Alginic acid organic water-soluble fertilizer capable of quickly releasing nutrients and preparation method of alginic acid organic water-soluble fertilizer

Abstract

The invention relates to the technical field of fertilizers, in particular to an alginic acid organic water-soluble fertilizer capable of quickly releasing nutrients and a preparation method of the alginic acid organic water-soluble fertilizer. The organic water-soluble fertilizer is prepared from the following preparation raw materials: 30 to 35 parts of sodium alginate, 12 to 15 parts of a seaweed extract composition, 5 to 8 parts of monocalcium phosphate, 5 to 8 parts of monopotassium phosphate, 12 to 15 parts of urea, 0.5 to 0.8 part of a chelating agent, 40 to 45 parts of an organic fertilizer raw material, 1.5 to 2 parts of a microbial strain, 12 to 16 parts of ammonium humate, 4 to 6 parts of a cosolvent and 1.4 to 1.7 parts of xanthan gum. By optimizing the ratio of the raw materials, the absorption and utilization rate of plants to the water-soluble fertilizer is remarkably improved; nutritional ingredients can be quickly released, and plants can be promoted to absorb water-soluble fertilizer; through the synergistic effect of microorganisms and organic components, the content of nutrient substances in soil is increased, plants are helped to better absorb mineral substances and trace elements, the utilization efficiency of the fertilizer is improved, healthy growth of the plants is promoted, and the yield is increased.

Description

Technical Field

[0001] This application relates to the field of fertilizer technology, and in particular to an alginate organic water-soluble fertilizer that can rapidly release nutrients and its preparation method. Background Technology

[0002] Organic water-soluble fertilizer is a type of organic fertilizer that can completely dissolve in water. It is made from natural organic matter through a special process. During processing, these raw materials undergo microbial fermentation or enzymatic hydrolysis to break them down into highly active small-molecule organic substances. It is then combined with macronutrients such as nitrogen, phosphorus, and potassium, as well as micronutrients such as calcium, magnesium, zinc, and boron, forming a fully water-soluble, highly concentrated, multifunctional, and nutritionally complete synergistic fertilizer product. With its unique composition and mechanism of action, organic water-soluble fertilizer plays a vital role in improving soil structure, enhancing soil fertility, and promoting the soil's ecological environment. In future agricultural development, with increasing emphasis on environmental protection and health, the application prospects of organic water-soluble fertilizer will be even broader.

[0003] The current organic water-soluble fertilizer market is dominated by slow-release products, which extend the nutrient release cycle through large particle design. However, they cannot meet the rapid demand for nutrients in the early stages of crop growth, and long-term use will still lead to soil compaction. In addition, water-soluble fertilizers also have some problems during storage and transportation, such as gas expansion and crystallization. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a rapidly releasing alginic acid organic water-soluble fertilizer and its preparation method. The raw materials in the rapidly releasing alginic acid organic water-soluble fertilizer prepared in this application are well-proportioned, improving the absorption and utilization rate of water-soluble fertilizers by plants. It can rapidly release nutrients, promoting plant absorption of water-soluble fertilizers. Through the synergistic effect of microorganisms and organic components, it increases the content of nutrients in the soil and helps plants better absorb minerals and trace elements, improving fertilizer utilization efficiency, reducing fertilizer loss, promoting healthy plant growth, and increasing yield. This application achieves a balance between rapid nutrient release and sustained supply by combining sodium alginate carrier, seaweed extract composition, and microbial fermentation technology, while also taking into account environmental friendliness. The seaweed extract composition retains a wider variety of nutrients and beneficial elements, making it easier for plants to absorb and utilize. In addition, the seaweed extract composition prepared in this application has a high content of alginic acid and seaweed polysaccharides, as well as glycosidic bonds and sulfate groups, which work synergistically with the stabilizer xanthan gum to significantly improve the storage stability of water-soluble fertilizers, prevent gas expansion and crystallization, and increase soil porosity.

[0005] In a first aspect, this application provides a seaweed acid organic water-soluble fertilizer that can rapidly release nutrients, employing the following technical solution: A water-soluble organic fertilizer containing alginic acid that can rapidly release nutrients comprises, by weight, the following raw materials: 30-35 parts sodium alginate, 12-15 parts seaweed extract composition, 5-8 parts calcium dihydrogen phosphate, 5-8 parts potassium dihydrogen phosphate, 12-15 parts urea, 0.5-0.8 parts chelating agent, 40-45 parts organic fertilizer raw material, 1.5-2 parts microbial inoculum, 12-16 parts humic acid ammonia, 4-6 parts solubilizer, and 1.4-1.7 parts xanthan gum.

[0006] By employing the above technical solutions, sodium alginate is constructed into a colloidal framework, forming a three-dimensional network structure to encapsulate nutrients, achieving a balance between slow and rapid release. Xanthan gum forms an interpenetrating network structure with sodium alginate through hydrogen bonds, enhancing colloidal stability; its carboxyl groups interact with metal ions (such as Ca²⁺) to form an interpenetrating network structure. 2+ K + This combination prevents nutrient precipitation. Seaweed extract composition: provides alginic acid, polysaccharides, natural hormones (such as auxins and cytokinins), and trace elements. Glycosidic bonds and sulfate groups bind xanthan gum through hydrogen bonds, enhancing the colloid's water-holding capacity; polysaccharides interact with microbial metabolites, promoting bacterial activity. Phosphate system (calcium dihydrogen phosphate + potassium dihydrogen phosphate): directly supplies phosphorus, potassium, and calcium nutrients. Calcium ions cross-link with sodium alginate to form a gel structure, regulating the nutrient release rate; phosphate ions and humic ammonia stabilize nitrogen through hydrogen bonds. Urea: a high-concentration nitrogen source that rapidly releases ammonium nitrogen through hydrolysis. Microbial flora secrete urease to accelerate urea decomposition, while humic ammonia buffers pH fluctuations, reducing ammonia volatilization. Chelating agents (such as disodium EDTA): chelate Fe... 3+ Zn 2+ It contains metal ions to prevent nutrient fixation. It forms a competitive complex with the polyhydroxy structure of alginic acid, preferentially protecting the availability of trace elements. Organic fertilizer raw materials (such as soybean meal + glucose + amino acids) provide carbon and nitrogen sources: soybean meal provides slow-release organic nitrogen, and glucose is a rapid carbon source for microorganisms. Optimized amino acid ratios: glutamic acid (promotes photosynthesis), aspartic acid (nitrogen transport), and lysine (enzyme activation) synergistically enhance metabolic activity. Microbial strains (such as Bacillus subtilis + phosphate-solubilizing bacteria + potassium-solubilizing bacteria): Bacillus subtilis secretes antibacterial substances to inhibit soil-borne diseases; phosphate-solubilizing bacteria mineralize organic phosphorus into soluble phosphorus; potassium-solubilizing bacteria release potassium from silicate minerals. Organic acids produced by microbial metabolism synergistically activate soil nutrients with humic acid. Solubilizers (such as potassium citrate): These act as both a potassium source and, through citrate complexation of high-valence cations, prevent precipitation. They form a chelation gradient with disodium EDTA, preferentially chelating high-affinity ions (such as Fe). 3+ This reduces EDTA consumption. Humic acid ammonia: a cation exchange carrier, adsorbs NH4+. + K +Plasma reduces nutrient loss. Blending with xanthan gum increases colloidal viscoelasticity and slows nutrient diffusion. Xanthan gum: Shear-thinning properties ensure sprinkler flowability, and high viscosity is restored after settling to prevent stratification. It forms an interpenetrating network structure with sodium alginate, enhancing resistance to salt leaching. System-level synergistic effects: 1) Fast-acting and slow-release dual modes: Urea and phosphate dissolve rapidly to provide fast-acting nutrients. The sodium alginate / xanthan gum gel network controls the slow release of organic nitrogen (soybean meal) and microbial metabolites. 2) Microbial-chemical coupling: Phosphate-solubilizing bacteria / potassium-solubilizing bacteria activate inherent soil nutrients, EDTA chelates for enhanced efficiency, and reduces fertilizer input. 3) Enhanced stability: Xanthan gum inhibits crystallization (through steric hindrance), potassium citrate regulates pH, and reduces the risk of bloating (reducing anaerobic fermentation). 4) Soil improvement: Humic acid ammonia increases cation exchange capacity (CEC), and seaweed polysaccharides promote aggregate formation and increase porosity. In summary, by coordinating the colloidal network (sodium alginate + xanthan gum) with the timing of microbial activity, the nutrient release curve is matched with plant needs. The chelating competition mechanism between the chelating agent and potassium citrate reduces the amount of chelating agent required while ensuring the availability of micronutrients. All components are biodegradable, and the seaweed extract and microbial community synergistically reduce chemical fertilizer residues. This formula, through multi-component functional complementarity and cascade reaction design, extends the fertilizer effect cycle while ensuring rapid effectiveness and improving overall utilization.

[0007] Preferably, the method for preparing the seaweed extract composition includes the following steps: S21. Remove impurities and foreign objects from the brown algae and rinse them thoroughly with clean water. S22. Add the washed brown algae to a homogenizer and add 2-3 times the volume of pure water. Shear at 3000-4000 rpm for 40-50 minutes to obtain brown algae homogenate. S23. Place the brown algae homogenate into an ultrasonic cell disruptor and ultrasonically disrupt it for 8-12 minutes to further break down the brown algae cells and completely release their intracellular contents to obtain brown algae slurry. S24. According to the mass fractions, mix the brown algae slurry, the 3.5wt% potassium hydroxide aqueous solution and xanthan gum evenly, heat to 50-55℃ and react for 3-4 hours, cool to room temperature, centrifuge and filter to obtain the seaweed extract composition.

[0008] By adopting the above technical solution, step S21: raw material pretreatment removes foreign matter such as mud and marine organisms, reducing interference factors in subsequent extraction. It also reduces salt content (avoiding sodium). +(Cl- interferes with subsequent reactions). Brown algae are rich in alginic acid, fucoidan, and other components, but impurities may affect the pH and chelation efficiency of the reaction system. Step S22: High-speed shear homogenization physically breaks down the algal cell walls (brown algal cell walls contain a cellulose-algin complex structure), releasing intracellular active substances. This forms a homogeneous suspension, increasing the contact area for subsequent reactions. Step S23: Ultrasonic disruption is enhanced, utilizing cavitation to further break down the residual cell wall structure, releasing bound polysaccharides and trace elements (such as iodine and zinc in brown algae). This breaks down large polysaccharide chains, increasing water solubility (e.g., dissociating alginic acid from the cell wall network structure). Synergistic effect: Ultrasonic assistance increases the yield of alginic acid by 15-20% while retaining sulfate groups (key functional groups). Step S24: Alkaline hydrolysis and xanthan gum compounding. Alkaline hydrolysis: KOH promotes the conversion of calcium / magnesium alginate into soluble potassium alginate; Polysaccharide modification: Under alkaline conditions, β-1,4 glycosidic bonds are broken, generating low molecular weight alginate fragments, enhancing plant absorption. Xanthan gum and alginate form a complex colloid through hydrogen bonds, inhibiting polysaccharide chain repolymerization. The sulfate groups (from brown algae polysaccharides) are electrostatically attracted to the acetyl groups of xanthan gum, enhancing thermal stability. Centrifugation and filtration remove unreacted cellulose residue, retaining soluble active ingredients. The core functional component of the prepared seaweed extract composition is alginate, which acts as a natural chelating agent, binding Ca... 2+ Mg 2+ It contains metal ions to prevent fertilizer crystallization. Brown algae polysaccharides: contain sulfate groups (-OSO3). - It adsorbs soil moisture through hydrogen bonds, extending the fertilizer's effective period. Natural hormones: cytokinins, auxins, etc., stimulate plant root development (synergistic effect with humic acid and ammonia). Synergistic effect with xanthan gum enhances storage stability: the composite colloidal network inhibits microbial fermentation and gas production (CO2, NH3), avoiding bag bloating. Innovative preparation process: 1) Dual-stage crushing technology: high-speed shearing (macroscopic crushing) combined with ultrasonic cavitation (microscopic dissociation) achieves efficient release of cell contents (extraction rate > 85%). 2) In-situ stabilization design: xanthan gum is added directly during the alkaline hydrolysis stage to avoid the re-aggregation of alginate degradation products and maintain molecular weight distribution (1-10kDa is the optimal activity range). 3) Low-temperature alkaline hydrolysis control: reaction temperature ≤ 55℃ to prevent desulfurization of sulfate groups (high temperature leads to functional loss) while retaining the activity of natural hormones. In summary, low molecular weight alginate and potassium citrate synergistically dissolve phosphate, rapidly releasing nutrients. The alginate-xanthan gum gel network encapsulates organic fertilizer raw materials (soybean flour, etc.), which slowly degrade in the soil to provide fertilizer. Sulfated polysaccharides promote the proliferation of soil actinomycetes and increase soil porosity. This preparation method, through multi-step synergistic regulation, achieves efficient extraction and functional enhancement of seaweed active ingredients, which is a key guarantee for the rapid effectiveness and environmental adaptability of fertilizers.

[0009] Preferably, in step S23, the power of the ultrasonic cell disruptor is 3-5kW.

[0010] Preferably, in step S24, the mass ratio of the brown algae slurry, the 3.5wt% potassium hydroxide aqueous solution, and xanthan gum is 100:20-25:1.

[0011] Preferably, the organic fertilizer raw materials include 20-25 parts soybean flour, 10-15 parts glucose, and 5-8 parts amino acids.

[0012] Preferably, the amino acid is composed of glutamic acid, aspartic acid and lysine in a mass ratio of 4:3:1-2.

[0013] Preferably, the microbial strain is at least two of Bacillus subtilis, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria, and the viable count of the Bacillus subtilis is 5-7 × 10⁻⁶. 8 CFU / g, the viable count of the phosphate-solubilizing bacteria is 3-5 × 10⁻⁵. 7 CFU / g, the viable count of the potassium-solubilizing bacteria is 1-3 × 10⁻⁶. 8 CFU / g.

[0014] Preferably, the co-solvent is potassium citrate.

[0015] Preferably, the chelating agent is disodium ethylenediaminetetraacetate.

[0016] Secondly, this application provides a method for preparing a seaweed acid organic water-soluble fertilizer that can rapidly release nutrients, using the following technical solution: As a general technical concept, this application also provides a method for preparing the above-mentioned alginic acid organic water-soluble fertilizer that can rapidly release nutrients, including the following steps: S101. Mix the organic fertilizer raw materials and water evenly according to the mass ratio of 1:1.5, inoculate with microbial inoculum, and ferment at 28-32℃ for 48-72 hours to obtain fermentation liquid; S102. According to the mass proportions, the fermentation broth, sodium alginate, seaweed extract composition, calcium dihydrogen phosphate, potassium dihydrogen phosphate, urea, chelating agent, humic acid ammonia, co-solvent and xanthan gum are mixed evenly, and then granulated by spray drying to control the particle size to 1-3mm, so as to obtain a seaweed acid organic water-soluble fertilizer that can quickly release nutrients.

[0017] In summary, this application includes at least one of the following beneficial technical effects: 1. Rapid nutrient release: It can release nutrients in a short time, promoting rapid absorption by plants.

[0018] 2. Improve fertilizer utilization: Through the combination of various components, nutrient loss is reduced and the overall utilization rate of fertilizer is improved.

[0019] 3. Improves soil structure: Increases soil porosity, which helps maintain soil aeration and water retention capacity.

[0020] 4. Promotes crop growth: It can promote root development, enhance crop resistance to adverse conditions, and thus improve crop yield and quality.

[0021] 5. Environmentally friendly: All components are biodegradable, have little impact on the environment, and can reduce chemical fertilizer residues. Detailed Implementation

[0022] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0023] In the following examples and preparation examples, 1 part represents 100g, and the viable count of Bacillus subtilis is 6 × 10⁻⁶. 8 CFU / g, the viable count of the phosphate-solubilizing bacteria is 4 × 10⁻⁶. 7 CFU / g, the viable count of the potassium-solubilizing bacteria is 2×10⁻⁶. 8 CFU / g.

[0024] Preparation Example 1: Preparation of Seaweed Extract Composition The method for preparing the seaweed extract composition includes the following steps: S21. Remove impurities and foreign objects from the brown algae and rinse them thoroughly with clean water. S22. Add the washed brown algae to a homogenizer and add 2.3 times the volume of pure water. Shear at 3500 rpm for 45 minutes to obtain a brown algae homogenate. S23. Place the brown algae homogenate into an ultrasonic cell disruptor and ultrasonically disrupt it for 10 minutes at a power of 4kW to further break down the brown algae cells and completely release their intracellular contents to obtain brown algae slurry. S24. According to the mass fractions, 100 parts of brown algae slurry, 22 parts of 3.5wt% potassium hydroxide aqueous solution and 1 part of xanthan gum are mixed evenly, heated to 53℃ and reacted for 3.4 hours, cooled to room temperature, centrifuged and filtered to obtain the seaweed extract composition.

[0025] Example 1 A rapidly releasing nutrient-rich alginic acid organic water-soluble fertilizer, by weight, comprises the following raw materials: 30 parts sodium alginate, 12 parts seaweed extract composition, 5 parts calcium dihydrogen phosphate, 5 parts potassium dihydrogen phosphate, 12 parts urea, 0.5 parts disodium EDTA, 40 parts organic fertilizer raw materials, 1.5 parts microbial inoculum, 12 parts humic acid ammonia, 4 parts potassium citrate, and 1.4 parts xanthan gum. The organic fertilizer raw materials include 20 parts soybean flour, 10 parts glucose, and 5 parts amino acids. The amino acids are composed of glutamic acid, aspartic acid, and lysine in a weight ratio of 4:3:1. The microbial inoculum is composed of Bacillus subtilis and phosphate-solubilizing bacteria in a weight ratio of 1:2. The preparation method of the above-mentioned seaweed acid organic water-soluble fertilizer that can rapidly release nutrients includes the following steps: S101. Mix the organic fertilizer raw materials and water evenly according to the mass ratio of 1:1.5, inoculate with microbial inoculum, and ferment at 28℃ for 72 hours to obtain fermentation liquid; S102. According to the mass proportions, the fermentation broth, sodium alginate, seaweed extract composition, calcium dihydrogen phosphate, potassium dihydrogen phosphate, urea, disodium EDTA, ammonium humate, potassium citrate and xanthan gum are mixed evenly, and then granulated by spray drying to control the particle size to 1-3 mm, so as to obtain a seaweed acid organic water-soluble fertilizer that can quickly release nutrients.

[0026] Example 2 A rapidly releasing nutrient-rich alginic acid organic water-soluble fertilizer, by weight, comprises the following raw materials: 35 parts sodium alginate, 15 parts seaweed extract composition, 8 parts calcium dihydrogen phosphate, 8 parts potassium dihydrogen phosphate, 15 parts urea, 0.8 parts disodium EDTA, 45 parts organic fertilizer raw materials, 2 parts microbial inoculum, 16 parts humic acid ammonia, 6 parts potassium citrate, and 1.7 parts xanthan gum. The organic fertilizer raw materials include 25 parts soybean meal, 15 parts glucose, and 8 parts amino acids. The amino acids are composed of glutamic acid, aspartic acid, and lysine in a weight ratio of 4:3:2. The microbial inoculum is composed of Bacillus subtilis and potassium-solubilizing bacteria in a weight ratio of 2:1. The preparation method of the above-mentioned seaweed acid organic water-soluble fertilizer that can rapidly release nutrients includes the following steps: S101. Mix the organic fertilizer raw materials and water evenly according to the mass ratio of 1:1.5, inoculate with microbial inoculum, and ferment at 32℃ for 48 hours to obtain fermentation liquid; S102. According to the mass proportions, the fermentation broth, sodium alginate, seaweed extract composition, calcium dihydrogen phosphate, potassium dihydrogen phosphate, urea, disodium EDTA, ammonium humate, potassium citrate and xanthan gum are mixed evenly, and then granulated by spray drying to control the particle size to 1-3 mm, so as to obtain a seaweed acid organic water-soluble fertilizer that can quickly release nutrients.

[0027] Example 3 A rapidly releasing nutrient-rich alginic acid organic water-soluble fertilizer comprises, by weight, the following raw materials: 33 parts sodium alginate, 14 parts seaweed extract composition, 7 parts calcium dihydrogen phosphate, 6 parts potassium dihydrogen phosphate, 13 parts urea, 0.6 parts disodium EDTA, 43 parts organic fertilizer raw materials, 1.7 parts microbial inoculum, 14 parts humic acid ammonia, 5 parts potassium citrate, and 1.5 parts xanthan gum. The organic fertilizer raw materials include 22 parts soybean flour, 13 parts glucose, and 7 parts amino acids. The amino acids are composed of glutamic acid, aspartic acid, and lysine in a weight ratio of 4:3:1.5. The microbial inoculum is composed of phosphate-solubilizing bacteria and potassium-solubilizing bacteria in a weight ratio of 1:2. The preparation method of the above-mentioned seaweed acid organic water-soluble fertilizer that can rapidly release nutrients includes the following steps: S101. Mix the organic fertilizer raw materials and water evenly according to the mass ratio of 1:1.5, inoculate with microbial inoculum, and ferment at 30℃ for 60 hours to obtain fermentation liquid; S102. According to the mass proportions, the fermentation broth, sodium alginate, seaweed extract composition, calcium dihydrogen phosphate, potassium dihydrogen phosphate, urea, disodium EDTA, ammonium humate, potassium citrate and xanthan gum are mixed evenly, and then granulated by spray drying to control the particle size to 1-3 mm, so as to obtain a seaweed acid organic water-soluble fertilizer that can quickly release nutrients.

[0028] Example 4 A rapidly releasing nutrient-rich alginic acid organic water-soluble fertilizer comprises, by weight, the following raw materials: 34 parts sodium alginate, 14 parts seaweed extract composition, 7 parts calcium dihydrogen phosphate, 6 parts potassium dihydrogen phosphate, 14 parts urea, 0.7 parts disodium EDTA, 44 parts organic fertilizer raw materials, 1.6 parts microbial strains, 13 parts humic acid ammonia, 5 parts potassium citrate, and 1.5 parts xanthan gum. The organic fertilizer raw materials include 24 parts soybean flour, 12 parts glucose, and 7 parts amino acids. The amino acids are composed of glutamic acid, aspartic acid, and lysine in a weight ratio of 4:3:1.5. The microbial strains are composed of Bacillus subtilis, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria in a weight ratio of 1:2:1. The preparation method of the above-mentioned seaweed acid organic water-soluble fertilizer that can rapidly release nutrients includes the following steps: S101. Mix the organic fertilizer raw materials and water evenly according to the mass ratio of 1:1.5, inoculate with microbial inoculum, and ferment at 30℃ for 60 hours to obtain fermentation liquid; S102. According to the mass proportions, the fermentation broth, sodium alginate, seaweed extract composition, calcium dihydrogen phosphate, potassium dihydrogen phosphate, urea, disodium EDTA, ammonium humate, potassium citrate and xanthan gum are mixed evenly, and then granulated by spray drying to control the particle size to 1-3 mm, so as to obtain a seaweed acid organic water-soluble fertilizer that can quickly release nutrients.

[0029] Comparative Example 1 Same as Example 4, except that no seaweed extract composition was added.

[0030] Performance testing 1. Film-forming properties and storage test: The alginic acid organic water-soluble fertilizers that can rapidly release nutrients prepared in Examples 1-4 and Comparative Example 1 were diluted with water to prepare 0.1% foliar fertilizers, which were then sprayed on spinach leaves. One hour after spraying, the stomatal opening of the spinach leaves after spraying with the foliar fertilizer was observed using an optical microscope, with water as a control. The alginic acid organic water-soluble fertilizers that can rapidly release nutrients prepared in Examples 1-3 and Comparative Example 2 were packaged and placed at 15℃ and 40℃ for 365 days, respectively, to check the physical properties of the water-soluble fertilizers and the packaging conditions. The results are shown in Table 1.

[0031] 2. The impact of water-soluble fertilizers on soil porosity in greenhouses The experimental site was located in the Jimo District Experimental Base of Qingdao City, Shandong Province. The planting system was rice-wheat rotation. The experiment was conducted on rice plants, with seedlings raised at the end of April 2024, transplanted in early June, and harvested in early October. The soil organic matter content of the tested soil type was 12.57 g / kg, total phosphorus 0.70 g / kg, total nitrogen 1.04 g / kg, total potassium 1.45 g / kg, available phosphorus 25.12 mg / kg, available potassium 213.45 mg / kg, available nitrogen 48.36 mg / kg, and pH value 8.1.

[0032] A single-factor design was used, with 5 treatments, each replicated 4 times. The experimental area was 15m × 15m, resulting in 20 blocks arranged in a randomized block design. Water-soluble fertilizer solutions were prepared at a dilution of 400 times, and sprayed at 7-day intervals. All agronomic practices were consistent except for the fertilizer used. Soil porosity was determined using the ring sampler method. The calculation formula is as follows: Total soil porosity = [1 - (bulk density / specific gravity)] × 100%, where the soil specific gravity is 2.62 g / cm³. 3 Water was used as the control group. The test results are shown in Table 2.

[0033] 3. Rice yield testing: Based on the principle of zoning, rice yields from each zone will be collected for yield testing. The results are shown in Table 3.

[0034] 4. Release rate test: The alginic acid prepared in Examples 1-4 and Comparative Example 1, which can rapidly release nutrients, was tested for its nutrient slow-release effect according to the method of international standard ISO18644 "Fertilizers and soil conditioners - General requirements for controlled-release fertilizers" (2016). The urea release rate was tested, and the results are shown in Table 4.

[0035] Table 1. Results of film-forming properties and storage tests Table 2 Soil porosity test results project Total soil porosity / % Example 1 52.2 Example 2 52.3 Example 3 52.4 Example 4 52.9 Comparative Example 1 50.3 control group 42.6 Table 3. Rice yield test results project <![CDATA[Yield (kg / hm 2 )]]> Example 1 13746±453.68 Example 2 13835±303.21 Example 3 13901±245.43 Example 4 13987±201.56 Comparative Example 1 10896±412.62 Table 4 Release Rate Test Analyzing the data in Tables 1-4, we can see that: 1) The alginic acid organic water-soluble fertilizers prepared in Examples 1-4 that can rapidly release nutrients have excellent storage stability, are not prone to gas expansion, do not crystallize, and have good soil porosity and field test results. At the same time, they can rapidly release nutrients.

[0036] 2) The performance comparison analysis of the alginic acid organic water-soluble fertilizer prepared in Example 4 and Comparative Example 1 shows that the seaweed extract composition prepared in this application has more alginic acid and seaweed polysaccharides, as well as glycosidic bonds and sulfate groups, which significantly improves the storage stability of the water-soluble fertilizer, makes it less prone to gas swelling and crystallization, and has better soil porosity and field test results. At the same time, it can quickly release nutrients.

[0037] The above embodiments are only used to explain the technical solutions of this application and are not intended to limit it. Although the above embodiments have provided specific descriptions of this application, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation methods of this application. Any modifications and equivalent substitutions that do not depart from the spirit and scope of this application should be covered within the protection scope of this application.

Claims

1. A seaweed-based organic water-soluble fertilizer that can rapidly release nutrients, characterized in that, The preparation materials, by weight, include the following raw materials: 30-35 parts sodium alginate, 12-15 parts seaweed extract composition, 5-8 parts calcium dihydrogen phosphate, 5-8 parts potassium dihydrogen phosphate, 12-15 parts urea, 0.5-0.8 parts chelating agent, 40-45 parts organic fertilizer raw materials, 1.5-2 parts microbial inoculum, 12-16 parts humic acid ammonium, 4-6 parts solubilizer, and 1.4-1.7 parts xanthan gum.

2. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 1, characterized in that, The preparation method of the seaweed extract composition includes the following steps: S21. Remove impurities and foreign objects from the brown algae and rinse them thoroughly with clean water. S22. Add the washed brown algae to a homogenizer and add 2-3 times the volume of pure water. Shear at 3000-4000 rpm for 40-50 minutes to obtain brown algae homogenate. S23. Place the brown algae homogenate into an ultrasonic cell disruptor and ultrasonically disrupt it for 8-12 minutes to further break down the brown algae cells and completely release their intracellular contents to obtain brown algae slurry. S24. According to the mass fractions, mix the brown algae slurry, the 3.5wt% potassium hydroxide aqueous solution and xanthan gum evenly, heat to 50-55℃ and react for 3-4 hours, cool to room temperature, centrifuge and filter to obtain the seaweed extract composition.

3. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 2, characterized in that, In step S23, the power of the ultrasonic cell disruptor is 3-5kW.

4. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 2, characterized in that, In step S24, the mass ratio of the brown algae slurry, the 3.5wt% potassium hydroxide aqueous solution, and xanthan gum is 100:20-25:

1.

5. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 1, characterized in that, The organic fertilizer raw materials include 20-25 parts soybean flour, 10-15 parts glucose, and 5-8 parts amino acids.

6. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 5, characterized in that, The amino acid is composed of glutamic acid, aspartic acid and lysine in a mass ratio of 4:3:1-2.

7. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 1, characterized in that, The microbial strains are at least two of Bacillus subtilis, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria, and the viable count of Bacillus subtilis is 5-7 × 10⁻⁶. 8 CFU / g, the viable count of the phosphate-solubilizing bacteria is 3-5 × 10⁻⁵. 7 CFU / g, the viable count of the potassium-solubilizing bacteria is 1-3 × 10⁻⁶. 8 CFU / g.

8. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 1, characterized in that, The co-solvent is potassium citrate.

9. The alginic acid organic water-soluble fertilizer that can rapidly release nutrients according to claim 1, characterized in that, The chelating agent is disodium ethylenediaminetetraacetate.

10. A method for preparing a rapidly releasing nutrient-rich alginate organic water-soluble fertilizer as described in any one of claims 1-9, characterized in that, Includes the following steps: S101. Mix the organic fertilizer raw materials and water evenly according to the mass ratio of 1:1.5, inoculate with microbial inoculum, and ferment at 28-32℃ for 48-72 hours to obtain fermentation liquid; S102. According to the mass proportions, the fermentation broth, sodium alginate, seaweed extract composition, calcium dihydrogen phosphate, potassium dihydrogen phosphate, urea, chelating agent, humic acid ammonia, co-solvent and xanthan gum are mixed evenly, and then granulated by spray drying to control the particle size to 1-3mm, so as to obtain a seaweed acid organic water-soluble fertilizer that can quickly release nutrients.

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