High-stability nutrient solution containing nano silicon-potassium complex as well as preparation method and application of high-stability nutrient solution

Abstract

The invention provides a high-stability nutrient solution containing a nano silicon-potassium complex as well as a preparation method and application of the high-stability nutrient solution. The nutrient solution comprises the nano silicon-potassium complex, a polymer compatilizer, medium trace elements and a plant-source synergist. The nano silicon-potassium complex is obtained by intercalating and stripping layered silicate and treating the layered silicate with a specific surface modifier, has a lamellar structure with a high specific surface area, and can effectively adsorb nutrient ions and inhibit generation of precipitates; the preparation method comprises the following steps: respectively preparing a compatilizer dispersion liquid and a medium trace element mother solution, dispersing the nano-composite, and mixing the nano-composite with the compatilizer dispersion liquid and the medium trace element mother solution. The high stability of a nutrient solution system is realized through the physical barrier of the nano complex, the chemical synergy of the surface modifier and the stabilizing effect of the polymer compatilizer, no precipitate is generated after the nutrient solution is sealed and stored at room temperature for over 180 days, and meanwhile, the nutrient solution has multiple functions of supplying nutrients, inducing disease resistance and reducing heavy metal absorption of crops, and is suitable for green agricultural production.

Description

Technical Field

[0001] This invention relates to the fields of agricultural chemistry and plant nutrition technology, and in particular to a highly stable nutrient solution containing nano-silicon-potassium composite, its preparation method, and its application. Background Technology

[0002] Water-soluble liquid fertilizers, as key production materials in modern intensive agriculture, are highly favored due to their balanced nutrients, good water solubility, and ease of precise application through irrigation systems. However, traditional complete nutrient liquid fertilizers have long faced a technical bottleneck in research, production, and storage: high concentrations of cations such as calcium, magnesium, and iron readily combine with anions such as phosphate and sulfate under specific pH, concentration, and temperature conditions to form insoluble precipitates, such as calcium phosphate, calcium sulfate, and ferric hydroxide. The formation of these precipitates not only directly reduces the content of available nutrients in the nutrient solution, resulting in decreased fertilizer utilization and economic losses, but also clogs the nozzles and pipes of drip irrigation systems, affecting the uniformity and continuity of fertilization, and even causing system damage, severely restricting the application effect and promotion of liquid fertilizers.

[0003] Conventional techniques for addressing precipitation problems mainly include the use of organic chelating agents and strict pH control. While these methods can alleviate the problem to some extent, they have significant limitations: chelating agents are expensive and their inhibitory effect on different types of precipitation is selective, especially their ability to inhibit precipitation such as calcium phosphate is limited; furthermore, the pH adjustment range is strictly constrained by the optimal range for plant growth, making a fundamental breakthrough difficult. Therefore, developing a novel stable system that can inhibit ion precipitation from a physicochemical perspective has become a key technical challenge that urgently needs to be solved in this field.

[0004] On the other hand, silicon, as a beneficial element, is increasingly valued for its role in enhancing the mechanical strength of plant cell walls and improving resistance to biotic and abiotic stresses. However, conventional water-soluble silicon fertilizers, due to their strong alkalinity, significantly raise the pH of nutrient solutions when added, exacerbating the risk of ion precipitation and severely limiting their application in high-standard, all-element nutrient solutions. How to safely and efficiently introduce silicon nutrients without compromising system stability and synergistically exert its stress-resistance function remains a key technical challenge. Summary of the Invention

[0005] In view of this, the present invention proposes a highly stable nutrient solution containing nano-silicon-potassium composite, its preparation method and application, to solve the above problems.

[0006] The technical solution of the present invention is implemented as follows: a highly stable nutrient solution containing nano-silicon-potassium composite, comprising the following components by mass percentage: 0.5-5% nano-silicon-potassium composite, 0.1-2% polymer compatibilizer, 0.3-3% trace elements, 0.05-0.2% plant-derived synergist, and other auxiliary agents acceptable for nutrient fertilizers.

[0007] Preferably, the particle size of the nano-silicon-potassium composite is 10-50 nm, and the interlayer spacing is 0.5-2 nm.

[0008] Preferably, the nano-silicon-potassium composite is obtained by intercalation, exfoliation, and surface modification of layered silicate minerals, with a particle size of 10-50 nm, an interlayer spacing of 0.5-2 nm, and a specific surface area of ​​100-500 m². 2 / g, wherein the surface modifier is a compound of citric acid and polyaspartic acid in a mass ratio of 1:(1.2-2.5).

[0009] Preferably, the preparation method of the nano-silicon-potassium composite includes the following steps: (a) Intercalation pre-support: The layered silicate minerals are mixed with an aqueous solution of the intercalating agent and stirred at 60-120°C for 2-12 hours. Then, the mixture is separated, washed and dried to obtain the intercalated product. (b) Exfoliation and dispersion: The intercalated product is dispersed in water and exfoliated under high-speed shear. After centrifugation, the supernatant is the nanosheet dispersion. (c) Surface modification and composite: Potassium source compound and surface modifier are added to the nanosheet dispersion, and ion exchange and surface reaction are carried out at 40-80℃ for 1-6 hours. Finally, the nano-silicon potassium composite is obtained by drying.

[0010] More preferably, the layered silicate mineral in step (a) is selected from montmorillonite, vermiculite, or palygorskite, and is pulverized through a 150-250 mesh sieve; the concentration of the intercalating agent aqueous solution is 0.5-3.0 mol / L, and the intercalating agent is selected from at least one of urea, potassium acetate, alkyl ammonium salt, or polyethylene oxide; the mass ratio of the intercalating agent aqueous solution to the silicate mineral is 0.2-1:1; In step (b), the intercalation product is dispersed in deionized water at a concentration of 1-5 wt% and then exfoliated by high-speed shearing at 8000-15000 rpm for 0.5-2 hours. The potassium source in step (c) is selected from potassium hydroxide, potassium carbonate or potassium silicate, and the amount added is 10-30% of the mass of the composite; the amount of surface modifier added is 1-10% of the mass of the composite.

[0011] Preferably, the polymer compatibilizer is vinyltriethoxysilane or γ-aminopropyltriethoxysilane.

[0012] Preferably, the trace elements include EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese, and the mass ratio of the four is (3-5):(2-4):(1-2):(0.5-1).

[0013] Preferably, the plant-derived synergist is a compound of menthol and carvacrol, with a mass ratio of 1:(0.5-2); it has a synergistic effect of antibacterial, insecticidal, and toxicity-reducing properties.

[0014] This invention also provides a method for preparing a highly stable nutrient solution containing nano-silicon-potassium composites, comprising the following steps: S1. Add the polymer compatibilizer to the first part of water, which accounts for 30-50% of the total mass of deionized water, and disperse it for 20-40 minutes under stirring conditions of 40-60℃ and 300-600rpm to obtain a uniform compatibilizer dispersion. S2. The micronutrient components are added to a second portion of water, which accounts for 20-40% of the total mass of deionized water, in the order of EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese. Each component is completely dissolved before adding the next. The mixture is stirred at 20-25°C until completely dissolved to obtain a clear micronutrient mother liquor. S3. Slowly add the nano-silicon potassium composite powder to the compatibilizer dispersion obtained in step S1, and shear and disperse it at a high speed of 800-1500 rpm for 30-60 minutes to obtain a uniform and stable nano-composite slurry. S4. Under continuous stirring at 300-500 rpm, slowly add the mother liquor of trace elements obtained in step S2 to the nanocomposite slurry obtained in step S3, control the adding speed so that the temperature of the mixing system does not exceed 40℃, and continue stirring for 20-30 minutes after the addition is completed. S5. Add the plant-derived synergist to the mixture obtained in step S4, and add the remaining deionized water to the total volume. Stir and mix at 400-800 rpm for 1-3 hours at room temperature, adjust the pH value to 5.5-6.5, then filter and fill to obtain the highly stable nutrient solution.

[0015] This invention provides the application of the above-mentioned highly stable nutrient solution in the preparation of fertilizers or growth regulators for improving plant stress resistance, preventing and controlling diseases, and reducing heavy metal toxicity.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) The core component of the nutrient solution of the present invention, the nano-silicon-potassium composite, can effectively adsorb and disperse nutrient ions due to its high specific surface area and layered structure, inhibiting the formation and growth of precipitated crystal nuclei. At the same time, specific surface modifiers and polymer compatibilizers work synergistically through steric hindrance and electrostatic repulsion to stabilize the entire system. This results in no visible precipitation after the nutrient solution is sealed and stored at room temperature for more than 180 days, and the crystallization temperature is significantly higher than that of traditional nutrient solutions. In terms of function and efficiency, the composite has the slow-release function of silicon and potassium nutrients, and works synergistically with chelated trace elements to improve nutrient utilization. The introduced plant-derived synergist further endows the product with antibacterial, insect-repellent and plant system resistance-inducing capabilities, realizing the integration of nutrition and protection.

[0017] (2) The silicon-potassium complex helps to passivate the activity of heavy metals in the soil, and the plant-derived synergist can reduce dependence on chemical pesticides, which meets the needs of green agriculture. In terms of industrialization prospects, its preparation method has clear steps and mild and controllable conditions, which facilitates large-scale production and promotion. Detailed Implementation

[0018] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0019] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0020] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0021] Example 1 High-stability nutrient solution, weigh each ingredient according to the following mass percentages: The formula consists of 0.5% nano-silicon-potassium composite, 0.1% polymer compatibilizer, 0.3% trace elements, 0.05% plant-derived synergist, and 100% deionized water. The nano-silicon-potassium composite has a particle size of 10 nm, an interlayer spacing of 0.5 nm, and a specific surface area of ​​100 m². 2 / g; The polymer compatibilizer is vinyltriethoxysilane; The trace elements include EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese, with a mass ratio of 3:2:1:0.5. The plant-derived synergist is a compound of menthol and carvacrol, with a mass ratio of 1:0.5.

[0022] Example 2 High-stability nutrient solution, weigh each ingredient according to the following mass percentages: 5% nano-silicon-potassium composite, 2% polymer compatibilizer, 3% trace elements, 0.2% plant-derived synergist, and 100% deionized water; The nano-silicon-potassium composite has a particle size of 50 nm, an interlayer spacing of 2 nm, and a specific surface area of ​​500 m². 2 / g; The polymer compatibilizer is γ-aminopropyltriethoxysilane; The trace elements include EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese, with a mass ratio of 5:4:2:1. The plant-derived synergist is a compound of menthol and carvacrol, with a mass ratio of 1:2.

[0023] Example 3 High-stability nutrient solution, weigh each ingredient according to the following mass percentages: Nano-silicon-potassium composite 3%, polymer compatibilizer 1%, trace elements 2%, plant-derived synergist 0.1%, deionized water to make up 100%; The nano-silicon-potassium composite has a particle size of 30 nm, an interlayer spacing of 1 nm, and a specific surface area of ​​300 m². 2 / g; The polymer compatibilizer is γ-aminopropyltriethoxysilane; The trace elements include EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese, with a mass ratio of 4:3:1:0.7. The plant-derived synergist is a compound of menthol and carvacrol, with a mass ratio of 1:1.2.

[0024] The above Examples 1-3 were prepared using the following methods. The preparation of nano-silicon-potassium composites includes the following steps: (a) Intercalation pre-support: Layered montmorillonite and an aqueous solution of intercalating agent with a concentration of 2 mol / L were mixed at a mass ratio of 0.5:1 and stirred at 100°C for 7 hours. Then, the mixture was separated, washed and dried to obtain the intercalation product. (b) Exfoliation and dispersion: The intercalated product is dispersed in deionized water at a concentration of 3 wt%, and exfoliated under high-speed shear at 10,000 rpm for 1 hour. After centrifugation, the supernatant is the nanosheet dispersion. (c) Surface modification and composite: Potassium hydroxide and a surface modifier are added to the nanosheet dispersion. The amount of potassium hydroxide added is 20% of the mass of the composite. The surface modifier is a compound of citric acid and polyaspartic acid in a mass ratio of 1:2. The amount added is 5% of the mass of the composite. Ion exchange and surface reaction are carried out at 60°C for 4 hours. Finally, the nano-silicon potassium composite is obtained by drying.

[0025] A method for preparing a highly stable nutrient solution containing nano-silicon-potassium composite includes the following steps: S1. Add the polymer compatibilizer to the first part of water, which accounts for 40% of the total mass of deionized water, and disperse it for 30 minutes under stirring conditions of 50°C and 500 rpm to obtain a uniform compatibilizer dispersion. S2. The micronutrient components are added to the second part of water, which accounts for 30% of the total mass of deionized water, in the order of EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese. Each component is completely dissolved before adding the next one. The mixture is stirred at 22°C until completely dissolved to obtain a clear micronutrient mother liquor. S3. Slowly add the nano-silicon potassium composite powder to the compatibilizer dispersion obtained in step S1, and shear and disperse it at a high speed of 1200 rpm for 50 minutes to obtain a uniform and stable nano-composite slurry. S4. Under continuous stirring at 400 rpm, slowly add the mother liquor of trace elements obtained in step S2 to the nanocomposite slurry obtained in step S3, control the adding speed so that the temperature of the mixing system does not exceed 40°C, and continue stirring for 25 minutes after the addition is completed. S5. Add the plant-derived synergist to the mixture obtained in step S4, and add the remaining deionized water to the total volume. Stir and mix at 600 rpm for 2 hours at room temperature, adjust the pH value to 6, then filter and fill to obtain the highly stable nutrient solution.

[0026] Comparative Example 1 The difference between this comparative example and Example 3 is that the nano-silicon-potassium composite in Example 3 is replaced with nano-montmorillonite that is not modified by citric acid / polyaspartic acid complex and is only treated with potassium silicate. The other components and preparation methods are the same as in Example 3.

[0027] Comparative Example 2 The difference between this comparative example and Example 3 is that ordinary potassium silicate is used instead of the nano-potassium silicate composite.

[0028] Comparative Example 3 The difference between this comparative example and Example 3 is that it does not contain a polymer compatibilizer, while the remaining components / preparation steps are the same as in Example 3.

[0029] Comparative Example 4 The difference between this comparative example and Example 3 is that it does not contain plant-derived synergists, while the remaining components / preparation steps are the same as in Example 3.

[0030] Performance testing 1. Stability Test: a) Stability at room temperature: The samples obtained in Examples 4-6 and Comparative Examples 1-2 were sealed and placed at room temperature (25°C), and the time for precipitation was observed and recorded. The results are shown in Table 1.

[0031] b) High temperature accelerated stability: The above samples were placed in a constant temperature oven at 54℃. After 14 days, they were taken out and cooled to room temperature. The appearance was observed and the precipitation rate (precipitate volume / total volume × 100%) was measured.

[0032] Table 1 Results of nutrient solution stability test

[0033] 2. Functionality Test a) Disease resistance test: Cucumber (a variety susceptible to powdery mildew) was used as the test crop. At the 3-4 leaf stage of seedlings, a water control (CK), comparative examples 1-4, and nutrient solution treatment (Example 3) were set up. Each nutrient solution was diluted 500 times and artificially inoculated with powdery mildew fungus. Foliar spraying was performed 7 days before inoculation, 3 days after inoculation, and 1 day after inoculation, until droplets appeared on both sides of the leaves. The water control was sprayed with an equal volume of water. The disease index was investigated 7 days later, and the control effect was calculated. The results are shown in Table 2.

[0034] b) Heavy metal toxicity reduction test: Chinese cabbage (Shanghai Bok choy) was planted in cadmium-contaminated soil. A water control, comparative examples 1-4, and nutrient solution from Example 3 were used. Each nutrient solution was diluted 200 times and applied as a root irrigation treatment. During the Chinese cabbage's growth period (4 weeks), irrigation was performed regularly and quantitatively with a consistent total irrigation volume. Each treatment was repeated 5 times. The cadmium content in the aboveground parts was measured after harvest. The results are shown in Table 3.

[0035] Table 2 Results of the test on the functional effects of nutrient solution

[0036] Results analysis: The results of Example 3 in this invention demonstrate that the synergistic effect of the nano-silicon-potassium complex and the plant-derived synergist is crucial. Comparative Example 2, using ordinary potassium silicate, showed a control efficacy of only 23.9%, indicating that the resistance base provided by conventional silicon-potassium nutrition is relatively weak. Comparative Example 1, using unmodified nano-montmorillonite, showed a control efficacy of 31.0%, demonstrating that the nanosheet structure itself can more effectively promote silicon deposition and physical barrier formation within the plant, resulting in superior disease resistance compared to the ordinary form. Comparative Example 3 showed a control efficacy of 30.5%, comparable to Comparative Example 1, but significantly lower than Example 3. This indicates that the lack of a polymer compatibilizer led to decreased dispersion stability of the nanoparticles, potentially causing aggregation or sedimentation, reducing the bioavailability of the active ingredient and thus weakening its disease resistance function. Comparative Example 4 showed a control efficacy of 39.3%, higher than Comparative Examples 1, 2, and 3, but still significantly lower than Example 3. This indicates that the menthol / carvacrol complex itself possesses direct antibacterial activity and a strong resistance-inducing signal. Without it, even with an optimized nanocomposite, the best synergistic disease prevention effect cannot be achieved.

[0037] Table 3. Effects of different treatments on cadmium absorption in Chinese cabbage

[0038] Results analysis: The highest Cd content was found in the aboveground parts of the water control (CK) bok choy, indicating that crops can absorb large amounts of available cadmium from the soil without external sources.

[0039] Comparative Example 2 reduced the Cd content from 65.4 mg / kg to 52.1 mg / kg, a reduction of 20.3%. This was mainly due to the co-precipitation effect of silicate on Cd and the limited increase in soil pH, a typical passivation effect of conventional silicon fertilizer. Comparative Example 1 further reduced the Cd content to 48.7 mg / kg, a reduction of 25.5%. Compared to Comparative Example 2, the effect was significantly improved, directly demonstrating that the nanosheet structure itself, with its huge specific surface area and cation exchange capacity, can more effectively adsorb and fix Cd in the soil. 2+This inhibits Cd migration to plants. Nanostructures are the physical basis for achieving efficient toxicity reduction. Comparative Example 3, which does not contain polymer compatibilizers, had a Cd content of 47.2 mg / kg, with a reduction rate similar to Comparative Example 1, but far lower than Example 3. This indicates that the lack of polymer compatibilizers leads to easy aggregation of nanoparticles in nutrient solution and soil, reducing their effective specific surface area and dispersion uniformity in rhizosphere soil, thereby weakening their Cd fixation efficiency. System stability is a necessary condition to ensure the efficient and long-lasting effect of functional components. The results of Comparative Example 4 show that plant-derived synergists indirectly change the form or availability of Cd by affecting plant root exudates or rhizosphere microbial communities; at the same time, they can also synergistically reduce translocation to aboveground parts by enhancing the plant's own ability to isolate heavy metals, thus demonstrating that plant-derived synergists can assist in the overall toxicity reduction effect.

[0040] The 54.4% cadmium absorption reduction rate achieved in Example 3 of this invention is the result of the combined effects of basic adsorption by the nanostructure, enhanced complexation through specific surface modification, the functional guarantee of system stability, and the physiological synergistic effect of plant-derived components. Among these, the nano-silicon-potassium complex serves as the carrier for the toxicity reduction function, and the citric acid / polyaspartic acid complex surface modification is key to achieving its optimal performance.

[0041] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly stable nutrient solution containing a nano-silicon-potassium composite, characterized in that, By weight percentage, it contains the following components: 0.5-5% nano-silicon-potassium complex, 0.1-2% polymer compatibilizer, 0.3-3% trace elements, 0.05-0.2% plant-derived synergist, and other nutrient fertilizer-acceptable adjuvants.

2. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 1, characterized in that, The nano-silicon-potassium composite has a particle size of 10-50 nm and an interlayer spacing of 0.5-2 nm.

3. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 2, characterized in that, The nano-silicon-potassium composite is obtained by intercalation, exfoliation, and surface modification of layered silicate minerals, and has a specific surface area of ​​100-500 m². 2 / g, wherein the surface modifier is a compound of citric acid and polyaspartic acid in a mass ratio of 1:(1.2-2.5).

4. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 3, characterized in that, The preparation method of the nano-silicon-potassium composite includes the following steps: (a) Intercalation pre-support: The layered silicate minerals are mixed with an aqueous solution of the intercalating agent and stirred at 60-120°C for 2-12 hours. Then, the mixture is separated, washed and dried to obtain the intercalated product. (b) Exfoliation and dispersion: The intercalated product is dispersed in water and exfoliated under high-speed shear. After centrifugation, the supernatant is the nanosheet dispersion. (c) Surface modification and composite: Potassium source compound and surface modifier are added to the nanosheet dispersion, and ion exchange and surface reaction are carried out at 40-80℃ for 1-6 hours. Finally, the nano-silicon potassium composite is obtained by drying.

5. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 4, characterized in that, In step (a), the layered silicate minerals are selected from montmorillonite, vermiculite, or palygorskite, and are crushed through a 150-250 mesh sieve; the concentration of the intercalating agent aqueous solution is 0.5-3.0 mol / L, and the intercalating agent is selected from at least one of urea, potassium acetate, alkyl ammonium salts, or polyethylene oxide; the mass ratio of the intercalating agent aqueous solution to the silicate mineral is 0.2-1:1; In step (b), the intercalation product is dispersed in deionized water at a concentration of 1-5 wt% and then exfoliated by high-speed shearing at 8000-15000 rpm for 0.5-2 hours. The potassium source in step (c) is selected from potassium hydroxide, potassium carbonate or potassium silicate, and the amount added is 10-30% of the mass of the composite; the amount of surface modifier added is 1-10% of the mass of the composite.

6. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 1, characterized in that, The polymer compatibilizer is vinyltriethoxysilane or γ-aminopropyltriethoxysilane.

7. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 1, characterized in that, The trace elements include EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese, and the mass ratio of the four is (3-5):(2-4):(1-2):(0.5-1).

8. The highly stable nutrient solution containing nano-silicon-potassium composite as described in claim 1, characterized in that, The plant-derived synergist is a compound of menthol and carvacrol, with a mass ratio of 1:(0.5-2).

9. The method for preparing a highly stable nutrient solution containing nano-silicon-potassium composites as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Add the polymer compatibilizer to the first part of water, which accounts for 30-50% of the total mass of deionized water, and disperse it for 20-40 minutes under stirring conditions of 40-60℃ and 300-600rpm to obtain a uniform compatibilizer dispersion. S2. The trace element components are added to a second part of water, which accounts for 20-40% of the total mass of deionized water, in the order of EDTA chelated calcium, humic acid chelated magnesium, EDTA chelated iron, and humic acid chelated manganese. The mixture is stirred at 20-25°C until completely dissolved to obtain a clear trace element mother liquor. S3. Slowly add the nano-silicon potassium composite powder to the compatibilizer dispersion obtained in step S1, and shear and disperse it at a high speed of 800-1500 rpm for 30-60 minutes to obtain a uniform and stable nano-composite slurry. S4. Under continuous stirring at 300-500 rpm, slowly add the mother liquor of trace elements obtained in step S2 to the nanocomposite slurry obtained in step S3, control the adding speed so that the temperature of the mixing system does not exceed 40℃, and continue stirring for 20-30 minutes after the addition is completed. S5. Add the plant-derived synergist to the mixture obtained in step S4, and add the remaining deionized water to the total volume. Stir and mix at 400-800 rpm for 1-3 hours at room temperature, adjust the pH value to 5.5-6.5, then filter and fill to obtain the highly stable nutrient solution.

10. The use of the highly stable nutrient solution according to any one of claims 1-8 in the preparation of fertilizers or growth regulators for improving plant stress resistance, preventing and controlling diseases and reducing heavy metal toxicity.

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