Strain for effectively improving saline alkali soil and application thereof

Abstract

The invention relates to the technical field of new strains, and provides a new strain which is screened from Xinjiang saline-alkali soil, is classified and named as sphingomonas sp. And is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCCNO.32220. Research finds that the strain can remarkably reduce the soil conductivity, the exchangeable sodium content, the alkalization degree and the total salt content, so that the soil quality is improved. The organic matter content and the acid phosphatase activity of the soil are remarkably improved, and the quality of the saline-alkali soil can be efficiently improved. Meanwhile, the invention provides a compound bacterial fertilizer for effectively improving saline-alkali soil, the compound bacterial fertilizer comprises bacillus subtilis, Exiguobacterium acetylbacter, Bacillus velezensis, Pseudomonas fluorescens, Rhodococcus capsulatus and a new strain Sphingomonas sp., and research finds that compared with a single bacterial solution, the compound bacterial solution has a more prominent remediation effect on saline-alkali soil.

Description

Technical Field

[0001] The invention relates to the technical field of new bacterial strains, and in particular to a bacterial strain for effectively improving saline-alkali soil and application thereof. Background Art

[0002] Soil is the basic means of production for agricultural development, and the quality of soil directly affects the healthy development of agriculture. Soil salinization is a common problem in the world, and its main manifestation is that soluble salts are constantly precipitated and accumulated on the soil surface. At present, the area of ​​soil salinization is still increasing, which seriously restricts agricultural production and economic development. Since saline-alkali soil contains a large amount of salt, it will destroy the balance of soil water and change the structure of the soil, causing the soil permeability to weaken, the permeability to increase, and it is easy to become compacted and sticky, and the soil fertility will decrease, affecting the normal growth of crops.

[0003] In recent years, the research method of using microorganisms to improve saline-alkali soil has attracted more and more attention. Biological bacteria come from nature, do not cause pollution to the environment, and can reproduce quickly to improve soil fertility; through the continuous action of biological bacteria, the quality of saline-alkali soil can be gradually improved to achieve sustainable development.

[0004] Therefore, developing a strain of bacteria that can effectively improve saline-alkali soil is of great significance to agricultural development. Summary of the invention

[0005] The purpose of the present invention is to provide a strain and application thereof for effectively improving saline-alkali soil in view of the problems existing in the prior art. The strain is classified and named as Sphingomonas sp., and is deposited in the China General Microbiological Culture Collection Center with a deposit number of CGMCC NO.32220. The strain can effectively improve the quality of saline-alkali soil. It can significantly reduce soil electrical conductivity, exchangeable sodium content, alkalinity and total salt content, and significantly increase soil organic matter content and acid phosphatase activity, achieving unexpected results.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A bacterial strain for effectively improving saline-alkali soil is classified and named as Sphingomonas sp. and is deposited in the China General Microbiological Culture Collection Center with a deposit number of CGMCC NO.32220.

[0008] The invention provides a new bacterial strain screened from saline-alkali land in Xinjiang, which is classified and named as Sphingomonas sp., and is preserved in the China General Microbiological Culture Collection Center with a preservation number of CGMCC NO.32220. Studies have shown that the bacteria can significantly reduce soil electrical conductivity, exchangeable sodium content, alkalinity and total salt content, significantly increase soil organic matter content and acid phosphatase activity, and can relatively efficiently improve the quality of saline-alkali soil, achieving unexpected results.

[0009] Furthermore, the deposit date of Sphingomonas sp. is October 15, 2024. The deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0010] A bacterial agent comprises bacterial strains which are effective in improving saline-alkali soil.

[0011] Furthermore, the bacterial agent is at least one of a solid bacterial agent, a liquid bacterial agent and a gel bacterial agent.

[0012] The application of the above-mentioned bacteria strains that are effective in improving saline-alkali soil in the preparation of saline-alkali soil improved products.

[0013] Furthermore, the product is at least one of a biological agent, a biological pesticide and a biological fertilizer.

[0014] A composite bacterial fertilizer for effectively improving saline-alkali soil comprises Bacillus subtilis, Exiguobacterium acetylicum, Bacillus velez, Pseudomonas fluorescens, Rhodococcus capsulatus and the above-mentioned bacterial species Sphingomonas sp. for effectively improving saline-alkali soil.

[0015] Studies have found that compared with single bacterial solution, composite bacterial solution is more effective in repairing saline-alkali land.

[0016] Further, the volume ratio of Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas sp. is 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2;

[0017] Preferably, the volume ratio of Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas sp. is 1:1:1:1:1:1:1.

[0018] and / or, the number of each bacterium is not less than 2.0×10 9 CFU / mL.

[0019] A method for preparing the above-mentioned composite bacterial fertilizer for effectively improving saline-alkali soil comprises the following steps:

[0020] Step 1, placing Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas sp. in culture medium respectively, shaking at constant temperature, to obtain six bacterial liquids;

[0021] Step 2, centrifuging the six bacterial solutions obtained in step 1 respectively to obtain six bacterial cells;

[0022] Step 3: dilute the six bacterial cells obtained in step 2 with sterile distilled water, then mix the six diluted bacterial solutions, and adjust the volume with sterile distilled water to obtain a composite bacterial fertilizer.

[0023] The invention relates to an application of the above-mentioned composite bacterial fertilizer for effectively improving saline-alkali soil in improving saline-alkali land.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. The present invention provides a new strain screened from saline-alkali land in Xinjiang, which is classified and named Sphingomonas sp. and preserved in the China General Microbiological Culture Collection Center with a preservation number of CGMCC NO.32220. Studies have found that the strain can significantly reduce soil conductivity, exchangeable sodium content, alkalinity and total salt content, significantly increase soil organic matter content and acid phosphatase activity, and can more efficiently improve the quality of saline-alkali soil, achieving unexpected results.

[0026] 2. The present invention provides a composite bacterial fertilizer for effectively improving saline-alkali soil, including Bacillus subtilis, Exiguobacterium acetylicum, Bacillus velez, Pseudomonas fluorescens, Rhodococcus capsulatus and a new bacterial species Sphingomonas sp. Studies have found that the composite bacterial solution has a more prominent effect on improving saline-alkali land than a single bacterial solution.

[0027] 3. The present invention provides a compound bacterial fertilizer for effectively improving saline-alkali soil, which can significantly reduce the total salt content and alkalinity of the soil; can significantly increase the content of soil organic matter, reduced nitrogen, available phosphorus and available potassium; at the same time, can significantly increase the activity of urease, acid phosphatase, sucrase and peroxidase in the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a morphological diagram of the colonies on the culture medium to screen out the strains.

[0029] Figure 2 This is a comparison chart of soil pH performance of each treatment after using the composite microbial solution for 40 days.

[0030] Figure 3 This is a comparison chart of soil conductivity performance of each treatment after using the composite microbial solution for 40 days.

[0031] Figure 4 This is a comparison chart of soil exchangeable sodium content performance of each treatment after using the composite microbial solution for 40 days.

[0032] Figure 5 This is a comparison chart of soil cation exchange capacity performance of each treatment after using the composite microbial solution for 40 days.

[0033] Figure 6 This is a comparison chart of soil alkalinity performance of each treatment after using the composite microbial solution for 40 days.

[0034] Figure 7 This is a comparison chart of the total salt content of the soil in each treatment after 40 days of using the composite microbial solution.

[0035] Figure 8 This is a comparison chart of soil organic matter content performance of each treatment after using the composite microbial solution for 40 days.

[0036] Fig. 9 This is a comparison chart of soil alkaline nitrogen content performance of each treatment after using the composite microbial solution for 40 days.

[0037] Fig.10 This is a comparison chart of the soil available phosphorus content in each treatment after 40 days of using the composite microbial solution.

[0038] Fig.11 This is a comparison chart of the soil available potassium content in each treatment after 40 days of using the composite microbial solution.

[0039] Fig.12 This is a comparison chart of soil sucrase activity performance of each treatment after using the composite microbial solution for 40 days.

[0040] Fig.13 This is a comparison chart of soil acid phosphatase activity performance of each treatment after using the composite microbial solution for 40 days.

[0041] Fig.14 This is a comparison chart of soil urease activity performance of each treatment after using the composite microbial solution for 40 days.

[0042] Fig.15 This is a comparison chart of soil peroxidase activity performance in each treatment after using the composite microbial solution for 40 days.

[0043] Fig.16 This is a comparison chart of soil catalase activity performance in each treatment after 40 days of using the composite microbial solution. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, but unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0047] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0048] The terms "including" and "having" in the specification and claims of the present application and any modifications thereof are open expressions, that is, including the contents specified in the present application but not excluding other contents.

[0049] In the description of this application, regardless of whether the words "about" or "approximately" are used, all the numbers disclosed herein are approximate values. The value of each number may differ by less than 10% or a reasonable difference considered by those skilled in the art, such as 1%, 2%, 3%, 4% or 5%.

[0050] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0051] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. "First feature" and "second feature" may include one or more of the features.

[0052] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0053] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0054] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0055] Example 1

[0056] Strain isolation and purification

[0057] The strain was isolated from saline-alkali soil in Bayingol Prefecture, Xinjiang.

[0058] High-salt and high-alkaline Luria-Bertani (LB) liquid medium: 5 g / L yeast extract, 10 g / L tryptone, 10 g / L NaCl, pH 9.0, used for routine microbial culture (adjust the pH to 9.0 using 40% NaOH).

[0059] Solid culture medium: yeast extract 5 g / L, tryptone 10 g / L, NaCl 10 g / L, pH 9.0, agar powder 20 g.

[0060] First, 10 g of soil sample was weighed and added into a triangular flask containing 90 mL of 0.9% sterile saline and a small amount of glass beads. After shaking at 180 rpm for 20 min, gradient dilution was performed to obtain 10 –1 , 10 –2 , 10 –3 , 10 –4 Suspension with concentration gradient. Take 20 μL of appropriately diluted gradient sample and spread it on high-salt and high-alkali LB medium plate. Place it in a 30℃ incubator for 2 days. After a single colony grows, pick a single colony for streaking culture, and obtain a pure strain by repeated streaking. Then put the pure strain in a 4℃ refrigerator for temporary experimental use. For long-term storage, add the bacterial solution to 50% glycerol at a ratio of 1:1 and store it at -80℃.

[0061] Screening of salt-alkali tolerant microbial strains and determination of salt-alkali tolerance

[0062] The screening of salt-alkali tolerant microbial strains is carried out by continuously increasing the salinity of the high-salt and high-alkali LB medium. First, the pH value of the high-salt and high-alkali LB medium is maintained at 9.0, and the salinity of the medium is gradually increased by 2%, so that the NaCl concentration is 10%, 12%, 14%, 16%, 18% and 20% respectively. The strains preserved on the high-salt and high-alkali solid LB medium are inoculated on the above-mentioned plate and cultured at 30°C for 2 days. Whether the strain can grow out is used as the standard for judging whether the strain is salt-alkali tolerant, thereby screening out strains with salt-alkali tolerant ability.

[0063] Screen the strains with colonies on the culture medium as follows Figure 1 As shown, it is milky white, has neat edges, is sticky, has a smooth surface, is easily separated from the culture medium, and has a medium colony size.

[0064] The 16S rDNA gene fragment was amplified from genomic DNA using bacterial universal primers 27F (SEQ ID No. 1: 5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (SEQ ID No. 2: 5'-GGTTACCTTGTTACGACTT-3').

[0065] The 16S rDNA sequence of the bacterial strain is as follows:

[0066] >

[0067] CCGGAGTGCCTATACATGCAGTCGAACGAGACCTTCGGGTCTAGTGGCGCACGGGT

[0068] GCGTAACGCGTGGGAATCTGCCCTTGGGTTCGGAATAACAGTTGGAAACGACTGCTAAT

[0069] ACCGGATGATGACGAAAGTCCAAAGATTTATCGCCCAGGGATGAGCCCGCGTAGGATTA

[0070] GCTAGTTGGTGAGGTAAAGGCTCACCAAGGCGACGATCCTTAGCTGGTCTGAGAGGATG

[0071] ATCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTAGGGA

[0072] ATATTGGACAATGGGGGCAACCCTGATCCAGCAATGCCGCGTGAGTGATGAAGGCCTTA

[0073] GGGTTGTAAAGCTCTTTTACCCGGGATGATAATGACAGTACCGGGAGAATAAGCCCCGG

[0074] CTAACTCCGTGCCAGCAGCCGCGGTAATACGGAGGGGGCTAGCGTTGTTCGGAATTACT

[0075] GGGCGTAAAGCGCACGTAGGCGGCGATTTAAGTCAGAGGTGAAAGCCCGGGGCTCAAC

[0076] CCCGGAACTGCCTTTGAGACTGGATTGCTTGAACATCGGAGAGGTGAGTGGAATTCCGA

[0077] GTGTAGAGGTGAAATTCGTAGATATTCGGAAGAACACCAGTGGCGAAGGCGGCTCACTG

[0078] GACGATTGTTGACGCTGAGGTGCGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTG

[0079] GTAGTCCACGCCGTAAACGATGATAACTAGCTGCTGGGGTGCATGGCATTTCAGTGGCG

[0080] CAGCTAACGCATTAAGTTATCCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGG

[0081] AATTGACGGGGGCCTGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCGCA

[0082] GAACCTTACCAACGTTTGACATCCCTATCGCGGATCGTGGAGACACTTTCCTTCAGTTCG

[0083] GCTGGATAGGTGACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGT

[0084] TAAGTCCCGCAACGAGCGCAACCCTCGCCTTTAGTTGCCATCATTTAGTTGGGTACTCTA

[0085] AAGGAACCGCCGGTGATAAGCCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCC

[0086] CTTACGCGTTGGGCTACACACGTGCTACAATGGCGACTACAGTGGGCAGCCACTCCGCG

[0087] AGGAGGAGCTAATCTCCAAAAGTCGTCTCAGTTCGGATCGTTCTCTGCAACTCGAGAGC

[0088] GTGAAGGCGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCCAGG

[0089] CCTTGTACACACCGCCCGTCACACCATGGGAGTTGGATTCACTCGAAGGCGTTGAGCTAACCGCAAGGAGGCAGGCGACCAGCAG.

[0090] This new strain of bacteria is classified and named Sphingomonas sp. and numbered NY-1.

[0091] Packaging of saline-alkali soil: After mixing the saline-alkali soil, pack it into small flower pots with length: width: height = 7.3cm:10cm:12.5cm, 500g±10g per pot.

[0092] Preparation of bacterial solution:

[0093] Use a bacterial loop to pick the selected Sphingomonas sp. on the Luria-Bertani (LB) solid medium and put it into a conical flask containing 200 mL of LB liquid medium. After constant temperature shaking at 180 rpm and 30°C for 24 hours, the bacterial solution was obtained. The bacterial solution was centrifuged at 8000 rpm and 4°C. The bacteria were diluted with sterile distilled water to OD 600 =1, the number of viable bacteria in the bacterial solution is 2×10 9 CFU / mL.

[0094] NY-1 treatment group (6 replicates):

[0095] The above-mentioned Sphingomonas bacterial solution was applied to the potting soil once every seven days, 50 mL per pot each time.

[0096] Control treatment group (6 replicates):

[0097] Sterile distilled water was applied to the potting soil every seven days, 50 mL per pot each time.

[0098] The soil performance monitoring results were obtained after 5 uses, as shown in Table 1.

[0099] Table 1

[0100]

[0101]

[0102] According to the test data analysis in Table 1, the Sphingomonas sp. strain screened by the present invention can significantly reduce soil conductivity, exchangeable sodium content, alkalinity and total salt content, and significantly increase soil organic matter, available phosphorus content and acid phosphatase activity, achieving unexpected results.

[0103] Example 2

[0104] In some embodiments, a composite bacterial fertilizer for effectively improving saline-alkali soil is provided, including Bacillus subtilis, Exiguobacterium acetylicum, Bacillus velez, Pseudomonas fluorescens, Rhodococcus capsulatus, and the above-mentioned bacteria species for effectively improving saline-alkali soil, Sphingomonas sp. The study found that the composite bacterial solution has a more prominent effect on the restoration of saline-alkali land than a single bacterial solution; in some embodiments, the six composite bacterial solutions have a significantly improved effect on the restoration of saline-alkali land than 5, 4, 3, 2, and 1 composite bacterial agents, achieving unexpected technical effects.

[0105] In some embodiments, the volume ratio of Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velez, Pseudomonas fluorescens, Rhodococcus capsulatus and the species Sphingomonas sp. is 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2. Preferably, the volume ratio of Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velez, Pseudomonas fluorescens, Rhodococcus capsulatus and the species Sphingomonas sp. is 1:1:1:1:1:1:1.

[0106] In some embodiments, the number of each bacterium is not less than 2.0×10 9 CFU / mL.

[0107] The specific embodiments are as follows:

[0108] Use this compound bacterial solution regularly in flower pots.

[0109] (1) Packaging of saline-alkali soil: After mixing the saline-alkali soil, pack it into small flower pots with a length: width: height = 7.3 cm: 10 cm: 12.5 cm, 500 g ± 10 g per pot.

[0110] (2) Preparation of bacterial solution: Use a bacterial loop to pick Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas on LB solid medium and place them into a conical flask containing 200 mL LB liquid medium. After constant temperature shaking at 180 rpm and 30°C for 24 h, the bacterial solution was obtained. The bacterial solution was centrifuged at 8000 rpm and 4°C. The bacteria were diluted with sterile distilled water to an OD of 600 =1, then Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas were mixed in a volume ratio of 1:1:1:1:1:1, and the number of viable bacteria in each bacterial solution was 2×10 9 CFU / mL, and the control group was not inoculated with microorganisms.

[0111] (3) Apply microbial culture solution once every seven days, 50 mL per pot each time, and add an equal amount of sterile distilled water to the control group.

[0112] Test data as attached Figure 2-16 As shown, specifically, in the figure, CK is the control group; T1 is Bacillus subtilis liquid, T2 is Bacillus velez liquid, T3 is Exiguobacterium acetylicum liquid, T4 is Pseudomonas fluorescens liquid, T5 is Rhodococcus capsulatum liquid, T6 is Sphingomonas sp. liquid, and SynComes is a composite liquid.

[0113] After 40 days of bacterial solution improvement, compared with a single strain, the composite bacterial solution significantly reduced soil pH and cation exchange capacity. T3, T6 and composite bacterial solution significantly reduced soil exchangeable sodium content. Based on exchangeable sodium and cation exchange capacity, the alkalinity was obtained. It was found that Bacillus subtilis, Exiguobacterium acetylicum, Bacillus velez, Sphingomonas and composite bacterial solution could significantly reduce soil alkalinity. In addition, both single strains and composite bacterial solution could significantly reduce soil total salt content, which shows that halophilic bacteria have the ability to repair saline-alkali land, and composite bacterial solution has the best effect.

[0114] The nutrient indexes of the soil showed that T1, T6 and the composite bacterial solution could significantly increase the soil organic matter content, T5 and the composite bacterial solution could significantly increase the soil reduced nitrogen content and acid phosphatase activity, T6 significantly increased the available phosphorus content in the soil, both single bacterial species and composite bacterial solution significantly increased the soil available potassium content, but only the composite bacterial solution significantly increased the soil urease activity. The above data all indicate that the composite bacterial solution has a better remediation effect on saline-alkali land than a single bacterial solution, and can be used as a bacterial fertilizer for saline-alkali land improvement.

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A strain of bacteria that effectively improves saline-alkali soil, characterized in that: The strain is classified and named as Sphingomonas sp. and is deposited in the China General Microbiological Culture Collection Center with a deposit number of CGMCC NO.32220.

2. A bacterial agent, characterized in that The invention comprises the bacterial strain for improving saline-alkali soil as claimed in claim 1.

3. The bacterial agent according to claim 2, characterized in that The bacterial agent is at least one of a solid bacterial agent, a liquid bacterial agent and a gel bacterial agent.

4. Use of the bacterial strain for improving saline-alkali soil as claimed in claim 1 in the preparation of saline-alkali land improved products.

5. The use according to claim 4, characterized in that The product is at least one of biological microbial agents, biological pesticides and biological fertilizers.

6. A composite bacterial fertilizer for effectively improving saline-alkali soil, characterized in that: The bacteria include Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velez, Pseudomonas fluorescens, Rhodococcus capsulatus and the bacteria species Sphingomonas sp. for effectively improving saline-alkali soil as claimed in claim 1.

7. The composite bacterial fertilizer for effectively improving saline-alkali soil according to claim 6, characterized in that: The volume ratio of Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas sp. is 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2: 0.8-1.2; Preferably, the volume ratio of Bacillus thaliana, Exiguobacterium acetylicum, Bacillus velez, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas sp. is 1:1:1:1:1:1:

1.

8. The composite bacterial fertilizer for effectively improving saline-alkali soil according to claim 7, characterized in that: In the compound bacterial fertilizer, the number of each bacteria is not less than 2.0×10 9 CFU / mL.

9. A method for preparing a composite bacterial fertilizer for effectively improving saline-alkali soil as claimed in any one of claims 6 to 8, characterized in that: The following methods are included: Step 1, placing Bacillus subtilis, Exiguobacterium acetylicum, Bacillus Velezii, Pseudomonas fluorescens, Rhodococcus capsulatus and Sphingomonas sp. in culture medium respectively, shaking at constant temperature, to obtain six bacterial liquids; Step 2, centrifuging the six bacterial solutions obtained in step 1 respectively to obtain six bacterial cells; Step 3: dilute the six bacterial cells obtained in step 2 with sterile distilled water, then mix the six diluted bacterial solutions, and adjust the volume with sterile distilled water to obtain a composite bacterial fertilizer.

10. Use of the composite bacterial fertilizer for effectively improving saline-alkali soil as claimed in any one of claims 6 to 8 in improving saline-alkali land.

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