A herbicidal composition based on bentazon and its preparation method

Abstract

This invention relates to the field of pesticide technology, specifically to a herbicidal composition based on bentazon and its preparation method. The invention involves compounding bentazon, diflubenzuron, microspheres, functional adjuvants, defoamers, and other adjuvants to prepare a herbicidal composition with good herbicidal effect under low-temperature conditions. The microspheres are prepared from hydrophobically modified lignin, bentazon, sodium octenyl succinate starch, and maltodextrin. The hydrophobically modified lignin has good ultraviolet absorption and photothermal conversion capabilities, increasing the temperature of weed leaf surfaces and thus enhancing the physiological activity of weeds. This allows the herbicidal composition to be effectively absorbed by the weeds and exert its herbicidal effect. Sodium octenyl succinate starch and maltodextrin improve the chemical stability of bentazon, preventing its photodecomposition and demonstrating broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and in particular to a herbicidal composition based on metribuzin and its preparation method. Background Technology

[0002] Bentazon (chemical name: 3-isopropyl-(1H)-benzo-2,1,3-thiadiazin-4-one-2,2-dioxide) is a systemic herbicide developed by the German company Baden in 1968. Also known as bentazon or benzoyl permethrin, it belongs to the heterocyclic class of herbicides and is a selective contact herbicide used for foliar application during the seedling stage of weeds. It works through leaf contact. In dryland applications, it is translocated through the leaves to the chloroplasts, inhibiting photosynthesis. In paddy fields, it is also absorbed through the roots and translocated to the stems and leaves, hindering photosynthesis and water metabolism in weeds, causing physiological dysfunction and death. The active ingredient is detoxified in tolerant crops by metabolizing into less active glycoconjugates, making it safe for crops. Bentazon is decomposed by microorganisms in the soil 8-16 weeks after application. Bentazon is a widely used, low-toxicity herbicide, belonging to the heterocyclic class of selective contact post-emergence herbicides. Seedling stage treatment is suitable for various crops such as rice, wheat, corn, sorghum, soybean, peanut, and pea. It has excellent control effects on broadleaf weeds and sedges, but is not very effective against grass weeds. Bentazon has the advantages of high efficiency, low toxicity, broad spectrum of weed control, no phytotoxicity, and good compatibility with other herbicides.

[0003] my country's annual wheat planting area is 350 million mu (approximately 23.3 million hectares), second only to rice. In recent years, weed infestation in wheat fields has become severe. Dominant weeds include wild oats, jointed goatgrass, wild barnyard grass, Japanese wild barnyard grass, wild oats, annual bluegrass, shepherd's purse, shepherd's purse, and cleavers. These weeds compete with wheat for nutrients and living space; some even act as vectors or overwintering carriers for wheat diseases and pests, making them a significant factor affecting wheat yield and quality. Wheat field weeds directly impact wheat crop yields and are a key factor restricting crop production. Controlling wheat field weeds is an important task for developing wheat production.

[0004] In the existing technology, bentazon is often used in combination with other herbicides for weed control in wheat fields. However, bentazon has poor weed control effect under low temperature conditions, especially when applied to winter wheat fields in December and January, where it has almost no weed control effect. Its weed control performance under low temperature conditions needs to be further improved.

[0005] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop a herbicidal composition based on metribuzin and its preparation method. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a herbicidal composition based on bentazon and its preparation method, so as to solve the problem of poor herbicidal effect of bentazon at low temperatures in the prior art.

[0007] To achieve the above objectives, the present invention provides a herbicidal composition based on metribuzin and a method for preparing the same.

[0008] A herbicidal composition based on bentazon comprises the following raw materials in parts by weight: 17-22 parts of metribuzin; 5-7 parts of diflubenzuron; 9-15 parts of microsphere composition; 3-4.9 parts of functional additives; 2-3 parts of fatty alcohol polyoxyethylene ether; 1-2 parts of silica; 2-3 parts of xanthan gum; 0.5-0.8 parts of sodium benzoate; 2-3 parts of ethylene glycol; 1-2 parts of sodium dodecylbenzenesulfonate; 0.2-0.3 parts of silicone defoamer; 55-68 parts of deionized water; The microsphere composition was prepared from hydrophobically modified lignin, bentazon, sodium octenyl succinate starch and maltodextrin; The hydrophobically modified lignin is prepared from lignin powder, dimethyl sulfate and diglycidyl ether.

[0009] Preferably, the preparation method of the hydrophobically modified lignin is as follows: Step A1. Add lignin powder and dimethyl sulfate to the flask, heat to reflux, then add hydrochloric acid solution and mix well. Wash with deionized water to obtain mixture A. Step A2. Place mixture A in a reactor and add diglycidyl ether and N,N-dimethylbenzylamine. Heat the mixture to react. After the reaction is complete, filter, wash, and dry to obtain hydrophobically modified lignin.

[0010] Preferably, the concentration of the hydrochloric acid solution in step A1 is 2 mol / L; The ratio of lignin powder, dimethyl sulfate, and hydrochloric acid solution is 1 mol: 2.4-2.7 mol: 8-13 mL; The temperature during the heating and reflux process is 72-78℃, and the time is 2-2.5h.

[0011] Preferably, the mass ratio of mixture A, diglycidyl ether, and N,N-dimethylbenzylamine in step A2 is 20-30:6.3-8.5:0.3-0.5; The heating reaction is carried out at a temperature of 92-100℃ for 5-6 hours.

[0012] Preferably, the microsphere composition is prepared by the following method: Step B1. Add bentazon and hydrophobically modified lignin to anhydrous ethanol, heat to 35-40℃ and stir evenly to obtain mixture 1; Step B2. Add sodium octenyl succinate starch and maltodextrin to deionized water, stir evenly at 38-45℃, then add sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. Step B3. Add mixture 1 to mixture 2, heat and stir for 30-50 minutes, then homogenize in a shear mill at 1000-1200 rpm for 2-3 minutes, and then spray dry to obtain the microsphere composition.

[0013] Preferably, the ratio of anhydrous ethanol, bentazon, and hydrophobically modified lignin in step B1 is 45-60 mL: 0.4-0.75 g: 0.53-0.8 g.

[0014] Preferably, the ratio of sodium octenyl succinate starch, maltodextrin, deionized water and sucrose fatty acid ester in step B2 is 5.5-10.7g:3-5.8g:30-44mL:0.8-1g.

[0015] Preferably, the volume ratio of mixture 1 to mixture 2 in step B3 is 8-13.7:50-85; The stirring speed during heating is 500-650 rpm and the temperature is 62-68℃.

[0016] Preferably, the functional adjuvant is an immobilized *Cyclocarya paliurus* agent; The method for preparing the immobilized *Gastrodia elata* agent is as follows: Biochar and *Mirabilis* agent were placed in an Erlenmeyer flask and cultured in a constant temperature shaking incubator at 28-32°C and 130-160 r / min for 20-24 hours. After being removed and allowed to stand for 2-3 hours, the mixture was filtered, rinsed with sterile water, and filtered again to obtain immobilized *Mirabilis* agent. The mass ratio of biochar to *Clerodendrum trichotomum* agent is 4-7:7.3-12.5.

[0017] A method for preparing a herbicidal composition based on bentazon includes the following steps: Add bentazon, diflubenzuron, and the microsphere composition to a stainless steel kettle containing deionized water while stirring. After mixing evenly, shear at 5000-6000 rpm for 10-15 min. Then add fatty alcohol polyoxyethylene ether, silica, xanthan gum, sodium benzoate, ethylene glycol, and sodium dodecylbenzene sulfonate. Shear at 3000-3500 rpm for 12-17 min. Finally, add functional additives and silicone defoamer. Shear at 4500-5000 rpm for 8-13 min to obtain the bentazon-based herbicidal composition.

[0018] The beneficial effects of this invention are: This invention provides a herbicidal composition based on bentazon and its preparation method. The invention involves compounding bentazon, diflubenzuron, microspheres, functional adjuvants, defoamers, and other adjuvants to prepare a herbicidal composition with good weed-controlling effect under low-temperature conditions. The microspheres are prepared from hydrophobically modified lignin, bentazon, sodium octenyl succinate starch, and maltodextrin. The hydrophobically modified lignin has excellent UV absorption and photothermal conversion capabilities, increasing the temperature of weed leaf surfaces and thus enhancing the physiological activity of weeds. This allows the herbicidal composition to be effectively absorbed by the weeds and exert its weed-controlling effect. Sodium octenyl succinate starch and maltodextrin improve the chemical stability of bentazon, preventing its photodecomposition. Compared with existing technologies, this invention has broad application prospects. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0020] The sources and properties of some of the raw materials used in this invention are as follows: The *Morphus* strain used in this invention is *Morphus radiata* RUV-113 CGMCC No. 2960, which is disclosed in the invention patent with authorization announcement number "CN101591630B" entitled "A *Morphus radiata* strain and the microbial anti-ultraviolet radiation preparation produced therefrom", and accession number CGMCC No. 2960.

[0021] Example 1: A method for preparing a herbicidal composition based on bentazon, comprising the following steps: S1. Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, add 15g of agar, heat at 50℃ until completely dissolved, filter, and sterilize at 121℃ for 15min to obtain TGY solid culture medium; Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, filter, and sterilize at 121℃ for 15min to obtain TGY liquid culture medium; S2. Inoculate *Gastrococcus pyogenes* onto the surface of TGY solid medium using the spread method and incubate at 30°C for 48 h. Then inoculate it into TGY liquid medium and incubate at 30°C for 24 h using a rotation speed of 180 rpm. Finally, centrifuge at 4000 rpm for 15 min, discard the supernatant, collect the bacterial cells, and prepare a bacterial suspension with sterile water to obtain *Gastrococcus pyogenes* agent. S3. Place 4g of biochar and 7.3g of *Mirabilis* agent in an Erlenmeyer flask and incubate in a constant temperature shaking incubator at 28°C and 130r / min for 20h. After removing the incubator, let it stand for 2h, filter it, rinse it with sterile water, and filter it again to obtain immobilized *Mirabilis* agent. S4. Add 1 mol of lignin powder and 2.4 mol of dimethyl sulfate to a flask, heat under reflux at 72°C for 2 hours, then add 8 mL of 2 mol / L hydrochloric acid solution and mix well. Wash with deionized water to obtain mixture A. S5. Place 20g of mixture A in a reactor, add 6.3g of diglycidyl ether and 0.3g of N,N-dimethylbenzylamine, heat at 92℃ for 5h, filter, wash and dry after the reaction to obtain hydrophobic modified lignin; S6. Add 0.4g of metribuzin and 0.53g of hydrophobic modified lignin to 45mL of anhydrous ethanol, heat to 35℃ and stir evenly to obtain mixture 1; S7. Add 5.5g sodium octenyl succinate starch and 3g maltodextrin to 30mL of deionized water, stir evenly at 38℃, then add 0.8g sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. S8. Add 8 mL of mixture 1 to 50 mL of mixture 2, stir at 500 rpm and 62°C for 30 min, then homogenize in a shear mill at 1000 rpm for 2 min, and then spray dry to obtain the microsphere composition. S9. While stirring, add 17g of bentazon, 5g of diflubenzuron, and 9g of microsphere composition to a stainless steel kettle containing 55g of deionized water. After mixing evenly, shear at 5000r / min for 10min. Then add 2g of fatty alcohol polyoxyethylene ether, 1g of silica, 2g of xanthan gum, 0.5g of sodium benzoate, 2g of ethylene glycol, and 1g of sodium dodecylbenzenesulfonate. Shear at 3000r / min for 12min. Finally, add 3g of functional adjuvant and 0.2g of silicone defoamer. Shear at 4500r / min for 8min to obtain the bentazon-based herbicidal composition.

[0022] Example 2: A method for preparing a herbicidal composition based on bentazon, comprising the following steps: S1. Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, add 15g of agar, heat at 50℃ until completely dissolved, filter, and sterilize at 121℃ for 15min to obtain TGY solid culture medium; Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, filter, and sterilize at 121℃ for 15min to obtain TGY liquid culture medium; S2. Inoculate *Gastrococcus pyogenes* onto the surface of TGY solid medium using the spread method and incubate at 30°C for 55 h. Then inoculate it into TGY liquid medium and incubate at 30°C for 30 h using a rotation speed of 180 rpm. Finally, centrifuge at 5000 rpm for 17 min, discard the supernatant, collect the bacterial cells, and prepare a bacterial suspension with sterile water to obtain *Gastrococcus pyogenes* agent. S3. Place 5g of biochar and 9g of *Cladosporium tumefaciens* agent in an Erlenmeyer flask and incubate in a constant temperature shaking incubator at 30°C and 140r / min for 22h. After removing the incubator, let it stand for 2.5h, filter, rinse with sterile water, and filter again to obtain immobilized *Cladosporium tumefaciens* agent. S4. Add 1 mol of lignin powder and 2.5 mol of dimethyl sulfate to a flask, heat under reflux at 74°C for 2 hours, then add 10 mL of 2 mol / L hydrochloric acid solution and mix well. Wash with deionized water to obtain mixture A. S5. Place 23g of mixture A in a reactor, add 6.8g of diglycidyl ether and 0.37g of N,N-dimethylbenzylamine, heat at 95℃ for 5.5h, filter, wash and dry after the reaction to obtain hydrophobic modified lignin; S6. Add 0.55g of bentazon and 0.62g of hydrophobic modified lignin to 50mL of anhydrous ethanol, heat to 38℃ and stir evenly to obtain mixture 1; S7. Add 7g sodium octenyl succinate starch and 4g maltodextrin to 34mL of deionized water, stir evenly at 40℃, then add 0.9g sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. S8. Add 10.2 mL of mixture 1 to 65 mL of mixture 2, stir at 550 rpm and 64 °C for 35 min, then homogenize in a shear mill at 1100 rpm for 2 min, and then spray dry to obtain the microsphere composition. S9. While stirring, add 19g of bentazon, 6g of diflubenzuron, and 11g of microsphere composition to a stainless steel kettle containing 59g of deionized water. After mixing evenly, shear at 6000r / min for 12min. Then add 2.3g of fatty alcohol polyoxyethylene ether, 1.5g of silica, 2.3g of xanthan gum, 0.6g of sodium benzoate, 2.4g of ethylene glycol, and 1.3g of sodium dodecylbenzenesulfonate. Shear at 3300r / min for 14min. Finally, add 3.7g of functional adjuvant and 0.25g of silicone defoamer. Shear at 4700r / min for 10min to obtain the bentazon-based herbicidal composition.

[0023] Example 3: A method for preparing a herbicidal composition based on bentazon, comprising the following steps: S1. Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, add 15g of agar, heat at 50℃ until completely dissolved, filter, and sterilize at 121℃ for 15min to obtain TGY solid culture medium; Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, filter, and sterilize at 121℃ for 15min to obtain TGY liquid culture medium; S2. Inoculate *Gastrococcus pyogenes* onto the surface of TGY solid medium using the spread method and incubate at 30°C for 68 h. Then inoculate it into TGY liquid medium and incubate at 30°C for 42 h using a rotation speed of 190 rpm. Finally, centrifuge at 480 rpm for 18 min, discard the supernatant, collect the bacterial cells, and prepare a bacterial suspension with sterile water to obtain *Gastrococcus pyogenes* agent. S3. Place 6g of biochar and 11.3g of *Mirabilis* agent in an Erlenmeyer flask and incubate in a constant temperature shaking incubator at 32°C and 150r / min for 23h. After removing the incubator, let it stand for 3h, filter it, rinse it with sterile water, and filter it again to obtain immobilized *Mirabilis* agent. S4. Add 1 mol of lignin powder and 2.6 mol of dimethyl sulfate to a flask, heat under reflux at 76°C for 2.5 h, then add 11 mL of 2 mol / L hydrochloric acid solution and mix well. Wash with deionized water to obtain mixture A. S5. Place 27g of mixture A in a reactor, add 7.5g of diglycidyl ether and 0.42g of N,N-dimethylbenzylamine, heat at 97℃ for 5.5h, filter, wash and dry after the reaction to obtain hydrophobic modified lignin; S6. Add 0.65g of bentazon and 0.7g of hydrophobic modified lignin to 55mL of anhydrous ethanol, heat to 38℃ and stir evenly to obtain mixture 1; S7. Add 9.5g sodium octenyl succinate starch and 5g maltodextrin to 40mL of deionized water, stir evenly at 43℃, then add 0.9g sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. S8. Add 12 mL of mixture 1 to 75 mL of mixture 2, stir at 600 rpm and 66 °C for 50 min, then homogenize in a shear mill at 1200 rpm for 3 min, and then spray dry to obtain the microsphere composition. S9. While stirring, add 20.5g of bentazon, 6.5g of diflubenzuron, and 13g of microsphere composition to a stainless steel kettle containing 62g of deionized water. After mixing evenly, shear at 6000r / min for 14min. Then add 2.7g of fatty alcohol polyoxyethylene ether, 1.8g of silica, 2.7g of xanthan gum, 0.7g of sodium benzoate, 2.6g of ethylene glycol, and 1.8g of sodium dodecylbenzenesulfonate. Shear at 3500r / min for 15min. Finally, add 4.2g of functional adjuvant and 0.28g of silicone defoamer. Shear at 4800r / min for 11min to obtain the bentazon-based herbicidal composition.

[0024] Example 4: A method for preparing a herbicidal composition based on bentazon, comprising the following steps: S1. Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, add 15g of agar, heat at 50℃ until completely dissolved, filter, and sterilize at 121℃ for 15min to obtain TGY solid culture medium; Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, filter, and sterilize at 121℃ for 15min to obtain TGY liquid culture medium; S2. Inoculate *Gastrococcus pyogenes* onto the surface of TGY solid medium using the spread method and incubate at 30°C for 72 h. Then inoculate it into TGY liquid medium and incubate at 30°C for 48 h using a rotation speed of 200 rpm. Finally, centrifuge at 5000 rpm for 20 min, discard the supernatant, collect the bacterial cells, and prepare a bacterial suspension with sterile water to obtain *Gastrococcus pyogenes* agent. S3. Place 7g of biochar and 12.5g of *Bacillus simulans* agent in an Erlenmeyer flask and incubate in a constant temperature shaking incubator at 32°C and 160r / min for 24h. After removing the incubator, let it stand for 3h, filter it, rinse it with sterile water, and filter it again to obtain immobilized *Bacillus simulans* agent. S4. Add 1 mol of lignin powder and 2.7 mol of dimethyl sulfate to a flask, heat under reflux at 78°C for 2.5 h, then add 13 mL of 2 mol / L hydrochloric acid solution and mix well. Wash with deionized water to obtain mixture A. S5. Place 30g of mixture A in a reactor, add 8.5g of diglycidyl ether and 0.5g of N,N-dimethylbenzylamine, heat at 100℃ for 6h, filter, wash and dry after the reaction to obtain hydrophobic modified lignin; S6. Add 0.75g bentazon and 0.8g hydrophobic modified lignin to 60mL of anhydrous ethanol, heat to 40℃ and stir evenly to obtain mixture 1; S7. Add 10.7g sodium octenyl succinate starch and 5.8g maltodextrin to 44mL of deionized water, stir evenly at 45℃, then add 1g sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. S8. Add 13.7 mL of mixture 1 to 85 mL of mixture 2, stir at 650 rpm and 68 °C for 50 min, then homogenize in a shear mill at 1200 rpm for 3 min, and then spray dry to obtain the microsphere composition. S9. While stirring, add 22g of bentazon, 7g of diflubenzuron, and 15g of microsphere composition to a stainless steel kettle containing 68g of deionized water. After mixing evenly, shear at 6000r / min for 15min. Then add 3g of fatty alcohol polyoxyethylene ether, 2g of silica, 3g of xanthan gum, 0.8g of sodium benzoate, 3g of ethylene glycol, and 2g of sodium dodecylbenzenesulfonate. Shear at 3500r / min for 17min. Finally, add 4.9g of functional adjuvant and 0.3g of silicone defoamer. Shear at 5000r / min for 13min to obtain the bentazon-based herbicidal composition.

[0025] Comparative Example 1: Compared with Example 1, this comparative example did not add microsphere composition during the preparation of the herbicidal composition. All other steps and parameters were the same, and will not be repeated here. The final herbicidal composition based on metribuzin was obtained.

[0026] Comparative Example 2: Compared with Example 1, no functional adjuvants were added during the preparation of the herbicidal composition in this comparative example. All other steps and parameters were the same, and will not be repeated here. The final herbicidal composition based on metribuzin was obtained.

[0027] Comparative Example 3: Compared with Example 1, this comparative example did not add hydrophobically modified lignin during the preparation of the microsphere composition. All other steps and parameters were the same, and will not be repeated here. The final herbicidal composition based on metribuzin was obtained.

[0028] Comparative Example 4: S1. Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, add 15g of agar, heat at 50℃ until completely dissolved, filter, and sterilize at 121℃ for 15min to obtain TGY solid culture medium; Weigh 3g of yeast extract, 5g of tryptone, and 1g of glucose, add 1000mL of distilled water, heat at 40℃ until completely dissolved, adjust the pH to 7, filter, and sterilize at 121℃ for 15min to obtain TGY liquid culture medium; S2. Inoculate *Gastrococcus pyogenes* onto the surface of TGY solid medium using the spread method and incubate at 30°C for 48 h. Then inoculate it into TGY liquid medium and incubate at 30°C for 24 h using a rotation speed of 180 rpm. Finally, centrifuge at 4000 rpm for 15 min, discard the supernatant, collect the bacterial cells, and prepare a bacterial suspension with sterile water to obtain *Gastrococcus pyogenes* agent. S3. Place 4g of biochar and 7.3g of *Mirabilis* agent in an Erlenmeyer flask and incubate in a constant temperature shaking incubator at 28°C and 130r / min for 20h. After removing the incubator, let it stand for 2h, filter it, rinse it with sterile water, and filter it again to obtain immobilized *Mirabilis* agent. S4. Add 0.4 g of bentazon to 45 mL of anhydrous ethanol, heat to 35 °C and stir until homogeneous to obtain mixture 1; S5. Add 5.5g sodium octenyl succinate starch, 3g maltodextrin and 0.53g lignin to 30mL of deionized water, stir evenly at 38℃, then add 0.8g sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. S6. Add 8 mL of mixture 1 to 50 mL of mixture 2, stir at 500 rpm and 62°C for 30 min, then homogenize in a shear mill at 1000 rpm for 2 min, and then spray dry to obtain the microsphere composition. S7. While stirring, add 17g of bentazon, 5g of diflubenzuron, and 9g of microsphere composition to a stainless steel kettle containing 55g of deionized water. After mixing evenly, shear at 5000r / min for 10min. Then add 2g of fatty alcohol polyoxyethylene ether, 1g of silica, 2g of xanthan gum, 0.5g of sodium benzoate, 2g of ethylene glycol, and 1g of sodium dodecylbenzenesulfonate. Shear at 3000r / min for 12min. Finally, add 3g of functional adjuvant and 0.2g of silicone defoamer. Shear at 4500r / min for 8min to obtain the bentazon-based herbicidal composition.

[0029] Performance testing: A winter wheat field with average fertility and no other herbicides used before application was selected for the experiment in January. At the time of the experiment, the wheat had 2-3 tillers, and the weeds were at the 3-5 leaf stage. 10 mL of the herbicidal compositions prepared in Examples 1-4 and Comparative Examples 1-4 were diluted with 25 kg of water and divided into 8 groups to treat the winter wheat field. Each treatment was repeated 4 times, and each plot was 40 m². 2 In a randomized block design, on a sunny day, weeds were treated with foliar spraying using a directional spraying method. A blank control group was sprayed with an equal amount of water. Five points were randomly selected from each block, each 0.2m wide. 2 The efficacy of the drug was investigated at 15 days, 30 days and once after application. Methods for calculating drug efficacy: Plant control effect / %= ×100% Table 1. Summary of experimental data from Examples 1-4 and Comparative Examples 1-4 Data Analysis: As shown in Table 1, the herbicidal composition based on bentazon prepared in this invention exhibits better herbicidal effect under low-temperature conditions. This may be because the microsphere composition is prepared from hydrophobically modified lignin, bentazon, sodium octenyl succinate starch, and maltodextrin. The hydrophobically modified lignin has good ultraviolet absorption and photothermal conversion capabilities, increasing the temperature of weed leaves and thus enhancing the physiological activity of weeds. This allows the herbicidal composition to be effectively absorbed by the weeds and exert its herbicidal effect. Furthermore, the hydrophobically modified lignin and bentazon may form a non-covalent bond through π-π stacking interactions, while the hydrophobically modified lignin... Lignin has fewer phenolic active sites, stronger hydrophobicity, and larger surface tension and contact angle, which improves the wettability of bentazon on the leaf surface, facilitating the uniform spread of the herbicidal composition on weeds and improving utilization. Sodium octenyl succinate starch and maltodextrin improve the chemical stability of bentazon, preventing it from being decomposed by light, prolonging its action time, and improving the utilization rate of the herbicidal composition. Furthermore, the functional adjuvant, tebuconazole, can also absorb ultraviolet light and convert it into heat, increasing the temperature of the weed leaf surface. It works synergistically with the microsphere composition to effectively improve the herbicidal rate of bentazon in low-temperature environments. Comparative Example 1, which did not add the microsphere composition, Comparative Example 2, which did not add the functional adjuvant, and Comparative Example 3, which did not add hydrophobically modified lignin during the preparation of the microsphere composition, showed poorer plant control efficacy at low temperatures than Example 1. This may be because the lack of hydrophobically modified lignin and functional adjuvant in the microsphere composition to raise the temperature of the weed leaf surface, resulting in slower weed metabolism and an inability to effectively absorb and conduct the herbicidal composition to its own action site, thus making it difficult to exert a weeding effect. Comparative Example 4, which replaced "hydrophobically modified lignin" in the microsphere composition with "lignin", showed poorer plant control efficacy at low temperatures than Example 1. This may be because hydrophobically modified lignin, compared to lignin, has stronger hydrophobicity, larger surface tension and contact angle, which improves the wettability of metribuzin on the leaf surface, facilitating the uniform spread of the herbicidal composition on the weed leaf surface and thus improving the utilization rate of the herbicidal composition.

[0030] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0031] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A herbicidal composition based on bentazon, characterized in that, Includes the following quantities of raw materials: 17-22 parts of metribuzin; 5-7 parts of diflubenzuron; 9-15 parts of microsphere composition; 3-4.9 parts of functional additives; 2-3 parts of fatty alcohol polyoxyethylene ether; 1-2 parts of silica; 2-3 parts of xanthan gum; 0.5-0.8 parts of sodium benzoate; 2-3 parts of ethylene glycol; 1-2 parts of sodium dodecylbenzenesulfonate; 0.2-0.3 parts of silicone defoamer; 55-68 parts of deionized water; The microsphere composition was prepared from hydrophobically modified lignin, bentazon, sodium octenyl succinate starch and maltodextrin; The hydrophobically modified lignin is prepared from lignin powder, dimethyl sulfate and diglycidyl ether.

2. The herbicidal composition based on bentazon according to claim 1, characterized in that, The preparation method of the hydrophobically modified lignin is as follows: Step A1. Add lignin powder and dimethyl sulfate to the flask, heat to reflux, then add hydrochloric acid solution and mix well. Wash with deionized water to obtain mixture A. Step A2. Place mixture A in a reactor and add diglycidyl ether and N,N-dimethylbenzylamine. Heat the mixture to react. After the reaction is complete, filter, wash, and dry to obtain hydrophobically modified lignin.

3. The herbicidal composition based on bentazon according to claim 2, characterized in that, The concentration of the hydrochloric acid solution mentioned in step A1 is 2 mol / L; The ratio of lignin powder, dimethyl sulfate, and hydrochloric acid solution used is 1 mol: 2.4-2.7 mol: 8-13 mL; The temperature during the heating and reflux process is 72-78℃, and the time is 2-2.5h.

4. The herbicidal composition based on bentazon according to claim 2, characterized in that, The mass ratio of mixture A, diglycidyl ether, and N,N-dimethylbenzylamine in step A2 is 20-30:6.3-8.5:0.3-0.5; The heating reaction is carried out at a temperature of 92-100℃ for 5-6 hours.

5. The herbicidal composition based on bentazon according to claim 1, characterized in that, The microsphere composition is prepared as follows: Step B1. Add bentazon and hydrophobically modified lignin to anhydrous ethanol, heat to 35-40℃ and stir evenly to obtain mixture 1; Step B2. Add sodium octenyl succinate starch and maltodextrin to deionized water, stir evenly at 38-45℃, then add sucrose fatty acid ester, and continue stirring until evenly mixed to obtain mixture 2. Step B3. Add mixture 1 to mixture 2, heat and stir for 30-50 minutes, then homogenize in a shear mill at 1000-1200 rpm for 2-3 minutes, and then spray dry to obtain the microsphere composition.

6. The herbicidal composition based on bentazon according to claim 5, characterized in that, The ratio of anhydrous ethanol, bentazon, and hydrophobically modified lignin used in step B1 is 45-60 mL: 0.4-0.75 g: 0.53-0.8 g.

7. The herbicidal composition based on bentazon according to claim 5, characterized in that, The ratio of sodium octenyl succinate starch, maltodextrin, deionized water and sucrose fatty acid ester used in step B2 is 5.5-10.7g:3-5.8g:30-44mL:0.8-1g.

8. The herbicidal composition based on bentazon according to claim 5, characterized in that, The volume ratio of mixture 1 to mixture 2 in step B3 is 8-13.7:50-85; The stirring speed during heating is 500-650 rpm and the temperature is 62-68℃.

9. The herbicidal composition based on bentazon according to claim 1, characterized in that, The functional adjuvant is an immobilized Coccidia elata agent; The method for preparing the immobilized *Gastrodia elata* agent is as follows: Biochar and *Mirabilis* agent were placed in an Erlenmeyer flask and cultured in a constant temperature shaking incubator at 28-32°C and 130-160 r / min for 20-24 hours. After being removed and allowed to stand for 2-3 hours, the mixture was filtered, rinsed with sterile water, and filtered again to obtain immobilized *Mirabilis* agent. The mass ratio of biochar to *Bacillus simulans* agent is 4-7:7.3-12.

5.

10. The method for preparing the herbicidal composition based on bentazon according to any one of claims 1-9, characterized in that, Includes the following steps: Add bentazon, diflubenzuron, and the microsphere composition to a stainless steel kettle containing deionized water while stirring. After mixing evenly, shear at 5000-6000 rpm for 10-15 min. Then add fatty alcohol polyoxyethylene ether, silica, xanthan gum, sodium benzoate, ethylene glycol, and sodium dodecylbenzene sulfonate. Shear at 3000-3500 rpm for 12-17 min. Finally, add functional additives and silicone defoamer. Shear at 4500-5000 rpm for 8-13 min to obtain the bentazon-based herbicidal composition.

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