Environment-friendly bio-organic fertilizer for improving acidified soil and preparation method of environment-friendly bio-organic fertilizer

Abstract

The invention discloses an environment-friendly bio-organic fertilizer for improving acidified soil and a preparation method of the environment-friendly bio-organic fertilizer, and belongs to the technical field of organic fertilizers. The bio-organic fertilizer is prepared from the following raw materials in parts by weight: 10-20 parts of a composite gel material, 80-100 parts of decomposed livestock and poultry manure, 10-20 parts of a microbial agent, 30-50 parts of modified waste tea biochar, 10-15 parts of urea, 5-10 parts of humic acid, 1-5 parts of calcium superphosphate and 1-5 parts of sodium carboxymethyl cellulose, the microbial agent is prepared by mixing bacillus pseudofirmus, pseudomonas oryzae and azotobacter beijerinckii according to the volume ratio of 1: 1: 1. The bio-organic fertilizer can remarkably improve the pH of soil and increase the content of organic matters in the soil, has good buffering capacity and long-term effect, enhances the water and fertilizer retention capacity of the soil, and has a remarkable effect of increasing both production and income of crops.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural organic fertilizers, and in particular to an environmentally friendly biological organic fertilizer for improving acidified soil and a preparation method thereof. Background Art

[0002] Soil acidification is a natural process that accompanies soil generation and development. It is mainly caused by the dissociation of free carbonic acid and organic acid in the soil to produce hydrogen ions (H + ), which is manifested as an increase in soil exchangeable acid and a decrease in pH. Natural and human factors such as acid deposition, leaching and loss of mineral ions, and excessive application of fertilizers accelerate the process of soil acidification. With the development of industrialization and agricultural intensification, the problem of soil acidification has become increasingly serious, leading to a decline in soil fertility, nutrient imbalance, and accumulation of harmful substances, which seriously affects the yield and quality of crops. Soil acidification has become one of the most serious land degradation problems in the global agricultural system, with up to 30% of the world's arable land affected by acidification. Soil acidification first affects the effectiveness of soil nutrients; at the same time, soil acidification will accelerate the weathering of primary and secondary aluminum-containing minerals in the soil and release a large amount of aluminum ions, forming aluminum-containing compounds that can be absorbed by plants. Long-term and excessive absorption of aluminum ions by plants will cause crop poisoning or death, resulting in a large reduction in crop yields or even a complete loss of crops; secondly, soil acidification will affect the activity of soil enzymes, thereby affecting the absorption of nutrients by crops; finally, soil acidification will also lead to a large loss of alkaline base ions such as calcium and magnesium, which will lead to the deterioration of soil physical and chemical properties, change soil structure, and reduce soil buffering performance.

[0003] In order to effectively deal with the problem of soil acidification, various soil conditioners such as lime, organic materials, minerals and industrial by-products are widely used in the remediation of acidified soil. Among them, lime conditioners such as quicklime, slaked lime and limestone have the advantages of fast effect and good improvement effect. Studies have shown that the pH value of acidic soil with a soil pH of 4.84 increased by 32% after applying a certain amount of lime. However, long-term and large-scale application of lime may lead to problems such as soil compaction, re-acidification, lack of nutrients such as calcium, magnesium, phosphorus and potassium, and reduced soil microbial diversity. Organic materials such as livestock and poultry manure, crop residues, and green manure are easy to obtain and have low production costs, and are more widely used in practical applications. However, their impact on soil pH is uncertain, and the application of manure may cause excessive heavy metals in the soil. In addition, minerals and industrial by-products such as alkali slag, steel slag, magnesium slag, red mud, and fly ash are also often used for soil improvement. However, such conditioners have a low organic matter content and are prone to induce the activation and migration of heavy metals, thereby causing the risk of soil heavy metal pollution, posing a dual threat to human health and the ecological environment.

[0004] Studies have shown that every additional 100kg / hm 2For nitrogen fertilizers, the average soil pH decreased by 0.65 units. This result emphasizes the necessity of controlling soil acidification at the source, especially reducing the application of nitrogen fertilizers. At the same time, applying organic fertilizers can significantly increase the content of soil organic matter and available nutrients, increase the base ions and organic functional groups in the soil, and thus enhance the adsorption capacity for H + and Al 3+ , effectively inhibiting and alleviating soil acidification. However, the existing ordinary organic fertilizers have limited improvement effects on acidified soils and it is difficult to ensure the stability and sustainability of the improvement effects. Therefore, providing an organic fertilizer for continuously and stably improving acidified soils has become a technical problem to be solved urgently. Summary of the Invention

[0005] The purpose of the present invention is to provide an environment-friendly biological organic fertilizer for improving acidified soils. This biological organic fertilizer can significantly increase the soil pH, increase the content of organic matter in the soil, and has good buffering capacity and long-term effectiveness, enhancing the soil's water and fertilizer retention capacity, and having a significant effect on increasing crop yields and incomes.

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

[0007] An environment-friendly biological organic fertilizer for improving acidified soils is made from the following raw materials in parts by weight: 10 - 20 parts of composite gel material, 80 - 100 parts of decomposed livestock and poultry manure, 10 - 20 parts of microbial inoculant, 30 - 50 parts of modified waste tea biochar, 10 - 15 parts of urea, 5 - 10 parts of humic acid, 1 - 5 parts of superphosphate, and 1 - 5 parts of sodium carboxymethylcellulose; the microbial inoculant is made by mixing Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii in a volume ratio of 1:1:1; the strain number of Bacillus pseudofirmus is CGMCC No.1.7924, purchased from the China General Microbiological Culture Collection Center, and the preservation date is July 1, 2008; the strain number of Pseudomonas gunnii is CGMCC No.1.15627, purchased from the China General Microbiological Culture Collection Center, and the preservation date is February 25, 2015; the strain number of Azotobacter beijerinckii is CGMCC No.1.5802, purchased from the China General Microbiological Culture Collection Center, and the preservation date is June 27, 2005. The above three strains can be purchased through the open catalog of the preservation center and there is no need for repeated preservation.

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

[0009] a. Add 5 g of oyster shell modified biochar to 100 ml of 2 wt% sodium carboxymethylcellulose aqueous solution and stir well. Then, slowly add 100 ml of 4 wt% sodium alginate aqueous solution under stirring and continue stirring for 30 - 60 min 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 glucono-delta-lactone solution with a concentration of 1% (w / v), and mix the glucono-delta-lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B;

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

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

[0013] 1) Using the brewed tea residue and tea production by-products as raw materials, dry at 100 °C and then pulverize and pass through a 100-mesh sieve to obtain waste tea powder;

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

[0015] 3) Transfer the above pretreated waste tea powder into a muffle furnace, under anaerobic conditions, calcine at 550 °C for 2 h, then wash the product with acid until neutral, dry and grind it into powder to obtain biochar;

[0016] 4) Wash and dry the oyster shells and break them into small pieces, then transfer them to a muffle furnace and calcine at 500 °C for 2 h to obtain oyster shell powder;

[0017] 5) Mix the obtained biochar and oyster shell powder evenly according to a mass ratio of 3:1, then add deionized water according to a solid-liquid ratio of 1 g:30 ml, stir magnetically at room temperature for 6 - 8 h, then heat the mixed solution to 160 - 180 °C and react for 10 - 12 h, and then cool to room temperature, filter and dry to obtain the oyster shell modified biochar.

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

[0019] A1: Take the brewed tea residue, tea production by-products and other waste tea, dry it and then transfer it to a muffle furnace, heat it to 550 °C under nitrogen protection and calcine for 2 h to obtain waste tea biochar;

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

[0021] A3: Weigh glutamic acid and ZnCl₂ separately and dissolve them in deionized water. After ultrasonic dispersion for 5 - 10 min, a mixed solution is obtained. Add the alkali - treated biochar obtained in A2 to the mixed solution, stir magnetically for 5 - 6 h, then perform solid - liquid separation, and dry the solid to obtain the modified waste tea biochar.

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

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

[0024] Preferably, the composite microbial inoculant is prepared by the following method: Thaw and activate Bacillus pseudofirmus, Pseudomonas guangdongensis, and Azotobacter beijerinckii respectively. After streak - plating on a plate, culture them in an incubator at 30 °C for 48 h. Take a loop of the cultured strain and place it in an LB liquid medium, and culture it in a shaker at 30 °C and 200 r / min for 36 h to obtain three seed solutions. Inoculate the seed solutions of the three strains into 200 mL of TSB liquid medium at an inoculation amount of 2% respectively, and culture them at 30 °C and 200 r / min for 72 h to obtain fermentation broths; mix the three fermentation broths according to a volume ratio of 1:2:1 to obtain the microbial inoculant.

[0025] Preferably, the effective viable count of the microbial inoculant ≥ 4.0×10 9 CFU / g. The composition of the LB liquid medium is: 10 g of tryptone, 5 g of yeast extract, 5 g of sodium chloride, adjust the pH to 7.0, make up the volume to 1 L with deionized water, and sterilize it by high - pressure steam for 20 min.

[0026] The present invention also provides a preparation method of the above - mentioned environment - friendly biological organic fertilizer for improving acidified soil, which includes the following steps:

[0027] Step 1, prepare the composite gel material and the modified waste tea biochar respectively;

[0028] Step 2, prepare the microbial inoculant;

[0029] Step 3, mix the prepared composite gel material, modified waste tea biochar, and microbial inoculant evenly, culture them at 30 °C for 24 h, then perform vacuum freeze - drying and grind them into powder to obtain a mixed powder;

[0030] Step 4, mix the remaining raw materials with the mixed powder evenly and re - granulate and dry them at low temperature to obtain the product.

[0031] The dosage of the environment - friendly biological organic fertilizer for improving acidified soil obtained by the present invention is 200 kg / mu.

[0032] The present invention uses oyster shell modified biochar as a raw material. After modification with oyster shells, the alkaline neutralization ability and heavy metal adsorption performance of the biochar are enhanced. Further, a stable three-dimensional gel network structure is formed through the ionic crosslinking of carboxymethyl cellulose and sodium alginate, achieving long-term slow release of nutrients and allowing for the gradual release of Ca in an acidic environment. 2+ , continuously neutralizing soil H + , and avoiding excessive alkalization at one time. The present invention also uses modified waste tea biochar obtained by co-modifying with glutamic acid and zinc chloride. The specific surface area and porosity of the biochar are significantly increased, and the functional groups contained in glutamic acid (such as amino groups and carboxyl groups) are bonded to the surface of the biochar through chemical bonds, increasing the types of oxygen-containing functional groups. These functional groups can form stable complexes with Al 3+ , H + , etc. in acidic soil. After applying the modified waste tea biochar to the soil, due to the alkaline nature of the biochar itself, it can directly and rapidly increase the pH of acidified soil and reduce the harm of aluminum toxicity; when combined with the composite gel material of the present invention, it realizes the organic combination of rapid and long-term effects in the improvement of acidified soil, has stability and persistence in the improvement of acidified soil, and has good improvement effects; moreover, the glutamic acid contained in the modified waste tea biochar of the present invention serves as an organic nitrogen source, and Zn 2+ serves as an essential trace element for plants. The biochar after the synergistic modification treatment can not only improve soil acidity but also provide rich nutrients for the growth of crops, promote crop growth and development, and increase crop yields.

[0033] The present invention screens 3 dominant strains and uses them in a specific ratio in a synergistic manner to repair and improve the physical and chemical properties of acidified soil to the greatest extent. Among them, Bacillus pseudofirmus has high acid tolerance and environmental adaptability, can rapidly reproduce in acidic soil to form a dominant flora, and its metabolites can promote the dissolution of insoluble nutrients in the soil and improve nutrient availability; the metabolites of Pseudomonas gunnii can promote plant growth and at the same time accelerate the decomposition of soil organic matter, release nutrients available to plants, and improve soil structure; Azotobacter beijerinckii converts nitrogen in the air into ammonia nitrogen available to plants, reduces the application of chemical nitrogen fertilizers, and reduces the risk of soil acidification; the three act together to form a dominant flora, restore soil microbial diversity, enhance the self-regulating ability of the soil ecosystem, accelerate soil nutrient cycling, improve soil structure, relieve the compaction problem caused by acidification, and form a long-term stable improvement effect.

[0034] The beneficial effects of the present invention are:

[0035] (1) The combination of composite gel material and modified waste tea biochar is used for acidified soil improvement. This combination has unique advantages in regulating soil pH and improving soil fertility. The two work synergistically to achieve the organic combination of quick-acting and long-acting acidified soil improvement, showing stability and sustainability in acidified soil improvement with good improvement effects.

[0036] (2) The microbial inoculant composed of specific proportions of Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii has higher activity and adaptability, and can more effectively promote the improvement of acidified soil. Moreover, the porous structures of the composite gel material (such as Figure 1 ) and the modified waste tea biochar (such as Figure 2 ) provide good habitats for microorganisms, promote the reproduction of beneficial soil microorganisms, improve soil biological activity, and further improve soil structure and fertility.

[0037] (3) The present invention uses waste materials such as waste tea and oyster shells to prepare biochar and gel materials, realizing the resource utilization of waste materials and reducing environmental pollution. The raw materials are widely sourced and low-cost, and the preparation process is simple, easy to promote and apply, reducing agricultural production costs. Description of the Drawings

[0038] Figure 1 SEM micrograph of the microscopic morphology of the composite gel material prepared by the present invention;

[0039] Figure 2 SEM comparison diagram of the modified waste tea biochar before and after modification prepared by the present invention, where A is before modification and B is after modification. Detailed Embodiments

[0040] The technical solutions of the present invention will be further described below in conjunction with specific embodiments, but not limited thereto. The strain number of Bacillus pseudofirmus used in the following embodiments is CGMCC No. 1.7924, purchased from the China General Microbiological Culture Collection Center, and the preservation date is July 1, 2008; the strain number of Pseudomonas gunnii is CGMCC No. 1.15627, and the preservation date is February 25, 2015; the strain number of Azotobacter beijerinckii is CGMCC No. 1.5802, and the preservation date is June 27, 2005.

[0041] Example 1

[0042] An environment-friendly biological organic fertilizer for improving acidified soil, which is made from the following raw materials in parts by weight: 10 parts of composite gel material, 80 parts of decomposed livestock and poultry manure, 10 parts of microbial inoculum, 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 carboxymethylcellulose; the microbial inoculum is made by mixing Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii in a volume ratio of 1:1:1.

[0043] The composite gel material is prepared by the following method:

[0044] a. Add 5 g of oyster shell modified biochar to 100 ml of 2 wt% sodium carboxymethylcellulose aqueous solution and stir well. Then, slowly add 100 ml of 4 wt% sodium alginate aqueous solution under stirring, and continue to stir for 30 - 60 min 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), and prepare a glucono - δ - lactone solution with a concentration of 1% (w / v). Mix the glucono - δ - lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B;

[0046] c. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:1, stir and cross - link at room temperature for 6 hours, then pour the cross - linked gel mixture into a specific mold to make it form. After standing at room temperature for 24 hours, vacuum freeze - dry and crush to obtain the composite gel material.

[0047] The oyster shell modified biochar is prepared by the following method:

[0048] 1) Use the brewed tea residues and tea production by - products as raw materials, dry at 100 °C, crush and pass through a 100 - mesh sieve to obtain waste tea powder;

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

[0050] 3) Transfer the above pretreated waste tea powder into a muffle furnace, under anaerobic conditions, calcine at 550 °C for 2 h, then wash the product with acid until neutral, dry and grind into powder to obtain biochar;

[0051] 4) Wash and dry the oyster shells and crush them into small pieces, then transfer them into a muffle furnace and calcine at 500 °C for 2 h to obtain oyster shell powder;

[0052] 5) Mix the obtained biochar and oyster shell powder evenly at a mass ratio of 3:1 to obtain a mixture, then add deionized water at a solid-liquid ratio of 1 g:30 ml, magnetically stir and react at room temperature for 6 - 8 h, heat the mixed solution to 160 - 180 °C and react for 10 - 12 h, and then cool to room temperature, filter and dry to obtain oyster shell-modified biochar.

[0053] The modified waste tea biochar is prepared by the following method:

[0054] A1: Take waste tea such as brewed tea residues and tea production by-products, dry them and transfer them to a muffle furnace, heat up to 550 °C under nitrogen protection and calcine for 2 h to obtain waste tea biochar;

[0055] A2: Immerse the waste tea biochar in 1 mol / L NaOH solution at a solid-liquid ratio of 1 g:10 ml, ultrasonically treat for 30 min, soak for 10 - 12 h, filter, and wash the solid product with water until neutral to obtain alkali-treated biochar;

[0056] A3: Weigh 1 g of glutamic acid and 0.5 g of ZnCl2 respectively, dissolve them in 500 ml of deionized water, ultrasonically disperse for 5 - 10 min to obtain a mixed solution, add 10 g of the alkali-treated biochar obtained in A2 to the mixed solution, magnetically stir for 5 - 6 h, separate the solid and liquid, and dry the solid to obtain modified waste tea biochar.

[0057] The composite microbial inoculant is prepared by the following method: Thaw and activate Bacillus pseudofirmus, Pseudomonas guangdongensis, and Azotobacter beijerinckii respectively, perform plate streaking and culture in an incubator at 30 °C for 48 h, take a loop of the cultured strain and place it in an LB liquid medium, and shake culture at 30 °C and 200 r / min in a shaker for 36 h to obtain three seed solutions. Inoculate the seed solutions of the three strains into 200 mL of TSB liquid medium at an inoculation amount of 2% respectively, shake culture at 30 °C and 200 r / min for 72 h to obtain fermentation broths; Mix the three fermentation broths in a volume ratio of 1:1:1 to obtain the microbial inoculant.

[0058] The effective viable count of the microbial inoculant ≥ 4.0×10 9 CFU / g.

[0059] The preparation method of the above-mentioned environment-friendly biological organic fertilizer for improving acidified soil includes the following steps:

[0060] Step 1, prepare the composite gel material and the modified waste tea biochar respectively;

[0061] Step 2, prepare the microbial inoculant;

[0062] Step 3: Mix the prepared composite gel material, modified waste tea biochar, and microbial inoculant evenly. After culturing at 30 °C for 24 h, vacuum freeze-dry and grind into powder to obtain a mixed powder.

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

[0064] Example 2

[0065] An environment-friendly biological 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 livestock and poultry 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 carboxymethylcellulose; the microbial inoculant is made by mixing Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii in a volume ratio of 1:1:1.

[0066] The composite gel material is prepared by the following method:

[0067] a. Add 5 g of oyster shell modified biochar to 100 ml of 2 wt% sodium carboxymethylcellulose aqueous solution and stir evenly. Then, slowly add 100 ml of 4 wt% sodium alginate aqueous solution under stirring, and continue stirring for 30 - 60 min 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), and prepare a glucono-δ-lactone solution with a concentration of 1% (w / v). Mix the glucono-δ-lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B.

[0069] c. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:1, stir and crosslink at room temperature for 6 h, then pour the crosslinked gel mixture into a specific mold to form it. After standing at room temperature for 24 h, vacuum freeze-dry and crush to obtain the composite gel material.

[0070] The oyster shell modified biochar is prepared by the following method:

[0071] 1) Use the brewed tea residue and tea production by-products as raw materials, dry at 100 °C and then crush and pass through a 100-mesh sieve to obtain waste tea powder.

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

[0073] 3) Transfer the above pretreated waste tea powder into a muffle furnace. Under anaerobic conditions, calcine it at 550 °C for 2 h. Then, wash the product with acid until it is neutral, dry it, and grind it into powder to obtain biochar.

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

[0075] 5) Mix the obtained biochar and oyster shell powder evenly according to a mass ratio of 3:1 to obtain a mixture. Then, add deionized water according to a solid-liquid ratio of 1 g:30 ml. After magnetic stirring at room temperature for 6 - 8 h, heat the mixed solution to 160 - 180 °C and react for 10 - 12 h. Then, cool it to room temperature, filter it, and dry it to obtain oyster shell modified biochar.

[0076] The modified waste tea biochar is prepared by the following method:

[0077] A1: Take waste tea such as brewed tea residues and tea production by-products, dry them, and transfer them into a muffle furnace. Under nitrogen protection, heat them up to 550 °C and calcine them for 2 h to obtain waste tea biochar.

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

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

[0080] The composite microbial inoculant is prepared by the following method: Thaw and activate Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii respectively. After plate streaking, culture them in an incubator at 30 °C for 48 h. Take a loop of the cultured strain and place it in an LB liquid medium, and shake culture it in a shaker at 30 °C and 200 r / min for 36 h to obtain three seed solutions. Inoculate the seed solutions of the three strains into 200 mL of TSB liquid medium respectively at an inoculation amount of 2%, and shake culture them at 30 °C and 200 r / min for 72 h to obtain fermentation broths; Mix the three fermentation broths according to a volume ratio of 1:1:1 to obtain the microbial inoculant.

[0081] The effective viable count of the microbial inoculant ≥ 4.0×10 9 CFU / g.

[0082] The preparation method of the above-mentioned environment-friendly biological organic fertilizer for improving acidified soil includes the following steps:

[0083] Step 1, prepare a composite gel material and a modified waste tea biochar respectively;

[0084] Step 2, prepare a microbial inoculant;

[0085] Step 3, mix the prepared composite gel material, modified waste tea biochar and microbial inoculant evenly, cultivate at 30 °C for 24 h, then vacuum freeze-dry and grind into powder to obtain a mixed powder;

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

[0087] Example 3

[0088] An environment-friendly biological organic fertilizer for improving acidified soil is made from the following raw materials by weight: 20 parts of composite gel material, 100 parts of decomposed livestock and poultry 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 carboxymethylcellulose; the microbial inoculant is made by mixing Bacillus pseudofirmus, Pseudomonas gunellae, and Azotobacter beijerinckii in a volume ratio of 1:1:1.

[0089] The composite gel material is prepared by the following method:

[0090] a. Add 5 g of oyster shell modified biochar to 100 ml of 2 wt% sodium carboxymethylcellulose aqueous solution and stir evenly. Then, slowly add 100 ml of 4 wt% sodium alginate aqueous solution under stirring, and continue stirring for 30 - 60 min 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 glucono-delta-lactone solution with a concentration of 1% (w / v), and mix the glucono-delta-lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B;

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

[0093] The oyster shell modified biochar is prepared by the following method:

[0094] 1) Using the brewed tea residues and tea production by-products as raw materials, they are dried at 100 °C and then crushed and sieved through a 100-mesh sieve to obtain waste tea powder;

[0095] 2) Take 10 g of the waste tea powder and add it to 100 ml of 1 mol / L KOH solution. After magnetic stirring for 24 h, it is dried to obtain pretreated waste tea powder;

[0096] 3) Transfer the above pretreated waste tea powder into a muffle furnace. Under anaerobic conditions, it is calcined at 550 °C for 2 h. Then, the product is pickled to neutral, dried and ground into powder to obtain biochar;

[0097] 4) Wash the oyster shells, dry them and crush them into small pieces, and then transfer them into a muffle furnace and calcine at 500 °C for 2 h to obtain oyster shell powder;

[0098] 5) Mix the obtained biochar and oyster shell powder evenly according to a mass ratio of 3:1 to obtain a mixture. Then, according to a solid-liquid ratio of 1 g:30 ml, add deionized water. After magnetic stirring at room temperature for 6 - 8 h, the mixed solution is heated to 160 - 180 °C and reacted for 10 - 12 h, and then cooled to room temperature, filtered and dried to obtain oyster shell modified biochar.

[0099] The modified waste tea biochar is prepared by the following method:

[0100] A1: Take the waste tea such as brewed tea residues and tea production by-products, dry them and transfer them into a muffle furnace. Under nitrogen protection, heat it up to 550 °C and calcine for 2 h to obtain waste tea biochar;

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

[0102] A3: Weigh 1 g of glutamic acid and 0.5 g of ZnCl2 respectively and dissolve them in 500 ml of deionized water. After ultrasonic dispersion for 5 - 10 min, a mixed solution is obtained. Add 10 g of the alkali-treated biochar obtained in A2 to the mixed solution, magnetic stir for 5 - 6 h, then carry out solid-liquid separation, and dry the solid to obtain modified waste tea biochar.

[0103] The composite microbial agent is prepared by the following method: Bacillus pseudofirmus, Pseudomonas guineensis and Azotobacter beijerinckii are thawed and activated respectively, and a plate is streaked and then cultured in a 30°C incubator for 48 hours, a loop of the cultured strain is taken into an LB liquid culture medium, and the culture is placed in a shaking incubator at 30°C and 200 r / min for 36 hours to obtain three seed liquids, and the seed liquids of the three strains are inoculated into 200 mL of TSB liquid culture medium at an inoculation amount of 2% respectively, and the culture is shaken at 30°C and 200 r / min for 72 hours to obtain fermentation liquid; and the three fermentation liquids 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 9 CFU / g.

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

[0106] Step 1, preparing a composite gel material and modified waste tea biochar respectively;

[0107] Step 2, preparing a microbial agent;

[0108] Step 3, the prepared composite gel material, modified waste tea biochar and microbial agent are evenly mixed, cultured at 30° C. for 24 hours, vacuum freeze-dried and ground into powder to obtain a mixed powder;

[0109] Step 4, the remaining raw materials are mixed with the mixed powder evenly, and re-granulated and low-temperature dried to obtain.

[0110] Comparative Example 1

[0111] An environmentally friendly biological organic fertilizer for improving acidified soil is prepared from the following raw materials in parts by weight: 100 parts of decomposed poultry and livestock manure, 20 parts of microbial agents, 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 agent is prepared by mixing Bacillus pseudofirmus, Pseudomonas guineensis, and Azotobacter beijerinckii in a volume ratio of 1:1:1.

[0112] The modified waste tea biochar is prepared by the following method:

[0113] A1: Take the tea residue after brewing, tea production by-products and other waste tea, dry them and transfer them into a muffle furnace, heat them to 550℃ under nitrogen protection and calcine them for 2h to obtain waste tea biochar;

[0114] A2: Immerse the waste tea biochar in 1 mol / L NaOH solution according to the solid-liquid ratio of 1 g:10 ml, ultrasonically treat for 30 min, soak for 10 - 12 h, filter, and wash the solid product with water until neutral to obtain the alkali-treated biochar;

[0115] A3: Weigh 1 g of glutamic acid and 0.5 g of ZnCl2 respectively, dissolve them in 500 ml of deionized water, ultrasonically disperse for 5 - 10 min to obtain a mixed solution. Add 10 g of the alkali-treated biochar obtained in A2 to the mixed solution, magnetically stir for 5 - 6 h, then separate the solid and liquid, and dry the solid to obtain the modified waste tea biochar.

[0116] The composite microbial inoculant is prepared by the following method: Thaw and activate Bacillus pseudofirmus, Pseudomonas guangdongensis, and Azotobacter beijerinckii respectively. After plate streaking, culture them in an incubator at 30 °C for 48 h. Take a loop of the cultured strain and place it in an LB liquid medium, and oscillate and culture it in a shaker at 30 °C and 200 r / min for 36 h to obtain three seed solutions. Inoculate the seed solutions of the three strains into 200 mL of TSB liquid medium respectively at an inoculation amount of 2%, and oscillate and culture at 30 °C and 200 r / min for 72 h to obtain fermentation broths; Mix the three fermentation broths according to the volume ratio of 1:1:1 to obtain the microbial inoculant.

[0117] The effective viable count of the microbial inoculant ≥ 4.0×10 9 CFU / g.

[0118] The preparation method of the above-mentioned environment-friendly biological organic fertilizer for improving acidified soil includes the following steps:

[0119] Step 1, prepare the modified waste tea biochar;

[0120] Step 2, prepare the microbial inoculant;

[0121] Step 3, mix the prepared modified waste tea biochar and the microbial inoculant evenly, culture at 30 °C for 24 h, then vacuum freeze-dry and grind into powder to obtain a mixed powder;

[0122] Step 4, mix the remaining raw materials and the mixed powder evenly and regranulate and dry at low temperature to obtain the product.

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

[0124] Comparative Example 2

[0125] An environment-friendly biological organic fertilizer for improving acidified soil, which is made from the following raw materials in parts by weight: 20 parts of composite gel material, 100 parts of decomposed livestock and poultry manure, 20 parts of microbial inoculum, 15 parts of urea, 10 parts of humic acid, 5 parts of superphosphate, and 5 parts of sodium carboxymethylcellulose; the microbial inoculum is made by mixing Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii in a volume ratio of 1:1:1.

[0126] The composite gel material is prepared by the following method:

[0127] a, Add 5g of oyster shell modified biochar to 100ml of 2wt% sodium carboxymethylcellulose aqueous solution and stir well. Then, slowly add 100ml of 4wt% sodium alginate aqueous solution under stirring, and continue to stir 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), and prepare a glucono - δ - lactone solution with a concentration of 1% (w / v). Mix the glucono - δ - lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B;

[0129] c, Mix the mixed solution A and the mixed solution B in a volume ratio of 1:1, stir and cross - link at room temperature for 6 hours, then pour the cross - linked gel mixture into a specific mold to make it form. After standing at room temperature for 24 hours, vacuum freeze - dry and pulverize to obtain the composite gel material.

[0130] The oyster shell modified biochar is prepared by the following method:

[0131] 1) Using the brewed tea residue and tea production by - products as raw materials, dry at 100℃ and then pulverize and pass through a 100 - mesh sieve to obtain waste tea powder;

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

[0133] 3) Transfer the above - mentioned pretreated waste tea powder into a muffle furnace, under anaerobic conditions, calcine at 550℃ for 2h, then wash the product with acid until neutral, dry and grind it into powder to obtain biochar;

[0134] 4) Wash and dry the oyster shells and crush them into small pieces, then transfer them into a muffle furnace and calcine at 500℃ for 2h to obtain oyster shell powder;

[0135] 5) Mix the obtained biochar and oyster shell powder evenly according to a mass ratio of 3:1 to obtain a mixture, then add deionized water according to a solid-liquid ratio of 1 g:30 ml, magnetically stir and react at room temperature for 6-8 h, heat the mixed solution to 160-180 °C and react for 10-12 h, then cool to room temperature, filter and dry to obtain oyster shell-modified biochar.

[0136] The composite microbial inoculant is prepared by the following method: Thaw and activate Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii respectively, perform plate streaking and culture in an incubator at 30 °C for 48 h, pick a loop of the cultured strain into LB liquid medium, place it in a shaker at 30 °C and 200 r / min and shake and culture for 36 h to obtain three kinds of seed solutions. Inoculate the seed solutions of the three strains into 200 mL of TSB liquid medium at an inoculation amount of 2% respectively, and shake and culture at 30 °C and 200 r / min for 72 h to obtain fermentation broth; Mix the three fermentation broths according to a volume ratio of 1:1:1 to obtain the microbial inoculant.

[0137] The effective viable count of the microbial inoculant ≥ 4.0×10 9 CFU / g.

[0138] The preparation method of the above-mentioned environment-friendly biological organic fertilizer for improving acidified soil includes the following steps:

[0139] Step 1, prepare composite gel materials respectively;

[0140] Step 2, prepare a microbial inoculant;

[0141] Step 3, mix the prepared composite gel materials and the microbial inoculant evenly, culture at 30 °C for 24 h, then vacuum freeze-dry and grind into powder to obtain a mixed powder;

[0142] Step 4, mix the remaining raw materials and the mixed powder evenly and regranulate and dry at low temperature to obtain.

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

[0144] Comparative Example 3

[0145] An environment-friendly biological 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 livestock and poultry 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, 5 parts of sodium carboxymethylcellulose; The microbial inoculant is made by mixing Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii according to a volume ratio of 1:1:1.

[0146] The composite gel material is prepared by the following method:

[0147] a. Add 5 g of oyster shell modified biochar to 100 ml of 2 wt% carboxymethyl cellulose aqueous solution and stir well. Then, slowly add 100 ml of 4 wt% sodium alginate aqueous solution under stirring, and continue stirring for 30 - 60 min 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), and prepare a glucono - δ - lactone solution with a concentration of 1% (w / v). Mix the glucono - δ - lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B.

[0149] c. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:1, stir and cross - link at room temperature for 6 hours, then pour the cross - linked gel mixture into a specific mold to make it take shape. After standing at room temperature for 24 hours, vacuum freeze - dry and crush to obtain the composite gel material.

[0150] The oyster shell modified biochar is prepared by the following method:

[0151] 1) Using the brewed tea residues and tea production by - products as raw materials, dry at 100 °C, crush and pass through a 100 - mesh sieve to obtain waste tea powder.

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

[0153] 3) Transfer the above - mentioned pretreated waste tea powder into a muffle furnace, under anaerobic conditions, calcine at 550 °C for 2 h, then wash the product with acid until neutral, dry and grind into powder to obtain biochar.

[0154] 4) Wash and dry the oyster shells and crush them into small pieces, then transfer them into a muffle furnace and calcine at 500 °C for 2 h to obtain oyster shell powder.

[0155] 5) Mix the obtained biochar and oyster shell powder evenly according to a mass ratio of 3:1, then add deionized water according to a solid - liquid ratio of 1 g:30 ml, stir magnetically at room temperature for 6 - 8 h, then heat the mixed solution to 160 - 180 °C and react for 10 - 12 h, and then cool to room temperature, filter and dry to obtain the oyster shell modified biochar.

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

[0157] The composite microbial agent is prepared by the following method: Bacillus pseudofirmus, Pseudomonas guineensis and Azotobacter beijerinckii are thawed and activated respectively, and a plate is streaked and then cultured in a 30°C incubator for 48 hours, a loop of the cultured strain is taken into an LB liquid culture medium, and the culture is placed in a shaking incubator at 30°C and 200 r / min for 36 hours to obtain three seed liquids, and the seed liquids of the three strains are inoculated into 200 mL of TSB liquid culture medium at an inoculation amount of 2% respectively, and the culture is shaken at 30°C and 200 r / min for 72 hours to obtain fermentation liquid; and the three fermentation liquids 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 9 CFU / g.

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

[0160] Step 1, preparing composite gel material and waste tea biochar respectively;

[0161] Step 2, preparing a microbial agent;

[0162] Step 3, the prepared composite gel material, waste tea biochar and microbial agent are evenly mixed, cultured at 30° C. for 24 hours, vacuum freeze-dried and ground into powder to obtain a mixed powder;

[0163] Step 4, the remaining raw materials are mixed with the mixed powder evenly, and re-granulated and low-temperature dried to obtain.

[0164] This comparative example 2 is basically the same as example 3, except that the waste tea biochar is not modified.

[0165] Comparative Example 4

[0166] The invention discloses an environment-friendly biological organic fertilizer for improving acidified soil. The biological fertilizer is prepared from the following raw materials in parts by weight: 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 prepared by mixing Bacillus pseudofirmus, Pseudomonas glutinosa and nitrogen-fixing bacteria in a volume ratio of 1:1:1.

[0167] The composite microbial inoculant is prepared by the following method: Bacillus pseudofirmus, Pseudomonas gunnii, and Azotobacter beijerinckii are thawed and activated respectively. After streaking on a plate, they are cultured in an incubator at 30°C for 48 h. One loop of the cultured strain is taken and placed in an LB liquid medium, and then cultured in a shaker at 30°C and 200 r / min for 36 h to obtain three kinds of seed solutions. The seed solutions of the three strains are inoculated into 200 mL of TSB liquid medium at an inoculation amount of 2% respectively, and cultured in a shaker at 30°C and 200 r / min for 72 h to obtain fermentation broths; the three fermentation broths are mixed according to a volume ratio of 1:1:1 to obtain the microbial inoculant.

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

[0169] The preparation method of the above-mentioned environment-friendly biological organic fertilizer for improving acidified soil includes the following steps:

[0170] Step 1, prepare the microbial inoculant;

[0171] Step 2, uniformly mix the prepared microbial inoculant with the remaining other raw materials, and regranulate and dry at low temperature to obtain the product.

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

[0173] Comparative Example 5

[0174] This comparative example is basically the same as Example 3, and the only difference is that: the microbial inoculant does not contain Azotobacter beijerinckii.

[0175] Comparative Example 6

[0176] This comparative example is basically the same as Example 3, and the only difference is that: the microbial inoculant does not contain Pseudomonas gunnii.

[0177] Comparative Example 7

[0178] This comparative example is basically the same as Example 3, and the only difference is that: the microbial inoculant does not contain Bacillus pseudofirmus.

[0179] Field planting application test

[0180] The environment-friendly biological organic fertilizers for improving acidified soil prepared in Examples 1-3 and Comparative Examples 1-7 were used for a field potato planting test. A potato planting base in Chongfang Town, Tancheng County, Linyi City was selected for the test, and the potato variety was Zhongshu No. 2. A total of 11 treatments were set up in the test, namely the treatment groups of Examples 1-3, Comparative Examples 1-7, and the conventional fertilizer control group (N:P2O5:K2O = 15:15:15). The area of each plot was 50 m 2Planting in two rows on wide ridges, the ridge width is 40 cm, the ridge height is 25 cm, and the planting density is 55,000 plants / hm 2 , the dosage of each treatment group is 200 kg / mu except for the conventional fertilizer control group, and the dosage of the conventional control group is 50 kg / mu. All are incorporated into the soil as base fertilizers before potato planting. Other conventional field management is the same. The basic physical and chemical properties of the experimental field soil are shown in Table 1:

[0181] Table 1 Soil physical and chemical properties

[0182] Measure the yield at potato harvest. Measure the crude protein, reducing sugar, Vc content,

[0183]

[0184] starch content, and nitrate content within 14 days after harvest. The specific test results are shown in Table 2.

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

[0186]

[0187]

[0188] It can be seen from the data in Table 2 above that after using the environment-friendly bio-organic fertilizer for improving acidified soil prepared in the embodiment of the present invention, the indicators such as the yield, crude protein content, reducing sugar content, Vc content, and starch content of potatoes are significantly better than those of Comparative Examples 1-7, and compared with the conventional control, the yield increase rate is more than 20.0%. This is because the environment-friendly bio-organic fertilizer for improving acidified soil prepared in 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, which helps to promote the growth and development of plants and improve the yield and quality of crops.

[0189] After potato harvest, collect surface soil (0-30 cm) samples, and collect soil samples according to the S-shaped sampling method for each treatment group. When taking soil, the soil drill is inserted to a depth of 30 cm at one time. Each treatment group is sampled 3 times repeatedly, and the 3 repeated samples of the same treatment group are mixed into one sample, removing visible impurities such as gravel and plant roots, and bringing them back to the laboratory to measure the basic physical and chemical properties of the soil, soil enzyme activity, and soil microbial biomass. The results are shown in Tables 3-4 below. Among them, the test method for soil enzyme activity is: using the phenol sodium-sodium hypochlorite colorimetric method to measure soil urease activity, using the potassium permanganate titration method to measure catalase activity, using the 3,5-dinitrosalicylic acid colorimetric method to measure sucrase activity, using the phenyl phosphate disodium colorimetric method to measure phosphatase activity, and using the fumigation extraction-volumetric analysis method to measure microbial biomass.

[0190] Table 3 Soil physical and chemical properties of different treatment groups

[0191]

[0192]

[0193] As can be seen from the data in Table 3 above, after using the environment-friendly bio-organic fertilizer for improving acidified soil prepared in Examples 1-3 of the present invention, the soil pH has been significantly increased, the exchangeable aluminum content has decreased, the soil microbial biomass and organic matter content have both increased significantly, the soil acidification situation has been significantly modified, and the soil microbial content has increased significantly. This is because the composite gel material used in the present invention is combined with the modified waste tea biochar for acidified soil improvement, and the two work synergistically to achieve the organic combination of rapid and long-term effects in acidified soil improvement, which has stability and persistence in the improvement of acidified soil and good improvement effects.

[0194] Table 4 Soil Enzyme Activities of Different Treatment Groups

[0195]

[0196]

[0197] As can be seen from the data in Table 4 above, after using the environment-friendly bio-organic fertilizer for improving acidified soil prepared in Examples 1-3 of the present invention, the soil enzyme activities have been significantly improved. This is because after being applied to the soil, various components work synergistically, and a large number of beneficial microorganisms multiply to form a dominant flora, restoring soil microbial diversity, enhancing the self-regulating ability of the soil ecosystem, accelerating soil nutrient cycling, improving soil structure, and alleviating the hardening problem caused by acidification. The comprehensive manifestation is to improve soil enzyme activities and increase the number of soil microorganisms. Reducing or changing any one of the components of the bio-organic fertilizer of the present invention will result in the disappearance or weakening of the corresponding effects.

[0198] It should be noted that the above-mentioned embodiments are only some of the embodiments of the preferred ways to implement the present invention, rather than all embodiments. Obviously, based on the above-mentioned embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Claims

1. An environment-friendly biological organic fertilizer for improving acidified soil, characterized in that, It is made from the following raw materials in parts by weight: 10-20 parts of composite gel material, 80-100 parts of decomposed livestock and poultry manure, 10-20 parts of microbial inoculum, 30-50 parts of modified waste tea biochar, 10-15 parts of urea, 5-10 parts of humic acid, 1-5 parts of superphosphate, and 1-5 parts of sodium carboxymethylcellulose; the microbial inoculum is prepared by mixing Bacillus pseudofirmus, Pseudomonas gunungensis, and Azotobacter beijerinckii in a volume ratio of 1:1:1; the strain number of Bacillus pseudofirmus is CGMCC No. 1.7924, purchased from the China General Microbiological Culture Collection Center, and the preservation date is July 1, 2008; the strain number of Pseudomonas gunungensis is CGMCC No. 1.15627, purchased from the China General Microbiological Culture Collection Center, and the preservation date is February 25, 2015; the strain number of Azotobacter beijerinckii is CGMCC No. 1.5802, purchased from the China General Microbiological Culture Collection Center, and the preservation date is June 27, 2005.

2. The environment-friendly biological organic fertilizer for improving acidified soil according to claim 1, characterized in that, The composite gel material is prepared by the following method: a. Add 5 g of oyster shell modified biochar to 100 ml of 2 wt% sodium carboxymethylcellulose aqueous solution and stir well. Then, slowly add 100 ml of 4 wt% sodium alginate aqueous solution under stirring, and continue stirring for 30-60 min to form a uniform mixed solution A; b. Dissolve CaCO3 in deionized water to prepare a suspension with a concentration of 3% (w / v), and prepare a glucono-δ-lactone solution with a concentration of 1% (w / v). Mix the glucono-δ-lactone solution and the CaCO3 suspension in a volume ratio of 1:1 to obtain a mixed solution B; c. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:1, stir and crosslink at room temperature for 6 hours, then pour the crosslinked gel mixture into a specific mold to form it. After standing at room temperature for 24 hours, vacuum freeze-dry and pulverize to obtain the composite gel material.

3. The environment-friendly biological organic fertilizer for improving acidified soil according to claim 2, characterized in that The oyster shell modified biochar is prepared by the following method: 1) Using the brewed tea residues and tea production by-products as raw materials, dry at 100 °C and then pulverize and pass through a 100-mesh sieve to obtain waste tea powder; 2) Take 10 g of waste tea powder and add it to 100 ml of 1 mol / L KOH solution, stir magnetically for 24 h, and then dry to obtain pretreated waste tea powder; 3) Transfer the above pretreated waste tea powder into a muffle furnace, under anaerobic conditions, calcine at 550 °C for 2 h, then wash the product with acid until neutral, dry and grind it into powder to obtain biochar; 4) Wash the oyster shells, dry them and crush them into small pieces, then transfer them into a muffle furnace and calcine at 500 °C for 2 h to obtain oyster shell powder; 5) Mix the obtained biochar and oyster shell powder evenly at a mass ratio of 3:1 to obtain a mixture, then add deionized water at a solid-liquid ratio of 1 g:30 ml, magnetically stir and react at room temperature for 6 - 8 h, then heat the mixed solution to 160 - 180 °C and react for 10 - 12 h, and cool to room temperature, filter and dry to obtain oyster shell modified biochar.

4. The environment-friendly biological organic fertilizer for improving acidified soil according to claim 1, wherein the modified waste tea biochar is prepared by the following method: A1: Take waste tea such as brewed tea residues and tea production by-products, dry them and transfer them to a muffle furnace, heat up to 550 °C under nitrogen protection and calcine for 2 h to obtain waste tea biochar; A2: Immerse the waste tea biochar in 1 mol / L NaOH solution according to the solid-liquid ratio, ultrasonically treat 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 glutamic acid and ZnCl2 respectively and dissolve them in deionized water, ultrasonically disperse for 5 - 10 min to obtain a mixed solution, add the alkali-treated biochar obtained in A2 to the mixed solution, magnetically stir for 5 - 6 h, separate the solid and liquid, and dry the solid to obtain modified waste tea biochar.

5. The environment-friendly biological organic fertilizer for improving acidified soil according to claim 4, characterized in that, The solid-liquid ratio in A2 is 1 g:10 ml.

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

7. The environment-friendly biological organic fertilizer for improving acidified soil according to claim 1, wherein, The composite microbial inoculant is prepared by the following method: Thaw and activate Bacillus pseudofirmus, Pseudomonas guangdongensis, and Azotobacter beijerinckii respectively, perform plate streaking and culture in an incubator at 30 °C for 48 h, take a loop of the cultured strain and place it in an LB liquid medium, place it in a shaker at 30 °C and 200 r / min and shake and culture for 36 h to obtain three seed solutions, inoculate the seed solutions of the three strains into 200 mL of TSB liquid medium at an inoculation amount of 2% respectively, culture at 30 °C and 200 r / min for 72 h to obtain fermentation broths; mix the three fermentation broths according to a volume ratio of 1:1:1 to obtain the microbial inoculant.

8. The environment-friendly biological organic fertilizer for improving acidified soil according to claim 7, characterized in that, The viable count of the microbial inoculum is ≥ 4.0×10 9 CFU / g.

9. A method for preparing the environment-friendly biological organic fertilizer for improving acidified soil according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1, prepare the composite gel material and the modified waste tea biochar respectively; Step 2, prepare the microbial inoculant; Step 3, mix the prepared composite gel material, modified waste tea biochar and microbial inoculant evenly, culture at 30 °C for 24 h, then vacuum freeze-dry and grind into powder to obtain a mixed powder; Step 4, mix the remaining raw materials and the mixed powder evenly and re-pelletize and dry at low temperature to obtain the product.

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