A zinc-rich organic fertilizer and a preparation method thereof
Through the synergistic effect of compound chelating agents and microbial agents, the problem of insufficient zinc availability and stability in zinc-rich organic fertilizers has been solved, achieving efficient, stable release and balanced supply of zinc, thus improving the application effect of fertilizers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG ACADEMY OF AGRICULTURAL SCIENCES
- Filing Date
- 2026-01-13
- Publication Date
- 2026-05-29
AI Technical Summary
The availability and stability of zinc in existing zinc-enriched organic fertilizers are insufficient. Traditional chelated zinc has weak chelating ability, is easily hydrolyzed and deactivated, or is difficult to biodegrade, resulting in an effective zinc utilization rate of less than 30%.
A composite chelating agent, consisting of modified humic acid and tea polyphenols, is used to form synergistic chelating sites. Combined with microbial agents such as Priscilla argentis and Bacillus subtilis, the stable release of zinc is achieved through the synergistic effects of chelation, dissolution, and absorption, along with an organic substrate and a slow-release coating agent.
It significantly improves the chelation rate and bioavailability of zinc, ensures the stable existence of zinc in the soil, enhances the utilization rate of available zinc, avoids poor crop growth caused by single nutrient deficiency, and achieves balanced supply and long-term release of zinc.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of organic fertilizer technology, and more specifically, to a zinc-rich organic fertilizer and its preparation method. Background Technology
[0002] Zinc-enriched organic fertilizers are widely used in agricultural production because they combine the dual benefits of soil improvement through organic fertilizer and the supplementation of crop nutrition with zinc. However, existing technologies have significant drawbacks: Insufficient zinc availability and stability; inorganic zinc is easily fixed by soil; traditional chelated zinc (such as EDTA chelated zinc and single amino acid chelated zinc) suffer from weak chelating ability, easy hydrolysis and inactivation, or difficulty in biodegradation, resulting in an effective zinc utilization rate of less than 30%. Therefore, the present invention proposes a zinc-rich organic fertilizer and its preparation method, which has important practical significance. Summary of the Invention
[0003] In view of this, the present invention proposes a zinc-rich organic fertilizer and its preparation method, aiming to solve the problems of insufficient zinc availability and stability in the above-mentioned background technology.
[0004] This invention proposes a zinc-rich organic fertilizer comprising the following components in parts by weight: The ingredients include 40-60 parts organic substrate, 5-8 parts composite zinc source, 3-5 parts composite chelating agent, 2-3 parts functional microbial agent, 0.3-0.5 parts magnesium sulfate, 0.2-0.3 parts manganese sulfate, 0.2-0.3 parts boric acid, 0.1-0.2 parts ammonium molybdate, 2-4 parts slow-release coating agent, and 1-2 parts zeolite powder.
[0005] Furthermore, the method for preparing the organic substrate is as follows: After crushing the livestock and poultry manure, add water at a solid-liquid ratio of 1:5, stir to form a slurry, and adjust the pH to 6.5-7.0 to obtain the livestock and poultry manure slurry. The aminophosphonic acid chelating resin was activated by soaking in 5% hydrochloric acid solution for 2 hours, washed with water until neutral, and then packed into the adsorption column. The livestock and poultry manure slurry was added to an adsorption column and adsorbed at room temperature until the zinc content of the effluent was ≤50mg / kg. The adsorption was then stopped to obtain pretreated livestock and poultry manure. The pretreated livestock and poultry manure, crop straw, and kitchen waste fermentation residue are mixed in a mass ratio of 2:1:1 to obtain an organic substrate.
[0006] Furthermore, the composite zinc source is composed of zinc sulfate and zinc oxide in a mass ratio of 1:1; the composite chelating agent is composed of modified humic acid and tea polyphenols in a mass ratio of 3:2.
[0007] Furthermore, the preparation method of the modified humic acid is as follows: Humic acid powder and water were mixed in a mass ratio of 1:3 and stirred to form a suspension. The pH was adjusted to 2.0-2.5 with 10% hydrochloric acid solution. The mixture was stirred at room temperature for 30 minutes. After filtration, the filter cake was collected and washed with water until the pH of the filtrate was ≥4.0. The filtrate was dried in an oven at 80℃ to constant weight to obtain pretreated humic acid. The pretreated humic acid was added to water at a solid-liquid ratio of 1:10, and the temperature was raised to 50°C. 20% of the mass of the pretreated humic acid in a 30% hydrogen peroxide solution was added dropwise. After the addition was completed, the temperature was raised to 60°C and stirred at a constant temperature for 2 hours. After the addition was completed, the pH of the reaction solution was adjusted to 6.0-6.5 with a 10% sodium hydroxide solution. The mixture was allowed to stand for 4 hours to precipitate, and the filter cake was collected by filtration. The cake was washed three times with water and vacuum dried at 80°C and -0.08 MPa until the moisture content was 10%. The cake was then pulverized to 200 mesh to obtain the modified humic acid.
[0008] Furthermore, the functional microbial agent is composed of *Priscilla argentea* and *Bacillus subtilis* mixed at a live bacteria ratio of 2:1.
[0009] Furthermore, the sustained-release coating agent is composed of starch and chitosan in a mass ratio of 4:1.
[0010] This invention also provides a method for preparing zinc-rich organic fertilizer, comprising the following preparation steps: The composite zinc source was added to water, stirred and dissolved, and the pH was adjusted to 5.0-5.5 to obtain a composite zinc source solution. The composite chelating agent is added to the composite zinc source solution for chelation treatment to obtain a chelated zinc concentrate. The organic substrate is mixed with zeolite powder and then fermented in stages. During the fermentation, the chelated zinc concentrate and functional microbial agent are added. After the fermentation is completed, magnesium sulfate, manganese sulfate, boric acid and ammonium molybdate are added and stirred to obtain the fermented material. After the fermentation material is coated with the slow-release coating agent, the zinc-rich organic fertilizer is obtained.
[0011] Furthermore, the chelation treatment specifically involves: constant temperature stirring at 55°C for 3 hours followed by vacuum concentration until the solid content reaches 40%.
[0012] Furthermore, the segmented fermentation specifically includes: The organic substrate was mixed with zeolite powder and fermented at 55-65℃ for 7 days, during which time it was fed with a 0.4m... 3 / (m 3 Air is introduced at a rate of h), and after the fermentation is completed, the fermentation temperature is lowered to 30-35℃. The chelated zinc concentrate is then sprayed and stirred. After spraying, the functional microbial agent is inoculated and sealed for anaerobic fermentation for 9 days.
[0013] Furthermore, the sustained-release coating specifically includes: The slow-release coating agent was dissolved in a 5% acetic acid solution at a solid-liquid ratio of 1:10 to obtain a coating solution. The fermented material was pulverized and sprayed with the coating solution. After spraying, it was dried at a low temperature of 50°C for 2.5 hours.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a composite chelating agent to chelate the zinc source. The carboxyl and hydroxyl groups of the modified humic acid in the composite chelating agent form synergistic chelating sites with the phenolic hydroxyl groups of tea polyphenols, thereby improving the chelation rate of the composite chelated zinc. Moreover, after being applied to the soil, it is not easy to combine with calcium carbonate and phosphate to form insoluble compounds, thus greatly improving the utilization rate of effective zinc.
[0015] 2. This invention also incorporates a microbial compound agent, including *Priscilla auriculata* (…). Priestia aryabhattai The organic acids secreted by the plant can further dissolve fixed zinc in the soil, while its metabolites, extracellular polysaccharides, can enhance the absorption capacity of crop roots, forming a "dissolution-chelation-absorption" synergistic effect with the compound chelated zinc, which greatly improves the bioavailability of zinc.
[0016] 3. The organic substrate of the present invention, after being fermented in stages, forms rich humus, amino acids and other organic nutrients, which are combined with precisely proportioned nitrogen, phosphorus, potassium and trace elements such as iron, manganese, boron and molybdenum to achieve a balanced supply of "organic nutrients + zinc + trace elements", avoiding poor crop growth caused by the lack of a single nutrient. At the same time, the starch-chitosan coating layer enables the gradient release of zinc. Detailed Implementation
[0017] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.
[0018] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0019] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0020] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0021] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0022] This invention provides a zinc-enriched organic fertilizer, comprising the following components in parts by weight: The ingredients include 40-60 parts organic substrate, 5-8 parts composite zinc source, 3-5 parts composite chelating agent, 2-3 parts functional microbial agent, 0.3-0.5 parts magnesium sulfate, 0.2-0.3 parts manganese sulfate, 0.2-0.3 parts boric acid, 0.1-0.2 parts ammonium molybdate, 2-4 parts slow-release coating agent, and 1-2 parts zeolite powder.
[0023] The preferred mass fractions of each component in the zinc-rich organic fertilizer are: The composition includes 50 parts organic substrate, 7 parts composite zinc source, 4 parts composite chelating agent, 2.5 parts functional microbial agent, 0.4 parts magnesium sulfate, 0.3 parts manganese sulfate, 0.3 parts boric acid, 0.2 parts ammonium molybdate, 3 parts slow-release coating agent, and 1.5 parts zeolite powder.
[0024] It is understood that the present invention uses a composite chelating agent to chelate the zinc source. The carboxyl and hydroxyl groups of the modified humic acid in the composite chelating agent form synergistic chelating sites with the phenolic hydroxyl groups of tea polyphenols, thereby improving the chelation rate of the composite chelated zinc. Moreover, after being applied to the soil, it is not easy to combine with calcium carbonate and phosphate to form insoluble compounds, thus greatly improving the utilization rate of effective zinc.
[0025] It is understood that this invention also incorporates a microbial compound agent, including *Priscilla auriculata* (…). Priestia aryabhattai The organic acids secreted by the plant can further dissolve fixed zinc in the soil, while its metabolites, extracellular polysaccharides, can enhance the absorption capacity of crop roots, forming a "dissolution-chelation-absorption" synergistic effect with the compound chelated zinc, which greatly improves the bioavailability of zinc.
[0026] In this invention, the method for preparing the organic substrate is as follows: After crushing the livestock and poultry manure, add water at a solid-liquid ratio of 1:5 (m / v), stir to form a slurry, and adjust the pH to 6.5-7.0 to obtain the livestock and poultry manure slurry. The aminophosphonic acid chelating resin was activated by soaking in 5% hydrochloric acid solution for 2 hours, washed with water until neutral, and then packed into the adsorption column. The livestock and poultry manure slurry was added to an adsorption column and adsorbed at room temperature until the zinc content of the effluent was ≤50mg / kg. The adsorption was then stopped to obtain pretreated livestock and poultry manure. The pretreated livestock and poultry manure, crop straw, and kitchen waste fermentation residue are mixed in a mass ratio of 2:1:1 to obtain an organic substrate.
[0027] Specifically, the aminophosphonic acid chelating resin is model Lewatit TP 207; the height-to-diameter ratio of the adsorption column is 10:1; Specifically, when adding the livestock and poultry manure slurry to the adsorption column, the livestock and poultry manure slurry is pumped into the adsorption column, and its flow rate is controlled at 2 BV / h (BV is the resin bed volume); during adsorption, the zinc content of the effluent is sampled and detected every 0.5h until the zinc content of the effluent is ≤50mg / kg, at which point adsorption is stopped.
[0028] Understandably, controlling the zinc content of livestock and poultry manure to ≤50mg / kg can effectively avoid the problem of excessive zinc due to feed additive residues, prevent abnormal increases in the zinc content of subsequent fertilizer products, and thus avoid the risk of soil zinc accumulation pollution and excessive zinc in agricultural products caused by long-term application. At the same time, it can provide a stable base material for the subsequent precise addition of compound zinc sources, ensure a balanced fertilizer nutrient ratio, avoid unstable fertilizer effect due to fluctuations in the zinc content of the base material, and ultimately improve the safety and reliability of fertilizer application.
[0029] In this invention, the composite zinc source is composed of zinc sulfate and zinc oxide in a mass ratio of 1:1; the composite chelating agent is composed of modified humic acid and tea polyphenols in a mass ratio of 3:2.
[0030] The modified humic acid is prepared by: Humic acid powder and water were mixed in a mass ratio of 1:3 and stirred to form a suspension. The pH was adjusted to 2.0-2.5 with 10% hydrochloric acid solution. The mixture was stirred at room temperature for 30 minutes. After filtration, the filter cake was collected and washed with water until the pH of the filtrate was ≥4.0. The filtrate was dried in an oven at 80℃ to constant weight to obtain pretreated humic acid. The pretreated humic acid was added to water at a solid-liquid ratio of 1:10 (m / v), and the temperature was raised to 50°C. 20% of the mass of the pretreated humic acid in a 30% hydrogen peroxide solution was added dropwise. After the addition was completed, the temperature was raised to 60°C and stirred at a constant temperature for 2 hours. After the addition was completed, the pH of the reaction solution was adjusted to 6.0-6.5 with a 10% sodium hydroxide solution. The mixture was allowed to stand for 4 hours to precipitate, and the filter cake was collected by filtration. The cake was washed three times with water and vacuum dried at 80°C and -0.08 MPa until the moisture content was 10%. The cake was then pulverized to 200 mesh to obtain the modified humic acid.
[0031] Specifically, the humic acid raw powder has a purity of ≥70%, a moisture content of ≤15%, an ash content of ≤20%, and is pulverized to a particle size of ≤100 mesh.
[0032] Understandably, humic acid, after being modified by oxidation and oxidation, has a significantly increased carboxyl content, enabling it to form synergistic chelating sites with tea polyphenols. This significantly enhances its chelating ability for zinc ions, improving the chelation rate and stability constant of the composite chelated zinc. This not only prevents zinc from being fixed by calcium carbonate, phosphate, etc. after being applied to the soil, but also maintains stability in a wide range of soil pH 4.0-8.0, greatly improving the utilization rate of effective zinc. At the same time, it is derived from natural raw materials such as weathered coal, and the composite chelating agent formed by combining it with tea polyphenols can be naturally degraded without chemical residues, meeting the needs of eco-friendliness. It can also work synergistically with functional microorganisms to help improve the soil microenvironment, laying the foundation for balanced nutrient supply and long-lasting fertilizer effect.
[0033] In this invention, the functional microbial agent is composed of *Priscilla auriculata* and *Bacillus subtilis* mixed at a live bacteria ratio of 2:1.
[0034] Specifically, the *Priestella auriculata* is preferably the strain with accession number DSM 21047, and the *Bacillus subtilis* is preferably the strain with accession number CGMCC No. 3936. Both strains are existing strains that have been publicly deposited.
[0035] Specifically, the total viable count of the functional microbial agent is ≥1×10⁻⁶. 9 CFU / g.
[0036] It is understandable that *Priestia aryabhattai* can secrete organic acids such as citric acid and gluconic acid, converting insoluble zinc in the soil and incompletely chelated zinc in fertilizers into an absorbable form for crops. Simultaneously, the extracellular polysaccharides produced by its metabolism can enhance the absorption capacity of crop roots, synergistically constructing a highly efficient zinc supply pathway of "dissolution-chelation-absorption" with compound chelated zinc. *Bacillus subtilis* can fix free nitrogen in the air into ammonia nitrogen available to crops, and can also decompose insoluble phosphorus mineralization in the soil to form available phosphorus, supplementing soil nitrogen and phosphorus nutrients. The combination of these two can significantly improve the bioavailability of zinc, compensate for the lack of nitrogen and phosphorus nutrients in organic substrates, improve the soil microbial community structure, and enhance soil enzyme activity, laying the foundation for balanced fertilizer supply and healthy crop growth.
[0037] In this invention, the sustained-release coating agent is composed of starch and chitosan in a mass ratio of 4:1.
[0038] Understandably, slow-release coating agents can form a dense coating layer on the surface of fertilizer granules. Starch is a readily biodegradable component, and amylases in the soil can preferentially decompose starch within 1-30 days, creating tiny pores on the surface of the coating layer, allowing nutrients to slowly seep out to meet the needs of seedlings. After the starch has largely degraded (31-80 days), the coating layer is mainly composed of recalcitrant chitosan. Chitinase-producing bacteria in the soil gradually decompose the chitosan, causing the pores of the coating layer to expand and partially rupture, accelerating the nutrient release rate and achieving a concentrated release of 40% of the nutrients to match the needs of crops during their vigorous growth period. The remaining chitosan slowly degrades within 81-120 days, and the coating layer gradually disintegrates.
[0039] This invention also provides a method for preparing zinc-rich organic fertilizer, comprising the following preparation steps: The composite zinc source was added to water, stirred and dissolved, and the pH was adjusted to 5.0-5.5 to obtain a composite zinc source solution. The composite chelating agent is added to the composite zinc source solution for chelation treatment to obtain a chelated zinc concentrate. The organic substrate is mixed with zeolite powder and then fermented in stages. During the fermentation, the chelated zinc concentrate and functional microbial agent are added. After the fermentation is completed, magnesium sulfate, manganese sulfate, boric acid and ammonium molybdate are added and stirred to obtain the fermented material. After the fermentation material is coated with the slow-release coating agent, the zinc-rich organic fertilizer is obtained.
[0040] It is understood that the organic substrate of the present invention, after being fermented in stages, forms rich humus, amino acids and other organic nutrients, which, combined with precisely proportioned nitrogen, phosphorus, potassium and trace elements such as iron, manganese, boron and molybdenum, achieve a balanced supply of "organic nutrients + zinc + trace elements", avoiding poor crop growth caused by a lack of a single nutrient.
[0041] In this invention, the chelation treatment specifically involves: stirring at a constant temperature of 55°C for 3 hours, followed by vacuum concentration until the solid content is 40%.
[0042] Specifically, the composite zinc source is added to water at a solid-liquid ratio of 1:10 (m / v), and the pH is adjusted to 5.0-5.5 to obtain a composite zinc source solution. A composite chelating agent is added to the composite zinc source solution, and the mixture is stirred at a constant temperature of 55°C for 3 hours and then vacuum concentrated to a solid content of 40% to obtain a chelated zinc concentrate.
[0043] Understandably, the composite zinc source, a mixture of zinc sulfate and zinc oxide, is first dissolved at a solid-liquid ratio of 1:10 and the pH is adjusted to 5.0-5.5 to provide a suitable acid-base environment for the chelation reaction, ensuring that zinc ions can efficiently bind with the chelating agent. Then, the composite chelating agent is added in proportion and reacted at a constant temperature of 50-60℃ for 2-3 hours to promote the formation of synergistic chelating sites between the carboxyl and hydroxyl groups of modified humic acid and the phenolic hydroxyl groups of tea polyphenols, maximizing the zinc ion chelation rate. At the same time, concentration can effectively chelate zinc components and reduce moisture interference when mixing with the fermentation substrate.
[0044] In this invention, the segmented fermentation specifically refers to: The organic substrate was mixed with zeolite powder and fermented at 55-65℃ for 7 days, during which time it was fed with a 0.4m... 3 / (m 3 Air is introduced at a rate of h), and after the fermentation is completed, the fermentation temperature is lowered to 30-35℃. The chelated zinc concentrate is then sprayed and stirred. After spraying, the functional microbial agent is inoculated and sealed for anaerobic fermentation for 9 days.
[0045] Specifically, after mixing the organic substrate with zeolite powder, a first-stage high-temperature fermentation is carried out: the temperature is raised to 60°C, and air is introduced (air flow rate 0.4m). 3 / (m 3 ·h)), ferment for 7 days, turning once a day during this period; after the fermentation is completed, carry out the second stage of low-temperature fermentation: lower the temperature to 30-35℃, first spray the chelated zinc concentrate, stir evenly, then inoculate with functional microbial agents, seal and anaerobic ferment for 9 days, during which the pH is controlled to be stable between 6.5-7.2.
[0046] Understandably, the first stage of high-temperature aerobic fermentation at 55-65℃ can remove pathogens and weed seeds from livestock and poultry manure, while efficiently degrading large organic molecules into small molecule nutrients, laying a safe and easily usable substrate foundation for subsequent fermentation; the second stage of low-temperature anaerobic fermentation at 30-35℃ precisely matches the optimal growth temperature of functional microorganisms (Priestia aryabhattai and Bacillus subtilis), enabling them to reproduce efficiently in a stable pH environment, which not only enhances the zinc-dissolving bacteria's ability to convert and dissolve zinc, but also enhances the activity of organic nutrients.
[0047] In this invention, the sustained-release coating specifically refers to: The slow-release coating agent was dissolved in a 5% acetic acid solution at a solid-liquid ratio of 1:10 (m / v) to obtain a coating solution. The fermented material was then pulverized and sprayed into the coating solution. After spraying, the material was dried at a low temperature of 50°C for 2.5 hours.
[0048] Specifically, the slow-release coating agent is dissolved in a 5% acetic acid solution at a solid-liquid ratio of 1:10 (m / v) to obtain a coating solution. The fermented material is then pulverized to a particle size of 20-40 mesh and fed into a coating machine. The coating solution is then sprayed on the material, and after spraying, it is dried at a low temperature of 50°C for 2.5 hours.
[0049] The water used in this invention is preferably deionized water.
[0050] Example 1 Raw material components and dosage: 40 parts organic base material, 5 parts composite zinc source, 3 parts composite chelating agent, 2 parts functional microbial agent, 0.3 parts magnesium sulfate, 0.2 parts manganese sulfate, 0.2 parts boric acid, 0.1 parts ammonium molybdate, 2 parts slow-release coating agent, and 1 part zeolite powder.
[0051] Preparation of raw material components: Organic substrate: After crushing livestock and poultry manure, deionized water is added at a solid-liquid ratio of 1:5 and stirred into a slurry. The pH is adjusted to 6.5-7.0 to obtain livestock and poultry manure slurry. Aminophosphonic acid chelating resin is activated by soaking in 5% hydrochloric acid solution for 2 hours, washed with water until neutral, and then packed into an adsorption column. The livestock and poultry manure slurry is added to the adsorption column and adsorbed at room temperature until the zinc content of the effluent is ≤50mg / kg. Adsorption is then stopped to obtain pretreated livestock and poultry manure. The pretreated livestock and poultry manure, crop straw, and kitchen waste fermentation residue are mixed at a mass ratio of 2:1:1 to obtain the organic substrate.
[0052] Composite zinc source: It is made by compounding zinc sulfate and zinc oxide in a mass ratio of 1:1.
[0053] Composite chelating agent: Humic acid powder and water were mixed in a mass ratio of 1:3 to form a suspension. The pH was adjusted to 2.0-2.5 with 10% hydrochloric acid solution. The mixture was stirred at room temperature for 30 min. After filtration, the filter cake was collected and washed with water until the pH of the filtrate was ≥4.0. The filtrate was dried in an oven at 80℃ to constant weight to obtain pretreated humic acid. The pretreated humic acid was added to water in a solid-liquid ratio of 1:10. The temperature was raised to 50℃, and 20% (by weight) of the pretreated humic acid in a 30% hydrogen peroxide solution was added dropwise. After the addition was completed, the temperature was raised to 60℃ and stirred at a constant temperature for 2 h. After the addition was completed, the pH of the reaction solution was adjusted to 6.0-6.5 with 10% sodium hydroxide solution. The mixture was allowed to stand for 4 h to precipitate. The filter cake was collected and washed with water three times. The mixture was then vacuum dried at 80℃ and -0.08 MPa until the moisture content was 10% to obtain the modified humic acid. The modified humic acid was compounded with tea polyphenols in a mass ratio of 3:2 to obtain a composite chelating agent.
[0054] Microbial inoculant: It is a mixture of *Priscilla argentea* and *Bacillus subtilis* at a live count ratio of 2:1, wherein *Priscilla argentea* is a strain with accession number DSM 21047 and *Bacillus subtilis* is a strain with accession number CGMCC No. 3936.
[0055] Sustained-release coating agent: composed of starch and chitosan in a mass ratio of 4:1.
[0056] Preparation method: S1. Add the composite zinc source to deionized water at a solid-liquid ratio of 1:10, stir to dissolve, and adjust the pH to between 5.0 and 5.5 to obtain the composite zinc source solution. S2. Add a composite chelating agent to the composite zinc source solution, stir at a constant temperature of 55°C for 3 hours, and then concentrate under vacuum to a solid content of 40% to obtain a chelated zinc concentrate. S3. After mixing the organic substrate with zeolite powder evenly, transfer the mixture to a fermentation tank and heat it to between 55-65℃. Then, use a 0.4m... 3 / (m 3 Air was introduced at a rate of h) and fermented for 7 days, during which the mixture was turned over once a day. After the fermentation was completed, the temperature was lowered to between 30-35℃. The compound chelated zinc concentrate was sprayed first and stirred evenly. Then, functional microbial agents were inoculated and sealed for anaerobic fermentation for 9 days, during which the pH was controlled to be stable at 6.5-7.2. After the fermentation was completed, magnesium sulfate, manganese sulfate, boric acid and ammonium molybdate were added to the fermentation system and mixed evenly to obtain the fermented material. S4. Dissolve the slow-release coating agent in a 5% acetic acid solution at a solid-liquid ratio of 1:10 to obtain a coating solution. Crush the fermented material to 20-40 mesh, feed it into a coating machine, spray the coating solution, and dry it at a low temperature of 50°C for 2.5 hours after spraying to obtain zinc-rich organic fertilizer.
[0057] Example 2 Raw material components and dosage: 50 parts organic base material, 7 parts composite zinc source, 4 parts composite chelating agent, 2.5 parts functional microbial agent, 0.4 parts magnesium sulfate, 0.3 parts manganese sulfate, 0.3 parts boric acid, 0.2 parts ammonium molybdate, 3 parts slow-release coating agent, and 1.5 parts zeolite powder.
[0058] Preparation of raw material components: Organic substrate: After crushing livestock and poultry manure, deionized water is added at a solid-liquid ratio of 1:5 and stirred into a slurry. The pH is adjusted to 6.5-7.0 to obtain livestock and poultry manure slurry. Aminophosphonic acid chelating resin is activated by soaking in 5% hydrochloric acid solution for 2 hours, washed with water until neutral, and then packed into an adsorption column. The livestock and poultry manure slurry is added to the adsorption column and adsorbed at room temperature until the zinc content of the effluent is ≤50mg / kg. Adsorption is then stopped to obtain pretreated livestock and poultry manure. The pretreated livestock and poultry manure, crop straw, and kitchen waste fermentation residue are mixed at a mass ratio of 2:1:1 to obtain the organic substrate.
[0059] Composite zinc source: It is made by compounding zinc sulfate and zinc oxide in a mass ratio of 1:1.
[0060] Composite chelating agent: Humic acid powder and water were mixed in a mass ratio of 1:3 to form a suspension. The pH was adjusted to 2.0-2.5 with 10% hydrochloric acid solution. The mixture was stirred at room temperature for 30 min. After filtration, the filter cake was collected and washed with water until the pH of the filtrate was ≥4.0. The filtrate was dried in an oven at 80℃ to constant weight to obtain pretreated humic acid. The pretreated humic acid was added to water in a solid-liquid ratio of 1:10. The temperature was raised to 50℃, and 20% (by weight) of the pretreated humic acid in a 30% hydrogen peroxide solution was added dropwise. After the addition was completed, the temperature was raised to 60℃ and stirred at a constant temperature for 2 h. After the addition was completed, the pH of the reaction solution was adjusted to 6.0-6.5 with 10% sodium hydroxide solution. The mixture was allowed to stand for 4 h to precipitate. The filter cake was collected and washed with water three times. The mixture was then vacuum dried at 80℃ and -0.08 MPa until the moisture content was 10% to obtain the modified humic acid. The modified humic acid was compounded with tea polyphenols in a mass ratio of 3:2 to obtain a composite chelating agent.
[0061] Microbial inoculant: It is a mixture of *Priscilla argentea* and *Bacillus subtilis* at a live count ratio of 2:1, wherein *Priscilla argentea* is a strain with accession number DSM 21047 and *Bacillus subtilis* is a strain with accession number CGMCC No. 3936.
[0062] Sustained-release coating agent: composed of starch and chitosan in a mass ratio of 4:1.
[0063] Preparation method: S1. Add the composite zinc source to deionized water at a solid-liquid ratio of 1:10, stir to dissolve, and adjust the pH to between 5.0 and 5.5 to obtain the composite zinc source solution. S2. Add a composite chelating agent to the composite zinc source solution, stir at a constant temperature of 55°C for 3 hours, and then concentrate under vacuum to a solid content of 40% to obtain a chelated zinc concentrate. S3. After mixing the organic substrate with zeolite powder evenly, transfer the mixture to a fermentation tank and heat it to between 55-65℃. Then, use a 0.4m... 3 / (m 3 Air was introduced at a rate of h) and fermented for 7 days, during which the mixture was turned over once a day. After the fermentation was completed, the temperature was lowered to between 30-35℃. The compound chelated zinc concentrate was sprayed first and stirred evenly. Then, functional microbial agents were inoculated and sealed for anaerobic fermentation for 9 days, during which the pH was controlled to be stable at 6.5-7.2. After the fermentation was completed, magnesium sulfate, manganese sulfate, boric acid and ammonium molybdate were added to the fermentation system and mixed evenly to obtain the fermented material. S4. Dissolve the slow-release coating agent in a 5% acetic acid solution at a solid-liquid ratio of 1:10 to obtain a coating solution. Crush the fermented material to 20-40 mesh, feed it into a coating machine, spray the coating solution, and dry it at a low temperature of 50°C for 2.5 hours after spraying to obtain zinc-rich organic fertilizer.
[0064] Example 3 Raw material components and dosage: 60 parts organic base material, 8 parts composite zinc source, 5 parts composite chelating agent, 3 parts functional microbial agent, 0.5 parts magnesium sulfate, 0.3 parts manganese sulfate, 0.3 parts boric acid, 0.2 parts ammonium molybdate, 4 parts slow-release coating agent, and 2 parts zeolite powder.
[0065] Preparation of raw material components: Organic substrate: After crushing livestock and poultry manure, deionized water is added at a solid-liquid ratio of 1:5 and stirred into a slurry. The pH is adjusted to 6.5-7.0 to obtain livestock and poultry manure slurry. Aminophosphonic acid chelating resin is activated by soaking in 5% hydrochloric acid solution for 2 hours, washed with water until neutral, and then packed into an adsorption column. The livestock and poultry manure slurry is added to the adsorption column and adsorbed at room temperature until the zinc content of the effluent is ≤50mg / kg. Adsorption is then stopped to obtain pretreated livestock and poultry manure. The pretreated livestock and poultry manure, crop straw, and kitchen waste fermentation residue are mixed at a mass ratio of 2:1:1 to obtain the organic substrate.
[0066] Composite zinc source: It is made by compounding zinc sulfate and zinc oxide in a mass ratio of 1:1.
[0067] Composite chelating agent: Humic acid powder and water were mixed in a mass ratio of 1:3 to form a suspension. The pH was adjusted to 2.0-2.5 with 10% hydrochloric acid solution. The mixture was stirred at room temperature for 30 min. After filtration, the filter cake was collected and washed with water until the pH of the filtrate was ≥4.0. The filtrate was dried in an oven at 80℃ to constant weight to obtain pretreated humic acid. The pretreated humic acid was added to water in a solid-liquid ratio of 1:10. The temperature was raised to 50℃, and 20% (by weight) of the pretreated humic acid in a 30% hydrogen peroxide solution was added dropwise. After the addition was completed, the temperature was raised to 60℃ and stirred at a constant temperature for 2 h. After the addition was completed, the pH of the reaction solution was adjusted to 6.0-6.5 with 10% sodium hydroxide solution. The mixture was allowed to stand for 4 h to precipitate. The filter cake was collected and washed with water three times. The mixture was then vacuum dried at 80℃ and -0.08 MPa until the moisture content was 10% to obtain the modified humic acid. The modified humic acid was compounded with tea polyphenols in a mass ratio of 3:2 to obtain a composite chelating agent.
[0068] Microbial inoculant: It is a mixture of *Priscilla argentea* and *Bacillus subtilis* at a live count ratio of 2:1, wherein *Priscilla argentea* is a strain with accession number DSM 21047 and *Bacillus subtilis* is a strain with accession number CGMCC No. 3936.
[0069] Sustained-release coating agent: composed of starch and chitosan in a mass ratio of 4:1.
[0070] Preparation method: S1. Add the composite zinc source to deionized water at a solid-liquid ratio of 1:10, stir to dissolve, and adjust the pH to between 5.0 and 5.5 to obtain the composite zinc source solution. S2. Add a composite chelating agent to the composite zinc source solution, stir at a constant temperature of 55°C for 3 hours, and then concentrate under vacuum to a solid content of 40% to obtain a chelated zinc concentrate. S3. After mixing the organic substrate with zeolite powder evenly, transfer the mixture to a fermentation tank and heat it to between 55-65℃. Then, use a 0.4m... 3 / (m 3 Air was introduced at a rate of h) and fermented for 7 days, during which the mixture was turned over once a day. After the fermentation was completed, the temperature was lowered to between 30-35℃. The compound chelated zinc concentrate was sprayed first and stirred evenly. Then, functional microbial agents were inoculated and sealed for anaerobic fermentation for 9 days, during which the pH was controlled to be stable at 6.5-7.2. After the fermentation was completed, magnesium sulfate, manganese sulfate, boric acid and ammonium molybdate were added to the fermentation system and mixed evenly to obtain the fermented material. S4. Dissolve the slow-release coating agent in a 5% acetic acid solution at a solid-liquid ratio of 1:10 to obtain a coating solution. Crush the fermented material to 20-40 mesh, feed it into a coating machine, spray the coating solution, and dry it at a low temperature of 50°C for 2.5 hours after spraying to obtain zinc-rich organic fertilizer.
[0071] Test Example 1 Fertilizer testing and grouping F-Complete group: Zinc-rich organic fertilizer prepared in Example 2 of this invention.
[0072] F-NoMicrobe group: Compared to the F-Complete group, no functional microbial agents were inoculated.
[0073] F-NoCoat group: Compared to the F-Complete group, it does not undergo starch-chitosan coating.
[0074] F-Chelate group: Compared to F-Complete group, it contains only an organic matrix of complex chelated zinc (no inoculation, no coating).
[0075] F-Sulfate group: An equal amount of zinc sulfate is physically mixed with an organic matrix that has been sterilized at high temperature (F-Complete is sterilized at 121°C for 30 minutes).
[0076] Test soil Type: Calcareous clay loam, collected from the 0-20 cm topsoil layer of farmland in the North China Plain.
[0077] Pretreatment: After air drying, pass through a 2 mm sieve and mix evenly.
[0078] Basic physicochemical properties: pH = 8.25 (soil-water ratio 1:2.5, potentiometric method); calcium carbonate content = 5.8% (gas volume method); organic matter = 12.5 g / kg (potassium dichromate external heating method); DTPA available zinc = 0.48 mg / kg (extraction-atomic absorption method).
[0079] The test crop was maize (Zea mays L.), variety "Zhengdan 958". The seeds were disinfected with 1% sodium hypochlorite, washed with water, and germinated at 28°C until they showed white sprouts.
[0080] Test methods 1. Soil culture experiment (testing the stability of zinc speciation) Culture setup: Weigh 200 g of air-dried soil into a 250 mL polyethylene plastic bottle, accurately add the fertilizer for each treatment at a dosage of 20 mg Zn / kg soil, and mix thoroughly. Adjust the soil moisture content to 65% of field capacity with deionized water. Punch holes in the bottle cap to ensure ventilation.
[0081] Culture conditions: Placed in a constant temperature incubator and cultured in the dark at 25 ± 1°C. A weighing method was used, with water added every 3 days to maintain a constant weight.
[0082] Sampling and determination: Destructive sampling was performed on days 1, 7, 30, 60, and 90 after culture. The samples were air-dried and then sieved through a 1 mm sieve.
[0083] Available zinc: DTPA extractant (0.005 M DTPA + 0.01 M CaCl2 + 0.1 M TEA, pH 7.3), soil-to-liquid ratio 1:2, shake for 2 hours, filter and determine by atomic absorption spectrometry.
[0084] Zinc speciation: A modified Tessier sequential extraction method was used to extract exchangeable zinc (1M MgCl2, pH 7.0), carbonate-bound zinc (1M NaOAc, pH 5.0), iron-manganese oxide-bound zinc (0.04M NH2OH·HCl in 25% HOAc), organically bound zinc (0.02M HNO3 + 30% H2O2, then 3.2M NH4OAc in 20% HNO3), and residual zinc (HClO4-HF digestion). The content of each speciation was determined by atomic absorption spectrometry.
[0085] 2. Potted biological experiment (testing the bioavailability of zinc) Potting setup: Use flowerpots with drainage holes (18 cm high, 16 cm in diameter), and fill each pot with 2.0 kg of the pretreated soil described above. Fertilizer was mixed with the soil, and the zinc application rate was the same as in the culture experiment (20 mg / kg). A blank control (CK) without zinc fertilizer was included. Each treatment had 6 replicates arranged in a completely randomized block design.
[0086] Planting and Management: Sow 5 pre-germinated seeds per pot, and thin to 2 seedlings per pot after emergence. Place in a greenhouse with day / night temperatures controlled at 28±3℃ / 20±2℃ and natural light. Use a weighing method to replenish deionized water daily, maintaining soil moisture content at 70%-75% of field capacity. Do not apply any additional fertilizer.
[0087] Harvesting and Measurement: Sixty days after planting, the above-ground parts of the plants were cut at ground level. The samples were blanched at 105℃ for 30 minutes, then dried at 75℃ to constant weight, and the dry weight was measured. The dried samples were digested by HNO3-HClO4 (5:1, v / v) using a wet digestion method, and the total zinc content was determined by atomic absorption spectrometry.
[0088] calculate: Total zinc uptake by the plant (μg / pot) = Dry weight of the plant (g / pot) × Zinc content of the plant (mg / kg) Zinc utilization rate (%) = [(Total zinc uptake by zinc-treated plants - Total zinc uptake by control plants) / Total zinc applied] × 100% 3. Test results (as shown in Table 1-3) Table 1: Dynamic changes in available zinc content of DTPA under different treatments during soil incubation (mg / kg)
[0089] While the initial available zinc content of this invention (F-Complete) is not the highest, its rate of decline is the slowest, and it remains the most stable. By 90 days, its available zinc content is 7.8 times that of zinc sulfate treatment, demonstrating excellent anti-fixation and long-lasting effects.
[0090] Table 2: Distribution of chemical forms of zinc in soil after 90 days of incubation (mg / kg)
[0091] Table 3: Zinc absorption and utilization of potted maize after 60 days of growth
[0092] As shown in Tables 2-3, the technical solution of the present invention (F-Complete) can significantly slow down the decay of zinc availability in calcareous soil through the synergistic effect of compound chelation, microbial activation and slow-release coating (the effective zinc retention after 90 days is 7.7 times that of the control) and increase the bioavailability of zinc to more than 3.3 times that of traditional zinc sulfate.
[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A zinc-rich organic fertilizer, characterized in that, The components include the following parts by mass: The ingredients include 40-60 parts organic substrate, 5-8 parts composite zinc source, 3-5 parts composite chelating agent, 2-3 parts functional microbial agent, 0.3-0.5 parts magnesium sulfate, 0.2-0.3 parts manganese sulfate, 0.2-0.3 parts boric acid, 0.1-0.2 parts ammonium molybdate, 2-4 parts slow-release coating agent, and 1-2 parts zeolite powder.
2. The zinc-rich organic fertilizer according to claim 1, characterized in that, The method for preparing the organic substrate is as follows: After crushing the livestock and poultry manure, add water at a solid-liquid ratio of 1:5, stir to form a slurry, and adjust the pH to 6.5-7.0 to obtain the livestock and poultry manure slurry. The aminophosphonic acid chelating resin was activated by soaking in 5% hydrochloric acid solution for 2 hours, washed with water until neutral, and then packed into the adsorption column. The livestock and poultry manure slurry was added to an adsorption column and adsorbed at room temperature until the zinc content of the effluent was ≤50mg / kg. The adsorption was then stopped to obtain pretreated livestock and poultry manure. The pretreated livestock and poultry manure, crop straw, and kitchen waste fermentation residue are mixed in a mass ratio of 2:1:1 to obtain an organic substrate.
3. The method for preparing a zinc-rich organic fertilizer according to claim 2, characterized in that, The composite zinc source is composed of zinc sulfate and zinc oxide in a mass ratio of 1:1; the composite chelating agent is composed of modified humic acid and tea polyphenols in a mass ratio of 3:
2.
4. The method for preparing a zinc-rich organic fertilizer according to claim 3, characterized in that, The modified humic acid is prepared by: Humic acid powder and water were mixed in a mass ratio of 1:3 and stirred to form a suspension. The pH was adjusted to 2.0-2.5 with 10% hydrochloric acid solution. The mixture was stirred at room temperature for 30 minutes. After filtration, the filter cake was collected and washed with water until the pH of the filtrate was ≥4.
0. The filtrate was dried in an oven at 80℃ to constant weight to obtain pretreated humic acid. The pretreated humic acid was added to water at a solid-liquid ratio of 1:10, and the temperature was raised to 50°C. 20% of the mass of the pretreated humic acid in a 30% hydrogen peroxide solution was added dropwise. After the addition was completed, the temperature was raised to 60°C and stirred at a constant temperature for 2 hours. After the addition was completed, the pH of the reaction solution was adjusted to 6.0-6.5 with a 10% sodium hydroxide solution. The mixture was allowed to stand for 4 hours to precipitate, and the filter cake was collected by filtration. The cake was washed three times with water and vacuum dried at 80°C and -0.08 MPa until the moisture content was 10%. The cake was then pulverized to 200 mesh to obtain the modified humic acid.
5. The method for preparing a zinc-rich organic fertilizer according to claim 4, characterized in that, The functional microbial agent is composed of *Priscilla auriculata* and *Bacillus subtilis* at a live bacteria ratio of 2:
1.
6. The method for preparing a zinc-rich organic fertilizer according to claim 5, characterized in that, The sustained-release coating agent is a mixture of starch and chitosan in a mass ratio of 4:
1.
7. A method for preparing a zinc-rich organic fertilizer as described in any one of claims 1-6, characterized in that, The preparation steps include the following: The composite zinc source was added to water, stirred and dissolved, and the pH was adjusted to 5.0-5.5 to obtain a composite zinc source solution. The composite chelating agent is added to the composite zinc source solution for chelation treatment to obtain a chelated zinc concentrate. The organic substrate is mixed with zeolite powder and then fermented in stages. During the fermentation, the chelated zinc concentrate and functional microbial agent are added. After the fermentation is completed, magnesium sulfate, manganese sulfate, boric acid and ammonium molybdate are added and stirred to obtain the fermented material. After the fermentation material is coated with the slow-release coating agent, the zinc-rich organic fertilizer is obtained.
8. The method for preparing a zinc-rich organic fertilizer according to claim 7, characterized in that, The chelation treatment specifically involves: stirring at a constant temperature of 55°C for 3 hours, followed by vacuum concentration until the solid content reaches 40%.
9. The method for preparing a zinc-rich organic fertilizer according to claim 7, characterized in that, The segmented fermentation specifically refers to: The organic substrate was mixed with zeolite powder and fermented at 55-65℃ for 7 days, during which time it was fed with a 0.4m... 3 / (m 3 Air is introduced at a rate of h), and after the fermentation is completed, the fermentation temperature is lowered to 30-35℃. The chelated zinc concentrate is then sprayed and stirred. After spraying, the functional microbial agent is inoculated and sealed for anaerobic fermentation for 9 days.
10. The method for preparing a zinc-rich organic fertilizer according to claim 8, characterized in that, The sustained-release coating specifically refers to: The slow-release coating agent was dissolved in a 5% acetic acid solution at a solid-liquid ratio of 1:10 to obtain a coating solution. The fermented material was pulverized and sprayed with the coating solution. After spraying, it was dried at a low temperature of 50°C for 2.5 hours.