Preparation method and application of acidic soil structure modifier

Abstract

The application discloses a preparation method and application of an acidic soil structure modifier. The method comprises the following steps: crushing rape straw, mixing the crushed rape straw with cow dung, and obtaining first earthworm compost material through aerobic composting; mixing sieved fly ash with the first earthworm compost material, performing earthworm composting, collecting the product after the earthworm passes through the anus, and obtaining earthworm manure carbonization precursors; performing carbonization treatment on the earthworm manure carbonization precursors, obtaining earthworm manure porous aggregates after cooling, mixing the earthworm manure porous aggregates with composite functional bacteria liquid, and sequentially performing culture and air drying to obtain carbonized earthworm manure loaded with functional microorganisms; obtaining second earthworm compost material through aerobic composting of the cow dung, uniformly mixing the carbonized earthworm manure loaded with functional microorganisms with the second earthworm compost material, performing earthworm composting, and collecting the product after the earthworm passes through the anus, so that the acidic soil structure modifier is obtained. The product prepared by the method has the triple effects of "physical skeleton support + cation bridging + biological cementing substance generation", can promote soil particle cementation, and has a better soil structure improvement effect.

Description

Technical Field

[0001] This invention relates to the field of soil conditioning technology, specifically to a method for preparing and applying an acidic soil structure improver. Background Technology

[0002] Soil acidification leads to the leaching of cementing substances, clay particles, and humus, reducing organic matter content and disrupting water-stable soil aggregates. This results in soil compaction, poor aeration and permeability, and negatively impacts crop growth. Therefore, improving the aggregate structure of acidic soils is crucial for enhancing soil quality.

[0003] The formation and stability of soil aggregates are easily influenced by factors such as soil organic matter, microorganisms, plant roots, and fertilization and tillage practices. Among these, organic matter is the main cementing substance in the aggregate formation process, having a positive effect on soil aggregate stability and being a key influencing factor. Soil microorganisms are the most active biological factor in aggregate formation, mainly promoting soil particle aggregation and influencing aggregate turnover through decomposition of organic matter and physical entanglement. The application of organic materials such as livestock and poultry manure, rich in organic matter and microorganisms, is considered an effective measure to improve soil aggregates. The polysaccharides, proteins, and organic acids and humic substances produced by microbial decomposition in organic materials can act as organic cementing agents, cementing soil particles into micro-aggregates, which further aggregate into larger aggregates, thereby improving aggregate stability.

[0004] Although the role of organic materials in improving soil physicochemical properties, promoting aggregate formation, and stabilizing soil has been proven, their practical application in acidic soils is often less effective. This is because the strongly acidic environment of acidic soils (pH < 5.5) significantly inhibits the activity of microorganisms (such as bacteria, fungi, and actinomycetes), limiting the rate of organic matter decomposition. Furthermore, long-term acidification leads to the decomposition of base cations (Ca... 2+ Mg 2+ Large amounts of leaching (etc.) occur, and the soil colloid surface is covered with excessive hydrogen ions (H+, etc.). + ) and aluminum ions (Al 3+ The presence of cations also weakens the role of cation bridges in promoting the stability of soil aggregates by binding organic materials and inorganic particles. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing and applying an acidic soil structure modifier. The acidic soil structure modifier prepared by the method of this invention can significantly promote the formation of large aggregates in the soil, improve soil physical properties, and cultivate a favorable soil structure after application.

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

[0007] This invention provides a method for preparing an acidic soil structure conditioner, comprising the following steps:

[0008] (1) Mix fly ash and water, let stand, collect the lower sediment, dry and sieve;

[0009] (2) After crushing the rapeseed straw, mix it with cow dung and compost it aerobically to obtain the first earthworm compost material;

[0010] (3) Mix the sieved fly ash from step (1) with the first earthworm compost material, perform earthworm composting, collect the products after the earthworms have finished digesting, and obtain the precursor of earthworm castings carbonization.

[0011] (4) Carbonize the earthworm castings carbonization precursor and cool it to obtain porous earthworm castings aggregate.

[0012] (5) Mix the porous earthworm castings with the compound functional bacterial solution, and then culture and air dry them in sequence to obtain carbonized earthworm castings loaded with functional microorganisms.

[0013] (6) After aerobic composting of cow manure, a second earthworm compost material is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost material for earthworm composting. The products after the earthworms have finished digesting are collected to obtain an acidic soil structure improver.

[0014] Furthermore, in step (2), the mass ratio of rapeseed straw to cow dung is 1:1~2;

[0015] In step (3), the mass ratio of fly ash to the first earthworm compost material is 1:5~10;

[0016] The earthworm species used for the vermicompost is Eisenia fetida, and the inoculation quantity is 5000-10000 earthworms / m². 3 materials.

[0017] Furthermore, the mass ratio of the fly ash to the first earthworm compost is 1:7;

[0018] The earthworm inoculation rate was 8000 earthworms / m². 3 materials.

[0019] Furthermore, in step (4), the carbonization process is carried out under nitrogen protection and consists of two stages:

[0020] Heating stage: The heating rate is 10~15℃ / min

[0021] Carbonization stage: carbonization temperature is 300~400℃, carbonization time is 25~30min.

[0022] Furthermore, in the carbonization process, the heating rate is 15°C / min.

[0023] The carbonization temperature was 350℃ and the carbonization time was 30 minutes.

[0024] Furthermore, in step (5), the solid-liquid ratio of the earthworm castings porous aggregate and the composite functional bacterial solution is 5:1~2 kg / L;

[0025] Composite functional bacterial solution includes Rhizobium sp. , Bacillus subtilis , Trichoderma harzianum , Streptomyces sp. In the compound functional bacterial solution, Rhizobium sp. , Bacillus subtilis , Trichoderma harzianum , Streptomyces sp. The ratio of viable bacteria per unit volume is 1:1:1:1, and the total effective bacteria content in the compound functional bacterial solution is not less than 10. 6 CFU / ml;

[0026] The culture time is 5-10 days.

[0027] Furthermore, the solid-liquid ratio of the earthworm castings porous aggregate and the composite functional bacterial solution is 5:2 kg / L;

[0028] The culture time was 5 days.

[0029] Furthermore, in step (6), the mass ratio of the carbonized earthworm castings loaded with functional microorganisms to the second earthworm compost material is 1:1~2, and the earthworm species used in the earthworm compost is Eisenia fetida, with an inoculation amount of 10,000-20,000 earthworms / m³. 3 materials.

[0030] The present invention also provides an acidic soil structure modifier prepared by the preparation method described above.

[0031] The present invention also provides an application of the aforementioned acidic soil structure modifier in improving the structure of acidic soil.

[0032] The beneficial effects of this invention are:

[0033] 1. The acidic soil structure improver prepared by this invention can significantly improve soil aggregate structure and increase soil fertility after application, and has the characteristics of long-lasting and stable effect.

[0034] 2. Compared with ordinary organic materials, the product prepared by this invention promotes soil particle cohesion and enhances aggregate stability through a triple effect of "physical framework support + cation bridging + bio-cementing substance generation," resulting in better soil structure improvement. The product prepared by this invention has a rich pore structure (micropores, mesopores, and macropores). Macropores (pore size > 50 nm) act as "core nodes," mechanically interlocking with soil clay and silt particles to form aggregates; mesopores (pore size 2-50 nm) and macropores provide habitats for microorganisms, secreting extracellular polymers and hyphae to form aggregates; micropores (pore size < 2 nm) provide soil basic cation adsorption sites, and fly ash replenishes the calcium lost from the soil. 2+ Ions enhance the "cation bridging" effect.

[0035] 3. Compared with the inhibition of microbial activity in acidic soil after the application of ordinary organic materials, the product prepared by this invention can effectively ensure the activity of microorganisms after entering acidic soil, and give full play to the function of microorganisms in the formation of soil aggregates. In this invention, rapeseed straw and fly ash make the product slightly alkaline. The high lignin content in rapeseed straw gives the product strong resistance to pyrolysis and collapse. In addition, the high-temperature sintering of fly ash precipitates crystals and creates pores, providing a suitable habitat for functional microorganisms in acidic soil. This invention uses secondary earthworm digestion through carbonized earthworm castings to encapsulate porous aggregates loaded with functional bacteria into organic matter that has been partially degraded by earthworms, providing abundant and readily available carbon and nitrogen sources for functional microorganisms and improving their survival rate in acidic soil.

[0036] 4. This invention, while preparing an acidic soil structure improver, also realizes the high-value utilization of solid waste resources such as fly ash, rapeseed straw, and cow dung. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the preparation method of an acidic soil structure improver. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can understand it.

[0039] The strains used in the following examples are described below:

[0040] Rhizobium sp. Source: China Agricultural Microbial Culture Collection Center, strain number ACCC19962; website:

[0041] http: / / www.accc.org.cn / Column.asp?Column_ID=34929&Model=product_detail&P_ID=10209229;

[0042] Bacillus subtilis Source: China Agricultural Microbial Culture Collection Center, strain number ACCC19373; website:

[0043] http: / / www.accc.org.cn / Column.asp?Column_ID=34929&Model=product_detail&P_ID=10208812;

[0044] Trichoderma harzianum Source: China Agricultural Microbial Culture Collection Center, strain number ACCC 31884; website:

[0045] http: / / www.accc.org.cn / Column.asp?Column_ID=34929&Model=product_detail&P_ID=10211283;

[0046] Streptomyces sp. Source: China Agricultural Microbial Culture Collection Center, strain number ACCC41939, website:

[0047] http: / / www.accc.org.cn / Column.asp?Column_ID=34929&Model=product_detail&P_ID=10216153.

[0048] Example 1

[0049] Preparation method of acidic soil structure improver 1

[0050] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0051] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:1, then perform aerobic composting to obtain the first earthworm compost material.

[0052] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:7, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0053] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0054] 5. Mix the porous earthworm castings with the compound functional microbial solution at a solid-liquid ratio of 5:2 kg / L until homogeneous. Adjust the moisture content to 60%, incubate for 5 days, and then air-dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms. The compound functional microbial solution contains... Rhizobium sp. , Bacillus subtilis , Trichoderma harzianum , Streptomyces sp. In the compound functional bacterial solution, Rhizobium sp. , Bacillus subtilis , Trichoderma harzianum , Streptomyces sp. The ratio of viable bacteria per unit volume is 1:1:1:1, and the total effective bacteria content in the compound functional bacterial solution is not less than 10. 6 CFU / ml.

[0055] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:1. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain acidic soil structure improver 1.

[0056] Example 2

[0057] Preparation method of acidic soil structure improver 2

[0058] 1. Mix fly ash and water at a solid-liquid ratio of 1:10 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0059] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:1, then perform aerobic composting to obtain the first earthworm compost material.

[0060] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:8, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0061] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 10°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0062] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0063] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:1. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain acidic soil conditioner 2.

[0064] Example 3

[0065] Preparation method of acidic soil structure improver 3

[0066] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0067] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0068] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:8, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0069] 4. The earthworm casting carbonization precursor obtained in step 3 is heated to 300℃ at a rate of 10℃ / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm casting aggregate.

[0070] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 10 days, and air-dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0071] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:1. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain acidic soil structure improver 3.

[0072] Example 4

[0073] Preparation method of acidic soil structure improver 4

[0074] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0075] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2, then perform aerobic composting to obtain the first earthworm compost material.

[0076] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:10, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0077] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 10°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0078] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0079] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain acidic soil conditioner 4.

[0080] Comparative Example 1

[0081] Preparation method 1 of soil conditioner (excessive fly ash dosage)

[0082] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0083] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2, then perform aerobic composting to obtain the first earthworm compost material.

[0084] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a 1:1 mass ratio, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0085] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 300℃ at a rate of 15℃ / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0086] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0087] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:1. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain a soil conditioner 1.

[0088] Comparative Example 2

[0089] Method 2 for preparing soil conditioner (excessive carbonization and temperature rise)

[0090] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0091] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0092] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:5, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0093] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350℃ at a rate of 35℃ / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0094] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0095] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain a soil conditioner.

[0096] Comparative Example 3

[0097] Preparation method 3 for soil conditioner (carbonization temperature too high)

[0098] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0099] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0100] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:5, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0101] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 700℃ at a rate of 15℃ / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0102] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0103] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain a soil conditioner.

[0104] Comparative Example 4

[0105] Method 4 for preparing soil conditioner (without giving microbial colonization time)

[0106] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0107] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2, then perform aerobic composting to obtain the first earthworm compost material.

[0108] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:5-10, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0109] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0110] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 0 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0111] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain a soil conditioner.

[0112] Comparative Example 5

[0113] Method 5 for preparing soil conditioner (for cases with excessively low microbial load)

[0114] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0115] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0116] 3. The dried and sieved fly ash from step 1 is mixed with the first earthworm compost material obtained in step 2 at a mass ratio of 1:10. Eisenia fetida is then inoculated for earthworm composting at a density of 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0117] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0118] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 20:1 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0119] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished eating to obtain a soil conditioner.

[0120] Comparative Example 6

[0121] Preparation method 6 for soil conditioner (excessive use of carbonized vermicompost loaded with functional microorganisms)

[0122] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0123] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0124] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:5, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0125] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0126] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0127] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 5:1. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 per m³. 3 Materials. Collecting the products left after earthworms have finished digesting their food yields a soil conditioner.

[0128] Comparative Example 7

[0129] Preparation method 7 for soil conditioner (the amount of carbonized vermicompost loaded with functional microorganisms is too low)

[0130] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0131] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0132] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:8, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0133] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0134] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0135] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost at a mass ratio of 1:10. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain a soil conditioner.

[0136] Comparative Example 8

[0137] Preparation method 8 for soil conditioner (without earthworms undergoing secondary digestion)

[0138] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0139] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0140] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:10, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0141] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0142] 5. Mix the porous earthworm castings with the composite functional bacterial solution from Example 1 at a solid-liquid ratio of 5:2 kg / L, adjust the moisture content to 60%, incubate for 5 days, and air dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms.

[0143] 6. After aerobic composting of cow manure, a second earthworm compost material is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost material at a mass ratio of 1:2 to obtain a soil conditioner 8.

[0144] Comparative Example 9

[0145] Preparation method 9 for soil conditioner (without earthworm castings carbonization)

[0146] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0147] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0148] 3. Mix the dried and sieved fly ash from step 1, the first earthworm compost material obtained in step 2, and the compound functional bacterial solution from Example 1 at a solid-liquid ratio of 1:5:2 kg / L. Inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 15,000 earthworms / m². 3 The material is obtained by collecting the products left after earthworms have finished digesting their food, which is a soil conditioner.

[0149] Comparative Example 10

[0150] Preparation method 10 for soil conditioner (without microbial load)

[0151] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0152] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0153] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:10, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0154] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0155] 5. After aerobic composting of cow manure, a second earthworm compost is obtained. The porous aggregate of earthworm castings is mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetida is then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished eating to obtain a soil conditioner 10.

[0156] Comparative Example 11

[0157] Preparation method 11 for soil conditioners (different microbial species)

[0158] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0159] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0160] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:10, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0161] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0162] 5. Mix the porous earthworm castings with the bacterial solution at a solid-liquid ratio of 5:2 kg / L until homogeneous. Adjust the moisture content to 60%, incubate for 5 days, and then air-dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms. The bacterial solution contains... Rhizobium sp. The total effective bacteria content in the bacterial solution is not less than 10. 6 CFU / ml.

[0163] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. The carbonized earthworm castings loaded with functional microorganisms from step 5 are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetida is then inoculated for earthworm composting at an inoculation rate of 15,000 earthworms / m². 3 Materials. Collect the products left after earthworms have finished eating to obtain a soil conditioner 11.

[0164] Comparative Example 12

[0165] Preparation methods of soil conditioners 12 (different microbial species)

[0166] 1. Mix fly ash and water at a solid-liquid ratio of 1:5 kg / L, stir for 30 minutes, let stand and separate into layers, collect the lower sediment, dry and pass through a 120-mesh sieve.

[0167] 2. Crush rapeseed straw and mix it with cow dung at a mass ratio of 1:2 to obtain the first earthworm compost material through aerobic composting.

[0168] 3. Mix the dried and sieved fly ash from step 1 with the first earthworm compost material obtained in step 2 at a mass ratio of 1:10, and inoculate with Eisenia fetida for earthworm composting. The inoculation density of Eisenia fetida is 8000 earthworms / m². 3 Materials are collected from the products of earthworms after they have finished digesting their abdomens to obtain carbonized precursors of earthworm castings.

[0169] 4. The earthworm castings carbonization precursor obtained in step 3 is heated to 350°C at a rate of 15°C / min under nitrogen protection and carbonized for 30 minutes. Then it is cooled to room temperature to obtain porous earthworm castings aggregate.

[0170] 5. Mix the porous earthworm castings with the bacterial solution at a solid-liquid ratio of 5:2 kg / L until homogeneous. Adjust the moisture content to 60%, incubate for 5 days, and then air-dry in a cool, dark place to obtain carbonized earthworm castings loaded with functional microorganisms. The bacterial solution contains... Bacillus subtilis and Trichoderma harzianum In the bacterial solution, Bacillus subtilis and Trichoderma harzianumThe ratio of viable bacteria per unit volume is 1:1, and the total effective bacteria content in the bacterial solution is not less than 10. 6 CFU / ml.

[0171] 6. After aerobic composting of cow manure, a second earthworm compost is obtained. The carbonized earthworm castings loaded with functional microorganisms from step 5 are mixed evenly with the second earthworm compost at a mass ratio of 1:2. Eisenia fetuses are then inoculated for earthworm composting at an inoculation rate of 15,000 per m³. 3 Materials. Collect the products left after earthworms have finished digesting their food to obtain a soil conditioner 12.

[0172] I. Properties Testing of Acidic Soil Structure Modifiers

[0173] The properties of acidic soil structure conditioners 1-4 from Examples 1-4 and soil conditioners 1-12 from Comparative Examples 1-12 were tested.

[0174] 1. Determine the yield of earthworm castings carbonization precursor. The determination method is to manually separate the earthworm castings from the non-castrated parts according to the material morphology and calculate the proportion of the castrated material to the total material.

[0175] 2. After obtaining the porous aggregate of earthworm castings, its pore characteristics were determined. The average pore size was determined using a surface area analyzer, the proportion of different pore sizes and porosity were determined using a scanning electron microscope (SEM), and the pH was determined using a pH meter.

[0176] 3. After obtaining carbonized earthworm castings loaded with functional microorganisms, the effective viable bacteria count was determined using the dilution plate count method.

[0177] 4. Determine the yield of acidic soil structure conditioner. The determination method is to manually separate the earthworm's ventral and non-ventral portions according to the material morphology, and calculate the proportion of ventral material to total material.

[0178] Table 1. Comparison of properties of products from key steps in the preparation of the products in the Examples and Comparative Examples.

[0179]

[0180] Note: There were no significant differences among the indicators in the examples. The values ​​of each indicator in the comparison examples are indicated by the "". "" indicates that there is a significant difference (p<0.05) between the example and the control example. The same applies below.

[0181] The results are shown in Table 1. In Examples 1-4, the yield of the vermicompost carbonization precursor was above 94%, indicating that the first vermicompost material (obtained by aerobic fermentation of cow dung and rapeseed straw) mixed with fly ash was suitable for earthworm feeding and did not have a negative impact on earthworm life activities. The average pore size in Examples 1-4 was in the range of 22-26 nm, with macropores and mesopores accounting for more than 65% and a total porosity greater than 60%, indicating that the carbonization process created a good pore structure in the vermicompost, increasing the proportion of macropores and mesopores and providing ample space for microbial colonization. The effective viable bacteria count in the carbonized vermicompost in Examples 1-4 was above 200 million / gram, indicating that the four functional bacteria successfully colonized the carbonized vermicompost. The final structure modifier yield was above 97%, indicating that the second vermicompost material (obtained by aerobic fermentation of cow dung) mixed with the carbonized vermicompost loaded with functional microorganisms was suitable for earthworm feeding and did not have a negative impact on earthworm life activities.

[0182] The yield of the vermicompost carbonization precursor in Comparative Example 1 was significantly lower than that in the Example, indicating that the first vermicompost material (obtained by aerobic fermentation of cow dung and rapeseed straw) mixed with fly ash was unsuitable for earthworms to consume, and may even have had an inhibitory effect on earthworms, making it impossible to obtain the final product. This may be attributed to the excessive amount of fly ash added, causing the mixture to deviate from the C / N ratio suitable for earthworm consumption, or it may be due to the residual harmful substances in the fly ash exceeding the earthworms' tolerance limits. Since Comparative Example 1 showed product defects in the initial stage, relevant indicators were not measured further.

[0183] Although Comparative Example 2 showed a slight increase in average pore size and the proportion of macropores + mesopores compared to the Example 2, its total porosity decreased. This is because the carbonization process in Comparative Example 2 involved excessively rapid heating, causing a large amount of volatile components to escape rapidly, resulting in a violent "burst phenomenon." This caused the micropores and mesopores that might have formed to be "collapsed," with some pores merging into macropores or even interconnected fissures, thus reducing the refinement of the pore structure. Due to the decrease in total porosity, the number of colonization sites for microorganisms was reduced, and the number of effective viable bacteria in its carbonized earthworm castings was significantly lower than in the Example 2.

[0184] The average pore size and the ratio of macropores to mesopores in Comparative Example 3 were significantly lower than those in the Example. This is because the carbonization temperature of Comparative Example 3 was too high, resulting in deep pyrolysis of lignin and the emergence of micropores as the dominant pore type. Since macropores and mesopores are the main colonization areas for microorganisms, the number of viable bacteria in the carbonized earthworm castings of Comparative Example 3 was also significantly lower than that in the Example.

[0185] The number of viable bacteria in the carbonized earthworm castings of Comparative Examples 4 and 5 was significantly lower than that in the Example. This is related to the fact that no time was allowed for microbial colonization after the porous earthworm castings aggregate was mixed with the bacterial solution and that the amount of bacterial solution mixed was too low.

[0186] The yield of the structure improver in Comparative Example 6 was less than 50%, indicating that the mixture of excessive carbonized earthworm castings and the second earthworm compost material (obtained from the aerobic fermentation of cow manure) resulted in a material with an excessively high C / N ratio, which was unsuitable for earthworms to consume.

[0187] There were no significant differences between the indicators measured in Comparative Examples 7, 11, and 12 and those in the Examples.

[0188] In Comparative Example 10, the effective live bacteria count in carbonized earthworm castings was zero because no bacterial solution was inoculated.

[0189] Due to differences in specific methods between Comparative Examples 8 and 9 and the Examples, complete index data could not be obtained (Comparative Example 8 did not involve secondary processing of earthworms, so the final yield could not be determined; Comparative Example 9 did not involve carbonization of earthworm castings, so the relevant indexes of porous earthworm castings could not be determined), but the existing index data were not significantly different from those of the Examples.

[0190] II. Comparison of the effects of acidic soil structure conditioners on improving the structure of acidic soils

[0191] 1. Based on the results in Table 1, soil conditioners 1-4 obtained in Examples 1-4 were selected for cultivation experiments, along with soil conditioners 2, 3, 4, 5, 7, 8, 9, 10, 11, and 12 obtained in Comparative Examples 2, 3, 4, 5, 7, 8, 9, 10, 11, and 12 (Comparative Examples 1 and 6 were not included in the application effect comparison due to their low yields). Furthermore, three commonly used soil conditioners (commercial conditioners 1, 2, and 3) purchased from the market were added for comparison to analyze their effects on improving the structure of acidic soils. Commercial conditioner 1 mainly consists of organic fertilizer and functional microbial agents; commercial conditioner 2 mainly consists of organic fertilizer, biochar, and functional microbial agents; and commercial conditioner 3 mainly consists of organic fertilizer and polyacrylamide.

[0192] Acidic soils were collected from Xianning, Hubei Province. After removing stones and other impurities, the soils were air-dried and sieved. The products obtained in the examples and comparative examples, as well as commercially available soil conditioners, were mixed into the soils at 10% of each. The mixed soils were adjusted to 60% field capacity and then transferred to a 25°C incubator for 60 days, during which time the soil moisture content was maintained constant by regular watering. After 60 days, soil samples were collected, air-dried naturally, and the aggregate stability was determined using a wet sieving method.

[0193] Table 2 Effects of different treatments on soil aggregate structure characteristics

[0194]

[0195] The results are shown in Table 2. The products prepared in Examples 1-4 can effectively improve the soil aggregate structure after application. After the original physical structure of the soil was completely destroyed by air drying and sieving, a large number of large aggregates were formed after 60 days of cultivation. The average mass diameter of the aggregates was above 0.6 MWD / mm, the proportion of aggregates >2mm was over 4%, the proportion of aggregates 2-0.25mm was over 40%, and the aggregation index was greater than 20%.

[0196] The average mass diameter, proportion of large aggregates, and aggregation index of Comparative Examples 2, 3, 4, 5, 7, and 10 were significantly smaller than those of the Example, indicating that their effect on improving soil physical structure was not good. This may be attributed to the fact that the number of functional bacteria loaded in Comparative Examples 2, 3, 4, 5, 7, and 10 was small or non-existent, which weakened the cementing effect of functional microorganisms on soil particles.

[0197] In Comparative Example 9, the proportion of 2-0.25mm aggregates was not significantly different from that in Example 1, but the proportion of >2mm aggregates was significantly lower. Comparative Example 9 did not carbonize the vermicompost, thus failing to provide a habitat for microorganisms. This resulted in microorganisms only being able to function for a short time after entering the acidic soil, limiting the formation of large aggregates. Furthermore, uncarbonized vermicompost lacked abundant macropores, limiting the role of "physical skeletal support" in the formation of large aggregates.

[0198] Commercial amendments 1 and 2 were significantly less effective than those in the examples, but commercial amendments 3 and comparative example 8 showed no significant difference in effectiveness compared to the examples. Furthermore, the measured indicators of the effects of comparative examples 8, 11, and 12 on the structural characteristics of soil aggregates showed no significant differences compared to the examples.

[0199] 2. Based on the results in Table 2, the long-term stability of acidic soil structure conditioners 1-4 obtained in Examples 1, 2, 3, and 4, soil conditioners 8, 11, and 12 obtained in Comparative Examples 8, 11, and 12, and commercial conditioner 3 was compared. Soils corresponding to Examples 1, 2, 3, and 4, Comparative Examples 8, 11, and 12, and commercial conditioner 3 from the above cultivation experiments were placed on filter paper and rapidly sprayed with water to quickly increase the soil moisture content and produce leachate. After being left overnight, the soil was placed in an oven for 48 hours to dry. This cycle was repeated 5 times. The distribution characteristics of water-stable aggregates in the soil were then determined using the wet sieving method.

[0200] Table 3. Effects of alternating wet and dry conditions on the distribution characteristics of water-stable aggregates in soil.

[0201]

[0202] The results are shown in Table 3. After alternating wet and dry conditions, the content of large aggregates in all soils decreased, but the decrease in the examples was significantly lower than that in Comparative Example 8 and Commercial Soil Conditioner 3. After the wet and dry alternation, the proportion of >2mm aggregates and 2-0.25mm aggregates in Comparative Example 8 was significantly lower than that in the examples. This is because Comparative Example 8 did not undergo secondary worm digestion, resulting in limited readily available nutrients in the material that could not meet the long-term needs of functional microorganisms. In addition, the lack of secondary worm digestion led to a looser encapsulation of the aggregates carrying functional microorganisms by the organic material, which could not provide a long-term habitat for the functional microorganisms. The proportions of >2mm aggregates and 2-0.25mm aggregates in Comparative Examples 11 and 12 were significantly lower than those in the examples, possibly due to the relatively simple biological groups involved, leading to a decrease in their stress resistance. After the wet and dry alternation, the proportions of >2mm aggregates and 2-0.25mm aggregates in Commercial Soil Conditioner 3 were significantly lower than those in the examples, possibly due to the loss of polyacrylamide caused by strong leaching.

[0203] The above experiments demonstrate that the acidic soil conditioner prepared by this invention can effectively improve soil structure, promote the formation of large aggregates in the soil, improve soil physical properties, and cultivate a favorable soil structure. Compared with commercially available soil conditioners, the product prepared by this invention has better soil improvement effects and better sustained effects. Comparison of the products in the comparative examples and embodiments shows that the preparation of the acidic soil structure conditioner of this invention requires adherence to all the technical requirements of this invention; any change to any technical point will lead to a decrease in product preparation efficiency or product performance.

[0204] All other parts not described in detail are existing technologies. Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing an acidic soil structure conditioner, characterized in that: Includes the following steps: (1) Mix fly ash and water, let stand, collect the lower sediment, dry and sieve; (2) After crushing the rapeseed straw, mix it with cow dung and compost it aerobically to obtain the first earthworm compost material; (3) Mix the sieved fly ash from step (1) with the first earthworm compost material, perform earthworm composting, collect the products after the earthworms have finished digesting, and obtain the precursor of earthworm castings carbonization. (4) The earthworm castings carbonization precursor is carbonized and cooled to obtain porous earthworm castings aggregate; the carbonization process is carried out under nitrogen protection and consists of two stages: Heating stage: The heating rate is 10~15℃ / min; Carbonization stage: carbonization temperature is 300~400℃, carbonization time is 25~30min; (5) Mix the porous earthworm castings with the compound functional bacterial solution, and then culture and air dry them in sequence to obtain carbonized earthworm castings loaded with functional microorganisms; the solid-liquid ratio of the porous earthworm castings and the compound functional bacterial solution is 5:1~2 kg / L. Composite functional bacterial solution includes Rhizobium sp. , Bacillus subtilis , Trichoderma harzianum , Streptomyces sp. In the compound functional bacterial solution, Rhizobium sp. , Bacillus subtilis , Trichoderma harzianum , Streptomyces sp. The ratio of viable bacteria per unit volume is 1:1:1:1, and the total effective bacteria content in the compound functional bacterial solution is not less than 10. 6 CFU / ml; The culture time is 5-10 days; (6) After aerobic composting of cow manure, a second earthworm compost material is obtained. Carbonized earthworm castings loaded with functional microorganisms are mixed evenly with the second earthworm compost material for earthworm composting. The products after the earthworms have finished digesting are collected to obtain an acidic soil structure improver.

2. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of rapeseed straw to cow dung is 1:1~2; In step (3), the mass ratio of fly ash to the first earthworm compost material is 1:5~10; The earthworm species used for the vermicompost is Eisenia fetida, and the inoculation quantity is 5000-10000 earthworms / m². 3 materials.

3. The preparation method according to claim 2, characterized in that: The mass ratio of the fly ash to the first earthworm compost is 1:7; The earthworm inoculation rate was 8000 earthworms / m². 3 materials.

4. The preparation method according to claim 1, characterized in that: In the carbonization process, the heating rate is 15℃ / min. The carbonization temperature was 350℃ and the carbonization time was 30 minutes.

5. The preparation method according to claim 1, characterized in that: The solid-liquid ratio of the porous earthworm castings aggregate and the composite functional bacterial solution is 5:2 kg / L; The culture time was 5 days.

6. The preparation method according to claim 1, characterized in that: In step (6), the mass ratio of carbonized earthworm castings loaded with functional microorganisms to the second earthworm compost material is 1:1~2. The earthworm species used in the earthworm compost is Eisenia fetida, and the earthworm inoculation amount is 10,000-20,000 earthworms / m³. 3 materials.

7. An acidic soil structure modifier prepared by the preparation method of claim 1.

8. The application of the acid soil structure modifier according to claim 7 in improving the structure of acid soil.

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