Organic fertilizer obtained by fermenting animal waste and preparation method thereof

Abstract

The invention discloses an organic fertilizer obtained by fermenting animal waste and a preparation method thereof, and belongs to the technical field of preparation of organic fertilizers for agricultural production. Comprising the following steps: drying, crushing and sieving mixed animal manure to obtain mixed animal manure particles; the mixed animal waste particles, water and a complex microbial inoculant are mixed and fermented to obtain fermented animal waste; the preparation method comprises the following steps: mixing plant straws with an inorganic alkali solution, heating and stirring, adding acid to adjust to a neutral environment after heating and stirring, adding a mixed cross-linking agent, and heating and reacting to obtain a cross-linked protective film solution; mixing the fermented animal waste and the cross-linked protective film solution according to the mass ratio of 1: (1-1.5), stirring and drying to obtain the organic fertilizer. Through the technical means provided by the invention, the organic fertilizer with a slow release effect is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of preparing organic fertilizers for agricultural production, and in particular relates to an organic fertilizer obtained by fermenting animal excrement and a preparation method thereof. Background Art

[0002] Fertilizers are known as "food of food" and play an important role in increasing food production. The application of fertilizers is also a major leap in the history of human farming. In recent years, the amount of fertilizers used in my country has been increasing year by year. However, the large-scale use of fertilizers has brought many ecological problems: (1) Soil degradation: the soil aggregate structure is destroyed, resulting in soil compaction and barrenness; (2) Soil salinization: soil salt accumulation reduces soil microbial diversity and unbalanced crop nutrition, ultimately leading to reduced crop yields and quality; (3) Agricultural products are polluted: fertilizers are rich in nitrates, and large-scale application will cause nitrate accumulation in agricultural products, endangering the health of consumers; (4) Soil and water pollution: fertilizers contain a large amount of fast-acting nutrients that are easily soluble in water. As water is lost, groundwater and rivers become eutrophic. In addition, the long-term fertilization method of "heavy fertilizers and light organic fertilizers" has resulted in the inability to replenish humus in a timely manner, causing soil quality degradation and microecological damage, which has seriously restricted the sustainable development of modern agriculture. As people's environmental awareness increases and the country vigorously advocates environmental protection, people gradually reduce the use of chemical fertilizers in agricultural production and begin to explore the development of organic agriculture. Among them, organic fertilizers have begun to re-enter the public's field of vision.

[0003] Organic fertilizer refers to carbon-containing materials that are derived from plant or animal residues and their excrement and secretions, etc., and are applied to the soil after further fermentation and composting to provide plant nutrients as its main function. Organic fertilizer is a traditional farm fertilizer with a long history in my country and an important fertilizer in China's agricultural production. This is because it contains various nutrients and rich organic matter required by crops. After being applied to the soil, organic fertilizer can not only improve a variety of nutrients, but also improve the physical and chemical properties of the soil structure. It promotes soil microbial activity, matures the soil, effectively coordinates the water, fertilizer, gas and heat conditions in the soil, and improves soil fertility. The application of organic fertilizer is the main measure to ensure the sustainable and healthy development of agriculture. Organic fertilizer is a multi-source, multi-phase, multi-component, complex structure, and multi-functional composite artificial ecosystem. Its sources are extremely complex, and there are a variety of undecomposed or semi-decomposed biological residues: including human, livestock, poultry, and insect excrement; herbaceous, woody, aquatic, and marine animal and plant residues; urban domestic garbage, sludge, and humus soil; peat and humic acid mineral resources in nature, etc. These multi-source, extremely complex, and multi-functional organic substances also come from the land, becoming a very important link in the material circulation chain in the ecosystem.

[0004] Patent CN115010518A discloses a method for producing high-value organic fertilizer using cow dung. The invention adds a microbial mixed agent to the cow dung that has been pretreated with mineral salts and mixes them evenly to obtain a premix, composts and ferments the premix to obtain fermented cow dung; after the fermented cow dung is piled into a pile, earthworms are inoculated for cultivation, and a mixed solution of mineral salts and microbial mixed agents is sprayed during the cultivation period. After the cultivation is completed, the fermented cow dung on the top of the pile is taken, and the earthworms are picked out to obtain the high-value organic fertilizer; the obtained earthworms are put back into the remaining fermented cow dung pile for continued cultivation to obtain the high-value organic fertilizer again.

[0005] Patent CN105418172A discloses a method for preparing bio-organic fertilizer. The invention mainly utilizes fermented liquid microbial agents to ferment organic solid wastes such as livestock and poultry manure and straw to produce bio-organic fertilizer.

[0006] Patent CN105801187A discloses an integrated cow dung treatment and utilization method based on earthworm composting and vegetable planting. The invention plans vegetable planting land and selects vegetable varieties for sowing or planting according to the characteristics of earthworms that they like moisture and hate waterlogging; fermented cow dung is inoculated with Eisenia fetida, and the moisture content of the cow dung and the ambient temperature are maintained for pre-cultivation to obtain an earthworm inoculation unit mixed with earthworm castings, earthworms and earthworm cocoons; after the vegetables are planted or germinated, fresh cow dung piles are set between the vegetable rows, and the pre-prepared earthworm inoculation units are inoculated for composting; after the vegetables are mature, the vegetables are picked, the earthworms are collected, and the remaining earthworm castings organic fertilizer is applied to the soil through plowing, thereby realizing the in-situ treatment and utilization of cow dung.

[0007] The above invention realizes the utilization of organic waste such as animal manure, and improves the application value of organic fertilizer. However, in actual application, the organic fertilizer prepared by fermentation with the help of bacteria or other organisms cannot achieve the effect of slow release, resulting in too fast release of organic fertilizer, especially in the rainy season, when the organic fertilizer may flow to the deep layer of the soil or groundwater due to the effect of rainwater. This too fast release will cause a large loss of nutrients such as nitrogen, phosphorus, and potassium in the organic fertilizer, which will be less utilized by crops, resulting in restricted crop growth. In addition, the too fast loss of organic fertilizer will also lead to ecological problems such as eutrophication of water bodies due to the high content of elements such as nitrogen and phosphorus in the soil.

[0008] Therefore, developing an organic fertilizer with a slow-release effect has practical application significance for reducing the use of fertilizers, improving crop growth and reducing the ecological impact on the environment. Summary of the invention

[0009] In view of the deficiencies of the prior art, the present invention uses a composite bacterial agent to pre-ferment animal manure, and then treats plant straw containing high cellulose with alkali to break the glycosidic bonds of cellulose to form low-molecular-weight, water-soluble small-molecule sugars, and then, with the help of the good biocompatibility and biodegradability of sodium alginate, a cross-linking agent is used to form a cross-linked protective film solution, and then the fermented animal manure is mixed with the cross-linked protective film solution to achieve the wrapping of the fermented animal manure, thereby obtaining an organic fertilizer with a slow-release effect, which solves the technical problems raised in the background technology. Specifically, the technical solution of the present invention includes the following steps:

[0010] A method for preparing organic fertilizer obtained by fermenting animal feces, the preparation method comprising the following steps:

[0011] The mixed animal feces are dried, crushed and sieved to obtain mixed animal feces pellets;

[0012] The mixed animal feces pellets, water and composite bacterial agent are mixed and fermented in a mass ratio of 1:0.6-1.5:0.005-0.01 to obtain fermented animal feces;

[0013] The plant straw is mixed with an inorganic alkali solution and heated and stirred, after the heating and stirring are completed, acid is added to adjust to a neutral environment, and then a mixed cross-linking agent is added and heated to react to obtain a cross-linked protective film solution;

[0014] The fermented animal excrement and the cross-linked protective film solution are mixed, stirred and dried in a mass ratio of 1:1 to 1.5 to obtain the organic fertilizer.

[0015] Furthermore, the mixed animal manure consists of cow manure, pig manure, chicken manure and sheep manure, and the mass ratio of cow manure: pig manure: chicken manure: sheep manure is 1:1:0.4-0.6:0.4-0.6.

[0016] Furthermore, the composite bacterial agent is composed of a mixture of Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonii, and the mass ratio of Bacillus amyloliquefaciens: Candida lipolytica: Aspergillus carbonii is 1:1:1.

[0017] Furthermore, the strain preservation number of the Bacillus amyloliquefaciens is CICC 20604, the strain preservation number of the Candida lipolytica is CICC 32245, and the strain preservation number of the Aspergillus carbonii is CICC 41254.

[0018] Furthermore, the mixed fermentation conditions include a fermentation temperature of 28°C to 33°C, a fermentation time of 5 to 8 days, and a fermentation ventilation volume of 0.3 m 3 / h~0.5m 3 / h.

[0019] Furthermore, the plant straw is sorghum straw, corn straw or wheat straw.

[0020] Furthermore, the inorganic alkaline solution includes sodium hydroxide solution or potassium hydroxide solution.

[0021] Furthermore, the mass concentration of the inorganic alkali solution is 1% to 2%.

[0022] Furthermore, the mass ratio of the plant straw to the inorganic alkaline solution is 1:10-20.

[0023] Furthermore, the heating and stirring conditions include a heating temperature of 80° C. to 95° C., a stirring speed of 200 r / min to 300 r / min, and a stirring time of 110 min to 140 min.

[0024] Furthermore, the acid used for the acidification adjustment includes malic acid, citric acid or acetic acid.

[0025] Furthermore, the mixed cross-linking agent is composed of sodium alginate and glutaraldehyde mixed in a mass ratio of 1:1.

[0026] Furthermore, the mass ratio of the mixed cross-linking agent to the plant straw is 0.01-0.025:1.

[0027] Furthermore, the conditions of the heating reaction include a heating temperature of 75° C. to 85° C. and a reaction time of 1 h to 2 h.

[0028] The invention discloses an organic fertilizer prepared by a method for preparing organic fertilizer obtained by fermenting animal excrement.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The mixed animal manure used in the present invention contains a large amount of nutrients such as starch, protein and cellulose. Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonii can produce a variety of bioactive enzymes that degrade nutrients such as starch, protein and cellulose, thereby improving the utilization rate of nutrients. The synergistic fermentation between Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonii not only increases the release of total nutrients such as nitrogen, phosphorus and potassium in animal manure, but also has a good promoting effect on improving the fertility of organic fertilizers.

[0031] (2) The present invention performs alkali treatment on plant straw containing a high cellulose content, thereby breaking the β-1,4-glycosidic bonds in the cellulose and decomposing it to form low-molecular-weight small-molecule sugars with good water solubility. Then, sodium alginate with good biocompatibility and biodegradability is used as the raw material for constructing a cross-linked protective film solution with a sustained-release effect. Under certain reaction conditions, the aldehyde groups on glutaraldehyde can be condensed and cross-linked with the hydroxyl groups on the decomposed small-molecule sugars and the hydroxyl groups on the sodium alginate, thereby preparing a cross-linked protective film solution. Finally, fermented animal feces and the cross-linked protective film solution are mixed and stirred, so that the cross-linked protective film solution can wrap the fermented animal feces. With the help of this wrapping effect, the organic fertilizer is slowly released, thereby improving the utilization efficiency of the organic fertilizer. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below through the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0034] Bacillus amyloliquefaciens with strain collection number CICC 20604, Candida lipolytica with strain collection number CICC 32245, Aspergillus carbonii with strain collection number CICC 41254, Bacillus subtilis with strain collection number CICC 24713, Lactobacillus acidophilus with strain collection number CICC 6093 and Streptomyces with strain collection number CICC 11059 were all purchased from China Industrial Microbiological Culture Collection Center.

[0035] Preparation Example 1:

[0036] Preparation of compound bacterial agent:

[0037] (1) Use a sterilized inoculation loop to dip Bacillus amyloliquefaciens and inoculate it on a beef extract peptone solid medium (3 g beef extract, 10 g peptone, 5 g sodium chloride, 16 g agar and water to 1000 mL) plate to spread and streak. After streaking, place the medium plate in a 32°C incubator for activation and culture for 24 h. Then use a sterilized inoculation loop to dip the activated Bacillus amyloliquefaciens and inoculate it into a beef extract peptone liquid medium (3 g beef extract, 10 g peptone, 5 g sodium chloride, 16 g agar and water to 1000 mL) and place it in a 35°C incubator for shaking culture until the concentration of the test bacterial solution reaches 1×10 6CFU / mL, ready to use;

[0038] Use a sterilized inoculation loop to dip the Candida lipolytica into beef extract peptone solid medium (3 g beef extract, 10 g peptone, 5 g sodium chloride, 16 g agar and water to 1000 mL) and spread the streaking lines. After the streaking is completed, place the medium plate in a 28°C incubator for activation and culture for 24 hours. Then use a sterilized inoculation loop to dip the activated Candida lipolytica and inoculate it into beef extract peptone liquid medium (3 g beef extract, 10 g peptone, 5 g sodium chloride, 16 g agar and water to 1000 mL) and place it in a 28°C incubator for shaking culture until the concentration of the test bacterial solution reaches 1×10 6 CFU / mL, ready to use;

[0039] Use a sterilized inoculation loop to dip carbon black Aspergillus and inoculate it into beef extract peptone solid medium (3g beef extract, 10g peptone, 5g sodium chloride, 16g agar and water to 1000mL) plate to spread and streak. After streaking, place the medium plate in a 25°C incubator for activation and culture for 24h. Use a sterilized inoculation loop to dip the activated carbon black Aspergillus and inoculate it into beef extract peptone liquid medium (3g beef extract, 10g peptone, 5g sodium chloride, 16g agar and water to 1000mL) and place it in a 28°C incubator for shaking culture until the concentration of the test bacteria reaches 1×10 6 CFU / mL, ready to use;

[0040] The above three bacterial solutions were mixed in a mass ratio of 1:1:1 to obtain a composite bacterial agent.

[0041] Preparation Example 2:

[0042] Preparation of compound bacterial agent:

[0043] The Bacillus amyloliquefaciens in Preparation Example 1 was replaced by Bacillus subtilis with strain deposit number CICC 24713, and the other conditions were the same as those in Preparation Example 1.

[0044] Preparation Example 3:

[0045] The Candida lipolytica in Preparation Example 1 was replaced by Lactobacillus acidophilus with a strain preservation number of CICC 6093, and the Aspergillus carbonii in Preparation Example 1 was replaced by Streptomyces with a strain preservation number of CICC 11059. The other conditions were the same as those in Preparation Example 1.

[0046] Embodiment 1:

[0047] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0048] Weigh 5kg of cow dung, 5kg of pig manure, 2kg of chicken manure and 2kg of sheep manure to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for drying for 12 hours. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 3kg of water, mix and stir to wet, and then evenly spray 25g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 28°C, and use a blower to adjust the ventilation flow rate to 0.3m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 5 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0049] Take 1kg of sorghum straw and crush it with a crusher, add 10kg of sodium hydroxide solution (mass concentration is 1%) to mix, then place it in a temperature environment of 80℃ and stir it at a speed of 200r / min for 110min. After the heating and stirring treatment, naturally cool it to room temperature, then add malic acid to adjust until the pH reaches neutrality, then add 10g of mixed cross-linking agent (mixed by 5g sodium alginate and 5g glutaraldehyde) to the mixed solution in the neutral environment and heat it to 75℃, stir the reaction at a speed of 100r / min for 1h to obtain a cross-linked protective film solution. Take 2kg of fermented animal feces and 2kg of cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0050] Embodiment 2:

[0051] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0052] Weigh 5kg of cow dung, 5kg of pig dung, 2kg of chicken dung and 2kg of sheep dung to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for drying for 12 hours. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 3.5kg of water, mix and stir to wet, and then evenly spray 30g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 28°C, and use a blower to adjust the ventilation flow rate to 0.4m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 5 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0053] Take 1kg of sorghum straw and crush it with a crusher, add 12kg of sodium hydroxide solution (mass concentration is 1.2%) to mix, then place it in a temperature environment of 80℃ and stir it at a speed of 200r / min for 120min. After the heating and stirring treatment, cool it naturally to room temperature, then add malic acid to adjust until the pH reaches neutrality, then add 10g of mixed cross-linking agent (mixed by 5g sodium alginate and 5g glutaraldehyde) to the mixed solution in the neutral environment and heat it to 75℃, stir the reaction at a speed of 100r / min for 1.2h to obtain a cross-linked protective film solution. Take 2kg of fermented animal feces and 2.2kg of cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0054] Embodiment 3:

[0055] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0056] Weigh 5kg of cow dung, 5kg of pig dung, 2.5kg of chicken dung and 2.5kg of sheep dung to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for drying for 16 hours. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 4kg of water, mix and stir to wet, and then evenly spray 35g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 30°C, and use a blower to adjust the ventilation flow rate to 0.4m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 5 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0057] Take 1kg corn stalks and crush them with a pulverizer, add 14kg sodium hydroxide solution (mass concentration is 1.4%) to mix, then place it in an 85℃ temperature environment and stir it at a speed of 250r / min for 120min. After the heating and stirring treatment, naturally cool it to room temperature, then add malic acid to adjust until the pH reaches neutrality, then add 15g mixed cross-linking agent (mixed by 7.5g sodium alginate and 7.5g glutaraldehyde) to the mixed solution in the neutral environment and heat it to 75℃, stir the reaction at a speed of 100r / min for 1.4h to obtain a cross-linked protective film solution. Take 2kg fermented animal feces and 2.4kg cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0058] Embodiment 4:

[0059] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0060] Weigh 5kg of cow dung, 5kg of pig dung, 2.5kg of chicken dung and 2.5kg of sheep dung to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for 16 hours to dry. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 4.5kg of water, mix and stir to wet, and then evenly spray 40g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 30°C, and use a blower to adjust the ventilation flow rate to 0.4m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 6 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0061] Take 1kg corn stalks and crush them with a pulverizer, add 16kg sodium hydroxide solution (mass concentration is 1.6%) to mix, then place it in an 85°C temperature environment and stir it at a speed of 250r / min for 130min. After the heating and stirring treatment is completed, it is naturally cooled to room temperature, and then citric acid is added to adjust until the pH reaches neutral. At this time, 15g of mixed cross-linking agent (mixed by 7.5g sodium alginate and 7.5g glutaraldehyde) is added to the mixed solution in a neutral environment and heated to 80°C, and stirred at a speed of 100r / min for 1.6h to obtain a cross-linked protective film solution. Take 2kg of fermented animal feces and 2.6kg of cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0062] Embodiment 5:

[0063] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0064] Weigh 5kg of cow dung, 5kg of pig dung, 3kg of chicken dung and 3kg of sheep dung to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for drying for 20 hours. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 5.5kg of water, mix and stir to wet, and then evenly spray 45g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 32°C, and use a blower to adjust the ventilation flow rate to 0.4m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 7 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0065] Take 1kg corn stalks and crush them with a pulverizer, add 18kg potassium hydroxide solution (mass concentration is 1.8%) to mix, then place it in a temperature environment of 90℃ and stir it at a speed of 300r / min for 130min. After the heating and stirring treatment, cool it naturally to room temperature, then add citric acid to adjust until the pH reaches neutrality, then add 20g mixed cross-linking agent (mixed by 10g sodium alginate and 10g glutaraldehyde) to the mixed solution in the neutral environment and heat it to 80℃, stir the reaction at a speed of 100r / min for 1.8h to obtain a cross-linked protective film solution. Take 2kg fermented animal feces and 2.8kg cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0066] Embodiment 6:

[0067] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0068] Weigh 5kg of cow dung, 5kg of pig dung, 3kg of chicken dung and 3kg of sheep dung to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for drying for 20 hours. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 6.5kg of water, mix and stir to wet, and then evenly spray 50g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 32°C, and use a blower to adjust the ventilation flow rate to 0.5m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 7 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0069] Take 1kg of wheat straw and crush it with a pulverizer, add 20kg of potassium hydroxide solution (mass concentration is 2%) to mix, then place it in a temperature environment of 90℃ and stir it at a speed of 300r / min for 140min. After the heating and stirring treatment is completed, it is naturally cooled to room temperature, and then acetic acid is added to adjust until the pH reaches neutral. At this time, 20g of mixed cross-linking agent (mixed by 10g sodium alginate and 10g glutaraldehyde) is added to the mixed solution in the neutral environment and heated to 80℃, and stirred at a speed of 100r / min for 2h to obtain a cross-linked protective film solution. Take 2kg of fermented animal feces and 3kg of cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0070] Embodiment 7:

[0071] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0072] Weigh 5kg of cow dung, 5kg of pig dung, 3kg of chicken dung and 3kg of sheep dung to form mixed animal manure, and then place the mixed animal manure in a hot air environment at 70°C for drying for 20 hours. After drying, grind and crush, and filter with a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5kg of mixed animal manure particles, add 7.5kg of water, mix and stir to wet, and then evenly spray 50g of the composite bacterial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite bacterial agent is completed, place the mixed animal manure particles in a temperature environment of 33°C, and use a blower to adjust the ventilation flow rate to 0.5m 3 / h, ventilation and fermentation for 30 minutes every 5 hours, 4 times a day, before each ventilation and fermentation, the mixed animal feces particles are turned over to make them contact evenly, and fermentation is continued for 8 days. After the fermentation is completed, the fermentation product is taken out to obtain fermented animal feces.

[0073] Take 1kg of wheat straw and crush it with a pulverizer, add 20kg of potassium hydroxide solution (mass concentration is 2%) to mix, then place it in a temperature environment of 95℃ and stir it at a speed of 300r / min for 140min. After the heating and stirring treatment is completed, it is naturally cooled to room temperature, and then acetic acid is added to adjust until the pH reaches neutral. At this time, 25g of mixed cross-linking agent (mixed by 12.5g sodium alginate and 12.5g glutaraldehyde) is added to the mixed solution in the neutral environment and heated to 85℃, and stirred at a speed of 100r / min for 2h to obtain a cross-linked protective film solution. Take 2kg of fermented animal feces and 3kg of cross-linked protective film solution, mix and stir, and then dry to obtain organic fertilizer.

[0074] Comparative Example 1:

[0075] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0076] The composite bacterial agent in Example 7 was replaced by the composite bacterial agent obtained in Preparation Example 2, and the other conditions remained the same as in Example 7.

[0077] Comparative Example 2:

[0078] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0079] The composite bacterial agent in Example 7 was replaced by the composite bacterial agent obtained in Preparation Example 3, and the other conditions remained the same as in Example 7.

[0080] Comparative Example 3:

[0081] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0082] The amount of water used to wet the mixed animal feces pellets in Example 7 was increased to 10 kg, and the other conditions remained the same as in Example 7.

[0083] Comparative Example 4:

[0084] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0085] The amount of potassium hydroxide solution in Example 7 was reduced to 5 kg, and the other conditions were kept consistent with Example 7.

[0086] Comparative Example 5:

[0087] A method for preparing organic fertilizer obtained by fermenting animal feces, specifically comprising the following steps:

[0088] When the amount of the mixed cross-linking agent in Example 7 was increased to 50 g, it was found that the cross-linked protective film solution after cooling was severely gelled. This may be because the cross-linked network structure was too dense, resulting in poor fluidity of the solution and inability to mix with fermented animal feces.

[0089] The organic fertilizers obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were measured for the mass fractions of organic matter and total nutrients (N+P205+K20) according to the Agricultural Industry Standard NY525-2021 of the People's Republic of China. The results are shown in the following table:

[0090] Sources Organic matter (%) Total nutrients (%) Example 1 40.4 5.04 Example 2 43.6 5.09 Example 3 47.4 5.22 Example 4 50.1 5.31 Example 5 54.6 5.52 Example 6 56.3 5.58 Example 7 41.5 5.62 Comparative Example 1 19.4 3.47 Comparative Example 2 22.1 3.65 Comparative Example 3 20.6 3.52 Comparative Example 4 53.7 5.42

[0091] From the above results we can see that:

[0092] (1) The composite bacterial agent constructed by the present invention has a good ability to ferment mixed animal feces, so that the mixed animal feces can be decomposed by the composite bacterial agent of the present invention to release more organic matter and improve the release of total nutrients such as nitrogen, phosphorus and potassium.

[0093] (2) Comparative Examples 1 and 2 show that although other bacterial species have the ability to ferment, the organic matter and total nutrient contents are low due to the different growth and reproduction environments and the structural composition of nutrients, which do not meet the use requirements.

[0094] (3) Comparative Example 3 shows that excessively high water content causes a significant decrease in the content of organic matter and total nutrients. This may be because the water content in this system has an inhibitory effect on the fermentation of the bacteria.

[0095] (4) It can be seen from Comparative Example 4 that the content of organic matter and total nutrients is good, but slightly worse than that of Example 7. This may be due to the lower use of potassium hydroxide solution and less cellulose decomposition, which leads to a decrease in the ability of the strain to utilize the nutrients in the straw.

[0096] The organic fertilizers obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were subjected to nitrogen static water release test according to GBT 23348-2009 Slow-release Fertilizer:

[0097] Test method: Place 10g of organic fertilizer in 1000mL of still water, and take samples on the 3rd, 10th, 20th and 30th days to measure the cumulative release rate of nitrogen. The results are as follows:

[0098]

[0099] From the above results we can see that:

[0100] (1) The organic fertilizer prepared by the present invention has a good slow-release effect by forming a condensation cross-linking structure between sodium alginate, glutaraldehyde and small molecular sugars after cellulose decomposition, and then wrapping it on the surface of fermented animal feces.

[0101] (2) It can be seen from Comparative Examples 1, 2 and 3 that although the obtained organic fertilizer has a good slow-release effect, the bacterial strains in this environment have poor fermentation efficiency due to changes in the environment such as nutrients and water content, and the organic matter and total nutrient content are low. The nitrogen content finally released is also low, which does not meet the use requirements.

[0102] (3) It can be seen from Comparative Example 4 that a lower amount of potassium hydroxide solution has a lower efficiency in decomposing cellulose, resulting in less cellulose cross-linked with sodium alginate and glutaraldehyde, less formation of sustained-release structure, and poorer sustained-release effect.

[0103] The organic fertilizers obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were mixed at a rate of 10 mg of organic fertilizer per 10 g of soil to form a soil-fertilizer mixture. A 10 cm high dry soil sample was placed at the bottom of a plexiglass tube with an inner diameter of 7.5 cm (the bottom was sealed with an iron filter), a 5 cm high middle layer of the soil-fertilizer mixture, and a 1 cm thick top layer of quartz sand. The weight W1 at this time was recorded. Water was then added to the plexiglass tube until water just began to seep out of the bottom. After standing until water no longer seeped out of the bottom, the weight W2 was recorded. (W2-W1) / W1 was the water retention rate. The weights W3, W4, W5, W6, W7, W8, W9, W10, W11, W12, W13, W14, W15, W16, W17, W18, W19, W20, W21, W22, W23, W24, W25, W26, W27, W28, W29, W30, W31, W32, W33, W34, W35, W36, W37, W38, W39, W40, W41, W42, W43, W44, W45, W46, W47, W48, W49, W50, W51, W52, W53, W54, W55, W56, W57, W58, W59, W60, W61, W71, W72, W73, W74, W75 10 , W 20 and W 30 , calculate the 3rd day (W3-W1) / W1, the 10th day (W 10 -W1) / W1, 20th day (W 20 -W1) / W1 and 30th day (W 30 -W1) / W1 water retention rate, the results are as follows:

[0104]

[0105]

[0106] From the above results, it can be seen that the organic fertilizer with slow-release function constructed by the condensation cross-linking structure formed between sodium alginate, glutaraldehyde and small molecular sugars after cellulose decomposition has a good effect in water retention rate. This may be because the condensation cross-linking structure can attract water molecules through physical adsorption such as hydrogen bonding, and the improvement of water retention rate has a positive effect in preventing the rapid loss of fertilizer, improving crop growth and reducing the impact on eutrophication of the water environment.

[0107] The above-described embodiments provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected.

Claims

1. A method for preparing organic fertilizer obtained by fermenting animal feces, characterized in that: The preparation method comprises the following steps: The mixed animal feces are dried, crushed and sieved to obtain mixed animal feces pellets; The mixed animal feces pellets, water and composite bacterial agent are mixed and fermented in a mass ratio of 1:0.6-1.5:0.005-0.01 to obtain fermented animal feces; The plant straw is mixed with an inorganic alkali solution and heated and stirred, after the heating and stirring are completed, acid is added to adjust to a neutral environment, and then a mixed cross-linking agent is added and heated to react to obtain a cross-linked protective film solution; The fermented animal excrement and the cross-linked protective film solution are mixed, stirred and dried in a mass ratio of 1:1 to 1.5 to obtain the organic fertilizer.

2. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The mixed animal manure consists of cow manure, pig manure, chicken manure and sheep manure, and the mass ratio of the cow manure: pig manure: chicken manure: sheep manure is 1:1:0.4-0.6:0.4-0.

6.

3. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The composite bacterial agent is composed of a mixture of Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonii, and the mass ratio of Bacillus amyloliquefaciens: Candida lipolytica: Aspergillus carbonii is 1:1:

1.

4. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The mixed fermentation conditions include a fermentation temperature of 28°C to 33°C, a fermentation time of 5 to 8 days, and a fermentation ventilation volume of 0.3 m 3 / h~0.5m 3 / h.

5. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The mass ratio of the plant straw to the inorganic alkaline solution is 1:10-20.

6. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The heating and stirring conditions include a heating temperature of 80° C. to 95° C., a stirring speed of 200 r / min to 300 r / min, and a stirring time of 110 min to 140 min.

7. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The mixed cross-linking agent is composed of sodium alginate and glutaraldehyde mixed in a mass ratio of 1:

1.

8. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The mass ratio of the mixed cross-linking agent to the plant straw is 0.01-0.025:

1.

9. The method for preparing organic fertilizer obtained by fermenting animal feces according to claim 1, characterized in that: The conditions of the heating reaction include a heating temperature of 75° C. to 85° C. and a reaction time of 1 h to 2 h.

10. An organic fertilizer prepared by the method for preparing an organic fertilizer obtained by fermenting animal feces according to any one of claims 1 to 9.

Images