Acid-reducing selenium-increasing soil conditioner and preparation method thereof

Abstract

The invention provides an acid-reducing selenium-increasing soil conditioner and a preparation method thereof, and relates to the field of soil conditioners. The soil conditioner capable of reducing acid and increasing selenium is prepared from the following main raw materials: biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw, earthworm liquid fertilizer, silicate bacteria, polyglutamic acid and micromolecular micro-carbon. Through the synergistic effect of the alkaline substance and the modified zeolite, the soil acidity is effectively reduced, meanwhile, activation and release of selenium are promoted, the bio-availability of selenium is improved, the water and fertilizer retention capacity of soil is enhanced through the porous structure of the biochar, a habitat is provided for microorganisms, and soil ecological restoration is promoted. Silicate minerals are decomposed by silicate bacteria, soluble nutrient elements are released, the soil fertility is further improved, and the activity and durability of the modifier are enhanced by adding polyglutamic acid and micromolecular micro-carbon.

Description

Technical Field

[0001] The present invention relates to the technical field of soil conditioners, and specifically to an acid-reducing and selenium-increasing soil conditioner and a preparation method thereof. Background Art

[0002] Traditional acid-reducing technologies mainly neutralize acidic substances in the soil by applying alkaline substances (such as lime, calcium magnesium phosphate fertilizer, etc.) to increase the soil pH value. These alkaline substances combine with hydrogen ions in the soil through chemical reactions, thereby reducing soil acidity. Traditional selenium-increasing technologies mainly increase the selenium content in the soil by applying selenium-containing fertilizers or selenium fertilizers. These selenium-containing substances fix selenium in the soil through chemical reactions or physical adsorption for plants to absorb and utilize. Therefore, how to in-situ improve the biological availability of soil selenium has important practical significance.

[0003] However, most of the existing soil conditioners have single functions, either focusing on acid reduction or on selenium increase, lacking a comprehensive solution to simultaneously solve the problems of soil acidification and selenium deficiency. In addition, most of the existing conditioners use single raw materials and do not fully utilize waste resources, resulting in high production costs and not conforming to the concept of sustainable development. At the same time, the existing conditioners are difficult to maintain good improvement effects during long-term use. For example, alkaline substances such as lime are easily leached in the soil, resulting in a gradual weakening of the acid reduction effect; selenium in selenium-containing fertilizers is easily fixed by the soil and difficult to maintain effectiveness for a long time. In addition, the existing conditioners may cause environmental pollution during the production process. For example, the production of lime requires high-temperature calcination, with high energy consumption and a large amount of carbon dioxide generated; the production of selenium-containing fertilizers may release harmful gases, polluting the environment.

[0004] Therefore, developing a soil conditioner that can simultaneously achieve acid reduction and selenium increase effects has important practical significance. Summary of the Invention

[0005] (I) Technical Problems to be Solved

[0006] Aiming at the deficiencies of the existing technology, the present invention provides an acid-reducing and selenium-increasing soil conditioner and a preparation method thereof, aiming to simultaneously solve the problems of soil acidification and selenium deficiency and overcome the above-mentioned defects of the existing technology.

[0007] (II) Technical Solutions

[0008] To achieve the above object, the present invention is realized through the following technical solutions: A soil acidification-reducing and selenium-enriching agent and its preparation method are made from the following raw materials by weight: 300 parts of biochar, 100 - 200 parts of modified zeolite, 300 - 600 parts of calcium magnesium phosphate fertilizer, 150 - 250 parts of decomposed straw, 80 - 120 parts of earthworm liquid fertilizer, 80 - 100 parts of silicate bacteria, 80 - 100 parts of polyglutamic acid, and 30 - 50 parts of small molecule micro-carbon.

[0009] A preparation method of a soil acidification-reducing and selenium-enriching agent, which is applied to the above-mentioned soil acidification-reducing and selenium-enriching agent, includes the following steps;

[0010] S1. Using food residues as raw materials, pyrolyzing them to obtain biochar, and then activating the biochar after mixing it with potassium hydroxide;

[0011] S2. Using natural zeolite as the base material, mixing natural zeolite with a single-atom catalyst, and then modifying it;

[0012] S3. Mixing the prepared activated biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw, and earthworm liquid fertilizer in proportion and stirring evenly;

[0013] S4. Inoculating silicate bacteria into the mixed solution, stirring evenly and then standing for fermentation for 24 hours;

[0014] S5. Adding polyglutamic acid and small molecule micro-carbon to the fermentation broth, stirring evenly, and then drying it at room temperature to make it into granules.

[0015] Preferably, in the step S1, the food residues are set as one or more of soybean dregs, fruit dregs, or bread crumbs, the pyrolysis temperature of the food residues is set at 300 - 500 °C, and the pyrolysis time is set at 2 - 3 h.

[0016] Preferably, in the step S1, the mixing ratio of biochar to potassium hydroxide is 1:(0.8 - 1.2), the activation temperature of biochar and potassium hydroxide is set at 200 - 300 °C, and the activation time is set at 1 - 2 h.

[0017] Preferably, in the step S2, the single-atom catalyst is set as nano iron powder, nano zinc powder, or copper powder, the mixing ratio of natural zeolite to the single-atom catalyst is 1:0.1, the modification temperature of natural zeolite and the single-atom catalyst is set at 300 - 400 °C, and the modification time is set at 1 - 2 h.

[0018] Preferably, in the step S3, the mixing ratio of activated biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw, and earthworm liquid fertilizer is 300:(100 - 200):(300 - 600):(150 - 250):(80 - 120).

[0019] Preferably, in step S4, the inoculation amount of silicate bacteria is 10^8 CFU / g, and the addition amount of silicate bacteria is 80 - 100 parts.

[0020] Preferably, in step S5, the addition amount of polyglutamic acid is 80 - 100 parts, the addition amount of small molecule micro-carbon is 30 - 50 parts, and the diameter of the dried modifier particles is 2 - 5 mm.

[0021] (III) Beneficial effects

[0022] The present invention provides an acid-reducing and selenium-enriching soil modifier and its preparation method, having the following

[0023] beneficial effects:

[0024] 1. Through the combination of alkaline substances and modified zeolite, the acid reduction and selenium enrichment of the soil are realized simultaneously. The porous structures of biochar and modified zeolite can adsorb acidic ions in the soil, increase the soil pH value, and at the same time promote the activation and release of selenium, making the selenium in the soil exist in a soluble or exchangeable state, and improving the biological availability of selenium.

[0025] 2. Using waste such as food residues to prepare the modifier not only reduces the production cost but also reduces environmental pollution, which conforms to the concept of sustainable development. The biochar after pyrolysis treatment has a rich pore structure, which can improve the water and fertilizer retention capacity of the soil, and at the same time provide a habitat for microorganisms, promoting the restoration of the soil ecosystem.

[0026] 3. Combining with microbial technology, silicate bacteria can decompose silicate minerals, releasing soluble potassium, phosphorus and other nutrient elements, and improving soil fertility. The addition of polyglutamic acid and small molecule micro-carbon further enhances the activity and persistence of the modifier, making it maintain a good modification effect during long-term use. Description of the drawings

[0027] Figure 1 It is the preparation flow chart of the present invention. Specific embodiments

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1:

[0030] An embodiment of the present invention provides an acid-reducing and selenium-enriching soil conditioner and its preparation method, including the preparation of biochar: using soybean dregs as raw materials, pyrolyzing at 300°C for 2 hours to obtain biochar, and then mixing the biochar with potassium hydroxide in a ratio of 1:1 and activating at 200°C for 1 hour. The porous structure of the biochar can adsorb acidic ions in the soil, increase the soil pH value, and at the same time provide a habitat for microorganisms, promoting the restoration of the soil ecosystem.

[0031] Preparation of modified zeolite: Using natural zeolite as the base material, mixing it with nano iron powder in a ratio of 1:0.1 and modifying at 300°C for 1 hour. The modified zeolite has stronger adsorption capacity and catalytic performance, can effectively adsorb acidic ions in the soil, and at the same time promote the activation and release of selenium.

[0032] Mixing of raw materials: Mix 300 g of the prepared activated biochar, 150 g of modified zeolite, 500 g of calcium magnesium phosphate fertilizer, 200 g of decomposed straw, and 100 mL of earthworm liquid fertilizer in proportion and stir evenly. Calcium magnesium phosphate fertilizer can neutralize soil acidity, increase the soil pH value, and at the same time provide necessary nutrient elements for plants.

[0033] Microbial inoculation: Inoculate silicate bacteria (10^8 CFU / g) into the mixed solution at 10% of the total weight of the mixture, stir evenly and then let it stand for fermentation for 24 hours. Silicate bacteria can decompose silicate minerals, release soluble potassium, phosphorus and other nutrient elements, and improve soil fertility.

[0034] Addition of auxiliary materials: Add 100 g of polyglutamic acid and 50 g of small molecule microcarbon to the fermentation broth, stir evenly, and dry at room temperature to make granular conditioner with a diameter of 2 - 5 mm. Polyglutamic acid and small molecule microcarbon can further enhance the activity and persistence of the conditioner, making it maintain good improvement effect during long-term use.

[0035] Experimental data and effects:

[0036] Change in soil pH value: After applying the conditioner, the soil pH value increased from 5.2 to 6.5, and the acidity decreased significantly.

[0037] Change in selenium content: The available selenium content in the soil increased from 0.15 mg / kg to 0.45 mg / kg, and the biological availability of selenium increased significantly.

[0038] Crop growth effect: In the test field where the conditioner was applied, the crop yield increased by 15%, the selenium content increased by 30%, and the crop quality was significantly improved.

[0039] Example two:

[0040] The difference between this example and Example one is:

[0041] Food residue selection: Fruit residue is used as the food residue, which is pyrolyzed at 500 °C for 3 hours. The fruit residue is rich in organic matter and minerals, and the biochar obtained after pyrolysis has higher adsorption capacity and stability.

[0042] Single-atom catalyst selection: Copper powder is used as the single-atom catalyst. The mixing ratio of natural zeolite to copper powder is 1:0.1, and it is modified at 400 °C for 2 hours. Copper powder can enhance the catalytic performance of zeolite and further promote the activation and release of selenium.

[0043] Adjustment of raw material ratio: The mixing ratio of activated biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw and earthworm liquid fertilizer is 300:200:600:250:15. The adjusted ratio can better meet the requirements of different soil conditions and improve the improvement effect.

[0044] Experimental data and effects:

[0045] Change in soil pH value: After applying the soil conditioner, the soil pH value increased from 4.8 to 6.0, and the acidity decreased significantly.

[0046] Change in selenium content: The available selenium content in the soil increased from 0.10 mg / kg to 0.40 mg / kg, and the bioavailability of selenium increased significantly.

[0047] Crop growth effect: In the experimental field where the soil conditioner was applied, the crop yield increased by 18%, the selenium content increased by 35%, and the crop quality was significantly improved.

[0048] Example 3

[0049] Biochar preparation: Using bread residue as the raw material, it is pyrolyzed at 350 °C for 2.5 hours. After obtaining the biochar, the biochar is mixed with potassium hydroxide in a ratio of 1:1 and activated at 250 °C for 1.5 hours. The porous structure of the biochar can adsorb acidic ions in the soil, increase the soil pH value, and at the same time provide a habitat for microorganisms, promoting the restoration of the soil ecosystem.

[0050] Modified zeolite preparation: Using natural zeolite as the substrate, it is mixed with nano iron powder in a ratio of 1:0.1 and modified at 350 °C for 1.5 hours. The modified zeolite has stronger adsorption capacity and catalytic performance, can effectively adsorb acidic ions in the soil, and at the same time promote the activation and release of selenium.

[0051] Raw material mixing: Mix 350 g of the prepared activated biochar, 180 g of modified zeolite, 550 g of calcium magnesium phosphate fertilizer, 220 g of decomposed straw and 110 mL of earthworm liquid fertilizer in proportion and stir evenly. Calcium magnesium phosphate fertilizer can neutralize soil acidity, increase the soil pH value, and at the same time provide necessary nutrient elements for plants.

[0052] Microbial inoculation: Inoculate silicate bacteria (10^8 CFU / g) into the mixed solution at 10% of the total weight of the mixture, stir evenly and then let it stand for fermentation for 24 hours. Silicate bacteria can decompose silicate minerals, release soluble potassium, phosphorus and other nutrient elements, and improve soil fertility.

[0053] Addition of auxiliary materials: Add 100 g of polyglutamic acid and 50 g of small molecule micro-carbon to the fermentation broth, stir evenly, and then dry it at room temperature to make a granular conditioner with a diameter of 2 - 5 mm. Polyglutamic acid and small molecule micro-carbon can further enhance the activity and persistence of the conditioner, so that it can maintain good improvement effect during long-term use.

[0054] Experimental data and effects:

[0055] Change of soil pH value: After applying the conditioner, the soil pH value increased from 5.0 to 6.3, and the acidity decreased significantly.

[0056] Change of selenium content: The available selenium content in the soil increased from 0.12 mg / kg to 0.42 mg / kg, and the biological availability of selenium increased significantly.

[0057] Crop growth effect: In the experimental field where the conditioner was applied, the crop yield increased by 16%, the selenium content increased by 32%, and the crop quality was significantly improved.

[0058] Example 4

[0059] Selection of food residues: The food residues used are bread crumbs, which are pyrolyzed at 400 °C for 3 hours. Bread crumbs are rich in organic matter and minerals, and the biochar prepared after pyrolysis has higher adsorption capacity and stability.

[0060] Selection of single-atom catalyst: The single-atom catalyst used is copper powder, and the mixing ratio of natural zeolite to copper powder is 1:0.1, and it is modified at 350 °C for 1.5 hours. Copper powder can enhance the catalytic performance of zeolite and further promote the activation and release of selenium.

[0061] Adjustment of raw material ratio: The mixing ratio of activated biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw and earthworm liquid fertilizer is 350:200:650:250:15. The adjusted ratio can better meet the requirements of different soil conditions and improve the improvement effect.

[0062] Experimental data and effects:

[0063] Change of soil pH value: After applying the conditioner, the soil pH value increased from 4.5 to 5.8, and the acidity decreased significantly.

[0064] Change of selenium content: The available selenium content in the soil increased from 0.08 mg / kg to 0.38 mg / kg, and the biological availability of selenium increased significantly.

[0065] Crop growth effect: In the experimental field where the modifier was applied, the crop yield increased by 20%, the selenium content increased by 38%, and the crop quality was significantly improved.

[0066] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A soil conditioner for reducing acidity and increasing selenium content, characterized in that, It is made from the following raw materials by weight parts: 300 parts of biochar, 100 - 200 parts of modified zeolite, 300 - 600 parts of calcium magnesium phosphate fertilizer, 150 - 250 parts of decomposed straw, 80 - 120 parts of earthworm liquid fertilizer, 80 - 100 parts of silicate bacteria, 80 - 100 parts of polyglutamic acid, and 30 - 50 parts of small molecule microcarbon.

2. A preparation method of an acid-reducing and selenium-enriching soil conditioner, characterized in that, Applied to a soil acidification - reducing and selenium - enriching soil conditioner described in claim 1, it includes the following steps; S1. Using food residues as raw materials, pyrolyzing them to obtain biochar, and then activating the biochar by mixing it with potassium hydroxide. S2. Using natural zeolite as the substrate, mixing natural zeolite with a single - atom catalyst, and then carrying out modification. S3. Mixing the prepared activated biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw, and earthworm liquid fertilizer in proportion and stirring evenly. S4. Inoculating silicate bacteria into the mixed solution, stirring evenly and then standing for fermentation for 24 hours. S5. Adding polyglutamic acid and small molecule microcarbon to the fermentation broth, stirring evenly, and then drying it at room temperature to make it into granular form.

3. The preparation method of a soil acid reducer and selenium enricher according to claim 2, characterized in that: In the step S1, the food residues are set as one or more of soybean dregs, fruit dregs, or bread dregs. The pyrolysis temperature of the food residues is set at 300 - 500 °C, and the pyrolysis time is set at 2 - 3 h.

4. The preparation method of a soil acid-reducing and selenium-increasing modifier according to claim 2, characterized in that: In the step S1, the mixing ratio of biochar to potassium hydroxide is 1:(0.8 - 1.2). The activation temperature of biochar and potassium hydroxide is set at 200 - 300 °C, and the activation time is set at 1 - 2 h.

5. The preparation method of a soil acid-reducing and selenium-enriching agent according to claim 2, wherein: In the step S2, the single - atom catalyst is set as nano - iron powder, nano - zinc powder, or copper powder. The mixing ratio of natural zeolite to the single - atom catalyst is 1:0.

1. The modification temperature of natural zeolite and the single - atom catalyst is set at 300 - 400 °C, and the modification time is set at 1 - 2 h.

6. The preparation method of a soil acid reducer and selenium enricher according to claim 2, characterized in that: In the step S3, the mixing ratio of activated biochar, modified zeolite, calcium magnesium phosphate fertilizer, decomposed straw, and earthworm liquid fertilizer is 300:(100 - 200):(300 - 600):(150 - 250):(80 - 120).

7. The preparation method of a soil acidifying and selenium-enriching agent according to claim 2, characterized in that: In the step S4, the inoculation amount of silicate bacteria is 10^8 CFU / g, and the addition amount of the silicate bacteria is 80 - 100 parts.

8. The preparation method of a soil acid-reducing and selenium-enriching modifier according to claim 2, wherein: In the step S5, the addition amount of polyglutamic acid is 80 - 100 parts, the addition amount of small molecule microcarbon is 30 - 50 parts, and the diameter of the dried conditioner particles is 2 - 5 mm.

Images