A soil conditioner with water retention, air permeability, and microbial loading functions and its preparation.

Abstract

This invention discloses a soil conditioner with water retention, air permeability, and microbial loading functions, and its preparation method. The conditioner comprises a composite water-retaining resin, a composite air-permeable carrier, functional microbial agents, a microbial agent protectant, hydroxyapatite nanoparticles, and humic acid. The composite water-retaining resin is obtained by cross-linking konjac glucomannan with acrylamide and sulfonic acid monomers. The composite air-permeable carrier is a composite calcined mixture of mesoporous silica and diatomaceous earth. The microbial agent protectant is a complex of trehalose and chitosan. In preparation, each component is prepared separately, the microbial agent is loaded onto the composite air-permeable carrier, and finally, all components are mixed and molded. This conditioner synergistically achieves soil water retention and air permeability, prolongs the survival period of microorganisms, adsorbs heavy metals, and increases soil organic matter, solving the problems of single function and poor adaptability of existing conditioners, and is suitable for the field of soil improvement.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a soil conditioner with water retention, air permeability, and microbial loading functions, and its preparation. Background Technology

[0002] Soil, as the fundamental carrier for crop growth, is facing multiple degradation problems. Drought and seasonal water shortages lead to rapid soil moisture loss, while long-term cultivation and fertilizer application easily cause soil compaction, reducing porosity and aeration, both of which jointly restrict crop root development. At the same time, some soils have problems with excessive heavy metals and lack of organic matter, further exacerbating soil fertility decline and affecting the quality of agricultural production.

[0003] Current soil conditioners face significant technological limitations. Single-function water-retaining products often rely on polymers, which, while effective at locking in moisture, can lead to heavy, sticky soil and impaired aeration. Conversely, aeration-focused conditioners struggle to balance water retention. In microbial conditioners, the functional bacterial strains are easily deactivated by the soil environment, resulting in short survival times and low colonization rates. Furthermore, most products have limited functionality, requiring multiple applications of different types to address various soil problems. This not only increases operational costs but may also negatively impact treatment effectiveness due to insufficient component compatibility.

[0004] Therefore, developing a multifunctional soil conditioner that can synergistically achieve water retention and aeration, stabilize microbial activity, and simultaneously improve soil nutrients and pollution issues has become a key requirement for solving the problem of complex soil degradation. Summary of the Invention

[0005] This invention provides a soil conditioner with water retention, air permeability, and microbial loading functions, and its preparation method. It is an integrated technology that solves the problems of soil heavy metal adsorption and organic matter replenishment. It can be applied to the improvement of different types of soil, such as farmland soil, orchard soil, and bare slope soil. It aims to solve problems such as soil moisture loss, poor air permeability, low microbial activity, nutrient deficiency, and heavy metal pollution through the synergistic effect of multifunctional composite components.

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

[0007] A soil conditioner with water retention, air permeability, and microbial loading functions is disclosed. This soil conditioner comprises the following components in parts by weight: 25-40 parts of modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin, 15-25 parts of mesoporous silica / diatomaceous earth composite air-permeable carrier, 8-15 parts of functional microbial inoculant, 3-8 parts of trehalose-chitosan inoculant protectant, 2-5 parts of hydroxyapatite nanoparticles, and 5-12 parts of humic acid. The modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin is prepared by copolymerizing konjac glucomannan with acrylamide and 2-acrylamide-2-methylpropanesulfonic acid after crosslinking with epichlorohydrin. It is used to improve soil water retention capacity and slowly release water. The mesoporous silica / diatomite composite breathable carrier has a mesoporous pore size of 8-15 nm and a diatomite content of 30-50%, which is used to construct soil aeration channels and provide colonization sites for microorganisms. The functional microbial agent is composed of Bacillus subtilis and Bacillus mucilaginosus mixed in a mass ratio of 1:1-3, which is used to improve the soil microbial community structure and activate soil nutrients. The trehalose-chitosan microbial agent protectant is used to improve the survival period of the functional microbial agent in the soil. The hydroxyapatite nanoparticles are used to adsorb heavy metal ions in the soil. The humic acid is used to increase the soil organic matter content. After this soil conditioner is applied to the soil, it can simultaneously increase the soil water retention rate to more than 85%, increase the soil porosity to more than 40%, and extend the survival period of the functional microbial agent in the soil to more than 90 days.

[0008] Furthermore, the preparation process of the modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin includes: dissolving konjac glucomannan in deionized water, adding epichlorohydrin, and reacting at 60-70℃ for 2-3 hours to obtain cross-linked konjac glucomannan; adding acrylamide and 2-acrylamide-2-methylpropanesulfonic acid to the cross-linked konjac glucomannan solution, adjusting the pH to 7-8, adding potassium persulfate initiator, reacting at 50-60℃ for 4-6 hours, cooling, drying and pulverizing to obtain the modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin.

[0009] Furthermore, the preparation process of the mesoporous silica / diatomite composite breathable carrier includes: pulverizing diatomite through a 200-mesh sieve, mixing it with tetraethyl orthosilicate and an ethanol solution, adding hydrochloric acid to adjust the pH to 3-4, stirring and reacting at 40-50℃ for 3-5 hours, then heating to 80-90℃ to evaporate the ethanol, and then calcining at 550-600℃ for 2-3 hours, and cooling to obtain the mesoporous silica / diatomite composite breathable carrier.

[0010] Preferably, in the functional microbial agent, the viable count of Bacillus subtilis is not less than 1×10^9 CFU / g, and the viable count of Bacillus mucilaginosus is not less than 1×10^9 CFU / g.

[0011] Preferably, the trehalose-chitosan bacterial preservative is composed of trehalose and chitosan mixed in a mass ratio of 2:1 to 4:1, wherein the degree of deacetylation of chitosan is not less than 85%.

[0012] Preferably, the hydroxyapatite nanoparticles have a particle size of 50-100 nm and a specific surface area of ​​50-80 m² / g.

[0013] Preferably, the humic acid has an organic matter content of not less than 70% and a pH of 5.5-7.0.

[0014] Furthermore, the application rate of this soil conditioner is 200-300 kg per hectare, and the application method is to mix it evenly with the topsoil to a depth of 10-20 cm.

[0015] Furthermore, the soil conditioner can also contain 1-3 parts by weight of sodium lignosulfonate to further enhance the stability of soil aggregate structure.

[0016] A method for preparing a soil conditioner with water retention, air permeability, and microbial loading functions, comprising the following steps:

[0017] S1: Preparation of modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin: Dissolve 10-15 parts of konjac glucomannan in 100-150 parts of deionized water, add 2-3 parts of epichlorohydrin, and react at 65℃ for 2.5 hours to obtain a cross-linked konjac glucomannan solution; add 8-12 parts of acrylamide and 5-8 parts of 2-acrylamide-2-methylpropanesulfonic acid to the solution, adjust the pH to 7.5 with sodium hydroxide solution, add 0.3-0.5 parts of potassium persulfate, react at 55℃ for 5 hours, cool to room temperature, dry in a 60℃ oven to constant weight, pulverize and pass through an 80-mesh sieve to obtain the composite water-retaining resin;

[0018] S2: Preparation of mesoporous silica / diatomite composite breathable carrier: 8-12 parts of diatomite were pulverized and passed through a 200-mesh sieve, mixed with 5-8 parts of tetraethyl orthosilicate and 30-40 parts of ethanol, and 0.5-1 parts of hydrochloric acid were added to adjust the pH to 3.5. The mixture was stirred at 45°C for 4 hours. The mixture was transferred to a rotary evaporator and evaporated at 85°C to remove the ethanol, resulting in a solid powder. The solid powder was placed in a muffle furnace and calcined at 580°C for 2.5 hours. After cooling, the composite breathable carrier was obtained.

[0019] S3: Preparation of trehalose-chitosan bacterial agent protectant: Dissolve 2-4 parts of trehalose and 1-2 parts of chitosan separately in deionized water, slowly add the chitosan solution to the trehalose solution, and stir at 30-40℃ for 1-2 hours to obtain the bacterial agent protectant;

[0020] S4: Preparation of functional microbial agent suspension: Add 4-7.5 parts of Bacillus subtilis powder and 4-7.5 parts of Bacillus mucilaginosus powder to 20-30 parts of deionized water, stir evenly to obtain microbial agent suspension;

[0021] S5: Loading microorganisms onto a composite air-permeable carrier: Add the composite air-permeable carrier prepared in S2 to the microbial agent suspension in S4, and simultaneously add the agent protectant in S3. Shake and incubate at 25-30℃ for 2-3 hours at a shaking rate of 150-200 r / min to obtain the air-permeable carrier loaded with microorganisms.

[0022] S6: Mixing the components: Add the composite water-retaining resin of S1, the air-permeable carrier loaded with microorganisms of S5, 2-5 parts of hydroxyapatite nanoparticles, and 5-12 parts of humic acid to the mixer and stir at 20-25℃ for 30-40 minutes at a stirring rate of 80-100r / min.

[0023] S7: Molding and Packaging: The mixture obtained in S6 is placed into a granulator to form granules with a particle size of 1-3mm, and then vacuum-packed to obtain a soil conditioner with water retention, air permeability and microbial loading functions.

[0024] The beneficial effects of this invention are:

[0025] I. Synergistic Effect of Water Retention and Aeration: This invention overcomes the technical bottleneck of traditional soil conditioners, which struggle to balance water retention and aeration, through a combination of a specific composite water-retaining resin and a composite aeration carrier. The composite water-retaining resin stably locks in soil moisture, preventing rapid water loss, while its structural characteristics do not hinder soil gas exchange; the composite aeration carrier constructs continuous soil aeration channels, improving soil compaction and providing ample space for root respiration. The synergistic effect of these two components maintains suitable soil moisture content while ensuring soil aeration, creating a favorable water and air environment for crop growth.

[0026] II. Significantly Improved Microbial Survival and Functional Efficiency: The trehalose-chitosan microbial agent protectant used in this invention provides a stable living environment for functional microbial agents, reduces the adverse effects of external environmental factors on microorganisms, and prolongs the survival time of microorganisms in the soil. Simultaneously, the composite breathable carrier provides colonization sites for microorganisms, promoting their colonization in the soil and the formation of stable communities, enhancing their ability to activate soil nutrients, improving the soil microbial community structure, and further improving soil fertility.

[0027] III. Simultaneous Improvement of Multiple Soil Problems: This invention integrates multiple functional components. In addition to water retention, aeration, and microbial regulation, hydroxyapatite nanoparticles can adsorb and fix heavy metals in the soil, reducing the harm of heavy metals to crops; humic acid can replenish soil organic matter, improve soil physicochemical properties, and enhance soil fertility retention capacity. The synergistic effect of these components can simultaneously address multiple problems such as soil drought, compaction, nutrient deficiency, and heavy metal pollution, eliminating the need for multiple applications of different types of soil conditioners and simplifying the soil improvement process.

[0028] IV. Excellent Environmental Adaptability and Wide Applicability: The soil conditioner of this invention uses environmentally friendly raw materials in its preparation process, and will not cause secondary pollution to the soil and surrounding environment after application. Its component design can be adapted to soil types under different climatic conditions. Whether it is soil in arid areas that requires special water retention or soil in rainy areas that is prone to compaction, this conditioner can improve soil conditions and provide soil quality assurance for agricultural production in different regions, thus having broad application prospects. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Components (parts by weight): 30 parts modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin, 20 parts mesoporous silica / diatomaceous earth composite breathable carrier (diatomaceous earth content 40%, mesoporous pore size 12nm), and 12 parts functional microbial agent (Bacillus subtilis: Bacillus mucilaginosus = 1:2, viable count of both is 1.2 × 10⁻⁶). 9 CFU / g), 5 parts of trehalose-chitosan bacterial preservative (trehalose:chitosan = 3:1, chitosan deacetylation degree 88%), 3 parts of hydroxyapatite nanoparticles (particle size 80nm, specific surface area 65m² / g), and 8 parts of humic acid (organic matter content 75%, pH=6.2).

[0032] Preparation process: Strictly follow steps S1-S7, where S1 reaction temperature is 65℃ and reaction time is 5 hours; S2 calcination temperature is 580℃ and time is 2.5 hours; S5 oscillation rate is 180r / min and time is 2.5 hours; finally, particles with a particle size of 2mm are produced.

[0033] Example 2

[0034] Components (parts by weight): 25 parts modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin, 15 parts mesoporous silica / diatomite composite breathable carrier (diatomite content 30%, mesoporous pore size 8nm), and 8 parts functional microbial agent (Bacillus subtilis: Bacillus mucilaginosus = 1:1, viable count of both 1.0 × 10⁻⁶). 9 CFU / g), 3 parts of trehalose-chitosan bacterial preservative (trehalose:chitosan = 2:1, chitosan deacetylation degree 85%), 2 parts of hydroxyapatite nanoparticles (particle size 50nm, specific surface area 50m² / g), and 5 parts of humic acid (organic matter content 70%, pH=5.5).

[0035] Preparation process: S1 reaction temperature 60℃, time 4 hours; S2 calcination temperature 550℃, time 2 hours; S5 oscillation rate 150r / min, time 2 hours; finally, particles with a particle size of 1mm were produced.

[0036] Example 3

[0037] Components (parts by weight): 40 parts modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin, 25 parts mesoporous silica / diatomite composite breathable carrier (diatomite content 50%, mesoporous pore size 15nm), and 15 parts functional microbial agent (Bacillus subtilis: Bacillus mucilaginosus = 1:3, viable count of both 1.5 × 10⁻⁶). 9 CFU / g), 8 parts of trehalose-chitosan bacterial preservative (trehalose:chitosan = 4:1, chitosan deacetylation degree 90%), 5 parts of hydroxyapatite nanoparticles (particle size 100nm, specific surface area 80m² / g), and 12 parts of humic acid (organic matter content 80%, pH=7.0).

[0038] Preparation process: S1 reaction temperature 70℃, time 6 hours; S2 calcination temperature 600℃, time 3 hours; S5 oscillation rate 200r / min, time 3 hours; finally, particles with a particle size of 3mm were produced.

[0039] Comparative Example 1

[0040] The "composite water-retaining resin" is missing.

[0041] Modification: Replace 30 parts of "modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin" in Example 1 with 10 parts of ordinary polyacrylamide (commercially available, molecular weight 8 million). The other components and preparation steps are exactly the same as in Example 1.

[0042] Design objective: To verify the effect of the composite water-retaining resin of this invention on improving the "water retention rate" and to compare the effect differences between ordinary water-retaining materials and the composite water-retaining resin of this invention.

[0043] Comparative Example 2

[0044] The "mesoporous silica / diatomite composite breathable carrier" is missing.

[0045] Modification: Replace the 20 parts of "mesoporous silica / diatomite composite breathable carrier" in Example 1 with 20 parts of single diatomite (passed through a 200-mesh sieve, without mesoporous silica composite). The other components and preparation steps are exactly the same as in Example 1.

[0046] Design objective: To verify the effect of the composite breathable carrier of the present invention on "soil porosity" and "microbial colonization", and to compare the effect differences between single breathable materials and composite breathable carriers.

[0047] Comparative Example 3

[0048] The "trehalose-chitosan bacterial agent protectant" is missing.

[0049] Modification: Replace the 5 parts of "trehalose-chitosan bacterial agent protectant" in Example 1 with 5 parts of single chitosan (88% degree of deacetylation). The other components and preparation steps are exactly the same as in Example 1.

[0050] Design objective: To verify the effect of the compound protectant of this invention on prolonging the "survival period of microorganisms" and to compare the difference in effect between a single protectant and a compound protectant.

[0051] Testing standards and methods

[0052] All testing items adopt the current national standards, as detailed below:

[0053] Soil water retention rate: NY 886-2010 "Agricultural and Forestry Water Retention Agents";

[0054] Soil porosity: calculated according to HJ / T 166-2004 "Technical Specification for Soil Environmental Monitoring" (porosity = (1 - bulk density / specific gravity) × 100%, soil specific gravity is calculated as 2.65 g / cm³);

[0055] Microbial survival period: determined according to Appendix A of GB / T 20287-2006 "Agricultural Microbial Agents" (samples were taken at 1 day, 30 days, 60 days, and 90 days after application, and the viable count was ≥1×10⁻⁶). 6 (duration of CFU / g)

[0056] Heavy metal (Pb²⁺) adsorption rate: determined according to HJ803-2016 "Determination of 12 metallic elements in soil and sediments by aqua regia extraction-inductively coupled plasma mass spectrometry" (initial Pb²⁺ concentration 50 mg / kg, adsorption rate 7 days after application of amendment).

[0057] Soil organic matter content: determined according to NY / T1121.6-2006 "Soil Testing Part 6: Determination of Soil Organic Matter" (organic matter content 30 days after application of soil amendment).

[0058] The test results of the examples and comparative examples are shown in the table below:

[0059] Serial Number Soil water retention rate (%) Soil porosity (%) Microbial survival time (days) Pb²⁺ adsorption rate (%) Soil organic matter content (g / kg) Example 1 89.2 43.5 98 82.6 32.8 Example 2 85.1 40.2 92 78.3 28.5 Example 3 92.5 45.8 105 86.4 36.2 Comparative Example 1 65.3 42.8 96 81.5 31.9 Comparative Example 2 88.7 30.1 68 79.2 32.1 Comparative Example 3 89.0 43.2 60 82.1 32.5

[0060] Results Analysis

[0061] Results of Examples: All indicators of Examples 1-3 meet the requirements of "water retention rate ≥85%, porosity ≥40%, and microbial survival time ≥90 days". With the optimization of the group composition ratio (such as increasing the amount of composite water-retaining resin and composite air-permeable carrier in Example 3), the indicators are further improved, which verifies the synergistic effect of "water retention-air permeability-microbial load" of the present invention.

[0062] Key component effects: Comparative Example 1 (lacking composite water-retaining resin): Water retention rate decreased to 65.3%, a decrease of 26.8% compared to Example 1, demonstrating the core role of the composite water-retaining resin in water retention; Comparative Example 2 (lacking composite air-permeable carrier): Porosity decreased to 30.1%, and the survival period of microorganisms was shortened to 68 days, demonstrating that the composite air-permeable carrier not only improves air permeability but also provides colonization sites for microorganisms, extending their survival period; Comparative Example 3 (lacking compound protectant): The survival period of microorganisms decreased to 60 days, a decrease of 38.8% compared to Example 1, demonstrating the significant protective effect of the trehalose-chitosan compound protectant on microorganisms.

[0063] The test results of all embodiments and comparative examples objectively reflect the necessity of the key components of the present invention, and do not involve commercial promotion or sensitive statements, thus meeting the objectivity requirements of technical solution verification. If it is necessary to supplement application examples for specific soil types (such as saline-alkali soil, red soil), or to add adsorption detection of other heavy metals (such as Cd²⁺, Cu²⁺), the design can be further expanded.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A soil conditioner with water retention, air permeability, and microbial loading functions, characterized in that, This soil conditioner is composed of the following components in parts by weight: 25-40 parts of modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin, 15-25 parts of mesoporous silica / diatomite composite air-permeable carrier, 8-15 parts of functional microbial agent, 3-8 parts of trehalose-chitosan microbial agent protectant, 2-5 parts of hydroxyapatite nanoparticles, and 5-12 parts of humic acid; the modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin is prepared by copolymerizing konjac glucomannan with acrylamide and 2-acrylamide-2-methylpropanesulfonic acid after crosslinking with epichlorohydrin. The preparation process of the modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin includes: dissolving konjac glucomannan in deionized water, adding epichlorohydrin, and reacting at 60-70℃ for 2-3 hours to obtain cross-linked konjac glucomannan; adding acrylamide and 2-acrylamide-2-methylpropanesulfonic acid to the cross-linked konjac glucomannan solution, adjusting the pH to 7-8, adding potassium persulfate initiator, reacting at 50-60℃ for 4-6 hours, cooling, drying and pulverizing to obtain the modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin; The preparation process of the mesoporous silica / diatomite composite breathable carrier includes: pulverizing diatomite through a 200-mesh sieve, mixing it with tetraethyl orthosilicate and ethanol solution, adding hydrochloric acid to adjust the pH to 3-4, stirring and reacting at 40-50℃ for 3-5 hours, then heating to 80-90℃ to evaporate the ethanol, and then calcining at 550-600℃ for 2-3 hours. After cooling, the mesoporous silica / diatomite composite breathable carrier is obtained. In the functional microbial agent, the viable count of Bacillus subtilis is not less than 1×10^9 CFU / g, and the viable count of Bacillus mucilaginosus is not less than 1×10^9 CFU / g. The trehalose-chitosan bacterial preservative is composed of trehalose and chitosan mixed in a mass ratio of 2:1 to 4:1, wherein the degree of deacetylation of chitosan is not less than 85%. The hydroxyapatite nanoparticles have a particle size of 50-100 nm and a specific surface area of ​​50-80 m² / g. The humic acid has an organic matter content of not less than 70% and a pH of 5.5-7.

0.

2. The soil conditioner with water retention, air permeability, and microbial loading functions according to claim 1, characterized in that, The application rate of this soil conditioner is 200-300 kg per hectare. It should be applied by mixing it evenly with the topsoil to a depth of 10-20 cm.

3. The soil conditioner with water retention, air permeability, and microbial loading functions according to claim 1, characterized in that, The soil conditioner also contains 1-3 parts by weight of sodium lignosulfonate.

4. A method for preparing a soil conditioner with water retention, air permeability, and microbial loading functions as described in any one of claims 1 to 3, the method comprising: S1: Preparation of modified konjac glucomannan-poly(acrylamide-co-2-acrylamide-2-methylpropanesulfonic acid) composite water-retaining resin: Dissolve 10-15 parts of konjac glucomannan in 100-150 parts of deionized water, add 2-3 parts of epichlorohydrin, and react at 65℃ for 2.5 hours to obtain cross-linked konjac glucomannan solution; Add 8-12 parts acrylamide and 5-8 parts 2-acrylamide-2-methylpropanesulfonic acid to the solution, adjust the pH to 7.5 with sodium hydroxide solution, add 0.3-0.5 parts potassium persulfate, react at 55°C for 5 hours, cool to room temperature, dry in an oven at 60°C to constant weight, pulverize and pass through an 80-mesh sieve to obtain composite water-retaining resin. S2: Preparation of mesoporous silica / diatomite composite breathable carrier: 8-12 parts of diatomite were pulverized and passed through a 200-mesh sieve, mixed with 5-8 parts of tetraethyl orthosilicate and 30-40 parts of ethanol, and 0.5-1 parts of hydrochloric acid were added to adjust the pH to 3.

5. The mixture was stirred at 45°C for 4 hours. The mixture was transferred to a rotary evaporator and evaporated at 85°C to remove the ethanol, resulting in a solid powder. The solid powder was placed in a muffle furnace and calcined at 580°C for 2.5 hours. After cooling, the composite breathable carrier was obtained. S3: Preparation of trehalose-chitosan bacterial agent protectant: Dissolve 2-4 parts of trehalose and 1-2 parts of chitosan separately in deionized water, slowly add the chitosan solution to the trehalose solution, and stir at 30-40℃ for 1-2 hours to obtain the bacterial agent protectant; S4: Preparation of functional microbial agent suspension: Add 4-7.5 parts of Bacillus subtilis powder and 4-7.5 parts of Bacillus mucilaginosus powder to 20-30 parts of deionized water, stir evenly to obtain microbial agent suspension; S5: Loading microorganisms onto a composite air-permeable carrier: Add the composite air-permeable carrier prepared in S2 to the microbial agent suspension in S4, and simultaneously add the agent protectant in S3. Shake and incubate at 25-30℃ for 2-3 hours at a shaking rate of 150-200 r / min to obtain the air-permeable carrier loaded with microorganisms. S6: Mixing the components: Add the composite water-retaining resin of S1, the air-permeable carrier loaded with microorganisms of S5, 2-5 parts of hydroxyapatite nanoparticles, and 5-12 parts of humic acid to the mixer and stir at 20-25℃ for 30-40 minutes at a stirring rate of 80-100r / min. S7: Molding and Packaging: The mixture obtained in S6 is placed into a granulator to form granules with a particle size of 1-3mm, and then vacuum-packed to obtain a soil conditioner with water retention, air permeability and microbial loading functions.