Soil improvement method for mangrove forest sapling planting

Abstract

The invention relates to the technical field of soil improvement, in particular to a soil improvement method for mangrove tree seedling planting, which is used for solving the problem that the survival rate and preservation rate of mangrove tree seedlings are low due to the fact that existing soil for mangrove tree seedling planting is too high in salinity or lacks necessary nutrients. Organic matters are added to slowly decompose and release to provide nutrients, a soil conditioner and the organic matters are added, ions and microorganisms are adsorbed and slowly released through a network structure to promote nutrient activation and circulation, continuous and balanced nutrient release is provided, and the long-term growth requirement of the saplings is met; a microbial agent is applied to inhibit soil-borne pathogenic bacteria and reduce the incidence rate of root system diseases; salt stress and pH fluctuation are effectively buffered, relatively mild conditions are created for survival of the saplings in a mud flat high-salt and weak-base environment, the improved soil is loose, breathable and not hardened, meanwhile, the soil has excellent water and fertilizer retention capacity and can resist tidal scour and prevent lodging of the saplings, and the survival rate and preservation rate of the mangrove forest saplings are increased.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, specifically to a soil improvement method for planting mangrove seedlings. Background Technology

[0002] Soil improvement technology plays a vital role in enhancing land productivity and protecting the ecological environment. Mangroves, due to their unique ecosystem functions, play an indispensable role in windbreak and soil stabilization, water purification, and maintaining biodiversity. The planting of mangrove seedlings has high environmental requirements, and suitable soil conditions are one of the key factors for their healthy growth.

[0003] Traditional soil improvement methods mainly rely on chemical fertilizers and pesticides. While these methods can improve soil fertility and suppress pests and diseases in the short term, they also lead to long-term soil degradation and environmental pollution. Mangroves are a special plant community that grows in the intertidal zone, including species such as mangroves, white mangroves, and tung trees. These plants have special adaptation mechanisms that can resist seawater corrosion and extremely high salinity. However, due to excessive soil salinity or lack of necessary nutrients, the survival rate and retention rate of mangrove seedlings are low.

[0004] In view of the above-mentioned technical defects, the soil improvement method for planting mangrove seedlings proposed in this invention is of great significance in the field of soil improvement technology. Summary of the Invention

[0005] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a soil improvement method for planting mangrove seedlings, which solves the problem that the soil salinity is too high or the lack of necessary nutrients in the existing mangrove seedling planting, resulting in low survival rate and preservation rate of mangrove seedlings.

[0006] The objective of this invention can be achieved through the following technical solutions: This application provides a soil improvement method for planting mangrove seedlings, comprising the following steps: Soil for planting mangrove seedlings is mixed with soil conditioner, organic matter and functional filler to obtain mixed soil; after 48-72 hours, microbial inoculants are applied to the mixed soil and dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0007] In a preferred embodiment of the present invention, the weight ratio of the soil, soil conditioner, organic matter, functional filler and microbial agent used for planting mangrove seedlings is 10:0.05-0.08:1-1.5:0.5-1:0.02-0.025.

[0008] In a preferred embodiment of the present invention, the functional filler is one or more of the following: shell fragments, coarse sand, and wood chips.

[0009] In a preferred embodiment of the present invention, the microbial agent is a salt- and alkali-tolerant plant rhizosphere growth-promoting agent with an effective viable count of 2.0 × 10⁻⁶ bacteria. 9 CFU / g, the bacterial species are one or more combinations of Bacillus licheniformis, Bacillus megaterium, and gelatinous spore-forming bacteria.

[0010] In a preferred embodiment of the present invention, the soil conditioner is prepared by the following steps: Step a1: Add carboxymethyl cellulose and deionized water to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 35℃ and 1500 r / min for 10-12 h. Add sodium periodate solution and adjust the pH to 3-4 with sulfuric acid solution. Mix and stir in the dark for 4-5 h. Precipitate with anhydrous ethanol, wash 2-3 times, and freeze-dry at -50℃ for 24 h to obtain the intermediate product. Add berberine hydrochloride and 2,4-dimethoxybenzylamine to a beaker. Mix and stir at 120℃ and 1500 r / min for 6-8 h. Cool naturally to 25℃, wash 1-2 times with acetone, and freeze-dry at -50℃ for 24 h. Add methanol and concentrated hydrochloric acid solution, mix and stir at 25℃ for 4-6 h, filter, wash the filter cake 2-3 times with ethanol solution, and freeze-dry at -50℃ for 24 h to obtain modified carboxymethyl cellulose. Step a2: Add the intermediate product, modified carboxymethyl cellulose and deionized water to a three-necked flask equipped with a stirrer and thermometer. Adjust the pH to 4-6 with a pH adjuster. Mix and stir at 30-50℃ and 1500r / min for 12h. Dialyze at a molecular weight cutoff of 3500-5000 for 72h. Freeze-dry at -50℃ for 24h to obtain modified carboxymethyl cellulose. Step a3: Add clay minerals and deionized water to a beaker and mix for 30 minutes to obtain a suspension; add the suspension and modified carboxymethyl cellulose to a three-necked flask equipped with a stirrer and thermometer, mix and stir for 1-2 hours, transfer to a centrifuge, centrifuge at 8000-8500g to degas for 15 minutes, add crosslinking agent, mix and stir at 25℃ for 30 minutes, heat in a water bath at 60℃ for 30 minutes, put into fermentation broth, vacuum impregnate at -0.085MPa for 30 minutes, freeze dry at -50℃ for 24 hours, add sodium alginate and calcium chloride solution, solidify reaction for 12 hours, wash with distilled water 2-3 times, dry at 40-50℃ for 3-4 hours to obtain soil conditioner.

[0011] In a preferred embodiment of the present invention, the ratio of carboxymethyl cellulose, deionized water, sodium periodate solution, berberine hydrochloride, 2,4-dimethoxybenzylamine, methanol, and concentrated hydrochloric acid solution in step a1 is 1-2g: 20-40mL: 10-20mL: 7-8g: 15-20mL: 30-50mL: 10-15mL; the carboxymethyl cellulose is one of carboxymethyl cellulose ammonium, carboxymethyl cellulose sodium, and carboxymethyl cellulose potassium; the concentration of the sodium periodate solution is 0.11g / mL; the concentration of the sulfuric acid solution is 1mol / L; the mass fraction of the concentrated hydrochloric acid is 36-38%; and the mass fraction of the ethanol solution is 80%.

[0012] In a preferred embodiment of the present invention, the ratio of the intermediate product, modified carboxymethyl cellulose and deionized water in step a2 is 0.1-0.2g:0.5-1g:20-40mL; the pH adjuster is 0.1-0.5mol / L acetate-sodium acetate buffer solution.

[0013] In a preferred embodiment of the present invention, the ratio of clay mineral, deionized water, modified carboxymethyl cellulose, crosslinking agent, sodium alginate, and calcium chloride solution in step a3 is 10-15g:100mL:2-3g:1-1.5g:0.3-0.5g:50-100mL; the clay mineral is one or more combinations of halloysite, laterite, and kaolin; the crosslinking agent is epichlorohydrin; the mass fraction of the calcium chloride solution is 2%; and the fermentation broth is γ-polyglutamic acid fermentation broth.

[0014] In a preferred embodiment of the present invention, the organic matter is prepared by the following steps: The straw was washed 1-2 times with distilled water, dried at 60-70℃ for 1-2 hours, crushed and sieved through a 40-mesh sieve, and then placed in a ceramic crucible for pyrolysis in a box furnace. The heating rate was set at 10℃ / min, and the temperature was raised to 300-500℃ and then kept constant for 2 hours. After natural cooling to 25℃, the straw was placed in an Erlenmeyer flask, phosphoric acid solution was added, and the mixture was stirred for 10-12 hours. The straw was washed 2-3 times with distilled water and dried at 50-60℃ for 2-3 hours to obtain an intermediate product. Zero-valent iron nanoparticles and the intermediate product were added to a beaker, stirred for 1-2 hours, and ball-milled in a planetary ball mill with a ball-to-material ratio of 10-15:1 using agate beads as the ball milling medium and nitrogen protection. The mixture was ball-milled at 300 r / min for 8-10 hours to obtain organic matter.

[0015] In a preferred embodiment of the present invention, the ratio of straw, phosphoric acid solution and zero-valent iron nanoparticles is 5-10g: 50-70mL: 10-20g; the straw is one of corn straw, soybean straw and rice straw; and the mass fraction of the sulfuric acid solution is 50%.

[0016] The beneficial effects of this invention are: This invention discloses a soil improvement method for planting mangrove seedlings. The method involves mixing soil intended for mangrove seedling planting with a soil conditioner, organic matter, and functional fillers to obtain mixed soil. After 48-72 hours, a microbial agent is applied to the mixed soil, followed by drying to obtain improved soil for mangrove seedling planting. The improved soil is loose, breathable, and does not compact, while possessing excellent water and fertilizer retention capacity. It can resist tidal erosion and prevent seedling lodging. Organic matter slowly decomposes and releases nutrients, the network structure of the soil conditioner adsorbs and slowly releases ions, and microbial activity promotes nutrient activation and cycling, providing continuous and balanced nutrient release to meet the long-term growth needs of the seedlings. Beneficial microorganisms dominate in the soil, inhibiting soil-borne pathogens and reducing the incidence of root diseases. It effectively buffers salt stress and pH fluctuations, creating mild conditions for seedling survival in the high-salt, slightly alkaline environment of tidal flats.

[0017] In the process of improving the soil for planting mangrove seedlings, a soil conditioner was first prepared. Sodium periodate cleaved the -CH2OH-CH2OH- bond on the sugar ring of carboxymethyl cellulose, oxidizing the two hydroxyl groups to two aldehyde groups, yielding an intermediate product. The methoxy group of berberine hydrochloride and the amino group of 2,4-dimethoxybenzylamine underwent nucleophilic substitution upon heating, introducing a primary amine group into the molecule. The aldehyde group on the intermediate product reacted with the primary amine group on the aminated berberine to form a C=N double bond, covalently linking berberine to the carboxymethyl cellulose backbone. The antibacterial molecule berberine, linked by strong chemical bonds, slowly hydrolyzes and releases under soil moisture, preventing rapid loss and achieving long-lasting antibacterial activity. It inhibits soil-borne pathogens such as root rot and damping-off common in mangrove seedlings, and is also environmentally friendly to non-target organisms. Epichlorohydrin undergoes ring-opening polymerization with the modified carboxymethyl cellulose and the hydroxyl groups on the surface of clay minerals to form a stable three-dimensional organic compound. - An inorganic hybrid network, using vacuum negative pressure, draws the active ingredients from the γ-polyglutamic acid fermentation broth into the material's pores; freeze-drying fixes this structure, forming a porous carrier. The outermost layer, sodium alginate, forms a hydrogel coating with calcium ions. This three-dimensional network and porous structure adsorb water and nutrient ions, releasing them through the shell, effectively combating nutrient loss caused by tidal erosion and rapid soil water loss after low tide, providing seedlings with a continuous and stable supply of water and fertilizer, and improving survival rate. γ-polyglutamic acid can encapsulate sodium ions, reducing salt toxicity. Its excellent water retention capacity dilutes rhizosphere salt concentration. Seashell fragments and other fillers slowly release calcium ions to antagonize sodium ion absorption and stabilize pH, enhancing colonization ability. γ-polyglutamic acid is a highly efficient root growth stimulant. The porous structure provides a habitat for beneficial microorganisms, stimulating seedling root growth, enhancing anchoring and absorption capacity, while simultaneously cultivating rhizosphere microbial communities, forming a virtuous cycle, and fundamentally improving soil ecology.

[0018] In the process of improving soil for mangrove seedling cultivation, organic matter was first prepared. Straw underwent thermal decomposition at high temperatures, releasing volatile substances to form crude biochar rich in a carbon skeleton. Phosphoric acid, acting as an activator, reacted with hydroxyl groups and other groups in the biomass under heating, promoting dehydration, forming cross-linked ester structures, and creating pores; increasing specific surface area and porosity, and introducing phosphorus- and gas-containing acidic functional groups; through the mechanical force of high-intensity ball milling, zero-valent iron nanoparticles were physically embedded and firmly attached to the pores and surface of the biochar, forming a composite material; endowing the biochar with strong reducing properties, magnetism, and additional adsorption sites; the porous carbon skeleton adsorbs heavy metal ions, Organic pollutants, such as Cr and As, are reduced to less toxic forms by zero-valent iron and co-precipitated as oxides, effectively passivating pollution in mangrove tidal flats and creating a cleaner and safer growth environment for seedling roots, thus reducing the risk of toxicity. The high specific surface area and porous structure effectively lock in water and nutrient molecules, preventing tidal erosion. As a skeletal material, it reduces soil compaction and increases permeability. In synergy with functional fillers, it improves soil structure, provides long-lasting water and fertilizer retention, and its surface functional groups such as phosphate can gently regulate the pH of alkaline tidal flat soils. The porous structure provides a habitat and protection for beneficial bacteria in microbial agents, extending their survival and efficacy. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram showing the test results of the survival rate and preservation rate of mangrove seedlings planted in improved soil in Examples 1-3 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: This embodiment describes a soil improvement method for planting mangrove seedlings, comprising the following steps: Step S1: Add 1g of carboxymethyl cellulose ammonium and 20mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Mix and stir for 10h at 35℃ and 1500r / min. Add 10mL of 0.11g / mL sodium periodate solution, adjust the pH to 3 with 1mol / L sulfuric acid solution, and mix and stir in the dark for 4h. Precipitate with anhydrous ethanol, wash twice, and freeze-dry at -50℃ for 24h to obtain the intermediate product. Add 7g of berberine hydrochloride and 15mL of... 2,4-Dimethoxybenzylamine was added to a beaker and mixed and stirred at 120℃ and 1500 r / min for 6 h. After naturally cooling to 25℃, it was washed once with acetone and freeze-dried at -50℃ for 24 h. Then, 30 mL of methanol and 10 mL of 36% hydrochloric acid solution were added and mixed and stirred at 25℃ for 4 h. The mixture was filtered, and the filter cake was washed twice with 80% ethanol solution and freeze-dried at -50℃ for 24 h to obtain modified carboxymethyl cellulose. Step S2: Add 0.1g of intermediate product, 0.5g of modified carboxymethyl cellulose and 20mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Adjust the pH to 4 with 0.1mol / L acetate-sodium acetate buffer. Mix and stir at 30℃ and 1500r / min for 12h. Dialyze at a molecular weight cutoff of 3500 for 72h. Freeze-dry at -50℃ for 24h to obtain modified carboxymethyl cellulose. Step S3: Add 10g halloysite and 100mL deionized water to a beaker and mix for 30min to obtain a suspension; add the suspension and 2g modified carboxymethyl cellulose to a three-necked flask equipped with a stirrer and thermometer, mix and stir for 1h, transfer to a centrifuge, centrifuge at 8000g to degas for 15min, add 1g epichlorohydrin, mix and stir at 25℃ for 30min, heat in a water bath at 60℃ for 30min, put into γ-polyglutamic acid fermentation broth, vacuum impregnate at -0.085MPa for 30min, freeze dry at -50℃ for 24h, add 0.3g sodium alginate and 50mL of 2% calcium chloride solution, solidify for 12h, wash twice with distilled water, and dry at 40℃ for 3h to obtain the soil conditioner; Step S4: Wash 5g of rice straw once with distilled water, dry it at 60℃ for 1h, crush it and sieve it through a 40-mesh sieve, put it into a ceramic crucible, place it in a box furnace for pyrolysis, set the heating rate to 10℃ / min, heat it to 300℃ and then keep it at a constant temperature for 2h, cool it naturally to 25℃, put it into a conical flask, add 50mL of 50% phosphoric acid solution, mix and stir for 10h, wash it twice with distilled water, dry it at 50℃ for 2h to obtain an intermediate product; add 10g of zero-valent iron nanoparticles and the intermediate product into a beaker, mix and stir for 1h, use agate beads as the ball milling medium, the ball-to-material ratio is 10:1, place it in a planetary ball mill, purge with nitrogen protection, and ball mill at 300r / min for 8h to obtain organic matter; Step S5: Mix 10 parts of soil for planting mangrove seedlings with 0.05 parts of soil conditioner, 1 part of organic matter, and 0.5 parts of shell fragments to obtain mixed soil; apply 0.02 parts of a fungicide with an effective viable bacteria count of 2.0 × 10⁻⁶ to the above mixed soil. 9 CFU / g of Bacillus licheniformis was dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0023] Example 2: This embodiment describes a soil improvement method for planting mangrove seedlings, comprising the following steps: Step S1: Add 1.5g of carboxymethyl cellulose ammonium and 30mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 35℃ and 1500r / min for 11h. Add 15mL of 0.11g / mL sodium periodate solution, adjust the pH to 3.5 with 1mol / L sulfuric acid solution, and mix and stir in the dark for 4.5h. Precipitate with anhydrous ethanol, wash three times, and freeze-dry at -50℃ for 24h to obtain the intermediate product. Add 7.5g of berberine hydrochloride and 18mL of... 2,4-Dimethoxybenzylamine was added to a beaker and mixed and stirred at 120℃ and 1500 r / min for 7 h. After naturally cooling to 25℃, the mixture was washed twice with acetone and freeze-dried at -50℃ for 24 h. 40 mL of methanol and 13 mL of 37% hydrochloric acid solution were added and mixed and stirred at 25℃ for 5 h. The mixture was then filtered, and the filter cake was washed three times with 80% ethanol solution and freeze-dried at -50℃ for 24 h to obtain modified carboxymethyl cellulose. Step S2: Add 0.15g of intermediate product, 0.8g of modified carboxymethyl cellulose and 30mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Adjust the pH to 4.5 with 0.3mol / L acetate-sodium acetate buffer. Mix and stir at 40℃ and 1500r / min for 12h. Dialyze at a molecular weight cutoff of 4000 for 72h. Freeze-dry at -50℃ for 24h to obtain modified carboxymethyl cellulose. Step S3: Add 13g halloysite and 100mL deionized water to a beaker and mix for 30min to obtain a suspension; add the suspension and 2.5g modified carboxymethyl cellulose to a three-necked flask equipped with a stirrer and thermometer, mix and stir for 1.5h, transfer to a centrifuge, centrifuge at 8300g to degas for 15min, add 1.3g epichlorohydrin, mix and stir at 25℃ for 30min, heat in a water bath at 60℃ for 30min, put into γ-polyglutamic acid fermentation broth, vacuum impregnate at -0.085MPa for 30min, freeze dry at -50℃ for 24h, add 0.4g sodium alginate and 75mL of 2% calcium chloride solution, solidify for 12h, wash 3 times with distilled water, and dry at 45℃ for 3.5h to obtain the soil conditioner; Step S4: Wash 8g of rice straw twice with distilled water, dry at 65℃ for 1.5h, crush and sieve through a 40-mesh sieve, place in a ceramic crucible, and pyrolyze in a box furnace. Set the heating rate to 10℃ / min, heat to 400℃ and then pyrolyze at a constant temperature for 2h. Allow to cool naturally to 25℃, place in a conical flask, add 60mL of 50% phosphoric acid solution, mix and stir for 11h, wash three times with distilled water, and dry at 55℃ for 2.5h to obtain an intermediate product. Add 15g of zero-valent iron nanoparticles and the intermediate product to a beaker, mix and stir for 1.5h, use agate beads as the ball milling medium, with a ball-to-material ratio of 13:1, place in a planetary ball mill, purge with nitrogen protection, and ball mill at 300r / min for 9h to obtain organic matter. Step S5: Mix 10 parts of soil for planting mangrove seedlings with 0.07 parts of soil conditioner, 1.3 parts of organic matter, and 0.8 parts of shell fragments to obtain mixed soil; apply 0.023 parts of a fungicide with an effective viable bacteria count of 2.0 × 10⁻⁶ to the mixed soil. 9 CFU / g of Bacillus licheniformis was dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0024] Example 3: This embodiment describes a soil improvement method for planting mangrove seedlings, comprising the following steps: Step S1: Add 2g of carboxymethyl cellulose ammonium and 40mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Mix and stir for 12h at 35℃ and 1500r / min. Add 20mL of 0.11g / mL sodium periodate solution, adjust the pH to 4 with 1mol / L sulfuric acid solution, and mix and stir in the dark for 5h. Precipitate with anhydrous ethanol, wash 3 times, and freeze-dry at -50℃ for 24h to obtain the intermediate product. Add 8g of berberine hydrochloride and 20mL of... 2,4-Dimethoxybenzylamine was added to a beaker and mixed and stirred at 120℃ and 1500 r / min for 8 h. After naturally cooling to 25℃, the mixture was washed twice with acetone and freeze-dried at -50℃ for 24 h. 50 mL of methanol and 15 mL of 38% hydrochloric acid solution were added and mixed and stirred at 25℃ for 6 h. The mixture was then filtered, and the filter cake was washed three times with 80% ethanol solution and freeze-dried at -50℃ for 24 h to obtain modified carboxymethyl cellulose. Step S2: Add 0.2g of intermediate product, 1g of modified carboxymethyl cellulose and 40mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Adjust the pH to 6 with 0.5mol / L acetate-sodium acetate buffer solution. Mix and stir at 50℃ and 1500r / min for 12h. Dialyze at a molecular weight cutoff of 5000 for 72h. Freeze-dry at -50℃ for 24h to obtain modified carboxymethyl cellulose. Step S3: Add 15g halloysite and 100mL deionized water to a beaker and mix for 30min to obtain a suspension; add the suspension and 3g modified carboxymethyl cellulose to a three-necked flask equipped with a stirrer and thermometer, mix and stir for 2h, transfer to a centrifuge, centrifuge at 8500g to degas for 15min, add 1.5g epichlorohydrin, mix and stir at 25℃ for 30min, heat in a water bath at 60℃ for 30min, put into γ-polyglutamic acid fermentation broth, vacuum impregnate at -0.085MPa for 30min, freeze dry at -50℃ for 24h, add 0.5g sodium alginate and 100mL of 2% calcium chloride solution, solidify for 12h, wash 3 times with distilled water, dry at 50℃ for 4h to obtain soil conditioner; Step S4: Wash 10g of rice straw twice with distilled water, dry it at 70℃ for 2h, crush it and sieve it through a 40-mesh sieve, put it into a ceramic crucible, place it in a box furnace for pyrolysis, set the heating rate to 10℃ / min, heat it to 500℃ and then keep it at a constant temperature for 2h, cool it naturally to 25℃, put it into a conical flask, add 70mL of 50% phosphoric acid solution, mix and stir for 12h, wash it three times with distilled water, dry it at 60℃ for 3h to obtain an intermediate product; add 20g of zero-valent iron nanoparticles and the intermediate product into a beaker, mix and stir for 2h, use agate beads as the ball milling medium, the ball-to-material ratio is 15:1, place it in a planetary ball mill, purge with nitrogen protection, and ball mill at 300r / min for 10h to obtain organic matter; Step S5: Mix 10 parts of soil for planting mangrove seedlings with 0.08 parts of soil conditioner, 1.5 parts of organic matter, and 1 part of shell fragments to obtain mixed soil; apply 0.025 parts of a fungicide with an effective viable bacteria count of 2.0 × 10⁻⁶ to the above mixed soil. 9 CFU / g of Bacillus licheniformis was dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0025] Comparative Example 1: This comparative example illustrates a soil improvement method for planting mangrove seedlings, comprising the following steps: Step S1: Mix 10 parts of soil for planting mangrove seedlings with 1.3 parts of rice straw and 0.8 parts of shell fragments to obtain mixed soil; apply 0.023 parts of a fungicide with an effective viable bacteria count of 2.0 × 10⁻⁶ to the above mixed soil. 9 CFU / g of Bacillus licheniformis was dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0026] Comparative Example 2: This comparative example illustrates a soil improvement method for planting mangrove seedlings, comprising the following steps: Step S1: Add 1.5g of carboxymethyl cellulose ammonium and 30mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Mix and stir at 35℃ and 1500r / min for 11h. Add 15mL of 0.11g / mL sodium periodate solution, adjust the pH to 3.5 with 1mol / L sulfuric acid solution, and mix and stir in the dark for 4.5h. Precipitate with anhydrous ethanol, wash three times, and freeze-dry at -50℃ for 24h to obtain the intermediate product. Add 7.5g of berberine hydrochloride and 18mL of... 2,4-Dimethoxybenzylamine was added to a beaker and mixed and stirred at 120℃ and 1500 r / min for 7 h. After naturally cooling to 25℃, the mixture was washed twice with acetone and freeze-dried at -50℃ for 24 h. 40 mL of methanol and 13 mL of 37% hydrochloric acid solution were added and mixed and stirred at 25℃ for 5 h. The mixture was then filtered, and the filter cake was washed three times with 80% ethanol solution and freeze-dried at -50℃ for 24 h to obtain modified carboxymethyl cellulose. Step S2: Add 0.15g of intermediate product, 0.8g of modified carboxymethyl cellulose and 30mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Adjust the pH to 4.5 with 0.3mol / L acetate-sodium acetate buffer. Mix and stir at 40℃ and 1500r / min for 12h. Dialyze at a molecular weight cutoff of 4000 for 72h. Freeze-dry at -50℃ for 24h to obtain modified carboxymethyl cellulose. Step S3: Add 13g halloysite and 100mL deionized water to a beaker and mix for 30min to obtain a suspension; add the suspension and 2.5g modified carboxymethyl cellulose to a three-necked flask equipped with a stirrer and thermometer, mix and stir for 1.5h, transfer to a centrifuge, centrifuge at 8300g to degas for 15min, add 1.3g epichlorohydrin, mix and stir at 25℃ for 30min, heat in a water bath at 60℃ for 30min, put into γ-polyglutamic acid fermentation broth, vacuum impregnate at -0.085MPa for 30min, freeze dry at -50℃ for 24h, add 0.4g sodium alginate and 75mL of 2% calcium chloride solution, solidify for 12h, wash 3 times with distilled water, and dry at 45℃ for 3.5h to obtain the soil conditioner; Step S4: Mix 10 parts of soil for planting mangrove seedlings with 0.07 parts of soil conditioner, 1.3 parts of rice straw, and 0.8 parts of shell fragments to obtain mixed soil; apply 0.023 parts of a fungicide with an effective viable bacteria count of 2.0 × 10⁻⁶ to the above mixed soil. 9 CFU / g of Bacillus licheniformis was dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0027] Comparative Example 3: This comparative example illustrates a soil improvement method for planting mangrove seedlings, comprising the following steps: Step S1: Wash 8g of rice straw twice with distilled water, dry at 65℃ for 1.5h, crush and sieve through a 40-mesh sieve, place in a ceramic crucible, and pyrolyze in a box furnace. Set the heating rate to 10℃ / min, heat to 400℃ and then pyrolyze at a constant temperature for 2h. Allow to cool naturally to 25℃, place in a conical flask, add 60mL of 50% phosphoric acid solution, mix and stir for 11h, wash three times with distilled water, and dry at 55℃ for 2.5h to obtain an intermediate product. Add 15g of zero-valent iron nanoparticles and the intermediate product to a beaker, mix and stir for 1.5h, use agate beads as the ball milling medium, with a ball-to-material ratio of 13:1, place in a planetary ball mill, purge with nitrogen protection, and ball mill at 300r / min for 9h to obtain organic matter. Step S2: Mix 10 parts of soil for planting mangrove seedlings with 1.3 parts of organic matter and 0.8 parts of shell fragments to obtain mixed soil; apply 0.023 parts of a fungicide with an effective viable bacteria count of 2.0 × 10⁻⁶ to the above mixed soil. 9 CFU / g of Bacillus licheniformis was dried at 30℃ for 1 hour to obtain improved soil for planting mangrove seedlings.

[0028] Mangrove seedlings were planted in the improved soils of Examples 1-3 and Comparative Examples 1-3 according to GB / T 44592-2024 standard. The survival rate (the percentage of surviving seedlings in the remediation area out of the initial planted seedlings) and retention rate (the percentage of seedlings that remained healthy during the monitoring period after planting in the remediation area out of the initial planted seedlings) were tested according to LY / T 2083-2013 standard. The test results are as follows: Figure 1 As shown: Comparing Examples 1-3 with Comparative Examples 1-3 reveals the following: Examples 1-3 introduced structural modifications, resulting in soil conditioners with long-lasting antibacterial effects, nutrient replenishment, and soil salinity regulation. Example 1 used the lowest dosage of the core conditioner, leading to limited improvement in efficacy. While Example 3 used the highest dosage, excessive chemical cross-linking agents interfered with the initial soil microbial environment, inhibiting initial microbial activity. Example 2 exhibited a balanced distribution across all groups, providing the most stable and sustained multiple advantages. Comparative Example 1 only provided basic physical structure and organic matter replenishment, lacking antibacterial properties. The core functions of soil amendment, such as growth promotion and pollution remediation, are insufficient to cope with the early growth stress of mangrove seedlings. Comparative Example 2 uses soil conditioner plus ordinary rice straw, which has long-lasting antibacterial and growth-promoting capabilities, but its soil structure improvement is limited and it lacks the function of remediating pollutants such as heavy metals, and cannot provide the best habitat for the inoculant. Comparative Example 3 uses organic matter plus ordinary substrate, which can retain pollutants, improve structure and protect microorganisms, but it lacks a durable antibacterial barrier against soil-borne pathogens, and it also lacks biostimulants such as γ-polyglutamic acid to directly promote growth, resulting in a low improvement effect.

[0029] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A soil improvement method for planting mangrove seedlings, characterized in that, Includes the following steps: Soil for planting mangrove seedlings is mixed with soil conditioner, organic matter and functional filler to obtain mixed soil; microbial agents are applied to the above mixed soil and then dried to obtain improved soil for planting mangrove seedlings.

2. The soil improvement method for planting mangrove seedlings according to claim 1, characterized in that, The weight ratio of the soil, soil conditioner, organic matter, functional filler, and microbial agent used for planting mangrove seedlings is 10: 0.05-0.08：1-1.5：0.5-1：0.02-0.025。 3. The soil improvement method for planting mangrove seedlings according to claim 1, characterized in that, The functional filler is one or more of the following: shell fragments, coarse sand, and wood chips.

4. The soil improvement method for planting mangrove seedlings according to claim 1, characterized in that, The microbial agent is a salt- and alkali-tolerant plant rhizosphere growth-promoting agent with an effective viable count of 2.0 × 10⁻⁶ bacteria. 9 CFU / g, the bacterial species are one or more combinations of Bacillus licheniformis, Bacillus megaterium, and gelatinous spore-forming bacteria.

5. A soil improvement method for planting mangrove seedlings according to claim 1, characterized in that, The soil conditioner is prepared by the following steps: Step a1: Mix carboxymethyl cellulose and deionized water, add sodium periodate solution, adjust pH with sulfuric acid solution, mix and stir, precipitate with anhydrous ethanol, wash, and freeze-dry to obtain intermediate product; mix berberine hydrochloride and 2,4-dimethoxybenzylamine, cool, wash, freeze-dry, add methanol and concentrated hydrochloric acid solution, mix and stir, filter, wash filter cake with ethanol solution, freeze-dry to obtain modified carboxymethyl cellulose; Step a2: Add the intermediate product, modified carboxymethyl cellulose and deionized water to a three-necked flask, adjust the pH with a pH adjuster, mix and stir, dialyze, freeze dry to obtain modified carboxymethyl cellulose; Step a3: Mix clay minerals and deionized water to obtain a suspension; add the suspension and modified carboxymethyl cellulose to a three-necked flask, mix and stir, centrifuge to degas, add crosslinking agent, mix and stir to react, heat in a water bath, put into fermentation broth, vacuum impregnate, freeze dry, add sodium alginate and calcium chloride solution, solidify reaction, wash, dry, and obtain soil conditioner.

6. A soil improvement method for planting mangrove seedlings according to claim 5, characterized in that, In step a1, the ratio of carboxymethyl cellulose, deionized water, sodium periodate solution, berberine hydrochloride, 2,4-dimethoxybenzylamine, methanol, and concentrated hydrochloric acid solution is 1-2g: 20-40mL: 10-20mL: 7-8g: 15-20mL: 30-50mL: 10-15mL; the carboxymethyl cellulose is one of carboxymethyl cellulose ammonium, carboxymethyl cellulose sodium, and carboxymethyl cellulose potassium; the concentration of the sodium periodate solution is 0.11g / mL; the concentration of the sulfuric acid solution is 1mol / L; the mass fraction of the concentrated hydrochloric acid is 36-38%; and the mass fraction of the ethanol solution is 80%.

7. A soil improvement method for planting mangrove seedlings according to claim 5, characterized in that, The ratio of the intermediate product, modified carboxymethyl cellulose, and deionized water in step a2 is 0.1-0.2g:0.5-1g:20-40mL; the pH adjuster is 0.1-0.5mol / L acetate-sodium acetate buffer solution.

8. A soil improvement method for planting mangrove seedlings according to claim 5, characterized in that, In step a3, the ratio of clay mineral, deionized water, modified carboxymethyl cellulose, crosslinking agent, sodium alginate, and calcium chloride solution is 10-15g:100mL:2-3g:1-1.5g:0.3-0.5g:50-100mL; the clay mineral is one or more combinations of halloysite, laterite, and kaolin; the crosslinking agent is epichlorohydrin; the mass fraction of the calcium chloride solution is 2%; and the fermentation broth is γ-polyglutamic acid fermentation broth.

9. A soil improvement method for planting mangrove seedlings according to claim 1, characterized in that, The organic matter is prepared by the following steps: Straw was washed, dried, crushed and sieved, then placed in a box furnace for pyrolysis, cooled, and then mixed with phosphoric acid solution. After washing and drying, an intermediate product was obtained. Zero-valent iron nanoparticles and the intermediate product were mixed and stirred, and then ball-milled to obtain organic matter.

10. A soil improvement method for planting mangrove seedlings according to claim 9, characterized in that, The ratio of straw, phosphoric acid solution, and zero-valent iron nanoparticles is 5-10g: 50-70mL: 10-20g; the straw is one of corn straw, soybean straw, and rice straw; the phosphoric acid solution has a mass fraction of 50%.

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