Red soil dry land multifunctional soil improvement material as well as preparation method and application thereof

Abstract

The invention discloses a multifunctional soil improvement material for red soil dry land as well as a preparation method and application thereof, and belongs to the technical field of soil improvement. The multifunctional soil improvement material for the red soil dry land is prepared from pig manure compost, biochar and calcium-iron hydrotalcite according to the mass ratio of (3-5): (2-4): (2-4), can effectively relieve soil acidification, improve the soil structure, enhance the soil fertility and promote crop growth at the same time in an organic-inorganic composite mode, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement and material preparation, and more particularly to a multifunctional red soil improvement material for dry land, a preparation method and application thereof. Background Art

[0002] Red soil is a typical soil type in southern my country, with a distribution area of 2.18 million km. 2 , accounting for 23% of China's total land area, and plays a vital role in my country's agricultural production. However, due to environmental conditions such as high temperatures and heavy rainfall, as well as various factors affecting the parent material, red soils are generally severely acidified, with high clay content and low organic matter content. In addition, long-term intensive land use has led to deterioration of soil structure, poor water permeability and aeration, and prominent soil compaction problems, resulting in low and unstable crop yields, which seriously restrict the green and high-quality development of regional agriculture.

[0003] At present, the main measures for improving red soil drylands include applying alkaline conditioners such as lime or biochar, planting green manure, increasing the application of organic fertilizer, returning straw to the fields, etc. Although these measures can alleviate acidification, improve soil structure, and increase soil fertility to a certain extent, their functions are relatively single. There is an urgent need for a multifunctional soil improvement material that can simultaneously solve problems such as severe soil acidification, insufficient fertility, and poor structure. Summary of the Invention

[0004] In view of this, the present invention provides a multifunctional soil improvement material for red soil dryland and a preparation method thereof, which can effectively alleviate soil acidification, improve soil structure, enhance soil fertility, promote crop growth, and has broad application prospects.

[0005] To achieve the above object, the present invention adopts the following technical solutions: First, the present invention provides a method for preparing a multifunctional soil improvement material for red soil dryland, comprising the following steps: Step 1: Preparation of pig manure compost The fresh pig manure is aerobically fermented and then air-dried to obtain pig manure compost; Step 2: Preparation of biochar The straw is dried and crushed, and then pyrolyzed and carbonized to obtain biochar; Step 3: Preparation of calcium iron hydrotalcite Mixing calcium salt, iron salt and alkali and performing co-precipitation reaction to obtain calcium iron hydrotalcite; Step 4: Preparation of multifunctional soil improvement materials for red soil drylands The pig manure compost prepared in step one, the biochar prepared in step two, and the calcium iron hydrotalcite prepared in step three are mixed evenly in proportion to obtain a multifunctional soil improvement material for dry red soil.

[0006] Preferably, the aerobic composting fermentation temperature in step 1 is 50-60°C, and the fermentation time is 30-40 days.

[0007] Preferably, the straw in step 2 is corn straw.

[0008] Preferably, the pyrolysis carbonization temperature in step 2 is 450-500° C., the time is 48-50 h, and it is carried out under anaerobic conditions.

[0009] Preferably, the molar ratio of the calcium salt to the iron salt in step 3 is 3:1, and the specific reaction process is: Dissolve the calcium salt and iron salt in water, then slowly add alkali to keep the pH value at 12-13, stir vigorously for 20-30 minutes to mix evenly, then react at 25°C for 20-30 hours, collect the precipitate by filtration, wash with deionized water, and dry at room temperature.

[0010] Preferably, the calcium salt is one or both of calcium chloride and calcium nitrate, the iron salt is one or more of ferric sulfate, ferric nitrate and ferric chloride, and the base is one or more of sodium hydroxide, potassium hydroxide and ammonia water.

[0011] Preferably, in step 4, the mass ratio of pig manure compost: biochar: calcium iron hydrotalcite is 3-5:2-4:2-4.

[0012] The present invention also provides a multifunctional red soil improvement material for dry land prepared by the method described in the above technical solution.

[0013] The present invention also provides a red soil dryland multifunctional soil improvement material prepared by the method described in the above technical solution or the use of the red soil dryland multifunctional soil improvement material described in the above technical solution in reducing soil acidity, improving soil structure and increasing soil fertility.

[0014] It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a multifunctional soil improvement material for dry red soil, a preparation method thereof, and an application thereof, which have the following beneficial effects: The pig manure compost in the present invention is rich in organic matter, which can significantly increase the content of soil organic matter, promote the formation of soil aggregates, and improve soil structure; the surface and interlayer of calcium iron hydrotalcite are rich in hydroxyl groups, which can slowly release hydroxyl groups to achieve long-term acidification. 2+ It can replenish the basic ions lost in the soil; straw biochar contains a large specific surface area, rich alkaline substances and functional groups, which is beneficial to Al 3+It has strong adsorption and fixation capabilities, effectively alleviating soil acidification. Its porous structure also improves soil permeability and water retention. The multifunctional red soil aridland soil improvement material, in the form of an organic-inorganic composite, can simultaneously effectively alleviate soil acidification, improve soil structure, enhance soil fertility, and promote crop growth, promising broad application prospects. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] Example 1 The preparation method of the multifunctional soil improvement material for red soil dry land comprises the following steps: S1. 1 kg of fresh pig manure was aerobically fermented at 50°C for 30 days to produce pig manure compost. S2. 1 kg of corn straw was air-dried, crushed, and anaerobically calcined at 450°C for 48 h to produce corn straw biochar. S3. Dissolve 90 mmol of CaCl₂ and 30 mmol of FeCl₃·6H₂O in 100 ml of water. Slowly add 4 mol / L NaOH solution to the solution, maintaining the pH between 12 and 13. Mix thoroughly by vigorous stirring for 30 minutes. Then, react at 25°C for 24 hours. Collect the precipitate by filtration, wash it 3-4 times with deionized water, and dry it at room temperature to produce calcium iron hydrotalcite. S4. Pig manure compost, corn straw biochar, and calcium iron hydrotalcite were uniformly mixed in a mass ratio of 4:3:3 to prepare a multifunctional soil improvement material for dry red soil.

[0017] Example 2 Application of the multifunctional soil amendment material for dry red soil: During land preparation, the multifunctional soil amendment material prepared in Example 1 was spread on the farmland and mixed evenly with the topsoil. Peanuts were then sown and conventional peanut planting field management measures were followed until the peanuts matured and were harvested. The application rate of the multifunctional soil amendment material for dry red soil was 300 kg / mu, and the application frequency was once a year.

[0018] Example 3 The multifunctional soil amendment material for dry red soil was applied during land preparation. The material was then evenly mixed with the topsoil before peanut sowing. Conventional peanut field management measures were followed until the peanuts matured and were harvested. The application rate was 600 kg / mu, and the application frequency was once a year.

[0019] Comparative Example 1 Compared with Example 1, the difference is that quicklime purchased from the market is selected in steps S3 and S4.

[0020] Comparative Example 2 Compared with Example 2, the difference is that no improved materials were applied before sowing peanuts.

[0021] Comparative Example 3 Compared with Example 3, the difference is that the soil improvement material prepared in Comparative Example 1 is applied before peanut sowing.

[0022] Field trials verifying the effectiveness of soil improvement materials were conducted on red soil dryland in Ji'an, Jiangxi Province. The peanut variety used was Wanhua No. 4. After the peanuts matured, their yield was measured. Soil samples were also collected to determine pH, organic matter content, water-stable aggregates, and bulk density. The results are shown in Table 1.

[0023] Table 1 Effects of soil improvement materials on soil properties and peanut yield As shown in Table 1, the multifunctional red soil arid land soil amendment materials of Examples 2 and 3 significantly increased peanut yields, with peanut yields significantly increasing by 29%-64% compared to Comparative Example 2. They also increased soil pH by 0.52-0.81 units, organic matter by 46%-70%, and water-stable macroaggregates by 14%-20%, while reducing soil bulk density by 9.5%-16%. Example 3 (using calcium-iron hydrotalcite as one of the main raw materials) achieved better soil improvement and peanut yield-increasing effects than Comparative Example 3 (using conventional lime as one of the main raw materials). These test results demonstrate that the multifunctional red soil arid land soil amendment materials of the present invention can simultaneously effectively mitigate soil acidification, improve soil structure, enhance soil fertility, and promote crop growth.

[0024] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a multifunctional soil improvement material for red soil dry land, characterized in that: The following steps are involved: Step 1: Preparation of pig manure compost The fresh pig manure is aerobically fermented and then air-dried to obtain pig manure compost; Step 2: Preparation of biochar The straw is dried and crushed, and then pyrolyzed and carbonized to obtain biochar; Step 3: Preparation of calcium iron hydrotalcite Mixing calcium salt, iron salt and alkali and performing co-precipitation reaction to obtain calcium iron hydrotalcite; Step 4: Preparation of multifunctional soil improvement materials for red soil drylands The pig manure compost prepared in step one, the biochar prepared in step two, and the calcium iron hydrotalcite prepared in step three are mixed evenly in proportion to obtain a multifunctional soil improvement material for dry red soil.

2. The method for preparing a multifunctional soil improvement material for dry red soil according to claim 1, characterized in that: The aerobic composting fermentation temperature in step 1 is 50-60°C, and the fermentation time is 30-40 days.

3. The method for preparing a multifunctional soil improvement material for dry red soil according to claim 1, characterized in that: The straw in step 2 is corn straw.

4. The method for preparing a multifunctional soil improvement material for dry red soil according to claim 1, characterized in that: The pyrolysis carbonization temperature in step 2 is 450-500° C., the time is 48-50 h, and it is carried out under anaerobic conditions.

5. The method for preparing a multifunctional soil improvement material for dry red soil according to claim 1, characterized in that: The molar ratio of calcium salt to iron salt in step 3 is 3:1, and the specific reaction process is: Dissolve the calcium salt and iron salt in water, then slowly add alkali to maintain the pH value at 12-13, vigorously stir for 20-30 minutes to mix evenly, then react at 25°C for 20-30 hours, filter and collect the precipitate, wash with deionized water, and dry at room temperature.

6. The method for preparing a multifunctional soil improvement material for dry red soil according to claim 1 or 5, characterized in that: The calcium salt is one or both of calcium chloride and calcium nitrate, the iron salt is one or more of ferric sulfate, ferric nitrate and ferric chloride, and the alkali is one or more of sodium hydroxide, potassium hydroxide and ammonia water.

7. The method for preparing a multifunctional soil improvement material for red soil dry land according to claim 1, characterized in that: In step 4, the mass ratio of pig manure compost: biochar: calcium iron hydrotalcite is 3-5:2-4:2-4.

8. A multifunctional soil improvement material for dry red soil prepared by the method according to any one of claims 1 to 7.

9. Use of the multifunctional red soil dryland soil improvement material prepared by the method according to any one of claims 1 to 7 or the multifunctional red soil dryland soil improvement material according to claim 8 in reducing soil acidity, improving soil structure, and increasing soil fertility.

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