Application of method for preparing functional biological flora in coupling mode of targeted biological flora and host original flora in sweet potato root rot prevention and control and heavy metal and pesticide residue treatment

Abstract

The invention discloses application of a method for preparing a functional biological flora in a targeted biological flora and host original flora coupling mode in sweet potato root rot control and heavy metal and pesticide residue treatment, and is characterized in that the functional biological flora obtained through coupling culture is prepared into a microbial agent or a water-soluble fertilizer for sweet potato cultivation; the invention relates to the technical field of agricultural biological treatment.The flora design integrates the functions of antagonism, growth promotion, heavy metal passivation, pesticide residue degradation and the like, the synergistic effect of disease prevention and control, quality improvement and residue reduction is achieved, and through coupling culture with sweet potato host original flora, the sweet potato root rot damage and heavy metal and pesticide residue exceeding are achieved. The planting capacity and the survival rate of the functional flora in the sweet potato rhizosphere are remarkably improved, it is ensured that the functional flora plays a role permanently and stably, and the combined action of the functional flora and the organic carrier can improve the soil aggregate structure, improve the nutrient utilization rate and restore the micro-ecological environment.

Description

Application of a method for preparing functional microbial communities by coupling targeted microorganisms with the host's original microbial community in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues. Technical Field

[0001] This invention relates to the fields of agricultural biotechnology and integrated crop disease management, specifically to the application of a method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbial community in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues. Background Technology

[0002] Sweet potatoes are an important food, feed, and economic crop in my country, but they are generally affected by root rot and quality and safety issues caused by heavy metals and pesticide residues in the soil during production.

[0003] 1. Root rot is a serious disease caused by various pathogens, including Fusarium, resulting in root rot, seedling death, severe yield reduction, and even crop failure. Chemical pesticides have limited effectiveness and are prone to causing residues and resistance.

[0004] 2. Excessive heavy metals and pesticide residues: Heavy metals (such as cadmium, lead, and arsenic) and persistent pesticides in the soil can be accumulated in sweet potatoes, threatening food safety.

[0005] 3. Limitations of existing technology: Most existing microbial agents have a single function, focusing either on disease prevention or soil remediation. There is a lack of compound microbial solutions that can systematically and synergistically solve the three core problems of diseases, heavy metals, and pesticide residues in sweet potato production.

[0006] Therefore, developing a multifunctional composite microbial community and its application method that can simultaneously prevent and control sweet potato root rot, inhibit heavy metal absorption, and degrade pesticide residues is of great significance for ensuring the healthy development of the sweet potato industry. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbial community, and to apply this method to the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, thereby solving the aforementioned problems existing in the prior art.

[0008] The technical solution of this invention to achieve the above objectives is as follows: a method for preparing functional microbial communities through a targeted coupling of microorganisms with the original host microbial community, applied to the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues. The functional microbial communities obtained through coupled culture are prepared into microbial agents or water-soluble fertilizers for sweet potato cultivation, synergistically addressing the problems of sweet potato root rot damage and excessive heavy metal and pesticide residues. This invention utilizes targeted screening of multi-strain bacteria with functions including antagonizing root rot pathogens, passivating heavy metals, degrading pesticide residues, and promoting growth. These strains are coupled and symbiotically cultured with the original host microbial community of the sweet potato rhizosphere, enhancing the compatibility and environmental adaptability of the microbial community. The functional microbial communities, combined with an optimized nutrient carrier and auxiliary components, can inhibit root rot pathogens through antagonistic strains, reduce heavy metal and pesticide residue content through passivating / degrading strains, and improve sweet potato growth performance through growth-promoting strains and nutrients, achieving multiple objectives synergistically. The application effect is stable and reliable. Optionally, the preparation method of the functional microbial community includes the following steps: a. constructing a targeted microbial strain resource library and screening single strains with functions such as antagonizing root rot pathogens, passivating heavy metals, degrading pesticide residues, and promoting growth; b. purifying and compounding the single strains; c. coupling and symbiotically culturing the compound microbial community with the host original microbial community extracted from the rhizosphere soil of healthy sweet potatoes; d. mixing the coupled cultured compound microbial community with a nutrient carrier and auxiliary components to prepare a microbial agent or water-soluble fertilizer. Through the process of "screening-purification and compounding-coupled culture-formulation preparation", the functional diversity and activity stability of the functional microbial community are ensured. The introduction of the host original microbial community enhances the colonization ability of the compound microbial community in the rhizosphere of sweet potatoes and avoids the rejection effect between exogenous microbial communities and soil microecology. Optionally, the single strains screened in step a may include: core antagonistic bacteria: Trichoderma harzianum and Trichoderma viride; competitive colonization and antibacterial bacteria: Bacillus subtilis and Bacillus amyloliquefaciens; growth-promoting and repairing bacteria: Bacillus jellyoidus; heavy metal passivation and pesticide residue degradation bacteria: Bacillus laterosporus and Pseudomonas fluorescens; wherein at least four strains are included: Trichoderma harzianum, Bacillus subtilis, Bacillus jellyoidus, and Bacillus laterosporus. The combined strains exhibit complementary functions and significant synergistic effects: *Trichoderma harzianum* and *Trichoderma viride* inhibit the growth of sweet potato root rot pathogens by producing antibacterial substances and competing for nutrient space, providing long-lasting protection; *Bacillus subtilis* and *Bacillus amyloliquefaciens* can form biofilms on the surface of sweet potato roots, enhancing competitive colonization and further inhibiting pathogen infection, while also secreting proteases and cellulases to promote the degradation of organic matter; *Bacillus spp.* can activate nutrients such as phosphorus and potassium in the soil and secrete growth-promoting substances such as auxins and gibberellins to promote sweet potato root development and plant growth; *Bacillus lateralis* and *Pseudomonas fluorescens* can passivate heavy metals by producing organic acids and chelating agents, reducing their bioavailability, while also degrading common pesticide residues such as organophosphates and pyrethroids; the mandatory inclusion of the four core strains ensures the basic functions of disease control, pollution control, and growth promotion, while the addition of other strains further enhances the synergistic effect.Optionally, the concentration of each strain in the functional microbial community is: Trichoderma harzianum ≥ 2.0 × 10⁻⁶. 8 CFU / g or ml, Trichoderma viride ≥1.5×10 8 CFU / g or ml, Bacillus subtilis ≥5.0×10⁻⁶ 8 CFU / g or ml, Bacillus amyloliquefaciens ≥3.0×10⁻⁶ 8 CFU / g or mL, gelatinous Bacillus ≥1.0×10 8 CFU / g or ml, Bacillus retrosporum ≥2×10 8 CFU / g or mL, ≥1×10⁻⁶ CFU / g or mL, Pseudomonas fluorescens ≥1×10⁻⁶ 8 CFU / g or ml, host original flora ≥1×10 8 CFU / g or ml. The minimum concentration standard for each strain is clearly defined to ensure that the functional microbial community possesses sufficient antagonistic activity, passivation / degradation ability, and growth-promoting effect, avoiding a decrease in application effectiveness due to insufficient strain concentration. Controlling the concentration of the original host microbial community ensures a balanced symbiotic relationship between it and the compound microbial community, improving the overall colonization stability of the composite microbial community. Optionally, the nutrient carrier and auxiliary components mentioned in step d include potassium humate, seaweed polysaccharides, amino acid chelated trace elements, potassium dihydrogen phosphate, natural organic acid complexes, molasses or sucrose, and fillers. Nutrient carriers and auxiliary components are functionally adapted: humic acid and potassium fulvate improve soil structure, promote microbial reproduction and colonization, and enhance soil water and fertilizer retention capacity; seaweed polysaccharides enhance sweet potato's resistance to stress (drought, salt, and disease) while providing a carbon source for microbial growth; amino acid chelated trace elements (such as chelated iron, zinc, and copper) are easily absorbed by sweet potatoes, supplementing the trace elements needed for growth and synergistically promoting growth performance of the growth-promoting strains; potassium dihydrogen phosphate provides phosphorus and potassium nutrition, promoting sweet potato tuber enlargement and quality improvement; natural organic acid complexes (such as citric acid and malic acid complexes) enhance the passivation effect of heavy metals while regulating soil pH; molasses or sucrose provides a fast-acting carbon source for microbial growth and maintains microbial activity; fillers (such as diatomaceous earth and vermiculite) are used to regulate the physical properties of the microbial agent, facilitating storage and application. Optionally, each ton of finished product may contain the following components: 30-50 kg of potassium humate, 10-30 kg of seaweed polysaccharide, 5-15 kg of amino acid chelated trace elements, 10-20 kg of potassium dihydrogen phosphate, 20-40 kg of natural organic acid complex, 5-15 kg of molasses or sucrose, with the remainder being filler.

[0009] The dosage range of each ton of finished product is clearly defined to ensure that the nutrient supply matches the activity requirements of the microbial community, avoiding the impact of excessive or insufficient components on the application effect. The dosage range is set to take into account the degree of soil pollution in different planting areas and the differences in sweet potato varieties, improving product adaptability and application flexibility. Optionally, the application can reduce the incidence of sweet potato root rot by more than 30%, reduce the residues of heavy metals cadmium, lead, and arsenic in sweet potato tubers by more than 25%, reduce the residues of common pesticides by more than 30%, and increase sweet potato yield by more than 10%. This invention also proposes a compound microbial agent for the prevention and control of sweet potato root rot and the treatment of heavy metals and pesticide residues.

[0010] This compound microbial agent is formulated by combining the functional microbial community obtained above with nutrient carriers and auxiliary components. It integrates the synergistic effect of the functional microbial community with the auxiliary function of the nutrient carrier. It is available in solid granular form (inoculant) or liquid form (water-soluble fertilizer). The solid inoculant is convenient for basal application or hole application in the soil, while the water-soluble fertilizer is convenient for fertigation or drip irrigation. It is flexible and convenient to use and can be directly applied to the cultivation and management of sweet potatoes at different growth stages. This invention also proposes a cultivation method for preventing sweet potato root rot and reducing heavy metal and pesticide residues. The above-mentioned compound microbial agent or the water-soluble fertilizer prepared from it is applied during the seedling stage, transplanting stage, and critical growth stage of sweet potatoes. Targeting the growth and development patterns of sweet potatoes, precise application during disease-susceptible periods (seedling stage, transplanting stage) and critical periods of pollutant accumulation (critical growth stage) ensures timely establishment and effectiveness of the microbial community. The synergistic effect of nutrients and functional strains enhances the prevention and control effect and pollution control efficiency. The operation is simple and easy for farmers to master and promote.

[0011] The beneficial effects of this invention are: 1. Multifunctional synergy: The microbial community design integrates functions such as antagonism (Trichoderma, Bacillus), growth promotion (gelatinous Bacillus), heavy metal passivation (Bacillus lateralis), and pesticide residue degradation (Pseudomonas fluorescens), achieving a synergistic effect of disease control, quality improvement and residue reduction.

[0012] 2. Strong ecological adaptability: Through coupled culture with the original microbial community of sweet potato host, the colonization ability and survival rate of functional microbial community in sweet potato rhizosphere are significantly improved, ensuring its long-term and stable function.

[0013] 3. Safe and efficient: It controls root rot through microbial antagonism, competition and hyperparasitism; reduces the effectiveness of heavy metals through microbial passivation and chelation; and reduces pesticide residues through microbial degradation, thus achieving green prevention and control and quality improvement.

[0014] 4. Soil improvement: The combined action of functional microbial communities and organic carriers can improve soil aggregate structure, increase nutrient utilization, and restore the micro-ecological environment. Detailed Implementation

[0015] To better explain and facilitate understanding of this invention, a detailed description of the invention is provided below in conjunction with specific embodiments. The functional microbial community application technology proposed in this invention, which couples targeted microorganisms with the host's original microbial community, achieves synergistic goals of sweet potato root rot prevention, heavy metal and pesticide residue control, and yield improvement through precise strain screening, optimized coupling culture processes, matching nutrient carriers and auxiliary components, and targeted cultivation methods. The technical solution is reproducible and scalable. To better understand the above technical solution, exemplary embodiments of the invention will be described in detail below. While exemplary embodiments of the invention are shown, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a clearer and more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. Embodiments

[0016] Preparation and application of compound microbial agents for sweet potatoes 1. Activation and propagation of strains: The original strains of Trichoderma harzianum, Trichoderma viride, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus jellyoidis, Bacillus breviculatus, and Pseudomonas fluorescens were activated separately and fermented at high density.

[0017] 2. Extraction of original host microbiota: Samples were collected from the rhizosphere soil of healthy sweet potatoes, and the original host microbiota specific to sweet potato rhizosphere was obtained through enrichment culture and purification.

[0018] 3. Coupling symbiotic culture: The individual strains obtained in step 1 are mixed in a specific ratio, with the ratio of Trichoderma:Bacillus:Others approximately 3.5:8:1.5 based on the number of CFU. Then, they are mixed with the original host flora obtained in step 2 at a volume ratio of 10:1 and co-cultured under suitable conditions for 48 hours to form a stable composite functional flora.

[0019] 4. Formulation preparation: Mix the concentrated liquid or cells of the coupled-cultured compound functional bacterial group with the following ingredients to make a wettable powder or high-concentration liquid: humic acid potassium fulvate: 40 kg, seaweed polysaccharide: 20 kg, amino acid chelated trace elements: 10 kg, potassium dihydrogen phosphate: 15 kg, natural organic acid complex: 30 kg, molasses: 10 kg, diatomaceous earth / light calcium carbonate: balance, make up to 1 ton to ensure that the concentration of each functional bacteria in the finished product meets the requirements.

[0020] Field Application: Following the methods in the "Sweet Potato Root Rot Compound Microbial Agent Formulation and Usage Manual," this agent was applied during sweet potato seedling raising (seedbed treatment, seedling root dipping), transplanting (soil basal application, root watering), and key growth stages (preventive and therapeutic root irrigation). Practice has shown that this application effectively controls root rot, reduces heavy metal and pesticide residues in sweet potatoes, and improves yield and quality. Example

[0021] This embodiment provides the preparation and application of a second type of sweet potato-specific compound microbial agent. 1. Strain activation and propagation: The original strains of Trichoderma harzianum, Trichoderma viride, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus lentigines, Bacillus brevis, and Pseudomonas fluorescens are activated separately and subjected to high-density fermentation.

[0022] 2. Extraction of original host microbiota: Samples were collected from the rhizosphere soil of healthy sweet potatoes, and the original host microbiota specific to sweet potato rhizosphere was obtained through enrichment culture and purification.

[0023] 3. Coupling symbiotic culture: The individual strains obtained in step 1 are mixed in a specific ratio, with the ratio of Trichoderma:Bacillus:Others approximately 4:10:2.5 based on the number of CFU. Then, they are mixed with the original host flora obtained in step 2 at a volume ratio of 10:1 and co-cultured under suitable conditions for 60 hours to form a stable composite functional flora.

[0024] 4. Formulation Preparation: The concentrated solution or cells of the coupled-cultured compound functional bacterial community are uniformly mixed with the following components to prepare a wettable powder or high-concentration liquid: humic acid, potassium fulvate: 30 kg; seaweed polysaccharide: 10 kg; amino acid chelated trace elements: 5 kg; potassium dihydrogen phosphate: 10 kg; natural organic acid complex: 20 kg; molasses: 5 kg; diatomaceous earth / light calcium carbonate: balance, to a total of 1 ton. Example

[0025] Preparation and application of compound microbial agents for sweet potatoes 1. Activation and propagation of strains: The original strains of Trichoderma harzianum, Trichoderma viride, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus jellyoidis, Bacillus breviculatus, and Pseudomonas fluorescens were activated separately and fermented at high density.

[0026] 2. Extraction of original host microbiota: Samples were collected from the rhizosphere soil of healthy sweet potatoes, and the original host microbiota specific to sweet potato rhizosphere was obtained through enrichment culture and purification.

[0027] 3. Coupled symbiotic culture: The individual strains obtained in step 1 are mixed in a specific ratio, with the ratio of Trichoderma:Bacillus:Others ≈ 5:12:3 based on the number of CFU. Then, they are mixed with the original host flora obtained in step 2 at a volume ratio of 10:1 and co-cultured under suitable conditions for 72 hours to form a stable composite functional flora.

[0028] 4. Formulation preparation: Mix the concentrated liquid or cells of the coupled-cultured compound functional bacterial group with the following ingredients to make a wettable powder or high-concentration liquid: humic acid potassium fulvate: 50 kg, seaweed polysaccharide: 30 kg, amino acid chelated trace elements: 15 kg, potassium dihydrogen phosphate: 20 kg, natural organic acid complex: 40 kg, molasses: 15 kg, diatomaceous earth / light calcium carbonate: balance, make up to 1 ton to ensure that the concentration of each functional bacteria in the finished product meets the requirements.

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing functional microbial communities by coupling targeted microorganisms with the host's original microbial community, and its application in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, characterized in that, The functional microbial communities obtained from coupled culture are prepared into microbial agents or water-soluble fertilizers for sweet potato cultivation, in order to synergistically solve the problems of sweet potato root rot and excessive heavy metal and pesticide residues.

2. The method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbiota according to claim 1, and its application in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, is characterized in that... The method for preparing the functional microbial community includes the following steps: a. Constructing a targeted microbial strain resource library and screening single strains with functions such as antagonizing root rot pathogens, passivating heavy metals, degrading pesticide residues, and promoting growth; b. Purifying and compounding the single strains; c. Coupled symbiotic culture of the compound microbial community with the host original microbial community extracted from the rhizosphere soil of healthy sweet potatoes; d. Mixing the coupled cultured compound microbial community with nutrient carriers and auxiliary components to prepare microbial agents or water-soluble fertilizers.

3. The method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbiota according to claim 2, and its application in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, is characterized in that... The single strains screened in step a include: core antagonistic bacteria: Trichoderma harzianum and Trichoderma viride; competitive colonization and antibacterial bacteria: Bacillus subtilis and Bacillus amyloliquefaciens; growth-promoting and repairing bacteria: Bacillus jelly-like bacteria; heavy metal passivation and pesticide residue degradation bacteria: Bacillus laterosporus and Pseudomonas fluorescens; among them, at least four strains are included: Trichoderma harzianum, Bacillus subtilis, Bacillus jelly-like bacteria, and Bacillus laterosporus.

4. The method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbiota according to claim 3, and its application in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, is characterized in that... The concentration of each strain in the functional microbial community is: Trichoderma harzianum ≥ 2.0 × 10⁻⁶. 8 CFU / g or ml, Trichoderma viride ≥1.5×10 8 CFU / g or ml, Bacillus subtilis ≥5.0×10⁻⁶ 8 CFU / g or ml, Bacillus amyloliquefaciens ≥3.0×10⁻⁶ 8 CFU / g or mL, gelatinous Bacillus ≥1.0×10 8 CFU / g or ml, Bacillus retrosporum ≥2×10 8 CFU / g or mL, ≥1×10⁻⁶ CFU / g or mL, Pseudomonas fluorescens ≥1×10⁻⁶ 8 CFU / g or ml, host original flora ≥1×10 8 CFU / gram or milliliter.

5. The application of the method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbiota according to claim 2 in the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, characterized in that, The nutrient carrier and auxiliary components mentioned in step d include potassium humate, seaweed polysaccharides, amino acid chelated trace elements, potassium dihydrogen phosphate, natural organic acid complex, molasses or sucrose, and fillers.

6. The method for preparing functional microbial communities by coupling targeted microorganisms with the original host microbiota according to claim 5, applied to the prevention and control of sweet potato root rot and the treatment of heavy metal and pesticide residues, is characterized in that... The composition of the nutrient carrier and auxiliary components in each ton of finished product includes: 30-50 kg of potassium humate, 10-30 kg of seaweed polysaccharide, 5-15 kg of amino acid chelated trace elements, 10-20 kg of potassium dihydrogen phosphate, 20-40 kg of natural organic acid complex, 5-15 kg of molasses or sucrose, and the remainder is filler.

7. The application according to any one of claims 1-6, characterized in that, The application can reduce the incidence of sweet potato root rot by more than 30%, reduce the residues of heavy metals cadmium, lead, and arsenic in sweet potato tubers by more than 25%, reduce the residues of common pesticides by more than 30%, and increase sweet potato yield by more than 10%.

8. A compound microbial agent for the prevention and control of sweet potato root rot and the treatment of heavy metals and pesticide residues, characterized in that, It is a compound of functional microbial flora prepared by any one of claims 2-6, nutrient carriers, and auxiliary components.

9. A cultivation method for preventing and controlling sweet potato root rot and reducing heavy metal and pesticide residues, characterized in that, During the seedling stage, transplanting stage, and critical growth stage of sweet potatoes, apply the compound microbial agent as described in claim 8 or the water-soluble fertilizer prepared therefrom.