Macroelement water-soluble fertilizer suspending agent and preparation method thereof

Abstract

The invention relates to the technical field of suspending agent preparation, and discloses a macroelement water-soluble fertilizer suspending agent, which comprises macroelements, medium trace elements, a suspending agent and an auxiliary agent, and a preparation method of the macroelement water-soluble fertilizer suspending agent comprises the following steps of: preparing the macroelement water-soluble fertilizer suspending agent; the preparation method comprises the following steps: S1, raw material pretreatment, S2, macroelement dissolution, S3, medium trace element addition, S4, suspending agent and auxiliary agent addition, S5, fine treatment, and S6, packaging and storage, the stability of the suspending agent is significantly enhanced: a more stable suspension system is constructed by precisely adjusting the ratio of xanthan gum to the sodium carboxymethyl cellulose suspending agent, and the unique component proportion enables the fertilizer to have a better effect after the fertilizer is stored for 6 months. The nutrient precipitation rate can still be kept below 5%, the uniformity of the fertilizer in the storage and transportation process is effectively guaranteed, farmers do not need to worry about uneven fertilization caused by nutrient precipitation in the application process, it is guaranteed that crops can continuously and evenly absorb nutrients, and healthy growth is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of suspension agent preparation, specifically to a suspension agent for water-soluble fertilizers of macronutrients and a preparation method thereof. Background Art

[0002] In modern agricultural production, suspension agents for water-soluble fertilizers of macronutrients are increasingly widely used due to their advantage of quickly supplementing key nutrient elements such as nitrogen, phosphorus, and potassium for crops. However, there are many technical bottlenecks in the practical application of such fertilizer suspension agents at present:

[0003] Poor stability: In traditional suspension agents for water-soluble fertilizers of macronutrients, each nutrient component is prone to precipitation and stratification due to the action of gravity. The selection and proportioning of the suspension agent are unreasonable, resulting in difficulty in maintaining the suspended state for a long time. For example, in some products, the nutrient precipitation rate is as high as 15 - 20% after 3 months of storage, seriously affecting the uniformity of the fertilizer and the stability of fertilizer efficiency, making the nutrient absorption by crops uneven after application and affecting growth and development.

[0004] Insufficient nutrient uniformity: Due to the lack of scientific preparation processes and suitable dispersion technologies, macronutrients, micronutrients, and various additives are difficult to be fully and evenly dispersed in the fertilizer system. This results in large differences in nutrient content in different parts of the fertilizer. Even if farmers stir during the application process, it is difficult to ensure consistent nutrient supply each time, leading to uneven crop growth, reducing the overall yield and quality.

[0005] Limited adaptability to different crops: Different crops have different requirements for the pH value of fertilizers, the form of nutrient elements, etc. The existing pH value range of suspension agents for water-soluble fertilizers of macronutrients is narrow and the adjustment is unreasonable. The pH value of some products is too high or too low, which will stimulate the crop roots and affect the normal physiological functions of the roots, such as hindering nutrient absorption and inhibiting root respiration. At the same time, micronutrients are mostly added in the form of simple inorganic salts, with low stability and absorption utilization rate, and cannot meet the high-efficiency absorption requirements of different crops for specific elements.

[0006] Weak resistance to environmental interference: In some areas with complex climatic conditions, especially in low-temperature environments, traditional suspension agents for water-soluble fertilizers of macronutrients are prone to icing due to the lack of effective antifreeze components or improper addition ratio. Icing will damage the original structure of the fertilizer, resulting in nutrient loss and changes in physical properties. After thawing, the suspension performance and nutrient availability of the fertilizer are greatly reduced, affecting normal application and fertilizer efficiency. Summary of the Invention

[0007] (I) Technical Problems to be Solved

[0008] In view of the deficiencies of the prior art, the present invention provides a suspension agent for water-soluble fertilizers containing macro elements and a preparation method thereof, which has the advantages of significantly enhanced stability, etc., and solves the problem of poor stability: in traditional suspension agents for water-soluble fertilizers containing macro elements, each nutrient component is prone to precipitation and stratification due to the action of gravity.

[0009] (II) Technical Solution

[0010] To achieve the above-mentioned purpose of significantly enhanced stability, the present invention provides the following technical solution: a suspension agent for water-soluble fertilizers containing macro elements, including macro elements, medium and trace elements, a suspension agent and auxiliaries. The macro elements include:

[0011] Nitrogen (N): 15 - 25%, selecting nitrogen-containing compounds such as urea and ammonium nitrate. Among them, the nitrogen content of urea is 46%, and the nitrogen content of ammonium nitrate is 35%. Urea can provide a long-term nitrogen source for crops, and ammonium nitrate can quickly supplement nitrogen.

[0012] Phosphorus (P2O5): 10 - 20%, mainly using potassium dihydrogen phosphate and monoammonium phosphate. The phosphorus (P2O5) content of potassium dihydrogen phosphate is 52%, which can effectively promote the root growth and flower bud differentiation of crops.

[0013] Potassium (K2O): 15 - 30%, preferably potassium sulfate and potassium nitrate. The potassium (K2O) content of potassium nitrate is 46%, which helps to enhance the stress resistance of crops and improve the fruit quality.

[0014] Among them, the medium and trace elements include:

[0015] Calcium (Ca): 1 - 3%, using chelated calcium such as EDTA-Ca to improve the stability and absorption utilization rate of calcium.

[0016] Magnesium (Mg): 0.5 - 2%, using magnesium sulfate to provide an important supplement for crop photosynthesis.

[0017] Zinc (Zn): 0.1 - 0.5%, added in the form of EDTA-Zn to promote the synthesis of crop growth hormones.

[0018] Iron (Fe): 0.1 - 0.5%, such as EDDHA-Fe, to prevent iron deficiency chlorosis in crops.

[0019] Among them, the suspension agent and auxiliaries include:

[0020] Suspension agent: xanthan gum 0.3 - 0.8%, sodium carboxymethyl cellulose 0.2 - 0.6%, to enhance the suspension stability and prevent nutrient precipitation.

[0021] Dispersant: sodium lignin sulfonate 0.1 - 0.3%, to uniformly disperse each component.

[0022] pH regulator: citric acid or potassium hydroxide, which adjusts the pH value to 5.5 - 6.5 to ensure the stability and effectiveness of the fertilizer, while reducing the stimulation to the crop roots;

[0023] Antifreeze: 2 - 5% ethylene glycol, which reduces the freezing point of the solution and prevents the fertilizer from freezing and being damaged in a low-temperature environment.

[0024] Preferably, the preparation method of the water-soluble fertilizer suspension for macronutrients includes the following method steps,

[0025] S1 Raw material pretreatment, S2 Dissolution of macronutrients, S3 Addition of micronutrients and trace elements, S4 Addition of suspending agent and auxiliary agents, S5 Fine treatment, and S6 Packaging and storage.

[0026] Preferably, in the S1 raw material pretreatment: the macronutrient raw materials such as urea, ammonium nitrate, potassium dihydrogen phosphate, and potassium sulfate are crushed and passed through a 80 - 100 mesh sieve to ensure that the particles are small and uniform, which is beneficial for subsequent dissolution;

[0027] Chelates of micronutrients and trace elements such as EDTA-Ca and EDTA-Zn are accurately weighed and reserved according to the proportion.

[0028] Preferably, in the S2 dissolution of macronutrients: an appropriate amount of deionized water is added to the reaction kettle, the stirring device is started, and the stirring speed is controlled at 150 - 200 r / min;

[0029] The crushed macronutrient raw materials are added slowly in sequence. First, add ammonium nitrate and urea nitrogen fertilizers. After complete dissolution, then add potassium dihydrogen phosphate phosphate fertilizer, and finally add potassium sulfate potassium fertilizer. Control the temperature of the reaction kettle at 40 - 50 °C to accelerate the dissolution process and avoid nutrient decomposition caused by high temperature at the same time.

[0030] Preferably, in the S3 addition of micronutrients and trace elements: after the macronutrients are completely dissolved and the solution temperature drops to 30 - 35 °C, the weighed chelates of micronutrients and trace elements are slowly added to the reaction kettle, and continue to stir for 30 - 40 minutes to make the micronutrients and trace elements evenly dispersed in the solution.

[0031] Preferably, in the S4 addition of suspending agent and auxiliary agents: first, xanthan gum and sodium carboxymethyl cellulose suspending agent are mixed with a small amount of deionized water to form a uniform paste, and then slowly added to the reaction kettle. At the same time, the stirring speed is increased to 250 - 300 r / min, and continue to stir for 40 - 60 minutes to make the suspending agent fully play its role;

[0032] Add sodium lignosulfonate dispersant and stir for 20 - 30 minutes to ensure that all components are evenly dispersed;

[0033] Use citric acid or potassium hydroxide to adjust the pH value of the solution to 5.5 - 6.5, add while stirring, and monitor the change of pH value in real time;

[0034] Finally, add ethylene glycol antifreeze and stir evenly for 15-20 minutes.

[0035] Preferably, the S5 fine treatment: grinding the prepared suspension by a colloid mill for 2-3 times to further refine the particles so that the particle size reaches 1-5 μm, thereby improving the stability of the suspension and the nutrient absorption efficiency;

[0036] The ground suspension is filtered through a 1-5 μm precision filter to remove possible impurity particles and ensure product quality.

[0037] Preferably, the S6 packaging and storage: the filtered macronutrient water-soluble fertilizer suspension is placed in a sealed container to avoid contact with air, prevent microbial contamination and nutrient oxidation;

[0038] Store in a cool, dry place at 5-25°C, avoid direct sunlight and high temperature environment to ensure the stability and effectiveness of the product.

[0039] (III) Beneficial effects

[0040] Compared with the prior art, the present invention provides a large amount of element water-soluble fertilizer suspension and a preparation method thereof, which has the following beneficial effects:

[0041] 1. The macro-element water-soluble fertilizer suspension and preparation method thereof, wherein the stability of the suspension is significantly enhanced: a more stable suspension system is constructed by precisely adjusting the ratio of xanthan gum and sodium carboxymethyl cellulose suspension, and the unique ingredient ratio enables the nutrient precipitation rate of the fertilizer to remain below 5% after 6 months of storage, thereby effectively ensuring the uniformity of the fertilizer during storage and transportation. Farmers do not need to worry about uneven fertilization due to nutrient precipitation when applying the fertilizer, thereby ensuring that crops can continuously and evenly absorb nutrients and promote healthy growth.

[0042] 2. The macro-element water-soluble fertilizer suspension and its preparation method. The nutrient uniformity of the suspension is greatly improved: the sophisticated preparation process covers the precise pretreatment of raw materials, strict temperature and stirring speed control when adding each component, and subsequent colloid mill grinding and precision filtration. These steps ensure that the macro-elements, trace elements and additives are fully and evenly dispersed, and the nutrient distribution in the fertilizer system is highly consistent. According to testing, the nutrient content in different parts of the product is very small, which ensures that each fertilization can provide balanced and sufficient nutrition for crops, significantly improves the uniformity and consistency of crop growth, and helps to improve the overall yield and quality.

[0043] 3. The suspension of macronutrient water-soluble fertilizer and its preparation method have comprehensively optimized adaptability: on the one hand, the pH value is precisely adjusted to the reasonable range of 5.5 - 6.5, reducing the stimulation to the roots of different crops, creating a suitable growth environment for the roots, facilitating the absorption of nutrients by the roots and the normal exertion of physiological functions. On the other hand, chelated medium and micronutrients such as EDTA-Ca and EDDHA-Fe are used, greatly improving the stability and absorption utilization rate of the elements, better meeting the special needs of various crops for different medium and micronutrients, and expanding the scope of applicable crops of the fertilizer.

[0044] 4. The suspension of macronutrient water-soluble fertilizer and its preparation method have significantly improved stress resistance: ethylene glycol is added as an antifreeze agent, effectively reducing the freezing point of the fertilizer solution, enabling it to adapt to a wider temperature environment. Especially in low-temperature regions, it can prevent the fertilizer from freezing and being damaged in winter or cold seasons. At the same time, appropriate pH value adjustment also enhances the adaptability of the fertilizer to different soil acid-base environments, reducing the adverse effects of soil factors on fertilizer efficiency, ensuring that the fertilizer can stably and effectively play its role under complex environmental conditions, and providing a more reliable fertilization guarantee for agricultural production. Detailed implementation mode

[0045] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] This solution provides a technical solution, specifically, a suspension of macronutrient water-soluble fertilizer, including

[0047] Macronutrients:

[0048] Nitrogen (N): 15 - 25%, urea and ammonium nitrate nitrogen-containing compounds are selected. Among them, the nitrogen content of urea is 46%, and the nitrogen content of ammonium nitrate is 35%. Urea can provide a long-term nitrogen source for crops, and ammonium nitrate can quickly supplement nitrogen.

[0049] Phosphorus (P2O5): 10 - 20%, mainly potassium dihydrogen phosphate and monoammonium phosphate are used. The phosphorus (P2O5) content of potassium dihydrogen phosphate is 52%, which can effectively promote the root growth and flower bud differentiation of crops.

[0050] Potassium (K2O): 15 - 30%, such as potassium sulfate and potassium nitrate. The potassium (K2O) content of potassium nitrate is 46%, which helps to enhance the stress resistance of crops and improve the fruit quality.

[0051] Medium and micronutrients:

[0052] Calcium (Ca): 1 - 3%, using chelated calcium such as EDTA-Ca to improve the stability and absorption utilization rate of calcium element;

[0053] Magnesium (Mg): 0.5 - 2%, using magnesium sulfate to provide an important supplement for crop photosynthesis;

[0054] Zinc (Zn): 0.1 - 0.5%, added in the form of EDTA-Zn to promote the synthesis of crop growth hormones;

[0055] Iron (Fe): 0.1 - 0.5%, such as EDDHA-Fe, to prevent iron deficiency chlorosis in crops;

[0056] Suspending agent and additives:

[0057] Suspending agent: xanthan gum 0.3 - 0.8%, sodium carboxymethyl cellulose 0.2 - 0.6%, to enhance suspension stability and prevent nutrient precipitation;

[0058] Dispersant: sodium lignosulfonate 0.1 - 0.3%, to evenly disperse each component;

[0059] pH regulator: citric acid or potassium hydroxide, to adjust the pH value to 5.5 - 6.5, ensure the stability and effectiveness of the fertilizer, and at the same time reduce the stimulation to crop roots;

[0060] Antifreeze: ethylene glycol 2 - 5%, to lower the freezing point of the solution and prevent the fertilizer from freezing and being damaged in low-temperature environments;

[0061] Furthermore, the preparation method of the water-soluble fertilizer suspending agent for macronutrients includes the following method steps.

[0062] S1 Raw material pretreatment:

[0063] Crush the raw materials of macronutrients such as urea, ammonium nitrate, potassium dihydrogen phosphate, and potassium sulfate, and pass through an 80 - 100 mesh sieve to ensure that the particles are small and uniform, which is beneficial for subsequent dissolution;

[0064] Weigh the chelates of medium and trace elements such as EDTA-Ca and EDTA-Zn accurately according to the ratio and set aside for use;

[0065] S2 Dissolution of macronutrients:

[0066] Add an appropriate amount of deionized water to the reaction kettle, start the stirring device, and control the stirring speed at 150 - 200 r / min;

[0067] Slowly add the crushed macronutrient raw materials in sequence. First add ammonium nitrate and urea nitrogen fertilizers. After complete dissolution, then add potassium dihydrogen phosphate phosphate fertilizer, and finally add potassium sulfate potassium fertilizer. Control the temperature of the reaction kettle at 40 - 50 °C to accelerate the dissolution process and avoid nutrient decomposition caused by high temperature;

[0068] Addition of medium and trace elements in S3:

[0069] After the macronutrients are completely dissolved and the solution temperature drops to 30 - 35 °C, slowly add the weighed medium and trace element chelates into the reaction kettle, and continue stirring for 30 - 40 minutes to evenly disperse the medium and trace elements in the solution;

[0070] Addition of suspending agent and additives in S4:

[0071] First, mix xanthan gum and sodium carboxymethyl cellulose suspending agent with a small amount of deionized water to make a uniform paste, then slowly add it into the reaction kettle. At the same time, increase the stirring speed to 250 - 300 r / min and continuously stir for 40 - 60 minutes to allow the suspending agent to fully play its role;

[0072] Add sodium lignosulfonate dispersant and stir for 20 - 30 minutes to ensure that all components are evenly dispersed;

[0073] Use citric acid or potassium hydroxide to adjust the pH value of the solution to 5.5 - 6.5, add while stirring, and monitor the change of pH value in real time;

[0074] Finally, add ethylene glycol antifreeze and stir evenly for 15 - 20 minutes;

[0075] Fine treatment in S5:

[0076] Grind the prepared suspension through a colloid mill for 2 - 3 times to further refine the particles, so that the particle size reaches 1 - 5 μm, improving the stability of the suspending agent and the nutrient absorption efficiency;

[0077] Filter the ground suspension through a precision filter with a pore size of 1 - 5 μm to remove possible impurity particles and ensure the product quality;

[0078] Packaging and storage in S6:

[0079] Fill the filtered macronutrient water-soluble fertilizer suspension into a sealed container to avoid contact with air, prevent microbial contamination and nutrient oxidation;

[0080] Store in a cool and dry place, with the temperature controlled at 5 - 25 °C, avoiding direct sunlight and high-temperature environment to ensure the stability and effectiveness of the product;

[0081] Furthermore, the stability of the suspending agent is significantly enhanced: by precisely adjusting the ratio of xanthan gum and sodium carboxymethyl cellulose suspending agent, a more stable suspension system is constructed. The unique ingredient ratio enables the nutrient precipitation rate to remain below 5% after 6 months of storage of the fertilizer, effectively ensuring the uniformity of the fertilizer during storage and transportation. Farmers do not need to worry about uneven fertilization caused by nutrient precipitation during application, ensuring that crops can continuously and evenly absorb nutrients and promote healthy growth;

[0082] Furthermore, the nutrient uniformity of this suspending agent has been greatly improved: The refined preparation process covers precise pretreatment of raw materials, strict control of temperature and stirring speed during the addition of each component, as well as subsequent colloid mill grinding and precision filtration steps. These steps promote the full and uniform dispersion of macronutrients, medium and micronutrients, and additives. The nutrient distribution within the fertilizer system is highly consistent. After testing, the nutrient content differences in different parts of the product are extremely small, ensuring that each fertilization can provide balanced and sufficient nutrition for crops, significantly improving the uniformity and consistency of crop growth, and contributing to the improvement of overall yield and quality.

[0083] Furthermore, the adaptability of this suspending agent has been comprehensively optimized: On the one hand, the pH value is precisely adjusted to the reasonable range of 5.5 - 6.5, reducing the stimulation to the roots of different crops, creating a suitable growth environment for the roots, facilitating the absorption of nutrients by the roots and the normal exertion of physiological functions. On the other hand, chelated medium and micronutrients such as EDTA-Ca and EDDHA-Fe are used, greatly improving the stability and absorption utilization rate of the elements, being able to better meet the special requirements of various crops for different medium and micronutrients, and expanding the range of applicable crops for the fertilizer.

[0084] Furthermore, the stress resistance of this preparation method has been significantly improved: Ethylene glycol is added as an antifreeze agent, effectively reducing the freezing point of the fertilizer solution, enabling it to adapt to a wider temperature environment. Especially in low-temperature regions, it can prevent the fertilizer from freezing and being damaged in winter or cold seasons. At the same time, appropriate pH value adjustment also enhances the adaptability of the fertilizer to different soil acid-base environments, reducing the adverse effects of soil factors on fertilizer efficiency, and ensuring that the fertilizer can stably and effectively play its role under complex environmental conditions, providing a more reliable fertilization guarantee for agricultural production.

[0085] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Water-soluble fertilizer suspension for macronutrients, comprising macronutrients, medium and micronutrients, a suspending agent and additives, characterized in that: The macronutrients include: Nitrogen (N): 15 - 25%, selecting nitrogen-containing compounds such as urea and ammonium nitrate. Among them, urea contains 46% nitrogen and ammonium nitrate contains 35% nitrogen. Urea can provide a long-acting nitrogen source for crops, and ammonium nitrate can quickly supplement nitrogen. Phosphorus (P2O5): 10 - 20%, mainly using potassium dihydrogen phosphate and monoammonium phosphate. Potassium dihydrogen phosphate contains 52% phosphorus (P2O5), which can effectively promote the root growth and flower bud differentiation of crops. Potassium (K2O): 15 - 30%, preferably potassium sulfate and potassium nitrate. Potassium nitrate contains 46% potassium (K2O), which helps to enhance the stress resistance of crops and improve the fruit quality. Among them, the micronutrients include: Calcium (Ca): 1 - 3%, using chelated calcium such as EDTA-Ca to improve the stability and absorption utilization rate of calcium. Magnesium (Mg): 0.5 - 2%, using magnesium sulfate to provide an important supplement for crop photosynthesis. Zinc (Zn): 0.1 - 0.5%, added in the form of EDTA-Zn to promote the synthesis of crop growth hormones. Iron (Fe): 0.1 - 0.5%, such as EDDHA-Fe, to prevent iron deficiency chlorosis in crops. Among them, the suspending agent and additives include: Suspending agent: xanthan gum 0.3 - 0.8%, sodium carboxymethyl cellulose 0.2 - 0.6%, enhancing the suspension stability and preventing nutrient precipitation. Dispersant: sodium lignosulfonate 0.1 - 0.3%, making each component evenly dispersed. pH regulator: citric acid or potassium hydroxide, adjusting the pH value to 5.5 - 6.5 to ensure the stability and effectiveness of the fertilizer, and at the same time reducing the stimulation to crop roots. Antifreeze: ethylene glycol 2 - 5%, reducing the freezing point of the solution to prevent the fertilizer from freezing and being damaged in a low-temperature environment.

2. Preparation method of a suspension fertilizer for macronutrients, characterized in that: It includes the following method steps: S1 raw material pretreatment, S2 macronutrient dissolution, S3 micronutrient addition, S4 suspending agent and additive addition, S5 fine treatment, and S6 packaging and storage.

3. The preparation method of the macronutrient water-soluble fertilizer suspending agent according to claim 2, characterized in that: The S1 raw material pretreatment: crushing the macronutrient raw materials of urea, ammonium nitrate, potassium dihydrogen phosphate, and potassium sulfate, and passing through an 80 - 100 mesh sieve to ensure that the particles are small and uniform, which is beneficial for subsequent dissolution. Chelates of micronutrients such as EDTA-Ca and EDTA-Zn are accurately weighed and reserved according to the proportion.

4. The preparation method of the macroelement water-soluble fertilizer suspending agent according to claim 2, characterized in that: The S2 macronutrient dissolution: adding an appropriate amount of deionized water to the reaction kettle, starting the stirring device, and controlling the stirring speed at 150 - 200 r / min. Sequentially and slowly add the crushed macronutrient raw materials. First add ammonium nitrate and urea nitrogen fertilizers. After complete dissolution, then add potassium dihydrogen phosphate phosphate fertilizer, and finally add potassium sulfate potassium fertilizer. Control the temperature of the reaction kettle at 40 - 50 °C to accelerate the dissolution process and avoid nutrient decomposition caused by high temperature.

5. The preparation method of the suspension of macronutrient water-soluble fertilizer according to claim 2, characterized in that: The S3 micronutrient addition: after the macronutrients are completely dissolved and the solution temperature drops to 30 - 35 °C, slowly add the weighed micronutrient chelates into the reaction kettle and continue stirring for 30 - 40 minutes to make the micronutrients evenly dispersed in the solution.

6. The preparation method of the suspension of the macronutrient water-soluble fertilizer according to claim 2, characterized in that: Addition of the S4 suspending agent and additives: First, mix xanthan gum, sodium carboxymethyl cellulose suspending agent with a small amount of deionized water to form a uniform paste, and then slowly add it to the reaction kettle while increasing the stirring speed to 250 - 300 r / min and continuously stirring for 40 - 60 minutes to allow the suspending agent to fully play its role; Add sodium lignosulfonate dispersant and stir for 20 - 30 minutes to ensure uniform dispersion of each component; Use citric acid or potassium hydroxide to adjust the pH value of the solution to 5.5 - 6.5, add while stirring, and monitor the change of pH value in real time; Finally, add ethylene glycol antifreeze and stir evenly for 15 - 20 minutes.

7. The preparation method of the suspension of the macronutrient water-soluble fertilizer according to claim 2, characterized in that: The S5 fine treatment: Grind the prepared suspension through a colloid mill for 2 - 3 times to further refine the particles so that the particle size reaches 1 - 5 μm, improving the stability of the suspending agent and the nutrient absorption efficiency; Filter the ground suspension through a precision filter with a pore size of 1 - 5 μm to remove possible impurity particles and ensure product quality.

8. The preparation method of the suspension of macronutrient water-soluble fertilizer according to claim 2, characterized in that: The S6 packaging and storage: Fill the filtered water-soluble fertilizer suspending agent of macronutrients into a sealed container to avoid contact with air and prevent microbial contamination and nutrient oxidation; Store in a cool and dry place with the temperature controlled at 5 - 25 °C, avoiding direct sunlight and high-temperature environment to ensure the stability and effectiveness of the product.