A bio-based compound fertilizer synergist and a preparation method thereof

Abstract

The application provides a bio-based compound fertilizer synergist and a preparation method thereof. Through aspartic acid-lysine-metal chelate compound modification and a secondary granulation method, the nutrient controlled release effect is more optimal, and the synergist and the microelement supplement are combined; the seaweed extract can activate the expression of crop stress resistance genes, and the combination of gamma-aminobutyric acid and spermidine can repair the soil and crop microecology, and the crop growth and soil conservation are considered.

Description

Technical Field

[0001] This invention belongs to the field of agricultural chemistry and bio-fertilizer technology, specifically relating to a bio-based compound fertilizer synergist and its preparation method. Background Technology

[0002] In current agricultural production, low fertilizer utilization efficiency and severe nutrient loss are widespread problems. my country accounts for about one-third of global fertilizer use, but its fertilizer utilization rate is far lower than that of developed countries. Traditional nitrogen and potassium fertilizers are easily leached or volatilized by rainwater after application in the field, causing not only huge economic losses but also environmental and agricultural problems such as eutrophication of water bodies, soil compaction, and non-physiological obstacles in crops. To address these challenges, controlled-release fertilizers, slow-release additives, and functional synergists are gradually being promoted and applied. Among these, bio-based fertilizer synergists have become a research hotspot in recent years due to their advantages of being derived from natural renewable resources, having good biocompatibility, and being biodegradable with no residue.

[0003] The existing technology CN202511703054.9 discloses a fertilizer synergist based on polyaspartic acid, fucoidan, and mannan oligosaccharide, which only achieves nutrient controlled release and root induction by constructing a complex network of the three, without involving the functions of soil microecological regulation and crop stress resistance enhancement; CN202411034688.5 uses modified polyglutamic acid and biochar as a compound, which has a certain fertilizer retention capacity, but the biochar has poor dispersibility and weak synergistic effect with other components.

[0004] Therefore, developing a bio-based compound fertilizer synergist with multiple components, a green and simple preparation process, the ability to simultaneously enhance nutrient efficiency, improve soil, and improve crop stress resistance, and with good stability of each component and no environmental residues, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a bio-based compound fertilizer synergist and its preparation method. By screening multiple components and optimizing their ratios, a synergistic system of "controlled nutrient release + micronutrient supplementation + enhanced stress resistance" is constructed. At the same time, the preparation process is optimized to achieve retention of component activity and greening of the process. This solves the technical defects of existing synergists, such as single function, poor component compatibility, easy loss of microbial activity, and complex preparation process. It improves fertilizer utilization, improves the soil environment, enhances crop stress resistance, and leaves no harmful residues throughout the process, meeting the needs of green agricultural development.

[0006] Specifically, the present invention is achieved through the following technical solution: A bio-based compound fertilizer synergist, comprising the following raw material components by weight: The composition includes 35-55 parts aspartic acid, 10-30 parts lysine, 2-6 parts metal elements, 25-45 parts seaweed extract, 0.3-1.0 parts spermidine, 0.3-1.0 parts γ-aminobutyric acid, and 2-7 parts binder. The binder is a mixture of maltodextrin and sodium carboxymethyl cellulose at a mass ratio of 3-5:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 at a weight ratio of 1:0.5-1:1-1.5.

[0007] Preferably, the bio-based compound fertilizer synergist comprises, by weight, the following raw material components: The mixture contains 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder. The binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0008] In a second aspect, the present invention provides a method for preparing a bio-based compound fertilizer synergist, specifically comprising the following steps: (1) Dissolve aspartic acid and lysine in deionized water, stir until completely dissolved, adjust pH, add phosphoric acid catalyst to the mixed amino acid solution, heat and stir, then cool to room temperature, add deionized water to dilute, filter to remove insoluble impurities, then concentrate under reduced pressure, and finally freeze dry and pulverize to obtain aspartic acid-lysine powder. (2) Add water to the metal element and stir until it is completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add the aspartic acid-lysine powder obtained in step (1) to the above aqueous solution and continue stirring until it is completely dissolved to obtain a mixture of aspartic acid-lysine-metal salt. Adjust the pH and stir the mixture in a constant temperature water bath for 1-2 hours. After the reaction is completed, spray dry to obtain aspartic acid-lysine-metal chelate powder. (3) Mix the aspartic acid-lysine-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and some binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and sieve; then mix with the remaining binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and sieve to obtain the bio-based compound fertilizer synergist.

[0009] Preferably, in step (1), the amount of phosphoric acid catalyst added is 2% to 4% of the total mass of the mixed amino acids; Preferably, in step (1), the pH is adjusted to 7.0–8.0; Preferably, the heating temperature in step (1) is 160–190°C; Preferably, the stirring is carried out for 3 to 5 hours in step (1); Preferably, in step (2), the pH is adjusted to 7.0–8.0; Preferably, the temperature in step (2) is kept constant at 35–45°C; Preferably, the reaction is stirred for 1-2 hours in step (2); Preferably, in step (3), the amount of binder added during the first granulation is 65-75% of the total amount; Preferably, in step (3), the material is sieved through a mesh of 80-100.

[0010] In a preferred embodiment, a method for preparing a bio-based compound fertilizer synergist specifically includes the following steps: (1) Dissolve aspartic acid and lysine in deionized water, stir until completely dissolved, adjust pH to 7.0-8.0, add 2%-4% phosphoric acid catalyst to the mixed amino acid solution, heat to 160-190℃, stir for 3-5 hours, then cool to room temperature, add deionized water to dilute, filter to remove insoluble impurities, then concentrate under reduced pressure, and finally freeze dry and pulverize to obtain aspartic acid-lysine powder; (2) Add water to the metal element and stir until completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add the aspartic acid-lysine powder obtained in step (1) to the above aqueous solution and continue stirring until completely dissolved to obtain a mixture of aspartic acid-lysine-metal salt. Adjust the pH to 7.0-8.0 and stir in a constant temperature water bath at 35-45℃ for 1-2 hours. After the reaction is completed, spray dry to obtain aspartic acid-lysine-metal chelate powder. (3) Mix the aspartic acid-lysine-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and 65-75% binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and pass through an 80-100 mesh sieve; then mix with the remaining 35-45% binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain the bio-based compound fertilizer synergist.

[0011] The beneficial effects of this invention are: The modified aspartic acid-lysine-metal chelate compound, along with the secondary granulation method, enhances the controlled release of nutrients, combining chelation enhancement and micronutrient supplementation. Seaweed extract can activate the expression of crop stress-resistance genes, and the combined use of γ-aminobutyric acid and spermidine can repair the soil and crop microecology, taking into account both crop growth and soil maintenance. Detailed Implementation

[0012] The present invention will be further illustrated below through embodiments. It should be understood that the embodiments of the present invention are merely illustrative and not intended to limit the invention. Therefore, any simple modifications to the present invention based on the method described herein are within the scope of protection claimed by the present invention. Unless otherwise stated, the raw materials and reagents used in the embodiments are commercially available products, and reagents, instruments, or operating procedures not described herein are all matters that can be conventionally determined by those skilled in the art.

[0013] Example 1 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0014] Its preparation method includes the following steps: (1) Dissolve aspartic acid and lysine in deionized water, stir until completely dissolved, adjust pH to 7.5, add 3% phosphoric acid catalyst to the mixed amino acid solution, heat to 180℃, stir for 3-5 hours, then cool to room temperature, add deionized water to dilute, filter to remove insoluble impurities, then concentrate under reduced pressure, and finally freeze dry and pulverize to obtain aspartic acid-lysine powder; (2) Add water to the metal element and stir until completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add the aspartic acid-lysine powder obtained in step (1) to the above aqueous solution and continue stirring until completely dissolved to obtain a mixture of aspartic acid-lysine-metal salt. Adjust the pH to 7.5 and stir the mixture in a 40°C constant temperature water bath for 1-2 hours. After the reaction is completed, spray dry to obtain aspartic acid-lysine-metal chelate powder. (3) Mix the aspartic acid-lysine-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and 70% binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and pass through an 80-100 mesh sieve; then mix with the remaining 30% binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain the bio-based compound fertilizer synergist.

[0015] Example 2 The ingredients include 35 parts aspartic acid, 30 parts lysine, 6 parts metal elements, 45 parts seaweed extract, 0.3 parts spermidine, 1.0 part γ-aminobutyric acid, and 7 parts binder. The binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 3:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.5:1.

[0016] A bio-based compound fertilizer synergist was prepared according to the method in Example 1.

[0017] Example 3 The ingredients include 55 parts aspartic acid, 10 parts lysine, 2 parts metal elements, 25 parts seaweed extract, 1.0 part spermidine, 0.3 parts γ-aminobutyric acid, and 2 parts binder. The binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 5:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:1:1.5.

[0018] A bio-based compound fertilizer synergist was prepared according to the method in Example 1.

[0019] Comparative Example 1 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0020] Its preparation method includes the following steps: (1) Add water to the metal element and stir until completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add aspartic acid to the above aqueous solution and continue stirring until completely dissolved to obtain an aspartic acid-metal salt mixture. Adjust the pH to 7.5 and stir the mixture in a 40°C constant temperature water bath for 1-2 hours. After the reaction is complete, spray dry to obtain aspartic acid-lysine-metal chelate powder. (2) Mix aspartic acid-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and 70% binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and pass through an 80-100 mesh sieve; then mix with the remaining 30% binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain bio-based compound fertilizer synergist.

[0021] Comparative Example 2 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0022] A bio-based compound fertilizer synergist was prepared according to the method in Example 1.

[0023] Comparative Example 3 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0024] Comparative Example 4 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1.

[0025] Its preparation method includes the following steps: (1) Dissolve aspartic acid and lysine in deionized water, stir until completely dissolved, adjust pH to 7.5, add 3% phosphoric acid catalyst to the mixed amino acid solution, heat to 180℃, stir for 3-5 hours, then cool to room temperature, add deionized water to dilute, filter to remove insoluble impurities, then concentrate under reduced pressure, and finally freeze dry and pulverize to obtain aspartic acid-lysine powder; (2) Mix aspartic acid-lysine powder, seaweed extract, spermidine, γ-aminobutyric acid and 70% binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and pass through an 80-100 mesh sieve; then mix with the remaining 30% binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain a bio-based compound fertilizer synergist.

[0026] Comparative Example 5 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0027] Its preparation method includes the following steps: (1) Add water to the metal element and stir until it is completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add aspartic acid and lysine to the above aqueous solution and continue stirring until it is completely dissolved to obtain a mixed solution. Adjust the pH to 7.5 and stir the reaction in a 40℃ constant temperature water bath for 1-2 hours. After the reaction is completed, spray dry to obtain chelate powder. (2) Mix the chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and 70% binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and pass through an 80-100 mesh sieve; then mix with the remaining 30% binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain the bio-based compound fertilizer synergist.

[0028] Comparative Example 6 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0029] Its preparation method includes the following steps: (1) Dissolve aspartic acid and lysine in deionized water, stir until completely dissolved, adjust pH to 7.5, add 3% phosphoric acid catalyst to the mixed amino acid solution, heat to 180℃, stir for 3-5 hours, then cool to room temperature, add deionized water to dilute, filter to remove insoluble impurities, then concentrate under reduced pressure, and finally freeze dry and pulverize to obtain aspartic acid-lysine powder; (2) Add water to the metal element and stir until completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add the aspartic acid-lysine powder obtained in step (1) to the above aqueous solution and continue stirring until completely dissolved to obtain a mixture of aspartic acid-lysine-metal salt. Adjust the pH to 7.5 and stir the mixture in a 40°C constant temperature water bath for 1-2 hours. After the reaction is completed, spray dry to obtain aspartic acid-lysine-metal chelate powder. (3) Mix the aspartic acid-lysine-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and binder evenly, add an appropriate amount of purified water, granulate, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain the bio-based compound fertilizer enhancer.

[0030] Comparative Example 7 A bio-based compound fertilizer synergist comprises the following components in parts by weight: 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder; wherein the binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.2.

[0031] Its preparation method includes the following steps: (1) Dissolve aspartic acid and lysine in deionized water, stir until completely dissolved, adjust pH to 9, add 1% phosphoric acid catalyst to the mixed amino acid solution, heat to 180℃, stir for 3-5 hours, then cool to room temperature, add deionized water to dilute, filter to remove insoluble impurities, then concentrate under reduced pressure, and finally freeze dry and pulverize to obtain aspartic acid-lysine powder. (2) Add water to the metal element and stir until completely dissolved to obtain an aqueous solution of the metal element. Keep it at room temperature for later use. Slowly add the aspartic acid-lysine powder obtained in step (1) to the above aqueous solution and continue stirring until completely dissolved to obtain a mixture of aspartic acid-lysine-metal salt. Adjust the pH to 9 and stir the mixture in a 50°C constant temperature water bath for 1-2 hours. After the reaction is completed, spray dry to obtain aspartic acid-lysine-metal chelate powder. (3) Mix the aspartic acid-lysine-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and 40% binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and pass through an 80-100 mesh sieve; then mix with the remaining 60% binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and pass through an 80-100 mesh sieve to obtain the bio-based compound fertilizer synergist.

[0032] Verification Example: Nitrogen fertilizer controlled release performance test 1000g of samples prepared in Examples 1-3 and Comparative Examples 1-7 were weighed, placed in permeable nonwoven bags and sealed, and then immersed in 250mL of deionized water. The bags were then allowed to stand at a constant temperature of 25℃. The water was changed every 24 hours, and water samples from the previous cycle were collected. The total nitrogen content was determined using the Kjeldahl method. The experiment lasted for 28 days. The nitrogen release of each sample at different time points was recorded, and the time required to reach 80% cumulative release, i.e., the controlled-release duration, was calculated. The results are shown in Table 1 below.

[0033] Table 1 Controlled Release Time The results showed that Examples 1 to 3 all exhibited good nitrogen controlled release performance. Comparative Example 1 did not add lysine, and Comparative Example 4 did not undergo reaction treatment with aspartic acid and lysine, resulting in structural loss. The initial nitrogen release was rapid, and the controlled release duration was short. Although Comparative Examples 6 and 7 had the same formula, Comparative Example 6 did not undergo secondary granulation, and Comparative Example 7 had different method parameters, which also showed a shortened controlled release time.

[0034] Crop yield increase test Field comparison trials were conducted on samples prepared in Examples 1-3 and Comparative Examples 1-7. The control group was not treated with synergists. The experimental crop was wheat. The soil fertility of the experimental plots was uniform, and the field management measures such as seeding rate, irrigation, and pest and disease control were consistent. The experimental area of ​​each group was 100 m². The experimental results are shown in Table 2 below: Table 2 Soil modification test A random sample of soil was divided into 11 equal portions. The organic matter and microbial content of the soil were first tested. Then, samples from Examples 1-3 and Comparative Examples 1-7 were evenly spread onto 10 portions of soil, respectively. The control group received no synergist. The soil was immediately deep-plown to a depth of 25-30 cm to mix the fertilizer and soil. Sixty days after fertilization, soil samples from the topsoil layer (0-20 cm) were collected using an "S-shaped route," mixed thoroughly, air-dried, pulverized, and sieved through a 3-5 mm sieve. The soil organic matter content was tested according to GB 9834-1988 standard; the microbial content was tested according to GB / T39228-2020 standard, "Determination of Soil Microbial Biomass, Fumigation Extraction Method." The experimental results are shown in Table 3 below. Table 3 The synergists in Examples 1-3 can effectively increase the total amount of soil microorganisms, while in Comparative Example 2, no γ-aminobutyric acid was added, which greatly reduced the effect of the synergist.

Claims

1. A bio-based compound fertilizer synergist, characterized in that, The components include the following parts by weight: The composition includes 35-55 parts aspartic acid, 10-30 parts lysine, 2-6 parts metal elements, 25-45 parts seaweed extract, 0.3-1.0 parts spermidine, 0.3-1.0 parts γ-aminobutyric acid, and 2-7 parts binder. The binder is a mixture of maltodextrin and sodium carboxymethyl cellulose at a mass ratio of 3-5:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 at a weight ratio of 1:0.5-1:1-1.

5.

2. The fertilizer synergist according to claim 1, characterized in that, The components include the following parts by weight: The mixture contains 45 parts aspartic acid, 20 parts lysine, 4 parts metal elements, 35 parts seaweed extract, 0.6 parts spermidine, 0.6 parts γ-aminobutyric acid, and 4.5 parts binder. The binder is a mixture of maltodextrin and sodium carboxymethyl cellulose in a mass ratio of 4:1, and the metal elements are a mixture of FeCl3, CaCl2, and ZnCl2 in a weight ratio of 1:0.8:1.

2.

3. A method for preparing the fertilizer synergist according to any one of claims 1-2, characterized in that, The steps include: 1) Dissolving aspartic acid and lysine in deionized water, stirring until completely dissolved, adjusting the pH, adding phosphoric acid catalyst to the mixed amino acid solution, heating and stirring, then cooling to room temperature, adding deionized water to dilute, filtering to remove insoluble impurities, then concentrating under reduced pressure, and finally pulverizing after freeze drying to obtain aspartic acid-lysine powder. 2) Add water to the metal element and stir until completely dissolved to obtain an aqueous solution of the metal element, which is then kept at room temperature. Slowly add the aspartic acid-lysine powder obtained in step 1) to the above aqueous solution and continue stirring until completely dissolved to obtain a mixture of aspartic acid-lysine-metal salt. Adjust the pH and stir the mixture in a constant temperature water bath for 1-2 hours. After the reaction is complete, spray dry to obtain aspartic acid-lysine-metal chelate powder. 3) Mix aspartic acid-lysine-metal chelate powder, seaweed extract, spermidine, γ-aminobutyric acid and some binder evenly, add an appropriate amount of purified water, perform the first granulation, dry and crush, and sieve; then mix with the remaining binder, add an appropriate amount of purified water, perform the second granulation, dry the wet granules, granulate, and sieve to obtain bio-based compound fertilizer synergist.

4. The preparation method according to claim 3, characterized in that, In step 1), the amount of phosphoric acid catalyst added is 2% to 4% of the total mass of the mixed amino acids.

5. The preparation method according to claim 3, characterized in that, In step 1), adjust the pH to 7.0–8.

0.

6. The preparation method according to claim 3, characterized in that, The heating temperature in step 1) is 160-190℃.

7. The preparation method according to claim 3, characterized in that, In step 2), adjust the pH to 7.0–8.

0.

8. The preparation method according to claim 3, characterized in that, Step 2) Maintain a constant temperature of 35-45℃.

9. The preparation method according to claim 3, characterized in that, In step 3), the amount of binder added during the first granulation is 65-75% of the total amount.

10. The preparation method according to claim 3, characterized in that, In step 3), sieve through an 80-100 mesh screen.

Images