Application of iron-containing nanomaterials in reducing fomesafen residues and reduction methods

Abstract

The present invention relates to the technical field of soil remediation, and discloses the application of iron-containing nanomaterials in reducing fomesafen residues, wherein the iron-containing nanomaterials are nano-ferric oxide or nano-iron, and the fomesafen residues are fomesafen residues in soybean field soil. The method for reducing fomesafen residues in soybean field soil specifically comprises the following steps: using the iron-containing nanomaterials to configure an iron-containing nano suspension, the concentration of the iron-containing nano suspension is 5mg / L-10mg / L; planting soybeans in the soil with fomesafen residues, and 40-50 days after soybean planting, watering the soybean roots with the iron-containing nano suspension. The present invention provides the application of iron-containing nanomaterials in reducing fomesafen residues, and the method for reducing fomesafen residues in soybean field soil by iron-containing nanomaterials is rhizosphere in-situ intensive reduction, which quickly reduces the concentration of fomesafen in the soil, avoids competition with indigenous microorganisms, and ensures the repair effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation, and in particular relates to the application of iron-containing nanomaterials in reducing fomesafen residues and a reduction method. Background Art

[0002] Fomesulfuron is a diphenyl ether herbicide widely used in peanut and soybean fields. It has strong selectivity and good weed control effect. Since its introduction into my country, the use of fomesulfuron has continued to rise, and long-term and large-scale application has led to obvious residues in the soil. The residual fomesulfuron is prone to cause phytotoxicity to subsequent sensitive crops, resulting in a decrease in crop yields, which greatly affects the agricultural planting structure and food production. In addition, fomesulfuron that enters the environment will be enriched in organisms and enter the food chain, thereby threatening ecological safety and human health. Therefore, the problem of fomesulfuron residues in farmland soil urgently needs to be paid attention to and taken seriously.

[0003] At present, the reduction technology for fomesafen in soil mainly focuses on microbial degradation technology. Soil microorganisms play an important role in the reduction process of fomesafen. Studies have shown that the degradation rate of fomesafen is reduced by about 200.0% after soil sterilization, and the addition of degrading bacteria can reduce the half-life of fomesafen in soil from 93d to 30d. So far, researchers have isolated and screened 18 fomesafen-degrading bacteria. From the perspective of species distribution, 13 fomesafen-degrading strains are bacteria and the remaining 5 are fungi. For example, Sinorhizobium sp. W16 reported in patent CN110904005 B can stably degrade fomesafen and can be applied to farmland where fomesafen is applied. However, due to the competitive relationship between the microorganisms added by biofortification and the indigenous microorganisms, it is limited by environmental factors and available nutrient supply. In the actual remediation process, it takes several months or even longer. Therefore, it is urgent to develop other substances that can reduce soil remediation time to reduce the residues of fomesafen. Summary of the invention

[0004] The present invention provides an application of iron-containing nanomaterials in reducing fomesafen residues and a reduction method, which solves the problem that the prior art uses microorganisms to degrade fomesafen residues in soil, but the actual restoration time required is as long as several months or even longer.

[0005] The invention discloses an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials are nano-ferroferric oxide or nano-iron, and the fomesafen residues are fomesafen residues in soybean field soil.

[0006] Preferably, the particle size of the nano-ferroferric oxide is 10nm-30nm, and the particle size of the nano-iron is 50nm-80nm.

[0007] A method for reducing fomesafen residues in soybean field soil, specifically comprising the following steps:

[0008] The iron-containing nanomaterial is used to prepare an iron-containing nano suspension, wherein the concentration of the iron-containing nano suspension is 5 mg / L-10 mg / L;

[0009] Soybeans are planted in the soil containing fomesafen residues, and 40-50 days after the soybeans are planted, the iron-containing nanosuspension is irrigated onto the roots of the soybeans.

[0010] 40 to 50 days after soybean planting is the early flowering period of soybeans, which is also an important period for nodule formation. Iron plays an important role in nodule formation. Adding iron nanomaterials during this period may affect nodule formation, thereby regulating the composition and structure of rhizobia and rhizosphere microorganisms, and further affecting the degradation of fomesafen in the soil.

[0011] The iron-containing nanosuspension in the concentration range of 5mg / L-10mg / L has a good promoting effect on soybean growth, especially on root growth. The promotion of root growth or nodules may regulate the changes in the structure or composition of rhizobia or rhizosphere microorganisms, thereby affecting the degradation of fomesafen. Too high a concentration will inhibit soybean growth, and too low a concentration will not produce a promoting effect.

[0012] Preferably, the iron-containing nano suspension is a nano-ferroferric oxide suspension or a nano-iron suspension.

[0013] Preferably, when the iron-containing nano suspension is a nano ferroferric oxide suspension, the particle size of the nano ferroferric oxide is 10nm-30nm, and the purity is 99.9%. If the particle size of the nano ferroferric oxide is too large, it is not easy to disperse, and if the particle size is too small, it is not easy to obtain.

[0014] Preferably, the irrigation amount of the nano-ferroferric oxide suspension is: 50mL-80mL of the nano-ferroferric oxide suspension is irrigated per kg of fomesafen residual soil. If the irrigation amount is too small, the fomesafen concentration in the soil cannot be quickly reduced; if the irrigation amount is too large, it will affect the growth of soybeans.

[0015] Preferably, the nano-ferroferric oxide suspension is watered once a day for 5 to 6 consecutive days.

[0016] Preferably, after continuous irrigation for 5 to 6 days, the concentration of nano-ferroferric oxide in the soybean field soil is 1.25 mg kg -1 ~4.80mg·kg -1 .

[0017] Preferably, the specific method for preparing the nano-ferroferric oxide suspension is: dispersing the nano-ferroferric oxide in water, and obtaining the nano-ferroferric oxide pouring suspension with a concentration of 5 mg / L-10 mg / L after ultrasonic treatment.

[0018] Preferably, the ultrasonic power is 800W-1000W, the temperature is 20°C-25°C, and the ultrasonic time is 1h-4h.

[0019] Preferably, the ultrasonic power is 800 W, the temperature is 25° C., and the ultrasonic time is 4 h.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention provides an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials can reduce fomesafen residues in soybean field soil by in-situ enhanced reduction in the rhizosphere, which rapidly reduces the concentration of fomesafen in the soil, avoids competition with indigenous microorganisms, and ensures the restoration effect.

[0022] 2. The method for reducing fomesafen residues in soybean field soil provided by the present invention is easy to operate, simple and easy to implement, and has low cost. Through the regulatory effect of Fe3O4NMs on soybean rhizosphere metabolites, the abundance of core species and potential degrading bacteria in the rhizosphere microbial community is effectively increased, the synergistic interaction between bacterial species is enhanced, and the rhizosphere reduction of fomesafen is promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The in-situ enhanced reduction effect of Example 1 and Comparative Example 1 on fomesafen residues, CK represents the control treatment without basal application of Fe3O4 NMs; F represents the treatment with basal application of Fe3O4 NMs;

[0024] Figure 2 The differential metabolites, fomesafen reduction rate, and the symbiotic network of core microorganisms and potential degrading bacteria of Example 1; FSAR: fomesafen reduction rate. DETAILED DESCRIPTION

[0025] The following will be combined with the specific implementation of the present invention to clearly and completely describe the technical solution in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0027] The rhizosphere is an important microenvironment for the biotransformation of pollutants. Enhanced rhizosphere reduction is more in line with the actual situation of farmland soil and is more conducive to the reduction of herbicide residues in farmland soil. Utilizing the synergistic symbiotic relationship between microbiome and plants can make the remediation process more efficient and reduce input costs, but there is still a lack of green and efficient rhizosphere in-situ enhanced reduction technology for soil with flufenacet residues. After research, the present invention uses iron-containing nanomaterials to perform in-situ enhanced rhizosphere reduction of flufenacet residues in soybean field soil. After 15 days of treatment, the residual concentration of flufenacet in soybean field soil can be reduced to 1.62 mg kg -1 , the reduction rate reached 38.05%. After 25 days, the residual concentration of fomesafen was further reduced, and the reduction rate reached 43.79%.

[0028] The nano-ferroferric oxide in the present invention is purchased from Shanghai Shuitian Material Technology Co., Ltd. and is abbreviated as Fe3O4NMs.

[0029] Example 1

[0030] The test soil was collected from farmland cultivated for many years in Hailun City, Heilongjiang Province, the test soybean variety was Dongsheng 22, and the test nanomaterial was nano-ferric oxide with a particle size of 20nm and a purity of 99.9%. Nano-ferric oxide was used to enhance the reduction of fomesafen in the soybean rhizosphere.

[0031] The invention discloses an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials are nano-ferroferric oxide, and the fomesafen residues are fomesafen residues in soybean field soil.

[0032] The particle size of the nano-ferroferric oxide is 10nm-30nm, and the purity is 99.9%.

[0033] A method for reducing fomesafen residues in soybean field soil, the specific implementation steps are:

[0034] The fomesafen aqueous solution was dissolved in acetone. Based on the uniform distribution of fomesafen in the soil, this embodiment adopted a stepwise dilution method to prepare a theoretical concentration of 3.00 mg kg -1 Urea, calcium dihydrogen phosphate and potassium sulfate were mixed into the soil as base fertilizer, so that the N, P and K contents were 0.06 g kg -1 , 0.06g·kg -1 , 0.08g·kg -1 Then, 3.00 mg kg -1The fomesafen-contaminated soil was placed in a flowerpot, with a soil mass of 1.8 kg per pot. Deionized water was added to adjust the water content to 30%, w / w. Soybean seeds of uniform size were selected and sterilized in a 70% alcohol solution for 10 seconds. After being taken out, they were rinsed three times with sterilized distilled water and dried aseptically for later use. Filter paper was placed in a plastic culture dish, and the soybean seeds were evenly placed in the plastic culture dish. Ultrapure water was added to cover the soybean seeds, and the lid was closed and placed in a constant temperature incubator at 28°C to start germination. Water was added four times during the period, and each time the water surface was added to cover the soybean seeds. The soybeans were transplanted into pots after germination for 24 hours. Six soybeans were planted in each pot, and the number of seedlings was thinned to 3 after germination. The flowerpots were placed in a constant temperature and light room at 25°C. The actual concentration of fomesafen in potted plants was 2.65 mg·kg -1 .

[0035] Preparation of Fe3O4 NMs suspension: Add 15 mg Fe3O4 NMs to 500 mL ultrapure water, and use an ultrasonic cleaner at 800 W and 25 ° C for 1 hour to make a uniform and stable suspension with a concentration of 30 mg / L, which is used as a mother solution. Take out 100 mL of the mother solution and dilute it to 400 mL to form a uniform and stable suspension with a concentration of 7.5 mg / L, which is used as a mother solution. Since it is not easy to directly prepare a Fe3O4 NMs suspension with a concentration of 7.5 mg / L by ultrasonic uniformity, it is done step by step here.

[0036] Fe3O4 NMs suspension was applied on the 40th day after soybean planting. Each pot was irrigated with 100 mL of Fe3O4 NMs suspension at 8:00 a.m., once a day. After 5 consecutive days of irrigating, the Fe3O4 NMs concentration in the soil was 2.08 mg kg -1 On the 55th day after sowing, i.e. 15 days after treatment, and the 65th day after treatment, samples were taken to measure the concentration of fomesafen in the rhizosphere soil.

[0037] Example 2

[0038] The test soil was collected from farmland cultivated for many years in Hailun City, Heilongjiang Province, the test soybean variety was Dongsheng 22, and the test nanomaterial was nano-ferric oxide with a particle size of 10nm and a purity of 99.9%. Nano-ferric oxide was used to enhance the reduction of fomesafen in the soybean rhizosphere.

[0039] The invention discloses an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials are nano-ferroferric oxide, and the fomesafen residues are fomesafen residues in soybean field soil.

[0040] The particle size of the nano-ferroferric oxide is 10nm-30nm, and the purity is 99.9%.

[0041] A method for reducing fomesafen residues in soybean field soil, the specific implementation steps are:

[0042] The fomesafen aqueous solution was dissolved in acetone. Based on the uniform distribution of fomesafen in the soil, this embodiment adopted a stepwise dilution method to prepare a theoretical concentration of 3.00 mg kg -1 Urea, calcium dihydrogen phosphate and potassium sulfate were mixed into the soil as base fertilizer, so that the N, P and K contents were 0.06 g kg -1 , 0.06g·kg -1 , 0.08g·kg -1 Then, 3.00 mg kg -1 The fomesafen-contaminated soil was placed in a flowerpot, with a soil mass of 1.8 kg per pot. Deionized water was added to adjust the water content to 30%, w / w. Soybean seeds of uniform size were selected and sterilized in a 70% alcohol solution for 10 seconds. After being taken out, they were rinsed three times with sterilized distilled water and dried aseptically for later use. Filter paper was placed in a plastic culture dish, and the soybean seeds were evenly placed in the plastic culture dish. Ultrapure water was added to cover the soybean seeds, and the lid was closed and placed in an oven to start germination. During this period, water was added four times, and each time the water surface was added to cover the soybean seeds. The soybeans were transplanted into pots after germination for 24 hours. Six soybeans were planted in each pot, and the number of seedlings was thinned to 3 after emergence. The pots were placed in a constant temperature and light room at 25°C. The actual concentration of fomesafen in potted plants is 2.65 mg·kg -1 .

[0043] Preparation of Fe3O4 NMs suspension: Add 15 mg Fe3O4 NMs to 500 mL ultrapure water, and use an ultrasonic cleaner at 800 W and 25 ° C for 1 hour to make a uniform and stable suspension with a concentration of 30 mg / L, which is used as a mother solution for standby use. Take out 100 mL of the mother solution and dilute it to 600 mL to form a uniform and stable suspension with a concentration of 5 mg / L, which is used for standby use. Since it is not easy to ultrasonically uniformly prepare a Fe3O4 NMs suspension with a concentration of 5 mg / L directly, it is done step by step here.

[0044] Fe3O4 NMs suspension was applied on the 40th day after soybean planting. 90 mL of Fe3O4 NMs suspension was poured into each pot at 8:00 a.m., once a day. After 5 consecutive days of watering, the Fe3O4 NMs concentration in the soil was 1.25 mg kg -1 On the 55th day after sowing, i.e. 15 days after treatment, and the 65th day after treatment, samples were taken to measure the concentration of fomesafen in the rhizosphere soil.

[0045] Example 3

[0046] The test soil was collected from farmland cultivated for many years in Hailun City, Heilongjiang Province, the test soybean variety was Dongsheng 22, and the test nanomaterial was nano-ferric oxide with a particle size of 10nm and a purity of 99.9%. Nano-ferric oxide was used to enhance the reduction of fomesafen in the soybean rhizosphere.

[0047] The invention discloses an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials are nano-ferroferric oxide, and the fomesafen residues are fomesafen residues in soybean field soil.

[0048] The particle size of the nano-ferroferric oxide is 10nm-30nm, and the purity is 99.9%.

[0049] A method for reducing fomesafen residues in soybean field soil, the specific implementation steps are:

[0050] The fomesafen aqueous solution was dissolved in acetone. Based on the uniform distribution of fomesafen in the soil, this embodiment adopted a stepwise dilution method to prepare a theoretical concentration of 3.00 mg kg -1 Urea, calcium dihydrogen phosphate and potassium sulfate were mixed into the soil as base fertilizer, so that the N, P and K contents were 0.06 g kg -1 , 0.06g·kg -1 , 0.08g·kg -1 Then, 3.00 mg kg -1 The fomesafen-contaminated soil was placed in a flowerpot, with a soil mass of 1.8 kg per pot. Deionized water was added to adjust the water content to 30%, w / w. Soybean seeds of uniform size were selected and sterilized in a 70% alcohol solution for 10 seconds. After being taken out, they were rinsed three times with sterilized distilled water and dried aseptically for later use. Filter paper was placed in a plastic culture dish, and the soybean seeds were evenly placed in the plastic culture dish. Ultrapure water was added to cover the soybean seeds, and the lid was closed and placed in an oven to start germination. During this period, water was added four times, and each time the water surface was added to cover the soybean seeds. The soybeans were transplanted into pots after germination for 24 hours. Six soybeans were planted in each pot, and the number of seedlings was thinned to 3 after emergence. The pots were placed in a constant temperature and light room at 25°C. The actual concentration of fomesafen in potted plants is 2.65 mg·kg -1 .

[0051] Preparation of Fe3O4 NMs suspension: Add 15 mg Fe3O4 NMs to 500 mL ultrapure water, and use an ultrasonic cleaner at 800 W and 25 ° C for 1 to 4 hours to make a uniform and stable suspension with a concentration of 30 mg / L, which is used as a mother solution. Take out 100 mL of the mother solution and dilute it to 375 mL to form a uniform and stable suspension with a concentration of 8 mg / L, which is used as a mother solution. Since it is not easy to directly prepare a Fe3O4 NMs suspension with a concentration of 8 mg / L by ultrasonic uniformity, it is done step by step here.

[0052] Fe3O4 NMs suspension was applied on the 45th day after soybean planting. Each pot was irrigated with 144 mL of Fe3O4 NMs suspension at 9:00 a.m., once a day. After 6 consecutive days of irrigating, the Fe3O4 NMs concentration in the soil was 3.84 mg kg -1 On the 55th day after sowing, i.e. 15 days after treatment, and the 65th day after treatment, samples were taken to measure the concentration of fomesafen in the rhizosphere soil.

[0053] Example 4

[0054] The test soil was collected from farmland cultivated for many years in Hailun City, Heilongjiang Province, the test soybean variety was Dongsheng 22, and the test nanomaterial was nano-ferric oxide with a particle size of 30nm and a purity of 99.9%. Nano-ferric oxide was used to enhance the reduction of fomesafen in the soybean rhizosphere.

[0055] The invention discloses an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials are nano-ferroferric oxide, and the fomesafen residues are fomesafen residues in soybean field soil.

[0056] The particle size of the nano-ferroferric oxide is 10nm-30nm, and the purity is 99.9%.

[0057] A method for reducing fomesafen residues in soybean field soil, the specific implementation steps are:

[0058] The fomesafen aqueous solution was dissolved in acetone. Based on the uniform distribution of fomesafen in the soil, this embodiment adopted a stepwise dilution method to prepare a theoretical concentration of 3.00 mg kg -1 Urea, calcium dihydrogen phosphate and potassium sulfate were mixed into the soil as base fertilizer, so that the N, P and K contents were 0.06 g kg -1 , 0.06g·kg -1 , 0.08g·kg -1 Then, 3.00 mg kg -1The fomesafen-contaminated soil was placed in a flowerpot, with a soil mass of 1.8 kg per pot. Deionized water was added to adjust the water content to 30%, w / w. Soybean seeds of uniform size were selected and sterilized in a 70% alcohol solution for 10 seconds. After being taken out, they were rinsed three times with sterilized distilled water and dried aseptically for later use. Filter paper was placed in a plastic culture dish, and the soybean seeds were evenly placed in the plastic culture dish. Ultrapure water was added to cover the soybean seeds, and the lid was closed and placed in an oven to start germination. During this period, water was added four times, and each time the water surface was added to cover the soybean seeds. The soybeans were transplanted into pots after germination for 24 hours. Six soybeans were planted in each pot, and the number of seedlings was thinned to 3 after emergence. The pots were placed in a constant temperature and light room at 25°C. The actual concentration of fomesafen in potted plants is 2.65 mg·kg -1 .

[0059] Preparation of Fe3O4 NMs suspension: Add 15 mg Fe3O4 NMs to 500 mL ultrapure water, and use an ultrasonic cleaner at 800 W and 25 ° C for 3 hours to make a uniform and stable suspension with a concentration of 30 mg / L, which is used as a mother solution. Take out 100 mL of the mother solution and dilute it to 333.33 mL to form a uniform and stable suspension with a concentration of 9 mg / L, which is used as a mother solution. Since it is not easy to directly prepare a Fe3O4 NMs suspension with a concentration of 9 mg / L by ultrasonic uniformity, it is done step by step here.

[0060] Fe3O4 NMs suspension was applied on the 50th day after soybean planting. Each pot was irrigated with 144 mL of Fe3O4 NMs suspension at 11:00 a.m., once a day. After 6 consecutive days of irrigating, the Fe3O4 NMs concentration in the soil was 4.32 mg kg -1 On the 55th day after sowing, i.e. 15 days after treatment, and the 65th day after treatment, samples were taken to measure the concentration of fomesafen in the rhizosphere soil.

[0061] Example 5

[0062] The test soil was collected from farmland cultivated for many years in Hailun City, Heilongjiang Province, the test soybean variety was Dongsheng 22, and the test nanomaterial was nano-ferric oxide with a particle size of 30nm and a purity of 99.9%. Nano-ferric oxide was used to enhance the reduction of fomesafen in the soybean rhizosphere.

[0063] The invention discloses an application of iron-containing nanomaterials in reducing fomesafen residues. The iron-containing nanomaterials are nano-ferroferric oxide, and the fomesafen residues are fomesafen residues in soybean field soil.

[0064] The particle size of the nano-ferroferric oxide is 10nm-30nm, and the purity is 99.9%.

[0065] A method for reducing fomesafen residues in soybean field soil, the specific implementation steps are:

[0066] The fomesafen aqueous solution was dissolved in acetone. Based on the uniform distribution of fomesafen in the soil, this embodiment adopted a stepwise dilution method to prepare a theoretical concentration of 3.00 mg kg -1 Urea, calcium dihydrogen phosphate and potassium sulfate were mixed into the soil as base fertilizer, so that the N, P and K contents were 0.06 g kg -1 , 0.06g·kg -1 , 0.08g·kg -1 Then, 3.00 mg kg -1 The fomesafen-contaminated soil was placed in a flowerpot, with a soil mass of 1.8 kg per pot. Deionized water was added to adjust the water content to 30%, w / w. Soybean seeds of uniform size were selected and sterilized in a 70% alcohol solution for 10 seconds. After being taken out, they were rinsed three times with sterilized distilled water and dried aseptically for later use. Filter paper was placed in a plastic culture dish, and the soybean seeds were evenly placed in the plastic culture dish. Ultrapure water was added to cover the soybean seeds, and the lid was closed and placed in an oven to start germination. During this period, water was added four times, and each time the water surface was added to cover the soybean seeds. The soybeans were transplanted into pots after germination for 24 hours. Six soybeans were planted in each pot, and the number of seedlings was thinned to 3 after emergence. The pots were placed in a constant temperature and light room at 25°C. The actual concentration of fomesafen in potted plants is 2.65 mg·kg -1 .

[0067] Preparation of Fe3O4 NMs suspension: Add 15 mg Fe3O4 NMs to 500 mL ultrapure water, and use an ultrasonic cleaner at 800 W and 25 ° C for 4 hours to make a uniform and stable suspension with a concentration of 30 mg / L, which is used as a mother solution for standby use. Take out 100 mL of the mother solution and dilute it to 300 mL to form a uniform and stable suspension with a concentration of 10 mg / L, which is used for standby use. Since it is not easy to ultrasonically uniformly prepare a Fe3O4 NMs suspension with a concentration of 10 mg / L directly, it is done step by step here.

[0068] Fe3O4 NMs suspension was applied on the 50th day after soybean planting. Each pot was irrigated with 144 mL of Fe3O4 NMs suspension at 12:00 am. The watering was continued once a day for 6 consecutive days, so that the Fe3O4 NMs concentration in the soil was 4.80 mg kg -1 On the 55th day after sowing, i.e. 15 days after treatment, and the 65th day after treatment, samples were taken to measure the concentration of fomesafen in the rhizosphere soil.

[0069] Comparative Example 1

[0070] The only difference from Example 1 is that soybeans were planted in the residual soil but no Fe3O4 NMs were applied.

[0071] The test soil was collected from farmland cultivated for many years in Hailun City, Heilongjiang Province, and the test soybean variety was Dongsheng 22.

[0072] Dissolve the fomesafen aqueous solution in acetone and prepare a theoretical concentration of 3.00 mg kg by stepwise dilution. -1 Urea, calcium dihydrogen phosphate and potassium sulfate were mixed into the soil as base fertilizer, so that the N, P and K contents were 0.06 g kg -1 , 0.06g·kg -1 , 0.08g·kg -1 Then, 3.00 mg kg -1 The fomesafen-contaminated soil was placed in a flowerpot, with a soil mass of 1.8 kg per pot. Deionized water was added to adjust the moisture content to 30%, w / w. Soybean seeds of uniform size were selected and sterilized in a 70% alcohol solution for 10 seconds. After being taken out, they were rinsed three times with sterilized distilled water and dried aseptically for later use. Filter paper was placed in a plastic culture dish, and the soybean seeds were evenly placed in the plastic culture dish. Ultrapure water was added to cover the soybean seeds, and the lid was closed and placed in an oven to start germination. Water was added four times during the period. The soybeans were transplanted into pots after germination for 24 hours. Six soybeans were planted in each pot, and the number of seedlings was thinned to 3 after emergence. The flowerpots were placed in a constant temperature and light room at 25°C. The actual concentration of fomesafen in potted plants was 2.65 mg·kg -1 .

[0073] Samples were taken on the 15th and 25th days after sowing to measure the concentration of fomesafen in the rhizosphere soil.

[0074] Since the reduction rate of fomesafen in the soil of Examples 2 to 5 was between 38.0% and 38.05% after 15 days, and the reduction rate of fomesafen in the soil was between 43.62% and 43.79% after 25 days, only the reduction rate of fomesafen in the soil of Example 1 is plotted below.

[0075] like Figure 1 As shown in Figure 1, after 15 days, the residual concentration of fomesafen in the soil of Comparative Example 1 was 1.88 mg kg -1 The reduction rate was only 27.98%, and the residual concentration of fomesafen in the soil of Comparative Example 1 after 25 days was 1.66 mg kg -1 The reduction rate was 33.91%. This showed that when soybean was planted without basal application of Fe3O4 NMs, the reduction of fomesafen in the soil was limited.

[0076] like Figure 1 As shown, Figure 1The in-situ enhanced reduction effect of Example 1 and Comparative Example 1 on fomesafen residues. CK represents the control treatment without basal application of Fe3O4 NMs; F represents the treatment with basal application of Fe3O4 NMs. After 15 days of treatment, the residual concentration of fomesafen in the soil of Example 1 was 1.62 mg kg -1 , the reduction rate reached 38.05%, which was 10.07% higher than that of Example 1 in which only soybeans were planted; after 25 days, the residual concentration of fomesafen further decreased, and the reduction rate reached 43.79%, while the reduction rate of the control was only 33.91%, indicating that the application of Fe3O4NMs irrigation suspension can significantly promote the rhizosphere reduction of fomesafen.

[0077] Figure 2 The symbiotic network of differential metabolites, fomesafen reduction rate, core microorganisms and potential degrading bacteria in Example 1; FSAR: fomesafen reduction rate. The complex relationship between 30 differential metabolites, core microorganisms, potential degrading bacteria and fomesafen rhizosphere reduction rate that were significantly changed by applying Fe3O4NMs was analyzed using the symbiotic network. The results showed that the key differential metabolites and microorganisms were mainly positively correlated. Compared with potential degrading bacteria, the number of connection edges between metabolites and core microorganisms was more, indicating that the potential interaction between metabolites and core microorganisms was stronger. In addition, among many bacterial genera, Novosphingobium, Pedobacter, Pirellula, Altererythrobacter, Thermomonas, and Stenotrophomonas had stronger potential interactions with metabolites, indicating that these bacterial genera played a more important role in the reduction process of fomesafen. In the core microbial interactions, the number of positive and negative connections was comparable, indicating that the antagonism and synergy between the core microorganisms were relatively balanced. There are mostly positive connections between core microorganisms and potential degraders, as well as within potential degraders, which means that the synergy between these microorganisms is stronger. Therefore, Fe3O4 NMs may promote the secretion of some specific rhizosphere metabolites, thereby regulating the core microorganisms and potential degraders in the rhizosphere microbial community, enhancing the synergy between core microorganisms and potential degraders, and ultimately promoting the rhizosphere reduction of fomesafen.

[0078] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0079] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. Application of iron-containing nanomaterials in reducing fomesafen residues, characterized in that: The iron-containing nano material is nano ferrosoferric oxide, and the fomesafen residue is the fomesafen residue in soybean field soil.

2. The use of the iron-containing nanomaterial in reducing fomesafen residues according to claim 1, characterized in that: The particle size of the nano-ferroferric oxide is 10nm-30nm.

3. A method for reducing fomesafen residues in soybean field soil, characterized in that: The specific steps include: The iron-containing nanomaterial according to claim 1 is used to prepare an iron-containing nanosuspension, wherein the concentration of the iron-containing nanosuspension is 5 mg / L-10 mg / L; Soybeans are planted in the soil containing fomesafen residues, and the iron-containing nanosuspension is irrigated onto the roots of the soybeans 40 to 50 days after the soybeans are planted.

4. The method for reducing fomesafen residues in soybean field soil according to claim 3, characterized in that: When the iron-containing nano suspension is a nano ferroferric oxide suspension, the particle size of the nano ferroferric oxide is 10nm-30nm, and the purity is 99.9%.

5. The method for reducing fomesafen residues in soybean field soil according to claim 4, characterized in that: The irrigation amount of the nano-ferroferric oxide suspension is: 50 mL-80 mL of the nano-ferroferric oxide suspension is irrigated per kg of fomesafen residual soil.

6. The method for reducing fomesafen residues in soybean field soil according to claim 5, characterized in that: The nano-ferroferric oxide suspension is watered once a day for 5 to 6 consecutive days.

7. The method for reducing fomesafen residues in soybean field soil according to claim 6, characterized in that: After continuous irrigation for 5 to 6 days, the concentration of nano-ferroferric oxide in the soybean field soil was 1.25 mg kg -1 ~4.80mg·kg -1 .

8. The method for reducing fomesafen residues in soybean field soil according to claim 7, characterized in that: The specific method for preparing the nano-ferroferric oxide suspension is as follows: dispersing the nano-ferroferric oxide in water, and obtaining the nano-ferroferric oxide irrigation suspension with a concentration of 5 mg / L-10 mg / L after ultrasonic treatment.

9. The method for reducing fomesafen residues in soybean field soil according to claim 8, characterized in that: The ultrasonic power is 800W-1000W, the temperature is 20°C-25°C, and the ultrasonic time is 1h-4h.

10. The method for reducing fomesafen residues in soybean field soil according to claim 9, characterized in that: The ultrasonic power is 800W, the temperature is 25°C, and the ultrasonic time is 4h.

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