Rice field organic herbicide capable of enabling rice to be rich in selenium and preparation process of rice field organic herbicide

Abstract

The invention provides a rice field organic herbicide capable of enriching rice with selenium and a preparation process of the rice field organic herbicide, and belongs to the technical field of herbicides. The preparation process comprises the following steps: preparing a composite carrier material; loading organic selenium-enriched amino acid; preparing a magnetic composite filler; preparing magnetic gel coated powder; and preparing the organic herbicide. The organic herbicide disclosed by the invention is prepared and used at present, after the organic herbicide is uniformly sprayed in a rice field, young weeds can be inhibited from growing until withering in an oxygen-deficient and light-deficient environment, so that a weeding effect is achieved, manpower and material resources are saved, meanwhile, the organic herbicide can release organic selenium-enriched amino acid in field water, and the yield of the seedlings is increased within 10-14 days of full-water weed control after rice transplanting. Selenium elements in the organic selenium-rich amino acids are absorbed by seedling plants and converted into rice, and selenium-rich rice is produced.

Description

Technical Field

[0001] The invention relates to the technical field of herbicides, and in particular to an organic herbicide for paddy fields capable of enriching rice with selenium and a preparation process thereof. Background Art

[0002] In current agricultural production, the problem of weeds in rice fields has always been one of the major problems that troubles farmers. Weeds compete with rice for nutrients, water, sunlight and space, seriously affecting the growth and yield of rice. Therefore, reasonable and effective weed control is extremely important to ensure rice production.

[0003] As for organic rice, which is one of the rice varieties, it strictly follows the standards of organic agriculture during the planting process, does not use chemically synthesized pesticides, fertilizers, plant growth regulators and other substances, but adopts natural farming methods and ecological management measures to ensure the healthy growth of crops. Therefore, at present, manual weeding, mechanical weeding and biological weeding are generally used for weed control in organic rice cultivation. However, manual weeding and mechanical weeding have limited effects and consume high labor costs, while biological weeding methods are greatly affected by the environment and have strong weed selectivity, resulting in limited weed control effects; in addition, selenium-enriched rice, as a nutritionally fortified rice, is currently mainly achieved by spraying selenium fertilizers in the late stage of rice growth or adding selenium compounds to the soil. However, these methods have problems such as low selenium absorption and utilization rate, uneven selenium distribution, and possible soil selenium pollution due to excessive selenium application.

[0004] Therefore, it is necessary to propose an organic herbicide for paddy fields that can enrich rice with selenium and a preparation process thereof to save manpower and material resources. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide an organic herbicide for paddy fields that can enrich rice with selenium and a preparation process thereof.

[0006] A preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium comprises the following steps:

[0007] S1: Preparation of composite support materials

[0008] A zinc nitrate solution and a 2-methylimidazole solution are prepared respectively, and then the zinc nitrate solution is added to the 2-methylimidazole solution to prepare a carrier powder, and after surface alkalization modification, the carrier powder is added to a mixed solution prepared by disodium hydrogen phosphate, calcium chloride, Tris-HCl buffer and deionized water, and heated to react to obtain a composite carrier powder;

[0009] S2: Loaded with organic selenium-rich amino acids

[0010] The organic selenium-rich amino acid is fully dissolved in deionized water at a solid-liquid ratio of 1g: (20-30) mL, and then the composite carrier material is added at a solid-liquid ratio of 1g: (35-45) mL, and ultrasonic loading is performed for 1-2 hours, and then centrifugation, washing and drying are performed to obtain amino acid-loaded powder;

[0011] S3: Preparation of magnetic composite fillers

[0012] Illite powder is suspended in deionized water, and then ferric chloride and ferrous chloride are added, and after ultrasonic treatment, potassium hydroxide and urea are added to react to obtain a magnetic composite filler;

[0013] S4: Preparation of magnetic gel-coated powder

[0014] The magnetic composite filler is uniformly dispersed in deionized water, and then mixed with chitosan, carboxymethyl cellulose and sodium hyaluronate to prepare chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution respectively, and then the three are mixed and added with the amino acid powder and epichlorohydrin to react to prepare a composite gel, which is freeze-dried and ground to obtain a magnetic gel-coated powder;

[0015] S5: Formulating organic herbicides

[0016] The food-grade detergent is mixed with sunflower oil to prepare an emulsifier, and benzoic acid and seaweed essence are dissolved in water to prepare a mixed solution. The silicone oil, the emulsifier and the mixed solution are then mixed and then mixed with the magnetic gel-coated powder to obtain an organic herbicide.

[0017] Furthermore, S1 specifically includes the following steps:

[0018] S1.1: Add zinc nitrate hexahydrate and 2-methylimidazole into deionized water at a solid-liquid ratio of 1 g: (20-30) mL, stir to dissolve, and ultrasonicate for 5-10 min to obtain zinc nitrate solution and 2-methylimidazole solution;

[0019] S1.2: Stirring the 2-methylimidazole solution at a rate of 400-500 r / min, then adding an equal volume of the zinc nitrate solution while stirring, continuing stirring for 4-5 hours, standing and aging for 2-3 hours, centrifuging, washing, drying and grinding to obtain a carrier powder;

[0020] S1.3: Add the above carrier powder to 3 mol / L sodium hydroxide solution at a solid-liquid ratio of 1 g: (10-12) mL, heat and stir at 50-60 ° C for 1.5-2.5 h to perform surface alkalization modification, then filter, wash to neutrality and dry to obtain alkali-modified carrier powder;

[0021] S1.4: Dissolve disodium hydrogen phosphate in deionized water at a solid-liquid ratio of 1 g: (35-45) mL, then add calcium chloride, stir thoroughly to dissolve, add Tris-HCl buffer to adjust the pH to 7-8, and obtain a mixed solution, wherein the mass ratio of calcium chloride to disodium hydrogen phosphate is (1.8-2.2): 1;

[0022] S1.5: Add the above-mentioned alkali-modified carrier powder to the above-mentioned mixed solution at a solid-liquid ratio of 1g: (8-10)mL, stir and disperse thoroughly, and then transfer to a hydrothermal reactor, heat and react at 100-120℃ for 4-5h, cool naturally to room temperature, filter, wash and dry to obtain a composite carrier material.

[0023] Furthermore, S3 specifically includes the following steps:

[0024] S3.1: Add illite powder into deionized water at a solid-liquid ratio of 1 g: (80-90) mL, and ultrasonicate for 1-2 h to obtain an illite suspension;

[0025] S3.2: Add ferric chloride and ferrous chloride to the above illite suspension in a mass ratio of (1.4-1.6):1, stir and mix evenly, and then ultrasonically treat for 1-2 hours, then add potassium hydroxide and urea in a mass ratio of (1.3-1.5):1, stir and react for 10-12 hours under a nitrogen atmosphere, and obtain a magnetic composite filler after filtering, freeze drying and grinding.

[0026] Furthermore, S4 specifically includes the following steps:

[0027] S4.1: Disperse the magnetic composite filler prepared in step S3.2 uniformly in deionized water at a solid-liquid ratio of 1 g: (70-80) mL to obtain a magnetic composite filler suspension;

[0028] S4.2: chitosan, carboxymethyl cellulose and sodium hyaluronate are added to the magnetic composite filler suspension at a solid-liquid ratio of 1 g: (40-50) mL, respectively, and after uniform dispersion, a chitosan mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution are obtained;

[0029] S4.3: Mix equal masses of the chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution, and then add the amino acid powder prepared in step S2 at a solid-liquid ratio of 1 g: (150-160) mL, ultrasonically treat for 20-30 min, add epichlorohydrin, stir to react for 2-3 h, and then stand for 1-2 h to obtain a composite gel, wherein the mass ratio of epichlorohydrin to chitosan is 1: (30-40);

[0030] S4.4: Place the above composite gel in a freeze dryer for freeze drying, and grind to obtain magnetic gel-coated powder.

[0031] Furthermore, S5 specifically includes the following steps:

[0032] S5.1: Add food-grade detergent to sunflower oil in a volume ratio of 1:(2.8-3.2), stir and mix thoroughly to obtain an emulsifier;

[0033] S5.2: Add benzoic acid and seaweed extract into water at a solid-liquid ratio of 1 g: (0.1-0.3) g: (9-11) mL, stir thoroughly to dissolve, and obtain a mixed solution;

[0034] S5.3: Stir and mix the silicone oil, the emulsifier and the mixed solution in a volume ratio of 1: (3.8-4): (4-4.2) to obtain an organic herbicide. Then add the magnetic gel-coated powder obtained in step S4.4, and continue stirring and mixing to obtain the organic herbicide.

[0035] Furthermore, the solid-liquid ratio of the total mass of ferric chloride and ferrous chloride to the illite suspension is 1 g:(18-20) mL, and the mass ratio of potassium hydroxide to ferric chloride is 1:(12-13).

[0036] Furthermore, the solid-liquid ratio of the magnetic gel-coated powder to the mixed solution is 1 g: (200-220) mL.

[0037] Furthermore, an organic herbicide for paddy fields capable of enriching rice with selenium is prepared by the preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium as described in any one of the above items.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The organic herbicide of the present invention is ready to use. It is prepared by mixing a food-grade detergent with sunflower oil to prepare an emulsifier, then mixing benzoic acid, seaweed essence and dehydrated water to prepare a mixed solution, and then mixing silicone oil, emulsifier, mixed solution and magnetic gel-coated powder to prepare an organic herbicide. After the organic herbicide is evenly sprayed in the rice field, it can disperse on the surface of the field water to form a complete dark brown film, effectively isolating the oxygen supply of young weeds, and the dark brown color can block sunlight from penetrating into the water, so that the young weeds are inhibited from growing until they wither in an oxygen-deficient and light-deficient environment, thereby achieving a weed control effect and saving manpower and material resources. At the same time, the magnetic gel-coated powder releases organic selenium-rich amino acids in the field water. During the 10-14 days of full water control of weeds after transplanting, the selenium element in the organic selenium-rich amino acids is absorbed by the rice seedlings and converted into rice to produce selenium-rich rice.

[0040] 2. The present invention prepares carrier powder by first using zinc nitrate hexahydrate and 2-methylimidazole as raw materials, and then uses sodium hydroxide solution to perform surface alkalization modification on the carrier powder, and then dissolves disodium hydrogen phosphate and calcium chloride in deionized water, and adds the carrier powder after surface alkalization modification to perform hydrothermal reaction, so as to achieve secondary modification of the surface of the carrier powder to prepare a composite carrier powder. After the composite carrier powder is used to load the organic selenium-rich amino acid, the stability of the organic selenium-rich amino acid can be effectively improved, and after two surface modifications, the loading active sites of the loaded powder can be increased, thereby significantly improving the loading rate of the carrier powder for the organic selenium-rich amino acid, so as to improve the selenium-enriched effect of rice.

[0041] 3. The present invention prepares illite powder into a suspension, and adds ferric chloride, ferrous chloride, potassium hydroxide and urea to react to prepare a magnetic composite filler, and then suspends the magnetic composite filler in deionized water, and mixes it with chitosan, carboxymethyl cellulose and sodium hyaluronate to prepare a chitosan mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution respectively, and then mixes the chitosan mixed solution, the carboxymethyl cellulose mixed solution and the sodium hyaluronate mixed solution with amino acid powder, and cross-links them into a composite gel using epichlorohydrin as a cross-linking agent to achieve coating of the amino acid powder to form a magnetic gel-coated powder. Since the magnetic composite filler can generate hydrogen bonds and electrostatic interactions with the gel molecular chains and is bound in the gel molecular network, the gel coated on the surface of the amino acid powder has excellent magnetic response performance. When the organic selenium-rich amino acid in the amino acid powder is released, the composite carrier powder can be recovered by applying an external magnetic field to reduce pollution to the paddy field environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0043] Figure 1 The present invention is a flow chart of the preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium, which is used in an embodiment of the present invention.

[0044] Figure 2 This is a schematic diagram of a film formed on the water surface of a field after the organic herbicide prepared in Example 1 of the present invention is sprayed.

[0045] Figure 3 This is a schematic diagram of the growth of weeds in the field 10 days after the organic herbicide prepared in Example 1 of the present invention was sprayed. DETAILED DESCRIPTION

[0046] In the following, in conjunction with specific embodiments, an organic herbicide for paddy fields capable of enriching rice with selenium and a preparation process thereof provided by the present invention are described in detail. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies.

[0047] Example 1

[0048] A preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium, such as Figure 1 As shown, the following steps are included:

[0049] S1: Preparation of composite support materials

[0050] S1.1: Add zinc nitrate hexahydrate and 2-methylimidazole into deionized water at a solid-liquid ratio of 1 g:20 mL, stir to dissolve, and ultrasonicate for 5 min to obtain zinc nitrate solution and 2-methylimidazole solution;

[0051] S1.2: Stir the 2-methylimidazole solution at a rate of 400 r / min, then add an equal volume of the zinc nitrate solution while stirring, continue stirring for 4 hours, let stand for aging for 2 hours, centrifuge, wash, dry and grind to obtain a carrier powder;

[0052] S1.3: Add the above carrier powder to 3 mol / L sodium hydroxide solution at a solid-liquid ratio of 1 g:10 mL, heat and stir at 50-60 ° C for 1.5 h to perform surface alkalization modification, then filter, wash to neutrality and dry to obtain alkali-modified carrier powder;

[0053] S1.4: Dissolve disodium hydrogen phosphate in deionized water at a solid-liquid ratio of 1 g:35 mL, then add calcium chloride, stir thoroughly to dissolve, add Tris-HCl buffer to adjust the pH to 7, and obtain a mixed solution in which the mass ratio of calcium chloride to disodium hydrogen phosphate is 1.8:1;

[0054] S1.5: Add the above-mentioned alkali-modified carrier powder to the above-mentioned mixed solution at a solid-liquid ratio of 1g:8mL, stir and disperse thoroughly, transfer to a hydrothermal reactor, heat and react at 100°C for 4h, cool naturally to room temperature, filter, wash and dry to obtain a composite carrier material;

[0055] S2: Loaded with organic selenium-rich amino acids

[0056] The organic selenium-rich amino acid was fully dissolved in deionized water at a solid-liquid ratio of 1g:20mL, and then the composite carrier material was added at a solid-liquid ratio of 1g:35mL, and ultrasonic loading was performed for 1h, followed by centrifugal separation, washing and drying to obtain amino acid-loaded powder;

[0057] S3: Preparation of magnetic composite fillers

[0058] S3.1: Add illite powder to deionized water at a solid-liquid ratio of 1g:80mL, and ultrasonically treat for 1-2h to obtain an illite suspension;

[0059] S3.2: Add ferric chloride and ferrous chloride to the illite suspension at a mass ratio of 1.4:1, stir and mix evenly, and then ultrasonicate for 1 hour, then add potassium hydroxide and urea at a mass ratio of 1.3:1, stir and react for 10 hours under a nitrogen atmosphere, filter, freeze-dry and grind to obtain a magnetic composite filler, wherein the total mass of ferric chloride and ferrous chloride and the solid-liquid ratio of the illite suspension is 1g:18mL, and the mass ratio of potassium hydroxide to ferric chloride is 1:12;

[0060] S4: Preparation of magnetic gel-coated powder

[0061] S4.1: Disperse the magnetic composite filler prepared in step S3.2 uniformly in deionized water at a solid-liquid ratio of 1 g:70 mL to obtain a magnetic composite filler suspension;

[0062] S4.2: chitosan, carboxymethyl cellulose and sodium hyaluronate are added to the magnetic composite filler suspension at a solid-liquid ratio of 1 g:40 mL, respectively, and after uniform dispersion, a chitosan mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution are obtained;

[0063] S4.3: Mix equal masses of the chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution, and then add the amino acid powder prepared in step S2 at a solid-liquid ratio of 1 g:150 mL, ultrasonically treat for 20 min, add epichlorohydrin, stir to react for 2 h, and then stand for 1 h to obtain a composite gel, wherein the mass ratio of epichlorohydrin to chitosan is 1:30;

[0064] S4.4: placing the composite gel in a freeze dryer for freeze drying, and grinding to obtain magnetic gel coated powder;

[0065] S5: Formulating organic herbicides

[0066] S5.1: adding food-grade detergent to sunflower oil in a volume ratio of 1:2.8, stirring and mixing thoroughly to obtain an emulsifier;

[0067] S5.2: Add benzoic acid and seaweed extract into water at a solid-liquid ratio of 1 g:0.1 g:9 mL, stir thoroughly to dissolve, and obtain a mixed solution;

[0068] S5.3: Stir and mix the silicone oil, the emulsifier and the mixed solution in a volume ratio of 1:3.8:4, then add the magnetic gel-coated powder obtained in step S4.4, continue stirring and mixing to obtain an organic herbicide, wherein the solid-liquid ratio of the magnetic gel-coated powder to the mixed solution is 1g:200mL.

[0069] Example 2

[0070] A preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium, such as Figure 1 As shown, the following steps are included:

[0071] S1: Preparation of composite support materials

[0072] S1.1: Add zinc nitrate hexahydrate and 2-methylimidazole into deionized water at a solid-liquid ratio of 1 g:25 mL, stir to dissolve, and ultrasonicate for 7 min to obtain zinc nitrate solution and 2-methylimidazole solution;

[0073] S1.2: Stir the 2-methylimidazole solution at a rate of 450 r / min, then add an equal volume of the zinc nitrate solution while stirring, continue stirring for 4.5 hours, let stand for aging for 2.5 hours, centrifuge, wash, dry and grind to obtain a carrier powder;

[0074] S1.3: Add the above carrier powder to 3 mol / L sodium hydroxide solution at a solid-liquid ratio of 1 g:11 mL, heat and stir at 55 ° C for 2 h to perform surface alkalization modification, then filter, wash to neutrality and dry to obtain alkali-modified carrier powder;

[0075] S1.4: Dissolve disodium hydrogen phosphate in deionized water at a solid-liquid ratio of 1 g:40 mL, then add calcium chloride, stir thoroughly to dissolve, add Tris-HCl buffer to adjust the pH to 7.5, and obtain a mixed solution in which the mass ratio of calcium chloride to disodium hydrogen phosphate is 2:1;

[0076] S1.5: Add the above-mentioned alkali-modified carrier powder to the above-mentioned mixed solution at a solid-liquid ratio of 1g:9mL, stir and disperse thoroughly, transfer to a hydrothermal reactor, heat and react at 110°C for 4.5h, cool naturally to room temperature, filter, wash and dry to obtain a composite carrier material;

[0077] S2: Loaded with organic selenium-rich amino acids

[0078] The organic selenium-rich amino acid was fully dissolved in deionized water at a solid-liquid ratio of 1g:25mL, and then the composite carrier material was added at a solid-liquid ratio of 1g:40mL, and ultrasonic loading was performed for 1.5h, and then centrifuged, washed and dried to obtain amino acid-loaded powder;

[0079] S3: Preparation of magnetic composite fillers

[0080] S3.1: Add illite powder to deionized water at a solid-liquid ratio of 1 g:85 mL, and ultrasonically treat for 1.5 h to obtain an illite suspension;

[0081] S3.2: Add ferric chloride and ferrous chloride to the illite suspension at a mass ratio of 1.5:1, stir and mix evenly, and then ultrasonicate for 1.5 hours, then add potassium hydroxide and urea at a mass ratio of 1.4:1, stir and react for 11 hours under a nitrogen atmosphere, filter, freeze-dry and grind to obtain a magnetic composite filler, wherein the total mass of ferric chloride and ferrous chloride and the solid-liquid ratio of the illite suspension is 1g:19mL, and the mass ratio of potassium hydroxide to ferric chloride is 1:12.5;

[0082] S4: Preparation of magnetic gel-coated powder

[0083] S4.1: Disperse the magnetic composite filler obtained in step S3.2 uniformly in deionized water at a solid-liquid ratio of 1 g:75 mL to obtain a magnetic composite filler suspension;

[0084] S4.2: chitosan, carboxymethyl cellulose and sodium hyaluronate are added to the magnetic composite filler suspension at a solid-liquid ratio of 1 g:45 mL, respectively, and after uniform dispersion, a chitosan mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution are obtained;

[0085] S4.3: Mix equal masses of the chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution, and then add the amino acid powder prepared in step S2 at a solid-liquid ratio of 1 g:155 mL, ultrasonically treat for 25 min, add epichlorohydrin, stir to react for 2.5 h, and then stand for 1.5 h to obtain a composite gel, wherein the mass ratio of epichlorohydrin to chitosan is 1:35;

[0086] S4.4: placing the composite gel in a freeze dryer for freeze drying, and grinding to obtain magnetic gel coated powder;

[0087] S5: Formulating organic herbicides

[0088] S5.1: Add food-grade detergent to sunflower oil in a volume ratio of 1:3, and stir well to obtain an emulsifier;

[0089] S5.2: Add benzoic acid and seaweed extract into water at a solid-liquid ratio of 1 g:0.2 g:10 mL, stir thoroughly to dissolve, and obtain a mixed solution;

[0090] S5.3: Stir and mix the silicone oil, the above-mentioned emulsifier and the above-mentioned mixed solution in a volume ratio of 1:3.9:4.1, then add the magnetic gel-coated powder obtained in step S4.4, continue stirring and mixing to obtain an organic herbicide, wherein the solid-liquid ratio of the magnetic gel-coated powder to the mixed solution is 1g:210mL.

[0091] Example 3

[0092] A preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium, such as Figure 1 As shown, the following steps are included:

[0093] S1: Preparation of composite support materials

[0094] S1.1: Add zinc nitrate hexahydrate and 2-methylimidazole into deionized water at a solid-liquid ratio of 1 g:30 mL, stir to dissolve, and perform ultrasonic treatment for 10 min to obtain a zinc nitrate solution and a 2-methylimidazole solution;

[0095] S1.2: Stir the 2-methylimidazole solution at a rate of 500 r / min, then add an equal volume of the zinc nitrate solution while stirring, continue stirring for 5 hours, let stand for aging for 3 hours, centrifuge, wash, dry and grind to obtain a carrier powder;

[0096] S1.3: Add the above carrier powder to 3 mol / L sodium hydroxide solution at a solid-liquid ratio of 1 g:12 mL, heat and stir at 60 ° C for 2.5 h to perform surface alkalization modification, then filter, wash to neutrality and dry to obtain alkali-modified carrier powder;

[0097] S1.4: Dissolve disodium hydrogen phosphate in deionized water at a solid-liquid ratio of 1 g:45 mL, then add calcium chloride, stir thoroughly to dissolve, add Tris-HCl buffer to adjust the pH to 8, and obtain a mixed solution in which the mass ratio of calcium chloride to disodium hydrogen phosphate is 2.2:1;

[0098] S1.5: Add the above-mentioned alkali-modified carrier powder to the above-mentioned mixed solution at a solid-liquid ratio of 1g:10mL, stir and disperse thoroughly, transfer to a hydrothermal reactor, heat and react at 120°C for 5h, cool naturally to room temperature, filter, wash and dry to obtain a composite carrier material;

[0099] S2: Loaded with organic selenium-rich amino acids

[0100] The organic selenium-rich amino acid was fully dissolved in deionized water at a solid-liquid ratio of 1g:30mL, and then the composite carrier material was added at a solid-liquid ratio of 1g:45mL, and ultrasonic loading was performed for 2h, followed by centrifugal separation, washing and drying to obtain amino acid-loaded powder;

[0101] S3: Preparation of magnetic composite fillers

[0102] S3.1: Add illite powder to deionized water at a solid-liquid ratio of 1 g:90 mL, and ultrasonically treat for 2 h to obtain an illite suspension;

[0103] S3.2: Add ferric chloride and ferrous chloride to the illite suspension at a mass ratio of 1.6:1, stir and mix evenly, and then ultrasonicate for 2 hours, then add potassium hydroxide and urea at a mass ratio of 1.5:1, stir and react for 12 hours under a nitrogen atmosphere, filter, freeze-dry and grind to obtain a magnetic composite filler, wherein the solid-liquid ratio of the total mass of ferric chloride and ferrous chloride to the illite suspension is 1g:20mL, and the mass ratio of potassium hydroxide to ferric chloride is 1:13;

[0104] S4: Preparation of magnetic gel-coated powder

[0105] S4.1: Disperse the magnetic composite filler prepared in step S3.2 uniformly in deionized water at a solid-liquid ratio of 1 g:80 mL to obtain a magnetic composite filler suspension;

[0106] S4.2: chitosan, carboxymethyl cellulose and sodium hyaluronate are added to the magnetic composite filler suspension at a solid-liquid ratio of 1 g:50 mL, respectively, and after uniform dispersion, a chitosan mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution are obtained;

[0107] S4.3: Mix equal masses of the chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution, and then add the amino acid powder prepared in step S2 at a solid-liquid ratio of 1 g:160 mL, ultrasonically treat for 30 min, add epichlorohydrin, stir to react for 3 h, and then stand for 2 h to obtain a composite gel, wherein the mass ratio of epichlorohydrin to chitosan is 1:40;

[0108] S4.4: placing the composite gel in a freeze dryer for freeze drying, and grinding to obtain magnetic gel coated powder;

[0109] S5: Formulating organic herbicides

[0110] S5.1: Add food-grade detergent to sunflower oil in a volume ratio of 1:3.2, and stir well to obtain an emulsifier;

[0111] S5.2: Add benzoic acid and seaweed extract into water at a solid-liquid ratio of 1 g:0.3 g:11 mL, stir thoroughly to dissolve, and obtain a mixed solution;

[0112] S5.3: Stir and mix the silicone oil, the emulsifier and the mixed solution in a volume ratio of 1:4:4.2, add the magnetic gel-coated powder obtained in step S4.4, continue stirring and mixing to obtain an organic herbicide, wherein the solid-liquid ratio of the magnetic gel-coated powder to the mixed solution is 1g:220mL.

[0113] Comparative Example 1

[0114] The difference between Comparative Example 1 and Example 1 is that steps S1.3-1.5 are removed, that is, the organic selenium-rich amino acid is directly loaded with the carrier powder.

[0115] Test example

[0116] Test 1: 3-5 days after transplanting in an organic rice field, when weeds in the field are still in the initial germination period of 0.5-1.0 leaf age, the field is backwatered to cover the entire field soil surface, and the field water level is higher than the top of the initial germination weed plant, so that it is completely submerged in water. The organic herbicide prepared in Example 1 is sprayed at 15 liters / mu. After the spraying is completed, a film is formed on the field water surface. Figure 2 As shown, after 10 days, the growth of weeds in the field was observed. Figure 3 As shown, rice and algae grow normally, and all underwater weeds wither. It can be seen that by first mixing food-grade detergent with sunflower oil to make an emulsifier, then mixing benzoic acid, seaweed essence and dehydrated water to make a mixed solution, and then mixing silicone oil, emulsifier, mixed solution and magnetic gel-coated powder to make an organic herbicide, after the organic herbicide is evenly sprayed on the rice field, it can disperse on the surface of the field water to form a complete dark brown film, effectively isolating the oxygen supply of young weeds, and the dark brown color can block sunlight from penetrating into the water, so that the young weeds are inhibited from growing until they wither in an oxygen-deficient and light-deficient environment, thereby achieving a weed control effect and saving manpower and material resources.

[0117] Test 2:

[0118] The mass concentration of the organic selenium-rich amino acid in the filtrate after centrifugation in step S2 of Examples 1-3 and Comparative Example 1 was detected by high performance liquid chromatography, and the loading rate was calculated as follows:

[0119] R(%)=[(m 0 -C e ×V e ) / m 0 ]×100%;

[0120] Where R is the load factor, C e is the mass concentration of organic selenium-rich amino acids in the filtrate, V e is the volume of the filtrate, m 0 is the initial mass of organic selenium-rich amino acid. The results are shown in Table 1.

[0121] Table 1: Comparison of the load rate results of Examples 1-3 and Comparative Example 1

[0122] Example 1 Example 2 Example 3 Comparative Example 1 Load factor (%) 26.46 26.53 26.55 17.93

[0123] As can be seen from Table 1, in Comparative Example 1, the carrier powder is not modified and is directly used to load organic selenium-rich amino acids. The loading rate of the organic selenium-rich amino acids is about 17.93%, which is less than that of Example 1. It can be seen that the surface of the carrier powder is modified by alkalization using sodium hydroxide solution, and then disodium hydrogen phosphate and calcium chloride are dissolved in deionized water, and the surface alkalized carrier powder is added for hydrothermal reaction to achieve secondary modification of the surface of the carrier powder to prepare a composite carrier powder. After the organic selenium-rich amino acids are loaded with the composite carrier powder, the stability of the organic selenium-rich amino acids can be effectively improved. After two surface modifications, the loading active sites of the loaded powder can be increased, thereby significantly improving the loading rate of the carrier powder for the organic selenium-rich amino acids, so as to improve the selenium-enriching effect of rice.

[0124] Experiment 3: Determination of pure Fe using a comprehensive physical property measurement system vibrating magnetometer 3 O 4 The saturation magnetic intensity of the magnetic gel-coated powders prepared in Examples 1-3 is shown in Table 2.

[0125] Table 2: Magnetic gel-coated powders prepared in Examples 1-3 and pure Fe 3 O 4 Saturation magnetic intensity comparison table

[0126] Example 1 Example 2 Example 3 <![CDATA[Pure Fe 3 O 4 > Saturation magnetic intensity (emu / g) 17.52 17.57 17.58 81.84

[0127] Experiment 4: 10 days after the organic herbicide prepared in Examples 1-3 was sprayed in the field, the magnetic gel-coated powder was recovered by applying an external magnetic field and the recovery rate was calculated. The results are shown in Table 3.

[0128] Table 3: Comparative table of recovery rates of magnetic gel-coated powders of organic herbicides prepared in Examples 1-3

[0129] Example 1 Example 2 Example 3 Recovery rate (%) 86.62 86.65 86.71

[0130] It can be seen from Table 2 that the saturation magnetic intensity of the magnetic gel-coated powders prepared in Examples 1-3 is approximately 3 O 4The magnetic responsiveness of the magnetic gel-coated powders was 21%, indicating that the magnetic responsiveness was good. In addition, it can be seen from Table 3 that the recovery rates of the magnetic gel-coated powders prepared in Examples 1-3 were approximately 86.62%, 86.65% and 86.71%, respectively. It can be seen that the magnetic composite filler is prepared by first preparing the illite powder into a suspension, and adding ferric chloride, ferrous chloride, potassium hydroxide and urea to react to prepare the magnetic composite filler, and then suspending the magnetic composite filler in deionized water, respectively mixing with chitosan, carboxymethyl cellulose and sodium hyaluronate to prepare chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution, and then mixing the chitosan into a suspension. A polysaccharide mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution are mixed with amino acid powder, and are cross-linked into a composite gel using epichlorohydrin as a cross-linking agent to achieve coating of the amino acid powder to form a magnetic gel-coated powder. The magnetic composite filler can generate hydrogen bonds and electrostatic interactions with the gel molecular chains and be bound in the gel molecular network, so that the gel coated on the surface of the amino acid powder has excellent magnetic response performance. When the organic selenium-rich amino acid in the amino acid powder is released, the composite carrier powder can be recovered by applying an external magnetic field to reduce pollution to the paddy field environment.

[0131] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium, characterized in that: The steps include: S1: Preparation of composite support materials A zinc nitrate solution and a 2-methylimidazole solution are prepared respectively, and then the zinc nitrate solution is added to the 2-methylimidazole solution to prepare a carrier powder, and after surface alkalization modification, the carrier powder is added to a mixed solution prepared by disodium hydrogen phosphate, calcium chloride, Tris-HCl buffer and deionized water, and heated to react to obtain a composite carrier powder; S2: Loaded with organic selenium-rich amino acids The organic selenium-rich amino acid is fully dissolved in deionized water at a solid-liquid ratio of 1g: (20-30) mL, and then the composite carrier material is added at a solid-liquid ratio of 1g: (35-45) mL, and ultrasonic loading is performed for 1-2 hours, and then centrifugation, washing and drying are performed to obtain amino acid-loaded powder; S3: Preparation of magnetic composite fillers Illite powder is suspended in deionized water, and then ferric chloride and ferrous chloride are added, and after ultrasonic treatment, potassium hydroxide and urea are added to react to obtain a magnetic composite filler; S4: Preparation of magnetic gel-coated powder The magnetic composite filler is uniformly dispersed in deionized water, and then mixed with chitosan, carboxymethyl cellulose and sodium hyaluronate to prepare chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution respectively, and then the three are mixed and added with the amino acid powder and epichlorohydrin to react to prepare a composite gel, which is freeze-dried and ground to obtain a magnetic gel-coated powder; S5: Formulating organic herbicides The food-grade detergent is mixed with sunflower oil to prepare an emulsifier, and benzoic acid and seaweed essence are dissolved in water to prepare a mixed solution. The silicone oil, the emulsifier and the mixed solution are then mixed and then mixed with the magnetic gel-coated powder to obtain an organic herbicide.

2. The preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium according to claim 1, characterized in that: S1 specifically includes the following steps: S1.1: Add zinc nitrate hexahydrate and 2-methylimidazole into deionized water at a solid-liquid ratio of 1 g: (20-30) mL, stir to dissolve, and ultrasonicate for 5-10 min to obtain zinc nitrate solution and 2-methylimidazole solution; S1.2: Stirring the 2-methylimidazole solution at a rate of 400-500 r / min, then adding an equal volume of the zinc nitrate solution while stirring, continuing stirring for 4-5 hours, standing and aging for 2-3 hours, centrifuging, washing, drying and grinding to obtain a carrier powder; S1.3: Add the above carrier powder to 3 mol / L sodium hydroxide solution at a solid-liquid ratio of 1 g: (10-12) mL, heat and stir at 50-60 ° C for 1.5-2.5 h to perform surface alkalization modification, then filter, wash to neutrality and dry to obtain alkali-modified carrier powder; S1.4: Dissolve disodium hydrogen phosphate in deionized water at a solid-liquid ratio of 1 g: (35-45) mL, then add calcium chloride, stir thoroughly to dissolve, add Tris-HCl buffer to adjust the pH to 7-8, and obtain a mixed solution, wherein the mass ratio of calcium chloride to disodium hydrogen phosphate is (1.8-2.2): 1; S1.5: Add the above-mentioned alkali-modified carrier powder to the above-mentioned mixed solution at a solid-liquid ratio of 1g: (8-10)mL, stir and disperse thoroughly, and then transfer to a hydrothermal reactor, heat and react at 100-120℃ for 4-5h, cool naturally to room temperature, filter, wash and dry to obtain a composite carrier material.

3. The preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium according to claim 2, characterized in that: S3 specifically includes the following steps: S3.1: Add illite powder to deionized water at a solid-liquid ratio of 1 g: (80-90) mL, and ultrasonicate for 1-2 h to obtain an illite suspension; S3.2: Add ferric chloride and ferrous chloride to the above illite suspension in a mass ratio of (1.4-1.6):1, stir and mix evenly, and then ultrasonically treat for 1-2 hours, then add potassium hydroxide and urea in a mass ratio of (1.3-1.5):1, stir and react for 10-12 hours under a nitrogen atmosphere, and obtain a magnetic composite filler after filtering, freeze drying and grinding.

4. The preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium according to claim 3, characterized in that: S4 specifically includes the following steps: S4.1: Disperse the magnetic composite filler prepared in step S3.2 uniformly in deionized water at a solid-liquid ratio of 1 g: (70-80) mL to obtain a magnetic composite filler suspension; S4.2: chitosan, carboxymethyl cellulose and sodium hyaluronate are added to the magnetic composite filler suspension at a solid-liquid ratio of 1 g: (40-50) mL, respectively, and after uniform dispersion, a chitosan mixed solution, a carboxymethyl cellulose mixed solution and a sodium hyaluronate mixed solution are obtained; S4.3: Mix equal masses of the chitosan mixed solution, carboxymethyl cellulose mixed solution and sodium hyaluronate mixed solution, and then add the amino acid powder prepared in step S2 at a solid-liquid ratio of 1 g: (150-160) mL, ultrasonically treat for 20-30 min, add epichlorohydrin, stir to react for 2-3 h, and then stand for 1-2 h to obtain a composite gel, wherein the mass ratio of epichlorohydrin to chitosan is 1: (30-40); S4.4: Place the above composite gel in a freeze dryer for freeze drying, and grind to obtain magnetic gel-coated powder.

5. The preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium according to claim 4, characterized in that: S5 specifically includes the following steps: S5.1: Add food-grade detergent to sunflower oil in a volume ratio of 1:(2.8-3.2), stir and mix thoroughly to obtain an emulsifier; S5.2: Add benzoic acid and seaweed extract into water at a solid-liquid ratio of 1 g: (0.1-0.3) g: (9-11) mL, stir thoroughly to dissolve, and obtain a mixed solution; S5.3: Stir and mix the silicone oil, the emulsifier and the mixed solution in a volume ratio of 1: (3.8-4): (4-4.2) to obtain an organic herbicide. Then add the magnetic gel-coated powder obtained in step S4.4, and continue stirring and mixing to obtain the organic herbicide.

6. The preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium according to claim 3, characterized in that: The solid-liquid ratio of the total mass of ferric chloride and ferrous chloride to the illite suspension is 1 g: (18-20) mL, and the mass ratio of potassium hydroxide to ferric chloride is 1: (12-13).

7. The preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium according to claim 5, characterized in that: The solid-liquid ratio of the magnetic gel-coated powder to the mixed solution is 1 g: (200-220) mL.

8. An organic herbicide for paddy fields capable of enriching rice with selenium, characterized in that: The invention is prepared by the preparation process of an organic herbicide for paddy fields capable of enriching rice with selenium as described in any one of claims 1 to 7.

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