Microcapsule slow-release pesticide fertilizer as well as preparation method and application thereof

Abstract

The invention relates to a microcapsule slow-release pesticide fertilizer and a preparation method and application thereof.The microcapsule slow-release pesticide fertilizer comprises a capsule core and a capsule wall, materials of the capsule core comprise water-soluble pesticide and fertilizer, materials of the capsule wall comprise silicon dioxide and calcium carbonate, the mass ratio of the silicon dioxide to the calcium carbonate is 0.7: 1-1.6: 1, the median particle size of the microcapsule slow-release pesticide fertilizer is 0.5-5 micrometers, and the median particle size of the microcapsule slow-release pesticide fertilizer is 0.5-2 micrometers. And the surface potential is-30 mV to-52 mV. The microcapsule slow-release pesticide fertilizer not only has excellent slow-release performance, environmental adaptability and environmental friendliness, but also is high in stability, good in dispersity and long in lasting period, so that the utilization rate of the pesticide fertilizer and the disease resistance of crops can be remarkably improved, meanwhile, an acid-base catalyst is not needed in the preparation process, the process is simple, and the production cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticides, in particular to a microcapsule slow-release fertilizer and a preparation method and application thereof. Background Art

[0002] Integrated pesticide and fertilizer technology is an important development direction in modern agriculture. By combining pesticides and fertilizers, it not only simplifies agricultural operations but also improves the utilization efficiency of fertilizers and pesticides. However, existing pesticide and fertilizer formulations have problems such as limited application scope, high technical barriers to use, and poor environmental friendliness. Among them, silica microcapsules are widely used in the pesticide and fertilizer field due to their good chemical stability and biocompatibility, as well as a certain sustained-release effect. However, the traditional preparation method of silica microcapsules usually requires the use of acid-base catalysts, which not only easily leads to the degradation of sensitive drugs, but also places high demands on the process flow and equipment. At the same time, in actual application, the release rate of silica microcapsules is also easily affected by environmental factors (such as soil pH), resulting in poor sustained-release effect and a short lasting effect. Summary of the Invention

[0003] Based on this, it is necessary to provide a microcapsule slow-release fertilizer and its preparation method and application to address the above problems. The microcapsule slow-release fertilizer not only has excellent slow-release performance, environmental adaptability and environmental friendliness, but also has strong stability, good dispersibility and long lasting effect, thereby significantly improving the utilization rate of fertilizer and crop disease resistance. At the same time, no acid-base catalyst is required in the preparation process, the process is simple and the production cost is low.

[0004] A microcapsule slow-release medicinal fertilizer comprises a capsule core and a capsule wall. The capsule core is made of a water-soluble pesticide and fertilizer, and the capsule wall is made of silicon dioxide and calcium carbonate. The mass ratio of the silicon dioxide to the calcium carbonate is 0.7:1-1.6:1. The microcapsule slow-release medicinal fertilizer has a median particle size of 0.5 μm-5 μm and a surface potential of -30 mV to -52 mV.

[0005] In one embodiment, the mass fraction of the capsule core in the microcapsule slow-release medicinal fertilizer is 20%-45%.

[0006] In one embodiment, the mass ratio of the water-soluble pesticide to the fertilizer is 1:0.8-1:5.

[0007] In one embodiment, the water-soluble pesticide is selected from at least one of bensulfuron-methyl, tetramycin, bensulfuron-methyl, and 2-methyl-4-chloro-1-methyl sodium salt;

[0008] And / or, the fertilizer is selected from at least one of nitrogen fertilizer, potassium fertilizer, trace element fertilizer or rare earth element fertilizer.

[0009] The microcapsule slow-release fertilizer of the present invention uses silicon dioxide and calcium carbonate as the material of the capsule wall, limits the mass ratio of silicon dioxide and calcium carbonate, and limits the median particle size and surface potential of the microcapsule slow-release fertilizer. On the one hand, the synergistic effect of silicon dioxide and calcium carbonate can be fully utilized, so that the microcapsule slow-release fertilizer has excellent slow-release performance, environmental adaptability and environmental friendliness, while the capsule wall has good mechanical strength and stability, effectively extending the lasting period; on the other hand, the microcapsule slow-release fertilizer particle size is small and the particle distribution is uniform, which is conducive to improving the performance stability of the microcapsule slow-release fertilizer, and good dispersibility, which can further extend the lasting period. Therefore, the microcapsule slow-release fertilizer of the present invention not only has excellent slow-release performance, environmental adaptability and environmental friendliness, but also has strong stability, good dispersibility and long lasting period, thereby significantly improving the utilization rate of fertilizer and crop disease resistance.

[0010] A method for preparing the microcapsule slow-release medicinal fertilizer comprises the following steps:

[0011] preparing an aqueous solution by mixing water-soluble pesticides, fertilizers and water;

[0012] preparing an oil phase solution with an emulsifier and a hydrophobic organic solvent;

[0013] Mixing the aqueous phase solution and the oil phase solution, and emulsifying them to obtain an emulsion;

[0014] adding a calcium surfactant aqueous solution to the emulsion, and then adding a carbonate aqueous solution, and reacting under stirring to obtain a first reaction solution;

[0015] Silicate is added to the first reaction liquid, reacted under stirring conditions, and then separated and dried to obtain microcapsule slow-release fertilizer, wherein the mass ratio of the calcium surfactant to the silicate is 1:2-1:5.

[0016] In one embodiment, the particle size of the droplets in the emulsion is 0.5 μm-2.0 μm.

[0017] In one embodiment, in the step of reacting to form silicon dioxide under stirring conditions, the reaction temperature is 25° C.-80° C., and the reaction time is 5 h-8 h.

[0018] In one embodiment, the raw materials for preparing the microcapsule slow-release fertilizer include the following components, in parts by weight: 0.5-1.5 parts of the water-soluble pesticide, 1-8 parts of the fertilizer, 18-20 parts of the hydrophobic organic solvent, 1-2 parts of the emulsifier, 0.05-0.5 parts of the calcium surfactant, 0.04-0.1 parts of the carbonate, 0.5-1.5 parts of the silicate and 8-15 parts of water.

[0019] In one embodiment, the water-soluble pesticide is selected from at least one of bensulfuron-methyl, tetramycin, bensulfuron-methyl, and 2-methyl-4-chloro-1-methyl sodium salt;

[0020] And / or, the fertilizer is selected from at least one of nitrogen fertilizer, potassium fertilizer, trace element fertilizer or rare earth element fertilizer;

[0021] and / or, the calcium surfactant is selected from at least one of calcium dodecylbenzenesulfonate, calcium ligninsulfonate or calcium stearate;

[0022] And / or, the silicate is selected from tetraethyl silicate and / or methyl silicate.

[0023] The present invention discloses a method for preparing a microcapsule-based slow-release fertilizer. Using a biomineralization-like technique, silicate is used as a silicon source, calcium ions are used as an auxiliary substance, and the mass ratio of the calcium surfactant to the silicate is regulated. Microcapsules containing a capsule wall composed of silicon dioxide and calcium carbonate in a specific mass ratio are synthesized under mild conditions without acid or base catalysis. The synergistic effect of silicon dioxide and calcium carbonate is utilized to achieve excellent slow release of pesticides and fertilizers, improving crop disease resistance and fertilizer utilization efficiency while reducing environmental pollution. This method is simple, low-cost, suitable for large-scale production, and has broad application prospects.

[0024] An application of the microcapsule slow-release fertilizer in preventing and controlling plant diseases and insect pests. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a microscope wet mount image of the microcapsule slow-release medicinal fertilizer prepared in Example 5 of the present invention;

[0027] Figure 2 This is a microscope image of the microcapsule slow-release medicinal fertilizer prepared in Example 5 of the present invention;

[0028] Figure 3 This is a transmission electron micrograph of the microcapsule slow-release medicinal fertilizer prepared in Example 5 of the present invention;

[0029] Figure 4 This is a microscope dry film image of the microcapsule slow-release medicinal fertilizer prepared in Comparative Example 1 of the present invention;

[0030] Figure 5This is a microscope dry film image of the microcapsule slow-release fertilizer prepared in Comparative Example 2 of the present invention;

[0031] Figure 6 This is a particle size distribution diagram of the microcapsule slow-release medicinal fertilizer prepared in Example 5 of the present invention;

[0032] Figure 7 This is a comparison of the surface potentials of the microcapsule slow-release medicated fertilizer prepared in Example 5 of the present invention and the non-medicated silicon-calcium microcapsules prepared in Comparative Example 11, wherein A represents the microcapsule slow-release medicated fertilizer prepared in Example 5, and B represents the non-medicated silicon-calcium microcapsules prepared in Comparative Example 11;

[0033] Figure 8 This is a graph showing the release behavior of the microcapsule slow-release medicated fertilizer prepared in Example 5 of the present invention in an acidic environment (pH 5);

[0034] Figure 9 This is a graph showing the release behavior of the microcapsule slow-release fertilizer prepared in Example 5 of the present invention under a neutral environment (pH 7);

[0035] Figure 10 This is a graph showing the release behavior of the microcapsule slow-release fertilizer prepared in Example 5 of the present invention in an alkaline environment (pH 9);

[0036] Figure 11 This is a comparison chart of the indoor toxicity test of the microcapsule slow-release fertilizer prepared in Example 5 of the present invention, the commercially available benomyl soluble powder, and the calcium silicate microcapsules without the drug against watermelon wilt pathogen. In the figure, A represents the commercially available benomyl soluble powder, B represents the microcapsule slow-release fertilizer prepared in Example 5, and C represents the calcium silicate microcapsules;

[0037] Figure 12 This is a comparative graph showing the potted plant control effects of the microcapsule slow-release fertilizer prepared in Example 5 of the present invention, the commercially available benomyl soluble powder, the drug-free calcium silicate microcapsules prepared in Comparative Example 11, and deionized water (ck) on watermelon wilt; wherein, in the figure, A represents deionized water, B represents the commercially available benomyl soluble powder, C represents the microcapsule slow-release fertilizer prepared in Example 5, and D represents the drug-free calcium silicate microcapsules prepared in Comparative Example 11;

[0038] Figure 13This is a comparison chart of the fresh weight of watermelon seedlings after treatment with the microcapsule slow-release fertilizer prepared in Example 5 of the present invention, the commercially available benomyl soluble powder, the drug-free calcium silicate microcapsules prepared in Comparative Example 11, and deionized water (ck); wherein, in the figure, A represents deionized water, B represents the drug-free calcium silicate microcapsules prepared in Comparative Example 11, C represents the commercially available benomyl soluble powder, and D represents the microcapsule slow-release fertilizer prepared in Example 5. Different lowercase letters (a, b, c) in the figure indicate significant differences between the treatments (p<0.05, Duncan test; mean ± standard deviation, n=3), and the differences between treatments containing the same letter (e.g., a and ab, b and ab) are not significant;

[0039] Figure 14 This is a comparison of the chlorophyll content of watermelon seedlings after treatment with the microcapsule slow-release fertilizer prepared in Example 5 of the present invention, the commercially available benomyl soluble powder, the drug-free calcium silicate microcapsules prepared in Comparative Example 11, and deionized water (ck); wherein in the figure, A represents deionized water, B represents the drug-free calcium silicate microcapsules prepared in Comparative Example 11, C represents the commercially available benomyl soluble powder, and D represents the microcapsule slow-release fertilizer prepared in Example 5, and different lowercase letters (a, b, c) in the figure indicate significant differences between the treatments (p<0.05, Duncan test; mean ± standard deviation, n=3), and the differences between treatments containing the same letter (e.g., b and bc, c and bc) are not significant;

[0040] Figure 15 This is a comparison of the plant heights of watermelon seedlings after treatment with the microcapsule slow-release fertilizer prepared in Example 5 of the present invention, the commercially available benomyl soluble powder, the drug-free calcium silicate microcapsules prepared in Comparative Example 11, and deionized water (ck); wherein in the figure, A represents deionized water, B represents the drug-free calcium silicate microcapsules prepared in Comparative Example 11, C represents the commercially available benomyl soluble powder, and D represents the microcapsule slow-release fertilizer prepared in Example 5, and different lowercase letters (a, b, c) in the figure indicate significant differences between the treatments (p<0.05, Duncan test; mean ± standard deviation, n=3), and the differences between treatments containing the same letter (e.g., b and bc, c and bc) are not significant;

[0041] Figure 16 This is a comparison of the root lengths of watermelon seedlings after treatment with the microcapsule slow-release fertilizer prepared in Example 5 of the present invention, the commercially available benomyl soluble powder, the drug-free calcium silicate microcapsules prepared in Comparative Example 11, and deionized water (ck); wherein, in the figure, A represents deionized water, B represents the drug-free calcium silicate microcapsules prepared in Comparative Example 11, C represents the commercially available benomyl soluble powder, and D represents the microcapsule slow-release fertilizer prepared in Example 5, and the lowercase letter a in the figure indicates that there was no significant difference among the treatments (p<0.05, Duncan test; mean ± standard deviation, n=3);

[0042] Figure 17 This is a comparison chart of the potted control effects of the microcapsule slow-release fertilizer prepared in Example 5 of the present invention and the commercially available benomyl soluble powder on watermelon wilt; wherein, in the figure, A represents the commercially available benomyl soluble powder, and B represents the microcapsule slow-release fertilizer prepared in Example 5. DETAILED DESCRIPTION

[0043] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments or embodiments and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, including any two related listed items, any more related listed items, or the combination of all related listed items.

[0045] The microcapsule slow-release medicinal fertilizer provided by the present invention comprises a capsule core and a capsule wall. The materials of the capsule core comprise water-soluble pesticides and fertilizers, and the materials of the capsule wall comprise silicon dioxide and calcium carbonate. The mass ratio of the silicon dioxide to the calcium carbonate is 0.7:1-1.6:1. The median particle size of the microcapsule slow-release medicinal fertilizer is 0.5 μm-5 μm, and the surface potential is -30 mV to -52 mV.

[0046] In the present invention, water-soluble pesticides and fertilizers are used as capsule core materials, silicon dioxide and calcium carbonate are used as capsule wall materials, and the mass ratio of silicon dioxide to calcium carbonate is limited. By giving full play to the synergistic effect of silicon dioxide and calcium carbonate, on the one hand, silicon dioxide is used to provide excellent chemical stability and biocompatibility, while calcium carbonate enhances the mechanical strength and sustained-release performance of the capsule wall, thereby ensuring that water-soluble pesticides and fertilizers are continuously released within a target time and improving the utilization rate of the pesticide and fertilizer. At the same time, calcium carbonate can also adjust the pH value of acidic soil and realize the intelligent release of pesticides and fertilizers in an acidic environment, so that the microcapsule sustained-release pesticide and fertilizer is not easily affected by environmental factors and has good environmental adaptability, thereby realizing efficient encapsulation and controllable release of drugs and fertilizers, improving the utilization rate of pesticides and fertilizers and disease resistance. On the other hand, after the capsule wall is degraded, silicon fertilizer and calcium fertilizer can be provided to crops, promoting crop growth and enhancing disease resistance and stress resistance, further improving the disease resistance of crops, while reducing environmental pollution and improving environmental friendliness.

[0047] At the same time, by limiting the median particle size and surface potential of the microcapsule slow-release fertilizer, on the one hand, it can ensure that the microcapsule slow-release fertilizer has a higher specific surface area to promote the release of pesticides and fertilizers, further improve the slow-release effect and extend the effective period; on the other hand, it can avoid the agglomeration problem caused by too small particle size, so that the microcapsule slow-release fertilizer has good dispersion stability during the application process, can be evenly distributed in crops or soil and be efficiently absorbed, further improving the utilization rate of fertilizers and the disease resistance of crops.

[0048] Therefore, the microcapsule slow-release fertilizer of the present invention uses silicon dioxide and calcium carbonate as capsule wall materials, limits the mass ratio of silicon dioxide and calcium carbonate, and limits the median particle size and surface potential of the microcapsule slow-release fertilizer. Under this synergistic effect, the microcapsule slow-release fertilizer of the present invention not only has excellent slow-release performance, environmental adaptability and environmental friendliness, but also has strong stability, good dispersibility and long lasting effect, thereby significantly improving the utilization rate of the fertilizer and the disease resistance of crops.

[0049] Optionally, the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 20%-45%. Specifically, the mass fraction of the capsule core in the microcapsule slow-release fertilizer includes but is not limited to 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 45%, etc. Such an arrangement can better balance the relationship between the slow-release effect, release rate and stability of the microcapsule slow-release fertilizer by controlling the dosage of the capsule core, thereby better regulating the release rate and slow-release performance of the microcapsule slow-release fertilizer, while better ensuring the stability of the efficacy and extending the duration of the effect.

[0050] Optionally, the mass ratio of the water-soluble pesticide to the fertilizer is 1:0.8-1:5. Specifically, the mass ratio of the water-soluble pesticide to the fertilizer includes but is not limited to 1:0.8, 1:1, 1:1.5, 1:2, 1:3, 1:5, etc. Such an arrangement can better balance the relationship between drug efficacy and fertilizer efficacy by adjusting the mass ratio of the water-soluble pesticide to the fertilizer, better ensuring that the microcapsule slow-release fertilizer provides rich nutrients to crops, promotes crop growth, and improves the disease resistance of crops; it is also conducive to further reducing pesticide pollution to the environment.

[0051] Optionally, the water-soluble pesticide is selected from at least one of bensulfuron-methyl, tetramycin, bensulfuron-methyl, and 2-Methyl-4-chloro-1-methyl sodium salt.

[0052] Optionally, the fertilizer is selected from at least one of nitrogen fertilizer, potassium fertilizer, trace element fertilizer or rare earth element fertilizer; wherein the nitrogen fertilizer is preferably urea.

[0053] It should be noted that, in the present invention, the dosage form of the microcapsule slow-release fertilizer can be granular, suspension, etc., preferably granular; at the same time, the mass fraction of the water-soluble pesticide in the microcapsule slow-release fertilizer in the present invention is 7.62%-26.55%, and the encapsulation efficiency is 76%-85%.

[0054] At the same time, the present invention also provides a method for preparing the microcapsule slow-release medicinal fertilizer, comprising the following steps:

[0055] S1, preparing an aqueous solution by mixing a water-soluble pesticide, a fertilizer, and water; in step S1, the water-soluble pesticide is selected from at least one of benomyl, tetramycin, bensulfuron-methyl, and 2-Methyl-4-chloro-1-sodium salt; the fertilizer is selected from at least one of a nitrogen fertilizer, a potassium fertilizer, a trace element fertilizer, or a rare earth element fertilizer, wherein the nitrogen fertilizer is preferably urea.

[0056] S2, preparing an emulsifier and a hydrophobic organic solvent into an oil phase solution; in this step, the emulsifier is selected from at least one of sorbitan oleate (Span-80), sorbitan stearate (Span-60), and glycerol monooleate; and the hydrophobic organic solvent is selected from at least one of cyclohexanone, xylene, ethyl acetate, and cyclohexane.

[0057] S3, mixing the aqueous phase solution and the oil phase solution, and emulsifying them to obtain an emulsion; it can be understood that the emulsion is a water-in-oil emulsion to load the water-soluble pesticide.

[0058] In one embodiment, emulsification can be achieved by high-speed stirring using a stirrer, homogenizer, or the like, ultrasonic emulsification using ultrasound using an ultrasonic machine, or shear emulsification using a high-pressure homogenizer.

[0059] Optionally, the particle size of the droplets in the emulsion is 0.5 μm-2.0 μm. This configuration is conducive to better controlling the median particle size and surface potential of the microcapsule slow-release fertilizer by regulating the size of the droplets in the emulsion.

[0060] S4, adding a calcium surfactant aqueous solution to the emulsion, and then adding a carbonate aqueous solution, reacting under stirring conditions to obtain a first reaction solution; it can be understood that in this step, in the emulsion, the calcium surfactant will be adsorbed on the oil-water interface due to its own surface activity, providing a basis for the formation of calcium carbonate capsule wall; at the same time, when the carbonate aqueous solution is introduced, the carbonate will gradually react with the calcium ions in the calcium surfactant to generate calcium carbonate, which serves as part of the capsule wall material.

[0061] In the present invention, the calcium surfactant aqueous solution is obtained by mixing a calcium surfactant and water, wherein the calcium surfactant is selected from at least one of calcium dodecylbenzenesulfonate, calcium ligninsulfonate or calcium stearate, preferably calcium ligninsulfonate.

[0062] In the present invention, the carbonate aqueous solution is obtained by mixing carbonate and water, wherein the carbonate is selected from ammonium carbonate, sodium carbonate, potassium carbonate and the like.

[0063] In one embodiment, after adding the calcium surfactant aqueous solution to the emulsion, stirring is first performed for 20 min-40 min, preferably 30 min, and then adding the carbonate aqueous solution and continuing to stir for 20 min-40 min, preferably 30 min. This arrangement is conducive to ensuring that the calcium surfactant is fully adsorbed to the oil-water interface and promotes its reaction with carbonate to form calcium carbonate.

[0064] S5, adding silicate to the first reaction solution, reacting under stirring conditions, and then separating and drying to obtain microcapsule slow-release fertilizer, wherein the mass ratio of calcium surfactant to silicate is 1:2-1:5.

[0065] In step S5, when the silicate is added to the first reaction solution, the silicate will be partially hydrolyzed into a negative potential silanol prepolymer after contacting the aqueous phase. Under stirring conditions, these silanol prepolymers are continuously aggregated to the oil-water interface under the action of electrostatic force and combined with calcium ions that have not formed calcium carbonate, and promote the formation of silica nanoparticles, which together with the calcium carbonate formed in step S4 constitute the capsule wall. At the same time, a capsule core composed of fertilizer and water-soluble pesticide is also gradually formed. After separation and drying, a microcapsule slow-release fertilizer composed of the capsule wall and the capsule core is finally formed. At this time, the mass ratio of the silica to the calcium carbonate is 0.7:1-1.6:1, and the median particle size of the microcapsule slow-release fertilizer is 0.5μm-5μm, and the surface potential is -30mV to -52mV.

[0066] It is understood that the calcium surfactant provided in the present invention can provide calcium ions and, by utilizing its own surface activity, promote the distribution of calcium ions at the water-oil interface. On the one hand, some of the provided calcium ions react with carbonates to form calcium carbonate, which serves as the basis for the formation of the capsule wall. On the other hand, some of the calcium ions act as promoters, combining with silanol prepolymers generated by the hydrolysis of silicates to promote the formation of silica nanoparticles. This avoids the reliance on acid-base catalysts in traditional silica microcapsule preparation methods, simplifies the preparation process, and reduces potential damage to sensitive drugs.

[0067] Therefore, in the preparation method of the microcapsule slow-release fertilizer of the present invention, a biomineralization-like technology is used, silicate is used as a silicon source, calcium ions are used as an auxiliary substance, and the mass ratio of calcium surfactant and silicate is regulated. Microcapsules containing capsule walls composed of silicon dioxide and calcium carbonate in a specific mass ratio are synthesized under mild conditions without acid-base catalysis. The synergistic effect of silicon dioxide and calcium carbonate is utilized to achieve excellent slow release of water-soluble pesticides and fertilizers, improve crop disease resistance and fertilizer utilization rate, and reduce environmental pollution. This preparation method is simple in process, low in cost, suitable for large-scale production, and has broad application prospects.

[0068] Optionally, in the step of reacting to form silicon dioxide under stirring conditions, the reaction temperature is 25° C.-80° C. and the reaction time is 5 h-8 h. This configuration is conducive to better forming microcapsule slow-release fertilizer with small particle size and uniform particle distribution.

[0069] Optionally, the silicate is selected from tetraethyl silicate and / or methyl silicate, preferably tetraethyl silicate.

[0070] Optionally, the raw materials for preparing the microcapsule slow-release fertilizer include the following components, measured in parts by weight: 0.5-1.5 parts of the water-soluble pesticide, 1-8 parts of the fertilizer, 18-20 parts of the hydrophobic organic solvent, 1-2 parts of the emulsifier, 0.05-0.5 parts of the calcium surfactant, 0.04-0.1 parts of the carbonate, 0.5-1.5 parts of the silicate, and 8-15 parts of water. With this arrangement, the performance of the microcapsule slow-release fertilizer can be further controlled by regulating the components of each raw material.

[0071] It should be noted that the weight parts of water mentioned in the above components of the present invention are the sum of the weight parts of water in the aqueous phase, the weight parts of water in the calcium surfactant aqueous solution and the weight parts of water in the carbonate aqueous solution.

[0072] It can be seen that the microcapsule slow-release fertilizer of the present invention not only has excellent slow-release performance, environmental adaptability and environmental friendliness, but also has strong stability, good dispersibility and long lasting effect, thereby significantly improving the utilization rate of fertilizer and crop disease resistance. At the same time, no acid-base catalyst is required in the preparation process, the process is simple and the production cost is low.

[0073] In addition, the present invention also provides an application of the microcapsule slow-release fertilizer in preventing and controlling plant diseases and insect pests.

[0074] The microcapsule slow-release fertilizer and its preparation method and application will be further described below by the following specific examples. However, it will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially. At the same time, it should be noted that the relevant raw materials involved in the embodiments of the present invention and the comparative examples are specifically as follows: wherein, trace fertilizer refers to trace element fertilizer, that is, is the abbreviation of trace element fertilizer, and the brand is Yinhai Chemical, purchased from Zhengzhou Yinzhihai Chemical Products Co., Ltd.; benzamethylenetetramine, model R093280-100g, purchased from Shanghai Linen Technology Development Co., Ltd.; urea, model S30375-500g; calcium lignin sulfonate, model S50911-100g; all purchased from Shanghai Yuanye Biotechnology Co., Ltd.; tetramycin, model Q / LW005-2016, purchased from Liaoning Weike Bioengineering Co., Ltd.; benzylsulfuron-methyl, model B109903-1g, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; monoolein, model g0082; purchased The emulsifiers were purchased from Tokyo Institute of Technology (Shanghai) Chemical Industry Development Co., Ltd.; the emulsifier sorbitan oleate (SPAN-80), model S817933-500 mL; ammonium carbonate, model A800845-500 g; tetraethyl silicate, model T819505-500 mL; cyclohexanone, model c805636-500 mL; xylene, model x820584-25 mL; ethyl acetate, model e809178-100 mL; and sodium carbonate, model s818017-100 g were all purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; the emulsifier sorbitan stearate (SPAN-60), model cs10401-100 mL was purchased from Beijing Coolbo Technology Co., Ltd.; and cyclohexane was purchased from Xilong Science Co., Ltd.

[0075] Example 1

[0076] An aqueous phase solution is prepared by mixing 1 part by weight of benomyl, 0.5 parts by weight of micronutrient fertilizer, 1.5 parts by weight of urea, and 3 parts by weight of deionized water; an oil phase solution is prepared by mixing 1.5 parts by weight of sorbitan oleate (SPAN-80) and 20 parts by weight of cyclohexanone; a calcium lignin sulfonate aqueous solution is prepared by mixing 0.5 parts by weight of calcium lignin sulfonate and 2 parts by weight of deionized water; and an ammonium carbonate aqueous solution is prepared by mixing 0.1 parts by weight of ammonium carbonate and 2 parts by weight of deionized water.

[0077] The oil phase solution and the aqueous phase solution obtained above were mixed and ultrasonically emulsified for 1 minute to obtain an emulsion, wherein the particle size of the droplets in the emulsion was 1.2 μm; then the calcium lignin sulfonate aqueous solution obtained above was added to the emulsion, and after stirring for 30 minutes, the ammonium carbonate aqueous solution obtained above was added and continued to stir for 30 minutes to react to form calcium carbonate, thereby obtaining a first reaction solution; then 1 part by weight of tetraethyl silicate was added to the first reaction solution, and the mixture was reacted at 50° C. for 6 hours under stirring to obtain a brown-yellow reaction solution; the brown-yellow reaction solution was centrifuged to collect the precipitate, and finally dried to obtain a microcapsule sustained-release fertilizer, wherein the mass fraction of the capsule core in the microcapsule sustained-release fertilizer was 35%, and the mass fraction of carbendazim in the capsule core was 15.15%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate was 1.2:1, and the median particle size of the microcapsule sustained-release fertilizer was approximately 2.1 μm, the surface potential was -45.2 mV, and the encapsulation efficiency was 83%.

[0078] Example 2

[0079] 0.5 parts by weight of benomyl, 0.1 parts by weight of micronutrient fertilizer, 1 part by weight of urea, and 6 parts by weight of deionized water are mixed to obtain an aqueous phase solution; 2 parts by weight of sorbitan oleate (Span-80) and 18 parts by weight of xylene are mixed to obtain an oil phase solution; 0.3 parts by weight of calcium lignin sulfonate and 2 parts by weight of deionized water are mixed to obtain a calcium lignin sulfonate aqueous solution; and 0.06 parts by weight of ammonium carbonate and 2 parts by weight of deionized water are mixed to obtain an ammonium carbonate aqueous solution.

[0080] The oil phase solution and the aqueous phase solution obtained above were mixed and ultrasonically emulsified for 1 minute to obtain an emulsion, wherein the particle size of the droplets in the emulsion was 1.5 μm; then the calcium lignin sulfonate aqueous solution obtained above was added to the emulsion, and after stirring for 25 minutes, the ammonium carbonate aqueous solution obtained above was added and continued to stir for 1 hour to react to form calcium carbonate, thereby obtaining a first reaction solution; then 1.5 parts by weight of tetraethyl silicate was added to the first reaction solution, and the mixture was reacted at 40° C. under stirring for 7 hours to obtain a brown-yellow reaction solution; the brown-yellow reaction solution was centrifuged to collect the precipitate, and finally dried to obtain a microcapsule sustained-release fertilizer, wherein the mass fraction of the capsule core in the microcapsule sustained-release fertilizer was 28%, and the mass fraction of carbendazim in the capsule core was 7.62%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate was 0.8:1, and the median particle size of the microcapsule sustained-release fertilizer was about 2.5 μm, the surface potential was -35.2 mV, and the encapsulation efficiency was 82%.

[0081] Example 3

[0082] 1.5 parts by weight of benomyl, 1.2 parts by weight of urea, and 7 parts by weight of deionized water are mixed to obtain an aqueous phase solution; 2 parts by weight of sorbitan stearate (Span-60) and 20 parts by weight of ethyl acetate are mixed to obtain an oil phase solution; 0.2 parts by weight of calcium lignin sulfonate and 2 parts by weight of deionized water are mixed to obtain a calcium lignin sulfonate aqueous solution; and 0.04 parts by weight of sodium carbonate and 2 parts by weight of deionized water are mixed to obtain a sodium carbonate aqueous solution.

[0083] The oil phase solution and the aqueous phase solution obtained above were mixed and ultrasonically emulsified for 2 minutes to obtain an emulsion, wherein the particle size of the droplets in the emulsion was 1.0 μm; then the calcium lignin sulfonate aqueous solution obtained above was added to the emulsion, and after stirring for 25 minutes, the sodium carbonate aqueous solution obtained above was added and continued to stir for 35 minutes to react to form calcium carbonate, thereby obtaining a first reaction solution; then 1.5 parts by weight of tetraethyl silicate was added to the first reaction solution, and the mixture was reacted at 40° C. under stirring for 7 hours to obtain a brown-yellow reaction solution; the brown-yellow reaction solution was centrifuged to collect the precipitate, and finally dried to obtain a microcapsule sustained-release fertilizer, wherein the mass fraction of the capsule core in the microcapsule sustained-release fertilizer was 40%, and the mass fraction of carbendazim in the capsule core was 26.65%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate was 1.5:1, and the median particle size of the microcapsule sustained-release fertilizer was about 2 μm, the surface potential was -50.1 mV, and the encapsulation efficiency was 76%.

[0084] Example 4

[0085] 1 part by weight of benomyl, 0.5 parts by weight of micronutrient fertilizer, 1.5 parts by weight of urea and 4 parts by weight of deionized water are mixed to obtain an aqueous phase solution; 1.5 parts by weight of glyceryl monooleate and 18 parts by weight of cyclohexane are mixed to obtain an oil phase solution; 0.5 parts by weight of calcium stearate and 2 parts by weight of deionized water are mixed to obtain a calcium stearate aqueous solution; and 0.1 parts by weight of sodium carbonate and 2 parts by weight of deionized water are mixed to obtain a sodium carbonate aqueous solution.

[0086] The oil phase solution and the aqueous phase solution obtained above were mixed and ultrasonically emulsified for 2 minutes to obtain an emulsion, wherein the particle size of the droplets in the emulsion was 0.8 μm; then the calcium stearate aqueous solution obtained above was added to the emulsion, and after stirring for 35 minutes, the sodium carbonate aqueous solution obtained above was added and continued to stir for 35 minutes to react to form calcium carbonate, thereby obtaining a first reaction solution; then 0.5 parts by weight of tetraethyl silicate was added to the first reaction solution, and the mixture was reacted at 30° C. under stirring for 8 hours to obtain a brown-yellow reaction solution; the brown-yellow reaction solution was centrifuged to collect the precipitate, and finally dried to obtain microcapsule slow-release fertilizer particles, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer was 32%, and the mass fraction of carbendazim in the capsule core was 16.67%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate was 1:1, and the median particle size of the microcapsule slow-release fertilizer was about 1.5 μm, the surface potential was -48.3 mV, and the encapsulation efficiency was 83%.

[0087] Example 5

[0088] An aqueous phase solution is prepared by mixing 1 part by weight of benomyl, 0.5 parts by weight of micronutrient fertilizer, 1.5 parts by weight of urea, and 3 parts by weight of deionized water; an oil phase solution is prepared by mixing 1.5 parts by weight of sorbitan oleate (Span-80) and 20 parts by weight of cyclohexane; a calcium lignin sulfonate aqueous solution is prepared by mixing 0.05 parts by weight of calcium lignin sulfonate and 2 parts by weight of deionized water; and an ammonium carbonate aqueous solution is prepared by mixing 0.1 parts by weight of ammonium carbonate and 2 parts by weight of deionized water.

[0089] The oil phase solution and the aqueous phase solution obtained above were mixed and ultrasonically emulsified for 2 minutes to obtain an emulsion, wherein the particle size of the droplets in the emulsion was 1.0 μm; then the calcium lignin sulfonate aqueous solution obtained above was added to the emulsion, and after stirring for 35 minutes, the ammonium carbonate aqueous solution obtained above was added and continued to stir for 35 minutes to react to form calcium carbonate, thereby obtaining a first reaction solution; then 1 part by weight of tetraethyl silicate was added to the first reaction solution, and the mixture was reacted at 60° C. under stirring for 5 hours to obtain a brown-yellow reaction solution; the brown-yellow reaction solution was centrifuged to collect the precipitate, and finally dried to obtain microcapsule slow-release fertilizer particles, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer was 30%, and the mass fraction of carbendazim in the capsule core was 15.45%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate was 1.1:1, and the median particle size of the microcapsule slow-release fertilizer was about 1.5 μm, the surface potential was -47.5 mV, and the encapsulation efficiency was 85%.

[0090] from Figure 1-3 It can be seen from the figure that the microcapsule slow-release fertilizer particles prepared in this example are spherical, with a median particle size of about 1.5 μm, and a uniform particle size distribution.

[0091] Example 6

[0092] 0.6 parts by weight of benomyl, 0.5 parts by weight of micronutrient fertilizer, 1 part by weight of urea and 2 parts by weight of deionized water are mixed to obtain an aqueous phase solution; 1 part by weight of sorbitan stearate (Span-60) and 20 parts by weight of xylene are mixed to obtain an oil phase solution; 0.1 parts by weight of calcium stearate and 2 parts by weight of deionized water are mixed to obtain a calcium stearate aqueous solution; and 0.1 parts by weight of sodium carbonate and 2 parts by weight of deionized water are mixed to obtain a sodium carbonate aqueous solution.

[0093] The oil phase solution and the aqueous phase solution obtained above were mixed and ultrasonically emulsified for 2 minutes to obtain an emulsion, wherein the particle size of the droplets in the emulsion was 1.3 μm; then the calcium stearate aqueous solution obtained above was added to the emulsion, and after stirring for 30 minutes, the sodium carbonate aqueous solution obtained above was added and continued to stir for 30 minutes to react to form calcium carbonate, thereby obtaining a first reaction solution; then 0.5 parts by weight of tetraethyl silicate was added to the first reaction solution, and the mixture was reacted at 70° C. under stirring for 5 hours to obtain a brown-yellow reaction solution; the brown-yellow reaction solution was centrifuged, the precipitate was collected, and finally dried to obtain microcapsule slow-release fertilizer particles, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer was 25%, and the mass fraction of carbendazim in the capsule core was 11.48%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate was 0.9:1, and the median particle size of the microcapsule slow-release fertilizer was approximately 2.0 μm, the surface potential was -43.8 mV, and the encapsulation efficiency was 80%.

[0094] Example 7

[0095] Example 7 is different from Example 1 only in that, in the aqueous phase solution, equal weight parts of tetramycin are used instead of benomyl; in the oil phase solution, equal weight parts of calcium dodecylbenzenesulfonate are used instead of calcium ligninsulfonate, and the other conditions are the same. The particle size of the droplets in the emulsion is 1.4 μm; microcapsule slow-release fertilizer particles are obtained, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 38%, and the mass fraction of tetramycin in the capsule core is 25%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 1.3:1, and the median particle size of the microcapsule slow-release fertilizer is about 2.5 μm, the surface potential is -49.6 mV, and the encapsulation efficiency is 82%.

[0096] Example 8

[0097] Example 8 is compared with Example 1, except that, in the aqueous phase solution, equal parts by weight of bensulfuron-methyl are used instead of benzamethylenetetramine; equal parts by weight of methyl silicate are used instead of tetraethyl silicate, and the other conditions are the same, and the particle size of the droplets in the emulsion is 0.9 μm; microcapsule slow-release fertilizer particles are obtained, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 36%, and the mass fraction of bensulfuron-methyl in the capsule core is 25%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 1.4:1, and the median particle size of the microcapsule slow-release fertilizer is about 1.8 μm, the surface potential is -46.9 mV, and the encapsulation efficiency is 82%.

[0098] Example 9

[0099] Example 9 is different from Example 1 only in that the oil phase solution and the aqueous phase solution obtained above are mixed and ultrasonically emulsified for 5 minutes to obtain an emulsion, wherein the particle size of the droplets in the emulsion is 0.4 μm; the other conditions are the same, and microcapsule slow-release fertilizer particles are obtained, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 22%, and the mass fraction of bensulfuron-methyl in the capsule core is 18%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 0.7:1, and the median particle size of the microcapsule slow-release fertilizer is about 1.2 μm, the surface potential is -31.5 mV, and the encapsulation efficiency is 80%.

[0100] Example 10

[0101] Compared with Example 1, Example 10 differs only in that the oil phase solution and the aqueous phase solution obtained above are mixed and ultrasonically emulsified for 0.2 min to obtain an emulsion, wherein the particle size of the droplets in the emulsion is 2.5 μm; the other conditions are the same, and microcapsule slow-release fertilizer particles are obtained, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 45%, and the mass fraction of bensulfuron-methyl in the capsule core is 32%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 1.6:1, and the median particle size of the microcapsule slow-release fertilizer is about 4.80 μm, the surface potential is -52.0 mV, and the encapsulation efficiency is 93%.

[0102] Comparative Example 1

[0103] Comparative Example 1 is compared with Example 1, except that the calcium lignin sulfonate aqueous solution and the sodium carbonate aqueous solution are not added to the emulsion, that is, 1.5 parts by weight of tetraethyl silicate are directly added to the emulsion, and the mixture is reacted at 40°C for 7 hours under stirring to obtain a brown-yellow reaction solution; the other conditions are the same, and microcapsule slow-release fertilizer particles are obtained, wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 15%, and the mass fraction of bensulfuron-methyl in the capsule core is 10%; the material of the capsule wall is silicon dioxide, and the median particle size of the microcapsule slow-release fertilizer is about 4.5 μm, the surface potential is -28.2 mV, and the encapsulation efficiency is 60%.

[0104] from Figure 4 It can be seen that the comparative example does not contain an aqueous solution of calcium lignin sulfonate and an aqueous solution of sodium carbonate, so that calcium carbonate cannot be formed as the basis of the capsule wall. At the same time, calcium ions cannot be provided as a promoter to promote the formation of silica particles from the silanol prepolymer. Therefore, it is difficult to form a silica capsule wall and the particle size distribution is uneven.

[0105] Comparative Example 2

[0106] Comparative Example 2 is compared with Example 1, except that tetraethyl silicate is not added to the first reaction solution, that is, the first reaction solution obtained above is directly reacted at 40 ° C. for 7 h under stirring, and then centrifuged to collect the precipitate, and finally dried to obtain a microcapsule slow-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 10%, and the mass fraction of bensulfuron-methyl in the capsule core is 8%; the material of the capsule wall is calcium carbonate, and the median particle size of the microcapsule slow-release fertilizer is about 5.0 μm, the surface potential is -25.7 mV, and the encapsulation efficiency is 55%.

[0107] from Figure 5 It can be seen from the figure that the comparative example can only form microcapsules with calcium carbonate as the capsule wall due to the lack of silicon source, and the morphology of the finally obtained microcapsule slow-release fertilizer is not obvious and the capsule formation rate is poor.

[0108] Comparative Example 3

[0109] Comparative Example 3 is compared with Example 1, except that the calcium lignin sulfonate aqueous solution and the sodium carbonate aqueous solution are added to the emulsion at the same time, that is, the calcium lignin sulfonate aqueous solution and the sodium carbonate aqueous solution are added to the emulsion and stirred for 60 minutes to react to form calcium carbonate to obtain a first reaction solution; the other conditions are the same, and a microcapsule slow-release fertilizer is obtained; wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 20%, and the mass fraction of bensulfuron-methyl in the capsule core is 15%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 0.3:1, and the median particle size of the microcapsule slow-release fertilizer is about 3.2 μm, the surface potential is -15.4 mV, and the encapsulation efficiency is 65%.

[0110] Comparative Example 4

[0111] Comparative Example 4 is compared with Example 1, except that an aqueous solution of calcium chloride of equal mass concentration is used instead of an aqueous solution of calcium lignin sulfonate, and the other conditions are the same, to obtain a microcapsule slow-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 18%, and the mass fraction of bensulfuron-methyl in the capsule core is 12%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 25:1, and the median particle size of the microcapsule slow-release fertilizer is about 2.0 μm, the surface potential is -18.9 mV, and the encapsulation efficiency is 70%.

[0112] Comparative Example 5

[0113] Comparative Example 5 is compared with Example 1, except that the weight portion of calcium lignin sulfonate is 0.5, the weight portion of tetraethyl silicate is 0.1, and the other conditions are the same, to obtain a microcapsule slow-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 12%, and the mass fraction of bensulfuron-methyl in the capsule core is 9%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 0.1:1, and the median particle size of the microcapsule slow-release fertilizer is about 6.0 μm, the surface potential is -28.3 mV, and the encapsulation efficiency is 50%.

[0114] Comparative Example 6

[0115] Comparative Example 6 is compared with Example 1, except that the weight portion of calcium lignin sulfonate is 0.05, the weight portion of tetraethyl silicate is 1.5, and the other conditions are the same, to obtain a microcapsule slow-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 50%, and the mass fraction of bensulfuron-methyl in the capsule core is 30%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 2: 1, and the median particle size of the microcapsule slow-release fertilizer is about 8.0 μm, the surface potential is -15 mV, and the encapsulation efficiency is 40%.

[0116] Comparative Example 7

[0117] Comparative Example 7 is compared with Example 1, except that the ultrasonic emulsification is 15 seconds, the weight part of tetraethyl silicate is 2, and the other conditions are the same, to obtain a microcapsule sustained-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule sustained-release fertilizer is 5%, and the mass fraction of bensulfuron-methyl in the capsule core is 3%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 1.7:1, and the median particle size of the microcapsule sustained-release fertilizer is about 0.1 μm, the surface potential is -60 mV, and the encapsulation efficiency is 32%.

[0118] Comparative Example 8

[0119] Comparative Example 8 is compared with Example 1, except that the ultrasonic emulsification is performed for 5 minutes, the reaction temperature is reduced to 20°C, and the other conditions are the same, to obtain a microcapsule sustained-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule sustained-release fertilizer is 60%, and the mass fraction of bensulfuron-methyl in the capsule core is 40%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 0.5:1, and the median particle size of the microcapsule sustained-release fertilizer is about 10 μm, the surface potential is -20.5 mV, and the encapsulation efficiency is 30%.

[0120] Comparative Example 9

[0121] Comparative Example 9 is compared with Example 1, except that the weight portion of calcium lignin sulfonate is 0.1, the weight portion of sorbitan oleate (SPAN-80) is 0.2, and the other conditions are the same, to obtain a microcapsule slow-release fertilizer; wherein, the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 25%, and the mass fraction of bensulfuron-methyl in the capsule core is 18%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 1.2:1, and the median particle size of the microcapsule slow-release fertilizer is about 6.0 μm, the surface potential is -27.2 mV, and the encapsulation efficiency is 53%.

[0122] Comparative Example 10

[0123] Comparative Example 10 is compared with Example 1, except that 1.0 part by weight of calcium lignin sulfonate, 0.1 part by weight of sodium lauryl sulfate and 2 parts by weight of deionized water are mixed to obtain an aqueous solution of calcium lignin sulfonate, and the other conditions are the same to obtain a microcapsule slow-release fertilizer; wherein the mass fraction of the capsule core in the microcapsule slow-release fertilizer is 48%, and the mass fraction of bensulfuron-methyl in the capsule core is 28%; in the capsule wall material, the mass ratio of silicon dioxide to the calcium carbonate is 1.5:1, and the median particle size of the microcapsule slow-release fertilizer is about 1.2 μm, the surface potential is -60 mV, and the encapsulation efficiency is 75%.

[0124] Comparative Example 11

[0125] Comparative Example 11 differs from Example 5 only in that, in the step of preparing the aqueous solution, benomyl is not included, and the other conditions are the same, thereby obtaining drug-free calcium silica microcapsules; wherein, the mass fraction of the capsule core in the drug-free calcium silica microcapsules is 23%; in the capsule wall material, the mass ratio of silicon dioxide to calcium carbonate is 1.1:1, and the median particle size of the drug-free calcium silica microcapsules is about 1.5 μm, and the surface potential is -45.3 mV.

[0126] The following performance test is carried out using the microcapsule slow-release fertilizer prepared in Example 5 as an example. The specific test method and test results are as follows:

[0127] 1. Median particle size test: The median particle size of microcapsule slow-release fertilizer was measured using a micron laser particle size analyzer (LS-609). Specifically, the particle size was analyzed by measuring the laser shading degree of different particle sizes. Figure 6 As can be seen from the figure, the median particle size of the microcapsules of Example 5 is approximately 2.186 μm, indicating that 50% of the microcapsules have a particle size of approximately 2 μm and are normally distributed. Therefore, the microcapsules of Example 5 prepared by the present invention have a uniform particle distribution. Using both silicon dioxide and calcium carbonate as capsule wall materials, they can effectively and evenly encapsulate hydrophobic pesticides and fertilizers.

[0128] 2. Dispersion stability test: The zeta potential is used to measure the strength of mutual repulsion or attraction between particles. The smaller the molecules or dispersed particles, the higher the absolute value of the zeta potential (positive or negative), and the more stable the system. Generally, the more stable potential value is greater than or equal to +30mV or less than or equal to -30mV. Specifically, the surface potential value of the microcapsule slow-release fertilizer prepared in Example 5 was measured using a laser particle size analyzer (Mastersizer3000, UK); Figure 7 It can be seen from the figure that the system of the microcapsule slow-release fertilizer prepared in Example 5 of the present invention is evenly distributed and has high stability.

[0129] 3. Release kinetics analysis: The release behavior of the microcapsule slow-release fertilizer prepared in Example 5 under acidic, neutral and alkaline conditions was determined by the roller method. Figure 8-10 It can be seen that the maximum release amount of the microcapsule slow-release fertilizer under acidic conditions within 16 hours is 57.53%, the maximum release amount under neutral conditions is 61.07%, and the maximum release amount under alkaline conditions is 57.2%, indicating that the microcapsule slow-release fertilizer prepared in Example 5 has excellent slow-release performance, is almost unaffected by the environment, has good environmental adaptability, and thus improves the utilization rate of the fertilizer.

[0130] 4. Biological activity assay: The mycelial growth inhibition method was used to determine the indoor toxicity of the microcapsule slow-release fertilizer prepared in Example 5 against watermelon wilt. Specifically, commercially available benzyl ammonium soluble powder, the microcapsule slow-release fertilizer of Example 5, and the drug-free calcium silicate microcapsules of Comparative Example 11 were prepared to obtain test samples with concentrations of 8 μg / mL, 16 μg / mL, 32 μg / mL, 128 μg / mL, and 256 μg / mL, respectively. Deionized water (CK, as a control group) was also set as a blank control group, and the tests were carried out respectively. The test results are shown in FIG. Figure 11 As shown. Figure 11 It can be seen that the microcapsule slow-release fertilizer of Example 5 inhibits the concentration of EC 50 The commercially available soluble powder of benzylmexazol inhibits the EC at a medium concentration of 93.61 mg / L. 50The content of the microcapsule slow-release fertilizer prepared in Example 5 is 78.03 mg / L.

[0131] At the same time, the watermelon seedlings were treated with pesticides, and the spore suspension of watermelon wilt pathogen (Fusarium oxysporum watermelon-specific type) was repeatedly used to infect the seedlings. After 14 days, it was found that the microcapsule slow-release fertilizer of Example 5 had obvious disease prevention and growth-promoting effects on the watermelon seedlings. Figure 12 At the same time, the fresh weight, chlorophyll content, plant height, root length and control effect of watermelon seedlings after 14 days were tested and evaluated. The test results are as follows Figure 13-17 As shown. Figure 13-15 It can be seen that the fresh weight of watermelon seedlings using the microcapsule slow-release fertilizer of Example 5 ( Figure 13 )、chlorophyll content( Figure 14 )、Plant height( Figure 15 ) were significantly higher than CK, increasing by 109.57%, 27.65% and 39% respectively; Figure 16 It can be seen from the figure that the seedling root length of the microcapsule slow-release fertilizer treatment group of Example 5 is the longest, which is 39% longer than that of CK, indicating that the carrier can promote the root growth of watermelon seedlings; Figure 17 As can be seen from the results, the microcapsule slow-release fertilizer in Example 5 has a better control effect on watermelon wilt (62.5%) than the soluble powder of benzyl ammonium chloride (25.0%). This shows that the microcapsule slow-release fertilizer in Example 5 of the present invention has a significant disease prevention and growth-promoting effect on watermelon seedlings.

[0132] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A microcapsule slow-release medicinal fertilizer, comprising a capsule core and a capsule wall, characterized in that: The material of the capsule core includes water-soluble pesticides and fertilizers, the material of the capsule wall includes silicon dioxide and calcium carbonate, the mass ratio of the silicon dioxide to the calcium carbonate is 0.7:1-1.6:1, and the median particle size of the microcapsule slow-release fertilizer is 0.5μm-5μm, and the surface potential is -30mV to -52mV.

2. The microcapsule slow-release medicinal fertilizer according to claim 1, characterized in that The mass fraction of the capsule core in the microcapsule slow-release medicinal fertilizer is 20%-45%.

3. The microcapsule slow-release medicinal fertilizer according to claim 2, characterized in that The mass ratio of the water-soluble pesticide to the fertilizer is 1:0.8-1:

5.

4. The microcapsule slow-release medicinal fertilizer according to any one of claims 1 to 3, characterized in that: The water-soluble pesticide is selected from at least one of bensulfuron-methyl, tetramycin, bensulfuron-methyl, and 2-methyl-4-chloro-1-methyl sodium salt; And / or, the fertilizer is selected from at least one of nitrogen fertilizer, potassium fertilizer, trace element fertilizer or rare earth element fertilizer.

5. A method for preparing a microcapsule slow-release medicinal fertilizer according to any one of claims 1 to 4, characterized in that: The steps include: preparing an aqueous solution by mixing water-soluble pesticides, fertilizers and water; preparing an oil phase solution with an emulsifier and a hydrophobic organic solvent; Mixing the aqueous phase solution and the oil phase solution, and emulsifying them to obtain an emulsion; adding a calcium surfactant aqueous solution to the emulsion, and then adding a carbonate aqueous solution, and reacting under stirring to obtain a first reaction solution; Silicate is added to the first reaction liquid, reacted under stirring conditions, and then separated and dried to obtain microcapsule slow-release fertilizer, wherein the mass ratio of the calcium surfactant to the silicate is 1:2-1:

5.

6. The method for preparing the microcapsule slow-release medicinal fertilizer according to claim 5, characterized in that: The particle size of the droplets in the emulsion is 0.5 μm-2.0 μm.

7. The method for preparing the microcapsule slow-release medicinal fertilizer according to claim 5, characterized in that: In the step of reacting to form silicon dioxide under stirring conditions, the reaction temperature is 25° C.-80° C., and the reaction time is 5 h-8 h.

8. The method for preparing the microcapsule slow-release medicinal fertilizer according to any one of claims 5 to 7, characterized in that: The raw materials for preparing the microcapsule slow-release fertilizer include the following components in parts by weight: 0.5-1.5 parts of the water-soluble pesticide, 1-8 parts of the fertilizer, 18-20 parts of the hydrophobic organic solvent, 1-2 parts of the emulsifier, 0.05-0.5 parts of the calcium surfactant, 0.04-0.1 parts of the carbonate, 0.5-1.5 parts of the silicate and 8-15 parts of water.

9. The method for preparing the microcapsule slow-release medicinal fertilizer according to claim 8, characterized in that: The water-soluble pesticide is selected from at least one of bensulfuron-methyl, tetramycin, bensulfuron-methyl, and 2-methyl-4-chloro-1-methyl sodium salt; And / or, the fertilizer is selected from at least one of nitrogen fertilizer, potassium fertilizer, trace element fertilizer or rare earth element fertilizer; and / or, the calcium surfactant is selected from at least one of calcium dodecylbenzenesulfonate, calcium ligninsulfonate or calcium stearate; And / or, the silicate is selected from tetraethyl silicate and / or methyl silicate.

10. Use of the microcapsule slow-release fertilizer according to any one of claims 1 to 4 in preventing and controlling plant diseases and insect pests.

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