An acid soil long-acting modifier, a preparation method and application thereof

Abstract

The application provides a long-acting acid soil modifier, which comprises 30-50 parts of organic aluminum ion complex component A, 25-45 parts of base supplement component B, 15-25 parts of porous adsorption component C and 5-15 parts of microbial synergistic component D; the organic aluminum ion complex component A comprises a complexing agent and a modifier; the application further provides a preparation method of the long-acting acid soil modifier, which comprises the following steps: raw material pretreatment, mixing, granulation and low-temperature drying; and the application further provides an application of the long-acting acid soil modifier; through the triple mechanism of complexing aluminum ions, supplementing base ions and improving buffer performance, the application realizes the mild, persistent and ecological repair of acid soil; the addition of the modifier in the organic aluminum ion complex component A greatly reduces the liquid soluble sulfate concentration, avoids the accumulation of a large amount of free sulfate in a short time, generates hydroxyl ions to assist acid adjustment, and has double synergies, so that the rising amplitude of soil EC is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of acid soil improvement technology, and in particular to a long-lasting acid soil conditioner, its preparation method, and its application. Background Technology

[0002] Soil acidification is a global problem limiting sustainable agricultural development. Traditional methods for improving acidic soils mainly rely on the application of quicklime, hydrated lime, or calcium magnesium phosphate fertilizers. While these methods can quickly neutralize active acid in the soil, they have several drawbacks: first, they can easily cause a "sudden stop" effect, leading to the destruction of soil aggregate structure and compaction; second, large short-term pH fluctuations can easily cause "root burn" to crop roots; and third, the effect is short-lived, requiring annual application, and cannot fundamentally restore the soil's acid-base buffering capacity.

[0003] In recent years, the use of organic materials to improve acidified soils has received widespread attention. Existing technologies disclose various methods for preparing conditioners using biochar, humic acid, or chitosan oligosaccharides. For example, Chinese invention patent CN121379605A proposes a composite conditioner for improving acidic soils and its preparation method. This composite conditioner comprises the following raw materials in parts by weight: 3050 parts alkaline organic fertilizer, 2035 parts modified biochar, 1020 parts silicon-calcium-potassium-magnesium ore powder, 515 parts composite microbial inoculant, and 25 parts complexing synergist. The composite conditioner for improving acidic soils and its preparation method provided by this invention have the advantages of gently and persistently adjusting acidity, simultaneously and efficiently increasing organic matter, and creating an optimal living environment for functional microorganisms.

[0004] However, biochar or humic acid alone has limited passivation capabilities for active aluminum in highly acidic soils, and its ability to increase soil basic ion content is relatively slow. For crops requiring rapid elimination of aluminum toxicity, there is still room for improvement in its effectiveness. Furthermore, current methods mostly use substances like calcium lignosulfonate to achieve aluminum ion complexation and solidification, but these introduce new problems: calcium lignosulfonate contains 8%-10% sulfur, and long-term, continuous application as a single agent can lead to the continuous accumulation of sulfate; the byproduct contains soluble sodium salts, and excessive application can increase soil electrical conductivity; and in anaerobic conditions in paddy fields, sulfate is reduced to hydrogen sulfide, damaging the root system. Therefore, a better soil conditioner is needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a long-lasting soil conditioner for acidic soils, its preparation method, and its application. This invention solves the problems of low efficiency in eliminating aluminum salts and the side effects of prolonged use of calcium lignosulfonate in existing technologies.

[0006] In a first aspect, the present invention provides a long-lasting soil conditioner for acidic soils, comprising the following components in parts by weight:

[0007] Organoaluminum ion complex component A: 30-50 parts;

[0008] Base supplement component B: 25-45 parts;

[0009] Porous adsorption component C: 15-25 parts;

[0010] Microbial synergist component D: 5-15 parts;

[0011] The organoaluminum ion complexing component A includes a complexing agent and a modifier, wherein the mass ratio of the complexing agent to the modifier is 1:0.1-0.15; the complexing agent includes one or more of calcium lignosulfonate, sodium lignosulfonate, or polyγ-glutamic acid calcium, and the modifier includes one or a mixture of two of basic magnesium carbonate and calcium aluminate.

[0012] Preferably, the complexing agent is alkylated with propylene oxide or ethylene oxide to form alkylated modified calcium lignosulfonate, alkylated modified sodium lignosulfonate, or alkylated modified polyγ-glutamic acid calcium.

[0013] Preferably, the base supplement component B includes one or more of fermented livestock and poultry manure, earthworm castings, or green manure.

[0014] Preferably, the porous adsorption component C includes one or more of biochar, activated carbon, or humic acid.

[0015] Preferably, the microbial synergist component D includes one or more of Bacillus mucilaginosus, Bacillus amyloliquefaciens, or actinomycetes.

[0016] Secondly, this invention proposes a method for preparing a long-lasting soil conditioner for acidic soils, comprising the following steps:

[0017] S1. Raw material pretreatment: Air-dry or low-temperature dry component B until the moisture content is below 15%, and pulverize it through a 40-mesh sieve; Component C is pulverized through a 60-80 mesh sieve.

[0018] S2. Mixing: Mix the pulverized component C and component D evenly in proportion, and let it stand for 12-24 hours to activate; put component A, pretreated component B, and the mixture of component C and component D into the mixer and mix thoroughly for 20-30 minutes.

[0019] S3. Granulation: Spray water, accounting for 15%-20% of the total weight of the material, into the mixture and granulate it in a granulator to obtain particles with a particle size of 3-5mm.

[0020] S4. Low-temperature drying: The particles obtained in step S3 are dried at a low temperature of 40-50℃ until the moisture content is less than 10%, thus obtaining the long-lasting soil conditioner granules.

[0021] Furthermore, step S1 also includes: dissolving the complexing agent in component A in anhydrous ethanol, adding propylene oxide or ethylene oxide and heating to 65°C-70°C, holding at that temperature for 2-4 hours to obtain an alkylated modified complexing agent, which is then mixed with a modifier to form an organoaluminum ion complexing component A.

[0022] Thirdly, this invention proposes the application of a long-lasting soil conditioner for acidic soils. The conditioner is used to improve acidic soils at a rate of 100-200 kg / mu, applied as a base fertilizer, and mixed evenly with the topsoil during application.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Gentle passivation to eliminate aluminum toxicity: Through the complexation of substances such as calcium lignin sulfonate in component A, active aluminum ions in the soil are directly passivated, eliminating acid damage at the source and avoiding the drastic fluctuations in soil pH and potential damage to roots caused by traditional quick-acting alkalis such as lime.

[0025] 2. Enhance base saturation and provide long-term buffering: Fermented organic fertilizers such as livestock and poultry manure are rich in base ions such as calcium and magnesium, which can effectively increase the base saturation and cation exchange capacity of the soil, enhance the soil's own buffering capacity against acidification, and achieve long-term acid suppression.

[0026] 3. Structural Improvement and Ecological Restoration: The addition of biochar or activated carbon to the porous adsorption component C improves the soil's physical structure, enhances its water and fertilizer retention capacity, and provides a favorable habitat for beneficial microorganisms. Furthermore, microbial agents can be loaded into the pores of the porous adsorption component C to form a synergistic effect, allowing them to remain in the soil for extended periods, continuously activating soil nutrients and restoring the soil's microecology.

[0027] 4. Environmentally friendly and resource-recycling: The raw materials of this invention are mainly derived from industrial and agricultural by-products (calcium lignosulfonate) and agricultural waste (straw charcoal, livestock and poultry manure), realizing the resource utilization of waste and eliminating the risk of secondary pollution.

[0028] 5. Through a triple mechanism of “complexing aluminum ions, replenishing basic ions, and enhancing buffering performance”, it achieves gentle, lasting, and ecological restoration of acidic soils.

[0029] 6. This invention also incorporates a modifier into the organoaluminum ion complex component A. The basic magnesium carbonate dissociates to release hydroxide ions, chemically neutralizing free acid in the soil. This not only rapidly neutralizes acidity and replenishes magnesium groups but also preserves the sulfonic acid chelating functional groups of the modified calcium lignin sulfonate, thus retaining its ability to passivate aluminum toxicity. Calcium aluminate dissociates into calcium and aluminate ions upon contact with water, reacting with free sulfate ions to form calcium sulfate (slightly soluble stable crystals) and aluminum hydroxide precipitates. This permanently fixes the sulfate ions in the soil, significantly reducing the concentration of soluble sulfate in the liquid phase. Simultaneously, hydroxide ions are generated to assist in acid regulation, resulting in a dual synergistic effect.

[0030] 7. This invention also involves alkylating the ortho-hydroxyl groups in the complexing agent with propylene oxide and ethylene oxide to form sterically hindered encapsulation of SO3. - The modified sulfonic acid groups slowly decompose and release sulfate ions into the soil, preventing the rapid accumulation of large amounts of free sulfate ions; simultaneously, the modified sulfonic acid groups react with Ca... 2+ With improved stability, it is less likely to dissociate into soluble sulfates, and the increase in soil EC is greatly reduced. Detailed Implementation

[0031] The technical solutions of the present invention will be further described below with reference to the embodiments.

[0032] Example 1:

[0033] This embodiment of a long-lasting soil conditioner for acidic soil comprises the following components in parts by weight:

[0034] Organoaluminum ion complex component A: 30 parts;

[0035] Base supplement component B: 30 parts;

[0036] Porous adsorption component C: 25 parts;

[0037] Microbial synergist component D: 15 parts;

[0038] The organic aluminum ion complexing component A comprises a complexing agent and a modifier, with a mass ratio of complexing agent to modifier of 1:0.12; the complexing agent is alkylated modified calcium lignosulfonate. The modifier is basic magnesium carbonate. Base supplement component B is fermented livestock and poultry manure. Porous adsorption component C is biochar, obtained from crop straw or sawdust through limited oxygen pyrolysis at 350-550℃. Microbial synergistic component D is gelatinous Bacillus.

[0039] The specific preparation method of the long-lasting soil conditioner for acidic soil in this embodiment is as follows:

[0040] (1) Raw material pretreatment: air-dry or low-temperature dry component B until the moisture content is less than 15%, and pulverize it through a 40-mesh sieve; pulverize component C through a 70-mesh sieve; dissolve the complexing agent in component A in anhydrous ethanol, add propylene oxide or ethylene oxide and heat to 68°C, keep warm for 3 hours to obtain an alkylated modified complexing agent, and then mix it with the modifier to form organoaluminum ion complex component A.

[0041] (2) Mixing: Mix the pulverized component C and component D in proportion and let it stand for 18 hours to activate; put component A, pretreated component B and the mixture of component C and component D into the mixer and mix thoroughly for 25 minutes.

[0042] (3) Granulation: Water accounting for 18% of the total weight of the material is sprayed into the mixture and granulated in a granulator to obtain particles with a particle size of 4 mm.

[0043] (4) Low temperature drying: The particles obtained in step S3 are dried at 45°C until the moisture content is less than 10%, thus obtaining the long-lasting soil conditioner granules.

[0044] The acidic soil long-term conditioner of this embodiment is used to improve acidic soil. The application rate is 150 kg / mu. It is applied as a base fertilizer and should be mixed evenly with the topsoil when applied.

[0045] Example 2:

[0046] This embodiment of a long-lasting soil conditioner for acidic soil comprises the following components in parts by weight:

[0047] Organoaluminum ion complex component A: 35 parts;

[0048] Base supplement component B: 45 parts;

[0049] Porous adsorption component C: 15 parts;

[0050] Microbial synergist component D: 5 parts;

[0051] The organic aluminum ion complexing component A comprises a complexing agent and a modifier, with a mass ratio of complexing agent to modifier of 1:0.1; the complexing agent is alkylated modified sodium lignosulfonate. The modifier is calcium aluminate. Base supplement component B is earthworm castings. Porous adsorption component C is activated carbon. Microbial synergistic component D is Bacillus amyloliquefaciens.

[0052] The specific preparation method of the long-lasting soil conditioner for acidic soil in this embodiment is as follows:

[0053] (1) Raw material pretreatment: air-dry or low-temperature dry component B until the moisture content is less than 15%, and pulverize it through a 40-mesh sieve; pulverize component C through a 60-mesh sieve; dissolve the complexing agent in component A in anhydrous ethanol, add propylene oxide or ethylene oxide and heat to 65°C, keep warm for 2 hours to obtain an alkylated modified complexing agent, and then mix it with the modifier to form organoaluminum ion complex component A.

[0054] (2) Mixing: Mix the pulverized component C and component D evenly in proportion and let it stand for 12 hours to activate; put component A, pretreated component B and the mixture of component C and component D into the mixer and mix thoroughly for 20 minutes.

[0055] (3) Granulation: Water accounting for 15% of the total weight of the material is sprayed into the mixture and granulated in a granulator to obtain particles with a particle size of 3mm.

[0056] (4) Low temperature drying: The particles obtained in step S3 are dried at 40°C until the moisture content is less than 10%, thus obtaining the long-lasting soil conditioner granules.

[0057] The acidic soil long-term conditioner of this embodiment is used to improve acidic soil. The application rate is 100 kg / mu. It is applied as a base fertilizer and should be mixed evenly with the topsoil when applied.

[0058] Example 3:

[0059] This embodiment of a long-lasting soil conditioner for acidic soil comprises the following components in parts by weight:

[0060] Organoaluminum ion complex component A: 50 parts;

[0061] Base supplement component B: 25 parts;

[0062] Porous adsorption component C: 17 parts;

[0063] Microbial synergist component D: 8 parts;

[0064] The organic aluminum ion complexing component A comprises a complexing agent and a modifier, with a mass ratio of complexing agent to modifier of 1:0.15; the complexing agent is alkylated modified polyγ-glutamic acid calcium. The modifier is a mixture of basic magnesium carbonate and calcium aluminate in equal proportions. Base supplement component B is a mixture of fermented livestock and poultry manure, earthworm castings, and green manure in equal proportions. Porous adsorption component C is a mixture of biochar, activated carbon, and humic acid in equal proportions. Microbial synergistic component D is a mixture of Bacillus mucilaginosus, Bacillus amyloliquefaciens, and actinomycetes in equal proportions.

[0065] The specific preparation method of the long-lasting soil conditioner for acidic soil in this embodiment is as follows:

[0066] (1) Raw material pretreatment: air-dry or low-temperature dry component B until the moisture content is less than 15%, and pulverize it through a 40-mesh sieve; pulverize component C through an 80-mesh sieve; dissolve the complexing agent in component A in anhydrous ethanol, add propylene oxide or ethylene oxide and heat to 70°C, keep warm for 4 hours to obtain an alkylated modified complexing agent, and then mix it with the modifier to form organoaluminum ion complex component A.

[0067] (2) Mixing: Mix the pulverized component C and component D evenly in proportion and let it stand for 24 hours to activate; put component A, pretreated component B and the mixture of component C and component D into the mixer and mix thoroughly for 30 minutes.

[0068] (3) Granulation: Water accounting for 20% of the total weight of the material is sprayed into the mixture and granulated in a granulator to obtain particles with a particle size of 5mm.

[0069] (4) Low temperature drying: The particles obtained in step S3 are dried at 50°C until the moisture content is less than 10%, thus obtaining the long-lasting soil conditioner granules.

[0070] The acidic soil long-term conditioner of this embodiment is used to improve acidic soil. The application rate is 200 kg / mu. It is applied as a base fertilizer and should be mixed evenly with the topsoil when applied.

[0071] Comparative Example 1:

[0072] The rest of the components in this embodiment are the same as in Example 1, except that: the organoaluminum ion complexing component A only includes a complexing agent, and the complexing agent is calcium lignosulfonate.

[0073] Comparative Example 2:

[0074] The rest of this embodiment is the same as in Example 1, except that: the organoaluminum ion complexing component A includes a complexing agent and a modifier, wherein the complexing agent is calcium lignosulfonate and the modifier is basic magnesium carbonate.

[0075] Comparative Example 3:

[0076] The rest of the components in this embodiment are the same as in Example 1, except that: the organoaluminum ion complexing component A only includes a complexing agent, wherein the complexing agent is alkylated modified calcium lignosulfonate.

[0077] The parameters of the products from Examples 1-3 and Comparative Examples 1-3 were compared, and the results are shown in Table 1:

[0078]

[0079] Table 1

[0080] As shown in Table 1, the product prepared in the embodiments of the present invention resulted in a significantly higher soil pH after 90 days, and a higher soil exchange capacity (H+). + The reduction rate is also better, indicating that it can improve soil acidification faster and more efficiently. In addition, its reduction rate of soil soluble SO4 is also better. 2- A lower content indicates less residual sulfuric acid in the soil, making it less prone to sulfate accumulation and further reduction to hydrogen sulfide, which could damage the roots. Simultaneously, the lower 180-day soil pH drop of this invention indicates a slower reacidification rate, demonstrating its long-term stability.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A long-lasting soil conditioner for acidic soils, characterized in that, Includes the following components by weight: Organoaluminum ion complex component A: 30-50 parts; Base supplement component B: 25-45 parts; Porous adsorption component C: 15-25 parts; Microbial synergist component D: 5-15 parts; The organoaluminum ion complexing component A includes a complexing agent and a modifier, wherein the mass ratio of the complexing agent to the modifier is 1:0.1-0.15; the complexing agent includes one or more of calcium lignosulfonate, sodium lignosulfonate, or polyγ-glutamic acid calcium, and the modifier includes one or a mixture of two of basic magnesium carbonate and calcium aluminate.

2. The long-lasting soil conditioner for acidic soil as described in claim 1, characterized in that: The complexing agent is formed by alkylating hydroxyl groups with propylene oxide or ethylene oxide to form alkylated modified calcium lignosulfonate, alkylated modified sodium lignosulfonate, or alkylated modified polyγ-glutamic acid calcium.

3. The long-lasting soil conditioner for acidic soil as described in claim 1, characterized in that: The base supplement component B includes one or more combinations of fermented livestock and poultry manure, earthworm castings, or green manure.

4. The long-lasting soil conditioner for acidic soil as described in claim 1, characterized in that: The porous adsorption component C includes one or more of biochar, activated carbon, or humic acid.

5. The long-lasting soil conditioner for acidic soil as described in claim 1, characterized in that: The microbial synergist component D includes one or more of Bacillus mucilaginosus, Bacillus amyloliquefaciens, or actinomycetes.

6. A method for preparing a long-lasting soil conditioner for acidic soil as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Raw material pretreatment: Air-dry or low-temperature dry component B until the moisture content is below 15%, and pulverize it through a 40-mesh sieve; Component C is pulverized through a 60-80 mesh sieve. S2. Mixing: Mix the pulverized component C and component D evenly in proportion, and let it stand for 12-24 hours to activate; put component A, pretreated component B, and the mixture of component C and component D into the mixer and mix thoroughly for 20-30 minutes. S3. Granulation: Spray water, accounting for 15%-20% of the total weight of the material, into the mixture and granulate it in a granulator to obtain particles with a particle size of 3-5mm. S4. Low-temperature drying: The particles obtained in step S3 are dried at a low temperature of 40-50℃ until the moisture content is less than 10%, thus obtaining the long-lasting soil conditioner granules.

7. The preparation method of a long-lasting soil conditioner for acidic soil as described in claim 6, characterized in that, Step S1 further includes: dissolving the complexing agent in component A in anhydrous ethanol, adding propylene oxide or ethylene oxide and heating to 65℃-70℃, keeping it at that temperature for 2-4 hours to obtain an alkylated modified complexing agent, which is then mixed with a modifier to form an organoaluminum ion complexing component A.

8. The application of a long-lasting soil conditioner for acidic soil as described in any one of claims 1-5, characterized in that: The soil conditioner is used to improve acidic soil at a rate of 100-200 kg / mu as a base fertilizer, and should be mixed evenly with the topsoil during application.

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