Microbial complex microbial inoculant and application thereof in soil improvement

Abstract

The invention discloses a compound microbial inoculant and application thereof in soil improvement, belongs to the technical field of microorganisms, and aims to solve the problem of soil improvement of vaccinium vitis vinifera which has relatively high requirements on soil growth conditions. The method provided by the invention comprises the following steps: compounding Enterobacter ludwigii and Oidiodendron maius according to a volume ratio of 2: 1 to form a microbial composite inoculant, then inoculating the microbial composite inoculant to the bilberry rhizosphere soil, and culturing for 30 days to determine the bilberry rhizosphere soil improvement effect. Researches find that by applying the complex microbial inoculant, the content of organic carbon and rapidly available phosphorus in the bilberry rhizosphere soil can be increased, the pH value of the soil can be reduced, and the activities of urease, sucrase and catalase in the bilberry rhizosphere soil can be improved. The technical scheme of the invention provides a microbial complex microbial inoculant for later large-scale production of cowberry, and has important application value and market prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microbial technology, in particular to a soil improvement microbial compound inoculant and application thereof. BACKGROUND

[0002] Microorganisms are the invisible providers of soil fertility. Microbial soil improvement technology is considered as one of the core technologies in the field of forestry and environmental remediation due to its green, efficient and sustainable characteristics. However, the effect of single strain on complex soil problems is very limited, especially for the rhizosphere soil improvement of specific plants, such as blueberry, which lacks root hairs and is more demanding on growth conditions, and requires more precise microbial combination to improve the soil environment. Blueberry grows in cold and acidic soil in the northern hemisphere, and has very high requirements for soil pH and nutrients. Although there are reports on the functions of Enterobacter and mycorrhizal fungi in the prior art, a technical solution for applying Enterobacter ludwigii and Oidiodendron maius in a specific ratio to blueberry rhizosphere soil improvement has not been disclosed. In this context, it is necessary to provide a method for improving soil with a specific combination of Enterobacter ludwigii and Oidiodendron maius microbial inoculant. SUMMARY

[0003] The present application provides a microbial compound inoculant, which is a specific combination of Enterobacter ludwigii and Oidiodendron maius compounded in a volume ratio of 2:1. The effective viable count of Enterobacter ludwigii in the compounded inoculant is 6.7x10 6 CFU / mL, and the spore concentration of Oidiodendron maius is 3.3x10 6 CFU / mL. 6mL of the compounded inoculant is applied to 80g of blueberry rhizosphere soil, and the application is performed once every 15 days, and the treatment is continued for 30 days. Compared with the control group, the microbial compound inoculant can effectively improve the nutrient conditions of blueberry rhizosphere soil after 30 days of application, including reducing the pH value of blueberry rhizosphere soil to create an acidic soil environment, increasing the content of organic carbon and available phosphorus, and improving the activity of key enzymes (urease, sucrose, and hydrogen peroxide) in soil. The application of the microbial compound inoculant in blueberry rhizosphere soil improvement can promote the accumulation and transformation of organic matter in blueberry rhizosphere soil, and effectively solve the growth limitation of blueberry in oligotrophic acidic soil.

[0004] The present application provides a soil improvement microbial compound inoculant, wherein the selection and combination of strains are not simply selected and combined, but are obtained through a large number of experiments of screening, combination and verification, and have a significant effect on soil improvement.

[0005] The technical effect of the present application: the Enterobacter ludwigii and the Oidiodendron maius are compounded into a microbial compound microbial agent at a specific volume ratio of 2:1, and after inoculation into the rhizosphere soil of the blueberry, it is found that it has obvious soil improvement effect. The microbial compound microbial agent in the present application reduces the pH value of the rhizosphere soil of the blueberry, creates a more suitable acidic environment for the growth of the blueberry, at the same time, the organic carbon content of the soil is increased by 10.71%, the available phosphorus content is increased by 142.26%, effectively breaking the growth restriction of the blueberry in the oligotrophic acidic soil, and at the same time, the activity of the key enzymes (urease, sucrose, hydrogen peroxide) of the soil is improved, especially the activity of the hydrogen peroxide is improved by 148.62%, which indicates that the health and resistance of the soil ecosystem are greatly enhanced. In the present application, the microbial compound microbial agent is compounded at a specific ratio, so that the microbial compound microbial agent and the rhizosphere environment of the blueberry form a soil-microorganism synergistic system, improve the physical and chemical properties of the rhizosphere soil of the blueberry, strengthen the material cycle of the soil, and provide sustainable and stable fertility support for the healthy growth of the blueberry, and provide reliable technical support for realizing the efficient and green large-scale production of the blueberry in the facility forestry.

[0006] The microbial compound microbial agent in the present application is Enterobacter ludwigii, the preservation number of which is CCTCC PB 2021045, and it is purchased from the China Center for Type Culture Collection; the preservation number of the Oidiodendron maius is ATCC 60377 (purchased from Beijing Bio-Bio-Wei Biological Technology Company, https: / / www.biobw.org / category / index?keywords=Oidiodendron+maius&id=0). BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 : the influence diagram of inoculating the microbial compound microbial agent on the pH of the rhizosphere soil of the blueberry;

[0008] Figure 2 : the influence diagram of inoculating the microbial compound microbial agent on the organic carbon in the rhizosphere soil of the blueberry;

[0009] Figure 3 : the influence diagram of inoculating the microbial compound microbial agent on the available phosphorus in the rhizosphere soil of the blueberry;

[0010] Figure 4 : the influence diagram of inoculating the microbial compound microbial agent on the urease activity in the rhizosphere soil of the blueberry;

[0011] Figure 5 : the influence diagram of inoculating the microbial compound microbial agent on the sucrose activity in the rhizosphere soil of the blueberry;

[0012] Figure 6Figure of effect of inoculating microbial compound microbial agent on soil catalase activity. DETAILED DESCRIPTION

[0013] The application will be described in detail below by examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the protection scope of the application. The skilled in the art can make some non-essential improvements and adjustments to the application according to the above content of the application.

[0014] Example 1

[0015] The plant material used for soil potting is Vaccinium vitis-idaea L. of Ericaceae Vaccinium.

[0016] The test soil used in the application is prepared as follows: the soil is sieved (2 mm) to remove impurities, sterilized at 121℃ for 2 h, and after standing and cooling, a transparent plastic tissue culture bottle is used, and 80 g of sieved soil is filled in each bottle.

[0017] The components of the soybean casein agar medium TSA medium used in the application are: 15 g of tryptone, 5 g of soybean peptone, 5 g of sodium chloride, and 1000 mL of distilled water. The components of the potato dextrose agar medium PDA medium are: 200 g of potato, 20 g of glucose, 3 g of potassium dihydrogen phosphate, 1.5 g of magnesium sulfate, and 1000 mL of distilled water.

[0018] The microbial compound microbial agent is prepared as follows:

[0019] I. Enterobacter ludwigii is inoculated into TSA medium, and cultured in a shaking bed at 28℃ and 180 rpm until OD 600 =1, at which time the viable bacterial concentration is about 1×10 7 CFU / mL, to obtain a strain fermentation liquor;

[0020] II. Lecythophora hoffmannii is inoculated into PDA medium, and cultured in a shaking bed at 30℃ and 150 rpm for 7 days, at which time the spore concentration is about 1×10 7 CFU / mL, to obtain a strain fermentation liquor;

[0021] III. The liquid fermentation liquors obtained in steps I and II are mixed in a volume ratio of 2:1 to prepare a microbial compound microbial agent, wherein the effective viable bacterial count of Enterobacter ludwigii in the microbial compound microbial agent is 6.7×10 6 CFU / mL, and the spore concentration of Lecythophora hoffmannii is 3.3×10 6 CFU / mL.

[0022] Example 2:

[0023] The application inoculates the rhizosphere soil with the microbial compound inoculant, and then tests the soil improvement effect. Two treatment combinations are set in the experiment, including a blank control group (CK) without inoculating the microbial compound inoculant in the soil and an inoculant experiment group inoculating the microbial compound inoculant in the soil, which are marked as the control group and the experiment group in the figure. The inoculant experiment group is applied with 6 mL of the inoculant every 15 days, and the control group is added with the same amount of distilled water every 15 days. After the inoculant experiment lasts for 30 days, the soil samples are collected to measure the physical and chemical indexes (pH, available phosphorus, organic matter) and enzyme activities (urease, sucrose, catalase) of the soil.

[0024] (I) Soil physical and chemical property determination

[0025] Soil is the basic source of nitrogen (N), phosphorus (P), potassium (K) and other trace elements required by plants. The content and conversion efficiency of soil organic matter and minerals directly determine the nutritional status of plants. The soil physical and chemical property determination strictly refers to Soil Agricultural Chemistry Analysis. The rhizosphere soil of the blueberry cultivated for 30 days in the example is collected, and the soil is placed in an envelope and naturally dried for use.

[0026] The pH value is measured by the potential method; the organic carbon content is analyzed by the potassium dichromate oxidation method; and the available phosphorus content is quantitatively analyzed by the sodium bicarbonate extraction combined with the molybdenum-antimony anti-colorimetric method. The effects of the inoculant on the soil pH value, organic carbon content and available phosphorus content are shown in Figure 1 , Figure 2 , Figure 3 . The test results show that the pH value of the rhizosphere soil of the blueberry treated by the microbial compound inoculant shows a downward trend, which is particularly beneficial to the growth of the blueberry in the acidic soil environment; the organic carbon content is increased by 10.71% compared with that of the control group; and the available phosphorus content is increased by 142.26% compared with that of the control group. This change shows that the microbial compound inoculant promotes the accumulation and conversion of soil organic matter and effectively activates the insoluble phosphorus in the soil.

[0027] Blueberry is an acidophilic and oligotrophic plant, which is sensitive to the rhizosphere soil environment. The microbial inoculant for ordinary crops is often difficult to effectively colonize and play a role in the unique rhizosphere environment of the blueberry. Enterobacter bacteria are generally considered to be active in the neutral or slightly alkaline environment, and the application successfully makes them colonize and play a role in the acidic rhizosphere soil of the blueberry by compounding them with the acidophilic Olpitrichum sp. according to a certain proportion.

[0028] (II) Soil enzyme activity determination

[0029] (1) Effect of inoculant on soil urease activity

[0030] Soil urease is a hydrolytic enzyme secreted by soil microorganisms and plant roots, and its main function is to catalyze the hydrolysis of urea. Its activity is significantly positively correlated with the number and diversity of microorganisms and the content of soil organic matter. Therefore, it is a sensitive indicator for measuring the "vitality" and fertility level of soil. In this embodiment, the soil urease activity is determined by the indigo phenol blue colorimetric method. The test results of the effect of inoculating the microbial inoculant on the soil urease activity are shown in Table 1. Figure 4 As shown in Table 1, the urease activity in the rhizosphere soil of the blueberry treated by the inoculating microbial inoculant was increased by 58.86% compared with the control group.

[0031] (2) Effect of inoculating microbial inoculant on soil invertase activity

[0032] The core biochemical function of soil invertase is to catalyze the hydrolysis of sucrose to generate glucose and fructose that can be directly utilized by plants and microorganisms. The invertase activity directly reflects the ability of soil to convert complex organic matter into effective energy. In this embodiment, the soil invertase activity is determined by the 3,5-dinitrosalicylic acid (DNS) method. The test results of the effect of inoculating the microbial inoculant on the soil invertase activity are shown in Table 2. Figure 5 As shown in Table 2, the invertase activity in the rhizosphere soil of the blueberry treated by the inoculating microbial inoculant was increased by 14.54% compared with the control group.

[0033] (3) Effect of inoculating microbial inoculant on soil catalase activity

[0034] Catalase protects soil organisms and plant roots from oxidative damage by removing H2O2 and decomposing it into harmless water and oxygen. This enzyme helps maintain the redox balance of the soil environment and ensures normal microbial life activities. In this embodiment, the soil catalase activity is determined by the potassium permanganate titration method. The test results of the effect of inoculating the microbial inoculant on the soil catalase activity are shown in Table 3. Figure 6 As shown in Table 3, the catalase activity in the rhizosphere soil of the blueberry treated by the inoculating microbial inoculant was increased by 148.62% compared with the control group.

[0035] In terms of soil enzyme activity, the urease activity was increased by 58.86% compared with the control group, indicating that the microbial inoculant significantly enhanced the nitrogen transformation capacity of the soil and promoted the decomposition and transformation of urea. The invertase activity was increased by 14.54% compared with the control group, reflecting the enhancement of the soil carbon cycle capacity. The catalase activity was increased by 148.62% compared with the control group, which indicates that the inoculation treatment greatly enhances the antioxidant capacity of the soil, effectively removes excess active oxygen, and protects the roots and soil microorganisms from oxidative damage. In summary, the microbial inoculant optimizes the rhizosphere soil microecological environment by improving the soil physical and chemical properties and enhancing the enzyme activity.

[0036] The embodiment results show that the microbial composite microbial inoculant prepared by mixing Enterobacter ludwigii and Cryptomyces maximus in a volume ratio of 2:1 not only simultaneously increases the contents of soil organic carbon and available phosphorus, but also significantly reduces the pH value and synergistically activates the activities of urease, invertase and catalase. The increase of the acid environment and the enzyme activity is crucial for the growth of the specific plant Vaccinium vitis-idaea, and creates a rhizosphere microenvironment suitable for the growth of Vaccinium vitis-idaea. The technical effect of the present application is a systematic and comprehensive improvement, which provides an efficient, green and specific microbial solution for Vaccinium vitis-idaea, especially for large-scale planting in facility forestry, and has important application value and broad market prospect.

Claims

1. A microbial complex inoculant, characterized in that, The microbial complexing agent is composed of Enterobacter ludwigii Enterobacter ludwigii and Oidiodendron macrosporum Oidiodendron maius .

2. The microbial complexing agent according to claim 1, characterized in that, The Ludwig's intestinal bacillus and the large-spore tree powder spore are compounded into a composite microbial agent according to a volume ratio of 2:

1. 3.The microbial composite microbial agent according to claim 2, characterized in that, The effective viable cell number of Enterobacter ludwigii in the prepared composite microbial agent was 6.7 x 10 6 CFU / mL, and the spore concentration of Pistia spores was 3.3 x 10 6 CFU / mL.

4. Application of the microbial composite agent in soil improvement according to any one of claims 1 to 3.

5. The use of the microbial complexing agent according to claim 4 for soil improvement, characterized in that, After 30 days of application of the microbial composite agent, the pH of the blueberry rhizosphere soil is reduced, the available phosphorus content, organic matter content, urease activity, invertase activity and catalase activity are increased.

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