Soil conditioner for degrading fertilizer and pesticide residues in soil and preparation method of soil conditioner

Abstract

The invention relates to the technical field of agriculture, in particular to a soil conditioner for degrading soil fertilizer and pesticide residues and a preparation method thereof, and aims to solve the problems that although an existing soil conditioner can reduce the fertilizer and pesticide residues to a certain extent, secondary pollution is often caused, the cost is high, and the effect of degrading the soil fertilizer and pesticide residues is limited. According to the soil conditioner, humic acid, plant ash, corn straw, kieselguhr, polyglutamic acid and potassium fulvic acid are reasonably compounded, the physical and chemical properties of soil can be improved, the fertility of the soil can be improved, and after the complex microbial inoculants, the loaded pore-increasing charcoal and the coated sodium persulfate are added into the soil conditioner, under the synergistic effect of the three, the soil conditioner can improve the soil fertility. The efficient and long-acting degradation of fertilizer and pesticide residues in the soil is realized, the soil quality, the soil structure and the fertility can be improved, the healthy growth of crops can be promoted, the yield and the quality of the crops can be improved, the sustainable development of agriculture is guaranteed, and finally the comprehensive improvement of the soil is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of agriculture, and particularly relates to a soil conditioner for degrading fertilizer and pesticide residues in soil and a preparation method thereof. Background Art

[0002] With the development of modern agriculture, the extensive use of chemical fertilizers and pesticides not only increases the yield of crops, but also causes the residues and accumulation of these chemical fertilizers and pesticides in the soil, thereby affecting the soil microbial flora and reducing the soil fertility. This not only affects the growth quality of crops, but also may pose a threat to human health through the food chain. Therefore, it is particularly important to develop a soil conditioner that can degrade fertilizer and pesticide residues in soil.

[0003] At present, although the existing soil conditioners on the market can reduce fertilizer and pesticide residues to a certain extent, they are often accompanied by secondary pollution and high costs, and the effect of degrading fertilizer and pesticide residues in soil is limited.

[0004] Therefore, it is of great significance to develop a soil conditioner for degrading fertilizer and pesticide residues in soil and a preparation method thereof. Summary of the Invention

[0005] In order to overcome the above technical problems, the purpose of the present invention is to provide a soil conditioner for degrading fertilizer and pesticide residues in soil and a preparation method thereof, which solves the problems that the existing soil conditioners can reduce fertilizer and pesticide residues to a certain extent, but are often accompanied by secondary pollution, high costs, and limited effect on degrading fertilizer and pesticide residues in soil.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A soil conditioner for degrading fertilizer and pesticide residues in soil, comprising the following components in parts by weight:

[0008] 20 - 26 parts of humic acid, 18 - 22 parts of plant ash, 25 - 31 parts of corn straw, 5 - 9 parts of diatomite, 3 - 6 parts of compound microbial agent, 2 - 10 parts of loaded porous biochar, 1.2 - 2.8 parts of coated sodium persulfate, 1 - 3 parts of polyglutamic acid, and 1 - 3 parts of potassium humate;

[0009] Among them, the loaded porous biochar is prepared by the following steps:

[0010] Step s1: Add bagasse and deionized water into a three-necked flask equipped with a stirrer and a thermometer. Under the conditions of a temperature of 25 - 30°C and an ultrasonic frequency of 30 - 40 kHz, ultrasonically disperse for 20 - 30 min. Then, under the conditions of a temperature of 25 - 30°C and a stirring rate of 200 - 300 r / min, stir and react for 10 - 15 min. After that, raise the temperature to 95 - 100°C and continue to stir and react for 2 - 3 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate with distilled water 2 - 3 times, and then place it in a vacuum drying oven and dry it at a temperature of 60 - 65°C for 3 - 5 h to obtain pretreated bagasse;

[0011] Step s2: Place the pretreated bagasse in a tubular furnace, introduce nitrogen for protection, heat it to 850 - 900°C at a heating rate of 5 - 7°C / min, then keep it at a constant temperature for pyrolysis for 2 - 3 h, then cool it with the furnace, and then crush it and pass it through a 50 - 100 mesh sieve to obtain bagasse biochar;

[0012] Step s3: Add bagasse biochar, potassium hydroxide, and deionized water into a three-necked flask equipped with a stirrer and a thermometer. Under the conditions of a temperature of 25 - 30°C and a stirring rate of 200 - 300 r / min, stir and react for 20 - 30 min. Then, raise the temperature to 80 - 85°C and continue to stir and react for 8 - 10 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate with distilled water 2 - 3 times, and then place it in a vacuum drying oven and dry it at a temperature of 60 - 65°C for 3 - 5 h. Then place it in a tubular furnace, introduce nitrogen for protection, heat it to 650 - 750°C at a heating rate of 5 - 7°C / min, then keep it at a constant temperature for pyrolysis for 2 - 3 h, then cool it with the furnace, then pour it into a hydrochloric acid solution, and then under the conditions of a temperature of 60 - 65°C and a stirring rate of 200 - 300 r / min, stir and react for 4 - 5 h. Then centrifuge, wash the precipitate with distilled water 2 - 3 times, and then place it in a vacuum drying oven and dry it at a temperature of 60 - 65°C for 3 - 5 h to obtain pore-enlarged biochar; After the bagasse biochar is activated by potassium hydroxide, its surface roughness can be increased, and a large number of microporous structures are generated. Then, an acid solution is used to dissolve impurities to further increase the number of micropores and the surface area;

[0013] Step s4: Add ammonium molybdate tetrahydrate, thiourea, and deionized water into a flask, and ultrasonically disperse them for 20 - 30 min under the conditions of a temperature of 25 - 30 °C and an ultrasonic frequency of 30 - 40 kHz. Then add the pore-expanded biochar and continue to ultrasonically disperse for 30 - 50 min. After that, transfer it to a reaction kettle and carry out a hydrothermal reaction at a temperature of 180 - 185 °C and a stirring rate of 200 - 300 r / min for 20 - 30 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge it. Wash the precipitate with distilled water and absolute ethanol 2 - 3 times successively, and then place it in a vacuum drying oven and dry it at a temperature of 80 - 85 °C for 10 - 12 h to obtain the pore-expanded biochar-supported material. A large amount of molybdenum disulfide can be loaded on the surface and internal micropores of the pore-expanded biochar by the hydrothermal reaction of ammonium molybdate tetrahydrate and thiourea.

[0014] As a further scheme of the present invention: The dosage ratio of the bagasse and deionized water in step s1 is 10 g: 80 - 100 mL.

[0015] As a further scheme of the present invention: The dosage ratio of the bagasse biochar, potassium hydroxide, deionized water, and hydrochloric acid solution in step s3 is 5 g: 4 - 10 g: 100 - 120 mL: 40 - 50 mL.

[0016] As a further scheme of the present invention: The mass fraction of the hydrochloric acid solution in step s3 is 5 - 10%.

[0017] As a further scheme of the present invention: The dosage ratio of the ammonium molybdate tetrahydrate, thiourea, deionized water, and pore-expanded biochar in step s4 is 30 - 35 mmol: 10 mmol: 80 - 100 mL: 5 g.

[0018] As a further scheme of the present invention: The coated sodium persulfate is prepared by the following steps:

[0019] Add paraffin into a three-necked flask equipped with a stirrer and a thermometer, and stir and react for 20 - 30 min under the conditions of a temperature of 55 - 60 °C and a stirring rate of 200 - 300 r / min. Then add the sodium persulfate sieved through a 100 - 150 mesh sieve and continue to stir and react for 40 - 50 min. After the reaction is completed, drop the reaction product into ice water while it is hot, and then carry out vacuum filtration. Crush the filter cake through a sieve with a pore size of 1 - 2 mm to obtain the coated sodium persulfate.

[0020] As a further scheme of the present invention: The dosage ratio of the paraffin and sodium persulfate is 10 g: 7 - 9 g.

[0021] As a further scheme of the present invention: The melting point of the paraffin is 52 - 54 °C.

[0022] As a further solution of the present invention: A preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, comprising the following steps:

[0023] Step 1: Weigh 20-26 parts of humic acid, 18-22 parts of plant ash, 25-31 parts of corn straw, 5-9 parts of diatomite, 3-6 parts of compound bacterial agent, 2-10 parts of loaded porous biochar, 1.2-2.8 parts of coated sodium persulfate, 1-3 parts of polyglutamic acid and 1-3 parts of potassium humate by weight, and set aside;

[0024] Step 2: Add humic acid, plant ash, corn straw, diatomite, compound bacterial agent, loaded porous biochar, coated sodium persulfate, polyglutamic acid and potassium humate into a mixer, and stir and mix at a temperature of 20-25 °C and a stirring rate of 500-600 r / min for 20-30 min. Then add clear water to adjust the water content to 30-35%, and then granulate through an extrusion granulator. Then dry at a temperature of 35-40 °C until the water content is 5-7% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0025] As a further solution of the present invention: The compound bacterial agent is a mixture of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobactrum intermedium, Arthrobacter and Candida albicans with a viable count of ≥5×10 9 CFU / g in equal mass.

[0026] Advantages of the present invention:

[0027] A soil conditioner for degrading soil fertilizer and pesticide residues and its preparation method of the present invention mix humic acid, plant ash, corn straw, diatomite, compound bacterial agent, loaded porous biochar, coated sodium persulfate, polyglutamic acid and potassium humate by stirring, then add clear water and granulate through an extrusion granulator, and then dry to obtain a soil conditioner for degrading soil fertilizer and pesticide residues; the soil conditioner rationally combines humic acid, plant ash, corn straw, diatomite, polyglutamic acid and potassium humate, can improve the physical and chemical properties of the soil, can improve the soil fertility, provide sufficient nutrients for crop growth, increase the air permeability and water retention of the soil, promote the growth of crop roots, and after adding the compound bacterial agent, loaded porous biochar and coated sodium persulfate, under the synergistic effect of the three, the efficient and long-term degradation of fertilizer and pesticide residues in the soil is realized, which can not only improve the soil quality, improve the soil structure and fertility, but also promote the healthy growth of crops, improve the yield and quality of agricultural products, ensure the sustainable development of agriculture, and finally realize the comprehensive improvement of the soil.

[0028] The composite microbial agent contains a large number of different types of microorganisms. Under the synergistic action of various microorganisms, it enhances the decomposition ability of organic matter in the soil, improves the soil fertility, and at the same time promotes the biodegradation of pesticide residues by microorganisms; the pore-expanded biochar loaded with pore-expanded biochar serves as a carrier, which can not only provide an excellent growth environment for microorganisms, but also fully absorb fertilizers and pesticides, improving the effect of microorganisms in decomposing fertilizers and pesticides. The molybdenum disulfide loaded on it has a narrow band gap and has light absorption properties under ultraviolet and visible light, making it have high photocatalytic activity and can accelerate the photocatalytic decomposition of pesticide residues under light conditions. And molybdenum disulfide can provide molybdenum ions, which have strong activation activity and affinity for persulfate, can activate persulfate and generate a large amount of sulfate radicals. Sulfate radicals are radicals with a high redox potential, thus degrading pesticide residues that are difficult to biodegrade. And the coated sodium persulfate can make sodium persulfate release slowly, and then can achieve long-term degradation of pesticide residues; the whole modifier forms a complete improvement system through the synergistic action of multiple mechanisms, realizes the efficient and long-term degradation of fertilizer and pesticide residues in the soil, is environmentally friendly and harmless, and finally realizes the effective degradation of fertilizer and pesticide residues in the soil and the improvement of soil quality. Detailed implementation manners

[0029] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0030] Example 1:

[0031] This example is a preparation method of a soil modifier for degrading fertilizer and pesticide residues in soil, including the following steps:

[0032] Step S1: Add 10 g of bagasse and 80 mL of deionized water to a three-necked flask equipped with a stirrer and a thermometer, ultrasonically disperse for 20 min under the conditions of a temperature of 25 °C and an ultrasonic frequency of 30 kHz, then stir and react for 10 min under the conditions of a temperature of 25 °C and a stirring rate of 200 r / min, and then continue to stir and react for 2 h under the condition of heating to 95 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate twice with distilled water, and then place it in a vacuum drying oven and dry for 3 h under the condition of a temperature of 60 °C to obtain pretreated bagasse;

[0033] Step S2: Place the pretreated bagasse in a tubular furnace, introduce nitrogen for protection, heat it to 850 °C at a heating rate of 5 °C / min, then keep it pyrolyzed at a constant temperature for 2 h, then cool it with the furnace, then crush it and sieve it through a 50-mesh sieve to obtain bagasse biochar;

[0034] Step S3: Add 5 g of bagasse biochar, 4 g of potassium hydroxide, and 100 mL of deionized water into a three-necked flask equipped with a stirrer and a thermometer, stir and react at a temperature of 25 °C and a stirring rate of 200 r / min for 20 min, then continue to stir and react at a temperature of 80 °C for 8 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge it, wash the precipitate with distilled water twice, then place it in a vacuum drying oven, dry it at a temperature of 60 °C for 3 h, then place it in a tubular furnace, introduce nitrogen for protection, heat it to 650 °C at a heating rate of 5 °C / min, then keep it pyrolyzed at a constant temperature for 2 h, then cool it with the furnace, then pour it into 40 mL of a hydrochloric acid solution with a mass fraction of 5%, then stir and react at a temperature of 60 °C and a stirring rate of 200 r / min for 4 h, then centrifuge it, wash the precipitate with distilled water twice, then place it in a vacuum drying oven, dry it at a temperature of 60 °C for 3 h to obtain pore-expanded biochar;

[0035] Step S4: Add 30 mmol of ammonium molybdate tetrahydrate, 10 mmol of thiourea, and 80 mL of deionized water into a flask, ultrasonically disperse it at a temperature of 25 °C and an ultrasonic frequency of 30 kHz for 20 min, then add 5 g of pore-expanded biochar and continue to ultrasonically disperse it for 30 min, then add it into a reaction kettle, and carry out hydrothermal reaction at a temperature of 180 °C and a stirring rate of 200 r / min for 20 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge it, wash the precipitate with distilled water and absolute ethanol twice respectively, then place it in a vacuum drying oven, dry it at a temperature of 80 °C for 10 h to obtain supported pore-expanded biochar;

[0036] Step S5: Add 10 g of paraffin with a melting point of 52 °C into a three-necked flask equipped with a stirrer and a thermometer, stir and react at a temperature of 55 °C and a stirring rate of 200 r / min for 20 min, then add 7 g of sodium persulfate sieved through a 100-mesh sieve and continue to stir and react for 40 min. After the reaction is completed, quickly drop the reaction product into ice water while it is hot, then carry out vacuum filtration, crush the filter cake and sieve it through a sieve with a pore diameter of 1 mm to obtain sodium persulfate-coated product;

[0037] Step S6: Weigh 20 parts of humic acid, 18 parts of plant ash, 25 parts of corn straw, 5 parts of diatomite, and viable bacteria count ≥ 5×10 93 parts of a composite bacterial agent composed of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobactrum intermedium, Arthrobacter, and Candida albicans mixed in equal mass, 2 parts of pore-increasing biochar support, 1.2 parts of coated sodium persulfate, 1 part of polyglutamic acid, and 1 part of potassium humate are prepared for later use;

[0038] Step S7: Add humic acid, plant ash, corn straw, diatomite, the composite bacterial agent, pore-increasing biochar support, coated sodium persulfate, polyglutamic acid, and potassium humate to a mixer, and stir and mix for 20 min under the conditions of a temperature of 20°C and a stirring rate of 500 r / min. Then add clear water to adjust the water content to 30%, and then granulate through an extrusion granulator. After that, dry at a temperature of 35°C until the water content is 5% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0039] Example 2:

[0040] This example is a preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, including the following steps:

[0041] Step S1: Add 10 g of bagasse and 90 mL of deionized water to a three-necked flask equipped with a stirrer and a thermometer, ultrasonically disperse for 25 min under the conditions of a temperature of 28°C and an ultrasonic frequency of 35 kHz, then stir and react for 12 min under the conditions of a temperature of 28°C and a stirring rate of 250 r / min, and then continue to stir and react for 2.5 h under the condition of heating to 98°C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate twice with distilled water, and then place it in a vacuum drying oven and dry at a temperature of 62°C for 4 h to obtain pretreated bagasse;

[0042] Step S2: Place the pretreated bagasse in a tubular furnace, introduce nitrogen for protection, heat it to 875°C at a heating rate of 6°C / min, then keep it at a constant temperature and pyrolyze for 2.5 h, then cool it with the furnace, and then crush and pass through a 75-mesh sieve to obtain bagasse biochar;

[0043] Step S3: Add 5 g of bagasse biochar, 7 g of potassium hydroxide, and 110 mL of deionized water into a three-necked flask equipped with a stirrer and a thermometer. Stir and react for 25 min at a temperature of 28 °C and a stirring rate of 250 r / min. Then, continue to stir and react for 9 h under the condition of raising the temperature to 82 °C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate twice with distilled water, then place it in a vacuum drying oven and dry it for 4 h at a temperature of 62 °C. Then, place it in a tube furnace, introduce nitrogen for protection, heat it up to 700 °C at a heating rate of 6 °C / min, then keep it at a constant temperature for pyrolysis for 2.5 h, then cool it with the furnace. Then, pour it into 45 mL of hydrochloric acid solution with a mass fraction of 7%. Then, stir and react for 4.5 h at a temperature of 62 °C and a stirring rate of 250 r / min. Then, centrifuge. Wash the precipitate twice with distilled water, then place it in a vacuum drying oven and dry it for 4 h at a temperature of 62 °C to obtain the pore-enlarged biochar;

[0044] Step S4: Add 32 mmol of ammonium molybdate tetrahydrate, 10 mmol of thiourea, and 90 mL of deionized water into a flask. Ultrasonically disperse for 25 min at a temperature of 28 °C and an ultrasonic frequency of 35 kHz. Then, add 5 g of pore-enlarged biochar and continue to ultrasonically disperse for 40 min. Then, add it into a reaction kettle and hydrothermally react for 25 h at a temperature of 182 °C and a stirring rate of 250 r / min. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate twice with distilled water and twice with absolute ethanol in sequence. Then, place it in a vacuum drying oven and dry it for 11 h at a temperature of 82 °C to obtain the supported pore-enlarged biochar;

[0045] Step S6: Weigh 23 parts of humic acid, 20 parts of plant ash, 28 parts of corn straw, 7 parts of diatomite, 4.5 parts of a composite bactericide composed of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobactrum intermedium, Arthrobacter, and Candida albicans with a viable bacteria count ≥ 5×10

[0046] CFU / g by mixing them in equal mass, 6 parts of supported pore-enlarged biochar, 2 parts of coated sodium persulfate, 2 parts of polyglutamic acid, and 2 parts of potassium humate, and set aside; 9 CFU / g of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobactrum intermedium, Arthrobacter, and Candida albicans mixed in equal mass, 4.5 parts of the composite bactericide, 6 parts of the supported pore-enlarged biochar, 2 parts of the coated sodium persulfate, 2 parts of polyglutamic acid, and 2 parts of potassium humate, and set aside;

[0047] Step S7: Add humic acid, plant ash, corn straw, diatomite, compound microbial agent, pore-increasing biochar support, coated sodium persulfate, polyglutamic acid, and potassium humate into a mixer, stir and mix for 25 min under the conditions of a temperature of 22°C and a stirring rate of 550 r / min, then add clear water to adjust the water content to 32%, then granulate by an extrusion granulator, and then dry at a temperature of 38°C until the water content is 6% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0048] Example 3:

[0049] This example is a preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, including the following steps:

[0050] Step S1: Add 10 g of bagasse and 100 mL of deionized water into a three-necked flask equipped with a stirrer and a thermometer, ultrasonically disperse for 30 min under the conditions of a temperature of 30°C and an ultrasonic frequency of 40 kHz, then stir and react for 15 min under the conditions of a temperature of 30°C and a stirring rate of 300 r / min, then continue to stir and react for 3 h under the condition of raising the temperature to 100°C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water 3 times, and then place it in a vacuum drying oven and dry at a temperature of 65°C for 5 h to obtain pretreated bagasse;

[0051] Step S2: Place the pretreated bagasse in a tubular furnace, introduce nitrogen for protection, raise the temperature to 900°C at a heating rate of 7°C / min, then keep the temperature constant and pyrolyze for 3 h, then cool with the furnace, and then crush and pass through a 100-mesh sieve to obtain bagasse biochar;

[0052] Step S3: Add 5 g of bagasse biochar, 10 g of potassium hydroxide, and 120 mL of deionized water into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 30 min under the conditions of a temperature of 30°C and a stirring rate of 300 r / min, then continue to stir and react for 10 h under the condition of raising the temperature to 85°C. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water 3 times, and then place it in a vacuum drying oven and dry at a temperature of 65°C for 5 h. Then place it in a tubular furnace, introduce nitrogen for protection, raise the temperature to 750°C at a heating rate of 7°C / min, then keep the temperature constant and pyrolyze for 3 h, then cool with the furnace, then pour it into 50 mL of a hydrochloric acid solution with a mass fraction of 10%, and then stir and react for 5 h under the conditions of a temperature of 65°C and a stirring rate of 300 r / min, then centrifuge, wash the precipitate with distilled water 3 times, and then place it in a vacuum drying oven and dry at a temperature of 65°C for 5 h to obtain pore-increasing biochar;

[0053] Step S4: Add 35 mmol ammonium molybdate tetrahydrate, 10 mmol thiourea, and 100 mL deionized water into a flask. Under the conditions of a temperature of 30 °C and an ultrasonic frequency of 40 kHz, ultrasonically disperse for 30 min. Then add 5 g of pore-expanded biochar and continue ultrasonically dispersing for 50 min. After that, transfer it to a reaction kettle and carry out hydrothermal reaction at a temperature of 185 °C and a stirring rate of 300 r / min for 30 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge. Wash the precipitate with distilled water and absolute ethanol three times in sequence. Then place it in a vacuum drying oven and dry at a temperature of 85 °C for 12 h to obtain the pore-expanded biochar-supported product;

[0054] Step S5: Add 10 g of paraffin with a melting point of 54 °C into a three-necked flask equipped with a stirrer and a thermometer. Under the conditions of a temperature of 60 °C and a stirring rate of 300 r / min, stir and react for 30 min. Then add 9 g of sodium persulfate that has been pulverized and passed through a 150-mesh sieve and continue stirring and reacting for 50 min. After the reaction is completed, quickly drop the reaction product into ice water, then carry out vacuum filtration. Pulverize the filter cake and pass it through a sieve with a pore size of 2 mm to obtain the sodium persulfate-coated product;

[0055] Step S6: Weigh 26 parts of humic acid, 22 parts of plant ash, 31 parts of corn straw, 9 parts of diatomite, and a composite bactericide composed of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobactrum intermedium, Arthrobacter, and Candida albicans with a viable bacteria count ≥ 5×10 9 CFU / g, mixed in equal mass, 6 parts, 10 parts of the pore-expanded biochar-supported product, 2.8 parts of the sodium persulfate-coated product, 3 parts of polyglutamic acid, and 3 parts of potassium fulvate, and set aside;

[0056] Step S7: Add humic acid, plant ash, corn straw, diatomite, the composite bactericide, the pore-expanded biochar-supported product, the sodium persulfate-coated product, polyglutamic acid, and potassium fulvate into a mixer. Under the conditions of a temperature of 25 °C and a stirring rate of 600 r / min, stir and mix for 30 min. Then add clear water to adjust the water content to 35%. Then granulate through an extrusion granulator, and then dry at a temperature of 40 °C until the water content is 7% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0057] Comparative Example 1:

[0058] This comparative example is a preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, including the following steps:

[0059] Step S1: Weigh 26 parts of humic acid, 22 parts of plant ash, 31 parts of corn straw, 9 parts of diatomite, 3 parts of polyglutamic acid, and 3 parts of potassium fulvate, and set aside;

[0060] Step S2: Add humic acid, plant ash, corn straw, diatomite, polyglutamic acid, and potassium humate into a mixer, stir and mix for 30 min at a temperature of 25°C and a stirring rate of 600 r / min. Then add clear water to adjust the water content to 35%, and then granulate through an extrusion granulator. After that, dry at a temperature of 40°C until the water content is 7% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0061] Comparative Example 2:

[0062] This comparative example is a preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, including the following steps:

[0063] Step S1: Weigh 26 parts of humic acid, 22 parts of plant ash, 31 parts of corn straw, 9 parts of diatomite, a composite bacterial agent composed of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobactrum intermedium, Arthrobacter, and Candida albicans with a viable count ≥ 5×10 9 CFU / g by equal mass, 3 parts of polyglutamic acid, and 3 parts of potassium humate, and set aside;

[0064] Step S2: Add humic acid, plant ash, corn straw, diatomite, the composite bacterial agent, polyglutamic acid, and potassium humate into a mixer, stir and mix for 30 min at a temperature of 25°C and a stirring rate of 600 r / min. Then add clear water to adjust the water content to 35%, and then granulate through an extrusion granulator. After that, dry at a temperature of 40°C until the water content is 7% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0065] Comparative Example 3:

[0066] This comparative example is a preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, including the following steps:

[0067] Step S1: Add 10 g of bagasse and 100 mL of deionized water into a three-necked flask equipped with a stirrer and a thermometer, ultrasonically disperse for 30 min at a temperature of 30°C and an ultrasonic frequency of 40 kHz. Then stir and react for 15 min at a temperature of 30°C and a stirring rate of 300 r / min. Then raise the temperature to 100°C and continue to stir and react for 3 h. After the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water 3 times, and then place it in a vacuum drying oven and dry at a temperature of 65°C for 5 h to obtain pretreated bagasse;

[0068] Step S2: Place the pretreated bagasse in a tube furnace, introduce nitrogen for protection, heat it to 900 °C at a heating rate of 7 °C / min, then keep it pyrolyzed at a constant temperature for 3 h, then cool it with the furnace, then crush it and sieve it through a 100-mesh sieve to obtain bagasse biochar;

[0069] Step S3: Add 5 g of bagasse biochar, 10 g of potassium hydroxide, and 120 mL of deionized water into a three-necked flask equipped with a stirrer and a thermometer, stir and react at a temperature of 30 °C and a stirring rate of 300 r / min for 30 min, then continue to stir and react at a temperature of 85 °C for 10 h. After the reaction, cool the reaction product to room temperature, then centrifuge it, wash the precipitate with distilled water 3 times, then place it in a vacuum drying oven and dry it at a temperature of 65 °C for 5 h. Then place it in a tube furnace, introduce nitrogen for protection, heat it to 750 °C at a heating rate of 7 °C / min, then keep it pyrolyzed at a constant temperature for 3 h, then cool it with the furnace, then pour it into 50 mL of a hydrochloric acid solution with a mass fraction of 10%, then stir and react at a temperature of 65 °C and a stirring rate of 300 r / min for 5 h, then centrifuge it, wash the precipitate with distilled water 3 times, then place it in a vacuum drying oven and dry it at a temperature of 65 °C for 5 h to obtain pore-expanded biochar;

[0070] Step S4: Add 35 mmol of ammonium molybdate tetrahydrate, 10 mmol of thiourea, and 100 mL of deionized water into a flask, ultrasonically disperse it at a temperature of 30 °C and an ultrasonic frequency of 40 kHz for 30 min, then add 5 g of pore-expanded biochar and continue to ultrasonically disperse it for 50 min, then add it into a reaction kettle and hydrothermally react at a temperature of 185 °C and a stirring rate of 300 r / min for 30 h. After the reaction, cool the reaction product to room temperature, then centrifuge it, wash the precipitate with distilled water and absolute ethanol 3 times each, then place it in a vacuum drying oven and dry it at a temperature of 85 °C for 12 h to obtain supported pore-expanded biochar;

[0071] Step S5: Weigh 26 parts of humic acid, 22 parts of plant ash, 31 parts of corn straw, 9 parts of diatomite, 10 parts of supported pore-expanded biochar, 3 parts of polyglutamic acid, and 3 parts of potassium humate by weight, and set aside;

[0072] Step S6: Add humic acid, plant ash, corn straw, diatomite, supported pore-expanded biochar, polyglutamic acid, and potassium humate into a mixer, stir and mix at a temperature of 25 °C and a stirring rate of 600 r / min for 30 min, then add clear water to adjust the water content to 35%, then granulate it through an extrusion granulator, and then dry it at a temperature of 40 °C until the water content is 7% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0073] Comparative Example 4:

[0074] This comparative example is a preparation method of a soil conditioner for degrading soil fertilizer and pesticide residues, including the following steps:

[0075] Step S1: Add 10 g of paraffin with a melting point of 54 °C into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 30 min at a temperature of 60 °C and a stirring rate of 300 r / min. Then add 9 g of sodium persulfate that has been pulverized and passed through a 150-mesh sieve, and continue to stir and react for 50 min. After the reaction ends, drop the reaction product into ice water while it is hot, and then perform vacuum filtration. Pulverize the filter cake and pass it through a sieve with a pore size of 2 mm to obtain sodium persulfate coated.

[0076] Step S2: Weigh 26 parts of humic acid, 22 parts of plant ash, 31 parts of corn straw, 9 parts of diatomite, 2.8 parts of sodium persulfate coated, 3 parts of polyglutamic acid, and 3 parts of potassium humate by weight, and set aside.

[0077] Step S3: Add humic acid, plant ash, corn straw, diatomite, sodium persulfate coated, polyglutamic acid, and potassium humate into a mixer, stir and mix for 30 min at a temperature of 25 °C and a stirring rate of 600 r / min. Then add clear water to adjust the water content to 35%, and then granulate through an extrusion granulator. Then dry at a temperature of 40 °C until the water content is 7% to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

[0078] Blank control example:

[0079] Dissolve the pesticide sample in 100 mL of acetone to prepare a pesticide sample solution with a concentration of 250 mg / L. Then slowly pour the pesticide sample solution into 500 g of soil multiple times and mix well. Then place the soil containing the pesticide sample in a fume hood for 7 d to allow the acetone in the soil to volatilize. After the acetone has volatilized, put the soil into a brown glass bottle, seal it, and test its pesticide sample content.

[0080] Detection example:

[0081] Dissolve the pesticide sample in 100 mL of acetone to prepare a pesticide sample solution with a concentration of 250 mg / L. Then slowly pour the pesticide sample solution into 500 g of soil multiple times and mix well. Then add 5 g of the soil conditioner for degrading soil fertilizer and pesticide residues from Examples 1-3 and Comparative Examples 1-4, and continue to mix well. Then place the soil containing the pesticide sample in a fume hood for 7 d to allow the acetone in the soil to volatilize. After the acetone has volatilized, put the soil into a brown glass bottle, seal it, and test its pesticide sample content;

[0082] Among them, the pesticide samples are atrazine, acetochlor, and butachlor, and the test results are shown in the following table:

[0083] Test sample Atrazine content, mg / kg Acetochlor content, mg / kg Butachlor content, mg / kg Example 1 5.84 5.24 6.11 Example 2 5.40 4.01 5.96 Example 3 4.03 3.13 3.64 Comparative Example 1 36.34 35.23 37.43 Comparative Example 2 24.06 23.00 25.12 Comparative Example 3 18.66 17.61 19.45 Comparative Example 4 18.17 16.15 18.72 Blank control example 49.11 48.93 49.25

[0084] Referring to the data in the above table, it can be known that the soil conditioner for degrading soil fertilizer and pesticide residues in this application has excellent degradation effect on pesticides.

[0085] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0086] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the invention or exceed the scope defined by this application, they should all belong to the protection scope of the present invention.

Claims

1. A soil conditioner for degrading soil fertilizer and pesticide residues, characterized in that: It comprises the following components in parts by weight: 20-26 parts of humic acid, 18-22 parts of plant ash, 25-31 parts of corn stalks, 5-9 parts of diatomaceous earth, 3-6 parts of composite bacterial agent, 2-10 parts of loaded pore-enhancing biochar, 1.2-2.8 parts of coated sodium persulfate, 1-3 parts of polyglutamic acid and 1-3 parts of potassium humate; Wherein, the loaded pore-enhanced biochar is prepared by the following steps: Step s1: Add bagasse and deionized water into a three-necked flask equipped with a stirrer and a thermometer, perform ultrasonic dispersion for 20-30 minutes at a temperature of 25-30°C and an ultrasonic frequency of 30-40kHz, then stir and react for 10-15 minutes at a temperature of 25-30°C and a stirring rate of 200-300r / min, then heat to 95-100°C and continue stirring and reacting for 2-3 hours, after the reaction is completed, cool the reaction product to room temperature, then centrifuge, wash the precipitate with distilled water for 2-3 times, then place it in a vacuum drying oven, and dry it at a temperature of 60-65°C for 3-5 hours to obtain pretreated bagasse; Step s2: placing the pretreated bagasse in a tubular furnace, introducing nitrogen protection, heating to 850-900°C at a heating rate of 5-7°C / min, then pyrolyzing at a constant temperature for 2-3h, then cooling with the furnace, and then crushing through a 50-100 mesh sieve to obtain bagasse biochar; Step s3: Add bagasse biochar, potassium hydroxide and deionized water to a three-necked flask equipped with a stirrer and a thermometer, stir and react for 20-30 minutes at a temperature of 25-30°C and a stirring rate of 200-300 r / min, then heat to 80-85°C and continue stirring and reacting for 8-10 hours. After the reaction is completed, cool the reaction product to room temperature, centrifuge it, wash the precipitate with distilled water for 2-3 times, and then place it in a vacuum drying oven and dry it at a temperature of 60-65°C for 3-5 minutes. h, then placed in a tubular furnace, nitrogen protection was introduced, the temperature was raised to 650-750°C at a heating rate of 5-7°C / min, and then pyrolyzed at a constant temperature for 2-3h, then cooled with the furnace, and then poured into a hydrochloric acid solution, and then stirred for 4-5h at a temperature of 60-65°C and a stirring rate of 200-300r / min, and then centrifuged, the precipitate was washed with distilled water 2-3 times, and then placed in a vacuum drying oven, and dried at a temperature of 60-65°C for 3-5h to obtain porous biochar; Step s4: Add ammonium molybdate tetrahydrate, thiourea and deionized water into a flask, and ultrasonically disperse them for 20-30 minutes at a temperature of 25-30°C and an ultrasonic frequency of 30-40kHz. Then add the pore-enhancing biochar and continue ultrasonically dispersing it for 30-50 minutes. Then add it into a reactor and hydrothermally react it for 20-30 hours at a temperature of 180-185°C and a stirring rate of 200-300r / min. After the reaction, cool the reaction product to room temperature and then centrifuge it. Wash the precipitate with distilled water and anhydrous ethanol for 2-3 times in turn, and then place it in a vacuum drying oven and dry it at a temperature of 80-85°C for 10-12 hours to obtain loaded pore-enhancing biochar.

2. A soil conditioner for degrading soil fertilizer and pesticide residues according to claim 1, characterized in that: The usage ratio of the bagasse and deionized water in step s1 is 10g:80-100mL.

3. A soil conditioner for degrading soil fertilizer and pesticide residues according to claim 1, characterized in that: The dosage ratio of the bagasse biochar, potassium hydroxide, deionized water and hydrochloric acid solution in step s3 is 5g:4-10g:100-120mL:40-50mL.

4. A soil conditioner for degrading soil fertilizer and pesticide residues according to claim 1, characterized in that: The mass fraction of the hydrochloric acid solution in step s3 is 5-10%.

5. The soil conditioner for degrading soil fertilizer and pesticide residues according to claim 1, characterized in that: The usage ratio of the ammonium molybdate tetrahydrate, thiourea, deionized water and pore-enhancing biochar in step s4 is 30-35 mmol: 10 mmol: 80-100 mL: 5 g.

6. The soil conditioner for degrading soil fertilizer and pesticide residues according to claim 1, characterized in that: The coated sodium persulfate is prepared by the following steps: Add paraffin wax into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 20-30 minutes at a temperature of 55-60°C and a stirring rate of 200-300 r / min, then add sodium persulfate crushed through a 100-150 mesh sieve and continue stirring and reacting for 40-50 minutes. After the reaction is completed, drop the reaction product into ice water while hot, then vacuum filter, crush the filter cake through a sieve with a pore size of 1-2 mm, and obtain coated sodium persulfate.

7. A soil conditioner for degrading soil fertilizer and pesticide residues according to claim 6, characterized in that: The usage ratio of the paraffin wax and sodium persulfate is 10g:7-9g.

8. The soil conditioner for degrading soil fertilizer and pesticide residues according to claim 6, characterized in that: The melting point of the paraffin wax is 52-54°C.

9. A method for preparing a soil conditioner for degrading soil fertilizer and pesticide residues as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Weigh 20-26 parts of humic acid, 18-22 parts of wood ash, 25-31 parts of corn stalks, 5-9 parts of diatomaceous earth, 3-6 parts of composite bacterial agent, 2-10 parts of loaded pore-increasing biochar, 1.2-2.8 parts of coated sodium persulfate, 1-3 parts of polyglutamic acid and 1-3 parts of potassium humate according to weight, and set aside; Step 2: Add humic acid, wood ash, corn stalks, diatomaceous earth, composite bacterial agent, loaded pore-enhancing biochar, coated sodium persulfate, polyglutamic acid and potassium humate into a mixer, stir and mix for 20-30 minutes at a temperature of 20-25°C and a stirring rate of 500-600r / min, then add clean water to adjust the moisture content to 30-35%, then granulate and form through an extrusion granulator, and then dry to a moisture content of 5-7% at a temperature of 35-40°C to obtain a soil conditioner for degrading soil fertilizer and pesticide residues.

10. The method for preparing a soil conditioner for degrading soil fertilizer and pesticide residues according to claim 9, characterized in that: The number of viable bacteria in the composite bacterial agent is ≥5×10 9 CFU / g of Serratia marcescens, Bacillus cereus, Bacillus licheniformis, Ochrobacter intermedia, Arthrobacter and Candida species were mixed in equal amounts.