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CN-121986696-A - Special microbial agent application method for improving nitrogen fixation efficiency of soybean root nodule

CN121986696ACN 121986696 ACN121986696 ACN 121986696ACN-121986696-A

Abstract

The invention relates to a special microbial agent application method for improving nitrogen fixation efficiency of soybean rhizomes, and belongs to the field of agricultural microbial application. The core strategy of the staged time sequence application is that first, a first composite microbial agent containing proline secreting bacteria and indigenous mixed bacteria inhibiting bacteria is applied to soil before or during sowing, a pre-culture period of 5-15 days is passed, proline is converted into indole-3-acetic acid (IAA) by fourth microorganisms which exist synchronously or are introduced, so that a growth promoting microenvironment is established in rhizosphere, meanwhile, harmful mixed bacteria are inhibited by the third microorganisms, and then slow-growing rhizobia or sinorhizobia are applied to seedlings or rhizosphere. The time sequence design creates an optimized colonization niche with low competition and high chemotaxis signals for the target rhizobia by improving the environment and then introducing a synergistic mechanism of strains. The method can obviously improve the infection success rate of rhizobia, increase the number of rhizobia and the activity of the nitrogen fixation enzyme, synchronously promote the growth of soybean root systems, and improve the symbiotic nitrogen fixation efficiency and yield of soybean.

Inventors

  • Leng Xiangya

Assignees

  • 冷向亚
  • 郭中宇

Dates

Publication Date
20260508
Application Date
20260305

Claims (10)

  1. 1. The application method of the special microbial agent for improving the nitrogen fixation efficiency of the soybean root nodule is characterized by comprising the following steps of: S1, applying a first composite microbial agent containing a first microorganism and a third microorganism into soil of a soybean sowing area, wherein the first microorganism can synthesize and secrete proline, and the third microorganism can inhibit indigenous miscellaneous bacteria which form a living threat to rhizobia; S2, allowing the first composite microbial inoculum to act in soybean rhizosphere soil for a pre-culture period after the first composite microbial inoculum is applied, wherein the pre-culture period is 5 to 15 days; S3, after the pre-culture period, applying a second microbial agent comprising a second microorganism to the soybean plant or rhizosphere soil, wherein the second microorganism is rhizobium chrobium or rhizobium sinorhizobium; In the pre-culture period, proline accumulated by the first microorganism in the rhizosphere is utilized by fourth microorganism which is additionally introduced into soil and can be used for synthesizing indole-3-acetic acid by utilizing proline, so that a growth-promoting microenvironment rich in indole-3-acetic acid is established in the rhizosphere, meanwhile, the third microorganism has an inhibition effect on indigenous bacteria, and the establishment of the growth-promoting microenvironment and the cooperation of the inhibition effect together create an optimal condition for efficient colonization and nodulation of the second microorganism.
  2. 2. The method of claim 1, wherein the first microorganism is a strain selected from the group consisting of bacillus amyloliquefaciens, bacillus siamensis, and bacillus licheniformis.
  3. 3. The method of claim 1, wherein the third microorganism is a strain selected from the group consisting of bacillus subtilis, bacillus pumilus, and trichoderma harzianum.
  4. 4. The method according to claim 1, wherein in step S1, the fourth microorganism is a non-pathogenic yeast or bacterium capable of synthesizing indole-3-acetic acid from proline as a precursor, and the first complex microbial agent is co-applied or sequentially applied to soil.
  5. 5. The method according to claim 4, wherein the fourth microorganism is a strain selected from Saccharomyces cerevisiae or Kluyveromyces marxianus.
  6. 6. The method according to claim 1, wherein in the step S1, the first composite microbial agent is applied in a ditch application, a hole application or a mixed application with a base fertilizer, and the effective viable count of the first microbial agent is not less than 1x 10-8 cfu/gram of soil.
  7. 7. The method according to claim 1, wherein in step S3, the second microbial agent is applied in the form of a seed pelleting coating, a seedling rooting or a soil mixing with a sowing ditch.
  8. 8. The method of claim 1, wherein the soil temperature is maintained at 15 ℃ to 30 ℃ and the soil moisture content is maintained at 60% to 80% of the field capacity during the pre-incubation period.
  9. 9. A dedicated microbial inoculant system for carrying out the method of any one of claims 1-8, the system comprising: a first individual packaging unit comprising a formulation of the first microorganism and the third microorganism; A second individual packaging unit comprising a formulation of the second microorganism; And instructions for use indicating that the formulation of the first individually packaged unit is to be applied prior to or at the time of sowing the soybeans and the formulation of the second individually packaged unit is to be applied after a pre-incubation period of 5 to 15 days apart.
  10. 10. The microbial inoculant system according to claim 9, wherein the system further comprises: a third individual packaging unit comprising a formulation of a fourth microorganism according to claim 4 or 5; The instructions further indicate that the formulation of the third individual packaging unit is co-administered or sequentially administered with the formulation of the first individual packaging unit.

Description

Special microbial agent application method for improving nitrogen fixation efficiency of soybean root nodule Technical Field The invention relates to the technical field of agricultural microorganism application, in particular to a special microbial agent application method for improving nitrogen fixation efficiency of soybean rhizomes. Background Soybean (Glycine max) is an important food and oil crop, and about 50% -60% of the nitrogen required in the growth process is derived from symbiotic nitrogen fixation with rhizobia. Therefore, inoculating high-efficiency rhizobia agents is a key agronomic measure for improving soybean yield and reducing chemical nitrogen fertilizer dependence. The single or composite rhizobia agent is widely used in production at present, and the inoculation mode is seed coating, ditch application or mixed application with base fertilizer, aiming at directly introducing a large amount of living bacteria into rhizosphere so as to realize high-efficiency nodulation. However, in practical agricultural production, the effects of such vaccination regimes often exhibit significant instability. The root cause is that the introduced exogenous rhizobia is faced with a complex and competitive microbial ecological environment immediately after entering the soil, on the one hand, the indigenous microbial communities (including some competitive bacteria and fungal pathogenic bacteria) in the soil may have strong competitive or antagonistic effect on the colonization of the rhizobia, and on the other hand, the physicochemical properties of the soil (such as pH, organic matter content) and early root development status of the crop may not be sufficient to provide the best chemical signals and nutritional microenvironment required by the rhizobia to effectively identify the host, initiate the infestation procedure. In particular, the concentration of signal molecules such as indole-3-acetic acid (IAA) secreted by plant roots in early stage is insufficient, and it is difficult to form an effective chemotactic gradient in rhizosphere to guide the directional movement and enrichment of rhizobia. To solve the above problems, some improvements have been made in the prior art, such as development of a composite microbial agent comprising rhizobia and growth-promoting bacteria (e.g., phosphate-solubilizing bacteria, hormone-producing bacteria), or addition of nutritional aids to the microbial agent. These methods improve the survival conditions of rhizobia to some extent or provide additional growth stimulation. But it is still essentially a "static" combination strategy in which microorganisms of different functions are applied in admixture with the material at the same point in time. In the early stage of soil application, resources and space violent competition still can be exploded immediately between different microorganisms and between exogenous bacteria and indigenous bacteria, the synergistic effect of functional strains is weakened or even counteracted in the initial competition stage, and it is difficult to ensure that rhizobia can preferentially acquire and occupy the most favorable infection sites. In summary, the prior art has not systematically solved the core problem of how to create a specific infection channel with low competitive pressure and high chemotactic signal for rhizobia in advance in time and space. Therefore, an inoculation method capable of actively regulating and controlling establishment time sequence of rhizosphere microbial communities and constructing an optimized ecological niche beneficial to target rhizobium colonization in a staged manner is developed, and the inoculation method has urgent technical requirements and important application value for realizing stability and remarkable improvement of soybean symbiotic nitrogen fixation efficiency. Disclosure of Invention The invention provides a special microbial agent application method for improving nitrogen fixation efficiency of soybean rhizomes, aiming at solving the problems in the prior art. In order to solve the technical problems, the invention is realized by the following technical scheme that in the first aspect, the special microbial agent application method for improving the nitrogen fixation efficiency of the soybean root nodule comprises the following steps in sequence: S1, applying a first composite microbial agent containing a first microorganism and a third microorganism into soil of a soybean sowing area, wherein the first microorganism can synthesize and secrete proline, and the third microorganism can inhibit indigenous miscellaneous bacteria which form a living threat to rhizobia; S2, allowing the first composite microbial inoculum to act in soybean rhizosphere soil for a pre-culture period after the first composite microbial inoculum is applied, wherein the pre-culture period is 5 to 15 days; S3, after the pre-culture period, applying a second microbial agent comprising a second microorganism to t