium and carry out inoculation culture to obtain fermentation broth; wherein, the inoculation culture is specifically as follows: the inoculation amount is 4%, and the culture is carried out at 31℃ and 190rpm for 22h; S2. Mix livestock and poultry manure and straw to form compost material, add fermentation liquid to the compost material, and carry out fermentation composting to obtain manure fermentation products; wherein, the mass ratio of livestock and poultry manure to straw is (4-5):1, the moisture content of the compost material is 60%, and the ratio of compost material to fermentation liquid is 100:4; the specific fermentation composting process is as follows: first, at a temperature of 23℃, turn the pile once every 8 hours; second, at a temperature of 60℃, turn the pile once every 2 days; finally, at a temperature of 30℃, turn the pile once every 5 days, and when the temperature drops to 23℃, the composting is stopped; S3. After drying and pulverizing, the manure fermentation products are mixed with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and composite carrier. The mixture is stirred at 80 rpm for 8 minutes, granulated, and dried to obtain bio-organic fertilizer. The mass ratio of manure fermentation products, urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and composite carrier is 9:18:9:9:4:13.

[0041] The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 65°C for 25 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 2.5:0.7:110. A2. Mix peanut vines and deionized water evenly, heat at 100℃ for 1.5h, centrifuge at 4200r / min for 30min to obtain peanut vine extract, with a peanut vine to deionized water mass ratio of 5:75; Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Functionalized cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 3 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and functionalized cellulose nanofibers was 35:13:14:4.5. A3. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.15:65; the mass ratio of nitration inhibitor particles to the mixture is 1:0.4; spraying is performed using a spray dryer with a spray pressure of 0.4 MPa and an inlet air temperature of 45°C; the shaking rate is 100 r / min and the shaking time is 13 min. A4. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred until homogeneous. Zinc chloride and polydopamine-modified nitration inhibitor were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, tannic acid, deionized water, zinc chloride, and polydopamine-modified nitration inhibitor was 2.5:0.5:90:0.2:1.8.

[0042] Example 3 A method for preparing fermented bio-organic fertilizer from livestock and poultry manure and straw includes the following preparation steps: S1. Inoculate the compound microbial strain into the seed culture medium and carry out inoculation culture to obtain fermentation broth; wherein, the inoculation culture is specifically as follows: the inoculation amount is 5%, and the culture is carried out at 32℃ and 200rpm for 24h; S2. Mix livestock and poultry manure and straw to form compost material, add fermentation liquid to the compost material, and carry out fermentation composting to obtain manure fermentation products; wherein, the mass ratio of livestock and poultry manure to straw is (4-5):1, the moisture content of the compost material is 65%; the ratio of compost material to fermentation liquid is 100:5; the specific fermentation composting process is as follows: first, at a temperature of 25℃, turn the pile 1-2 times every 8 hours; second, at a temperature of 70℃, turn the pile twice every 2 days; finally, at a temperature of 50℃, turn the pile twice every 5 days, and when the temperature drops to 25℃, the composting is stopped; S3. After drying and pulverizing, the manure fermentation product is mixed with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and composite carrier. The mixture is stirred at 100 rpm for 10 minutes, granulated, and dried to obtain bio-organic fertilizer. The mass ratio of manure fermentation product, urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer, and composite carrier is 10:20:10:10:5:15.

[0043] The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 70°C for 30 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 3:1:120. A2. Mix peanut vines and deionized water evenly, heat at 105℃ for 2 hours, and centrifuge at 4200 r / min for 30 minutes to obtain peanut vine extract. The mass ratio of peanut vines to deionized water is 6:80. Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Functionalized cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 2-4 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and functionalized cellulose nanofibers was 40:15:16:5. A3. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.2:70; the mass ratio of nitration inhibitor particles to the mixture is 1:0.5; spraying is performed using a spray dryer with a spray pressure of 0.5 MPa and an inlet air temperature of 50°C; the shaking rate is 150 r / min and the shaking time is 15 min. A4. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred until homogeneous. Zinc chloride and polydopamine-modified nitration inhibitor were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, tannic acid, deionized water, zinc chloride, and polydopamine-modified nitration inhibitor was 3:0.6:100:0.3:2.

[0044] Comparative Example 1 The only difference between this comparative example and Example 3 is the preparation of the composite carrier, as detailed below: The composite carrier is prepared by the following steps: A1. Mix peanut vines and deionized water evenly, heat at 105℃ for 2 hours, and centrifuge at 4200 r / min for 30 minutes to obtain peanut vine extract. The mass ratio of peanut vines to deionized water is 6:80. Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 2-4 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and cellulose nanofibers was 40:15:16:5. A2. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.2:70; the mass ratio of nitration inhibitor particles to the mixture is 1:0.5; spraying is performed using a spray dryer with a spray pressure of 0.5 MPa and an inlet air temperature of 50°C; the shaking rate is 150 r / min and the shaking time is 15 min. A3. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred evenly. Zinc chloride and polydopamine-modified nitration inhibitor were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, tannic acid, deionized water, zinc chloride and polydopamine-modified nitration inhibitor was 3:0.6:100:0.3:2.

[0045] Comparative Example 2 The only difference between this comparative example and Example 3 is the preparation of the composite carrier, as detailed below: The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 70°C for 30 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 3:1:120. A2. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.2:70; the mass ratio of nitration inhibitor particles to the mixture is 1:0.5; spraying is performed using a spray dryer with a spray pressure of 0.5 MPa and an inlet air temperature of 50°C; the shaking rate is 150 r / min and the shaking time is 15 min. A3. Functionalized cellulose nanofibers and tannic acid were added to deionized water and stirred until homogeneous. Zinc chloride and polydopamine-modified nitration inhibitor were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of functionalized cellulose nanofibers, tannic acid, deionized water, zinc chloride, and polydopamine-modified nitration inhibitor was 3:0.6:100:0.3:2.

[0046] Comparative Example 3 The only difference between this comparative example and Example 3 is the preparation of the composite carrier, as detailed below: The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 70°C for 30 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 3:1:120. A2. Mix peanut vines and deionized water evenly, heat at 105℃ for 2 hours, and centrifuge at 4200 r / min for 30 minutes to obtain peanut vine extract. The mass ratio of peanut vines to deionized water is 6:80. Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Functionalized cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 2-4 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and functionalized cellulose nanofibers was 40:15:16:5. A3. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred evenly. Zinc chloride and nitration inhibitor particles were added and stirred at 25℃ and 120r / min for 3h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, tannic acid, deionized water, zinc chloride and nitration inhibitor particles was 3:0.6:100:0.3:2.

[0047] Comparative Example 4 The only difference between this comparative example and Example 3 is the preparation of the composite carrier, as detailed below: The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 70°C for 30 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 3:1:120. A2. Mix peanut vines and deionized water evenly, heat at 105℃ for 2 hours, and centrifuge at 4200 r / min for 30 minutes to obtain peanut vine extract. The mass ratio of peanut vines to deionized water is 6:80. Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Functionalized cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 2-4 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and functionalized cellulose nanofibers was 40:15:16:5. A3. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.2:70; the mass ratio of nitration inhibitor particles to the mixture is 1:0.5; spraying is performed using a spray dryer with a spray pressure of 0.5 MPa and an inlet air temperature of 50°C; the shaking rate is 150 r / min and the shaking time is 15 min. A4. Modified cellulose nanofibers were added to deionized water and stirred until homogeneous. Zinc chloride and polydopamine-modified nitration inhibitor were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, deionized water, zinc chloride and polydopamine-modified nitration inhibitor was 3.6:100:0.3:2.

[0048] Comparative Example 5 The only difference between this comparative example and Example 3 is the preparation of the composite carrier, as detailed below: The composite carrier is prepared by the following steps: A1. Cellulose nanofibers and tannic acid were added to deionized water and stirred at 70°C for 30 min. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70°C for 10 min to obtain functionalized cellulose nanofibers. The mass ratio of cellulose nanofibers to tannic acid added to deionized water was 3:1:120. A2. Mix peanut vines and deionized water evenly, heat at 105℃ for 2 hours, and centrifuge at 4200 r / min for 30 minutes to obtain peanut vine extract. The mass ratio of peanut vines to deionized water is 6:80. Peanut vine extract was mixed thoroughly with 0.2 mol / L ferric chloride solution and 0.2 mol / L copper chloride solution. Functionalized cellulose nanofibers were then added, and the mixture was stirred at 30℃ and 80 r / min for 2-4 h. The precipitate was collected by centrifugation at 4200 r / min, washed three times with deionized water, and dried in a 70℃ oven for 10 min to obtain modified cellulose nanofibers. The mass ratio of peanut vine extract, ferric chloride solution, copper chloride solution, and functionalized cellulose nanofibers was 40:15:16:5. A3. Add dopamine to Tris-HCl buffer and stir until homogeneous to form a mixture. Spray the mixture onto the surface of the nitration inhibitor particles and shake until homogeneous to obtain a polydopamine-modified nitration inhibitor. The mass ratio of dopamine to Tris-HCl buffer is 0.2:70; the mass ratio of nitration inhibitor particles to the mixture is 1:0.5; spraying is performed using a spray dryer with a spray pressure of 0.5 MPa and an inlet air temperature of 50°C; the shaking rate is 150 r / min and the shaking time is 15 min. A4. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred until homogeneous. Polydopamine-modified nitration inhibitors were added, and the mixture was stirred at 25°C and 120 r / min for 3 h. The gel was collected by filtration and freeze-dried to obtain the composite carrier. The mass ratio of modified cellulose nanofibers, tannic acid, deionized water and polydopamine-modified nitration inhibitors was 3.3:0.6:100:2.

[0049] The performance of the bio-organic fertilizers prepared in Examples 1-3 and Comparative Examples 1-5 was then tested.

[0050] The prepared bio-organic fertilizer was weighed and mixed evenly with the soil, and then placed into flower pots. 20 wheat seeds were sown in each flower pot, for a total of five pots. After the wheat seedlings emerged, they were thinned out, leaving 5 wheat seedlings of uniform growth in each pot. After winter, the potted plants were buried in the soil to prevent frost damage to the wheat roots. After the wheat was harvested, the whole wheat plant was taken, dried, and weighed to obtain the dry matter mass. The nitrogen content of the wheat plant was determined by the Nessler colorimetric method, the phosphorus content was determined by the vanadium molybdenum yellow colorimetric method, and the potassium content was determined by the flame photometry method.

[0051] The test results are shown in Table 1 below.

[0052] Table 1 Performance testing of bio-organic fertilizers prepared in Examples 1-3 and Comparative Examples 1-5

[0053] As can be seen from the data in Table 1, the bio-organic fertilizers prepared in Examples 1-3 can increase crop yields, and the nutrient components in the bio-organic fertilizers are not easily lost.

[0054] Comparative Example 1 showed that when functionalized cellulose nanofibers were replaced with a composite carrier prepared from cellulose nanofibers and added to bio-organic fertilizer, the fertility of the bio-organic fertilizer decreased, and the nutrient content in wheat also decreased. This demonstrates that citric acid coating on the surface of cellulose nanofibers improves the surface activity of cellulose nanofibers, which is beneficial for synthesizing iron-copper nanocomposite materials with porous structures on the surface of cellulose nanofibers. This enhances the adsorption of nutrients in fertilizer, reduces fertilizer nutrient loss, and the excellent aspect ratio of cellulose nanofibers allows them to adsorb more nutrients, further enhancing the fertility of bio-organic fertilizer.

[0055] Comparative Example 2 showed that when the modified cellulose nanofibers were replaced with functionalized cellulose nanofibers to prepare a composite carrier, the fertility of the bio-organic fertilizer decreased, and the nutrient content of the wheat also decreased. This demonstrates that synthesizing an iron-copper nanocomposite material with a porous structure on the surface of cellulose nanofibers can provide good thermal insulation, prevent heat from penetrating into the composite carrier, and avoid the decomposition and inactivation of nitrification inhibitors caused by high-temperature granulation. Furthermore, the iron and copper elements in the iron-copper nanocomposite material can increase the fertility of the composite bio-fertilizer. In addition, the porous structure of the iron-copper nanocomposite material has high adsorption capacity, which can adsorb nutrients in the fertilizer, reduce nutrient loss, and improve the fertility of the bio-organic fertilizer.

[0056] Comparative Example 3 showed that when a composite carrier prepared by replacing the polydopamine-modified nitrification inhibitor with nitrification inhibitor particles was added to the bio-organic fertilizer, the fertility of the bio-organic fertilizer decreased, and the nutrient composition of the wheat also decreased. This demonstrates that the polydopamine membrane coating on the surface of the nitrification inhibitor particles is beneficial for the uniform dispersion of the nitrification inhibitor in the composite carrier, avoiding the easy decomposition and failure of the nitrification inhibitor under high-temperature granulation, which would affect the fertility of the fertilizer. Furthermore, the nitrification inhibitor can inhibit nitrifying bacteria and delay the hydrolysis of ammonium nitrogen in the compound fertilizer into ammonium carbonate, allowing ammonium nitrogen to exist in the compound fertilizer in a positively charged form for a longer period of time, thus reducing nitrogen fertilizer loss.

[0057] Comparative Example 4, where tannic acid was replaced by modified cellulose nanofibers, and Comparative Example 5, where zinc chloride was replaced by modified cellulose nanofibers, were used to prepare composite carriers. When these were added to bio-organic fertilizer, the fertility of the bio-organic fertilizer decreased, and the nutrient content in wheat also decreased. This demonstrates that the aerogel prepared by mixing modified cellulose nanofibers, tannic acid, zinc chloride, and polydopamine-modified nitrification inhibitors has a porous structure and high adsorption capacity for nutrients in fertilizers, further reducing nutrient loss. Furthermore, the high cross-linking density of the aerogel prevents the pores from collapsing during granulation, thus preventing the loss of adsorption capacity for nutrients in the compound fertilizer and reducing its fertility. In addition, the zinc ions in the composite carrier can also improve the fertility of the compound fertilizer.

[0058] Comparative Example 5 showed that when the microbial components prepared by replacing sawdust with urea were added to the bio-organic fertilizer, the wheat yield decreased and the nutrient content of the wheat also decreased. This proves that adding the diluted microbial fermentation liquid to the organic matter powder can prevent the microbial fermentation liquid from directly penetrating into part of the compound fertilizer and affecting the mixing with other parts of the compound fertilizer, thus improving the uniformity of microorganisms.

[0059] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw, characterized in that, It is prepared by the following steps: S1. Inoculate the compound microbial strain into the seed culture medium and carry out inoculation culture to obtain fermentation broth; S2. Mix livestock and poultry manure and straw to form compost material, add fermentation liquid to the compost material, and carry out fermentation composting to obtain manure fermentation products. S3. After drying and crushing, the fermented manure products are mixed with urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer and composite carrier. The mixture is stirred at 60-100 rpm for 5-10 minutes, granulated and dried to obtain bio-organic fertilizer. The composite carrier is obtained by surface modification of polydopamine with nitration inhibitors, followed by reaction with modified cellulose nanofibers, tannic acid, and zinc chloride. The modified cellulose nanofibers are obtained by synthesizing iron-copper nanocomposite materials on the surface of functionalized cellulose nanofibers.

2. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 1, characterized in that, The composite carrier is prepared by the following steps: A1. Add cellulose nanofibers and tannic acid to deionized water, stir and react at 60-70℃ for 20-30 min, filter, wash and dry to obtain functionalized cellulose nanofibers. A2. Mix peanut vines and deionized water evenly, heat at 95-105℃ for 1-2 hours, centrifuge to obtain peanut vine extract, mix peanut vine extract with ferric chloride solution and copper chloride solution evenly, add functionalized cellulose nanofibers, stir and react, collect precipitate by centrifugation, wash precipitate, dry to obtain modified cellulose nanofibers. A3. Add dopamine to Tris-HCl buffer, stir well to form a mixture, sprinkle the mixture onto the surface of nitrification inhibitor particles, shake well to obtain polydopamine modified nitrification inhibitor; A4. Modified cellulose nanofibers and tannic acid were added to deionized water and stirred until homogeneous. Zinc chloride and polydopamine-modified nitration inhibitors were added and stirred to react. The gel was collected by filtration and then freeze-dried to obtain the composite carrier.

3. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 2, characterized in that, In step A1, the cellulose nanofibers and tannic acid are added to deionized water in a mass ratio of (2-3):(0.5-1):(100-120).

4. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 2, characterized in that, In step A2, the mass ratio of peanut vines to deionized water is (4-6):(70-80); In step A2, the mass ratio of the peanut vine extract, ferric chloride solution, copper chloride solution and functionalized cellulose nanofibers is (30-40):(10-15):(12-16):(4-5).

5. The method for preparing fermented bio-organic fertilizer from livestock and poultry manure and straw according to claim 2, characterized in that, In step A3, the mass ratio of dopamine to Tris-HCl buffer is (0.1-0.2):(60-70); In step A3, the mass ratio of the nitrification inhibitor particles to the mixture is 1:(0.3-0.5); In step A3, the spraying is performed using a spray dryer with a spray pressure of 0.3-0.5 MPa and an inlet air temperature of 40-50℃; the oscillation rate is 80-150 r / min and the oscillation time is 10-15 min.

6. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 2, characterized in that, In step A4, the mass ratio of the modified cellulose nanofibers, tannic acid, deionized water, zinc chloride and polydopamine-modified nitration inhibitor is (2-3):(0.4-0.6):(80-100):(0.1-0.3):(1.5-2).

7. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 1, characterized in that, In step S1, the composite bacterial strain is obtained by mixing Bacillus subtilis, Bacillus licheniformis and Bacillus megaterium in a live bacterial count ratio of 1:1:(1-3); In step S1, the culture medium formula is as follows: glucose 15-20 g / L, corn starch 10-15 g / L, peptone 5-10 g / L, yeast extract 5-10 g / L, amino acids 8-10 g / L, magnesium sulfate 0.4-0.5 g / L, potassium dihydrogen phosphate 0.4-0.5 g / L, and the pH value of the culture medium is 7.0-7.2; In step S1, the inoculation culture specifically involves: an inoculation amount of 3-5%, and culture at 30-32℃ and 180-200rpm for 20-24 hours.

8. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 1, characterized in that, In step S2, the mass ratio of livestock and poultry manure to straw is (4-5):1, and the moisture content of the compost material is 50-65%. In step S2, the ratio of compost material to fermentation liquid is 1kg:5-10mL; In step S2, the fermentation and composting process specifically involves: first, turning the pile 1-2 times every 8 hours at a temperature of 20-25℃; second, turning the pile 1-2 times every 2 days at a temperature of 50-70℃; and finally, turning the pile 1-2 times every 5 days at a temperature of 20-50℃. When the temperature drops to 20-25℃, the composting process is completed.

9. The method for preparing bio-organic fertilizer from fermented livestock and poultry manure and straw according to claim 1, characterized in that, In step S3, the mass ratio of the manure fermentation product, urea, monoammonium phosphate, potassium dihydrogen phosphate, calcium magnesium phosphate fertilizer and composite carrier is (8-10):(15-20):(8-10):(8-10):(3-5):(10-15).

10. The bio-organic fertilizer prepared by the method of preparing bio-organic fertilizer by fermentation of livestock and poultry manure and straw as described in any one of claims 1-9.

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