A high-efficiency seed coating agent for saline-alkali soil wheat planting and a preparation method and application thereof

Abstract

This invention discloses a high-efficiency seed coating agent for wheat cultivation in saline-alkali land and its application, belonging to the field of agricultural biotechnology. The coating agent, by weight, comprises 85-90 parts of a 50% modified humic acid solution, 3-5 parts of a novel biostimulant, 1-2 parts of a film-forming agent, 1-2 parts of a preservative, and the remainder being deionized water. The novel biostimulant is 2-(diethylamino)ethyl-L-phenylalanine ester, and the 50% modified humic acid is humic acid-grafted acrylic acid polymer (molecular weight 2500-3010 Da). This invention uses humic acid-grafted acrylic acid polymer as the core carrier, which possesses both strong water retention capacity and ion exchange function, stabilizing the seed germination water environment and adsorbing sodium ions from the soil. The compounded novel biostimulant specifically activates the expression of wheat stress-resistance genes, promoting root growth and chlorophyll synthesis. The synergistic effect of these two factors alleviates saline-alkali stress from two dimensions: environmental improvement and enhancement of crop resistance.

Description

Technical Field

[0001] This invention relates to the field of agrochemical technology, specifically to a high-efficiency seed coating agent for wheat cultivation in saline-alkali land, its preparation method and application, and particularly to a seed coating agent with modified humic acid as the core carrier and compounded with novel biostimulants, and its preparation and application method, which is suitable for large-scale wheat cultivation in different types of saline-alkali lands such as those along the Yellow River and coastal areas. Background Technology

[0002] my country has a total saline-alkali land area of ​​991 million mu (approximately 66.8 million hectares), of which about 105 million mu (approximately 6.7 million hectares) of arable land is saline-alkali soil. This is mainly distributed along the Yellow River basin, coastal areas, and the northwestern inland region. Salinization has become a key bottleneck restricting the improvement of my country's grain production capacity. The high salinity, high pH value, and soil compaction of saline-alkali land disrupt the osmotic pressure balance of wheat seeds, leading to impaired water absorption and difficulty in decomposing endosperm nutrients. Simultaneously, it inhibits the activity of stress-resistance enzymes such as peroxidase and superoxide dismutase, resulting in poor root development, yellowing seedlings, and ultimately a germination rate of only about 50%, with yields reduced by 30%-50% compared to non-saline-alkali land.

[0003] Seed coating technology, as a key means to increase crop yield in saline-alkali land, has been widely used. However, existing products have significant drawbacks. For example, the seed coating agent for saline-alkali land disclosed in patent CN108782963A is mainly a water-retaining agent, which can only improve the water situation and cannot reduce the sodium ion concentration in the soil. In soils with a salt content of more than 0.4%, the germination rate is increased by less than 20%. The nutrient-type coating agent disclosed in patent CN110235691B has nitrogen, phosphorus, and potassium nutrients that are easy to combine with calcium and magnesium ions to form precipitates in a high pH environment. The absorption and utilization rate is less than 30%, which is difficult to alleviate the inhibition of seedlings by saline-alkali stress. Although humic acid coating agents (such as CN111543152A) can slightly improve the soil, they do not contain targeted stress-resistant components. When applied in coastal saline-alkali land (with high chloride ion content), the improvement of wheat stress resistance is not significant, and the yield increase is only 15%-20%.

[0004] Humic acid-grafted acrylic polymers possess a three-dimensional network structure, resulting in a water retention capacity 2-3 times that of traditional water-retaining agents. Furthermore, their ion exchange capacity reaches 5-8 mmol / g, enabling rapid adsorption of sodium and chloride ions in the soil. However, in saline-alkali lands along the Yellow River (high in calcium and magnesium ions) and coastal saline-alkali lands (high in chloride ions), their effectiveness in salt regulation is easily diminished due to ion competition when used alone, and they fail to activate the wheat's own stress resistance mechanisms. Currently, there are no reports of combining humic acid-grafted acrylic polymers with biostimulants that specifically alleviate wheat salt-alkali stress. Therefore, developing a seed coating agent that combines environmental improvement and stress resistance / growth promotion functions, adaptable to different types of saline-alkali lands, is of great significance for solving the challenges of wheat cultivation in saline-alkali areas. Summary of the Invention

[0005] To address the problems of low seed germination rate and low yield in existing wheat cultivation on saline-alkali land, and the limited functionality, poor compatibility, and unsatisfactory synergistic effects of existing seed coating agents, this invention provides a high-efficiency seed coating agent for wheat cultivation on saline-alkali land, its preparation method, and its application. By utilizing the salt-alkali regulation and water retention functions of modified humic acid, combined with the stress-resistance and growth-promoting effects of novel biostimulants, a dual-effect synergistic effect of "environmental improvement + crop stress resistance" is achieved, significantly improving the germination rate and yield of wheat on different types of saline-alkali land. Moreover, the preparation is simple, low-cost, and environmentally friendly.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows: A high-efficiency seed coating agent for wheat cultivation in saline-alkali land comprises the following components by weight: 80-90 parts of 50% modified humic acid solution, 1-5 parts of a novel biostimulant, 0.5-2 parts of a film-forming agent, 1-3 parts of a preservative, and 3-14 parts of deionized water; wherein the novel biostimulant is 2-(diethylamino)ethyl-L-phenylalanine ester; and the modified humic acid is a humic acid-grafted acrylic acid polymer with a molecular weight of 2500-3010 Da. The 50% represents the mass fraction of solids content.

[0007] Preferably, a high-efficiency seed coating agent for wheat planting in saline-alkali land comprises the following components by weight: 85-90 parts of 50% modified humic acid solution, 3-5 parts of novel biostimulant, 1-2 parts of film-forming agent, 1-2 parts of preservative, and 3-14 parts of deionized water.

[0008] The modified humic acid is prepared as follows: In an enamel-lined reactor, potassium humate, potassium hydroxide-neutralized acrylic acid, potassium persulfate, cerium ammonium nitrate, and water are added. The mixture is heated to 80°C with stirring, and simultaneously, a solution of potassium hydroxide-neutralized acrylic acid and potassium persulfate is added dropwise over 1-1.2 hours. This temperature is maintained for 1 hour, and the mixture is cooled before being discharged to obtain a humic acid-grafted acrylic acid polymer with a solid content of 50%. This polymer forms a graft copolymer between the aromatic ring structure of potassium humate and the carboxyl groups of acrylic acid. Its three-dimensional network structure can lock in 300-500 times its own weight in water. Simultaneously, the carboxyl and hydroxyl groups can adsorb sodium ions in the soil through ion exchange, reducing soil salinity.

[0009] The mass ratio of potassium humate, acrylic acid neutralized by the first addition of potassium hydroxide, potassium persulfate, and cerium ammonium nitrate is (75-85):(65-75):(0.4-0.6):1. The acrylic acid neutralized by the first addition of potassium hydroxide is prepared by mixing 20 parts of acrylic acid and 52 parts of 30% potassium hydroxide solution. The mass concentration of the potassium persulfate solution is 10%. The mass ratio of acrylic acid to potassium persulfate solution neutralized by the second addition of potassium hydroxide is (280-320):1. The acrylic acid neutralized by the second addition of potassium hydroxide is prepared by mixing 98 parts of acrylic acid and 200 parts of 30% potassium hydroxide solution. The acrylic acid is prepared by mixing potassium hydroxide solution; the mass ratio of acrylic acid neutralized by potassium hydroxide added in the first addition to that neutralized by potassium hydroxide added in the second addition is (65-75):(280-320); preferably, the mass ratio of potassium humate, acrylic acid neutralized by potassium hydroxide added in the first addition, potassium persulfate, and cerium ammonium nitrate is 80:70:0.5:1, the mass ratio of acrylic acid neutralized by potassium hydroxide added in the second addition to potassium persulfate solution is 300:1, and the mass ratio of acrylic acid neutralized by potassium hydroxide added in the first addition to that neutralized by potassium hydroxide added in the second addition is 70:300.

[0010] The preparation method of the novel biostimulant is as follows: N,N-diethylethanolamine and L-phenylalanine are mixed and dissolved in toluene at a molar ratio of 1:1, and titanium oxysulfate catalyst is added. The reaction is heated under normal pressure, and water is continuously separated by reflux using a water separator. After the reaction is completed, the heating is turned off, and the reaction system is allowed to cool to room temperature. The organic phase is filtered to remove insoluble matter, and the solvent is removed by vacuum distillation under a vacuum of 0.08-0.1 MPa and a temperature of 60-70℃. The crude product is purified by silica gel column chromatography (eluent is n-hexane / ethyl acetate = 1:1, elution flow rate is 2-3 mL / min, and the fraction corresponding to the main peak at a wavelength of 254 nm is collected) to obtain the target product 2-(diethylamino)ethyl-L-phenylalanine ester. This biostimulant can activate the expression of stress-resistance genes (such as TaSOD and TaPOD) by adjusting the ratio of abscisic acid and gibberellin in wheat, thereby increasing the activity of stress-resistance enzymes and promoting root elongation and chlorophyll synthesis.

[0011] The molar ratio of N,N-diethylethanolamine to titanium oxysulfate is 1:(0.04-0.06); the heating reaction temperature is 110-130℃, and the reaction time is 4-8h.

[0012] The film-forming agent is a compound of polyvinyl alcohol and gum arabic in a mass ratio of 1:1. The degree of polymerization of polyvinyl alcohol is 1700-1800 and the degree of alcoholysis is 88%. The 1:1 mass ratio compound has better film-forming properties and good film permeability. The preservative is potassium sorbate.

[0013] The preparation method of the high-efficiency seed coating agent for wheat planting in saline-alkali land includes the following steps: (1) Add deionized water to the reaction vessel, heat to 45-50℃, add film-forming agent, and stir for 30-40 minutes until completely dissolved; (2) Add humic acid-grafted acrylic polymer and preservative in sequence, and stir at a high speed of 800-1000 r / min for 15-20 min to form a uniform aqueous solution; (3) Cool down to 25-30℃, add a new type of biostimulant, stir at 300-500r / min for 20-30min, filter through a 200-mesh filter cloth to remove impurities, and obtain the seed coating agent.

[0014] The application of the high-efficiency seed coating agent for wheat planting in saline-alkali land includes the following steps: adjusting parameters according to the salinity of the soil. When the soil salinity is 0.3%-0.4%, wheat seeds and seed coating agent are mixed at a mass ratio of 100:3 and stirred in a drum coating machine at a speed of 50-60 r / min for 8-10 minutes; when the soil salinity is 0.4%-0.5%, they are mixed at a mass ratio of 100:5 and stirred at a speed of 70-80 r / min for 5-8 minutes. The coating agent is then evenly applied to the seed surface. The seeds are then dried at 20-25℃ and 50%-60% relative humidity until a complete film with a thickness of 0.1-0.2 mm is formed on the seed surface, at which point the seed can be used for sowing in saline-alkali land.

[0015] The saline-alkali land includes saline-alkali land along the Yellow River and coastal saline-alkali land, with a soil pH of 7.5-8.5 and a salt content of 0.3%-0.5%. The application improves wheat emergence rate and yield through the synergistic effect of humic acid grafted acrylic polymer and 2-(diethylamino)ethyl-L-phenylalanine ester.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Significant synergistic effects: Modified humic acid grafted with acrylic polymers stabilizes the moisture environment for seed germination through water retention, while simultaneously adsorbing sodium ions from the soil to reduce salinity; the novel biostimulant specifically activates the expression of wheat stress-resistance genes, increases the activity of stress-resistance enzymes, and promotes root growth and chlorophyll synthesis. The two work synergistically from two dimensions: environmental improvement and enhancement of crop stress resistance. Compared to using modified humic acid or the biostimulant alone, the emergence rate is increased by more than 30%, and the yield is increased by more than 40%.

[0017] 2. Comprehensive functions and strong adaptability: It integrates water retention, salinity regulation, stress resistance and growth promotion, corrosion prevention and film formation, solving the problem of single function of existing coating agents; by adjusting the application parameters, it can be adapted to different types of saline-alkali land such as the Yellow River and coastal areas, as well as different salt content gradients of 0.3%-0.5%, with a wide range of applications.

[0018] 3. Environmentally friendly and highly safe: All components used are modified natural products or biocompatible substances. Modified humic acid can be degraded into organic nutrients, and biostimulants have a short half-life in the soil, leaving no residue. They do not pollute the human body, beneficial organisms, or the environment, and meet the needs of green agricultural development.

[0019] 4. Simple preparation and application: The preparation process does not require special equipment, the raw materials are widely available, and the production cost is reduced by 20%-30% compared with existing similar products; the application method is simple and can be adapted to existing roller coating machines, which is convenient for large-scale promotion. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. 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.

[0021] Example 1: Preparation of Modified Humic Acid In an enamel-lined reactor, 80 kg of potassium humate, 20 kg of acrylic acid neutralized with potassium hydroxide (52 kg of 30% potassium hydroxide), 0.5 kg of potassium persulfate, 1 kg of cerium ammonium nitrate, and 67 kg of water were added. The mixture was heated to 80°C with stirring. Simultaneously, 98 kg of acrylic acid neutralized with potassium hydroxide (200 kg of 30% potassium hydroxide) and 1 kg of potassium persulfate (10% aqueous solution) were added dropwise over 1-1.2 hours. The temperature was maintained for 1 hour, and the mixture was cooled before being discharged to obtain modified humic acid (humic acid grafted with acrylic acid polymer). The molecular weight was measured to be 2500-3010 Da, the solid content was 50%, the water retention ratio was 420 times, and the ion exchange capacity was 6.8 mmol / g.

[0022] Example 2: Preparation of a novel biostimulant L-phenylalanine (0.4 mol), N,N-diethylethanolamine (0.4 mol), toluene (100 mL), and titanium oxysulfate catalyst (0.02 mol) were added to a 250 mL two-necked flask. The mixture was heated to 120 °C under normal pressure, and water was continuously separated by reflux using a water separator. The reaction was continued for 6 h. After the reaction was completed, the heating was turned off, and the system was allowed to cool to room temperature. The organic phase was filtered to remove insoluble matter, and the solvent was removed by vacuum distillation under a vacuum of 0.08-0.1 MPa and a temperature of 60-70 °C. The crude product was purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 1:1, elution flow rate: 2-3 mL / min, collecting the fraction corresponding to the main peak at 254 nm) to obtain the target product 2-(diethylamino)ethyl-L-phenylalanine ester, with a yield of 95% and a purity of 98.5%.

[0023] Structural characterization data: ¹H NMR (400 MHz, D₂O) δ 7.32–7.19 (m, 3H), 7.18–7.05 (m, 2H), 4.50–4.38 (m, 1H), 4.32–4.20 (m, 2H), 3.38–3.05 (m, 4H), 3.02–2.87 (m, 4H), 1.11 (t, J = 4.2 Hz, 6H). ¹³C NMR (400 MHz, D₂O) 166.8, 133.6, 129.2, 129.0, 128.1, 60.2, 53.8, 49.5, 47.7, 35.8, 8.0. HRMS (ESI): [M+H] + calcd for265.1838, found 265.1840.

[0024] Example 3

[0025] This embodiment provides a method for preparing a high-efficiency seed coating agent for wheat cultivation in saline-alkali land, comprising the following steps: (1) Weigh 14 kg of deionized water and add it to the reactor. Heat the reactor to 45°C and add 2 kg of polyvinyl alcohol (polymerization degree 1700-1800, alcoholysis degree 88%). Stir for 35 min until completely dissolved. (2) Weigh 80 kg of 50% modified humic acid and 1 kg of potassium sorbate preservative and add them to the reaction vessel in sequence. Stir at a high speed of 900 r / min for 18 min until the mixture is uniform. (3) Cool down to 25-30℃, add 1Kg of the novel biostimulant 2-(diethylamino)ethyl-L-phenylalanine ester, stir at 400r / min for 25min, filter through 200 mesh filter cloth to remove impurities, and obtain seed coating agent X1.

[0026] Example 4

[0027] This embodiment provides a method for preparing a high-efficiency seed coating agent for wheat cultivation in saline-alkali land, comprising the following steps: (1) Weigh 8.5 kg of deionized water and add it to the reaction vessel. Heat the mixture to 45-50°C, add 0.5 kg of gum arabic, and stir for 30 min until completely dissolved. (2) Weigh 85 kg of 50% modified humic acid and 2 kg of potassium sorbate preservative and add them to the reaction vessel in sequence. Stir at a high speed of 800 r / min for 20 min until the mixture is uniform. (3) Cool down to 25-30℃, add 3Kg of the novel biostimulant 2-(diethylamino)ethyl-L-phenylalanine ester, stir at 300r / min for 30min, filter through 200 mesh filter cloth to remove impurities, and obtain seed coating agent X2.

[0028] Example 5

[0029] This embodiment provides a method for preparing a high-efficiency seed coating agent for wheat cultivation in saline-alkali land, comprising the following steps: (1) Weigh 3 kg of deionized water and add it to the reaction vessel. Heat the mixture to 50°C and add 1 kg of polyvinyl alcohol and gum arabic compound (mass ratio 1:1). Stir for 30-40 min until completely dissolved. (2) Weigh 90 kg of 50% modified humic acid and 3 kg of potassium sorbate preservative and add them to the reaction vessel in sequence. Stir at a high speed of 1000 r / min for 15 min until the mixture is uniform. (3) Cool down to 25-30℃, add 5Kg of the novel biostimulant 2-(diethylamino)ethyl-L-phenylalanine ester, stir at 500r / min for 20min, filter through 200 mesh filter cloth to remove impurities, and obtain seed coating agent X3.

[0030] Application effect test

[0031] Application method: Adjust the parameters according to the salinity of the saline-alkali soil. When the soil salinity is 0.3%-0.4%, mix wheat seeds and seed coating agent at a mass ratio of 100:3 and stir at a speed of 50-60 r / min for 8-10 min in a drum coating machine. When the soil salinity is 0.4%-0.5%, mix at a mass ratio of 100:5 and stir at a speed of 70-80 r / min for 5-8 min. Ensure that the coating agent is evenly attached to the seed surface. Then, dry the seeds at 20-25℃ and 50%-60% relative humidity until a complete film with a thickness of 0.1-0.2 mm is formed on the seed surface. The seeds are then ready for sowing in saline-alkali soil.

[0032] Experimental sites: Three different types of saline-alkali land were selected as experimental fields: Experimental field 1: Saline-alkali land along the Yellow River in Zhaodi Town, Changyuan County, Henan Province (soil pH value 7.9-8.2, salt content 0.3%-0.4%). Experimental field 2: Coastal saline-alkali land in Dongying City, Shandong Province (soil pH value 8.1-8.5, salt content 0.4%-0.5%). Experimental field 3: Inland saline-alkali land in Yuncheng City, Shanxi Province (soil pH value 7.5-7.8, salt content 0.35%-0.45%).

[0033] The experimental crops were all local main wheat varieties (Jimai 44).

[0034] Experimental design: Nine treatment groups were set up in each experimental field, namely, Example 1-3 groups (using the seed coating agents X1-X3 prepared in this invention, and coating at a seed to coating agent mass ratio of 100:3), Example 4-6 groups (using the seed coating agents X1-X3 prepared in this invention, and coating at a seed to coating agent mass ratio of 100:5), and control groups 1-3.

[0035] Control group 1: Uncoated seeds; Control group 2: The coating agent component does not contain the novel biostimulant, and the remaining components and proportions are the same as in Example 3, and the coating method is the same; Control group 3: The coating agent component does not contain 50% humic acid grafted acrylic polymer, and the remaining components and proportions are the same as in Example 3, and the coating method is the same.

[0036] Each treatment group covered an area of ​​1 mu (approximately 0.16 acres), with 3 replicates, randomized block design, and consistent field management practices.

[0037] Measurement indicators: Seedling emergence rate was recorded 20 days after sowing; root length, plant height, and chlorophyll content were measured during the wheat jointing stage; peroxidase (POD) and superoxide dismutase (SOD) activities were measured during the grain-filling stage; and yield was recorded after harvest.

[0038] Experimental results: (1) Seedling emergence rate and yield results (average of 3 experimental fields):

[0039] (2) Key agronomic traits and stress-resistant enzyme activity (comparison between Example 6 group and control group 1, average value of 3 experimental fields):

[0040] The experimental results show that the seed coating agent of the present invention can significantly improve the emergence rate and yield of wheat in different types of saline-alkali land, and can improve the agronomic traits of wheat and increase the activity of stress-resistant enzymes. This confirms the synergistic effect of modified humic acid and novel biostimulants, and fully achieves the expected effect. Among them, Example 6 has the best effect.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-efficiency seed coating agent for wheat cultivation in saline-alkali land, characterized in that, The product comprises the following components by weight: 80-90 parts of 50% modified humic acid solution, 1-5 parts (preferably 3-5 parts) of novel biostimulant, 0.5-2 parts of film-forming agent, 1-3 parts of preservative, and 3-14 parts of deionized water; the novel biostimulant is 2-(diethylamino)ethyl-L-phenylalanine ester; the modified humic acid is a humic acid-grafted acrylic acid polymer with a molecular weight of 2500-3010 Da.

2. The high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 1, characterized in that, The product comprises the following components by weight: 85-90 parts of 50% modified humic acid solution, 3-5 parts of novel biostimulant, 1-2 parts of film-forming agent, 1-2 parts of preservative, and 3-14 parts of deionized water.

3. The high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 1, characterized in that, The modified humic acid is prepared as follows: In an enamel-lined reactor, potassium humate, acrylic acid neutralized with potassium hydroxide, potassium persulfate, cerium ammonium nitrate, and water are added. The mixture is heated to 80°C with stirring, and then acrylic acid and potassium persulfate solutions neutralized with potassium hydroxide are added dropwise over 1-1.2 hours. The temperature is maintained for 1 hour, and the mixture is cooled before being discharged to obtain a humic acid-grafted acrylic acid polymer with a solid content of 50%.

4. The high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 3, characterized in that, The mass ratio of potassium humate, acrylic acid neutralized by the first addition of potassium hydroxide, potassium persulfate, and cerium ammonium nitrate is (75-85):(65-75):(0.4-0.6):

1. The acrylic acid neutralized by the first addition of potassium hydroxide is prepared by mixing 20 parts of acrylic acid and 52 parts of 30% potassium hydroxide solution. The mass concentration of the potassium persulfate solution is 10%. The mass ratio of acrylic acid neutralized by the second addition of potassium hydroxide to potassium persulfate solution is (280-320):

1. The acrylic acid neutralized by the second addition of potassium hydroxide is prepared by mixing 98 parts of acrylic acid and 200 parts of 30% potassium hydroxide solution. The mass ratio of acrylic acid neutralized by the first addition of potassium hydroxide to acrylic acid neutralized by the second addition of potassium hydroxide is (65-75):(280-320).

5. The high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 1, characterized in that, The preparation method of the novel biostimulant is as follows: N,N-diethylethanolamine and L-phenylalanine are mixed and dissolved in toluene at a molar ratio of 1:1, titanium oxysulfate catalyst is added, and the reaction is carried out under normal pressure with continuous reflux to separate water. After the reaction is completed, the heating is turned off, and the reaction system is cooled to room temperature. The organic phase is filtered to remove insoluble matter, and the solvent is removed by vacuum distillation under vacuum conditions of 0.08-0.1 MPa and 60-70℃. The crude product is purified by silica gel column chromatography to obtain the target product 2-(diethylamino)ethyl-L-phenylalanine ester.

6. The high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 5, characterized in that, The molar ratio of N,N-diethylethanolamine to titanium oxysulfate is 1:(0.04-0.06); the heating reaction temperature is 110-130℃, and the reaction time is 4-8h.

7. The high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 1, characterized in that, The film-forming agent is a compound of polyvinyl alcohol and gum arabic in a mass ratio of 1:1, wherein the degree of polymerization of polyvinyl alcohol is 1700-1800 and the degree of alcoholysis is 88%; the preservative is potassium sorbate.

8. The method for preparing the high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Add deionized water to the reaction vessel, heat to 45-50℃, add film-forming agent, and stir for 30-40 minutes until completely dissolved; (2) Add humic acid-grafted acrylic polymer and preservative in sequence, and stir at a high speed of 800-1000 r / min for 15-20 min to form a uniform aqueous solution; (3) Cool down to 25-30℃, add a new type of biostimulant, stir at 300-500r / min for 20-30min, filter through a 200-mesh filter cloth to remove impurities, and obtain the seed coating agent.

9. The application of the high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to any one of claims 1-7, characterized in that, Includes the following steps: Adjust the parameters according to the salinity of the saline-alkali soil. When the soil salinity is 0.3%-0.4%, mix wheat seeds and seed coating agent at a mass ratio of 100:3 and stir at a speed of 50-60 r / min for 8-10 minutes in a drum coating machine. When the soil salinity is 0.4%-0.5%, mix at a mass ratio of 100:5 and stir at a speed of 70-80 r / min for 5-8 minutes. Ensure that the coating agent is evenly attached to the seed surface. Then, dry the seeds at 20-25℃ and 50%-60% relative humidity until a complete film with a thickness of 0.1-0.2 mm is formed on the seed surface. The seeds are then ready for sowing in saline-alkali soil.

10. The application of the high-efficiency seed coating agent for wheat cultivation in saline-alkali land according to claim 9, characterized in that, The saline-alkali land includes saline-alkali land along the Yellow River and coastal saline-alkali land, with a soil pH of 7.5-8.5 and a salt content of 0.3%-0.5%.

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