An improved environment-friendly bio-organic fertilizer for acidification soil and a preparation method thereof

Abstract

The application discloses an environment-friendly biological organic fertilizer for improving acidified soil and a preparation method thereof, and belongs to the technical field of organic fertilizer. The biological organic fertilizer is prepared from the following raw materials in parts by weight: 10-20 parts of composite gel material, 80-100 parts of mature poultry manure, 10-20 parts of microbial agent, 30-50 parts of modified waste tea leaf biochar, 10-15 parts of urea, 5-10 parts of humic acid, 1-5 parts of superphosphoric acid calcium, and 1-5 parts of sodium carboxymethyl cellulose; the microbial agent is prepared by mixing bacillus firmus, pseudomonas plecoglossicida and azotobacter chroococcum at a volume ratio of 1:1:1. The biological organic fertilizer can significantly improve the soil pH, increase the content of organic matter in the soil, has good buffering capacity and long-term effect, and can enhance the water and fertilizer conservation capacity of the soil, and has a remarkable effect on increasing the yield and income of crops.

Description

Technical Field

[0001] This invention relates to the field of agricultural organic fertilizer technology, specifically to an environmentally friendly bio-organic fertilizer for improving acidified soil and its preparation method. Background Technology

[0002] Soil acidification is a natural process that accompanies the occurrence and development of soil, mainly caused by the dissociation of free carbonic acid and organic acids in the soil to produce hydrogen ions (H+). + Driven by various factors, soil acidification manifests as a continuous increase in exchangeable acidity and a continuous decrease in pH. Natural and anthropogenic factors, such as acid deposition, leaching and loss of mineral ions, and excessive application of chemical fertilizers, accelerate the soil acidification process. With the development of industrialization and intensive agriculture, soil acidification has become increasingly serious, leading to decreased soil fertility, nutrient imbalance, and accumulation of harmful substances, severely impacting crop yield and quality. Soil acidification has become one of the most serious land degradation problems in global agricultural systems, affecting as much as 30% of arable land worldwide. Soil acidification primarily affects the availability of soil nutrients. Simultaneously, it accelerates the weathering of primary and secondary aluminum-containing minerals in the soil, releasing large amounts of aluminum ions and forming aluminum-containing compounds that plants can absorb. Long-term and excessive absorption of aluminum ions by plants can cause crop poisoning or death, leading to significant yield reductions or even crop failure. Secondly, soil acidification affects the activity of soil enzymes, thus impacting crop nutrient absorption. Finally, soil acidification also leads to a significant loss of alkaline base ions such as calcium and magnesium, resulting in deterioration of soil physicochemical properties, altered soil structure, and reduced soil buffering capacity.

[0003] To effectively address soil acidification, various soil conditioners, including lime-based, organic materials, minerals, and industrial byproducts, are widely used in the remediation of acidified soils. Among these, lime-based conditioners such as quicklime, hydrated lime, and limestone offer advantages such as rapid effectiveness and good improvement results. Studies have shown that the pH of acidic soil with a pH of 4.84 increases by 32% after applying a certain amount of lime. However, long-term, excessive application of lime can lead to soil compaction, re-acidification, deficiencies in nutrients such as calcium, magnesium, phosphorus, and potassium, and a reduction in soil microbial diversity. Organic materials such as livestock and poultry manure, crop residues, and green manure are readily available and inexpensive to produce, making them more widely used in practice. However, their impact on soil pH is uncertain, and the application of manure may lead to excessive levels of heavy metals in the soil. In addition, minerals and industrial byproducts such as alkali slag, steel slag, magnesium slag, red mud, and fly ash are also commonly used for soil improvement. However, these conditioners have low organic matter content and are prone to inducing the activation and migration of heavy metals, thus posing a risk of heavy metal pollution in the soil and creating a dual threat to human health and the ecological environment.

[0004] Existing studies have shown that for every 100 kg / hm² increase in application... 2Nitrogen fertilizer application resulted in an average decrease of 0.65 units in soil pH, highlighting the necessity of controlling soil acidification at its source, particularly by reducing nitrogen fertilizer application. Simultaneously, the application of organic fertilizer significantly increases soil organic matter and available nutrient content, enhances the presence of basic ions and organic matter functional groups in the soil, thereby strengthening the resistance to H+. + And Al 3+ Its adsorption capacity effectively inhibits and alleviates soil acidification. However, existing ordinary organic fertilizers have limited effects on improving acidified soils, and it is difficult to guarantee the stability and sustainability of the improvement effect. Therefore, providing a sustainable and stable organic fertilizer for improving acidified soils has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an environmentally friendly bio-organic fertilizer that can improve acidified soil. This bio-organic fertilizer can significantly increase soil pH, increase the content of organic matter in the soil, and has good buffering capacity and long-lasting effect, enhancing the soil's ability to retain water and fertilizer, and has a significant effect on increasing crop yield and income.

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

[0007] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 10-20 parts composite gel material, 80-100 parts decomposed poultry and livestock manure, 10-20 parts microbial inoculant, 30-50 parts modified waste tea biochar, 10-15 parts urea, 5-10 parts humic acid, 1-5 parts superphosphate, and 1-5 parts sodium carboxymethyl cellulose. The microbial inoculant is prepared by mixing *Bacillus pseudosternae*, *Pseudomonas guanylate*, and *Azotobacter beyeris* in a volume ratio of 1:1:1. The *Bacillus pseudosternae* strain number is CGMCC No. 1.7924, purchased from the China General Microbiological Culture Collection Center, with a preservation date of July 1, 2008. The *Pseudomonas guanylate* strain number is CGMCC... Strains No. 1.15627 were purchased from the China General Microbiological Culture Collection Center (CGMCC) on February 25, 2015; the *Azotobacter beylaceae* strain No. 1.5802 was also purchased from the CGMCC on June 27, 2005. All three strains can be purchased through the open catalog of the collection centers and do not require duplicate collection.

[0008] Preferably, the composite gel material is prepared by the following method:

[0009] a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60min to form a uniform mixed solution A.

[0010] b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B.

[0011] c. Mix solution A and solution B at a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, pour the crosslinked gel mixture into a specific mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material.

[0012] Preferably, the oyster shell modified biochar is prepared by the following method:

[0013] 1) Using tea residue after brewing and by-products of tea production as raw materials, the waste tea powder is obtained by drying at 100℃ and then pulverizing it through a 100-mesh sieve.

[0014] 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder.

[0015] 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar.

[0016] 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder.

[0017] 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

[0018] Preferably, the modified waste tea biochar is prepared by the following method:

[0019] A1: Take tea residues after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, and calcine them at 550℃ for 2 hours under nitrogen protection to obtain waste tea biochar.

[0020] A2: Take waste tea biochar and immerse it in a 1 mol / L NaOH solution according to the solid-liquid ratio. After ultrasonic treatment for 30 min, soak for 10-12 h, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar.

[0021] A3: Weigh out glutamic acid and ZnCl2 and dissolve them in deionized water. After ultrasonic dispersion for 5-10 min, a mixed solution is obtained. Add the alkali-treated biochar obtained from A2 to the mixed solution. After magnetic stirring for 5-6 h, the solid and liquid are separated, and the solid is dried to obtain modified waste tea biochar.

[0022] Preferably, the solid-liquid ratio in A2 is 1g:10ml.

[0023] Preferably, the ratio of glutamic acid, ZnCl2, deionized water, and alkali-treated biochar in A3 is 1g:0.5g:500ml:10g.

[0024] Preferably, the compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and cultured in an incubator at 30°C for 48 hours. One loop of the cultured strains is placed in LB liquid medium and cultured in a shaker at 30°C and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2%, and cultured at 30°C and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:2:1 to obtain the microbial agent.

[0025] Preferably, the effective viable count of the microbial agent is ≥4.0 × 10⁻⁶. 9 CFU / g. The composition of the LB liquid culture medium is: 10g tryptone, 5g yeast extract, 5g sodium chloride, pH adjusted to 7.0, deionized water to a final volume of 1L, and autoclaved for 20min.

[0026] This invention also provides a method for preparing the above-mentioned environmentally friendly bio-organic fertilizer for improving acidified soil, which includes the following steps:

[0027] Step 1: Prepare composite gel material and modified waste tea biochar respectively;

[0028] Step 2, prepare microbial inoculants;

[0029] Step 3: Mix the prepared composite gel material, modified waste tea biochar and microbial agent evenly, incubate at 30℃ for 24h, then freeze-dry under vacuum and grind into powder to obtain mixed powder.

[0030] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0031] The environmentally friendly bio-organic fertilizer for improving acidified soil obtained by this invention has an application rate of 200 kg / mu.

[0032] This invention uses oyster shell-modified biochar as raw material. The modified biochar has enhanced alkaline neutralization capacity and heavy metal adsorption performance. Furthermore, a stable gel three-dimensional network structure is formed through ionic crosslinking of carboxymethyl cellulose and sodium alginate, achieving long-term sustained release of nutrients. It can gradually release Ca2+ in acidic environments. 2+ Continuously neutralize soil H + To avoid excessive alkalization in a single step, this invention also utilizes modified waste tea biochar obtained through co-modification with glutamic acid and zinc chloride. This significantly increases the specific surface area and porosity of the biochar, and the functional groups (such as amino and carboxyl groups) contained in glutamic acid are chemically bonded to the surface of the biochar, increasing the variety of oxygen-containing functional groups. These functional groups can interact with Al in acidic soils. 3+ H + After a stable complex is formed, the modified waste tea biochar is applied to the soil. Due to the alkaline properties of the biochar itself, it can directly and rapidly increase the pH of acidified soil and reduce aluminum toxicity. Furthermore, its combination with the composite gel material of this invention achieves a rapid and long-lasting organic combination for improving acidified soil, resulting in stable and continuous improvement with good efficacy. Additionally, the glutamic acid and Zn contained in the modified waste tea biochar of this invention serve as an organic nitrogen source. 2+ As an essential trace element for plants, biochar modified by the synergistic treatment of these two elements can not only improve soil acidity but also provide abundant nutrients for crop growth, promote crop growth and development, and increase crop yield.

[0033] This invention selects three dominant bacterial strains and mixes them in a specific ratio for synergistic effects, maximizing the repair and improvement of the physicochemical properties of acidified soil. Among them, *Bacillus pseudosturcica* exhibits high acid resistance and environmental adaptability, rapidly multiplying in acidic soil to form a dominant bacterial community, and its metabolites promote the dissolution of insoluble nutrients in the soil, improving nutrient availability. *Pseudomonas guarinii* metabolites promote plant growth and accelerate the decomposition of soil organic matter, releasing plant-available nutrients and improving soil structure. *Azotobacter beyeris* converts atmospheric nitrogen into plant-available ammonia nitrogen, reducing the application of chemical nitrogen fertilizers and lowering the risk of soil acidification. The combined effect of these three strains forms a dominant bacterial community, restoring soil microbial diversity, enhancing the self-regulation capacity of the soil ecosystem, accelerating soil nutrient cycling, improving soil structure, alleviating soil compaction caused by acidification, and achieving a long-term and stable improvement effect.

[0034] The beneficial effects of this invention are:

[0035] (1) Combining composite gel material with modified waste tea biochar for acidified soil improvement has unique advantages in regulating soil pH and improving soil fertility. The two work together to achieve a combination of rapid and long-term effects in acidified soil improvement, which has stability and sustainability in improving acidified soil and has a good improvement effect.

[0036] (2) Microbial agents composed of a specific ratio of Bacillus pseudosturcium, Pseudomonas guanylate, and Azotobacter baileyi have higher activity and adaptability, and can more effectively promote the improvement of acidified soil; and composite gel materials (such as Figure 1 ) and the porous structure of modified waste tea biochar (such as Figure 2 It provides a good habitat for microorganisms, promotes the reproduction of beneficial soil microorganisms, improves soil biological activity, and further improves soil structure and fertility.

[0037] (3) This invention utilizes waste materials such as waste tea leaves and oyster shells to prepare biochar and gel materials, realizing the resource utilization of waste and reducing environmental pollution. The raw materials are widely available and inexpensive, the preparation process is simple, and it is easy to promote and apply, thereby reducing agricultural production costs. Attached Figure Description

[0038] Figure 1 The image shows the microstructure of the composite gel material prepared in this invention using SEM images.

[0039] Figure 2 The images show a comparison of SEM images of the modified waste tea biochar prepared in this invention before and after modification, where A represents the state before modification and B represents the state after modification. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to specific embodiments, but is not limited thereto. The *Bacillus pseudosturcium* strain used in the following embodiments is CGMCC No. 1.7924, purchased from the China General Microbiological Culture Collection Center, with a deposit date of July 1, 2008; the *Pseudomonas guguanense* strain is CGMCC No. 1.15627, with a deposit date of February 25, 2015; and the *Azotobacter beyerridis* strain is CGMCC No. 1.5802, with a deposit date of June 27, 2005.

[0041] Example 1

[0042] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 10 parts of composite gel material, 80 parts of decomposed poultry and livestock manure, 10 parts of microbial inoculant, 30 parts of modified waste tea biochar, 10 parts of urea, 5 parts of humic acid, 1 part of superphosphate, and 1 part of sodium carboxymethyl cellulose; the microbial inoculant is made by mixing Bacillus pseudostrongylus, Pseudomonas aeruginosa, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0043] The composite gel material was prepared using the following method:

[0044] a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60min to form a uniform mixed solution A.

[0045] b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B.

[0046] c. Mix solution A and solution B at a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, pour the crosslinked gel mixture into a specific mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material.

[0047] The oyster shell modified biochar was prepared using the following method:

[0048] 1) Using tea residue after brewing and by-products of tea production as raw materials, the waste tea powder is obtained by drying at 100℃ and then pulverizing it through a 100-mesh sieve.

[0049] 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder.

[0050] 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar.

[0051] 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder.

[0052] 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

[0053] The modified waste tea biochar was prepared using the following method:

[0054] A1: Take tea residues after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, and calcine them at 550℃ for 2 hours under nitrogen protection to obtain waste tea biochar.

[0055] A2: Take waste tea biochar and immerse it in 1 mol / L NaOH solution at a solid-liquid ratio of 1g:10ml. After ultrasonic treatment for 30 minutes, soak for 10-12 hours, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar.

[0056] A3: Weigh 1g of glutamic acid and 0.5g of ZnCl2 and dissolve them in 500ml of deionized water. After ultrasonic dispersion for 5-10min, a mixture is obtained. Add 10g of the alkali-treated biochar obtained in A2 to the mixture. Stir magnetically for 5-6h, then separate the solid and liquid. Dry the solid to obtain the modified waste tea biochar.

[0057] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0058] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0059] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0060] Step 1: Prepare composite gel material and modified waste tea biochar respectively;

[0061] Step 2, prepare microbial inoculants;

[0062] Step 3: Mix the prepared composite gel material, modified waste tea biochar and microbial agent evenly, incubate at 30℃ for 24h, then freeze-dry under vacuum and grind into powder to obtain mixed powder.

[0063] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0064] Example 2

[0065] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 15 parts of composite gel material, 90 parts of decomposed poultry and livestock manure, 15 parts of microbial inoculant, 40 parts of modified waste tea biochar, 12 parts of urea, 8 parts of humic acid, 3 parts of superphosphate, and 4 parts of sodium carboxymethyl cellulose; the microbial inoculant is made by mixing Bacillus pseudostrongylus, Pseudomonas aeruginosa, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0066] The composite gel material was prepared using the following method:

[0067] a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60min to form a uniform mixed solution A.

[0068] b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B.

[0069] c. Mix solution A and solution B at a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, pour the crosslinked gel mixture into a specific mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material.

[0070] The oyster shell modified biochar was prepared using the following method:

[0071] 1) Using tea residue after brewing and by-products of tea production as raw materials, the waste tea powder is obtained by drying at 100℃ and then pulverizing it through a 100-mesh sieve.

[0072] 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder.

[0073] 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar.

[0074] 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder.

[0075] 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

[0076] The modified waste tea biochar was prepared using the following method:

[0077] A1: Take tea residues after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, and calcine them at 550℃ for 2 hours under nitrogen protection to obtain waste tea biochar.

[0078] A2: Take waste tea biochar and immerse it in 1 mol / L NaOH solution at a solid-liquid ratio of 1g:10ml. After ultrasonic treatment for 30 minutes, soak for 10-12 hours, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar.

[0079] A3: Weigh 1g of glutamic acid and 0.5g of ZnCl2 and dissolve them in 500ml of deionized water. After ultrasonic dispersion for 5-10min, a mixture is obtained. Add 10g of the alkali-treated biochar obtained in A2 to the mixture. Stir magnetically for 5-6h, then separate the solid and liquid. Dry the solid to obtain the modified waste tea biochar.

[0080] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0081] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0082] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0083] Step 1: Prepare composite gel material and modified waste tea biochar respectively;

[0084] Step 2, prepare microbial inoculants;

[0085] Step 3: Mix the prepared composite gel material, modified waste tea biochar and microbial agent evenly, incubate at 30℃ for 24h, then freeze-dry under vacuum and grind into powder to obtain mixed powder.

[0086] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0087] Example 3

[0088] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 20 parts of composite gel material, 100 parts of decomposed poultry and livestock manure, 20 parts of microbial inoculant, 50 parts of modified waste tea biochar, 15 parts of urea, 10 parts of humic acid, 5 parts of superphosphate, and 5 parts of sodium carboxymethyl cellulose; the microbial inoculant is made by mixing Bacillus pseudostrongylus, Pseudomonas aeruginosa, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0089] The composite gel material was prepared using the following method:

[0090] a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60min to form a uniform mixed solution A.

[0091] b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B.

[0092] c. Mix solution A and solution B at a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, pour the crosslinked gel mixture into a specific mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material.

[0093] The oyster shell modified biochar was prepared using the following method:

[0094] 1) Using tea residue after brewing and by-products of tea production as raw materials, the waste tea powder is obtained by drying at 100℃ and then pulverizing it through a 100-mesh sieve.

[0095] 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder.

[0096] 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar.

[0097] 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder.

[0098] 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

[0099] The modified waste tea biochar was prepared using the following method:

[0100] A1: Take tea residues after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, and calcine them at 550℃ for 2 hours under nitrogen protection to obtain waste tea biochar.

[0101] A2: Take waste tea biochar and immerse it in 1 mol / L NaOH solution at a solid-liquid ratio of 1g:10ml. After ultrasonic treatment for 30 minutes, soak for 10-12 hours, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar.

[0102] A3: Weigh 1g of glutamic acid and 0.5g of ZnCl2 and dissolve them in 500ml of deionized water. After ultrasonic dispersion for 5-10min, a mixture is obtained. Add 10g of the alkali-treated biochar obtained in A2 to the mixture. Stir magnetically for 5-6h, then separate the solid and liquid. Dry the solid to obtain the modified waste tea biochar.

[0103] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0104] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0105] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0106] Step 1: Prepare composite gel material and modified waste tea biochar respectively;

[0107] Step 2, prepare microbial inoculants;

[0108] Step 3: Mix the prepared composite gel material, modified waste tea biochar and microbial agent evenly, incubate at 30℃ for 24h, then freeze-dry under vacuum and grind into powder to obtain mixed powder.

[0109] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0110] Comparative Example 1

[0111] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 100 parts of well-rotted poultry and livestock manure, 20 parts of microbial inoculant, 50 parts of modified waste tea biochar, 15 parts of urea, 10 parts of humic acid, 5 parts of superphosphate, and 5 parts of sodium carboxymethyl cellulose; the microbial inoculant is made by mixing Bacillus pseudosternae, Pseudomonas aeruginosa, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0112] The modified waste tea biochar was prepared using the following method:

[0113] A1: Take tea residues after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, and calcine them at 550℃ for 2 hours under nitrogen protection to obtain waste tea biochar.

[0114] A2: Take waste tea biochar and immerse it in 1 mol / L NaOH solution at a solid-liquid ratio of 1g:10ml. After ultrasonic treatment for 30 minutes, soak for 10-12 hours, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar.

[0115] A3: Weigh 1g of glutamic acid and 0.5g of ZnCl2 and dissolve them in 500ml of deionized water. After ultrasonic dispersion for 5-10min, a mixture is obtained. Add 10g of the alkali-treated biochar obtained in A2 to the mixture. Stir magnetically for 5-6h, then separate the solid and liquid. Dry the solid to obtain the modified waste tea biochar.

[0116] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0117] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0118] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0119] Step 1: Prepare modified waste tea biochar;

[0120] Step 2, prepare microbial inoculants;

[0121] Step 3: Mix the prepared modified waste tea biochar with microbial inoculant evenly, incubate at 30℃ for 24h, then freeze-dry under vacuum and grind into powder to obtain mixed powder.

[0122] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0123] This comparative example is basically the same as Example 3, except that it does not contain the composite gel material and the corresponding preparation method steps.

[0124] Comparative Example 2

[0125] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 20 parts of composite gel material, 100 parts of decomposed poultry and livestock manure, 20 parts of microbial agent, 15 parts of urea, 10 parts of humic acid, 5 parts of superphosphate, and 5 parts of sodium carboxymethyl cellulose; the microbial agent is made by mixing Bacillus pseudostearate, Pseudomonas aeruginosa, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0126] The composite gel material was prepared using the following method:

[0127] a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60min to form a uniform mixed solution A.

[0128] b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B.

[0129] c. Mix solution A and solution B at a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, pour the crosslinked gel mixture into a specific mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material.

[0130] The oyster shell modified biochar was prepared using the following method:

[0131] 1) Using tea residue after brewing and by-products of tea production as raw materials, the waste tea powder is obtained by drying at 100℃ and then pulverizing it through a 100-mesh sieve.

[0132] 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder.

[0133] 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar.

[0134] 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder.

[0135] 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

[0136] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0137] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0138] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0139] Step 1: Prepare composite gel materials separately;

[0140] Step 2, prepare microbial inoculants;

[0141] Step 3: Mix the prepared composite gel material with the microbial agent evenly, incubate at 30°C for 24 hours, then freeze-dry under vacuum and grind into powder to obtain the mixed powder.

[0142] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0143] Comparative Example 2 is basically the same as Example 3, except that it does not contain modified waste tea biochar.

[0144] Comparative Example 3

[0145] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 20 parts of composite gel material, 100 parts of decomposed poultry and livestock manure, 20 parts of microbial inoculant, 50 parts of waste tea biochar, 15 parts of urea, 10 parts of humic acid, 5 parts of superphosphate, and 5 parts of sodium carboxymethyl cellulose; the microbial inoculant is made by mixing Bacillus pseudostrongylus, Pseudomonas aeruginosa, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0146] The composite gel material was prepared using the following method:

[0147] a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60min to form a uniform mixed solution A.

[0148] b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B.

[0149] c. Mix solution A and solution B at a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, pour the crosslinked gel mixture into a specific mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material.

[0150] The oyster shell modified biochar was prepared using the following method:

[0151] 1) Using tea residue after brewing and by-products of tea production as raw materials, the waste tea powder is obtained by drying at 100℃ and then pulverizing it through a 100-mesh sieve.

[0152] 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder.

[0153] 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar.

[0154] 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder.

[0155] 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

[0156] The waste tea biochar is prepared by the following method: Take tea residue after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, heat them to 550°C at a rate of 5°C / min under nitrogen protection, and calcine them for 2 hours to obtain waste tea biochar.

[0157] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0158] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0159] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0160] Step 1: Prepare composite gel material and waste tea biochar respectively;

[0161] Step 2, prepare microbial inoculants;

[0162] Step 3: Mix the prepared composite gel material, waste tea biochar and microbial agent evenly, incubate at 30°C for 24 hours, then freeze-dry under vacuum and grind into powder to obtain mixed powder.

[0163] Step 4: Mix the remaining raw materials with the mixed powder evenly, then regranulate and dry at low temperature to obtain the final product.

[0164] Comparative Example 2 is basically the same as Example 3, except that the waste tea biochar was not modified.

[0165] Comparative Example 4

[0166] An environmentally friendly bio-organic fertilizer for improving acidified soil is made from the following raw materials in parts by weight: 100 parts of well-rotted poultry and livestock manure, 20 parts of microbial inoculant, 15 parts of urea, 10 parts of humic acid, 5 parts of superphosphate, and 5 parts of sodium carboxymethyl cellulose; the microbial inoculant is made by mixing Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter beyeris in a volume ratio of 1:1:1.

[0167] The compound microbial agent is prepared by the following method: Bacillus pseudosternae, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30℃ for 48 hours. One loop of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30℃ and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and shaken at 30℃ and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial agent.

[0168] The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

[0169] The above-mentioned method for preparing environmentally friendly bio-organic fertilizer for improving acidified soil includes the following steps:

[0170] Step 1: Prepare microbial inoculants;

[0171] Step 2: Mix the prepared microbial agent with the remaining raw materials evenly, and then regranulate and dry at low temperature to obtain the final product.

[0172] This comparative example is basically the same as Example 3, except that it does not contain composite gel material and modified waste tea biochar.

[0173] Comparative Example 5

[0174] This comparative example is basically the same as Example 3, except that the microbial agent does not contain Nitrogenobacter beyerii.

[0175] Comparative Example 6

[0176] This comparative example is basically the same as Example 3, except that the microbial agent does not contain Pseudomonas guanylate.

[0177] Comparative Example 7

[0178] This comparative example is basically the same as Example 3, except that the microbial agent does not contain Bacillus pseudostrongylus.

[0179] Field planting application trial

[0180] The environmentally friendly bio-organic fertilizers for improving acidified soil prepared in Examples 1-3 and Comparative Examples 1-7 were used in a field potato planting experiment. A potato planting base in Chongfang Town, Tancheng County, Linyi City, was selected for the experiment. The potato variety was Zhongshu No. 2. A total of 11 treatments were set up: the treatment groups of Examples 1-3 and Comparative Examples 1-7, and the conventional fertilizer control group (N:P2O5:K2O = 15:15:15). Each plot was 50 m². 2Plant in two rows on wide ridges, with a ridge width of 40cm and a ridge height of 25cm, at a planting density of 55,000 plants / hm². 2 In each treatment group, except for the control group which received conventional fertilizer, the application rate was 200 kg / mu (approximately 133 kg / mu). The conventional control group received 50 kg / mu (approximately 33 kg / mu). All fertilizers were applied as base fertilizer and incorporated into the soil before potato planting. Other conventional field management practices were the same. The basic physicochemical properties of the experimental field soil are shown in Table 1.

[0181] Table 1 Soil physicochemical properties

[0182] Yield was determined at potato harvest. Crude protein, reducing sugar, and vitamin C content were measured within 14 days of harvest.

[0183]

[0184] Starch content and nitrate content were determined. Specific test results are shown in Table 2.

[0185] Table 2. Potato yield and quality in different treatment groups

[0186]

[0187]

[0188] As can be seen from the data in Table 2 above, after using the environmentally friendly bio-organic fertilizer for improving acidified soil prepared according to the embodiments of the present invention, the yield, crude protein content, reducing sugar content, vitamin C content, and starch content of potatoes were significantly better than those of comparative examples 1-7, and the yield increase rate was more than 20.0% compared with the conventional control. This is because the environmentally friendly bio-organic fertilizer for improving acidified soil prepared according to the present invention can effectively improve the physical and chemical properties of the soil through the synergistic effect of multiple components, thereby significantly improving the soil fertility and health level. This helps to promote plant growth and development, and improve the yield and quality of crops.

[0189] After potato harvest, topsoil samples (0-30cm) were collected. Soil samples were collected for each treatment group using the S-shaped sampling method. During sampling, the soil auger was drilled to a depth of 30cm in one pass. Three replicates were collected for each treatment group, and the three replicates from the same treatment group were combined into one sample. Visible debris such as gravel and plant roots were removed. The samples were then brought back to the laboratory for determination of basic soil physicochemical properties, soil enzyme activity, and soil microbial biomass. The results are shown in Tables 3-4 below. The methods for testing soil enzyme activity were as follows: urease activity was determined using the sodium phenolate-sodium hypochlorite colorimetric method; catalase activity was determined using the potassium permanganate titration method; sucrase activity was determined using the 3,5-dinitrosalicylic acid colorimetric method; and phosphatase activity was determined using the disodium phenyl phosphate colorimetric method. Microbial biomass was determined using the fumigation extraction-volume analysis method.

[0190] Table 3 Soil physicochemical properties of different treatment groups

[0191]

[0192]

[0193] As can be seen from the data in Table 3 above, after using the environmentally friendly bio-organic fertilizer for improving acidified soil prepared in Examples 1-3 of this invention, the soil pH significantly increased, the exchangeable aluminum content decreased, and the soil microbial biomass and organic matter content significantly increased. The soil acidification was significantly improved, and the soil microbial content was significantly increased. This is because the composite gel material used in this invention, combined with modified waste tea biochar, works synergistically to achieve a combination of rapid and long-term effects in improving acidified soil. This results in stable and continuous improvement of acidified soil, with good improvement effects.

[0194] Table 4 Soil enzyme activities in different treatment groups

[0195]

[0196]

[0197] As can be seen from the data in Table 4 above, the environmentally friendly bio-organic fertilizer for improving acidified soil prepared in Examples 1-3 of this invention significantly increased soil enzyme activity. This is due to the synergistic effect of multiple components after application to the soil, leading to the proliferation of a large number of beneficial microorganisms, the formation of a dominant microbial community, restoration of soil microbial diversity, enhancement of the soil ecosystem's self-regulation capacity, acceleration of soil nutrient cycling, improvement of soil structure, and alleviation of compaction caused by acidification. The overall effect is increased soil enzyme activity and a greater number of soil microorganisms. Reducing or altering any component of the bio-organic fertilizer of this invention will result in the disappearance or weakening of the corresponding effect.

[0198] 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. An environmentally friendly bio-organic fertilizer for improving acidified soil, characterized in that, It is made from the following raw materials in parts by weight: 10-20 parts composite gel material, 80-100 parts decomposed poultry and livestock manure, 10-20 parts microbial inoculant, 30-50 parts modified waste tea biochar, 10-15 parts urea, 5-10 parts humic acid, 1-5 parts superphosphate, and 1-5 parts sodium carboxymethyl cellulose; the microbial inoculant is prepared by mixing *Bacillus pseudostrongylus*, *Pseudomonas guanyense*, and *Azotobacter beyeris* in a volume ratio of 1:1:1; the *Bacillus pseudostrongylus* strain number is CGMCC No. 1.7924, purchased from the China General Microbiological Culture Collection Center, with a preservation date of July 1, 2008; the *Pseudomonas guanyense* strain number is CGMCC No. 1.15627, purchased from the China General Microbiological Culture Collection Center, with a preservation date of February 25, 2015; the *Azotobacter beyeris* strain number is CGMCC... No. 1.5802, purchased from the China General Microbiological Culture Collection Center, with a preservation date of June 27, 2005; The composite gel material was prepared using the following method: a. Add 5g of oyster shell modified biochar to 100ml of 2wt% carboxymethyl cellulose aqueous solution and stir thoroughly. Then, while stirring, slowly add 100ml of 4wt% sodium alginate aqueous solution and continue stirring for 30-60 minutes to form a uniform mixed solution A. b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), prepare a gluconolactone solution with a concentration of 1% (w / v), and mix the gluconolactone solution and the CaCO3 suspension at a volume ratio of 1:1 to obtain mixed solution B. c. Mix solution A and solution B at a volume ratio of 1:1, stir and cross-link at room temperature for 6 hours, pour the cross-linked gel mixture into a mold to form it, let it stand at room temperature for 24 hours, freeze dry under vacuum and pulverize to obtain the composite gel material. The modified waste tea biochar was prepared using the following method: A1: Take tea residues after brewing, waste tea products such as tea production by-products, dry them, transfer them to a muffle furnace, and calcine them at 550℃ for 2 hours under nitrogen protection to obtain waste tea biochar. A2: Take waste tea biochar and immerse it in a 1 mol / L NaOH solution according to the solid-liquid ratio. After ultrasonic treatment for 30 min, soak for 10-12 h, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar. A3: Weigh out glutamic acid and ZnCl2 and dissolve them in deionized water. After ultrasonic dispersion for 5-10 min, a mixed solution is obtained. Add the alkali-treated biochar obtained from A2 to the mixed solution. After magnetic stirring for 5-6 h, the solid and liquid are separated, and the solid is dried to obtain modified waste tea biochar.

2. The environmentally friendly bio-organic fertilizer for improving acidified soil according to claim 1, characterized in that, The oyster shell modified biochar was prepared using the following method: 1) Waste tea powder is obtained by drying tea residue and by-products of tea production at 100℃ and then pulverizing them through a 100-mesh sieve. 2) Take 10g of waste tea powder and add it to 100ml of 1mol / L KOH solution. Stir magnetically for 24h and then dry to obtain pretreated waste tea powder. 3) The pretreated waste tea powder was transferred into a muffle furnace and calcined at 550°C for 2 hours under anaerobic conditions. The product was then acid-washed to neutral, dried, and ground into powder to obtain biochar. 4) Wash and dry the oyster shells and break them into small pieces. Then, calcine them in a muffle furnace at 500°C for 2 hours to obtain oyster shell powder. 5) Mix the obtained biochar and oyster shell powder at a mass ratio of 3:1 to obtain a mixture. Then add deionized water at a solid-liquid ratio of 1g:30ml. Stir the mixture magnetically at room temperature for 6-8 hours. Heat the mixture to 160-180℃ and react for 10-12 hours. Cool to room temperature, filter and dry to obtain oyster shell modified biochar.

3. The environmentally friendly bio-organic fertilizer for improving acidified soil according to claim 1, characterized in that, The solid-liquid ratio in A2 is 1g:10ml.

4. The environmentally friendly bio-organic fertilizer for improving acidified soil according to claim 1, characterized in that, The ratio of glutamic acid, ZnCl2, deionized water, and alkali-treated biochar in A3 is 1g:0.5g:500ml:10g.

5. The environmentally friendly bio-organic fertilizer for improving acidified soil according to claim 1, characterized in that, The microbial inoculant is prepared by the following method: Bacillus pseudosturcium, Pseudomonas guanylate, and Azotobacter baileyi are thawed and activated separately, strewn onto plates, and incubated at 30°C for 48 hours. One loopful of the cultured strains is placed in LB liquid medium and shaken in a shaker at 30°C and 200 rpm for 36 hours to obtain three seed liquids. The seed liquids of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation rate of 2% and incubated at 30°C and 200 rpm for 72 hours to obtain fermentation broth. The three fermentation broths are mixed in a volume ratio of 1:1:1 to obtain the microbial inoculant.

6. The environmentally friendly bio-organic fertilizer for improving acidified soil according to claim 5, characterized in that, The effective viable count of the microbial agent is ≥4.0×10⁻⁶. 9 CFU / g.

7. A method for preparing an environmentally friendly bio-organic fertilizer for improving acidified soil according to any one of claims 1-6, characterized in that, It includes the following steps: Step 1: Prepare composite gel material and modified waste tea biochar respectively; Step 2, prepare microbial inoculants; Step 3: Mix the prepared composite gel material, modified waste tea biochar and microbial agent evenly, incubate at 30℃ for 24h, then freeze-dry under vacuum and grind into powder to obtain mixed powder. Step 4: Mix the remaining raw materials with the mixed powder evenly, then re-granulate and dry at low temperature to obtain the final product.

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