Chelation-rare earth compound liquid fertilizer and preparation method thereof

Abstract

The invention discloses a chelate-rare earth compound liquid fertilizer and a preparation method thereof, and the chelate-rare earth compound liquid fertilizer comprises the following components in parts by weight: 500-600 parts of pyroligneous liquor, 40-50 parts of monopotassium phosphate, 60-80 parts of dipotassium phosphate, 200-250 parts of chelating agent amine alkyl lignin, 0-50 parts of zinc sulfate, 0-50 parts of ferric sulfate, 0-15 parts of manganese sulfate, 6-12 parts of low-viscosity sodium alginate and 10-25 parts of compound sodium nitrophenolate. 5-15 parts of triacontanol milk powder, 2-8 parts of sodium dodecyl benzene sulfonate, 2-8 parts of carrageenan and 0.5-4 parts of rare earth element chloride. Wherein the chelating agent amine alkyl lignin is obtained by reacting small molecular lignin with caprolactam. According to the chelating-rare earth compound liquid fertilizer, the amino alkyl lignin is adopted to replace a traditional EDTA chelating agent, the chelating capacity with rare metal elements is remarkably improved, meanwhile, the amino alkyl lignin is derived from natural lignin and can be degraded by microorganisms, and the environmental accumulation risk is reduced.

Description

Technical Field

[0001] The present invention relates to the field of fertilizers, and particularly relates to a chelated-rare earth composite liquid fertilizer and a preparation method thereof. Background Art

[0002] Liquid fertilizer is a fertilizer in liquid form, usually dissolved or diluted before use, and can be used for soil irrigation (such as drip irrigation, flushing) or foliar spraying.

[0003] Foliar fertilizer is usually an application form of liquid fertilizer. As the main organ for plants to absorb nutrients outside the roots, leaves can directly absorb nutrients on the leaf surface. Therefore, foliar fertilizer is an important fertilizer with the characteristics of timely supplementing plant nutrients, improving nutrient utilization rate, and being easy to use.

[0004] Foliar fertilizers can be classified into the following types according to their functions: (1) Nutritional foliar fertilizers: containing a large amount of nitrogen, phosphorus, potassium and trace elements, which can provide various nutrients required for crop growth, improve the nutritional status of crops, and promote crop growth and development, such as rare earth micro-fertilizers, potassium dihydrogen phosphate, potassium phosphite, etc. (2) Regulatory foliar fertilizers: containing substances that can adjust plant growth, which can control the growth and development of plants, such as wood vinegar liquid, auxin, hormones, etc. (3) Biological foliar fertilizers: containing microorganisms and metabolites, which can stimulate crop growth, promote plant metabolism, enhance plant stress resistance, and reduce and prevent pests and diseases, such as humic acid, alginic acid, etc. (4) Composite foliar fertilizers: rich in variety and diverse in mixing forms, and composite foliar fertilizers can provide nutrients for plants and regulate plant growth and development at the same time.

[0005] Regarding composite foliar fertilizers, Chinese patent document CN 107673839A (application number 201710985091.2) discloses a polyaspartic acid chelated rare earth foliar fertilizer. First, hydroxyethyl is introduced into polysuccinimide to obtain hydroxyethyl polysuccinimide; secondly, hydroxyethyl polysuccinimide reacts with acryloyl chloride and then hydrolyzes in an aqueous sodium hydroxide solution to obtain modified polyaspartic acid; then agricultural rare earth is calcined at high temperature and becomes ionic and free in the solution under the action of dilute hydrochloric acid; finally, modified polyaspartic acid chelates rare earth ions and is compounded with the macronutrients and micronutrients required by crops to obtain a polyaspartic acid chelated rare earth foliar fertilizer.

[0006] For another example, Chinese Patent Document CN 112142513A (Application No. 202011030591.9) discloses a chelated foliar fertilizer for vegetables. The foliar fertilizer is made from nano-chitosan, polypeptide solution and metal salt solution; the metal salt solution of the nano-chitosan oligosaccharide-chelated zinc foliar fertilizer is 1-3 parts of zinc sulfate solution with a mass fraction of 2.38%; or the metal salt solution of the nano-chitosan oligosaccharide-chelated iron foliar fertilizer is composed of 1-4 parts of ferrous sulfate solution mixed with 0.2-3 parts of ascorbic acid, and the mass fraction of the ferrous sulfate solution is 7.14%. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a new liquid fertilizer formula and its preparation method. This liquid fertilizer can improve the utilization rate of rare earth elements, is easily absorbed by plants, and can effectively supplement the nutrients required during the entire growth period of navel oranges. During the budding period to the new shoot growth period of navel oranges, it can prevent the yellowing of new shoots, promote leaf photosynthesis, and reduce yellow spot disease; during the flowering period to the young fruit period of navel oranges, it can promote the cell division of young fruits and enhance stress resistance; during the fruit swelling period to the maturity period of navel oranges, it can maintain the health of leaves, promote sugar accumulation and fruit coloring.

[0008] The technical solution to achieve the first object of the present invention is a chelated-rare earth composite liquid fertilizer, which includes the following components in parts by weight: 500-600 parts of wood vinegar, 40-50 parts of potassium dihydrogen phosphate, 60-80 parts of dipotassium hydrogen phosphate, 200-250 parts of chelating agent amine alkyl lignin, 0-50 parts of zinc sulfate, 0-50 parts of ferric sulfate, 0-15 parts of manganese sulfate, 6-12 parts of low-viscosity sodium alginate, 10-25 parts of sodium nitrophenolate, 5-15 parts of triacontanol milk powder, 2-8 parts of sodium dodecylbenzenesulfonate, 2-8 parts of carrageenan, 0.5-4 parts of rare earth element chloride; Among them, the structural formula of the chelating agent amine alkyl lignin is as follows: The rare earth element chloride includes at least one of lanthanum chloride, cerium chloride and neodymium chloride.

[0009] Optionally, in the chelated-rare earth composite liquid fertilizer, the sum of the weight parts of zinc sulfate, ferric sulfate and manganese sulfate is 30-60 parts.

[0010] The technical solution to achieve the second object of the present invention is a preparation method of amine alkyl lignin in a chelated-rare earth composite liquid fertilizer, which includes the following steps: ① Dissolve small molecule lignin in an organic solvent, add a protonic acid as a catalyst, and then add 0.5-0.7 times the mass of lignin of caprolactam to obtain a reaction material.

[0011] ② Heat the reaction material to 80-100°C and stir and react at this temperature for 16-24 hours.

[0012] ③ After the reaction is completed, the reaction solution is slowly added dropwise to an aqueous sodium bicarbonate solution, and a large amount of brownish-yellow precipitate is precipitated. After the addition of the reaction solution is complete, suction filtration is carried out, and the solid obtained after suction filtration is washed with distilled water and dried to obtain a brown powder, which is the modified aminoalkyl lignin.

[0013] The molecular weight of the small molecule lignin is 1000 - 2000 Da.

[0014] In the above step ①, the organic solvent is one or a combination of more than one of 1,4-dioxane, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0015] In the above step ①, the protonic acid is one of sulfuric acid, methanesulfonic acid, and trifluoroacetic acid; the addition amount of the protonic acid catalyst is 1% - 3% of the mass of the small molecule lignin.

[0016] In the above step ③, the concentration of the aqueous sodium bicarbonate solution is 0.5 - 2 mol / L.

[0017] The technical solution for achieving the third object of the present invention is a preparation method of a chelating-rare earth composite liquid fertilizer. 500 - 600 parts of wood vinegar, 40 - 50 parts of potassium dihydrogen phosphate, 60 - 80 parts of dipotassium hydrogen phosphate, 200 - 250 parts of chelating agent aminoalkyl lignin, 0 - 50 parts of zinc sulfate, 0 - 50 parts of ferric sulfate, 0 - 15 parts of manganese sulfate, 6 - 12 parts of low-viscosity sodium alginate, 10 - 25 parts of sodium nitrophenolate, 5 - 15 parts of triacontanol milk powder, 2 - 8 parts of sodium dodecylbenzenesulfonate, 2 - 8 parts of carrageenan, and 0.5 - 4 parts of rare earth element chloride are added to a reaction kettle. After the raw materials are mixed evenly in the kettle, chelation is carried out at a rotation speed of 400 ± 50 rad / min and a temperature of 60 ± 10 °C for 3 - 5 h, and then the temperature of the reaction product is reduced to below 30 °C to obtain the liquid fertilizer.

[0018] Optionally, during the preparation, after the raw materials are mixed evenly in the kettle, chelation is carried out at a rotation speed of 400 rad / min and a temperature of 60 °C for 3 - 5 h, and then the temperature of the reaction product is reduced to below 30 °C to obtain the liquid fertilizer.

[0019] The technical solution for achieving the fourth object of the present invention is an aminoalkyl lignin used as a chelating agent in a liquid fertilizer, and the structural formula is as follows: 。

[0020] The present invention has positive effects: (1) The chelating-rare earth composite liquid fertilizer of the present invention includes a chelating agent, amine-alkylated lignin. This chelating agent has multi-dentate coordination units, which can coordinate with rare earth elements, significantly improving the absorption and transportation efficiency of rare earth elements on the leaf surface. Amine-alkylated lignin introduces nitrogen-containing coordination groups onto the lignin skeleton through chemical modification, enabling it to have multiple coordination capabilities of phenolic hydroxyl groups, carboxyl groups, and amino groups, and forming highly stable chelate structures with rare earth and trace elements.

[0021] (2) The chelating-rare earth composite liquid fertilizer of the present invention enhances the leaf surface adhesion after foliar application through the inherent hydrophobic-hydrophilic balance characteristics of lignin, improving the utilization rate of rare earth elements. In addition, the aromatic structure in the amine-alkylated lignin molecule can also absorb ultraviolet light, reducing the photolysis loss of the liquid fertilizer under strong light. This design based on biomass-derived chelating agents not only solves the problem of immobilization of rare earth elements in foliar application but also provides a new way for the high-value utilization of lignin.

[0022] (3) From the perspective of application, the chelating-rare earth composite liquid fertilizer of the present invention can effectively supplement the nutrients required during the entire growth period of navel oranges. During the sprouting period to the new shoot growth period of navel oranges, it can prevent new shoot chlorosis, promote leaf photosynthesis, and reduce citrus canker; during the flowering period to the young fruit period of navel oranges, it can promote cell division of young fruits and enhance stress resistance; during the fruit swelling period to the maturity period of navel oranges, it can maintain leaf health, promote sugar accumulation and fruit coloring. Description of the Drawings

[0023] Figure 1 Carbon spectrum of the amine-alkylated lignin prepared in Example 1. Detailed Embodiments

[0024] The following are some of the multiple possible embodiments of the present invention, aiming to provide a basic understanding of the present invention and not aiming to identify the key or decisive elements of the present invention or limit the scope to be protected. It is easy to understand that according to the technical solution of the present invention, those of ordinary skill in the art can propose other alternative implementation manners without changing the essence of the present invention. Therefore, the following detailed embodiments are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the whole of the present invention or as a limitation or restriction of the technical solution of the present invention.

[0025] The chelating-rare earth composite liquid fertilizer of the present invention contains a chelating agent, and the chelating agent is amine-alkylated lignin. The reaction formula is as follows: The amine-alkylated lignin of the present invention is prepared according to the following method: ① Dissolve small molecule lignin (molecular weight 1000 - 2000 Da) in an organic solvent, add a protonic acid as a catalyst, and then add caprolactam in an amount of 0.5 - 0.7 times the mass of lignin to obtain a reaction material.

[0026] The organic solvent is one or a combination of more than one of 1,4 - dioxane, N,N - dimethylformamide, and N,N - dimethylacetamide.

[0027] The protonic acid is one of sulfuric acid, methanesulfonic acid, and trifluoroacetic acid; the added mass of the protonic acid catalyst is 1% - 3% of the mass of small molecule lignin.

[0028] ② Heat the reaction material to 80 - 100 °C and stir - react at this temperature for 16 - 24 hours.

[0029] ③ After the reaction is completed, slowly drop the reaction solution into a 0.5 - 2 mol / L aqueous sodium bicarbonate solution to precipitate a large amount of brown - yellow precipitate. After the dropping of the reaction solution is complete, perform suction filtration, wash the solid obtained after suction filtration with distilled water, and dry it to obtain a brown powder, which is the modified amino - alkyl lignin.

[0030] In the modification reaction of lignin in the present invention, the caprolactam used has a seven - membered ring structure and has high reactivity, and can react with lignin in a high yield to obtain the target product. The obtained amino - alkylated product has a long flexible pentacarbon alkyl chain, which not only increases its processability, but also the amino group is located far from the benzene ring, with very small steric hindrance, greatly enhancing the nucleophilic property of the amino group. Subsequently, it can be further modified to form reversible covalent bonds and introduce multidentate coordination units.

[0031] (Example 1) The chelating - rare earth composite liquid fertilizer in this example comprises the following components in parts by weight: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 230 parts of chelating agent amino - alkyl lignin, 50 parts of zinc sulfate, 12 parts of low - viscosity sodium alginate, 20 parts of sodium nitrophenolate, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, and 2 parts of lanthanum chloride.

[0032] The chelating - rare earth composite liquid fertilizer in this example is prepared according to the following method: Add the above raw materials into a reaction kettle and mix them evenly. Chelate the raw materials at a temperature of 60 °C and a rotation speed of 400 rad / min for 4 h. After the reaction is completed, lower the temperature to below 30 °C to obtain a uniform liquid fertilizer.

[0033] The amino - alkyl lignin in this example is prepared according to the following method: ① Dissolve 2.0 g of small molecule lignin (the small molecule lignin in this example is obtained by extracting lignin with ethanol) in 40 mL of N,N-dimethylformamide, add sulfuric acid solution (concentration 30%), the mass of H2SO4 is 1.5% of the mass of small molecule lignin, and then add 1.2 g of caprolactam to obtain the reaction material.

[0034] There is no limitation on the feeding order of the protonic acid catalyst and caprolactam. In some embodiments, caprolactam can also be added to the small molecule lignin solution first, and then the protonic acid catalyst is added.

[0035] ② Heat the reaction material to 85 °C and stir the reaction at this temperature for 20 h.

[0036] ③ After the reaction is completed, slowly drop the reaction solution into 200 mL of 1 mol / L sodium bicarbonate aqueous solution. A large amount of brownish-yellow precipitate precipitates in the sodium bicarbonate aqueous solution. After the addition of the reaction solution is completed, carry out suction filtration, wash the solid with distilled water, and obtain 2.7 g of brown powder after drying the solid, with a yield of 81.8%.

[0037] Perform nuclear magnetic resonance carbon spectrum analysis on the obtained product. The nuclear magnetic resonance carbon spectrum of the product is shown in Figure 1 , Figure 1 In the nuclear magnetic spectrum, 173 - 175 is the characteristic peak of the ester group C=O.

[0038] (Example 2) The chelating-rare earth composite liquid fertilizer of this example includes the following components in parts by weight: 550 parts of wood vinegar, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 230 parts of amine-alkyl lignin, 50 parts of ferric sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of sodium nitrophenolate, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, and 2 parts of cerium chloride.

[0039] (Example 3) The chelating-rare earth composite liquid fertilizer of this example includes the following components in parts by weight: 550 parts of wood vinegar, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 230 parts of amine-alkyl lignin, 20 parts of ferric sulfate, 20 parts of zinc sulfate, 10 parts of manganese sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of sodium nitrophenolate, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, and 2 parts of cerium chloride.

[0040] (Examples 4 to 10) The components (parts by weight) of the chelating-rare earth composite liquid fertilizer of Examples 4 to 10 of this example are as follows in the table: .

[0041] (Example 11) The chelating-rare earth composite liquid fertilizer in this example is the same as that in Example 1, except that the aminoalkyl lignin in this example is prepared according to the following method: ① Dissolve 2.0 g of small molecule lignin in 40 mL of 1,4-dioxane, add trifluoroacetic acid, and the addition amount of trifluoroacetic acid is 1% of the mass of small molecule lignin, and then add 1.2 g of caprolactam to obtain a reaction material.

[0042] ② Heat the reaction material to 80 °C and stir and react at this temperature for 24 h.

[0043] ③ After the reaction is completed, slowly drop the reaction solution into 200 mL of 1.5 mol / L sodium bicarbonate aqueous solution. A large amount of brownish-yellow precipitate precipitates in the sodium bicarbonate aqueous solution. After the addition of the reaction solution is completed, perform suction filtration, wash the solid with distilled water, and dry the solid to obtain a brown powder, which is aminoalkyl lignin.

[0044] (Example 12) The chelating-rare earth composite liquid fertilizer in this example is the same as that in Example 1, except that the aminoalkyl lignin in this example is prepared according to the following method: ① Dissolve 2.0 g of small molecule lignin in 30 mL of N,N-dimethylformamide, add methanesulfonic acid, and the addition amount of methanesulfonic acid is 2.5% of the mass of small molecule lignin, and then add 1.4 g of caprolactam to obtain a reaction material.

[0045] ② Heat the reaction material to 95 °C and stir and react at this temperature for 18 h.

[0046] ③ After the reaction is completed, slowly drop the reaction solution into 200 mL of 2 mol / L sodium bicarbonate aqueous solution. A large amount of brownish-yellow precipitate precipitates in the sodium bicarbonate aqueous solution. After the addition of the reaction solution is completed, perform suction filtration, wash the solid with distilled water, and dry the solid to obtain a brown powder, which is aminoalkyl lignin.

[0047] (Example 13) The chelating-rare earth composite liquid fertilizer in this example is the same as that in Example 1, except that the aminoalkyl lignin in this example is prepared according to the following method: ① Dissolve 2.0 g of small molecule lignin in 20 mL of N,N-dimethylformamide, add trifluoroacetic acid, and the addition amount of trifluoroacetic acid is 1% of the mass of small molecule lignin, and then add 1 g of caprolactam to obtain a reaction material.

[0048] ② Heat the reaction material to 100 °C and stir and react at this temperature for 16 h.

[0049] ③After the reaction is completed, the reaction solution is slowly added dropwise to 200 mL of 0.5 mol / L aqueous sodium bicarbonate solution. A large amount of brownish-yellow precipitate is formed in the aqueous sodium bicarbonate solution. After the addition of the reaction solution is completed, suction filtration is carried out, and the solid is washed with distilled water. After drying the solid, a brown powder, namely aminoalkyl lignin, is obtained.

[0050] (Example 14) The chelating-rare earth composite liquid fertilizer of this example is the same as that of Example 1 in other aspects. The difference is that the aminoalkyl lignin of this example is prepared according to the following method: ①Dissolve 2.0 g of small molecule lignin in 40 mL of N,N-dimethylformamide, add sulfuric acid with the addition amount of H2SO4 being 3% of the mass of small molecule lignin, and then add 1.4 g of caprolactam to obtain the reaction material.

[0051] ②Heat the reaction material to 85 °C and stir and react at this temperature for 24 h.

[0052] ③After the reaction is completed, the reaction solution is slowly added dropwise to 200 mL of 1.5 mol / L aqueous sodium bicarbonate solution. A large amount of brownish-yellow precipitate is formed in the aqueous sodium bicarbonate solution. After the addition of the reaction solution is completed, suction filtration is carried out, and the solid is washed with distilled water. After drying the solid, a brown powder, namely aminoalkyl lignin, is obtained.

[0053] (Example 15) The chelating-rare earth composite liquid fertilizer of this example is the same as that of Example 1 in other aspects. The difference is that the aminoalkyl lignin of this example is prepared according to the following method: ①Dissolve 2.0 g of small molecule lignin in 40 mL of N,N-dimethylformamide, add methanesulfonic acid with the addition amount of methanesulfonic acid being 1.5% of the mass of small molecule lignin, and then add 1.2 g of caprolactam to obtain the reaction material.

[0054] ②Heat the reaction material to 90 °C and stir and react at this temperature for 20 h.

[0055] ③After the reaction is completed, the reaction solution is slowly added dropwise to 200 mL of 1 mol / L aqueous sodium bicarbonate solution. A large amount of brownish-yellow precipitate is formed in the aqueous sodium bicarbonate solution. After the addition of the reaction solution is completed, suction filtration is carried out, and the solid is washed with distilled water. After drying the solid, a brown powder, namely aminoalkyl lignin, is obtained.

[0056] (Test Example 1, Fertilizer efficiency experimental results of the liquid fertilizer from the budding stage to the new shoot growth stage of navel oranges) In this experimental example, the liquid fertilizer is used as a foliar fertilizer.

[0057] Experimental group 1: The chelating-rare earth composite liquid fertilizer of Example 1.

[0058] Control Group 1: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 50 parts of zinc sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of sodium nitrophenolate, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, and 2 parts of lanthanum chloride. The preparation method of the liquid fertilizer is the same as that in Example 1.

[0059] Control Group 2: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 230 parts of EDTA, 50 parts of zinc sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of sodium nitrophenolate, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, and 2 parts of lanthanum chloride. The preparation method of the liquid fertilizer is the same as that in Example 1.

[0060] Experimental Group 1, Control Group 1, and Control Group 2 were each diluted 400 times before use, and the total dosage for 100 navel oranges was about 35 L. The navel oranges used in the experiment of the chelated-rare earth composite liquid fertilizer were the red-fleshed navel orange variety, and the period from germination to new shoot growth of this variety was about 20 days. One mu of treatment was set for each of the experimental group and the control group, and sowing was carried out on the same day in early March.

[0061] The growth conditions of the navel orange experimental field from germination to new shoot growth are as follows in the table: From the application results, it can be seen that the application of the chelated-rare earth composite liquid fertilizer of the present invention has improved the chlorophyll content and photosynthesis of navel oranges. Compared with Control Group 1 without a chelating agent, the chlorophyll content of the leaves increased by about 21%, and the photosynthetic rate increased by 2.83 μmol·m⁻²·s⁻¹; compared with Control Group 2 with an EDTA chelating agent added, the chlorophyll content of the leaves increased by about 12%, and the photosynthetic rate increased by 1.9 μmol·m⁻²·s⁻¹.

[0062] (Test Example 2, Fertilizer efficiency experimental results of the liquid fertilizer from the flowering period to the young fruit period of navel oranges) In this experimental example, the liquid fertilizer was applied as a foliar fertilizer.

[0063] Experimental Group 2: The chelated-rare earth composite liquid fertilizer of Example 2.

[0064] Control Group 1: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 50 parts of ferric sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of sodium nitrophenolate, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, and 2 parts of cerium chloride. The preparation method of the liquid fertilizer is the same as that in Example 1.

[0065] Control group 2: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 230 parts of EDTA, 50 parts of ferric sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of compound nitrophenol sodium, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, 2 parts of cerium chloride. The preparation method of the liquid fertilizer is the same as that in Example 1.

[0066] Experimental group 2, control group 1 and control group 2 were each diluted 400 times before use, and the total dosage for 100 navel oranges was about 70 L. The navel orange variety used in the experiment of the chelated-rare earth composite liquid fertilizer was the red-fleshed navel orange, and the flowering period to the young fruit stage of this variety was about 50 days. One mu of treatment was set for each of the experimental group and the control group. The treatment object was 5-year-old red-fleshed navel oranges in the same orchard that were grafted in the same batch and entered the flowering stage. Healthy plants with consistent tree age, plant height, crown width and flower quantity were selected.

[0067] The growth conditions of the navel orange experimental field from the flowering period to the young fruit stage are as follows in the table: From the application results, it can be seen that both the fruit setting number and the growth rate of the transverse diameter of the young fruits of the fruit trees applying the chelated-rare earth composite liquid fertilizer of the present invention have increased. Compared with control group 1 without chelating agent, the fruit setting number per plant after 50 days has increased by about 33%, and the growth rate of the transverse diameter of the young fruits is faster; compared with control group 2 with EDTA chelating agent, the fruit setting number per plant after 50 days has increased by about 15%, and the growth rate of the transverse diameter of the young fruits has increased by about 13%.

[0068] (Test example 3, experimental results of the fertilizer efficiency of the liquid fertilizer from the fruit expansion stage to the maturity stage of navel oranges) In this experimental example, the liquid fertilizer was applied as a foliar fertilizer.

[0069] Experimental group 3: The chelated-rare earth composite liquid fertilizer of Example 3.

[0070] Control group 1: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 20 parts of ferric sulfate, 20 parts of zinc sulfate, 10 parts of manganese sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of compound nitrophenol sodium, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, 2 parts of cerium chloride. The preparation method of the liquid fertilizer is the same as that in Example 1.

[0071] Control group 2: 550 parts of wood vinegar liquid, 45 parts of potassium dihydrogen phosphate, 70 parts of dipotassium hydrogen phosphate, 230 parts of EDTA, 20 parts of ferric sulfate, 20 parts of zinc sulfate, 10 parts of manganese sulfate, 12 parts of low-viscosity sodium alginate, 20 parts of compound nitrophenol sodium, 10 parts of triacontanol milk powder, 6 parts of sodium dodecylbenzenesulfonate, 5 parts of carrageenan, 2 parts of cerium chloride. The preparation method of the liquid fertilizer is the same as that in Example 1.

[0072] The experimental group 3, control group 1 and control group 2 were each diluted 400 times before use, and the total dosage for 100 navel oranges was about 100 L. The navel orange variety used in the experiment of the chelated-rare earth compound liquid fertilizer was the red-fleshed navel orange, and the fruit expansion period to the maturity period of this variety was about 120 days. One mu of treatment was set for each of the experimental group and the control group. The treatment object was 5-year-old red-fleshed navel oranges grafted in the same batch in the same orchard and entering the fruit expansion period. Healthy plants with consistent tree age and fruit set number were selected. All plants in each experimental field took fruits at the same azimuth (east, south, west) in the middle of the tree crown, 3 fruits were taken per plant, and the total mean value of the measured data of each group was taken for analysis.

[0073] The growth conditions of the navel orange experimental field from the fruit expansion period to the maturity period are as follows: From the application results, it can be seen that the chelated-rare earth compound liquid fertilizer of the present invention can increase the fruit size and improve the fruit sweetness. Compared with the control group 1 without chelating agent, the fruit weight and sweetness have been improved; compared with the control group with EDTA chelating agent added, the fruit weight has increased by about 4.5%, and the total sugar has increased by about 6.7%.

[0074] From the above three groups of experimental results, it can be seen that the chelating agent amine alkyl lignin in the chelated-rare earth compound liquid fertilizer of the present invention improves the utilization rate of rare earth elements.

Claims

1. A chelating-rare earth composite liquid fertilizer, characterized in that It comprises the following components in parts by weight: 500 - 600 parts of wood vinegar, 40 - 50 parts of potassium dihydrogen phosphate, 60 - 80 parts of dipotassium hydrogen phosphate, 200 - 250 parts of chelating agent amine alkyl lignin, 0 - 50 parts of zinc sulfate, 0 - 50 parts of ferric sulfate, 0 - 15 parts of manganese sulfate, 6 - 12 parts of low-viscosity sodium alginate, 10 - 25 parts of sodium nitrophenolate, 5 - 15 parts of triacontanol milk powder, 2 - 8 parts of sodium dodecylbenzenesulfonate, 2 - 8 parts of carrageenan, 0.5 - 4 parts of rare earth element chloride; The structural formula of the chelating agent amine alkyl lignin is as follows: 。 2. The chelation-rare earth composite liquid fertilizer according to claim 1, characterized in that: The rare earth element chloride described above includes at least one of lanthanum chloride, cerium chloride and neodymium chloride.

3. The chelation-rare earth composite liquid fertilizer according to claim 1, wherein: The sum of the weight parts of zinc sulfate, ferric sulfate and manganese sulfate is 30 - 60 parts.

4. A method for preparing the aminoalkyl lignin as described in claim 1, characterized in that It includes the following steps: ① Dissolve small molecule lignin in an organic solvent, add a protonic acid as a catalyst, and then add caprolactam which is 0.5 - 0.7 times the mass of the lignin to obtain a reaction material; ② Heat the reaction material to 80 - 100 °C and stir and react at this temperature for 16 - 24 hours; ③ After the reaction ends, slowly drop the reacted solution into an aqueous sodium bicarbonate solution to precipitate a large amount of brownish-yellow precipitate. After the dropping of the reacted solution is complete, perform suction filtration, wash the solid obtained after suction filtration with distilled water, and dry it to obtain a brown powder, which is the modified amine alkyl lignin.

5. The preparation method of the aminoalkyl lignin according to claim 4, wherein: The molecular weight of the small molecule lignin is 1000 - 2000 Da.

6. The preparation method of the aminoalkyl lignin according to claim 4, characterized in that: In step ①, the organic solvent is one or a combination of more than one of 1,4-dioxane, N,N-dimethylformamide, and N,N-dimethylacetamide.

7. The preparation method of the aminoalkyl lignin according to claim 4, characterized in that: In step ①, the protonic acid is one of sulfuric acid, methanesulfonic acid, and trifluoroacetic acid; the added mass of the protonic acid catalyst is 1% - 3% of the mass of the small molecule lignin.

8. The preparation method of the aminoalkyl lignin according to claim 4, wherein: In step ③, the concentration of the aqueous sodium bicarbonate solution is 0.5 - 2 mol / L.

9. A preparation method of the chelate-rare earth composite liquid fertilizer as described in claim 1, characterized in that: Add 500 - 600 parts of wood vinegar, 40 - 50 parts of potassium dihydrogen phosphate, 60 - 80 parts of dipotassium hydrogen phosphate, 200 - 250 parts of chelating agent amine alkyl lignin, 0 - 50 parts of zinc sulfate, 0 - 50 parts of ferric sulfate, 0 - 15 parts of manganese sulfate, 6 - 12 parts of low-viscosity sodium alginate, 10 - 25 parts of sodium nitrophenolate, 5 - 15 parts of triacontanol milk powder, 2 - 8 parts of sodium dodecylbenzenesulfonate, 2 - 8 parts of carrageenan, 0.5 - 4 parts of rare earth element chloride into a reaction kettle. After the raw materials are mixed evenly in the kettle, chelate for 3 - 5 h at a rotation speed of 400 ± 50 rad / min and a temperature of 60 ± 10 °C, and then lower the temperature of the reacted material to below 30 °C to obtain a liquid fertilizer.

10. An amine alkyl lignin used as a chelating agent in a liquid fertilizer, the structural formula is as follows: 。

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