Modified marine silt-based planting soil and method for preparing the same

Abstract

The application relates to the field of planting soil, and discloses a modified marine silt-based planting soil and a preparation method thereof. The modified marine silt-based planting soil is prepared by compounding marine silt and a modifier at a mass ratio of 5:0.4-1. The modifier comprises adsorption additives, modified polyvinyl alcohol fibers, fly ash, potassium fulvate, desulfurization gypsum and organic fertilizer. The adsorption additives are prepared by using straw cellulose and sodium alginate as a network framework, and using expanded vermiculite as an adsorption functional unit, and a metal ion cross-linking method is adopted. The modified polyvinyl alcohol fibers are prepared by the following steps: oxidizing polyvinyl alcohol fibers by potassium persulfate and silver nitrate, reacting with triethylenetetramine and hydrochloric acid to generate ammonium salt polyvinyl alcohol fibers, and then further reacting with calcium-based bentonite acidified by hydrochloric acid. The addition of the adsorption additives and the modified polyvinyl alcohol fibers improves the adsorption performance and the soil aggregate stability of the planting soil.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of planting soil and particularly relates to a modified marine silt-based planting soil and a preparation method thereof. BACKGROUND

[0002] Marine silt is widely distributed in China, almost covering coastal and middle-lower reaches of rivers and areas near lakes. Marine silt is a structural soil mainly composed of extremely fine clay-like substances, which is deposited in a static water or very slow flowing water environment and is accompanied by microbial action. The construction of engineering facilities in coastal areas produces a large amount of discarded marine silt, and the "constantly regenerating" marine silt brings great difficulties and hidden dangers to the construction and maintenance of offshore environments and engineering facilities, and wastes the potential application value of marine silt.

[0003] Due to the characteristics of high salt content, heavy texture, poor structure, low organic matter and available nutrient indicators of marine silt, the salt density inside and outside the plant root system is not the same after the plant absorbs water in silt soil, and the increase of soil solution osmotic pressure easily causes the plant to be in a dehydrated state and physiological drought. In addition, due to the small porosity and permeability coefficient of marine silt, the adsorption performance is poor, which leads to easy water loss of the plant, and the increase of salt in the soil causes the soil structure to be sticky and hard, and the microbial activity is poor, which cannot provide favorable conditions for the growth of plants. SUMMARY

[0004] In order to solve the problems mentioned in the background, the purpose of the present application is to provide a modified marine silt-based planting soil and a preparation method thereof. The adsorbent additive, modified polyvinyl alcohol fiber, fly ash, potassium fulvic acid, desulfurization gypsum and organic fertilizer are used as raw materials to prepare the modifier of marine silt, wherein the addition of the adsorbent additive and the modified polyvinyl alcohol fiber improves the adsorption performance and soil aggregate stability of the planting soil.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A modified marine silt-based planting soil is prepared by compounding marine silt and a modifier at a mass ratio of 5:0.4-1; the modifier comprises the following raw materials in parts by weight: 10-20 parts of adsorbent additive, 5-10 parts of modified polyvinyl alcohol fiber, 1-3 parts of fly ash, 0.5-2 parts of potassium fulvic acid, 0.5-2 parts of desulfurization gypsum and 5-12 parts of organic fertilizer;

[0007] The adsorbent additive is prepared by using straw cellulose and sodium alginate as a network framework, expanding vermiculite as an adsorption functional unit, and adopting a metal ion crosslinking method; the modified polyvinyl alcohol fiber is prepared by oxidizing polyvinyl alcohol fiber with potassium persulfate and silver nitrate, then reacting with triethylenetetramine and hydrochloric acid to generate ammonium salt polyvinyl alcohol fiber, and then further reacting with calcium-based bentonite acidified with hydrochloric acid.

[0008] Preferably, the preparation method of the adsorption additive comprises the following steps:

[0009] (1) The straw is washed, dried and crushed to obtain straw powder, then sodium hydroxide solution is added for mixing, heated at 80-95℃ for 2-3h, cooled and filtered, washed and dried to obtain the filter residue, then nitric acid solution is added, heated at 80-90℃ for 1.5-2h, cooled and filtered, washed and dried to prepare the straw cellulose;

[0010] (2) The sodium hydroxide solution and urea solution are mixed, cooled to -14 to -10℃ to form a mixed solution, the straw cellulose and sodium alginate are dissolved in the mixed solution respectively, then frozen at -14 to -10℃ for 10-12h and naturally thawed at room temperature to obtain straw solution and sodium alginate solution, then the two solutions are mixed, expanded vermiculite is added and stirred fully, ultrasonic degassing is performed, then anhydrous calcium chloride hydrochloride solution is added, solidified for 42-48h, filtered, washed and freeze-dried to prepare the adsorption additive.

[0011] Preferably, the mass concentration of the sodium hydroxide solution is 5-10%, the mass concentration of the urea solution is 10-15%, and the mass concentration of the anhydrous calcium chloride hydrochloride solution is 10-15%.

[0012] Preferably, the mass concentration of the straw cellulose solution and the sodium alginate solution is 2-5%.

[0013] Preferably, the preparation method of the modified polyvinyl alcohol fiber comprises the following steps:

[0014] A. The potassium persulfate is taken and mixed uniformly with silver nitrate aqueous solution, then polyvinyl alcohol fiber is added, stirred and reacted at 60-80℃ for 2-5h, then washed and dried to prepare carboxylated polyvinyl alcohol fiber;

[0015] B. The carboxylated polyvinyl alcohol fiber, N,N'-diisopropyl carbodiimide and 1-hydroxybenzotriazole are taken and uniformly dispersed in N,N-dimethylformamide by ultrasonic, then triethylenetetramine is added, stirred and mixed for 20-24h, then filtered, washed and ultrasonically dispersed in deionized water, then hydrochloric acid is added dropwise under stirring for 20-30min to prepare ammonium saltized polyvinyl alcohol fiber;

[0016] C. The calcium bentonite is taken and added into 1-3mol / L hydrochloric acid solution, reacted at 80-95℃ for 2-4h, cooled to room temperature, then centrifuged, washed and dried to prepare acidified calcium bentonite;

[0017] D, the acidified calcium bentonite is dispersed in deionized water by ultrasonic, and is stirred at 70-85 DEG C for 0-1 h, then the ammonium salt polyvinyl alcohol fiber is added, and constant temperature stirring is continued for 18-24 h, finally the modified polyvinyl alcohol fiber is prepared by filtration, washing and freeze drying.

[0018] Preferably, the mass ratio of the carboxylated polyvinyl alcohol fiber, N, N'-diisopropyl carbodiimide, 1-hydroxybenzotriazole and triethylene tetramine in step B is 1:0.01-0.03:0.01-0.03:0.4-0.7.

[0019] Preferably, the mass ratio of the acidified calcium bentonite and the ammonium salt polyvinyl alcohol fiber in step D is 1:1-2.

[0020] Preferably, the particle size of the calcium bentonite is 40-100 mesh; and the size of the polyvinyl alcohol fiber is 7-10 mm.

[0021] The preparation method of the modified marine silt-based planting soil as described above comprises the following steps:

[0022] S1, a weight part of the adsorption additive, the modified polyvinyl alcohol fiber, the fly ash, the potassium fulvate, the desulfurization gypsum and the organic fertilizer is stirred and mixed uniformly to obtain a modifier;

[0023] S2, the marine silt is pretreated by turning and airing until the soil body is loose, then the modifier is added and stirred and dispersed to prepare the modified marine silt-based planting soil.

[0024] The present application has the following beneficial effects:

[0025] The present application uses the adsorption additive, the modified polyvinyl alcohol fiber, the fly ash, the potassium fulvate, the desulfurization gypsum and the organic fertilizer as raw materials to prepare the modifier of the marine silt, so as to change the pore structure, the soil texture and the organic matter content of the modified marine silt-based planting soil, and meet the relevant requirements of the qualified greening planting soil. The fly ash and the desulfurization gypsum can effectively promote the leaching of sodium ions in the soil, reduce the content of bicarbonate ions, and increase the contents of calcium ions, magnesium ions, sulfate ions and potassium ions. The potassium fulvate is a pure natural active potassium fertilizer, which can effectively provide the nutrient components of plants, maintain the soil porosity and water retention, adjust the pH value, and adsorb certain salt ions, which is beneficial to the growth and development of crops.

[0026] The application utilizes sodium hydroxide solution and nitric acid solution to extract cellulose from straw, and then uses the straw cellulose and sodium alginate as a network framework, the expanded vermiculite as an adsorption functional unit, and a metal ion cross-linking method to prepare a porous microspherical adsorption additive. The straw cellulose has good toughness and porosity, and can improve the soil texture. The sodium alginate is derived from kelp or seaweed, and is a biocompatible and biodegradable anionic natural polysaccharide containing hydroxyl and carboxyl on the molecular chain, which is used as a membrane layer together with the straw cellulose. The porous structure and expansion performance of the expanded vermiculite make it have good adsorption, water absorption and moisture retention, and air permeability, and can adsorb soluble salt to reduce the content of soluble salt in the soil. The expanded vermiculite has high slow-release and ion exchange capacity, and the contained mineral nutrients such as potassium, calcium and magnesium can be released in an appropriate amount for plant absorption and utilization. The expanded vermiculite is loaded on the surface and inside of the adsorption additive, and has a synergistic effect and complementary effect with the straw cellulose and calcium alginate membrane layer, increases the soil pore, increases the adsorption sites of the adsorption additive, and improves the adsorption performance and nutrient absorption of the plant.

[0027] The application utilizes an oxidant potassium persulfate and a catalyst silver nitrate to perform oxidation treatment on polyvinyl alcohol fibers to prepare carboxylated polyvinyl alcohol fibers, which are then reacted with triethylenetetramine and hydrochloric acid under the action of N,N'-diisopropyl carbodiimide and 1-hydroxybenzotriazole to generate ammonium salt polyvinyl alcohol fibers, which are then further reacted with acidified calcium bentonite. The acidified calcium bentonite has the advantages of large specific surface area, excellent adsorption performance, water absorption and expansion, etc. The ammonium salt cations on the surface of the polyvinyl alcohol fibers are subjected to cation exchange with calcium ions and magnesium ions in the acidified calcium bentonite, so that the cations enter the crystal structure of the acidified calcium bentonite, and then the acidified calcium bentonite and the polyvinyl alcohol fibers are combined in the form of ionic bonds. The existence of the nanoparticles increases the roughness of the surface of the polyvinyl alcohol fibers, improves the bonding capacity of the polyvinyl alcohol fibers, and is more conducive to the bonding of the polyvinyl alcohol fibers with the soil particles to form large aggregates, thereby improving the soil structure. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0029] A preparation method of the adsorption additive in the embodiment 1 comprises the following steps:

[0030] (1) 100 g of corn straw was washed, dried and crushed to obtain straw powder, then mixed with 2.5 mol / L sodium hydroxide solution, heated at 90°C for 2 h, cooled and filtered, washed and dried to obtain the filter residue, then added to 4 mol / L nitric acid solution, heated at 80°C for 2 h, cooled and filtered, washed and dried to obtain straw cellulose;

[0031] (2) A mixture of 7% sodium hydroxide solution and 12% urea solution was prepared, and the temperature was lowered to -12°C to form a mixed solution. 10 g of straw cellulose and 10 g of sodium alginate were dissolved in 500 mL of the mixed solution, respectively, and then frozen at -12°C for 12 h and naturally thawed at room temperature to obtain a straw solution and a sodium alginate solution. Then the two solutions were mixed, 5 g of expanded vermiculite was added and stirred thoroughly, and then degassed by ultrasonic. Then, 12% anhydrous calcium chloride hydrochloride solution was added, and the mixture was solidified for 48 h. After filtration, washing and freeze-drying, the adsorption additive was prepared.

[0032] Example 2 A method for preparing a modified polyvinyl alcohol fiber comprises the following steps:

[0033] A. 3.5 g of potassium persulfate was added to 0.002 g / mL of silver nitrate aqueous solution and mixed uniformly, then polyvinyl alcohol fiber was added, and the mixture was stirred and reacted at 75°C for 5 h. After the reaction was completed, the product was washed and dried to obtain carboxylated polyvinyl alcohol fiber.

[0034] B. 5 g of carboxylated polyvinyl alcohol fiber, 0.1 g of N, N'-diisopropyl carbodiimide and 0.1 g of 1-hydroxybenzotriazole were added to 250 mL of N, N-dimethylformamide and ultrasonically dispersed uniformly, then 2.5 g of triethylenetetramine was added, and the mixture was stirred and mixed for 24 h. After filtration and washing, the product was ultrasonically dispersed in 250 mL of deionized water, and 14 mL of hydrochloric acid was added dropwise under stirring for 30 min to obtain ammonium saltized polyvinyl alcohol fiber.

[0035] C. 5 g of calcium-based bentonite was added to 50 mL of 1 mol / L hydrochloric acid solution, and the mixture was reacted at 85°C for 4 h. After cooling to room temperature, the product was centrifuged, washed and dried to obtain acidified calcium-based bentonite.

[0036] D. 5 g of acidified calcium-based bentonite was ultrasonically dispersed in 100 mL of deionized water, and the mixture was stirred at 85°C for 0.5 h. Then 5 g of ammonium saltized polyvinyl alcohol fiber was added, and the mixture was continuously stirred at constant temperature for 24 h. Finally, the product was filtered, washed and freeze-dried to obtain modified polyvinyl alcohol fiber.

[0037] Example 3 A modified marine silt-based planting soil is prepared by compounding marine silt and a modifier at a mass ratio of 5:1; the modifier comprises the following raw materials in parts by weight: 10 parts of the adsorption additive prepared in Example 1, 5 parts of the modified polyvinyl alcohol fiber prepared in Example 2, 1.5 parts of fly ash, 0.5 parts of potassium fulvate, 0.7 parts of desulfurized gypsum, and 8 parts of organic fertilizer composted chicken manure.

[0038] The preparation method of the modified marine silt-based planting soil described above comprises the following steps:

[0039] S1, take parts by weight of adsorption additives, modified polyvinyl alcohol fibers, fly ash, potassium fulvate, desulfurized gypsum, and organic fertilizer, and mix them evenly to obtain a modifier;

[0040] S2, take marine silt and sun-dry it for pretreatment until the soil is loose, then add the modifier and stir to disperse, to prepare a modified marine silt-based planting soil.

[0041] Example 4 A modified marine silt-based planting soil is prepared by compounding marine silt and a modifier at a mass ratio of 5:0.7; the modifier comprises the following raw materials in parts by weight: 15 parts of the adsorption additive prepared in Example 1, 7 parts of the modified polyvinyl alcohol fiber prepared in Example 2, 2 parts of fly ash, 1 part of potassium fulvate, 1.2 parts of desulfurized gypsum, and 10 parts of organic fertilizer composted chicken manure.

[0042] The preparation method of the modified marine silt-based planting soil described above is the same as that of Example 3.

[0043] Example 5 A modified marine silt-based planting soil is prepared by compounding marine silt and a modifier at a mass ratio of 1:0.1; the modifier comprises the following raw materials in parts by weight: 18 parts of the adsorption additive prepared in Example 1, 10 parts of the modified polyvinyl alcohol fiber prepared in Example 2, 3 parts of fly ash, 2 parts of potassium fulvate, 2 parts of desulfurized gypsum, and 11 parts of organic fertilizer composted chicken manure.

[0044] The preparation method of the modified marine silt-based planting soil described above is the same as that of Example 3.

[0045] Comparative Example 1 A modified marine silt-based planting soil is prepared by compounding marine silt and a modifier at a mass ratio of 1:0.1; the modifier comprises the following raw materials in parts by weight: 12 parts of corn straw, 6 parts of expanded vermiculite, 10 parts of the modified polyvinyl alcohol fiber prepared in Example 2, 3 parts of fly ash, 2 parts of potassium fulvate, 2 parts of desulfurized gypsum, and 11 parts of organic fertilizer composted chicken manure.

[0046] The preparation method of the modified marine silt-based planting soil described above is the same as that of Example 3.

[0047] Comparative Example 2 A modified marine silt-based planting soil was prepared by compounding marine silt and a modifier at a mass ratio of 1:0.1; the modifier included the following raw materials in parts by weight: 18 parts of the adsorption additive prepared in Example 1, 10 parts of polyvinyl alcohol fiber, 3 parts of fly ash, 2 parts of potassium fulvate, 2 parts of desulfurized gypsum, and 11 parts of organic fertilizer matured chicken manure.

[0048] The modified marine silt-based planting soil was prepared according to the method of Example 3.

[0049] Performance testing

[0050] (1) The modified marine silt-based planting soil prepared in Examples 3-5 was subjected to heavy metal toxicity leaching testing, the leaching solution was acetic acid solution (pH value was 4.93±0.05), and the leaching liquid was Class I-III water (Surface Water Environmental Quality Standard), and the data results are shown in Table 1; a variable head permeation test was performed at room temperature of 20°C, the permeability coefficients of the modified marine silt-based planting soils prepared in Examples 3-5 and Comparative Examples 1-2 were tested, and the average weight diameter and 0.25 mm particle size aggregate content were tested, the number of soil aggregates can represent the stability of soil aggregate structure to a certain extent, the more the number, the more stable the soil aggregate structure, and the data results are shown in Table 2.

[0051] Table 1 Results of heavy metal toxicity leaching testing of samples

[0052]

[0053] As can be seen from the data in Table 1, the leaching concentrations of heavy metals of the modified marine silt-based planting soils prepared in Examples 3-5 are reduced to different degrees, and the stability of heavy metals is improved.

[0054] Table 2 Results of performance testing of samples

[0055]

[0056] As can be seen from the data in Table 2, the permeability coefficients and total porosities of the modified marine silt-based planting soils prepared in Examples 3-5 are increased compared with those of Comparative Examples 1-2, the average weight diameters and 0.25 mm particle size aggregate contents are improved, and the stability of soil aggregates is enhanced. In Comparative Example 1, the adsorption additive is replaced by a simple mixture of corn straw and expanded vermiculite, and the measured permeability coefficient and total porosity are lower than those of Examples 3-5, indicating that the addition of the adsorption additive can improve the adsorption effect of the planting soil; in Comparative Example 2, the polyvinyl alcohol fiber is not modified, and the measured permeability coefficient, average weight diameter, 0.25 mm particle size aggregate content, and total porosity are lower than those of Examples 3-5, indicating that the modification of the polyvinyl alcohol fiber can improve the binding capacity of the polyvinyl alcohol fiber, and the stability of soil aggregates is improved.

[0057] (2) Selecting the kale seedlings with cold tolerance and short growth cycle as the research object of the plant growth performance, 2 pots of each of the modified marine silt-based planting soil prepared in Examples 3-5 and Comparative Examples 1-2 were planted, and a total of 10 pots were planted, with 1 kale in each pot. In order to ensure sufficient sunlight and stable day and night temperature, the planting was carried out in a transparent flower shed with a size of 2m x 2m, and the data results were obtained after 60 days of planting, as shown in Table 3.

[0058] Table 3 Test results of sample planting

[0059]

[0060] From the data results in Table 3, it can be seen that the modified marine silt-based planting soil prepared in Example 3-5 has better growth of the average plant height, stem and leaf weight, and root length of the plants than Comparative Example 1-2.

[0061] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0062] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A modified marine silt-based planting soil, characterized by, Marine silt and modifier are compounded according to the mass ratio of 5:0.4~1; the modifier comprises the following raw materials by weight: adsorption additive 10~20 parts, modified polyvinyl alcohol fiber 5~10 parts, fly ash 1~3 parts, potassium fulvate 0.5~2 parts, desulfurization gypsum 0.5~2 parts, organic fertilizer 5~12 parts; The adsorption additive is made by using straw cellulose and sodium alginate as a network framework, and expanded vermiculite as an adsorption functional unit, and by using a metal ion cross-linking method; the modified polyvinyl alcohol fiber is made by using potassium persulfate and silver nitrate to oxidize polyvinyl alcohol fiber, and then by using triethylenetetramine and hydrochloric acid to generate ammonium saltized polyvinyl alcohol fiber, and then by further reacting with acidified calcium-based bentonite.

2. The modified marine sludge-based planting soil according to claim 1, characterized in that, The preparation method of the adsorption additive comprises the following steps: (1) straw powder is obtained by washing, drying and crushing straw, then sodium hydroxide solution is added and mixed, heated at 80~95℃ for 2~3h, cooled and filtered, washed and dried to obtain filter residue, then nitric acid solution is added and heated at 80~90℃ for 1.5~2h, cooled and filtered, washed and dried to obtain straw cellulose; (2) sodium hydroxide solution and urea solution are mixed, cooled to-14~-10℃ to form a mixed solution, straw cellulose and sodium alginate are dissolved in the mixed solution respectively, then frozen at-14~-10℃ for 10~12h and naturally thawed at room temperature to obtain straw cellulose solution and sodium alginate solution, then the two solutions are mixed, expanded vermiculite is added and stirred fully, ultrasonic degassing is performed, then anhydrous calcium chloride hydrochloride solution is added, solidified for 42~48h, filtered, washed, and freeze-dried to obtain the adsorption additive.

3. The modified marine sludge-based planting soil according to claim 2, characterized in that, The mass concentration of the sodium hydroxide solution is 5~10%; the mass concentration of the urea solution is 10~15%; the mass concentration of the anhydrous calcium chloride hydrochloride solution is 10~15%.

4. The modified marine sludge-based planting soil according to claim 2, characterized in that, The mass concentration of the straw cellulose solution and the sodium alginate solution is 2~5%.

5. The modified marine sludge-based planting soil according to claim 1, characterized in that, The preparation method of the modified polyvinyl alcohol fiber comprises the following steps: A. potassium persulfate is added into silver nitrate aqueous solution and mixed uniformly, then polyvinyl alcohol fiber is added, stirred and reacted at 60~80℃ for 2~5h, then washed and dried to obtain carboxylated polyvinyl alcohol fiber; B. carboxylated polyvinyl alcohol fiber, N,N'-diisopropyl carbodiimide and 1-hydroxybenzotriazole are added into N,N-dimethylformamide and ultrasonic dispersed uniformly, then triethylenetetramine is added, stirred and mixed for 20~24h, then filtered, washed, ultrasonic dispersed in deionized water, and hydrochloric acid is added dropwise under stirring for 20~30min to obtain ammonium saltized polyvinyl alcohol fiber; C. calcium-based bentonite is added into 1~3mol / L hydrochloric acid solution, reacted at 80~95℃ for 2~4h, cooled to room temperature, centrifuged, washed, and dried to obtain acidified calcium-based bentonite; D, the acidified calcium bentonite is ultrasonically dispersed in deionized water, stirred at 70~85℃ for 0.5~1h, then the ammonium saltized polyvinyl alcohol fiber is added, and constant temperature stirring is continued for 18~24h, finally the modified polyvinyl alcohol fiber is prepared by filtration, washing, and freeze drying.

6. The modified marine sludge-based planting soil according to claim 5, characterized in that, The mass ratio of the carboxylated polyvinyl alcohol fiber, N, N'-diisopropyl carbodiimide, 1-hydroxybenzotriazole and triethylenetetramine in step B is 1:0.01~0.03:0.01~0.03:0.4~0.

7.

7. The modified marine sludge-based planting soil according to claim 5, characterized in that, The mass ratio of the acidified calcium bentonite and the ammonium saltized polyvinyl alcohol fiber in step D is 1:1~2.

8. The modified marine sludge-based planting soil according to claim 5, characterized in that, The particle size of the calcium bentonite is 40~100 mesh; the specification of the polyvinyl alcohol fiber is 7~10mm.

9. A method for producing the modified marine sludge-based planting soil according to any one of claims 1 to 8, characterized by, The method comprises the following steps: S1, a certain amount of adsorption additives, modified polyvinyl alcohol fiber, fly ash, potassium fulvate, desulfurization gypsum and organic fertilizer are stirred and mixed uniformly to obtain a modifier; S2, the marine silt is pretreated by sunning until the soil is loose, then the modifier is added and stirred to disperse, and the modified marine silt-based planting soil is prepared.

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