Soil conditioner for soil acidification treatment as well as preparation method and application of soil conditioner

Abstract

The invention relates to the technical field of soil conditioners, in particular to a soil conditioner for soil acidification treatment as well as a preparation method and application of the soil conditioner. Comprising the following components in parts by weight: 20-35 parts of red mud, 10-15 parts of a humic acid-sodium alginate compound, 10-15 parts of zeolite, 5-8 parts of a silicon-calcium-magnesium fertilizer, 4-8 parts of an acid-proof bacterial agent and 10-15 parts of a bio-based adhesive. The acidified soil treatment effect can be better, and the effect is more durable.

Description

Technical Field

[0001] This application relates to the technical field of soil conditioners, and in particular to a soil conditioner for soil acidification control, its preparation method and application. Background Art

[0002] Soil acidification refers to the process in which the concentration of hydrogen ions (H⁺) in the soil increases or the base ions (such as Ca²⁺, Mg²⁺, K⁺, etc.) are lost, resulting in a decrease in the soil pH value and an increase in acidity. Soil acidification causes multi-dimensional harms to the agricultural ecosystem, crop growth and environmental health, specifically manifested as follows: I. Soil structure damage Soil compaction and decreased air permeability Acidification causes the collapse of soil aggregate structure, forming a dense block, with the porosity reduced by 30%-50%, increasing the resistance to root extension and easily forming "stunted seedlings"; the ability to retain water and fertilizers is lost. The acidic environment accelerates the leaching of base ions such as calcium, magnesium, and potassium, reducing the soil water holding capacity by 20%-40% and intensifying the loss of nutrients with water.

[0003] II. Nutrient imbalance and decreased effectiveness, inactivation of macronutrients The effectiveness of nitrogen, phosphorus, and potassium decreases as the pH value decreases. When pH < 5.0, the phosphorus fixation rate increases by 40%-60%, and crop nutrient deficiency symptoms occur frequently. Activation of toxic elements, the concentration of free ions such as aluminum, manganese, and iron increases, resulting in crop root poisoning (such as aluminum poisoning of wheat roots, reducing production by 30%-50%). Inhibition of beneficial bacteria, the number of beneficial microorganisms such as ammonifying bacteria and nitrogen-fixing bacteria decreases by 60%-80%, nitrification is blocked, and the nitrogen fertilizer utilization rate decreases by 40%.

[0004] Therefore, it is necessary to control acidified soil to reduce the above harms. Currently, in the control of acidified soil, soil conditioners are mainly used. Soil conditioners for soil acidification control restore soil health by neutralizing acidity, supplementing base ions, improving soil structure, etc. Most traditional acidic soil conditioners directly use quicklime, slaked lime, and limestone powder, and the effect of increasing pH is significant, but long-term application leads to potential "secondary ashification" or re-acidification risks in the soil; in addition, oyster shells are also widely applied due to their easy availability, low price, environmental friendliness, etc., but they have potential heavy metal risks. Therefore, there is still much room for improvement in soil conditioners. Summary of the Invention

[0005] In the first aspect, this application provides a soil conditioner for soil acidification control.

[0006] This application adopts the following technical solutions: A soil conditioner for soil acidification control, by weight, comprises the following components: 20-35 parts of red mud, 10-15 parts of humic acid-sodium alginate complex, 10-15 parts of zeolite, 5-8 parts of silicon-calcium-magnesium fertilizer, 4-8 parts of acid-tolerant bacterial agent, and 10-15 parts of bio-based binder.

[0007] By adopting the above technical solution, firstly, red mud is rich in Fe2O3 and CaO, which can fix heavy metals (such as Cd²⁺, Pb²⁺) through ion exchange and precipitation, and can cooperate with zeolite to adjust the pH, thereby conditioning acidic soil; humic acid has a large number of carboxyl groups. In acidic soil, the protonated carboxyl group molecules are negatively charged, and they can adsorb H⁺ electrostatically to neutralize soil acidity. In addition, humic acid complexes heavy metals, and sodium alginate binds to heavy metals through carboxyl groups to form stable chelates. In addition, after the two are crosslinked, a gel network is formed to enhance water and fertilizer retention, thereby promoting plant growth; the acid-tolerant bacterial agent can maintain its activity in an acidic environment, secrete a variety of secondary metabolites, promote the development of crop roots, and cooperate with the silicon-calcium-magnesium fertilizer to condition the soil and improve the soil's acid resistance.

[0008] Optionally, the humic acid-sodium alginate complex is prepared by the following method: dissolve humic acid and sodium alginate separately, then mix the two solutions, add polyethylene glycol, continuously stir and react, and then dry and crush to obtain the humic acid-sodium alginate complex.

[0009] By adopting the above technical solution, the humic acid-sodium alginate complex crosslinks to form a network structure, which can effectively control the loss rate of humic acid, thereby improving the persistence of the conditioner in conditioning acidified soil. In addition, under the action of polyethylene glycol, the crosslinking effect can be further improved, and the stability of the overall system can be further improved.

[0010] Optionally, by weight, it further comprises 1-3 parts of polyglutamic acid.

[0011] By adopting the above technical solution, polyglutamic acid, as a water-retaining agent and heavy metal chelating agent, forms a three-dimensional network with the humic acid-sodium alginate complex to improve the stability of the overall structure. In addition, the adsorption capacity of polyglutamic acid for Ca²⁺ and Mg²⁺ is 100 times that of natural soil, which can displace H⁺ and Al³⁺ on soil colloids, increase the base saturation degree, and reduce the exchangeable acidity of the soil.

[0012] Optionally, the bio-based binder is selected from corn starch.

[0013] By adopting the above technical solution, the molecular chains of corn starch form a coating with the particles through hydrogen bonds and van der Waals forces, thereby improving the persistence of acid conditioning. The hydroxyl groups on the starch molecular chains form five-membered ring chelates with Ca²⁺ and Mg²⁺, enhancing the residence time of base ions in the soil and reducing the competitive adsorption of Al³⁺ and H⁺. In addition, the degradation products of corn starch can provide energy for acid-tolerant agents, promoting the proliferation and action of acid-tolerant agents.

[0014] Optionally, the zeolite is surface-modified with an epoxy group silane coupling agent.

[0015] Optionally, the zeolite is modified through the following steps: dissolving 3-glycidoxypropyltriethoxysilane in an ethanol solution, adding zeolite particles to the ethanol solution of 3-glycidoxypropyltriethoxysilane, stirring and reacting, then filtering and drying to obtain the surface-modified zeolite.

[0016] By adopting the above technical solution, the zeolite is surface-modified with an epoxy group silane coupling agent, making the zeolite surface carry epoxy groups. The epoxy groups are prone to ring-opening polymerization with the hydroxyl groups in the corn starch chain segments, so that the corn starch can better coat the zeolite surface, thereby improving the mechanical strength of the overall structure and having better durability.

[0017] Optionally, the acid-tolerant agent is selected from one or more of phosphate-solubilizing bacteria, Bacillus subtilis, Brevibacillus laterosporus, and Bacillus laterosporus.

[0018] By adopting the above technical solution, the above acid-tolerant agent has the characteristics of fast colonization and reproduction speed, can inhibit the reproduction of other pathogenic microorganisms, has strong acid and alkali resistance, and can maintain its activity in an acidic environment.

[0019] In a second aspect, the present application provides a preparation method of a soil conditioner for soil acidification control in the above scheme.

[0020] A preparation method of a soil conditioner includes the following steps; (1) Mix red mud, humic acid-sodium alginate complex, zeolite, silicon-calcium-magnesium fertilizer, acid-tolerant agent, and bio-based binder according to the formula to obtain a mixed raw material; (2) Place the mixed raw material in a granulator for granulation, and spray deionized water through a sprayer during the granulation process to obtain conditioner particles; (3) Dry the conditioner particles obtained in step (2) to obtain the product.

[0021] By adopting the above technical solution, the particles of the soil conditioner can be prepared, which is convenient for application.

[0022] In a third aspect, the present application provides an application of a soil conditioner in the above scheme.

[0023] Application of a soil conditioner, where the soil conditioner is applied to the treatment of acidified soil.

[0024] In summary, this application includes at least one of the following beneficial effects: 1. In the solution of this application, through the synergy and enhancement of multiple components, the integrated treatment of acidified soil, soil structure repair, and microbial ecological reconstruction is achieved. Moreover, the effect of acid treatment is good and persistent, which is suitable for the sustainable repair of acidic soil. Detailed implementation mode

[0025] The following further elaborates on this application.

[0026] Preparation example 1: Preparation of humic acid-sodium alginate composite Add 5 parts of humic acid (the average molecular weight of humic acid is 5000 Da) to 100 parts of deionized water, and stir until dissolved at 60 °C to obtain a humic acid solution; add 5 parts of sodium alginate to 100 parts of deionized water, and stir until dissolved at 60 °C to obtain a sodium alginate solution; then mix the humic acid solution and the sodium alginate solution, stir evenly, and add 1 part of polyethylene glycol to promote the cross-linking of humic acid and sodium alginate. After continuous stirring for 1 h; then filter, and place the filtered product in an oven, dry it to constant weight at 50 °C, and crush and grind the product with a grinder and sieve it to obtain a humic acid-sodium alginate composite with an average particle size of 1 mm.

[0027] Preparation example 2: Surface modification of zeolite Add 1 part of 3-glycidoxypropyltriethoxysilane to 100 parts of ethanol solution, stir. After 3-glycidoxypropyltriethoxysilane is dissolved, add zeolite to the obtained coupling agent solution, react for 4 h, then take out the zeolite, rinse it with deionized water, and then dry it for standby.

[0028] Example 1 A soil conditioner for soil acidification treatment is prepared through the following steps: 1. By weight, mix 20 parts of red mud, 15 parts of humic acid-sodium alginate composite, 15 parts of the surface-modified zeolite in Preparation example 2, 5 parts of calcium silicate potassium fertilizer, 4 parts of acid-resistant bacteria agent, and 10 parts of bio-based binder to obtain a mixed raw material; among them, the acid-resistant bacteria agent is selected from phosphate-solubilizing bacteria and Bacillus subtilis, and the mass ratio of the two is 1:1, and the bio-based binder is selected from corn starch; (2) Place the mixed raw materials obtained in the above steps in a disk granulator for granulation. During the granulation process, deionized water is sprayed in through a sprayer to obtain conditioner granules, where the mass ratio of deionized water to the mixed raw materials is 1:5; (3) Place the conditioner granules obtained in step (2) in a forced-air drying oven and dry them at 60 °C for 2 h. After drying is completed, the soil conditioner is obtained.

[0029] Example 2 A soil conditioner for soil acidification treatment is prepared through the following steps: 2. By weight, mix 35 parts of red mud, 10 parts of humic acid-sodium alginate complex, 10 parts of the surface-modified zeolite in Preparation Example 2, 8 parts of silicon-calcium-potassium fertilizer, 8 parts of acid-resistant bacteria agent, and 15 parts of bio-based binder to obtain mixed raw materials; among them, the acid-resistant bacteria agent is selected from phosphate-solubilizing bacteria and Bacillus subtilis, and the mass ratio of the two is 1:1, and the bio-based binder is selected from corn starch; (2) Place the mixed raw materials obtained in the above steps in a disk granulator for granulation. During the granulation process, deionized water is sprayed in through a sprayer to obtain conditioner granules, where the mass ratio of deionized water to the mixed raw materials is 1:5; (3) Place the conditioner granules obtained in step (2) in a forced-air drying oven and dry them at 60 °C for 2 h. After drying is completed, the soil conditioner is obtained.

[0030] Example 3 A soil conditioner for soil acidification treatment is prepared through the following steps: 3. By weight, mix 25 parts of red mud, 12 parts of humic acid-sodium alginate complex, 10 parts of the surface-modified zeolite in Preparation Example 2, 8 parts of silicon-calcium-potassium fertilizer, 4 parts of acid-resistant bacteria agent, 12 parts of bio-based binder, and 1 part of polyglutamic acid to obtain mixed raw materials; among them, the acid-resistant bacteria agent is selected from phosphate-solubilizing bacteria and Bacillus subtilis, and the mass ratio of the two is 1:1, and the bio-based binder is selected from corn starch; (2) Place the mixed raw materials obtained in the above steps in a disk granulator for granulation. During the granulation process, deionized water is sprayed in through a sprayer to obtain conditioner granules, where the mass ratio of deionized water to the mixed raw materials is 1:5; (3) Place the conditioner granules obtained in step (2) in a forced-air drying oven and dry them at 60 °C for 2 h. After drying is completed, the soil conditioner is obtained.

[0031] Example 4 A soil conditioner for soil acidification treatment is prepared through the following steps: 4. By weight, 30 parts of red mud, 15 parts of humic acid-sodium alginate complex, 15 parts of the surface-modified zeolite in Preparation Example 2, 5 parts of calcium silicate potassium fertilizer, 6 parts of acid-resistant bacteria agent, 15 parts of bio-based binder, and 3 parts of polyglutamic acid were mixed to obtain a mixed raw material; wherein, the acid-resistant bacteria agent was selected from phosphate-solubilizing bacteria and Bacillus subtilis, and the mass ratio of the two was 1:1, and the bio-based binder was selected from corn starch; (2) The mixed raw material obtained in the above step was placed in a disk granulator for granulation, and deionized water was sprayed in through a sprayer during the granulation process to obtain conditioner particles, wherein the mass ratio of deionized water to the mixed raw material was 1:5; (3) The conditioner particles obtained in step (2) were placed in a forced-air drying oven and dried at 60 °C for 2 h, and after drying was completed, the soil conditioner was obtained.

[0032] Example 5 Compared with Example 1, the process steps and components of this example are the same, except that unmodified zeolite was used to replace the surface-modified zeolite in Example 1 in equal amounts.

[0033] Comparative Example 1 Compared with Example 1, the process steps and components of this comparative example are the same, except that zeolite was not added.

[0034] Comparative Example 2 Compared with Example 1, the process steps and components of this comparative example are the same, except that humic acid was used to replace the humic acid-sodium alginate complex in equal amounts.

[0035] In an outdoor area with a flat terrain and a soil pH of 5.01, it was divided into multiple areas with the same area and isolated from each other so that components such as moisture could not interfere with each other. Fertilization was carried out on each area at a fertilization rate of 120 kg / mu, and the conditioner was mixed evenly with the soil, and the pH value of the soil was measured every 3 months. The pH values of the soil after fertilization with the conditioners of Examples 1-5 and Comparative Examples 1-2 are as follows in the table.

[0036] Table 1 pH values of the soil after fertilization with the conditioners of Examples 1-5 and Comparative Examples 1-2 March (pH) June (pH) September (pH) December (pH) Example 1 6.31 6.29 6.27 6.23 Example 2 6.36 6.33 6.27 6.22 Example 3 6.45 6.41 6.40 6.38 Example 4 6.51 6.50 6.48 6.44 Example 5 6.30 6.27 6.20 6.01 Comparative Example 1 5.91 5.81 5.60 5.31 Comparative Example 2 6.45 6.01 5.92 5.31 Through the comparison between Example 1 and Example 5, it can be seen that after the zeolite is surface-modified, a certain interaction force can be formed between the zeolite and the surface of corn starch, which can make the system more stable, and thus make the acid resistance more persistent. In addition, from the comparison between Comparative Example 1 and Example 2, it can also be seen that the humic acid-sodium alginate complex can form a cross-linked network structure in the system, and can also make the acid-resistant components release slowly, so as to achieve the persistence of soil acidification control. Therefore, the soil conditioner in this application can be applied to the treatment of acidified soil.

[0037] The above are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A soil conditioner for soil acidification control, characterized in that: By weight parts, it includes the following components: 20 - 35 parts of red mud, 10 - 15 parts of humic acid - sodium alginate complex, 10 - 15 parts of zeolite, 5 - 8 parts of calcium - silicon - magnesium fertilizer, 4 - 8 parts of acid - resistant bacterium agent, 10 - 15 parts of bio - based binder; the humic acid - sodium alginate complex is prepared by the following method: dissolve humic acid and sodium alginate respectively, then mix the two solutions, add polyethylene glycol, continuously stir and react, and then dry and crush to obtain the humic acid - sodium alginate complex; the zeolite is surface - modified by epoxy - based silane coupling agent.

2. The soil conditioner for soil acidification control according to claim 1, characterized in that: By weight parts, it also includes 1 - 3 parts of polyglutamic acid.

3. The soil conditioner for soil acidification control according to claim 1, characterized in that: The bio - based binder is selected from corn starch.

4. The soil conditioner for soil acidification control according to claim 3, characterized in that: The zeolite is modified by the following steps: dissolve 3 - glycidoxypropyltriethoxysilane in an ethanol solution, add zeolite particles into the ethanol solution of 3 - glycidoxypropyltriethoxysilane, stir and react, then filter and dry to obtain the surface - modified zeolite.

5. The soil conditioner for soil acidification control according to claim 4, characterized in that: The acid - resistant bacterium agent is selected from one or more of phosphate - solubilizing bacteria, Bacillus subtilis, Brevibacillus laterosporus, and Bacillus laterosporus.

6. A preparation method of the soil conditioner for soil acidification control according to any one of claims 1-5, characterized in that: It includes the following steps; (1) Mix red mud, humic acid - sodium alginate complex, zeolite, calcium - silicon - magnesium fertilizer, acid - resistant bacterium agent, and bio - based binder according to the formula to obtain a mixed raw material; (2) Place the mixed raw material in a granulator for granulation, and spray deionized water through a sprayer during the granulation process to obtain conditioner particles; (3) Dry the conditioner particles obtained in step (2) to obtain the product.

7. An application of the soil conditioner for soil acidification control according to any one of claims 1-5, characterized in that: The soil conditioner is applied to the treatment of acidified soil.