A fertilizer synergist, a preparation method thereof and a synergistic fertilizer

Abstract

The application provides a kind of fertilizer synergist and its preparation method, synergic fertilizer, the fertilizer synergist includes the following weight parts of raw materials: N-acetyl glucosamine 20-50 parts, nutrient enhancer 10-30 parts, structure stabilizer 1-15 parts, auxiliary agent 5-20 parts;The nutrient enhancer is organic acid and its derivative with two or more than two carboxyl or phosphoric acid group, organic acid and its derivative with carboxyl and phosphoric acid group simultaneously.The fertilizer synergist of the application can be added to synergic fertilizer, and has good compatibility with fertilizer, high stability, can effectively improve plant nutrient utilization, promote plant growth, and enhance plant stress resistance.

Description

Technical Field

[0001] This invention relates to the field of fertilizer technology, and in particular to a fertilizer enhancer, its preparation method, and an enhanced fertilizer. Background Technology

[0002] The long-term and excessive use of traditional chemical fertilizers has triggered a series of severe ecological and environmental problems and agricultural production challenges. Among these, the most prominent issues are: First, the average utilization rate of major nutrients such as nitrogen, phosphorus, and potassium is low, with large amounts lost through leaching and volatilization, resulting not only in resource waste and economic losses but also environmental pressures such as eutrophication of water bodies and greenhouse gas emissions. Second, over-reliance on chemical nutrient input easily leads to soil compaction, acidification, decline in organic matter, and imbalance of beneficial microbial communities, seriously threatening soil health and sustainable productivity. Furthermore, under continuous cropping and single-nutrient management models, the inherent resilience (disease resistance, drought resistance, and salt tolerance) of crops is often weakened, further increasing dependence on pesticides and irrigation, creating a vicious cycle.

[0003] Therefore, developing green, efficient, and environmentally friendly new fertilizers and synergistic technologies has become a cutting-edge direction in global agricultural science and technology. Current research and industrial practice mainly focus on two paths: one is to develop new slow-release fertilizers, which delay nutrient release through physical encapsulation or chemical binding to improve utilization; the other is to add various functional adjuvants to fertilizers, aiming to achieve synergistic effects, improve soil, and stimulate plant potential through biological or chemical means. Among the many functional adjuvants, bio-derived natural products are widely favored due to their good environmental compatibility, high biosafety, and often multiple physiological activities.

[0004] N-acetylglucosamine is a naturally occurring amino monosaccharide. Traditionally, it has been extracted primarily through a strong acid-base chemical process using the shells of crustaceans. This process suffers from environmental pollution, numerous impurities in the product, and the potential for allergen residues, limiting its application in high-end green agriculture. In contrast, N-acetylglucosamine prepared using microbial fermentation offers significant green advantages.

[0005] However, the direct application of N-acetylglucosamine in agriculture, especially as a fertilizer additive, still faces significant technical bottlenecks and limitations: First, its function is singular and unstable. A single N-acetylglucosamine molecule is easily and rapidly degraded by microorganisms in complex soil-crop systems, and its induction signals and growth-promoting effects are often short-lived and unpredictable. Second, it has poor compatibility with fertilizer systems. Its strong hydrophilicity does not match the physical properties of most fertilizer particles, making it difficult to maintain stable dispersion and uniform binding during mixing, granulation, and storage, which easily leads to separation and inactivation.

[0006] Therefore, developing a specialized fertilizer enhancer with N-acetylglucosamine as the core raw material, a clear process route, environmental friendliness, and the ability to effectively improve its stability, functionality, and compatibility is of great practical significance. Summary of the Invention

[0007] The purpose of this invention is to provide a fertilizer enhancer and its preparation method, as well as an enhanced fertilizer, to solve the technical problems of poor stability, poor compatibility with fertilizer systems, and difficulty in fully exerting the function of N-acetylglucosamine as a fertilizer additive in the prior art.

[0008] This invention provides the following technical solution: A fertilizer synergist comprises the following raw materials in parts by weight: 20-50 parts N-acetylglucosamine, 10-30 parts nutrient enhancer, 1-15 parts structure stabilizer, and 5-20 parts adjuvant. The nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups.

[0009] Preferably, the purity of the N-acetylglucosamine is ≥95%; Optionally, the N-acetylglucosamine is prepared by microbial fermentation.

[0010] The microbial fermentation described is a conventional technique in the field. N-acetylglucosamine is obtained through fermentation, extraction, purification, concentration, crystallization, and drying of raw materials. This invention can use hydrolyzed sugars from agricultural waste (such as corn cobs and sugarcane bagasse) as fermentation raw materials, ensuring a sustainable source that aligns with the development concepts of green chemistry and circular agriculture. The production process is characterized by mild conditions, avoiding the use of strong chemical reagents, resulting in a product with high purity and better biocompatibility. N-acetylglucosamine derived from microbial fermentation is suitable for use as a fertilizer synergist. It not only acts as a signaling molecule in plant physiological regulation and stimulates root development but also activates systemic resistance (ISR) in plants, enhancing their tolerance to biotic and abiotic stresses.

[0011] Preferably, the N-acetylglucosamine is obtained by the following method: using corn cob / sugarcane bagasse as raw material, using cellulase and hemicellulase to hydrolyze to obtain a mixed sugar mainly composed of glucose and xylose as fermentation raw material, using recombinant Escherichia coli for fermentation, and after centrifugation, impurity removal, decolorization, extraction, concentration, crystallization and drying, a finished product with a purity ≥98% can be obtained.

[0012] Preferably, the nutrient enhancer is one or more of citric acid, phytic acid, and their salts; Optionally, the structural stabilizer is one of tannic acid and genipin; Optionally, the adjuvant is one or more of lecithin, alkyl glycoside, and silicate.

[0013] This invention provides a method for preparing a fertilizer synergist, comprising the following steps: (1) Dissolve N-acetylglucosamine and nutrient enhancer in a solvent to obtain a premix; (2) Add a structure stabilizer to the premixed liquid obtained in step (1) and react to obtain the modified product; (3) Add the additive to the modified product obtained in step (2) and mix evenly to obtain the final product.

[0014] Preferably, in step (1), the solvent is one of water or an aqueous solution of a C1-C6 fatty alcohol; Optionally, the concentration of the N-acetylglucosamine in the solvent is 50-100 g / L; Optionally, the N-acetylglucosamine and the nutrient enhancer are dissolved in the solvent at a temperature of 30-50°C.

[0015] Preferably, in step (2), the reaction is carried out at a pH of 7.5-9.0 and a temperature of 50-70°C for 2-6 hours with stirring. Optionally, in step (2), the structure stabilizer is first dissolved in a solvent and then added dropwise to the premixed solution.

[0016] Optionally, in step (2), the structure stabilizer is added to the premixed solution slowly dropwise, and stirring is maintained during both the dropwise addition and the reaction. In this invention, as a specific embodiment, the structure stabilizer can be added to the premixed solution using a constant-pressure dropping funnel or a peristaltic pump to achieve slow dropwise addition. Both the dropwise addition and the reaction are carried out under continuous, gentle stirring, which avoids excessively high local concentrations that could lead to gelation.

[0017] Preferably, in step (3), homogenization is used to mix the modified product and the additive evenly.

[0018] Preferably, step (3) further includes a drying step; Optionally, the drying is spray drying; the inlet air temperature of the spray drying is 120-160℃, and the outlet air temperature is 70-90℃.

[0019] Optionally, a carrier may be added during spray drying to improve flowability, the carrier being selected from either porous starch or silica.

[0020] Preferably, step (3) further includes a concentration and granulation step; Optionally, the concentration and granulation process involves vacuum concentration followed by fluidized bed granulation.

[0021] Preferably, step (1) further includes a step of deacetylation of the N-acetylglucosamine.

[0022] The present invention also provides an enhanced fertilizer, comprising the aforementioned fertilizer enhancer.

[0023] The enhanced fertilizer, by adding the fertilizer enhancer to the base fertilizer and applying it to crops or crop soil, can significantly promote crop growth and enhance their disease resistance.

[0024] The basic fertilizer refers to a fertilizer containing one or more nutrients required for crop growth, produced by chemical and / or physical methods, including nitrogen, phosphorus, potassium, and other micronutrients such as magnesium, calcium, sodium, manganese, sulfur, boron, copper, iron, molybdenum, and zinc. The fertilizer synergist can be directly added to the basic fertilizer by dry mixing or melt blending, exhibiting good compatibility with the fertilizer system. In some embodiments, the amount of fertilizer synergist added to the synergistic fertilizer is 2wt‰-10wt‰ by weight percentage.

[0025] The above-described solution of the present invention has at least the following beneficial effects: A fertilizer enhancer comprises the following raw materials in parts by weight: 20-50 parts of N-acetylglucosamine, 10-30 parts of nutrient enhancer, 1-15 parts of structure stabilizer, and 5-20 parts of adjuvant; wherein the nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups.

[0026] The fertilizer synergist is first formed into a pre-assembly by deacetylated N-acetylglucosamine and the nutrient enhancer; then the pre-assembly is mixed with the structural stabilizer, causing the amino groups of the deacetylated N-acetylglucosamine to undergo a cross-linking reaction with the structural stabilizer, forming a network structure in which the nutrient enhancer and the cross-linking product are entangled or interpenetrating. This invention uses N-acetylglucosamine as the core raw material of the fertilizer synergist, and functionalizes the deacetylated N-acetylglucosamine through nutrient enhancers and structural stabilizers. This not only retains the original growth-promoting and resistance-inducing activities of N-acetylglucosamine, but also improves its compatibility and stability with the fertilizer system, and enhances its nutrient chelation and slow-release capabilities through the introduced functional groups.

[0027] The nutrient enhancer contains multiple carboxyl or phosphate groups. These carboxyl or phosphate groups form ion pairs with the amino group of deacetylated N-acetylglucosamine and hydrogen bond networks with its hydroxyl groups, enabling effective molecular recognition and self-assembly. This results in a clear, homogeneous, and thermodynamically stable premixed solution, providing a uniform molecular dispersion basis for subsequent cross-linking reactions with the structure stabilizer. Under alkaline conditions, the structure stabilizer covalently cross-links with the amino group of deacetylated N-acetylglucosamine and forms hydrogen bond networks with the amino and hydroxyl groups of deacetylated N-acetylglucosamine and the carboxyl or phosphate groups of the nutrient enhancer. The multiple carboxyl or phosphate groups of the nutrient enhancer form multiple anion binding sites in an alkaline environment, enabling simultaneous interaction with multiple positively charged or polar molecules. This effectively enriches and orients reactive groups, promoting the reaction between the preassembled component and the structure stabilizer, resulting in a dense and stable ternary complex of "deacetylated N-acetylglucosamine-nutrient enhancer-structure stabilizer". When the nutrient enhancer is one or more of citric acid, phytic acid and their salts, citric acid and phytic acid contain three or more carboxyl or phosphate groups. While forming a pre-assembled structure with the hydroxyl and amino groups of the deacetylated N-acetylglucosamine through electrostatic interactions and hydrogen bonds, it can also promote the approach of the deacetylated N-acetylglucosamine and the structural stabilizer in multiple directions through bridging effects, thereby improving reaction efficiency and enhancing the network uniformity of the reaction products. The three-dimensional molecular configuration of the nutrient enhancer gives the formed "deacetylated N-acetylglucosamine-nutrient enhancer-structural stabilizer" ternary complex higher network strength and stability.

[0028] The adjuvant is one or more of lecithin, alkyl glycosides, and silicates. Lecithin and alkyl glycosides are amphiphilic and can be adsorbed on the surface of the reaction product, reducing interfacial tension and preventing product particle aggregation. The layered silicate can swell in water to form a three-dimensional network, constructing a suspended skeleton. Through electrostatic repulsion and steric hindrance, it stabilizes the dispersion system, provides yield stress, and prevents particle sedimentation, thereby obtaining a long-term stable suspension, giving the fertilizer synergist excellent physical stability and compatibility.

[0029] The above-mentioned substances work together to help improve the problems of poor stability, poor compatibility with fertilizer systems, and difficulty in fully exerting their functions as fertilizer additives, so that the fertilizer synergist can have multiple functions such as improving nutrient utilization, enhancing stress resistance, and promoting plant growth. Attached Figure Description

[0030] Figure 1 A bar chart showing the growth promotion rate of each group in the effect experiment; Figure 2 This is a bar chart showing the antibacterial efficiency of each group in the efficacy experiment. Detailed Implementation

[0031] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available products; different manufacturers and models of raw materials do not affect the implementation of the technical solution or the achievement of the technical effect of this invention.

[0032] In the following embodiments, the CAS number of citric acid is 77-92-9, the CAS number of phytic acid is 83-86-3, the CAS number of genipin is 6902-77-8, the CAS number of tannic acid is 1401-55-4, the CAS number of lecithin is 8002-43-5, the CAS number of alkyl glycoside is 157707-88-5, the CAS number of magnesium aluminum silicate is 71205-22-6, the CAS number of malic acid is 6915-15-7, the CAS number of acetic acid is 367-64-6, and the CAS number of polyglutamic acid is 25513-46-6.

[0033] Example 1 The fertilizer synergist of this embodiment includes the following raw materials in parts by weight: 50 parts of N-acetylglucosamine, 30 parts of nutrient enhancer, 15 parts of structural stabilizer, and 12 parts of adjuvant. The nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups. In this embodiment, the nutrient enhancer is citric acid. The N-acetylglucosamine is prepared by microbial fermentation and has a purity ≥95%. The structural stabilizer is genipin. The adjuvants are lecithin and magnesium aluminum silicate, with a weight ratio of lecithin to magnesium aluminum silicate of 1:2.

[0034] The preparation method of the fertilizer synergist described in this embodiment includes the following steps: (1) At a temperature of 45°C, deacetylated N-acetylglucosamine and a nutrient enhancer were dissolved in a solvent to obtain a clear and transparent premixed solution; The solvent is water; the concentration of the deacetylated N-acetylglucosamine in the solvent is 100 g / L. The N-acetylglucosamine can be deacetylated using conventional methods of the prior art, as long as the acetyl group can be removed to obtain glucosamine (the same applies below, and will not be repeated hereafter).

[0035] (2) Dissolve the structure stabilizer in the solvent and add it dropwise to the premixed solution obtained in step (1). The dropwise addition is completed within 1 hour. Stirring is performed during the dropwise addition, and the pH value of the reaction system is maintained at 8.5 by adding 5wt% sodium bicarbonate aqueous solution. The reaction is stirred for 3 hours at a temperature of 65℃ to obtain the modified product. The solvent is a mixture of ethanol and water; the concentration of the structure stabilizer in the solvent is 60 g / L.

[0036] (3) Add the additive to the modified product obtained in step (2), and use a high-speed shear emulsifier to homogenize it at a speed of 10,000 rpm for 20 min to obtain a uniform, stable, slightly viscous light yellow suspension.

[0037] As a preferred implementation of this embodiment, it further includes adding fumed silica equivalent to 10% of its solid content to the suspension, mixing it evenly, and drying it to obtain a light yellow fine powder with good flowability.

[0038] The drying process is spray drying; the feed rate of the spray drying is 15 mL / min, the inlet air temperature is 145℃, and the outlet air temperature is 82℃.

[0039] The enhanced fertilizer described in this embodiment includes the fertilizer enhancer.

[0040] Example 2

[0041] The fertilizer synergist of this embodiment includes the following raw materials in parts by weight: 20 parts N-acetylglucosamine, 10 parts nutrient enhancer, 4 parts structural stabilizer, and 8 parts adjuvant. The nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups. In this embodiment, it is citrate. The N-acetylglucosamine is prepared by microbial fermentation and has a purity ≥95%. The structural stabilizer is tannic acid. The adjuvants are lecithin and magnesium aluminum silicate, with a weight ratio of 3:5.

[0042] The preparation method of the fertilizer synergist described in this embodiment includes the following steps: (1) At a temperature of 30°C, deacetylated N-acetylglucosamine and a nutrient enhancer were dissolved in a solvent to obtain a clear and transparent premixed solution; The solvent is water; the concentration of the deacetylated N-acetylglucosamine in the solvent is 60 g / L.

[0043] (2) Dissolve the structure stabilizer in the solvent and add it dropwise to the premixed solution obtained in step (1). The dropwise addition is completed within 1 hour. Stirring is carried out while adding the solution. The pH of the reaction system is maintained at 8.0 by adding 5wt% sodium bicarbonate aqueous solution. The reaction is carried out at 70℃ for 2 hours and the modified product is obtained. The solvent is a mixture of ethanol and water; the concentration of the structure stabilizer in the solvent is 60 g / L.

[0044] (3) Add the additive to the modified product obtained in step (2), and use a high-speed shear emulsifier to homogenize it at a speed of 10,000 rpm for 15 min to obtain a uniform, stable, slightly viscous light yellow suspension.

[0045] As a preferred implementation of this embodiment, a concentration and granulation step is also included; the concentration and granulation involves first vacuum concentration, and then fluidized bed granulation.

[0046] The enhanced fertilizer described in this embodiment includes the fertilizer enhancer.

[0047] Example 3 The fertilizer synergist of this embodiment includes the following raw materials in parts by weight: 40 parts N-acetylglucosamine, 20 parts nutrient enhancer, 10 parts structural stabilizer, and 20 parts adjuvant. The nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups. In this embodiment, the nutrient enhancer is phytic acid. The N-acetylglucosamine is prepared by microbial fermentation and has a purity ≥95%. The structure stabilizer is genipin. The adjuvants are alkyl glycosides and magnesium aluminum silicate, with a weight ratio of 2:3.

[0048] The preparation method of the fertilizer synergist described in this embodiment includes the following steps: (1) At a temperature of 50°C, deacetylated N-acetylglucosamine and a nutrient enhancer were dissolved in a solvent to obtain a clear and transparent premixed solution; The solvent is water; the concentration of the deacetylated N-acetylglucosamine in the solvent is 85 g / L.

[0049] (2) Dissolve the structure stabilizer in the solvent and add it dropwise to the premixed solution obtained in step (1). The dropwise addition is completed within 1 hour. Stirring is performed during the dropwise addition, and the pH value of the reaction system is maintained at 7.5 by adding 5wt% sodium bicarbonate aqueous solution. The reaction is carried out at 60℃ for 6 hours to obtain the modified product. The solvent is a mixture of ethanol and water; the concentration of the structure stabilizer in the solvent is 60 g / L.

[0050] (3) Add the additive to the modified product obtained in step (2), and use a high-speed shear emulsifier to homogenize it at a speed of 10,000 rpm for 30 min to obtain a uniform, stable, slightly viscous light yellow suspension.

[0051] As a preferred implementation of this embodiment, it further includes adding fumed silica equivalent to 10% of its solid content to the suspension, mixing it evenly, and drying it to obtain a light yellow fine powder with good flowability.

[0052] The drying process is spray drying; the feed rate of the spray drying is 15 mL / min, the inlet air temperature is 155℃, and the outlet air temperature is 85℃.

[0053] The enhanced fertilizer described in this embodiment includes the fertilizer enhancer.

[0054] Example 4 The fertilizer synergist of this embodiment includes the following raw materials in parts by weight: 30 parts N-acetylglucosamine, 12 parts nutrient enhancer, 6 parts structural stabilizer, and 10 parts adjuvant. The nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups. In this embodiment, the nutrient enhancer is a mixture of citric acid and phytic acid in a weight ratio of 1:5. The N-acetylglucosamine is prepared by microbial fermentation with a purity ≥95%. The structural stabilizer is tannic acid. The adjuvants are lecithin and magnesium aluminum silicate, with a weight ratio of lecithin to magnesium aluminum silicate of 2:3.

[0055] The preparation method of the fertilizer synergist described in this embodiment includes the following steps: (1) At a temperature of 45°C, deacetylated N-acetylglucosamine and a nutrient enhancer were dissolved in a solvent to obtain a clear and transparent premixed solution; The solvent is water; the concentration of the deacetylated N-acetylglucosamine in the solvent is 75 g / L.

[0056] (2) Dissolve the structure stabilizer in the solvent and add it dropwise to the premixed solution obtained in step (1). The dropwise addition is completed within 1 hour. Stirring is performed during the dropwise addition, and the pH value of the reaction system is maintained at 8.0 by adding 5wt% sodium bicarbonate aqueous solution. The reaction is stirred for 4 hours at a temperature of 65℃ to obtain the modified product. The solvent is a mixture of ethanol and water; the concentration of the structure stabilizer in the solvent is 60 g / L.

[0057] (3) Add the additive to the modified product obtained in step (2), and use a high-speed shear emulsifier to homogenize it at a speed of 10,000 rpm for 20 min to obtain a uniform, stable, slightly viscous light yellow suspension.

[0058] As a preferred implementation of this embodiment, it further includes adding fumed silica equivalent to 10% of its solid content to the suspension, mixing it evenly, and drying it to obtain a light yellow fine powder with good flowability.

[0059] The drying process is spray drying; the feed rate of the spray drying is 15 mL / min, the inlet air temperature is 145℃, and the outlet air temperature is 82℃.

[0060] The enhanced fertilizer described in this embodiment includes the fertilizer enhancer.

[0061] Example 5 The fertilizer synergist in this embodiment is obtained using the same raw materials and preparation method as in Example 4. The only difference is that the spray drying process parameters are set as follows: the feed rate of the spray drying is 15 mL / min, the inlet air temperature is 145℃, and the outlet air temperature is 95℃.

[0062] Example 6 The fertilizer synergist in this embodiment is obtained using the same raw materials and preparation method as in Example 4, the only difference being that the purity of N-acetylglucosamine is 90%.

[0063] Example 7 The fertilizer enhancer in this embodiment is obtained using the same raw materials and preparation method as in Example 4, the only difference being that malic acid is used instead of the mixture of citric acid and phytic acid, and malic acid is used as the nutrient enhancer.

[0064] Example 8 The fertilizer synergist in this embodiment is obtained using the same raw materials and preparation method as in Example 4, the only difference being that the weight of tannic acid is 20 parts.

[0065] Example 9 The fertilizer enhancer in this embodiment is obtained using the same raw materials and preparation method as in Example 4, the only difference being that the reaction temperature in step (2) is 80°C.

[0066] Example 10 The fertilizer enhancer in this embodiment is obtained using the same raw materials and preparation method as in Example 4, except that citric acid is used instead of the mixture of citric acid and phytic acid, and 12 parts of citric acid are used as the nutrient enhancer.

[0067] Example 11 The fertilizer enhancer in this embodiment is obtained using the same raw materials and preparation method as in Example 4, except that phytic acid is used instead of the mixture of citric acid and phytic acid, and 14 parts of citric acid are used as the nutrient enhancer.

[0068] Example 12 The fertilizer enhancer in this embodiment is obtained using the same raw materials and preparation method as in Example 4, except that phytic acid is used instead of the mixture of citric acid and phytic acid, and 12 parts of phytic acid are used as the nutrient enhancer.

[0069] Example 13 The fertilizer enhancer in this embodiment is obtained using the same raw materials and preparation method as in Example 4, the only difference being that phytic acid is used instead of the mixture of citric acid and phytic acid, and 14 parts of phytic acid are used as the nutrient enhancer.

[0070] Comparative Example 1 The fertilizer synergist in this comparative example was obtained using the same raw materials and preparation method as in Example 4, the only difference being that no adjuvants were added.

[0071] Comparative Example 2 The fertilizer synergist in this comparative example was obtained using the same raw materials and preparation method as in Example 4, the only difference being that no structural stabilizer was added.

[0072] Comparative Example 3 The fertilizer enhancer in this comparative example was obtained using the same raw materials and preparation method as in Example 4, except that acetic acid was used instead of the mixture of citric acid and phytic acid, and 12 parts of acetic acid were used as the nutrient enhancer.

[0073] Comparative Example 4 The fertilizer enhancer in this comparative example was obtained using the same raw materials and preparation method as in Example 4, except that polyglutamic acid was used instead of the mixture of citric acid and phytic acid, and 12 parts of acetic acid were used as the nutrient enhancer.

[0074] Effect Experiment Example To verify the technical effect of the fertilizer synergist described in this invention, the following experiments were conducted: The fertilizer synergists obtained in Examples 1-13 and Comparative Examples 1-4 were physically mixed with basic compound fertilizer at an addition rate of 5 wt‰, and the following experiments were conducted: Tomato seedlings (variety 'Golden Crown 5') were selected as the test subjects, and three treatment groups were set up: ① Control group: Only basic compound fertilizer was applied; ② Control group: Basic compound fertilizer + glucosamine (positive control group, glucosamine addition amount is 5wt‰). ③ Experimental Group: Basic compound fertilizer + fertilizer enhancers prepared in Examples 1-13 and Comparative Examples 1-4. The growth-promoting effect was evaluated by measuring plant height, stem diameter, fresh weight, dry weight, root morphology (total root length, root surface area), and relative chlorophyll content (SPAD value) of leaves 30 days after transplanting. Disease incidence was observed after artificial inoculation with early blight pathogens to preliminarily assess the induced disease resistance.

[0075] The growth-promoting effect can be expressed as the growth promotion rate: Growth promotion rate (%) = (X) 施肥30天后 -X 施肥前 ) / X 施肥前 ×100% X represents plant height (cm), stem diameter (mm), fresh weight (g), dry weight (g), total root length (cm), and root surface area (cm²). 2 ), SPAD value; calculate the growth promotion rate values ​​obtained when X takes plant height, stem diameter, fresh weight, dry weight, total root length, root surface area, and SPAD value, and take the average value to get the growth promotion rate referred to in this experimental example.

[0076] Disease resistance can be expressed by antibacterial efficiency. In this experimental case, the disease is defined as the period from inoculation with the early blight pathogen to the first visible lesions. Based on the area of ​​the lesions, the disease severity can be divided into the following 5 levels: Grade 0: No lesions; Grade 1: Lesion area <5%; Level 3: 5–25%; Level 5: >25% or leaves withered; Disease Index (DI) = ∑(Number of diseased leaves at each level × Representative value for that level) / (Total number of leaves × Highest level value) × 100% Antibacterial efficiency (%) = (DI) 施肥前 -DI 施肥30天后 ) / DI 施肥前 ×100% The results of the experiment are as follows:

[0077] Based on the above experimental results and Figure 1-2 It is understood that the fertilizer synergist described in this invention, when added to synergistic fertilizers, can effectively improve plant nutrient utilization, promote plant growth, and enhance plant stress resistance.

[0078] Based on the results of Example 4 and Comparative Examples 1-2, it is evident that the N-acetylglucosamine, nutrient enhancer, structural stabilizer, and adjuvant, when used in combination, have a synergistic effect, significantly impacting the growth promotion and antibacterial efficacy of tomato seedlings. Based on the results of Example 4, Comparative Examples 3-4, the blank group, and the control group, it is evident that acetic acid, as a monobasic acid, cannot chelate and stabilize micronutrients when added to the fertilizer synergist, leading to poor compatibility with the basal fertilizer and significantly affecting seedling growth and antibacterial performance. While polyglutamic acid can improve seedling growth and antibacterial performance to some extent compared to the control group, its high molecular chain structure easily leads to increased system viscosity and spatially hinders the effective approach of the pre-assembled body and structural stabilizer, thereby inhibiting the full progress of the covalent cross-linking reaction and ultimately reducing the overall performance of the fertilizer synergist.

[0079] Based on the results of Examples 4 and 5-9, it can be seen that the process parameters of spray drying affect product performance to a certain extent. Excessively high outlet air temperature negatively impacts the active ingredients and easily leads to adhesion and clumping. As a core component of fertilizer synergists, low purity of N-acetylglucosamine directly affects its application effect. Compared to citric acid (containing three carboxyl groups) and phytic acid (containing six phosphate groups), malic acid, as a dicarboxylic acid, has relatively poor bridging ability and cannot effectively promote multi-point non-covalent cross-linking between deacetylated N-acetylglucosamine and the structural stabilizer, resulting in decreased uniformity and stability of the composite system, thus reducing the overall performance of the fertilizer synergist. Excessive addition of tannic acid, as a structural stabilizer, leads to excessive cross-linking, affecting the release of the core component and thus the overall performance of the fertilizer synergist. While reaction temperatures above 70℃ can accelerate the reaction rate, they can also induce thermal degradation of deacetylated N-acetylglucosamine to a certain extent, leading to a decrease in the effective content of the core component and thus affecting the overall performance of the fertilizer synergist.

[0080] Based on the results of Examples 4 and 10-13, it is evident that compared to using citric acid or phytic acid alone, the nutrient enhancer, employing a combination of citric acid and phytic acid, can improve growth promotion and antibacterial effects. Simply increasing the dosage of either citric acid or phytic acid does not achieve better results. This may be due to differences in charge density and chelating ability between phytic acid and citric acid. Phytic acid exhibits higher complexation stability but may result in an overly dense local structure in the pre-assembled structure, leading to uneven network structure during subsequent cross-linking. Citric acid, on the other hand, can regulate steric hindrance, making the structure more uniform. When used in combination, the resulting fertilizer enhancer has a structure more conducive to its function.

[0081] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are encompassed by this invention.

Claims

1. A fertilizer synergist, characterized in that, The ingredients include the following parts by weight: 20-50 parts of N-acetylglucosamine, 10-30 parts of nutritional enhancer, 1-15 parts of structural stabilizer, and 5-20 parts of auxiliary agent; The nutrient enhancer is an organic acid or its derivative having two or more carboxyl or phosphate groups, or an organic acid or its derivative having both carboxyl and phosphate groups.

2. The fertilizer synergist according to claim 1, characterized in that, The purity of the N-acetylglucosamine is ≥95%; Optionally, the N-acetylglucosamine is prepared by microbial fermentation.

3. The fertilizer synergist according to claim 1, characterized in that, The nutrient enhancer is one or more of citric acid, phytic acid and their salts; Optionally, the structural stabilizer is one of tannic acid and genipin; Optionally, the adjuvant is one or more of lecithin, alkyl glycoside, and silicate.

4. A method for preparing a fertilizer synergist according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Dissolve N-acetylglucosamine and nutrient enhancer in a solvent to obtain a premix; (2) Add a structure stabilizer to the premixed liquid obtained in step (1) and react to obtain the modified product; (3) Add the additive to the modified product obtained in step (2) and mix evenly to obtain the final product.

5. The method for preparing the fertilizer synergist according to claim 4, characterized in that, In step (1), the solvent is one of water or an aqueous solution of a C1-C6 fatty alcohol; Optionally, the concentration of the N-acetylglucosamine in the solvent is 50-100 g / L; Optionally, the N-acetylglucosamine and the nutrient enhancer are dissolved in the solvent at a temperature of 30-50°C.

6. The method for preparing the fertilizer synergist according to claim 4, characterized in that, In step (2), the reaction is carried out at a pH of 7.5-9.0 and a temperature of 50-70℃ for 2-6 hours with stirring. Optionally, in step (2), the structure stabilizer is first dissolved in a solvent and then added dropwise to the premixed solution.

7. The method for preparing the fertilizer synergist according to claim 4, characterized in that, In step (3), homogenization is used to mix the modified product and the additive evenly.

8. The method for preparing the fertilizer synergist according to claim 4, characterized in that, Step (3) also includes a drying step; Optionally, the drying is spray drying; the inlet air temperature of the spray drying is 120-160℃, and the outlet air temperature is 70-90℃.

9. The method for preparing the fertilizer synergist according to claim 4, characterized in that, Step (3) also includes a concentration and granulation step; Optionally, the concentration and granulation process involves vacuum concentration followed by fluidized bed granulation.

10. A synergistic fertilizer, characterized in that, Includes the fertilizer enhancer as described in any one of claims 1-3.

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