Multi-element soil fertility improvement biological modifier and preparation method thereof

Abstract

The invention discloses a multi-element soil fertility improvement biological modifier and a preparation method thereof, and belongs to the technical field of soil fertility improvement. The modifier is prepared from modified straw aerogel, a strontium titanate loaded lignin compound, lanthanide modified potassium feldspar powder, alginic acid oligosaccharide composite gamma-aminobutyric acid, carbon nitride quantum dots, bacterial cellulose nanofibers and polyaniline nanotubes according to the mass ratio of (18-22): (15-17): (13-15): (7-10): (10-13): (3-5): (7-10): (10-13): (5-8). The composite microbial inoculant is composed of a nano zero-valent iron-montmorillonite compound and a nitrogen fixation-phosphate solubilizing composite microbial inoculant. The modified straw aerogel and the bacterial cellulose nanofibers are interwoven to form a three-dimensional network framework, a habitat is provided for soil microorganisms, the water and fertilizer retention capacity of soil is enhanced, and meanwhile, the network structure promotes transmission of nutrients and water in the soil and improves the nutrient utilization efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of soil fertilization, and particularly relates to a multi-element soil fertilization biological improver and a preparation method thereof. Background Art

[0002] As the foundation of human survival and development, the quality of land is of vital importance.

[0003] Maintaining soil quality, improving soil acidity and alkalinity, and reducing soil pollution have become a focus of widespread public concern. The use of soil conditioners has become a key means of alleviating agricultural production crises and improving soil conditions. Soil conditioners, also known as soil conditioners, are primarily used to improve the physical, chemical, and biological properties of soil to create a more suitable environment for plant growth. Their core function is not to directly provide nutrients to plants, but rather to promote the aggregation of small, cohesive soil particles into larger, stable aggregates that retain water. In practical application, soil conditioners demonstrate multiple benefits. They can improve soil structure, promote solid particle formation, enhance water retention and air permeability, and reduce soil erosion; they help conserve irrigation water and create optimal moisture conditions for plant growth; they can also regulate soil pH and enhance soil buffering capacity, providing a more suitable acid-base environment for plant growth, reducing the risk of nutrient loss, minimizing the incidence of pests and diseases, and reducing pesticide application, thereby lowering post-planting maintenance costs.

[0004] However, current soil conditioners generally suffer from a single ingredient. While improving soil structure, they fail to simultaneously boost soil fertility. This can lead to the situation where, even with the use of soil conditioners, large amounts of chemical fertilizers are still needed to meet crop nutrient needs in actual agricultural production. This approach fails to fundamentally address the issue of soil structural changes and instead creates a dependence on chemical fertilizers. This creates a vicious cycle that further damages the soil ecosystem, reduces soil quality, and impacts the sustainable development of agriculture. Furthermore, some current soil conditioners are synthetic high-molecular compounds that are difficult to degrade in the soil, causing soil pollution and posing a potential threat to the long-term stability of the soil ecosystem. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a multi-element soil fertilization biological amendment and a preparation method thereof, so as to solve the problem that the current soil amendments are not effective.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The invention provides a multi-element soil fertilization biological improver. The improver consists of modified straw aerogel, strontium titanate-loaded lignin complex, potassium feldspar powder, alginate oligosaccharide complexed with gamma-aminobutyric acid, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite complex, and composite bacterial agent in a mass ratio of 18-22:15-17:13-15:7-10:10-13:3-5:7-10:10-13:5-8.

[0008] Furthermore, the composite bacterial agent is a nitrogen-fixing and phosphate-solubilizing composite bacterial agent, which is composed of a composite arbuscular mycorrhizal fungus of jelly-like Bacillus, a composite Trichoderma of nitrogen-fixing bacteria, and a composite phosphate-solubilizing bacteria of Streptomyces griseus; and the potassium feldspar powder is potassium feldspar powder modified with lanthanide elements.

[0009] Furthermore, a method for preparing a multi-element soil fertilization biological improver comprises the following steps:

[0010] S1. Crush the straw into small pieces, soak them in sodium hydroxide solution, and then wash them with water until neutral; then continue soaking them in hydrochloric acid solution, wash them with water until neutral, and then dry them;

[0011] S2, crushing the straw treated in step S1, mixing it with the polyvinyl alcohol solution, adding glutaraldehyde crosslinking agent after stirring evenly, pouring the reaction solution into a mold for freeze drying after the reaction, and crushing the modified straw aerogel for later use;

[0012] S3, tetrabutyl titanate, anhydrous ethanol, and glacial acetic acid were mixed in a volume ratio, stirred evenly, and then deionized water was added dropwise and stirred continuously to obtain a transparent strontium titanate sol;

[0013] S4, dissolving lignin in a sodium hydroxide solution to obtain a lignin solution, then dripping strontium titanate sol into the lignin solution for reaction, and then centrifuging, washing, drying, and calcining to obtain a strontium titanate-loaded lignin composite;

[0014] S5, crushing the potassium feldspar and soaking it in a hydrochloric acid solution to remove impurities, then washing it with water until it is neutral and drying it, and then mixing it with a cerium nitrate solution and stirring it to react. The reaction product is centrifuged, washed with water, and dried to obtain lanthanide-modified potassium feldspar powder;

[0015] S6. Mix alginate oligosaccharide and γ-aminobutyric acid according to a mass ratio, dissolve in deionized water, and prepare a mixed solution;

[0016] S7, calcining urea, cooling and grinding into powder, dispersing the powder in deionized water, ultrasonically treating and centrifuging, taking the supernatant for dialysis and freeze-drying to obtain carbon nitride quantum dots;

[0017] S8, inoculating Acetobacter xylinum in a culture medium containing glucose, yeast extract, and peptone, culturing at room temperature, collecting the bacterial cellulose film formed on the surface of the culture medium, repeatedly washing with deionized water to remove impurities, then treating with sodium hydroxide solution to remove residual bacteria, washing with water until neutral, freeze-drying, and then crushing to obtain bacterial cellulose nanofibers;

[0018] S9, dissolving aniline monomer and ammonium persulfate in a hydrochloric acid solution in a molar ratio, adding the ammonium persulfate solution dropwise to the aniline solution at 0-5° C. for reaction, centrifuging the reaction product, washing it with water, soaking it in ammonia water for doping, and then washing it with water and drying it to obtain polyaniline nanotubes;

[0019] S10, dispersing montmorillonite in deionized water to form a suspension, adding ferrous sulfate solution to the suspension and stirring evenly, and adding sodium borohydride solution dropwise under nitrogen protection to react, and the reaction product is centrifuged, washed with water, and dried to obtain a nano-zero-valent iron-montmorillonite composite;

[0020] S11. Inoculate the jelly-like Paenibacillus, arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, Trichoderma, Streptomyces griseus, and phosphate-solubilizing bacteria into the liquid culture medium respectively, and set the parameters so that the final bacterial population density reaches 10 12 CFU / g; the cultured bacteria were mixed with arbuscular mycorrhizal fungi, nitrogen-fixing bacteria with Trichoderma, and gray chain with phosphate-solubilizing bacteria in proportion, and then the mixed bacteria were made into powder and mixed for later use;

[0021] S12. Place the modified straw aerogel, strontium titanate loaded lignin complex, lanthanide element modified potassium feldspar powder, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite complex, and nitrogen-fixing-phosphorus-dissolving composite bacterial agent into a high-speed mixer, and add a mixture of alginate oligosaccharide and γ-aminobutyric acid at room temperature and stir at 800-1000 rpm / min for 30-40 minutes to fully and evenly mix the raw materials. Finally, encapsulate with chitosan-sodium alginate microcapsules to obtain a new soil conditioner.

[0022] Furthermore, in step S1, the length of the straw is 2-5 cm, the mass fraction of sodium hydroxide is 1-2%, the soaking temperature in the sodium hydroxide solution is 80-90° C., and the soaking time is 2-3 hours; the mass fraction of the hydrochloric acid solution is 1-2%, the soaking temperature in the hydrochloric acid solution is 60-70° C., and the soaking time is 1-2 hours;

[0023] In step S2, the mass fraction of the polyvinyl alcohol solution is 5-10%, and the mass ratio of the straw powder to the polyvinyl alcohol solution is 1:3-5; the mass fraction of the glutaraldehyde cross-linking agent is 2-5%, the reaction temperature after adding the glutaraldehyde cross-linking agent is 50-60°C, and the reaction time is 2-3 hours; the reaction conditions of the reaction liquid in the mold are first frozen to minus 20-minus 30°C, maintained for 12-24 hours, and then freeze-dried and continued to freeze for 48-72 hours.

[0024] Furthermore, in step S3, the volume ratio of tetrabutyl titanate, anhydrous ethanol, and glacial acetic acid is 1:5:1, and the molar ratio of deionized water to tetrabutyl titanate is 1:4-6;

[0025] In step S4, the mass fraction of the sodium hydroxide solution is 10-20%, the mass fraction of the lignin solution is 5-10%, the reaction temperature after the strontium titanate sol is added dropwise is 60-70°C, the reaction time is 3-4h; the calcination temperature is 500-600°C and the time is 2-3h.

[0026] Furthermore, in step S5, the mass fraction of the hydrochloric acid solution is 10-15%, the soaking temperature is 90-100° C., and the soaking time is 3-4 hours; the molar ratio of the potassium feldspar powder to the cerium nitrate solution is 1:10-15, the reaction temperature is 80-90° C., and the reaction time is 4-5 hours;

[0027] In step S6, the mass ratio of alginate oligosaccharide to γ-aminobutyric acid is 3:2, and the mass fraction of the obtained mixed solution is 10-20%.

[0028] Furthermore, in step S7, the calcination temperature of urea is 500-600° C. and the time is 2-3 hours;

[0029] In step S8, the mass ratio of glucose, yeast extract and peptone is 1:1:1, and the mass fraction of the sodium hydroxide solution used to remove residual bacteria is 0.1-0.2%.

[0030] Furthermore, in step S9, the molar ratio of the aniline monomer to ammonium persulfate is 1:1-1.5, the mass fraction of the hydrochloric acid solution is 1 mol / L; the mass fraction of the ammonia water is 10-20%, and the soaking time is 1-2 hours.

[0031] Furthermore, in step S10, the mass fraction of the suspension is 2-5%, the mass ratio of the ferrous sulfate solution to the montmorillonite is 1:10-15, and the mass fraction of the sodium borohydride solution is 10-20%.

[0032] The beneficial effects of the present invention are:

[0033] 1. In the present invention, the modified straw aerogel and bacterial cellulose nanofibers are interwoven to form a three-dimensional network skeleton, which provides a habitat for soil microorganisms and enhances the soil's ability to retain water and fertilizer. At the same time, the network structure promotes the transmission of nutrients and water in the soil and improves nutrient utilization efficiency.

[0034] 2. In the present invention, in the strontium titanate-loaded lignin composite, the electron-hole pairs generated by strontium titanate photocatalysis work synergistically with the active oxygen species generated by carbon nitride quantum dots to accelerate the decomposition of refractory organic matter in the soil. Lignin interacts with bacterial cellulose nanofibers and soil particles, continuously improving the soil aggregate structure.

[0035] 3. In the present invention, during the release of potassium from lanthanide-modified potassium feldspar powder, lanthanides and alginate oligosaccharides complexed with γ-aminobutyric acid act synergistically on plant roots, promoting plant absorption of potassium and other nutrients. Lanthanides can also regulate soil microbial communities and synergistically optimize soil ecology with microorganisms in modified straw aerogels.

[0036] 4. In the present invention, the prepared alginate oligosaccharide-complexed γ-complexed aminobutyric acid solution as a mixed solution between substances can stimulate plant growth, increase root secretions, and the secretions interact with carbon nitride quantum dots, polyaniline nanotubes, etc., promote nutrient activation and transmission, form a virtuous cycle, and continuously stimulate soil vitality.

[0037] 5. In the present invention, polyaniline nanotubes regulate the surface charge of soil particles, promote ion exchange, and accelerate the migration of nutrients to plant roots. They work synergistically with nano zero-valent iron-montmorillonite complexes to enhance the ability to remove and repair pollutants in the soil.

[0038] 6. In the present invention, nitrogen-fixing bacteria, phosphate-solubilizing bacteria and potassium-solubilizing bacteria cooperate with each other in the soil to convert nitrogen in the air, phosphorus and potassium in the soil into forms that can be directly absorbed and utilized by plants, thereby increasing the nitrogen, phosphorus and potassium content in the soil to meet the needs of plant growth.

[0039] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to make the purpose, technical solutions and beneficial effects of the invention clearer, the present invention is described with the following drawings:

[0041] Figure 1 Flow chart of the preparation of the improver of the present invention. DETAILED DESCRIPTION

[0042] like Figure 1 As shown, the present invention provides a multi-element soil fertilization biological improver and a preparation method thereof.

[0043] In the present invention, the limiting value before the solution is the mass fraction.

[0044] Example 1

[0045] S1. Crush corn stalks into 3 cm segments, soak them in 1.5% sodium hydroxide solution at 85°C for 2.5 hours to remove impurities such as pectin and hemicellulose, wash them with water until neutral, soak them in 1.5% hydrochloric acid solution at 65°C for 1.5 hours to remove minerals, wash them again with water until neutral, and then dry them;

[0046] S2, crushing the dried straw into 150 mesh, mixing it with 7.5% polyvinyl alcohol solution at a mass ratio of 1:4, stirring evenly, adding 3.5% glutaraldehyde crosslinking agent, reacting at 55°C for 2.5 hours, and then pouring the reaction solution into a mold, freezing it to -25°C for 18 hours, and continuing freeze-drying for 60 hours, and then crushing it to obtain modified straw aerogel;

[0047] S3. Tetrabutyl titanate, anhydrous ethanol, and glacial acetic acid were mixed in a volume ratio of 1:5:1, stirred evenly, and deionized water (water to tetrabutyl titanate ratio of 5:1) was added dropwise. Stirring was continued for 2.5 hours to obtain a transparent strontium titanate sol.

[0048] S4, dissolving lignin in 15% sodium hydroxide solution to prepare a 7.5% lignin solution, and then slowly dripping strontium titanate sol into the lignin solution while stirring, reacting at 65°C for 3.5 hours, centrifuging the reaction product, washing with water, drying, and then calcining at 550°C for 2.5 hours to obtain a strontium titanate-loaded lignin composite;

[0049] S5, crushing the potassium feldspar into 250 mesh, soaking it in 12% hydrochloric acid solution at 95° C. for 3 hours, removing impurities, washing it with water until it is neutral, and then drying it, mixing the dried potassium feldspar powder with a cerium nitrate solution (wherein the molar ratio of cerium to potassium is 1:12.5), stirring and reacting it at 85° C. for 4.5 hours, and then centrifuging the reaction product, washing it with water, and drying it to obtain lanthanide-modified potassium feldspar powder;

[0050] S6. Weigh alginate oligosaccharide and γ-aminobutyric acid in a mass ratio of 3:2, dissolve them in deionized water to prepare a mixed solution with a mass fraction of 15%, and obtain an alginate oligosaccharide complexed with γ-aminobutyric acid solution;

[0051] S7, calcining urea at 550°C for 2.5 hours, grinding it into powder after cooling, dissolving and dispersing it in deionized water, ultrasonically treating it for 2.5 hours, centrifuging it, taking the supernatant and dialyzing it for 3 days, and freeze-drying it to obtain carbon nitride quantum dots;

[0052] S8. Inoculate Acetobacter xylinum in a culture medium containing glucose, yeast extract, and peptone (the mass ratio of glucose, yeast extract, and peptone is 1:1:1), and culture at 28°C for 6 days. Then, collect the bacterial cellulose film formed on the surface of the culture medium, wash it repeatedly with deionized water to remove impurities, and then treat it with 0.15% sodium hydroxide solution at 85°C for 1.5 hours to remove residual bacteria. After washing with water until neutral, freeze-dry and crush to obtain bacterial cellulose nanofibers;

[0053] S9, dissolving aniline monomer and ammonium persulfate in a 1 mol / L hydrochloric acid solution at a molar ratio of 1:1.25, and then slowly dropping the ammonium persulfate solution into the aniline solution at 2.5° C. with stirring. After the addition is complete, the reaction is allowed to react for 2.5 hours. The reaction product is centrifuged, washed with water, and soaked in 15% ammonia water for 1.5 hours for doping, and then washed with water and dried to obtain polyaniline nanotubes;

[0054] S10, dispersing montmorillonite in deionized water to form a suspension with a mass fraction of 3.5%, adding ferrous sulfate solution (wherein the mass ratio of iron to montmorillonite is 1:12.5) to the suspension, stirring evenly, and then slowly adding 15% sodium borohydride solution (wherein the molar ratio of sodium borohydride to iron is 2.5:1) dropwise under nitrogen protection, stirring while dropping and reacting for 1.5 hours. The reaction product is centrifuged, washed with water, and dried to obtain a nano-zero-valent iron-montmorillonite composite;

[0055] S11. Inoculate Paenibacillus jelly, arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, Trichoderma, Streptomyces griseus, and phosphate-solubilizing bacteria into liquid culture medium, respectively, and culture at 30°C with a shaker speed of 175 pm / min. At the same time, switch between anoxic and oxygen-rich conditions, and gradually increase the salt concentration to 8% for stress tolerance screening, so that the final bacterial population density reaches 10 12 CFU / g; the cultured bacteria were mixed with arbuscular mycorrhizal fungi, nitrogen-fixing bacteria with Trichoderma, and gray chain with phosphate-solubilizing bacteria in a mass ratio of 1:1, and the mixed bacteria were powdered and mixed for later use;

[0056] S12. Modified straw aerogel, strontium titanate loaded lignin complex, lanthanide modified potassium feldspar powder, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, and nano zero-valent iron-montmorillonite complex are weighed in a mass ratio of 20:15:15:10:5:10:10:5, and the mixture is stirred first. Then, a mixture of alginate oligosaccharides and γ-aminobutyric acid with a mass ratio of 10 is added and continued to be stirred. After stirring evenly, the mixture is put into a high-speed mixer and stirred at 900 rpm / min for 35 minutes at room temperature. The raw materials are fully and evenly mixed and encapsulated with chitosan-sodium alginate microcapsules to obtain a new soil conditioner. The weight of each soil conditioner is 20 g.

[0057] Step S1-11 can be prepared simultaneously or after the material that takes longer to prepare is completed, depending on the preparation process.

[0058] Example 2

[0059] The difference between Example 2 and Example 1 is that in step S12, the mass ratio of the modified straw aerogel, strontium titanate-loaded lignin composite, lanthanide-modified potassium feldspar powder, alginate oligosaccharide complexed with γ-aminobutyric acid, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite composite, and nitrogen-fixing-phosphorus-solubilizing composite bacterial agent is 18:17:14:10:13:5:7:13:8, and the rest is the same as Example 1.

[0060] Example 3

[0061] The difference between Example 3 and Example 1 is that in step S12, the mass ratio of the modified straw aerogel, strontium titanate-loaded lignin composite, lanthanide-modified potassium feldspar powder, alginate oligosaccharide complexed with γ-aminobutyric acid, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite composite, and nitrogen-fixing-phosphorus-solubilizing composite bacterial agent is 22:15:13:13:10:4:19:12:6.5, and the rest is the same as Example 1.

[0062] The raw materials and proportions used in Examples 1 to 3 are all within the scope of protection of the present invention. The resulting improvers can effectively stimulate soil vitality and are more effective, efficient, and beneficial than conventional improvers.

[0063] In order to verify the superiority of the present invention, comparative examples 1 and 2 are set up here.

[0064] Comparative Example 1

[0065] The difference between Comparative Example 1 and Example 1 is that in step S12, the mass ratio of the modified straw aerogel, strontium titanate-loaded lignin composite, lanthanide-modified potassium feldspar powder, alginate oligosaccharide complexed with γ-aminobutyric acid, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite composite, and nitrogen-fixing-phosphorus-solubilizing composite bacterial agent is 10:10:10:10:10:10:10:10:10:10, and the rest is the same as in Example 1.

[0066] Comparative Example 2

[0067] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 uses a conventional improver.

[0068] The improvers of Examples 1 to 3 and Comparative Examples 1 to 2 were applied to the soil respectively to perform three types of repair:

[0069] 1. Deep restoration mode: Mix with the cultivated soil at a ratio of 1:50 and then till into the soil;

[0070] 2. Targeted repair mode: Prepare 5% water suspension and apply it through drip irrigation system;

[0071] 3. Light activation treatment: ensure that the average daily light exposure is ≥ 4 hours within 72 hours after application to trigger biomass conversion.

[0072] The soil values ​​were measured 3 months and 6 months after application, as shown in Table 1:

[0073]

[0074]

[0075] As can be seen from the table above, after applying the improvers prepared by Examples 1-3 of the present invention to soil, various aspects of the soil condition were significantly improved, including significantly increased soil fertility, significantly increased microbial activity, significantly improved soil pollutants, improved soil structure, and accelerated plant growth. However, Comparative Example 1, which does not employ the present invention, achieved similar soil improvement effects to the improver prepared by conventional methods, even though the same substances were used, and the soil improvement effect was not significant.

[0076] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A multi-element soil fertilization bio-modifier, characterized by: The improver consists of modified straw aerogel, strontium titanate-loaded lignin complex, potassium feldspar powder, alginate oligosaccharide-complexed γ-aminobutyric acid, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite complex, and composite bacterial agent in a mass ratio of 18-22:15-17:13-15:7-10:10-13:3-5:7-10:10-13:5-8.

2. The multi-element soil fertilization bio-modifier according to claim 1, characterized in that: The composite bacterial agent is a nitrogen-fixing and phosphate-dissolving composite bacterial agent, which is composed of jelly-like Bacillus complex arbuscular mycorrhizal fungi, nitrogen-fixing bacteria complex Trichoderma, and Streptomyces griseus complex phosphate-dissolving bacteria; the potassium feldspar powder is lanthanide-modified potassium feldspar powder.

3. A method for preparing a multi-element soil fertilization biomodifier according to any one of claims 1-2, characterized in that: The following steps are included: S1. Crush the straw into small pieces, soak them in sodium hydroxide solution, and then wash them with water until neutral; then continue soaking them in hydrochloric acid solution, wash them with water until neutral, and then dry them; S2, crushing the straw treated in step S1, mixing it with the polyvinyl alcohol solution, stirring evenly, adding glutaraldehyde crosslinking agent, pouring the reaction solution into a mold for freeze-drying, and then crushing the modified straw aerogel for later use; S3, tetrabutyl titanate, anhydrous ethanol, and glacial acetic acid were mixed in a volume ratio, stirred evenly, and then deionized water was added dropwise and stirred continuously to obtain a transparent strontium titanate sol; S4, dissolving lignin in a sodium hydroxide solution to obtain a lignin solution, then dripping strontium titanate sol into the lignin solution for reaction, and then centrifuging, washing, drying, and calcining to obtain a strontium titanate-loaded lignin composite; S5, crushing the potassium feldspar and soaking it in a hydrochloric acid solution to remove impurities, then washing it with water until it is neutral and drying it, and then mixing it with a cerium nitrate solution and stirring it to react. The reaction product is centrifuged, washed with water, and dried to obtain lanthanide-modified potassium feldspar powder; S6. Mix alginate oligosaccharide and γ-aminobutyric acid according to a mass ratio, dissolve in deionized water, and prepare a mixed solution; S7, calcining urea, cooling and grinding into powder, dispersing the powder in deionized water, ultrasonically treating and centrifuging, taking the supernatant for dialysis and freeze-drying to obtain carbon nitride quantum dots; S8, inoculating Acetobacter xylinum in a culture medium containing glucose, yeast extract, and peptone, culturing at room temperature, collecting the bacterial cellulose film formed on the surface of the culture medium, repeatedly washing with deionized water to remove impurities, then treating with sodium hydroxide solution to remove residual bacteria, washing with water until neutral, freeze-drying, and then crushing to obtain bacterial cellulose nanofibers; S9, dissolving aniline monomer and ammonium persulfate in a hydrochloric acid solution in a molar ratio, adding the ammonium persulfate solution dropwise to the aniline solution at 0-5° C. for reaction, centrifuging the reaction product, washing it with water, soaking it in ammonia water for doping, and then washing it with water and drying it to obtain polyaniline nanotubes; S10, dispersing montmorillonite in deionized water to form a suspension, adding ferrous sulfate solution to the suspension and stirring evenly, and adding sodium borohydride solution dropwise under nitrogen protection to react, and the reaction product is centrifuged, washed with water, and dried to obtain a nano-zero-valent iron-montmorillonite composite; S11. Inoculate the jelly-like Paenibacillus, arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, Trichoderma, Streptomyces griseus, and phosphate-solubilizing bacteria into the liquid culture medium respectively, and set the parameters so that the final bacterial population density reaches 10 12 CFU / g; the cultured bacteria were mixed with arbuscular mycorrhizal fungi, nitrogen-fixing bacteria with Trichoderma, and gray chain with phosphate-solubilizing bacteria in proportion, and then the mixed bacteria were made into powder and mixed for later use; S12. Place the modified straw aerogel, strontium titanate-loaded lignin complex, lanthanide-modified potassium feldspar powder, carbon nitride quantum dots, bacterial cellulose nanofibers, polyaniline nanotubes, nano zero-valent iron-montmorillonite complex, and nitrogen-fixing-phosphorus-solubilizing composite bacterial agent into a high-speed mixer, and add a mixture of alginate oligosaccharide and γ-aminobutyric acid. Stir and mix at room temperature at 800-1000 rpm / min for 30-40 minutes to ensure that all the raw materials are fully and evenly mixed. Finally, encapsulate the mixture with chitosan-sodium alginate microcapsules to obtain a new soil conditioner.

4. The method for preparing a multi-element soil fertilization biomodifier according to claim 3, characterized in that: In step S1, the length of the straw is 2-5 cm, the mass fraction of sodium hydroxide is 1-2%, the soaking temperature in the sodium hydroxide solution is 80-90° C., and the soaking time is 2-3 hours; the mass fraction of the hydrochloric acid solution is 1-2%, the soaking temperature in the hydrochloric acid solution is 60-70° C., and the soaking time is 1-2 hours; In step S2, the mass fraction of the polyvinyl alcohol solution is 5-10%, and the mass ratio of the straw powder to the polyvinyl alcohol solution is 1:3-5; the mass fraction of the glutaraldehyde cross-linking agent is 2-5%, the reaction temperature after adding the glutaraldehyde cross-linking agent is 50-60°C, and the reaction time is 2-3 hours; the reaction conditions of the reaction liquid in the mold are first frozen to minus 20-minus 30°C, maintained for 12-24 hours, and then freeze-dried and continued to freeze for 48-72 hours.

5. The method for preparing a multi-element soil fertilization bio-modifier according to claim 3, characterized in that: In step S3, the volume ratio of tetrabutyl titanate, anhydrous ethanol, and glacial acetic acid is 1:5:1, and the molar ratio of deionized water to tetrabutyl titanate is 1:4-6; In step S4, the mass fraction of the sodium hydroxide solution is 10-20%, the mass fraction of the lignin solution is 5-10%, the reaction temperature after the strontium titanate sol is added dropwise is 60-70°C, the reaction time is 3-4h; the calcination temperature is 500-600°C and the time is 2-3h.

6. The method for preparing a multi-element soil fertilization bio-modifier according to claim 3, characterized in that: In step S5, the mass fraction of the hydrochloric acid solution is 10-15%, the soaking temperature is 90-100°C, and the soaking time is 3-4 hours; the molar ratio of the potassium feldspar powder to the cerium nitrate solution is 1:10-15, the reaction temperature is 80-90°C, and the reaction time is 4-5 hours; In step S6, the mass ratio of alginate oligosaccharide to γ-aminobutyric acid is 3:2, and the mass fraction of the obtained mixed solution is 10-20%.

7. The method for preparing a multi-element soil fertilization bio-modifier according to claim 3, characterized in that: In step S7, the calcination temperature of urea is 500-600° C. and the time is 2-3 hours; In step S8, the mass ratio of glucose, yeast extract and peptone is 1:1:1, and the mass fraction of the sodium hydroxide solution used to remove residual bacteria is 0.1-0.2%.

8. The method for preparing a multi-element soil fertilization bio-modifier according to claim 3, characterized in that: In step S9, the molar ratio of the aniline monomer to ammonium persulfate is 1:1-1.5, the mass fraction of the hydrochloric acid solution is 1 mol / L; the mass fraction of the ammonia water is 10-20%, and the soaking time is 1-2 hours.

9. The method for preparing a multi-element soil fertilization bio-modifier according to claim 3, characterized in that: In step S10, the mass fraction of the suspension is 2-5%, the mass ratio of the ferrous sulfate solution to the montmorillonite is 1:10-15, and the mass fraction of the sodium borohydride solution is 10-20%. In step S11, the conditions for culturing the bacterial population density are: expanding the culture at 28-32° C. and a shaking speed of 150-200 rpm / min, while alternating between hypoxic and oxygen-rich conditions, and gradually increasing the salt concentration to 8% for stress resistance screening.

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