Polyaspartic acid rare earth chelate and application thereof

Abstract

The invention belongs to the technical field of agriculture, and particularly relates to a polyaspartic acid rare earth chelate and application thereof. The polyaspartic acid-rare earth chelate is formed by chelating polyaspartic acid and rare earth elements, and when the polyaspartic acid-rare earth chelate is used for agricultural planting, the polyaspartic acid-rare earth chelate can show a remarkable synergistic effect in the aspects of promoting plant growth, improving crop yield, improving crop quality and inducing plant disease resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of agriculture, and more specifically relates to a polyaspartic acid rare earth chelate and application thereof. Background Art

[0002] In modern agriculture, the scientific application of fertilizers is of great significance for increasing crop yields, improving soil quality and promoting sustainable agricultural development. However, traditional fertilizers often face problems such as low nutrient utilization, serious loss and environmental pollution during application. In order to improve fertilizer utilization efficiency, researchers are constantly exploring the preparation of fertilizer enhancers, in order to reduce fertilizer usage while increasing crop nutrient absorption.

[0003] Due to their unique physical and chemical properties, a large number of studies have shown that rare earth metal elements have shown significant effects in promoting plant growth and enhancing stress resistance. However, the use of rare earth elements alone as synergists still faces some challenges and limitations. For example, the frequent use of rare earth elements alone can easily lead to the rare earth elements being lost by rainwater and being solidified by anions in the soil and losing their activity. The use of rare earth salts alone may lead to low plant absorption efficiency due to selective absorption and competitive inhibition.

[0004] Therefore, how to overcome the problems existing in the prior art of using rare earth elements as fertilizer enhancers has become a difficult problem that technicians in this field need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a polyaspartic acid rare earth chelate and its application to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a polyaspartic acid rare earth chelate, wherein the polyaspartic acid rare earth chelate is formed by chelating polyaspartic acid with a rare earth element;

[0008] The molar ratio of the polyaspartic acid to the rare earth element is 1:0.1-10.

[0009] Furthermore, the rare earth element includes at least one of lanthanide elements, scandium and yttrium.

[0010] The lanthanide element is at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium.

[0011] Optionally, the rare earth element includes at least one of lanthanum, cerium, praseodymium, neodymium, samarium, dysprosium, holmium, erbium, thulium and yttrium.

[0012] Furthermore, the molar ratio of the polyaspartic acid to the rare earth element is 1:0.1-0.3.

[0013] Optionally, the molar ratio of the polyaspartic acid to the rare earth element is 1:0.15-0.25.

[0014] The second technical solution of the present invention is to provide a method for preparing the above-mentioned polyaspartic acid rare earth chelate, comprising the following steps:

[0015] dissolving polysuccinimide in aqueous ammonia and adjusting the pH to 4 to obtain a polysuccinimide solution;

[0016] dissolving a rare earth salt in water to obtain a rare earth salt solution;

[0017] The polysuccinimide solution and the rare earth salt solution are mixed, heated and stirred for reaction, and then crystallized, filtered and dried to obtain the polyaspartic acid rare earth chelate.

[0018] Furthermore, the mass volume ratio of the polysuccinimide and ammonia water is 2g:15mL.

[0019] Furthermore, the concentration of the ammonia water is 1M.

[0020] Furthermore, the pH is adjusted using hydrochloric acid.

[0021] Furthermore, the usage ratio of the rare earth salt and water is 4.9g:15mL.

[0022] Furthermore, the rare earth salt is a water-soluble salt of a rare earth element or a hydrate of a water-soluble salt, such as a nitrate or a nitrate hydrate.

[0023] Furthermore, the temperature of the heating and stirring reaction is 60° C. and the time is 6 hours.

[0024] The third technical solution of the present invention is to provide a method for preparing the above-mentioned polyaspartic acid rare earth chelate, the steps comprising:

[0025] dissolving polyaspartic acid in water to prepare a polyaspartic acid aqueous solution;

[0026] Dissolving a rare earth salt in water to prepare a rare earth salt solution;

[0027] The rare earth salt aqueous solution and the polyaspartic acid aqueous solution are mixed and stirred for reaction, and then crystallized, filtered and dried to obtain the polyaspartic acid rare earth chelate.

[0028] Furthermore, the dosage ratio of the polyaspartic acid and water is 1.15 g:20 mL.

[0029] Furthermore, the rare earth salt is a water-soluble salt of a rare earth element or a hydrate of a water-soluble salt, such as a nitrate or a nitrate hydrate.

[0030] Furthermore, the dosage ratio of the rare earth salt to water is 0.87 g:10 mL.

[0031] Furthermore, the mixing and stirring reaction time is 4 hours.

[0032] The fourth technical solution of the present invention is to provide an application of the above-mentioned polyaspartic acid rare earth chelate as a synergist in promoting plant growth, increasing crop yield, improving crop quality or improving plant disease resistance.

[0033] The application dosage of polyaspartic acid rare earth chelate is adjusted according to the plant species, growth stage and soil conditions to achieve the best effect of promoting growth and improving quality.

[0034] The polyaspartic acid rare earth chelate is applied by foliar spraying, soil irrigation or root fertilization or a combination thereof.

[0035] The present invention discloses the following technical effects:

[0036] Compared with using polyaspartic acid of the same concentration or the same amount of rare earth elements alone, the polyaspartic acid rare earth chelate provided by the invention exhibits significant synergistic effects in promoting plant growth, increasing crop yield, improving crop quality and inducing plant disease resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 XPS spectra of cerium, lanthanum and polyaspartic acid chelated; a is polyaspartic acid + cerium, and the inset is a local magnified image; b is polyaspartic acid + lanthanum, and the inset is a local magnified image.

[0039] Figure 2 The XPS spectra of praseodymium, neodymium and polyaspartic acid chelate; a is polyaspartic acid + praseodymium, and the inset is a local magnified image; b is polyaspartic acid + neodymium, and the inset is a local magnified image.

[0040] Figure 3 The XPS spectra of dysprosium, holmium and polyaspartic acid chelate; a is polyaspartic acid + dysprosium, and the inset is a local magnified image; b is polyaspartic acid + holmium, and the inset is a local magnified image.

[0041] Figure 4The XPS spectra of erbium, thulium and polyaspartic acid chelate; a is polyaspartic acid + erbium, and the inset is a local magnified image; b is polyaspartic acid + thulium, and the inset is a local magnified image.

[0042] Figure 5 The XPS spectra of gadolinium, yttrium and polyaspartic acid chelate; a is polyaspartic acid + gadolinium, and the inset is a local magnified image; b is polyaspartic acid + yttrium, and the inset is a local magnified image.

[0043] Figure 6 This is the XPS spectrum of samarium chelated with polyaspartic acid, where the inset is a local magnified view.

[0044] Figure 7 This is the infrared spectrum of polyaspartic acid and cerium, lanthanum and praseodymium chelates.

[0045] Figure 8 This is the infrared spectrum of polyaspartic acid and dysprosium, holmium and erbium chelate.

[0046] Fig. 9 This is the infrared spectrum of polyaspartic acid and praseodymium, neodymium and gadolinium chelate.

[0047] Fig.10 This is the infrared spectrum of polyaspartic acid and thulium, yttrium, and samarium chelates. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0049] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0050] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0051] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0052] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0053] The reaction equation of polyaspartic acid chelating with rare earth ions is shown in Formula 1 below:

[0054]

[0055] Wherein, M is the ionic state of the rare earth element, n≥1, n1≥1, n2≥0, n3≥0.

[0056] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products, and the so-called "normal temperature" and "room temperature" both refer to 20-30°C.

[0057] Example 1

[0058] The preparation method of polyaspartic acid rare earth chelate comprises the following steps:

[0059] S1, weigh 2.0 g of polysuccinimide and dissolve it in 15 mL of 1 M ammonia water, and adjust the pH value to 4 with 10 M hydrochloric acid solution to obtain a polysuccinimide solution;

[0060] S2, dissolving 4.9 g of dysprosium nitrate hexahydrate in 15 mL of distilled water to obtain an aqueous solution of cerium nitrate hexahydrate;

[0061] S3. Mix the polysuccinimide solution and the dysprosium nitrate hexahydrate aqueous solution, stir magnetically for 6 hours at a constant temperature of 60°C, cool to room temperature, add 50 mL of ethanol, precipitate a white solid, filter, dissolve the solid product with 30 mL of distilled water, add 50 mL of ethanol, precipitate a white solid, filter, and dry to obtain a white powder, which is polyaspartic acid rare earth chelate (0.87 g).

[0062] Example 2

[0063] The preparation method of polyaspartic acid rare earth chelate comprises the following steps:

[0064] S1. Weigh 1.15 g of polyaspartic acid and dissolve it in 20 mL of water to prepare a polyaspartic acid aqueous solution;

[0065] S2. Weigh 0.86 g of dysprosium nitrate hexahydrate and dissolve it in 10 mL of water to prepare a rare earth salt solution;

[0066] S3. Slowly add the rare earth salt solution dropwise to the polyaspartic acid aqueous solution under stirring at room temperature, stir at room temperature for 4 hours, then add 50 mL of ethanol to precipitate a white solid, filter it, add 20 mL of distilled water to the solid product to dissolve it, then add 50 mL of ethanol, after a white solid precipitates, filter and dry it, and the obtained white powder is polyaspartic acid rare earth chelate (0.61 g).

[0067] Example 3 (10%)

[0068] Compared with Example 2, the only difference is that the amount of dysprosium nitrate hexahydrate is adjusted to 0.43 g.

[0069] Example 4 (30%)

[0070] Compared with Example 2, the only difference is that the amount of dysprosium nitrate hexahydrate is adjusted to 1.29 g.

[0071] Example 5 (40%)

[0072] Compared with Example 2, the only difference is that the amount of dysprosium nitrate hexahydrate is adjusted to 1.72 g.

[0073] Example 6 (50%)

[0074] Compared with Example 2, the only difference is that the amount of dysprosium nitrate hexahydrate is adjusted to 2.15 g.

[0075] Test Example 1: Detection of rare earth element content

[0076] The rare earth element content of the polyaspartic acid rare earth chelates prepared in Examples 1 to 6 was tested. The results are shown in Table 1.

[0077] Detection method: Take 0.1g of polyaspartic acid rare earth chelate, dissolve it with 5mL of nitric acid, 3mL of hydrofluoric acid and 2mL of hydrochloric acid, pour it into a microwave digestion tank, and perform microwave digestion according to the microwave digestion program: the first stage is set to 120℃ and the pressure is 1.52×10 6 Pa, power 1000W digestion 4min; the second stage set temperature 150℃, pressure 1.82×10 6 Pa, power 1000W digestion 4min; the third stage set temperature 180℃, pressure 2.43×10 6 Pa, power 1000W for 4 minutes. After digestion, set the temperature of the electric heating plate to 260℃ to drive out the acid until it is almost dry. If the solution is still yellow, add a little distilled water and repeat until the solution is colorless and transparent. Then transfer the digested sample to a PET bottle, dilute to the scale with ultrapure water, filter with a 0.45μm microporous filter membrane, and store at low temperature (refrigerated at 5℃) waiting for testing.

[0078] ICP-MS was used to determine the element content. The instrument working conditions were: RF power 1550 W, plasma gas flow rate 15 L min -1 , carrier gas flow rate 1.0L·min -1 , atomization chamber temperature 2 °C, sampling depth 7.0 mm, analysis time 0.1 s, repeated 3 times.

[0079] Table 1

[0080]

[0081] It can be seen from the data in Table 1 that the polyaspartic acid rare earth chelate with corresponding rare earth content was successfully prepared by the method of the present invention.

[0082] In order to further verify the polyaspartic acid rare earth chelate, polyaspartic acid rare earth chelates with different rare earth types were designed with a planned rare earth element content of 20wt.%, and the rare earth content therein was detected. The results are shown in Table 2.

[0083] Table 2

[0084] Polyaspartic acid rare earth chelate Rare earth element content / wt.% samarium 19.3 holmium 21.5 erbium 20.7 cerium 18.5 yttrium 17.1 lanthanum 18.6 praseodymium 16.2 neodymium 19.2 thulium 21.8 gadolinium 18.9

[0085] The polyaspartic acid rare earth chelate in Example 2 and 10 in Table 2 was characterized by XPS. The results are as follows: Figure 1 to Figure 6 shown.

[0086] Figure 1 XPS spectra of cerium, lanthanum and polyaspartic acid chelated; a is polyaspartic acid + cerium, and the inset is a local magnified image; b is polyaspartic acid + lanthanum, and the inset is a local magnified image.

[0087] Figure 2 The XPS spectra of praseodymium, neodymium and polyaspartic acid chelate; a is polyaspartic acid + praseodymium, and the inset is a local magnified image; b is polyaspartic acid + neodymium, and the inset is a local magnified image.

[0088] Figure 3 The XPS spectra of dysprosium, holmium and polyaspartic acid chelate; a is polyaspartic acid + dysprosium, and the inset is a local magnified image; b is polyaspartic acid + holmium, and the inset is a local magnified image.

[0089] Figure 4 The XPS spectra of erbium, thulium and polyaspartic acid chelate; a is polyaspartic acid + erbium, and the inset is a local magnified image; b is polyaspartic acid + thulium, and the inset is a local magnified image.

[0090] Figure 5The XPS spectra of gadolinium, yttrium and polyaspartic acid chelate; a is polyaspartic acid + gadolinium, and the inset is a local magnified image; b is polyaspartic acid + yttrium, and the inset is a local magnified image.

[0091] Figure 6 This is the XPS spectrum of samarium chelated with polyaspartic acid, where the inset is a local magnified view.

[0092] Depend on Figure 1 to Figure 6 The overall spectrum and illustration of the chelate in the figure show that in rare earth chelates, different rare earth elements can be chelated with polyaspartic acid to obtain different types of rare earth chelates. In the XPS spectra of different chelates, it can be clearly seen that different types of rare earth chelates have specific peaks on specific orbits. For example, in the illustration Ce3d (882eV), La3d (835eV), Pr3d (932eV), Nd3d (980eV), Dy3d (1295eV), Ho4d (163eV), Er4d (167eV), Tm4d (179eV), Gd4d (142eV), Y3d (157eV) and Sm3d (1083eV) spectra, specific peaks are observed. These binding energies are respectively attributed to the functional groups formed by the combination of different rare earth elements and specific groups on aspartic acid. In addition, peaks of different rare earth elements also appeared in the overall spectrum before and after chelation, further confirming the successful chelation of rare earth elements with polyaspartic acid. The rare earth elements were effectively chelated on polyaspartic acid. The XPS results showed that different rare earth chelates were successfully prepared.

[0093] The infrared spectra of the above 11 chelates were measured by IR. The results are as follows: Figure 7 to Figure 10 shown.

[0094] Figure 7 This is the infrared spectrum of polyaspartic acid and cerium, lanthanum and praseodymium chelates.

[0095] Figure 8 This is the infrared spectrum of polyaspartic acid and dysprosium, holmium and erbium chelate.

[0096] Fig. 9 This is the infrared spectrum of polyaspartic acid and praseodymium, neodymium and gadolinium chelate.

[0097] Fig.10 This is the infrared spectrum of polyaspartic acid and thulium, yttrium, and samarium chelates.

[0098] Depend on Figure 7 to Figure 10 As shown in the figure, after polyaspartic acid chelates rare earth elements, compared with the infrared spectrum of polyaspartic acid, the -1A significant vibration peak appears at the chelation point, indicating that after polyaspartic acid is chelated with rare earth elements, a significant change occurs in infrared detection, and a new vibration peak appears, which indirectly proves that the preparation of rare earth chelate is successful.

[0099] Test Example 2 Seed germination experiment

[0100] Wheat seeds (Zhengmai 379) were soaked in a 1% sodium hypochlorite aqueous solution for 5 hours to prevent them from becoming moldy during germination. After washing three times with clean water, the wheat seeds were placed in a culture dish and incubated with an aqueous solution of polyaspartic acid rare earth chelate with different rare earth element contents in Examples 2 to 6 (the rare earth element concentration was 10 -5 mol / L) was used as the experimental group, and the concentration was 10 -5 mol / L of the corresponding rare earth salt solution, the polyaspartic acid solution of the same concentration as the chelate experimental group, and the mixed group with the same content of rare earth salt + polyaspartic acid in the chelate as the control group, and the blank control group was immersed in an equal volume of water. The immersion condition parameters were: constant temperature 25℃, 12h.

[0101] After the soaked seeds were taken out, they were placed on filter paper to absorb excess water, and then evenly sown into agar culture medium cups. Ten seeds were treated in each experiment, and three parallel tests were conducted. The agar culture medium cups were then placed in a constant temperature box, and the temperature was maintained at about 25°C and the humidity was above 95%. After 36 hours, the germination of the seeds was checked and the number of germinated seeds was recorded. The results are shown in Table 3.

[0102] Table 3

[0103]

[0104] It can be seen from the data in Table 3 that polyaspartic acid rare earth chelate can significantly improve the germination rate compared with the use of its rare earth salt and polyaspartic acid alone, as well as a simple mixed solution of rare earth salt and polyaspartic acid. Among them, the polyaspartic acid rare earth chelate with a rare earth content of 20% prepared in Example 2 has a more significant effect on promoting seed germination than rare earth chelates with other contents.

[0105] The chelate prepared in Experimental Example 1 with a planned rare earth element content of 20 wt.% was used in the above seed germination experiment. The results are shown in Table 4.

[0106] Table 4

[0107]

[0108]

[0109] The data in Table 4 further show that the use of polyaspartic acid rare earth chelate can significantly improve the germination rate compared with the use of rare earth salts and polyaspartic acid alone, as well as a simple mixed solution of rare earth salts and polyaspartic acid.

[0110] Test Example 3: Mulberry plot test

[0111] The planting density is about 600 plants / mu, and the test area is 980m 2 , divided into 7 areas, each area is 140m 2 . Each plot has 14 treatments: a blank control group with base fertilizer; a polyaspartic acid control group with base fertilizer + polyaspartic acid; a rare earth salt control group with base fertilizer + rare earth salts (cerium, lanthanum, dysprosium, samarium), a total of four groups; a control group with base fertilizer + rare earth salt + polyaspartic acid, a total of four groups; a test group with base fertilizer + rare earth chelate (cerium, lanthanum, dysprosium, samarium), a total of four groups. The application of base fertilizer in the field is consistent, and the base fertilizer is 25% compound fertilizer (N:P2O5:K2O=9:8:8) 700kg / hm 2 . In July, polyaspartic acid, rare earth salts and rare earth chelates (350g plus 36kg of water) were sprayed on mulberry leaves. 30 days after spraying, the strip length and mulberry leaf diameter were investigated, and the mulberry leaf yield was investigated in September. Among them, the dosage of the rare earth salt control group was kept consistent with the dosage of rare earth elements in the rare earth chelate test group; polyaspartic acid was used 280g per mu; the simple mixed solution of rare earth salt + polyaspartic acid was treated with the dosage of rare earth elements in the rare earth chelate test group + polyaspartic acid, which was 280g per mu. The polyaspartic acid rare earth chelate used was prepared according to the planned content of 20%, and the actual content was: cerium (18.5%), lanthanum (18.6%), dysprosium (18.7%), and samarium (19.3%). The effect after application is shown in Table 5.

[0112] Table 5

[0113]

[0114]

[0115] From the data in Table 5, it can be seen that the use of polyaspartic acid rare earth chelate can increase the area of ​​mulberry leaves, the length of mulberry branches and the yield of mulberry trees compared with the use of rare earth salts or polyaspartic acid alone, as well as the simple mixed solution of rare earth salts and polyaspartic acid, indicating that it has a synergistic effect after being prepared as a chelate. Compared with the base fertilizer control, all indicators have been significantly improved.

[0116] Test Example 4 Sugarcane Planting Test

[0117] The experiment adopted a randomized block arrangement, with 14 treatments, three plots in each treatment, and an area of ​​70m in each plot. 2 , with protection rows all around.

[0118] The sowing density is 120,000 buds / hm2 2 The sowing time is March and the yield measurement time is November.

[0119] The 14 treatments were: a control group with base fertilizer, a polyaspartic acid control group with base fertilizer + polyaspartic acid, a rare earth salt control group with base fertilizer + rare earth salt (4 groups), an experimental group with base fertilizer + rare earth chelate (4 groups), and a mixed control group with base fertilizer + polyaspartic acid + rare earth salt (4 groups).

[0120] The base fertilizer application in the field is consistent, and the base fertilizer is 25% compound fertilizer (N:P2O5:K2O=9:8:8) 850kg / hm 2 In May, the application amount of rare earth chelate was 350g of rare earth chelate per mu and 30kg of water, sprayed on sugarcane; the application amount of rare earth salt was kept consistent with the amount of rare earth elements in the rare earth chelate; polyaspartic acid was 280g per mu; the simple mixed solution of rare earth salt + polyaspartic acid was treated with the amount of rare earth elements in the rare earth chelate test group + polyaspartic acid, which was 280g per mu. The polyaspartic acid rare earth chelate used was prepared according to the planned content of 20%, and the actual content was: cerium (18.5%), lanthanum (18.6%), dysprosium (18.7%), samarium (19.3%). The effect after application is shown in Table 6.

[0121] Table 6

[0122]

[0123] As shown in Table 6, the use of polyaspartic acid rare earth chelate can increase the sugar content and yield of sugarcane, compared with the use of rare earth salt or polyaspartic acid alone, and the simple mixed solution of rare earth salt and polyaspartic acid, and has a synergistic effect. Compared with the base fertilizer control, all indicators have been significantly improved.

[0124] Test Example 5: Rice room temperature induced disease resistance test

[0125] At 25°C, rice seedlings with 3 to 4 true leaves and uniform growth were selected, and the sample solution was evenly sprayed on the rice seedlings 14 days, 7 days, 3 days and 1 day before inoculation with rice blast pathogens. The blank control was sprayed with water, the polyaspartic acid aqueous solution was sprayed with polyaspartic acid control group, the rare earth salt solution was sprayed with rare earth salt solution, the mixed control group was sprayed with rare earth salt solution + polyaspartic acid aqueous solution, and the polyaspartic acid rare earth chelate aqueous solution was sprayed with polyaspartic acid rare earth chelate aqueous solution as the experimental group. Artificial inoculation was performed 24 hours after the last medication. The concentration of the rare earth salt solution was 500 mg / L, the concentration of the polyaspartic acid aqueous solution was the concentration of polyaspartic acid when the rare earth element in the chelate was 500 mg / L, which was about 4000 mg / L, and the concentration of the rare earth element in the polyaspartic acid rare earth chelate aqueous solution was 500 mg / L.

[0126] When inoculating, add pure water to the culture dish full of spores, gently scrape the surface spores with a stainless steel spoon, filter through double-layer gauze, and count the spore suspension prepared by hemocytometer counting. The concentration of rice blast fungus spores is controlled to be 3-5×10 5 Then use a gas compressor to connect the nozzle of the throat sprayer through a pressure-resistant tube, spray the rice seedlings evenly, and immediately move them to a constant temperature and humidity chamber (temperature: 26-28°C; relative humidity: 100%) to induce for 24 hours. After 6 days of blank control, the lesions are stable, and then the grading survey can be carried out according to the number of lesions. The grading standards are as follows: 0, no disease; 1, less than 5 leaf lesions; 3, 6-15 leaf lesions; 5, 16-30 leaf lesions; 7, leaf lesions account for about 50% of the leaf area; 9, the lesions are all over the leaves and the leaves are curled and withered.

[0127] The disease index or number of lesions in each treatment was compared with the blank control, and the control effect was calculated. The results are shown in Table 7.

[0128] The polyaspartic acid rare earth chelate used is prepared according to the planned content of 20%, and the actual content is: cerium (18.5%), lanthanum (18.6%), dysprosium (18.7%), and samarium (19.3%).

[0129] Table 7

[0130]

[0131]

[0132] It can be seen from Table 7 that, under the same treatment concentration, the rare earth complex of polyaspartic acid is better than the use of rare earth salt and polyaspartic acid alone, and better than the ordinary mixed solution of rare earth salt and polyaspartic acid. The relevant treatments are significantly higher than the clear water control group.

[0133] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0134] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polyaspartic acid rare earth chelate, characterized in that: The polyaspartic acid rare earth chelate is formed by chelating polyaspartic acid with a rare earth element; The molar ratio of the polyaspartic acid to the rare earth element is 1:0.1-10.

2. The polyaspartic acid rare earth chelate according to claim 1, characterized in that: The rare earth element comprises at least one of lanthanide elements, scandium and yttrium; and / or, The molar ratio of the polyaspartic acid to the rare earth element is 1:0.1-0.

3.

3. The polyaspartic acid rare earth chelate according to claim 2, characterized in that: The rare earth element comprises at least one of lanthanum, cerium, praseodymium, neodymium, samarium, dysprosium, holmium, erbium, thulium and yttrium; and / or, The molar ratio of the polyaspartic acid to the rare earth element is 1:0.15-0.

25.

4. A method for preparing the polyaspartic acid rare earth chelate according to any one of claims 1 to 3, characterized in that the steps include: dissolving polysuccinimide in aqueous ammonia and adjusting the pH to 4 to obtain a polysuccinimide solution; Dissolving a rare earth salt in water to obtain a rare earth salt solution; The polysuccinimide solution and the rare earth salt solution are mixed, heated and stirred for reaction, and then crystallized, filtered and dried to obtain the polyaspartic acid rare earth chelate.

5. The preparation method according to claim 4, characterized in that: The mass volume ratio of the polysuccinimide and ammonia water is 2g:15mL; and / or, The concentration of the aqueous ammonia is 1M; and / or, The pH is adjusted by using hydrochloric acid; and / or, The ratio of the rare earth salt to water is 4.9 g:15 mL; and / or, The rare earth salt is a water-soluble salt of a rare earth element or a hydrate of a water-soluble salt; and / or, The temperature of the heating and stirring reaction is 60° C. and the time is 6 hours.

6. A method for preparing the polyaspartic acid rare earth chelate according to any one of claims 1 to 3, characterized in that the steps include: dissolving polyaspartic acid in water to prepare a polyaspartic acid aqueous solution; Dissolving a rare earth salt in water to prepare a rare earth salt solution; The rare earth salt aqueous solution and the polyaspartic acid aqueous solution are mixed and stirred for reaction, and then crystallized, filtered and dried to obtain the polyaspartic acid rare earth chelate.

7. The preparation method according to claim 6, characterized in that: The ratio of polyaspartic acid to water is 1.15 g:20 mL; and / or, The rare earth salt is a water-soluble salt of a rare earth element or a hydrate of a water-soluble salt; and / or, The ratio of the rare earth salt to water is 0.87 g:10 mL; and / or, The mixing and stirring reaction time is 4 hours.

8. Use of the polyaspartic acid rare earth chelate according to any one of claims 1 to 3 as a synergist in promoting plant growth, increasing crop yield, improving crop quality or improving plant disease resistance.

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