Saline-alkali soil remediation agent and soil remediation method

Abstract

The invention discloses a saline-alkali soil remediation agent and a soil remediation method, and relates to the technical field of soil improvement. The saline-alkali soil remediation agent is prepared from desulfurized gypsum, sodium humate, sodium lignosulphonate, furfural residues, pyroligneous liquor and a polyacrylamide derivative. Specific monomer polymerization is adopted to prepare the polyacrylamide derivative with salt and alkali reducing effects, other formula components are added to prepare the saline-alkali soil remediation agent, and the comprehensive remediation effect of saline-alkali soil is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and in particular to a saline-alkali soil repair agent and a soil repair method. Background Art

[0002] All kinds of saline-alkali soils are formed under certain natural conditions. The essence of their formation is mainly the horizontal and vertical redistribution of various soluble salts on the ground, so that salt gradually accumulates on the soil surface. The main factors affecting the formation of saline-alkali soil are: climate conditions, terrain conditions, the influence of rivers and seawater, etc.

[0003] Specifically, in the arid and semi-arid areas of Northeast my country, Northwest China, and North China, the precipitation is small and the evaporation is large, so the salt dissolved in the water tends to accumulate on the soil surface. In summer, the rainfall is abundant and concentrated, and a large amount of soluble salts infiltrate into the lower layer or flow away with the water. This is the "desalination" season; in spring, the surface water evaporates strongly, and the salt in the groundwater gathers on the soil surface with the rise of capillary water. This is the main "re-salting" season. The saline-alkali soil in Northeast China, North China, and semi-arid areas has an obvious "re-salting" season. The height of the terrain also has a great influence on the formation of saline-alkali soil. The height of the terrain directly affects the movement of surface water and groundwater, which is closely related to the movement and accumulation of salt. From the perspective of the terrain, water-soluble salts move from high to low with water and accumulate in low-lying areas. Saline-alkali soil is mainly distributed in inland basins, mountain depressions, and flat plains with poor drainage, such as the Songliao Plain. From the perspective of small terrain (local scope), the accumulation of salt in soil is the opposite of that in large terrain, and salt tends to accumulate in small convex parts of the soil. The coarseness and fineness of the texture can affect the speed and height of the movement of soil capillary water. Generally speaking, the capillary water of loamy soil rises faster and higher, while sandy soil and clay accumulate salt more slowly. The key issues affecting soil salinity and alkalinity are the height of the groundwater level and the degree of groundwater mineralization. A high groundwater level and high mineralization make it easy for salt to accumulate. In addition, the land on both sides of rivers and channels has its groundwater level raised due to lateral infiltration of river water, which promotes salt accumulation. Coastal saline-alkali soil can be formed in coastal areas due to seawater infiltration.

[0004] At present, there has been some research on using polymers to improve soil. For example, Chinese patent CN117106457A discloses a high-salt and high-alkali soil conditioner and its preparation method and application. The high-salt and high-alkali soil conditioner includes component A solution; component A solution includes the following components in parts by weight: 25-65 parts of shale, 15-30 parts of sepiolite, 10-20 parts of octylphenol polyoxyethylene ether, 80-200 parts of sulfuric acid solution, and the high-salt and high-alkali soil conditioner also includes component B colloid, and component B colloid includes the following components in parts by weight: 16-20 parts of chitosan, 15-20 parts of ferrous chloride, 30-70 parts of hydrochloric acid solution, 8-10 parts of polymethacrylate N,N-dimethylaminoethyl ester, and 1-3 parts of cross-linking agent. Through the above technical solution, the problem that the existing soil conditioner cannot treat high-salt and high-alkali soil is solved.

[0005] PAM (polyacrylamide) and its derivatives have good adhesion and flocculation properties. They can significantly improve the physical properties of the soil when applied to the soil. They have good application prospects when used in soil conditioners. Most of the current soil remediation agent formulas are concentrated on polyacrylamide, and there are fewer studies on the use of polyacrylamide derivatives. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a saline-alkali soil remediation agent and a method for soil remediation, by adopting specific monomer polymerization to prepare a polyacrylamide derivative with salt and alkali reducing effects, and adding other formula ingredients to prepare a saline-alkali soil remediation agent, thereby further improving the comprehensive remediation effect of saline-alkali land.

[0007] To achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0008] On the one hand, the present invention provides a saline-alkali soil remediation agent, comprising: desulfurized gypsum, sodium humate, sodium lignosulfonate, furfural residue, wood vinegar and polyacrylamide derivatives.

[0009] Preferably, the saline-alkali soil remediation agent comprises, by weight: 50-150 parts of desulfurized gypsum, 1-10 parts of sodium humate, 1-10 parts of sodium lignosulfonate, 10-30 parts of furfural residue, 5-25 parts of diatomaceous earth, and 1-20 parts of polyacrylamide derivative.

[0010] Further preferably, the saline-alkali soil remediation agent comprises, by weight: 60-120 parts of desulfurized gypsum, 3-8 parts of sodium humate, 3-8 parts of sodium lignosulfonate, 12-25 parts of furfural residue, 10-20 parts of diatomaceous earth, and 5-10 parts of polyacrylamide derivatives.

[0011] More preferably, the saline-alkali soil remediation agent comprises, by weight: 80 parts of desulfurized gypsum, 5 parts of sodium humate, 6 parts of sodium lignosulfonate, 20 parts of furfural residue, 17 parts of diatomaceous earth, and 8 parts of polyacrylamide derivative.

[0012] Preferably, the preparation method of the polyacrylamide derivative comprises the following steps:

[0013] (1) Mix and dissolve water, sodium sulfate, ammonium sulfate, and PEG to obtain a mixture 1;

[0014] (2) adding acrylamide, disproportionated rosin resin acid vinyl ester, and methacrylic acid to mixture 1 and dissolving them completely to obtain mixture 2;

[0015] (3) Dissolve ammonium persulfate, potassium bromate and sodium bisulfite in water, mix with mixture 2, raise the temperature to 50-70° C. and keep the temperature to react for 5-12 hours, and dry the obtained product to obtain a polyacrylamide derivative.

[0016] Further preferably, in step (1), the amount of sodium sulfate added is 1-3 kg, more preferably 1.5 kg, based on 25 kg of water.

[0017] Further preferably, in step (1), the amount of ammonium sulfate added is 1-3 kg, more preferably 1.5 kg, based on 25 kg of water.

[0018] Further preferably, in step (1), based on 25 kg of water, the amount of PEG added is 0.1-0.5 kg, more preferably 0.3 kg.

[0019] Further preferably, in step (2), based on 25 kg of water, the amount of acrylamide added is 5-10 kg, and further preferably 6 kg.

[0020] Further preferably, in step (2), the amount of disproportionated rosin resin acid vinyl ester added is 0.3-1 kg, more preferably 1 kg, based on 25 kg of water.

[0021] Further preferably, in step (2), the amount of methacrylic acid added is 0.5-3 kg, more preferably 2 kg, based on 25 kg of water.

[0022] Further preferably, in step (2), the mass ratio of acrylamide, 1 kg of disproportionated rosin resin acid vinyl ester, and 2 kg of methacrylic acid is 5-10:1-2:1.5-2.5, and further preferably 6:1:2.

[0023] Further preferably, in step (3), the mass ratio of ammonium persulfate, potassium bromate and sodium bisulfite is 1-2:1-2:1-2, and further preferably 1:1:1.

[0024] More preferably, in step (3), the temperature is raised to 57° C. and the reaction is maintained for 10 hours.

[0025] As a preferred example of the present invention, the method for preparing the anionic polymer comprises the following steps:

[0026] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1.5kg of sodium sulfate, 1.5kg of ammonium sulfate, and 0.3kg of PEG, and stir thoroughly to dissolve them completely;

[0027] (2) Add 6 kg acrylamide, 1 kg disproportionated rosin resin acid vinyl ester, and 2 kg methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0028] (3) Weigh 0.5 g of ammonium persulfate, 0.5 g of potassium bromate, and 0.5 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 57° C. and keep the temperature to react for 10 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0029] More preferably, the molecular weight of the polyacrylamide derivative is 4-6 million, and more preferably 4.5-5 million.

[0030] On the other hand, the present invention provides a method for preparing the above-mentioned saline-alkali land soil remediation agent, comprising the following steps: uniformly mixing reduced amounts of desulfurized gypsum, sodium humate, sodium wood sulfonate, furfural residue, wood vinegar and polyacrylamide derivatives to obtain the obtained product.

[0031] Finally, the present invention provides a method for repairing soil, comprising the step of applying the above-mentioned saline-alkali soil repairing agent to the soil.

[0032] Preferably, the amount applied is 400-600 kg / mu, more preferably 450 kg / mu.

[0033] The beneficial effects of the present invention are:

[0034] The present invention prepares polyacrylamide derivatives by polymerizing acrylamide, disproportionated rosin resin acid vinyl ester, and methacrylic acid. After the reaction, a rosin tricyclic structure is introduced into the polymer side chain, which is staggered with methacrylic acid to form a brush-like object, which is conducive to chelating insoluble calcium salts, preventing salt migration, and wrapping water to prevent water loss, thereby specifically improving the improvement effect on saline-alkali land. The saline-alkali land soil remediation agent is prepared by combining desulfurized gypsum, sodium humate, sodium wood sulfonate, furfural residue, wood vinegar and polyacrylamide derivatives, reducing the amount of polymer used and further improving the comprehensive remediation effect of saline-alkali land. DETAILED DESCRIPTION

[0035] In order to make the technical means, creative features, purpose and efficacy of the present invention easy to understand, the present invention is further explained in conjunction with specific embodiments below, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work all belong to the protection scope of the present invention. In the following embodiments, unless otherwise specified, the operating methods used are conventional operating methods, the equipment used are conventional equipment, and the equipment materials used in each embodiment are the same.

[0036] In the following examples, the molecular weight of commercially available anionic polyacrylamide is 6 million, CAS: 62649-23-4. Sodium humate was purchased from Jinan Hongtu Chemical; sodium lignosulfonate was purchased from Hefeiheng; furfural residue was purchased from Hebei Wangniu Agriculture; and diatomaceous earth was purchased from Hebei Xinxu.

[0037] Example 1 Preparation of polyacrylamide derivatives

[0038] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1.5kg of sodium sulfate, 1.5kg of ammonium sulfate, and 0.3kg of PEG, and stir thoroughly to dissolve them completely;

[0039] (2) Add 6 kg acrylamide, 1 kg disproportionated rosin resin acid vinyl ester, and 2 kg methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0040] (3) Weigh 0.5 g of ammonium persulfate, 0.5 g of potassium bromate, and 0.5 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 57° C. and keep the temperature to react for 10 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0041] Example 2 Preparation of polyacrylamide derivatives

[0042] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 3kg of sodium sulfate, 3kg of ammonium sulfate, and 0.5kg of PEG, and stir thoroughly to dissolve them completely;

[0043] (2) Add 10 kg of acrylamide, 1 kg of disproportionated rosin resin acid vinyl ester, and 2.5 kg of methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0044] (3) Weigh 0.8 g of ammonium persulfate, 0.4 g of potassium bromate, and 0.4 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 50° C. and keep the temperature for 12 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0045] Example 3 Preparation of polyacrylamide derivatives

[0046] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1kg of sodium sulfate, 1kg of ammonium sulfate, and 0.1kg of PEG, and stir thoroughly to dissolve them completely;

[0047] (2) Add 5 kg of acrylamide, 0.3 kg of disproportionated rosin resin acid vinyl ester, and 0.5 kg of methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0048] (3) Weigh 0.3 g of ammonium persulfate, 0.3 g of potassium bromate, and 0.3 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 70° C. and keep the temperature to react for 5 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0049] Comparative Example 1 Preparation of polyacrylamide derivatives

[0050] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1.5kg of sodium sulfate, 1.5kg of ammonium sulfate, and 0.3kg of PEG, and stir thoroughly to dissolve them completely;

[0051] (2) Add 6 kg of acrylamide and 2 kg of methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35°C;

[0052] (3) Weigh 0.5 g of ammonium persulfate, 0.5 g of potassium bromate, and 0.5 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 57° C. and keep the temperature to react for 10 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0053] Comparative Example 2 Preparation of polyacrylamide derivatives

[0054] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1.5kg of sodium sulfate, 1.5kg of ammonium sulfate, and 0.3kg of PEG, and stir thoroughly to dissolve them completely;

[0055] (2) Add 6 kg acrylamide, 1 kg dimethylaminoethyl methacrylate, and 2 kg methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0056] (3) Weigh 0.5 g of ammonium persulfate, 0.5 g of potassium bromate, and 0.5 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 57° C. and keep the temperature to react for 10 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0057] Comparative Example 3 Preparation of polyacrylamide derivatives

[0058] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1.5kg of sodium sulfate, 1.5kg of ammonium sulfate, and 0.3kg of PEG, and stir thoroughly to dissolve them completely;

[0059] (2) Add 6 kg of acrylamide, 1 kg of disproportionated rosin resin acid vinyl ester, and 2 kg of dimethylaminoethyl methacrylate, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0060] (3) Weigh 0.5 g of ammonium persulfate, 0.5 g of potassium bromate, and 0.5 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 57° C. and keep the temperature to react for 10 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0061] Comparative Example 4 Preparation of polyacrylamide derivatives

[0062] (1) In a 50L stainless steel reactor equipped with a stirrer, a thermometer, and a reflux condenser, first add 25kg of purified water, then add 1.5kg of sodium sulfate, 1.5kg of ammonium sulfate, and 0.3kg of PEG, and stir thoroughly to dissolve them completely;

[0063] (2) Add 6 kg acrylamide, 2 kg disproportionated rosin resin acid vinyl ester, and 1 kg methacrylic acid, stir until completely dissolved, introduce nitrogen for 30 minutes, and raise the temperature in the reactor to 35° C.;

[0064] (3) Weigh 0.5 g of ammonium persulfate, 0.5 g of potassium bromate, and 0.5 g of sodium bisulfite, add 50 mL of water to dissolve, slowly add to a reaction kettle, raise the temperature to 57° C. and keep the temperature to react for 10 hours. The obtained product is spray-dried to obtain a polyacrylamide derivative.

[0065] Results

[0066] 1. Polymer index

[0067] Testing method: Molecular weight and monomer residue were determined according to GB / T 17514-2017. The results are as follows:

[0068]

[0069] The results show that the residual monomer content of Comparative Examples 3 and 4 is relatively large.

[0070] 2. Inspection of the effect of saline-alkali land improvement

[0071] The salt and alkali reduction effects of the polyacrylamide derivatives prepared in the examples and comparative examples were determined by pot tests. The experiment used a Vashvili pot, and the soil was from saline-alkali soil in the Ordos area of ​​the Inner Mongolia Autonomous Region, which was sieved through a 2 mm sieve and air-dried for later use. The initial pH value of the soil was 9.56 and the salt content of the soil was 6.53 g / kg.

[0072] 2.1 Polymer type screening

[0073] Commercially available anionic polyacrylamide, polyacrylamide derivatives prepared in Examples 1-3 and Comparative Examples 1-4 were respectively mixed uniformly with the remaining ingredients according to the following formula to prepare a soil remediation agent: 80 parts of desulfurized gypsum, 5 parts of sodium humate, 6 parts of sodium lignosulfonate, 20 parts of furfural residue, 17 parts of diatomaceous earth, and 8 parts of polyacrylamide derivatives.

[0074] Soil remediation agent No. 0: no polymer added (80 parts of desulfurized gypsum, 5 parts of sodium humate, 6 parts of sodium lignosulfonate, 20 parts of furfural residue, 17 parts of diatomaceous earth);

[0075] Soil remediation agent No. 1: the polyacrylamide derivative prepared in Example 1;

[0076] Soil remediation agent No. 2: the polyacrylamide derivative prepared in Example 2;

[0077] Soil remediation agent No. 3: the polyacrylamide derivative prepared in Example 3;

[0078] Soil remediation agent No. 4: the polyacrylamide derivative prepared in Comparative Example 1;

[0079] Soil remediation agent No. 5: polyacrylamide derivative prepared in Comparative Example 2;

[0080] Soil remediation agent No. 6: polyacrylamide derivative prepared in Comparative Example 3;

[0081] Soil remediation agent No. 7: polyacrylamide derivative prepared in Comparative Example 4;

[0082] Soil remediation agent No. 8: commercially available anionic polyacrylamide.

[0083] Each soil remediation agent was fully mixed with the test soil, and potted. Each pot contained 15 kg of test soil and 2 g of soil remediation agent. A blank group was set up without adding soil remediation agent. After potting, water was poured until the soil reached saturated water holding capacity, and sowed (corn, Zhengdan 958), 10 seeds per pot. After sowing, the surface was covered with about 0.5 cm of dry soil, and the humidity was maintained at 70% of the field water holding capacity. The seedlings were fixed at the three-leaf stage, 3 plants per pot, and the aboveground weight and root weight of the corn (drying weighing method), soil pH value and salt content (conductivity method) were measured at the harvest time. The results are as follows:

[0084] Soil remediation agent number Soil pH Salt content (g / kg) Plant height (cm) Single bud fresh weight (g / plant) 0 8.74 5.87 166 235 1 7.95 2.50 222 304 2 7.93 2.82 214 287 3 7.95 2.79 210 283 4 8.37 4.10 195 268 5 8.65 5.41 178 246 6 8.06 4.95 197 275 7 8.20 5.03 191 267 8 8.65 5.53 172 244 Blank Group 9.49 6.57 151 218

[0085] The results of the potted plant test show that after adding the polyacrylamide derivatives prepared in Examples 1-3, compared with the soil remediation agent No. 0 obtained without adding the polymer, the salt and alkali reduction effects are significantly improved, indicating that the polyacrylamide derivatives can be used in saline-alkali land improvement, and its improvement effect is also significantly better than that of commercially available polyacrylamide (soil remediation agent No. 8). Comparative Examples 1 and 2 do not introduce disproportionated rosin resin acid vinyl ester monomers, and their soil remediation abilities are significantly different from those of Examples 1-3. Comparative Example 3 uses disproportionated rosin resin acid vinyl ester monomers and dimethylaminoethyl methacrylate for modification, and it is difficult to form an ideal brush-like object. Compared with Examples 1-3, the chelating ability decreases. Comparative Example 4 is also significantly different from Example 1, indicating that the monomer ratio needs to be controlled within a reasonable range.

[0086] 2.2 Screening of polymer addition amount

[0087] The polymer prepared in Example 1 was selected and mixed according to the following formula.

[0088] Formula A: 80 parts of desulfurized gypsum, 5 parts of sodium humate, 6 parts of sodium wood sulfonate, 20 parts of furfural residue, 17 parts of diatomaceous earth, and 8 parts of polyacrylamide derivative (i.e. soil remediation agent No. 1).

[0089] Formula B: 120 parts of desulfurized gypsum, 8 parts of sodium humate, 8 parts of sodium wood sulfonate, 25 parts of furfural residue, 20 parts of diatomaceous earth, and 5 parts of polyacrylamide derivative.

[0090] Formula C: 60 parts of desulfurized gypsum, 3 parts of sodium humate, 3 parts of sodium lignosulfonate, 12 parts of furfural residue, 10 parts of diatomaceous earth, and 10 parts of polyacrylamide derivative.

[0091] The experimental method is the same as before, and the results are as follows:

[0092] Soil pH Salt content (g / kg) Plant height (cm) Single bud fresh weight (g / plant) Recipe A 7.95 2.50 222 304 Recipe B 7.84 3.06 205 280 Recipe C 7.86 2.47 229 311

[0093] The results show that as the amount of polyacrylamide derivative added decreases, the corresponding improvement effect decreases. When the addition amount is increased to about 10%, the improvement effect is improved to a certain extent. Considering the improvement effect and cost comprehensively, formula A is the most preferred formula.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A saline-alkali soil remediation agent, characterized in that: include: Desulfurized gypsum, sodium humate, sodium lignosulfonate, furfural residue, wood vinegar and polyacrylamide derivatives; The preparation method of the polyacrylamide derivative comprises the following steps: (1) Mix and dissolve water, sodium sulfate, ammonium sulfate, and PEG to obtain a mixture 1; (2) adding acrylamide, disproportionated rosin resin acid vinyl ester, and methacrylic acid to mixture 1 and dissolving them completely to obtain mixture 2; (3) Dissolve ammonium persulfate, potassium bromate and sodium bisulfite in water, mix with mixture 2, raise the temperature to 50-70° C. and keep the temperature to react for 5-12 hours, and dry the obtained product to obtain a polyacrylamide derivative.

2. The saline-alkali soil remediation agent according to claim 1, characterized in that: The composition comprises, by weight: 50-150 parts of desulfurized gypsum, 1-10 parts of sodium humate, 1-10 parts of sodium lignosulfonate, 10-30 parts of furfural residue, 5-25 parts of diatomaceous earth, and 1-20 parts of polyacrylamide derivative; Preferably, the saline-alkali soil remediation agent comprises, by weight: 60-120 parts of desulfurized gypsum, 3-8 parts of sodium humate, 3-8 parts of sodium lignosulfonate, 12-25 parts of furfural residue, 10-20 parts of diatomaceous earth, and 5-10 parts of polyacrylamide derivatives; More preferably, the saline-alkali soil remediation agent comprises, by weight: 80 parts of desulfurized gypsum, 5 parts of sodium humate, 6 parts of sodium lignosulfonate, 20 parts of furfural residue, 17 parts of diatomaceous earth, and 8 parts of polyacrylamide derivative.

3. The saline-alkali soil remediation agent according to claim 1, characterized in that: In step (1), based on 25 kg of water, the amount of sodium sulfate added is 1-3 kg, the amount of ammonium sulfate added is 1-3 kg, and the amount of PEG added is 0.1-0.5 kg.

4. The saline-alkali soil remediation agent according to claim 1, characterized in that: In step (2), based on 25 kg of water, the amount of acrylamide added is 5-10 kg, the amount of disproportionated rosin resin acid vinyl ester added is 0.3-1 kg, and the amount of methacrylic acid added is 0.5-3 kg.

5. The saline-alkali soil remediation agent according to claim 1, characterized in that: In step (2), the mass ratio of acrylamide, disproportionated rosin resin acid vinyl ester and methacrylic acid is 5-10:0.5-1:1.5-2.

5.

6. The saline-alkali soil remediation agent according to claim 1, characterized in that: In step (2), the mass ratio of acrylamide, disproportionated rosin resin acid vinyl ester and methacrylic acid is 6:1:

2.

7. The saline-alkali soil remediation agent according to claim 1, characterized in that: In step (3), the mass ratio of ammonium persulfate, potassium bromate and sodium bisulfite is 1-2:1-2:1-2.

8. The saline-alkali soil remediation agent according to claim 1, characterized in that: In step (3), the temperature is raised to 57° C. and the reaction is maintained for 10 hours.

9. The saline-alkali soil remediation agent according to claim 1, characterized in that: The molecular weight of the polyacrylamide derivative is 4-6 million.

10. Provide a method for soil remediation, characterized in that: The method comprises the step of applying the saline-alkali soil remediation agent according to any one of claims 1 to 9 to the soil.

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