An agricultural automatic dispersion type multi-component complex herbicide composition and a preparation method thereof

Abstract

The application discloses an agricultural automatic dispersion type multi-element compounded herbicide composition and a preparation method thereof, and belongs to the technical field of pesticide herbicides. The composition is prepared from dithiopyr potassium salt, nicosulfuron potassium salt, carfentrazone ethyl potassium salt, maleic anhydride esterified starch grafting acrylic acid-styrene sodium sulfonate copolymer, polyacrylic acid sodium salt, naphthalene sulfonate formaldehyde condensate, sodium lignosulfonate, fatty alcohol sulfonate or fatty alcohol sulfate and a filler. The three herbicides with complementary action mechanisms are compounded in the form of potassium salt, broadleaf weeds and gramineous weeds can be effectively prevented and removed at the same time; through construction of a multi-level composite dispersant system, rapid automatic disintegration and dispersion of the granules after water is met are realized; and the pre-potassium salt treatment improves water solubility and dispersion uniformity of active ingredients. The herbicide has the advantages of excellent automatic dispersion performance, high-efficiency herbicidal performance, environmental protection and the like.

Description

Technical Field

[0001] This invention relates to the field of pesticide and herbicide technology, and in particular to an agricultural self-dispersing multi-component compound herbicide composition and its preparation method. Background Technology

[0002] In recent years, the limited variety and long-term, extensive use of conventional corn herbicides has led to significant resistance in some weeds. Simultaneously, with changes in the weed population, some weeds that are poorly controlled by conventional corn herbicides have gradually become major pests, posing a prominent problem for growers. Taking the summer corn growing area of ​​the Huang-Huai-Hai Plain as an example, late-season application of corn herbicides has become commonplace in the past two years, but the problem remains unresolved: on the one hand, the effectiveness is generally limited; on the other hand, some weeds emerge late, missing the optimal control period, making application extremely inconvenient once the corn canopy closes. Furthermore, with the advancement of land transfer and the increasing prevalence of mechanized farming, some climbing weeds become entangled in corn plants during the harvest season, severely interfering with the efficiency of mechanized operations.

[0003] Dicamba belongs to the benzoic acid family of herbicides (benzoic acid derivatives). It has systemic action and is used in fields of gramineous crops such as corn to control various broadleaf weeds, including crabgrass, lambsquarters, field bindweed, thistle, and horsetail. When sprayed post-emergence, the herbicide is absorbed through the stems, leaves, and roots of the weeds, and is translocated up and down the phloem and xylem, inhibiting the normal activity of plant hormones, thus killing the weeds. Dicamba has advantages such as rapid weed killing and safety for crops and subsequent crops with no residue. However, it also has significant drawbacks: it can easily cause phytotoxicity under low-temperature conditions, and it is essential to prevent the herbicide from drifting onto other sensitive crops.

[0004] Nicosulfuron is a systemic herbicide that can be absorbed by the stems, leaves, and roots of weeds. It is translocated within the plant, causing sensitive plants to experience growth stagnation, chlorosis of stems and leaves, and eventual death, typically within 20-25 days. This herbicide is most effective when applied to corn before the 4-leaf stage; its efficacy decreases as seedlings grow larger. It possesses some pre-emergence herbicidal activity, but this activity is far lower than post-emergence activity. With prolonged use, some weeds have developed resistance to nicosulfuron.

[0005] Benzopyrazole is a representative product of the benzoylpyrazole class of herbicides, specifically used for post-emergence control of grasses and broadleaf weeds in cornfields. It is renowned for its extremely high safety, broad spectrum of weed control, and effectiveness against resistant weeds, and is often used as an upgraded option when cornfields encounter nicosulfuron-resistant weeds. However, it has the following drawbacks: First, its efficacy is unstable and greatly affected by temperature. The optimal application temperature is 18-28℃; outside this range, its effectiveness decreases, and it is prone to volatilization at high temperatures. Second, it is highly dependent on humidity; under drought conditions, a significant increase in water usage is required. If it rains within 4 hours of application, re-application is necessary, and continuous heavy rain may cause leaching of the herbicide. Third, its residual effect is relatively short, requiring precise application at the 3-5 leaf stage of weeds. Fourth, under drought conditions, systemic translocation is hindered, significantly reducing its efficacy.

[0006] Therefore, developing a novel herbicide composition that can simultaneously carry three active ingredients—dicamba, nicosulfuron, and benzoxazine—possesses excellent autodispersibility and formulation stability, and has an environmentally friendly and efficient preparation process is of significant practical importance and market value. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art by proposing an agricultural auto-dispersible multi-component compound herbicide composition and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An agricultural auto-dispersible multi-component compound herbicide composition, by weight, is made of the following components: 10-50 parts of dicamba potassium salt, 1-10 parts of nicosulfuron potassium salt, 1-20 parts of benzoyl sulfone potassium salt, 15-20 parts of maleic anhydride esterified starch-grafted acrylic acid-styrene sulfonate copolymer, 3-10 parts of sodium polyacrylate, 3-10 parts of naphthalene sulfonate formaldehyde condensate, 3-10 parts of sodium lignin sulfonate, 2-5 parts of fatty alcohol sulfonate or fatty alcohol sulfate, and 5-30 parts of filler.

[0010] Preferably, the preparation method of the potassium dicamba salt is as follows: 100 parts of dicamba and 30-40 parts of potassium carbonate are mixed for 10-15 minutes, 15-20 parts of deionized water are added, and the mixture is stirred for 15-20 minutes. The mixture is then granulated into particles with a diameter of 0.4-3.0 mm using extrusion granulation, followed by boiling drying with an inlet air temperature of 60-80℃. The moisture content of the output product is maintained at 1.5-5%. The dried particles are collected to obtain the potassium dicamba salt.

[0011] Preferably, the preparation method of the nicosulfuron potassium salt is as follows: 100 parts of nicosulfuron and 16-20 parts of potassium carbonate are mixed for 10-15 minutes, 15-20 parts of deionized water are added, and the mixture is stirred for 15-20 minutes. The mixture is then granulated into particles with a diameter of 0.4-3.0 mm using extrusion granulation, followed by boiling drying with an inlet air temperature of 60-80℃. The moisture content of the output product is maintained at 1.5-5%. The dried particles are collected to obtain nicosulfuron potassium salt.

[0012] Preferably, the preparation method of the benzoxazine potassium salt is as follows: 100 parts of benzoxazine and 20-25 parts of potassium carbonate are mixed for 10-15 minutes, 15-20 parts of deionized water are added, and the mixture is stirred for 15-20 minutes. The mixture is then granulated into particles with a diameter of 0.4-3.0 mm by extrusion granulation, followed by boiling drying with an inlet air temperature of 60-80℃. The moisture content of the output product is maintained at 1.5-5%. The dried particles are collected to obtain benzoxazine potassium salt.

[0013] Preferably, the filler is a mixture of corn starch and potassium carbonate in a mass ratio of 2-5:1.

[0014] Preferably, the preparation method of the maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate sodium copolymer is as follows:

[0015] A1. Disperse the dried corn starch in deionized water to prepare a 20-30 wt% starch suspension. Add anhydrous sodium carbonate and stir at 200-300 rpm for 25-35 min at room temperature. Adjust the pH to neutral with 8-10% dilute hydrochloric acid, filter, wash 2-3 times with deionized water, and vacuum dry at 45-55℃ for 12-24 h to obtain pretreated corn starch.

[0016] A2. The pretreated corn starch obtained in A1 was dispersed in anhydrous N,N-dimethylformamide (DMF), maleic anhydride was added, and the mixture was heated to 60-70℃ and stirred at 200-300 rpm for 5-6 hours under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the resulting solid was washed 2-3 times with anhydrous ethanol and 2-3 times with deionized water. Then, it was vacuum dried at 45-55℃ for 12-24 hours, pulverized, and passed through a 100-150 mesh sieve to obtain esterified modified starch. The reaction equation is as follows:

[0017]

[0018] A3. Disperse the esterified modified starch obtained in A2 in deionized water to prepare a 10-15 wt% esterified modified starch suspension. Stir at 55-65℃ and 200-400 rpm for 25-35 min. Adjust the pH of the esterified modified starch aqueous solution to 6.5-7.0 with 8-10% sodium hydroxide aqueous solution. Under nitrogen protection, raise the temperature to 75-85℃, add 1-2 wt% ammonium persulfate (APS) aqueous solution, and stir for 15-20 min. Then, slowly and uniformly add a mixture of acrylic acid and sodium styrene sulfonate over 2-3 h. A 20-30 wt% aqueous solution of mixed monomers was added dropwise. After the addition was complete, the mixture was kept at 75-85℃ for 2-3 hours. After the reaction was completed, the mixture was cooled to room temperature and allowed to stand in anhydrous ethanol for 1-2 hours, resulting in the precipitation of a white precipitate. The precipitate was filtered, and the resulting filter cake was washed 2-3 times with a 70-80% aqueous solution of anhydrous ethanol, and then washed 1-2 times with anhydrous ethanol. The solid was collected and vacuum dried at 45-55℃ for 12-24 hours. After pulverizing, the solid was passed through a 150-200 mesh sieve to obtain the maleic anhydride esterified starch-grafted acrylic acid-styrene sulfonate copolymer. The reaction equation is as follows:

[0019]

[0020] In step A1, anhydrous sodium carbonate pretreats corn starch. This process moderately swells the starch granules, disrupts some crystalline regions, and improves the uniformity of subsequent reactions. Furthermore, the weakly alkaline environment provided by sodium carbonate converts some hydroxyl groups on the starch molecules into more nucleophilic starch anions, significantly enhancing the activity of the esterification reaction. After neutralization with dilute hydrochloric acid, washing, and drying, activated pretreated starch is obtained. In step A2, the pretreated starch is dispersed in anhydrous DMF. DMF can both swell starch and dissolve maleic anhydride. Under nitrogen protection at 60-70℃, the starch hydroxyl groups act as nucleophiles, undergoing a nucleophilic addition-ring-opening reaction on the carbonyl carbon of maleic anhydride to generate starch-maleic acid monoester. This reaction is reversible, but a significant excess of maleic anhydride and the anhydrous environment shift the equilibrium to the right, ultimately introducing a side chain containing an active carbon-carbon double bond into the starch backbone via an ester bond. In step A3, the esterified modified starch is dispersed in water under weakly alkaline conditions (pH...). (6.5-7.0) Further swelling of starch facilitates the diffusion of monomers and initiators. After heating to 75-85℃, the added ammonium persulfate thermally decomposes to generate sulfate radicals. These primary radicals preferentially attack the double bonds of maleic acid residues on the starch side chains. Through radical addition or abstraction of allylic hydrogen, stable starch macromolecular radicals are generated on the starch backbone. Subsequently, the carbon-carbon double bonds in the mixed monomers of acrylic acid and sodium styrene sulfonate are sequentially inserted into the macromolecular radicals, resulting in a chain growth reaction and forming a graft copolymer with starch as the main chain and random copolymer of acrylic acid and sodium styrene sulfonate as the side chain.

[0021] Preferably, the weight-average molecular weight of the corn starch in A1 is 1×10⁻⁶. 6 -1×10 7 Da, with a mass fraction of 24-28% amylose.

[0022] Preferably, the amount of anhydrous sodium carbonate in A1 is 2-5% of the mass of corn starch.

[0023] Preferably, the ratio of corn starch to N,N-dimethylformamide in A2 is 1g:3-5ml.

[0024] Preferably, the mass ratio of corn starch to maleic anhydride in A2 is 1:2-3.

[0025] Preferably, the amount of ammonium persulfate in A3 is 1-2% of the mass of the esterified modified starch.

[0026] Preferably, the mass ratio of esterified modified starch, acrylic acid, and sodium styrene sulfonate in A3 is 1:0.20-0.30:0.10-0.15.

[0027] A method for preparing an agricultural self-dispersing multi-component compound herbicide composition includes the following steps:

[0028] S1. Add potassium salt of dicofol, potassium salt of nicosulfuron, potassium salt of benzoyl sulfone, maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, sodium polyacrylate, naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, fatty alcohol sulfonate or fatty alcohol sulfate, and filler to a kneader and dry mix for 10-15 min. After mixing, perform air jet milling to produce solid particles with a particle size of 10-15 μm.

[0029] S2. Add the solid particles from S1 and 8-12 parts of deionized water to a kneader and knead for 20-30 minutes at 20-40℃. Then pour the mixture into a granulator and granulate at 25-45℃ to obtain wet particles with a particle size of 0.4-2.0 mm.

[0030] S3. The wet granules obtained in S2 are then subjected to boiling drying. The inlet air temperature is 60-80℃, and the moisture content of the discharged product is maintained at 0.8-1.5%. The dried granules are collected, sieved, and columnar uniform granules are obtained, which are the finished herbicide products.

[0031] Preferably, the process conditions for airflow pulverization in S1 are: pulverization inlet air temperature of 10-25℃ and pressure of 0.8-1.0MPa.

[0032] Preferably, the mechanism of action of the agricultural auto-dispersible multi-component herbicide composition of the present invention is explained as follows:

[0033] In terms of physical mechanism, this composition achieves "automatic dispersion" upon introduction into water through careful component and process design. The core of the particles is a composite dispersant system, in which a self-made maleic anhydride esterified starch-grafted acrylic acid-styrene sulfonate copolymer serves as the main dispersant. Its unique comb-like structure, with biodegradable starch as the main chain, provides the initial disintegration kinetics for the particles through moderate and rapid swelling upon contact with water. This rapidly disrupts the particle structure and increases the contact area with water. The acrylic acid-styrene sulfonate copolymer side chains grafted onto the main chain possess extremely strong hydrophilicity and charge density. Once in contact with water molecules, they rapidly extend and preferentially adsorb onto the surface of the active ingredient particles exposed during disintegration. These side chains disperse through electrostatic repulsion and steric hindrance. This design provides immediate and powerful stabilization for the microparticles. In this design, the swelling of the starch backbone is the "triggering" and "accelerating" process, while the adsorption and stabilization of the grafted side chains are the "dominant" and "maintaining" processes. The two are closely linked and mutually reinforcing in terms of timing and function: the swelling of the backbone promotes rapid particle disintegration, creating conditions for the rapid adsorption of the side chains; while the strong stabilizing effect of the side chains effectively prevents the re-aggregation of microparticles that may be caused by the swelling of the backbone, ensuring the long-term stability of the suspension. This copolymer successfully combines the disintegration function and the dispersion stabilization function at the molecular scale, achieving a synergistic effect that is superior to the simple combination of a single disintegrant and a single dispersant.

[0034] Meanwhile, the naphthalene sulfonate formaldehyde condensate, sodium lignosulfonate, and sodium polyacrylate in the formula act as auxiliary dispersants, further enhancing the dispersion stability of the system. Fatty alcohol sulfonates or sulfates act as wetting agents, significantly reducing the surface tension of water and allowing the particle surface to be quickly wetted. When the particles come into contact with water, water molecules quickly penetrate into the interior through capillary action, causing the filler, corn starch (which swells after absorbing water), and potassium carbonate (which dissolves rapidly and generates local osmotic pressure) that are present in solid form beforehand to disintegrate rapidly together, generating internal stress. Ultimately, this causes the particles to "automatically" disintegrate from the outside to the inside into countless active microparticles with uniform particle size that are stably wrapped by the dispersant, forming a stable suspension that ensures that the active ingredients are evenly distributed in the water without rapid sedimentation.

[0035] In terms of chemical mechanism of action, this composition achieves the complementary advantages of three highly effective herbicides. Specifically, dicamba potassium salt is a benzoic acid hormone-type herbicide that, after being absorbed by weeds, disrupts their growth hormone balance, leading to plant malformation, vascular bundle rupture, and death. Nicosulfuron potassium salt is a sulfonamide acetolactate synthase (ALS) inhibitor that inhibits the activity of ALS enzymes in weeds, blocking the biosynthesis of branched-chain amino acids (valine, leucine, and isoleucine), thereby hindering protein synthesis and cell division. Benzopyrazol potassium salt is a benzoylpyrazole 4-hydroxyphenylpyruvate dioxygenase (HP) enzyme. PD inhibitors suppress plastoquinone biosynthesis, leading to whitening and necrosis of weed meristems. Combining these three ingredients can effectively control both broadleaf weeds (such as field bindweed and purslane targeted by dicamba) and grass weeds (such as crabgrass and foxtail grass targeted by nicosulfuron). More importantly, by superimposing different, highly targeted weed-controlling mechanisms, the probability of simultaneous development of resistance in weed populations is significantly reduced, thereby delaying the development of resistance and achieving efficient and long-lasting control of multiple resistant weed populations.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] 1. This invention combines three herbicides with complementary mechanisms of action: dicamba potassium salt, nicosulfuron potassium salt, and benzoxazine potassium salt. Dicamba is a hormone-type herbicide that causes plant malformation and death by interfering with the balance of growth hormones in weeds. Nicosulfuron is an acetolactate synthase (ALS) inhibitor that blocks weed growth by inhibiting the synthesis of branched-chain amino acids (valine, leucine, and isoleucine). Benzoxazine is a benzoylpyrazole 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor that causes whitening and necrosis of weed meristems by inhibiting the biosynthesis of plastoquinone. The combination of these three herbicides can effectively control both broadleaf weeds and grass weeds.

[0038] 2. This invention achieves rapid and automatic disintegration and dispersion of particles upon contact with water by constructing a multi-layered composite dispersant system. Maleic anhydride esterified starch grafted with acrylate-styrene sulfonate copolymer serves as the main dispersant. Its unique comb-like structure, with biodegradable starch as the main chain and grafted polymer side chains containing carboxyl and sulfonate groups, allows it to rapidly extend in water. Through the combined effects of electrostatic repulsion and steric hindrance, it is efficiently and stably pulverized into active particles of 10-15 μm. Simultaneously, naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, and sodium polyacrylate serve as auxiliary dispersants to further enhance the system's stability. Fatty alcohol sulfonates or sulfates act as wetting agents to reduce the surface tension of water, enabling rapid wetting of the particle surface.

[0039] 3. In this invention, the three active ingredients are pre-potassium salted. The potassium salt granules are prepared by mixing dicamba, nicosulfuron, benzoxazine, and potassium carbonate with water, stirring, extrusion granulation, and boiling drying. This process not only improves the water solubility of each active ingredient, making it easier to disperse in water, but also ensures the uniform distribution and content stability of the active ingredients in the final product through pre-granulation. Attached Figure Description

[0040] Figure 1 This is a photograph of the herbicide composition of Example 2 of the present invention. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0042] Example 1: An agricultural auto-dispersible multi-component herbicide composition, comprising the following components:

[0043] 10 parts of dicofol potassium salt, 10 parts of nicosulfuron potassium salt, 20 parts of benzoyl sulfone potassium salt, 15 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfonate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0044] The preparation method of potassium dicamba is as follows: Mix 100 parts of dicamba and 30 parts of potassium carbonate for 10 minutes, add 15 parts of deionized water, stir for 15 minutes, granulate by extrusion granulation into particles with a diameter of 0.4 mm, and then perform boiling drying with the inlet air temperature at 60℃, keeping the moisture content of the output product at 1.5%, collect the dried particles, and obtain potassium dicamba.

[0045] The preparation method of nicosulfuron potassium salt is as follows: 100 parts of nicosulfuron and 16 parts of potassium carbonate are mixed for 10 minutes, 15 parts of deionized water are added, and the mixture is stirred for 15 minutes. The mixture is then granulated into particles with a diameter of 0.4 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 60℃. The moisture content of the output product is maintained at 1.5%. The dried particles are collected to obtain nicosulfuron potassium salt.

[0046] The preparation method of benzoxazine potassium salt is as follows: 100 parts of benzoxazine and 20 parts of potassium carbonate are mixed for 10 minutes, 15 parts of deionized water are added, and the mixture is stirred for 15 minutes. The mixture is then granulated into particles with a diameter of 0.4 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 60℃. The moisture content of the output product is kept at 1.5%. The dried particles are collected to obtain benzoxazine potassium salt.

[0047] The preparation method of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate sodium copolymer is as follows:

[0048] A1. Take 100g of dried corn starch (weight-average molecular weight 1×10⁻⁶). 6 Da (amylose with a mass fraction of 24%) was dispersed in 400 mL of deionized water, 2 g of anhydrous sodium carbonate was added, and the mixture was stirred at 200 rpm for 25 min at room temperature. The pH was then adjusted to neutral with 8% dilute hydrochloric acid, filtered, washed twice with deionized water, and the filter cake was vacuum dried at 45 °C for 12 h to obtain pretreated corn starch.

[0049] A2. Take 100g of the pretreated corn starch obtained in A1, disperse it in 300mL of anhydrous DMF, add 200g of maleic anhydride, heat to 60℃ under nitrogen protection, stir at 200rpm for 5h, cool to room temperature after the reaction, filter, wash the solid twice with anhydrous ethanol and twice with deionized water, and then dry it under vacuum at 45℃ for 12h. The dried product is pulverized and passed through a 100-mesh sieve to obtain esterified modified starch.

[0050] A3. Take 100g of the esterified modified starch obtained in A2, disperse it in 900mL of deionized water, stir at 55℃ and 200rpm for 25min, adjust the pH to 6.5 with 8% sodium hydroxide aqueous solution, heat to 75℃ under nitrogen protection, add 1g of ammonium persulfate dissolved in 100mL of deionized water to prepare an ammonium persulfate aqueous solution, stir for 15min, and then slowly and evenly add 20g of acrylic acid and 10g of sodium styrene sulfonate dissolved in 100mL of deionized water in a mixed monomer aqueous solution over 2h. After the addition is complete, keep the temperature at 75℃ and continue the reaction for 2h. After the reaction is completed, cool to room temperature, let stand in anhydrous ethanol for 1h, and a white precipitate will precipitate. Filter, wash the filter cake twice with 70% anhydrous ethanol aqueous solution, and then wash once with anhydrous ethanol. Collect the solid, vacuum dry at 45℃ for 12h, pulverize and pass through a 150-mesh sieve to obtain maleic anhydride esterified starch grafted with acrylic acid-sodium styrene sulfonate copolymer.

[0051] A method for preparing an agricultural self-dispersing multi-component compound herbicide composition includes the following steps:

[0052] S1. Add potassium salt of dicofol, potassium salt of nicosulfuron, potassium salt of benzoyl sulfone, maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, sodium polyacrylate, naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, fatty alcohol sulfonate, potassium carbonate, and corn starch to a kneader and dry mix for 10 minutes. After mixing, perform air jet milling with an air inlet temperature of 10℃ and a pressure of 0.8MPa to produce solid particles with a particle size of 10μm.

[0053] S2. Add the solid particles obtained in S1 and 12 parts of deionized water to a kneader and knead for 20 minutes at 20°C. Then pour the mixture into a granulator and granulate at 25°C to obtain wet particles with a particle size of 1.0 mm.

[0054] S3. The wet granules obtained in S2 are subjected to boiling drying with an inlet air temperature of 60℃. The moisture content of the discharged product is maintained at 0.8%. The dried granules are collected, sieved, and columnar uniform granules are obtained, which are the finished herbicide products.

[0055] Example 2: An agricultural self-dispersing multi-component herbicide composition, comprising the following components:

[0056] 20 parts of dicofol potassium salt, 8 parts of nicosulfuron potassium salt, 15 parts of benzoyl sulfone potassium salt, 15 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfonate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0057] The preparation method of potassium dicamba is as follows: Mix 100 parts of dicamba and 35 parts of potassium carbonate for 12 minutes, add 18 parts of deionized water, stir for 18 minutes, granulate by extrusion granulation into particles with a diameter of 1.5 mm, and then perform boiling drying with the inlet air temperature at 70℃, keeping the moisture content of the output product at 3.0%, collect the dried particles to obtain potassium dicamba.

[0058] The preparation method of nicosulfuron potassium salt is as follows: 100 parts of nicosulfuron and 18 parts of potassium carbonate are mixed for 12 minutes, 18 parts of deionized water are added, and the mixture is stirred for 18 minutes. The mixture is then granulated into particles with a diameter of 1.5 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 70℃. The moisture content of the output product is maintained at 3.0%. The dried particles are collected to obtain nicosulfuron potassium salt.

[0059] The preparation method of benzoxazine potassium salt is as follows: 100 parts of benzoxazine and 22 parts of potassium carbonate are mixed for 12 minutes, 18 parts of deionized water are added, and the mixture is stirred for 18 minutes. The mixture is then granulated into particles with a diameter of 1.5 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 70℃. The moisture content of the output product is maintained at 3.0%. The dried particles are collected to obtain benzoxazine potassium salt.

[0060] The preparation method of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate sodium copolymer is as follows:

[0061] A1. Take 100g of dried corn starch (weight average molecular weight 5×10⁻⁶). 6Da (amylose, amylose content 26%) was dispersed in 300 mL of deionized water, 3.5 g of anhydrous sodium carbonate was added, and the mixture was stirred at 250 rpm for 30 min at room temperature. The pH was then adjusted to neutral with 9% dilute hydrochloric acid, filtered, washed three times with deionized water, and the filter cake was vacuum dried at 50 °C for 18 h to obtain pretreated corn starch.

[0062] A2. Take 100g of the pretreated corn starch obtained in A1, disperse it in 400mL of anhydrous DMF, add 250g of maleic anhydride, heat to 65℃ under nitrogen protection, stir at 250rpm for 5.5h, cool to room temperature after the reaction, filter, wash the solid three times with anhydrous ethanol and three times with deionized water, and then dry it under vacuum at 50℃ for 18h. The dried product is pulverized and passed through a 120-mesh sieve to obtain esterified modified starch.

[0063] A3. Take 100g of the esterified modified starch obtained in A2, disperse it in 700mL of deionized water, stir at 60℃ and 300rpm for 30min, adjust the pH to 7.0 with 9% sodium hydroxide aqueous solution, heat to 80℃ under nitrogen protection, add 1.5g of ammonium persulfate dissolved in 100mL of deionized water to prepare ammonium persulfate aqueous solution, stir for 18min, and then slowly and evenly add 25g of acrylic acid and 12.5g of sodium styrene sulfonate dissolved in 112.5mL of deionized water mixed monomer aqueous solution over 2.5h. After the addition is complete, keep the temperature at 80℃ and continue the reaction for 2.5h. After the reaction is completed, cool to room temperature, let stand in anhydrous ethanol for 1.5h, a white precipitate precipitates, filter, wash the filter cake 3 times with 75% anhydrous ethanol aqueous solution, and then wash twice with anhydrous ethanol, collect the solid, vacuum dry at 50℃ for 18h, pulverize and pass through an 180-mesh sieve to obtain maleic anhydride esterified starch grafted with acrylic acid-sodium styrene sulfonate copolymer.

[0064] A method for preparing an agricultural self-dispersing multi-component compound herbicide composition includes the following steps:

[0065] S1. Add potassium salt of dicofol, potassium salt of nicosulfuron, potassium salt of benzoyl sulfone, maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, sodium polyacrylate, naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, fatty alcohol sulfonate, potassium carbonate, and corn starch to a kneader and dry mix for 12 minutes. After mixing, perform air jet milling with an air inlet temperature of 20°C and a pressure of 0.9 MPa to produce solid particles with a particle size of 12 μm.

[0066] S2. Add the solid particles from S1 and 10 parts of deionized water to a kneader and knead at 30°C for 25 minutes. Then pour the mixture into a granulator and granulate at 35°C to obtain wet particles with a particle size of 0.4 mm.

[0067] S3. The wet granules obtained in S2 are subjected to boiling drying with an inlet air temperature of 70℃. The moisture content of the discharged product is kept at 1.0%. The dried granules are collected, sieved, and columnar uniform granules are obtained, which are the finished herbicide products.

[0068] Example 3: An agricultural self-dispersing multi-component herbicide composition, comprising the following components:

[0069] 30 parts of dicofol potassium salt, 5 parts of nicosulfuron potassium salt, 10 parts of benzoyl sulfone potassium salt, 15 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfonate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0070] The preparation method of potassium dicamba is as follows: Mix 100 parts of dicamba and 40 parts of potassium carbonate for 15 minutes, add 20 parts of deionized water, stir for 20 minutes, granulate by extrusion granulation into particles with a diameter of 3.0 mm, and then perform boiling drying with the inlet air temperature at 80℃ and the moisture content of the output product maintained at 5.0%. Collect the dried particles to obtain potassium dicamba.

[0071] The preparation method of nicosulfuron potassium salt is as follows: 100 parts of nicosulfuron and 20 parts of potassium carbonate are mixed for 15 minutes, 20 parts of deionized water are added, and the mixture is stirred for 20 minutes. The mixture is then granulated into particles with a diameter of 3.0 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 80℃. The moisture content of the output product is maintained at 5.0%. The dried particles are collected to obtain nicosulfuron potassium salt.

[0072] The preparation method of benzoxazine potassium salt is as follows: 100 parts of benzoxazine and 25 parts of potassium carbonate are mixed for 15 minutes, 20 parts of deionized water are added, and the mixture is stirred for 20 minutes. The mixture is then granulated into particles with a diameter of 3.0 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 80℃. The moisture content of the output product is maintained at 5.0%. The dried particles are collected to obtain benzoxazine potassium salt.

[0073] The preparation method of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate sodium copolymer is as follows:

[0074] A1. Take 100g of dried corn starch (weight-average molecular weight 1×10⁻⁶). 7 Da (amylose with a mass fraction of 28%) was dispersed in 233 mL of deionized water, 5 g of anhydrous sodium carbonate was added, and the mixture was stirred at 300 rpm for 35 min at room temperature. The pH was then adjusted to neutral with 10% dilute hydrochloric acid, filtered, washed three times with deionized water, and the filter cake was vacuum dried at 55 °C for 24 h to obtain pretreated corn starch.

[0075] A2. Take 100g of the pretreated corn starch obtained in A1, disperse it in 500mL of anhydrous DMF, add 300g of maleic anhydride, heat to 70℃ under nitrogen protection, stir at 300rpm for 6h, cool to room temperature after the reaction, filter, wash the solid three times with anhydrous ethanol and three times with deionized water, and then dry it under vacuum at 55℃ for 24h. The dried product is pulverized and passed through a 150-mesh sieve to obtain esterified modified starch.

[0076] A3. Take 100g of the esterified modified starch obtained in A2, disperse it in 567mL of deionized water, stir at 65℃ and 400rpm for 35min, adjust the pH to 7.0 with 10% sodium hydroxide aqueous solution, heat to 85℃ under nitrogen protection, add 2g of ammonium persulfate dissolved in 100mL of deionized water to prepare an ammonium persulfate aqueous solution, stir for 20min, and then slowly and evenly add 30g of acrylic acid and 15g of sodium styrene sulfonate dissolved in 150mL of deionized water in a mixed monomer aqueous solution over 3h. After the addition is complete, keep the temperature at 85℃ and continue the reaction for 3h. After the reaction is completed, cool to room temperature, let stand in anhydrous ethanol for 2h, and a white precipitate will precipitate. Filter, wash the filter cake 3 times with 80% anhydrous ethanol aqueous solution, and then wash it 2 times with anhydrous ethanol. Collect the solid, vacuum dry at 55℃ for 24h, pulverize and pass through a 200-mesh sieve to obtain maleic anhydride esterified starch grafted with acrylic acid-sodium styrene sulfonate copolymer.

[0077] A method for preparing an agricultural self-dispersing multi-component compound herbicide composition includes the following steps:

[0078] S1. Add potassium salt of dicofol, potassium salt of nicosulfuron, potassium salt of benzoyl sulfone, maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, sodium polyacrylate, naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, fatty alcohol sulfonate, potassium carbonate, and corn starch to a kneader and dry mix for 15 minutes. After mixing, perform air jet milling with an air inlet temperature of 25°C and a pressure of 1.0 MPa to produce solid particles with a particle size of 15 μm.

[0079] S2. Add the solid particles obtained in S1 and 8 parts of deionized water to a kneader and knead at 40°C for 30 minutes. Then pour the mixture into a granulator and granulate at 45°C to obtain wet particles with a particle size of 2.0 mm.

[0080] S3. The wet granules obtained in S2 are subjected to boiling drying with an inlet air temperature of 80℃. The moisture content of the discharged product is kept at 1.5%. The dried granules are collected, sieved, and columnar uniform granules are obtained, which are the finished herbicide products.

[0081] Example 4: An agricultural self-dispersing multi-component herbicide composition, comprising the following components:

[0082] 40 parts of dicofol potassium salt, 3 parts of nicosulfuron potassium salt, 5 parts of benzoyl sulfone potassium salt, 15 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfonate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0083] The preparation methods of potassium salt of dicamba, potassium salt of nicosulfuron, potassium salt of benzoyl permethrin, and maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, as well as the preparation method of an agricultural auto-dispersible multi-component compound herbicide composition, are the same as in Example 2.

[0084] Example 5: An agricultural auto-dispersible multi-component herbicide composition, comprising the following components:

[0085] 50 parts of dicofol potassium salt, 1 part of nicosulfuron potassium salt, 1 part of benzoyl sulfone potassium salt, 15 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfonate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0086] The preparation methods of potassium salt of dicamba, potassium salt of nicosulfuron, potassium salt of benzoyl permethrin, and maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, as well as the preparation method of an agricultural auto-dispersible multi-component compound herbicide composition, are the same as in Example 2.

[0087] Example 6: An agricultural self-dispersing multi-component herbicide composition, comprising the following components:

[0088] 20 parts of dicofol potassium salt, 8 parts of nicosulfuron potassium salt, 15 parts of benzoyl sulfone potassium salt, 15 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0089] The preparation methods of potassium salt of dicamba, potassium salt of nicosulfuron, potassium salt of benzoyl permethrin, and maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, as well as the preparation method of an agricultural auto-dispersible multi-component compound herbicide composition, are the same as in Example 2.

[0090] Example 7: An agricultural auto-dispersible multi-component herbicide composition, comprising the following components:

[0091] 20 parts of potassium dicofol, 8 parts of potassium nicosulfuron, 15 parts of potassium benzoate, 20 parts of maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, 5 parts of sodium polyacrylate, 5 parts of naphthalene sulfonate formaldehyde condensate, 5 parts of sodium lignin sulfonate, 3 parts of fatty alcohol sulfonate, 5 parts of potassium carbonate, and corn starch to make up to 100 parts.

[0092] The preparation methods of potassium salt of dicamba, potassium salt of nicosulfuron, potassium salt of benzoyl permethrin, and maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, as well as the preparation method of an agricultural auto-dispersible multi-component compound herbicide composition, are the same as in Example 2.

[0093] Comparative Example 1: Compared with Example 2, no potassium dicamba salt was added in Comparative Example 1, and the amount of corn starch was increased accordingly to make up to 100 parts. Other components and preparation methods (without the need for potassium dicamba salt preparation) were the same as in Example 2.

[0094] Comparative Example 2: Compared with Example 2, no nicosulfuron potassium salt was added in Comparative Example 2, and the amount of corn starch was increased accordingly to make up to 100 parts. Other components and preparation methods (preparation without nicosulfuron potassium salt) were the same as in Example 2.

[0095] Comparative Example 3: Compared with Example 2, Comparative Example 3 did not add benzoxazine potassium salt, and the amount of corn starch was increased accordingly to make up to 100 parts. Other components and preparation methods (without the need for benzoxazine potassium salt preparation) were the same as in Example 2.

[0096] Comparative Example 4: Compared with Example 2, Comparative Example 4 did not add maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer, and the amount of corn starch was increased accordingly to make up to 100 parts. Other components and preparation methods (preparation without maleic anhydride esterified starch grafted with acrylic acid-styrene sulfonate copolymer) were the same as in Example 2.

[0097] Comparative Example 5: Compared with Example 2, in Comparative Example 5, dicamba potassium salt was replaced with an equal amount of dicamba, nicosulfuron potassium salt was replaced with an equal amount of nicosulfuron, and benzoxazine potassium salt was replaced with an equal amount of benzoxazine. The amount of corn starch was increased accordingly to make up 100 parts. Other components and preparation methods (no need to prepare dicamba potassium salt, nicosulfuron potassium salt, and benzoxazine potassium salt) were the same as in Example 2.

[0098] Table 1. Formulation composition of the examples and comparative examples (unit: parts by weight)

[0099]

[0100] Performance testing:

[0101] 1. Dispersibility test: The test was conducted in accordance with GB / T 32775-2016 "Determination of Dispersibility of Pesticides". 98 mL of deionized water was added to a stoppered graduated cylinder. 2 g of the samples from Examples 1-7 and Comparative Examples 1-5 were weighed and added to the graduated cylinder. The amount of precipitation at 30 min and 60 min was recorded respectively.

[0102] 2. Suspension rate test: The test was conducted in accordance with GB / T 14825-2023 "Determination of Suspension Rate of Pesticides". For the initial suspension rate test, the samples of Examples 1-7 and Comparative Examples 1-5 were diluted with water to the specified concentration. After standing in a graduated cylinder for a certain period of time, the content of active ingredients or the mass of solid residue in the bottom tenth of the suspension was measured, and the suspension rate was calculated. Suspension rate (%) = 10 / 9 × (1 - mass of active ingredients in the bottom 25mL suspension / total mass of active ingredients in the sample in the graduated cylinder) × 100%; For the heat storage suspension rate test, in accordance with GB / T 19136-2021 "Determination of Heat Storage Stability of Pesticides", the samples of Examples 1-7 and Comparative Examples 1-5 were placed in a constant temperature chamber at 54℃ for 14 days and the suspension rate after heat storage was measured.

[0103] 3. Disintegration test: Add 0.5g of sample particles to a 100ml stoppered graduated cylinder containing 90ml of deionized water at 25℃ until the sample completely disintegrates in the water. Record the time, which is the disintegration time. The initial disintegration time is measured directly on the product immediately after production and packaging. The disintegration time after heat storage at 54℃ is measured according to GB / T 19136-2021 "Test Method for Heat Storage Stability of Pesticides". The samples of Examples 1-7 and Comparative Examples 1-5 are placed in a constant temperature chamber at 54℃ for 14 days and the disintegration time after heat storage is measured.

[0104] 4. Safety test (plant height inhibition rate) of maize: The safety of the herbicide composition to maize was evaluated by pot experiment. Under greenhouse conditions, conventional maize varieties were selected and the tested herbicide composition was sprayed at the recommended field dosage when the maize was at the 3-5 leaf stage. Water spraying was used as a blank control. The growth of maize was observed regularly after application. The plant height of maize was investigated at certain days after application (e.g., 14d, 21d, 28d). The plant height inhibition rate was calculated by the following formula: Plant height inhibition rate (%) = (control plant height - treatment plant height) / control plant height × 100%.

[0105] 5. Control efficacy test for grassy and broadleaf weeds: The test was conducted according to GB / T 17980 "Field Efficacy Test Guidelines for Pesticides Part 42: Herbicides for Controlling Weeds in Corn Fields". The main target weeds were barnyardgrass (Digitaria sanguinalis) and broadleaf weed (Portulaca oleracea). A water control, a conventional herbicide control, and a treatment area for the composition of this invention were set up, with each plot measuring 20 m². 2The treatment was repeated four times. The application methods were soil sealing or foliar spraying. Weed surveys were conducted 10 days and 20 days after application, and the number of surviving grass weeds and broadleaf weeds was recorded. The control effect was mainly evaluated by the control efficacy per plant. Control efficacy per plant (%) = (number of weeds in the control area - number of weeds in the treatment area) / number of weeds in the control area × 100%; control efficacy per fresh weight (%) = (fresh weight of weeds in the control area - fresh weight of weeds in the treatment area) / fresh weight of weeds in the control area × 100%.

[0106] Table 2. Physical performance test data of the examples and comparative examples

[0107]

[0108] As can be seen from the data in Table 2:

[0109] Examples 1-7 of this invention all exhibit excellent autodispersibility and formulation stability. The sedimentation amounts at 30 min and 60 min are both less than 0.5 mL, indicating good suspension stability and easy redispersibility after storage. In addition, the initial suspension rates of Examples 1-7 are all higher than 92%, and even after 14 days of heat storage at 54°C, the suspension rate remains above 90%, indicating good heat storage stability. Disintegration performance is a key indicator for measuring the "autodispersibility" characteristic. The initial disintegration time of Examples 1-7 is between 30-45 s, which is slightly prolonged after heat storage, but still within 60 s, achieving the goal of rapid disintegration upon contact with water. Among them, Examples 2 and 7 have the best overall physical properties, the least sedimentation, the fastest initial disintegration (30-32 s), and the highest initial suspension rate (92.9%).

[0110] In contrast, the physical properties of Comparative Examples 1-3 (which lacked one of the following: potassium salts: dicamba, nicosulfuron, and benzoxazine) showed a significant decline, with precipitation increasing to 1.0-2.0 mL, disintegration time exceeding 65 s, and suspension rate decreasing to around 84%. This indicates that the absence of any active ingredient has a certain negative impact on physical properties, but it is not a decisive factor. The performance of Comparative Example 4 (which lacked the core component maleic anhydride esterified starch grafted with acrylic acid-sodium styrene sulfonate copolymer) deteriorated the most severely, with precipitation reaching 2.5-4.2 mL, disintegration time exceeding 95 s (145 s after heat storage), and suspension rate of only about 80%. This demonstrates that the self-made graft copolymer, as the main dispersant, is the core component for constructing a multi-level composite dispersion system, achieving rapid autodisintegration, and high suspension stability. The physical properties of Comparative Example 5 (which used three herbicide technicals without potassium salt treatment) were also significantly worse than those of all Examples 1-3, indicating that pre-potassium salt treatment can effectively improve the water solubility of the active ingredient and its dispersion uniformity in the formulation system.

[0111] Table 3. Test data on maize plant height inhibition rate and weed control effect in the examples and comparative cases.

[0112]

[0113] As can be seen from the data in Table 3:

[0114] Examples 1-7 showed extremely low plant height inhibition rates in maize (between 0.8% and 2.8% at 28 days), indicating that the herbicide of the present invention is highly safe for maize crops. In terms of weed control efficacy, Examples 1-7 generally achieved plant control efficacy and fresh weight control efficacy against gramineous weeds (such as crabgrass) and broadleaf weeds (such as purslane) above 87% 20 days after application, with most between 90% and 94%, demonstrating highly efficient weed control characteristics. Among them, Examples 2, 6, and 7, with relatively balanced active ingredient ratios, showed the best overall control effect.

[0115] The herbicidal effects of Comparative Examples 1-3 (each lacking one active ingredient) were significantly lower than those of Examples 1-7, indicating that the combination of three herbicides with different mechanisms of action—dicamba, nicosulfuron, and benzoxazine—had a significant synergistic effect, effectively controlling both grasses and broadleaf weeds simultaneously. Comparative Example 4 (lacking the main dispersant) showed a significantly higher plant height inhibition rate (reaching 6.8% after 28 days), exhibiting the worst control efficacy. This was due to poor dispersibility, leading to uneven distribution of the herbicide concentration. Some areas had excessively high concentrations, causing phytotoxicity, while others had excessively low concentrations, significantly reducing the actual herbicidal effect. The herbicidal effect of Comparative Example 5 (using the technical grade herbicide) was comparable to that of Comparative Examples 1-3, but its safety to corn (plant height inhibition rate of 5.0%) was significantly worse than that of Examples 1-7 using potassium salt. This confirms that potassium salt treatment not only improves physical properties but also enhances crop safety.

[0116] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An agricultural auto-dispersible multi-component herbicide composition, characterized in that, It is made from the following components by weight: 10-50 parts of dicofol potassium salt, 1-10 parts of nicosulfuron potassium salt, 1-20 parts of benzoyl sulfone potassium salt, 15-20 parts of maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, 3-10 parts of sodium polyacrylate, 3-10 parts of naphthalene sulfonate formaldehyde condensate, 3-10 parts of sodium lignin sulfonate, 2-5 parts of fatty alcohol sulfonate or fatty alcohol sulfate, and 5-30 parts of filler.

2. The agricultural auto-dispersible multi-component herbicide composition according to claim 1, characterized in that, The preparation method of the potassium salt of dicamba is as follows: 100 parts of dicamba and 30-40 parts of potassium carbonate are mixed for 10-15 minutes, 15-20 parts of deionized water are added, and the mixture is stirred for 15-20 minutes. The mixture is then granulated into particles with a diameter of 0.4-3.0 mm by extrusion granulation, and then subjected to boiling drying with an inlet air temperature of 60-80℃. The moisture content of the output product is maintained at 1.5-5%. The dried particles are collected to obtain potassium salt of dicamba.

3. The agricultural auto-dispersible multi-component herbicide composition according to claim 1, characterized in that, The preparation method of the nicosulfuron potassium salt is as follows: 100 parts of nicosulfuron and 16-20 parts of potassium carbonate are mixed for 10-15 minutes, 15-20 parts of deionized water are added, and the mixture is stirred for 15-20 minutes. The mixture is then granulated into particles with a diameter of 0.4-3.0 mm by extrusion granulation, followed by boiling drying with an inlet air temperature of 60-80℃. The moisture content of the output product is maintained at 1.5-5%. The dried particles are collected to obtain nicosulfuron potassium salt.

4. The agricultural auto-dispersible multi-component herbicide composition according to claim 1, characterized in that, The preparation method of the benzoxazine potassium salt is as follows: 100 parts of benzoxazine and 20-25 parts of potassium carbonate are mixed for 10-15 minutes, 15-20 parts of deionized water are added, and the mixture is stirred for 15-20 minutes. The mixture is then granulated into particles with a diameter of 0.4-3.0 mm by extrusion granulation, followed by boiling drying with an inlet air temperature of 60-80℃. The moisture content of the output product is maintained at 1.5-5%. The dried particles are collected to obtain benzoxazine potassium salt.

5. The agricultural auto-dispersible multi-component herbicide composition according to claim 1, characterized in that, The filler is a mixture of corn starch and potassium carbonate in a mass ratio of 2-5:

1.

6. The agricultural auto-dispersible multi-component herbicide composition according to claim 1, characterized in that, The preparation method of the maleic anhydride esterified starch grafted with acrylic acid-sodium styrene sulfonate copolymer is as follows: A1. Disperse the dried corn starch in deionized water to prepare a 20-30 wt% starch suspension. Add anhydrous sodium carbonate and stir at 200-300 rpm for 25-35 min at room temperature. Adjust the pH to neutral with 8-10% dilute hydrochloric acid, filter, wash 2-3 times with deionized water, and vacuum dry at 45-55℃ for 12-24 h to obtain pretreated corn starch. A2. Disperse the pretreated corn starch obtained in A1 in anhydrous N,N-dimethylformamide, add maleic anhydride, and under nitrogen protection, heat to 60-70℃ and stir at 200-300 rpm for 5-6 hours. After the reaction is completed, cool to room temperature, filter, and wash the obtained solid with anhydrous ethanol 2-3 times and deionized water 2-3 times in sequence. Then, vacuum dry at 45-55℃ for 12-24 hours, pulverize and pass through a 100-150 mesh sieve to obtain esterified modified starch. A3. Disperse the esterified modified starch obtained in A2 in deionized water to prepare a 10-15 wt% esterified modified starch suspension. Stir at 55-65℃ and 200-400 rpm for 25-35 min. Adjust the pH of the esterified modified starch aqueous solution to 6.5-7.0 with 8-10% sodium hydroxide aqueous solution. Under nitrogen protection, raise the temperature to 75-85℃, add 1-2 wt% ammonium persulfate aqueous solution, and stir for 15-20 min. Then, slowly and uniformly add acrylic acid and styrene sulfonic acid over 2-3 h. A 20-30 wt% aqueous solution of mixed monomers composed of sodium was added dropwise. After the reaction was completed, the mixture was kept at 75-85℃ for 2-3 hours. After the reaction was completed, the mixture was cooled to room temperature and allowed to stand in anhydrous ethanol for 1-2 hours. A white precipitate was formed. The precipitate was filtered, and the resulting filter cake was washed 2-3 times with 70-80% anhydrous ethanol aqueous solution, and then washed 1-2 times with anhydrous ethanol. The solid was collected and vacuum dried at 45-55℃ for 12-24 hours. After pulverizing, the solid was passed through a 150-200 mesh sieve to obtain maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate sodium copolymer.

7. The agricultural auto-dispersible multi-component herbicide composition according to claim 6, characterized in that, The weight-average molecular weight of the corn starch in A1 is 1×10⁻⁶. 6 -1×10 7 Da, the mass fraction of amylose is 24-28%; the amount of anhydrous sodium carbonate in A1 is 2-5% of the mass of corn starch.

8. The agricultural auto-dispersible multi-component herbicide composition according to claim 6, characterized in that, The ratio of corn starch to N,N-dimethylformamide in A2 is 1g:3-5ml; the mass ratio of corn starch to maleic anhydride in A2 is 1:2-3; the amount of ammonium persulfate in A3 is 1-2% of the mass of esterified modified starch; the mass ratio of esterified modified starch, acrylic acid, and sodium styrene sulfonate in A3 is 1:0.20-0.30:0.10-0.

15.

9. A method for preparing an agricultural auto-dispersible multi-component compound herbicide composition as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Add potassium salt of dicofol, potassium salt of nicosulfuron, potassium salt of benzoyl sulfone, maleic anhydride esterified starch grafted acrylic acid-styrene sulfonate copolymer, sodium polyacrylate, naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, fatty alcohol sulfonate or fatty alcohol sulfate, and filler to a kneader and dry mix for 10-15 minutes. After mixing, perform air jet milling with an air inlet temperature of 10-25℃ and a pressure of 0.8-1.0MPa to produce solid particles with a particle size of 10-15μm. S2. Add the solid particles from S1 and 8-12 parts of deionized water to a kneader and knead for 20-30 minutes at 20-40℃. Then pour the mixture into a granulator and granulate at 25-45℃ to obtain wet particles with a particle size of 0.4-2.0 mm. S3. The wet granules obtained in S2 are then subjected to boiling drying. The inlet air temperature is 60-80℃, and the moisture content of the discharged product is maintained at 0.8-1.5%. The dried granules are collected, sieved, and columnar uniform granules are obtained, which are the finished herbicide products.

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