An acidic soil conditioner and a method of making same

Abstract

The present application relates to the technical field of agricultural fertilizer, in particular to an acid soil conditioner and a preparation method thereof. In order to solve the problem of soil acidification, the present application prepares an acid soil conditioner for improving acid soil. In order to avoid the problem that traditional acid soil conditioners such as quicklime and slaked lime are not conducive to controlling pH value and are lost too quickly, the acid soil conditioner prepared by the present application is modified by adopting a multiple mode of layered double hydroxide intercalation + acid-responsive gel plugging + microbial loading, thereby giving it the function of pH value response release, effectively avoiding the problem of soil alkalization caused by excessive addition of soil conditioner.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer technology, specifically to an acidic soil conditioner and its preparation method. Background Technology

[0002] Soil acidification is a prominent soil degradation problem caused by the long-term excessive application of chemical fertilizers in agricultural production. Its harm permeates the entire chain of soil quality, crop growth, agricultural efficiency, and the ecological environment. Soil acidification directly damages soil aggregate structure, leading to soil compaction, a significant decrease in aeration, water retention, and fertilizer retention capacity, resulting in a year-on-year decline in soil organic matter content and a continuous decline in soil fertility. Simultaneously, an acidified environment exacerbates the fixation and loss of micronutrients in the soil, preventing their effective absorption by crops and causing a severe imbalance in soil nutrient structure, further reducing soil quality. Furthermore, soil acidification disrupts the growth balance of soil microbial communities, leading to reduced activity of beneficial microorganisms and the proliferation of harmful microorganisms, which is detrimental to soil nutrient transformation and crop root development, directly causing crop growth degradation. These harms ultimately lead to a year-on-year increase in agricultural input costs, a continuously declining input-output ratio, a significant decrease in crop yields, a marked reduction in agricultural product quality, and ecological damage, severely restricting the sustainable development of agriculture. Therefore, it is urgent to develop effective soil acidification remediation technologies to address these technical challenges. Summary of the Invention

[0003] The purpose of this invention is to provide an acidic soil conditioner and its preparation method to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing an acidic soil conditioner, comprising the following steps: S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture during the dropwise addition. Once the pH value reaches the standard, stop adding acetic acid solution and continue stirring and mixing for 30-60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; The surface-neutralized hydrotalcite was added to the intercalation modification solution, stirred and mixed evenly, heated to 55~65℃, stirred and dispersed for 4~8h, centrifuged to separate the precipitate, washed with deionized water until the pH of the washing solution was 7.5~8, and then vacuum dried to constant weight to obtain the intercalated modified hydrotalcite. S3. Add sodium alginate to deionized water, heat to 40~45℃, stir until completely dissolved, and then cool the solution to 20~30℃ to obtain sodium alginate gel for later use. After mixing Bacillus, Actinomycetes, and sucrose, the mixture was added to sodium alginate gel and stirred for 30-60 minutes. Then, intercalated modified hydrotalcite was added and stirred for another 1-2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. Add acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add sodium hydroxide, stir to neutralize, add acrylamide and chitosan, stir evenly, add acetic acid solution to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add N,N'-methylenebisacrylamide and citric acid, dissolve, add microbially loaded hydrotalcite, stir to mix evenly, slowly add ammonium persulfate and sodium bisulfite, after the addition is complete, raise the temperature to 35~40℃, react for 1.5~2 hours, stop heating, freeze dry, crush the obtained product and pass it through a 100-mesh sieve to obtain an acidic soil conditioner.

[0005] Furthermore, the hydrotalcite has a particle size of 0.1~5μm.

[0006] Furthermore, in step S1, the pH standard is that the pH of the mixed solution is stable within the range of 7.5 to 8.

[0007] Furthermore, in step S2, the sodium hydroxide concentration in the intercalation modification solution is 0.3~0.5 mol / L, and the sodium carbonate concentration is 0.08~0.16 mol / L.

[0008] Furthermore, in step S2, the mass ratio of surface neutralizing hydrotalcite to intercalation modification liquid is (1~2):10.

[0009] Furthermore, in step S3, the amounts of each component added are 200-300 parts of deionized water, 15-20 parts of sodium alginate, 2.5-5 parts of Bacillus, 2-4 parts of actinomycetes, 2-4 parts of sucrose, and 100-120 parts of intercalated modified hydrotalcite.

[0010] Furthermore, in step S4, the amounts of each component added are 15-18 parts acrylic acid, 7.5-9 parts sodium hydroxide, 10-11 parts acrylamide, 10-11 parts chitosan, 0.08-0.1 parts N,N'-methylenebisacrylamide, 4-5 parts citric acid, 150-200 parts microbially loaded hydrotalcite, 0.15-0.18 parts ammonium persulfate, and 0.1-0.12 parts sodium bisulfite.

[0011] Furthermore, an acidic soil conditioner is prepared by the above method.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are: To address the problem of soil acidification, this invention prepares an acidified soil conditioner for improving acidic soils. To avoid the problems of traditional acidified soil conditioners, such as quicklime and hydrated lime, which are not conducive to pH control and are lost too quickly, the acidified soil conditioner prepared in this invention is modified through multiple methods, including layered double hydroxide intercalation, acid-responsive gel blocking, and microbial loading, thereby giving it the function of pH-responsive release. This invention first uses hydrotalcite as a raw material. Hydrotalcite is a magnesium-aluminum layered double hydroxide compound. Its layers are composed of Mg²⁺, Al³⁺ and hydroxyl groups. Alkali ions such as OH⁻ and CO3²⁻ can be stably intercalated between the layers to form a stable structure of "layer-interlayer alkaline ions". It can effectively load alkaline ions while playing a slow release role, which can avoid the drastic fluctuation of soil pH caused by the one-time release of alkaline ions. Furthermore, based on this, the present invention uses hydrotalcite to load beneficial bacteria commonly found in normal cultivated land, such as Bacillus and Actinomycetes. This allows the soil conditioner prepared by the present invention to quickly improve the soil microbial environment after improving the soil pH value, thereby assisting crop growth. In order to avoid excessive alkalinity affecting the activity of the bacteria during the processing, the present invention has limited the steps in the preparation process. First, sodium alginate is used to coat the bacteria, and the hydrotalcite is neutralized to avoid excessive alkalinity affecting the activity of the bacteria. Building upon this foundation, the present invention further utilizes chitosan as a macromolecular backbone, and synthesizes it in situ with acrylic acid and acrylamide on the surface of hydrotalcite to create a water-absorbing coating layer with pH-responsive properties. Under acidic conditions, the amino groups of chitosan are protonated and the acrylic acid groups are deprotonated, resulting in a significant increase in electrostatic repulsion of the molecular chains and an increase in the intermolecular gaps. This facilitates the release of internal alkaline ions and water absorption. Under neutral and weakly alkaline conditions, the amino groups are deprotonated, while the carboxyl groups are neutralized, leading to hydrophobic association and chain entanglement of the molecular chains. This reduces the release of internal alkaline ions and effectively avoids the soil alkalization problem caused by excessive addition of soil conditioners. Detailed Implementation

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] The hydrotalcite powder used in the embodiments and comparative examples of this application has a particle size of 0.4~5μm; Example 1. A method for preparing an acidic soil conditioner, comprising the following steps: S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; In the intercalation modification solution, the sodium hydroxide concentration is 0.3 mol / L and the sodium carbonate concentration is 0.08 mol / L. By weight, 2 parts of surface-neutralized hydrotalcite were added to 10 parts of intercalation modification solution. After stirring and mixing evenly, the mixture was heated to 60°C and stirred and dispersed for 8 hours. After centrifugation to separate the precipitate, the precipitate was washed with deionized water until the pH of the washing solution was 7.5. The solution was then vacuum dried to constant weight to obtain intercalation modified hydrotalcite. S3. By weight, add 15 parts sodium alginate to 300 parts deionized water, heat to 45°C, stir until completely dissolved, and then cool the solution to 30°C to obtain sodium alginate gel for later use. 2.5 parts of Bacillus, 2.5 parts of Actinomycetes, and 2 parts of sucrose were mixed and added to sodium alginate gel. After stirring for 60 minutes, 100 parts of intercalated modified hydrotalcite were added and stirred for another 2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. By weight, add 15 parts of acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add 7.5 parts of sodium hydroxide, stir to neutralize, add 10 parts of acrylamide and 10 parts of chitosan, stir evenly, add acetic acid solution dropwise to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add 0.08 parts of N,N'-methylenebisacrylamide and 4 parts of citric acid, dissolve, add 150 parts of microbially loaded hydrotalcite, stir to mix evenly, slowly add 0.15 parts of ammonium persulfate and 0.1 parts of sodium bisulfite, after the addition is complete, heat to 40℃, react for 2 hours, stop heating, freeze dry, crush the obtained product and pass through a 100-mesh sieve to obtain an acidic soil conditioner.

[0015] Example 2. A method for preparing an acidic soil conditioner, comprising the following steps: Compared with Example 1, this example increases the concentration of various solutes in the intercalation modification solution in step S2; S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; In the intercalation modification solution, the sodium hydroxide concentration is 0.5 mol / L and the sodium carbonate concentration is 0.16 mol / L. By weight, 2 parts of surface-neutralized hydrotalcite were added to 10 parts of intercalation modification solution. After stirring and mixing evenly, the mixture was heated to 60°C and stirred and dispersed for 8 hours. After centrifugation to separate the precipitate, the precipitate was washed with deionized water until the pH of the washing solution was 7.5. The solution was then vacuum dried to constant weight to obtain intercalation modified hydrotalcite. S3. By weight, add 15 parts sodium alginate to 300 parts deionized water, heat to 45°C, stir until completely dissolved, and then cool the solution to 30°C to obtain sodium alginate gel for later use. 2.5 parts of Bacillus, 2.5 parts of Actinomycetes, and 2 parts of sucrose were mixed and added to sodium alginate gel. After stirring for 60 minutes, 100 parts of intercalated modified hydrotalcite were added and stirred for another 2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. By weight, add 15 parts of acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add 7.5 parts of sodium hydroxide, stir to neutralize, add 10 parts of acrylamide and 10 parts of chitosan, stir evenly, add acetic acid solution dropwise to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add 0.08 parts of N,N'-methylenebisacrylamide and 4 parts of citric acid, dissolve, add 150 parts of microbially loaded hydrotalcite, stir to mix evenly, slowly add 0.15 parts of ammonium persulfate and 0.1 parts of sodium bisulfite, after the addition is complete, heat to 40℃, react for 2 hours, stop heating, freeze dry, crush the obtained product and pass through a 100-mesh sieve to obtain an acidic soil conditioner.

[0016] Example 3. A method for preparing an acidic soil conditioner, comprising the following steps: Compared with Example 1, this example increases the amount of Actinomycetes and Bacillus added in step S3; S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; In the intercalation modification solution, the sodium hydroxide concentration is 0.3 mol / L and the sodium carbonate concentration is 0.08 mol / L. By weight, 2 parts of surface-neutralized hydrotalcite were added to 10 parts of intercalation modification solution. After stirring and mixing evenly, the mixture was heated to 60°C and stirred and dispersed for 8 hours. After centrifugation to separate the precipitate, the precipitate was washed with deionized water until the pH of the washing solution was 7.5. The solution was then vacuum dried to constant weight to obtain intercalation modified hydrotalcite. S3. By weight, add 15 parts sodium alginate to 300 parts deionized water, heat to 45°C, stir until completely dissolved, and then cool the solution to 30°C to obtain sodium alginate gel for later use. Five parts of Bacillus, four parts of Actinomycetes, and two parts of sucrose were mixed and added to sodium alginate gel. After stirring for 60 minutes, 100 parts of intercalated modified hydrotalcite were added and stirred for another 2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. By weight, add 15 parts of acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add 7.5 parts of sodium hydroxide, stir to neutralize, add 10 parts of acrylamide and 10 parts of chitosan, stir evenly, add acetic acid solution dropwise to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add 0.08 parts of N,N'-methylenebisacrylamide and 4 parts of citric acid, dissolve, add 150 parts of microbially loaded hydrotalcite, stir to mix evenly, slowly add 0.15 parts of ammonium persulfate and 0.1 parts of sodium bisulfite, after the addition is complete, heat to 40℃, react for 2 hours, stop heating, freeze dry, crush the obtained product and pass through a 100-mesh sieve to obtain an acidic soil conditioner.

[0017] Example 4. A method for preparing an acidic soil conditioner, comprising the following steps: S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; In the intercalation modification solution, the sodium hydroxide concentration is 0.5 mol / L and the sodium carbonate concentration is 0.16 mol / L. By weight, 1 part of surface neutralizing hydrotalcite was added to 10 parts of intercalation modification solution. After stirring and mixing evenly, the mixture was heated to 60°C and stirred and dispersed for 8 hours. After centrifugation to separate the precipitate, it was washed with deionized water until the pH of the washing solution was 7.5. Then, it was vacuum dried to constant weight to obtain intercalation modified hydrotalcite. S3. By weight, add 20 parts of sodium alginate to 300 parts of deionized water, heat to 45°C, stir until completely dissolved, and then cool the solution to 30°C to obtain sodium alginate gel for later use. Five parts of Bacillus, four parts of Actinomycetes, and four parts of sucrose were mixed and added to sodium alginate gel. After stirring for 60 minutes, 120 parts of intercalated modified hydrotalcite were added and stirred for another 2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. By weight, add 18 parts of acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add 9 parts of sodium hydroxide, stir to neutralize, add 11 parts of acrylamide and 11 parts of chitosan, stir evenly, add acetic acid solution to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add 0.1 parts of N,N'-methylenebisacrylamide and 5 parts of citric acid, dissolve, add 200 parts of microbially loaded hydrotalcite, stir to mix evenly, slowly add 0.18 parts of ammonium persulfate and 0.12 parts of sodium bisulfite, after the addition is complete, heat to 40℃, react for 2 hours, stop heating, freeze dry, crush the obtained product and pass through a 100-mesh sieve to obtain an acidic soil conditioner.

[0018] Comparative Example 1. A method for preparing an acidic soil conditioner, comprising the following steps: Compared with Example 1, this comparative example did not prepare intercalated modified hydrotalcite, but only used surface-neutralized hydrotalcite to participate in the S3 step reaction; S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S3. By weight, add 15 parts sodium alginate to 300 parts deionized water, heat to 45°C, stir until completely dissolved, and then cool the solution to 30°C to obtain sodium alginate gel for later use. 2.5 parts of Bacillus, 2.5 parts of Actinomycetes, and 2 parts of sucrose were mixed and added to sodium alginate gel. After stirring for 60 minutes, 100 parts of surface neutralizing hydrotalcite were added and the mixture was stirred for another 2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. By weight, add 15 parts of acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add 7.5 parts of sodium hydroxide, stir to neutralize, add 10 parts of acrylamide and 10 parts of chitosan, stir evenly, add acetic acid solution dropwise to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add 0.08 parts of N,N'-methylenebisacrylamide and 4 parts of citric acid, dissolve, add 150 parts of microbially loaded hydrotalcite, stir to mix evenly, slowly add 0.15 parts of ammonium persulfate and 0.1 parts of sodium bisulfite, after the addition is complete, heat to 40℃, react for 2 hours, stop heating, freeze dry, crush the obtained product and pass through a 100-mesh sieve to obtain an acidic soil conditioner.

[0019] Comparative Example 2. A method for preparing an acidic soil conditioner, comprising the following steps: Compared with Example 1, this comparative example did not prepare microbial-loaded hydrotalcite, but directly used intercalated modified hydrotalcite for step S4 treatment; S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; In the intercalation modification solution, the sodium hydroxide concentration is 0.3 mol / L and the sodium carbonate concentration is 0.08 mol / L. By weight, 2 parts of surface-neutralized hydrotalcite were added to 10 parts of intercalation modification solution. After stirring and mixing evenly, the mixture was heated to 60°C and stirred and dispersed for 8 hours. After centrifugation to separate the precipitate, the precipitate was washed with deionized water until the pH of the washing solution was 7.5. The solution was then vacuum dried to constant weight to obtain intercalation modified hydrotalcite. S4. By weight, add 15 parts of acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add 7.5 parts of sodium hydroxide, stir to neutralize, add 10 parts of acrylamide and 10 parts of chitosan, stir evenly, add acetic acid solution to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add 0.08 parts of N,N'-methylenebisacrylamide and 4 parts of citric acid, dissolve, add 150 parts of intercalated modified hydrotalcite, stir to mix evenly, slowly add 0.15 parts of ammonium persulfate and 0.1 parts of sodium bisulfite, after the addition is complete, heat to 40℃, react for 2 hours, stop heating, freeze dry, crush the obtained product and pass through a 100-mesh sieve to obtain an acidic soil conditioner.

[0020] Comparative Example 3. A method for preparing an acidic soil conditioner, comprising the following steps: Compared with Example 1, this comparative example only prepared intercalated modified hydrotalcite as an acid soil conditioner; S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture. Once the pH value stabilizes in the range of 7.5 to 7.8, stop adding acetic acid solution and continue stirring and mixing for 60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; In the intercalation modification solution, the sodium hydroxide concentration is 0.3 mol / L and the sodium carbonate concentration is 0.08 mol / L. By weight, 2 parts of surface-neutralized hydrotalcite were added to 10 parts of intercalation modification solution. After stirring and mixing evenly, the mixture was heated to 60°C and stirred and dispersed for 8 hours. After centrifugation to separate the precipitate, the precipitate was washed with deionized water until the pH of the washing solution was 7.5. The solution was then vacuum dried to constant weight to obtain intercalation modified hydrotalcite. S3. By weight, add 15 parts sodium alginate to 300 parts deionized water, heat to 45°C, stir until completely dissolved, and then cool the solution to 30°C to obtain sodium alginate gel for later use. Mix 2.5 parts Bacillus, 2.5 parts Actinomycetes, and 2 parts sucrose, then add the mixture to sodium alginate gel and stir for 60 minutes. Then add 100 parts intercalated modified hydrotalcite and continue stirring for 2 hours. After centrifugation to separate the precipitate, freeze-dry to obtain an acidic soil conditioner.

[0021] Detection: The acid soil conditioners prepared in Examples 1-4 and Comparative Examples 1-3 were added to the acid soil at an addition rate of 300 kg / mu, and the soil pH value was tested at 0h, 1h, 24h, 15d and 30d according to the NY / T 1121-2008 standard. The acid soil conditioners prepared in Examples 1-4 and Comparative Examples 1-3 were added to acid soil at an addition rate of 300 kg / mu, respectively, as experimental plots. Wheat was planted in each plot, and a plot without acid soil conditioner was set up as a control example. The yield growth rate was calculated. The calculation formula is as follows:

[0022] The test results are shown in Table 1 below; Table 1. Example 1 5.36 5.46 6.07 6.42 6.51 16.2 Example 2 5.36 5.47 6.18 6.52 6.59 17.1 Example 3 5.36 5.46 6.06 6.40 6.51 17.4 Example 4 5.36 5.47 6.16 6.50 6.57 18.6 Comparative Example 1 5.36 5.38 5.36 5.31 5.24 1.4 Comparative Example 2 5.36 5.49 6.11 6.43 6.50 8.2 Comparative Example 3 5.36 5.62 6.24 7.46 6.83 12.1 Comparison Example 5.36 5.36 5.36 5.36 5.36 0 Example 1 and Comparative Example 3 were added to acidic soil at a rate of 500 kg / mu, respectively. The acidic soil was tested at 1 day, 15 days and 30 days according to the NY / T 1121-2008 standard. The test results are shown in Table 2 below. Table 2. Example 1 5.52 6.42 6.74 Comparative Example 3 6.01 7.01 7.71 It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0023] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an acidic soil conditioner, characterized in that, Includes the following steps: S1. Add hydrotalcite to deionized water, stir and disperse to prepare a suspension, then add acetic acid solution dropwise, stirring continuously and monitoring the pH value of the mixture during the dropwise addition. Once the pH value reaches the standard, stop adding acetic acid solution and continue stirring and mixing for 30-60 minutes. Then, centrifuge to separate the precipitate and vacuum dry to constant weight to obtain surface-neutralized hydrotalcite. S2. Add sodium hydroxide and sodium carbonate to deionized water, stir and mix evenly to prepare the intercalation modification solution; The surface-neutralized hydrotalcite was added to the intercalation modification solution, stirred and mixed evenly, heated to 55~65℃, stirred and dispersed for 4~8h, centrifuged to separate the precipitate, washed with deionized water until the pH of the washing solution was 7.5~8, and then vacuum dried to constant weight to obtain the intercalated modified hydrotalcite. S3. Add sodium alginate to deionized water, heat to 40~45℃, stir until completely dissolved, and then cool the solution to 20~30℃ to obtain sodium alginate gel for later use. After mixing Bacillus, Actinomycetes, and sucrose, the mixture was added to sodium alginate gel and stirred for 30-60 minutes. Then, intercalated modified hydrotalcite was added and stirred for another 1-2 hours. After centrifugation to separate the precipitate, the mixture was freeze-dried to obtain microbial-loaded hydrotalcite. S4. Add acrylic acid to deionized water, cool to a constant temperature in an ice-water bath, add sodium hydroxide, stir to neutralize, add acrylamide and chitosan, stir evenly, add acetic acid solution to adjust the pH of the reaction system to 5.0~5.5, stir to mix evenly, add N,N'-methylenebisacrylamide and citric acid, dissolve, add microbially loaded hydrotalcite, stir to mix evenly, slowly add ammonium persulfate and sodium bisulfite, after the addition is complete, raise the temperature to 35~40℃, react for 1.5~2 hours, stop heating, freeze dry, crush the obtained product and pass it through a 100-mesh sieve to obtain an acidic soil conditioner.

2. The method for preparing an acidic soil conditioner according to claim 1, characterized in that: The hydrotalcite has a particle size of 0.1~5μm.

3. The method for preparing an acidic soil conditioner according to claim 1, characterized in that: In step S1, the pH standard is that the pH of the mixed solution is stable within the range of 7.5 to 8.

4. The method for preparing an acidic soil conditioner according to claim 1, characterized in that: In step S2, the sodium hydroxide concentration in the intercalation modification solution is 0.3~0.5 mol / L, and the sodium carbonate concentration is 0.08~0.16 mol / L.

5. The method for preparing an acidic soil conditioner according to claim 1, characterized in that: In step S2, the mass ratio of surface neutralizing hydrotalcite to intercalation modification liquid is (1~2):

10.

6. A method for preparing an acidic soil conditioner according to claim 1, characterized in that: In step S3, the amounts of each component added are 200-300 parts of deionized water, 15-20 parts of sodium alginate, 2.5-5 parts of Bacillus, 2-4 parts of actinomycetes, 2-4 parts of sucrose, and 100-120 parts of intercalated modified hydrotalcite.

7. A method for preparing an acidic soil conditioner according to claim 1, characterized in that: In step S4, the amounts of each component added are 15-18 parts acrylic acid, 7.5-9 parts sodium hydroxide, 10-11 parts acrylamide, 10-11 parts chitosan, 0.08-0.1 parts N,N'-methylenebisacrylamide, 4-5 parts citric acid, 150-200 parts microbially loaded hydrotalcite, 0.15-0.18 parts ammonium persulfate, and 0.1-0.12 parts sodium bisulfite.

8. An acidic soil conditioner prepared by the preparation method according to any one of claims 1 to 7.

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