Coastal saline-alkali soil modifier based on spartina alterniflora and preparation method and application thereof
By preparing a soil conditioner based on Spartina alterniflora for coastal saline-alkali land, the problems of soil organic matter deficiency and low microbial activity in coastal saline-alkali land were solved. It achieved the improvement of soluble organic matter and the rapid degradation of organic pollutants. The conditioner is in a soluble state with diverse molecular composition and can persistently activate microbial activity.
Patent Information
- Application Number
- CN202511788971.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-03-13
AI Technical Summary
Coastal saline-alkali soils are deficient in organic matter, and the microbial community is dominated by salt-tolerant groups. Functional microorganisms are difficult to accumulate, and the soil has a weak ability to purify organic pollutants. Existing soil conditioners may increase salt retention or fail to activate microbial activity in a lasting manner. Furthermore, the invasive plant Spartina alterniflora decomposes slowly, resulting in limited generation of dissolved organic matter.
By simulating geothermal reactions, a coastal saline-alkali land conditioner based on Spartina alterniflora was prepared. Spartina alterniflora was treated with montmorillonite, potassium carbonate solution, etc. in a hydrothermal reactor to prepare lignin-rich soluble organic matter. The pH was adjusted and kaolinite was added. After centrifugation and flocculation, the conditioner was freeze-dried to obtain the conditioner.
It increases the dissolved organic matter content of coastal saline-alkali land, lowers soil pH, recruits beneficial microorganisms, promotes the degradation of organic pollutants, and the amendment is in a dissolved state with diverse molecular composition, thus activating microbial activity for a long time.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of invasive plant resource utilization and saline-alkali land improvement, specifically involving a coastal saline-alkali land conditioner based on Spartina alterniflora, its preparation method and application. Background Technology
[0002] Saline-alkali land improvement is an effective way to expand global high-quality arable land resources and is of strategic significance for ensuring food security and maintaining ecological stability. The restoration of coastal saline-alkali land in densely populated areas not only helps alleviate regional land-population conflicts but also has outstanding value in ensuring a sustainable supply of agricultural products. However, the improvement process of this type of land often faces severe challenges. Taking silt-deposited coastal saline-alkali land as an example, soil organic matter is generally scarce, especially the content of dissolved organic matter, which is severely insufficient and cannot meet the basic needs of plant growth and microbial activity. In addition, the microbial community in this type of soil is dominated by salt-tolerant groups, and functional microorganisms (such as those that promote plant growth and degrade organic pollutants) are difficult to effectively accumulate, further restricting plant development and weakening the soil's ability to purify organic pollutants.
[0003] Existing remediation techniques often involve applying various solid organic materials to improve the environment of coastal saline-alkali farmland and activate microbial activity. However, some solid organic materials may carry salt into the soil, enhancing its retention effect. More importantly, coastal saline-alkali lands typically have high water tables and the soil is in a long-term anaerobic state, resulting in slow conversion of exogenously introduced organic materials and significantly limited rates of dissolved organic matter generation. Consequently, the short-term positive stimulating effects may be limited. Furthermore, solid organic materials immobilize organic pollutants, reducing their bioavailability and making them difficult to degrade effectively. Instead, they may be continuously released into the soil environment as the organic materials gradually mineralize, posing a potential ecological risk.
[0004] Dissolved organic matter (DOC) is a complex mixture of various compounds. In the natural environment, it typically contains thousands to tens of thousands of different molecules, and this extremely high molecular diversity is considered an important material basis for maintaining soil microbial community diversity. However, it is important to clarify that not all DOC components contribute to building a community structure dominated by beneficial microorganisms; some components may even inhibit or toxicize microbial activity. DOC with a single component, due to its resource specificity, often only supports the growth of a limited number of microbial species, making it difficult to achieve broad regulation of the microbial community. While components that are easily decomposed rapidly may stimulate microbial activity in the short term, their effects are not sustainable and cannot support the long-term stability and health of the soil ecosystem. Therefore, developing DOC amendments with specific molecular compositions, long-lasting functions, and the ability to target and regulate beneficial microorganisms, specifically tailored to the unique environment of coastal saline-alkali land, has become a fundamental and highly challenging task in the field of saline-alkali land improvement.
[0005] Coastal saline-alkali areas often face the ecological problem of Spartina alterniflora invasion. Its rapid expansion not only inhibits the normal succession of native vegetation but also leads to the homogenization of ecosystem structure and a significant reduction in biodiversity, posing a continuous threat to the ecological security of coastal wetlands. However, from the perspective of resource cycling, invasive biomass can be regarded as a special organic matter precursor resource. In coastal saline-alkali environments, the natural decomposition rate of Spartina alterniflora residues is slow, making it difficult to effectively release nutrients and posing a risk of releasing salts back into the soil. The dissolved organic matter it generates is limited in both total amount and component activity, and is difficult to precisely control. Therefore, there is an urgent need for an innovative method that can utilize the resource of Spartina alterniflora to directionally prepare highly active dissolved organic matter amendments, simultaneously increasing the content of dissolved organic matter in the soil, regulating pH, recruiting beneficial microorganisms, and promoting the degradation of organic pollutants. Summary of the Invention
[0006] Technical problem solved: This invention provides a coastal saline-alkali land conditioner based on Spartina alterniflora, its preparation method and application. It simulates geothermal reaction, innovates the biomass decomposition and fractionation process of Spartina alterniflora, and prepares a new type of soluble conditioner suitable for coastal saline-alkali land. It reduces soil pH, increases the content of soluble organic matter, increases the proportion of lignin-based soluble organic matter, recruits beneficial microorganisms, and accelerates the degradation of organic pollutants.
[0007] Technical Solution: A method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora, comprising the following steps: Step 1: Washing, drying, and pulverizing Spartina alterniflora plants, mixing with montmorillonite, and then mixing with a solution selected from potassium carbonate solution, potassium formate solution, or a potassium carbonate-potassium formate mixture. The mixture is placed in a hydrothermal reactor and reacted at 180-200℃ for 4-6 hours; Step 2: After the reaction, cooling the reactor to room temperature, removing the solid-liquid mixture, mixing with potassium hydroxide solution, and adjusting the pH to 8-9; Step 3: Shaking the mixture obtained in Step 2 on a shaker to separate the solid and liquid and collect the liquid. Adding kaolinite to the liquid, shaking thoroughly, and then separating the solid and liquid again, collecting the liquid; Step 4: Adding hydrochloric acid solution to the liquid obtained in Step 3 to adjust the pH to 3-4, collecting the flocculent solid by high-speed centrifugation, washing, and freeze-drying to obtain the coastal saline-alkali land conditioner.
[0008] The concentration of the potassium carbonate solution, potassium formate solution, or potassium carbonate-potassium formate mixed solution mentioned in step 1 is 0.1-1 mol / L.
[0009] In step 1, the solid-liquid ratio of Spartina alterniflora to the potassium carbonate solution, potassium formate solution, or potassium carbonate-potassium formate mixture is 200-300 g / L.
[0010] In step 1, the mass mixing ratio of montmorillonite and Spartina alterniflora is 0.05-0.1.
[0011] In step 3, the amount of kaolinite added is 50-100 mg / L.
[0012] A coastal saline-alkali land conditioner is prepared by the above method.
[0013] The aforementioned amendments are in a dissolved state in saline-alkali soil, and lignin compounds are the main components.
[0014] The above-mentioned coastal saline-alkali land conditioner is used in the improvement of coastal saline-alkali land.
[0015] The above application includes mixing the amendment with coastal saline-alkali soil, wherein the amount of amendment applied is 0.5-1.5% of the soil mass.
[0016] Application of coastal saline-alkali soil conditioner in the preparation of compositions for accelerating the degradation of organic pollutants in soil.
[0017] Beneficial effects: (1) The present invention provides a method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora, which simultaneously realizes the resource utilization of the invasive plant Spartina alterniflora and the improvement of coastal saline-alkali land. (2) The present invention provides a method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora, which can prepare a carbon-rich conditioner that is dissolved in saline-alkali land, has a rich diversity of molecular compounds, and a high proportion of lignin compounds. (3) The present invention provides a coastal saline-alkali land conditioner based on Spartina alterniflora, which increases dissolved organic carbon, lowers pH, recruits beneficial microorganisms, and accelerates the degradation of organic pollutants. Attached Figure Description
[0018] Figure 1 The elemental composition of the modifier prepared in Example 1.
[0019] Figure 2 The effects of the amendment prepared in Example 1 on the pH, dissolved organic matter content, and proportion of dissolved organic matter in coastal saline-alkali soil. Among them, (1) is the effect of the amendment on the pH of coastal saline-alkali soil, (2) is the effect of the amendment on the dissolved organic matter content, and (3) is the effect of the amendment on the dissolved organic matter and its proportion.
[0020] Figure 3 The effect of the amendment prepared in Example 1 on the bacterial microbial community structure of coastal saline-alkali soil.
[0021] Figure 4 The effect of the amendment prepared in Example 1 on the content of organic pollutants in coastal saline-alkali soil. Detailed Implementation
[0022] The present invention will be further described below with reference to specific embodiments.
[0023] Example 1
[0024] This embodiment provides a method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora and the prepared conditioner, specifically including the following steps:
[0025] Step 1: Clean the Spartina alterniflora plants, dry and crush them, mix them with montmorillonite (mass ratio of Spartina alterniflora to Spartina alterniflora is 0.08), and then mix them with potassium carbonate solution (0.5 mol / L) (250 g / L). Place the mixture in a hydrothermal reactor and react it under medium temperature conditions (180℃, 5 h).
[0026] Step 2: After the reaction is complete, the reaction vessel is cooled to room temperature, the solid-liquid mixture is removed, mixed with potassium hydroxide solution, and the pH is adjusted to 8.
[0027] Step 3: Shake the mixed solution on a shaker to separate the solid and liquid and collect the liquid. Add kaolinite to the liquid solution (80 mg / L), shake thoroughly to separate the solid and liquid, and remove the liquid.
[0028] Step 4: Add hydrochloric acid solution to the collected liquid and adjust the pH to 3. Collect the flocculent solid by high-speed centrifugation and freeze-dry to obtain the coastal saline-alkali land conditioner.
[0029] Results analysis:
[0030] Figure 1 This describes the elemental composition of the modifier prepared in this embodiment. The contents of C, H, O, N, and S are 69.22%, 6.02%, 19.36%, 2.28%, and 0.82%, respectively. Subtraction analysis reveals that its ash content is only 2.3%. This indicates that this modifier has high carbon, high oxygen, and high nitrogen content, and high purity. The low ash content indicates that the method of this invention can purify most of the metal salt ions in the Spartina alterniflora plant.
[0031] Example 2
[0032] This embodiment provides a method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora and the prepared conditioner, specifically including the following steps:
[0033] Step 1: Clean the Spartina alterniflora plants, dry and crush them, mix them with montmorillonite (mass ratio of Spartina alterniflora to Spartina alterniflora is 0.08), and then mix them with potassium carbonate solution (0.1 mol / L) (200 g / L). Place the mixture in a hydrothermal reactor and react it under medium temperature conditions (180℃, 4 h).
[0034] Step 2: After the reaction is complete, the reaction vessel is cooled to room temperature, the solid-liquid mixture is removed, mixed with potassium hydroxide solution, and the pH is adjusted to 8.
[0035] Step 3: Shake the mixed solution on a shaker to separate the solid and liquid and collect the liquid. Add kaolinite to the liquid solution (50 mg / L), shake thoroughly to separate the solid and liquid, and remove the liquid.
[0036] Step 4: Add hydrochloric acid solution to the collected liquid and adjust the pH to 3. Collect the flocculent solid by high-speed centrifugation and freeze-dry to obtain the coastal saline-alkali land conditioner.
[0037] Example 3
[0038] This embodiment provides a method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora and the prepared conditioner, specifically including the following steps:
[0039] Step 1: Clean the Spartina alterniflora plants, dry and crush them, mix them with montmorillonite (mass ratio of Spartina alterniflora to Spartina alterniflora is 0.08), and then mix them with potassium carbonate solution (1 mol / L) (300 g / L). Place the mixture in a hydrothermal reactor and react it under medium temperature conditions (180℃, 6 h).
[0040] Step 2: After the reaction is complete, the reaction vessel is cooled to room temperature, the solid-liquid mixture is removed, mixed with potassium hydroxide solution, and the pH is adjusted to 8.
[0041] Step 3: Shake the mixed solution on a shaker to separate the solid and liquid and collect the liquid. Add kaolinite to the liquid solution (100 mg / L), shake thoroughly to separate the solid and liquid, and remove the liquid.
[0042] Step 4: Add hydrochloric acid solution to the collected liquid and adjust the pH to 3. Collect the flocculent solid by high-speed centrifugation and freeze-dry to obtain the coastal saline-alkali land conditioner.
[0043] Example 4
[0044] This embodiment provides a method for preparing a soil conditioner based on Spartina alterniflora for improving coastal saline-alkali land. The application of this conditioner in improving coastal saline-alkali land soil is specifically demonstrated using the material prepared in Example 1. The specific steps are as follows: 200 g of air-dried coastal saline-alkali land soil is placed in a petri dish, and 1.5% (by mass) of the conditioner is added. Water is added to 60% of the field capacity. The dish is then incubated in an incubator, and samples are taken at intervals to measure pH, dissolved organic carbon, and bacterial community structure.
[0045] Results analysis:
[0046] Figure 2 This study describes the effects of the soil conditioner prepared in Example 1 on the pH, dissolved organic matter content, and proportion of dissolved organic matter in coastal saline-alkali soil under the conditions described in Example 4. The original soil pH was 8.61. After applying the conditioner, the pH significantly decreased and remained at 7.15. The original dissolved organic matter content was 55.33 mg / kg. After applying the conditioner, its content significantly increased, reaching an increase of 1165%. After 8 weeks, the dissolved organic matter content was still as high as 295.12 mg / kg. From a component perspective, after the addition of the conditioner, the dissolved organic matter in the saline-alkali soil was mainly composed of lignin, with its proportion increasing from 61% to over 90%, and this level was maintained for more than 8 weeks.
[0047] Figure 3The effect of the soil conditioner prepared in Example 1 on the bacterial microbial community structure of coastal saline-alkali soil under the operation in Example 4. Under salt stress, the dominant bacterial genera in the soil were Pontibacter (11.35%), Fictibacillus (11.26%), Mesobacillus (9.22%), Neobacillus (3.51%), Rossellomorea (2.36%), Sphingomonas (4.19%), and Bacillus (3.16%). Coastal saline-alkali soil is a typical stress environment. Under this environment, bacterial genera with stress resistance (such as high salt and nutrient deficiency), such as Pontibacter and Fictibacillus, were selected and became the dominant bacterial groups. Their high relative abundance is microbiological evidence of the high stress characteristics of this soil. After the application of the soil conditioner, the dominant bacterial genera shifted to Priestia (27.68%), Streptomyces (8.66%), Bacillus (8.29%), Rossellomorea (5.96%), Peribacillus (5.31%), Pseudomonas (4.16%), and Metabacillus (3.72%). Due to the improved soil habitat (e.g., decreased pH and increased dissolved organic matter), the relative abundance of genera such as Pontibacter, adapted to the original high-stress environment, decreased significantly, while a more diverse range of rare genera became enriched. Among these, Priestia, Streptomyces, Bacillus, Rossellomorea, and Peribacillus are typical beneficial microbial genera in soil, especially Priestia, which is often considered a core genera in microbial fertilizers. Streptomyces and Bacillus are genera that efficiently degrade common organic pollutants in soil. The significant increase in the relative abundance of these beneficial bacteria can enhance the activation and cycling of nutrients in saline-alkali land, reduce organic pollutants, promote plant growth, and enhance biological control, laying the foundation for sustained high and stable yields in coastal saline-alkali farmland.
[0048] Example 5
[0049] This embodiment provides an application of a method for preparing a soil conditioner based on Spartina alterniflora for coastal saline-alkali land, specifically using the conditioner prepared in Example 1. The specific steps are as follows: 180 g of air-dried coastal saline-alkali soil is placed in a petri dish and mixed with 20 g of contaminated soil to prepare organic-contaminated soil. A conditioner at a mass ratio of 0.5% is added, and water is added to 60% of field capacity. The mixture is incubated for 7 days, and the concentration of organic pollutants is sampled and measured.
[0050] Results analysis:
[0051] Figure 4 This describes the effect of the amendment prepared in Example 1 on the content of organic pollutants in coastal saline-alkali soil under the operation in Example 5. After 7 days of amendment addition, compared with the control, the content of plasticizer di(2-ethylhexyl) phthalate (DEHP) decreased by 91.25%, and the content of dibutyl phthalate (DBP) decreased by 92.10%.
[0052] The present invention has been described in detail above with reference to specific exemplary embodiments. However, it should be understood that various modifications and variations can be made without departing from the scope of the invention as defined by the appended claims. The detailed description and drawings should be considered illustrative only and not restrictive, and any such modifications and variations shall fall within the scope of the invention described herein. Furthermore, the background art is intended to illustrate the current state of development and significance of the technology and is not intended to limit the present invention or its application areas.
Claims
1. A method for preparing a coastal saline-alkali land conditioner based on Spartina alterniflora, characterized in that, The process includes the following steps: Step 1: Wash, dry, and crush Spartina alterniflora plants, mix with montmorillonite, and then mix with a solution selected from potassium carbonate solution, potassium formate solution, or a potassium carbonate-potassium formate mixture. Place the mixture in a hydrothermal reactor and react at 180-200℃ for 4-6 hours; Step 2: After the reaction, cool the reactor to room temperature, remove the solid-liquid mixture, mix with potassium hydroxide solution, and adjust the pH to 8-9; Step 3: Shake the mixture obtained in Step 2 on a shaker to separate the solid and liquid and collect the liquid. Add kaolinite to the liquid, shake thoroughly, and then separate the solid and liquid again, removing the liquid; Step 4: Add hydrochloric acid solution to the liquid obtained in Step 3 to adjust the pH to 3-4. Centrifuge at high speed to collect the flocculent solid, wash, and freeze-dry to obtain the coastal saline-alkali land conditioner.
2. The preparation method according to claim 1, characterized in that, The concentration of the potassium carbonate solution, potassium formate solution, or potassium carbonate-potassium formate mixed solution mentioned in step 1 is 0.1-1 mol / L.
3. The preparation method according to claim 1, characterized in that, In step 1, the solid-liquid ratio of Spartina alterniflora to the potassium carbonate solution, potassium formate solution, or potassium carbonate-potassium formate mixture is 200-300 g / L.
4. The preparation method according to claim 1, characterized in that, In step 1, the mass mixing ratio of montmorillonite and Spartina alterniflora is 0.05-0.
1.
5. The preparation method according to claim 1, characterized in that, In step 3, the amount of kaolinite added is 50-100 mg / L.
6. A coastal saline-alkali land conditioner, characterized in that, It is prepared by the method described in any one of claims 1-5.
7. The coastal saline-alkali land conditioner according to claim 6, characterized in that, The improver is in a dissolved state in saline-alkali soil, and lignin compounds are the main components.
8. The application of the coastal saline-alkali land conditioner according to claim 6 in the improvement of coastal saline-alkali land.
9. The application according to claim 8, characterized in that, The application involves mixing the amendment with coastal saline-alkali soil, with the amount of amendment applied being 0.5-1.5% of the soil mass.
10. The use of the coastal saline-alkali land conditioner of claim 6 in the preparation of compositions for accelerating the degradation of organic pollutants in soil.