Suaeda glauca rhizosphere growth-promoting bacterium preparation for targeted degradation of beach weeds and preparation method thereof

Abstract

The invention discloses a suaeda glauca rhizosphere growth-promoting bacterium preparation for targeted degradation of beach weeds and a preparation method of the suaeda glauca rhizosphere growth-promoting bacterium preparation. The preparation is prepared by compounding three specific functional strains, namely lactobacillus plantarum, bacillus atrophaeus and bacillus amyloliquefaciens, and supplementing with a composite carrier consisting of sodium alginate, humic acid and diatomite. The preparation method comprises the steps of strain activation, high-density fermentation, carrier pretreatment and spray adsorption forming. According to the invention, through the synergistic effect of multiple strains, on one hand, root exudates of an invasive plant Spartina alterniflora are degraded in a targeted manner, and weed suppression substances are secreted, so that the growth of the plant Spartina alterniflora is effectively inhibited; on the other hand, the strain is efficiently colonized at the rhizosphere of suaeda salsa to secrete growth-promoting substances and promote planting of suaeda salsa. The preparation is specially designed for a high-salt and high-humidity mudflat environment, the adversity survival and rhizosphere colonization capability of the strain is remarkably improved by the composite carrier, efficient coupling of biological control of mudflat invasive weeds and local vegetation ecological restoration is realized, and the preparation has the advantages of environmental friendliness, long lasting period and simplicity and convenience in application.

Description

Technical Field

[0001] This invention belongs to the field of environmental microbiology and ecological restoration technology, and specifically relates to a microbial preparation for tidal flat ecological restoration, its preparation method, and its application. Background Technology

[0002] Coastal tidal flat wetlands are invaluable resources with significant ecological and economic value, playing a crucial role in maintaining biodiversity, carbon sequestration, and resisting coastal erosion. Suaeda salsa, a typical pioneer plant and native species of tidal flats, not only improves saline-alkali soils and maintains wetland ecological balance but also possesses high economic and ornamental value. However, in recent years, the rampant spread of invasive species such as Spartina alterniflora and other tidal flat weeds has severely encroached on the living space of native vegetation like Suaeda salsa, leading to the degradation of tidal flat ecosystems and the loss of habitats, posing a serious challenge to coastal ecological restoration.

[0003] Currently, the mainstream technologies for controlling Spartina alterniflora and other tidal flat weeds include physical mowing, chemical weeding, and biological alternatives. While physical mowing is simple and direct, it is costly in terms of manpower and resources, and it is difficult to completely eliminate deep-rooted weeds, resulting in a high recurrence rate. Although chemical weeding is fast-acting, broad-spectrum herbicides can easily cause secondary pollution in the special environment of high salinity and high humidity in tidal flats, threatening the safety of benthic organisms and potentially spreading through water bodies, damaging the nearshore marine environment. Its use is being increasingly restricted. Biological alternatives (such as planting Suaeda salsa) are environmentally friendly, but the competitive advantage of weeds in the early stages of germination and growth often inhibits the establishment and growth of alternative plants, resulting in slow and unstable effectiveness.

[0004] There are obvious technical bottlenecks in the existing technology: First, there is a lack of effective control methods that are targeted and environmentally friendly for invasive weeds. Existing methods often "kill a thousand enemies but lose eight hundred of your own," damaging the fragile tidal flat microbial community and soil structure while clearing weeds. Second, there is an emphasis on "clearing but neglect of restoration," failing to effectively couple weed control with the rapid recovery of native vegetation, leading to the risk of re-invasion or ecological degradation of the treated tidal flats. Third, conventional microbial agents have single functions, focusing only on promoting growth or suppressing weeds, making it difficult to form a synergistic effect in the complex tidal flat environment, resulting in limited and unstable effects.

[0005] Furthermore, the high salinity and flooding conditions of tidal flats pose significant challenges to the survival and colonization of microbial agents. The number of viable bacteria drops sharply after application of ordinary microbial agents, rendering them ineffective. Therefore, there is an urgent need in this field to develop a novel, green, and sustainable microbial management technology and product that can specifically target tidal flat weeds, efficiently promote the colonization and growth of *Suaeda salsa*, and adapt to the harsh environment of tidal flats. Summary of the Invention

[0006] To address the above-mentioned problems, this invention discloses a rhizosphere growth-promoting bacteria preparation for targeted degradation of tidal flat weeds and its preparation method.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] A rhizosphere-promoting bacterial preparation for targeted degradation of tidal flat weeds, comprising active ingredients and auxiliary ingredients, with the following composition based on the total number of live bacteria per gram of preparation:

[0009] Lactobacillus plantarum, which has the ability to degrade the root secretions of weeds on tidal flats

[0010] Lactiplantibacillusplantarum5.0×10 8 ~2.0×10 9 CFU / g;

[0011] Bacillus atrophaeus, a bacterium capable of producing herbicides

[0012] 3.0×10 8 ~1.5×10 9 CFU / g;

[0013] Bacillus amyloliquefaciens, a bacterium capable of secreting plant growth-promoting substances, 2.0 × 10⁻⁶ 8 ~1.0×10 9 CFU / g;

[0014] Sodium alginate 1-3 wt%;

[0015] 2-5 wt% humic acid;

[0016] Diatomaceous earth balance.

[0017] Furthermore, in the aforementioned targeted degradation of tidal flat weeds by the rhizosphere-promoting bacteria preparation of *Suaeda salsa*, the *Lactobacillus plantarum* strain is a commercial strain *Lactiplantibacillus plantarum* ATCC 8014 or a strain with equivalent function; the *Bacillus atrophaeus* strain is a commercial strain *Bacillus atrophaeus* ATCC 51189 or a strain with equivalent function; and the *Bacillus amyloliquefaciens* strain is a commercial strain *Bacillus amyloliquefaciens* FZB42 or a strain with equivalent function.

[0018] Furthermore, the aforementioned Suaeda salsa rhizosphere growth-promoting bacterial preparation for targeted degradation of tidal flat weeds has a pH value of 6.5-7.5 and a water content of ≤8%.

[0019] This invention also discloses a method for preparing the above-mentioned Suaeda salsa rhizosphere growth-promoting bacteria preparation that targets and degrades tidal flat weeds, comprising the following steps:

[0020] (1) Activation and propagation of strains: Lactobacillus plantarum, Bacillus atrophus and Bacillus amyloliquefaciens were inoculated into the corresponding liquid culture medium and cultured at 30-37℃ and 150-220r / min for 18-24 hours to obtain primary seed liquid;

[0021] (2) High-density fermentation: Each primary seed culture is transferred to a fermenter at an inoculation rate of 5-10% for high-density fermentation. The fermentation temperature, pH, and dissolved oxygen are controlled until the cell concentration reaches 10. 9 ~10 10 CFU / mL was used to obtain the fermentation broth;

[0022] (3) Pretreatment of adsorption carrier: Dry and sterilize diatomaceous earth at 120-140℃ for 2-3 hours, cool it and mix it evenly with humic acid and sodium alginate powder to obtain mixed carrier;

[0023] (4) Formulation: The three fermentation liquids obtained in step (2) are mixed in the proportions described in claim 1, and sprayed evenly onto the mixed carrier obtained in step (3). While spraying, the mixture is stirred and dried at low temperature until the water content is ≤8%. The mixture is then crushed and sieved to obtain the bacterial preparation.

[0024] Furthermore, in the above preparation method, the fermentation culture medium of *Lactobacillus plantarum* in step (2) contains 10-15 g / L tryptone, 5-10 g / L yeast extract, 20-30 g / L glucose, 2 g / L diammonium hydrogen citrate, 5 g / L sodium acetate, 0.2 g / L magnesium sulfate, 0.05 g / L manganese sulfate, and natural pH.

[0025] Furthermore, in the above preparation method, the low-temperature drying in step (4) is carried out by fluidized bed drying or vacuum freeze drying, and the drying temperature is controlled at 30-40℃.

[0026] This invention also discloses the application of the above-mentioned Suaeda salsa rhizosphere growth-promoting bacteria preparation in coastal mudflat ecological restoration, which inhibits the growth of Spartina alterniflora and promotes the growth of Suaeda salsa, thereby restoring the mudflat vegetation community.

[0027] Furthermore, in the above application, the method of application is to mix the bacterial preparation with an appropriate amount of fine sand and then apply it around the root zone when planting Suaeda salsa, or to prepare a bacterial suspension for root irrigation; the application rate of the bacterial preparation is no less than 5.0 × 10⁻⁶ effective live bacteria per hectare of tidal flat. 13 CFU.

[0028] Furthermore, in pot experiments simulating tidal flat environments, after 60 days of application, the above-mentioned application of this preparation resulted in a plant height inhibition rate of ≥40% and a fresh weight inhibition rate of ≥50% for Spartina alterniflora; at the same time, it promoted plant height of Suaeda salsa by ≥25% and biomass by ≥30%.

[0029] Compared with existing technologies, the present invention has the following advantages and beneficial effects:

[0030] 1. Highly targeted and environmentally friendly: By utilizing the specific action mechanism of functional strains on the rhizosphere environment of Spartina alterniflora, precise weed control can be achieved, avoiding secondary pollution and damage to the tidal flat ecological environment caused by chemical herbicides. It is a green and sustainable biological governance technology.

[0031] 2. Synergistic and efficient "weed suppression-growth promotion": Through the scientific combination of three strains, the two processes of suppressing invasive weeds and promoting the growth of native plants are combined into one, forming an efficient ecological restoration closed loop. This solves the problem of "only destroying without building" in traditional governance and significantly improves the efficiency and stability of tidal flat ecological restoration.

[0032] 3. Strong adaptability to adversity and colonization ability: The unique sodium alginate-humic acid-diatomite composite carrier system not only provides physical protection for the bacterial agent, but its water retention, nutrition and adhesion properties also greatly enhance the survival rate of functional strains under adverse conditions such as high salinity and flooding in tidal flats and their colonization ability in the rhizosphere of Suaeda salsa, ensuring the long-lasting and stable effect of the preparation.

[0033] 4. Low application cost and simple operation: The formulation is in solid powder form, which is easy to store, transport and apply. It can be directly applied or prepared into a bacterial suspension for root irrigation. No complicated equipment is required, making it very suitable for large-scale promotion and application in the vast tidal flat environment. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. All raw materials used in the embodiments of this invention are commercially available.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0036] Example 1

[0037] A rhizosphere-promoting bacterial preparation for targeted degradation of tidal flat weeds, comprising active ingredients and auxiliary ingredients, with the following composition based on the total number of live bacteria per gram of preparation:

[0038] Lactobacillus plantarum ATCC 80145.0×10 8 CFU / g;

[0039] Bacillus atrophaeus ATCC 511893.0×10 8 CFU / g;

[0040] Bacillus amyloliquefaciens FZB42 2.0×10 8 CFU / g;

[0041] 1 wt% sodium alginate;

[0042] 2 wt% humic acid;

[0043] Diatomaceous earth balance.

[0044] Its preparation method includes the following steps:

[0045] (1) Activation and propagation of strains: Glycerol tubes of Lactobacillus plantarum ATCC 8014, Bacillus atrophus ATCC 51189 and Bacillus amyloliquefaciens FZB42 were inoculated into MRS medium, LB medium and NA medium respectively, and cultured at 37℃ and 180r / min for 20 hours to obtain primary seed culture;

[0046] (2) High-density fermentation: Each primary seed culture was transferred to a 50L fermenter at an inoculation rate of 8% for scale-up culture. *Lactobacillus plantarum* was fermented on MRS medium at 30℃ for 24 hours; *Bacillus* was fermented on LB medium at 37℃ for 36 hours. After fermentation, the cells were collected by centrifugation, resuspended in physiological saline, and the concentration of each bacterial suspension was adjusted to 1.0 × 10⁻⁶. 10 CFU / mL, to obtain a high concentration bacterial suspension;

[0047] (3) Pretreatment of adsorption carrier: The diatomaceous earth was dried and sterilized at 130℃ for 2.5 hours. After cooling, it was mixed evenly with humic acid powder and sodium alginate powder in proportion to obtain a mixed carrier.

[0048] (4) Formulation: The three high-concentration bacterial suspensions obtained in step (2) are mixed in the above proportions and sprayed evenly onto the constantly turning mixing carrier using a small spraying device to ensure uniform spraying. Then, the mixture is dried in a fluidized bed at 35°C until the moisture content is 7.5%, pulverized and passed through an 80-mesh sieve, and packaged to obtain the powdered bacterial preparation.

[0049] Example 2

[0050] A rhizosphere-promoting bacterial preparation for targeted degradation of tidal flat weeds, comprising active ingredients and auxiliary ingredients, with the following composition based on the total number of live bacteria per gram of preparation:

[0051] Lactobacillus plantarum ATCC 8014 1.2×10 9 CFU / g;

[0052] Bacillus atrophaeus ATCC 511899.0×10 8 CFU / g;

[0053] Bacillus amyloliquefaciens FZB4 26.0 × 10 8 CFU / g;

[0054] Sodium alginate 2wt%;

[0055] Humic acid 3.5 wt%;

[0056] Diatomaceous earth balance.

[0057] The preparation method is the same as in Example 1, but the final bacterial count is controlled within the target range by adjusting the mixing ratio of the bacterial suspension and the spraying amount.

[0058] Example 3

[0059] A rhizosphere-promoting bacterial preparation for targeted degradation of tidal flat weeds, comprising active ingredients and auxiliary ingredients, with the following composition based on the total number of live bacteria per gram of preparation:

[0060] Lactobacillus plantarum ATCC 80142.0×10 9 CFU / g;

[0061] Bacillus atrophaeus ATCC 511891.5×10 9 CFU / g;

[0062] Bacillus amyloliquefaciens FZB42 1.0 × 10 9 CFU / g;

[0063] 3 wt% sodium alginate;

[0064] 5 wt% humic acid;

[0065] Diatomaceous earth balance.

[0066] The preparation method is the same as in Example 1, but the final bacterial count is controlled within the target range by adjusting the mixing ratio of the bacterial suspension and the spraying amount.

[0067] Comparative Example 1

[0068] A microbial preparation, whose composition and preparation method are basically the same as those in Example 2, except that it does not contain *Lactobacillus plantarum* ATCC 8014. The amount of diatomaceous earth in the preparation is increased accordingly to make up the weight difference.

[0069] Comparative Example 2

[0070] A microbial preparation, whose composition and preparation method are basically the same as those in Example 2, except that it does not contain Bacillus atrophaeus ATCC 51189. The amount of diatomaceous earth in the preparation is increased accordingly to make up the weight difference.

[0071] Comparative Example 3

[0072] A microbial preparation, whose composition and preparation method are basically the same as those in Example 2, except that it does not contain Bacillus amyloliquefaciens FZB42. The amount of diatomaceous earth in the preparation is increased accordingly to make up the weight difference.

[0073] Comparative Example 4

[0074] A microbial preparation, whose composition and preparation method are basically the same as those in Example 2, except that it does not contain sodium alginate and humic acid. The auxiliary components consist only of diatomaceous earth.

[0075] Comparative Example 5

[0076] A conventional single-strain growth promoter, the active ingredient of which is Bacillus amyloliquefaciens FZB42, with a viable count of 1.5 × 10⁻⁶. 9 The concentration is CFU / g, and the carrier is peat moss. The preparation method involves simply adsorbing the bacterial solution onto the carrier and then drying it.

[0077] Test Example 1

[0078] Pot experiment on targeted weed suppression and growth promotion effects

[0079] Objective: To verify the inhibitory effect of the bacterial preparation of the present invention on Spartina alterniflora and its growth-promoting effect on Suaeda salsa in a simulated tidal flat environment.

[0080] method:

[0081] Experimental setup: Pot experiments were conducted in a greenhouse. Plastic pots (30cm in diameter, 25cm in height) were filled with intertidal mud (salinity ~15‰), and each pot contained 5 uniformly growing *Spartina alterniflora* seedlings and 5 *Suaeda salsa* seedlings. The following treatment groups were set up: the preparation group from Example 2, Comparative Example 1 (lacking *Lactobacillus plantarum*), Comparative Example 2 (lacking *Bacillus atrophus*), Comparative Example 3 (lacking *Bacillus amyloliquefaciens*), Comparative Example 4 (lacking the composite carrier), Comparative Example 5 (single growth-promoting bacterial agent), and a blank control group (treated with an equal amount of sterilized diatomaceous earth). Each group had 5 replicates.

[0082] Application method: After the plants have recovered and established themselves, mix each bacterial preparation with a small amount of fine sand and evenly sprinkle it around the roots of the plants. The application amount is 2 grams of preparation per pot (containing approximately 2 × 10^9 CFU of total live bacteria).

[0083] Management and Measurement: Periodically irrigate with brackish water (salinity 10‰) to simulate a tidal environment. Destructive sampling is performed 60 days after treatment.

[0084] Herbicide suppression effect determination: The plant height and above-ground fresh weight of all Spartina alterniflora plants in each pot were measured, and the inhibition rate (%) relative to the blank control group was calculated.

[0085] Growth-promoting effect determination: The plant height and above-ground fresh weight of all Suaeda salsa plants in each pot were measured, and the growth promotion rate (%) relative to the blank control group was calculated.

[0086] Results: See Table 1.

[0087] Table 1: Effects of weed suppression and growth promotion in potted plants (60 days).

[0088]

[0089] Note: Different letters after the data in the same column indicate that the difference is significant at the P<0.05 level (Duncan's new multiple range method).

[0090] Conclusion: The formulation of Example 2 of this invention exhibited the strongest overall effect, with both herbicide inhibition and growth promotion effects significantly superior to those of the comparative groups (P<0.05). Comparative Group 1 (lacking degrading bacteria) showed a significant decrease in herbicide inhibition, confirming the key role of *Lactobacillus plantarum* in the targeted degradation of weed root exudates; Comparative Group 2 (lacking herbicide-inhibiting bacteria) showed the weakest herbicide inhibition, confirming that *Bacillus atrophus* is the main producer of herbicide-inhibiting substances; Comparative Group 3 (lacking growth-promoting bacteria) lost its growth-promoting effect, confirming that *Bacillus amyloliquefaciens* is mainly responsible for promoting the growth of *Suaeda salsa*; Comparative Group 4 (lacking a composite carrier) showed a comprehensive decrease in effect, confirming that the carrier composed of sodium alginate and humic acid is crucial for bacterial colonization; Comparative Group 5 (single bacteria) showed the worst effect, demonstrating that the synergistic effect of the three bacteria combination is the core of the formulation's high efficiency.

[0091] Test Example 2

[0092] Survival and colonization tests of the formulation in tidal flat environments

[0093] Objective: To verify the effect of the composite vector on protecting functional strains against high salinity stress in tidal flats and enhancing their colonization ability in the rhizosphere of Suaeda salsa.

[0094] method:

[0095] Sample preparation: The formulations of Example 2 and Comparative Example 4 (lacking a composite carrier, the bacterial solution was directly adsorbed onto sterile diatomaceous earth) were used as test objects.

[0096] High-salt stress survival experiment: The two preparations were inoculated into liquid culture medium containing 15‰ NaCl and cultured at 30℃ with shaking at 150 r / min. Samples were taken at 0 h, 24 h, 48 h, and 72 h, and the total number of viable bacteria was counted using the dilution plating method.

[0097] Rhizosphere colonization experiment: At the end of the pot experiment in Test Example 1, rhizosphere soil samples (soil tightly attached to the root surface) of Suaeda salsa from Example 2 group and Comparative Example 4 group were taken. 1g of soil sample was weighed, serially diluted with sterile physiological saline, spread on the corresponding selective medium, and the number of functional colonies (CFU / g) in each gram of rhizosphere soil was counted.

[0098] Results: See Tables 2 and 3.

[0099] Table 2: Changes in viable bacterial count under high-salt stress (15‰ NaCl) (×10^8 CFU / mL, n=3)

[0100] Table 3: Number of functional bacteria in the rhizosphere soil of Suaeda salsa (log10 CFU / g soil, n=5)

[0101]

[0102] Note: Different letters after the data in the same row indicate that the difference is significant at the P<0.05 level.

[0103] Conclusion: The composite carrier (sodium alginate + humic acid) significantly enhanced the survival ability of functional strains under high-salt stress (Table 2). The number of strains in the formulation of Example 2 colonizing the rhizosphere of Suaeda salsa was significantly higher than that of Comparative Example 4 (Table 3), indicating that the carrier system can effectively protect the strains through the rhizosphere microenvironment and promote their adsorption and reproduction, which is the basis for its long-lasting efficacy.

[0104] Test Example 3

[0105] Evaluation of the effect of the on-site demonstration area of ​​tidal flats

[0106] Objective: To evaluate the effect of the bacterial preparation of the present invention on the restoration of vegetation communities in actual tidal flat environments.

[0107] method:

[0108] Demonstration area establishment: 10m×10m quadrats were set up in tidal flats (salinity 12-18‰) invaded by Spartina alterniflora. Treatment areas (applied with the formulation of Example 2, 50kg / hectare) and control areas (no formulation applied) were set up, with 3 replicates for each treatment.

[0109] Application of fungicide and planting: In spring, after manually removing most of the above-ground parts of Spartina alterniflora, mix the fungicide preparation with fine sand and spread it evenly. At the same time, manually and evenly sow Suaeda salsa seeds (5g / m²). 2 ).

[0110] Monitoring and survey: Vegetation was surveyed using the quadrat method at 3 and 6 months after treatment.

[0111] Record the density (plants / m2) of Spartina alterniflora and Suaeda salsa within the quadrat.

[0112] The aboveground parts of all plants within the quadrat were harvested, and their biomass (fresh weight, g / m²) was measured. 2 ).

[0113] The inhibitory effect of Spartina alterniflora and the establishment effect of Suaeda salsa were calculated.

[0114] Results: See Table 4.

[0115] Table 4: Changes in vegetation communities in the tidal flat demonstration area (6 months later).

[0116]

[0117] Conclusion: In actual tidal flat environments, after 6 months of application of the formulation of this invention, the population of Spartina alterniflora in the treated area was effectively suppressed, with its density and biomass significantly lower than that in the control area. Simultaneously, the settlement and growth of Suaeda salsa were significantly promoted, with its biomass more than four times that of the control area. This indicates that the formulation of this invention can effectively regulate the structure of tidal flat vegetation communities, suppress invasive weeds, and promote the recovery of native pioneer plants, demonstrating good potential for practical application.

[0118] Test Case Summary: Through pot experiments, stress survival tests, and field demonstration area evaluation, the efficacy of the formulation of this invention was quantitatively verified. The pot experiment (n=5) showed that after 60 days of application, the formulation of Example 2 inhibited the plant height and fresh weight of *Spartina alterniflora* by 48.5% and 59.2%, respectively, and promoted the plant height and fresh weight of *Suaeda salsa* by 32.6% and 39.5%, respectively, significantly outperforming the comparative examples with all missing components (P<0.05). Under high salinity (15‰) stress, the viable bacterial count of the formulation of Example 2 remained at 7.5 × 10⁻⁶ after 72 hours. 8 The CFU / mL count was significantly reduced in Comparative Example 4 (lacking the composite carrier), while the viable count decreased to 0.9 × 10⁻⁶.8 The concentration of CFU / mL confirmed that the vector had a strong protective effect on the strain. After 6 months of field application, the biomass inhibition rate of Spartina alterniflora in the treatment area reached 79.2%, and the biomass of Suaeda salsa increased by 321.6% compared with the control area, showing a significant improvement in vegetation community structure.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention specification, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of protection of the present invention patent.

Claims

1. A rhizosphere growth-promoting bacterial preparation for targeted degradation of tidal flat weeds, characterized in that, Composed of active ingredients and auxiliary ingredients, its composition, based on the total number of live bacteria per gram of preparation, is as follows: Lactobacillus plantarum 5.0 × 10⁻⁶ has the ability to degrade the root exudates of weeds on tidal flats. 8 ~2.0×10 9 CFU / g; Bacillus atrophaeus, a bacterium capable of producing herbicides 3.0×10 8 ~1.5×10 9 CFU / g; Bacillus amyloliquefaciens, which has the ability to secrete plant growth-promoting substances amyloliquefaciens 2.0×10 8 ~1.0×10 9 CFU / g; Sodium alginate 1-3 wt%; 2-5 wt% humic acid; Diatomaceous earth balance.

2. The rhizosphere growth-promoting bacteria preparation of *Suaeda salsa* according to claim 1, characterized in that: The *Lactobacillus plantarum* strain is the commercial strain *Lactiplantibacillus plantarum* ATCC 8014 or a strain with equivalent function; the *Bacillus atrophaeus* strain is the commercial strain *Bacillus atrophaeus* ATCC 51189 or a strain with equivalent function; and the *Bacillus amyloliquefaciens* strain is the commercial strain *Bacillus amyloliquefaciens* FZB42 or a strain with equivalent function.

3. The rhizosphere growth-promoting bacteria preparation of *Suaeda salsa* according to claim 1, characterized in that: The bacterial preparation has a pH value of 6.5-7.5 and a water content of ≤8%.

4. A method for preparing a Suaeda salsa rhizosphere growth-promoting bacterial preparation for targeted degradation of tidal flat weeds as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Activation and propagation of strains: Lactobacillus plantarum, Bacillus atrophus and Bacillus amyloliquefaciens were inoculated into the corresponding liquid culture medium and cultured at 30-37℃ and 150-220r / min for 18-24 hours to obtain primary seed liquid; (2) High-density fermentation: Each primary seed culture is transferred to a fermenter at an inoculation rate of 5-10% for high-density fermentation. The fermentation temperature, pH, and dissolved oxygen are controlled until the cell concentration reaches 10. 9 ~10 10 CFU / mL was used to obtain the fermentation broth; (3) Pretreatment of adsorption carrier: Dry and sterilize diatomaceous earth at 120-140℃ for 2-3 hours, cool it and mix it evenly with humic acid and sodium alginate powder to obtain mixed carrier; (4) Formulation: The three fermentation liquids obtained in step (2) are mixed in the proportions described in claim 1, and sprayed evenly onto the mixed carrier obtained in step (3). While spraying, the mixture is stirred and dried at low temperature until the water content is ≤8%. The mixture is then crushed and sieved to obtain the bacterial preparation.

5. The preparation method according to claim 4, characterized in that: The fermentation medium for Lactobacillus plantarum described in step (2) contains 10-15 g / L tryptone, 5-10 g / L yeast extract, 20-30 g / L glucose, 2 g / L diammonium hydrogen citrate, 5 g / L sodium acetate, 0.2 g / L magnesium sulfate, and 0.05 g / L manganese sulfate, with a natural pH.

6. The preparation method according to claim 4, characterized in that: The low-temperature drying in step (4) is carried out by fluidized bed drying or vacuum freeze drying, and the drying temperature is controlled at 30-40℃.

7. The application of the *Suaeda salsa* rhizosphere growth-promoting bacteria preparation according to any one of claims 1-3, characterized in that: It is used in the ecological restoration of coastal mudflats to restore the mudflat vegetation community by inhibiting the growth of Spartina alterniflora and promoting the growth of Suaeda salsa.

8. The application according to claim 7, characterized in that: The application method involves mixing the aforementioned microbial preparation with an appropriate amount of fine sand and then applying it around the root zone during the planting of Suaeda salsa, or preparing a microbial suspension for root irrigation; the application rate of the microbial preparation is no less than 5.0 × 10⁻⁶ effective live bacteria per hectare of tidal flat. 13 CFU.

9. The application according to claim 7, characterized in that: In a pot experiment simulating a tidal flat environment, after 60 days of application of this preparation, the plant height inhibition rate of Spartina alterniflora was ≥40%, and the fresh weight inhibition rate was ≥50%; at the same time, the plant height promotion rate of Suaeda salsa was ≥25%, and the biomass promotion rate was ≥30%.

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