Microbial agent for improving soil quality of subtropical secondary forest

Abstract

The present application relates to a kind of microbial inoculant, specifically to a kind of microbial inoculant for improving subtropical secondary forest soil quality, belong to the field of biotechnology.The microbial inoculant includes A component, B component and C component;The A component includes Bacillus subtilis, Bacillus amyloliquefaciens and Bacillus mucilaginosus;The B component includes Shewanella putrefaciens, Podospora sp. And Burkholderia sp.;The C component includes superphosphate, adhesive, soil bulking agent and water.The microbial inoculant is generated by the microbial growth-metabolism-death process of microbial residue carbon and nutrient, green, efficiently improve subtropical secondary forest soil organic matter content, phosphorus-solubilizing nitrogen-fixing, improve soil microbial community structure, promote secondary forest positive succession.

Description

Technical Field

[0001] This invention relates to a microbial inoculant, specifically a microbial inoculant for improving the soil quality of subtropical secondary forests, and belongs to the field of biotechnology. Background Technology

[0002] Secondary forests account for approximately 57% of China's total forest area, making them the main body of China's forest resources. The restoration and management of secondary forests are of great significance to national ecological security. Preliminary surveys indicate that subtropical secondary forests generally face problems such as nutrient imbalance (especially phosphorus limitation), organic matter deficiency, and low soil enzyme activity. This has led to varying degrees of "climax soil conditions," resulting in slow or even halted succession, difficult restoration, and low-quality subtropical secondary forests.

[0003] Currently, there are few technologies specifically designed for improving forest soil quality. Most research focuses on farmland soils, and these soil-improving agents or reagents typically require pressurized reaction vessels or similar processes, which are cumbersome and costly. Furthermore, due to significant differences between farmland and forest ecosystems in terms of biodiversity, material cycling, and energy flow, the microbial community structure and function in the two types of soils differ. Therefore, using the same soil-improving agent may not effectively promote microbial activity in the target soil, thus failing to achieve the desired improvement effect.

[0004] Therefore, developing technologies to improve forest soil quality and break the apex soil structure of subtropical secondary forests is a major need for forestry ecological construction and sustainable development in subtropical regions. Currently, there are no effective microbial agents that can improve forest land with different soil types. Summary of the Invention

[0005] To overcome the gaps in existing forest soil improvement technologies, and to address the problems of cumbersome operation, high cost, and difficulty in applying other soil amendments to forest soil improvement, this invention proposes a microbial agent to improve the quality of subtropical secondary forest soil. Utilizing the microbial residual carbon and nutrients produced during the microbial growth-metabolism-death process, this agent can greenly and efficiently increase the organic matter content of subtropical secondary forest soil, solubilize phosphorus and fix nitrogen, improve the soil microbial community structure, and promote positive succession of secondary forests.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a microbial inoculant for improving the soil quality of subtropical secondary forests, comprising component A, component B, and component C; wherein component A comprises Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus; wherein component B comprises Shewanella putrefaciens, Podospora sp., and Burkholderia sp.; and wherein component C comprises superphosphate, binder, soil loosening agent, and water.

[0008] Preferably, in component A, the weight ratio of Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus is 3:3:2.

[0009] Preferably, in component B, the weight ratio of Shewanella putrefaciens, Podospora sp., and Burkholderia sp. is 3:2:1.

[0010] Preferably, component B further includes a catalyst, which is lactic acid bacteria, yeast, and nitrifying bacteria.

[0011] Preferably, in component C, the weight ratio of superphosphate, binder, soil loosening agent and water is 3:2:1:3.

[0012] Preferably, the weight ratio of components A, B, and C is 1:1:1.

[0013] Preferably, the microbial agent also includes biochar.

[0014] The microbial agent provided by this invention has the following beneficial effects:

[0015] It can significantly increase the organic matter content of subtropical secondary forest soil, improve the activity of soil urease and phosphatase, and significantly affect the relative abundance of protective and functional bacteria in the soil, increase the available phosphorus content in the soil, and relieve phosphorus limitation.

[0016] The preparation method of this microbial agent is simple and easy to operate, low in cost, and produces no secondary pollution, thus possessing broad market value. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] The raw materials used in the examples are sourced from:

[0019] Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus were obtained from Shandong Yihao Biotechnology Co., Ltd.; Shewanella putrefactive was obtained from Wuhan Gray Algae Biotechnology Co., Ltd.; Stylomata stipecifolium was obtained from Shanghai Bohu Biotechnology Co., Ltd.; Burkholderia was obtained from Shanghai Boke Biotechnology Co., Ltd.; Lactic acid bacteria were obtained from Henan Ruigao Biotechnology Co., Ltd.; yeast was obtained from Jinan Qiyue Chemical Technology Co., Ltd.; nitrifying bacteria were obtained from Guangzhou Ranyi Bio-Environmental Technology Co., Ltd.; superphosphate was obtained from Shandong Weifeng Chemical Co., Ltd.; binder (i.e., bentonite) was obtained from Sishui Changxing Metallurgical Casting Materials Co., Ltd.; soil loosening agent (i.e., soil loosening agent) was obtained from Renqiu Kewei Chemical Co., Ltd.; chemically pure hydrochloric acid and chemically pure sodium bicarbonate were obtained from Xilong Science.

[0020] The main components of the microbial agent are: Component A (protective bacteria), Component B (functional bacteria), Component C (auxiliary components), and biochar; Component A includes Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus; Component B includes Shewanella putrefaciens, Podospora sp., Burkholderia sp., as well as lactic acid bacteria, yeast, and nitrifying bacteria; Component C includes superphosphate, binder, soil loosening agent, and water.

[0021] Preparation of inoculant:

[0022] Component A was prepared at room temperature by mixing Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus in a weight ratio of 3:3:2.

[0023] Component B is prepared at room temperature by mixing Shewanella putrefaciens, Podospora sp., and Burkholderia sp. in a weight ratio of 3:2:1, and then adding 3g each of lactic acid bacteria, yeast, and nitrifying bacteria. In practical applications, lactic acid bacteria, yeast, and nitrifying bacteria are only used as auxiliary activation catalysts, so there are no special requirements for their dosage, and the amount added can be 3-5g.

[0024] Component C is prepared by mixing superphosphate, binder, soil loosening agent and water in a weight ratio of 3:2:1:3 at room temperature, and adjusting the pH to neutral with chemically pure dilute hydrochloric acid or sodium bicarbonate; among them, superphosphate is used as a stabilizer.

[0025] The prepared components A, B, and C are thoroughly mixed at room temperature in a weight ratio of 1:1:1 to obtain a mixture. Biochar is then added as a base to prepare a microbial agent. The amount of mixture and biochar used is sufficient to ensure complete distribution within the mixture; in this invention, the weight ratio of mixture to biochar is selected as 1:20.

[0026] Experiments were conducted on various forest types, including evergreen broad-leaved forests, mixed pine and broad-leaved forests, and pine forests, in three locations: Jiande City in Hangzhou, Jinyun County in Lishui, and Yueqing City in Wenzhou. The specific locations and soil types are shown in Table 1.

[0027] Table 1 Soil Types

[0028]

[0029]

[0030] The application rate of the microbial agent was determined based on the actual organic matter content of the forest soil (Table 2). No additional management was required after application. In Examples 1-6 and 8-9, the microbial agent was applied at a rate of 200g per square meter, while in Example 7, it was applied at a rate of 100g per square meter.

[0031] Table 2 Standards for Application Rate of Microbial Agents

[0032]

[0033] The effect of the fungicide was determined 30 days after application. During the test, soil samples were randomly drilled from the top 0-20cm of the forest using the cross-five-point method. After removing debris, the samples were brought back to the laboratory.

[0034] A portion of the soil samples were dried to constant weight at 70℃ for the determination of soil organic matter and available phosphorus content. Soil organic matter was determined by combustion using an elemental analyzer (Multi N / C 3000, Analytic Jena AG, Germany), and available phosphorus content was determined by a continuous flow analyzer (AA3, SEAL, Germany). The remaining soil samples were refrigerated at 4℃ and hydrolyzed with 6 mol / L HCl at 105℃. Amino sugars were then separated using GC / MS (8890-7000E, Agilent, USA) to calculate the carbon content of the microbial residue. The results are shown in Table 3. The controls in Tables 3-6 refer to the contents of samples where no inoculant was applied, corresponding to the locations in the examples.

[0035] Table 3. Effects of microbial inoculant application on soil nutrients.

[0036]

[0037]

[0038] Soil urease and phosphatase activities were extracted and measured using a kit (Suzhou Keming Biotechnology Co., Ltd.). The results are shown in Table 4.

[0039] Table 4. Effects of microbial inoculant application on soil enzyme activity

[0040]

[0041]

[0042] The relative abundances of *Bacillus subtilis*, *Bacillus amyloliquefaciens*, *Bacillus mucilaginosus*, *Shewanella putrefactive*, *Stenocystis*, and *Burkholderia* in soil were determined using high-throughput sequencing. The results are shown in Tables 5 and 6.

[0043] Table 5. Effects of inoculant application on the relative abundance of soil conservation bacteria.

[0044]

[0045]

[0046] Table 6. Effects of microbial inoculant application on the relative abundance of soil functional bacteria.

[0047]

[0048] As can be seen from Tables 3-6, the application of the microbial agent provided by the present invention can significantly increase the soil organic matter content in subtropical secondary forests, increase the activity of soil urease and phosphatase, and significantly affect the relative abundance of protective and functional bacteria in the soil, increase the available phosphorus content in the soil, and relieve phosphorus limitation.

[0049] Regarding soil organic matter content, the increase was particularly significant in yellow soil from shrub forests, increasing by 22.11%. In terms of microbial residual carbon, the increase was most significant in red soil from pine forests, increasing by 33.31%. Regarding available phosphorus content, all soil types showed significant increases, with bamboo forest soil showing the most significant increase, reaching nearly 60%, with an average increase of 37.67%, effectively relieving the limitation of phosphorus on soil nutrients (Table 3). Simultaneously, the application of the microbial agent also significantly affected soil enzyme activity, with urease activity increasing by up to 20.93% and phosphatase activity increasing by up to 29.75% (Table 4). Furthermore, the application of the microbial agent significantly increased the relative abundance of protective bacteria such as Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus, as well as functional bacteria such as Shewanella putrefactive bacteria, Stylomata spp., and Burkholderia spp. This indicates that the microbial agent provided by this invention effectively relieves the limitation of phosphorus on soil nutrients while promoting the growth and metabolism of beneficial soil bacteria.

Claims

1. A microbial inoculant for improving soil quality in subtropical secondary forests, characterized by, It includes components A, B, and C; component A includes Bacillus subtilis (… Bacillus subtilis ), Bacillus amyloliquefaciens ( Bacillus amyloliquefaciens ) and Bacillus mucilaginosus ( Bacillus mucilaginosus ); Component B includes Shewanella putrefactive bacteria ( ); Shewanella putrefaciens ), Podospora sp. and Burkholderia sp.; Component C includes superphosphate, binder, soil conditioner and water; The weight ratio of Bacillus subtilis (Bacillus subtilis) Bacillus subtilis ), Bacillus amyloliquefaciens (Bacillus amyloliquefaciens) Bacillus amyloliquefaciens ) and Bacillus mucilaginosus (Bacillus mucilaginosus) Bacillus mucilaginosus is 3:3:

2. In component B, *Shevania putrefactive* (… Shewanella putrefaciens The weight ratio of Podospora sp. and Burkholderia sp. was 3:2:1; The weight ratio of the A, B and C components is 1:1:

1.

2. The microbial inoculant of claim 1, wherein, The B component further comprises lactic acid bacteria, yeast and nitrifying bacteria.

3. The microbial inoculant of claim 1, wherein, In the C component, the weight ratio of superphosphate, adhesive, soil aerator and water is 3:2:1:

3.

4. The microbial inoculant of claim 1, wherein, The pH of the C component is neutral.

5. The microbial inoculant of claim 1, wherein, The microbial agent further comprises biochar.

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