Composite microbial bacteria-decomposing seaweed fertilizer, preparation method and application thereof

Abstract

The present application relates to the technical field of algal fertilizer preparation, and more particularly to a compound microbial bacteria-degraded seaweed fertilizer, a preparation method and application thereof.The compound microbial bacteria-degraded seaweed fertilizer comprises seaweed fermentation degradation products, humic acid, amino acid powder, trace element additives and molasses; the seaweed fermentation degradation products are degradation liquid obtained by filtering after fermentation and degradation of seaweed raw materials by at least two kinds of compound microbial agents including Bacillus pumilus BNCC103925, Bacillus tequilensis BNCC357969, Vibrio alginolyticus BNCC381281 and Pseudomonas stutzeri BNCC136904. Four specific functional strains with synergistic degradation activity of seaweed are obtained by screening, and the seaweed degradation products prepared by compound fermentation thereof are used as the core, and are combined with amino acid powder and humic acid to form a synergistic system, thereby greatly improving the yield and quality of crops.

Description

Technical Field

[0001] This invention relates to the field of algae fertilizer technology, and more specifically, to compound microbial hydrolyzed seaweed fertilizer, its preparation method and application. Background Technology

[0002] Seaweed is one of the most important biological resources in the ocean, containing abundant nutrients and bioactive components. Seaweed contains polysaccharides (such as alginate and fucoidan), proteins, amino acids, vitamins, minerals, and plant growth regulators (such as gibberellins, indoleacetic acid, and cytokinins). These components have significant effects on promoting plant growth, enhancing crop resistance, and improving soil structure. In recent years, seaweed fertilizers, due to their natural, efficient, and environmentally friendly characteristics, have become a research hotspot and an important development direction in the field of new fertilizers.

[0003] Currently, the preparation methods for seaweed fertilizer mainly fall into three categories: physical methods, chemical methods, and biological methods. Physical methods, such as mechanical crushing and ultrasonic treatment, are simple to operate, but their cell wall disruption efficiency is limited, resulting in insufficient release of active ingredients from the seaweed. Chemical methods primarily use strong alkalis (such as potassium hydroxide and sodium hydroxide) to hydrolyze seaweed under high temperature and pressure conditions. While this method can relatively thoroughly degrade the macromolecules of seaweed, the strong alkali and high temperature conditions severely damage the natural active ingredients in the seaweed (such as plant hormones and vitamins), and the use of chemical reagents causes environmental pollution, which does not meet the requirements of green agriculture development.

[0004] Biological methods are mainly divided into enzymatic hydrolysis and microbial degradation (bacterial hydrolysis). Enzymatic hydrolysis utilizes complex enzyme systems such as alginate lyase, cellulase, and pectinase to degrade seaweed cell walls and release intracellular active substances. However, enzyme preparations are expensive, and the hydrolysis conditions are quite demanding, limiting its industrial application. Microbial degradation (bacterial hydrolysis) utilizes strains of microorganisms with seaweed-degrading capabilities. Under mild conditions, enzyme systems produced by microbial metabolism (such as alginate lyase, cellulase, and protease) degrade seaweed cell walls, allowing for the complete release of the seaweed's active ingredients. Bacterial hydrolysis has significant advantages such as mild conditions, simple equipment, complete preservation of active ingredients, and low cost.

[0005] However, existing bacterial decomposition seaweed fertilizer technology still has the following shortcomings: (1) Most of the reported seaweed-degrading strains have limited degradation efficiency. The enzyme system produced by a single strain is limited and it is difficult to completely degrade the complex polysaccharide structure (algin, cellulose, hemicellulose, etc.) in the seaweed cell wall, resulting in insufficient release of seaweed effective components.

[0006] (2) The types of metabolites produced during the fermentation of a single strain are limited, making it difficult to produce a variety of plant growth-promoting active substances. The biological activity and fertilizer efficiency of seaweed fertilizer need to be further improved.

[0007] (3) The existing combination of microbial agents lacks systematic research on synergistic effects, the interaction mechanism between strains is unclear, and the seaweed degradation efficiency and the diversity of active substances in the products need to be optimized.

[0008] (4) The preparation process of partially hydrolyzed seaweed fertilizer is complex, the fermentation cycle is long and the cost is high, which is not conducive to large-scale production and practical application.

[0009] Therefore, developing a compound microbial biodegradation seaweed fertilizer with a reasonable combination of strains, high seaweed degradation efficiency, rich active substances, and simple preparation process is of great significance for realizing the high-value utilization of seaweed resources and promoting the sustainable development of green agriculture. Summary of the Invention

[0010] In view of this, the purpose of this invention is to at least partially solve one of the technical problems in the above-mentioned related technologies. To this end, this invention provides a compound microbial biodegradable seaweed fertilizer, its preparation method, and its application.

[0011] The first aspect of this invention provides a compound microbial biodegradable seaweed fertilizer, which is composed of the following components in parts by weight: 40-70 parts seaweed fermentation degradation product, 5-20 parts humic acid, 3-15 parts amino acid powder, 1-8 parts trace element additives, and 2-10 parts molasses; The seaweed fermentation degradation product is a degradation liquid obtained by fermenting and degrading seaweed raw materials with at least two of the following compound microbial agents: Bacillus pumilus BNCC103925, Bacillus tequilensis BNCC357969, Vibrio alginolyticus BNCC381281, and Pseudomonas stutzeri BNCC136904, and then filtering the product.

[0012] Furthermore, the compound microbial agent contains two strains: Bacillus pumilus BNCC103925 and Pseudomonas schrenckii BNCC136904.

[0013] Furthermore, the compound microbial agent contains three strains: Vibrio alginolyticus BNCC381281, Bacillus pumilus BNCC103925, and Bacillus tekirae BNCC357969.

[0014] Furthermore, the trace element additive comprises the following components in parts by weight: 0.5-2 parts zinc sulfate, 0.5-2 parts boric acid, 0.5-1.5 parts manganese sulfate, and 0.1-0.5 parts ammonium molybdate.

[0015] Furthermore, the seaweed raw material is selected from one or more of the following: giant kelp, kelp, Sargassum, bubbly seaweed, sea lettuce, bristle algae, and filamentous algae.

[0016] Furthermore, the seaweed fertilizer is either liquid or solid.

[0017] Secondly, the present invention provides a method for preparing the aforementioned compound microbial hydrolyzed seaweed fertilizer, comprising the following steps: (1) Dry and pulverize the seaweed raw material to obtain seaweed powder; (2) Bacillus pumilus BNCC103925, Bacillus tekira BNCC357969, Vibrio alginolyticus BNCC381281 and Pseudomonas schrenckii BNCC136904 were respectively inoculated into LB liquid medium for activation and expansion. (3) Mix the various strains after expansion culture in proportion and inoculate them into seaweed fermentation culture medium for fermentation and degradation. Collect the fermentation liquid, filter it, and obtain seaweed fermentation degradation product. (4) Mix the seaweed fermentation degradation product obtained in step (3) with humic acid, amino acid powder, trace element additives and molasses in the specified weight proportions to obtain liquid bacterial hydrolyzed seaweed fertilizer; or dry the mixture to obtain solid bacterial hydrolyzed seaweed fertilizer.

[0018] Thirdly, this invention provides the application of the compound microbial hydrolyzed seaweed fertilizer in promoting plant growth, increasing crop yield and quality, and improving soil.

[0019] In summary, the present invention achieves at least the following technical effects: 1. This invention screened and obtained a specific functional strain combination with highly efficient seaweed degradation activity. When used alone, the four strains—Bacillus pumilus BNCC103925, Bacillus tekirae BNCC357969, Vibrio alginolyticus BNCC381281, and Pseudomonas schlegelii BNCC136904—achieved seaweed degradation rates of 22.53%, 19.60%, 25.07%, and 29.07% respectively on kelp powder and South African giant kelp powder after 7 days. Among them, the combined use of Vibrio alginolyticus BNCC381281 and Pseudomonas schlegelii BNCC136904 resulted in a seaweed degradation rate of 37.8% after 7 days (Example 3), significantly better than the effects of any single strain. Comparative Examples 2 and 3 show that replacing Bacillus pumilus BNCC103925 with Bacillus subtilis BNCC109047, or replacing Vibrio alginolyticus BNCC381281 with Vibrio alginolyticus BNCC337013, significantly reduced the seaweed degradation efficiency and tomato yield. This indicates that the specific strain combination obtained by screening in this invention has a non-obvious synergistic degradation function, and the same effect cannot be achieved by simply replacing similar strains.

[0020] 2. This invention constructs a ternary synergistic system of "specific strains degrading seaweed + amino acid powder + humic acid," none of which can be omitted. Seaweed must be fermented and degraded by the specific strains selected in this invention to fully release its active ingredients. The amino acid powder not only provides a readily available organic nitrogen source, but its carboxyl and amino groups can also form stable molecular complexes with polyphenols, polysaccharides, and other active ingredients in the seaweed degradation products through hydrogen bonding, effectively protecting the seaweed's active ingredients and extending its fertilizer effect. The quinone and phenolic hydroxyl groups in humic acid interact with polysaccharides, proteins, and other components in the seaweed degradation products through non-covalent interactions to form supramolecular aggregates, synergistically improving soil aggregate structure and providing adsorption and slow-release functions for the seaweed's active ingredients. These three components form a complete system with novel functions through physicochemical mechanisms such as intermolecular hydrogen bonding, hydrophobic interactions, and complexation reactions. In Comparative Example 1, after replacing amino acid powder and humic acid in equal amounts with seaweed fermentation degradation products, the yield per plant decreased from 2094.8g to 1425.2g, a decrease of 47.0%, which fully demonstrates that amino acid powder and humic acid are the key synergistic components in the formula of this invention, and the omission of either one leads to a significant decrease in fertilizer efficiency.

[0021] 3. This invention achieves a synergistic improvement in both yield and quality of seaweed fertilizer. Tomato pot experiment results show that the yield per plant in the treatment group treated with the compound microbial hydrolyzed seaweed fertilizer prepared in Example 3 of this invention reached 2094.8g, an increase of 112.8% compared to the blank control (984.4g), and increases of 47.0%, 30.1%, and 36.2% compared to Comparative Examples 1, 2, and 3, respectively. Simultaneously, the fruit's vitamin C content reached 23.6mg / 100g, soluble sugar content reached 4.85%, and soluble protein content reached 7.03mg / g, increases of 40.5%, 41.8%, and 44.7% compared to the blank control, respectively, achieving a synergistic improvement in both yield and quality. In Example 3, the tomato plant height, stem diameter, SPAD value, aboveground fresh weight, and underground fresh weight of the treated tomato plants increased by 46.8%, 39.7%, 30.4%, 69.2%, and 77.8% respectively compared with the control (CK). The root activity also increased by 89.7% compared with the control. This indicates that the seaweed fertilizer of the present invention not only promotes the growth of the aboveground parts but also has a positive effect on root development, which is conducive to the establishment of a good root-crown coordinated growth relationship in crops.

[0022] 4. The preparation process of this invention is simple, environmentally friendly, and easy to industrialize. This invention uses microbial fermentation to replace the traditional strong alkali high-temperature hydrolysis method, completing the degradation of seaweed under mild conditions. This completely avoids the destruction of the natural active ingredients in seaweed by strong alkali and high temperature, produces no harmful byproducts, and causes no secondary pollution to water and soil environments. The beneficial microorganisms in the product can further colonize and reproduce after being applied to the soil, continuously exerting functions such as degrading organic matter and releasing nutrients, resulting in a long-term positive effect on improving soil ecology. The preparation process uses conventional culture media for strain activation and expansion. The fermentation conditions are mild, equipment requirements are low, operation is simple, and costs are low, making it easy to achieve large-scale production and possessing good industrialization prospects and market competitive advantages. Detailed Implementation

[0023] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges or individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0026] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0027] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0028] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0029] All raw materials used in the examples are commercially available.

[0030] All bacterial strains used in the examples were purchased from Beina Biotechnology.

[0031] Example 1

[0032] This embodiment provides a compound microbial hydrolyzed seaweed liquid fertilizer, which is composed of the following components in parts by weight: 40 parts of seaweed fermentation degradation product, 5 parts of humic acid, 3 parts of amino acid powder, 1 part of trace element additive, and 2 parts of molasses; The seaweed fermentation degradation product is a degradation liquid obtained by fermenting and degrading seaweed raw materials using two strains: Bacillus pumilus BNCC103925 and Pseudomonas schlegelii BNCC136904, followed by filtration; the degradation rate of seaweed raw materials reached 35.2% after 7 days. The trace element additive contains the following components in parts by weight: 0.5 parts zinc sulfate, 0.5 parts boric acid, 0.5 parts manganese sulfate, and 0.1 parts ammonium molybdate; The seaweed raw material is selected from South African giant kelp.

[0033] The preparation method of the above-mentioned compound microbial decomposed seaweed liquid fertilizer includes the following steps: (1) Dry and pulverize the seaweed raw material to obtain seaweed powder; (2) Bacillus pumilus BNCC103925 and Pseudomonas schwannii BNCC136904 were inoculated into LB liquid medium for activation and amplification until the effective viable count was 1.5 × 10⁻⁶. 8 ~1.2×10 10 CFU / mL; (3) Mix the various bacterial cultures after expansion at a volume ratio of 1:4 and inoculate them into the seaweed fermentation medium for fermentation and degradation. Ferment at 30℃ for 40 days, collect the fermentation liquid, filter it, and obtain the seaweed fermentation degradation product. (4) Mix the seaweed fermentation degradation product obtained in step (3) with humic acid, amino acid powder, trace element additives and molasses according to the weight parts to obtain liquid bacterial hydrolyzed seaweed fertilizer.

[0034] Example 2

[0035] This embodiment provides a compound microbial hydrolyzed seaweed liquid fertilizer, which is composed of the following components in parts by weight: 70 parts seaweed fermentation degradation product, 20 parts humic acid, 15 parts amino acid powder, 8 parts trace element additives, and 10 parts molasses; The seaweed fermentation degradation product is a degradation liquid obtained by fermenting and degrading seaweed raw materials with a microbial agent containing three strains of Vibrio alginolyticus BNCC381281, Bacillus pumilus BNCC103925, and Bacillus tekirae BNCC357969, and then filtering the solution; the degradation rate of seaweed raw materials reached 31.5% after 7 days. The trace element additive contains the following components in parts by weight: 2 parts zinc sulfate, 2 parts boric acid, 1.5 parts manganese sulfate, and 0.5 parts ammonium molybdate; The seaweed raw material is selected from Sargassum.

[0036] The preparation method of the above-mentioned compound microbial decomposed seaweed liquid fertilizer includes the following steps: (1) Dry and pulverize the seaweed raw material to obtain seaweed powder; (2) Bacillus pumilus BNCC103925, Bacillus tekirae BNCC357969, Vibrio alginolyticus BNCC381281, and Pseudomonas schrenckii BNCC136904 were inoculated into LB liquid medium for activation and amplification until the effective viable count was 1.5 × 10⁻⁶. 8 ~1.2×10 10 CFU / mL; (3) Mix the various bacterial cultures after expansion culture at a volume ratio of 1:1.5:2 and inoculate them into the seaweed fermentation medium for fermentation and degradation. Ferment at 30℃ for 40 days, collect the fermentation liquid, filter it, and obtain the seaweed fermentation degradation product. (4) Mix the seaweed fermentation degradation product obtained in step (3) with humic acid, amino acid powder, trace element additives and molasses according to the weight parts to obtain liquid bacterial hydrolyzed seaweed fertilizer.

[0037] Example 3

[0038] This embodiment provides a compound microbial hydrolyzed seaweed liquid fertilizer, which is composed of the following components in parts by weight: 55 parts of seaweed fermentation degradation product, 12 parts of humic acid, 8 parts of amino acid powder, 5 parts of trace element additives, and 7 parts of molasses; The seaweed fermentation degradation product is a degradation liquid obtained by fermenting and degrading seaweed raw materials with a microbial agent containing Vibrio alginolyticus BNCC381281 and Pseudomonas stutzeri, followed by filtration; the degradation rate of seaweed raw materials reached 37.8% after 7 days. The trace element additive contains the following components in parts by weight: zinc sulfate 0.5-2 parts, boric acid 0.5-2 parts, manganese sulfate 0.5-1.5 parts, and ammonium molybdate 0.1-0.5 parts; The seaweed raw material is *Alternaria latifolia*.

[0039] The preparation method of the above-mentioned compound microbial decomposed seaweed liquid fertilizer includes the following steps: (1) Dry and pulverize the seaweed raw material to obtain seaweed powder; (2) Bacillus pumilus BNCC103925, Bacillus tekira BNCC357969, Vibrio alginolyticus BNCC381281 and Pseudomonas schrenckii BNCC136904 were respectively inoculated into LB liquid medium for activation and expansion. (3) Mix the expanded bacterial cultures in a volume ratio of 1:1.5:2:5 and inoculate them into the seaweed fermentation medium for fermentation and degradation. Ferment at 32℃ for 50 days, collect the fermentation liquid, filter it, and obtain the seaweed fermentation degradation product. (4) Mix the seaweed fermentation degradation product obtained in step (3) with humic acid, amino acid powder, trace element additives and molasses according to the weight parts to obtain liquid bacterial hydrolyzed seaweed fertilizer.

[0040] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that the amino acid powder was replaced with an equal amount of seaweed fermentation degradation product.

[0041] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that Bacillus pumilus BNCC103925 was replaced with Bacillus subtilis BNCC109047 (purchased from Beina Biotechnology).

[0042] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that Vibrio alginolyticus BNCC381281 was replaced with Vibrio alginolyticus BNCC337013 (purchased from Beina Biotechnology).

[0043] Example 4

[0044] Liquid fertilizers were prepared from fish protein hydrolysates prepared in Example 1 and Comparative Examples 1 to 3 and then tested in pots.

[0045] Tomato pot experiment Test materials The tomato variety used in the experiment was "Xinzhongshu No. 4" (Solanum lycopersicum L.). Plump, uniformly sized seeds were selected, soaked in 55℃ warm water for 15 minutes, and then germinated at 28℃ before being sown in seedling trays. When the seedlings had 3-4 true leaves, healthy, uniformly growing seedlings were transplanted into plastic flowerpots (25 cm in diameter and 20 cm in height). The cultivation substrate was peat moss:vermiculite:perlite = 3:1:1 (volume ratio), with 3.5 kg of substrate per pot and one plant per pot. The experiment was conducted in a greenhouse under natural light, with daytime temperatures controlled at 25-30℃ and nighttime temperatures at 18-22℃, and relative humidity at 60%-70%.

[0046] Experimental Design The experiment consisted of 6 treatments: CK: Watered with an equal amount of clean water (blank control); Liquid fertilizer 2: Apply the liquid fertilizer prepared in Comparative Example 1 by watering; Liquid fertilizer 3: Apply the liquid fertilizer prepared in Comparative Example 2 by watering; Liquid fertilizer 4: Apply the liquid fertilizer prepared in Comparative Example 3 by watering; Liquid fertilizer 1: Apply the liquid fertilizer prepared in Example 3 (this invention) by watering.

[0047] Each treatment was repeated 3 times (3 pots per replicate, 1 plant per pot), for a total of 54 pots, arranged in a randomized block. All pots were placed randomly in the greenhouse and their positions were rotated periodically to reduce edge effects.

[0048] All liquid fertilizers were diluted 100 times (by volume) with water before use, shaken thoroughly, and applied immediately. The first fertilization was given on the 7th day after transplanting, with 100 mL of diluted solution applied to each pot. Subsequent fertilizations were given every 7 days for a total of 4 applications (on days 7, 14, 21, and 28 after transplanting). The control (CK) treatment received the same amount of water. Except for the type of fertilizer, all treatments maintained the same water management (daily quantitative watering to maintain substrate moisture content at approximately 70% field capacity) and pest and disease control measures.

[0049] Seven days after the last fertilization (35 days after transplanting), plants with uniform growth were selected from each treatment for growth and physiological index measurements. Fruits from each treatment were harvested at the fruit ripening stage (red ripening stage) for yield and quality index measurements. The methods for measuring each index are as follows: (1) Plant height: The height from the substrate surface to the highest growth point of the plant is measured with a ruler, in cm.

[0050] (2) Stem diameter: The stem diameter at the second internode above the base of the plant is measured using an electronic vernier caliper, in mm.

[0051] (3) Relative chlorophyll content (SPAD value): The SPAD value of the third fully unfolded leaf from the top was measured using a SPAD-502 chlorophyll meter (Konica Minolta, Japan). The average value was taken from three different points on each leaf.

[0052] (4) Fresh weight of aboveground parts and fresh weight of underground parts: The plant was cut from the base of the stem, and the aboveground parts were weighed directly; the roots were rinsed with clean water and the surface moisture was absorbed before weighing. The unit is g. Root-to-shoot ratio = Fresh weight of underground parts / Fresh weight of aboveground parts.

[0053] (5) Root activity: Triphenyltetrazolium chloride (TTC) method was used. A cleaned root tip (approximately 0.5 g) was placed in a 10 mL test tube, and 5 mL each of 0.4% TTC solution and 0.1 mol / L phosphate buffer (pH 7.0) were added. The mixture was incubated at 37°C in the dark for 1 h. After removal, 2 mL of 1 mol / L sulfuric acid was added to terminate the reaction. The root segment was removed, blotted dry with filter paper, and extracted by grinding with ethyl acetate. The volume was adjusted to 10 mL, and the absorbance was measured at 485 nm. The amount of TTF generated was calculated based on the standard curve. Root activity is expressed in μgTTF·g. -1 Fresh weight·h -1 express.

[0054] (6) Number of fruits per plant: The total number of commercial fruits harvested from each plant during its entire growth period.

[0055] (7) Average weight of a single fruit: 10 commercial fruits were randomly selected from each treatment, weighed using an electronic balance, and the average weight was calculated in g.

[0056] (8) Yield per plant: Yield per plant (g) = number of fruits per plant × average weight of a single fruit.

[0057] (9) Vitamin C content: determined by 2,6-dichlorophenol titration method, referring to GB 5009.86-2016, unit mg / 100g fresh weight.

[0058] (10) Soluble sugar content: determined by anthrone-sulfuric acid colorimetric method, with glucose as standard, unit:

[0059] (11) Soluble protein content: determined by Coomassie Brilliant Blue G-250 staining method, with bovine serum albumin as standard, unit mg / g fresh weight.

[0060] All indicators were measured in triplicate. Data are expressed as mean ± standard deviation. One-way ANOVA was performed using SPSS 27.0 software, and multiple comparisons were performed using Duncan's method. The significance level was set at p < 0.05. The results are shown in Table 1.

[0061] Table 1. Effects of different liquid fertilizer treatments on tomato growth, yield, and quality.

[0062] Note: Data in the table are mean ± standard deviation (n=3); different lowercase letters in the same row indicate significant differences between treatments (p<0.05).

[0063] As shown in Table 1, the compound microbial seaweed fertilizer prepared in Example 3 of this invention has a significant promoting effect on the vegetative growth of tomato plants. Compared with the blank control (CK), the tomato plant height, stem diameter, SPAD value, aboveground fresh weight, and underground fresh weight of the treatment in Example 3 increased by 46.8%, 39.7%, 30.4%, 69.2%, and 77.8%, respectively, with all differences reaching a significant level (p<0.05). Compared with the three comparative treatments, the growth indicators of Example 3 were also significantly better than those of the comparative treatments, indicating that the synergistic system formed by the specific strain combination of the present invention for degrading seaweed and combining it with amino acid powder and humic acid has a significantly better promoting effect on crop growth than the default amino acid powder / humic acid component or the alternative strains.

[0064] The root activity of the treatment in Example 3 was 162.4 μg TTF·g -1 ·h -1 Compared to the control (CK), the root vigor was increased by 89.7%, and compared to comparative examples 1, 2, and 3, it was increased by 37.3%, 19.6%, and 25.3%, respectively. Regarding the root-to-shoot ratio, the treatment in Example 3 had a ratio of 0.194, slightly higher than the control treatments, indicating that the seaweed fertilizer of this invention not only promotes aboveground growth but also has a positive effect on root development, which is beneficial for establishing a good root-to-shoot coordinated growth relationship in crops. It is worth noting that although comparative examples 2 and 3 used different commercially available strains of the same species, their root vigor and root-to-shoot ratio were significantly lower than those in Example 3, indicating that the specific strains screened in this invention (such as BNCC103925 and BNCC381281) have irreplaceable unique advantages, and not every strain of the same species can achieve the same effect.

[0065] In terms of yield, Example 3 showed 13.2 fruits per plant, an average single fruit weight of 158.7 g, and a yield per plant of 2094.8 g, representing increases of 59.0%, 33.8%, and 112.8% compared to the control (CK); 23.4%, 19.1%, and 47.0% compared to Comparative Example 1; 16.8%, 11.4%, and 30.1% compared to Comparative Example 2; and 20.0%, 13.5%, and 36.2% compared to Comparative Example 3. The significant yield increase indicates that the microbial hydrolyzed seaweed fertilizer of this invention effectively improves tomato yield by promoting nutrient absorption and assimilate distribution.

[0066] The yield per plant in Comparative Example 1 was 1425.2 g, which was 44.8% higher than that of the control (CK), indicating that the seaweed fermentation degradation product alone had a certain yield-increasing effect on tomatoes. However, there was still a 47.0% yield difference compared to Example 3. This difference is precisely due to the synergistic effect contributed by the ternary synergistic system of seaweed fermentation degradation product + amino acid powder + humic acid. The same effect could not be achieved without any of the key components, which fully demonstrates the synergistic effect of "1+1+1>3" among the components of the formulation of this invention.

[0067] The yield per plant in Comparative Example 2 was 1610.3 g, significantly lower than that in Example 3. This result indicates that not all Bacillus strains with seaweed degradation capabilities can achieve a synergistic effect with other strains of this invention. Although Bacillus subtilis is a commonly used strain in the fertilizer field, its metabolic enzyme profile and fermentation metabolites are fundamentally different from those of Bacillus pumilus BNCC103925. Therefore, it cannot produce an effective synergistic degradation effect with Vibrio alginolyticus BNCC381281 and Pseudomonas schlegelii BNCC136904, resulting in insufficient release of seaweed active ingredients and ultimately affecting fertilizer efficiency.

[0068] The yield of a single plant in Comparative Example 3 was 1537.8 g, which was also significantly lower than that in Example 3. Although BNCC337013 and BNCC381281 are different strains of the same species, their ability to produce alginate lyase and their compatibility with other strains differ. This result further illustrates that the specific strains screened in this invention have been verified through systematic experiments, and their combined synergistic effect is not obvious; the same effect cannot be achieved simply by replacing similar strains.

[0069] Regarding fruit quality, the tomatoes treated in Example 3 had a vitamin C content of 23.6 mg / 100g, a soluble sugar content of 4.85%, and a soluble protein content of 7.03 mg / g, representing increases of 40.5%, 41.8%, and 44.7% respectively compared to the control (CK); 21.0%, 19.8%, and 22.9% respectively compared to Comparative Example 1; 13.5%, 13.3%, and 14.3% respectively compared to Comparative Example 2; and 16.3%, 16.0%, and 17.6% respectively compared to Comparative Example 3. These results indicate that the microbial hydrolyzed seaweed fertilizer of this invention significantly improves the nutritional quality of the fruit while increasing tomato yield, achieving a synergistic improvement in both yield and quality. This is mainly attributed to the combined effect of natural active substances, amino acid powder, humic acid, and trace elements in the seaweed fermentation degradation products, which promote the synthesis and accumulation of plant secondary metabolites.

[0070] Based on the data and analysis in Table 1, the following conclusions can be drawn: ① The compound microbial hydrolyzed seaweed fertilizer of this invention has a significantly better overall effect on promoting tomato growth, increasing yield, and improving quality than the three comparative examples and the blank control. ② Amino acid powder and humic acid are the key synergistic components in the formula of this invention. Together with seaweed fermentation degradation products, they form a ternary synergistic system of "degradation products-amino acids-humic acid". The absence of any one of these components will lead to a significant decrease in fertilizer efficiency. ③ The specific strain combination screened in this invention (Bacillus pumilus BNCC103925, Vibrio alginolyticus BNCC381281 and Pseudomonas schrenckii BNCC136904, etc.) has a unique synergistic degradation function that cannot be replaced by commercially available strains of the same species but with different numbers. ④ This invention realizes a complete technical chain of specific strains degrading seaweed, synergistic effect of amino acid powder and humic acid, and precise supplementation of trace elements. Each link is indispensable and together constitutes a complete technical solution that is not obvious.

[0071] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0072] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0073] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A compound microbial biodegradable seaweed fertilizer, characterized in that, It consists of the following components in parts by weight: 40-70 parts seaweed fermentation degradation product, 5-20 parts humic acid, 3-15 parts amino acid powder, 1-8 parts trace element additives, and 2-10 parts molasses; The seaweed fermentation degradation product is a degradation liquid obtained by fermenting and degrading seaweed raw materials with at least two of the following compound microbial agents: Bacillus pumilus BNCC103925, Bacillus tequilensis BNCC357969, Vibrio alginolyticus BNCC381281, and Pseudomonas stutzeri BNCC136904, and then filtering the product.

2. The compound microbial biodegradable seaweed fertilizer according to claim 1, characterized in that, The compound microbial agent contains two strains: Bacillus pumilus BNCC103925 and Pseudomonas schrenckii BNCC136904.

3. The compound microbial biodegradable seaweed fertilizer according to claim 1, characterized in that, The compound microbial agent contains three strains: Vibrio alginolyticus BNCC381281, Bacillus pumilus BNCC103925, and Bacillus tekirae BNCC357969.

4. The compound microbial biodegradable seaweed fertilizer according to claim 1, characterized in that, The trace element additive comprises the following components in parts by weight: 0.5-2 parts zinc sulfate, 0.5-2 parts boric acid, 0.5-1.5 parts manganese sulfate, and 0.1-0.5 parts ammonium molybdate.

5. The compound microbial biodegradable seaweed fertilizer according to claim 1, characterized in that, The seaweed raw material is selected from one or more of the following: giant kelp, kelp, Sargassum, bubbly seaweed, sea lettuce, bristle algae, and filamentous algae.

6. The compound microbial biodegradable seaweed fertilizer according to claim 1, characterized in that, The seaweed fertilizer is either liquid or solid.

7. A method for preparing the compound microbial biodegradable seaweed fertilizer as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Dry and pulverize the seaweed raw material to obtain seaweed powder; (2) Bacillus pumilus BNCC103925, Bacillus tekira BNCC357969, Vibrio alginolyticus BNCC381281 and Pseudomonas schrenckii BNCC136904 were respectively inoculated into LB liquid medium for activation and expansion. (3) Mix the various strains after expansion culture in proportion and inoculate them into seaweed fermentation culture medium for fermentation and degradation. Collect the fermentation broth, filter it, and obtain seaweed fermentation degradation product. (4) Mix the seaweed fermentation degradation product obtained in step (3) with humic acid, amino acid powder, trace element additives and molasses in the specified weight proportions to obtain liquid bacterial hydrolyzed seaweed fertilizer; or dry the mixture to obtain solid bacterial hydrolyzed seaweed fertilizer.

8. The application of the compound microbial biodegradable seaweed fertilizer as described in any one of claims 1 to 6 in promoting plant growth, increasing crop yield and quality, and improving soil.

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