Compound microbial agent formula for corn seedling stage

Abstract

The invention discloses a compound microbial agent formula for a corn seedling stage, and relates to the technical field of agricultural microorganisms. The microbial agent comprises bacillus subtilis and bacillus mucilaginosus, auxin hormone sodium naphthalene acetate, chelated zinc and a pH regulator potassium fulvate are added, and humic acid powder is used as a carrier. The dry powder preparation with the particle size being smaller than or equal to 200 meshes and the suspension rate being larger than or equal to 90% is prepared through a specific fermentation technology and a bacterial liquid mixed adsorption and spray drying technology. Field trials show that the composition can increase the emergence rate of corn from 85% to 90%-93%, increase the dry weight of the root system by 30%, and reduce the incidence rate of white seedling disease by 70% or above. Microbe, chemistry and agronomy principles are fused, and the corn production problem in the arid region is systematically solved; chemical fertilizer dependence is reduced, degraded soil is restored, and green agricultural policy guidance is met; the average cost per mu is less than 100 yuan, and the method is suitable for large-scale planting and precise irrigation systems.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural microorganisms, and specifically relates to a compound microbial inoculant formula for maize seedling stage. Background Art

[0002] Traditional maize seedling management relies on chemical fertilizers and single inoculants. For example, although Bacillus subtilis can inhibit soil-borne diseases, the liquid inoculant has a short shelf life (the viable count is easily attenuated to less than 200 million CFU / g), and there is a lack of synergistic design with hormones and trace elements. In the prior art, Bacillus mucilaginosus is mostly used for potassium and phosphorus solubilization, but it is not combined with auxin hormones (such as NAA) to directionally regulate root development.

[0003] Related technical personnel engaged in the cultivation of agricultural microorganisms have found the following defects in the actual work of the prior art:

[0004] 1. Poor stability of the inoculant: The traditional liquid inoculant of Bacillus subtilis has a short shelf life, and the viable count decays by more than 50% within 3 months, and its function is single, only inhibiting soil-borne diseases;

[0005] 2. Low compatibility with drip irrigation: Commercially available inoculants generally have problems such as large particle size (>200 mesh) and pH fluctuations, which are likely to cause drip emitter blockage;

[0006] 3. Lack of synergistic design: Most existing products use single strains or simple compounding, and do not combine hormones and trace elements to form a systematic regulation plan. Therefore, we propose a compound microbial inoculant formula for maize seedling stage. Summary of the Invention

[0007] The purpose of the present invention is: to solve the problems mentioned in the above background art, the present invention provides a compound microbial inoculant formula for maize seedling stage.

[0008] The present invention specifically adopts the following technical solutions to achieve the above purpose:

[0009] A compound microbial inoculant formula for maize seedling stage, comprising: a microbial component and a hormone and nutrient regulation component, wherein, the microbial component includes: Bacillus subtilis, Bacillus mucilaginosus and a carrier; the hormone and nutrient regulation component includes: sodium naphthylacetate, chelated zinc and potassium fulvate.

[0010] Further, the viable count of Bacillus subtilis is 5×10 8 CFU / g, the viable count of Bacillus mucilaginosus is 3×10 8 CFU / g, the carrier is humic acid powder, and the specification of the humic acid powder is 80 mesh, and the pH is 6.0.

[0011] Furthermore, the concentration of sodium naphthylacetate is 0.5 ppm, the concentration of chelated zinc is 0.1%, and the concentration of potassium fulvate is 3%.

[0012] A preparation method of a compound microbial inoculant formula for maize seedling stage comprises the following steps:

[0013] S1. Fermentation culture to culture Bacillus subtilis and Bacillus mucilaginosus;

[0014] S2. Bacterial liquid mixing, mixing the bacterial liquid after the completion of culture;

[0015] S3. Concentration, concentrating the mixed bacterial liquid and adsorbing it on humic acid powder after concentration;

[0016] S4. Drying and forming, drying the concentrated liquid obtained to obtain the inoculant powder.

[0017] Furthermore, the Bacillus subtilis uses a culture medium of 50 g / L of corn flour, 35 g / L of soybean meal powder, and 12 g / L of magnesium sulfate, with the pH adjusted to 7.2 and fermented at 37°C for 30 hours.

[0018] Furthermore, the Bacillus mucilaginosus uses a culture medium of 15 g / L of sucrose and 0.3 g / L of KHPO 2 HPO 4 and is preliminarily fermented at 30°C for 12 hours and then transferred to a high-throughput oxygen condition (2.5 vvm) for continuous fermentation for 12 hours.

[0019] Furthermore, in the bacterial liquid mixing, the volume ratio of Bacillus subtilis to Bacillus mucilaginosus is 2:1, and the water content after concentration is ≤8%.

[0020] Furthermore, a centrifugal concentrator is selected for concentration.

[0021] Furthermore, spray drying technology is adopted for drying and forming to obtain a dry powder preparation with a particle size ≤200 mesh and a suspension rate ≥90%.

[0022] An application method of a compound microbial inoculant formula for maize seedling stage is to mix the obtained inoculant powder at 100 g / mu with nutrient solution at 200 g / mu, dilute it 200 times, and apply it to the maize seedling stage through a drip irrigation system.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The extracellular polysaccharide secreted by the Bacillus mucilaginosus in the present invention wraps the spores of Bacillus subtilis, reduces the water activity, inhibits its premature germination, extends the shelf life from the traditional 3 months to 12 months, and the humic acid carrier forms a protective layer after adsorbing the bacterial cells, further reducing the damage to the live bacteria caused by environmental stress.

[0025] 2. The sodium naphthylacetate of the present invention induces the roots to secrete citric acid and malic acid. Combining with the chelating effect of chelated zinc, it converts the fixed zinc in the soil into an absorbable state, and the zinc utilization rate is increased by 20% - 25%.

[0026] 3. The humic acid powder (80 mesh) of the present invention and potassium fulvate act synergistically, so that the suspension rate ≥ 90%, the particle size ≤ 200 mesh, and the dripper blockage rate is reduced to less than 5%.

[0027] 4. The present invention integrates the principles of microbiology, chemistry and agronomy to systematically solve the problems in maize production in arid areas; reduces the dependence on chemical fertilizers, repairs degraded soils, conforms to the guiding policy of green agriculture; the cost per mu is less than 100 yuan, and it is applicable to large-scale planting and precision irrigation systems. Detailed implementation manners

[0028] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0029] The present invention provides a compound microbial inoculant formula for maize seedling stage, including: a microbial component and a hormone and nutrient regulation component. Among them, the microbial component includes: Bacillus subtilis, Bacillus mucilaginosus and a carrier; the hormone and nutrient regulation component includes: sodium naphthylacetate, chelated zinc and potassium fulvate.

[0030] Bacillus subtilis, screened from maize rhizosphere soil, secretes antibacterial peptides (such as subtilin) to inhibit pathogenic bacteria, and at the same time promotes the roots to secrete organic acids, with the characteristic of high yield of antibacterial peptides;

[0031] Bacillus mucilaginosus secretes extracellular polysaccharides (such as dextran), reduces the water activity of the fermentation broth, inhibits the spore germination of Bacillus subtilis, and the shelf life is extended to 12 months. The extracellular polysaccharides secreted by Bacillus mucilaginosus significantly inhibit the premature spore germination of Bacillus subtilis, and the shelf life is extended to 1.5 times that of traditional products;

[0032] The carrier provides an organic carbon source and enhances the adsorbability of the inoculant. Its porous structure enhances the adsorption of bacterial cells, and at the same time symbiosis with beneficial bacteria promotes the formation of soil aggregate structure;

[0033] Sodium naphthylacetate stimulates the synthesis of root ethylene at a low concentration (0.5 ppm), promotes the differentiation of lateral roots and root hairs, and synergistically improves the zinc absorption efficiency with chelated zinc. Sodium naphthylacetate induces the roots to secrete organic acids, and combines with chelated zinc to increase the zinc absorption efficiency by more than 20%;

[0034] Chelated zinc, at a concentration of 0.1%, the biological utilization rate of zinc is increased by 40% compared with zinc sulfate, effectively preventing white seedling disease;

[0035] Potassium fulvate adjusts the pH of the drip irrigation solution to 5.5 - 6.5, improves the solubility of trace elements, and promotes the proliferation of bacteria as a carbon source. The humic acid carrier and potassium fulvate synergistically regulate the suspension and pH, reducing the blockage rate by 80%.

[0036] In this example, preferably, the viable count of Bacillus subtilis is 5×10 8 CFU / g, the viable count of Bacillus mucilaginosus is 3×10 8 CFU / g, the carrier is humic acid powder, and the specification of the humic acid powder is 80 mesh, with a pH of 6.0.

[0037] In this example, preferably, the concentration of sodium naphthylacetate is 0.5 ppm, the concentration of chelated zinc is 0.1%, and the concentration of potassium fulvate is 3%.

[0038] A preparation method for a compound microbial inoculant formula for maize seedling stage includes the following steps:

[0039] S1. Fermentation culture to culture Bacillus subtilis and Bacillus mucilaginosus;

[0040] S2. Bacterial liquid mixing to mix the cultured bacterial liquid;

[0041] S3. Concentration to concentrate the mixed bacterial liquid and adsorb it on humic acid powder after concentration;

[0042] S4. Drying and forming to perform drying operation on the concentrated liquid obtained to obtain the inoculant powder.

[0043] In this example, preferably, Bacillus subtilis uses a culture medium of 50 g / L of corn flour, 35 g / L of soybean meal powder, and 12 g / L of magnesium sulfate, with the pH adjusted to 7.2 and fermented at 37°C for 30 hours.

[0044] In this example, preferably, Bacillus mucilaginosus uses a culture medium of 15 g / L of sucrose and 0.3 g / L of KH 2 HPO 4 Ferment initially at 30°C for 12 hours and then transfer to a high-oxygen condition (2.5 vvm) for continuous fermentation for 12 hours.

[0045] In this example, preferably, the volume ratio of Bacillus subtilis to Bacillus mucilaginosus in the bacterial liquid mixing is 2:1, and the water content after concentration is ≤8%.

[0046] In this example, preferably, a centrifugal concentrator is used for concentration.

[0047] In this example, preferably, spray drying technology is used for drying and forming to obtain a dry powder preparation with a particle size ≤200 mesh and a suspension rate ≥90%.

[0048] An application method of a compound microbial inoculant formula for corn seedling stage is to mix the prepared inoculant powder at 100 g / mu with the nutrient solution at 200 g / mu, and apply it to the corn seedling stage through a drip irrigation system after diluting 200 times.

[0049] Experiment

[0050] 1. Optimization experiment of inoculant preparation:

[0051] 1). Screening of strain ratio: Comparing the volume ratios of Bacillus subtilis and Bacillus mucilaginosus (1:1, 2:1, 3:1), it is found that the preservation period is the longest (12 months) when the ratio is 2:1, and the attenuation rate of viable bacteria number is <10%.

[0052] 2). Carrier optimization: Testing humic acid, diatomite, and bentonite carriers, the humic acid (pH 6.0) has the highest cell adsorption rate (95%), and the suspension rate ≥90%.

[0053] 2. Extended data of field application:

[0054] Regional adaptability: Experiments in arid areas of Ningxia: After drip irrigation, the soil water content increased by 15%, and the emergence rate was 92% (80% in the control group); Experiments in semi-arid areas of Gansu: The incidence of white seedling disease decreased from 25% to 7%, and the zinc content in the roots increased by 18%.

[0055] 5. Long-term soil effect

[0056] After continuous application, the soil organic matter content increased from 1.2% to 1.8%, the pH decreased from 8.5 to 7.2, and the salinization degree decreased significantly.

[0057] Verified through laboratory simulation and field experiments (arid areas such as Ningxia and Gansu), it has the following advantages:

[0058] 1. Emergence rate and root development:

[0059] Emergence rate: 90% - 93% in the treatment group (85% in the control group);

[0060] Dry weight of roots: Increased by 30%, and the main root length increased by 25% - 35%.

[0061] 2. Disease resistance and soil improvement:

[0062] The incidence of white seedling disease decreased significantly, and the available phosphorus and potassium contents in the soil increased by 15% and 12% respectively;

[0063] The soil microbial diversity index (Shannon index) increased by 1.2 times, and the abundance of pathogenic bacteria (such as Fusarium) decreased by 60%.

[0064] 3. Economic benefits:

[0065] Reduce the amount of chemical fertilizer used by 10% - 30% and increase the yield by 7% - 15%.

[0066] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A composite microbial agent formulation for corn seedlings, characterized in that: include: Microbial components and hormone and nutritional regulation components, wherein the microbial components include: Bacillus subtilis, Bacillus gelatinus and a carrier; the hormone and nutritional regulation components include: sodium naphthylacetate, chelated zinc and potassium fulvic acid.

2. The composite microbial agent formulation for corn seedlings according to claim 1, characterized in that: The viable count of the Bacillus subtilis is 5×10 8 CFU / g, the viable count of the jelly-like Bacillus was 3×10 8 CFU / g, the carrier is humic acid powder, and the specification of the humic acid powder is 80 mesh and the pH is 6.

0.

3. The composite microbial agent formulation for corn seedlings according to claim 1, characterized in that: The concentration of the sodium naphthylacetate is 0.5 ppm, the concentration of the chelated zinc is 0.1%, and the concentration of the potassium humate is 3%.

4. A method for preparing a composite microbial agent formula for corn seedlings, characterized in that: The steps include: S1, fermentation culture, culturing Bacillus subtilis and Bacillus jelly; S2, mixing the bacterial solution, mixing the cultured bacterial solution; S3, concentrating, concentrating the mixed bacterial solution, and adsorbing the concentrated bacterial solution onto humic acid powder; S4, drying and molding, drying the obtained concentrated liquid to obtain bacterial agent powder.

5. The method for preparing a composite microbial agent formula for corn seedlings according to claim 4, characterized in that: The Bacillus subtilis is grown in a culture medium containing 50 g / L corn flour, 35 g / L soybean meal, and 12 g / L magnesium sulfate, with the pH adjusted to 7.2 and fermented at 37° C. for 30 hours.

6. The method for preparing a composite microbial agent formula for corn seedlings according to claim 4, characterized in that: The gelatinous Bacillus was fermented in a medium containing 15 g / L sucrose and 0.3 g / L K2HPO4. The culture medium was initially fermented at 30°C for 12 hours and then transferred to a high oxygen condition (2.5 vvm) to continue fermenting for 12 hours.

7. The method for preparing a composite microbial agent formula for corn seedlings according to claim 4, characterized in that: The volume ratio of Bacillus subtilis to Bacillus gelatinus in the bacterial liquid mixture is 2:1, and the water content after concentration is ≤8%.

8. The method for preparing a composite microbial agent formula for corn seedlings according to claim 4, characterized in that: The concentration is carried out using a centrifugal concentrator.

9. The method for preparing a composite microbial agent formula for corn seedlings according to claim 4, characterized in that: The drying and molding adopts spray drying technology to obtain a dry powder preparation with a particle size of ≤200 meshes and a suspension rate of ≥90%.

10. An application method of a composite microbial agent formula for corn seedlings, characterized in that: The prepared microbial agent powder was mixed at 100 g / mu with nutrient solution at 200 g / mu, diluted 200 times and then applied to corn seedlings through a drip irrigation system.