A method for promoting the growth of dog tooth grass on a steel slag flat bed based on microbial organic matrix

Abstract

The application discloses a method for promoting growth of cymbidium on a steel slag flat bed based on microbial organic matrix, and belongs to the technical field of steel slag resource utilization. The application inoculates eight kinds of bacillus agents with different concentrations on the bacterial residue to prepare the organic matrix, and then covers the matrix on the converter slag to promote the growth of cymbidium on the converter slag, and selects the bacillus strain with the best growth promotion effect and the most suitable inoculation concentration. The results show that after being inoculated with bacillus megaterium, bacillus polymyxa and bacillus mucilaginosus, the sucrose activity of the soil is enhanced; the hydrogen peroxide activity of the soil in the four groups of treatments inoculated with the bacillus agent is stronger than that in the control group; the application of the bacillus megaterium, bacillus polymyxa and bacillus mucilaginosus enhances the urease activity in the soil; the inoculation of the bacillus megaterium promotes the release of Ca and P elements in the soil and the absorption of Ca, P, Mg, Mn and Si elements by the plant.

Description

Technical Field

[0001] This invention belongs to the technical field of steel slag resource utilization, specifically relating to a method for promoting the growth of bermudagrass on steel slag beds based on microbial organic matrix. Background Technology

[0002] Traditional soil-based turf production faces an urgent need for transformation. Utilizing abandoned or marginal land for soilless turf production is an effective way to address this need, and selecting economical and efficient soilless turf substrates is the primary measure.

[0003] Currently, most soilless turf production uses river sand, vermiculite, or agricultural waste such as carbonized straw and mushroom residue. However, the overall cost of the turf substrate is relatively high. Therefore, there is an urgent need to screen for soilless turf substrate materials that can meet the growth needs of turfgrass while remaining inexpensive. Research has found that steel slag contains a large amount of elements beneficial to plant growth, such as silicon, iron, phosphorus, calcium, and magnesium, which have important application value in soil improvement and promoting plant growth. However, research on its application in turf production is still lacking.

[0004] Mushroom residue, also known as waste mushroom substrate or mushroom bran, refers to the waste left over after harvesting the finished mushrooms during the cultivation of edible fungi. It is a residue of the mushroom substrate. Although mushroom residue can be used as animal feed, field fertilizer, and recycled as raw material for edible fungi, most of it is currently discarded indiscriminately, leading to mold and rot. This not only wastes valuable resources but also pollutes the environment and affects the aesthetics.

[0005] From the perspective of utilizing bacterial residue and revegetating converter slag heaps, the preparation of organic substrates by inoculating different types and concentrations of Bacillus inoculants on bacterial residue to promote the growth of Bermuda grass on converter slag, with the aim of screening out the Bacillus strain with the best growth-promoting effect and the optimal inoculation concentration, has become a problem that needs to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for promoting the growth of bermudagrass on steel slag beds based on microbial organic matrix in order to solve the problems mentioned in the background art or achieve better technical effects.

[0007] To solve the above-mentioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention. This invention discloses a method for promoting the growth of bermudagrass on steel slag beds based on a microbial organic matrix, the steps of which are as follows:

[0008] S1: Inoculate Bacillus powder into an Erlenmeyer flask containing LB liquid medium, stir and incubate for 24 hours to obtain the initial culture solution;

[0009] S2: Spread the initial bacterial culture obtained in S1 evenly onto an LB solid culture dish, then incubate the culture dish in the dark to activate it. Based on the color and morphological characteristics of the colonies, pick a single colony of the activated bacteria and inoculate it into LB liquid culture medium. After shaking culture for 24 hours, use a UV spectrophotometer at λ=660nm to adjust the transmittance of the bacterial culture to 50% and use it as the stock solution for later use.

[0010] S3: Set a reasonable bacterial concentration gradient, calculate the amount of each bacterial stock solution required for a specific mass of composted bacterial residue, prepare it in centrifuge tubes, and dilute the bacterial stock solutions of different treatment concentrations to the standard mark with sterile water. Then add them to a specific mass of air-dried bacterial residue in portions and mix them evenly. Allow the bacterial strains to colonize on the organic substrate for 3 days to obtain the microbial organic substrate used in the experiment.

[0011] S4: Take naturally dried converter slag and fill it into a flowerpot. Cover the surface of the converter slag evenly with the microbial organic matrix prepared in S3. Bury the torn Bermuda grass stems into the microbial organic matrix. Then, water twice a day for the first 15 days and once a day for the next 14 days.

[0012] S5: Observe the growth and propagation of bermudagrass in the flower pots every week, and screen them based on the appearance of the lawn.

[0013] Furthermore, in S1, the viable count of Bacillus powder in the Erlenmeyer flask is 1 × 10⁻⁶. 11 The LB liquid culture medium is 100 mL.

[0014] Furthermore, in S1, the temperature for stirring and culturing is 37°C, and the stirring condition is 150 rpm.

[0015] Furthermore, in S1, the Bacillus is selected from one of Bacillus megaterium, Bacillus polymyxa, Bacillus laterosporus, Bacillus amyloliquefaciens, Bacillus mucilaginosus, Bacillus subtilis, and Bacillus licheniformis.

[0016] Furthermore, in S2, the method for picking the activated bacteria is as follows: after the colony grows, use a sterilized inoculation loop near the flame of an alcohol lamp to scrape off a single activated colony that is growing vigorously, has neat edges, and is free from contamination by other bacteria, and quickly inoculate the inoculation loop into LB liquid culture medium.

[0017] Furthermore, in S2, the conditions for oscillation culture are 28°C and 230 rpm.

[0018] Furthermore, in step S2, the concentration of viable bacteria in the stock solution is 1×10⁻⁶. 9 cfu / mL.

[0019] Furthermore, in S3, the bacterial concentration gradient is set to: 0.5x, recommended concentration, 2x, and 4x.

[0020] Furthermore, in S4, the particle size of the converter slag is 0.2~1.0mm, and the sum of the contents of CaO and P2O5 in the converter slag exceeds 47%.

[0021] Furthermore, in S4, the mass ratio of the microbial organic substrate to the shredded Bermuda grass stems is 10:1.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) From the perspective of utilizing bacterial residue and revegetating converter steel slag pile, this invention prepares an organic matrix by inoculating eight kinds of Bacillus agents of different concentrations onto bacterial residue, and then covers it onto converter slag to promote the growth of bermudagrass on converter slag, in order to screen out the Bacillus strain with the best growth-promoting effect and the most suitable inoculation concentration.

[0024] (2) The present invention measured the rhizosphere soil enzyme activity and the element content of soil and aboveground plants in the inoculated Bacillus inoculum and the control group. The results showed that: after inoculation with Bacillus megaterium, Bacillus polymyxa, and Bacillus mucilaginosus, the sucrase activity of the soil was enhanced; the catalase activity of the soil in the four treatments inoculated with Bacillus inoculum was stronger than that of the control group; the application of Bacillus megaterium, Bacillus polymyxa, and Bacillus mucilaginosus inoculum enhanced the urease activity in the soil; inoculation with Bacillus megaterium promoted the release of Ca and P elements in the soil and the absorption of Ca, P, Mg, Mn, and Si elements by plants; Bacillus polymyxa promoted the release of Ca in the soil and the absorption of P, K, Mg, and Mn elements by plants; Bacillus amyxa promoted the release of S elements in the soil and the absorption of P, K, and Mg elements by plants; and Bacillus mucilaginosus promoted the release of P in the soil and the absorption of P, K, S, and Mn elements by plants.

[0025] (3) This invention, by inoculating with four types of microbial agents—Bacillus polymyxa, Bacillus mucilaginosus, Bacillus megaterium, and Bacillus aspergillus—increased the rhizome density of Bermuda grass by 80%, 67%, 77%, and 80%, respectively, compared to the blank sample. The stolons treated with Bacillus mucilaginosus exhibited the fastest growth rate, showing a significant difference in growth rate compared to Bacillus aspergillus, Bacillus megaterium, and the control group. The stolons treated with Bacillus polymyxa showed a significantly higher growth rate than Bacillus megaterium and the control group, while the stolons treated with Bacillus aspergillus showed no significant difference in growth rate compared to Bacillus megaterium and the control group. Therefore, the stolon growth rate, from fastest to slowest, was: Mucilaginosus > Bacillus polymyxa > Bacillus aspergillus > Bacillus megaterium > Control.

[0026] (4) There are significant differences in root surface area and total root volume among the different treatments of the present invention. The root surface area of ​​the Bacillus polymyxa treatment group is the largest, reaching 20.78 cm². 2The root surface area of ​​the *Bacillus polymyxa* treatment was significantly larger than that of the other treatments, increasing by 86.87% compared to the control group. Compared to the control group, the total root volume of the *Bacillus polymyxa* and *Bacillus megaterium* treatments increased by 88.89% and 77.78%, respectively. However, there was no significant difference in the total root volume between the two treatments and the other treatments.

[0027] (5) The sucrase activity in the soil inoculated with Bacillus polymyxa was significantly higher than that in other treatments. The sucrase activity in the soil treated with Bacillus amyxa was significantly different from that in the control group, but the increase was small. The sucrase activity in the soil treated with Bacillus polymyxa, Bacillus colloidis, and Bacillus megaterium was significantly increased compared with the control group, by 111.9%, 86.75%, and 86.44%, respectively. Attached Figure Description

[0028] Figure 1 This is a diagram showing the effect of different treatment conditions on the density of turfgrass stems according to the present invention;

[0029] Figure 2 This diagram illustrates the effect of different treatment conditions on the growth rate of turfgrass runners under the present invention.

[0030] Figure 3 This is a graph showing the effect of different treatment conditions on the SPAD value of turfgrass according to the present invention;

[0031] Figure 4 This is a diagram showing the effect of different treatment conditions on the root morphology of turfgrass according to the present invention;

[0032] Figure 5 This is a graph showing the effect of different treatment conditions on the dry weight and root-to-shoot ratio of turfgrass according to the present invention;

[0033] Figure 6 This is a diagram showing the effect of different treatment conditions on the root vigor of turfgrass according to the present invention;

[0034] Figure 7 This is a graph showing the effect of different treatment conditions on soil sucrase activity according to the present invention;

[0035] Figure 8 This is a graph showing the effect of different treatment conditions on soil catalase activity according to the present invention;

[0036] Figure 9 This is a graph showing the effect of different treatments on soil urease activity under the present invention.

[0037] Figure 10 This is a phenotypic diagram comparing lawns treated with Bacillus argentis and the control group according to the present invention;

[0038] Figure 11 This is a phenotypic diagram comparing lawns treated with Bacillus laterosporus and the control group according to the present invention;

[0039] Figure 12 This is a phenotypic diagram comparing lawns treated with Bacillus licheniformis and the control group according to the present invention;

[0040] Figure 13 This is a phenotypic comparison of lawn treated with Bacillus polymyxa and the control group according to the present invention;

[0041] Figure 14 This is a phenotypic diagram comparing lawns treated with Bacillus mucilaginosus and the control group according to the present invention;

[0042] Figure 15 This is a phenotypic diagram comparing lawns treated with Bacillus amyloliquefaciens and the control group according to the present invention;

[0043] Figure 16 This is a phenotypic comparison of lawn treated with Bacillus megaterium and the control group according to the present invention;

[0044] Figure 17 This is a phenotypic comparison of lawns treated with Bacillus subtilis and the control group according to the present invention. Detailed Implementation

[0045] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0046] Unless otherwise specified, all raw materials or reagents used in the following examples are commercially available products.

[0047] Among them, the blast furnace slag and converter slag are sourced from Zhongtian Iron and Steel Group (Nantong) Co., Ltd.;

[0048] The oyster mushroom residue was collected from Lvya (Jiangsu) Edible Fungus Co., Ltd., and was used after being composted and decomposed.

[0049] Bacillus megater inoculum was obtained through commercial sales, and the product brand was Yeshengwang Biotechnology.

[0050] The Bacillus polymyxa inoculum agent was obtained through commercial sales, and the product brand was Yeshengwang Biotechnology.

[0051] Bacillus laterosporus inoculum is available commercially through the brand Yeshengwang Biotechnology.

[0052] The Bacillus amyloliquefaciens inoculum was obtained commercially from the brand Yeshengwang Biotechnology.

[0053] The Bacillus mucilaginosus inoculant was obtained commercially from the brand Yeshengwang Biotechnology.

[0054] Bacillus subtilis inoculant was obtained through commercial sales, and the product brand was Yeshengwang Biotechnology.

[0055] Bacillus licheniformis inoculant was obtained through commercial sales, and the product brand was Yeshengwang Biotechnology.

[0056] The Bacillus oryzae inoculant was provided by Hebei Mengbang Water-soluble Fertilizer Co., Ltd.

[0057] Evaluation indicators:

[0058] (1) Measurement of plant-related indicators:

[0059] Rhizome density: per unit area (dm²) 2 The total number of rhizomes of turfgrass in the area, and the number of tillers in each small plot per square decimeter;

[0060] Stolon growth rate: Four rhizomes were randomly selected from each treatment and marked. Their length was measured with a tape measure. The length was measured again after 10 days. The amount of stolon elongation per unit number of days was the stolon growth rate.

[0061] Leaf SPAD value: Ten leaves from each treatment were selected and measured using a SPAD meter during the morning or afternoon time period.

[0062] Dry weight of above-ground and underground parts, and root / shoot ratio: Remove all plants from the pots, wash them thoroughly with water, separate the above-ground and underground parts with scissors, place them in an oven at 105℃ for 30 minutes to blanch, and dry them at 80℃ until constant weight. Weigh the dry weight. The root-shoot ratio is the ratio of the fresh or dry weight of the underground part of the plant to the above-ground part.

[0063] Root morphology: Remove the entire bermudagrass plant, along with its soil, from the pot. Rinse thoroughly with plenty of water until no soil substrate remains in the roots. Select bermudagrass plants of similar growth and place them on a tray filled with clean water, ensuring the roots do not overlap as much as possible. Place the tray on an ImageScanner III root scanner, take clear pictures, and export them in JPG format. Import the root images into WinRhizo software, select the root area, and the software will automatically measure relevant root parameters.

[0064] Root activity: Lawn root activity was determined using the TTC method.

[0065] Determination of elemental content in the aboveground parts of the plant: Total phosphorus, total potassium, total silicon, total iron, total magnesium, total manganese, total zinc, total calcium and total sulfur in the aboveground parts of the plant were determined by ICP-OES (Agilent 710 ICP-OES inductively coupled plasma atomic emission spectrometer).

[0066] (2) Measurement of soil-related indicators:

[0067] a. Determination of rhizosphere soil enzyme activity:

[0068] Soil sucrase activity determination: Sucrase activity was determined using the 3,5-dinitrosalicylic acid colorimetric method, and expressed as the number of milligrams of glucose produced after 1 g of air-dried substrate was cultured at 37℃ for 24 h. Specific operational procedures were referenced in the "Soil Enzymes and Research Methods" compiled by Guan Songmeng et al.

[0069] Soil catalase activity assay:

[0070] Catalase activity was determined by potassium permanganate titration. 2 g of air-dried matrix was placed in a 100 mL Erlenmeyer flask, and 40 mL of distilled water and 5 mL of 0.3% H₂O₂ solution were added (a soil-free control was also included). After shaking for 20 min, 5 mL of 3 g·L H₂SO₄ was added to stabilize the undecomposed H₂O₂, and the solution was filtered through slow-speed filter paper. 25 mL of the filtrate was collected and titrated with 0.1 g / L potassium permanganate until a pale pink color was achieved. The amount of potassium permanganate consumed was calculated using a control without added soil. Catalase activity was expressed as the volume (mL) of 0.1 mol / L potassium permanganate consumed per g of air-dried matrix after 20 min. The catalase activity value was calculated using the formula:

[0071] M = (V1 - V2) × T / g;

[0072] M: Activity value;

[0073] V1: The mL value of 0.1 g / L potassium permanganate solution consumed by the sample;

[0074] V2: The value of the 0.1 g / L potassium permanganate solution consumed as a reference;

[0075] T: Correction value for 0.1 g / L potassium permanganate titration;

[0076] g: Sample weight.

[0077] Soil urease activity determination: Urease activity was determined using the indophenol blue colorimetric method, based on the ammonia nitrogen (NH4+) generated after 1 g of air-dried substrate was incubated at 37℃ for 24 h. 4+ The milligrams of H are used to represent the enzyme composition. For specific operational methods, refer to the "Soil Enzymes and Research Methods" compiled by Guan Songmeng et al.

[0078] b. Soil element content determination: Total phosphorus, total potassium, total silicon, total iron, total magnesium, total manganese, total zinc, total calcium, and total sulfur in the soil were determined by ICP-OES (Agilent 710 ICP-OES inductively coupled plasma atomic emission spectrometer).

[0079] Example 1

[0080] A method for promoting the growth of bermudagrass on steel slag beds based on microbial organic substrates, comprising the following steps:

[0081] S1: Bacillus powder was inoculated into an Erlenmeyer flask containing 100 mL of LB liquid medium and cultured with shaking at 37°C and 150 rpm for 24 h. The bacterial solution was then spread onto LB solid medium and cultured in the dark at 37°C for activation. Based on colony color and morphological characteristics, a single colony of the activated bacteria was picked and inoculated into LB liquid medium. After culturing with shaking at 28°C and 230 rpm for 24 h, the transmittance (T) of the bacterial solution was adjusted to 50% at λ=660 nm using a UV spectrophotometer. At this point, the viable bacterial concentration was approximately 1×10⁻⁶. 9 cfu / mL, to be used as stock solution for later use;

[0082] S2: Based on the recommended dosage and effective viable bacteria count stated in the product instructions, set a reasonable concentration gradient for the bacterial solution, as shown in Table 1. Calculate the required amount of each bacterial stock solution for 500g of composted mushroom residue based on the set concentration gradient (calculation method: required amount of bacterial stock solution per 500g composted mushroom residue = recommended concentration in table * 200mL / 1 * 10). 9 The bacterial stock solution of different treatment concentrations was prepared in 50mL centrifuge tubes. The stock solution was diluted to 200mL with sterile water and then added to 500g of air-dried bacterial residue in portions and mixed evenly. The bacteria were allowed to colonize on the organic substrate for 3 days, which became the microbial organic substrate used in the experiment.

[0083] S3: Take naturally air-dried converter slag (ordinary carbon steel converter slag, particle size range: 0.2~1.0mm, composition: CaO 43.72%; Fe2O3 24.19%; SiO2 14.00%; MgO 5.78%; P2O5 3.51%; MnO 3.21%; Al2O3 3.03%; TiO2 1.08%; others 1.48%) and fill it into a flowerpot with an inner diameter of 13cm and a height of 11cm, burying it to a height of 9cm along the inner edge of the flowerpot to simulate a pile of steel slag; then weigh 100g of the microbial organic matrix prepared in S2 and evenly cover it on the converter slag, for a total of 4 replicates; finally, bury 10g of shredded grass stems in the microbial organic matrix. After sowing the grass stems, water twice a day for the first 15 days and once a day for the next 14 days.

[0084] Observe the growth and spread of the lawn in the flowerpots once a week, and finally select the best lawns based on their appearance. Figures 10-17 As shown, four experimental treatments were selected that showed significantly better lawn appearance quality than the control: four treatments inoculated with 0.5 times the recommended concentration of Bacillus mucilaginosus, 4 times the recommended concentration of Bacillus polymyxa, 2 times the recommended concentration of Bacillus megaterium, and the recommended concentration of Bacillus aureus. Subsequent related index measurements were performed on these treatments and compared with the control group.

[0085] Table 1. Concentration gradient settings for different bacterial species

[0086]

[0087] Depend on Figure 1 It was found that inoculation with four different microbial agents significantly increased the rhizome density of Bermuda grass compared with the control group. Compared with the blank control, inoculation with Bacillus polymyxa, Bacillus mucilaginosus, Bacillus megaterium, and Bacillus aspergillus increased the rhizome density of Bermuda grass by 80%, 67%, 77%, and 80%, respectively. There was no significant difference among the different microbial fertilizers in their effects on the rhizome density of Bermuda grass.

[0088] Depend on Figure 2 It was found that the stolons treated with *Bacillus mucilaginosus* had the fastest expansion rate, while the stolons in the control group had the slowest expansion rate. The growth rate of the stolons treated with *Bacillus mucilaginosus* was significantly different from that of *Bacillus oryzae*, *Bacillus gigantii*, and the control group. The growth rate of the stolons treated with *Bacillus polymyxa* was significantly higher than that of *Bacillus gigantii* and the control group. The growth rate of the stolons treated with *Bacillus oryzae* was not significantly different from that of *Bacillus gigantii* and the control group. Therefore, the order of stolon growth rate from fastest to slowest is: *Bacillus mucilaginosus* > *Bacillus gigantii* > *Bacillus oryzae* > *Bacillus gigantii* > control.

[0089] SPAD values ​​can be used to assess the relative chlorophyll content in leaves, derived from... Figure 3 It can be seen that the SPAD value of the Bacillus polymyxa treatment group was the highest, while the SPAD value of the control group was the lowest. There were significant differences between Bacillus polymyxa, Bacillus aspergerii, and the control. There were no significant differences in the SPAD values ​​of leaves between the Bacillus megaterium and Bacillus mucilaginosus treatments and the Bacillus polymyxa treatment, and they were at the same level. There were no significant differences between the Bacillus aspergerii and Bacillus mucilaginosus treatments and the control group, indicating that their chlorophyll content did not change much compared with the control group.

[0090] Depend on Figure 4 It was found that there were significant differences in root surface area and total root volume among the different treatments. The Bacillus polymyxa treatment group had the largest root surface area, reaching 20.78 cm³. 2 The root surface area of ​​the *Bacillus polymyxa* treatment was significantly larger than that of the other treatments, increasing by 86.87% compared to the control group. Compared to the control group, the total root volume of the *Bacillus polymyxa* and *Bacillus megaterium* treatments increased by 88.89% and 77.78%, respectively. However, there was no significant difference in the total root volume between the two treatments and the other treatments.

[0091] Depend on Figure 5The results show the differences in aboveground and belowground dry weight and root-to-shoot ratio among different treatments. The aboveground dry weight of the *Bacillus macrocephala* and *Bacillus polymyxa* treatments was significantly higher than that of the two *Bacillus* treatments and the control group. The aboveground dry weight of the *Bacillus amyloliquefaciens* treatment showed no significant difference compared to the *Bacillus macrocephala*, *Bacillus polymyxa*, and the two *Bacillus* treatments, and was significantly higher than the control group. The aboveground dry weight of the two *Bacillus* treatment groups was not significantly different from the control group, remaining at the same level, with an aboveground dry weight range of 4.19 g to 4.62 g. Compared to the control group, the aboveground dry weight of the *Bacillus polymyxa* treatment group increased by 54%.

[0092] Regarding the dry weight of the underground parts, the treatment with *Bacillus mucilaginosus* yielded the highest dry weight, reaching 3.63 g. There was no significant difference in dry weight between the *Bacillus mucilaginosus* treatment and the treatments for giant, multi-mucilaginous, and *A. mucilaginosus*, but the dry weight was significantly higher than the control group. The order of dry weight of the underground parts from highest to lowest was: *Bacillus mucilaginosus*, giant, multi-mucilaginous, *A. mucilaginosus*, and control.

[0093] Depend on Figure 5 It can also be seen that the highest root-to-shoot ratio was observed in the Bacillus mucilaginosus treatment, reaching 0.8, which is significantly higher than the data from other treatment groups. The root-to-shoot ratios of the different treatment groups from left to right are: 0.55, 0.49, 0.54, 0.80, and 0.48.

[0094] Plant roots play a vital role in water absorption, nutrient uptake, support and anchoring for plant growth, soil interaction, storage and adaptation, and biodiversity maintenance. Understanding and studying the characteristics and functions of plant roots contributes to a deeper understanding of plant ecological adaptability, growth and development mechanisms, and the complexity of plant-soil interactions. Figure 6 As shown, the root activity of the Bacillus mucilaginosus treatment was significantly higher than that of other treatments. There was no significant difference in root activity among the three treatments of Bacillus amyloliquefaciens, Bacillus polymyxa, and Bacillus megaterium, and all of them were significantly higher than that of the control group.

[0095] Nutrients are essential components for plant growth and development, providing the energy and building materials needed for plant life. Plants absorb nutrients from the soil to synthesize proteins, nucleic acids, enzymes, and other important organic substances, thus achieving normal physiological functions. Furthermore, different nutrients play different roles in plant growth. For example, nitrogen, phosphorus, and potassium are considered major nutrients, promoting plant growth and development and regulating metabolic processes. Micronutrients such as iron, zinc, and manganese participate in enzyme activation and catalysis, maintaining normal metabolic reactions in plants. As shown in Table 2, there are significant differences in nutrient element content among the aboveground parts of plants under different treatments. The calcium content of the aboveground parts of plants under different treatments, from highest to lowest, is: sandy soil, giant soil, Alsaceous soil, multi-sticky soil, control, and gelatinous soil. Regarding total phosphorus content, the treatments inoculated with microbial agents showed a significant increase compared to the control group. The total phosphorus content of the control group plants was only 1.66 mg / kg, while the total phosphorus content of the experimental groups ranged from 1.93 mg / kg to 2.14 mg / kg. There was no significant difference in total phosphorus content between the sandy soil treatment and the treatment inoculated with microbial agents, but the total potassium content of the aboveground plants in the sandy soil treatment was significantly lower than that in other treatments. There was no significant difference in total potassium content among the three treatments (Gelatin, Polymerac, and Aspergillus), all at the same level above 16 mg / kg. There was no significant difference in iron content among the aboveground plants of different treatments. The Bacillus mucilaginosus treatment and the sandy soil treatment were in the first tier in terms of total magnesium content, while the Giant, Polymerac, and Aspergillus treatments were in the second tier. The control group had the lowest total magnesium content. Except for the control, the performance of each treatment in terms of total sulfur content was basically consistent with that in terms of total magnesium content. The control group had the lowest total magnesium content at 2.1 mg / kg, significantly lower than other treatments. Manganese content was very low in the aboveground plants of all treatments, ranging from 0.03 mg / kg to 0.07 mg / kg, still showing some variation. The zinc content was even lower. The total zinc content of plants in the sandy soil treatment was 0.05 mg / kg, which was significantly different from other treatments. The total zinc content of other treatments was around 0.03 mg / kg. Regarding total silicon content, the total silicon content of plants inoculated with Bacillus megaterium was significantly higher than other treatments, while the total silicon content of Bermuda grass plants grown in ordinary sandy soil was 1.86 mg / kg, significantly lower than other treatments, and 0.54 mg / kg lower than the Bacillus megaterium treatment group.

[0096] Table 2. Element content of aboveground plants under different treatments

[0097]

[0098] Depend on Figure 7It can be seen that the sucrase activity in the soil inoculated with *Bacillus polymyxa* was significantly higher than that in other treatments. The sucrase activity in the soil treated with *Bacillus amyloliquefaciens* showed a significant difference compared to the control group, but the increase was smaller. However, the sucrase activities in the soil treated with *Bacillus polymyxa*, *Bacillus mucilaginosus*, and *Bacillus megaterium* were significantly increased compared to the control group, increasing by 111.9%, 86.75%, and 86.44%, respectively. Sucrase, also known as sucrose invertase or sucrose lyase, is an important soil enzyme. It catalyzes the hydrolysis of sucrose, converting it into soluble sugar molecules that can be utilized by microorganisms and plants. These soluble sugar molecules have a significant impact on the growth and metabolism of soil microorganisms, providing energy and carbon sources. Studies have shown that the stronger the sucrase activity, the higher the soil fertility.

[0099] Depend on Figure 8 It can be seen that, compared with the control group, *Bacillus mucilaginosus*, *Bacillus polymyxa*, and *Bacillus megaterium* all significantly increased the activity of catalase in the soil. In terms of catalase activity, all four treatments showed an increase compared to the control group, with increases of 20.61%, 19.30%, 17.54%, and 8.77% respectively from left to right. Catalase plays an important role as a redox enzyme in the transformation of matter and energy in the soil. Excessive hydrogen peroxide in the soil can damage plants. Catalase is widely present in soil microorganisms, protecting plants from hydrogen peroxide toxicity.

[0100] Depend on Figure 9 It can be seen that the addition of microbial fertilizer can increase the urease activity in the lawn substrate. The urease activity in the soil treated with *Bacillus mucilaginosus*, *Bacillus megaterium*, and *Bacillus polymyxa* was significantly higher than that in the control group, while only the soil treated with *Bacillus amyloliquefaciens* showed lower urease activity than the control group. The NH3-N generated after 24 hours in the four treatments with higher urease activity ranged from 0.39 mg / g to 0.48 mg / g, representing increases of 62.5%, 100%, 95.8%, and 100% respectively compared to the control group. Urease is an enzyme found in many organisms, its main function being to catalyze the decomposition of urea into ammonia and carbon dioxide. Urease is ubiquitous in soil, plants, bacteria, and animals. This enzymatic reaction provides plants with a usable nitrogen source (ammonia), promoting plant growth and development. Simultaneously, urease also participates in a key step of the nitrogen cycle, converting organic nitrogen in urea into inorganic nitrogen, thus affecting the supply and utilization of nitrogen in the soil.

Claims

1. A method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix, characterized in that, The steps are as follows: S1: Inoculate Bacillus powder into an Erlenmeyer flask containing LB liquid medium, stir and incubate for 24 hours to obtain the initial culture solution; S2: Spread the initial bacterial culture obtained in S1 evenly onto an LB solid culture dish, then incubate the culture dish in the dark to activate it. Based on the color and morphological characteristics of the colonies, pick a single colony of the activated bacteria and inoculate it into LB liquid culture medium. After shaking culture for 24 hours, use a UV spectrophotometer at λ=660nm to adjust the transmittance of the bacterial culture to 50% and use it as the stock solution for later use. S3: Set a reasonable bacterial concentration gradient, calculate the amount of each bacterial stock solution required for a specific mass of composted bacterial residue, prepare it in centrifuge tubes, and dilute the bacterial stock solutions of different treatment concentrations to the standard mark with sterile water. Then add them to a specific mass of air-dried bacterial residue in portions and mix them evenly. Allow the bacterial strains to colonize on the organic substrate for 3 days to obtain the microbial organic substrate used in the experiment. S4: Take naturally dried converter slag and fill it into a flowerpot. Cover the surface of the converter slag evenly with the microbial organic matrix prepared in S3. Bury the torn Bermuda grass stems into the microbial organic matrix. Then, water twice a day for the first 15 days and once a day for the next 14 days. S5: Observe the growth and propagation of bermudagrass in the flower pots every week, and screen them based on the appearance of the lawn.

2. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S1, the viable count of Bacillus powder in the Erlenmeyer flask is 1×10⁻⁶. 11 The LB liquid culture medium is 100 mL.

3. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S1, the temperature for stirring and culturing is 37°C, and the stirring condition is 150 rpm.

4. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S1, the Bacillus is selected from one of Bacillus megaterium, Bacillus polymyxa, Bacillus laterosporus, Bacillus amyloliquefaciens, Bacillus mucilaginosus, Bacillus subtilis, and Bacillus licheniformis.

5. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S2, the method for picking activated bacteria is as follows: after the colony grows, use a sterilized inoculation loop near the flame of an alcohol lamp to scrape off a single activated colony that is growing vigorously, has neat edges, and is free from contamination by other bacteria, and quickly inoculate the inoculation loop into LB liquid culture medium.

6. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S2, the conditions for oscillation culture are 28℃ and 230rpm.

7. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In step S2, the concentration of viable bacteria in the stock solution is 1×10⁻⁶. 9 cfu / mL.

8. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S3, the bacterial concentration gradient is set as follows: 0.5x, recommended concentration, 2x, and 4x.

9. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In S4, the particle size of the converter slag is 0.2~1.0mm, and the sum of the contents of CaO and P2O5 in the converter slag exceeds 47%.

10. The method for promoting the growth of bermudagrass on a steel slag bed based on a microbial organic matrix according to claim 1, characterized in that, In step S4, the mass ratio of the microbial organic substrate to the shredded Bermuda grass stems is 10:1.

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