Insect-resistant vegetable fertilizer and preparation method thereof

Abstract

The application discloses a kind of insect-pest-resistant vegetable chemical fertilizer and preparation method thereof, and relates to the field of chemical fertilizer.The present application uses nanometer silicon dioxide as the main body of silicon fertilizer, and is sprayed and dried with sodium bicarbonate and calcium citrate to form composite microparticles, which are then mixed with self-made pH-responsive insect-pest-resistant microcapsules and sprayed on the surface of vegetable leaves.When pests feed, the acidic substances in their oral saliva react with the components in the composite microparticles, causing the local pH to rise, prompting the microcapsules to rupture, and rapidly releasing terpenoids and methyl jasmonate, which inhibit the feeding and physiological activities of pests, while inducing the activation of the defense mechanism of vegetables.The pH-responsive insect-pest-resistant microcapsules use oxidized paraffin prepared by biological enzyme catalytic oxidation method as the main wall material, and after the core material is wrapped by oil-in-water emulsification method, it is prepared by chemical cross-linking with polylactic acid-maleic anhydride copolymer, which can rapidly release the core material in weak alkaline environment, slowly release the core material in daily process, and achieve long-term insect-pest-resistant effect.The insect-pest-resistant vegetable chemical fertilizer prepared by the present application has insect-pest-resistant effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical fertilizers, in particular to a kind of insect-resistant vegetable fertilizer and preparation method thereof. BACKGROUND

[0002] In current vegetable pest control, traditional chemical pesticides have problems such as excessive residue, increased pest resistance and environmental pollution, while green control technology based on plant defense mechanism is difficult to achieve precise response to pest feeding behavior due to slow action and insufficient targeting. Although silicon fertilizer can enhance plant resistance and induce the formation of "mechanical barrier" by silicon cells, it lacks a synergistic response mechanism with pest stress when used alone.

[0003] Microcapsule slow-release technology can improve the controllability of pesticide release, but existing pH-responsive microcapsules generally have defects such as insufficient environmental friendliness of wall material, inaccurate release signal response, poor storage stability, and difficulty in forming linkage with the plant's own defense system. In addition, conventional insect-resistant ingredients are often wrapped in chemically synthesized wall materials, and their degradation products may pose potential risks to soil and crops, so there is an urgent need to develop a new type of fertilizer that is environmentally friendly, precisely responsive and long-acting.

[0004] The present application addresses the above problems by designing a synergistic system of pH-responsive insect-resistant microcapsules and silicon-based composite particles to achieve precise release upon pest feeding and dual activation of plant defense mechanisms, and using biological enzyme catalytic oxidation to prepare environmentally friendly wall materials, solving the technical bottleneck of balancing precision, long-acting and environmental friendliness in existing technologies. SUMMARY

[0005] The present application aims to provide an insect-resistant vegetable fertilizer and a preparation method thereof to solve the problems in the prior art.

[0006] To solve the above technical problems, the present application provides the following technical solution: An insect-resistant vegetable fertilizer, and a preparation method thereof, comprising the following steps:

[0007] A preparation method of an insect-resistant vegetable fertilizer, characterized in that it comprises 20-30 parts of composite particles, 20-30 parts of insect-resistant microcapsules, 10-15 parts of potassium dihydrogen phosphate and 10-15 parts of urea by weight;

[0008] The preparation method of the composite particles is as follows: nano-silicon dioxide, sodium bicarbonate, calcium citrate and deionized water are mixed in a mass ratio of 6-8:1-3:1:50, stirred at 1000 rpm for 30 min, and then spray dried to obtain composite particles with a particle size of 20-50 μm;

[0009] The preparation method of the insect-resistant microcapsules is as follows:

[0010] (1) mixing the biological enzyme with the buffer solution to prepare an enzyme activation solution with a concentration of 1 mg / ml and a pH of 6-7; mixing the powdered paraffin with the enzyme activation solution at a mass ratio of 1:0.1-0.3, stirring at 300 rpm for 10 min at 30-40°C, then adding an oxidizing agent at a rate of 2 ml / min, with the amount of the oxidizing agent being 4-6 times the mass of the paraffin, and maintaining stirring for 8-12 h, then cooling to room temperature, adding an organic solvent with the amount being 30-40 times the mass of the paraffin, stirring at 100 rpm for 10 min, then centrifuging at 4000 rpm for 10 min, removing the supernatant, distilling at 50-60°C under a vacuum of -0.1 MPa for 1-2 h, and then drying the solid in an oven at 30°C for 12 h to obtain oxidized paraffin;

[0011] (2) mixing the terpenoid compound, methyl jasmonate, and ethanol at a mass ratio of 2-4:0.5-1.5:20, stirring at 200 rpm for 10 min to obtain an oil phase solution; melting the oxidized paraffin at 60°C, mixing the melted oxidized paraffin with the surfactant, crosslinking agent, deionized water at a mass ratio of 1:0.05-0.15:0.01-0.03:10, stirring at 200 rpm for 30 min to form an aqueous phase solution; adding the aqueous phase solution to the oil phase solution, emulsifying at 2000 rpm for 30 min using an emulsifier to form an oil-in-water emulsion, then adding a polylactic acid-maleic anhydride polymer with an amount of 0.2-0.3 times the mass of the oxidized paraffin, stirring at 200 rpm at 40°C for 4 h, then filtering the reaction solution, washing the filter cake with deionized water 2-4 times, and drying at 30°C for 12 h to obtain insect-resistant microcapsules with a particle size of 400-500 μm.

[0012] Further, the particle size of the nano-silicon dioxide in step (1) is 50-100 nm.

[0013] Further, the biological enzyme in step (2) is horseradish peroxidase.

[0014] Further, the powdered paraffin in step (2) has a particle size of 100 μm.

[0015] Further, the buffer solution in step (2) is a phosphate buffer solution.

[0016] Further, the oxidizing agent in step (2) is a 30 wt% H2O2 aqueous solution.

[0017] Further, the organic solvent in step (2) is petroleum ether.

[0018] Further, the terpenoid compound in step (3) is menthol.

[0019] Further, the surfactant in step (3) is polysorbate 80.

[0020] Further, the crosslinking agent in step (3) is citric acid.

[0021] Further, the application of the fertilizer for preventing insect pests of vegetables is characterized in that the fertilizer is mixed with deionized water at a mass ratio of 1:50, and then stirred at room temperature at 150 rpm for 10 min to form a spraying solution; the spraying solution is uniformly sprayed on the leaves of the vegetables in the laboratory at a spraying amount of 50 ml per pot of vegetables, and the leaves are ensured to be completely wet but not dripping.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] The application uses self-made composite silicon fertilizer to add pH-responsive insect pest prevention microcapsules to achieve the effect of preventing insect pests.

[0024] Firstly, the application uses nanosilicon dioxide as the main body of the silicon fertilizer, and sodium bicarbonate and calcium citrate are prepared into composite microparticles through spray drying technology, and then mixed with self-made pH-responsive insect pest prevention microcapsules and sprayed on the leaves of the vegetables, so that in the process of feeding, the acidic substances in the oral cavity saliva of the pests react with the sodium bicarbonate and calcium citrate to increase the local pH value, promote the pH-responsive insect pest prevention microcapsules to break, and quickly release the effective ingredients to directly act on the oral cavity and digestive tract of the pests, inhibit the feeding and physiological activities of the pests, and at the same time, the vegetables themselves activate the defense mechanism to achieve precise response to the feeding behavior of the pests. Moreover, the microparticles of the application can induce the formation of silicified cells in the vegetables to play a "mechanical barrier" effect, increase the leaf hardness and tear resistance, and the silicon fertilizer can also enhance the stress resistance of plants and promote plant growth; the spray drying technology can control the size and morphology of the microparticles, and improve the uniformity and stability of the product.

[0025] Secondly, the self-made pH-responsive insect pest prevention microcapsules in the application use oxidized paraffin as the main wall material of the microcapsules, and after the terpenoids and methyl jasmonate core materials are wrapped by the oil-in-water emulsification method, the pH-responsive insect pest prevention microcapsules are formed by chemical crosslinking of the poly (lactic acid)-maleic anhydride copolymer under the action of a crosslinking agent. The microcapsules can not only break and quickly release the core materials in a weak alkaline environment, but also can release the core materials slowly in daily life, achieving a long-acting effect of imitating insect pests; the preparation of oxidized paraffin by biological enzyme catalytic oxidation method meets the requirements of green chemistry and is environmentally friendly and harmless, the chemical stability of oxidized paraffin is good, which can prolong the storage period of the microcapsules, and the cost is low; the poly (lactic acid)-maleic anhydride copolymer enhances the mechanical properties and thermal stability of the microcapsules through crosslinking, cooperates and amplifies the pH response signal, precisely controls the release behavior, and the maleic anhydride in the poly (lactic acid)-maleic anhydride copolymer exists in the form of polymerization, and the hydrolyzed maleic acid is a natural organic acid, which is widely present in fruits and meets the requirements of agricultural environmental protection. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the protection scope of the present application.

[0027] In order to more clearly illustrate the method provided by the present application, the following embodiments are described in detail. In the following embodiments, the test methods of various indexes of the fertilizer for preventing insect damage to vegetables are as follows.

[0028] Insect prevention performance test: 100 pots of the same kind of vegetables in the growth period were selected and divided into 10 test groups. The fertilizers prepared according to the embodiments 1-3 and the comparative examples 1-7 were uniformly sprayed on the leaves of the vegetables at a spraying amount of 50 ml per pot of vegetables, and the leaves were completely wet but not dripping. A certain amount of Plutella xylostella and aphids were put into the test groups after the spraying was completed, and other conditions were kept unchanged. After 28 days, the number of damaged leaves of diseased plants in each test group was counted.

[0029] Slow-release performance test: 2 g of the fertilizers prepared according to the embodiments 1-3 and the comparative examples 1-7 were respectively put into non-woven fabric bags and placed in soil with a depth of 5 cm and a relative humidity of 25%. Then the bags were taken out on the 1st, 7th, 14th and 28th day. After sampling, the soil adhered to the bags was slowly washed with water, and then dried in a 60°C oven for 24 h before weighing. The release rate was calculated by the change in the mass of the fertilizer before and after weighing, and the release rate = (mass before release-mass after release) / total mass.

[0030] Embodiment 1

[0031] (1) Nanometer silicon dioxide with a particle size of 50 nm, sodium bicarbonate, calcium citrate and deionized water were mixed in a mass ratio of 6:1:1:50, stirred at 1000 rpm for 30 min, and then spray dried under the following conditions: inlet temperature 150°C, gas pressure 0.1 kg / cm, pump speed 10 ml / min, and circulating air speed 0.6 m 3 / min to obtain composite microparticles with a particle size of 20 μm;

[0032] (2) horseradish peroxidase was mixed with phosphate buffer to prepare an enzyme activation solution with a concentration of 1 mg / ml and a pH of 6; 100 μm powder paraffin was mixed with the enzyme activation solution at a mass ratio of 1:0.1, and then stirred at 30°C and 300 rpm for 10 min; 30 wt% H2O2 aqueous solution was added dropwise to the mixture at a rate of 2 ml / min, and the mixture was stirred at 30°C for 8 h; the mixture was cooled to room temperature, and petroleum ether was added at a mass ratio of 30:1, and then stirred at 100 rpm for 10 min; the precipitate was removed by centrifugation at 4000 rpm for 10 min; the supernatant was distilled at 50°C and a vacuum degree of -0.1 MPa for 1 h; and the solid was dried in an oven at 30°C to constant weight to obtain oxidized paraffin;

[0033] (3) polylactic acid with a molecular weight of 800 was dried in a 60°C drying oven for 12 h, and then added to a torque rheometer together with maleic anhydride at a mass ratio of 20:1; the temperature was set to 180°C, and the stirring speed was set to 60 rpm; the mixture was mixed for 2 min, and then dicumyl peroxide was added at a mass ratio of 0.001:1; the mixture was mixed for another 8 min, and then cooled to room temperature to obtain solid microparticles; the solid microparticles were added to dichloromethane at a mass ratio of 10:1, and then stirred at 300 rpm for 10 min; the mixture was placed in a 85°C water bath to reflux until completely dissolved; the solution was precipitated in excess acetone and anhydrous ethanol, respectively; the solution-precipitation operation was repeated for 3 times; and the solid was dried in a 60°C drying oven at a vacuum degree of 0.1 MPa to constant weight to obtain polylactic acid-maleic anhydride polymer;

[0034] (4) menthol, methyl jasmonate and ethanol were mixed at a mass ratio of 2:0.5:20 to obtain an oil phase solution; oxidized paraffin was heated to 60°C to melt, and then mixed with polysorbate 80, citric acid, deionized water at a mass ratio of 1:0.05:0.01:10 to form an aqueous phase solution; the aqueous phase solution was added to the oil phase solution, and then emulsified by an emulsifier at 2000 rpm for 30 min to form an oil-in-water emulsion; polylactic acid-maleic anhydride polymer was added at a mass ratio of 0.2:1, and then the mixture was stirred at 40°C and 200 rpm for 4 h; the reaction solution was filtered, and the filter cake was washed with deionized water for 2 times; and the filter cake was dried at 30°C for 12 h to obtain insect-resistant microcapsules with a particle size of 400 μm;

[0035] (5) 20 parts by weight of the composite microparticles, 20 parts by weight of the insect-resistant microcapsules, 10 parts by weight of potassium dihydrogen phosphate and 10 parts by weight of urea were mixed, and then mixed with deionized water at a mass ratio of 1:50 at room temperature to form a chemical fertilizer for foliar spraying.

[0036] Example 2

[0037] (1) Nanometer silicon dioxide with a particle size of 80 nm, sodium bicarbonate, calcium citrate and deionized water were mixed in a mass ratio of 7:2:1:50, stirred at 1000 rpm for 30 min, and then spray dried under the following conditions: inlet temperature of 150°C, gas pressure of 0.1 kg / cm, pump speed of 10 ml / min, and circulating air speed of 0.6 m / min to obtain composite microparticles with a particle size of 35 μm; 3 / min after spray drying;

[0038] (2) Horseradish peroxidase was mixed with phosphate buffer to prepare an enzyme activation solution with a concentration of 1 mg / ml and a pH of 6.5. Powdered paraffin with a particle size of 100 μm was mixed with the enzyme activation solution in a mass ratio of 1:0.2, stirred at 300 rpm for 10 min at 35°C, and then 30 wt% H2O2 aqueous solution with a mass 5 times that of the paraffin was added dropwise at a rate of 2 ml / min. After stirring and reacting for 10 h, the mixture was cooled to room temperature, petroleum ether with a mass 35 times that of the paraffin was added, stirred at 100 rpm for 10 min, and then centrifuged at 4000 rpm for 10 min to remove the precipitate. The supernatant was distilled at 55°C under a vacuum of -0.1 MPa for 1.5 h, and the solid was dried in an oven at 30°C to constant weight to obtain oxidized paraffin;

[0039] (3) Polylactic acid with a molecular weight of 800 was dried in a 60°C drying oven for 12 h, and then simultaneously added into a torque rheometer with maleic anhydride in a mass ratio of 20:1. The temperature was set to 180°C and the rotation speed was set to 60 rpm. After mixing for 2 min, 0.001 times the mass of the polylactic acid of dicumyl peroxide was added, and mixing was continued for 8 min. After cooling to room temperature, solid microparticles were obtained. The solid microparticles were added into dichloromethane with a mass 10 times that of the polylactic acid, stirred at 300 rpm for 10 min, and then placed in a 85°C water bath to reflux until completely dissolved. The solution was precipitated in excess acetone and anhydrous ethanol, respectively. The solution-precipitation operation was repeated 3 times. The solid was dried in a drying oven at 60°C under a vacuum of 0.1 MPa to constant weight to obtain a polylactic acid-maleic anhydride polymer;

[0040] (4) Menthol, methyl jasmonate and ethanol were mixed in a mass ratio of 3:0.1:20 to obtain an oil phase solution after stirring at 200 rpm for 10 min. Oxidized paraffin was melted by heating to 60°C, and then mixed with polysorbate 80, citric acid, deionized water in a mass ratio of 1:0.1:0.02:10 to form an aqueous phase solution after stirring at 200 rpm for 30 min. The aqueous phase solution was added into the oil phase solution, emulsified with an emulsifier at 2000 rpm for 30 min to form an oil-in-water emulsion. Oxidized paraffin with a mass 0.25 times that of the polylactic acid-maleic anhydride polymer was added, and the reaction was carried out at 40°C with stirring at 200 rpm for 4 h. The reaction solution was filtered, the filter cake was washed with deionized water 3 times, and then dried at 30°C for 12 h to obtain insect-resistant microcapsules with a particle size of 450 μm.

[0041] (5) 25 parts by weight of the composite microparticles, 25 parts by weight of the pest control microcapsules, 12 parts by weight of potassium dihydrogen phosphate, and 12 parts by weight of urea were mixed, and then mixed with deionized water at a mass ratio of 1:50 at room temperature and stirred at 150 rpm for 10 min to form a chemical fertilizer for foliar spraying.

[0042] Example 3

[0043] (1) Nanosilica with a particle size of 100 nm, sodium bicarbonate, calcium citrate, and deionized water were mixed at a mass ratio of 8:3:1:50, then stirred at 1000 rpm for 30 min, and then spray dried under the following conditions: inlet temperature of 150°C, gas pressure of 0.1 kg / cm, pump speed of 10 ml / min, and circulating air speed of 0.6 m / min to obtain composite microparticles with a particle size of 50 μm; 3

[0044] (2) Horseradish peroxidase was mixed with phosphate buffer to prepare an enzyme activation solution with a concentration of 1 mg / ml and a pH of 7; 100 μm powdered paraffin was mixed with the enzyme activation solution at a mass ratio of 1:0.3, then stirred at 40°C at 300 rpm for 10 min, 30 wt% H2O2 aqueous solution was added dropwise to the mixture at a rate of 2 ml / min, the stirring was maintained for 12 h, then the mixture was cooled to room temperature, petroleum ether was added at 40 times the mass of the paraffin, and the mixture was stirred at 100 rpm for 10 min, then centrifuged at 4000 rpm for 10 min to remove the precipitate, the supernatant was distilled at 60°C under a vacuum of -0.1 MPa for 2 h, and the solid was dried to constant weight in a 30°C oven to obtain oxidized paraffin;

[0045] (3) Polylactic acid with a molecular weight of 800 was dried in a 60°C drying oven for 12 h, then mixed with maleic anhydride at a mass ratio of 20:1 in a torque rheometer, the temperature was set to 180°C, the rotation speed was set to 60 rpm, and the mixture was mixed for 2 min, then 0.001 times the mass of the polylactic acid of dicumyl peroxide was added, and the mixture was mixed for another 8 min, then cooled to room temperature to obtain solid microparticles; the solid microparticles were added to 10 times the mass of the polylactic acid of dichloromethane, and the mixture was stirred at 300 rpm for 10 min, then placed in a 85°C water bath to reflux until completely dissolved, then precipitated in excess acetone and anhydrous ethanol, respectively, and the dissolution-precipitation operation was repeated 3 times, then the solid was placed in a 60°C drying oven under a vacuum of 0.1 MPa to dry to constant weight to obtain a polylactic acid-maleic anhydride polymer;

[0046] ​(4) mixed menthol, methyl jasmonate and ethanol in a mass ratio of 4:1.5:20 to obtain an oil phase solution, heated oxidized paraffin to 60°C to melt, mixed with polysorbate 80, citric acid, deionized water in a mass ratio of 1:0.15:0.03:10, stirred at 200 rpm for 30 min to form an aqueous phase solution, added the aqueous phase solution to the oil phase solution, emulsified with an emulsifier at 2000 rpm for 30 min to form an oil-in-water emulsion, added 0.3 times the mass of oxidized paraffin of polylactic acid-maleic anhydride polymer, stirred at 40°C and 200 rpm for 4 h, filtered the reaction solution, washed the filter cake with deionized water 4 times, and dried at 30°C for 12 h to obtain insect-resistant microcapsules with a particle size of 500 μm;

[0047] (5) mixed 30 parts by weight of the composite microparticles, 30 parts by weight of the insect-resistant microcapsules, 15 parts by weight of potassium dihydrogen phosphate, and 15 parts by weight of urea, mixed with deionized water in a mass ratio of 1:50 at room temperature and stirred at 150 rpm for 10 min to form a chemical fertilizer for foliar spraying.

[0048] Comparative Example 1

[0049] Comparative Example 1 differs from Example 2 in that step (1) is omitted, and step (5) is changed to: mixed 25 parts by weight of the insect-resistant microcapsules, 12 parts by weight of potassium dihydrogen phosphate, and 12 parts by weight of urea, mixed with deionized water in a mass ratio of 1:50 at room temperature and stirred at 150 rpm for 10 min to form a chemical fertilizer for foliar spraying, and the remaining steps are the same as in Example 2.

[0050] Comparative Example 2

[0051] Comparative Example 2 differs from Example 2 in that step (1) is different, and step (1) is changed to: mixed 80 nm particle size nanosilica, calcium citrate and deionized water in a mass ratio of 7:1:50, stirred at 1000 rpm for 30 min, and then spray dried under the following conditions: inlet temperature 150°C, gas pressure 0.1 kg / cm, pump speed 10 ml / min, and circulating air speed 0.6 m 3 / min to obtain composite microparticles with a particle size of 35 μm, and the remaining steps are the same as in Example 2.

[0052] Comparative Example 3

[0053] Comparative Example 3 differs from Example 2 in that step (1) is different, in that step (1) is changed to: nano-silica with a particle size of 80 nm, sodium bicarbonate and deionized water are mixed in a mass ratio of 7:2:50, then stirred at 1000 rpm for 30 min, and then spray dried under the following conditions: inlet temperature of 150°C, gas pressure of 0.1 kg / cm, pump speed of 10 ml / min, and circulating air speed of 0.6 m 3 / min to obtain composite microparticles with a particle size of 35 μm, and the remaining steps are the same as in Example 2.

[0054] Comparative Example 4

[0055] Comparative Example 4 differs from Example 2 in that step (4) is different, in that step (4) is changed to: methyl jasmonate and ethanol are mixed in a mass ratio of 0.1:20 to obtain an oil phase solution, heated oxidized paraffin to 60°C to melt, and then mixed with polysorbate 80, citric acid, deionized water in a mass ratio of 1:0.1:0.02:10 to form an aqueous phase solution, which is stirred at 200 rpm for 30 min; the aqueous phase solution is added to the oil phase solution, emulsified with an emulsifier at 2000 rpm for 30 min to form an oil-in-water emulsion, then 0.25 times the mass of the oxidized paraffin of polylactic acid-maleic anhydride polymer is added, and stirred at 40°C and 200 rpm for 4 h, then the reaction solution is suction filtered, the filter cake is washed with deionized water 3 times, and dried at 30°C for 12 h to obtain insect-resistant microcapsules with a particle size of 450 μm, and the remaining steps are the same as in Example 2.

[0056] Comparative Example 5

[0057] Comparative Example 5 differs from Example 2 in that step (4) is different, in that step (4) is changed to: menthol and ethanol are mixed in a mass ratio of 3:20 to obtain an oil phase solution, heated oxidized paraffin to 60°C to melt, and then mixed with polysorbate 80, citric acid, deionized water in a mass ratio of 1:0.1:0.02:10 to form an aqueous phase solution, which is stirred at 200 rpm for 30 min; the aqueous phase solution is added to the oil phase solution, emulsified with an emulsifier at 2000 rpm for 30 min to form an oil-in-water emulsion, then 0.25 times the mass of the oxidized paraffin of polylactic acid-maleic anhydride polymer is added, and stirred at 40°C and 200 rpm for 4 h, then the reaction solution is suction filtered, the filter cake is washed with deionized water 3 times, and dried at 30°C for 12 h to obtain insect-resistant microcapsules with a particle size of 450 μm, and the remaining steps are the same as in Example 2.

[0058] Comparative Example 6

[0059] Comparative Example 6 differs from Example 2 in that steps (2), (3), and (4) are omitted, and step (5) is changed to: 25 parts by weight of the composite microparticles, 12 parts by weight of potassium dihydrogen phosphate, and 12 parts by weight of urea are mixed, and then mixed with deionized water at room temperature at a mass ratio of 1:50 and stirred at 150 rpm for 10 min to form a chemical fertilizer for foliar spraying.

[0060] Comparative Example 7

[0061] Comparative Example 7 differs from Example 2 in that steps (1), (2), (3), and (4) are omitted, and step (5) is changed to: 12 parts by weight of potassium dihydrogen phosphate and 12 parts by weight of urea are mixed, and then mixed with deionized water at room temperature at a mass ratio of 1:50 and stirred at 150 rpm for 10 min to form a chemical fertilizer for foliar spraying.

[0062] Effect Example

[0063] The performance analysis results of the pest-resistant chemical fertilizers for vegetables using Examples 1 to 3 and Comparative Examples 1 to 7 of the present application are given in Table 1 below.

[0064] Table 1

[0065]

[0066]

[0067] From the experimental data comparison of the number of leaf damages of the examples and comparative examples, it can be found that the present application uses nanosilica as the main body of silicon fertilizer, and mixes the composite microparticles prepared by the spray drying technology of sodium bicarbonate and calcium citrate with the self-prepared pest-resistant microcapsules with pH response, and sprays them on the leaves of vegetables, so that in the process of feeding, the acidic substances in the oral saliva react with sodium bicarbonate and calcium citrate to increase the local pH value, promote the rupture of the pest-resistant microcapsules with pH response, and quickly release the effective ingredients to directly act on the oral cavity and digestive tract of the pests, inhibit the feeding and physiological activities of the pests, and at the same time, the vegetables themselves activate the defense mechanism to achieve precise response to the feeding behavior of the pests. From the experimental data comparison of the release rates of the examples and comparative examples, it can be found that the self-prepared pest-resistant microcapsules with pH response in the present application can not only rupture and quickly release the core materials in weak alkaline environment, but also release the core materials slowly in daily process, achieving the long-acting effect of imitating pest damage.

[0068] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference herein to any prior art is to be taken as an admission that the present application is not entitled to antedate such prior art by virtue of prior application. Any reference to the term "comprising" is to be construed in accordance with the definition of that term provided in the preamble to Article 69 of the European Patent Convention. Any reference to the term "comprising" is to be construed in accordance with the definition of that term provided in the preamble to Article 69 of the European Patent Convention.

Claims

1. A method for preparing a pesticide-resistant fertilizer for vegetables, characterized in that, 20-30 parts of the composite microparticles, 20-30 parts of the pest control microcapsules, 10-15 parts of potassium dihydrogen phosphate and 10-15 parts of urea by weight; The preparation method of the composite microparticles is as follows: nanosilica, sodium bicarbonate, calcium citrate and deionized water are mixed in a mass ratio of 6-8:1-3:1:50, then stirred at 1000 rpm for 30 min, and then spray dried to obtain the composite microparticles with a particle size of 20-50 μm; The preparation method of the pest control microcapsules is as follows: (1) a biological enzyme is mixed with a buffer solution to prepare an enzyme activation solution with a concentration of 1 mg / ml and a pH of 6-7; a powdered paraffin is mixed with the enzyme activation solution in a mass ratio of 1:0.1-0.3, then stirred at 300 rpm for 10 min at 30-40°C, then an oxidizing agent is added to the mixture at a rate of 2 ml / min, the stirring is continued for 8-12 h, then the mixture is cooled to room temperature, an organic solvent is added to the mixture at 30-40 times the mass of the paraffin, then stirred at 100 rpm for 10 min, then centrifuged at 4000 rpm for 10 min, the supernatant is distilled at 50-60°C and a vacuum degree of -0.1 MPa for 1-2 h, and the solid is dried in an oven at 30°C for 12 h to obtain oxidized paraffin; (2) a terpenoid compound, methyl jasmonate and ethanol are mixed in a mass ratio of 2-4:0.5-1.5:20 to obtain an oil phase solution; the oxidized paraffin is heated to 60°C to melt, then mixed with a surfactant, a crosslinking agent, deionized water in a mass ratio of 1:0.05-0.15:0.01-0.03:10, and stirred at 200 rpm for 30 min to form an aqueous phase solution; The aqueous phase solution is added to the oil phase solution, emulsified at 2000 rpm for 30 min by using an emulsifier to form an oil-in-water emulsion, then a polylactic acid-maleic anhydride polymer is added at 0.2-0.3 times the mass of the oxidized paraffin, and the reaction is carried out at 40°C and 200 rpm for 4 h, then the reaction solution is filtered, the filter cake is washed with deionized water for 2-4 times, and dried at 30°C for 12 h to obtain the pest control microcapsules with a particle size of 400-500 μm.

2. The method of claim 1, wherein the insect-resistant vegetable chemical fertilizer is prepared by adding 0.1-0.5% of the insecticide to 100 parts of the chemical fertilizer. In step (1), the nanosilica has a particle size of 50-100 nm.

3. The method of claim 1, wherein the insect-resistant vegetable chemical fertilizer is prepared by adding 0.1-0.3% of the insecticide to 100 parts of the chemical fertilizer. In step (2), the biological enzyme is horseradish peroxidase.

4. The method for preparing the chemical fertilizer for preventing insect damage to vegetables according to claim 1, characterized in that, In step (2), the buffer solution is a phosphate buffer solution.

5. The method of claim 1, wherein the insect-resistant chemical fertilizer for vegetables is prepared by adding 0.1-0.3% of the insecticide to 100 parts of the chemical fertilizer. In step (2), the oxidizing agent is a 30 wt% H2O2 aqueous solution.

6. The method of claim 1, wherein the insect-resistant chemical fertilizer for vegetables is prepared by adding 0.1-0.3% of the insecticide to 100 parts of the chemical fertilizer. In step (2), the organic solvent is petroleum ether.

7. The method of claim 1, wherein the insect-resistant chemical fertilizer for vegetables is prepared by adding 0.1-0.3% of the insecticide to 100 parts of the chemical fertilizer. In step (3), the terpenoid compound is at least one of menthol, limonene, artemisinin, xianglongtian and azadirachtin.

8. The method of claim 1, wherein the insect-resistant chemical fertilizer for vegetables is prepared by adding 0.1-0.3% of the insecticide to 100 parts of the chemical fertilizer. In step (3), the surfactant is polysorbate 80.

9. The method of claim 1, wherein the insect-resistant chemical fertilizer for vegetables is prepared by adding 0.1-0.3% of the insecticide to 100 parts of the chemical fertilizer. In step (3), the crosslinking agent is citric acid.

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