Composite biological rice seedling raising substrate and preparation method thereof

Abstract

The invention discloses a composite biological rice seedling raising substrate and a preparation method thereof, and belongs to preparation of rice seedling raising substrates. In order to solve the technical problems that in the prior art, a rice seedling raising substrate is unbalanced in nutrient and high in cost, the composite biological rice seedling raising substrate is provided and comprises a substrate mixture, a lactobacillus buchneri mixed bacterium solution and a seedling strengthening agent, and the substrate mixture comprises soil, biogas residues and biogas residue combustion residues. The composite biological rice seedling raising substrate provided by the invention realizes dual effects of optimizing a substrate microenvironment and inhibiting pathogenic bacteria, remarkably improves the rice emergence rate, protects cultivated land soil and digests organic wastes. Rice seedlings raised by using the substrate provided by the invention are neat and strong, have developed root systems and strong packing force, and have the advantages of protecting the ecological environment, saving the seedling raising cost and the like.

Description

Technical Field

[0001] This invention relates to the preparation of rice seedling substrates, and in particular to a composite biological rice seedling substrate and its preparation method. Background Technology

[0002] Rice is one of the most important food crops, and its cultivation process includes seedling raising, transplanting, and field management; among these, seedling raising is a crucial part of rice cultivation. Traditional rice seedling raising requires a large amount of seedling soil to provide nutrients for seedling growth. Soil collection leads to the destruction of large areas of the topsoil and the ecological environment, seriously affecting sustainable agricultural development. Therefore, developing a new type of rice seedling substrate that utilizes agricultural waste to reduce soil resource consumption while being rich in nutrients is of great significance.

[0003] Seedling substrate, also known as nursery medium or sowing medium, refers to artificially prepared materials used during the sowing and seedling stages of crops to provide the nutrients, water, and air necessary for seed germination and early seedling growth. Common seedling substrates in current technology mainly consist of the following substances: organic materials (peat moss / coconut coir), inorganic minerals (vermiculite / perlite), and nutrient fertilizers. Seedling substrates replace the role of natural soil, and are particularly important in modern agricultural production and hydroponics where precise control of growth conditions is required.

[0004] Biogas residue, a solid substance produced by the fermentation of organic matter, has advantages such as being rich in nutrients, having a loose and porous structure, facilitating resource recycling, and being inexpensive; however, it also has some problems such as unbalanced nutrients and insufficient decomposition. The residue after biogas residue combustion refers to the final product formed by minerals under high temperatures. It has advantages such as loose and porous particles, rich in mineral elements, and being inexpensive, but it also has some problems such as poor water retention and uneven particle size.

[0005] Therefore, those skilled in the art are eager to develop a rice seedling substrate that is nutrient-rich, has suitable acidity, is environmentally friendly, has a simple preparation process, and is inexpensive. Summary of the Invention

[0006] To address the technical problems of unbalanced nutrients and high costs in existing rice seedling substrates, this invention provides a composite biological rice seedling substrate and its preparation method.

[0007] One objective of this invention is to provide a composite biological rice seedling substrate, which comprises: a substrate mixture, a mixed bacterial solution of Lactobacillus bruneri, and a seedling strengthening agent; the Lactobacillus bruneri is Lactobacillus bruneri NEFU-1 and Lactobacillus bruneri NEFU-2; the mixed bacterial solution of Lactobacillus bruneri is obtained by mixing and inoculating Lactobacillus bruneri NEFU-1 and Lactobacillus bruneri NEFU-2 at an inoculation ratio of 1:1.

[0008] In a preferred embodiment of the present invention, the Lactobacillus baumannii NEFU-1 has the accession number CCTCC NO: M20241206 and is classified as follows: Lactobacillus buchneri NEFU-1, deposited at the China Center for Type Culture Collection, on June 13, 2024; The Lactobacillus brunetti NEFU-2 described herein has the accession number CCTCC NO: M 20241207 and is classified as follows: Lactobacillus buchneri NEFU-2 is deposited at the China Center for Type Culture Collection on June 13, 2024.

[0009] In a preferred embodiment of the present invention, the matrix mixture is obtained by mixing soil, biogas residue and biogas residue combustion residue in a volume ratio of 20:(50-70):(30-10).

[0010] In a preferred embodiment of the present invention, the biogas residue is obtained by mixing fresh cow dung and straw in a volume ratio of 4:1 and then anaerobic fermenting it.

[0011] In a preferred embodiment of the present invention, the volume ratio of the substrate mixture to the seedling strengthener is 1:140.

[0012] The second objective of this invention is to provide a method for preparing the above-mentioned composite biological rice seedling substrate, the preparation method comprising the following steps: S1: Mix Lactobacillus NEFU-1 and Lactobacillus NEFU-2 at a 1:1 inoculation ratio and inoculate them into the culture medium for fermentation culture to obtain a mixed Lactobacillus NEFU-2 culture. S2: Mix the pretreated soil, biogas residue and biogas residue combustion residue in a volume ratio of 20:(50-70):(30-10) to obtain a substrate mixture. Mix the above substrate mixture with the seedling strengthening agent in a volume ratio of 1:140 to obtain a mixture. S3: Place the mixture obtained in S2 into seedling trays, at a ratio of 0.004 m... 3 The mixed bacterial solution of Lactobacillus bryonicus obtained in S1 was poured into the soil to obtain a composite rice seedling substrate with a pH < 6.

[0013] In a preferred embodiment of the present invention, the culture medium in S1 is MRS culture medium.

[0014] In a preferred embodiment of the present invention, the fermentation conditions described in S1 are: 30°C, 180 r / min shaking culture for 72 h.

[0015] In a preferred embodiment of the present invention, the pretreatment step in S2 is as follows: air-drying the soil, biogas residue and biogas residue combustion residue, crushing them through a 2 mm sieve, and adjusting the pH value to 4.5-5.5 using sulfuric acid.

[0016] The third objective of this invention is to provide the application of the above-mentioned composite biological rice seedling substrate in rice cultivation.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a composite biological rice seedling substrate, the composite biological rice seedling substrate comprising: a substrate mixture, a mixed bacterial solution of Lactobacillus bruneri, and a seedling strengthening agent; the substrate mixture comprises: soil, biogas residue, and biogas residue combustion residue; the mixed bacterial solution of Lactobacillus bruneri comprises: Lactobacillus bruneri NEFU-1 and Lactobacillus bruneri NEFU-2 bacterial solutions.

[0018] Compared to existing technologies, this invention introduces a specific proportion of Lactobacillus bromide mixed bacterial solution into the rice seedling substrate. By maintaining the pH of the composite rice seedling substrate < 6, it achieves the dual effects of optimizing the substrate microenvironment (acidity) and inhibiting pathogens during the seedling raising process. Based on the acidity and alkalinity requirements of rice seedlings, lactic acid is produced by the proliferation of Lactobacillus bromide during the seedling raising process, maintaining the pH value of the substrate at a constant acidity. This avoids the decrease in substrate acidity, prevents the occurrence of rice damping-off disease, and also saves the step of lowering the pH by watering with acidic water in the conventional seedling raising process.

[0019] Compared with existing technologies, the biogas residue used in this invention is prepared by mixing and composting cow dung and rice straw. This not only achieves the harmless treatment of cow dung and the effective utilization of rice straw, but also the harmless treatment of the residue after biogas residue combustion and the effective utilization of biogas residue, providing an effective way to solve the problem of agricultural waste polluting the environment.

[0020] Soil collection leads to the destruction of large areas of topsoil and the ecological environment, seriously affecting sustainable agricultural development. The composite biological rice seedling substrate provided by this invention reduces the use of soil resources and solves the problems of difficult soil collection and high labor costs in factory-style rice seedling production, effectively promoting the development of green and sustainable seedling technology. It is evident that the seedling substrate provided by this invention significantly improves rice seedling emergence rate while simultaneously protecting arable land, disposing of organic waste, protecting the ecological environment, and reducing seedling costs. Attached Figure Description

[0021] Figure 1 This is a graph showing the results of the homology comparison analysis in Example 1; Figure 2 The OD of the mixed bacterial culture of Lactobacillus bruneri in Example 2 600 And pH change curve; a is OD 600The graph shows the pH change curve; b is the pH change curve. Figure 3 This is a diagram showing the inhibitory effect of the mixed bacterial suspension of Lactobacillus brunelli on pathogens in Example 2. a is Fusarium oxysporum, b is Fusarium solani, and c is rice false smut. Each group, from left to right, is the control group and experimental groups 1-3. Figure 4 The diagram shows different formulations of rice seedling substrates; a is soil, b is composite biological rice seedling substrate 1, c is composite biological rice seedling substrate 2, and d is composite biological rice seedling substrate 3. Figure 5 Diagrams showing rice seedling raising and sowing with different formulations of seedling raising substrates; a represents soil, b represents composite biological rice seedling raising substrate 1, c represents composite biological rice seedling raising substrate 2, and d represents composite biological rice seedling raising substrate 3. Figure 6 Figure 1 shows the growth of rice 12 days after sowing in different formulations of seedling substrate; a is soil, b is composite biological rice seedling substrate 1, c is composite biological rice seedling substrate 2, and d is composite biological rice seedling substrate 3. Figure 7 Figure 3 shows the growth of rice 30 days after sowing in different formulations of seedling substrate; a is soil, b is composite biological rice seedling substrate 1, c is composite biological rice seedling substrate 2, and d is composite biological rice seedling substrate 3. Figure 8 Figure 1 shows the growth of rice 38 days after sowing in different formulations of rice seedling substrates; a is soil, b is composite biological rice seedling substrate 1, c is composite biological rice seedling substrate 2, and d is composite biological rice seedling substrate 3. Detailed Implementation

[0022] Those skilled in the art can refer to the content of this document and appropriately improve the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content and scope of this invention to implement and apply the technology of this invention.

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0024] The seedling strengthening agent used in the following examples was purchased from Nantong Qifeng Fertilizer Technology Co., Ltd. (Agricultural Registration Certificate No. Gui Nong Fei (2015) Zhun Zi 2282); 30% metalaxyl-mancozeb was purchased from Shandong Lvdedi Biotechnology Co., Ltd. (Agricultural Registration Certificate No. PD20161297); Fusarium oxysporum, Fusarium solanum, and rice false smut were prepared by the laboratory.

[0025] The Lactobacillus Brucella used in the following examples is Lactobacillus Brucella NEFU-1, with accession number CCTCC NO: M20241206, and classified as follows: Lactobacillus buchneri NEFU-1 It is deposited at the China Center for Type Culture Collection on June 20, 2024.

[0026] Lactobacillus brunetti NEFU-2, accession number CCTCC NO: M 20241207, classified and named as follows: Lactobacillus buchneri NEFU-2 It is deposited at the China Center for Type Culture Collection on June 20, 2024.

[0027] Example 1: Isolation, screening and identification of lactic acid bacteria (1) Isolation and screening of lactic acid bacteria: Yanji pickled vegetables were selected as samples and diluted. They were spread on MRS solid medium plates (52.24 g of MRS broth and 10 g-20 g of agar powder were dissolved in 1 L of distilled water and sterilized at 121℃ for 20 min). The plates were left to stand and incubated at 37℃ for 48 h. Colonies that were milky white were selected and single colonies with typical lactobacillus characteristics were obtained. The single colonies were repeatedly streaked on MRS solid medium plates for purification until single-morphological colonies appeared. The colonies obtained were inoculated into liquid MRS medium to obtain two lactic acid bacteria strains that could grow in liquid MRS medium.

[0028] (2) Identification of lactic acid bacteria: DNA of the lactic acid bacteria strain obtained in (1) was extracted using a bacterial genomic DNA extraction kit, and PCR amplification was performed using universal primers 27F (nucleotide sequence shown in SEQ ID NO.1) and 1492R (nucleotide sequence shown in SEQ ID NO.2); the PCR amplification reaction system was: 1 μL of genomic DNA (20 ng / μL), 10× Buffer (containing 2.5 mM Mg 2+5 μL of Taq polymerase (5 u / μL), 1 μL of dNTP (10 mM), 1.5 μL each of primers 27F and 1492R (10 μM), and ddH2O to a final volume of 50 μL were added. The PCR amplification program was as follows: pre-denaturation at 95℃ for 5 min; denaturation at 95℃ for 30 s, annealing at 58℃ for 30 s, extension at 72℃ for 1.5 min, for 35 cycles; final extension at 72℃ for 7 min. The PCR amplification products were recovered using the AxyPrep DNA gel extraction kit and sent to Shanghai Paisennong Biotechnology Co., Ltd. for sequencing. The obtained sequences were compared with the GenBank database using BLAST software for homology analysis. The results are as follows. Figure 1 As shown, the two lactic acid bacteria strains obtained from the above screening were identified as Lactobacillus bruneri, and named NEFU-1 and NEFU-2, respectively; the 16S rRNA of Lactobacillus bruneri NEFU-1 is shown in SEQ ID NO.3, and the 16S rRNA of Lactobacillus bruneri NEFU-2 is shown in SEQ ID NO.4.

[0029] Example 2: Preparation of Lactobacillus brunelli mixed bacterial culture The Lactobacillus Brügel's NEFU-1 and Lactobacillus Brügel's NEFU-2 obtained in Example 1 were inoculated into MRS medium at a ratio of 1:1 and cultured at 30°C for 72 h to obtain a mixed culture of Lactobacillus Brügel's.

[0030] Meanwhile, a Control group was set up: MRS medium was not inoculated with Lactobacillus buchneri and cultured at 30°C for 72 h.

[0031] The OD values ​​of the above-obtained Lactobacillus bromide mixed culture and the Control group were measured during the culture process. 600 And pH changes, the results are as follows Figure 2 As shown, the OD values ​​of *Lactobacillus bruneri* NEFU-1 and *Lactobacillus bruneri* NEFU-2 after culturing at 30℃ for 72 h were... 600 The pH of the mixed bacterial solution showed an upward trend, while the pH of the solution decreased to 4. It is speculated that this is because Lactobacillus brunelli produces organic acids (such as lactic acid) during its metabolism, which leads to a significant decrease in the pH of the culture medium.

[0032] Effect Experiment: The obtained Lactobacillus bruneri mixed bacterial culture was centrifuged at 8000 rpm for 20 min, the precipitate (bacterial cells) was discarded, and the supernatant was retained. The supernatant was filtered through a 0.22 μm filter membrane to completely remove residual Lactobacillus bruneri and ensure that the supernatant was sterile.

[0033] Experimental group: Colonies of Fusarium oxysporum, Fusarium solanum, and rice false smut were picked and inoculated into the supernatant of the filtered Lactobacillus brunelli mixed bacterial solution, and the experiment was repeated 3 times; Control group: No pathogens were inoculated, i.e., the supernatant of the sterile Lactobacillus brunelli mixed bacterial solution was used; The experimental group and the control group were incubated at 30℃ for 48 h, and the growth of pathogens was observed.

[0034] The results are as follows Figure 3 As shown, in the experimental group (pH=4 supernatant), *Fusarium oxysporum*, *Fusarium solanum*, and *Syngonium argentea* did not grow, showing no visible hyphae or spore germination, and were no different from the control group. The *Lactobacillus brunelli* mixed bacterial solution provided by this invention lowers the environmental pH to 4 through acid production. The optimal growth pH for *Fusarium oxysporum*, *Fusarium solanum*, and *Syngonium argentea* is neutral. An acidic environment disrupts the cell membrane stability, enzyme activity, and physiological functions of neutral pathogenic fungi, thereby inhibiting their growth.

[0035] It is evident that the Lactobacillus bryonicus mixed bacterial solution provided by this invention can significantly inhibit the growth of neutral pathogenic fungi, possesses biological disinfection potential, and can be used in agriculture or the food industry to prevent and control diseases caused by pathogenic fungi such as Fusarium.

[0036] Example 3: Preparation of a composite biological rice seedling substrate S1: Lactobacillus NEFU-1 and Lactobacillus NEFU-2 were mixed at an inoculation ratio of 1:1 and inoculated into MRS medium for fermentation culture (cultured at 30℃, 180 r / min full temperature shaker for 72 h). The inoculation amount was 1%, and a mixed bacterial culture of Lactobacillus NEFU-1 was obtained. S2: The pretreated soil, biogas residue, and biogas residue combustion residue are mixed at a volume ratio of 20:50:30 to obtain a matrix mixture. The matrix mixture is then mixed with a seedling strengthening agent at a volume ratio of 1:140 to obtain a mixture. The biogas residue is obtained by anaerobic fermentation of fresh cow manure and straw at a volume ratio of 4:1. The straw is rice straw, which is naturally decomposed for 60 days. The pretreatment steps are as follows: the soil, biogas residue, and biogas residue combustion residue are air-dried, crushed and passed through a 2mm sieve, and the pH value is adjusted to 4.5-5.5 using sulfuric acid. S3: The mixture obtained in S2 is spread on the seedling trays, the size of which is 58 cm × 28 cm × 2.5 cm. The thickness of the mixture in each tray is 1.5-2 cm. Before sowing, the mixture is thoroughly watered, and then 5 mL of the Lactobacillus bryonicus mixed bacterial solution obtained in S1 is poured in to obtain composite rice seedling substrate 1. The pH of the composite rice seedling substrate is <6.

[0037] Example 4: Preparation of a composite biological rice seedling substrate S1: Lactobacillus NEFU-1 and Lactobacillus NEFU-2 were mixed at an inoculation ratio of 1:1 and inoculated into MRS medium for fermentation culture (cultured at 30℃, 180 r / min full temperature shaker for 72 h). The inoculation amount was 1%, and a mixed bacterial culture of Lactobacillus NEFU-1 was obtained. S2: The pretreated soil, biogas residue, and biogas residue combustion residue are mixed at a volume ratio of 20:60:20 to obtain a matrix mixture. The matrix mixture is then mixed with a seedling strengthening agent at a volume ratio of 1:140 to obtain a mixture. The biogas residue is obtained by anaerobic fermentation of fresh cow manure and straw at a volume ratio of 4:1. The straw is rice straw, which is naturally decomposed for 60 days. The pretreatment steps are as follows: the soil, biogas residue, and biogas residue combustion residue are air-dried, crushed and passed through a 2mm sieve, and the pH value is adjusted to 4.5-5.5 using sulfuric acid. S3: The mixture obtained in S2 is spread on the seedling trays, the size of which is 58 cm × 28 cm × 2.5 cm. The thickness of the mixture in each tray is 1.5-2 cm. Before sowing, the mixture is thoroughly watered, and then 5 mL of the Lactobacillus bryonicus mixed bacterial solution obtained in S1 is poured in to obtain composite rice seedling substrate 2. The pH of the composite rice seedling substrate is <6.

[0038] Example 5: Preparation of a composite biological rice seedling substrate S1: Lactobacillus NEFU-1 and Lactobacillus NEFU-2 were mixed at an inoculation ratio of 1:1 and inoculated into MRS medium for fermentation culture (cultured at 30℃, 180 r / min full temperature shaker for 72 h). The inoculation amount was 1%, and a mixed bacterial culture of Lactobacillus NEFU-1 was obtained. S2: The pretreated soil, biogas residue, and biogas residue combustion residue are mixed at a volume ratio of 20:70:10 to obtain a matrix mixture. The matrix mixture is then mixed with a seedling strengthening agent at a volume ratio of 1:140 to obtain a mixture. The biogas residue is obtained by anaerobic fermentation of fresh cow manure and straw at a volume ratio of 4:1. The straw is rice straw, which is naturally decomposed for 60 days. The pretreatment steps are as follows: the soil, biogas residue, and biogas residue combustion residue are air-dried, crushed and passed through a 2mm sieve, and the pH value is adjusted to 4.5-5.5 using sulfuric acid. S3: The mixture obtained in S2 is spread on the seedling trays, the size of which is 58 cm × 28 cm × 2.5 cm. The thickness of the mixture in each tray is 1.5-2 cm. Before sowing, the mixture is thoroughly watered, and then 5 mL of the Lactobacillus bryonicus mixed bacterial solution obtained in S1 is poured in to obtain composite rice seedling substrate 3. The pH of the composite rice seedling substrate is <6.

[0039] Effect Experiment: 1. Using the composite rice seedling substrates 1-3 prepared in Examples 3, 4, and 5 as experimental groups and normal soil as the control group, rice seedlings were sown in each group. The specific steps are as follows: (1) Sowing and covering: Sow 120 g evenly in the seedling trays with the substrate laid out, cover with soil to a thickness of 0.5 cm, cover with mulch film, and remove the mulch film in time when the seedlings emerge and turn green. (2) Seedbed management: ①Temperature management: Seal and keep warm from sowing to emergence, controlling the temperature at 30-32℃; control the temperature at 25-28℃ during the one-leaf-one-heart stage, and start ventilation to harden the seedlings; increase ventilation during the two-leaf-one-heart stage, and control the temperature at 22-25℃; control the temperature at 20℃ after the three-leaf-one-heart stage; control the night temperature above 7℃. ②Water management: Check every 2 days from sowing to emergence. Water seedling trays that show signs of drying out using a micro-sprinkler to keep the seedbed moist but without significant water accumulation. Replenish water when seedlings are short of water during the seedling stage. ③ Topdressing in the seedbed: When the seedlings have one leaf and one heart stage, apply a seedling strengthening agent at 85 g / m². 2 Apply evenly to avoid localized pesticide damage; ④ Prevention of damping-off: When the seedlings are at the two-leaf stage, irrigate each square meter with 1.0-2.0 grams of 30% metalaxyl-mancozeb diluted in 1-1.5 liters of water.

[0040] like Figure 4 For different seedling substrate formulations, such as Figure 5 Diagrams showing rice seedling raising and sowing with different seedling substrate formulations, such as... Figure 6 The image shows the growth of rice 12 days after sowing. Using the seedling substrate provided by this invention for rice seedling cultivation can effectively improve seedling quality and promote seedling growth. The composite rice seedling substrate provided by this invention can achieve a rice emergence rate of 96%, which is significantly higher than the rice emergence rate of conventional seedling substrates (90.5%). The composite rice seedling substrate provided by this invention has a significant advantage in emergence rate.

[0041] 2. Field experiments of this invention were conducted in Tailai County, Qiqihar City, Heilongjiang Province. The composite rice seedling substrates 1-3 prepared using Examples 3, 4 and 5 were used as experimental groups, and normal soil was used as the control group. Large-scale field experiments were conducted on each group.

[0042] like Figure 7 As shown in the figure, rice seedlings were sown on different formula rice seedling substrates. From the growth demonstration picture 30 days after sowing, it can be seen that the rice seedlings sown using the composite biological rice seedling substrate provided by the present invention grew vigorously, uniformly, and without yellow leaves, disease spots or excessive growth.

[0043] like Figure 8As shown in Table 1, rice seedlings were sown on different formulations of rice seedling substrates. From the root system diagram and the statistical results of total root length, root surface area, and root coefficient 38 days after sowing, it can be seen that the rice seedlings sown using the composite biological rice seedling substrate provided by this invention have well-developed root systems, dense white roots, and the roots are firmly intertwined with the substrate, without any loosening of the seedlings.

[0044] Table 1

[0045] The specific embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A composite biological rice seedling substrate, characterized in that, The composite biological rice seedling substrate includes: a substrate mixture, a mixed bacterial solution of Lactobacillus bruneri, and a seedling strengthening agent; the Lactobacillus bruneri is Lactobacillus bruneri NEFU-1 and Lactobacillus bruneri NEFU-2; the mixed bacterial solution of Lactobacillus bruneri is obtained by mixing and inoculating Lactobacillus bruneri NEFU-1 and Lactobacillus bruneri NEFU-2 at an inoculation ratio of 1:

1.

2. The composite biological rice seedling substrate according to claim 1, characterized in that, The Lactobacillus brunetti NEFU-1 described herein has the accession number CCTCC NO: M 20241206 and is classified as follows: Lactobacillus buchneri NEFU-1, deposited at the China Center for Type Culture Collection, on June 20, 2024; The Lactobacillus brunetti NEFU-2 described herein has the accession number CCTCC NO: M 20241207 and is classified as follows: Lactobacillus buchneri NEFU-2 is deposited at the China Center for Type Culture Collection on June 20, 2024.

3. The composite biological rice seedling substrate according to claim 1, characterized in that, The matrix mixture is obtained by mixing soil, biogas residue and biogas residue combustion residue in a volume ratio of 20:(50-70):(30-10).

4. The composite biological rice seedling substrate according to claim 3, characterized in that, The biogas residue is obtained by mixing fresh cow dung and straw in a volume ratio of 4:1 and then anaerobic fermenting it.

5. The composite biological rice seedling substrate according to claim 1, characterized in that, The volume ratio of the substrate mixture to the seedling strengthener is 1:

140.

6. The method for preparing the composite biological rice seedling substrate according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: S1: Mix Lactobacillus NEFU-1 and Lactobacillus NEFU-2 at a 1:1 inoculation ratio and inoculate them into the culture medium for fermentation culture to obtain a mixed Lactobacillus NEFU-2 culture. S2: Mix the pretreated soil, biogas residue and biogas residue combustion residue in a volume ratio of 20:(50-70):(30-10) to obtain a substrate mixture. Mix the above substrate mixture with the seedling strengthening agent in a volume ratio of 1:140 to obtain a mixture. S3: Place the mixture obtained in S2 into seedling trays, at a ratio of 0.004 m... 3 The mixed bacterial solution of Lactobacillus bryonicus obtained in S1 was poured into the soil to obtain a composite rice seedling substrate with a pH < 6.

7. The preparation method according to claim 6, characterized in that, The culture medium described in S1 is MRS culture medium.

8. The preparation method according to claim 6, characterized in that, The fermentation conditions described in S1 are: 30℃, 180 r / min shaking culture for 72 h.

9. The preparation method according to claim 6, characterized in that, The pretreatment steps described in S2 are as follows: air-dry the soil, biogas residue and biogas residue combustion residue, crush them through a 2 mm sieve, and adjust the pH value to 4.5-5.5 using sulfuric acid.

10. The application of the composite biological rice seedling substrate according to any one of claims 1-5 in rice cultivation.

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