Manufacturing technology and application of multifunctional soil conditioner

Abstract

The invention relates to the technical field of soil conditioning, in particular to a manufacturing technology and application of a multifunctional soil conditioner. The multifunctional soil conditioner is prepared from the following components in percentage by mass: 40 to 45 percent of modified nano gypsum core, 28 to 30 percent of halophilic microbial agent master batch, 11 to 12 percent of sword bean powder extracting solution, 5 to 8 percent of urea, 4 to 6 percent of calcium chloride, 3 to 5 percent of polyethylene glycol 2000 and 1 to 2 percent of alkyl glycoside, efficient replacement and rapid salt reduction of sodium ions are achieved through a modified nano gypsum core, mineralized shells are generated in situ through an enzyme-induced calcium carbonate precipitation technology, the mineralized shells are cemented with soil particles to form a stable aggregate structure, and long-acting remediation of soil micro-ecology is achieved through halophilic microbial agent master batches. The key problems that a traditional modifier is single in function, chemical improvement and biological improvement are difficult to be compatible, and the improvement effect is not lasting are solved, and an efficient, stable and eco-friendly brand-new strategy is provided for saline-alkali soil treatment.

Description

Technical Field

[0001] This invention relates to the field of soil conditioning technology, specifically to a manufacturing technology and application of a multifunctional soil conditioner. Background Technology

[0002] In the field of contemporary saline-alkali land management, soil salinization is evolving into a severe global ecological crisis. Traditional chemical improvement methods rely on the replacement of sodium ions by substances such as gypsum and sulfur. However, this single mode of action has become its inherent defect. After improvement, the soil is prone to compaction and salt rebound, making it difficult to sustain the improvement effect. More challenging is that the high salinity environment has a strong killing effect on microorganisms. Although biological improvement methods can restore soil ecology, they are difficult to be effective in practice due to the low survival rate of microbial agents, forming a dilemma where chemical improvement and biological improvement mutually hinder each other.

[0003] Research has found that synergistically designing chemical desalination and bioremediation in space and time can effectively overcome the limitations of traditional improvement technologies. However, existing technical solutions, which employ simple physical mixing and stepwise application of functional components, fail to achieve precise integration and orderly release of various mechanisms at the particle scale. Specifically, there is a lack of an efficient carrier system that can integrate and programmatically deliver chemical desalination agents, physical structure modifiers, and active microorganisms. This results in mutual interference and dispersal and inactivation of the various functional modules after they are applied to the soil, preventing them from being synchronously and orderly activated and exerting synergistic effects in the saline-alkali environment. This severely restricts the efficient management and ecological restoration of saline-alkali land.

[0004] To address the above problems, the present invention provides a solution. Summary of the Invention

[0005] The purpose of this invention is to provide a multifunctional soil conditioner manufacturing technology and application that can efficiently and stably treat saline-alkali land.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A multifunctional soil conditioner is composed of the following components by mass percentage: 40-45% modified nano-gypsum core, 28-30% halophilic microbial agent masterbatch, 11-12% sword bean powder extract, 5-8% urea, 4-6% calcium chloride, 3-5% polyethylene glycol 2000 and 1-2% alkyl glycosides; Furthermore, the preparation method of the modified nano-gypsum core includes the following steps: A1: Place phosphogypsum in a vacuum drying oven, set the temperature to 85℃ and the vacuum degree to -0.08MPa, and dry for 16h. After drying, transfer it to a vibrating screen and pass it through a 100-mesh sieve to obtain pretreated gypsum powder. Place the pretreated gypsum powder in a muffle furnace and heat it to 180℃ at a heating rate of 5℃ / min. Calcinate it at a constant temperature for 2h. After the constant temperature calcination is completed, allow it to cool naturally to room temperature to obtain activated gypsum powder. A2: Transfer the activated gypsum powder to a ball mill, using a zirconia ball mill jar and zirconia grinding balls, with a mass ratio of grinding balls to activated gypsum powder of 12:1. Then, add triethanolamine and ethylene glycol to the ball mill jar, with a mass ratio of activated gypsum powder, triethanolamine, and ethylene glycol of 1000:3:2. Set the ball mill's revolution speed to 450 rpm and its rotation speed to 900 rpm. After every 30 minutes of ball milling, intermittently cool for 10 minutes, for a total ball milling time of 4 hours. After ball milling, obtain micron-sized activated gypsum powder. A3: Add micron-sized activated gypsum powder to a reaction vessel, along with deionized water, sodium polyacrylate, and nanocellulose. The mass ratio of micron-sized activated gypsum powder, deionized water, sodium polyacrylate, and nanocellulose is 100:500:0.8:0.1. Set the stirrer speed to 500 rpm and stir for 30 minutes. After stirring, transfer the mixture to a high-speed shear emulsifier and set the speed to 10000 rpm. Shear and disperse the mixture for 20 minutes. After shear and dispersion, transfer the mixture to an ultrasonic cell disruptor and set the ultrasonic power to 600W. The working mode is intermittent, with 3 seconds of sonication followed by 2 seconds of intermittent sonication. Sonicate the mixture for 45 minutes under ice-water bath protection to obtain a gypsum suspension. A4: The gypsum suspension was transferred to a circulating nano-sand mill. The grinding media consisted of yttrium-stabilized zirconia microspheres with a diameter of 0.03 mm and a filling rate of 85%. The mill linear speed was set to 12 m / s, the circulating feed rate was 5 L / min, and the grinding temperature was strictly controlled at 25℃ through a circulating cooling system. The mill was circulated and ground for 8 hours. After grinding, the suspension was filtered through a 0.5 μm ceramic membrane filter to obtain nano-gypsum slurry. A5: Weigh out polyaspartic acid and dissolve it in deionized water. Adjust the pH to 8.0 with dilute sodium hydroxide solution to prepare a polyaspartic acid modification solution with a concentration of 20 mg / mL. Then, place the nano-gypsum slurry and the polyaspartic acid modification solution in a jacketed reactor with a mass ratio of 3:1. Set the stirrer speed to 300 rpm and stir for 3 hours under a constant temperature water bath at 50℃. After the stirring reaction is completed, add citric acid and disodium EDTA with a mass ratio of 100:2:1. Adjust the pH to 7.5 and continue stirring for 1 hour at 40℃. After the stirring reaction is completed, transfer to an ultrasonic cleaner, set the ultrasonic power to 200W, and ultrasonically treat for 15 minutes to obtain the composite modified gypsum slurry. A6: The composite modified gypsum slurry was transferred to a regenerated cellulose dialysis bag with a molecular weight cutoff of 3.5 kDa. First, it was dialyzed for 12 hours at 4°C in 0.05 mol / L ammonium carbonate buffer (pH 8.5). Then, it was transferred to deionized water and dialyzed for another 24 hours, with the deionized water changed every 4 hours. During dialysis, the dialysate was continuously and slowly stirred. After dialysis, it was transferred to a spray dryer for microgranulation. The spray dryer parameters were set as follows: inlet air temperature 180°C, outlet air temperature 90°C, a dual-fluid nozzle atomizer, atomization pressure 0.25 MPa, feed rate 20 ml / min, and drying airflow rate 35 m³ / min. 3 After spray drying, the product is fed into an air jet mill and pulverized using supersonic airflow at a pressure of 0.8 MPa and a classifier wheel speed of 4500 rpm. The product is collected using a cyclone separator and a bag filter. Nitrogen protection is used during the pulverization process to obtain modified nano-gypsum powder. A7: Transfer the modified nano-gypsum powder to a vacuum drying oven, set the temperature to 60℃, the vacuum degree to -0.09MPa, and dry for 6 hours. After drying, seal the package in aluminum foil bags under nitrogen protection. Each bag weighs 5kg net. Store the package in a cool, dry warehouse with a moisture-proof container to obtain the modified nano-gypsum core. Furthermore, the preparation method of the halophilic microbial agent masterbatch includes the following steps: B1: Soil from the top 20cm layer of saline-alkali land in Xinjiang was collected and isolated using a high-salt selective medium. After culturing at 30℃ for 48h, single colonies with good growth were selected and streaked for purification three times. The bacteria were identified as Bacillus spp. by 16S rDNA and obtained halophilic Bacillus. B2: Halophilic Bacillus was inoculated into seed culture medium and cultured at 30℃ and 200rpm for 18h to obtain fermentation seed. The fermentation seed was then inoculated into a fermenter containing fermentation culture medium, with a mass ratio of fermentation seed to fermentation culture medium of 5:95. The fermentation temperature was set at 30℃, the stirring speed at 300rpm, and the aeration rate at 1.5vvm. Fermentation was carried out for 36h. After fermentation, the fermentation broth was transferred to a tubular centrifuge and centrifuged at 12000rpm for 15min to collect the bacterial cells, obtaining fermented wet bacterial cells. B3: Add trehalose, skim milk powder, monosodium glutamate, polyvinylpyrrolidone, glycerol, and Tween-80 to a homogenizer and homogenize for 15 minutes to obtain a lyophilization protectant. The mass ratio of trehalose, skim milk powder, monosodium glutamate, polyvinylpyrrolidone, glycerol, and Tween-80 is 50:30:10:5:3:2. Dissolve the lyophilization protectant in sterile deionized water to obtain a lyophilization protectant solution. The mass ratio of the lyophilization protectant to sterile deionized water is 20:80. B4: Add the fermented wet cells and the freeze-drying protectant solution to the reactor, set the stirrer speed to 300 rpm, and stir for 15 min. The mass ratio of the fermented wet cells to the freeze-drying protectant solution is 1:2. After stirring and mixing, dispense and transfer to a sterile freeze-drying tray, pre-freeze at -80℃ for 6 h, and after pre-freezing, transfer to a vacuum freeze dryer. Set the cold trap temperature of the vacuum freeze dryer to -50℃, the vacuum degree to 8 Pa, and the partition temperature program to -20℃, 8 h, -10℃, 6 h, 0℃, 4 h, 10℃, 3 h, and 25℃, 3 h. After freeze-drying, immediately fill with nitrogen and package to obtain Bacillus halophilus dry powder. B5: Humic acid was pulverized through a 100-mesh sieve and then added to a 0.5 mol / L KOH solution, with a mass ratio of humic acid to KOH solution of 1:5. The reaction was carried out at 60℃ for 2 hours, and the activated humic acid was obtained by spray drying. Biochar was pulverized through a 100-mesh sieve and then soaked in a 5% phosphoric acid solution for 12 hours for modification, with a mass ratio of biochar to phosphoric acid solution of 1:3. After the modification was completed, the biochar was washed with water until neutral and then dried to obtain acid-modified biochar. The activated humic acid and acid-modified biochar were added to a homogenizer and homogenized for 5 minutes to obtain a composite primary carrier. The composite primary carrier was transferred to a three-dimensional motion mixer, and diatomaceous earth, sodium carboxymethyl cellulose, and β-cyclodextrin were added. The mixture was mixed for 45 minutes to obtain a composite carrier powder, with a mass ratio of composite primary carrier, diatomaceous earth, sodium carboxymethyl cellulose, and β-cyclodextrin of 100:5:3:2. B6: Add the dry powder of Bacillus halophilus and the composite carrier powder into a horizontal kneader and dry mix for 5 minutes to obtain a primary bacterial carrier mixture, wherein the mass ratio of the dry powder of Bacillus halophilus and the composite carrier powder is 1:4. Then add sterile water and chitosan solution and knead at 60 rpm for 20 minutes, wherein the mass ratio of the primary bacterial carrier mixture, sterile water and chitosan solution is 100:12:2. After kneading, transfer to a single screw extruder granulator, select a 0.6 mm screen, set the screw speed to 40 rpm, the granulation pressure to 5 MPa, and the cooling water temperature to 25 ℃. Extrude the strip material and cut it with a rotary pelletizer to obtain wet masterbatch with a length of 1 mm. B7: Feed the wet masterbatch into a fluidized bed dryer and use a gradient temperature rise process. Dry at 30℃ for 15 minutes, 35℃ for 20 minutes, and 40℃ for 15 minutes, maintaining a material temperature of 35℃ throughout the process. Dry until the moisture content reaches 10%. Add trehalose, skim milk powder, and polyvinyl alcohol to deionized water and stir for 30 minutes to obtain a coating solution. The mass ratio of trehalose, skim milk powder, polyvinyl alcohol, and deionized water is 10:5:2:83. After drying... The mixture was transferred to a coating granulator with an inlet air temperature of 35°C and an atomization pressure of 0.2 MPa. The first coating layer was sprayed until the weight gain was 5%, and then dried for 10 minutes. Gum arabic, gelatin, and glycerin were added to deionized water and stirred for 30 minutes to obtain the second coating layer. The mass ratio of gum arabic, gelatin, glycerin, and deionized water was 3:2:1:94. Under the same conditions, the weight gain was 3%. After coating, the mixture was allowed to cool naturally and then packaged in vacuum aluminum foil bags. It was then allowed to stand at 25°C for 48 hours to obtain the halophilic microbial agent masterbatch. Furthermore, the high-salt selective culture medium mentioned in step B1 comprises 5 g / L yeast extract, 10 g / L peptone, 100 g / L NaCl, 10 g / L Na2CO3, and 20 g / L agar, with a pH of 9.0; the fermentation culture medium mentioned in step B2 comprises 20 g / L corn steep liquor, 15 g / L molasses, 10 g / L soybean meal, 80 g / L NaCl, and 8 g / L Na2CO3, with a pH of 8.5. Furthermore, the preparation method of the sword bean powder extract includes the following steps: C1: Select high-quality white sword beans, grind them in a universal grinder, pass them through a 60-mesh sieve to obtain coarse sword bean powder, place the coarse sword bean powder in an extractor, add petroleum ether, and reflux in a 70℃ water bath for 4 hours to defatt it. After defatting, place the sword bean powder in a fume hood to evaporate and remove residual petroleum ether, and then transfer it to a 40℃ vacuum drying oven to dry for 6 hours to obtain defatted sword bean powder, which is then sealed and stored for later use. C2: Add β-mercaptoethanol, sodium azide, and polyvinylpyrrolidone to phosphate buffer, wherein the mass ratio of β-mercaptoethanol, sodium azide, polyvinylpyrrolidone, and phosphate buffer is 0.1:0.05:0.5:100. Stir and mix for 30 min, then filter through a 0.45 μm filter membrane and pre-cool at 4 °C for 30 min to obtain pre-cooled buffer. C3: Add pre-cooled buffer and defatted kaempferia powder to the reaction vessel, wherein the mass ratio of pre-cooled buffer to defatted kaempferia powder is 8:1. Set the reaction vessel speed to 300 rpm and stir for 15 min. After mixing, transfer to a low-temperature constant temperature shaking incubator, set the temperature to 4℃ and the speed to 150 rpm, and shake for 8 h. After shaking extraction, transfer to a 4℃ cold storage and let stand for 4 h to obtain the extract. C4: Filter the extract coarsely through double-layer gauze, collect the filtrate, transfer the filtrate to a refrigerated centrifuge, set the speed to 8000 rpm and the temperature to 4℃, centrifuge for 15 min, collect the supernatant, add fresh phosphate buffer to the precipitate to resuspend, centrifuge again under the same conditions, the mass ratio of precipitate to fresh phosphate buffer is 1:5, combine the supernatants from the two centrifuges to obtain the crude extract of sword bean; C5: Slowly add finely ground ammonium sulfate powder to the crude extract of sword bean while stirring until the ammonium sulfate saturation reaches 30%. After standing at 4℃ for 2 hours, centrifuge at 8000 rpm for 15 minutes, discard the precipitate, collect the supernatant, and continue to add ammonium sulfate until the saturation reaches 60%. Let stand at 4℃ overnight, and centrifuge at 10000 rpm for 20 minutes the next day to collect the precipitate. Dissolve the precipitate in 0.05 mol / L Tris-HCl buffer solution with pH 7.0 to obtain the concentrated urease solution. C6: The concentrated urease solution was placed into a regenerated cellulose dialysis bag with a molecular weight cutoff of 10 kDa. Before use, the dialysis bag was pretreated by boiling with 2% sodium bicarbonate and 1 mmol / L EDTA for 10 min. The dialysis bag was placed in 50 volumes of 0.01 mol / L phosphate buffer at pH 7.0 and dialyzed magnetically at 4°C for 24 h. The external dialysis solution was replaced every 6 h. After dialysis, the liquid in the dialysis bag was collected to obtain the desalted urease solution. C7: Load the desalted urease solution onto a DEAE-Sepharose Fast Flow anion exchange chromatography column. Equilibrate the column with 0.02 mol / L, pH 7.0 Tris-HCl buffer. After loading, elute unbound proteins with the same buffer at a flow rate of 1 ml / min and collect the elution peak. Then, elute with a linear gradient of 0-0.5 mol / L NaCl at a flow rate of 1 ml / min, collecting 5 ml from each tube. Measure the absorbance at 280 nm and the urease activity in each tube, collect the activity peak, combine the activity peaks, and concentrate them to 1 / 5 of the original volume using an ultrafiltration centrifuge tube with a molecular weight cutoff of 30 kDa to obtain a partially purified urease solution. C8: A portion of the purified urease solution was loaded onto a Sephadex G-200 gel filtration chromatography column and eluted with 0.05 mol / L phosphate buffer at pH 7.0 at a flow rate of 0.3 ml / min. 2 ml of solution was collected from each tube, and the urease activity of each tube was measured. The activity peak was collected to obtain a high-purity urease solution. C9: Add trehalose, mannitol, and EDTA to a high-purity urease solution and stir until homogeneous. The mass ratio of the high-purity urease solution, trehalose, mannitol, and EDTA is 100:2:1:0.5. Dispense the solution into sterile freeze-drying bottles, 10 ml per bottle, and pre-freeze at -80℃ for 4 hours. After pre-freezing, transfer the solution to a freeze dryer, set the cold trap temperature to -50℃, the vacuum degree to 10 Pa, and freeze-dry for 24 hours. Immediately after freeze-drying, seal the solution with nitrogen to obtain freeze-dried sword bean powder extract. Store at 4℃. When using, reconstitute the freeze-dried powder with 10 ml of deionized water per gram to obtain the sword bean powder extract. Furthermore, a method for preparing a multifunctional soil conditioner includes the following steps: S1: The halophilic microbial agent masterbatch is put into a fluidized bed granulator. The fluidized bed inlet air temperature is set to 40℃ and the outlet air temperature to 30℃. The fluidization air volume is adjusted to make the masterbatch in a good fluidized state. The modified nano gypsum core powder and sword bean powder extract are mixed and added to the reaction vessel. Then, polyethylene glycol 2000 and deionized water are added to adjust the solid content to 15%. The mixture is stirred evenly to obtain the first spraying liquid. S2: Dissolve urea and calcium chloride in deionized water to prepare a second spraying solution with a total concentration of 0.5 mol / L. Under fluidized conditions, first spray the first spraying solution onto the halophilic microbial agent masterbatch at a rate of 5 ml / min for 10 min, then spray the second spraying solution at a rate of 3 ml / min. Repeat the spraying of the first and second spraying solutions 3-5 times. After each spraying, dry for 3 min. The drying conditions are: inlet air temperature 45℃, outlet air temperature 35℃, and fluidized air velocity adjusted to 1.5 m / s. Stop spraying when the particle size reaches 1.2-1.5 mm to obtain the primary conditioner. S3: Dissolve alkyl glycosides in deionized water to prepare a 1% solution. Spray the solution onto the surface of the primary conditioner at a rate of 2 ml / min. After complete spraying, dry for 30 min. The drying conditions are: inlet air temperature 50℃, outlet air temperature 40℃, and fluidization velocity adjusted to 1.2 m / s. After drying, sieve and collect particles between 20-40 mesh to obtain a multifunctional soil conditioner. Place it in an aluminum foil bag, seal it with nitrogen gas, and store it in a cool, dry place.

[0007] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: 1. This invention establishes a novel three-tiered synergistic soil improvement model: core colonization, mineralization shell formation, and in-situ cementation. It utilizes halophilic microbial agent masterbatch as the core, enabling long-term survival and functional release of microorganisms in a saline-alkali environment. Enzyme-induced calcium carbonate precipitation technology generates a porous mineralized shell in-situ on the agent surface, exerting a physical desalination effect in the early stages of improvement. The synergistic cementing effect of the modified nano-gypsum core and the mineralized shell solidifies loose soil particles into stable micro-aggregates, systematically solving the key problems of traditional saline-alkali soil conditioners having limited functionality, incompatibility between chemical and biological improvement methods, and unsustainable improvement effects. 2. This invention utilizes a modified nano-gypsum core, halophilic microbial agent masterbatch, and a sword bean powder extract / urea / calcium chloride enzyme-induced mineralization system as its core to construct a multi-component functionally integrated biomimetic mineralization particle. Each component works in precise synergy in spatial structure and timing of action. The modified nano-gypsum is responsible for rapidly replacing sodium ions and providing a calcium source. Urease in the sword bean powder extract catalyzes the decomposition of urea to generate carbonate ions, which combine with calcium ions to form a calcium carbonate shell. The halophilic microbial agent is responsible for long-term improvement of the soil microecology. In terms of its mechanism of action, this invention achieves comprehensive and irreversible improvement of saline-alkali land from ion replacement and aggregate construction to ecological restoration, showing particularly outstanding effects in areas with high salinity and alkalinity and prone to salinization. 3: This invention successfully integrates functional components with vastly different properties, such as chemical modifiers, biological enzyme systems, and active microbial agents, into the core-shell structure of a single particle through a fluidized bed layer-by-layer self-assembly process. This forms biomimetic mineralization particles with spatial hierarchy and temporal release characteristics, which greatly enhances the durability of the improvement effect and provides a new, efficient, precise, and eco-friendly strategy for the treatment of saline-alkali land. Detailed Implementation

[0008] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0009] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0010] Example 1 1. Place 5 kg of phosphogypsum in a vacuum drying oven, set the temperature to 85℃ and the vacuum degree to -0.08 MPa, and dry for 16 h. After drying, transfer it to a vibrating screen and pass it through a 100-mesh sieve to obtain 4925 g of pretreated gypsum powder. Place the pretreated gypsum powder in a muffle furnace and heat it to 180℃ at a heating rate of 5℃ / min. Calcinate it at a constant temperature for 2 h. After the constant temperature calcination is completed, allow it to cool naturally to room temperature to obtain 4710 g of activated gypsum powder. 2: 4.5 kg of activated gypsum powder was transferred to a ball mill. A zirconia ball mill jar and zirconia grinding balls were used, with a total mass of 54 kg of zirconia grinding balls. Then, 13.5 g of triethanolamine and 9 g of ethylene glycol were added to the ball mill jar. The ball mill was set to an orbital speed of 450 rpm and a rotational speed of 900 rpm. The mill was intermittently cooled for 10 minutes after every 30 minutes of milling. The total milling time was 4 hours. After the milling was completed, 4430 g of micron-sized activated gypsum powder was obtained. 3: Add 4250g of micron-sized activated gypsum powder to a reaction vessel, along with 21.25kg of deionized water, 34g of sodium polyacrylate, and 4.25g of nanocellulose. Set the stirrer speed to 500rpm and stir for 30min. After stirring, transfer the mixture to a high-speed shear emulsifier and set the speed to 10000rpm. Shear and disperse the mixture for 20min. After shear and dispersion, transfer the mixture to an ultrasonic cell disruptor and set the ultrasonic power to 600W. The working mode is intermittent, with 3s of sonication followed by 2s of intermittent sonication. Sonicate for 45min under ice-water bath protection to obtain 25.5kg of gypsum suspension. 4. Transfer 25 kg of gypsum suspension to a circulating nano-sand mill. The grinding media is yttrium-stabilized zirconia microspheres with a diameter of 0.03 mm and a filling rate of 85%. Set the mill linear speed to 12 m / s and the circulating feed rate to 5 L / min. The grinding temperature is strictly controlled at 25℃ through the circulating cooling system. Circulate and grind for 8 hours. After grinding, filter the suspension through a 0.5 μm ceramic membrane filter for cross-flow filtration to obtain 23.25 kg of nano-gypsum slurry. 5: Weigh 150g of polyaspartic acid and dissolve it in 7.5L of deionized water. Adjust the pH to 8.0 with dilute sodium hydroxide solution to prepare a polyaspartic acid modification solution with a concentration of 20mg / mL. Then, place 22.5kg of nano-gypsum slurry and 7.5kg of polyaspartic acid modification solution in a jacketed reactor. Set the stirrer speed to 300rpm and stir for 3h under a constant temperature water bath at 50℃. After the stirring reaction is completed, add 450g of citric acid and 225g of disodium ethylenediaminetetraacetate and adjust the pH to 7.5. Continue stirring for 1h at 40℃. After the stirring reaction is completed, transfer it to an ultrasonic cleaner, set the ultrasonic power to 200W, and ultrasonically treat for 15min to obtain 3kg of composite modified gypsum slurry. 6. Transfer 3 kg of composite modified gypsum slurry to a regenerated cellulose dialysis bag with a molecular weight cutoff of 3.5 kDa. First, dialyze in 0.05 mol / L ammonium carbonate buffer (pH 8.5) at 4°C for 12 h. Then, transfer to deionized water and continue dialyzing for 24 h, changing the deionized water every 4 h. During dialysis, the dialysate is continuously and slowly stirred. After dialysis, transfer to a spray dryer for microgranulation. The spray dryer parameters are set as follows: inlet air temperature 180°C, outlet air temperature 90°C, a dual-fluid nozzle atomizer, atomization pressure 0.25 MPa, feed rate 20 ml / min, and drying airflow rate 35 m / min. 3 After spray drying, the product is fed into an air jet mill and pulverized using supersonic air jet milling at a pressure of 0.8 MPa and a classifier wheel speed of 4500 rpm. The product is collected using a cyclone separator and a bag filter. Nitrogen protection is used during the pulverization process to obtain 3.375 kg of modified nano-gypsum powder. 7: The modified nano-gypsum powder was transferred to a vacuum drying oven, the temperature was set at 60℃ and the vacuum degree was -0.09MPa, and dried for 6 hours. After drying, it was sealed in aluminum foil bags under nitrogen protection, with a net weight of 5kg per bag. The bags were then stored in a cool and dry warehouse with a moisture-proof container to obtain 3.375kg of the modified nano-gypsum core prepared in Example 1. Example 2 1: 500g of 20cm topsoil was collected from saline-alkali land in Xinjiang. The soil was isolated and cultured using a high-salt selective medium. After culturing at 30℃ for 48h, single colonies with good growth were selected and streaked three times for purification. The bacteria were identified as Bacillus spp. by 16S rDNA and obtained halophilic Bacillus. 2: Halophilic Bacillus was inoculated into seed culture medium and cultured at 30℃ and 200rpm for 18h to obtain 5kg of fermentation seed. Then, 5kg of fermentation seed was inoculated into a fermenter containing 95kg of fermentation culture medium. The fermentation temperature was set at 30℃, the stirring speed at 300rpm, and the aeration rate at 1.5vvm. Fermentation was carried out for 36h. After fermentation, the fermentation broth was transferred to a tubular centrifuge and centrifuged at 12000rpm for 15min to collect the bacterial cells, yielding 3.2kg of wet fermentation cells. 3: Add 1000g trehalose, 600g skim milk powder, 200g monosodium glutamate, 100g polyvinylpyrrolidone, 60g glycerin and 40g Tween-80 to a homogenizer and homogenize for 15 minutes to obtain 2kg of freeze-drying protectant. Dissolve the freeze-drying protectant in 8kg of sterile deionized water to obtain a freeze-drying protectant solution. 4: Add 3 kg of wet fermentation cells and 6 kg of freeze-drying protectant solution to the reactor. Set the stirrer speed to 300 rpm and stir for 15 min. After stirring and mixing, dispense and transfer to sterile freeze-drying trays. Pre-freeze at -80℃ for 6 h. After pre-freezing, transfer to a vacuum freeze dryer. Set the cold trap temperature of the vacuum freeze dryer to -50℃, the vacuum degree to 8 Pa, and the partition temperature program to -20℃ for 8 h, -10℃ for 6 h, 0℃ for 4 h, 10℃ for 3 h, and 25℃ for 3 h. Immediately after freeze-drying, fill with nitrogen and package to obtain 2.15 kg of Bacillus halophilus dry powder. 5: 1 kg of humic acid was pulverized through a 100-mesh sieve and then added to 5 kg of 0.5 mol / L KOH solution. The reaction was activated at 60℃ for 2 h, and the mixture was spray-dried to obtain 850 g of activated humic acid. 800 g of biochar was pulverized through a 100-mesh sieve and then added to 2.4 kg of 5% phosphoric acid solution for soaking and modification for 12 h. After soaking and modification, the biochar was washed with water until neutral and then dried to obtain 720 g of acid-modified biochar. 800 g of activated humic acid and 200 g of acid-modified biochar were added to a homogenizer and homogenized for 5 min to obtain 1 kg of composite primary carrier. The composite primary carrier was transferred to a three-dimensional motion mixer and 50 g of diatomaceous earth, 30 g of sodium carboxymethyl cellulose and 20 g of β-cyclodextrin were added. The mixture was mixed for 45 min to obtain composite carrier powder. 6: Add 200g of halophilic Bacillus dry powder and 800g of composite carrier powder to a horizontal kneader and dry mix for 5 minutes to obtain 1kg of primary bacterial carrier mixture. Then add 120g of sterile water and 20g of chitosan solution and knead at 60rpm for 20 minutes. After kneading, transfer to a single-screw extruder granulator. Use a 0.6mm screen, set the screw speed to 40rpm, the granulation pressure to 5MPa, and the cooling water temperature to 25℃. Extrude the strip material and cut it with a rotary pelletizer to obtain 1210g of wet masterbatch with a length of 1mm. 7: 1200g of wet masterbatch was put into a fluidized bed dryer and dried using a gradient heating process. The inlet air temperature was 30℃ for 15 min, 35℃ for 20 min, and 40℃ for 15 min. The material temperature was set at 35℃ throughout the process. The drying was stopped when the moisture content was 10%. 100g of trehalose, 50g of skim milk powder and 20g of polyvinyl alcohol were added to 830g of deionized water and stirred for 30 min to obtain a coating liquid. After drying, the mixture was transferred to a coating granulator with an inlet air temperature of 35℃ and an atomization pressure of 0.2MPa. The first coating liquid was sprayed until the weight gain was 5%, and then dried for 10 min. 30g of gum arabic, 20g of gelatin and 10g of glycerin were added to 940g of deionized water and stirred for 30 min to obtain a second coating liquid. The weight gain was 3% under the same conditions. After coating, the mixture was allowed to cool naturally and then packaged in a vacuum aluminum foil bag. It was left to stand at 25℃ for 48 h to obtain 1070g of the halophilic microbial agent masterbatch prepared in Example 2. Example 3 1. Select 5 kg of high-quality white sword beans, grind them in a universal grinder, pass them through a 60-mesh sieve to obtain 4850 g of coarse sword bean powder. Place the coarse sword bean powder in an extractor, add petroleum ether, and reflux in a 70℃ water bath for 4 hours to defatt it. After defatting, place the sword bean powder in a fume hood to evaporate and remove residual petroleum ether, and then transfer it to a 40℃ vacuum drying oven to dry for 6 hours to obtain 4320 g of defatted sword bean powder. Seal and store for later use. 2: Add 20g β-mercaptoethanol, 10g sodium azide and 100g polyvinylpyrrolidone to 20kg phosphate buffer, stir and mix for 30min, then filter through a 0.45um filter membrane and pre-cool at 4℃ for 30min to obtain pre-cooled buffer. 3: Add 16 kg of pre-cooled buffer solution and 2 kg of defatted sword bean powder to the reaction vessel. Set the reaction vessel speed to 300 rpm and stir for 15 min. After mixing, transfer to a low-temperature constant temperature shaking incubator. Set the temperature to 4℃ and the speed to 150 rpm and shake for 8 h. After shaking extraction, transfer to a 4℃ cold storage and let it stand for 4 h to obtain 17.8 kg of extract. 4. Filter the extract coarsely through double-layer gauze, collect the filtrate, transfer the filtrate to a refrigerated centrifuge, set the speed to 8000 rpm and the temperature to 4℃, centrifuge for 15 min, collect the supernatant, add fresh phosphate buffer to the precipitate to resuspend, and centrifuge again under the same conditions, with the mass ratio of precipitate to fresh phosphate buffer being 1:5. Combine the supernatants from both centrifugia to obtain 17.6 kg of crude sword bean extract. 5. Slowly add finely ground ammonium sulfate powder to the crude extract of sword bean while stirring until the ammonium sulfate saturation reaches 30%. After standing at 4℃ for 2 hours, centrifuge at 8000 rpm for 15 minutes, discard the precipitate, collect the supernatant, and continue to add ammonium sulfate until the saturation reaches 60%. Let stand at 4℃ overnight, and centrifuge at 10000 rpm for 20 minutes the next day to collect the precipitate. Dissolve the precipitate in 0.05 mol / L Tris-HCl buffer at pH 7.0 to obtain 450 ml of urease concentrate. 6: 450 ml of urease concentrate was placed into a regenerated cellulose dialysis bag with a molecular weight cutoff of 10 kDa. Before use, the dialysis bag was pretreated by boiling with 2% sodium bicarbonate and 1 mmol / L EDTA for 10 min. The dialysis bag was placed in 50 volumes of 0.01 mol / L phosphate buffer at pH 7.0 and dialyzed magnetically at 4 °C for 24 h. The external dialysis solution was changed every 6 h. After dialysis, the liquid in the dialysis bag was collected to obtain 465 ml of desalted urease solution. 7: Load the desalted urease solution onto a DEAE-Sepharose Fast Flow anion exchange chromatography column. Equilibrate the column with 0.02 mol / L, pH 7.0 Tris-HCl buffer. After loading, elute unbound proteins with the same buffer at a flow rate of 1 ml / min and collect the elution peak. Then, elute with a linear gradient of 0-0.5 mol / L NaCl at a flow rate of 1 ml / min, collecting 5 ml from each tube. Measure the absorbance at 280 nm and the urease activity in each tube, collect the activity peak, combine the activity peaks, and concentrate them to 1 / 5 of the original volume using an ultrafiltration centrifuge tube with a molecular weight cutoff of 30 kDa to obtain 44 ml of partially purified urease solution. 8: Load 44 ml of partially purified urease solution onto a Sephadex G-200 gel filtration chromatography column, elute with 0.05 mol / L phosphate buffer at pH 7.0, at a flow rate of 0.3 ml / min, collect 2 ml from each tube, measure the urease activity of each tube, collect the activity peak, and obtain 36 kg of high-purity urease solution. 9: Add 0.72g trehalose, 0.36g mannitol and 0.18g EDTA to the high-purity urease solution, stir well, dispense into sterile freeze-drying bottles, 10ml per bottle, pre-freeze at -80℃ for 4h, after pre-freezing, transfer to a freeze dryer, set the cold trap temperature to -50℃, vacuum degree to 10Pa, freeze-dry for 24h, immediately fill with nitrogen and seal after freeze-drying to obtain 4.2g of canavalia flour extract freeze-dried powder, store at 4℃, when using, add 10ml of deionized water per gram of freeze-dried powder to reconstitute to obtain the canavalia flour extract prepared in Example 3; Example 4 1: 2800g of the halophilic microbial agent masterbatch prepared in Example 2 was put into a fluidized bed granulator. The fluidized bed inlet air temperature was set to 40℃ and the outlet air temperature to 30℃. The fluidized air volume was adjusted to ensure that the masterbatch was in a good fluidized state. 4000g of the modified nano-gypsum core powder prepared in Example 1 and 1100g of the sword bean powder extract prepared in Example 3 were mixed and added to the reaction vessel. Then 500g of polyethylene glycol 2000 and deionized water were added to adjust the solid content to 15%. The mixture was stirred evenly to obtain the first spraying liquid. 2: Dissolve 800g of urea and 600g of calcium chloride in deionized water to prepare a second spraying solution with a total concentration of 0.5mol / L. Under fluidized conditions, first spray the first spraying solution onto the halophilic microbial agent masterbatch at a rate of 5ml / min for 10min, then spray the second spraying solution at a rate of 3ml / min. Repeat the spraying of the first and second spraying solutions 5 times. After each spraying, dry for 3min. The drying conditions are: inlet air temperature 45℃, outlet air temperature 35℃, and fluidized air velocity adjusted to 1.5m / s. Stop spraying when the particle size reaches 1.5mm to obtain the primary conditioning agent. 3: Dissolve 200g of alkyl glycoside in deionized water to prepare a 1% solution. Spray the solution onto the surface of the primary conditioner at a rate of 2ml / min. After spraying, dry for 30min. The drying conditions are: inlet air temperature 50℃, outlet air temperature 40℃, and fluidizing air velocity adjusted to 1.2m / s. After drying, sieve and collect particles between 20-40 mesh to obtain the multifunctional soil conditioner prepared in Example 4. Place it in an aluminum foil bag, seal it with nitrogen gas, and store it in a cool, dry place.

[0011] Example 5 1: 3000g of the halophilic microbial agent masterbatch prepared in Example 2 was put into a fluidized bed granulator. The fluidized bed inlet air temperature was set to 40℃ and the outlet air temperature to 30℃. The fluidized air volume was adjusted to ensure that the masterbatch was in a good fluidized state. 4500g of the modified nano-gypsum core powder prepared in Example 1 and 1200g of the sword bean powder extract prepared in Example 3 were mixed and added to the reaction vessel. Then 300g of polyethylene glycol 2000 and deionized water were added to adjust the solid content to 15%. The mixture was stirred evenly to obtain the first spraying liquid. 2: Dissolve 500g of urea and 400g of calcium chloride in deionized water to prepare a second spraying solution with a total concentration of 0.5mol / L. Under fluidized conditions, first spray the first spraying solution onto the halophilic microbial agent masterbatch at a rate of 5ml / min for 10min, then spray the second spraying solution at a rate of 3ml / min. Repeat the spraying of the first and second spraying solutions 3 times. After each spraying, dry for 3min. The drying conditions are: inlet air temperature 45℃, outlet air temperature 35℃, and fluidized air velocity adjusted to 1.5m / s. Stop spraying when the particle size reaches 1.2mm to obtain the primary conditioning agent. 3: Dissolve 100g of alkyl glycoside in deionized water to prepare a 1% solution. Spray the solution onto the surface of the primary conditioner at a rate of 2ml / min. After complete spraying, dry for 30min. The drying conditions are: inlet air temperature 50℃, outlet air temperature 40℃, and fluidization velocity adjusted to 1.2m / s. After drying, sieve and collect particles between 20-40 mesh to obtain the multifunctional soil conditioner prepared in Example 5. Place it in an aluminum foil bag, seal it with nitrogen gas, and store it in a cool, dry place.

[0012] Comparative Example 1 1. 2800g of blank masterbatch was put into a fluidized bed granulator. The fluidized bed inlet air temperature was set to 40℃ and the outlet air temperature to 30℃. The fluidizing air volume was adjusted to ensure that the masterbatch was in a good fluidized state. The blank masterbatch was prepared using the same method as in Example 2, but no halophilic Bacillus powder was added during the preparation process. It was made only from composite carrier powder through kneading, granulation, drying and coating. 4000g of modified nano-gypsum core powder prepared in Example 1 and 1100g of sword bean powder extract prepared in Example 3 were mixed and added to the reaction vessel. Then 500g of polyethylene glycol 2000 and deionized water were added to adjust the solid content to 15%. The mixture was stirred evenly to obtain the first spraying liquid. 2: Dissolve 800g of urea and 600g of calcium chloride in deionized water to prepare a second spraying solution with a total concentration of 0.5mol / L. Under fluidized conditions, first spray the first spraying solution onto the halophilic microbial agent masterbatch at a rate of 5ml / min for 10min, then spray the second spraying solution at a rate of 3ml / min. Repeat the spraying of the first and second spraying solutions 5 times. After each spraying, dry for 3min. The drying conditions are: inlet air temperature 45℃, outlet air temperature 35℃, and fluidized air velocity adjusted to 1.5m / s. Stop spraying when the particle size reaches 1.5mm to obtain the primary conditioning agent. 3: Dissolve 200g of alkyl glycoside in deionized water to prepare a 1% solution. Spray the solution onto the surface of the primary conditioner at a rate of 2ml / min. After complete spraying, dry for 30min. The drying conditions are: inlet air temperature 50℃, outlet air temperature 40℃, and fluidization velocity adjusted to 1.2m / s. After drying, sieve and collect particles between 20-40 mesh to obtain the multifunctional soil conditioner prepared in Comparative Example 1. Place it in an aluminum foil bag, seal it with nitrogen gas, and store it in a cool, dry place.

[0013] Comparative Example 2 1: 2800g of the halophilic microbial agent masterbatch prepared in Example 2 was put into a fluidized bed granulator. The fluidized bed inlet air temperature was set to 40℃ and the outlet air temperature to 30℃. The fluidized air volume was adjusted to ensure that the masterbatch was in a good fluidized state. 4000g of the modified nano-gypsum core powder prepared in Example 1 and 1100g of sodium cellulose were mixed and added to the reaction vessel. Then 500g of polyethylene glycol 2000 and deionized water were added to adjust the solid content to 15%. The mixture was stirred evenly to obtain the first spraying liquid. 2: Dissolve 800g of urea and 600g of calcium chloride in deionized water to prepare a second spraying solution with a total concentration of 0.5mol / L. Under fluidized conditions, first spray the first spraying solution onto the halophilic microbial agent masterbatch at a rate of 5ml / min for 10min, then spray the second spraying solution at a rate of 3ml / min. Repeat the spraying of the first and second spraying solutions 5 times. After each spraying, dry for 3min. The drying conditions are: inlet air temperature 45℃, outlet air temperature 35℃, and fluidized air velocity adjusted to 1.5m / s. Stop spraying when the particle size reaches 1.5mm to obtain the primary conditioning agent. 3: Dissolve 200g of alkyl glycoside in deionized water to prepare a 1% solution. Spray the solution onto the surface of the primary conditioner at a rate of 2ml / min. After complete spraying, dry for 30min. The drying conditions are: inlet air temperature 50℃, outlet air temperature 40℃, and fluidizing air velocity adjusted to 1.2m / s. After drying, sieve and collect particles between 20-40 mesh to obtain the multifunctional soil conditioner prepared in Comparative Example 2. Place it in an aluminum foil bag, seal it with nitrogen gas, and store it in a cool, dry place.

[0014] Field test of the effect of saline-alkali land improvement The experimental site was selected in a typical saline-alkali land demonstration area in Yuli County, Bayingolin Mongol Autonomous Prefecture, Xinjiang, at 86°15′E and 41°20′N. This region has a warm temperate continental desert climate with an average annual precipitation of 45 mm and an evaporation rate exceeding 2500 mm. The tested soil was chloride-sulfate saline-alkali soil. The basic physicochemical properties of the 0-20 cm topsoil layer were: pH 9.8, total salt content 8.5 g / kg, exchangeable sodium content 4.2 cmol / kg, alkalinity 32.5%, organic matter content 6.5 g / kg, and soil bulk density 1.35 g / cm³. 3 The proportion of aggregates larger than 0.25 mm was 18.5%; The experiment consisted of 5 treatments, each with 3 replicates, arranged in a randomized block design, with a plot size of 20m². 2 (5m×4m), with a 1m wide protective row between sections; Table 1. Experimental Grouping and Treatment Table

[0015] Application method: On March 25, 2025 (before spring sowing), each conditioner was evenly spread on the surface of the corresponding plot. A rotary tiller was used to plow the soil to a depth of 20cm to ensure the conditioner was thoroughly mixed with the topsoil. After plowing, the land was leveled, and each plot was uniformly flooded with 120m³ of water to suppress salt. 3 / mu. After irrigation, allow the soil to dry naturally, and then uniformly sow sunflowers (variety: Xin Kui Za No. 5) on April 15, 2025, followed by conventional field management; Sampling and Measurement Methods On July 15, 2025 (the peak flowering period of sunflowers), soil samples from the 0-20cm topsoil layer were collected in each plot using the five-point sampling method. After being mixed evenly, the samples were brought back to the laboratory to air dry and sieve. The indicators are shown in Table 2. Table 2. Measurement Indicators and Methods

[0016] Table 3, Measurement Results

[0017] Analysis of Table 3 shows that... After applying the conditioner from Example 4, the soil pH decreased from 9.8 to 8.3, a decrease of 1.5 units; the total salt content decreased from 8.5 g / kg to 3.8 g / kg, a salt reduction rate of 55.3%; the exchangeable sodium decreased from 4.2 cmol / kg to 1.6 cmol / kg, a decrease of 61.9%; and the soil bulk density decreased from 1.35 g / cm³. 3 Reduced to 1.16 g / cm³ 3 The percentage of soil aggregates with a diameter greater than 0.25 mm decreased by 14.1%; the percentage of aggregates with a diameter greater than 0.25 mm increased from 18.5% to 58.6%, a 2.17-fold increase; and the number of viable soil bacteria increased from 1.2 × 10⁻⁶. 4 CFU / g increased to 3.6×10 6 The CFU / g was increased by 300 times; the sunflower plant height increased from 85cm to 142cm, and the yield increased by 90.4%. All indicators were optimal, indicating that the synergistic effect of the complete formula was the best. Example 5 showed slightly lower performance across the board than T2. ​​Due to fewer spraying cycles and a thinner biomimetic mineralized shell, the overall improvement was still significant, with a salt reduction rate of 50.6% and a yield increase of 80.8%. Comparative Example 1, which does not contain halophilic microbial agents but does contain a modified nano-gypsum core and sword bean powder extract, can form a biomimetic mineralized shell. Its chemical and physical structure improvement effects are similar to T2: salt reduction rate of 52.9%, improved aggregate structure to 57.2%, and increased sunflower yield by 84.8%, but the soil viable bacteria count was only 1.1 × 10⁻⁶. 4 The CFU / g level was comparable to the blank control, indicating a lack of long-term microbial improvement function and insufficient soil microecological restoration capacity in the long run. Compared to Example 2, using sodium cellulose instead of sword bean flour extract failed to form a stable biomimetic mineralized outer shell. The improvement effect was significantly lower than T2: salt reduction rate was only 23.5%, aggregate structure was only 31.8%, and sunflower yield increase was only 34.4%. Although the soil viable bacteria count reached 2.8 × 10⁻⁶, the overall effect was still poor. 6 However, due to the lack of a mineralized shell for protection, the microorganisms have a low survival rate in saline-alkali environments and cannot block capillary action, resulting in weak resistance to salt return.

[0018] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A multifunctional soil conditioner, characterized in that, It is composed of the following components by weight percentage: 40-45% modified nano-gypsum core, 28-30% halophilic microbial agent masterbatch, 11-12% sword bean powder extract, 5-8% urea, 4-6% calcium chloride, 3-5% polyethylene glycol 2000 and 1-2% alkyl glycosides.

2. The multifunctional soil conditioner according to claim 1, characterized in that, The method for preparing the modified nano-gypsum core includes the following steps: A1: Place phosphogypsum in a vacuum drying oven, set the temperature to 85℃ and the vacuum degree to -0.08MPa, and dry for 16h. After drying, transfer it to a vibrating screen and pass it through a 100-mesh sieve to obtain pretreated gypsum powder. Place the pretreated gypsum powder in a muffle furnace and heat it to 180℃ at a heating rate of 5℃ / min. Calcinate it at a constant temperature for 2h. After the constant temperature calcination is completed, allow it to cool naturally to room temperature to obtain activated gypsum powder. A2: Transfer the activated gypsum powder to a ball mill, using a zirconia ball mill jar and zirconia grinding balls, with a mass ratio of grinding balls to activated gypsum powder of 12:

1. Then, add triethanolamine and ethylene glycol to the ball mill jar, with a mass ratio of activated gypsum powder, triethanolamine, and ethylene glycol of 1000:3:

2. Set the ball mill's revolution speed to 450 rpm and its rotation speed to 900 rpm. After every 30 minutes of ball milling, intermittently cool for 10 minutes, for a total ball milling time of 4 hours. After ball milling, obtain micron-sized activated gypsum powder. A3: Add micron-sized activated gypsum powder to a reaction vessel, along with deionized water, sodium polyacrylate, and nanocellulose. The mass ratio of micron-sized activated gypsum powder, deionized water, sodium polyacrylate, and nanocellulose is 100:500:0.8:0.

1. Set the stirrer speed to 500 rpm and stir for 30 minutes. After stirring, transfer the mixture to a high-speed shear emulsifier and set the speed to 10000 rpm. Shear and disperse the mixture for 20 minutes. After shear and dispersion, transfer the mixture to an ultrasonic cell disruptor and set the ultrasonic power to 600W. The working mode is intermittent, with 3 seconds of sonication followed by 2 seconds of intermittent sonication. Sonicate the mixture for 45 minutes under ice-water bath protection to obtain a gypsum suspension. A4: The gypsum suspension was transferred to a circulating nano-sand mill. The grinding media consisted of yttrium-stabilized zirconia microspheres with a diameter of 0.03 mm and a filling rate of 85%. The mill linear speed was set to 12 m / s, the circulating feed rate was 5 L / min, and the grinding temperature was strictly controlled at 25℃ through a circulating cooling system. The mill was circulated and ground for 8 hours. After grinding, the suspension was filtered through a 0.5 μm ceramic membrane filter to obtain nano-gypsum slurry. A5: Weigh out polyaspartic acid and dissolve it in deionized water. Adjust the pH to 8.0 with dilute sodium hydroxide solution to prepare a polyaspartic acid modification solution with a concentration of 20 mg / mL. Then, place the nano-gypsum slurry and the polyaspartic acid modification solution in a jacketed reactor with a mass ratio of 3:

1. Set the stirrer speed to 300 rpm and stir for 3 hours under a constant temperature water bath at 50℃. After the stirring reaction is completed, add citric acid and disodium EDTA with a mass ratio of 100:2:

1. Adjust the pH to 7.5 and continue stirring for 1 hour at 40℃. After the stirring reaction is completed, transfer to an ultrasonic cleaner, set the ultrasonic power to 200W, and ultrasonically treat for 15 minutes to obtain the composite modified gypsum slurry. A6: The composite modified gypsum slurry was transferred to a regenerated cellulose dialysis bag with a molecular weight cutoff of 3.5 kDa. First, it was dialyzed for 12 hours at 4°C in 0.05 mol / L ammonium carbonate buffer (pH 8.5). Then, it was transferred to deionized water and dialyzed for another 24 hours, with the deionized water changed every 4 hours. During dialysis, the dialysate was continuously and slowly stirred. After dialysis, it was transferred to a spray dryer for microgranulation. The spray dryer parameters were set as follows: inlet air temperature 180°C, outlet air temperature 90°C, a dual-fluid nozzle atomizer, atomization pressure 0.25 MPa, feed rate 20 ml / min, and drying airflow rate 35 m³ / min. 3 After spray drying, the product is fed into an air jet mill and pulverized using supersonic airflow at a pressure of 0.8 MPa and a classifier wheel speed of 4500 rpm. The product is collected using a cyclone separator and a bag filter. Nitrogen protection is used during the pulverization process to obtain modified nano-gypsum powder. A7: Transfer the modified nano-gypsum powder to a vacuum drying oven, set the temperature to 60℃, the vacuum degree to -0.09MPa, and dry for 6 hours. After drying, seal the package in aluminum foil bags under nitrogen protection, with each bag weighing 5kg net. Store the package in a cool, dry warehouse with a moisture-proof container to obtain the modified nano-gypsum core.

3. The multifunctional soil conditioner according to claim 1, characterized in that, The preparation method of the halophilic microbial agent masterbatch includes the following steps: B1: Soil from the top 20cm layer of saline-alkali land in Xinjiang was collected and isolated using a high-salt selective medium. After culturing at 30℃ for 48h, single colonies with good growth were selected and streaked for purification three times. The bacteria were identified as Bacillus spp. by 16S rDNA and obtained halophilic Bacillus. B2: Halophilic Bacillus was inoculated into seed culture medium and cultured at 30℃ and 200rpm for 18h to obtain fermentation seed. The fermentation seed was then inoculated into a fermenter containing fermentation culture medium, with a mass ratio of fermentation seed to fermentation culture medium of 5:

95. The fermentation temperature was set at 30℃, the stirring speed at 300rpm, and the aeration rate at 1.5vvm. Fermentation was carried out for 36h. After fermentation, the fermentation broth was transferred to a tubular centrifuge and centrifuged at 12000rpm for 15min to collect the bacterial cells, obtaining fermented wet bacterial cells. B3: Add trehalose, skim milk powder, monosodium glutamate, polyvinylpyrrolidone, glycerol, and Tween-80 to a homogenizer and homogenize for 15 minutes to obtain a lyophilization protectant. The mass ratio of trehalose, skim milk powder, monosodium glutamate, polyvinylpyrrolidone, glycerol, and Tween-80 is 50:30:10:5:3:

2. Dissolve the lyophilization protectant in sterile deionized water to obtain a lyophilization protectant solution. The mass ratio of the lyophilization protectant to sterile deionized water is 20:

80. B4: Add the fermented wet cells and the freeze-drying protectant solution to the reactor, set the stirrer speed to 300 rpm, and stir for 15 min. The mass ratio of the fermented wet cells to the freeze-drying protectant solution is 1:

2. After stirring and mixing, dispense and transfer to a sterile freeze-drying tray, pre-freeze at -80℃ for 6 h, and after pre-freezing, transfer to a vacuum freeze dryer. Set the cold trap temperature of the vacuum freeze dryer to -50℃, the vacuum degree to 8 Pa, and the partition temperature program to -20℃, 8 h, -10℃, 6 h, 0℃, 4 h, 10℃, 3 h, and 25℃, 3 h. After freeze-drying, immediately fill with nitrogen and package to obtain Bacillus halophilus dry powder. B5: Humic acid was pulverized through a 100-mesh sieve and then added to a 0.5 mol / L KOH solution, with a mass ratio of humic acid to KOH solution of 1:

5. The reaction was carried out at 60℃ for 2 hours, and the activated humic acid was obtained by spray drying. Biochar was pulverized through a 100-mesh sieve and then soaked in a 5% phosphoric acid solution for 12 hours for modification, with a mass ratio of biochar to phosphoric acid solution of 1:

3. After the modification was completed, the biochar was washed with water until neutral and then dried to obtain acid-modified biochar. The activated humic acid and acid-modified biochar were added to a homogenizer and homogenized for 5 minutes to obtain a composite primary carrier. The composite primary carrier was transferred to a three-dimensional motion mixer, and diatomaceous earth, sodium carboxymethyl cellulose, and β-cyclodextrin were added. The mixture was mixed for 45 minutes to obtain a composite carrier powder, with a mass ratio of composite primary carrier, diatomaceous earth, sodium carboxymethyl cellulose, and β-cyclodextrin of 100:5:3:

2. B6: Add the dry powder of Bacillus halophilus and the composite carrier powder into a horizontal kneader and dry mix for 5 minutes to obtain a primary bacterial carrier mixture, wherein the mass ratio of the dry powder of Bacillus halophilus and the composite carrier powder is 1:

4. Then add sterile water and chitosan solution and knead at 60 rpm for 20 minutes, wherein the mass ratio of the primary bacterial carrier mixture, sterile water and chitosan solution is 100:12:

2. After kneading, transfer to a single screw extruder granulator, select a 0.6 mm screen, set the screw speed to 40 rpm, the granulation pressure to 5 MPa, and the cooling water temperature to 25 ℃. Extrude the strip material and cut it with a rotary pelletizer to obtain wet masterbatch with a length of 1 mm. B7: Feed the wet masterbatch into a fluidized bed dryer and use a gradient temperature rise process. Dry at 30℃ for 15 minutes, 35℃ for 20 minutes, and 40℃ for 15 minutes, maintaining a material temperature of 35℃ throughout the process. Dry until the moisture content reaches 10%. Add trehalose, skim milk powder, and polyvinyl alcohol to deionized water and stir for 30 minutes to obtain a coating solution. The mass ratio of trehalose, skim milk powder, polyvinyl alcohol, and deionized water is 10:5:2:

83. After drying... The mixture was transferred to a coating granulator with an inlet air temperature of 35°C and an atomization pressure of 0.2 MPa. The first coating layer was sprayed until the weight gain was 5%, followed by drying for 10 minutes. Gum arabic, gelatin, and glycerin were then added to deionized water and stirred for 30 minutes to obtain a second coating layer. The mass ratio of gum arabic, gelatin, glycerin, and deionized water was 3:2:1:

94. Under the same conditions, the weight gain was 3%. After coating, the mixture was allowed to cool naturally and then packaged in vacuum aluminum foil bags. It was then allowed to stand at 25°C for 48 hours to obtain the halophilic microbial agent masterbatch.

4. The multifunctional soil conditioner according to claim 1, characterized in that, The preparation method of the sword bean powder extract includes the following steps: C1: Select high-quality white sword beans, grind them in a universal grinder, pass them through a 60-mesh sieve to obtain coarse sword bean powder, place the coarse sword bean powder in an extractor, add petroleum ether, and reflux in a 70℃ water bath for 4 hours to defatt it. After defatting, place the sword bean powder in a fume hood to evaporate and remove residual petroleum ether, and then transfer it to a 40℃ vacuum drying oven to dry for 6 hours to obtain defatted sword bean powder, which is then sealed and stored for later use. C2: Add β-mercaptoethanol, sodium azide, and polyvinylpyrrolidone to phosphate buffer, wherein the mass ratio of β-mercaptoethanol, sodium azide, polyvinylpyrrolidone, and phosphate buffer is 0.1:0.05:0.5:

100. Stir and mix for 30 min, then filter through a 0.45 μm filter membrane and pre-cool at 4 °C for 30 min to obtain pre-cooled buffer. C3: Add pre-cooled buffer and defatted kaempferia powder to the reaction vessel, wherein the mass ratio of pre-cooled buffer to defatted kaempferia powder is 8:

1. Set the reaction vessel speed to 300 rpm and stir for 15 min. After mixing, transfer to a low-temperature constant temperature shaking incubator, set the temperature to 4℃ and the speed to 150 rpm, and shake for 8 h. After shaking extraction, transfer to a 4℃ cold storage and let stand for 4 h to obtain the extract. C4: Filter the extract coarsely through double-layer gauze, collect the filtrate, transfer the filtrate to a refrigerated centrifuge, set the speed to 8000 rpm and the temperature to 4℃, centrifuge for 15 min, collect the supernatant, add fresh phosphate buffer to the precipitate to resuspend, centrifuge again under the same conditions, the mass ratio of precipitate to fresh phosphate buffer is 1:5, combine the supernatants from the two centrifuges to obtain the crude extract of sword bean; C5: Slowly add finely ground ammonium sulfate powder to the crude extract of sword bean while stirring until the ammonium sulfate saturation reaches 30%. After standing at 4℃ for 2 hours, centrifuge at 8000 rpm for 15 minutes, discard the precipitate, collect the supernatant, and continue to add ammonium sulfate until the saturation reaches 60%. Let stand at 4℃ overnight, and centrifuge at 10000 rpm for 20 minutes the next day to collect the precipitate. Dissolve the precipitate in 0.05 mol / L Tris-HCl buffer solution with pH 7.0 to obtain the concentrated urease solution. C6: The concentrated urease solution was placed into a regenerated cellulose dialysis bag with a molecular weight cutoff of 10 kDa. Before use, the dialysis bag was pretreated by boiling with 2% sodium bicarbonate and 1 mmol / L EDTA for 10 min. The dialysis bag was placed in 50 volumes of 0.01 mol / L phosphate buffer at pH 7.0 and dialyzed magnetically at 4°C for 24 h. The external dialysis solution was replaced every 6 h. After dialysis, the liquid in the dialysis bag was collected to obtain the desalted urease solution. C7: Load the desalted urease solution onto a DEAE-Sepharose Fast Flow anion exchange chromatography column. Equilibrate the column with 0.02 mol / L, pH 7.0 Tris-HCl buffer. After loading, elute unbound proteins with the same buffer at a flow rate of 1 ml / min and collect the elution peak. Then, elute with a linear gradient of 0-0.5 mol / L NaCl at a flow rate of 1 ml / min, collecting 5 ml from each tube. Measure the absorbance at 280 nm and the urease activity in each tube, collect the activity peak, combine the activity peaks, and concentrate them to 1 / 5 of the original volume using an ultrafiltration centrifuge tube with a molecular weight cutoff of 30 kDa to obtain a partially purified urease solution. C8: A portion of the purified urease solution was loaded onto a Sephadex G-200 gel filtration chromatography column and eluted with 0.05 mol / L phosphate buffer at pH 7.0 at a flow rate of 0.3 ml / min. 2 ml of solution was collected from each tube, and the urease activity of each tube was measured. The activity peak was collected to obtain a high-purity urease solution. C9: Add trehalose, mannitol, and EDTA to the high-purity urease solution and stir until homogeneous. The mass ratio of the high-purity urease solution, trehalose, mannitol, and EDTA is 100:2:1:0.

5. Dispense the solution into sterile freeze-drying bottles, 10 ml per bottle, and pre-freeze at -80℃ for 4 hours. After pre-freezing, transfer the solution to a freeze dryer, set the cold trap temperature to -50℃, the vacuum degree to 10 Pa, and freeze-dry for 24 hours. Immediately after freeze-drying, seal the solution with nitrogen to obtain freeze-dried sword bean powder extract. Store at 4℃. When using, reconstitute the freeze-dried powder with 10 ml of deionized water per gram to obtain the sword bean powder extract.

5. The method for preparing a multifunctional soil conditioner according to claim 1, characterized in that, Includes the following steps: S1: The halophilic microbial agent masterbatch is put into a fluidized bed granulator. The fluidized bed inlet air temperature is set to 40℃ and the outlet air temperature to 30℃. The fluidization air volume is adjusted to make the masterbatch in a good fluidized state. The modified nano gypsum core powder and sword bean powder extract are mixed and added to the reaction vessel. Then, polyethylene glycol 2000 and deionized water are added to adjust the solid content to 15%. The mixture is stirred evenly to obtain the first spraying liquid. S2: Dissolve urea and calcium chloride in deionized water to prepare a second spraying solution with a total concentration of 0.5 mol / L. Under fluidized conditions, first spray the first spraying solution onto the halophilic microbial agent masterbatch at a rate of 5 ml / min for 10 min, then spray the second spraying solution at a rate of 3 ml / min. Repeat the spraying of the first and second spraying solutions 3-5 times. After each spraying, dry for 3 min. The drying conditions are: inlet air temperature 45℃, outlet air temperature 35℃, and fluidized air velocity adjusted to 1.5 m / s. Stop spraying when the particle size reaches 1.2-1.5 mm to obtain the primary conditioner. S3: Dissolve alkyl glycosides in deionized water to prepare a 1% solution. Spray the solution onto the surface of the primary conditioner at a rate of 2 ml / min. After complete spraying, dry for 30 min. The drying conditions are: inlet air temperature 50℃, outlet air temperature 40℃, and fluidization velocity adjusted to 1.2 m / s. After drying, sieve and collect particles between 20-40 mesh to obtain a multifunctional soil conditioner. Place it in an aluminum foil bag, seal it with nitrogen gas, and store it in a cool, dry place.

6. The multifunctional soil conditioner according to claim 3, characterized in that, The high-salt selective culture medium described in step B1 comprises 5 g / L yeast extract, 10 g / L peptone, 100 g / L NaCl, 10 g / L Na2CO3, and 20 g / L agar, with a pH of 9.

0.

7. The multifunctional soil conditioner according to claim 3, characterized in that, The fermentation medium described in step B2 comprises 20 g / L corn steep liquor, 15 g / L molasses, 10 g / L soybean meal powder, 80 g / L NaCl, 8 g / L Na2CO3, and a pH of 8.5.

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