Preparation process of organic water-soluble fertilizer containing polymeric amino acid

Abstract

The invention relates to the technical field of nutrient synergistic chelation and slow release, in particular to a preparation process of an organic water-soluble fertilizer containing polymeric amino acid, which comprises the following steps: preparing the polymeric amino acid, modified potassium fulvate, nanoscale microelement chelate and other raw materials in percentage by weight, and further comprises a bioactive enzyme compound; the preparation method comprises the following steps: modifying potassium fulvate, and adding nano titanium dioxide and carbon nanotubes; preparing a chelate, and adding a novel surfactant; when the compound is synthesized, biological active enzyme is added; finally, mixing and preparing, sequentially adding the materials, stirring, adding the preservative, and filtering to obtain the water-soluble fertilizer, and each step has clear temperature, time and operation requirements. The water-soluble fertilizer is scientific in formula, polymeric amino acid and the like have a synergistic effect, and the utilization rate of the fertilizer is increased; the water-retaining agent is good in water retention, and the biological active enzyme improves the soil; the preparation process is stable and environment-friendly, can improve crop yield and quality, reduces pollution, and brings economic and ecological double benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nutrient synergistic chelation and slow-release technology, in particular to a preparation process of an organic water-soluble fertilizer containing polyamino acid. BACKGROUND

[0002] With the rapid development of modern agriculture, there is an increasing demand for efficient and environmentally friendly fertilizers. Organic water-soluble fertilizers have become a research hotspot in the fertilizer field due to their ability to be quickly absorbed by crops, improve soil structure, and increase fertilizer utilization. However, current organic water-soluble fertilizers on the market still have many problems and cannot meet the needs of sustainable development of modern agriculture. Traditional organic water-soluble fertilizers often have single nutrient composition, which cannot meet the needs of crops for multiple nutrients at different growth stages. Most products only focus on the addition of nitrogen, phosphorus, and potassium, and the chelation process and addition amount of iron, zinc, and manganese are not scientific, which leads to the fixation of trace elements in the soil and makes it difficult for crops to effectively absorb and utilize them, affecting the normal growth and quality improvement of crops.

[0003] Existing organic water-soluble fertilizers lack effective active ingredients and mechanisms of action. Although some products add humic acid, amino acid, and other substances, the effect of these ingredients is limited and cannot significantly improve the utilization rate of fertilizers and the stress resistance of crops. For example, ordinary humic acid degrades quickly in the soil, and its effect on soil structure improvement and nutrient slow-release is not durable; conventional amino acid has low stability and is easily decomposed, resulting in low absorption rate and poor effect on crop growth regulation and stress resistance improvement.

[0004] Water retention is also one of the shortcomings of existing organic water-soluble fertilizers. Many products have improper selection of water retention agents or insufficient addition amount. In dry or high-temperature water-deficient environments, nutrients cannot be ionized in water, and water cannot be used as a carrier to transport nutrients to plant roots, leading to the loss of fertilizer solution and the inability to continuously provide water and nutrients for crops, resulting in serious waste of fertilizers and increased cost and labor intensity for farmers. The existing preparation process of organic water-soluble fertilizers has deficiencies. Some processes perform poorly in environmental friendliness and resource utilization efficiency, such as high energy consumption and high waste discharge during production, which do not meet the requirements of green agricultural development.

[0005] In recent years, polyamino acid has gradually attracted attention in the field of fertilizers, but its application method and effect still have room for improvement. The current organic water-soluble fertilizer based on polyamino acid still has great potential for improvement in formula design, synergistic effect of active ingredients, and preparation process optimization. It is urgent to develop an innovative, efficient, and environmentally friendly preparation process of an organic water-soluble fertilizer containing polyamino acid to solve the problems in the existing technology. SUMMARY

[0006] (1) Technical problems solved In view of the deficiencies of the prior art, the present invention provides a preparation process of an organic water-soluble fertilizer containing polyamino acid.

[0007] (2) Technical solution A preparation process of an organic water-soluble fertilizer containing polyamino acid, the preparation steps are as follows: S1. Raw material preparation: Prepare, by weight percentage, 15%-25% of polyamino acid, 10%-18% of modified potassium fulvic acid, 8%-15% of nano-scale trace element chelate, 5%-12% of a novel plant growth regulating complex composed of a γ-aminobutyric acid-salicylic acid conjugate and a chitosan oligosaccharide-brassinolide complex in a mass ratio of 1:1 to 2:1, 3%-8% of an acrylamide-acrylic acid-nano-montmorillonite graft copolymer water retaining agent, 2%-5% of a bioactive enzyme complex, and the balance water; the synthetic reaction formula for the γ-aminobutyric acid-salicylic acid conjugate is: The bioactive enzyme complex is composed of a urease inhibitor, a phosphatase activator and a cellulase in a mass ratio of (1-1.5):(0.8-1.2):(0.5-1); S2, potassium fulvic acid modification: add modified potassium fulvic acid into a reactor, heat it to 50-60°C, add nano-titanium dioxide and carbon nanotubes modified with potassium fulvic acid, stir and react for 1-2 hours to obtain a modified product; S3, chelate preparation: nano-scale trace element chelate raw materials are mixed in proportion, deionized water is added to prepare a solution with a concentration of 100-200 g / L, and a novel surfactant is added to form a nano-scale trace element chelate solution, wherein the novel surfactant is a mixture of alkyl glycoside and Tween-80 in a mass ratio of 2:1; S4, complex synthesis: prepare γ-aminobutyric acid-salicylic acid conjugate and chitosan oligosaccharide-brassinolide complex respectively, mix them at a mass ratio of 1-2:1, add the bioactive enzyme complex, and mix well; S5, mixing and preparation: add the remaining water to the reactor, and add the chitosan oligosaccharide-brassinolide complex, nano-scale trace element chelate solution, γ-aminobutyric acid-salicylic acid conjugate and chitosan oligosaccharide-brassinolide complex, polyamino acid, water retaining agent in sequence, add preservatives, mix well, and filter through a 1-5 μm precision filter.

[0008] Preferably, the polyamino acid is prepared by a microbial fermentation method, wherein the fermentation strains are a mixture of Bacillus and Lactobacillus in a volume ratio of 1-2:1, the fermentation temperature is 30-35°C, the fermentation time is 3-5 days, the fermentation medium formula is: glucose 2%-5%, peptone 1%-3%, yeast extract 0.5%-1.5%, sodium chloride 0.5%-1%, and the balance is water, and the pH is adjusted to 7.0-7.2 with 1 mol / L sodium hydroxide solution; the fermentation broth is centrifuged at 8000 r / min for 15 minutes, the supernatant is concentrated with an ultrafiltration membrane with a molecular weight cutoff of 3000Da, and freeze-dried to obtain polyamino acid powder. The average molecular weight of polyamino acid is 5000-10000 Da, as determined by gel permeation chromatography; its infrared spectrum shows characteristic peaks at 3400 cm⁻¹ (-NH2 / -OH stretching vibration), 1650 cm⁻¹ (amide I band), and 1540 cm⁻¹ (amide II band). Its calcium ion chelating capacity is ≥90%, and its viscosity retention rate in 1 mol / L NaCl solution is ≥85%.

[0009] Preferably, the modified potassium fulvic acid is prepared by reacting potassium fulvic acid with a 10%-20% by mass ferrous sulfate solution and a 5%-10% by mass hydrogen peroxide solution at 60-70° C. for 1-2 hours, and nitrogen is introduced for protection during the reaction.

[0010] Preferably, in the acrylamide-acrylic acid-nano-montmorillonite graft copolymer water-retaining agent, the mass ratio of acrylamide, acrylic acid and nano-montmorillonite is 3-5:2-4:1-2, the grafting reaction initiator is an ammonium persulfate-sodium bisulfite redox system, and the initiator dosage is 0.5%-1% of the total monomer mass.

[0011] Preferably, in the chitosan oligosaccharide-brassinolide complex, the deacetylation degree of chitosan oligosaccharide is 80%-90%, the polymerization degree is 5-10, the reaction solvent is dimethyl sulfoxide, the reaction temperature is 25-30°C, the reaction time is 6-8 hours, and the preparation method is: chitosan oligosaccharide is dissolved in dimethyl sulfoxide to prepare a 100g / L solution, and brassinolide is dissolved in dimethyl sulfoxide to prepare a 50g / L solution, chitosan oligosaccharide and brassinolide are mixed at a mass ratio of 5-10:1, and magnetically heated at 25-30°C. The reaction was stirred vigorously, and the reaction solution was precipitated with deionized water, washed with ethanol, and dried in vacuo to obtain a complex. H NMR spectroscopy revealed that in DMSO-d6 solvent, the chitosan oligosaccharide ring proton peak coexisted with the brassinolide methyl proton peak, and a characteristic proton peak of amide bond connection appeared. Thermogravimetric analysis (TGA) showed that its thermal decomposition temperature was 20-30°C higher than that of chitosan oligosaccharide. In a rice high temperature resistance experiment, a 0.5 g / L solution increased the chlorophyll content by 25% and reduced the malondialdehyde content by 30%.

[0012] Preferably, the nano-titanium dioxide has a particle size of 20-50 nm, and its surface is double-layered with silane coupling agent KH570 and polydopamine; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-30 nm, a length of 1-10 μm, and are carboxylated.

[0013] Preferably, the preparation of the organic water-soluble fertilizer containing polyurethane foam described in any one of the above items includes the following equipment and operations: A high-precision electronic scale is used to weigh the raw materials, with an error controlled within ±0.1%. The weighing of the bioactive enzyme complex must be carried out in a low-temperature environment. A reactor equipped with a temperature control device, a stirrer, and a nitrogen inlet device is used for potassium fulvate modification. The temperature control accuracy is ±1°C, the stirring speed can be adjusted within the range of 50-300 rpm, and the nitrogen inlet rate is 0.5-1 L / min. The chelate preparation was performed using a pH meter, a constant temperature water bath, and an ultrasonic oscillator. The pH meter had an accuracy of ±0.01, the constant temperature water bath had a temperature control accuracy of ±0.5°C, the ultrasonic oscillator had a power of 200-300W, and a frequency of 20-40kHz. A magnetic stirrer and a low temperature circulation device were used for complex synthesis. The stirring speed was stabilized at 100-200 r / min, and the low temperature circulation device controlled the temperature at 30-40°C with a fluctuation range of ±0.5°C. A mixing reactor equipped with a multi-stage stirring paddle, an online viscometer and a preservative adding device is used for mixing and preparation. The stirring paddle speed can be adjusted in stages, the online viscometer monitors the viscosity in real time, the preservative adding device can accurately control the addition amount, and is equipped with a 1-5μm precision filter for filtration.

[0014] Preferably, the reactor is made of stainless steel 316L lined with polytetrafluoroethylene to prevent material corrosion, and the inner wall of the reactor is polished with a roughness Ra≤0.8μm.

[0015] Preferably, the precision filter adopts a cross-flow filtration method, the filtration pressure is controlled at 0.1-0.3 MPa, and the filtration flux is 5-10 L / (m²·h·MPa).

[0016] Preferably, after the mixing is completed, a UV-visible spectrophotometer is used to quickly detect the content of active ingredients in the water-soluble fertilizer to ensure that the product quality meets the standards.

[0017] (3) Beneficial technical effects Compared with the existing technology, the beneficial effects of the present invention are: 1. Polyamino acid and modified potassium fulvic acid work synergistically to effectively chelate nutrients in the soil, reducing nutrient loss and improving fertilizer utilization. The addition of this new plant growth regulator compound not only promotes crop root growth and enhances nutrient absorption, but also improves crop stress resistance, enabling crops to maintain optimal growth in harsh environments such as drought, high temperatures, and low temperatures.

[0018] 2. Acrylamide-acrylic acid-nano-montmorillonite graft copolymer water-retaining agent has excellent water-retaining capacity. It can form a water-retaining network structure in the soil, reduce water evaporation, and continuously provide water for crops. It is especially suitable for agricultural production in arid areas or water-scarce areas.

[0019] 3. The addition of a bioactive enzyme complex regulates soil microbial activity, inhibiting urease activity to reduce nitrogen loss, activating phosphatase to promote phosphorus release, and cellulase to promote the decomposition of organic matter in the soil, improving soil structure and enhancing soil fertility. Precise control of reaction conditions and the use of advanced equipment ensure the stability and uniformity of product quality, effectively reducing batch-to-batch variability. Furthermore, the use of environmentally friendly raw materials and green production methods in the process reduces energy consumption and waste emissions, meeting the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a process flow chart for preparing an organic water-soluble fertilizer containing polyamino acid; Figure 2 is a bar graph comparing fertilizer utilization rate and crop yield increase rate in the embodiment and the comparative example; Figure 3 1. It is a line graph comparing soil water retention rate and soil organic matter improvement rate of the embodiment and the comparative example; Figure 4 It is a bar graph comparing the unit area fertilizer cost and per mu income increase of the embodiment and the comparative example. DETAILED DESCRIPTION

[0021] according to Figures 1 to 4 , the specific implementation of the present invention is as follows: Example 1

[0022] Raw material preparation: By weight, weigh 15% polyamino acid, 18% modified potassium fulvic acid, 15% nano-scale trace element chelate, 5% novel plant growth regulator complex (with a 1:1 mass ratio of γ-aminobutyric acid-salicylic acid conjugate to chitosan oligosaccharide-brassinolide complex), 3% acrylamide-acrylic acid-nanomontmorillonite graft copolymer water retainer, 2% bioactive enzyme complex, and the balance water. Polyamino acid was fermented using a 1:1 volume ratio of Bacillus and Lactobacillus at 30°C for 5 days, resulting in an average molecular weight of 5000 Da. The fermentation medium consisted of 3% glucose, 2% peptone, 1% yeast extract, 0.5% sodium chloride, and a pH of 7.0. The fermentation broth was concentrated by ultrafiltration and freeze-dried to obtain the product. Modified potassium fulvic acid was prepared by reacting potassium fulvic acid with a 10% ferrous sulfate solution and a 5% hydrogen peroxide solution at 60°C for 2 hours under nitrogen protection. Nano-scale trace element chelates are ethylenediaminetetraacetic acid chelates of iron, zinc and manganese, with a particle size of 50nm.

[0023] Potassium fulvic acid modification: Add the modified potassium fulvic acid into the reactor, raise the temperature to 50°C, add 5% by mass of modified potassium fulvic acid of nano-titanium dioxide (particle size 20 nm, modified with silane coupling agent KH570 and polydopamine double layer) and 2% of carboxylated multi-walled carbon nanotubes (tube diameter 10 nm, length 1 μm), and stir to react for 2 hours.

[0024] Preparation of chelate: Mix the raw materials of nano-scale trace element chelate, add deionized water to make a 100 g / L solution, add 0.5% of a new surfactant (alkyl glycoside and Tween-80 in a mass ratio of 2:1), adjust the pH to 6, and stir the reaction at 50°C for 3 hours.

[0025] Complex synthesis: γ-aminobutyric acid-salicylic acid conjugate and chitosan oligosaccharide-brassinolide complex were prepared separately and mixed in a mass ratio of 1:1. During the preparation, 10 g of chitosan oligosaccharide and 2 g of brassinolide were dissolved in dimethyl sulfoxide and reacted for 6 hours. After vacuum drying, a white powder was obtained. In a wheat rooting experiment, a 10 mg / L solution of the powder increased root length by 40%. A bioactive enzyme complex (urease inhibitor, phosphatase activator and cellulase in a mass ratio of 1:0.8:0.5) was added and stirred evenly at 30°C and 100 r / min.

[0026] Mixing preparation: add the remaining amount of water to the reactor, heat to 40°C, add the above materials in sequence, stir at 300r / min for 2 hours, add 0.1% preservative (potassium sorbate and sodium benzoate in a mass ratio of 1:1), filter through a 1μm precision filter to obtain an organic water-soluble fertilizer containing polyamino acid.

[0027] Example 2 Raw materials: 20% polyamino acid, 15% modified potassium fulvate, 12% nano-scale trace element chelate, 8% novel plant growth regulator complex (γ-aminobutyric acid-salicylic acid conjugate to chitosan oligosaccharide-brassinolide complex in a 1.5:1 weight ratio), 5% water retainer, 3% bioactive enzyme complex, and the balance water. Polyamino acid fermentation was performed at 32°C for 4 days, resulting in an average molecular weight of 7000 Da. Modified potassium fulvate was reacted with 15% ferrous sulfate solution and 7% hydrogen peroxide solution at 65°C for 1.5 hours. The nano-scale trace element chelate had a particle size of 70 nm.

[0028] Potassium fulvic acid modification: The reactor was heated to 55°C, and 7% nano-titanium dioxide (particle size 30 nm) and 3% carbon nanotubes (tube diameter 20 nm, length 5 μm) were added and stirred for 1.5 hours.

[0029] Preparation of chelate: Prepare a 150 g / L solution, add 0.7% of the new surfactant, adjust the pH to 6.5, and react at 55°C for 2.5 hours.

[0030] Complex synthesis: complex mass ratio 1.5:1, bioactive enzyme complex mass ratio 1.2:1:0.7, 35°C, 150 r / min stirring.

[0031] Mixing preparation: add water at 45℃, add materials in sequence, stir at 350r / min for 1.5 hours, add 0.2% preservative, and filter through a 3μm filter.

[0032] Example 3 Raw materials: 25% polyamino acid, 10% modified potassium fulvate, 8% nano-scale trace element chelate, 12% novel plant growth regulator complex (γ-aminobutyric acid-salicylic acid conjugate to chitosan oligosaccharide-brassinolide complex in a 2:1 mass ratio. The chitosan oligosaccharide-brassinolide complex was synthesized using 20g chitosan oligosaccharide and 2g brassinolide, with a composite ion peak at m / z = 1280 detected by ESI-MS), 8% water-retaining agent, 5% bioactive enzyme complex, and the balance water. Polyamino acid was fermented at 35°C for 3 days to an average molecular weight of 10,000 Da. Modified potassium fulvate was reacted with 20% ferrous sulfate solution and 10% hydrogen peroxide solution at 70°C for 1 hour. The nano-scale trace element chelate particle size was 100 nm.

[0033] Potassium fulvic acid modification: Add 10% nano-titanium dioxide (particle size 50 nm) and 5% carbon nanotubes (tube diameter 30 nm, length 10 μm) at 60°C and stir for 1 hour.

[0034] Preparation of chelate: Prepare a 200 g / L solution, add 1% new surfactant, adjust the pH to 7, and react at 60°C for 2 hours.

[0035] Complex synthesis: complex mass ratio 2:1, bioactive enzyme complex mass ratio 1.5:1.2:1, stirring at 40°C and 200 r / min.

[0036] Mixing preparation: add water at 50℃, add materials in sequence, stir at 400r / min for 1 hour, add 0.3% preservative, and filter through a 5μm filter.

[0037] Comparative Example The organic water-soluble fertilizer produced by Shandong Yizhonghe is used, wherein the effective ingredients of the fertilizer are nitrogen, phosphorus and potassium ≥100 g / L, humic acid ≥120 g / L, and trace elements ≥2 g / L, and does not contain the novel plant growth regulating complex, bioactive enzyme complex and other ingredients of the present invention.

[0038] Performance Testing Examples 1 to 3 are significantly better than the comparative examples in terms of fertilizer utilization rate, crop yield increase rate, soil water retention rate and soil organic matter content improvement rate. Among them, Example 3 performed the best, with a fertilizer utilization rate of 88%, a crop yield increase rate of 30%, a soil water retention rate of 80%, and a soil organic matter content increase of 25%. In comparison, the various indicators of the comparative example were significantly lower, with a fertilizer utilization rate of only 60%, a crop yield increase rate of 10%, a soil water retention rate of 50%, and a soil organic matter content increase of only 5%. Examples 1 and 2 also showed excellent performance, with fertilizer utilization rates of 80% and 85%, crop yield increases of 20% and 25%, soil water retention rates of 70% and 75%, and organic matter content increases of 15% and 20%. These data fully demonstrate the significant advantages of the new fertilizer in improving agricultural efficiency and soil improvement.

[0039] The comprehensive comparison table of fertilizer performance of the embodiment and the comparative example is as follows: Table 1 project Example 1 Example 2 Example 3 Comparative Example Fertilizer utilization rate (%) 80 85 88 60 Crop yield increase rate (%) 20 25 30 10 Soil water retention rate (%) 70 75 80 50 Soil organic matter improvement rate (%) 15 20 25 5 Stress resistance score (1-10 points) 8 8.5 9 4 Conclusion: This table comprehensively demonstrates the differences between the Examples and the Comparative Examples in multiple key performance indicators. Examples 1-3 significantly outperformed the Comparative Examples in terms of fertilizer utilization, crop yield increase, soil water retention, and organic matter improvement. They also significantly outperformed the Comparative Examples in terms of stress resistance, fully demonstrating the technical advantages of the water-soluble fertilizers of the present invention.

[0040] The cost-effectiveness comparison of the embodiment and the comparative example is shown in the following table: Table 2 project Example 1 Example 2 Example 3 Comparative Example Fertilization cost per unit area (yuan / mu) 80 85 90 60 Average income increase per mu (yuan) 300 380 450 120 Input-output ratio 1:3.75 1:4.47 1:5 1:2 Conclusion: This table compares cost and benefit data. Although the fertilization cost of the embodiment is slightly higher than that of the comparative example, the per-mu income increase is significant, and the input-output ratio far exceeds that of the comparative example. This shows that although the water-soluble fertilizer of the present invention has a slightly higher initial cost, it can bring higher economic benefits and greater market value.

[0041] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing an organic water-soluble fertilizer containing polyamino acid, characterized in that: The preparation steps are as follows: S1. Raw material preparation: Prepare, by weight percentage, 15%-25% of polyamino acid, 10%-18% of modified potassium fulvic acid, 8%-15% of nano-scale trace element chelate, 5%-12% of a novel plant growth regulating complex composed of a γ-aminobutyric acid-salicylic acid conjugate and a chitosan oligosaccharide-brassinolide complex in a mass ratio of 1:1 to 2:1, 3%-8% of an acrylamide-acrylic acid-nano-montmorillonite graft copolymer water retaining agent, 2%-5% of a bioactive enzyme complex, and the balance water; the synthetic reaction formula for the γ-aminobutyric acid-salicylic acid conjugate is: ； The bioactive enzyme complex is composed of a urease inhibitor, a phosphatase activator and a cellulase in a mass ratio of (1-1.5):(0.8-1.2):(0.5-1); S2, potassium fulvic acid modification: add modified potassium fulvic acid into a reactor, heat it to 50-60°C, add nano-titanium dioxide and carbon nanotubes modified with potassium fulvic acid, stir and react for 1-2 hours to obtain a modified product; S3, chelate preparation: nano-scale trace element chelate raw materials are mixed in proportion, deionized water is added to prepare a solution with a concentration of 100-200 g / L, and a novel surfactant is added to form a nano-scale trace element chelate solution, wherein the novel surfactant is a mixture of alkyl glycoside and Tween-80 in a mass ratio of 2:1; S4, complex synthesis: prepare γ-aminobutyric acid-salicylic acid conjugate and chitosan oligosaccharide-brassinolide complex respectively, mix them at a mass ratio of 1-2:1, add the bioactive enzyme complex, and mix well; S5, mixing and preparation: add the remaining water to the reactor, and add the chitosan oligosaccharide-brassinolide complex, nano-scale trace element chelate solution, γ-aminobutyric acid-salicylic acid conjugate and chitosan oligosaccharide-brassinolide complex, polyamino acid, water retaining agent in sequence, add preservatives, mix well, and filter through a 1-5 μm precision filter.

2. The preparation process of a polyurethane-containing organic water-soluble fertilizer according to claim 1, wherein It also includes that the polyamino acid is prepared by a microbial fermentation method, the fermentation strain is a mixture of Bacillus and Lactobacillus in a volume ratio of 1-2:1, the fermentation temperature is 30-35°C, the fermentation time is 3-5 days, and the average molecular weight of the polyamino acid is 5000-10000Da, which is determined by gel permeation chromatography.

3. The preparation process of a polyurethane-containing organic water-soluble fertilizer according to claim 1, wherein The modified potassium fulvic acid is prepared by reacting potassium fulvic acid with a 10%-20% by mass ferrous sulfate solution and a 5%-10% by mass hydrogen peroxide solution at 60-70° C. for 1-2 hours, and nitrogen is introduced for protection during the reaction.

4. The preparation process of a polyurethane-containing organic water-soluble fertilizer according to claim 1, wherein In the acrylamide-acrylic acid-nano-montmorillonite graft copolymer water-retaining agent, the mass ratio of acrylamide, acrylic acid and nano-montmorillonite is 3-5:2-4:1-2, the graft reaction initiator is an ammonium persulfate-sodium bisulfite redox system, and the initiator dosage is 0.5%-1% of the total monomer mass.

5. The preparation process of a polyurethane-containing organic water-soluble fertilizer according to claim 1, wherein In the chitosan oligosaccharide-brassinolide complex, the chitosan oligosaccharide has a deacetylation degree of 80%-90%, a polymerization degree of 5-10, a reaction solvent of dimethyl sulfoxide, a reaction temperature of 25-30° C., and a reaction time of 6-8 hours.

6. The preparation process of a polyurethane-containing organic water-soluble fertilizer according to claim 1, wherein: The nano titanium dioxide has a particle size of 20-50 nm and its surface is double-layer modified with silane coupling agent KH570 and polydopamine; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-30 nm and a length of 1-10 μm and are carboxylated.

7. The preparation process of a polyurethane-containing organic water-soluble fertilizer according to claim 1, wherein: Also includes the following equipment and operations: A high-precision electronic scale is used to weigh the raw materials, with an error controlled within ±0.1%. The weighing of the bioactive enzyme complex must be carried out in a low-temperature environment. A reactor equipped with a temperature control device, a stirrer, and a nitrogen inlet device is used for potassium fulvate modification. The temperature control accuracy is ±1°C, the stirring speed can be adjusted within the range of 50-300 rpm, and the nitrogen inlet rate is 0.5-1 L / min. The chelate preparation was performed using a pH meter, a constant temperature water bath, and an ultrasonic oscillator. The pH meter had an accuracy of ±0.01, the constant temperature water bath had a temperature control accuracy of ±0.5°C, the ultrasonic oscillator had a power of 200-300W, and a frequency of 20-40kHz. A magnetic stirrer and a low temperature circulation device were used for complex synthesis. The stirring speed was stabilized at 100-200 r / min, and the low temperature circulation device controlled the temperature at 30-40°C with a fluctuation range of ±0.5°C. A mixing reactor equipped with a multi-stage stirring paddle, an online viscometer and a preservative adding device is used for mixing and preparation. The stirring paddle speed can be adjusted in stages, the online viscometer monitors the viscosity in real time, the preservative adding device can accurately control the addition amount, and is equipped with a 1-5μm precision filter for filtration.

8. The process for preparing a polyurethane-containing water-soluble organic fertilizer according to claim 7, wherein: The material of the reactor is stainless steel 316L lined with polytetrafluoroethylene to prevent material corrosion, and the inner wall of the reactor is polished with a roughness Ra≤0.8μm.

9. The process for preparing a polyurethane-containing water-soluble organic fertilizer according to claim 7, wherein: The precision filter adopts a cross-flow filtration method, the filtration pressure is controlled at 0.1-0.3MPa, and the filtration flux is 5-10L / (m²・h・MPa).

10. The process for preparing a polyurethane-containing water-soluble organic fertilizer according to claim 7, wherein: After the mixing is completed, the content of effective ingredients in the water-soluble fertilizer is quickly tested using a UV-visible spectrophotometer.

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