A solid bio-fertilizer for rutaceae

Abstract

The application provides a solid-state bio-bacterial fertilizer for Rutaceae, and the solid-state bio-bacterial fertilizer is prepared by inducing probiotic expression of Rutaceae plants, cultivating and screening specific flora, and developing a bacteria-charcoal-plant triple interaction carrier based on pomace resource utilization. The pomace-rice husk mixture is prepared into a charcoal carrier through pressing pyrolysis, and flavanol activates the flora response. The compound bacterial liquid is wrapped by pectin-active white clay gel to form a soil-responsive slow-release structure, so that the solid-state bio-bacterial fertilizer with improved Rutaceae soil, agricultural product yield and fruit quality is obtained.

Description

Technical Field

[0001] This invention belongs to the technical field of bio-fertilizers, specifically relating to a solid bio-fertilizer for Rutaceae plants. Background Technology

[0002] While traditional fast-dissolving fertilizers can increase yields, their nutrient release per unit time far exceeds the crop's absorption capacity. Combined with losses through leaching, volatilization, and fixation, this results in low fertilizer utilization, leading to resource waste and environmental pollution. Therefore, developing slow-release bio-fertilizers that combine microbial functions and slow-release nutrient characteristics is an important direction for improving nutrient utilization efficiency and reducing resource waste.

[0003] Bio-fertilizers (microbial fertilizers) are functional fertilizers containing specific living microorganisms. Through the life activities of these microorganisms, they improve the soil ecological environment and enhance plant nutrition. Their core value lies primarily in maintaining soil health, promoting plant growth, and supporting sustainable agricultural development. Microorganisms activate soil nutrients and improve fertilizer utilization through nitrogen fixation, phosphorus solubilization, and potassium release; they decompose organic matter to form humus, enhancing soil aggregate structure and water and fertilizer retention capacity; simultaneously, they competitively inhibit the reproduction of pathogens, building a healthy soil micro-ecology. For plants, the growth hormones secreted by microorganisms stimulate root development, enhance stress resistance, and reduce the incidence of pests and diseases by inducing systemic resistance. From an agricultural sustainability perspective, bio-fertilizers can reduce the use of chemical fertilizers and pesticides, alleviate non-point source pollution, and promote the transformation to green agriculture.

[0004] Rutaceae crops (such as trifoliate orange, citrus, lemon, and pomelo) are important economic fruit trees, but they have long faced problems such as continuous cropping obstacles, high incidence of soil-borne diseases, and soil acidification and compaction. Therefore, the targeted development of solid bio-fertilizers has irreplaceable advantages.

[0005] However, key challenges remain in the preparation of solid bio-fertilizers containing Rutaceae: First, it is necessary to screen local strains that are adapted to acidic soils and have Rutaceae-specific growth-promoting or biocontrol functions, as these strains often have better effects on the target crops; second, the fertilizer carriers selected for bio-fertilizers must have excellent water retention, air permeability, and slow nutrient release (commonly used materials include peat, vermiculite, and organic waste); and finally, the synergy between the microbial strains and the carrier is a key factor affecting fertilizer efficiency. Summary of the Invention

[0006] This invention discloses a solid bio-fertilizer for Rutaceae plants, to solve any of the above-mentioned and potential problems in the prior art. To solve the above-mentioned technical problems, this invention provides the following preparation process for the bio-fertilizer: 72 hours before sampling, inject 10 mL of activation solution into the root zone of Rutaceae Citrus plants at a depth of 5-10 cm, within 10 cm of the main root; The activation solution is composed of chitosan oligosaccharide with a mass fraction of 0.15-0.20% and naringenin with a mass fraction of 0.012-0.018% in equal proportions.

[0007] Sample collection: Root soil samples were collected from the root zone of 3-5 year old citrus trees (Citrus genus, Rutaceae family) at a distance of 0-4 mm from the root. Impurities were removed by sieving through a 2 mm sieve. Ten root samples were then immersed in 200 parts of 0.9-1.5% sterile phosphate buffer for 6 hours. The mixture was then shaken at 180 rpm for 1 minute and centrifuged at 8000 rpm for 10 minutes to collect the surface deposits. The samples were stored at 4℃. The roots were then surface-sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 20-40% sterile water to obtain a homogenized root tissue. Among them, plants in the Rutaceae family and Citrus genus mainly include trifoliate orange, mandarin orange, orange, pomelo, lemon and other citrus fruits.

[0008] Selective enrichment culture includes: 1) Enrichment of nitrogen-fixing bacteria: Take 2-5 samples of the original solution and inoculate them into 100 portions of nitrogen-free Assumption liquid medium. Adjust the pH to 6.8±0.1 and culture at 30℃ and 180rpm for 7 days. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 2-5 samples of original solution and inoculate them into 100 samples of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% extract of citrus foliage from Rutaceae plants. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. Among them, the extract of decaying leaves of Rutaceae Citrus plants was obtained by sterilizing at 121℃ for 20 minutes and then filtering the solution with a ratio of decaying leaves to water of 1:10. 3) PGPR enrichment: Take 2-5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48 hours; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0009] The enriched bacterial groups were cultured to a scale-up of OD600 ≥ 1.2 for nitrogen-fixing bacteria, OD600 ≥ 1.5 for phosphate-solubilizing bacteria, OD600 ≥ 2.0 for PGPR, and OD600 ≥ 1.1 for biocontrol bacteria. They were then mixed stepwise at 30-40℃ in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step. After stirring for 30 minutes, a composite bacterial solution with a viable count OD600 ≥ 5.0 was obtained.

[0010] Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. The original solution was selectively enriched and cultured to obtain a compound bacterial solution.

[0011] Fruit pomace pretreatment: Waste citrus fruits of the Rutaceae family are mechanically pressed to obtain fruit pomace; the fruit pomace is mixed with rice husks at a weight ratio of 5:1-2, spread out to dry, with a thickness of ≤10cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 30-35%. Biochar preparation: Take the above-mentioned dried mixed fruit pomace-rice husk material and perform oxygen-limited pyrolysis, calcine at 400℃ for 45 minutes to produce biochar, cool and then crush to a particle size of 2-5 mm; Microbial-charcoal composite: Mix the compound microbial liquid with the pressed fruit pomace at a mass ratio of 1:1 to obtain a compound liquid, then mix it with biochar at a mass ratio of 1:1.5, and add 0.2-0.5% of the total mass of inducing agent. After stirring evenly, let it stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The inducing agent is flavanol.

[0012] The above raw materials are fermented and solidified to prepare bio-fertilizer.

[0013] The fermentation and solidification process involves preparing 20-30 parts of a microbial-charcoal composite, 60-70 parts of a mixture of fruit pomace and rice husks, 8-12 parts of peat, and 10-20 parts of activated clay. Water is added to adjust the moisture content to 50-55%, and the mixture is piled up to a height of 1.2m. Fermentation is carried out for 4 days at a temperature of 60±2℃, with the pile turned over every 2 days. From day 5 to 15, the temperature is maintained at 55±2℃, and the pile is turned over every 5 days. From day 16 to 20, the temperature is lowered to <40℃, and the pile is turned over once before stopping. The pile is then loosened and maintained at 35-40℃ and 40% humidity for 7 days of post-ripening. The mixture is then air-dried until the moisture content is ≤30%, and coarsely crushed into particles with a diameter of 3-5mm to obtain the bio-fertilizer.

[0014] An application of solid bio-fertilizer for Rutaceae plants during transplanting is described. The specific application method is as follows: bury the solid bio-fertilizer at a depth of 8cm from the soil, using 50g per plant. The burying location should be no more than 1.5cm away from the root system. Simultaneously, mix the solid bio-fertilizer with the soil at a ratio of 1:3 and backfill the soil, with a backfill thickness of no more than 2cm. Apply topdressing 7-10 days after transplanting. Specifically, mix 60g of solid bio-fertilizer with a mixture of chitosan oligosaccharide and naringenin in an equal ratio of 100:1, then dilute with 3 times the amount of water before applying the topdressing.

[0015] A method for applying a solid bio-fertilizer for Rutaceae plants during planting is as follows: For mature Rutaceae plants, during the flowering period, mix 1.0 kg of solid bio-fertilizer with an equal ratio of chitosan oligosaccharide and naringenin at a ratio of 200:1, then dilute with 5 times the amount of water for topdressing; during the fruit enlargement period, mix 1.0 kg of solid bio-fertilizer with an equal ratio of chitosan oligosaccharide and naringenin at a ratio of 200:1, then dilute with 5 times the amount of water for topdressing.

[0016] The advantages and beneficial effects of this invention are as follows: 1. The process of this invention specifically stimulates the root exudates of Citrus species, directionally enriches the rhizosphere beneficial bacteria, and utilizes Citrus fruit residue resources to construct a "bacterial-charcoal complex" carrier to achieve efficient colonization and slow-release protection of functional strains; combined with a staged temperature-controlled fermentation process, it produces a Rutaceae-specific bio-fertilizer with soil remediation, nutrient activation and biocontrol functions.

[0017] 2. Activation of Rutaceae root systems involves screening local functional microbial communities adapted to acidic soils from multiple dimensions, including the rhizosphere, root surface, and root interior. This significantly enhances the environmental adaptability and host affinity of the strains, improves the soil environment, promotes rapid root growth, and cultivates a favorable rhizosphere environment. Using fruit pomace-derived biochar as the core carrier, a microbial-charcoal symbiotic structure is formed through flavanol induction, strengthening the survival rate and functional sustainability of the microbial community while simultaneously achieving the resource recycling of agricultural waste. The fermentation process integrates the slow-release nutrients of fruit pomace-rice husk mixture, the water retention and aeration properties of peat, and the ion exchange capacity of activated clay, forming a ternary synergistic system of active microbial communities, organic matrix, and mineral carrier. This activated clay is waste clay from oil decolorization, containing relatively high levels of fats, proteins, carbon sources, and nitrogen sources, which can accelerate fermentation, reduce costs, and simultaneously improve soil physicochemical properties, inhibit soil-borne diseases, and promote fruit quality improvement.

[0018] 3. Chitosan oligosaccharides that activate the root system of Rutaceae plants can activate the plant's defense pathways and induce the secretion of antibacterial phenolic acids. Simultaneously, naringenin specifically recruits Rutaceae native probiotics that can metabolize this substance, and combines with the flavonoid-sensing protein of the bacterial community to activate symbiotic genes, forming a "stress simulation-functional bacteria enrichment" mechanism. The bacterial communities screened in this process possess inherent host niche adaptation characteristics. Further enrichment of the bacterial communities involves using citrus leaf extract to screen for highly efficient phosphate-solubilizing bacteria. Additionally, adding inactivated Penicillium mycelium during the biocontrol bacteria enrichment process can simulate citrus pathogen stress and selectively target biocontrol bacteria resistant to Penicillium and Alternaria.

[0019] 4. In the fertilizer carrier, based on the resource utilization of Rutaceae fruit pomace, a three-dimensional interaction system of bacteria-charcoal-plant is constructed. The mixture of fruit pomace and rice husk is pressed to form a carbon source carrier, and part of it is pyrolyzed into biochar under limited oxygen. The pores of this biochar form a microenvironment that resists free radicals and prolongs the activity of the bacterial community. After the compound bacterial liquid is combined with the fruit pomace juice, the pores of the biochar are activated by flavanols. Then, through gradient fermentation and solidification technology, the pectin components in the fruit pomace and the activated clay form a gel to encapsulate the bacterial community, thereby forming a slow-release structure. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the embodiments. The following Rutaceae citrus plants mainly include dried trifoliate orange, mandarin orange, orange, pomelo, etc. In the following embodiments, dried trifoliate orange is selected as the Rutaceae citrus plant for implementation. The compound fertilizer used in the following embodiments is NPK:12-0-3, purchased from Huanong Yuanlin Co., Ltd., and the microbial fertilizer with effective live bacteria ≥200 million / g is purchased from Henan Qiangsheng Agricultural Technology Development Co., Ltd. The activated bleaching clay is waste bleaching clay from oil decolorization, purchased from Guangzhou Zhanfei Chemical Technology Co., Ltd. The Rutaceae citrus fruits used below include dried trifoliate orange, orange, pomelo, mandarin orange, etc. Example 1

[0021] 72 hours before sampling, 10 mL of activation solution was injected into the root zone of Citrus plants of the Rutaceae family. The activation solution was a mixture of chitosan oligosaccharide (0.18% by mass) and naringenin (0.015% by mass) in equal proportions. The injection depth was 8 cm, within 10 cm of the main root. Sample collection: Root soil samples were collected from the root zone of 5-year-old new-growth trifoliate orange trees, 2 mm from the root. The soil was sieved through a 2 mm sieve to remove impurities. Ten root samples were then immersed in 200 parts of 1.2% sterile phosphate buffer for 6 hours. After shaking at 180 rpm for 1 minute, the samples were centrifuged at 8000 rpm for 10 minutes to collect the precipitate on the root surface. The samples were stored at 4℃. The roots were then surface sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 30% sterile water to obtain a homogenized root tissue. Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. Selective enrichment culture: 1) Enrichment of nitrogen-fixing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of nitrogen-free Assumption liquid medium. Adjust the pH to 6.8 and culture at 30℃ and 180 rpm for 7 days. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% fresh dried trifoliate orange leaf extract. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. The extract of dried bitter orange peel and decaying leaves was obtained by sterilizing at 121℃ for 20 minutes and then filtering, with a leaf decay:water ratio of 1:10. 3) PGPR enrichment: Take 3.5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48h; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0022] The enriched bacterial groups were cultured separately until the OD600 of nitrogen-fixing bacteria was 1.3, that of phosphate-solubilizing bacteria was 1.5, that of PGPR was 2.0, and that of biocontrol bacteria was 1.2. They were then mixed stepwise at 18°C ​​in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step and stirring for 30 minutes to obtain a composite bacterial solution with a viable count OD600 of 5.8.

[0023] Fruit pomace pretreatment: The discarded freshly dried trifoliate orange fruits are mechanically pressed to obtain fruit pomace; the fruit pomace and rice husks are mixed at a weight ratio of 5:1.5, spread out to dry in the sun to a thickness of 10cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 32%. Biochar preparation: The above-mentioned dried mixed fruit pomace-rice husk material was subjected to oxygen-limited pyrolysis and calcined at 400℃ for 45 min to produce biochar. After cooling, it was crushed to a particle size of 4 mm. Microbial-charcoal composite: The compound microbial liquid and the pressed fruit pomace are mixed evenly at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with biochar at a mass ratio of 1:1.5, and 0.35% flavanols are added. After stirring evenly, the mixture is allowed to stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The above raw materials are fermented and solidified: 25 parts of microbial-charcoal composite, 65 parts of fruit pomace-rice husk mixture, 10 parts of peat, and 15 parts of activated clay are mixed together. Water is added to adjust the moisture content to 52%, and the pile is piled up to a height of 1.2m. It is left to ferment for 4 days at a temperature of 60℃, and the pile is turned over once every 2 days. On the 10th day, the temperature is maintained at 55℃, and the pile is turned over once every 5 days. On the 18th day, the temperature is lowered to 38℃, the pile is turned over once, and then the pile is loosened. The temperature is maintained at 38℃ and the humidity at 40%. After 7 days of post-ripening, the pile is air-dried until the moisture content is 28%, and then coarsely crushed into particles with a particle size of 4mm to obtain bio-fertilizer. Example 2

[0024] 72 hours before sampling, 10 mL of activation solution was injected into the root zone of Citrus plants of the Rutaceae family. The activation solution was a mixture of 0.15% chitosan oligosaccharide and 0.018% naringenin in equal proportions. The injection depth was 5 cm, within 10 cm of the main root. Sample collection: Root soil samples were collected from the root zone of 5-year-old new-growth trifoliate orange trees, 4 mm from the root. The soil was sieved through a 2 mm sieve to remove impurities. Ten root samples were then immersed in 200 parts of 0.9% sterile phosphate buffer for 6 hours. After shaking at 180 rpm for 1 minute, the samples were centrifuged at 8000 rpm for 10 minutes to collect the precipitate on the root surface. The samples were stored at 4℃. The roots were then surface sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 40% sterile water to obtain a homogenized root tissue. Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. Selective enrichment culture: 1) Enrichment of nitrogen-fixing bacteria: Take 2 samples of original solution and inoculate them into 100 portions of nitrogen-free Assumption liquid medium. Adjust the pH to 6.9 and culture at 30℃ and 180 rpm for 7 days with shaking. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 5 original sample solutions and inoculate them into 100 portions of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% fresh dried trifoliate orange peel leaf extract. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. The extract of freshly dried bitter orange peel is obtained by sterilizing the decomposed leaves and water in a ratio of 1:10 at 121°C for 20 minutes and then filtering. 3) PGPR enrichment: Take 2-5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48h; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0025] The enriched bacterial groups were cultured to a scale-up of 1.2 for nitrogen-fixing bacteria, 1.5 for phosphate-solubilizing bacteria, 2.0 for PGPR, and 1.1 for biocontrol bacteria. They were then mixed stepwise at 20°C in a volume ratio of 35:25:20:20, following the order of nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step. After stirring for 30 minutes, a composite bacterial solution with a viable count OD600 of 5.6 was obtained.

[0026] Fruit pomace pretreatment: Waste oranges are mechanically pressed to obtain fruit pomace; the fruit pomace and rice husks are mixed at a weight ratio of 5:1, spread out to dry in the sun to a thickness of 8cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 35%. Biochar preparation: The above-mentioned dried mixed fruit pomace-rice husk material was subjected to oxygen-limited pyrolysis and calcined at 400℃ for 45 min to produce biochar. After cooling, it was crushed to a particle size of 2 mm. Microbial-charcoal composite: The compound microbial liquid and the pressed fruit pomace are mixed evenly at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with biochar at a mass ratio of 1:1.5, and 0.5% flavanols are added. After stirring evenly, the mixture is allowed to stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The above raw materials are fermented and solidified: Prepare 20 parts of microbial-charcoal composite, 70 parts of fruit pomace-rice husk mixture, 8 parts of peat, and 20 parts of activated clay. Add water to adjust the moisture content to 55%, pile it up to a height of 1.2m, and let it ferment for 4 days at a temperature of 62℃, turning it over once every 2 days. From day 5 to 15, maintain the temperature at 57℃, turning it over once every 5 days. From day 16 to 20, lower the temperature to 39℃, turn it over once, and then stop. Loosen the pile, maintain the temperature at 35℃ and humidity at 40%, and allow it to mature for 7 days. Then, air-dry it until the moisture content is 26%, and coarsely crush it into particles with a particle size of 5mm to obtain bio-fertilizer. Example 3

[0027] 72 hours before sampling, 10 mL of activation solution was injected into the root zone of the Rutaceae Citrus plant. The activation solution was a mixture of 0.20% chitosan oligosaccharide and 0.012% naringenin in equal proportions. The injection depth was 10 cm, within 10 cm of the main root. Sample collection: Root soil samples were collected from the root zone of newly harvested 3-year-old trifoliate orange trees, 1 mm from the root. The soil was sieved through a 2 mm sieve to remove impurities. Ten root samples were then immersed in 200 parts of 1.5% sterile phosphate buffer for 6 hours. After shaking at 180 rpm for 1 minute and centrifuging at 8000 rpm for 10 minutes, the surface deposits were collected and stored at 4℃. The roots were then surface sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 20% sterile water to obtain a homogenized root tissue. Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. Selective enrichment culture: 1) Enrichment of nitrogen-fixing bacteria: Take 5 original sample solutions and inoculate them into 100 portions of nitrogen-free Assumption liquid medium. Adjust the pH to 6.7 and culture at 30℃ and 180 rpm for 7 days. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 2 original sample solutions and inoculate them into 100 portions of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% fresh dried trifoliate orange peel leaf extract. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. The extract of dried bitter orange peel and decaying leaves was obtained by sterilizing at 121℃ for 20 minutes and then filtering, with a leaf decay:water ratio of 1:10. 3) PGPR enrichment: Take 2-5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48h; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0028] The enriched bacterial groups were cultured separately until the OD600 of nitrogen-fixing bacteria was 1.2, that of phosphate-solubilizing bacteria was 1.6, that of PGPR was 2.1, and that of biocontrol bacteria was 1.2. They were then mixed stepwise at 15°C in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step and stirring for 30 minutes to obtain a composite bacterial solution with a viable count OD600 of 5.5.

[0029] Fruit pomace pretreatment: Waste orange fruits are mechanically pressed to obtain fruit pomace; the fruit pomace and rice husks are mixed at a weight ratio of 5:1-2, spread out to dry in the sun to a thickness of 7cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 30%. Biochar preparation: The above-mentioned dried mixed fruit pomace-rice husk material was subjected to oxygen-limited pyrolysis and calcined at 400℃ for 45 min to produce biochar. After cooling, it was crushed to a particle size of 5 mm. Microbial-charcoal composite: The compound microbial liquid and the pressed fruit pomace are mixed evenly at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with biochar at a mass ratio of 1:1.5, and 0.2% flavanols are added. After stirring evenly, the mixture is allowed to stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The above raw materials are fermented and solidified: Prepare 30 parts of microbial-charcoal composite, 60 parts of fruit pomace-rice husk mixture, 12 parts of peat, and 10 parts of activated clay. Add water to adjust the moisture content to 50%, pile it up to a height of 1.2m, and let it ferment for 4 days at a temperature of 58℃, turning it over once every 2 days. From day 5 to 15, maintain the temperature at 55±2℃, turning it over once every 5 days. From day 16 to 20, lower the temperature to 36℃, turn it over once, and then stop. Loosen the pile, maintain the temperature at 40℃ and humidity at 40%, and allow it to mature for 7 days. Then, air-dry it until the moisture content is 27%, and coarsely crush it into particles with a particle size of 3mm to obtain bio-fertilizer.

[0030] Comparative Example 1 The difference between this comparative example and Example 1 is that the specific process in this comparative example is as follows: Sample collection: Root soil samples were collected from the root zone of 4-year-old new-growth trifoliate orange trees, 2 mm from the root. The soil was sieved through a 2 mm sieve to remove impurities. Ten root samples were then immersed in 200 parts of 1.2% sterile phosphate buffer for 6 hours. After shaking at 180 rpm for 1 minute and centrifuging at 8000 rpm for 10 minutes, the surface deposits were collected and stored at 4℃. The roots were then surface sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 30% sterile water to obtain a homogenized root tissue. Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. Selective enrichment culture: 1) Enrichment of nitrogen-fixing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of nitrogen-free Assumption liquid medium. Adjust the pH to 6.8 and culture at 30℃ and 180 rpm for 7 days. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation. Repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% fresh dried trifoliate orange leaf extract. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. The extract of dried bitter orange peel and decaying leaves was obtained by sterilizing at 121℃ for 20 minutes and then filtering, with a leaf decay:water ratio of 1:10. 3) PGPR enrichment: Take 3.5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48h; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0031] The enriched bacterial groups were cultured separately until the OD600 of nitrogen-fixing bacteria was 1.3, that of phosphate-solubilizing bacteria was 1.5, that of PGPR was 2.0, and that of biocontrol bacteria was 1.2. They were then mixed stepwise at 18°C ​​in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step and stirring for 30 minutes to obtain a composite bacterial solution with a viable count OD600 of 5.8.

[0032] Fruit pomace pretreatment: The discarded freshly dried trifoliate orange fruits are mechanically pressed to obtain fruit pomace; the fruit pomace and rice husks are mixed at a weight ratio of 5:1.5, spread out to dry in the sun to a thickness of 10cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 32%. Biochar preparation: The above-mentioned dried mixed fruit pomace-rice husk material was subjected to oxygen-limited pyrolysis and calcined at 400℃ for 45 min to produce biochar. After cooling, it was crushed to a particle size of 4 mm. Microbial-charcoal composite: The compound microbial liquid and the pressed fruit pomace are mixed evenly at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with biochar at a mass ratio of 1:1.5, and 0.35% flavanols are added. After stirring evenly, the mixture is allowed to stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The above raw materials are fermented and solidified: 25 parts of microbial-charcoal composite, 65 parts of fruit pomace-rice husk mixture, 10 parts of peat, and 15 parts of activated clay are mixed together. Water is added to adjust the moisture content to 52%, and the pile is piled up to a height of 1.2m. It is left to ferment for 4 days at a temperature of 60℃, and the pile is turned over once every 2 days. On the 10th day, the temperature is maintained at 55℃, and the pile is turned over once every 5 days. On the 18th day, the temperature is lowered to 38℃, the pile is turned over once, and then the pile is loosened. The temperature is maintained at 38℃ and the humidity at 40%. After 7 days of post-ripening, the pile is air-dried until the moisture content is 28%, and then coarsely crushed into particles with a particle size of 4mm to obtain bio-fertilizer.

[0033] Comparative Example 2 The difference between this comparative example and Example 1 is that in this comparative example, 72 hours before sampling, 10 mL of activation solution (0.18% by mass) was injected into the root zone of the Rutaceae Citrus plant. The injection depth was 8 cm, within 10 cm of the main root; the rest was the same as in Example 1.

[0034] Comparative Example 3 The difference between this comparative example and Example 1 is that in this comparative example, 72 hours before sampling, 10 mL of activation solution (0.015% naringenin by mass) was injected into the root zone of the Rutaceae Citrus plant. The injection depth was 8 cm, within 10 cm of the main root; the rest was the same as in Example 1.

[0035] Comparative Example 4 The difference between this comparative example and Example 1 is that in this comparative example, 72 hours before sampling, 10 mL of activation solution (0.015% methyl salicylate) was injected into the root zone of the Rutaceae Citrus plant. The injection depth was 8 cm, within 10 cm of the main root; the rest was the same as in Example 1.

[0036] Comparative Example 5 The difference between this comparative example and Example 1 is that the specific process in this comparative example is as follows: Sample collection: Select the root zone of a 4-year-old new-growth trifoliate orange tree, collect root soil 2mm from the root, and remove impurities by passing it through a 2mm sieve; Sample stock solution: Take root soil and add 9 times the mass of sterile physiological saline to prepare the stock solution; Selective enrichment culture: 1) Enrichment of nitrogen-fixing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of nitrogen-free Assumption liquid medium. Adjust the pH to 6.8 and culture at 30℃ and 180 rpm for 7 days. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% fresh dried trifoliate orange leaf extract. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. The extract of dried bitter orange peel and decaying leaves was obtained by sterilizing at 121℃ for 20 minutes and then filtering, with a leaf decay:water ratio of 1:10. 3) PGPR enrichment: Take 3.5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48h; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0037] The enriched bacterial groups were cultured separately until the OD600 of nitrogen-fixing bacteria was 1.3, that of phosphate-solubilizing bacteria was 1.5, that of PGPR was 2.0, and that of biocontrol bacteria was 1.2. They were then mixed stepwise at 18°C ​​in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step and stirring for 30 minutes to obtain a composite bacterial solution with a viable count OD600 of 5.8.

[0038] Fruit pomace pretreatment: The discarded freshly dried trifoliate orange fruits are mechanically pressed to obtain fruit pomace; the fruit pomace and rice husks are mixed at a weight ratio of 5:1.5, spread out to dry in the sun to a thickness of 10cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 32%. Biochar preparation: The above-mentioned dried mixed fruit pomace-rice husk material was subjected to oxygen-limited pyrolysis and calcined at 400℃ for 45 min to produce biochar. After cooling, it was crushed to a particle size of 4 mm. Microbial-charcoal composite: The compound microbial liquid and the pressed fruit pomace are mixed evenly at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with biochar at a mass ratio of 1:1.5, and 0.35% flavanols are added. After stirring evenly, the mixture is allowed to stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The above raw materials are fermented and solidified: 25 parts of microbial-charcoal composite, 65 parts of fruit pomace-rice husk mixture, 10 parts of peat, and 15 parts of activated clay are mixed together. Water is added to adjust the moisture content to 52%, and the pile is piled up to a height of 1.2m. It is left to ferment for 4 days at a temperature of 60℃, and the pile is turned over once every 2 days. On the 10th day, the temperature is maintained at 55℃, and the pile is turned over once every 5 days. On the 18th day, the temperature is lowered to 38℃, the pile is turned over once, and then the pile is loosened. The temperature is maintained at 38℃ and the humidity at 40%. After 7 days of post-ripening, the pile is air-dried until the moisture content is 28%, and then coarsely crushed into particles with a particle size of 4mm to obtain bio-fertilizer.

[0039] Comparative Example 6 The difference between this comparative example and Example 1 is that the specific process in this comparative example is as follows: 72 hours before sampling, 10 mL of activation solution was injected into the root zone of Citrus plants of the Rutaceae family. The activation solution was a mixture of chitosan oligosaccharide (0.18% by mass) and naringenin (0.015% by mass) in equal proportions. The injection depth was 8 cm, within 10 cm of the main root. Sample collection: Root soil samples were collected from the root zone of 4-year-old new-growth trifoliate orange trees, 2 mm from the root. The soil was sieved through a 2 mm sieve to remove impurities. Ten root samples were then immersed in 200 parts of 1.2% sterile phosphate buffer for 6 hours. After shaking at 180 rpm for 1 minute and centrifuging at 8000 rpm for 10 minutes, the surface deposits were collected and stored at 4℃. The roots were then surface sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 30% sterile water to obtain a homogenized root tissue. Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. Selective enrichment culture: 1) Enrichment of nitrogen-fixing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of nitrogen-free Assumption liquid medium. Adjust the pH to 6.8 and culture at 30℃ and 180 rpm for 7 days. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 3.5 samples of original solution and inoculate them into 100 samples of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% fresh dried trifoliate orange leaf extract. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. The extract of dried bitter orange peel and decaying leaves was obtained by sterilizing at 121℃ for 20 minutes and then filtering, with a leaf decay:water ratio of 1:10. 3) PGPR enrichment: Take 3.5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48h; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm.

[0040] The enriched bacterial groups were cultured separately until the OD600 of nitrogen-fixing bacteria was 1.3, that of phosphate-solubilizing bacteria was 1.5, that of PGPR was 2.0, and that of biocontrol bacteria was 1.2. They were then mixed stepwise at 18°C ​​in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step and stirring for 30 minutes to obtain a composite bacterial solution with a viable count OD600 of 5.8.

[0041] Fruit pomace pretreatment: The discarded freshly dried trifoliate orange fruits are mechanically pressed to obtain fruit pomace; the fruit pomace and rice husks are mixed at a weight ratio of 5:1.5, spread out to dry in the sun to a thickness of 10cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 32%. Microbial complex: The compound microbial liquid is mixed with the pressed fruit pomace at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with the fruit pomace-rice husk mixture at a mass ratio of 1:1.5. 0.35% flavanol is added by mass, and after stirring evenly, it is allowed to stand at 35℃ for 12 hours to obtain the microbial complex. The above raw materials are fermented and solidified: 25 parts of microbial inoculum complex, 65 parts of fruit pomace-rice husk mixture, 10 parts of peat, and 15 parts of activated clay are mixed together. Water is added to adjust the moisture content to 52%, and the pile is piled up to a height of 1.2m. It is left to ferment for 4 days at a temperature of 60℃, and the pile is turned over once every 2 days. On the 10th day, the temperature is maintained at 55℃, and the pile is turned over once every 5 days. On the 18th day, the temperature is lowered to 38℃, the pile is turned over once, and then the pile is loosened. The temperature is maintained at 38℃ and the humidity at 40%. After 7 days of post-ripening, the pile is air-dried until the moisture content is 28%, and then coarsely crushed into particles with a particle size of 4mm to obtain bio-fertilizer.

[0042] Comparative Example 7 The difference between this comparative example and Example 1 is that the specific preparation process of the microbial-char composite in this comparative example is as follows: the compound microbial liquid and the pressed fruit pomace are mixed evenly at a mass ratio of 1:1 to obtain a compound liquid, which is then mixed with biochar at a mass ratio of 1:1.5. After stirring evenly, the mixture is allowed to stand at 35°C for 12 hours to obtain the microbial-char composite; the rest is the same as in Example 1.

[0043] Comparative Example 8 The difference between this comparative example and Example 1 is that in this comparative example, flavanols are replaced with humic acid; otherwise, they are the same as in Example 1.

[0044] Experiment 1: Transplanted growth Newly grown trifoliate orange seedlings with a height of 15-20cm were selected and transplanted with soil attached. Solid bio-fertilizer was pre-buried at a depth of 8cm below the soil surface, at a rate of 50g per plant. The pre-buried location was no more than 1.5cm away from the root system. Simultaneously, the solid bio-fertilizer was mixed with soil at a ratio of 1:3 and backfilled to a thickness no greater than 2cm. Topdressing was applied 10 days after transplanting. Specifically, 60g of solid bio-fertilizer was mixed with a mixture of chitosan oligosaccharide and naringenin in a 100:1 ratio, then diluted with three times the amount of water. Twenty plants were randomly arranged in each group. A control group was prepared using commercially available microbial fertilizer administered in the same manner. The average plant height, stem diameter, number of new shoots, length of the longest new shoot, and survival rate were recorded for each group after 30 days. Survival rate = [number of surviving plants / 10] * 100. The results are shown in Table 1.

[0045] Table 1

[0046] Experiment 2: Sustained-release test The slow-release property was determined according to the agricultural industry standard NY / T 3040-2016 "Determination of Nutrient Release Rate of Slow-Release Fertilizers". Quartz sand was sieved to obtain particles with a diameter of 0.25–0.42 mm, washed, and dried at 100℃ to simulate soil pore structure. Layered packing: A 0.75 mm filter cloth was sealed at the bottom of a plastic column with an inner diameter of 5 cm and a height of 30 cm, then filled with 90 g of quartz sand. Distilled water was poured in to saturate the sand column for 24 hours. Then, 2.0 g of fertilizer sample was buried in the center, and the surface was covered with 40 g of quartz sand, ensuring uniform flow of the leachate. The temperature was 25℃±1℃. The leachate flow rate was controlled by a peristaltic pump at 13±0.5 mL / min. Distilled water was poured in to begin rinsing the sand column. The first rinse used 24 mL of distilled water, followed by 20 mL each time, rinsing once every 1 hour. The leachate was collected in a 100 mL volumetric flask, diluted to volume, and the K₂O content was determined by digestion and distillation. The sampling times for nutrient release detection were 2h, 4h, 8h, 12h, 18d, and 24d. A certain amount of supernatant was taken and diluted, and the cumulative release rate was calculated. The results are shown in Table 2 below. Table 2

[0047] Experiment 3: Effects of bio-fertilizer on Citrus aurantium and soil in Shangzhou, Xingan County A 12-mu (approximately 2.3 hectares) experimental base was selected at the *Trifolium repens* (citrus) planting base of Jiangxi Longjuzhou Agricultural Development Co., Ltd. in Hepu Township, Xingan County, Ji'an City, Jiangxi Province. Five- to ten-year-old mature *Trifolium repens* plants from Xingan Shangzhou were selected. In late March, 1.2 kg / plant of compound fertilizer (NPK: 12-0-3) and 1.2 kg / plant of organic fertilizer were applied. During the flowering period (early May), 1.0 kg of solid bio-fertilizer was mixed with an equal ratio of chitosan oligosaccharide and naringenin at a ratio of 200:1, diluted with five times the amount of water, and applied as top dressing. The fruit expanded... For topdressing during the peak period (mid-July), mix 1.0 kg of solid bio-fertilizer with an equal ratio of chitosan oligosaccharide and naringenin at a ratio of 200:1, then dilute with 5 times the amount of water for topdressing. Use commercially available microbial fertilizer mixed with compound fertilizer in the same ratio as the control group. During the harvest season of Xingan Shangzhou trifoliate orange in October and November, harvest three times according to maturity. Record the average yield per acre of the previous year per plant, and calculate the cumulative average yield per plant of Xingan Shangzhou trifoliate orange after this year's harvest.

[0048] Yield increase rate = [(This year's yield of the fertilized treatment group - last year's yield) / last year's yield] × 100% One square meter of soil was selected from each group for testing. The organic matter and total nutrients in the soil were determined according to the method in the NY525-2021 standard at the beginning and 30 days later. The results are shown in Table 3.

[0049] Table 3

Claims

1. A method for preparing solid bio-fertilizer for Rutaceae plants, characterized in that, Includes the following steps: Sample collection: Root soil samples were collected from the root zone of 3-5 year old citrus trees (Citrus genus, Rutaceae family) at a distance of 0-4 mm from the root. Impurities were removed by sieving through a 2 mm sieve. Ten root samples were then immersed in 200 parts of 0.9-1.5% sterile phosphate buffer for 6 hours. The mixture was then shaken at 180 rpm for 1 minute and centrifuged at 8000 rpm for 10 minutes to collect the surface deposits. The samples were stored at 4℃. The roots were then surface-sterilized with 75% ethanol for 30 seconds, soaked in 2.5% sodium hypochlorite for 3 minutes, rinsed three times with sterile water, and then ground with 20-40% sterile water to obtain a homogenized root tissue. Sample stock solution: The stock solution is prepared by mixing root soil, root surface attachments and root tissue in equal mass ratios and adding 9 times the mass of sterile physiological saline. The original solution was selectively enriched and cultured to obtain a compound bacterial solution; Fruit pomace pretreatment: Waste citrus fruits of the Rutaceae family are mechanically pressed to obtain fruit pomace; the fruit pomace is mixed with rice husks at a weight ratio of 5:1-2, spread out to dry, with a thickness of ≤10cm, and sun-dried for 4 hours to obtain a fruit pomace-rice husk mixture with a moisture content of 30-35%. Biochar preparation: Take the above-mentioned dried mixed fruit pomace-rice husk material and perform oxygen-limited pyrolysis, calcine at 400℃ for 45 minutes to produce biochar, cool and then crush to a particle size of 2-5 mm; Microbial-charcoal composite: Mix the compound microbial liquid with the pressed fruit pomace at a mass ratio of 1:1 to obtain a compound liquid, then mix it with biochar at a mass ratio of 1:1.5, and add 0.2-0.5% of the total mass of inducing agent. After stirring evenly, let it stand at 35℃ for 12 hours to obtain the microbial-charcoal composite. The above raw materials are fermented and solidified to prepare bio-fertilizer; The samples were collected 72 hours before sampling by injecting 10 mL of activation solution into the root zone of the Rutaceae Citrus plant at a depth of 5-10 cm, within 10 cm of the main root. The activation solution is composed of chitosan oligosaccharide at a mass fraction of 0.15-0.20% and naringenin at a mass fraction of 0.012-0.018% in equal proportions. The inducing agent is flavanol; The selective enrichment culture is as follows: 1) Enrichment of nitrogen-fixing bacteria: Take 2-5 portions of the original sample solution and inoculate it into 100 portions of nitrogen-free Assumption liquid medium, adjust the pH to 6.8±0.1, and culture at 30℃ and 180rpm for 7 days with shaking. Transfer 10% of the bacterial solution to 90 mL of fresh medium for each generation, and repeat 3 times. 2) Enrichment of phosphate-solubilizing bacteria: Take 2-5 samples of original solution and inoculate them into 100 samples of Monkina solid medium containing 0.5% tricalcium phosphate, and add 10% extract of citrus foliage from Rutaceae plants. Incubate at 28℃ for 5 days, and pick colonies with a phosphate-solubilizing zone diameter >2cm. 3) PGPR enrichment: Take 2-5 portions of the original sample solution and inoculate them into 100 portions of LB liquid medium, and incubate at 30℃ for 48 hours; 4) Biocontrol bacteria enrichment: Add 2% inactivated Penicillium mycelium to PDA medium, spread the sample and incubate at 25℃ for 72h, and select strains with inhibition zone > 5mm. The enriched bacterial groups were cultured to a scale-up of OD600 ≥ 1.2 for nitrogen-fixing bacteria, OD600 ≥ 1.5 for phosphate-solubilizing bacteria, OD600 ≥ 2.0 for PGPR, and OD600 ≥ 1.1 for biocontrol bacteria. They were then mixed stepwise at 30-40℃ in the following order: nitrogen-fixing bacteria, phosphate-solubilizing bacteria, PGPR, and biocontrol bacteria, with a 10-minute interval between each step. After stirring for 30 minutes, a composite bacterial solution with a viable count OD600 ≥ 5.0 was obtained.

2. The solid bio-fertilizer according to claim 1, characterized in that, The extract of decaying leaves from Rutaceae Citrus plants was obtained by sterilizing at 121°C for 20 minutes and then filtering, with a leaf decay to water ratio of 1:

10.

3. The solid bio-fertilizer according to claim 1, characterized in that, The fermentation and solidification process is as follows: Prepare 20-30 parts of microbial-charcoal composite, 60-70 parts of fruit pomace-rice husk mixture, 8-12 parts of peat, and 10-20 parts of activated clay. Add water to adjust the moisture content to 50-55%, pile it up to a height of 1.2m, and let it ferment for 4 days at a temperature of 60±2℃, turning it over every 2 days. From day 5 to 15, maintain the temperature at 55±2℃, turning it over every 5 days. From day 16 to 20, lower the temperature to <40℃, turn it over once, and then stop. Loosen the pile, maintain the temperature at 35-40℃ and the humidity at 40%, and allow it to mature for 7 days. Then, air-dry it until the moisture content is ≤30%, and coarsely crush it into particles with a diameter of 3-5mm to obtain the bio-fertilizer.

4. The application of a solid bio-fertilizer prepared according to claims 1-3 in transplanting, characterized in that, The specific implementation method is as follows: Pre-bury solid bio-fertilizer at a depth of 8cm from the soil, 50g per plant, with the pre-burying position no more than 1.5cm away from the root system. At the same time, mix the solid bio-fertilizer with the soil at a ratio of 1:3 and backfill it, with a backfill thickness of no more than 2cm. Top-dressing should be carried out 7-10 days after transplanting. Specifically, 60g of solid bio-fertilizer is mixed with chitosan oligosaccharide and naringenin in an equal ratio of 100:1, and then diluted with 3 times the amount of water for top-dressing.

5. The application of a solid bio-fertilizer prepared according to claims 1-3 in planting, characterized in that, The application method is as follows: For mature Rutaceae plants, during the flowering period, mix 1.0 kg of solid bio-fertilizer with an equal ratio of chitosan oligosaccharide and naringenin at a ratio of 200:1, then dilute with 5 times the amount of water for topdressing; during the fruit enlargement period, mix 1.0 kg of solid bio-fertilizer with an equal ratio of chitosan oligosaccharide and naringenin at a ratio of 200:1, then dilute with 5 times the amount of water for topdressing.

Images