Rare earth modified nano material and application thereof in prevention and treatment of cotton verticillium wilt

Abstract

The invention provides a rare earth modified nano material and application thereof in prevention and treatment of cotton verticillium wilt, the rare earth modified nano material is prepared from modified rare earth chloride RE-Na and calcium oxide, and the modified rare earth chloride RE-Na is prepared by modifying rare earth chloride with sodium benzoate. The rare earth material used in the rare earth modified nano material RE (at) DL prepared by the invention is sodium benzoate modified rare earth chloride, and compared with single use of rare earth oxide, benzoic acid in the modified rare earth chloride can generate ionization action in fungal cells, so that alkali storage (such as NaHCO3 and the like) in the cells is acidified, and the fungal cells can be degraded. The acidification effect can change the pH value in the cells, so that the activity of respiratory enzyme systems in fungal cells is inhibited, and fungi are killed.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and in particular relates to a rare earth modified nano material and application thereof in the prevention and treatment of cotton Verticillium wilt. Background Art

[0002] Cotton Verticillium wilt, caused by Verticillium dahliae, is a global disease that has spread across my country in recent years, particularly in major cotton-producing areas like Xinjiang, becoming a major obstacle to cotton production. The disease is primarily soil-borne, infecting the cotton plant's vascular system, causing leaves to turn yellow, wither, and fall off. In severe cases, it can even lead to plant death. The onset of cotton Verticillium wilt is closely related to the resistance of the cotton variety, the pathogenicity of the pathogen, and environmental conditions. Therefore, its prevention and control remains a key issue in cotton production.

[0003] The pathogenic mechanism of cotton Verticillium wilt is complex, with two main theories: the blockage theory and the toxin theory. The blockage theory posits that the pathogen's hyphae and spores proliferate in large numbers within the cotton plant's ducts, blocking them and impeding water and nutrient transport, leading to plant wilt. The toxin theory, on the other hand, suggests that toxins produced by the pathogen damage cotton plant cells, causing cell death and plant wilt. Regardless of the mechanism, cotton Verticillium wilt has a serious impact on cotton growth and yield. Traditional methods for controlling cotton Verticillium wilt include agricultural control, chemical control, and biological control. Agricultural control primarily involves measures such as appropriate crop rotation, deep plowing and land preparation, cleaning cotton fields, and increasing the application of organic fertilizers to reduce the pathogen's presence in the soil and enhance cotton plant resistance. Chemical control primarily relies on the use of fungicides such as methyl bromide, ethylene dibromide, and chloramphenicol. However, these chemicals are not only costly and environmentally polluting, but long-term use can also lead to the development of antibiotic resistance in pathogens. Biological control mainly uses natural substances such as microorganisms and plant extracts to induce disease resistance in cotton plants, but the effect of this method is often unstable and takes a long time to appear.

[0004] In recent years, with the rapid development of nanotechnology, the application of nanomaterials in agriculture has gradually attracted attention. As a new type of functional material, rare earth-modified nanomaterials, due to their unique physical and chemical properties, show great potential in agricultural pest control. Rare earth elements have a variety of biological effects, such as improving plant resistance, promoting growth and development, and improving plant quality. Combining rare earth elements with nanomaterials can further enhance their biological activity and improve control effectiveness. In the control of cotton Verticillium wilt, the application principles of rare earth-modified nanomaterials are mainly based on the following aspects: first, rare earth elements can affect the growth and reproduction of pathogens, inhibiting their pathogenicity; second, rare earth-modified nanomaterials can improve the soil microenvironment, promote the growth of beneficial microorganisms, and inhibit the spread of pathogens; third, rare earth elements can enhance the disease resistance of cotton plants, improving their resistance to Verticillium wilt.

[0005] Research has shown that treating cotton seeds with a rare earth solution at an appropriate concentration can significantly improve the plant's disease resistance and yield. For example, treating cotton seeds with a 300mg / kg rare earth solution significantly reduced the incidence and disease index of Verticillium wilt, improving the plant's disease resistance. Furthermore, rare earth treatment significantly improved growth indicators such as cotton plant emergence rate, root fresh weight, stem length, stem fresh weight, stem weight, and boll number, thereby increasing cotton yield. Furthermore, rare earth-modified nanomaterials can further enhance cotton plant disease resistance by affecting physiological and biochemical processes such as respiration, photosynthesis, phenylalanine ammonia lyase (PAL) activity, and protein content. These changes in physiological and biochemical processes not only improve the plant's resistance to pathogens but also promote its growth and development, improving cotton yield and quality.

[0006] In summary, the application of rare earth-modified nanomaterials in the prevention and control of cotton Verticillium wilt has broad prospects. By in-depth research on the biological effects and mechanisms of action of rare earth-modified nanomaterials and optimizing their preparation and application technologies, it is expected that a new, efficient, and environmentally friendly method for the prevention and control of cotton Verticillium wilt will be provided, promoting the sustainable development of cotton production in my country. Summary of the Invention

[0007] In view of this, the present invention aims to overcome the defects in the prior art and proposes a rare earth modified nanomaterial and its application in the prevention and treatment of cotton Verticillium wilt.

[0008] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0009] In a first aspect, a rare earth modified nanomaterial RE@DL is provided. The rare earth modified nanomaterial RE@DL is prepared from modified rare earth chloride RE-Na and calcium oxide. The modified rare earth chloride RE-Na is prepared by modifying rare earth chloride with sodium benzoate.

[0010] Preferably, the rare earth chloride is a mixture of one or more of lanthanum chloride, cerium chloride and yttrium chloride.

[0011] Preferably, the mass ratio of sodium benzoate to rare earth chloride is (1-3):(3-5).

[0012] Preferably, the solid mass ratio of the modified rare earth chloride RE-Na to calcium oxide is (3-5): (1-2).

[0013] Furthermore, the preparation method of the modified rare earth chloride RE-Na is:

[0014] After adding rare earth chloride into sodium benzoate aqueous solution, stirring and mixing at a temperature of 55-65° C., a hydrothermal reaction is carried out, and the reaction product is dried and ground to obtain modified rare earth chloride RE-Na.

[0015] Preferably, the mass concentration of the sodium benzoate solution is 30-100 g / L.

[0016] Preferably, the temperature of the hydrothermal reaction is 120° C.-150° C., and the reaction time is 6 h-8 h.

[0017] Preferably, the drying temperature is 80° C.-100° C., and the drying time is 36-48 hours.

[0018] In a second aspect, the present invention further provides a method for preparing the rare earth modified nanomaterial RE@DL, comprising the following steps:

[0019] After deionized water reacts with calcium oxide, modified rare earth chloride RE-Na is added thereto. After thorough stirring, the reaction liquid is transferred to an oven and dried to a powder state, and then transferred to a muffle furnace for calcination. The calcined powder is wet sand milled and vacuum dried to obtain rare earth modified nanomaterial RE@DL.

[0020] Preferably, the input amount of calcium oxide is 23-53 g / L per liter of deionized water.

[0021] Preferably, the mass concentration of the modified rare earth chloride in the mixed system of calcium hydroxide and deionized water is 110-150 g / L.

[0022] Preferably, the drying conditions are: 80-100° C. for 36-48 hours.

[0023] Preferably, the calcination conditions are: calcination at 500-700° C. for 4-6 hours.

[0024] Preferably, the wet sand milling is performed in a sand mill at 3500-4000 r / min for 4.0-6.0 h.

[0025] Preferably, the average particle size of the rare earth modified nanomaterial RE@DL is 70-100 nm.

[0026] In a third aspect, the present invention further provides the use of the rare earth modified nanomaterial RE@DL in the preparation of a biocontrol agent for inhibiting Verticillium dahliae.

[0027] In a fourth aspect, the present invention provides the use of the rare earth modified nanomaterial RE@DL in the preparation of a biological control agent for cotton Verticillium wilt.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The rare earth material used in the rare earth modified nanomaterial RE@DL prepared by the present invention is a rare earth chloride modified with sodium benzoate. Compared with the use of rare earth oxide alone, the benzoic acid in the modified rare earth chloride will produce ionization in the fungal cells, causing the alkaline storage (such as NaHCO3, etc.) in the cells to be acidified. This acidification will change the pH value in the cells, thereby inhibiting the activity of the respiratory enzyme system in the fungal cells and killing the fungi. In addition, the rare earth modified nanomaterial RE@DL contains calcium hydroxide. The hydroxyl ions released by calcium hydroxide when it comes into contact with water have strong oxidizing properties and can react with the phospholipid bilayer in the fungal cell membrane, causing the cell membrane to rupture and destroying the integrity of the bacterial structure. In addition, after entering the cell, the hydroxyl group can also cause the breakage of the intracellular DNA bond. In summary, in addition to the antibacterial properties of the rare earth ions themselves, the rare earth modified nanomaterial RE@DL in the present invention also has the antibacterial ability of sodium benzoate and calcium hydroxide. The three are superimposed and complement each other to exert a strong antibacterial effect.

[0030] (2) The raw materials used to modify the rare earths in this invention are rare earth chlorides, which are inexpensive and easy to mass-produce. Furthermore, the rare earth-modified nanomaterial RE@DL is a nanoscale antibacterial material. Nanomaterials themselves possess improved dispersibility and antibacterial properties, thus further enhancing the material's ability to inhibit Verticillium dahliae by utilizing the small size effect. Furthermore, my country's soil faces a serious acidification problem. This alkaline material, when applied to the soil, can kill Verticillium dahliae while improving acidic soils, providing a favorable soil environment for the next crop rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram showing the antibacterial effect of different rare earth modified nanomaterials RE@DL on Verticillium dahliae. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0033] Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0034] Where values ​​are described herein as ranges, it should be understood that such disclosure includes disclosure of all possible sub-ranges within that range, as well as specific values ​​falling within that range, regardless of whether a specific value or sub-range is explicitly stated.

[0035] In this document, "a plurality of" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0036] In this document, the terms “preferably” and “more preferably” are only used to describe implementation methods or examples with better effects. It should be understood that they do not limit the scope of protection of the present invention.

[0037] In this document, the word "further" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present invention.

[0038] In this article, the term "and / or" is used to describe the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0039] As used herein, the term "about" means + / - 10%, preferably + / - 5%, more preferably + / - 1% of the specified value.

[0040] In this document, the terms “include,” “including,” “have,” “contain,” etc. are open-ended terms, meaning including but not limited to.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0042] The present invention will be described in detail below with reference to the embodiments.

[0043] Example 1

[0044] (1) Preparation of modified rare earth chloride (La-Na)

[0045] First, add 100g of sodium benzoate powder and 2.0L of deionized water to a measuring cup. Place the mixture in a magnetic stirrer, heat to 60°C, and begin stirring. Add a rotor and set the speed to 600r / min. After reacting for 1.5 hours, the mixture is completely dissolved to obtain a sodium benzoate solution. Add 200g of lanthanum chloride to the above solution and continue stirring until completely dissolved. Transfer the mixture to a hydrothermal reactor and react at 150°C for 7 hours. After that, pour it into an evaporating dish and transfer it to an oven set to 90°C for 48 hours. After drying, grind the solid to obtain the modified rare earth chloride La-Na.

[0046] (2) Preparation of rare earth modified nanomaterials La@DL

[0047] To a measuring cup, add 1.0L of deionized water and 50g of calcium oxide, stir thoroughly, then add 130g of modified rare earth chloride (La-Na). Stir thoroughly with a glass rod, let the reaction stand for a while, and once the reaction solution stabilizes, transfer it to an oven at 90°C for 48 hours. Dry it to a powder, grind it gently, and then calcine it in a muffle furnace at 600°C for 5 hours. Weigh 100g of the calcined powder and add it to 400mL of deionized water. Add 25mL of 2800 dispersant and 5mL of silicone defoamer, then sand grind it in a horizontal sand mill at 3700 rpm for 5 hours. After sand grinding to a particle size of less than 100nm, transfer the slurry to a vacuum drying oven and dry it under vacuum for 48 hours to obtain the rare earth-modified nanomaterial La@DL.

[0048] Example 2

[0049] (1) Preparation of modified rare earth chloride (Ce-Na)

[0050] First, add 30g of sodium benzoate powder and 1L of deionized water to a measuring cup. Place the mixture in a magnetic stirrer, heat to 55°C, and begin stirring. Add a rotor and set the speed to 600 rpm. After 1.5 hours of reaction, completely dissolve the sodium benzoate solution. Add 150g of cerium chloride to the above solution and continue stirring until completely dissolved. Transfer the mixture to a hydrothermal reactor and react at 120°C for 8 hours. Afterwards, pour the mixture into an evaporating dish and transfer it to an oven set to 80°C for 48 hours. After drying, grind the solid to obtain the modified rare earth chloride Ce-Na.

[0051] (2) Preparation of rare earth complex (Ce@DL)

[0052] In a measuring cup, 1.0L of deionized water and 23g of calcium oxide were stirred thoroughly. After the reaction, 110g of modified rare earth chloride (Ce-Na) was added. The reaction was stirred thoroughly with a glass rod and allowed to stand for a short while. Once the reaction solution stabilized, it was transferred to an oven at 100°C for 36 hours. After drying to a powdery consistency, the mixture was ground gently and then calcined in a muffle furnace at 700°C for 4 hours. 100g of the calcined powder was weighed and added to 400mL of deionized water. 25mL of 2800 dispersant and 5mL of silicone defoamer were added, followed by sand milling in a horizontal sand mill at 4000 rpm for 4.0 hours. After sand milling to a particle size of less than 100nm, the slurry was transferred to a vacuum drying oven and dried under vacuum for 48 hours to obtain the rare earth-modified nanomaterial Ce@DL.

[0053] Example 3

[0054] (1) Preparation of modified rare earth chloride (Y-Na)

[0055] First, add 100g of sodium benzoate powder and 1L of deionized water to a measuring cup. Place the mixture in a magnetic stirrer, heat to 65°C, and begin stirring. Add a rotor and set the speed to 600 rpm. Allow to react for 1.5 hours until the mixture is completely dissolved, yielding a sodium benzoate solution. Add 100g of yttrium chloride to the solution and continue stirring until completely dissolved. Transfer the mixture to a hydrothermal reactor and react at 150°C for 6 hours. Pour the mixture into an evaporating dish and transfer it to an oven set to 100°C for 36 hours. Grind the dried solid to obtain the modified rare earth chloride Y-Na.

[0056] (2) Preparation of rare earth complexes (Y@DL)

[0057] In a measuring cup, 1.0L of deionized water and 53g of calcium oxide were stirred thoroughly. After the reaction, 150g of modified rare earth chloride (Y-Na) was added. The reaction was stirred thoroughly with a glass rod and allowed to stand for a while. Once the reaction solution stabilized, it was transferred to an oven at 80°C for 48 hours. After drying to a powdery consistency, the mixture was ground gently and then calcined in a muffle furnace at 500°C for 6 hours. 100g of the calcined powder was weighed and added to 400mL of deionized water. 25mL of 2800 dispersant and 5mL of silicone defoamer were added, followed by sand milling in a horizontal sand mill at 3500 rpm for 6 hours. After sand milling to a particle size of less than 100nm, the slurry was transferred to a vacuum drying oven and dried under vacuum for 48 hours to obtain the rare earth-modified nanomaterial Y@DL.

[0058] Comparative Example 1

[0059] The modified rare earth oxides in Examples 1 to 3 were replaced with unmodified rare earth chlorides, and the remaining steps were carried out according to Example 1. The obtained rare earth modified nanomaterials were named CK-La@DL, CK-Ce@DL, and CK-Y@DL, respectively.

[0060] Comparative Example 2

[0061] The mass ratio of the modified rare earth chloride (La-Na) to calcium oxide in the preparation process of the rare earth modified nanomaterial in Example 1 was set to 10:1, and the remaining steps were carried out according to Example 1. The prepared modified rare earth complex was named La@DL-1.

[0062] Comparative Example 3

[0063] In the preparation process of the rare earth modified nanomaterial in Example 1, the mass ratio of the modified rare earth chloride (La-DL) to calcium oxide was 1:2, and the remaining steps were carried out according to Example 1. The prepared modified rare earth complex was named La@DL-2.

[0064] Comparative Example 4

[0065] The mass of lanthanum chloride in the preparation process of the modified rare earth chloride in Example 1 was changed to 600 g, and the remaining steps were carried out according to Example 1. The prepared modified rare earth complex was named La@DL-3.

[0066] Comparative Example 5

[0067] The mass of lanthanum chloride hexahydrate in the preparation process of the modified rare earth chloride in Example 1 was 50 g, and the remaining steps were carried out according to Example 1. The prepared modified rare earth complex was named La@DL-4.

[0068] Comparative Example 6

[0069] The modified rare earth chloride (La-Na) and calcium oxide in Example 1 were replaced by an equal amount of sodium benzoate, and the remaining steps were carried out according to Example 1. The obtained modified rare earth complex was named La@DL-5.

[0070] Comparative Example 7

[0071] The modified rare earth chloride (La-Na) in Example 1 was replaced by calcium oxide, and the remaining steps were carried out according to Example 1. The obtained modified rare earth complex was named La@DL-6.

[0072] Comparative Example 8

[0073] The modified rare earth chloride (La-Na) and calcium oxide in Example 1 were replaced by an equal amount of lanthanum chloride, and the remaining steps were carried out according to Example 1. The obtained modified rare earth complex was named La@DL-7.

[0074] Comparative Example 9

[0075] The modified rare earth chloride (La-Na) and calcium oxide in Example 1 were replaced by an equal amount of cerium chloride, and the remaining steps were carried out according to Example 1. The obtained modified rare earth complex was named Ce@DL-7.

[0076] Comparative Example 10

[0077] The modified rare earth chloride (La-Na) and calcium oxide in Example 1 were replaced by an equal amount of cerium chloride, and the remaining steps were carried out according to Example 1. The obtained modified rare earth complex was named Y@DL-7.

[0078] Application Examples

[0079] The rare earth modified nanomaterials obtained in Examples 1 to 3 were tableted using a tablet press to obtain solid materials with a diameter of about 5 mm and a thickness of about 3 mm.

[0080] Comparative Application Examples

[0081] The rare earth modified nanomaterials prepared in Comparative Examples 1 to 10 were tableted using a tablet press as control samples to obtain solid materials with a diameter of about 5 mm and a thickness of about 3 mm.

[0082] Experimental Example 1 Detection of the antibacterial properties of tablets made of different materials against Verticillium dahliae

[0083] The 15 different rare earth modified nanomaterials prepared in the application examples and comparative application examples were pressed into tablets for anti-Verticillium dahliae test using the following method: a 5 mm punch was used to punch out a bacterial cake of Verticillium dahliae that grew normally in a PDA culture medium, which was then inverted into the PDA culture medium using an inoculation shovel and cultured in a 30°C biochemical incubator for 48 h. The pressed tablets were then evenly covered 2 cm away from the center of the bacterial cake, and the tablets were placed in the incubator again for culture for 120 h before being taken out and the diameter of the inhibition zone of each experimental group was measured.

[0084] The results are as follows Figure 1 As shown, the first column from left to right are the blank control group (sterilized silica is used as the tableting material), La@DL, Ce@DL, and Y@DL; the second column from left to right are CK-La@DL, CK-Ce@DL, CK-Y@DL, and La@DL-1; the third column from left to right are La@DL-2, La@DL-3, La@DL-4, and La@DL-5; and the fourth column from left to right are La@DL-6, La@DL-7, Ce@DL-7, and Y@DL-7.

[0085] Diagram of the antibacterial effect on Verticillium dahliae. The inhibition rate was calculated as follows: colony growth diameter of the control group - colony growth diameter of the experimental group / colony growth diameter of the control group. The inhibition rates of La@DL, Ce@DL, and Y@DL against Verticillium dahliae were 99.99%, 87.69%, and 86.51%, respectively; the inhibition rates of CK-La@DL, CK-Ce@DL, and CK-Y@DL against Verticillium dahliae were 61.80%, 21.64%, and 19.32%, respectively; the inhibition rates of La@DL-1, La@DL-2, La@DL-3, La@DL-4, La@DL-5, and La@DL-6 were 17.32%, 15.61%, 17.42%, 14.16%, 16.50%, and 18.06%, respectively; and the inhibition rates of La@DL-7, Ce@DL-7, and Y@DL-7 were 12.50%, 14.31%, and 13.50%, respectively. The antibacterial effects of the materials prepared in the examples above were significantly higher than those of the comparative examples, and La@DL had the best performance in inhibiting Verticillium dahliae and was significantly higher than that of the other materials.

[0086] Experimental Example 2 Detection of the antibacterial properties of different materials against Verticillium dahliae

[0087] According to the antibacterial test results of Experimental Example 1, materials with an antibacterial rate of more than 60% were screened for field planting experiments on cotton. The experimental location was the Aksu cotton region in Xinjiang. The time was June, July, and August when cotton Verticillium wilt was prone to outbreak. The materials La@DL, Ce@DL, Y@DL, and CK-La@DL were diluted 500 times and then used to irrigate the roots of infected cotton. Three parallel groups were set up for each experiment. The experimental period was 45 days, and the root irrigation dosage was 1500kg / 667m 2 (mu), set the cotton plants without root irrigation as the blank group, and design the irrigation rate according to 1500kg / 667m 2 The control group was irrigated with tap water at an addition rate of 1000 mu (approximately 1000 mu). After the test period, the cotton in the test field was observed for appearance, boll opening, and average cotton yield. Data were collected to calculate the cure rates of different materials for cotton Verticillium wilt. The experimental results are shown in Table 1.

[0088] Table 1 Cure rate of cotton Verticillium wilt by different materials

[0089] Group Cure rate (%) Blank group 3 control group 22 La@DL 77 Ce@DL 64 Y@DL 68 CK-La@DL 53

[0090] Among them, the cure rates of La@DL, Ce@DL, Y@DL, CK-La@DL, control group and blank group were 77%, 64%, 68%, 53%, 22% and 3% respectively. The above material RE@DL had the best cure effect on cotton Verticillium wilt, with the highest cure rate, which was significantly higher than that of the blank control and the materials obtained from rare earth chlorides without modification.

[0091] Experimental Example 3: Detection of pH value of cotton root soil after treatment with different materials

[0092] The experimental sample is the cotton root soil planted in the field in Experimental Example 2. The treatment group is the same as Experimental Example 2, with a total of 6 groups: blank group, control group, La@DL, Ce@DL, Y@DL, CK-La@DL. The cotton roots after the cure rate was detected in Experimental Example 2 were collected in a ziplock bag, and visible gravel and insects visible to the naked eye were manually removed. By shaking the soil, the soil 2-5mm close to the cotton root was collected, and about 20g was collected per plant. The collected soil was placed in a cool and ventilated place to dry naturally (avoid direct sunlight), ground and passed through a 2mm nylon sieve, and stored in a drying container for standby use. 10g of soil was weighed, 25mL of deionized water was added to a centrifuge tube, and the centrifuge tube was then placed in a horizontal oscillator to vibrate at 200r / min for 30min. After standing for 30min, centrifugation was performed, and the centrifugal conditions were: 4000r / min, 10min, and the supernatant was taken. The cotton root soil of each treatment group was set up with 3 replicates and 3 parallel groups. A calibrated pH meter was inserted into the soil supernatant of different treatment groups and the reading was taken after stabilization. Deionized water was used for calibration once in each parallel / repeated measurement. The experimental results are shown in Table 2.

[0093] Group pH Blank group 5.4 control group 5.7 La@DL 6.8 Ce@DL 6.4 Y@DL 6.4 CK-La@DL 6.0

[0094] The pH values ​​of the La@DL, Ce@DL, Y@DL, CK-La@DL, control, and blank groups were 6.8, 6.4, 6.4, 6.0, 5.7, and 5.4, respectively. The La@DL material significantly improved the pH of the cotton root soil, significantly outperforming the blank control and unmodified rare earth chloride materials (the optimal soil pH for cotton plants is 6.0-7.5).

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rare earth modified nanomaterial RE@DL, characterized by: The rare earth modified nanomaterial RE@DL is prepared from modified rare earth chloride RE-Na and calcium oxide. The modified rare earth chloride RE-Na is prepared by modifying rare earth chloride with sodium benzoate.

2. The rare earth modified nanomaterial RE@DL according to claim 1, characterized in that: The rare earth chloride is a mixture of one or more of lanthanum chloride, cerium chloride and yttrium chloride.

3. The rare earth modified nanomaterial RE@DL according to claim 1, characterized in that: The mass ratio of the sodium benzoate to the rare earth chloride is (1-3): (3-5).

4. The rare earth modified nanomaterial RE@DL according to claim 1, characterized in that: The preparation method of the modified rare earth chloride RE-Na is: After adding rare earth chloride into sodium benzoate aqueous solution, stirring and mixing at a temperature of 55-65° C., a hydrothermal reaction is carried out, and the reaction product is dried and ground to obtain modified rare earth chloride RE-Na.

5. The rare earth modified nanomaterial RE@DL according to claim 1, characterized in that: The mass concentration of the sodium benzoate solution is 30-100 g / L.

6. The rare earth modified nanomaterial RE@DL according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 120-150°C, and the reaction time is 6-8 hours; Preferably, the drying temperature is 80° C.-100° C., and the drying time is 36-48 hours.

7. The method for preparing the rare earth modified nanomaterial RE@DL according to any one of claims 1 to 6, characterized in that: The steps include: After deionized water reacts with calcium oxide, modified rare earth chloride RE-Na is added thereto. After being fully stirred, the reaction solution is transferred to an oven and dried to a powder state, and then transferred to a muffle furnace for calcination. The calcined powder is wet-grinded and vacuum-dried to obtain rare earth modified nanomaterial RE@DL.

8. The method for preparing the rare earth modified nanomaterial RE@DL according to claim 7, characterized in that: The amount of calcium oxide added is 23-53 g / L per liter of deionized water; Preferably, the mass concentration of the modified rare earth chloride in the mixed system of calcium hydroxide and deionized water is 110-150 g / L. Preferably, the drying conditions are: drying at 80-100°C for 36-48h; Preferably, the calcination conditions are: calcination at 500-700°C for 4h-6h; Preferably, the wet sand grinding condition is sand grinding in a sand grinder at 3500-4000 r / min for 4.0-6.0 h; Preferably, the average particle size of the rare earth modified nanomaterial RE@DL is 70-100 nm.

9. Use of the rare earth modified nanomaterial RE@DL according to any one of claims 1 to 6 in the preparation of a biocontrol agent for inhibiting Verticillium dahliae.

10. Use of the rare earth modified nanomaterial RE@DL according to any one of claims 1 to 6 in the preparation of a biological control agent for cotton Verticillium wilt.

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