An organic fertilizer obtained by fermenting animal manure and its preparation method

Abstract

The present invention discloses an organic fertilizer obtained by fermenting animal manure and a preparation method thereof, belonging to the technical field of the preparation of organic fertilizers for agricultural production. The method comprises the following steps: drying, crushing and sieving the mixed animal manure to obtain mixed animal manure particles; mixing the mixed animal manure particles, water and a compound microbial agent for fermentation to obtain fermented animal manure; mixing plant straws with an inorganic alkali solution, heating and stirring, adjusting to a neutral environment with an acid after the heating and stirring are completed, and then adding a mixed crosslinking agent for heating reaction to obtain a crosslinked protective film solution; mixing the fermented animal manure and the crosslinked protective film solution in a mass ratio of 1:1 to 1.5, stirring, and drying to obtain the organic fertilizer. By means of the technical means of the present invention, an 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. In this invention, a microbial mixed inoculant is added to cow dung pretreated with mineral salts and mixed evenly to obtain a premix. The premix is composted and fermented to obtain fermented cow dung. The fermented cow dung is piled into a heap and inoculated with earthworms for cultivation. During the cultivation period, a mixed solution of mineral salts and microbial mixed inoculant is sprayed. After the cultivation is completed, the fermented cow dung above the heap 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 heap for continuous cultivation to obtain the high-value organic fertilizer again.

[0005] Patent CN105418172A discloses a preparation method of biological organic fertilizer. This invention mainly uses a fermented liquid microbial inoculant to carry out a fermentation reaction on organic solid wastes such as livestock and poultry manure and straw to obtain biological organic fertilizer.

[0006] Patent CN105801187A discloses an integrated treatment and utilization method of cow dung based on vermicomposting and vegetable planting. According to the characteristics of earthworms that like humidity but avoid waterlogging, the vegetable planting garden is planned, and vegetable varieties are selected for sowing or planting. Fermented cow dung is taken and inoculated with Eisenia fetida, and pre-cultured while maintaining the moisture content of the cow dung and the environmental temperature to obtain an earthworm inoculation unit mixed with earthworm manure, earthworms and earthworm cocoons. After the vegetables are planted or emerge, fresh cow dung heaps are set up between the vegetable rows, and the pre-prepared earthworm inoculation unit is inoculated for composting treatment. After the vegetables are mature, the vegetables are picked, the earthworms are collected, and the remaining earthworm manure organic fertilizer is applied to the soil by plowing, realizing the in-situ treatment and utilization of cow dung.

[0007] The above inventions have realized the utilization of organic wastes such as animal manure and improved the application value of organic fertilizers. However, in actual application, the organic fertilizers prepared by fermentation with the help of strains or other organisms cannot achieve the slow-release effect, resulting in too fast release of organic fertilizers. Especially during the rainy season, the organic fertilizers may flow into the deep layer of the soil or groundwater due to the action of rainwater. This too fast release will cause more loss of nutrients such as nitrogen, phosphorus, and potassium in the organic fertilizers, less utilization by crops, and limited crop growth. Moreover, the too fast loss of organic fertilizers will also lead to ecological problems such as eutrophication of water bodies due to high contents of nitrogen, phosphorus and other elements 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 pre-ferments animal feces using a composite bacterium agent, and then alkali-treats plant straws containing high cellulose to break the glycosidic bonds of cellulose to form small molecules of sugar with low molecular weight and high water solubility. Then, by virtue of the good biocompatibility and biodegradability of sodium alginate, a cross-linked protective film solution is formed through treatment with a cross-linking agent. Subsequently, the fermented animal feces are mixed with the cross-linked protective film solution to achieve the encapsulation of the fermented animal feces, thereby obtaining an organic fertilizer with a slow-release effect, and solving the technical problems proposed in the background art. Specifically, the technical solution of the present invention includes the following steps:

[0010] A preparation method of an organic fertilizer obtained by fermenting animal feces, the preparation method including the following steps:

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

[0012] The mixed animal feces particles, water and the composite bacterium 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 straws are 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 for reaction to obtain a cross-linked protective film solution;

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

[0015] Further, the mixed animal feces are composed of cow dung, pig dung, chicken dung and sheep dung, and the mass ratio of cow dung: pig dung: chicken dung: sheep dung is 1: 1: 0.4-0.6: 0.4-0.6.

[0016] Further, the composite bacterium agent is composed of Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonarius, and the mass ratio of Bacillus amyloliquefaciens: Candida lipolytica: Aspergillus carbonarius is 1: 1: 1.

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

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

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

[0020] Further, the inorganic base solution includes sodium hydroxide solution or potassium hydroxide solution.

[0021] Further, the mass concentration of the inorganic base solution is 1% - 2%.

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

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

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

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

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

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

[0028] An organic fertilizer prepared by a preparation method of an organic fertilizer obtained by fermenting animal feces.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) The mixed animal feces adopted by the present invention contain more nutritional components such as starch, protein and cellulose. Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonarius can produce various bioactive enzymes for degrading nutritional components such as starch, protein and cellulose, improving the utilization rate of nutritional components. Through the synergistic cooperation and fermentation among Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonarius, not only the release amount of total nutrients such as nitrogen, phosphorus and potassium in animal feces is increased, but also it has a good promoting effect on improving the fertility of organic fertilizers.

[0031] (2) In the present invention, plant straws with a relatively high cellulose content are subjected to alkali treatment, causing the cleavage of β-1,4-glycosidic bonds in cellulose and decomposing 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 slow-release effect. Under certain reaction conditions, the aldehyde groups on glutaraldehyde can undergo condensation cross-linking with the hydroxyl groups on the decomposed small molecule sugars and the hydroxyl groups on sodium alginate, thereby preparing a cross-linked protective film solution. Finally, the fermented animal feces are mixed and stirred with the cross-linked protective film solution, enabling the cross-linked protective film solution to wrap the fermented animal feces. With the help of this wrapping effect, the slow release of the organic fertilizer is achieved, and the utilization efficiency of the organic fertilizer is improved. Detailed implementation manners

[0032] Next, through the examples of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described examples are only a part of the examples of the present invention, rather than all the examples. Based on the examples in the present invention, all other examples obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

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

[0034] Bacillus amyloliquefaciens with the strain preservation number of CICC 20604, Candida lipolytica with the strain preservation number of CICC 32245, Aspergillus carbonarius with the strain preservation number of CICC 41254, Bacillus subtilis with the strain preservation number of CICC 24713, Lactobacillus acidophilus of CICC 6093, and Streptomyces with the strain preservation number of CICC 11059 are all purchased from the China Center for Industrial Culture Collection.

[0035] Preparation Example 1:

[0036] Preparation of the compound bacterium agent:

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

[0038] Dip the inoculation loop after sterilization into Candida lipolytica and inoculate it on the plate of beef extract peptone solid medium (3 g of beef extract, 10 g of peptone, 5 g of sodium chloride, 16 g of agar and make up to 1000 mL with water) for streaking. After streaking, place the culture medium plate in an incubator at 28 °C for activation culture for 24 h; then dip the inoculation loop after sterilization into the above-activated Candida lipolytica, inoculate it into the beef extract peptone liquid medium (3 g of beef extract, 10 g of peptone, 5 g of sodium chloride, 16 g of agar and make up to 1000 mL with water), and place it in an incubator at 28 °C for shaking culture until the detected bacterial liquid concentration reaches 1×10 6 CFU / mL, and it can be used;

[0039] Dip the inoculation loop after sterilization into Aspergillus carbonarius and inoculate it on the plate of beef extract peptone solid medium (3 g of beef extract, 10 g of peptone, 5 g of sodium chloride, 16 g of agar and make up to 1000 mL with water) for streaking. After streaking, place the culture medium plate in an incubator at 25 °C for activation culture for 24 h; then dip the inoculation loop after sterilization into the above-activated Aspergillus carbonarius, inoculate it into the beef extract peptone liquid medium (3 g of beef extract, 10 g of peptone, 5 g of sodium chloride, 16 g of agar and make up to 1000 mL with water), and place it in an incubator at 28 °C for shaking culture until the detected bacterial liquid concentration reaches 1×10 6 CFU / mL, and it can be used;

[0040] Mix the above three kinds of bacterial liquids according to the mass ratio of 1:1:1 to obtain a composite microbial agent.

[0041] Preparation Example 2:

[0042] Preparation of the composite microbial agent:

[0043] Replace Bacillus amyloliquefaciens in Preparation Example 1 with Bacillus subtilis with the strain preservation number of CICC 24713, and keep the other conditions the same as those in Preparation Example 1.

[0044] Preparation Example 3:

[0045] Replace Candida lipolytica in Preparation Example 1 with Lactobacillus acidophilus with the strain preservation number of CICC 6093, and replace Aspergillus carbonarius in Preparation Example 1 with Streptomyces sp. with the strain preservation number of CICC 11059, and keep the other conditions the same as those in Preparation Example 1.

[0046] Example 1:

[0047] A preparation method of an organic fertilizer obtained by fermenting animal feces, specifically including the following process:

[0048] Weigh 5 kg of cow dung, 5 kg of pig manure, 2 kg of chicken manure and 2 kg of sheep manure and mix them to form mixed animal manure. Then, place the mixed animal manure in a hot air environment at 70 °C and dry it for 12 h. After drying, grind and crush it, and sieve it through a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5 kg of the mixed animal manure particles, add 3 kg of water, mix and stir to wet them, and then evenly spray 25 g of the composite microbial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite microbial 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 0.3 m 3 / h. Ventilation fermentation is carried out once every 5 h for 30 min, and it is processed 4 times a day. Before each ventilation fermentation, turn over the mixed animal manure particles to make them contact evenly, and ferment continuously for 5 days. After fermentation is completed, take out the fermentation product to obtain fermented animal manure.

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

[0050] Example 2:

[0051] A preparation method of an organic fertilizer obtained by fermenting animal manure specifically includes the following process:

[0052] Weigh 5 kg of cow dung, 5 kg of pig manure, 2 kg of chicken manure and 2 kg of sheep manure and mix them to form mixed animal manure. Then, place the mixed animal manure in a hot air environment at 70 °C and dry it for 12 h. After drying, grind and crush it, and sieve it through a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5 kg of the mixed animal manure particles, add 3.5 kg of water, mix and stir to wet them, and then evenly spray 30 g of the composite microbial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite microbial 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 0.4 m 3 / h. Ventilation fermentation is carried out once every 5 h for 30 min, and it is processed 4 times a day. Before each ventilation fermentation, turn over the mixed animal manure particles to make them contact evenly, and ferment continuously for 5 days. After fermentation is completed, take out the fermentation product to obtain fermented animal manure.

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

[0054] Example 3:

[0055] A preparation method of organic fertilizer obtained by fermenting animal feces, specifically including the following process:

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

[0057] After crushing 1 kg of corn straw with a crusher, add 14 kg of sodium hydroxide solution (mass concentration of 1.4%) and mix. Then place it in a temperature environment of 85 °C and stir at a speed of 250 r / min for 120 min. After the heating and stirring treatment, let it cool naturally to room temperature, and then add malic acid for adjustment until the pH reaches neutral. At this time, add 15 g of mixed cross-linking agent (composed of 7.5 g of sodium alginate and 7.5 g of glutaraldehyde) to the mixed solution in the neutral environment and heat to 75 °C, and stir and react at a speed of 100 r / min for 1.4 h to obtain a cross-linked protective film solution. Take 2 kg of fermented animal feces and 2.4 kg of cross-linked protective film solution and mix and stir, and then dry to obtain organic fertilizer.

[0058] Example 4:

[0059] A preparation method of an organic fertilizer obtained by fermenting animal manure, specifically including the following process:

[0060] Weigh 5 kg of cow dung, 5 kg of pig manure, 2.5 kg of chicken manure and 2.5 kg of sheep manure and mix them to form mixed animal manure. Then place the mixed animal manure in a hot air environment at 70 °C for 16 h of drying treatment. After drying, grind and crush it, and sieve it through a 50-mesh sieve to obtain mixed animal manure particles. Weigh 5 kg of mixed animal manure particles, add 4.5 kg of water, mix and stir to wet them, and then evenly spray 40 g of the composite microbial agent obtained in Preparation Example 1 on the wetted mixed animal manure particles. After the spraying of the composite microbial agent is completed, place the mixed animal manure particles in a temperature environment of 30 °C, and adjust the ventilation flow rate with a blower to 0.4 m 3 / h, with ventilation fermentation once every 5 h for 30 min each time, and treat it 4 times a day. Before each ventilation fermentation, turn over the mixed animal manure particles to make them contact evenly, and ferment continuously for 6 days. After the fermentation is completed, take out the fermentation product to obtain fermented animal manure.

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

[0062] Example 5:

[0063] A preparation method of an organic fertilizer obtained by fermenting animal manure, specifically including the following process:

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

[0065] After taking 1 kg of corn straw and crushing it with a pulverizer, 18 kg of potassium hydroxide solution (mass concentration of 1.8%) was added and mixed. Then it was placed in a temperature environment of 90 °C and stirred at a speed of 300 r / min for 130 min. After the heating and stirring treatment, it was naturally cooled to room temperature, and then citric acid was added for adjustment until the pH reached neutral. At this time, 20 g of mixed cross-linking agent (composed of 10 g of sodium alginate and 10 g of glutaraldehyde) was added to the mixed solution in the neutral environment and heated to 80 °C, and stirred and reacted at a speed of 100 r / min for 1.8 h to obtain a cross-linked protective film solution. Take 2 kg of fermented animal feces and 2.8 kg of cross-linked protective film solution and mix and stir them, and then dry them to obtain organic fertilizer.

[0066] Example 6:

[0067] A preparation method of organic fertilizer obtained by fermenting animal feces specifically includes the following process:

[0068] Weigh 5 kg of cow dung, 5 kg of pig dung, 3 kg of chicken dung and 3 kg of sheep dung and mix them to form mixed animal feces. Then the mixed animal feces were placed in a hot air environment of 70 °C and dried for 20 h. After drying, it was ground and broken, and sieved through a 50-mesh sieve to obtain mixed animal feces particles. Weigh 5 kg of mixed animal feces particles, add 6.5 kg of water and mix and stir to wet them. Then 50 g of the composite bacterial agent obtained in Preparation Example 1 was evenly sprayed on the wetted mixed animal feces particles. After the spraying of the composite bacterial agent was completed, the mixed animal feces particles were placed in a temperature environment of 32 °C, and the ventilation flow rate was adjusted to 0.5 m 3 / h, with ventilation fermentation once every 5 h for 30 min each time, treated 4 times a day. Before each ventilation fermentation, the mixed animal feces particles were turned over to make them contact evenly, and fermented continuously for 7 days. After fermentation, the fermentation product was taken out to obtain fermented animal feces.

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

[0070] Example 7:

[0071] A preparation method of organic fertilizer obtained by fermenting animal feces specifically includes the following process:

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

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

[0074] Comparative Example 1:

[0075] A preparation method of organic fertilizer obtained by fermenting animal feces specifically includes the following process:

[0076] Replace the composite microbial agent in Example 7 with the composite microbial agent obtained in Preparation Example 2, and keep the other conditions the same as those in Example 7.

[0077] Comparative Example 2:

[0078] A method for preparing an organic fertilizer obtained by fermenting animal manure, specifically including the following process:

[0079] Replace the composite microbial agent in Example 7 with the composite microbial agent obtained in Preparation Example 3, and keep the other conditions the same as those in Example 7.

[0080] Comparative Example 3:

[0081] A method for preparing an organic fertilizer obtained by fermenting animal manure, specifically including the following process:

[0082] Increase the amount of water for wet-mixing animal manure particles in Example 7 to 10 kg, and keep the other conditions the same as those in Example 7.

[0083] Comparative Example 4:

[0084] A method for preparing an organic fertilizer obtained by fermenting animal manure, specifically including the following process:

[0085] Reduce the amount of potassium hydroxide solution in Example 7 to 5 kg, and keep the other conditions the same as those in Example 7.

[0086] Comparative Example 5:

[0087] A method for preparing an organic fertilizer obtained by fermenting animal manure, specifically including the following process:

[0088] Increase the amount of the mixed cross-linking agent in Example 7 to 50 g. It is found that the cross-linked protective film solution gels severely after cooling, which may be due to the overly dense cross-linked network structure resulting in poor fluidity of the solution and inability to achieve mixing with the fermented animal manure.

[0089] The mass fractions of organic matter and total nutrients (N + P2O5 + K2O) of the organic fertilizers obtained in Examples 1 - 7 and Comparative Examples 1 - 4 were measured according to the "Agricultural Industry Standard NY525 - 2021 of the People's Republic of China", and the results are shown in the following table:

[0090] Material source 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] It can be seen from the above results that:

[0092] (1) The composite microbial agent constructed by the present invention has good ability to ferment mixed animal feces, enabling the mixed animal feces to release more organic matter and improve the release of total nutrients such as nitrogen, phosphorus and potassium after being decomposed by the composite microbial agent of the present invention.

[0093] (2) It can be found from Comparative Examples 1 and 2 that although the replacement with other strains for fermentation has the fermentation ability, due to the different growth and reproduction environments and the structural composition of nutrients, the content of organic matter and total nutrients is low, not meeting the use requirements.

[0094] (3) It can be found from Comparative Example 3 that too high water content causes a relatively obvious decrease in the content of organic matter and total nutrients, which may be due to the inhibitory effect of the water content in this system on the fermentation of the strains.

[0095] (4) It can be seen from Comparative Example 4 that the content of organic matter and total nutrients performs well, but is slightly worse than that of Example 7. This may be because the use of potassium hydroxide solution is low, less cellulose is decomposed, resulting in a decrease in the ability of the strains to utilize the nutrients in the straw.

[0096] The organic fertilizers obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were tested for the nitrogen element static water release experiment according to "GBT23348-2009 Slow Release Fertilizer":

[0097] Test method: Place 10 g of organic fertilizer in 1000 mL of static water, and sample and measure the cumulative release rate of nitrogen element on the 3rd day, 10th day, 20th day and 30th day respectively. The results are as follows:

[0098]

[0099] It can be seen from the above results that:

[0100] (1) The organic fertilizer prepared by the present invention has a good slow release effect through the condensation cross-linked structure formed between sodium alginate, glutaraldehyde and the small molecule sugars after cellulose decomposition, and then wrapped 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, due to the changes in the environment such as nutrient components and water content of the strains in this environment, the fermentation efficiency of the composite microbial agent used in this environment is poor, the content of organic matter and total nutrients is low, and the finally released nitrogen element content is also low, not meeting the use requirements.

[0102] (3) It can be seen from Comparative Example 4 that the efficiency of decomposing cellulose with a lower amount of potassium hydroxide solution is low, resulting in less cellulose cross-linked with sodium alginate and glutaraldehyde, less formation of the slow release structure, and a poor slow 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 feces and the cross-linked protective film solution are mixed, stirred and dried in a mass ratio of 1:1-1.5 to obtain the organic fertilizer; The composite bacterial agent is composed of a mixture of Bacillus amyloliquefaciens, Candida lipolytica and Aspergillus carbonarius, wherein the mass ratio of Bacillus amyloliquefaciens: Candida lipolytica: Aspergillus carbonarius is 1:1:1; The mass ratio of the plant straw to the inorganic alkaline solution is 1:10-20; The mixed cross-linking agent is composed of sodium alginate and glutaraldehyde mixed in a mass ratio of 1:1; The mass ratio of the mixed cross-linking agent to the plant straw is 0.01-0.025:

1.

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 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 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.

4. 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.

5. 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.

6. 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 5.

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