A soil conditioner and a method of making the same

Abstract

The application belongs to the technical field of agricultural soil improvement and humus resource utilization, and particularly relates to a soil conditioner and a preparation method thereof. The preparation method comprises the following steps: adding first peat, humic acid and a mixed activator into water to perform a first reaction, adding an oxidizing agent to perform a second reaction, and obtaining activated peat humic acid slurry; mixing second peat, attapulgite and a binder, then adding the activated peat humic acid slurry and a mixed aqueous solution of calcium ions and magnesium ions, and aging to obtain the soil conditioner. The preparation method of the soil conditioner provided by the application divides peat into first peat and second peat, uses a mild mixed activator to improve the activity of humic acid in the first peat, retains plant fibers and organic pore structures of the second peat, and realizes the synergy of high activity and slow release of humic acid through incomplete bridging of calcium ions and magnesium ions, so that the dual effects of rapid activation of nutrients in the early stage of soil and long-term improvement of structure, water retention and fertilizer retention are achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of agricultural soil improvement and humus resource utilization, specifically relating to a soil conditioner and its preparation method. Background Technology

[0002] Soil organic matter is a crucial material basis for maintaining arable land productivity. However, with long-term high-intensity farming and the irrational application of chemical fertilizers, some arable lands are experiencing problems such as declining organic matter content, damage to soil colloidal structure, topsoil compaction, increased bulk density, decreased porosity, reduced water and fertilizer retention capacity, and exacerbated nutrient leaching. In saline-alkali areas, phenomena such as increased exchangeable sodium content, dispersed clay particles, and enhanced rhizosphere osmotic stress may also occur.

[0003] Humic acid is a heterogeneous organic substance containing functional groups such as carboxyl, phenolic hydroxyl, carbonyl, and ether bonds. It can participate in soil cation exchange, nutrient complexation, soil particle aggregation, and rhizosphere microenvironment regulation. The effects of humic acid are closely related to its source, molecular weight distribution, functional group content, water dispersibility, and its state of existence in the soil. Peat is an organic substance formed by the incomplete decomposition and humification of plant residues under conditions of high humidity and hypoxia. Peat not only contains humic acid, fulvic acid, and humin, but also retains a certain amount of plant fiber and porous organic framework, thus possessing certain water retention, buffering, and physical support functions. Existing soil conditioners usually use raw materials such as peat, humic acid, mineral powder, animal manure, or straw, which are directly crushed and mixed or co-granulated. This method is simple, but the components are mainly physically mixed. After being applied to the soil, water-soluble humic acid is easily migrated with irrigation water, while insoluble humic acid cannot fully exert its effects in the short term.

[0004] To improve the solubility of humic acid, existing technologies use strong alkalis such as sodium hydroxide and potassium hydroxide for extraction or activation. While this can improve the water solubility of humic acid, it can also easily damage the original fiber and pore structure of peat and may lead to excessive cracking of humic acid, thus reducing its long-term aggregation effect.

[0005] Therefore, in view of the shortcomings of the existing technology of insufficient humic acid activity and difficulty in maintaining soil fertility in a long-term stable manner under the ordinary direct physical mixing process, there is an urgent need to provide a soil conditioner and its preparation method to achieve soil structure improvement and long-term enhancement of water and fertilizer retention capacity. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a soil conditioner and its preparation method. The soil conditioner provided by this invention divides peat into two parts: a first peat and a second peat. A mildly mixed activator, potassium hydroxide and potassium carbonate, is used to enhance the activity of humic acid in the first peat, while preserving the plant fiber and organic porous structure of the second peat. Furthermore, through incomplete bridging by calcium and magnesium ions, a synergistic effect of high humic acid activity and slow release is achieved, thus combining the dual effects of rapid nutrient activation in the early stages of soil improvement with long-term water and fertilizer retention.

[0007] To achieve the objectives of this invention, the following technical solution is adopted: This invention provides a method for preparing a soil conditioner, comprising the following steps: S1. Add the first peat, humic acid and mixed activator to water, and carry out the first reaction at 55~65℃. Then add an oxidant to carry out the second reaction to obtain activated peat humic acid slurry. The mixed activator includes potassium hydroxide and potassium carbonate. S2. Mix the second peat, attapulgite soil and binder, then add the activated peat humic acid slurry and calcium and magnesium ion mixed aqueous solution, and age to obtain a soil conditioner.

[0008] In existing technologies, if peat and humic acid are directly mixed physically, a large amount of humic substances in the peat are in a bound state, a large molecular aggregate state, or are buried in fibers, with few active functional groups exposed. When directly applied to the soil, the short-term ion exchange and nutrient complexation capacity cannot be fully utilized, resulting in low short-term soil fertility retention and nutrient activation efficiency, and failing to quickly provide sufficient and effective nutrients to crops. If strong alkali treatment is used to enhance the activity of humic acid, it will damage the original fiber and pore structure of the peat, causing the peat to lose its long-term soil aeration and water retention skeletal support function.

[0009] The method for preparing the soil conditioner provided by this invention involves using potassium hydroxide and potassium carbonate as a mixed activator to react the first peat and added humic acid in the first reaction. This process gently breaks down the dense structure of the peat fibers, efficiently dissolving more active humic acid and avoiding excessive damage to organic matter from a single strong alkali. Then, a second oxidation reaction is carried out using an oxidant. The oxidant breaks the condensation bonds of the humic acid macromolecules, oxidizing the inert carbon sites into active groups such as carboxyl groups, exposing internal active sites, and effectively improving the activity and water solubility of humic acid. The combination of these two steps can significantly enhance the product's ability to absorb soil nutrients, giving it better soil-improving activity for the subsequent preparation of high-performance conditioners.

[0010] The method for preparing the soil conditioner provided by this invention involves pre-mixing second peat, attapulgite soil, and a binder to fully expand the pore structure; adding the activated peat humic acid slurry to achieve uniform loading of water-soluble humic acid on the carrier pores and surface; and adding a mixed aqueous solution of calcium and magnesium ions to generate calcium-magnesium bound humic acid through a bridging reaction, achieving a balance between water-soluble humic acid and calcium-magnesium bound humic acid. This method not only stabilizes the conditioner particle structure but also slowly releases the active substance water-soluble humic acid, effectively improving soil properties over a long period and significantly enhancing the fertilizer retention and slow-release capacity.

[0011] The method for preparing soil conditioner provided by this invention focuses on enhancing humic acid activity in step S1 and controlling the release of water-soluble humic acid in step S2. The two steps work together to give the conditioner the dual advantages of rapid soil improvement and long-term fertilizer regulation.

[0012] Preferably, in S1 and S2, the first peat and the second peat further include drying and pulverizing before use.

[0013] More preferably, the drying temperature is 50~60℃.

[0014] Preferably, in S1 and S2, the mass ratio of the first peat to the second peat is (15~20):(32~45).

[0015] Preferably, in S1 and S2, the moisture content of the first peat and the second peat is 5% to 15%, and the particle size is 40 to 100 mesh. Preferably, in S1, the mass ratio of the first peat to humic acid is (15 to 20): (18 to 26).

[0016] Preferably, in S1, the mass ratio of the mixed activator to the first peat is (2~3):(15~20).

[0017] Preferably, in S1, the mass ratio of potassium hydroxide to potassium carbonate is 1:(2~4).

[0018] Preferably, in S1, the pH is adjusted to 9-10 before the first reaction.

[0019] More preferably, the pH adjustment is performed using a 1.3~1.8 mol / L potassium hydroxide solution.

[0020] Preferably, in S1, the time for the first reaction is 40-50 minutes.

[0021] Preferably, in S1, the mass ratio of the oxidant to humic acid is (0.4~0.6):(18~26).

[0022] Preferably, in S1, the oxidant is hydrogen peroxide.

[0023] More preferably, the hydrogen peroxide is an aqueous solution of hydrogen peroxide with a concentration of 0.25~0.35 mol / L.

[0024] For example, the hydrogen peroxide aqueous solution is added dropwise over a period of 25-35 minutes.

[0025] Preferably, in S1, the temperature of the second reaction is 55~65℃ and the time is 80~100min.

[0026] Preferably, in S1, the second reaction is followed by concentration.

[0027] More preferably, the concentration temperature is 45~55℃ and the vacuum degree is -0.07~-0.08MPa.

[0028] More preferably, the concentration endpoint is that the solid content of the concentrated slurry is 50% to 60%.

[0029] Preferably, in S2, the mass ratio of the second peat to attapulgite is (32~45):(10~15).

[0030] Preferably, in S2, the mass ratio of the second peat to the binder is (32~45):(2~3).

[0031] Preferably, in S2, the binder is at least one of pregelatinized starch, corn starch, or tapioca starch.

[0032] More preferably, the binder is pregelatinized starch.

[0033] Preferably, in S2, the mixing rate is 450~500 r / min and the time is 8~12 min.

[0034] Preferably, in S2, the activated peat humic acid slurry is added by spraying.

[0035] More preferably, the spraying includes: spraying the activated peat humic acid slurry into the mixture at a stirring rate of 600~650 r / min.

[0036] More preferably, the spraying time is 20-30 minutes.

[0037] Preferably, in S2, the mass-to-volume ratio of the second peat to the calcium-magnesium ion mixed aqueous solution is (32~45) kg:20 L, and the concentration of calcium salt in the calcium-magnesium ion mixed aqueous solution is 0.2~0.3 kg / L, and the concentration of magnesium salt is 0.02~0.1 kg / L.

[0038] More preferably, the calcium salt is calcium nitrate.

[0039] More preferably, the magnesium salt is magnesium sulfate.

[0040] Preferably, in S2, the calcium and magnesium ion mixed aqueous solution is added 3 to 5 times.

[0041] Preferably, in step S2, after each addition of the calcium and magnesium ion mixed aqueous solution, it is necessary to mix for 3 to 10 minutes.

[0042] The study found that fully water-soluble humic acid has a faster initial dispersion and complexation ability, but its resistance to leaching is relatively insufficient; fully acid-precipitated or fully calcified humic acid has higher stability, but its water dispersibility and initial rhizosphere activity are insufficient.

[0043] The method for preparing the soil conditioner provided by this invention involves first spraying activated peat humic acid slurry into a mixture of second peat and attapulgite, allowing the activated humic acid to enter the peat pores in advance and adsorb onto the surface of fibers and mineral carriers. The attapulgite, utilizing its porous and highly adsorbent properties, loads and fixes the activated humic acid, supporting the pore structure of the conditioner and achieving slow release of water and fertilizer. Then, a calcium-magnesium ion mixed aqueous solution is added in batches, causing incomplete bridging of the calcium-magnesium ions and maintaining the coexistence of water-soluble humic acid and calcium-magnesium bound humic acid. This solves the problem of localized divalent humic acid caused by the one-time addition of calcium-magnesium salts in traditional processes. This addresses issues such as excessively high ion concentration, large-scale flocculation and precipitation of humic acid, encapsulation of active sites, and uneven component distribution. Simultaneously, water-soluble humic acid and calcium-magnesium bound humic acid coexist. Water-soluble humic acid participates in nutrient complexation and ion exchange in the early stages of application, while calcium-magnesium bound humic acid significantly reduces the risk of humic acid leaching and continuously participates in soil particle bridging. It gradually transforms into water-soluble humic acid in the soil environment, continuously participating in later nutrient complexation and ion exchange processes, thus maintaining the soil's fertilizer retention and supply capacity for a long time. Overall, this achieves synergy between rapid early-stage regulation and long-term nutrient management.

[0044] Preferably, in step S2, the pH needs to be adjusted to 6.8–7.6 before aging.

[0045] More preferably, the pH adjustment is performed using a lactic acid solution with a mass concentration of 8% to 12%.

[0046] Preferably, in step S2, the aging temperature is 35–50°C and the time is 30–90 min.

[0047] Preferably, in step S2, the aging process further includes granulation, drying, and sieving.

[0048] More preferably, the drying temperature is 45–60°C.

[0049] More preferably, the moisture content of the dried material is 6% to 12%.

[0050] The method for preparing the soil conditioner provided by the present invention employs weak acid conditioning and low-temperature aging to allow some activated humic acid to be deposited and fixed in peat pores and mineral surfaces; low-temperature drying is used to help maintain the rehydration and dispersibility of particles and the activity of humic acid functional groups.

[0051] For example, the first peat and the second peat are at least one of herbaceous peat or woody peat, and the dry basis organic matter content of the first peat and the second peat before drying and pulverizing is 55% to 80%.

[0052] For example, the total dry basis humic acid content in the humic acid is 20% to 80%, and more preferably, the total dry basis humic acid content in the humic acid is 65% to 80%.

[0053] The present invention also provides a soil conditioner, which is prepared by the above-mentioned method for preparing soil conditioners.

[0054] The beneficial effects provided by this invention are: The soil conditioner and its preparation method provided by this invention process peat into two parts: first peat and second peat. It is combined with a mild potassium-containing mixed activator and oxidation process, without the introduction of waste liquid or sodium salt. It simultaneously enhances the activity of humic acid and maintains the organic pore structure, thereby achieving short-term nutrient enhancement and long-term soil structure improvement, avoiding the dual defects of traditional processes.

[0055] The soil conditioner and its preparation method provided by this invention achieve the coexistence of water-soluble and bound humic acid by stepwise spraying of calcium and magnesium reagents, which incompletely bridges calcium and magnesium, avoids local flocculation and encapsulation of humic acid, and balances the rapid regulation in the early stage with the long-term fertilizer retention and supply in the later stage. Detailed Implementation

[0056] The present invention will be further described in detail below through specific embodiments, but this is only for the purpose of helping to understand the present invention and enabling those skilled in the art to implement or use the present invention, and does not constitute any limitation on the present invention.

[0057] The raw humic acid powder was purchased from Shanxi Jiayou Humic Acid Technology Co., Ltd., with CAS number 1415-93-6 and a powder fineness of 100-120 mesh; the attapulgite clay was purchased from Mingguang Guoxing Attapulgite Co., Ltd.; the woody peat was purchased from Yuanqi Technology (Hangzhou) Co., Ltd.; and the herbaceous peat was purchased from Shouguang Lvtian International Trade Co., Ltd.

[0058] The following description is based on specific embodiments.

[0059] Example 1 This embodiment provides a method for preparing a soil conditioner, including the following steps: S1. Dry the herbaceous peat with a dry basis organic matter content of 60% at 55℃ to a moisture content of 10%, crush it and pass it through a 60-mesh sieve to obtain pretreated herbaceous peat. Divide 55kg of pretreated herbaceous peat into 18kg of first peat and 37kg of second peat. S2. Add 18 kg of first peat and 22 kg of humic acid powder with a total dry humic acid content of 68% to the reactor, add 80 kg of water, stir to form a uniform slurry, add 0.5 kg of potassium hydroxide and 1.5 kg of potassium carbonate, adjust the pH of the system to 9.6 with 1.5 mol / L potassium hydroxide solution, pre-react at 60℃ for 45 min, add 0.5 kg of hydrogen peroxide dropwise within 30 min, the hydrogen peroxide is added in the form of a 0.29 mol / L hydrogen peroxide aqueous solution, continue stirring at 60℃ for 90 min, after the reaction is completed, do not filter or centrifuge, concentrate the slurry at 50℃ and vacuum degree of -0.075 MPa until the solid content of the slurry is 55%, to obtain activated peat humic acid slurry; S3. Add 37 kg of second peat, 12 kg of attapulgite, and 2.5 kg of pregelatinized starch into a high-speed mixer and mix at 470 r / min for 10 min. Spray the resulting mixture with the activated peat humic acid slurry at a stirring rate of 630 r / min for 25 min, so that the slurry is loaded on the surface of the second peat and attapulgite. Prepare a 20 L calcium-magnesium ion mixed aqueous solution by mixing 5 kg of calcium nitrate and 1 kg of magnesium sulfate. Add the calcium-magnesium ion mixed aqueous solution in 4 atomized portions, and continue mixing for 5 min after each addition to complete the calcium-magnesium bridging and obtain the mixed material. S4. Atomize and add a 10% lactic acid solution to slowly adjust the pH of the mixture obtained in S3 to 7.2. Aging at 42℃ for 60 minutes, and then using a disc granulator to form particles with a particle size of 2-4 mm. Dry at 55℃ to a moisture content of 10%, and sieve to obtain the soil conditioner.

[0060] Example 2 This embodiment provides a method for preparing a soil conditioner, including the following steps: S1. Dry the woody peat with a dry basis organic matter content of 55% at 50℃ to a moisture content of 5%, crush it and pass it through a 40-mesh sieve to obtain pretreated woody peat. Divide 60kg of pretreated woody peat into 15kg of first peat and 45kg of second peat. S2. Add 15 kg of first peat and 18 kg of humic acid powder with a total dry humic acid content of 65% to the reactor, add 70 kg of water, stir to form a uniform slurry, add 0.44 kg of potassium hydroxide and 1.76 kg of potassium carbonate, adjust the pH of the system to 9.0 with 1.3 mol / L potassium hydroxide solution, pre-react at 55℃ for 50 min, add 0.4 kg of hydrogen peroxide dropwise over 25 min, the hydrogen peroxide is added in the form of a 0.25 mol / L hydrogen peroxide aqueous solution, continue stirring at 55℃ for 100 min, after the reaction is completed, do not filter or centrifuge, concentrate the slurry at 45℃ and vacuum degree of -0.07 MPa until the solid content of the slurry is 50%, to obtain activated peat humic acid slurry; S3. Add 45 kg of second peat, 15 kg of attapulgite, and 2 kg of corn starch into a high-speed mixer and mix at 450 r / min for 12 min. Spray the resulting mixture with the activated peat humic acid slurry at a stirring rate of 650 r / min for 20 min, so that the slurry is loaded on the surface of the second peat and attapulgite. Prepare 20 L of calcium-magnesium ion mixed aqueous solution with 4.5 kg of calcium nitrate and 0.5 kg of magnesium sulfate. Add the calcium-magnesium ion mixed aqueous solution in 3 atomized portions, and continue mixing for 10 min after each addition to complete the calcium-magnesium bridging and obtain the mixed material. S4. Add 8% lactic acid solution via atomization to slowly adjust the pH of the mixture obtained in S3 to 6.8. Aging at 35℃ for 90 minutes, then using a disc granulator to form particles with a diameter of 2-4 mm. Drying at 45℃ to a moisture content of 12%, and sieving, yielding the soil conditioner.

[0061] Example 3 This embodiment provides a method for preparing a soil conditioner, including the following steps: S1. Dry the herbaceous peat with a dry basis organic matter content of 80% at 60℃ to a moisture content of 15%, crush it and pass it through a 100-mesh sieve to obtain pretreated herbaceous peat. Divide 52kg of pretreated herbaceous peat into 20kg of first peat and 32kg of second peat. S2. Add 20 kg of first peat and 26 kg of humic acid powder with a total dry humic acid content of 80% to the reactor, add 90 kg of water, stir to form a uniform slurry, add 1 kg of potassium hydroxide and 2 kg of potassium carbonate, adjust the pH of the system to 10.0 with 1.8 mol / L potassium hydroxide solution, pre-react at 65℃ for 40 min, add 0.6 kg of hydrogen peroxide dropwise within 35 min, the hydrogen peroxide is added in the form of a 0.35 mol / L hydrogen peroxide aqueous solution, continue stirring at 65℃ for 80 min, after the reaction is completed, do not filter or centrifuge, concentrate the slurry at 55℃ and vacuum degree of -0.08 MPa until the solid content of the slurry is 60%, to obtain activated peat humic acid slurry; S3. Add 32kg of second peat, 10kg of attapulgite and 3kg of cassava starch into a high-speed mixer and mix at 500r / min for 8min. Spray the resulting mixture with the activated peat humic acid slurry at a stirring rate of 600r / min for 30min, so that the slurry is loaded on the surface of the second peat and attapulgite. Prepare 20L of calcium magnesium ion mixed aqueous solution with 6kg of calcium nitrate and 2kg of magnesium sulfate. Add the calcium magnesium ion mixed aqueous solution in 5 atomized portions, and continue mixing for 3min after each addition to complete the calcium magnesium bridging and obtain the mixed material. S4. Atomize and add a 12% (w / w) lactic acid solution to slowly adjust the pH of the mixture obtained in S3 to 7.6. Aging at 50℃ for 30 minutes, then using a disc granulator to form particles with a diameter of 2-5 mm, drying at 60℃ to a moisture content of 6%, and sieving to obtain the soil conditioner.

[0062] Comparative Example 1 This comparative example provides a soil conditioner that uses the same raw materials and dosage as Example 1, but differs from Example 1 in that all raw materials in Example 1 of this invention are physically mixed only. The preparation method of the soil conditioner provided in this comparative example includes the following steps: 55 kg of herbal peat, 22 kg of humic acid powder, 12 kg of attapulgite, 5 kg of calcium nitrate, 1 kg of magnesium sulfate, 2.5 kg of pregelatinized starch, 0.5 kg of potassium hydroxide, and 1.5 kg of potassium carbonate are all put into a common mixing equipment and stirred continuously at a rate of 470 r / min for 25 min to ensure that all raw materials are completely physically mixed. Then, the mixture is directly granulated into particles with a particle size of 2-4 mm using a disc granulator, dried at 55℃ to a moisture content of 10%, and sieved to obtain the finished product. The entire process does not involve peat grading, activation reaction, oxidation treatment, stepwise atomization with calcium and magnesium reagent solution, or aging.

[0063] Comparative Example 2 This comparative example provides a soil conditioner that uses the same raw materials and dosage as Example 1. The difference from Example 1 is that all peat in Example 1 of this invention is activated by alkali-oxygen and is not divided into first peat and second peat. The preparation method of the soil conditioner provided in this comparative example includes the following steps: S1. Dry the herbaceous peat with a dry basis organic matter content of 60% at 55℃ until the moisture content is 10%, crush it and pass it through a 60-mesh sieve to obtain pretreated herbaceous peat. S2. Add 55 kg of pretreated herbal peat and 22 kg of humic acid powder with a total dry humic acid content of 66% to the reactor. Add 80 kg of water and stir to form a uniform slurry. Add 0.5 kg of potassium hydroxide and 1.5 kg of potassium carbonate. Adjust the pH of the system to 9.6 with 1.5 mol / L potassium hydroxide solution. Pre-react at 60℃ for 45 min. Add 0.5 kg of hydrogen peroxide dropwise over 30 min. The hydrogen peroxide is added in the form of a 0.29 mol / L hydrogen peroxide aqueous solution. Continue stirring and reacting at 60℃ for 90 min. After the reaction is completed, do not filter or centrifuge. Concentrate the slurry to a solid content of 55% under 50℃ and a vacuum degree of -0.075 MPa to obtain activated peat humic acid slurry. S3. Add 12 kg of attapulgite clay and 2.5 kg of pregelatinized starch to a high-speed mixer and mix at 470 r / min for 10 min. Then, spray the activated peat humic acid slurry at a stirring rate of 630 r / min and continue spraying and mixing for 25 min. Next, prepare 20 L of calcium magnesium ion mixed aqueous solution with 5 kg of calcium nitrate and 1 kg of magnesium sulfate. Add the calcium magnesium ion mixed aqueous solution in 4 atomized portions. After each addition, continue mixing for 5 min to complete the bridging and obtain the mixed material. S4. Add 10% lactic acid solution by atomization, slowly adjust the pH of the mixture to 7.2, age at 42℃ for 60 minutes, granulate into particles with a diameter of 2-4 mm using a disc granulator, dry at 55℃ to a moisture content of 10%, and then sieve to obtain the soil conditioner.

[0064] Comparative Example 3 This comparative example provides a soil conditioner that differs from Example 1 in that: Step S3 does not involve adding a mixed aqueous solution of calcium and magnesium ions; The preparation method of the soil conditioner provided in this comparative example includes the following steps: S3. Add 37 kg of second peat, 12 kg of attapulgite and 2.5 kg of pregelatinized starch into a high-speed mixer and mix at a rate of 470 r / min for 10 min. The resulting mixture is then sprayed into the activated peat humic acid slurry at a stirring rate of 630 r / min for 25 min, so that the slurry is loaded on the surface of the second peat and attapulgite to obtain a mixture. The other components and dosages, preparation methods and process conditions are the same as in Example 1 of this invention.

[0065] Experimental Example 1 To verify the soil improvement effect of soil conditioners, the following performance test was conducted.

[0066] 1. Soil aggregate structure test Typical northern severely saline-alkali soil was taken, and soil conditioners prepared in each example and comparative example were added at a mass ratio of 2%. After thorough mixing, the mixture was placed in soil cylinders and kept at a constant temperature of 25℃. Deionized water was added periodically at 60% of the field water holding capacity for 90 days of equilibration. According to the agricultural industry standard NY / T 1121.19-2008, the content of water-stable aggregates with a particle size greater than 0.25 mm in the improved soil was determined by wet sieving. On the 30th day of the incubation experiment, 50 g of naturally air-dried test soil sample was taken, placed on a standard sieve, and shaken uniformly in water for 30 min. Soil samples from each sieve were collected, dried, and weighed. The mass percentage of aggregates with a particle size greater than 0.25 mm was calculated. The test results are shown in Table 1. 2. Test on the sustained effect of soil aggregates Samples were taken on the 7th and 90th days of the above-mentioned severe saline-alkali soil incubation experiment to determine the content of water-stable aggregates with a particle size greater than 0.25 mm, in order to compare the initial and sustained effects of different treatments. The test results are shown in Table 1.

[0067] Table 1 After cultivation, the content of water-stable aggregates with a particle size greater than 0.25 mm in the samples of Examples 1-3 steadily increased with the cultivation period, and the content exceeded 60% after 90 days, which was much higher than that of Comparative Examples 1-3. Water-stable aggregates with a particle size greater than 0.25 mm are the core indicator that directly reflects the effect of soil physical structure improvement. The higher the content, the better the soil's resistance to water erosion, water retention and fertilizer retention, and the stability of the aggregate structure, which directly proves that the soil conditioner of this invention has excellent soil improvement performance.

[0068] Comparative Example 1 uses a conventional physical mixing process. The water-soluble humic acid, the active ingredient, is not bound or fixed, resulting in a very low proportion of large aggregates throughout the process, offering almost no long-term improvement effect. On day 90, the content of water-stable aggregates with a particle size greater than 0.25 mm was only 22.1%. Comparative Example 2 involves the activation of all peat, which disrupts the peat's organic framework. Subsequently, the content of large aggregates decreases instead of increasing, failing to support the soil's physical structure in the long term. On day 90, the content of water-stable aggregates with a particle size greater than 0.25 mm was only 30.2%. Comparative Example 3 does not involve the addition of calcium and magnesium ions for bridging and fixation. The activated humic acid is easily lost with water. Initially, on day 7, the content of water-stable aggregates with a particle size greater than 0.25 mm was only 22.7%, and the improvement effect also significantly diminished later, with the content of water-stable aggregates with a particle size greater than 0.25 mm decreasing from 28.4% on day 30 to 25.9% on day 90.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, or improvements 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 a soil conditioner, characterized in that, Includes the following steps: S1. Add the first peat, humic acid and mixed activator to water, and carry out the first reaction at 55~65℃. Then add an oxidant to carry out the second reaction to obtain activated peat humic acid slurry. The mixed activator includes potassium hydroxide and potassium carbonate. S2. Mix the second peat, attapulgite soil and binder, then add the activated peat humic acid slurry and calcium and magnesium ion mixed aqueous solution, and age to obtain a soil conditioner.

2. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S1 and S2, the mass ratio of the first peat to the second peat is (15~20):(32~45); and / or In S1, the mass ratio of the first peat to humic acid is (15~20):(18~26); and / or In S1, the mass ratio of the mixed activator to the first peat is (2~3):(15~20); and / or In S1, the mass ratio of potassium hydroxide to potassium carbonate is 1:(2~4).

3. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S1, the time for the first reaction is 40-50 minutes.

4. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S1, the mass ratio of the oxidant to humic acid is (0.4~0.6):(18~26); and / or In S1, the oxidant is hydrogen peroxide; and / or In S1, the temperature of the second reaction is 55~65℃ and the time is 80~100min.

5. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S2, the mass ratio of the second peat to attapulgite is (32~45):(10~15); and / or In S2, the mass ratio of the second peat to the binder is (32~45):(2~3); and / or In S2, the binder is at least one of pregelatinized starch, corn starch, or tapioca starch.

6. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S2, the mixing rate is 450~500 r / min and the time is 8~12 min.

7. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S2, the mass-to-volume ratio of the second peat to the calcium-magnesium ion mixed aqueous solution is (32~45) kg:20 L, and the concentration of calcium salt in the calcium-magnesium ion mixed aqueous solution is 0.2~0.3 kg / L, and the concentration of magnesium salt is 0.02~0.1 kg / L.

8. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S2, the calcium and magnesium ion mixed aqueous solution is added 3 to 5 times.

9. The method for preparing the soil conditioner as described in claim 1, characterized in that, In S2, the pH needs to be adjusted to 6.8–7.6 before aging; and / or In S2, the aging temperature is 35–50°C and the time is 30–90 min.

10. A soil conditioner, prepared by the method of any one of claims 1-9.

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