Plant-derived bio-organic fertilizer and preparation method thereof

Abstract

The present application belongs to the technical field of organic fertilizer, and particularly relates to a plant source biological organic fertilizer and a preparation method thereof; wherein the plant source biological organic fertilizer comprises the following raw materials in parts by weight: 50-70 parts of mature organic matter base material, 8-15 parts of functional bacterial agent, 3-8 parts of additive, 2-5 parts of urea and 4-8 parts of diammonium phosphate; the additive prepared by the present application can specifically recognize and adsorb the cavity structure of heavy metal ions in the soil, realize in-situ passivation repair of the soil, and the polyphenol-iron complex film coated on the surface thereof can be in resonance with the bacteriostatic and growth promoting system of the main fertilizer, so as to broaden the bacteriostatic spectrum and strengthen the rhizosphere stress resistance effect. The functional bacterial agent constructed by the present application can adapt to the high-temperature composting stage, normal-temperature soil environment and low-temperature soil environment of the organic fertilizer, which not only guarantees efficient composting in the production process of the organic fertilizer, but also realizes the continuous biological activity of the fertilizer in the whole season and temperature range after being applied to the soil.

Description

Technical Field

[0001] This invention belongs to the field of organic fertilizer technology, specifically relating to a plant-derived bio-organic fertilizer and its preparation method. Background Technology

[0002] Plant-derived bio-organic fertilizers are prepared using natural organic materials such as agricultural and forestry waste and traditional Chinese medicine residues. They offer advantages such as soil improvement, rhizosphere microecology activation, crop growth promotion, and environmental friendliness, making them a core fertilizer category in current ecological agriculture, farmland restoration, and green planting. Compared to traditional chemical fertilizers, plant-derived bio-organic fertilizers can effectively increase soil organic matter content, optimize soil aggregate structure, and alleviate soil compaction and degradation. Simultaneously, they rely on functional microorganisms to activate soil nutrients and control soil-borne diseases, meeting the needs of green and sustainable agricultural development.

[0003] Currently, most commercially available plant-derived bio-organic fertilizers are prepared by simply mixing organic materials after basic composting with a single or small number of microbial strains. This process is relatively simplistic and suffers from several inherent technical shortcomings. Firstly, the microbial communities used in existing fertilizers are functionally limited and have poor temperature adaptability; most are single strains suitable for room temperature composting, making them unsuitable for the high-temperature composting process of organic fertilizers. Secondly, conventional microbial fertilizers lack a robust microbial survival and protection system, leaving functional microorganisms directly exposed in the organic fertilizer matrix, making them highly susceptible to inactivation during storage, transportation, and under stress from complex soil conditions such as salinity, drought, and contamination by other microorganisms. Thirdly, the nutrient release in existing bio-organic fertilizers is often uncontrolled, resulting in rapid nutrient loss in the early stages and insufficient nutrient supply in the later stages, leading to low fertilizer utilization and an inability to meet the nutrient requirements of crops throughout their entire growth cycle. Therefore, developing a composite plant-derived bio-organic fertilizer with full-temperature-range microbial community adaptability, long-lasting survival and slow-release properties, and multiple functions including soil improvement, disease prevention, and growth promotion is an urgent need in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a plant-derived bio-organic fertilizer and its preparation method; this invention achieves Cd control through the preparation of additives. 2+ Selective identification and efficient passivation; simultaneously employing Zn 2+ - A proanthocyanidin coordination network encapsulates a complex of thermophilic actinomycetes, Bacillus subtilis, and psychrogenic nitrogen-fixing bacteria, forming a pH-responsive rhizosphere-targeted release system. This solves the technical problems of low functional bacteria survival rate, poor selective passivation of heavy metal cadmium, and lack of rhizosphere-targeted release function in existing bio-organic fertilizers. The bio-organic fertilizer of this invention achieves a synergistic effect of functional bacteria protection, heavy metal passivation, and nutrient supply, significantly improving bacterial survival rate and selective heavy metal adsorption capacity.

[0005] To address the shortcomings of existing technologies, the present invention adopts the following technical solution: This invention provides a plant-derived bio-organic fertilizer, which comprises the following raw materials in parts by weight: 50-70 parts of decomposed organic matter substrate, 8-15 parts of functional microbial agent, 3-8 parts of additives, 2-5 parts of urea, 4-8 parts of diammonium phosphate, and 0.5-2 parts of wood ash. The additive comprises the following raw materials in parts by weight: methacrylic acid: ZnCl2: ethylene glycol dimethacrylate: gallic acid: FeCl3·6H2O: sodium alginate = 0.3-0.5:0.2:4:1:1.2-1.5:2; The method for preparing the additive includes the following steps: (a) Take methacrylic acid and ZnCl2, dissolve them in a mixed solvent, the mixed solvent is composed of methanol and deionized water in a volume ratio of 4:1, the volume ratio of ZnCl2 to the mixed solvent is 0.3-0.5g:20mL, stir magnetically at room temperature for 30 minutes, then add ethylene glycol dimethacrylate and azobisisobutyronitrile, bubble with nitrogen for 15 minutes to remove oxygen, add sodium alginate, stir to dissolve, heat to 60℃, polymerize under nitrogen protection for 24 hours, the system changes from clear to milky white, centrifuge, collect polymer microspheres, wash, shake for 30 minutes, vacuum dry for 12 hours to obtain polymer microspheres; (b) Weigh gallic acid and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 7.5-8.0 with 0.1 mol / L NaOH and filter the solution through a 0.22 μm filter membrane to obtain a gallic acid solution. Weigh FeCl3·6H2O and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 2.5-3.0 with 0.1 mol / L HCl and filter the solution through a 0.22 μm filter membrane to obtain a FeCl3 solution. (c) The polymer microspheres were immersed in gallic acid solution at a mass-volume ratio of 1 g:mL. The mixture was allowed to stand at room temperature for 15 minutes while being magnetically stirred at 100 rpm to assist diffusion. After filtration, the mixture was gently rinsed twice with deionized water. The product was then immersed in FeCl3 solution at a mass-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes. After filtration, the mixture was rinsed twice with deionized water. The alternating immersion process was repeated three times. The self-assembled product was then evenly spread on a stainless steel tray and freeze-dried under vacuum to obtain the additive.

[0006] The functional microbial agent comprises raw materials in the following ratio: corn stalks: FeCl3·6H2O: proanthocyanidins and ZnCl2: functional microbial suspension = 100g: 2.7g: 1-1.5g: 1.3g: 500mL; The preparation method of the functional microbial agent includes the following steps: (1) Take corn stalks, remove impurities such as mud and stones, wash them three times with deionized water, drain the water, place them in a forced-air drying oven, dry them at 80℃ for 24 hours until constant weight, crush them through a 60-mesh sieve to obtain straw powder, place the straw powder in a tube furnace, heat it to 350℃ at a heating rate of 5-10℃ / min under nitrogen atmosphere protection, keep it at constant temperature for 3 hours, and cool it naturally to room temperature to obtain primary biochar; (2) Weigh FeCl3·6H2O, prepare a FeCl3 solution with a concentration of 0.1 mol / L, add primary biochar to FeCl3 solution, the mass-volume ratio of primary biochar to FeCl3 solution is 1g:10mL, ultrasonically disperse for 30 minutes, then magnetically stir and impregnate for 12 hours, filter to collect solid, wash, dry at 105℃ for 12 hours, place the above dried product in a tube furnace, heat to 400℃ at 5℃ / min under nitrogen atmosphere, heat treat for 1 hour, and cool naturally to obtain iron modified biochar; (3) Take the prepared iron-modified biochar, dry it at 105℃ to constant weight, mix it with the functional bacterial suspension, place it in a shaker, shake and adsorb at 25℃ and 150rpm for 1.5 hours, filter it with sterile filter paper after adsorption, and collect the biochar loaded with bacteria. (4) Take proanthocyanidins and ZnCl2, and prepare proanthocyanidin solution and ZnCl2 solution respectively. Immerse the biochar loaded with bacteria in the proanthocyanidin solution. The mass-volume ratio of biochar loaded with bacteria to proanthocyanidin solution is 1g:10mL. Let it stand at room temperature for 15 minutes, and at the same time, use magnetic stirring at 100rpm to assist diffusion. Filter, rinse gently with deionized water twice, and then immerse the above product in ZnCl2 solution at a mass-volume ratio of 1g:10mL. Let it stand at room temperature for 15 minutes, filter, rinse with deionized water twice, and repeat the above alternating immersion operation 5 times to obtain the self-assembled product. Vacuum freeze to obtain the functional bacterial agent.

[0007] Furthermore, the preparation method of the proanthocyanidin solution is as follows: weigh the oligomeric proanthocyanidins and dissolve them in deionized water to prepare a solution with a mass-volume concentration of 1.0%. Adjust the pH to 7.5-8.0 with 0.1mol / L NaOH, filter and sterilize with a 0.22μm filter membrane to obtain the proanthocyanidin solution.

[0008] Furthermore, the culture process of thermophilic actinomycetes is as follows: The thermophilic actinomycetes are inoculated onto Gao's No. 1 agar medium, incubated statically at 55°C for 48 hours to activate them, and single colonies are picked and inoculated onto liquid medium, then cultured at 55°C and 180 rpm on a shaker for 48 hours to obtain a bacterial concentration ≥ 1 × 10⁻⁶. 8 Fermentation broth at CFU / mL was centrifuged at 4000 rpm for 15 minutes to collect the cells. The cells were then resuspended and washed twice with sterile physiological saline, and the cell concentration was adjusted to 5 × 10⁻⁶ cells with sterile water. 8 CFU / mL.

[0009] The culture process of Bacillus subtilis is as follows: Bacillus subtilis is inoculated onto LB agar medium and incubated statically at 37°C for 24 hours to activate it. A single colony is picked and inoculated onto LB liquid medium and cultured at 37°C and 200 rpm for 24 hours to obtain a bacterial concentration ≥1×10⁻⁶. 9 Fermentation broth at CFU / mL was centrifuged at 4000 rpm for 15 minutes to collect the cells. The cells were then resuspended and washed twice with sterile physiological saline, and the cell concentration was adjusted to 1×10⁻⁶ with sterile water. 10 CFU / mL.

[0010] The cultivation process for cryogenic nitrogen-fixing bacteria is as follows: Inoculate the cryogenic nitrogen-fixing bacteria onto Ashby nitrogen-free agar medium, incubate statically at 18°C ​​for 72 hours to activate them, then pick a single colony and inoculate it onto Ashby liquid medium, incubate at 18°C ​​and 150 rpm for 72 hours to obtain a bacterial concentration ≥ 5 × 10⁻⁶. 7 Fermentation broth at CFU / mL. Collect cells by centrifugation at 4000 rpm for 15 minutes, resuspend twice in sterile physiological saline, and then adjust the cell concentration to 2 × 10⁻⁶ with sterile water. 8 CFU / mL.

[0011] Furthermore, the preparation process of the functional bacterial suspension is as follows: thermophilic actinomycete suspension: Bacillus subtilis suspension: low-temperature nitrogen-fixing bacteria suspension = 1:2:1 by volume to obtain a mixed bacterial suspension. Trehalose and skim milk powder are added to the mixed bacterial suspension and gently stirred until completely dissolved to obtain the functional bacterial suspension.

[0012] Furthermore, the preparation method of the decomposed organic matter substrate is as follows: weigh corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, weathered coal humic acid, mix evenly, adjust the moisture content, inoculate with decomposing bacterial solution, and add cellulase and lignin peroxidase at the same time, pile up, and after decomposition, sun-dry or 40℃ hot air dry until the moisture content is ≤25%, crush and pass through a 60-mesh sieve to obtain the decomposed organic matter substrate; The mass ratio of corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, humic acid, cellulase, and lignin peroxidase is 10-15:3:2:2:1:2:0.02:0.01.

[0013] This invention also provides a method for preparing plant-derived bio-organic fertilizer, specifically including the following steps: S1. Add the decomposed organic substrate, additives, and wood ash to a double-helix conical mixer and mix for 15 minutes at 30 rpm. Add the functional microbial agent and continue mixing for 10 minutes. Then, pulverize urea, diammonium phosphate, and potassium sulfate separately through an 80-mesh sieve and slowly add them to the mixer. Continue mixing for 10 minutes until the color is uniform to obtain the mixed matrix. S2, the mixed substrate is granulated using a disc granulator, sieved, and packaged to obtain plant-derived bio-organic fertilizer.

[0014] Furthermore, the composting bacterial solution is at least one of Bacillus licheniformis, Bacillus subtilis, and Bacillus thermophilus.

[0015] Compared with the prior art, the technical effects achieved by the present invention are as follows: This invention utilizes a multi-level functional system coupling and combination to organically integrate plant-derived decomposed organic matter substrates, additives, and functional microbial agents, forming a multi-dimensional closed-loop empowerment system. The additives prepared in this invention are deeply coupled and complementary to the overall fertilizer efficiency system, endowing the fertilizer with novel soil remediation and nutrient retention functions. The polymer microspheres possess a specific ion recognition and adsorption cavity structure, which can target and solidify heavy metal ions in the soil, achieving in-situ passivation and remediation. The polyphenol-iron complex membrane coated on its surface can synergize with the antibacterial and growth-promoting systems of the main fertilizer, broadening the antibacterial spectrum and enhancing rhizosphere stress resistance. Furthermore, this additive can assist in adsorbing and fixing free nutrients in the soil, reducing nutrient leaching loss, and achieving synergistic effects of soil improvement, remediation, disease prevention, and growth promotion. This invention establishes a deeply compatible coupling relationship between functional microbial agents and plant-derived fermentation substrates. Thermophilic actinomycetes are well-suited to the high-temperature composting stage of organic fertilizers, directionally degrading lignin and cellulose in the substrate, breaking down the dense structure of plant fibers, and promoting the full composting of plant-derived raw materials such as straw. Mesophilic Bacillus subtilis can stably colonize in soil environments at room temperature, continuously exerting its effects of promoting growth, solubilizing phosphorus and potassium, and inhibiting harmful bacteria. Low-temperature nitrogen-fixing bacteria are adaptable to low-temperature soil environments, filling the gap in soil microbial activity during low-temperature periods. This ensures efficient composting during organic fertilizer production and achieves continuous biological activity of the fertilizer throughout the year and across all temperature ranges after application to the soil. The treatment and preparation of functional bacterial suspensions effectively enhances the stability and soil compatibility of functional microorganisms. Combined with a polyphenol-iron layered self-assembled protective film and an inner bacterial support system, a double-layered protective slow-release structure is formed, achieving long-lasting bacterial stability and gradient slow-release synergistic effects. After the plant-derived substrate has decomposed, it can sustainably release organic matter, natural active flavonoids, polysaccharides and trace elements, providing a mild carbon source and nutrient environment for the functional microorganisms to grow in the soil for a long time, helping the microorganisms to reproduce and metabolize continuously in the soil; at the same time, various modified functional components can revitalize the soil, optimize the soil aggregate structure, and improve the conversion and utilization efficiency of plant-derived organic matter, ultimately achieving multiple synergistic effects of soil improvement and crop growth promotion and quality improvement. Attached Figure Description

[0016] Figure 1 Here is a SEM image of the additive prepared according to the present invention; Figure 2 The plant-derived bio-organic fertilizer prepared according to this invention is effective against Cd. 2+ The amount of adsorption. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of the present invention and to make the above-mentioned features, objectives, and advantages of the present invention clearer and easier to understand, the present invention will be further described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0019] Unless otherwise specified, all methods described in the following embodiments are conventional. Unless otherwise specified, all materials used in the following embodiments are new materials purchased from the market.

[0020] Example 1: This example provides a plant-derived bio-organic fertilizer, which includes the following raw materials in parts by weight: 50 parts of decomposed organic matter substrate, 8 parts of functional microbial agent, 3 parts of additives, 2 parts of urea, 4 parts of diammonium phosphate, and 0.5 parts of wood ash. The additive comprises the following raw materials in parts by weight: methacrylic acid: ZnCl2: ethylene glycol dimethacrylate: gallic acid: FeCl3·6H2O: sodium alginate = 0.3:0.2:4:1:1.2:2; The method for preparing the additive includes the following steps: (a) Take methacrylic acid and ZnCl2, dissolve them in a mixed solvent consisting of methanol and deionized water in a volume ratio of 4:1, and use ZnCl2 in a volume ratio of 0.3g:20mL. Stir magnetically at room temperature for 30 minutes, then add ethylene glycol dimethacrylate and azobisisobutyronitrile, bubble with nitrogen for 15 minutes to remove oxygen, add sodium alginate, stir at 500rpm to dissolve, heat to 60℃, polymerize under nitrogen protection for 24 hours, the system changes from clear to milky white, centrifuge at 8000rpm for 10 minutes, collect, wash 3 times with a mixed solvent of methanol and acetic acid in a volume ratio of 9:1, 50mL each time, shake for 30 minutes to remove the template, wash 3 times with methanol to remove residual acetic acid, and vacuum dry at 50℃ for 12 hours to obtain polymer microspheres; (b) Weigh gallic acid and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 7.5 with 0.1 mol / L NaOH and filter the solution through a 0.22 μm filter membrane to obtain a gallic acid solution. Weigh FeCl3·6H2O and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 2.5 with 0.1 mol / L HCl and filter the solution through a 0.22 μm filter membrane to obtain a FeCl3 solution. (c) The polymer microspheres were immersed in gallic acid solution at a mass-to-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes while being magnetically stirred at 100 rpm to assist diffusion. After filtration, the mixture was gently rinsed twice with deionized water. The product was then immersed in FeCl3 solution at a mass-to-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes. After filtration, the mixture was rinsed twice with deionized water. The alternating immersion process was repeated three times to obtain a self-assembled product. The self-assembled product was evenly spread on a stainless steel tray with a thickness of 2 cm and placed in a vacuum freeze dryer. The product was pre-frozen at -40°C for 3 hours, dried once at -20°C and a vacuum of 18 Pa for 24 hours, and dried again at 25°C and a vacuum of 8 Pa for 12 hours to obtain the additive.

[0021] The functional microbial agent comprises raw materials in the following ratio: corn stalks: FeCl3·6H2O: proanthocyanidins and ZnCl2: functional microbial suspension = 100g: 2.7g: 1g: 1.3g: 500mL; The preparation method of the functional microbial agent includes the following steps: (1) Take corn stalks, remove impurities such as mud and stones, wash them three times with deionized water, drain the water, place them in a forced-air drying oven, dry them at 80℃ for 24 hours until constant weight, pulverize them through a 60-mesh sieve to obtain straw powder, place the straw powder in a tube furnace, heat it to 350℃ at a heating rate of 5℃ / min under nitrogen atmosphere protection (gas flow rate 100 mL / min), keep it at constant temperature for pyrolysis for 3 hours, and cool it naturally to room temperature to obtain primary biochar; (2) Weigh FeCl3·6H2O and prepare a FeCl3 solution with a concentration of 0.1 mol / L. Add the primary biochar to the FeCl3 solution. The mass-volume ratio of the primary biochar to the FeCl3 solution is 1 g: 10 mL. Disperse the biochar by ultrasonication for 30 minutes at a power of 200 W and a frequency of 40 kHz. Stir the biochar magnetically at 200 rpm for 12 hours at room temperature. Filter and collect the solid. Wash the solid with deionized water until the filtrate is colorless. The filtrate should not show any red color when tested with 0.1 mol / L KSCN solution. Dry the biochar at 105 °C for 12 hours. Place the dried product in a tube furnace and heat it to 400 °C at 5 °C / min under a nitrogen atmosphere (100 mL / min). Heat the product for 1 hour and allow it to cool naturally to obtain iron-modified biochar. (3) Take the prepared iron-modified biochar, dry it at 105℃ to constant weight, mix it with the functional bacterial suspension, place it in a shaker, shake and adsorb at 25℃ and 150rpm for 1.5 hours, filter it with sterile filter paper after adsorption, and collect the biochar loaded with bacteria. (4) Take proanthocyanidins and ZnCl2, and prepare proanthocyanidin solution and ZnCl2 solution respectively. Immerse the biochar loaded with bacteria in the proanthocyanidin solution with a mass-volume ratio of 1g:10mL. Let it stand at room temperature for 15 minutes, and at the same time, use magnetic stirring at 100rpm to assist diffusion. Filter and rinse twice with deionized water. Then immerse the above product in ZnCl2 solution with a mass-volume ratio of 1g:10mL. Let it stand at room temperature for 15 minutes, filter, and rinse twice with deionized water. Repeat the above alternating immersion operation 5 times to obtain the self-assembled product. Spread the self-assembled product evenly on a stainless steel tray with a thickness of 2cm. Place it in a vacuum freeze dryer, pre-freeze at -40℃ for 3 hours, dry at -20℃ and vacuum degree 18Pa for 24 hours, and dry at 25℃ and vacuum degree 8Pa for 12 hours to obtain the functional bacterial agent.

[0022] The preparation process of proanthocyanidin solution is as follows: Weigh 1.0g of oligomeric proanthocyanidins and dissolve them in 100mL of deionized water to prepare a solution with a mass-volume concentration of 1.0%. Adjust the pH to 7.5 with 0.1mol / L NaOH and filter it through a 0.22μm filter membrane to remove bacteria, thus obtaining the proanthocyanidin solution.

[0023] The cultivation process of thermophilic actinomycetes is as follows: The thermophilic actinomycetes are inoculated onto Gao's No. 1 agar medium, incubated statically at 55°C for 48 hours to activate them, and single colonies are picked and inoculated onto liquid medium, then incubated at 55°C and 180 rpm on a shaker for 48 hours to obtain a bacterial concentration of 1×10⁻⁶. 8 Fermentation broth at CFU / mL was centrifuged at 4000 rpm for 15 minutes to collect the cells. The cells were then resuspended and washed twice with sterile physiological saline, and the cell concentration was adjusted to 5 × 10⁻⁶ cells with sterile water. 8 CFU / mL.

[0024] The culture process of Bacillus subtilis is as follows: Bacillus subtilis is inoculated onto LB agar medium and incubated statically at 37°C for 24 hours to activate it. A single colony is picked and inoculated onto LB liquid medium and cultured at 37°C and 200 rpm for 24 hours to obtain a bacterial concentration of 1×10⁻⁶. 9 Fermentation broth at CFU / mL was centrifuged at 4000 rpm for 15 minutes to collect the cells. The cells were then resuspended and washed twice with sterile physiological saline, and the cell concentration was adjusted to 1×10⁻⁶ with sterile water. 10 CFU / mL.

[0025] The cultivation process of cryogenic nitrogen-fixing bacteria is as follows: Cultured nitrogen-fixing bacteria are inoculated onto Ashby nitrogen-free agar medium and incubated statically at 18°C ​​for 72 hours to activate them. Single colonies are then picked and inoculated onto Ashby liquid medium and incubated at 18°C ​​and 150 rpm for 72 hours to obtain a bacterial concentration of 5 × 10⁻⁶. 7 Fermentation broth at CFU / mL. Collect cells by centrifugation at 4000 rpm for 15 minutes, resuspend twice in sterile physiological saline, and then adjust the cell concentration to 2 × 10⁻⁶ with sterile water. 8 CFU / mL.

[0026] The preparation process of the functional bacterial suspension is as follows: thermophilic actinomycete suspension: Bacillus subtilis suspension: low-temperature nitrogen-fixing bacteria suspension are mixed in a volume ratio of 1:2:1 to obtain a mixed bacterial suspension. Trehalose is added to the mixed bacterial suspension to make the mass-volume concentration of trehalose in the mixed bacterial suspension 8%. At the same time, skim milk powder is added to make the mass-volume concentration of skim milk powder in the mixed bacterial suspension 2%. The mixture is gently stirred until completely dissolved to obtain the functional bacterial suspension.

[0027] The preparation method of the organic substrate is as follows: Weigh corn stalks, soybean meal, rice husks, astragalus root residue, γ-polyglutamic acid, and weathered coal humic acid, mix them evenly, adjust the moisture content to 60%, adjust the C / N ratio to 25:1, inoculate with Bacillus licheniformis suspension at an inoculation amount of 5% (w / w), and simultaneously add cellulase and lignin peroxidase. Build a pile in a windrow style, 1.2m high and 2m wide at the bottom, with ventilation pipes laid at the bottom, providing a ventilation volume of 0.2 m³ / h. 3 / (min·m 3 The fermentation cycle is 15 days: Turn the pile once a day from day 0 to 3 (medium temperature period, 25℃); turn the pile once every 2 days from day 4 to 10 (high temperature period, 55℃); turn the pile once every 3 days from day 11 to 20 (cooling and decomposition period, 35℃). After decomposition, dry the pile in the sun until the moisture content is 25%, then crush it through a 60-mesh sieve to obtain the decomposed organic substrate. The mass ratio of corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, humic acid, cellulase, and lignin peroxidase is 10:3:2:2:1:2:0.02:0.01.

[0028] This embodiment also provides a method for preparing plant-derived bio-organic fertilizer, specifically including the following steps: S1. Add the decomposed organic substrate, additives, and wood ash to a double-helix conical mixer and mix for 15 minutes at 30 rpm. Add the functional microbial agent and continue mixing for 10 minutes. Then, pulverize urea, diammonium phosphate, and potassium sulfate separately through an 80-mesh sieve and slowly add them to the mixer. Continue mixing for 10 minutes until the color is uniform to obtain the mixed matrix. S2. The mixed matrix was granulated using a disc granulator, with the material moisture content controlled at 25%, the disc inclination angle at 45°, the rotation speed at 15 rpm, and the granulation time at 10 minutes. The particle size was controlled at 2 mm. Fluidized bed drying was then used, with an inlet air temperature of 45°C, until the moisture content reached 15%. The granules were sieved, with a 6 mm sieve on the upper layer and a 1 mm sieve on the lower layer. 1 mm particles were taken as the finished product, vacuum-packed in aluminum foil bags, and stored at 4°C in the dark to obtain plant-derived bio-organic fertilizer.

[0029] Example 2: This example provides a plant-derived bio-organic fertilizer, which includes the following raw materials in parts by weight: 60 parts of decomposed organic matter substrate, 10 parts of functional microbial agent, 5 parts of additives, 3 parts of urea, 5 parts of diammonium phosphate, and 1 part of wood ash. The additive comprises the following raw materials in parts by weight: methacrylic acid: ZnCl2: ethylene glycol dimethacrylate: gallic acid: FeCl3·6H2O: sodium alginate = 0.4:0.2:4:1:1.5:2; The method for preparing the additive includes the following steps: (a) Take methacrylic acid and ZnCl2, dissolve them in a mixed solvent consisting of methanol and deionized water in a volume ratio of 4:1, and use ZnCl2 in a volume ratio of 0.4g:20mL. Stir magnetically at room temperature for 30 minutes, then add ethylene glycol dimethacrylate and azobisisobutyronitrile, bubble with nitrogen for 15 minutes to remove oxygen, add sodium alginate, stir at 500rpm to dissolve, heat to 60℃, and polymerize under nitrogen protection for 24 hours. The system changes from clear to milky white. Centrifuge at 8000rpm for 10 minutes, collect the polymer microspheres, wash 3 times with a mixed solvent of methanol and acetic acid in a volume ratio of 9:1, 50mL each time, shake for 30 minutes to remove the template, wash 3 times with methanol to remove residual acetic acid, and vacuum dry at 50℃ for 12 hours to obtain polymer microspheres; (b) Weigh gallic acid and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 8.0 with 0.1 mol / L NaOH and filter the solution through a 0.22 μm filter membrane to obtain a gallic acid solution. Weigh FeCl3·6H2O and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 3.0 with 0.1 mol / L HCl and filter the solution through a 0.22 μm filter membrane to obtain a FeCl3 solution. (c) The polymer microspheres were immersed in gallic acid solution at a mass-to-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes while being magnetically stirred at 100 rpm to assist diffusion. After filtration, the mixture was gently rinsed twice with deionized water. The product was then immersed in FeCl3 solution at a mass-to-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes. After filtration, the mixture was rinsed twice with deionized water. The alternating immersion process was repeated three times to obtain a self-assembled product. The self-assembled product was evenly spread on a stainless steel tray with a thickness not exceeding 2 cm. The tray was placed in a vacuum freeze dryer and pre-frozen at -40°C for 3 hours. It was then dried once at -20°C and a vacuum of 10 Pa for 24 hours, and then dried again at 25°C and a vacuum of 5 Pa for 12 hours to obtain the additive.

[0030] The functional microbial agent comprises raw materials in the following ratio: corn stalks: FeCl3·6H2O: proanthocyanidins and ZnCl2: functional microbial suspension = 100g: 2.7g: 1.2g: 1.3g: 500mL; The preparation method of the functional microbial agent includes the following steps: (1) Take corn stalks, remove impurities such as mud and stones, wash them three times with deionized water, drain the water, place them in a forced-air drying oven, dry them at 80℃ for 24 hours until constant weight, crush them through a 60-mesh sieve to obtain straw powder, place the straw powder in a tube furnace, heat it to 350℃ at a heating rate of 8℃ / min under nitrogen atmosphere protection (gas flow rate 150 mL / min), keep it at constant temperature for pyrolysis for 3 hours, and cool it naturally to room temperature to obtain primary biochar; (2) Weigh FeCl3·6H2O and prepare a FeCl3 solution with a concentration of 0.1 mol / L. Add the primary biochar to the FeCl3 solution. The mass-volume ratio of primary biochar to FeCl3 solution is 1g:10mL. Disperse the mixture by ultrasonication for 30 minutes at a power of 200W and a frequency of 40kHz. Stir the mixture magnetically at 200rpm for 12 hours at room temperature. Filter to collect the solid. Wash the solid with deionized water until the filtrate is colorless. Dry the solid at 105℃ for 12 hours. Place the dried product in a tube furnace and heat it to 400℃ at 5℃ / min under a nitrogen atmosphere (150mL / min). Heat the product for 1 hour and allow it to cool naturally to obtain iron-modified biochar. (3) Take the prepared iron-modified biochar, dry it at 105℃ to constant weight, mix it with the functional bacterial suspension, place it in a shaker, shake and adsorb at 25℃ and 150rpm for 1.5 hours, filter it with sterile filter paper after adsorption, and collect the biochar loaded with bacteria. (4) Take proanthocyanidins and ZnCl2, and prepare proanthocyanidin solution and ZnCl2 solution respectively. Immerse the biochar loaded with bacteria in the proanthocyanidin solution with a mass-volume ratio of 1g:10mL. Let it stand at room temperature for 15 minutes, and at the same time, use magnetic stirring at 100rpm to assist diffusion. Filter and rinse twice with deionized water. Then immerse the above product in ZnCl2 solution with a mass-volume ratio of 1g:10mL. Let it stand at room temperature for 15 minutes, filter, and rinse twice with deionized water. Repeat the above alternating immersion operation 5 times to obtain the self-assembled product. Spread the self-assembled product evenly on a stainless steel tray with a thickness of no more than 2cm. Place it in a vacuum freeze dryer, pre-freeze at -40℃ for 3 hours, dry once at -20℃ and vacuum degree 10Pa for 24 hours, and dry twice at 25℃ and vacuum degree 5Pa for 12 hours to obtain the functional bacterial agent.

[0031] The method for preparing the decomposed organic substrate is as follows: Weigh out corn stalks, soybean meal, rice husks, astragalus root residue, γ-polyglutamic acid, and weathered coal humic acid, mix them thoroughly, adjust the moisture content to 65%, and adjust the C / N ratio to 30:1. Inoculate with Bacillus subtilis suspension at a rate of 5% (w / w), and simultaneously add 20g of cellulase and 10g of lignin peroxidase. Build a windrow pile, 1.5m high and 2.5m wide at the base, with ventilation pipes at the bottom, providing ventilation of 0.3 m³ / h. 3 / (min·m 3 The fermentation cycle is 20 days: Turn the pile once a day from day 0 to 3 (medium temperature period, 30℃); turn the pile once every 2 days from day 4 to 10 (high temperature period, 60℃); turn the pile once every 3 days from day 11 to 20 (cooling and decomposition period, 30℃). After decomposition, dry the pile in the sun until the moisture content is 18%, then crush it through a 60-mesh sieve to obtain the decomposed organic substrate. The mass ratio of corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, humic acid, cellulase, and lignin peroxidase is 12:3:2:2:1:2:0.02:0.01.

[0032] This embodiment also provides a method for preparing plant-derived bio-organic fertilizer, specifically including the following steps: S1. Add the decomposed organic substrate, additives, and wood ash to a double-helix conical mixer and mix for 15 minutes at 30 rpm. Add the functional microbial agent and continue mixing for 10 minutes. Then, pulverize urea, diammonium phosphate, and potassium sulfate separately through an 80-mesh sieve and slowly add them to the mixer. Continue mixing for 10 minutes until the color is uniform to obtain the mixed matrix. S2. The mixed matrix was granulated using a disc granulator, with the material moisture content controlled at 30%, the disc inclination angle at 50°, the rotation speed at 20 rpm, and the granulation time at 15 minutes. The particle size was controlled at 3 mm. Fluidized bed drying was then used, with an inlet air temperature of 40°C, until the moisture content reached 10%. The granules were sieved, with a 6 mm sieve on the upper layer and a 1 mm sieve on the lower layer. The 3 mm granules were taken as the finished product, vacuum-packed in aluminum foil bags, and stored at 5°C in the dark to obtain plant-derived bio-organic fertilizer.

[0033] Example 3: This example provides a plant-derived bio-organic fertilizer, which includes the following raw materials in parts by weight: 70 parts of decomposed organic matter substrate, 15 parts of functional microbial agent, 8 parts of additives, 5 parts of urea, 8 parts of diammonium phosphate, and 2 parts of wood ash. The additive comprises the following raw materials in parts by weight: methacrylic acid: ZnCl2: ethylene glycol dimethacrylate: gallic acid: FeCl3·6H2O: sodium alginate = 0.5:0.2:4:1:1.5:2; The method for preparing the additive includes the following steps: (a) Take methacrylic acid and ZnCl2, dissolve them in a mixed solvent consisting of methanol and deionized water in a volume ratio of 4:1, and use ZnCl2 in a volume ratio of 0.5g:20mL. Stir magnetically at room temperature for 30 minutes, then add ethylene glycol dimethacrylate and azobisisobutyronitrile, bubble with nitrogen for 15 minutes to remove oxygen, add sodium alginate, stir at 500rpm to dissolve, heat to 60℃, and polymerize under nitrogen protection for 24 hours. The system changes from clear to milky white. Centrifuge at 8000rpm for 10 minutes, collect the polymer microspheres, wash 3 times with a mixed solvent of methanol and acetic acid in a volume ratio of 9:1, 50mL each time, shake for 30 minutes to remove the template, wash 3 times with methanol to remove residual acetic acid, and vacuum dry at 50℃ for 12 hours to obtain polymer microspheres; (b) Weigh gallic acid and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 8.0 with 0.1 mol / L NaOH and filter the solution through a 0.22 μm filter membrane to obtain a gallic acid solution. Weigh FeCl3·6H2O and dissolve it in deionized water at a ratio of 1 g to 100 mL. Adjust the pH to 3.0 with 0.1 mol / L HCl and filter the solution through a 0.22 μm filter membrane to obtain a FeCl3 solution. (c) The polymer microspheres were immersed in gallic acid solution at a mass-to-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes while being magnetically stirred at 100 rpm to assist diffusion. After filtration, the mixture was gently rinsed twice with deionized water. The product was then immersed in FeCl3 solution at a mass-to-volume ratio of 1 g:10 mL. The mixture was allowed to stand at room temperature for 15 minutes. After filtration, the mixture was rinsed twice with deionized water. The alternating immersion process was repeated three times to obtain a self-assembled product. The self-assembled product was evenly spread on a stainless steel tray with a thickness not exceeding 2 cm. The tray was placed in a vacuum freeze dryer and pre-frozen at -40°C for 3 hours. It was then dried once at -20°C and a vacuum of 10 Pa for 24 hours, and then dried again at 25°C and a vacuum of 5 Pa for 12 hours to obtain the additive.

[0034] The functional microbial agent comprises raw materials in the following ratio: corn stalk: FeCl3·6H2O: proanthocyanidins and ZnCl2: functional microbial suspension = 100g: 2.7g: 1.5g: 1.3g: 500mL; The preparation method of the functional microbial agent includes the following steps: (1) Take corn stalks, remove impurities such as mud and stones, wash them three times with deionized water, drain the water, place them in a forced-air drying oven, dry them at 80℃ for 24 hours until constant weight, crush them through a 60-mesh sieve to obtain straw powder, place the straw powder in a tube furnace, heat it to 350℃ at a heating rate of 10℃ / min under nitrogen atmosphere protection (gas flow rate 200 mL / min), keep it at constant temperature for pyrolysis for 3 hours, and cool it naturally to room temperature to obtain primary biochar; (2) Weigh FeCl3·6H2O and prepare a FeCl3 solution with a concentration of 0.1 mol / L. Add the primary biochar to the FeCl3 solution. The mass-volume ratio of primary biochar to FeCl3 solution is 1g:10mL. Disperse the mixture by ultrasonication for 30 minutes at a power of 200W and a frequency of 40kHz. Stir the mixture magnetically at 200rpm for 12 hours at room temperature. Filter to collect the solid. Wash the solid with deionized water until the filtrate is colorless. Dry the solid at 105℃ for 12 hours. Place the dried product in a tube furnace and heat it to 400℃ at 5℃ / min under a nitrogen atmosphere (200mL / min). Heat the product for 1 hour and allow it to cool naturally to obtain iron-modified biochar. (3) Take the prepared iron-modified biochar, dry it at 105℃ to constant weight, mix it with the functional bacterial suspension, place it in a shaker, shake and adsorb at 25℃ and 150rpm for 1.5 hours, filter it with sterile filter paper after adsorption, and collect the biochar loaded with bacteria. (4) Take proanthocyanidins and ZnCl2, and prepare proanthocyanidin solution and ZnCl2 solution respectively. Immerse the biochar loaded with bacteria in the proanthocyanidin solution at a mass-volume ratio of 1g:10mL, let it stand at room temperature for 15 minutes, and at the same time use magnetic stirring at 100rpm to assist diffusion. Filter, rinse gently with deionized water twice, and then immerse the above product in the ZnCl2 solution at a mass-volume ratio of 1g:10mL, let it stand at room temperature for 15 minutes, filter, rinse with deionized water twice, and repeat the above alternating immersion operation 5 times to obtain the self-assembled product. Spread the self-assembled product evenly on a stainless steel tray with a thickness not exceeding 2cm, place it in a vacuum freeze dryer, pre-freeze at -40℃ for 3 hours, dry once at -20℃ and vacuum degree 10Pa for 24 hours, and dry twice at 25℃ and vacuum degree 3Pa for 12 hours to obtain the functional bacterial agent.

[0035] The preparation method of the decomposed organic matter substrate is as follows: Weigh corn stalks, soybean meal, rice husks, astragalus root residue, γ-polyglutamic acid, and weathered coal humic acid, mix them evenly, adjust the moisture content to 65%, adjust the C / N ratio to 30:1, inoculate with a suspension of thermophilic denitrifying Bacillus, the inoculation amount is 5% (mass percentage concentration), and simultaneously add cellulase and lignin peroxidase, build up a pile, windrow type, 1.5m high, 3m wide at the bottom, with ventilation pipes laid at the bottom, ventilation volume 0.4 m 3 / (min·m 3 The fermentation cycle is 20 days: Turn the pile once a day from day 0 to 3 (medium temperature period, 45℃); turn the pile once every 2 days from day 4 to 10 (high temperature period, 65℃); turn the pile once every 3 days from day 11 to 20 (cooling and decomposition period, 20℃). After decomposition, sun-dry or dry with hot air at 40℃ until the moisture content is 15%, then crush and pass through a 60-mesh sieve to obtain the decomposed organic substrate. The mass ratio of corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, humic acid, cellulase, and lignin peroxidase is 15:3:2:2:1:2:0.02:0.01.

[0036] This embodiment also provides a method for preparing plant-derived bio-organic fertilizer, specifically including the following steps: S1. Add the decomposed organic substrate, additives, and wood ash to a double-helix conical mixer and mix for 15 minutes at 30 rpm. Add the functional microbial agent and continue mixing for 10 minutes. Then, pulverize urea, diammonium phosphate, and potassium sulfate separately through an 80-mesh sieve and slowly add them to the mixer. Continue mixing for 10 minutes until the color is uniform to obtain the mixed matrix. S2. The mixed matrix was granulated using a disc granulator, with the material moisture content controlled at 30%. The disc was tilted at 55°, the rotation speed was 25 rpm, and the granulation time was 15 minutes. The particle size was controlled at 5 mm. Fluidized bed drying was used with an inlet air temperature of 25°C until the moisture content was 5%. The granules were sieved, with a 6 mm sieve on the upper layer and a 1 mm sieve on the lower layer. The 6 mm granules were taken as the finished product, vacuum-packed in aluminum foil bags, and stored at 10°C in the dark to obtain plant-derived bio-organic fertilizer.

[0037] The difference between Comparative Example 1 and Example 2 is that the additive was omitted; otherwise, they are exactly the same as Example 2.

[0038] The difference between Comparative Example 2 and Example 2 is that the addition of the functional microbial agent was omitted, while the rest is exactly the same as Example 2.

[0039] Comparative Example 3 is a conventional commercially available bio-organic fertilizer.

[0040] Experimental example: 1. Effective viable bacteria count: Refer to the plate count method specified in NY 884-2012 "Bio-organic Fertilizer" and NY / T 798-2015 "Compound Microbial Fertilizer". Serially dilute the sample to be tested, spread it on the surface of a selective solid culture medium, and incubate under suitable conditions. Count the colony forming units (CFU) and calculate the number of viable bacteria per gram of sample. Weigh 10.0 g of the sample to be tested (accurate to 0.1 g), place it in an Erlenmeyer flask containing 90 mL of sterile physiological saline (0.85% NaCl), add an appropriate amount of glass beads, and shake for 30 minutes (200 rpm) to obtain 10... -1 Let the diluent stand for 1 minute, then aspirate the supernatant for further dilution. Take 1 mL of the 10⁻⁶ solution. -1 Diluent was added to a 9 mL sterile saline test tube, shaken well, and 10 was obtained. -2 Diluent, continue diluting to 10. -5 10 -6 10 -7 10 -8 (Determined based on expected bacterial count), take 0.1 mL of bacterial suspension at each dilution and spread it onto the surface of the corresponding selective medium plate. Perform 3 replicates for each dilution. Incubate upside down at the appropriate temperature until colonies grow. Select plates with colony counts between 30 and 300 for counting. Calculate the viable count using the following formula: The results are recorded in Table 1.

[0041] 2. Organic matter content: Refer to the potassium dichromate titration method specified in NY / T 525-2021 "Organic Fertilizers". Under heating conditions, excess potassium dichromate-sulfuric acid solution is used to oxidize the organic carbon in the sample. The remaining potassium dichromate is titrated with ferrous sulfate standard solution, and a blank test is performed with silica as an additive. The organic carbon content is calculated based on the amount of oxidant consumed before and after oxidation, and multiplied by the conversion factor of 1.724 to obtain the organic matter content. Potassium dichromate standard solution (c=0.1mol / L): Weigh 4.9030g of potassium dichromate dried at 130℃ for 2 hours, dissolve in water, transfer to a 1000mL volumetric flask, dilute to volume, and shake well; Ferrous sulfate standard solution (c=0.2mol / L): Weigh 55.6g of ferrous sulfate (FeSO4·7H2O), dissolve in an appropriate amount of water, add 5mL of concentrated sulfuric acid, transfer to a 1000mL volumetric flask, dilute to volume, and standardize with potassium dichromate standard solution before use; o-phenanthroline indicator: Weigh 1.485g of o-phenanthroline and 0.695g of ferrous sulfate, dissolve in 100mL of water, and store in a brown bottle; Concentrated sulfuric acid (ρ=1.84g / mL). Using the plant-derived bio-organic fertilizers prepared in Examples-3 and Comparative Examples 1-3 of this invention as test samples, the samples were air-dried, ground, sieved through a 0.5 mm sieve, and dried at 105 °C to constant weight. The moisture content was recorded. 0.3 g (accurate to 0.0001 g) of the sieved and air-dried sample was weighed and placed in a 500 mL Erlenmeyer flask. 30.0 mL of 0.1 mol / L potassium dichromate standard solution was accurately added, and the mixture was shaken thoroughly. Then, 60 mL of concentrated sulfuric acid was slowly added (while shaking). A small bent-neck funnel was added, and the mixture was heated in a boiling water bath for 30 minutes, with the solution being added every 5 minutes. Shake once every few minutes, remove and cool to room temperature, rinse the small funnel with water, collect the washings in an Erlenmeyer flask, transfer the reactants without damage to a 250mL volumetric flask, make up to volume, pipette 50mL of the solution into a 250mL Erlenmeyer flask, add about 100mL of water, add 2-3 drops of o-phenophylline indicator, and titrate with 0.2mol / L ferrous sulfate standard solution until the solution changes from green to dark green, and finally to brick red as the endpoint; perform a blank titration using silica (SiO2) instead of the sample; calculate the organic matter content and record the results in Table 1.

[0042] 3. Soil urease activity: Referring to the indophenol blue colorimetric method, urease hydrolyzes urea to produce ammonia (NH3) and carbonic acid. In a strongly alkaline medium, the released NH3 reacts with hypochlorite and phenol to produce blue indophenol blue, which has maximum light absorption at a wavelength of 578 nm. The ammonia nitrogen content is calculated by measuring the absorbance value, thereby characterizing the soil urease activity. 10% urea solution: Weigh 10g of urea, dissolve in deionized water and bring to a final volume of 100mL; Citrate buffer (pH 6.7): Weigh 18.4g of citric acid (C6H8O7·H2O) and 14.75g of potassium hydroxide (KOH), dissolve separately and combine, adjust the pH to 6.7 with 1mol / L NaOH, and bring to a final volume of 1000mL; Sodium phenolate solution: Solution A: Weigh 6.25g of phenol, dissolve in a small amount of anhydrous ethanol, and dilute to 100mL with anhydrous ethanol; Solution B: Weigh NaOH... 2.7g, dissolved in 100mL of water. Mix solutions A and B in a 1:1 ratio before use; Sodium hypochlorite solution (active chlorine concentration 0.9%): Take commercial sodium hypochlorite solution and dilute with water to an active chlorine concentration of 0.9%; Ammonia nitrogen standard solution: Weigh 0.4717g of (NH4)2SO4, dissolve in water and make up to 1000mL (NH3-N concentration 0.1mg / mL). Dilute 10 times before use to prepare the working solution (0.01mg / mL); Toluene: analytical grade, used to inhibit microbial activity. Take 0, 1, 3, 5, 7, and 9 mL of ammonia nitrogen working solution into 50 mL colorimetric tubes, add water to each tube to a final volume of 20 mL, add 4 mL of sodium phenolate solution, shake well, add 3 mL of sodium hypochlorite solution, shake well, and let stand for 20 minutes for color development. Dilute with water to the mark, and measure the absorbance at 578 nm wavelength, using the reagent blank as a reference. Plot a standard curve with ammonia nitrogen content (μg) on ​​the x-axis and absorbance values ​​on the y-axis. Weigh 5.0 g of air-dried soil sample that has passed through a 1 mm sieve into a 50 mL centrifuge tube, add 1 mL of toluene (to uniformly moisten the soil sample), and let stand for 15 minutes. After a few minutes, add 10 mL of 10% urea solution and 20 mL of citrate buffer (pH 6.7), shake well, cap the tube, and incubate at 37℃ for 24 hours. After incubation, filter the supernatant, transfer 1-5 mL of the filtrate to a 50 mL colorimetric tube (determined based on expected activity), add water to 20 mL, add 4 mL of sodium phenolate solution, shake well, add 3 mL of sodium hypochlorite solution, shake well, let stand for 20 minutes for color development, dilute with water to the mark, and measure the absorbance at 578 nm. Find the corresponding ammonia nitrogen content from the standard curve. Control settings: Soil-free blank: No soil sample added, all other operations are the same, reagent purity is checked; Matrix-free control: An equal volume of water is used instead of urea solution, all other operations are the same, the original ammonia nitrogen background in the soil is subtracted. Calculate urease activity, and record the results in Table 1.

[0043] Table 1: Performance Test Results of the Plant-Derived Bio-Organic Fertilizer of the Present Invention

[0044] As shown in Table 1, compared to Comparative Example 1, Example 2, after adding the additive, showed a significant increase in the number of effective viable bacteria, organic matter utilization rate, and soil urease activity. This demonstrates that the additive can optimize the fertilizer microenvironment, assist in preserving functional bacteria, and activate soil nutrients, exhibiting a good synergistic effect with the main fertilizer system. Comparative Example 2, without the addition of functional bacteria, showed no effective viable bacteria and a significant decrease in soil urease activity, indicating that the composite functional bacteria of this invention are the core key to activating soil enzyme activity and improving soil fertility, effectively activating the metabolic function of soil microorganisms. Compared to the three comparative examples, Examples 1-3 showed superior performance indicators, far exceeding those of conventional commercially available organic fertilizers. This fully verifies the inventiveness and practicality of the multi-level composite structure, functional bacteria, and special additive coupling system of this invention, demonstrating significant advantages in bacteria preservation, soil improvement, and nutrient activation.

[0045] Figure 1 The image shows a SEM image of the additive prepared according to the present invention. The additive exhibits an approximately spherical shape, uniform size, and dense arrangement. Figure 2 The results show that the plant-derived bio-organic fertilizers prepared in Examples 1-3 of this invention have a positive effect on Cd. 2+ The adsorption capacity of the sample was significantly higher than that of the comparative sample, indicating that the present invention significantly improves the adsorption capacity of organic fertilizer for Cd through the synergistic effect of functional microbial agents and additives. 2+ Its selective adsorption capacity.

[0046] In summary, this invention constructs an integrated preparation system comprising a full-temperature-range gradient composite microbial community system, a secondary thermosetting iron-modified biochar carrier, a polysaccharide composite for survival and protection, a multi-level coupling of a layer-by-layer self-assembled slow-release structure of metal polyphenols, and a molecularly imprinted bifunctional additive. This invention achieves full-temperature-range biological functional coverage during the organic fertilizer composting process and soil application through the compounding of differentiated functional strains. Relying on the stable adsorption and fixation effect of modified biochar and the biological survival effect of the polysaccharide protection system, it significantly improves the storage stability of functional microorganisms and their resistance to soil colonization. Combined with a multi-layered coating structure of metal polyphenol coordination, it achieves gradient slow release of bacteria and nutrients, solving the problems of sudden nutrient release and insufficient nutrient supply in the later stages of traditional fertilizers, and maintaining long-term rhizosphere microecological balance. Simultaneously, the additives endow the fertilizer with additional functions of targeted heavy metal passivation and auxiliary antibacterial activation, compensating for the shortcomings of traditional organic fertilizers, such as single function and lack of soil remediation capabilities. The various functional components are well-matched and synergistically enhanced, resulting in a plant-derived bio-organic fertilizer that possesses excellent composting properties, long-lasting biological activity, slow-release nutrient capacity, soil-borne disease control effects, and soil remediation and improvement performance. This effectively breaks through the technical bottlenecks of existing similar products, demonstrating significant overall technical advantages and possessing good application value and promotion prospects.

[0047] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A plant-derived bio-organic fertilizer, characterized in that, The raw materials include the following parts by weight: 50-70 parts decomposed organic substrate, 8-15 parts functional microbial agent, 3-8 parts additives, 2-5 parts urea, 4-8 parts diammonium phosphate, and 0.5-2 parts wood ash. The additive comprises the following raw materials in parts by weight: methacrylic acid: ZnCl2: ethylene glycol dimethacrylate: gallic acid: FeCl3·6H2O: sodium alginate: azobisisobutyronitrile = 0.3-0.5:0.2:4:1:1.2-1.5:2:0.03; The method for preparing the additive includes the following steps: (a) Take methacrylic acid and ZnCl2, dissolve them in a mixed solvent, stir magnetically, add ethylene glycol dimethacrylate and azobisisobutyronitrile, then add sodium alginate, stir to dissolve, polymerize under nitrogen protection, collect by centrifugation, wash, shake, and vacuum dry to obtain polymer microspheres; (b) Weigh gallic acid and dissolve it in deionized water to prepare a gallic acid solution, and weigh FeCl3·6H2O to prepare a FeCl3 solution; (c) The polymer microspheres were immersed in gallic acid solution, allowed to stand for impregnation, filtered, and washed to obtain a solid product. The solid product was then immersed in FeCl3 solution, allowed to stand for impregnation, filtered, washed, and freeze-dried under vacuum to obtain the additive.

2. The plant-derived bio-organic fertilizer according to claim 1, characterized in that, In step (a), the mixed solvent consists of methanol and deionized water in a volume ratio of 4:1; The ratio of ZnCl2 to the mixed solvent is 0.3-0.5g:20mL.

3. The plant-derived bio-organic fertilizer according to claim 1, characterized in that, The functional microbial agent comprises raw materials in the following ratio: corn stalk: FeCl3·6H2O: proanthocyanidins: ZnCl2: functional microbial suspension = 100g: 2.7g: 1-1.5g: 1.3g: 500mL; The preparation method of the functional microbial agent includes the following steps: (1) Take corn stalks, remove impurities, wash, dry with forced air, crush and sieve to obtain stalk powder, pyrolyze the stalk powder at a constant temperature under nitrogen atmosphere protection, and then cool to room temperature to obtain primary biochar. (2) Weigh FeCl3·6H2O and prepare FeCl3 solution. Add primary biochar to FeCl3 solution, disperse by ultrasonication, then impregnate by magnetic stirring, filter, wash, and dry to obtain dried product. Heat treat the dried product under nitrogen atmosphere and cool naturally to obtain iron-modified biochar. (3) Take the prepared iron-modified biochar, mix it with the functional bacterial suspension, shake to adsorb, filter, and obtain the biochar loaded with bacteria; (4) Take proanthocyanidins and ZnCl2, prepare proanthocyanidin solution and ZnCl2 solution, immerse the biochar loaded with bacteria in proanthocyanidin solution, let it stand for soaking, filter and rinse to obtain mixed product, immerse the mixed product in ZnCl2 solution, let it stand for soaking at room temperature, filter and rinse to obtain self-assembled product, freeze dry the self-assembled product under vacuum to obtain functional bacterial agent.

4. The plant-derived bio-organic fertilizer according to claim 3, characterized in that, The preparation process of the functional bacterial suspension is as follows: weigh thermophilic actinomycete suspension, Bacillus subtilis suspension and low-temperature nitrogen-fixing bacteria suspension and mix them in a volume ratio of 1-1.5:2:1 to obtain a mixed bacterial suspension. Add trehalose and skim milk powder to the mixed bacterial suspension and stir to obtain the functional bacterial suspension.

5. The plant-derived bio-organic fertilizer according to claim 3, characterized in that, In step (3), the mass-to-volume ratio of the iron-modified biochar to the functional bacterial suspension is 1 g: 5 mL.

6. The plant-derived bio-organic fertilizer according to claim 1, characterized in that, The preparation process of the decomposed organic matter substrate is as follows: weigh corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, and humic acid, mix them evenly, then inoculate with decomposition bacterial solution, then add cellulase and lignin peroxidase, pile up, turn the pile, decompose and dry, crush and sieve to obtain decomposed organic matter substrate. The mass ratio of corn stalks, soybean meal, rice husks, astragalus residue, γ-polyglutamic acid, humic acid, cellulase, and lignin peroxidase is 10-15:3:2:2:1:2:0.02:0.

01.

7. A method for preparing plant-derived bio-organic fertilizer according to any one of claims 1-6, characterized in that, Specifically, the following steps are included: S1, weigh out the decomposed organic substrate, additives, and wood ash, stir and mix them, add functional microbial agent, continue mixing, then add urea, diammonium phosphate, and potassium sulfate, and continue stirring to obtain a mixed matrix; S2, granulate, dry, and package the mixed matrix to obtain plant-derived bio-organic fertilizer.

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