Bio-organic fertilizer with soil improvement and antagonistic soil-borne disease and preparation method and application thereof

Abstract

This invention discloses a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases, along with its preparation method and application, belonging to the field of bio-organic fertilizer technology. The bio-organic fertilizer of this invention comprises the following raw materials in parts by weight: 30-40 parts earthworm castings, 20-25 parts straw powder, 20-25 parts seaweed residue, 15-20 parts tea seed cake-biochar composite carrier, 4-6 parts compound microbial inoculant, 3-5 parts bitter melon extract, 2-3 parts *Streptomyces brevicornu* polysaccharide, and 5-8 parts soil conditioner. The compound microbial inoculant includes *Bacillus pyogenes* and *Streptomyces garneriensis*. This invention innovatively adds *Bacillus pyogenes*, *Streptomyces garneriensis*, and bitter melon extract to the bio-organic fertilizer. Combined with other organic matter, this reduces reliance on chemical fertilizers, aligning with the direction of green agriculture. This bio-organic fertilizer improves soil physicochemical properties and controls soil-borne diseases through multiple mechanisms, particularly exhibiting antagonistic effects against various potato soil-borne diseases, effectively preventing potato black scurf, scab, and wilt.

Description

Technical Field

[0001] This invention belongs to the field of bio-organic fertilizer technology, specifically relating to a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases, as well as its preparation method and application. Background Technology

[0002] Potatoes are a staple food crop, characterized by high yield and strong adaptability. Due to the robust development of the potato industry, demand and planting area have increased significantly. However, limited by factors such as limited per capita arable land and slow land turnover, most potato farmers choose continuous cropping. But long-term continuous cropping not only reduces potato yield and quality but also causes soil nutrient imbalances and decreased activity, among other problems. To address these issues, most farmers increase fertilizer and pesticide application. However, long-term, excessive fertilization and pesticide use not only reduces fertilizer and pesticide utilization and pollutes the farmland soil ecosystem but also leads to soil compaction, acidification, and deterioration of the microecological environment. Furthermore, the persistent threat of soil-borne diseases severely restricts sustainable development, with black sclerotium and scab being particularly prominent. These two diseases can reduce the marketable potato yield, resulting in significant yield losses. The sclerotia or scabs formed on the surface of diseased potatoes significantly reduce the appearance quality of the tubers, leading to a drop in market price.

[0003] Microbial fertilizers, as a novel biological agent in modern agriculture, derive their core function from the physiological metabolic processes of active microorganisms. These fertilizers provide essential nutrients to crops through the life activities of microorganisms. Their mechanism of action primarily involves microorganisms synthesizing antibiotics and inducing plants to produce systemic defense enzymes and other bioactive substances, thereby effectively controlling plant diseases caused by bacteria and fungi, reducing the harm of pathogenic microorganisms to crops, and enhancing the disease resistance of host plants. Therefore, the rational use of bio-organic fertilizers is an effective way to solve the problem of continuous cropping obstacles in potato production. Bio-organic fertilizers are rich in organic nutrients and microbial communities, and are characterized by being green and safe, with slow nutrient release. When applied to the soil, they can increase soil fertility, improve soil activity, reduce the risk of soil pollution, and promote green and sustainable agricultural development.

[0004] However, traditional bio-organic fertilizers still face some bottlenecks in practical applications: on the one hand, single-function microbial strains often have a narrow antibacterial spectrum, making it difficult to cope with complex soil-borne pathogen infections; on the other hand, the survival and colonization ability of microbial agents in the soil, as well as their competitive ability with native microorganisms, directly determine the stability and durability of their control effects. Furthermore, how to simultaneously and rapidly replenish soil organic matter, improve soil structure, and create a favorable soil environment through formula optimization is the core of improving the overall effectiveness of bio-organic fertilizers. Therefore, there is an urgent need to develop a new type of bio-organic fertilizer that can not only directly antagonize multiple soil-borne pathogens through highly efficient compound microbial agents, but also fundamentally improve the physical, chemical, and biological properties of the soil through scientifically formulated organic raw materials and functional adjuvants, achieving a comprehensive solution that addresses both the symptoms and the root cause. This requires focusing on the synergistic effects between strains when selecting functional microorganisms and exploring the interaction between natural plant active ingredients and microorganisms to develop a comprehensive solution that combines soil improvement with highly efficient antagonism of soil-borne diseases, providing strong support for the green and safe production of crops such as potatoes. Summary of the Invention

[0005] The purpose of this invention is to provide a bio-organic fertilizer that combines soil improvement and resistance to soil-borne diseases. This bio-organic fertilizer effectively improves the physical and chemical properties of the soil and effectively prevents and controls potato black scurf, potato scab, and potato wilt.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A bio-organic fertilizer that combines soil improvement and resistance to soil-borne diseases comprises the following raw materials in parts by weight: 30-40 parts earthworm castings, 20-25 parts straw powder, 20-25 parts seaweed residue, 15-20 parts tea seed cake-biochar composite carrier, 4-6 parts compound microbial inoculant, 3-5 parts bitter melon extract, 2-3 parts short-stem mold polysaccharide, and 5-8 parts soil conditioner.

[0008] Furthermore, the straw powder is pulverized through a 30-mesh sieve.

[0009] Furthermore, the compound microbial agent includes *Bacillus hygroscopicus* and *Streptomyces garnacanthus*; the strain number of *Bacillus hygroscopicus* is CGMCC 1.12171, purchased from the China General Microbiological Culture Collection Center, with an original deposit date of February 14, 2012; the strain number of *Streptomyces garnacanthus* is CGMCC 4.1967, purchased from the China General Microbiological Culture Collection Center, with an original deposit date of August 10, 2004. All strains used in this invention can be publicly purchased through the strain catalog of the China General Microbiological Culture Collection Center, eliminating the need for repeated biological preservation.

[0010] Furthermore, the preparation method of the aforementioned compound microbial agent is as follows:

[0011] S1: After activating Bacillus cereus, single colonies were picked and cultured in nutrient broth at 30°C for 48 hours. The culture was then inoculated into a fermenter at 10% of the amount in the seed culture medium and cultured until the bacterial concentration reached OD500. 600 =3.0 yielded Bacillus hygroscopicus bacterial culture;

[0012] S2: After activating *Streptomyces garneri*, add 0.5 ml of the bacterial suspension to ISP-2 agar medium and incubate at 28°C for 5 days. Scrape off pea-sized mycelia and spores and inoculate them into ISP-2 liquid medium, shaking for 24-48 hours to obtain the seed culture. Inoculate 10% of the seed culture into a fermenter and incubate until the bacterial concentration reaches OD500. 600 =3.0 yielded Ghanaian Streptomyces bacterial solution;

[0013] S3: Mix the two bacterial solutions obtained at a volume ratio of 1:1, freeze-dry them into freeze-dried powder, and obtain a compound microbial agent.

[0014] Furthermore, the preparation method of the tea seed cake-biochar composite carrier is as follows:

[0015] (1) Biochar preparation: Dry the tea seed shells until the moisture content is less than 15%, crush them into particles of 0.5-2cm, put the raw materials into a muffle furnace, raise the temperature to 400-500℃ under a nitrogen atmosphere, maintain for 1-2h, cool to room temperature after carbonization, and crush into particles with a particle size of 0.5-1mm.

[0016] (2) Pretreatment of tea seed cake: Mix tea seed cake powder, water and EM bacterial solution evenly, pile them up and ferment for 15 days;

[0017] (3) Construction of composite carrier: Biochar and pretreated tea seed dry matter are mixed evenly at a mass ratio of 3:1. The mixed material is piled up for 24-48 hours and dried in a ventilated environment at 40℃ to reduce the moisture content to 10% to obtain tea seed-biochar composite carrier.

[0018] 5. The bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases according to claim 1 is characterized in that the mass ratio of tea seed cake powder to water in step (2) is 1:0.8, and the amount of EM bacterial solution added is 1.5% of the mass of tea seed cake powder.

[0019] Furthermore, the soil conditioner comprises calcined potassium feldspar powder and diatomaceous earth in a mass ratio of 1:2.

[0020] A method for preparing a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases includes the following steps:

[0021] First, prepare a compound microbial inoculant and a tea seed cake-biochar composite carrier. Then, mix earthworm castings, straw powder, seaweed residue, tea seed cake-biochar composite carrier, compound microbial inoculant, bitter melon extract, short-stem mold polysaccharide, and soil conditioner evenly using a mechanical mixer to obtain the final product, bio-organic fertilizer.

[0022] The application of a bio-organic fertilizer that combines soil improvement and resistance to soil-borne diseases. The bio-organic fertilizer is used to improve the soil and effectively prevent and control potato black scurf, potato scab and potato wilt.

[0023] All raw materials used in this invention are commercially available.

[0024] This invention incorporates *Bacillus hygroscopicus* and *Streptomyces garneri*. *Bacillus hygroscopicus* produces antibiotics that directly kill pathogens and reproduces rapidly, quickly seizing living space and nutrients around the rhizosphere, effectively inhibiting pathogen survival and preventing them from colonizing and infecting plant roots. It also activates the plant's own defense system, allowing for a faster and stronger response when pathogens attack. Furthermore, its secreted enzymes accelerate the decomposition of organic matter in organic fertilizers, converting it into smaller molecules that are more easily absorbed by plants. *Bacillus hygroscopicus* can activate insoluble phosphorus and potassium elements in the soil, converting them into readily available nutrients for crop absorption. *Streptomyces garneri* produces a variety of highly effective antibiotics with strong inhibitory effects on a wide range of soil-borne pathogens and exhibits strong survival and colonization capabilities in the soil, providing relatively long-lasting protection. In addition, the mycelium of *Streptomyces garneri* helps form soil aggregates, enhancing soil aeration and water and fertilizer retention capacity. It can also decompose cellulose, which is crucial for converting straw into humus and improving soil fertility. The two work together to accelerate the decomposition and nutrient release of organic fertilizer, while preventing and controlling diseases, truly achieving the triple purpose of nourishing the soil, preventing diseases, and promoting growth.

[0025] Bitter melon extract mainly contains momordicin, momordicin, and flavonoids. Momordicin effectively inhibits the growth of Rhizoctonia solani. Flavonoids, including rutin, quercetin, and catechins, are abundant in bitter melon and their antioxidant capacity helps plants resist oxidative stress caused by diseases, drought, and other adverse conditions, thus enhancing plant resilience. Polysaccharides are also present in the extract. Polysaccharides are excellent food sources for beneficial microorganisms in the soil and are crucial for improving soil microbial communities.

[0026] Beneficial effects

[0027] This invention's bio-organic fertilizer innovatively incorporates Bacillus hygroscopicus, Streptomyces galbana, and bitter melon extract. When combined with other ingredients, it can reduce reliance on chemical fertilizers, aligning with the direction of green agriculture.

[0028] The bio-organic fertilizer of this invention improves the physical and chemical properties of soil and controls a variety of diseases through multiple mechanisms. Both strains have antagonistic effects on soil-borne diseases of potatoes and effectively prevent and control potato black scurf, scab and wilt. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0030] Example 1

[0031] A bio-organic fertilizer that combines soil improvement and resistance to soil-borne diseases comprises the following raw materials in parts by weight: 30 parts earthworm castings, 20 parts straw powder, 20 parts seaweed residue, 15 parts tea seed cake-biochar composite carrier, 4 parts compound microbial inoculant, 3 parts bitter melon extract, 2 parts short-stem mold polysaccharide, and 5 parts soil conditioner.

[0032] The compound microbial agent includes Bacillus hygroscopicus and Streptomyces garnacanum; the strain number of Bacillus hygroscopicus is CGMCC 1.12171; the strain number of Streptomyces garnacanum is CGMCC 4.1967.

[0033] The preparation method of the aforementioned compound microbial agent is as follows:

[0034] S1: After activating Bacillus cereus, single colonies were picked and cultured in nutrient broth at 30°C for 48 hours. The culture was then inoculated into a fermenter at 10% of the amount in the seed culture medium and cultured until the bacterial concentration reached OD500. 600 =3.0 yielded Bacillus hygroscopicus bacterial culture;

[0035] S2: After activating *Streptomyces garneri*, add 0.5 ml of the bacterial suspension to ISP-2 agar medium and incubate at 28°C for 5 days. Scrape off pea-sized mycelia and spores and inoculate them into ISP-2 liquid medium, shaking for 24 hours to obtain the seed culture. Inoculate 10% of the seed culture into a fermenter and incubate until the bacterial concentration reaches OD500. 600 =3.0 yielded Ghanaian Streptomyces bacterial solution;

[0036] S3: Mix the two bacterial solutions obtained at a volume ratio of 1:1, freeze-dry them into freeze-dried powder, and obtain a compound microbial agent.

[0037] The preparation method of the tea seed cake-biochar composite carrier is as follows:

[0038] (1) Biochar preparation: The tea seed shells are dried to a moisture content of less than 15%, crushed into particles of 0.5-2cm, and the raw materials are placed in a muffle furnace. The temperature is raised to 400℃ under a nitrogen atmosphere and maintained for 2 hours. After carbonization, the temperature is cooled to room temperature and crushed into particles with a particle size of 0.5-1mm.

[0039] (2) Pretreatment of tea seed cake: Mix tea seed cake powder, water and EM bacterial solution evenly, pile them up and ferment for 15 days;

[0040] (3) Construction of composite carrier: Biochar and pretreated tea seed dry matter were mixed evenly at a mass ratio of 3:1. The mixed material was piled up for 24 hours and dried in a ventilated environment at 40°C to reduce the moisture content to 10% to obtain tea seed dry matter-biochar composite carrier.

[0041] In step (2), the mass ratio of tea seed cake powder to water is 1:0.8, and the amount of EM bacterial solution added is 1.5% of the mass of tea seed cake powder.

[0042] The soil conditioner comprises calcined potassium feldspar powder and diatomaceous earth in a mass ratio of 1:2.

[0043] A method for preparing a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases includes the following steps:

[0044] First, prepare a compound microbial inoculant and a tea seed cake-biochar composite carrier. Then, mix earthworm castings, straw powder, seaweed residue, tea seed cake-biochar composite carrier, compound microbial inoculant, bitter melon extract, short-stem mold polysaccharide, and soil conditioner evenly using a mechanical mixer to obtain the final product, bio-organic fertilizer.

[0045] Example 2

[0046] A bio-organic fertilizer that combines soil improvement and resistance to soil-borne diseases comprises the following raw materials in parts by weight: 35 parts earthworm castings, 23 parts straw powder, 22 parts seaweed residue, 17 parts tea seed cake-biochar composite carrier, 5 parts compound microbial inoculant, 4 parts bitter melon extract, 3 parts short-stem mold polysaccharide, and 7 parts soil conditioner.

[0047] The compound microbial agent includes Bacillus hygroscopicus and Streptomyces garnacanum; the strain number of Bacillus hygroscopicus is CGMCC 1.12171; the strain number of Streptomyces garnacanum is CGMCC 4.1967.

[0048] The preparation method of the aforementioned compound microbial agent is as follows:

[0049] S1: After activating Bacillus cereus, single colonies were picked and cultured in nutrient broth at 30°C for 48 hours. The culture was then inoculated into a fermenter at 10% of the amount in the seed culture medium and cultured until the bacterial concentration reached OD500. 600 =3.0 yielded Bacillus hygroscopicus bacterial culture;

[0050] S2: After activating *Streptomyces garneri*, add 0.5 ml of the bacterial suspension to ISP-2 agar medium and incubate at 28°C for 5 days. Scrape off pea-sized mycelia and spores and inoculate them into ISP-2 liquid medium, shaking for 36 hours to obtain the seed culture. Inoculate 10% of the seed culture into a fermenter and incubate until the bacterial concentration reaches OD500. 600 =3.0 yielded Ghanaian Streptomyces bacterial solution;

[0051] S3: Mix the two bacterial solutions obtained at a volume ratio of 1:1, freeze-dry them into freeze-dried powder, and obtain a compound microbial agent.

[0052] The preparation method of the tea seed cake-biochar composite carrier is as follows:

[0053] (1) Biochar preparation: The tea seed shells are dried to a moisture content of less than 15%, crushed into particles of 0.5-2cm, and the raw materials are placed in a muffle furnace. The temperature is raised to 450℃ under a nitrogen atmosphere and maintained for 1.5h. After carbonization, the temperature is cooled to room temperature and crushed into particles with a particle size of 0.5-1mm.

[0054] (2) Pretreatment of tea seed cake: Mix tea seed cake powder, water and EM bacterial solution evenly, pile them up and ferment for 15 days;

[0055] (3) Construction of composite carrier: Biochar and pretreated tea seed dry matter were mixed evenly at a mass ratio of 3:1. The mixed material was piled up for 36 hours and dried in a ventilated environment at 40°C to reduce the moisture content to 10% to obtain tea seed-biochar composite carrier.

[0056] In step (2), the mass ratio of tea seed cake powder to water is 1:0.8, and the amount of EM bacterial solution added is 1.5% of the mass of tea seed cake powder.

[0057] The soil conditioner comprises calcined potassium feldspar powder and diatomaceous earth in a mass ratio of 1:2.

[0058] A method for preparing a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases includes the following steps:

[0059] First, prepare a compound microbial inoculant and a tea seed cake-biochar composite carrier. Then, mix earthworm castings, straw powder, seaweed residue, tea seed cake-biochar composite carrier, compound microbial inoculant, bitter melon extract, short-stem mold polysaccharide, and soil conditioner evenly using a mechanical mixer to obtain the final product, bio-organic fertilizer.

[0060] Example 3

[0061] A bio-organic fertilizer that combines soil improvement and resistance to soil-borne diseases comprises the following raw materials in parts by weight: 40 parts earthworm castings, 25 parts straw powder, 25 parts seaweed residue, 20 parts tea seed cake-biochar composite carrier, 6 parts compound microbial inoculant, 5 parts bitter melon extract, 3 parts short-stem mold polysaccharide, and 8 parts soil conditioner.

[0062] The compound microbial agent includes Bacillus hygroscopicus and Streptomyces garnacanum; the strain number of Bacillus hygroscopicus is CGMCC 1.12171; the strain number of Streptomyces garnacanum is CGMCC 4.1967.

[0063] The preparation method of the aforementioned compound microbial agent is as follows:

[0064] S1: After activating Bacillus cereus, single colonies were picked and cultured in nutrient broth at 30°C for 48 hours. The culture was then inoculated into a fermenter at 10% of the amount in the seed culture medium and cultured until the bacterial concentration reached OD500. 600 =3.0 yielded Bacillus hygroscopicus bacterial culture;

[0065] S2: After activating *Streptomyces garneri*, add 0.5 ml of the bacterial suspension to ISP-2 agar medium and incubate at 28°C for 5 days. Scrape off pea-sized mycelia and spores and inoculate them into ISP-2 liquid medium, shaking and incubating for 48 hours to obtain the seed culture. Inoculate 10% of the seed culture into a fermenter and incubate until the bacterial concentration reaches OD500. 600 =3.0 yielded Ghanaian Streptomyces bacterial solution;

[0066] S3: Mix the two bacterial solutions obtained at a volume ratio of 1:1, freeze-dry them into freeze-dried powder, and obtain a compound microbial agent.

[0067] The preparation method of the tea seed cake-biochar composite carrier is as follows:

[0068] (1) Biochar preparation: The tea seed shells are dried to a moisture content of less than 15%, crushed into particles of 0.5-2cm, and the raw materials are placed in a muffle furnace. The temperature is raised to 500℃ under a nitrogen atmosphere and maintained for 1h. After carbonization, the temperature is cooled to room temperature and crushed into particles with a particle size of 0.5-1mm.

[0069] (2) Pretreatment of tea seed cake: Mix tea seed cake powder, water and EM bacterial solution evenly, pile them up and ferment for 15 days;

[0070] (3) Construction of composite carrier: Biochar and pretreated tea seed dry matter were mixed evenly at a mass ratio of 3:1. The mixed material was piled up for 48 hours and dried in a ventilated environment at 40°C to reduce the moisture content to 10% to obtain tea seed-biochar composite carrier.

[0071] In step (2), the mass ratio of tea seed cake powder to water is 1:0.8, and the amount of EM bacterial solution added is 1.5% of the mass of tea seed cake powder.

[0072] The soil conditioner comprises calcined potassium feldspar powder and diatomaceous earth in a mass ratio of 1:2.

[0073] A method for preparing a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases includes the following steps:

[0074] First, prepare a compound microbial inoculant and a tea seed cake-biochar composite carrier. Then, mix earthworm castings, straw powder, seaweed residue, tea seed cake-biochar composite carrier, compound microbial inoculant, bitter melon extract, short-stem mold polysaccharide, and soil conditioner evenly using a mechanical mixer to obtain the final product, bio-organic fertilizer.

[0075] Comparative Example 1

[0076] Compared with Example 3, this comparative example is identical to Example 3 except that the volume ratio of Bacillus hygroscopicus and Streptomyces garneriensis in the compound microbial inoculum is changed to 2:1.

[0077] Comparative Example 2

[0078] Compared with Example 3, this comparative example uses the same raw materials and steps as Example 3, except for the compound microbial bacterial solution of Bacillus hygroscopicus.

[0079] Comparative Example 3

[0080] Compared with Example 3, this comparative example uses the same raw materials and steps as Example 3, except that the compound microbial solution only uses Streptomyces garneriensis.

[0081] Comparative Example 4

[0082] Compared with Example 3, this comparative example is identical to Example 3 except that bitter melon extract is not added. All other raw materials and steps are the same as in Example 3.

[0083] Performance testing

[0084] Inhibitory effect of compound microbial inoculants on pathogens causing several potato diseases

[0085] Plate confrontation method: The two microbial cultures from Example 3 were inoculated onto LB medium and incubated at 30°C for two days for activation. The strains of *Potamogeton pluvialis*, *Fusarium wilt*, and *Scab* were inoculated onto PDA medium and incubated at 28°C for 5 days for activation. Then, using an 8mm punch, holes were punched in the activated strains and pathogens. The bacterial discs were inoculated in pairs onto PDA medium, with plates inoculated only with pathogens serving as controls. Each treatment was repeated three times. After incubation at 28°C for 5 days, the width of the inhibition band was measured and calculated. Inhibition rate (%) = (Control colony diameter - Treated colony diameter) / Control colony diameter × 100%. The detection data are shown in Table 1.

[0086] Table 1. Inhibitory effects of two strains on various pathogens.

[0087]

[0088] As shown in Table 1, both strains selected in this invention have antagonistic effects against various potato diseases. Bacillus hygroscopicus has the best inhibitory effect on Fusarium wilt pathogens, while Streptomyces garnaana has the best inhibitory effect on scab pathogens.

[0089] Field trials

[0090] Soil physicochemical properties in the experimental area (0-20cm): organic matter content 9.65g / kg, available nitrogen content 61.12 mg / kg, available phosphorus content 36.47mg / kg, available potassium content 133.24 mg / kg, bulk density 1.46 g / cm³ 3 Porosity 45.38%.

[0091] The experiment included the application of bio-organic fertilizers prepared in Examples 1-3 and Comparative Examples 1-4, as well as a blank control. Each treatment group was planted with 20 potato seedlings, with three replicates. The potato variety was Qingshu No. 9, with a seedling spacing of 30 cm and a row spacing of 60 cm. Each plot was arranged in a randomized block design. A concentration of 1×10⁻⁶ was used. 8 A single pathogen sample (CFU / mL) was taken in 50ml and applied separately to the roots of each plant. Then, bio-organic fertilizer from each treatment group was applied to the roots of the plants at a rate of 100kg / mu. The inhibitory effect of the bio-organic fertilizer on various diseases was tested. The experimental field was managed according to standard field practices. All tubers were harvested from all plants to investigate disease incidence, calculate the disease index, and determine the control effect.

[0092] Grading criteria for potato black scab disease:

[0093] Grade 0: No sclerotia are present on the surface of the tuber;

[0094] Grade 1: The area of ​​sclerotia on the tuber surface accounts for less than 1% of the total tuber area;

[0095] Level 2: 1% < the area of ​​sclerotia on the tuber surface accounts for ≤10% of the total tuber area;

[0096] Level 3: 10% < the area of ​​sclerotia on the tuber surface accounts for ≤20% of the total tuber area;

[0097] Level 4: 20% < the area of ​​sclerotia on the tuber surface accounts for ≤50% of the total tuber area;

[0098] Level 5: The sclerotia area on the tuber surface accounts for more than 50% of the total tuber area.

[0099] Disease index = Σ(Disease grade × Number of plants at that disease grade) / (Highest disease grade × Total number of plants) × 100%

[0100] Prevention efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%.

[0101] Potato scab disease severity grading criteria:

[0102] Grade 0: No disease spots on the surface of the tuber;

[0103] Grade 1: 1% < the area of ​​scabs and lesions accounts for ≤5% of the total tuber area;

[0104] Grade 2: 5% < the area of ​​scabs and lesions accounts for ≤25% of the total tuber area;

[0105] Grade 3: 25% < the area of ​​scabs and lesions accounts for ≤50% of the total tuber area;

[0106] Grade 4: 50% < the area of ​​scabs and lesions accounts for ≤75% of the total tuber area;

[0107] Level 5: The area of ​​scabs and lesions accounts for more than 75% of the total tuber area.

[0108] Disease index = Σ(Disease grade × Number of plants at that disease grade) / (Highest disease grade × Total number of plants) × 100%

[0109] Prevention efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%.

[0110] Potato Fusarium wilt disease severity grading standards:

[0111] Grade 0: Leaves show no obvious yellowing or wilting, and the plant is growing normally;

[0112] Grade 1: 0 < leaves withered and yellowed ≤ 25%;

[0113] Grade 2: 25% < leaf yellowing and wilting ≤ 50%;

[0114] Grade 3: 50% < leaves yellowing and wilting ≤ 75%;

[0115] Level 4: More than 75% of the leaves are wilted or the entire plant is dead.

[0116] Disease index = Σ(Disease grade × Number of plants at that disease grade) / (Highest disease grade × Total number of plants) × 100%

[0117] Prevention efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%.

[0118] Table 2. Control effects of bio-organic fertilizer on various pathogens in each treatment group.

[0119]

[0120] The data in the table show that the bio-organic fertilizer of this invention can effectively prevent and control potato black scurf, scab, and wilt, with a control effect of over 60% against all three pathogens, especially the best effect against wilt. Furthermore, changing the strain ratio by 2-3 disrupted the synergistic balance between the two strains, significantly reducing their resistance to potato diseases.

[0121] Soil sample collection and analysis:

[0122] During the potato harvesting period, soil samples from the 0-20cm soil layer were collected from each treatment group's experimental area using a 5-point sampling method. Soil organic matter, available nitrogen, available phosphorus, and available potassium were measured. Organic matter content was determined using the externally heated potassium dichromate oxidation method; available nitrogen was determined using the alkaline diffusion method; available phosphorus content was determined by colorimetry after extraction with 0.5 mol / L NaHCO3; available potassium content was determined by flame photometry after extraction with 1 mol / L NH4OAc solution; and soil porosity and bulk density were determined using the ring sampler method. The results are shown in Table 3.

[0123] Table 3 Soil physicochemical properties

[0124]

[0125] As shown in Table 3, the physicochemical properties of the soil were improved after using the bio-organic fertilizer of this invention. Organic matter, available nitrogen, available phosphorus, available potassium, and porosity all increased to varying degrees, while soil bulk density decreased. Good soil structure and high soil fertility are key to high potato yields. Compared to the original soil, the application of the bio-organic fertilizer of this invention significantly improved soil properties and increased soil fertility. Furthermore, the bio-organic fertilizers in Examples 1-3 all reduced soil bulk density and increased soil porosity. This is because the bio-organic fertilizer, after being applied to the soil, can aggregate smaller particles into larger aggregates, improving soil permeability and exchange, thereby increasing soil porosity and reducing soil bulk density. In contrast, the comparative examples 1-4, which changed the composition of the bio-organic fertilizer, all showed varying degrees of decreased effectiveness in improving soil properties.

[0126] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases, characterized in that, The raw materials include the following parts by weight: 30-40 parts earthworm castings, 20-25 parts straw powder, 20-25 parts seaweed residue, 15-20 parts tea seed cake-biochar composite carrier, 4-6 parts compound microbial inoculant, 3-5 parts bitter melon extract, 2-3 parts short-stem mold polysaccharide, and 5-8 parts soil conditioner. The preparation method of the composite microbial agent is as follows: S1: After activating Bacillus cereus, single colonies were picked and cultured in nutrient broth at 30°C for 48 hours. The culture was then inoculated into a fermenter at 10% of the amount in the seed culture medium and cultured until the bacterial concentration reached OD500. 600 =3.0 yielded Bacillus hygroscopicus bacterial culture; S2: After activating *Streptomyces garneri*, add 0.5 ml of the bacterial suspension to ISP-2 agar medium and incubate at 28°C for 5 days. Scrape off pea-sized mycelia and spores and inoculate them into ISP-2 liquid medium, shaking for 24-48 hours to obtain the seed culture. Inoculate 10% of the seed culture into a fermenter and incubate until the bacterial concentration reaches OD500. 600 =3.0 yielded Ghanaian Streptomyces bacterial solution; S3: Mix the two bacterial solutions obtained at a volume ratio of 1:1 evenly, freeze-dry them into freeze-dried powder, and obtain a compound microbial agent; The strain number of the *Bacillus hygroscopicus* is CGMCC 1.12171, and the strain number of the *Streptomyces ghana* is CGMCC 4.1967. The preparation method of the tea seed cake-biochar composite carrier is as follows: (1) Biochar preparation: Dry the tea seed shells until the moisture content is less than 15%, crush them into particles of 0.5-2cm, put the raw materials into a muffle furnace, raise the temperature to 400-500℃ under a nitrogen atmosphere, maintain for 1-2h, cool to room temperature after carbonization, and crush into particles with a particle size of 0.5-1mm. (2) Pretreatment of tea seed cake: Mix tea seed cake powder, water and EM bacterial solution evenly, pile them up and ferment for 15 days; (3) Construction of composite carrier: Biochar and pretreated tea seed dry matter are mixed evenly at a mass ratio of 3:

1. The mixed material is piled up for 24-48 hours and dried in a ventilated environment at 40℃ to reduce the moisture content to 10% to obtain tea seed dry matter-biochar composite carrier.

2. The bio-organic fertilizer according to claim 1, which combines soil improvement and antagonism against soil-borne diseases, is characterized in that, In step (2), the mass ratio of tea seed cake powder to water is 1:0.8, and the amount of EM bacterial solution added is 1.5% of the mass of tea seed cake powder.

3. The bio-organic fertilizer according to claim 1, which combines soil improvement and antagonism against soil-borne diseases, is characterized in that... The soil conditioner comprises calcined potassium feldspar powder and diatomaceous earth in a mass ratio of 1:

2.

4. A method for preparing a bio-organic fertilizer that combines soil improvement and antagonism against soil-borne diseases as described in any one of claims 1-3, characterized in that, Includes the following steps: First, prepare a compound microbial inoculant and a tea seed cake-biochar composite carrier. Then, mix earthworm castings, straw powder, seaweed residue, tea seed cake-biochar composite carrier, compound microbial inoculant, bitter melon extract, short-stem mold polysaccharide, and soil conditioner evenly using a mechanical mixer to obtain the final product, bio-organic fertilizer.

5. The application of a bio-organic fertilizer as described in any one of claims 1-3, which combines soil improvement and antagonism against soil-borne diseases, characterized in that... The bio-organic fertilizer is used for soil improvement and effectively prevents and controls potato black scurf, potato scab, and potato wilt.

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