Microbial soil conditioner for promoting growth of fruit trees

Abstract

The invention belongs to the technical field of microorganisms, and discloses a microbial soil conditioner containing a Streptomyces kunmingensis 5A2 strain, the strain is preserved in Guangdong Province Microbial Culture Collection Center, and the preservation number is GDMCC No.65130. The invention also discloses a preparation method of the microbial soil conditioner containing the Streptomyces kunmingensis 5A2 strain, and the strain is preserved in Guangdong Province Microbial Culture Collection Center. By applying the microbial soil conditioner in the growth stage of fruit trees, the physicochemical properties of orchard soil are improved, and the growth of the fruit trees is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms and discloses a microbial soil conditioner for improving soil microecological structure and promoting the growth of fruit trees and a preparation method thereof. Background Art

[0002] The rhizosphere microenvironment of fruit tree growth is a hot spot where the soil, root system and soil microorganisms of fruit trees are closely integrated and interact with each other. It is the main place for fruit trees to absorb nutrients and grow and develop. A good rhizosphere microenvironment of fruit trees can promote the healthy growth of fruit trees and improve the quality of tea. Fruit tree soil microorganisms mainly include bacteria, archaea, fungi and actinomycetes. The composition of microorganisms varies with the growth altitude of fruit trees, soil type and nutrient status, fruit tree variety, tree age and growing season. Studies have shown that microorganisms in the rhizosphere microenvironment play an important role in the cultivation and quality formation of fruit trees. Including: (1) decomposing organic matter, releasing nutrients required by plants, such as nitrogen, phosphorus, potassium, etc., increasing soil fertility and maintaining soil permeability, improving soil quality, promoting the growth of fruit trees and increasing yields. (2) Microorganisms inhibit the growth and reproduction of pathogens and pests through mechanisms such as competing for resources and secreting antibiotics, playing a role in reducing the occurrence of diseases and pests. (3) Microorganisms can synthesize compounds related to the aroma and flavor of tea, such as tea polyphenols and aromatic substances. The structure and activity level of microbial communities make the quality of tea differ.

[0003] Screening, functional definition and applicable environment research of native beneficial bacteria in the soil have always been the research focus of agricultural production. At present, a large number of soil beneficial microbial preparations or fertilizers have appeared on the market. Common types of probiotics used for soil conditioning include Bacillus subtilis, Bacillus megaterium, Bacillus thuringiensis, Bacillus licheniformis, Bacillus laterosporus, Bacillus gelatinous, Streptomyces jingyangensis, brown nitrogen-fixing bacteria and lactic acid bacteria, etc. Since microorganisms have a certain selectivity for the ecological environment, the stability and reliability of microbial agents are easily affected by changes in the soil microenvironment. Actinomycetes are an important microbial group in the soil, but they are currently widely used in agricultural production, and the number of actinomycetes with clear functions is scarce. The development and utilization of actinomycete resources in the soil is of great value.

[0004] With the development of economy and society, the planting area and annual output of fruit trees in Hunan, Jiangxi, Guangdong and Guangxi have increased rapidly. However, in areas of South China affected by high temperature and rainy environmental conditions, soil nutrients such as phosphorus, potassium, calcium and magnesium are easily lost, resulting in nutrient deficiency, strong acidity and poor soil structure, which is one of the important factors leading to low yield and poor quality of some fruits. In addition, the irregular use of pesticides to control pests and diseases in fruit planting has led to the gradual accumulation of pesticide residues in the soil, further destroying soil microorganisms and ecosystems. Developing conditioners that can regulate soil structure, improve microbial communities and increase soil fertility, and creating good soil conditions are of great significance for the high yield and quality of fruit trees in the south, and fertilization of dry land. As a multifunctional microorganism in the soil, actinomycetes have important application value in agricultural production. The use of actinomycetes as soil inoculants can not only increase crop yields and reduce the demand for synthetic fertilizers, but also promote overall soil health and ensure the sustainability of agriculture. Summary of the invention

[0005] The object of the present invention is to provide a microbial soil conditioner for improving soil microecological structure and promoting the growth of fruit trees. The active ingredient is the Streptomyces kunmingensis 5A2 strain, which is preserved in the Guangdong Microbial Culture Collection Center, with a preservation number of GDMCC No. 65130 and a preservation date of September 13, 2024.

[0006] Streptomyces kunmingensis 5A2 used in the present invention is an actinomycete isolated from soil. The strain is Gram-positive and has an aerobic heterotrophic nutritional type. The colonies cultured on Gao's No. 1 synthetic medium are convex, with a dry surface and neat edges. The aerial hyphae are yellow-white, and the base hyphae are yellow (see Figure 1 ). The hyphae of MS liquid culture aggregate into clumps (see Figure 2 ).

[0007] The results of 16s rDNA sequencing of the strain using primers 27F and 1492R showed that the homology with Streptomyces kunmingensis NBRC 14463 was 98.21%.

[0008] The strain has the ability to fix nitrogen and secrete iron carriers, and can also produce IAA. The actinomycetes can convert nitrogen in the atmosphere into water-soluble nitrogen sources that can be used by plants, improve soil fertility and provide nitrogen sources for the growth of other soil microorganisms. The actinomycetes have the function of secreting compounds that promote plant growth. The amylase and xylanase secreted by the actinomycetes can catalyze the conversion of starch and hemicellulose and other components in the soil into oligosaccharides, providing a carbon source for the growth of soil microorganisms while improving the water retention of the soil and the drought resistance of plants. In addition, the nitrilase and amidase secreted by the strain can efficiently catalyze the conversion of cypermethrin and 3-cyanopyridine into organic acids, convert benzonitrile into benzamide and benzoic acid, catalyze the dehydration of acrylonitrile and propionitrile, and reduce the acute toxicity of organic compounds to soil microorganisms and crops.

[0009] The beneficial effects achieved by the present invention mainly include but are not limited to the following aspects:

[0010] The microbial agent with Streptomyces kunmingensis 5A2 as the main active substance can realize multiple functions such as promoting the growth of fruit trees and improving stress resistance by increasing the activity and material metabolism of the soil microbial community, activating soil organic matter, and reducing the mechanism of pesticide residues in the soil. After testing and determination, the present invention has the function of promoting the growth of cherry tomatoes and strawberries in the seedling stage, especially significantly improving the product quality. In addition, after applying the microbial agent, the catalase activity is significantly increased, indicating that the stress resistance of the seedlings is enhanced.

[0011] In addition, through the liquid culture, solid-state fermentation and preparation processes of the present invention, the soil conditioner has the advantages of stable quality, convenient application and good storage, and has obvious practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 :Appearance colony picture of Streptomyces kunmingensis 5A2.

[0013] Figure 2 : Colony image of Streptomyces kunmingensis 5A2 in MS liquid culture with hyphae aggregated into clusters. DETAILED DESCRIPTION

[0014] Those skilled in the art can refer to the content of this article and appropriately improve the process parameters. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The products and methods of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the products and methods described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. In order to further understand the present invention, the present invention is described in detail below in conjunction with embodiments.

[0015] Example 1

[0016] The microbial soil conditioner is produced according to the following method.

[0017] (1) Preparation of solid culture medium

[0018] Mix the raw materials in the following proportions

[0019]

[0020] The solid mixture was added with water at a ratio of 2:1 (w / v), pH = 7.2-7.4, and sterilized at 121°C for 30 min. After sterilization, it was cooled to 60°C, and 5% (w / w) molasses was added and mixed evenly.

[0021] (2) Preparation of microbial inoculum

[0022] The spores of Streptomyces kunmingensis 5A2 were inoculated into MS medium and cultured in a shaking flask at 30°C and 180 rpm for 24 hours to prepare the primary seed solution. The primary seed solution was inoculated with 20% (v / v) of the inoculation amount to ferment the secondary seed solution. The medium and culture conditions were the same as the primary seed solution.

[0023] (3) Solid-state fermentation

[0024] The secondary seed liquid is inoculated onto the solid culture medium at a ratio of 1:20 (v / w). The culture medium is cultured at 30°C for 7 days, and the water content in the culture medium is maintained at 45%. After the fermentation is completed, the culture medium is naturally air-dried to obtain the microbial soil conditioner.

[0025] In the red cherry tomato plantation in western Guangdong Province, an experimental group and a control group using microbial soil conditioners were set up. The control group and the experimental group were simultaneously applied with organic fertilizers, compound urea, calcium magnesium phosphate fertilizers and potassium sulfate fertilizers. The experimental group added 250kg / mu of microbial soil conditioners in this case at one time when the seedlings were planted, and the control group added 250kg / mu of solid culture medium (without adding microorganisms). The implementation period was from August to October, and the cycle was 3 months.

[0026] Ten days after the application of microbial soil conditioner, 20 representative seedlings were selected, and the activity of catalase (CAT) was extracted and determined by the colorimetric method of the kit. Random samples were taken from the harvested fruits three times, 500 g each time, and the quality indicators related to the total sugar, total acid and solid content in the fruit were determined and analyzed by potentiometric titration (converted to citric acid), Fehling's reagent method and refractometer method. Lycopene was extracted by acetone extraction method, with a solid-liquid ratio of 1:6, 45°C and an extraction time of 120 min. The absorbance value of the extract at 502 nm was determined, and the lycopene content was calculated based on the standard curve of the concentration of the lycopene standard solution and the absorbance value. The results of the determination and analysis of relevant yield and quality indicators are shown in Table 1 below.

[0027] Table 1

[0028]

[0029] After testing and determination, the single-plant yield and per-acre yield of cherry tomatoes after the application of microbial soil conditioners increased by 19.0% and 14.5% respectively compared with the blank control. This microbial soil conditioner can promote fruit growth. Judging from the total sugar, total acid and soluble solids content and lycopene content of the harvested cherry tomatoes, the experimental group increased by 14.8%, 14.2%, 19.5% and 13.9% respectively compared with the blank control group, indicating that the application of conditioners also improved the taste quality of cherry tomatoes. In addition, the application of microbial soil conditioners significantly increased the catalase activity in the root tissue of cherry tomato seedlings, reflecting that the seedlings' resistance to environmental stress has been enhanced.

[0030] Example 2

[0031] Under the conditions of the above embodiment 1, after the fruit is harvested, the soil of the surface layer of 10 cm of the plantation experimental group and the control group is taken, and 3 points are taken from each group, and 50 g of each point is sampled and evenly mixed. The organic matter and fast-acting macroelements in the soil samples are respectively determined according to GB 9834-1988, GB7173-1988, GB9836-1988, GB 9837-1988 and other standards, and the number of microorganisms is detected by the soil suspension plate count method. The test results are shown in Table 2 below.

[0032] Table 2

[0033]

[0034] From the results, after applying the microbial soil conditioner of the present invention, the organic matter content in the soil increased by 16.4%. The microorganisms also significantly promoted the mineralization of soil nutrients, and increased the content of quick-acting nitrogen, phosphorus and potassium in the soil by 8.5%, 28.1% and 14.0%, respectively. In addition, the number of bacteria, fungi and actinomycetes in the soil increased significantly compared with the blank control, increasing by 22.9%, 38.1% and 68.4%, respectively. The soil conditioner of the present invention can improve the overall activity of microorganisms in the soil to a certain extent, thereby being conducive to the overall improvement of the soil microecological environment and the improvement of fertility.

[0035] Example 3

[0036] In a strawberry plantation in Guizhou Province, an experimental group and a control group using a microbial soil conditioner were set. The control group and the experimental group applied organic fertilizers at the same time, compounded urea, calcium magnesium phosphate fertilizer and potassium sulfate fertilizer. The experimental group added 100kg / mu of the microbial soil conditioner of the present invention at one time when transplanting. The control group used 100kg / mu of solid culture medium (without adding microorganisms). The implementation time was July-October, and the cycle was 90 days. After applying the microbial soil conditioner for 15 days, 15 representative seedlings were selected, extracted and the activity of catalase (CAT) was determined by a kit colorimetric method. A total of 1000g was randomly sampled and mixed from the harvested fruits. After adding an equal volume of distilled water homogenate, the quality indicators related to total sugar, total acid and solid content in the fruit were measured and analyzed by potentiometric titration (converted with citric acid), Fehling's reagent method and refractometer method respectively. The results of the relevant yield and quality index determination and analysis are shown in Table 3 below.

[0037] Table 3

[0038]

[0039] After testing and determination, the single plant yield and per mu yield of strawberries after applying microbial soil conditioner increased by 6.0% and 7.1% respectively compared with the blank control, reflecting that the microbial soil conditioner of the present invention can promote the growth of strawberry fruit. From the total sugar and soluble solid content of the harvested strawberries, the experimental group increased by 17.1% and 24.4% respectively compared with the blank control group, indicating that the application of conditioner also improved the taste quality of strawberries. In addition, the application of microbial soil conditioner increased the catalase activity in the root tissue of strawberry seedlings by 50.1%, reflecting that the resistance of seedlings to environmental stress has been enhanced.

[0040] Example 4

[0041] Under the conditions of Example 3, after the fruit was harvested, the soil of the surface layer of 10 cm of the plantation experimental group and the control group was taken, 3 points were taken from each group, and 50 g was sampled from each point and mixed evenly. The organic matter and fast-acting macroelements in the soil samples were determined according to GB 9834-1988, GB 7173-1988, GB9836-1988, GB 9837-1988 and other standards, and the number of microorganisms was detected by the soil suspension plate count method. The test results are shown in Table 4 below.

[0042] Table 4

[0043]

[0044] It can be seen from the above that after applying the microbial soil conditioner of the present invention, the organic matter content in the soil increased by 9.5%. The microorganisms also promoted the mineralization of soil nutrients to a certain extent, and increased the content of quick-acting nitrogen, phosphorus and potassium in the soil by 4.9%, 6.0% and 8.5% respectively. In addition, the number of bacteria, fungi and actinomycetes in the soil increased significantly compared with the blank control, increasing by 42.5%, 26.7% and 100% respectively. It reflects that the soil conditioner of the present invention can significantly improve the overall activity of microorganisms in the soil, which is beneficial to the overall improvement of the soil microecological environment and the improvement of soil fertility.

[0045] Although the above describes the specific implementation of the present invention in combination with the embodiments, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that it should be clear to those skilled in the art that these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection of the present invention.

Claims

1. A microbial soil conditioner, characterized in that: The active ingredient of the soil conditioner is Streptomyces kunmingensis 5A2, which is deposited in the Guangdong Provincial Microbiological Culture Collection Center, with a deposit number of GDMCC No. 65130 and a deposit date of September 13, 2024.

2. The soil conditioner according to claim 1, characterized in that The preparation method of the soil conditioner comprises the step of subjecting the Kunming Streptomyces to solid-state fermentation.

3. The soil conditioner according to claim 2, characterized in that The preparation method of the soil conditioner comprises: inoculating the seed liquid of the Kunming Streptomyces on a solid culture medium at a ratio of 1-3:10-50 (v / w), solid-state fermenting at 30° C. for 7 days, and naturally air-drying after the fermentation to obtain the soil conditioner.

4. The soil conditioner according to claim 3, characterized in that The solid culture medium comprises soil humus, corn flour, soybean flour, wheat bran, calcium carbonate and magnesium sulfate.

5. The soil conditioner according to claim 3 or 4, characterized in that The preparation process of the solid culture medium comprises: taking soil humus, corn flour, soybean flour, wheat bran, calcium carbonate and magnesium sulfate in a certain proportion, mixing to obtain a solid mixture, adding 0.4-1.2 times by weight of water to the solid mixture, adjusting the pH to 7.2-7.4, sterilizing at 121° C. for 30 minutes, cooling to 60° C. after sterilization, adding 4-6% (w / w) molasses and mixing evenly to obtain the solid culture medium.

6. Use of the soil conditioner according to any one of claims 1 to 5 in improving soil microecological structure and / or promoting the growth of fruit trees.

7. The use according to claim 6, characterized in that: The improvement of soil microecological structure includes: 1) increasing the organic matter in the soil; 2) Promotes the mineralization of soil nutrients and increases the content of available nitrogen, phosphorus and potassium in the soil; 3) Increase the number of microorganisms in the soil; and, 4) Reduce pesticide residues in the soil.

8. The use according to claim 6, characterized in that: The method for promoting the growth of fruit trees comprises: 1) Increase fruit yield; 2) increasing the content of total sugar, total acid and soluble solids in the fruit; and, 3) Improve the resistance of seedlings to environmental stress.

9. A Kunming Streptomyces, characterized in that: The Kunming Streptomyces is Streptomyces kunmingensis 5A2, which is deposited in the Guangdong Provincial Microbiological Culture Collection Center, with a deposit number of GDMCC No. 65130 and a deposit date of September 13, 2024.

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