Specialized fertilizer for artemisia argyi and preparation method thereof

Abstract

This application relates to the field of compound fertilizer technology, specifically disclosing a special fertilizer for Artemisia argyi and its preparation method. This special fertilizer comprises the following components: 500-600 parts of well-rotted straw organic fertilizer, 60-100 parts of humic acid, 30-50 parts of amino acid raw powder, 40-50 parts of ammonium sulfate, 80-90 parts of monoammonium phosphate, 60-65 parts of potassium sulfate, 10-20 parts of calcium carbonate, 10-15 parts of magnesium sulfate, 1-3 parts of boric acid, 1-5 parts of ferrous sulfate, 1-5 parts of manganese sulfate, and 30-35 parts of bio-based polyurethane. The bio-based polyurethane coating agent uses bio-based PDI and castor oil-based polyols as raw materials, and employs chain extenders and grafting monomers derived from bio-based sources. This coated fertilizer effectively solves the problems of easy clumping and inconvenient storage, while also achieving precise nutrient supply through a slight slow-release effect. Meanwhile, the bio-based coating is biodegradable, leaves no soil residue, does not damage the soil structure, does not affect the medicinal quality of Artemisia argyi, and can also improve the utilization rate of fertilizer nutrients and reduce nutrient loss.

Description

Technical Field

[0001] This application relates to the field of compound fertilizer technology, specifically to a special fertilizer for Artemisia argyi and its preparation method. Background Technology

[0002] Organic-inorganic compound fertilizer is a new type of fertilizer made by scientifically blending well-rotted livestock and poultry manure, crop straw and other organic materials with inorganic fertilizers such as nitrogen, phosphorus and potassium. It combines the advantages of both organic and inorganic fertilizers, achieving a complementary effect of rapid and long-lasting results. It can quickly provide crops with the macronutrients needed for growth through inorganic nutrients, meeting the nutrient requirements of crops in the early stage of rapid growth. At the same time, it can continuously improve soil structure, enhance soil water and fertilizer retention and microbial activity through organic matter, activate nutrients fixed in the soil, and balance the supplementation of micronutrients. It can significantly improve fertilizer utilization and reduce nutrient loss, which can help increase the yield and quality of grains, fruits and vegetables, and alleviate problems such as soil compaction and acidification. It is suitable for planting various farmlands and cash crops.

[0003] Compound fertilizers are prone to absorbing moisture and clumping because their raw materials contain a variety of nutrients that are highly hygroscopic. If the granules are not dense enough during production, have a porous surface, and many sharp edges, the contact area with air will be greatly increased. The trace amounts of salt dissolved and released from the surface of the fertilizer granules will still crystallize to form "salt bridges" after drying, causing the granules to stick together. In addition, incomplete drying during production can leave residual free moisture. During storage and transportation, they are easily affected by high humidity, temperature fluctuations, and compression.

[0004] Once compound fertilizer absorbs moisture and clumps together, it will not only cause the fertilizer granules to stick together and become severely pulverized, greatly reducing the uniformity and flowability of the granules and affecting the normal operation of mechanized fertilization, but it will also cause uneven nutrient distribution and disordered release rhythm, reducing fertilizer utilization and actual application effect. At the same time, it will increase the difficulty of storage and transportation, affecting the commerciality and safety of fertilizer use.

[0005] In the production of compound fertilizers, the problems of moisture absorption and clumping can be improved by adding various functional additives and fillers or by coating the fertilizer. However, additives have defects such as poor uniformity and long-term effectiveness, while coatings have problems such as difficulty in degradation and slow nutrient release.

[0006] Therefore, the key is to ensure that compound fertilizers do not clump or absorb moisture while maintaining their performance and the soil environment. Summary of the Invention

[0007] To address the issues of moisture absorption and clumping in compound fertilizers, this application provides a bio-based coated compound fertilizer specifically for Artemisia argyi and its preparation method.

[0008] Using polymers such as polyurethane to coat compound fertilizers can not only effectively prevent the fertilizer from absorbing moisture and clumping, but also has good adhesion and thus good long-lasting effect. However, its degradation cycle is long and will have a negative impact on the soil environment.

[0009] This invention utilizes various bio-based components to prepare the bio-based polyurethane, which is then used to coat compound fertilizers. The raw materials, such as castor oil-based polyol and 1,5-pentanediisocyanate (PDI), are derived from natural components, exhibiting high degradability and preventing soil pollution. After polymerizing the castor oil-based polyol and 1,5-pentanediisocyanate, chain extension and grafting are performed. Lauryl amide diethanol with hydrophobic alkyl chains is used for chain extension, which improves the premature nutrient release and hydrolysis intolerance caused by the hydrophilicity and porosity of castor oil-based polyol. The grafting of modified monomers and the reaction with isocyanate increase the crosslinking density, making the membrane more flexible. This prevents rapid rupture leading to premature nutrient release and also avoids long-term insolubility causing nutrient depletion. Coating the compound fertilizer achieves a more gradual and sustained release of nutrients, making it suitable for Artemisia argyi cultivation. Furthermore, the process is simple and cost-effective.

[0010] This invention utilizes well-rotted organic fertilizer to provide abundant organic matter, improve soil structure, promote the development of Artemisia argyi roots, and enhance the soil's water and fertilizer retention capacity. Simultaneously, it avoids the damage to the soil caused by chemical fertilizers. Humic acid chelates nutrients in the soil, promoting the absorption of nitrogen, phosphorus, potassium, and trace elements by Artemisia argyi, reducing nutrient loss, and enhancing the stress resistance and quality of Artemisia argyi. Amino acid powder supplements the amino acids needed for Artemisia argyi growth, promotes thicker leaves, increases the fluffing rate, and forms a synergistic effect with grafted monomers, further enhancing the growth vigor and medicinal component content of Artemisia argyi.

[0011] Ammonium sulfate, monoammonium phosphate, and potassium sulfate provide the core nitrogen, phosphorus, and potassium nutrients needed for the growth of Artemisia argyi. Nitrogen promotes the growth of stems and leaves, phosphorus promotes the growth of roots, and potassium enhances the stress resistance and quality of Artemisia argyi. The sulfur-based formula is chlorine-free, which avoids burning the roots of Artemisia argyi, while supplementing sulfur to promote the synthesis of medicinal components in Artemisia argyi.

[0012] Calcium carbonate and magnesium sulfate supplement calcium and magnesium. Calcium prevents yellowing of mugwort leaves and brittle stems, while magnesium promotes chlorophyll synthesis and improves photosynthetic efficiency. Boric acid, ferrous sulfate, and manganese sulfate supplement boron, iron, and manganese. Boron promotes flowering and increases fluff production, iron prevents iron deficiency chlorosis, and manganese promotes nutrient absorption, synergistically improving mugwort yield and quality and preventing poor growth caused by micronutrient deficiencies.

[0013] In a first aspect, the present invention provides a special fertilizer for Artemisia argyi, comprising the following components: 500-600 parts of decomposed straw organic fertilizer, 60-100 parts of humic acid, 30-50 parts of amino acid raw powder, 40-50 parts of ammonium sulfate, 80-90 parts of monoammonium phosphate, 60-65 parts of potassium sulfate, 10-20 parts of calcium carbonate, 10-15 parts of magnesium sulfate, 1-3 parts of boric acid, 1-5 parts of ferrous sulfate, 1-5 parts of manganese sulfate, and 30-35 parts of bio-based polyurethane. The preparation method of the bio-based polyurethane includes the following steps: The catalyst was added to the castor oil-based polyol at 60-65℃ and stirred until homogeneous. Then, 1,5-pentanediisocyanate was added dropwise and stirred for 1-2 hours for polymerization. Lauroamide diethanol was added and stirred for 20-30 minutes for chain extension. The modified monomer was then added in 3 portions, and stirred until homogeneous after each addition. After all the monomers were added, the mixture was stirred for 1-2 hours and cooled to room temperature to obtain the bio-based polyurethane.

[0014] Furthermore, the catalyst is dibutyltin dilaurate.

[0015] Furthermore, the mass ratio of the castor oil-based polyol to 1,5-pentanediisocyanate, catalyst, lauramide diethanol, and modified monomer is 65:25-35:0.5-1:18-22:4-6.

[0016] Furthermore, the modified monomer is N-acetyl-serine.

[0017] Secondly, the present invention provides a method for preparing a special fertilizer for Artemisia argyi, comprising the following steps: The straw-derived organic fertilizer, humic acid, and amino acid powder are mixed evenly, crushed, and sieved. Then, they are mixed evenly with crushed and sieved ammonium sulfate, monoammonium phosphate, and potassium sulfate. Calcium carbonate, magnesium sulfate, boric acid, ferrous sulfate, and manganese sulfate are added and mixed evenly to obtain a compound fertilizer. The fertilizer is dried, and bio-based polyurethane is diluted with ethyl acetate to obtain a coating solution. The compound fertilizer is then sprayed with the solution. After spraying, the solution is cured, dried, and sieved to obtain a special fertilizer for Artemisia argyi.

[0018] Furthermore, the particle size of the sieved material is 100-200 mesh.

[0019] Furthermore, the drying temperature is 55-65℃.

[0020] Furthermore, the moisture content after drying must be ≤0.2%.

[0021] Furthermore, the spray rate is 5-6 mL / min.

[0022] Furthermore, the curing and drying process involves drying at 50-60°C for 10-30 minutes.

[0023] Compared with the prior art, the beneficial effects of this application are at least as follows: 1. This special fertilizer for Artemisia argyi provides abundant organic matter and improves soil structure through well-rotted organic fertilizer. Humic acid chelates nutrients, promotes absorption, and enhances the stress resistance of Artemisia argyi. Amino acid powder supplements nutrition, increases the yield of Artemisia argyi and the content of medicinal components. Ammonium sulfate, monoammonium phosphate, and potassium sulfate provide core nutrients to promote stem and leaf growth and strong root system. Trace elements such as calcium, magnesium, boron, iron, and manganese supplement the growth needs, prevent yellowing, enhance photosynthesis and stress resistance, and achieve multiple effects such as promoting growth, improving quality, and improving soil.

[0024] 2. The bio-based polyurethane coating agent prepared in this scheme uses bio-based PDI and castor oil-based polyol as raw materials, and adopts chain extenders and grafting monomers derived from bio-based materials to extend and graft the coating. The coating layer is not only flexible and dense, but also effectively prevents fertilizer from clumping, provides slight slow release, reduces nutrient loss, and prolongs fertilizer effect.

[0025] 3. The Artemisia argyi-specific fertilizer, treated with bio-based polyurethane coating, has a tightly bonded coating layer with the compound fertilizer, effectively solving the problems of clumping and inconvenient storage. It also achieves precise nutrient delivery through a slight slow-release effect, preventing root burn from excessive nutrient intake in the early stages and poor growth due to nutrient deficiency in the later stages, thus meeting the nutrient requirements of Artemisia argyi at each growth stage. Furthermore, the bio-based coating is biodegradable, leaves no soil residue, does not damage soil structure, does not affect the medicinal quality of Artemisia argyi, and improves nutrient utilization while reducing nutrient loss. In addition, the storage stability of the coated fertilizer is significantly improved, simultaneously meeting the requirements of being environmentally friendly, practical, and compatible with various plant species. Detailed Implementation

[0026] The various embodiments or implementation schemes in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments.

[0027] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] In this specification, unless otherwise specified, "parts" refers to "parts by weight".

[0030] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0031] Decomposed straw organic fertilizer with an organic matter content of ≥45% and a particle size of 100 mesh; Humic acid, purity ≥70%, water solubility ≥80%, pH value 5.5-7.0; Amino acid raw powder, with a total amino acid content of ≥90%; Castor oil-based polyols, hydroxyl value 180-220 mg KOH / g; 1,5-Pentanediisocyanate, CAS No.: 4538-42-5; Laurylamide diethanol, CAS No.: 120-40-1; N-acetyl-serine, CAS No.: 97-14-3.

[0032] Example 1 A method for preparing a special fertilizer for Artemisia argyi includes the following steps: Mix 550 parts of decomposed straw organic fertilizer, 80 parts of humic acid, and 40 parts of amino acid raw powder evenly, crush them, and pass them through a 200-mesh sieve. Then mix them evenly with 48 parts of ammonium sulfate, 87 parts of monoammonium phosphate, and 62 parts of potassium sulfate that have been crushed through a 200-mesh sieve. Continue to add 15 parts of calcium carbonate, 12 parts of magnesium sulfate, 2 parts of boric acid, 3 parts of ferrous sulfate, and 3 parts of manganese sulfate and mix evenly to obtain a compound fertilizer. Dry it at 60℃ until the moisture content is ≤0.2%. Dilute 32 parts of bio-based polyurethane with 10 parts of ethyl acetate to a viscosity of <350mPa·s to obtain a coating solution. Spray the compound fertilizer with a spraying rate of 5mL / min. After spraying, cure and dry it at 50℃ for 20min and pass it through a 100-mesh sieve to obtain Qi Ai special fertilizer. The preparation method of the bio-based polyurethane includes the following steps: At 65°C, 0.8 parts of dibutyltin dilaurate were added to 65 parts of castor oil-based polyol and stirred until homogeneous. Then, 29 parts of 1,5-pentanediisocyanate were added dropwise and stirred for 1 hour to polymerize. 20 parts of lauramide diethanol were added and stirred for 25 minutes to extend the chain. Then, 5 parts of N-acetyl-serine were added in 3 portions and stirred until homogeneous after each addition. After all the additions were completed, the mixture was stirred for 1 hour and cooled to room temperature to obtain bio-based polyurethane.

[0033] Example 2 It is basically the same as Example 1, except that the amount of N-acetyl-serine is 4 parts.

[0034] Example 3 It is basically the same as Example 1, except that the amount of N-acetyl-serine is 6 parts.

[0035] Comparative Example 1 A method for preparing a special fertilizer for Artemisia argyi includes the following steps: Mix 550 parts of decomposed straw organic fertilizer, 80 parts of humic acid, and 40 parts of amino acid raw powder evenly, crush them, and pass them through a 200-mesh sieve. Then mix them evenly with 48 parts of ammonium sulfate, 87 parts of monoammonium phosphate, and 62 parts of potassium sulfate that have been crushed through a 200-mesh sieve. Continue to add 15 parts of calcium carbonate, 12 parts of magnesium sulfate, 2 parts of boric acid, 3 parts of ferrous sulfate, and 3 parts of manganese sulfate and mix evenly to obtain compound fertilizer. Dry it at 60℃ until the moisture content is ≤0.2% and then pass it through a 100-mesh sieve to obtain Qi Ai special fertilizer.

[0036] Comparative Example 2 A method for preparing a special fertilizer for Artemisia argyi includes the following steps: Mix 550 parts of decomposed straw organic fertilizer, 80 parts of humic acid, and 40 parts of amino acid raw powder evenly, crush them, and pass them through a 200-mesh sieve. Then mix them evenly with 48 parts of ammonium sulfate, 87 parts of monoammonium phosphate, and 62 parts of potassium sulfate that have been crushed through a 200-mesh sieve. Continue to add 15 parts of calcium carbonate, 12 parts of magnesium sulfate, 2 parts of boric acid, 3 parts of ferrous sulfate, and 3 parts of manganese sulfate and mix evenly to obtain a compound fertilizer. Dry it at 60℃ until the moisture content is ≤0.2%. Dilute 32 parts of bio-based polyurethane with 10 parts of ethyl acetate to a viscosity of <350mPa·s to obtain a coating solution. Spray the compound fertilizer with a spraying rate of 5mL / min. After spraying, cure and dry it at 50℃ for 20min and pass it through a 100-mesh sieve to obtain Qi Ai special fertilizer. The preparation method of the bio-based polyurethane includes the following steps: At 65°C, 0.8 parts of dibutyltin dilaurate were added to 65 parts of castor oil-based polyol, stirred evenly, and then 29 parts of 1,5-pentanediisocyanate were added dropwise. The mixture was stirred for 1 hour to carry out polymerization. Then, 20 parts of lauramide diethanol were added and stirred for 25 minutes to carry out chain extension. The mixture was cooled to room temperature to obtain bio-based polyurethane.

[0037] Comparative Example 3 It is basically the same as Example 1, except that N-acetyl-serine is replaced with an equimolar amount of glycine.

[0038] Comparative Example 4 It is basically the same as Example 1, except that lauramide diethanol is replaced with an equimolar amount of 1,4-butanediol.

[0039] Test section 1. Field planting trials were conducted on the Artemisia argyi-specific fertilizers prepared in the examples and comparative examples. The main local Artemisia argyi variety was selected, and the planting soil was sandy loam with a neutral pH. A randomized block design was used, with 4 replicates per treatment and a cell size of 10m². 2 All field management practices (watering, weeding, and pest and disease control) are completely consistent across all plots. Before planting, prepare the land, select healthy Artemisia seeds for seedling cultivation, and propagate using rhizomes. Planting should take place in late March (average daily temperature ≥15℃), with a spacing of 20cm × 30cm and a planting depth of 5-6cm. Water thoroughly immediately after planting. Transplant seedlings when they reach 5cm in height. Before transplanting, apply Artemisia-specific fertilizer as base fertilizer to the soil at a rate of 50kg / mu. Top-dressing should be applied one month and two months later at a rate of 30kg / mu. Regular irrigation, weeding, and pest and disease control are maintained from planting to harvest, with all plots using the same control measures. Harvesting was carried out uniformly during the peak leafing stage of Artemisia argyi (90 days after planting). The plants were cut 5cm above the ground. Twenty plants were randomly selected from each plot to measure growth traits, and the remaining plants were all harvested to determine yield. Plant height was measured using a measuring tape from the base to the top of the plant. Stem diameter was measured using calipers at half the stem height. After harvesting, the plants were air-dried and the dry weight of the leaves was measured to calculate the leaf yield per hectare.

[0040] 2. The fertilizer release of the Artemisia argyi-specific fertilizer prepared in the examples and comparative examples was tested. 10.0 g of fertilizer sample was taken, 200 mL of water was added, and the sample was sealed. Five micropores were punched at the bottle mouth for ventilation, and the sample was placed at room temperature (25℃) to stand. Samples were taken at different times, with 5 mL of extract taken each time. After centrifugation and filtration, the nitrogen concentration in the filtrate was determined using the Kjeldahl method, and the cumulative nutrient release rate was calculated. The number of days when the cumulative release rate reached 80% was defined as the cumulative nutrient release period. Three parallel experiments were conducted for each sample group, and the average value was taken as the final result.

[0041] 3. The agglomeration rate of the Artemisia argyi-specific fertilizer prepared in the examples and comparative examples was tested. 50.0 g (m1) of uniform sample was weighed, with three parallel tests per group. The sample was spread evenly in a petri dish to a thickness of approximately 1 cm, without compression or compaction. The petri dish was placed in a constant temperature and humidity chamber, set at 30℃ and 85% relative humidity, and left to stand for 15 days to simulate a high-humidity storage environment. After 15 days, the sample was removed without applying any external force or crushing and transferred to a 100-mesh sieve to allow loose, qualified particles to pass through. The agglomerated material that did not pass through the sieve was collected, and its mass was weighed (recorded as m2). The agglomeration rate (%) was calculated as (m2 / m1) × 100%, and the average of the three parallel tests was taken as the final result.

[0042] Table 1

[0043] Table 2

[0044] As shown in Tables 1 and 2, the Artemisia argyi-specific fertilizer prepared in this invention can improve the quality of Artemisia argyi, resulting in good growth and high yield. This is attributed to the rich organic matter provided by the well-rotted organic fertilizer, which improves soil structure; the humic acid chelates nutrients, promotes absorption, and enhances the stress resistance of Artemisia argyi; the amino acid powder supplements nutrition and increases the yield of Artemisia argyi fluff; ammonium sulfate, monoammonium phosphate, and potassium sulfate provide core nutrients to promote stem and leaf growth and robust root system; and trace elements such as calcium, magnesium, boron, iron, and manganese supplement the growth needs, prevent yellowing, and enhance photosynthesis and stress resistance. Furthermore, the Artemisia argyi-specific fertilizer treated with bio-based polyurethane coating has a tightly bonded coating layer with the compound fertilizer body, effectively solving the problems of easy clumping and inconvenient storage. It also achieves precise nutrient supply through a slight slow-release effect, avoiding excessive nutrient exposure that burns the roots in the early stages and nutrient deficiency that leads to poor growth in the later stages, thus meeting the nutrient requirements of Artemisia argyi at each growth stage. Meanwhile, the bio-based coating is biodegradable, leaves no soil residue, does not damage the soil structure, does not affect the medicinal quality of Artemisia argyi, and can also improve the utilization rate of fertilizer nutrients and reduce nutrient loss.

[0045] Compared to Comparative Examples 1-4, Example 1 showed significantly better quality and yield of Artemisia argyi. This was mainly because the compound fertilizer in Comparative Example 1 was not coated, resulting in severe caking and instant nutrient release, leading to the worst growth of Artemisia argyi. While Comparative Example 2 used polyurethane modification, it did not employ modified monomer grafting, resulting in weaker interactions between molecular chains. The membrane structure was likely uneven, non-dense, and even contained microscopic defects. This imperfect membrane tended to form an incomplete barrier, causing nutrients to be released primarily through these defects after moisture wetting, failing to create uniform and controllable nutrient release channels. This resulted in slow fertilizer release and insufficient fertilizer efficiency, thus affecting caking and the growth of Artemisia argyi. Comparative Example 4 used 1,4-butanediol as a chain extender, which, compared to laurylamide diethanol, lacked hydrophobicity. This caused the membrane to easily swell and break, leading to premature nutrient release and nutrient deficiency in the later stages of growth, thus reducing quality.

[0046] Compared to Comparative Example 3, Example 1 uses glycine, also a bio-based component, for graft modification. However, the primary amino group in glycine reacts extremely strongly with isocyanate, resulting in a significantly increased grafting density. This leads to localized overpolymerization and larger membrane pores, resulting in faster fertilizer release and a greater tendency for caking in Comparative Example 3. N-acetyl-serine, as a modifying monomer, has a much lower amino group activity in its amide group than the primary amino group in glycine. Therefore, in the grafting reaction, N-acetyl-serine crosslinks through the hydroxyl groups of its side chains, increasing the crosslinking density of the entire polyurethane network structure without initiating overpolymerization. This makes the polymer network structure of Example 1 more uniform and ordered, without generating excessively large pores.

[0047] Compared with Examples 2 and 3, the amount of modifier used in Example 1 is different, which leads to different grafting densities. In terms of effect, the amount used in Example 1 is the best. This indicates that when the grafting density is low, the membrane layer has more pores, while when the grafting density is high, the membrane layer is thicker and the pores are too dense. These factors affect water absorption and fertilizer release, thus affecting the growth of Artemisia argyi.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A fertilizer specifically for Artemisia argyi, characterized in that, It includes the following components: 500-600 parts of decomposed straw organic fertilizer, 60-100 parts of humic acid, 30-50 parts of amino acid raw powder, 40-50 parts of ammonium sulfate, 80-90 parts of monoammonium phosphate, 60-65 parts of potassium sulfate, 10-20 parts of calcium carbonate, 10-15 parts of magnesium sulfate, 1-3 parts of boric acid, 1-5 parts of ferrous sulfate, 1-5 parts of manganese sulfate, and 30-35 parts of bio-based polyurethane. The preparation method of the bio-based polyurethane includes the following steps: The catalyst was added to the castor oil-based polyol at 60-65℃ and stirred until homogeneous. Then, 1,5-pentanediisocyanate was added dropwise and stirred for 1-2 hours for polymerization. Lauroamide diethanol was added and stirred for 20-30 minutes for chain extension. The modified monomer was then added in 3 portions, and stirred until homogeneous after each addition. After all the monomers were added, the mixture was stirred for 1-2 hours and cooled to room temperature to obtain the bio-based polyurethane.

2. The special fertilizer for Artemisia argyi as described in claim 1, characterized in that, It includes the following components, wherein the catalyst is dibutyltin dilaurate.

3. The special fertilizer for Artemisia argyi as described in claim 1, characterized in that, The mass ratio of the castor oil-based polyol to 1,5-pentanediisocyanate, catalyst, lauramide diethanol, and modified monomer is 65:25-35:0.5-1:18-22:4-6.

4. The special fertilizer for Artemisia argyi as described in claim 1, characterized in that, The modified monomer is N-acetyl-serine.

5. The method for preparing the Artemisia argyi-specific fertilizer according to any one of claims 1-4, characterized in that, Includes the following steps: The straw-derived organic fertilizer, humic acid, and amino acid powder are mixed evenly, crushed, and sieved. Then, they are mixed evenly with crushed and sieved ammonium sulfate, monoammonium phosphate, and potassium sulfate. Calcium carbonate, magnesium sulfate, boric acid, ferrous sulfate, and manganese sulfate are added and mixed evenly to obtain a compound fertilizer. The fertilizer is dried, and bio-based polyurethane is diluted with ethyl acetate to obtain a coating solution. The compound fertilizer is then sprayed with the solution. After spraying, the solution is cured, dried, and sieved to obtain a special fertilizer for Artemisia argyi.

6. The method for preparing the Artemisia argyi-specific fertilizer as described in claim 5, characterized in that, The particle size of the sieved material is 100-200 mesh.

7. The method for preparing the Artemisia argyi-specific fertilizer as described in claim 5, characterized in that, The drying temperature is 55-65℃.

8. The method for preparing the Artemisia argyi-specific fertilizer as described in claim 7, characterized in that, The moisture content after drying must be ≤0.2%.

9. The method for preparing the Artemisia argyi-specific fertilizer as described in claim 7, characterized in that, The spray rate is 5-6 mL / min.

10. The method for preparing the Artemisia argyi-specific fertilizer as described in claim 7, characterized in that, The curing and drying process involves drying at 50-60℃ for 10-30 minutes.

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