Seaweed organic water-soluble fertilizer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of fertilizer preparation, and particularly discloses a seaweed organic water-soluble fertilizer and a preparation method and application thereof, the seaweed organic water-soluble fertilizer is prepared by mixing an orange peel extract and a seaweed extract according to a volume ratio of 2: (2-5) and then freeze-drying; the orange peel extract is prepared by the following steps: performing alcohol extraction and solid-liquid separation on fresh orange peel, collecting precipitates, performing water extraction on the precipitates to obtain a water extract, adding a compound enzyme preparation for enzymolysis to obtain an enzyme extract, performing solid-liquid separation, collecting clear liquid, and performing vacuum concentration. The seaweed extract is obtained by taking seaweed as a raw material, adding dipotassium phosphate and potassium citrate as media to create an alkaline environment and carrying out enzymolysis extraction. The seaweed organic water-soluble fertilizer provided by the invention is used for improving the drought resistance and salt resistance of wheat, and is used for promoting the growth and development of wheat under drought stress and salt stress.

Description

Technical Field

[0001] This invention relates to the field of fertilizer technology, specifically to a seaweed organic water-soluble fertilizer, its preparation method, and its application. Background Technology

[0002] Climate change is leading to frequent droughts, and wheat is one of the world's three major food crops. Traditional fertilizers, which contain added hormones or chemically synthesized plant growth regulators and other non-natural ingredients, can easily cause premature aging of crops with long-term use, and even lead to soil pollution and green and healthy issues in agricultural products. Traditional fertilizers tend to overlook their impact on wheat roots, thus neglecting the nutrient absorption capacity of wheat roots, resulting in poor root growth and difficulty in coping with the effects of drought stress.

[0003] Water-soluble fertilizer (WSF) is a multi-element compound fertilizer that can be completely dissolved in water. It features high-efficiency absorption, precise fertilization, and resource conservation, and is widely used in modern agriculture.

[0004] Therefore, there is an urgent need to provide a water-soluble fertilizer that can both promote wheat growth and resist drought. Summary of the Invention

[0005] To develop a water-soluble fertilizer that promotes wheat growth and reduces stress, this invention provides a seaweed organic water-soluble fertilizer, its preparation method, and its application. The seaweed organic water-soluble fertilizer provided by this invention is beneficial for promoting wheat growth and development, and can be used to promote wheat growth and development under drought stress, thereby improving wheat's drought resistance.

[0006] This invention provides a seaweed organic water-soluble fertilizer, which is prepared by freeze-drying a mixture of orange peel extract and seaweed extract at a volume ratio of 2:2 to 5. The orange peel extract is obtained by extracting fresh orange peel with alcohol, separating solid and liquid, collecting the precipitate, extracting the precipitate with water, adding a compound enzyme preparation for enzymatic hydrolysis to obtain an enzyme extract, separating solid and liquid, collecting the clear liquid, and concentrating it under vacuum to obtain the orange peel extract. The seaweed extract is prepared by the following steps: using seaweed as raw material, water is added and mixed, followed by the addition of 15%–30% by mass of dipotassium hydrogen phosphate and 10%–20% by mass of potassium citrate. The pH is adjusted to 9–11, and the seaweed is extracted by intermittent stirring. Then, according to the seaweed mass percentage, 1%–4% alginate lyase, 0.1%–0.5% hupro protease, 0.2%–0.5% neutral protease, 2%–5% cellulase, 1%–3% hemicellulase, and 2%–4% ligninase are added sequentially for enzymatic extraction. The seaweed extract is obtained by filtration. The seaweed is composed of *Sargassum fusiforme*, *Sargassum bark*, and *Sargassum fusiforme* in a mass ratio of 3–4:1–2:1–2.

[0007] The seaweed organic water-soluble fertilizer provided by this invention is beneficial to promoting the growth and development of wheat. It can be used to promote the growth and development of wheat under drought stress, thereby improving the drought resistance of wheat.

[0008] Furthermore, the enzymatic hydrolysis temperature is 45℃~55℃.

[0009] Furthermore, the orange peel extract and seaweed extract are prepared in a volume ratio of 2:5.

[0010] Further, the preparation steps of the orange peel extract are as follows: fresh orange peel is dried and pulverized, 8-10 times its volume of 90%-95% ethanol solution is added, heated to 60℃-65℃, and refluxed for 2.5-3 hours. After solid-liquid separation, the precipitate is collected, and deionized water is added to the precipitate at a material-to-liquid ratio of 1:810. The mixture is heated to 90℃-95℃ for extraction to obtain an aqueous extract. The extract is cooled to 50℃-55℃, the pH is adjusted to 4.0-4.5, and 1%-2% (w / w) of a compound enzyme preparation is added for enzymatic hydrolysis for 2.5-3 hours to obtain an enzyme extract. After passivation treatment, solid-liquid separation is performed, and the clarified liquid is collected and vacuum concentrated at 50℃-55℃ to a concentrate with a soluble solids content of 15%-20%, which is the orange peel extract.

[0011] This invention also provides a method for preparing the aforementioned seaweed organic water-soluble fertilizer, comprising the following steps: Preparation of seaweed extract: Using seaweed as raw material, add water and mix, then add 15%–30% dipotassium hydrogen phosphate and 10%–20% potassium citrate by mass fraction, adjust the pH to 9–11, and extract by intermittent stirring. Then, add 1%–4% alginate lyase, 0.1%–0.5% hupro protease, 0.2%–0.5% neutral protease, 2%–5% cellulase, 1%–3% hemicellulase and 2%–4% ligninase by mass percentage of seaweed for enzymatic extraction, and filter to obtain seaweed extract; The seaweed is composed of *Sargassum fusiforme*, *Sargassum bark* and *Sargassum fusiforme* in a mass ratio of 3-4:1-2:1-2; Preparation of orange peel extract: Fresh orange peel is dried and pulverized, then 8-10 times its volume of 90%-95% ethanol solution is added, heated to 60℃-65℃, and refluxed for 2.5-3 hours. After solid-liquid separation, the precipitate is collected, and deionized water is added to the precipitate at a material-to-liquid ratio of 1:810. The mixture is heated to 90℃-95℃ to obtain an aqueous extract. The extract is cooled to 50℃-55℃, the pH is adjusted to 4.0-4.5, and 1%-2% (w / w) of a compound enzyme preparation is added for enzymatic hydrolysis for 2.5-3 hours to obtain an enzyme extract. After passivation treatment, solid-liquid separation is performed, and the clear liquid is collected and vacuum concentrated at 50℃-55℃ to a concentrate with a soluble solids content of 15%-20%, which is the orange peel extract. Orange peel extract and seaweed extract were mixed at a volume ratio of 2:2 to 5 to obtain seaweed organic water-soluble fertilizer.

[0012] Furthermore, the compound enzyme preparation is prepared by mixing pectinase, cellulase and hemicellulase in a mass ratio of 1:1:1. The present invention also provides the application of the aforementioned seaweed organic water-soluble fertilizer in promoting wheat growth and development, wherein the seaweed organic water-soluble fertilizer is diluted 500 to 1000 times before use.

[0013] Furthermore, the seaweed organic water-soluble fertilizer is used to promote the growth of wheat aboveground plants and roots.

[0014] The present invention also provides the application of the aforementioned seaweed organic water-soluble fertilizer in improving the drought resistance of wheat, wherein the seaweed organic water-soluble fertilizer is diluted 1000 times before use.

[0015] Furthermore, the seaweed organic water-soluble fertilizer is used to improve the survival rate of wheat under drought stress.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The seaweed organic water-soluble fertilizer provided by this invention is rich in natural substances, contains no exogenous chemical synthesis promoters, is green and safe in composition, and has good solubility and rapid dissolution. This seaweed organic water-soluble fertilizer not only promotes the growth and development of wheat's above-ground parts and roots, but also helps alleviate the impact of drought on wheat growth and development under drought stress, thereby improving wheat's drought resistance.

[0017] This invention involves pulverizing a mixture of *Sargassum fusiforme*, *Sargassum barkina*, and *Sargassum fusiforme* to obtain brown algae powder, which is then processed by enzymatic hydrolysis and the addition of orange peel extract to prepare a seaweed organic water-soluble fertilizer. After enzymatic hydrolysis, the main components of the brown algae powder had molecular weights of 208,700 Da (minor), 1,940 Da (major), and 560 Da (major), containing some salts and monosaccharides. This indicates that enzymatic hydrolysis can selectively hydrolyze specific chemical bonds to obtain oligosaccharides and other products within a specific molecular weight range, reducing side reactions and improving solubility and bioavailability. The smaller molecules produced after enzymatic hydrolysis are more easily absorbed. This invention also found that the addition of orange peel extract further promoted the growth and development of wheat plants.

[0018] Compared to existing technologies that create alkaline conditions by adding potassium hydroxide, sodium hydroxide, or potassium carbonate to the system for extraction, although alginic acid is extracted, these media are all strong alkalis, which are highly destructive and thus affect extraction efficiency. This invention, for the first time, selects the milder dipotassium hydrogen phosphate and potassium citrate to create an alkaline environment, reducing damage to active substances; by adding anhydrous citric acid to the extract to adjust the pH to 6, the loss of alkali-insoluble fucoidan is reduced, improving overall utilization and ultimately achieving highly efficient extraction.

[0019] This invention achieves a higher extraction rate and retains more active ingredients from seaweed by combining physical pulverization (airflow ultrafine pulverization), chemical extraction (dipotassium hydrogen phosphate and potassium citrate reaction medium), and compound enzyme extraction.

[0020] Through applied experimental research, this invention shows that both 500-fold and 1000-fold dilutions of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention significantly promote wheat growth and development. The volume ratio of orange peel extract to seaweed extract has a significant impact on the effect; the effects are significantly higher when the volume ratios are 1:1 and 2:5 than when the ratio is 5:2. A volume ratio of 2:5 is optimal. The 1000-fold dilution of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention is beneficial for promoting wheat growth and development, increasing wheat plant height and root length, and improving wheat survival rate under drought stress. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The appearance of the seaweed organic water-soluble fertilizer in Example 1.

[0023] Figure 2 This shows the molecular weight distribution of oligosaccharides during the enzymatic hydrolysis process in Example 1.

[0024] Figure 3 The effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on the aboveground parts of wheat; In the figure, A represents the effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on wheat plant height; B represents the effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on the fresh weight of a single wheat plant.

[0025] Figure 4 The effect of seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on the aboveground parts of wheat; In the figure, A shows the effect of different dilution ratios of the seaweed organic water-soluble fertilizer prepared in Example 1 on the height of wheat plants; B represents the effect of different dilution ratios of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on the fresh weight of a single wheat plant.

[0026] Figure 5 The effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on wheat roots; In the figure, A represents the wheat root phenotype after treatment with different dilution ratios of the seaweed organic water-soluble fertilizer prepared in Example 1; B represents the effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on wheat root length; C represents the effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on wheat root diameter.

[0027] Figure 6 The effects of adding enzymatic hydrolysis of brown algae powder and orange peel extract as excipients on wheat roots; In the figure, A represents the effect of the water-soluble fertilizer prepared in Example 1 and Comparative Examples 1 to 4 on wheat root length; B represents the effect of water-soluble fertilizers prepared in Example 1, Comparative Examples 1 to 4 on wheat root diameter.

[0028] Figure 7 The effects of adding excipients such as enzymatic hydrolysis of brown algae powder and orange peel extract on the aboveground parts of wheat; In the figure, A represents the effect of the water-soluble fertilizer prepared in Example 1 and Comparative Examples 1 to 4 on wheat plant height; B represents the effect of water-soluble fertilizers prepared in Example 1, Comparative Examples 1 to 4 on the fresh weight of individual wheat plants.

[0029] Figure 8 The effect of seaweed organic water-soluble fertilizer prepared in Example 1 on wheat survival rate under drought stress. Detailed Implementation

[0030] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0031] Example 1: A seaweed organic water-soluble fertilizer and its preparation method.

[0032] I. Experimental Materials and Methods 1. Experimental materials Brown algae raw materials: Ascophyllum nodosum, bark algae, Sargassum.

[0033] Enzymes: Alginate lyase (Catalog No.: A1603-100MG; CAS No.: 40591-57-9), purchased from Shanghai Beinuo Biotechnology Co., Ltd. Hupro protease (Specification: 80000U / g) purchased from Wuhan Xinhua Yang Biotechnology Co., Ltd., Jiulong Branch. Neutral protease (Specification: 50000U / g; CAS No.: 9068-59-1), purchased from Weifang Ruichen Biotechnology Co., Ltd.

[0034] Excipient: Orange peel extract.

[0035] 2. Preparation steps (1) Preparation of seaweed extract A composite dried seaweed was prepared by mixing *Sargassum fusiforme*, *Sargassum bark*, and *Sargassum fusiforme* in a mass ratio of 3:1:1. The mixture was then vibrated and sieved to remove impurities, followed by air-jet pulverization to 2000 mesh. The seaweed was transferred to a reaction vessel, and pure water was added at a mass ratio of 1:10. Then, 20% dipotassium hydrogen phosphate and 15% potassium citrate were added according to the mass percentage of the composite dried seaweed to create alkaline reaction conditions and an ion exchange environment. The pH was adjusted to 10 to obtain a mixture. After stirring and dissolving the mixture, the temperature was raised to 75°C. A low-temperature, atmospheric pressure, intermittent stirring extraction was performed for 12 hours, with stirring for 10 minutes followed by 25 minutes of stillness, to obtain a mixed solution. The following reactions occurred during the extraction process: "Calcium alginate + Dipotassium hydrogen phosphate = Calcium phosphate ⬇ + Potassium alginate" and "Calcium alginate + Potassium citrate = Calcium citrate ⬇ + Potassium alginate".

[0036] Anhydrous citric acid was added to the mixture to adjust the pH to 6, and the temperature was lowered to 40℃. 2% alginate lyase was added according to the mass percentage of the compound dried seaweed, and extraction was carried out at 350 rpm for 6 hours while maintaining the temperature. Then, 0.3% hupro protease, 0.5% neutral protease, 3% cellulase, 2% hemicellulase, and 3% ligninase were added sequentially according to the mass percentage of the compound dried seaweed for 4 hours to obtain the extract. The extract was then subjected to a first coarse filtration using a 350-type horizontal decanter centrifuge at 5000 rpm. The filtrate was collected and then subjected to a second filtration using a plate and frame filter. After the second filtration, the filtrate was collected and then subjected to a fine filtration using a tubular centrifuge at 12000 rpm. The filtrate was collected to obtain the seaweed extract.

[0037] (2) Adding auxiliary materials Preparation of orange peel extract: Fresh orange peels were fed into a drum washing machine via an elevator and sprayed with high-pressure water to thoroughly wash away mud, impurities, and some pesticide residues. The washed wet orange peels were then fed into a hammer crusher and crushed into uniform small pieces of about 1 cm².

[0038] The crushed orange peels are fed into a multi-functional extraction tank via a screw conveyor. 90% ethanol is added at a material-to-liquid ratio of 1:8, and the mixture is extracted under reflux at 65°C for 3 hours with thorough stirring. The resulting mixture is then pumped into a filter press for solid-liquid separation. The supernatant and precipitate are collected. The supernatant mainly contains ethanol-soluble substances such as orange peel essential oil, pigments, flavonoids, and fat-soluble vitamins. The precipitate mainly contains cellulose, pectin, some polysaccharides, and proteins. The supernatant is pumped into a vacuum concentrator, where most of the ethanol is evaporated and recovered under high vacuum conditions of 60°C and -0.09 MPa. The recovered ethanol is condensed and then enters a solvent recovery system for reuse after distillation. The supernatant is concentrated to 1 / 15 of its original volume to obtain a concentrated extract. The concentrated extract is then placed in a layered tank with a sight glass. Since the density of orange peel essential oil is less than that of water, it will naturally float to the top and form an oil layer. The crude orange peel essential oil is collected through the outlet at the top of the separator. The collected crude essential oil may contain trace amounts of water and impurities, which can be dehydrated by a molecular sieve. Finally, it is filtered to obtain refined orange peel essential oil, which can be used for other purposes.

[0039] The obtained precipitate was placed in an extraction tank, and deionized water was added at a material-to-liquid ratio of 1:8. The mixture was heated to 95°C and stirred for 2 hours to obtain an aqueous extract. The aqueous extract was cooled to 55°C, and the pH was adjusted to 4.0. A compound enzyme preparation (prepared by mixing pectinase, cellulase, and hemicellulase in a mass ratio of 1:1:1) was added at 1% of the precipitate mass. Enzymatic hydrolysis was performed for 3 hours to obtain an enzyme extract. The enzyme extract was kept at 90°C for 15 minutes to inactivate the enzyme (passivation treatment). Then, solid-liquid separation was performed using a filter press to obtain a clear liquid rich in water-soluble components and a waste residue. The clear liquid was concentrated under vacuum at 55°C to a concentrate with a soluble solids content of 20%, thus obtaining the orange peel extract.

[0040] The obtained orange peel extract and seaweed extract were mixed evenly at a volume ratio of 2:5 and then freeze-dried to obtain seaweed organic water-soluble fertilizer. The product appearance is as follows: Figure 1 As shown.

[0041] The freeze-drying process is as follows: After fine filtration, the collected filtrate is pumped to a special tray in the vacuum drying chamber via a peristaltic pump. Temperature probes are immersed in different layers of freeze-drying trays containing the liquid. Vacuuming is initiated, and when the vacuum level reaches below 10 Pa, it is maintained for 15 minutes to end the pre-freezing and begin the sublimation stage. Sublimation is divided into 5 stages, with temperatures controlled at -15℃, -10℃, -5℃, -3℃, and 0℃ respectively. Based on the frost formation in the cold trap, it is roughly determined that the water content has sublimated to over 90%, and desorption drying begins. The first stage of desorption drying involves slow heating for 1 hour, until the fluid temperature reaches 25℃ and the dry algae powder product temperature reaches above 14℃. The second stage involves rapid heating, controlling the fluid temperature at approximately 25℃ for about 6 hours. The freeze-drying operation ends when the dry algae powder temperature approaches the fluid temperature. The diaphragm valve in the freeze-drying chamber is closed, and the air inlet valve is opened to introduce sterile air into the freeze-drying chamber and cold trap. Once the air pressure inside the freeze-drying chamber reaches one atmosphere, the chamber door can be opened to remove the freeze-dried powder, which is seaweed organic water-soluble fertilizer.

[0042] I. Characterization of seaweed organic water-soluble fertilizer and related products obtained in Example 1 After enzymatic hydrolysis of brown algae powder, the enzymatic hydrolysis products were sent to the Qingdao Marine Biomedical Research Institute Testing Center for testing to analyze the molecular weight distribution of oligosaccharides in the enzymatically hydrolyzed brown algae powder.

[0043] The results are as follows Figure 2 As shown, the molecular weights of the main components of the sample to be tested are 208700 Da (small amount), 1940 Da (main), and 560 Da (main), respectively, and it contains some salt and monosaccharide components.

[0044] The water solubility of the seaweed organic water-soluble fertilizer prepared in Example 1 was tested. The specific steps were as follows: Place an appropriate amount of water-soluble fertilizer sample in a clean container, ensuring the sample is free of lumps or moisture. Add the sample to deionized water at a material-to-liquid ratio of 1g:30mL, and stir thoroughly until completely dissolved. Observe the dissolution rate and whether any undissolved particles appear. After standing for 5 minutes, check the transparency of the solution.

[0045] like Figure 3 As shown, the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention produces a large number of microbubbles during dissolution, which improves wetting and dispersion efficiency, and accelerates dissolution; it solves the problems of slow water dissolution, secondary dilution, and clumping of traditional products. The seaweed organic water-soluble fertilizer prepared in Example 1 of this invention has no suspended matter or sediment. The seaweed organic water-soluble fertilizer prepared by this invention dissolves completely within 5 minutes, which is short and rapid.

[0046] Example 2: A seaweed organic water-soluble fertilizer and its preparation method.

[0047] The remaining steps are the same as in Example 1, except that: The mass ratio of the algae, bark algae, and sargassum is 3:2:2.

[0048] Example 3: A seaweed organic water-soluble fertilizer and its preparation method.

[0049] The remaining steps are the same as in Example 1, except that: The mass ratio of *Sargassum fusiforme*, *Sargassum bark*, and *Sargassum fusiforme* is 4:1:1.

[0050] Example 4: A seaweed organic water-soluble fertilizer and its preparation method.

[0051] The remaining steps are the same as in Example 1, except that: The mass ratio of *Sargassum fusiforme*, *Sargassum bark*, and *Sargassum fusiforme* is 4:2:2.

[0052] Example 5: A seaweed organic water-soluble fertilizer and its preparation method.

[0053] The remaining steps are the same as in Example 1, except that: The compound enzyme preparation is obtained by mixing alginate lyase, hupro protease and neutral protease in a mass ratio of 3:1:1.

[0054] Comparative Example 1: A seaweed fertilizer and its preparation method.

[0055] The compound dried seaweed was prepared by mixing seaweed, bark seaweed and Sargassum in a mass ratio of 3:1:1. The mixture was then sieved to remove impurities and pulverized to 2000 mesh by airflow to obtain brown algae powder. The brown algae powder was dissolved by adding water, heating and stirring to obtain a 1000-fold diluted solution, which was recorded as 1000-fold comparative example 1.

[0056] Comparative Example 2: A seaweed organic water-soluble fertilizer and its preparation method.

[0057] Brown algae oligosaccharide powder was prepared directly from the seaweed extract of Example 1 using the freeze-drying step in Example 1, and used as the seaweed organic water-soluble fertilizer of Comparative Example 2. A 1000-fold dilution is designated as Comparative Example 2.

[0058] Comparative Example 3: A seaweed organic water-soluble fertilizer and its preparation method.

[0059] The method of Comparative Example 3 is basically the same as that of Example 1, except that the mass ratio of orange peel extract to seaweed extract is 5:2. The 1000-fold dilution is recorded as Comparative Example 3.

[0060] Comparative Example 4: A seaweed organic water-soluble fertilizer and its preparation method.

[0061] The method of Comparative Example 4 is basically the same as that of Example 1, except that the mass ratio of orange peel extract to seaweed extract is 1:1. The 1000-fold dilution is recorded as Comparative Example 4.

[0062] Comparative Example 5: A seaweed organic water-soluble fertilizer and its preparation method.

[0063] Comparative Example 5 follows the same basic steps as Example 1, except that: Remove the alginate lyase used for enzymatic hydrolysis during the enzymatic hydrolysis process.

[0064] The seaweed organic water-soluble fertilizer prepared in Comparative Example 5 was tested for water solubility using the same method as that used in Example 1. The results showed that the seaweed organic water-soluble fertilizer prepared in Comparative Example 5 required half an hour to dissolve, and a precipitate formed in the solution after dissolution. This indicates that the compound enzyme preparation in this invention promotes the dissolution of the brown algae powder through enzymatic hydrolysis, thereby increasing the dissolution rate of the seaweed organic water-soluble fertilizer.

[0065] Seaweed organic water-soluble fertilizers were prepared according to the above examples and comparative examples. These seaweed organic water-soluble fertilizers were then used in studies on wheat growth and development and wheat drought resistance. See the following application examples for details.

[0066] Application Example 1: The effects of seaweed organic water-soluble fertilizers prepared by different methods on wheat growth and development.

[0067] 1. Experimental material: wheat seeds Shannong 28.

[0068] 2. Experimental Design: The seaweed organic water-soluble fertilizer prepared in Example 1 was diluted by 500 times, 1000 times, 1500 times and 2000 times to obtain seaweed organic water-soluble fertilizer dilutions of different ratios, which were recorded as 500 times Example 1, 1000 times Example 1, 1500 times Example 1 and 2000 times Example 1, respectively.

[0069] The seaweed organic water-soluble fertilizers prepared in Comparative Examples 1, 2, 3, and 4 were diluted 1000 times to obtain the diluted solutions, which were then designated as 1000x Comparative Example 1, 1000x Comparative Example 2, 1000x Comparative Example 3, and 1000x Comparative Example 4, respectively. Water was used as a blank control.

[0070] Zhongke Glory 1000-fold dilution was used as a positive control: 1.5 g of Zhongke Glory 90% chitosan oligosaccharide powder was added to 100 mL of 35℃ warm water while stirring until completely dissolved. Then it was diluted 1000 times.

[0071] 3. Experimental Treatment: Wheat seeds were soaked in the respective experimental agents for germination. After germination, they were hydroponically treated in the same experimental agents. After 15 days, the wheat plant height, single-plant fresh weight, root length, and root diameter were observed. The specific testing methods are as follows;

[0072] (1) Plant height: Select one bottle of wheat with better growth for each treatment group, select 8 wheat plants with the same growth, measure the plant height of the wheat plants with a ruler, and calculate the average value.

[0073] (2) Root length and root thickness: For each treatment group, select one bottle of wheat with better growth and select 8 wheat plants with the same growth to measure the root length of the wheat using a root scanner and root phenotyping system.

[0074] (3) Fresh weight of aboveground parts: Select one bottle of wheat with better growth for each treatment group, select wheat with consistent growth, cut off the roots with scissors, wipe the water off the surface of the aboveground parts, and select the group with better growth to measure the weight with an electronic balance.

[0075] 4. Effects of different dilution ratios of the seaweed organic water-soluble fertilizer prepared in Example 1 on wheat growth and development. The effects of 500x, 1000x, 1500x and 2000x Examples 1 on wheat growth and development were compared.

[0076] The results are as follows Figure 4 As shown, the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention is beneficial to increasing wheat plant height and fresh weight. The 1000-fold dilution of the seaweed organic water-soluble fertilizer prepared in Example 1 showed the most significant effect, significantly higher than the water group and other dilutions.

[0077] like Figure 5 As shown, the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention is beneficial to the growth of wheat roots. Both the 1000-fold and 500-fold dilutions of the seaweed organic water-soluble fertilizer prepared in Example 1 significantly increased the root length of wheat.

[0078] 5. Effects of enzymatic hydrolysis of brown algae powder and the addition of orange peel extract as excipients on wheat growth and development. (1) Comparative Study: The effects of 1000-fold dilution of seaweed organic water-soluble fertilizer prepared in Example 1 and 1000-fold dilution of seaweed organic water-soluble fertilizer prepared in Comparative Examples 1, 2, 3 and 4 on the growth and development of wheat roots.

[0079] like Figure 6 As shown in the figure, the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention has a significantly higher effect on promoting the root growth of wheat than the brown algae powder in Comparative Example 1 and the brown algae oligosaccharide powder in Comparative Example 2. It can be seen from the figure that enzymatic hydrolysis can improve the growth-promoting effect on wheat, and the further addition of the excipient orange peel extract significantly improves the product's effect on wheat root growth. However, comparative analysis between Example 1, Comparative Example 3, and Comparative Example 4 revealed that the volume ratio of orange peel extract to seaweed extract has a certain influence on its effect. It was found that the effect was significantly higher when the volume ratio of orange peel extract to seaweed extract was 1:1 and 2:5 than when it was 5:2. A volume ratio of 2:5 for orange peel extract to seaweed extract is optimal.

[0080] (2) Compare the effects of the 1000-fold dilution of seaweed organic water-soluble fertilizer prepared in Example 1 and the 1000-fold dilution of seaweed organic water-soluble fertilizer prepared in Comparative Examples 1, 2, 3 and 4 on the aboveground growth and development of wheat.

[0081] like Figure 7 As shown in the figure, the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention has a significantly higher growth-promoting effect on the aboveground parts of wheat than the brown algae powder in Comparative Example 1 and the brown algae oligosaccharide powder in Comparative Example 2. It can be seen from the figure that enzymatic hydrolysis of brown algae powder can improve its growth-promoting effect on wheat, and the further addition of the excipient orange peel extract significantly improves the product's growth-promoting effect on the aboveground parts of wheat. However, comparative analysis between Example 1, Comparative Example 3, and Comparative Example 4 revealed that the volume ratio of orange peel extract to seaweed extract has a certain influence on its effect. It was found that the volume ratios of orange peel extract to seaweed extract of 1:1 and 2:5 were significantly more effective than 5:2. A volume ratio of 2:5 for orange peel extract to seaweed extract is optimal.

[0082] Application Example 2: The effect of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention on the drought resistance of wheat.

[0083] I. Experimental Methods Using Shannong 28 wheat seeds as the experimental variety, wheat seeds were soaked in a 1000-fold dilution of the seaweed organic water-soluble fertilizer prepared in Example 1 for germination, serving as the experimental group. Seeds germinated in plain water served as the control group. The control group was further divided into two subgroups: one without drought treatment (normal control group) and the other with drying treatment (drought control group). After germination, the seeds were transplanted into a substrate (volume ratio: vermiculite:perlite:coconut coir = 4:3:3) for pot experiments, with 3 seedlings per pot. Each treatment group had 15 seedlings.

[0084] Drought simulation treatment: During hydroponic cultivation, PEG6000 at a mass fraction of 20% was applied for simulation. The plants were irrigated with PEG6000 at a mass fraction of 20% every two days for 12 consecutive days. Wheat growth and development were observed after 15 days of cultivation. The control group received no drought simulation and served as a blank control.

[0085] Survival rates were calculated using the following formula: Survival rate = (N) t -N d ) / N t ; In the formula, N d For the plants that did not survive, N t The total number of plants tested.

[0086] N dThe criteria for judgment are as follows: if the entire plant turns yellow and withers, with the top of the above-ground parts drooping and lodging, it is recorded as a plant N that failed to survive the drought treatment. d If the entire plant remains upright, with only some leaves wilting above ground and no lodging, and the whole plant still appears green, it is recorded as a plant that survived the drought treatment.

[0087] II. Experimental Results The results are as follows Figure 8 As shown, compared to the normal control group without drought simulation, wheat plants germinated with water had a significantly lower survival rate under drought stress. However, wheat plants germinated by soaking in a 1000-fold dilution of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention significantly alleviated the effects of drought stress, and their survival rate was significantly higher than that of the drought control group. This indicates that the 1000-fold dilution of the seaweed organic water-soluble fertilizer prepared in Example 1 of this invention is beneficial for improving the drought resistance of wheat.

[0088] It should be noted that all water-soluble fertilizers in this invention are diluted using water as the solvent.

[0089] Although preferred embodiments of the invention have been described, those skilled in the art, once they have learned the basic inventive concept, can make other changes and modifications to these embodiments.

[0090] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A seaweed organic water-soluble fertilizer, characterized in that, The seaweed organic water-soluble fertilizer is prepared by freeze-drying a mixture of orange peel extract and seaweed extract at a volume ratio of 2:2-5. The orange peel extract is obtained by extracting fresh orange peel with alcohol, separating solid and liquid, collecting the precipitate, extracting the precipitate with water, adding a compound enzyme preparation for enzymatic hydrolysis to obtain an enzyme extract, separating solid and liquid, collecting the clear liquid, and concentrating it under vacuum. The seaweed extract is prepared by the following steps: using seaweed as raw material, water is added and mixed, followed by the addition of 15%–30% by mass of dipotassium hydrogen phosphate and 10%–20% by mass of potassium citrate. The pH is adjusted to 9–11, and the seaweed is extracted by intermittent stirring. Then, according to the seaweed mass percentage, 1%–4% alginate lyase, 0.1%–0.5% hupro protease, 0.2%–0.5% neutral protease, 2%–5% cellulase, 1%–3% hemicellulase, and 2%–4% ligninase are added sequentially for enzymatic extraction. The seaweed extract is obtained by filtration. The seaweed is composed of *Sargassum fusiforme*, *Sargassum bark*, and *Sargassum fusiforme* in a mass ratio of 3–4:1–2:1–2.

2. The seaweed organic water-soluble fertilizer according to claim 1, characterized in that, The enzymatic hydrolysis temperature is 45℃~55℃.

3. The seaweed organic water-soluble fertilizer according to claim 1, characterized in that, The orange peel extract and seaweed extract are mixed at a volume ratio of 2:

5.

4. The seaweed organic water-soluble fertilizer according to claim 1, characterized in that, The preparation steps of the orange peel extract are as follows: Fresh orange peel is dried and pulverized, then 8-10 times its volume of 90%-95% ethanol solution is added, heated to 60℃-65℃, and refluxed for 2.5-3 hours. After solid-liquid separation, the precipitate is collected, and deionized water is added to the precipitate at a material-to-liquid ratio of 1:

810. The mixture is heated to 90℃-95℃ for extraction to obtain an aqueous extract. The extract is cooled to 50℃-55℃, the pH is adjusted to 4.0-4.5, and 1%-2% (w / w) of a compound enzyme preparation is added for enzymatic hydrolysis for 2.5-3 hours to obtain an enzyme extract. After passivation treatment, solid-liquid separation is performed, and the clarified liquid is collected and vacuum concentrated at 50℃-55℃ to a concentrate with a soluble solids content of 15%-20%, which is the orange peel extract.

5. A method for preparing the seaweed organic water-soluble fertilizer according to any one of claims 1 to 4, characterized in that, Includes the following steps: Preparation of seaweed extract: Using seaweed as raw material, add water and mix, then add 15%–30% dipotassium hydrogen phosphate and 10%–20% potassium citrate by mass fraction, adjust the pH to 9–11, and extract by intermittent stirring. Then, add 1%–4% alginate lyase, 0.1%–0.5% hupro protease, 0.2%–0.5% neutral protease, 2%–5% cellulase, 1%–3% hemicellulase and 2%–4% ligninase by mass percentage of seaweed for enzymatic extraction, and filter to obtain seaweed extract; The seaweed is composed of *Sargassum fusiforme*, *Sargassum bark* and *Sargassum fusiforme* in a mass ratio of 3-4:1-2:1-2; Preparation of orange peel extract: Fresh orange peel is dried and pulverized, then 8-10 times its volume of 90%-95% ethanol solution is added, heated to 60℃-65℃, and refluxed for 2.5-3 hours. After solid-liquid separation, the precipitate is collected, and deionized water is added to the precipitate at a material-to-liquid ratio of 1:

810. The mixture is heated to 90℃-95℃ to obtain an aqueous extract. The extract is cooled to 50℃-55℃, the pH is adjusted to 4.0-4.5, and 1%-2% (w / w) of a compound enzyme preparation is added for enzymatic hydrolysis for 2.5-3 hours to obtain an enzyme extract. After passivation treatment, solid-liquid separation is performed, and the clear liquid is collected and vacuum concentrated at 50℃-55℃ to a concentrate with a soluble solids content of 15%-20%, which is the orange peel extract. Orange peel extract and seaweed extract were mixed at a volume ratio of 2:2-5 and then freeze-dried to obtain seaweed organic water-soluble fertilizer.

6. The method for preparing seaweed organic water-soluble fertilizer according to claim 5, characterized in that, The compound enzyme preparation is prepared by mixing pectinase, cellulase and hemicellulase in a mass ratio of 1:1:

1.

7. The application of the seaweed organic water-soluble fertilizer according to any one of claims 1 to 5 in promoting wheat growth and development, characterized in that, The seaweed organic water-soluble fertilizer should be diluted 500 to 1000 times before use.

8. The application according to claim 7, characterized in that, The seaweed organic water-soluble fertilizer is used to promote the growth of wheat above-ground plants and roots.

9. The application of the seaweed organic water-soluble fertilizer according to any one of claims 1 to 5 in improving the drought resistance of wheat, characterized in that, The seaweed organic water-soluble fertilizer is diluted 1000 times before use.

10. The application according to claim 9, characterized in that, The seaweed organic water-soluble fertilizer is used to improve the survival rate of wheat under drought stress.

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