Special organic fertilizer for bullet-type vegetables and preparation method of special organic fertilizer

Abstract

The invention provides a pill-type organic fertilizer special for vegetables. The pill-type organic fertilizer is prepared from the following raw materials in parts by weight: modified biochar, fermented livestock and poultry manure, plant source protein zymolyte, a complex microbial inoculant, a trace element supplement and a binder, and a method therefor; the complex microbial inoculants comprise actinomycetes, bacillus amyloliquefaciens and trichoderma harzianum; the trace element supplement comprises EDTA (Ethylene Diamine Tetraacetic Acid) chelated zinc, EDTA chelated iron and boric acid. Therefore, on one hand, the organic fertilizer can effectively improve the facility agriculture soil environment, adjust the soil acidity and alkalinity, reduce the salinization degree, promote balance and stability of microbial communities and restore and improve the ecological function of soil; on the other hand, the utilization rate of the fertilizer can be greatly improved, and the plant-source proteolysis provides a quick-acting nitrogen source to promote root development; the microelement supplement meets the requirements of vegetables on microelements; nutrients are balanced, vegetable stress resistance is enhanced, and photosynthetic efficiency is improved; and the binder enables the fertilizer to form uniform particles, is suitable for mechanical fertilization, and improves the fertilization efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural fertilizers, and in particular, to a bullet-shaped special organic fertilizer for vegetables and a preparation method thereof. Background Art

[0002] Facility agriculture realizes high-efficiency production through technologies such as greenhouse greenhouses. However, long-term application of chemical fertilizers has led to soil acidification (pH drops below 5.0), salinization (EC value up to 2.5 - 3.5 mS / cm), and microbial community imbalance, resulting in a continuous decline in vegetable yield and quality. Traditional organic fertilizers are mainly composed of livestock and poultry manure and straw, with a long nutrient release period (30 - 60 days), uneven particle morphology, and difficulty in adapting to the requirements of mechanized fertilization, leading to low fertilization efficiency. Although the granular organic fertilizers studied in recent years have improved the convenience of application, most of them are general-purpose and lack formula design for soil ecological restoration and precise nutrient supply of facility vegetables, resulting in soil ecological degradation and low nutrient utilization rate in facility agriculture. Literature shows that the efficient absorption of trace elements such as iron and zinc by facility vegetables and the improvement of soil enzyme activity are crucial for yield and stress resistance, but the existing fertilizers are insufficient in these aspects.

[0003] Therefore, there is an urgent need for a special organic fertilizer to solve the above problems. Summary of the Invention

[0004] The main object of the present invention is to provide a bullet-shaped special organic fertilizer for vegetables and a preparation method thereof, so as to at least solve the problems of soil ecological degradation and low nutrient utilization rate in existing facility agriculture.

[0005] To achieve the above object, the first aspect of the present invention provides a bullet-shaped special organic fertilizer for vegetables, comprising the following raw materials in parts by weight: 15 - 25 parts of modified biochar, 35 - 50 parts of fermented livestock and poultry manure, 10 - 20 parts of plant-derived protease hydrolysate, 1 - 3 parts of compound microbial agent, 0.5 - 2 parts of trace element supplement, and 3 - 6 parts of binder;

[0006] Among them, the plant-derived protease hydrolysate is prepared by enzymatically hydrolyzing soybean meal or rapeseed meal with neutral protease;

[0007] The compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens, and Trichoderma harzianum;

[0008] The trace element supplement includes EDTA chelated zinc, EDTA chelated iron, and boric acid.

[0009] Optionally, the modified biochar is prepared by high-temperature carbonization of rice husk or bamboo chips at 600 - 800 °C and then impregnating and modifying with phosphoric acid and potassium hydroxide solutions, with a specific surface area ≥ 300 m

[0009] ,

[0008] , ,

[0007] , , 2 , , ,

[0010] / g and a porosity ≥ 60%.

[0010] Optionally, the fermented livestock and poultry manure is prepared by anaerobic fermentation of sheep manure or chicken manure for 15 - 20 days followed by aerobic fermentation for 5 - 7 days, with an organic matter content of ≥55% and a moisture content of 15% - 25%.

[0011] Optionally, the free amino acid content in the plant - derived protease hydrolysate is ≥20%, and the molecular weight distribution of the peptide segments in the plant - derived protease hydrolysate is 500 - 2000 Da.

[0012] Optionally, the total viable count in the compound microbial agent is ≥2×10 8 CFU / g, and the mass ratio of the actinomycetes to the Trichoderma harzianum in the compound microbial agent is 2:1.

[0013] Optionally, in the trace element supplement, the mass ratio of the EDTA - chelated zinc, the EDTA - chelated iron, and the boric acid is 3:2:1.

[0014] Optionally, the binder is carboxymethyl cellulose or sodium alginate, and the particle hardness of the binder is ≥3.0 N.

[0015] The second aspect of the present invention provides a method for preparing a bullet - type special organic fertilizer for vegetables, which is applied to the bullet - type special organic fertilizer for vegetables of the present invention, and includes:

[0016] Step 1: Mix the fermented livestock and poultry manure, the modified biochar, and the plant - derived protease hydrolysate in proportion, then adjust the moisture to 50% - 60% and the carbon - nitrogen ratio to 20:1 - 25:1, and perform anaerobic fermentation for 10 - 15 days while controlling the temperature at 35 - 45°C to obtain a first treated product; wherein, the plant - derived protease hydrolysate is prepared by enzymatic hydrolysis of soybean meal or rapeseed meal with neutral protease;

[0017] Step 2: Transfer the first treated product to aerobic fermentation, add the compound microbial agent, ferment for 5 - 7 days, control the pile temperature at 50 - 60°C, and turn the pile once every 2 days to obtain a second treated product; wherein, the compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens, and Trichoderma harzianum;

[0018] Step 3: Dry the second treated product to a moisture content of ≤12%, then crush it to a particle size of 0.3 - 0.8 mm, then add the trace element supplement and the binder, and mix evenly to obtain a third treated product; wherein, the trace element supplement includes EDTA - chelated zinc, EDTA - chelated iron, and boric acid;

[0019] Step 4: Use a high - pressure granulator to make the third treated product into bullet - type particles with a diameter of 2 - 4 mm, and spray a slow - release film on the particle surface to obtain the organic fertilizer.

[0020] Optionally, the slow - release film is a starch - based slow - release film.

[0021] A bullet-shaped special organic fertilizer for vegetables according to the technical solution of the present invention comprises the following raw materials in parts by weight: 15-25 parts of modified biochar, 35-50 parts of fermented livestock and poultry manure, 10-20 parts of plant-derived protease hydrolysate, 1-3 parts of compound microbial agent, 0.5-2 parts of trace element supplement, and 3-6 parts of binder; wherein, the plant-derived protease hydrolysate is prepared by enzymatically hydrolyzing soybean meal or rapeseed meal with neutral protease; the compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens and Trichoderma harzianum; the trace element supplement includes EDTA chelated zinc, EDTA chelated iron and boric acid. Thus, on the one hand, the organic fertilizer in the present application can adjust the soil pH, reduce the salinization degree, promote the balance and stability of the microbial community, and restore and enhance the soil ecological function; on the other hand, it can greatly improve the fertilizer utilization rate. The plant-derived protease hydrolysate provides a quick-acting nitrogen source to promote root development, and is combined with the slow-acting nutrients of fermented livestock and poultry manure to achieve continuous supply; the trace element supplement meets the demand of vegetables for trace elements; the balanced nutrients enhance the stress resistance of vegetables and improve the photosynthetic efficiency; the binder makes the fertilizer into uniform granules, adapts to mechanized fertilization, improves the fertilization efficiency, reduces the labor intensity and cost; and it has strong pertinence, fits the characteristics of soil degradation in protected agriculture and the nutrient requirements of vegetables, and effectively solves the problem of insufficient application of existing fertilizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specification drawings forming a part of the present application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0023] Figure 1 is a flowchart of the preparation method of the bullet-shaped special organic fertilizer for vegetables provided by the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0025] The present application provides a bullet-shaped special organic fertilizer for vegetables, which comprises the following raw materials in parts by weight: 15-25 parts of modified biochar, 35-50 parts of fermented livestock and poultry manure, 10-20 parts of plant-derived protease hydrolysate, 1-3 parts of compound microbial agent, 0.5-2 parts of trace element supplement, and 3-6 parts of binder;

[0026] wherein, the plant-derived protease hydrolysate is prepared by enzymatically hydrolyzing soybean meal or rapeseed meal with neutral protease;

[0027] the compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens and Trichoderma harzianum;

[0028] the trace element supplement includes EDTA chelated zinc, EDTA chelated iron and boric acid.

[0029] Specifically, the organic fertilizer in this application is mainly applied to protected vegetables, which are vegetables grown using artificial facilities such as greenhouses and plastic tunnels. The modified biochar has a large specific surface area and a rich pore structure, and can adsorb hydrogen ions in the soil, thereby alleviating the problem of soil acidification and regulating the soil pH value. At the same time, the modified biochar can also adsorb salt ions in the soil solution and reduce the degree of soil salinization. In addition, the modified biochar can provide attachment sites and living spaces for soil microorganisms, promote the growth and reproduction of beneficial microorganisms, and help restore and maintain the balance of the soil microbial community. The fermented livestock and poultry manure contains rich organic matter and beneficial microorganisms. During the decomposition process of organic matter, the soil structure can be improved, the buffering capacity of the soil can be increased, and it helps to alleviate soil acidification. At the same time, the microbial metabolites produced during the fermentation of livestock and poultry manure can regulate the soil microbial community, promote the growth of beneficial microorganisms, and inhibit the reproduction of harmful microorganisms, playing a positive role in restoring the balance of the soil microbial community. Actinomycetes in the compound microbial inoculum can secrete substances such as antibiotics to inhibit the growth of harmful pathogens in the soil, and at the same time can also promote the decomposition and transformation of organic matter in the soil; Bacillus amyloliquefaciens has good phosphorus and potassium solubilizing abilities and can convert insoluble phosphorus and potassium in the soil into available forms that can be absorbed by crops, improving soil fertility; Trichoderma harzianum can prevent and control various plant diseases, and can promote the growth and development of plant roots, enhancing the stress resistance of plants. Among them, actinomycetes accelerate the mineralization of organic matter, Trichoderma harzianum inhibits soil-borne pathogens, the inhibition rate of Fusarium is 60%, and Bacillus amyloliquefaciens promotes the release of phosphorus, increasing the available phosphorus by 25%. The synergistic effect of the microbial inoculum helps to improve the structure of the soil microbial community and promote the balance and stability of the soil ecosystem. The plant-derived protease hydrolysate prepared by enzymatic hydrolysis of soybean meal or rapeseed meal with neutral protease contains rich small molecule nutrients such as amino acids and small peptides, and these small molecule nutrients can be quickly absorbed and utilized by crops. During the fertilizer preparation process, a binder is added to make the organic fertilizer disintegrate quickly after application, ensuring uniform nutrient release; in addition, various raw materials can be evenly mixed and formed into granules with regular shapes and uniform sizes, which is conducive to mechanized fertilization, improves the fertilization efficiency, and solves the problem of difficult fertilization caused by uneven particle morphology of traditional organic fertilizers.

[0030] Among them, the synergistic effect of modified biochar, fermented livestock and poultry manure, and plant-derived protease hydrolysate can provide comprehensive nutrient supply for protected vegetables. Modified biochar and fermented livestock and poultry manure provide rich organic matter and macronutrients, while plant-derived protease hydrolysate supplements available nutrients such as amino acids and small peptides, meeting the nutrient requirements of protected vegetables at different growth stages. It can also improve soil structure, increase soil fertility, and promote the growth and development of protected vegetables. The trace element supplement includes EDTA chelated zinc, EDTA chelated iron, and boric acid. EDTA chelated zinc and EDTA chelated iron have good water solubility and stability, can be efficiently absorbed and utilized by crops, meet the demand of protected vegetables for trace elements such as iron and zinc, and improve the yield and quality of vegetables. Boric acid is one of the essential trace elements for plant growth and development, and plays an important role in physiological processes such as flower bud differentiation and fruit development. Adding trace element supplements can solve the deficiency of existing fertilizers in optimizing trace elements, increase the absorption rate of zinc and iron by 30% - 40%, enhance the stress resistance and yield of protected vegetables, and improve the biological availability of trace elements.

[0031] Using the organic fertilizer in this application can, on the one hand, effectively improve the soil environment of protected agriculture, adjust soil pH, reduce the degree of salinization, promote the balance and stability of the microbial community, and restore and enhance soil ecological functions; on the other hand, it can greatly improve fertilizer utilization efficiency. The plant-derived protease hydrolysate provides an available nitrogen source, promotes root development, increasing root biomass by 15% - 20%, and coordinates with the slow-acting nutrients of fermented livestock and poultry manure to achieve continuous supply; the trace element supplement meets the demand of vegetables for trace elements; the balanced nutrient supply helps vegetable growth, enhances stress resistance, and improves photosynthetic efficiency; the binder makes the fertilizer into uniform granules, adapts to mechanized fertilization, improves fertilization efficiency, and reduces labor intensity and cost; and it has strong pertinence, conforms to the characteristics of soil degradation in protected agriculture and vegetable nutrient requirements, and effectively solves the problems of insufficient application of existing fertilizers.

[0032] In a possible implementation manner, the modified biochar is prepared by carbonizing rice husks or bamboo chips at a high temperature of 600 - 800 °C and then impregnating with phosphoric acid and potassium hydroxide solutions, with a specific surface area ≥ 300 m 2 / g and a porosity ≥ 60%.

[0033] Specifically, when the carbonization temperature is lower than 600 °C, components such as cellulose and hemicellulose in rice husks or bamboo chips are not decomposed sufficiently, and it is impossible to form a sufficient number and appropriately sized pore structure, resulting in the specific surface area of the modified biochar being difficult to reach ≥ 300 m 2 / g, its adsorption capacity is limited, making it difficult to effectively adsorb hydrogen ions in the soil to adjust the pH value, and its adsorption effect on salts will also be weak, thus unable to well improve the physical and chemical properties of the soil. At the same time, a porosity less than 60% results in insufficient attachment sites for soil microorganisms, which is not conducive to the growth and reproduction of the microbial community, and it is also difficult to restore and maintain the balance of the soil microbial community. When the carbonization temperature is higher than 800 °C, although the decomposition of the raw material may be more thorough, the excessively high temperature will cause a certain degree of shrinkage and densification of the structure of the biochar. This will instead reduce the porosity of the biochar, making it difficult to maintain at a level of ≥60%, thereby weakening its adsorption and retention capacity for nutrients and its carrying capacity for microorganisms. In addition, the excessively high temperature may also cause some beneficial functional groups to be damaged, affecting the adsorption performance of the biochar for heavy metal ions and its ability to regulate the soil pH value. Only under the high-temperature carbonization conditions of 600 - 800 °C can rice husks or bamboo chips fully undergo physical and chemical changes to form an appropriate pore structure, ensuring a specific surface area of ≥300 m 2 / g and a porosity of ≥60%, so as to enable the modified biochar to exert the best effects in improving soil acidification and salinization, promoting the balance of the microbial community, etc., and creating a good soil environment for the growth of protected vegetables. The modified biochar can increase the nutrient adsorption rate by 20% - 30%, reduce the soil EC value by 10% - 15%, and enhance the activity of the microbial agent as a microbial carrier.

[0034] In a possible implementation manner, the fermented livestock and poultry manure is obtained by anaerobic fermentation of sheep manure or chicken manure for 15 - 20 days followed by aerobic fermentation for 5 - 7 days, with an organic matter content of ≥55% and a moisture content of 15% - 25%.

[0035] Specifically, sheep manure and chicken manure are rich in macronutrients such as nitrogen, phosphorus, and potassium and various trace elements, which can provide balanced nutrients for the soil and meet the growth requirements of protected vegetables. The 15 - 20 days of anaerobic fermentation fully decomposes the organic matter, avoiding problems such as too hard texture, slow release of fertilizer efficiency, and root burning caused by the residue of undigested organic matter; the 5 - 7 days of aerobic fermentation further converts the nutrients, kills pathogenic bacteria and parasite eggs, and improves the safety and utilization rate of the fertilizer. After fermentation, the organic matter content is ≥55%, which can improve the soil structure, increase the water and fertilizer retention capacity, promote microbial activities, enhance the biological activity of the soil, be rich in active humus, and reduce the ammonia volatilization by 40% to reduce the loss of volatile nitrogen. The moisture content is controlled at 15% - 25%, which is not only convenient for storage, transportation, and fertilization operations, preventing dust and the growth of bacteria and molds, but also can ensure full mixing with the soil, realizing the slow release of nutrients and the effective absorption of vegetable roots, thereby creating a good soil environment for protected vegetables and improving the yield and quality.

[0036] In a possible embodiment, the free amino acid content in the plant-derived protein hydrolysate is ≥20%, and the molecular weight distribution of the peptide segments of the plant-derived protein hydrolysate is 500-2000 Da.

[0037] Specifically, the free amino acid content in plant-derived protein hydrolysates is ≥20%, which can quickly supplement fast-acting nitrogen sources for greenhouse vegetables, promote photosynthesis, protein synthesis and metabolism of vegetables, and enhance plant growth and stress resistance; at the same time, the molecular weight distribution of peptide segments is concentrated in 500-2000Da, which is easier to be directly absorbed and utilized by vegetable roots, and can also act as signal molecules to regulate plant growth gene expression and improve nutrient absorption efficiency.

[0038] In one possible embodiment, the total number of viable bacteria in the composite bacterial agent is ≥ 2×10 8 CFU / g, and the mass ratio of actinomycetes to Trichoderma harzianum in the composite bacterial agent is 2:1.

[0039] Specifically, the total number of viable cells ≥ 2 × 10 8 CFU / g, which ensures that a sufficient number of active microorganisms can colonize and play a role in the soil, quickly form a dominant bacterial community, effectively inhibit the growth and reproduction of harmful pathogens in the soil, improve the structure of soil microbial communities, and enhance the stability and buffering capacity of the soil ecosystem; at the same time, the mass ratio of actinomycetes to Trichoderma harzianum in the composite bacterial agent is 2:1, and the scientific ratio achieves functional complementarity. Actinomycetes can secrete antibiotic substances to inhibit pathogens, and Trichoderma harzianum can directly antagonize pathogenic fungi through heavy parasitism and promote plant root growth. The synergistic effect of the two can significantly improve the prevention and control effect of soil-borne diseases of facility vegetables.

[0040] In a possible embodiment, in the trace element supplement, the mass ratio of the EDTA-chelated zinc, the EDTA-chelated iron, and the boric acid is 3:2:1.

[0041] Specifically, EDTA-chelated zinc accounts for the largest proportion, because the demand for zinc is relatively high during the growth of greenhouse vegetables. As a component of multiple enzymes, zinc participates in key physiological processes such as auxin synthesis and protein metabolism. Adequate zinc supply can significantly promote the growth and development of vegetable plants and enhance photosynthesis efficiency. EDTA-chelated iron accounts for the second largest proportion. Iron is an essential element for chlorophyll synthesis and is crucial for maintaining the normal color and photosynthesis function of vegetable leaves. This ratio can meet the iron needs of vegetables and prevent the occurrence of iron-deficiency chlorosis. Boron plays a key regulatory role in the reproductive growth processes of vegetables, such as flower bud differentiation, fertilization and fruiting. Appropriate supplementation of boron can increase the fruit set rate and fruit quality of vegetables. The appropriate ratio accurately matches the trace element demand characteristics of greenhouse vegetables, achieves synergistic synergy among the elements, and significantly improves the absorption and utilization efficiency of trace elements, thereby promoting the healthy growth of vegetables and increasing yield and quality.

[0042] In a possible implementation manner, the binder is carboxymethyl cellulose or sodium alginate, and the particle hardness of the binder is ≥ 3.0 N.

[0043] Specifically, both carboxymethyl cellulose and sodium alginate are natural polymer materials, having good biocompatibility and film-forming properties, and can effectively bond components such as biochar, organic fertilizer, and microbial agents in the formula into uniform particles, avoiding powdering during transportation and storage. The particle hardness ≥ 3.0 N ensures that the fertilizer has excellent anti-crushing performance during mechanical fertilization, reduces the loss of active ingredients, and at the same time ensures the fertilization uniformity.

[0044] The present application also provides a method for preparing a bullet-type special organic fertilizer for vegetables, which is applied to the bullet-type special organic fertilizer for vegetables described in the present application, and includes:

[0045] Step 1: Mix fermented livestock and poultry manure, modified biochar, and plant-derived protease hydrolysate in proportion, then adjust the moisture to 50% - 60%, and the carbon-nitrogen ratio to 20:1 - 25:1, and perform anaerobic fermentation for 10 - 15 days, while controlling the temperature at 35 - 45 °C to obtain a first treatment product; wherein, the plant-derived protease hydrolysate is prepared by enzymatic hydrolysis of soybean meal or rapeseed meal with neutral protease;

[0046] Step 2: Transfer the first treatment product to aerobic fermentation, add a compound microbial agent, ferment for 5 - 7 days, control the pile temperature at 50 - 60 °C, and turn the pile once every 2 days to obtain a second treatment product; wherein, the compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens, and Trichoderma harzianum;

[0047] Step 3: Dry the second treatment product to a moisture content ≤ 12%, then crush it to a particle size of 0.3 - 0.8 mm, then add a trace element supplement and a binder, and mix evenly to obtain a third treatment product; wherein, the trace element supplement includes EDTA chelated zinc, EDTA chelated iron, and boric acid;

[0048] Step 4: Make the third treatment product into bullet-type particles with a diameter of 2 - 4 mm through a high-pressure granulator, and spray a slow-release film on the particle surface to obtain the organic fertilizer.

[0049] Specifically, as Figure 1As shown in the figure, in Step 1, the fermented livestock and poultry manure, modified biochar, and plant-derived protease hydrolysate are mixed in proportion, and then the moisture is adjusted to 50% - 60% and the carbon-nitrogen ratio to 20:1 - 25:1. Anaerobic fermentation is carried out at 35 - 45 °C for 10 - 15 days to obtain the first treatment product. Among them, the plant-derived protease hydrolysate is prepared by enzymatic hydrolysis of soybean meal or rapeseed meal with neutral protease and is rich in small molecular active peptides and amino acids. This step promotes the directional decomposition of organic matter in the raw materials through an anaerobic environment. The complex organic matter in the fermented livestock and poultry manure is gradually converted into humus and volatile fatty acids under the action of facultative anaerobic microorganisms. The modified biochar not only adsorbs harmful substances such as ammonia generated during the fermentation process with its rich pore structure, reducing nutrient loss, but also can react with heavy metal ions through surface functional groups such as complexation and precipitation, significantly reducing the activity and mobility of heavy metals such as cadmium and lead in the soil, avoiding their harm to crops and the environment, and at the same time providing an attachment carrier for microorganisms; the small peptides and amino acids in the plant-derived protease hydrolysate, as readily available nitrogen sources, can be quickly utilized by microorganisms. Adjusting the moisture and carbon-nitrogen ratio optimizes the metabolic environment of anaerobic microorganisms, accelerates the degradation of organic matter, and finally forms a semi-rotted material rich in active substances, laying a foundation for subsequent fermentation.

[0050] In Step 2, the first treatment product is transferred to the aerobic fermentation stage, and a composite microbial agent composed of actinomycetes, Bacillus amyloliquefaciens, and Trichoderma harzianum is added. The pile temperature is controlled at 50 - 60 °C, and the pile is turned over every 2 days. After 5 - 7 days of fermentation, the second treatment product is obtained. Among them, the composite microbial agent improves the fermentation efficiency through synergistic effects. In this stage, forced ventilation is used to supply oxygen to promote the rapid reproduction of aerobic microorganisms. The antibiotics secreted by actinomycetes can inhibit the reproduction of pathogenic bacteria. Bacillus amyloliquefaciens accelerates the mineralization and decomposition of organic matter by secreting extracellular enzymes. Trichoderma harzianum degrades refractory organic matter and promotes nutrient release through hyperparasitism. The high-temperature stage with the pile temperature maintained at 50 - 60 °C can effectively kill pathogenic bacteria, eggs, and weed seeds. The turning-over operation ensures that the material is evenly heated and oxygen is replenished, preventing local anaerobic decay. Finally, a fermented product with high maturity, strong nutrient activity, and harmlessness is formed, significantly improving the safety and fertilizer efficiency of the fertilizer.

[0051] Step 3: Dry the second processed material until the moisture content ≤ 12%, crush it to a particle size of 0.3 - 0.8 mm, then add trace element supplements such as zinc EDTA, iron EDTA, and boric acid, as well as a binder, and mix evenly to obtain the third processed material. Among them, the EDTA-chelated trace elements can enhance the nutrient activity. This step reduces the moisture content of the material and refines the particle size through drying and crushing, improving the operability of the subsequent granulation process; adding chelated trace elements can significantly improve the biological availability of nutrients. The EDTA chelation technology can prevent trace elements from being fixed in the soil and promote the direct absorption and utilization by crop roots; the binder enhances the mechanical strength after granulation, ensuring that the fertilizer is not easily broken during storage and transportation, and at the same time providing suitable physical properties for subsequent granulation, ultimately forming a uniformly dispersed mixed matrix and creating conditions for efficient granulation.

[0052] Step 4: Use a high-pressure granulator to form the third processed material into pellet-like particles with a diameter of 2 - 4 mm, and spray a slow-release film on the surface of the particles to finally obtain the finished organic fertilizer. Among them, the slow-release film can regulate the nutrient release period. This step makes the fertilizer particles regular in shape and uniform in size through the granulation process, meeting the requirements of mechanized fertilization. The pellet-like design can reduce the dust dispersion loss during fertilization; the high-pressure granulator improves the particle density and compressive strength through physical extrusion, ensuring that the fertilizer maintains a complete form during transportation and application; the surface spraying of the slow-release film uses a polymer material, and the slow-release of nutrients is achieved by controlling the pore size of the film, extending the fertilizer efficiency period, reducing nutrient leaching and volatilization losses, and at the same time protecting the activity of the compound microbial agent, realizing the synergistic effect of rapid supply of available nutrients and continuous release of long-acting nutrients, significantly improving the fertilizer utilization rate and soil improvement effect.

[0053] In this application, the plant-derived protease hydrolysate provides an available nitrogen source, and the EDTA-chelated trace elements prevent being fixed by the soil, greatly enhancing the nutrient activity and availability; in the fermentation process, anaerobic and aerobic fermentation are coordinated. The former promotes the directional decomposition of organic matter and reduces nutrient loss, and the latter relies on the compound microbial agent to kill harmful substances and degrade stubborn organic matter, producing a highly mature and harmless product; in terms of physical properties, drying and crushing improve the material characteristics for granulation, the binder enhances the particle strength, and the high-pressure granulator forms uniform pellet-like particles, reducing dust loss; the application of the slow-release film extends the fertilizer efficiency period and reduces nutrient leaching and volatilization; in addition, this preparation process can also promote soil improvement and ecological balance, increase soil organic matter, improve the structure, and stabilize the microbial community; ultimately achieving the comprehensive effects of improving the fertilizer utilization rate, increasing the yield and quality of vegetables, and enhancing the stress resistance of vegetables, providing strong support for the sustainable development of protected agriculture.

[0054] In a possible implementation manner, the slow-release film is a starch-based slow-release film.

[0055] Specifically, starch, as a natural degradable material, is widely sourced and low-cost, enabling the slow-release film to be gradually decomposed by microorganisms in the natural environment, and having good environmental friendliness. At the same time, the starch-based slow-release film can precisely control the pore size and permeability of the film by adjusting its composition and preparation process, thereby effectively regulating the release rate of fertilizer nutrients, prolonging the fertilizer efficiency period, reducing the leaching and volatilization losses of nutrients, and improving fertilizer utilization efficiency. In this application, corn flour is used as the starch-based material.

[0056] The solutions in this application are further illustrated by the following examples.

[0057] Step 1: Put 20 parts of modified biochar, 42 parts of fermented livestock and poultry manure, and 15 parts of plant-derived protease hydrolysate into a mixer in proportion and stir well. Adjust the moisture content of the mixture to 55% through an atomization system, and simultaneously add corn flour to adjust the carbon-nitrogen ratio to 22:1. Transfer the mixed materials into a closed fermentation tank and anaerobically ferment for 12 days at 40°C to obtain the first processed material.

[0058] Step 2: Transfer the first processed material that has completed anaerobic fermentation into a turning-type fermentation bin, and inoculate a compound microbial agent (total viable count ≥ 2×10 8 CFU / g) at a ratio of 1.5%. Ferment for 6 days under the condition of maintaining a heap temperature of 55°C, and mechanically turn the heap once every 2 days to ensure uniform oxygen supply. Actinomycetes secrete antibiotics to inhibit soil-borne pathogens at this stage, Bacillus amyloliquefaciens accelerates the mineralization of organic matter, and Trichoderma harzianum decomposes refractory organic matter through hyperparasitism. Control the moisture content ≤ 30% at the end of fermentation, and the material presents a dark brown color with a smell of soil.

[0059] Step 3: Use a double-roll dryer to dry the second processed material to a moisture content ≤ 12%, and refine it to a particle size of 0.3 - 0.8 mm through a hammer mill. Add trace element supplements (EDTA chelated zinc: EDTA chelated iron: boric acid = 3:2:1) and the binder carboxymethyl cellulose in proportion, and stir in a V-type mixer for 30 minutes to ensure uniform dispersion..

[0060] Step 4: Use a ring die granulator with a pore diameter of Φ2.5 - 4 mm to make bullet-shaped particles, and control the particle density in the range of 1.2 - 1.4 g / cm 3 by adjusting the ring die compression ratio. After the newly formed particles are dried to a moisture content ≤ 8% in a fluidized bed, they immediately enter the fluidized bed spraying system and are evenly sprayed with a starch-based slow-release film, with the film thickness controlled at 50 - 80 μm.

[0061] Yield and quality improvement: Field trials (in Jiangsu's greenhouse facilities in 2024) with lettuce and peppers as test materials showed that after applying the organic fertilizer in this solution, the yield increased by 18% - 30% compared to traditional organic fertilizers and by 12% - 20% compared to chemical fertilizers; the vitamin C content increased by 15% - 22%, and the soluble sugar content increased by 10% - 18%.

[0062] Soil ecological restoration: After 4 months of application, the soil urease activity increased by 20% - 25%, and the phosphatase activity increased by 15% - 20%; the soil salinization index (EC value) decreased from 2.8 mS / cm to 2.3 - 2.5 mS / cm; the proportion of soil aggregates (>0.25 mm) increased by 12% - 15%, and the organic carbon storage increased by 1.5% - 2.0%.

[0063] Nutrient release efficiency: Indoor simulation tests showed that the effective release rates of nitrogen, phosphorus, and potassium were 75%, 65%, and 85% respectively (within 20 days), which was more than 50% shorter than that of traditional organic fertilizers (40 - 50 days); the ammonia volatilization decreased by 35% - 45%.

[0064] Trace element absorption: The zinc and iron contents in plants increased by 35% and 30% respectively, the chlorophyll a / b content increased by 12% - 18%, and the photosynthetic rate increased by 15% - 20%.

[0065] Disease prevention and control: Greenhouse tests showed that Trichoderma harzianum had an inhibition rate of 60% - 70% against root rot (Fusarium), reducing the disease incidence from 15% to 5%.

[0066] Generally speaking, this application has the following beneficial effects:

[0067] Raw material innovation: Modified biochar and plant - derived protease hydrolysates were introduced for the first time to replace traditional straw and humic acid, significantly improving the nutrient adsorption and available nitrogen supply capacity, and breaking through the bottleneck of slow nutrient release in conventional organic fertilizers.

[0068] Bacterial agent optimization: A compound bacterial agent with actinomycetes and Trichoderma harzianum as the core was used. Aiming at the high incidence of pathogenic bacteria in greenhouse soil, it achieved the dual effects of nutrient activation and disease prevention and control, with obvious differences from existing microbial fertilizer formulas.

[0069] Process breakthrough: Anaerobic - aerobic alternating fermentation combined with slow - release coating technology accurately controls the nutrient release rate (15 - 25 days), with an efficiency 50% higher than that of traditional two - stage fermentation (30 - 45 days), and improves the stability of granule application.

[0070] Precise supply of trace elements: Through EDTA chelation technology, the biological availability of zinc and iron was significantly improved to meet the high - nutrition requirements of greenhouse vegetables, which is different from the conventional way of adding trace elements.

[0071] Precise nutrient supply: The synergistic effect of plant-derived protein hydrolysates and chelated trace elements meets the rapid growth needs of protected vegetables, and the nutrient utilization rate is increased by 20% - 30%.

[0072] Soil ecological optimization: Modified biochar and compound microbial agents enhance soil enzyme activity and microbial diversity, alleviate salinization and acidification, and the soil health index is increased by 15% - 20%.

[0073] Efficient application: 2 - 4mm pellet-type particles are adapted to precise fertilization equipment, the fertilization efficiency is increased by 30%, and the labor cost is reduced by 20% - 25%.

[0074] Green and safe: The fermentation process eliminates pathogenic bacteria (complies with NY / T525 - 2021), and modified biochar reduces soil salinity and heavy metals, among which the available states of cadmium and lead are reduced by 25% - 35%.

[0075] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A bullet-shaped special organic fertilizer for vegetables, characterized in that, It comprises the following raw materials in parts by weight: 15-25 parts of modified biochar, 35-50 parts of fermented livestock and poultry manure, 10-20 parts of plant-derived protease hydrolysate, 1-3 parts of compound microbial agent, 0.5-2 parts of trace element supplement, and 3-6 parts of binder; Among them, the plant-derived protease hydrolysate is prepared by enzymatically hydrolyzing soybean meal or rapeseed meal with neutral protease; The compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens, and Trichoderma harzianum; The trace element supplement includes EDTA chelated zinc, EDTA chelated iron, and boric acid.

2. The bullet-type special organic fertilizer for vegetables according to claim 1, characterized in that, The modified biochar is prepared by impregnating phosphoric acid and potassium hydroxide solutions after high-temperature carbonization of rice husks or bamboo chips at 600-800 °C, with a specific surface area ≥ 300 m 2 / g and a porosity ≥ 60%.

3. The bullet-type special organic fertilizer for vegetables according to claim 1, wherein The fermented livestock and poultry manure is obtained by anaerobic fermentation of sheep manure or chicken manure for 15-20 days and then aerobic fermentation for 5-7 days, with an organic matter content of ≥55% and a moisture content of 15%-25%.

4. The bullet-type special organic fertilizer for vegetables according to claim 1, characterized in that, The content of free amino acids in the plant-derived protease hydrolysate is ≥20%, and the molecular weight distribution of the peptide segments of the plant-derived protease hydrolysate is 500-2000 Da.

5. The bullet-type special organic fertilizer for vegetables according to claim 1, characterized in that, The total viable count in the compound microbial agent ≥ 2×10 8 CFU / g, and the mass ratio of the actinomycetes to the Trichoderma harzianum in the compound microbial agent is 2:

1.

6. The bullet-type special organic fertilizer for vegetables according to claim 1, characterized in that, In the trace element supplement, the mass ratio of EDTA chelated zinc, EDTA chelated iron, and boric acid is 3:2:

1.

7. The bullet-shaped special organic fertilizer for vegetables according to claim 1, wherein The binder is carboxymethyl cellulose or sodium alginate, and the particle hardness of the binder is ≥3.0 N.

8. A preparation method of a bullet-shaped special organic fertilizer for vegetables, characterized in that, Applied to the bullet-type special organic fertilizer for vegetables described in any one of claims 1-7, it includes: Step 1: Mix the fermented livestock and poultry manure, modified biochar, and plant-derived protease hydrolysate in proportion, then adjust the moisture to 50%-60% and the carbon-nitrogen ratio to 20:1-25:1, and carry out anaerobic fermentation for 10-15 days while controlling the temperature at 35-45°C to obtain the first treatment product; among them, the plant-derived protease hydrolysate is prepared by enzymatically hydrolyzing soybean meal or rapeseed meal with neutral protease; Step 2: Transfer the first treatment product to aerobic fermentation, add the compound microbial agent, and ferment for 5-7 days, controlling the pile temperature at 50-60°C and turning the pile once every 2 days to obtain the second treatment product; among them, the compound microbial agent includes actinomycetes, Bacillus amyloliquefaciens, and Trichoderma harzianum; Step 3: Dry the second treatment product to a moisture content of ≤12%, then crush it to a particle size of 0.3-0.8 mm, and then add the trace element supplement and the binder and mix evenly to obtain the third treatment product; among them, the trace element supplement includes EDTA chelated zinc, EDTA chelated iron, and boric acid; Step 4: Use a high-pressure granulator to make the third treatment product into bullet-type particles with a diameter of 2-4 mm, and spray a slow-release film on the surface of the particles to obtain the organic fertilizer.

9. The method for preparing the special organic fertilizer for bullet-shaped vegetables according to claim 8, characterized in that, The slow-release film is a starch-based slow-release film.

Images