Remediation fungicide for relieving continuous cropping obstacles of soil

Abstract

The invention belongs to the technical field of microbial agents, and discloses a remediation microbial agent for relieving continuous cropping obstacles of soil. According to the invention, the fermentation bacteria liquid of bradyrhizobium and pseudomonas fluorescens is mixed with the carrier auxiliary agent to prepare the remediation microbial agent, and the remediation microbial agent can reduce the content of organic acid in soil, improve the root activity, obviously improve the cotton yield, promote growth and increase the yield. In addition, the repairing microbial agent can also reduce the morbidity of fusarium wilt and verticillium wilt of cotton, and is a continuous cropping obstacle repairing material with excellent application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial agents and discloses a repair agent for alleviating soil continuous cropping obstacles. Background Art

[0002] The cotton planting pattern is single and the continuous cropping phenomenon is serious, which leads to continuous cropping problems, causing certain negative impacts on the soil environment of cotton fields, and even becomes the main reason restricting the development of the cotton industry.

[0003] Studies have shown that the main causes of soil continuous cropping problems are as follows: first, cotton prefers to absorb certain elements during its growth process, resulting in a deficiency of certain elements in the soil; second, cotton releases certain metabolites such as phenols, terpenes, and nitrogen-containing compounds into the soil through its roots, resulting in an increase in the content of secondary metabolites in the soil; in addition, the large-scale use of chemical fertilizers and pesticides may also lead to crop continuous cropping problems, including various insecticides, fungicides, herbicides, ripening agents, etc., and in production practice, there is usually no upper limit on the use of chemical fertilizers and pesticides.

[0004] Long-term continuous cropping reduces the diversity of cotton rhizosphere soil microbial communities, leading to an imbalance in the microbial flora, an increase in pathogenic soil microorganisms, and a decrease in beneficial bacteria, which in turn leads to soil-borne diseases such as cotton wilt and Verticillium wilt. Sometimes, even if cotton fields remain disease-free, overall cotton growth may be poor, and fertilization or irrigation measures may be ineffective. Therefore, cotton yield reductions caused by continuous cropping seriously impact farmers' economic benefits, necessitating soil restoration to mitigate the yield reductions caused by continuous cropping. Summary of the Invention

[0005] To address cotton yield losses caused by soil barriers during continuous cotton cropping and improve soil health, the present invention provides a remediation agent that alleviates soil barriers. The remediation agent can improve cotton plant growth, enhance root vitality, and reduce the occurrence of soil-borne diseases. To achieve this technical effect, the present invention provides the following technical solution:

[0006] The present invention first provides a repair bacterial agent for alleviating soil continuous cropping obstacles. The active ingredients of the repair bacterial agent are: Bradyrhizobium and Pseudomonas fluorescens.

[0007] Furthermore, the repair bacterial agent is prepared by mixing a carrier with a mixed fermentation liquid and then drying it, wherein, by mass percentage, the carrier is 75% and the mixed fermentation liquid is 25%;

[0008] Among them, 75% of the carrier includes: 25% kaolin, 25% diatomaceous earth, and 25% white carbon black;

[0009] The components of the mixed fermentation liquid are as follows: by volume ratio, Bradyrhizobium fermentation liquid: Pseudomonas fluorescens fermentation liquid = 1:1.

[0010] Furthermore, the remediation bacterial agent is used in cotton continuous cropping plots.

[0011] In a second aspect, the present invention further provides a method for preparing the repair bacterial agent, which can be prepared by the following method:

[0012] Activated Bradyrhizobium and Pseudomonas fluorescens colonies were obtained by streaking culture on PDA medium at 28°C for 72 hours.

[0013] The hyphae on the PDA medium were picked and inoculated into sterilized LB liquid medium, and cultured at 28°C and 180 rpm for 3 days to obtain the seed liquid of Bradyrhizobium and the seed liquid of Pseudomonas fluorescens, respectively;

[0014] The two seed liquids were added at a rate of 1% to sterilized LB liquid medium, respectively, and cultured at 28°C and 180 rpm for 5 days to obtain fermentation liquids of Bradyrhizobium and Pseudomonas fluorescens.

[0015] The two fermentation broths were mixed in a volume ratio of 1:1 to obtain a mixed fermentation broth;

[0016] The solid bacterial agent is obtained by mixing 25% of kaolin, 25% of diatomaceous earth, 25% of white carbon black and 25% of mixed fermentation liquid in percentage by mass, and drying the mixture at 25-35° C.

[0017] In a third aspect, the present invention seeks to protect the use of the repair bacterial agent in enhancing the root vitality of cotton plants.

[0018] Fourthly, the present invention seeks to protect the use of the repair bacteria agent in increasing cotton yield.

[0019] In a fifth aspect, the present invention seeks to protect the use of the remediation bacterial agent in reducing the content of organic acids in soil. Specifically, the soil organic acids include ferulic acid, protocatechuic acid, and vanillic acid.

[0020] In a sixth aspect, the present invention seeks to protect the use of the remediation bacterial agent in reducing the incidence of soil-borne diseases of cotton. Specifically, the soil-borne diseases include cotton wilt and cotton verticillium wilt.

[0021] Compared with the prior art, the present invention's "a remediation bacterial agent for alleviating soil continuous cropping obstacles" has the following beneficial effects:

[0022] The repair bacterial agent provided by the present invention has an excellent improvement effect on the cotton yield reduction and poor plant growth caused by continuous cropping, can significantly improve the cotton plant height and the number of fruit branches, and ensure the cotton yield in the continuous cropping cotton plots.

[0023] The remediation agent provided by the present invention can significantly enhance the root vitality of cotton plants. Root vitality directly affects cotton's ability to absorb water and nutrients, which in turn affects cotton's photosynthetic efficiency and yield. By improving the root vitality of cotton plants, the remediation agent indirectly increases cotton yield and reduces the adverse effects of continuous cropping on cotton.

[0024] The remediation bacterial agent provided by the present invention has an alleviating effect on the increase in soil organic acid content caused by continuous cropping, and can effectively reduce the content of ferulic acid, protocatechuic acid, and vanillic acid in the soil.

[0025] The repair bacterial agent provided by the present invention reduces the incidence of soil-borne diseases such as cotton wilt and verticillium wilt, indicating that the bacterial agent has a significant effect on regulating the distribution of soil flora, enriching beneficial soil bacteria, and reducing harmful soil bacteria.

[0026] The repair bacterial agent provided by the present invention is formed by compounding Bradyrhizobium and Pseudomonas fluorescens. The two bacteria do not produce antagonism and have good compatibility. They can promote the growth of cotton from different pathways. It is a biological bacterial agent with broad application prospects. DETAILED DESCRIPTION

[0027] The technical solutions of the present invention are described clearly and completely below with reference to the embodiments. It is obvious that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0028] Unless otherwise specified, the experimental methods in the following examples are conventional methods and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples are all commercially available unless otherwise specified.

[0029] In each embodiment of the present invention, Bradyrhizobium was purchased from Shanghai Lianzu Biotechnology Co., Ltd.; Pseudomonas fluorescens was purchased from Ningbo Mingzhou Biotechnology Co., Ltd.

[0030] Example 1

[0031] This example provides a test on the symbiotic ability of Bradyrhizobium and Pseudomonas fluorescens.

[0032] Bradyrhizobium and Pseudomonas fluorescens were inoculated into the same culture medium and a plate confrontation test was conducted to determine whether the two could coexist by observing the growth of the colonies. The specific operation is as follows:

[0033] Strain activation: Bradyrhizobium and Pseudomonas fluorescens stored at low temperature were taken out respectively, and streaked on PDA medium and cultured at 28°C for 72 hours until colonies grew.

[0034] Symbiotic Competence Test: Activated bacterial clumps (5 mm in diameter) were harvested and inoculated on both sides of a new PDA plate. After inoculation, the plates were incubated at 28°C for 3 days and the colonies observed for growth. The growth of Bradyrhizobium and Pseudomonas fluorescens was observed. The absence of mutually antagonistic inhibition zones indicated symbiotic compatibility.

[0035] Symbiotic ability tests have shown that the Bradyrhizobium and Pseudomonas fluorescens can coexist and have good compatibility, and have the potential to be prepared into a composite bacterial agent.

[0036] Example 2

[0037] This example describes the preparation of a bacterial agent using Bradyrhizobium and Pseudomonas fluorescens.

[0038] Strain activation: Bradyrhizobium and Pseudomonas fluorescens stored at low temperature were taken out respectively, and streaked on PDA medium and cultured at 28°C for 72 hours until colonies grew.

[0039] Preparation of inoculum: Mycelia on PDA medium were picked separately and inoculated into sterilized LB liquid medium with an inoculation amount of 1%. The culture was shaken at 28°C and 180 rpm for 3 days to obtain seed liquid of Bradyrhizobium and seed liquid of Pseudomonas fluorescens.

[0040] The seed solution was added at a rate of 1% to sterilized LB liquid medium and cultured at 28°C and 180 rpm for 5 days to obtain fermentation liquids of Bradyrhizobium and Pseudomonas fluorescens. The two fermentation liquids were mixed at a volume ratio of 1:1 to obtain a mixed fermentation liquid.

[0041] The mixed fermentation liquid is mixed with the solid auxiliary materials. The specific method is as follows: 500g of kaolin, 500g of diatomaceous earth, 500g of white carbon black, 500g of mixed fermentation liquid, mixed evenly, and dried at 30°C to obtain a solid bacterial agent.

[0042] Example 3

[0043] This example provides a potted plant experiment on the effect of the bacterial agent on improving continuous cropping problems in cotton.

[0044] Experimental soil: A plot with obvious cotton continuous cropping obstacles in Awati County, Xinjiang was selected as the source of experimental soil. The plot has a history of 8 years of continuous cropping.

[0045] Test method: Cotton plants were cultivated in soil mixed with microbial agents and soil without microbial agents, and the growth of seedlings was compared. The details are as follows:

[0046] Experimental group: 500 g of soil was placed in each of the 9 pots, 3% (15 g) of Bradyrhizobium agent was added to the soil of pots 1 to 3, 3% (15 g) of Pseudomonas fluorescens agent was added to the soil of pots 4 to 6, and 3% (15 g) of the composite agent prepared by the method of Example 1 was added to the soil of pots 7 to 9.

[0047] Control group: 500 g of soil was placed in each of the three pots without adding any bacterial agents.

[0048] The preparation method of the Bradyrhizobium agent and the Pseudomonas fluorescens agent is similar to that of Example 2, except that when the fermentation broth is mixed with the solid auxiliary material, the mixed fermentation broth is replaced by a single strain fermentation broth, and the remaining steps are the same.

[0049] Two plump cotton seeds were sown in each pot in the experimental and control groups. Both groups were given the same water and fertilizer management conditions and cultured under 10 hours of light and 14 hours of darkness for 30 days. The growth of the cotton seedlings in the experimental and control groups was observed. Plant height, root length, and soil organic acid content (ferulic acid, protocatechuic acid, and vanillic acid) were measured in both groups. Results are presented as averages.

[0050] Test results: See Table 1.

[0051] Table 1. Index determination of each group in the potted plant experiment

[0052]

[0053] As shown in Table 1, compared with the control group, the average plant height and root length of cotton seedlings were improved after the inoculation of Bradyrhizobium and Pseudomonas fluorescens, and the content of ferulic acid, protocatechuic acid, and vanillic acid in the soil decreased significantly. The group incorporating the composite inoculant was superior to the single-species inoculant. This indicates that the combination of Bradyrhizobium and Pseudomonas fluorescens has the best effect in alleviating continuous cropping problems.

[0054] Example 4

[0055] This example provides a field test of the effect of the bacterial agent on improving continuous cropping obstacles in cotton.

[0056] Experimental location: Awati County, Xinjiang.

[0057] Trial time: April 2023 to September 2023.

[0058] Experimental method: A plot of cotton with obvious continuous cropping obstacles in Awati County, Xinjiang was selected as the experimental site. The plot has an 8-year history of continuous cropping. The experimental group used microbial agents during sowing, while the control group did not use microbial agents during sowing.

[0059] Cotton plants were cultivated in soil with added microbial agents and in ordinary continuous cropping soil, and the growth of seedlings was compared. The details are as follows:

[0060] Experimental groups: Bradyrhizobium inoculated into the soil of groups 1 to 3, Pseudomonas fluorescens inoculated into the soil of groups 4 to 6, and a composite inoculated into the soil of groups 7 to 9. Each group had 10 replicates, and each seedling was inoculated with 3% (15g) of the inoculated into the soil.

[0061] Control group: No fungal agent was used and 10 seedlings were sown.

[0062] The experimental and control groups were given identical water and fertilizer management conditions, and the growth of cotton seedlings in both groups was observed. Plant height, root activity (using the TTC method), and soil organic acid content (ferulic acid, protocatechuic acid, and vanillic acid) were measured 30 days after sowing. The incidence of Fusarium wilt and Verticillium wilt in both groups was calculated throughout their growth, and the yield per plant and the number of fruiting branches were calculated after harvest. Incidence = number of diseased plants / total number of plants in the experimental group. Results are expressed as mean values.

[0063] Table 2. Average plant height, root activity and soil organic acid content of each group in the field experiment

[0064]

[0065]

[0066] Table 3. Disease incidence, yield per plant, and number of fruit branches at harvest

[0067]

[0068] Tables 2 and 3 show the cotton growth and harvest conditions of the experimental group and the control group, respectively. As shown in Table 2, the single-species Bradyrhizobium agent and Pseudomonas fluorescens agent are better than the control group, and the composite agent is better than the single-species agent. The composite agent can significantly promote the growth of cotton plants, improve root vitality, reduce the organic acid content in the soil, and help cotton plants resist diseases, and has a significant alleviating effect on cotton continuous cropping obstacles. Compared with the control group, the composite agent can also significantly increase cotton yield, with an obvious yield-increasing effect.

[0069] The embodiments described above are only some of the embodiments of the present invention, not all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but merely represents selected embodiments of the present invention. All other embodiments obtained without creative effort and through deduction and substitution by a person of ordinary skill in the art based on the concept of the present invention are within the scope of protection of the present invention.

Claims

1. A soil remediation agent for alleviating continuous cropping obstacles, characterized in that: The active ingredients of the repair bacterial agent are: Bradyrhizobium and Pseudomonas fluorescens.

2. The repair bacterial agent according to claim 1, characterized in that The repair bacterial agent is prepared by mixing a carrier with a mixed fermentation liquid and then drying it, with the carrier being 75% and the mixed fermentation liquid being 25% by mass. Among them, 75% of the carrier includes: 25% kaolin, 25% diatomaceous earth, and 25% white carbon black; The components of the mixed fermentation liquid are as follows: by volume ratio, Bradyrhizobium fermentation liquid: Pseudomonas fluorescens fermentation liquid = 1:

1.

3. The repair bacterial agent according to claim 1, characterized in that The remediation bacterial agent is used for cotton continuous cropping plots.

4. The preparation method of the repair bacterial agent according to claim 1, characterized in that: The preparation method comprises: Activated Bradyrhizobium and Pseudomonas fluorescens colonies were obtained by streaking culture on PDA medium at 28°C for 72 hours. The hyphae on the PDA medium were picked and inoculated into sterilized LB liquid medium, and cultured at 28°C and 180 rpm for 3 days to obtain the seed liquid of Bradyrhizobium and the seed liquid of Pseudomonas fluorescens, respectively; The two seed liquids were added at a rate of 1% to sterilized LB liquid medium, respectively, and cultured at 28°C and 180 rpm for 5 days to obtain fermentation liquids of Bradyrhizobium and Pseudomonas fluorescens. The two fermentation broths were mixed in a volume ratio of 1:1 to obtain a mixed fermentation broth; The solid bacterial agent is obtained by mixing 25% of kaolin, 25% of diatomaceous earth, 25% of white carbon black and 25% of mixed fermentation liquid in percentage by mass, and drying the mixture at 25-35° C.

5. Use of the repair bacterial agent according to claim 1 in improving the root activity of cotton plants.

6. Use of the repair bacterial agent according to claim 1 in increasing cotton yield.

7. Use of the remediation bacterial agent according to claim 1 in reducing the organic acid content in soil, characterized in that: The soil organic acids include ferulic acid, protocatechuic acid and vanillic acid.

8. Use of the remediation bacterial agent according to claim 1 in reducing the incidence of soil-borne diseases in cotton, characterized in that: The soil-borne diseases include cotton wilt and cotton verticillium wilt.

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