Compound microbial agent for improving yield and quality of peanuts and preparation method of compound microbial agent

Abstract

The invention belongs to the technical field of microorganisms, and relates to a compound microbial agent for improving the yield and quality of peanuts and a preparation method of the compound microbial agent. The compound microbial agent for improving the yield and the quality of the peanuts comprises three functional strains, namely, dinitrogen bradyrhizobium, bacillus paralicheniformis and pseudomonas plecoglossicida, and the three strains are mixed according to the volume ratio of 2: 1: 1 and then cooperate with one another, so that the compound microbial agent has higher adaptability to the complex environment of rhizosphere, and the yield and the quality of the peanuts are remarkably improved. Meanwhile, the microbial carrier is added into the microbial agent, so that the action time and the stability of the compound microbial agent are effectively improved. The compound microbial agent effectively improves the agronomic characters of peanut plants, increases the peanut yield, improves the peanut quality, reduces the application amount of chemical fertilizers, and improves the economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a composite microbial agent for improving peanut yield and quality and a preparation method thereof. Background Art

[0002] Peanuts are a food with high nutritional value, rich in protein, fat, carbohydrates, vitamins (such as A, B6, E, K) and minerals (such as calcium, phosphorus, iron). Peanuts are rich in unsaturated fatty acids, lecithin and vitamin E, and have health benefits such as lowering cholesterol and anti-aging. In addition, peanuts also contain a variety of amino acids and bioactive substances, such as flavonoids and phenolic compounds, which have antioxidant, anti-inflammatory, blood pressure lowering and anti-cancer effects. Peanuts can be eaten raw, fried, boiled or made into peanut butter. Peanut oil is one of the important vegetable oils with a high smoke point and is suitable for cooking. Peanuts are also widely used in the production of food, medicine, cosmetics, and as feed and chemical raw materials, so there is a great demand for peanuts.

[0003] For a long time, the increase in peanut production has mainly relied on the large-scale use of chemical fertilizers in addition to the replacement of varieties. The use of a large amount of chemical fertilizers has increased peanut production, but it also brings a series of negative effects. For example, unreasonable application of chemical fertilizers will inhibit the growth and development of crops and the decline in quality, and with the increase in the number of years of application, it will also cause a series of negative effects such as soil compaction, soil acidification, and decreased fertilizer utilization. With the advancement of my country's weight loss action plan, biological agents have played an important role in agricultural production. Microbial agents contain a large number of functional microorganisms. During the production process, the application of microbial fertilizers can improve the number and structure of rhizosphere soil microbial communities, enrich the types, number and activity of soil microorganisms, improve the physical and chemical properties of the soil, and effectively activate the phosphorus and potassium nutrients fixed by the soil, which plays a role in improving soil structure, increasing soil fertilizer efficiency, and reducing the occurrence of diseases and insect pests. At the same time, it overcomes the shortcomings of soil compaction, agricultural product quality decline, and slow fertilizer efficiency of organic fertilizers caused by long-term and large-scale application of chemical fertilizers. Therefore, microbial agents have become one of the important ways to replace chemical fertilizers. Summary of the invention

[0004] The main purpose of the present invention is to provide a composite microbial agent, which can promote the increase of peanut nodules, improve peanut yield and peanut quality, and reduce the input of chemical fertilizers.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A composite microbial agent for improving peanut yield and quality, comprising Bradyrhizobium diazoefficiens, Bacillus paralicheniformis and Pseudomonas plecoglossicida.

[0007] Further, the dinitrogen bradyrhizobium strain number is CGMCC No.1.15566, purchased from China General Microorganism Collection Center, and the original preservation date is December 30, 2015; the paralicheniformis strain number is CGMCC No.1.15832, purchased from China General Microorganism Collection Center, and the original preservation date is September 20, 2016; the Pseudomonas ayuensis strain number is CGMCC No.1.16111, purchased from China General Microorganism Collection Center, and the original preservation date is March 29, 2017. The three strains used in the present invention can be purchased by querying in the strain catalog of China General Microorganism Collection Center, without repeated biological preservation.

[0008] A method for preparing a composite microbial agent for improving peanut yield and quality comprises the following steps:

[0009] S1: Thaw the dinitrogen bradyrhizobium and activate it in LB solid medium. Then pick a single colony of dinitrogen bradyrhizobium and inoculate it into liquid nitrogen-fixing medium. Cultivate it at 28°C and 170 r / min until OD600 = 0.6 to obtain seed solution. Inoculate 1% of the seed solution into 200 mL liquid nitrogen-fixing medium and cultivate it at 28°C and 170 r / min. Use the dilution plate method to detect the number of active bacterial colonies. 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a dinitrogen Bradyrhizobium bacterial solution;

[0010] S2: Bacillus paralicheniformis and Pseudomonas ayuensis were thawed and activated in nutrient broth agar medium, and single colonies of Bacillus paralicheniformis and Pseudomonas ayuensis were selected and inoculated into nutrient broth liquid medium, respectively, and cultured at 30°C and 200 r / min until OD600 = 0.6 to obtain seed solution, and then 1% of the seed solution was inoculated into 200 mL nutrient broth liquid medium and cultured at 30°C and 200 r / min, and the activity of the bacterial solution colonies was detected by the dilution plate method, and the number of colonies reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a bacterial solution of Bacillus paralicheniformis and Pseudomonas ayutans;

[0011] S3: mixing the three bacterial solutions in a volume ratio of 2:1:1 to obtain a mixed bacterial solution;

[0012] S4: Evenly mix the polygonatum odoratum extract and chitosan, then add 40-mesh corn cob biochar and stir evenly to obtain a microbial carrier; drop the mixed bacterial solution into the continuously stirred microbial carrier, and dry it after the dropwise addition is completed to obtain a microbial agent.

[0013] Furthermore, the composition of the liquid nitrogen fixation medium in step S1 is: KH2PO4 0.2g, K2HPO4 0.8g, MgSO4·7H2O 0.2g, CaSO4·2H2O 0.1g, FeCl3 0.1g, Na2MoO4·2H2O 0.1g, yeast extract 0.5g, mannitol 20g, distilled water 1L, and the pH is adjusted to 7.2; the composition of the nutrient gravy liquid medium in step S2 is: peptone 10g, beef extract 3g, NaCl 5g are mixed in a container, water is added to make the volume 1L, stirred until the solute is dissolved, and the pH is adjusted to 7.0; 15g agar is added to the above nutrient gravy liquid medium to obtain a nutrient gravy agar medium.

[0014] Furthermore, in step S4, the mass ratio of the polygonatum odoratum extract, chitosan and corncob biochar is 10-15 g: 100-120 g: 10 kg. Furthermore, in step S4, the mass volume ratio of the microbial carrier and the mixed bacterial solution is 1 kg: 1 L.

[0015] The raw materials used in the present invention are all commercially available.

[0016] The method for using the microbial agent of the present invention is to apply it to the soil as a fertilizer before sowing, with an application amount of 4kg / mu.

[0017] The present invention is compounded with three functional strains to form a core microbial agent, wherein dinitrogen bradyrhizobium promotes early nodulation and multiple nodulation of peanuts, improves biological nitrogen fixation efficiency and improves soil nitrogen content, and also helps peanuts resist pests and diseases, significantly promoting the growth and yield increase of peanuts; Pseudomonas auriculata can produce antibiotic phenazine-1-carboxylic acid (PCA), which has a good inhibitory effect on peanut white rot pathogens, and in addition produces a large amount of plant growth hormone IAA and multiple effects such as phosphate solubilization, which have a significant growth-promoting effect on peanuts; the various biologically active substances secreted by Bacillus paralicheniformis can improve the activity of peanut root defense enzymes, improve crop resistance, and fundamentally improve the disease resistance of peanuts. In addition, various plant hormones such as auxin and cytokinin can be synthesized to promote peanut growth, so that the plant growth is more vigorous and the leaf color is dark green. After the three bacteria are mixed according to a specific ratio, the effect of improving peanut yield and quality is better than that of a single strain, and the composite use of the three bacteria is coordinated and has stronger adaptability to the complex environment of the rhizosphere.

[0018] The present invention uses a microbial carrier, which is composed of polygonatum odoratum extract, chitosan and corn cob biochar. Polygonatum odoratum extract can provide energy for microorganisms, and is also involved in the immune regulation process of plants, enhancing the defense capabilities of plants; chitosan can increase the water retention and aeration of the soil, promote the growth of beneficial microorganisms, and can also induce plants to produce resistance substances, inhibit pathogens and pests, promote root growth and activate the rhizosphere state; the pore structure inside the corn cob can effectively fix microorganisms, achieve effective load on microorganisms, and at the same time slowly release the effective ingredients secreted by microorganisms. The compounding of the three substances effectively improves the action time and stability of the composite microbial agent.

[0019] Beneficial Effects

[0020] The present invention selects three microbial strains that improve the yield and quality of peanuts, and the three strains all have a growth-promoting effect on peanuts. The three bacteria are compounded in a specific ratio, and a microbial carrier is added at the same time. The microbial agent composed effectively improves the agronomic traits of peanut plants, effectively increases peanut yield, and improves peanut quality. In addition, the microbial agent of the present invention reduces the application amount of chemical fertilizers and improves economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Figure 2 is the growth state diagram of different strains on LB medium; Note: A and D are Bradyrhizobium dinitrogenum, B is Bacillus paralicheniformis, and C is Pseudomonas ayuensis;

[0022] Figure 2 This is a diagram showing the inhibitory effect of the bacterial solution of Example 2 of the present invention on the pathogen of Sclerotium rolfsii;

[0023] Figure 3 This is a comparison diagram of peanut plants at the seedling stage in the conventional fertilization group and the group fertilized with Example 2 of the present invention;

[0024] Figure 4 This is a graph showing the effects of the bacterial agent and conventional fertilization group in Example 2 on the enzyme activity of the peanut root system. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with specific embodiments, but is not limited thereto.

[0026] Example 1

[0027] A composite microbial agent for improving peanut yield and quality, comprising dinitrogen bradyrhizobium, bacillus paralicheniformis and pseudomonas ayuensis.

[0028] The strain number of Bradyrhizobium dinitrogen is CGMCC No.1.15566, purchased from China General Microorganism Collection Center, and the original preservation date is December 30, 2015; the strain number of Bacillus paralicheniformis is CGMCC No.1.15832, purchased from China General Microorganism Collection Center, and the original preservation date is September 20, 2016; the strain number of Pseudomonas ayuensis is CGMCC No.1.16111, purchased from China General Microorganism Collection Center, and the original preservation date is March 29, 2017. The three strains used in the present invention can be purchased by querying in the strain catalog of China General Microorganism Collection Center, without repeated biological preservation.

[0029] A method for preparing a composite microbial agent for improving peanut yield and quality comprises the following steps:

[0030] S1: Thaw the dinitrogen bradyrhizobium and activate it in LB solid medium. Then pick a single colony of dinitrogen bradyrhizobium and inoculate it into liquid nitrogen-fixing medium. Cultivate at 28°C and 170r / min until OD 600 =0.6 to obtain seed solution, and inoculate 1% of the seed solution into 200 mL of liquid nitrogen fixation medium and culture at 28°C and 170 r / min. The bacterial liquid colony activity was detected by the dilution plate method, and the number of colonies reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a dinitrogen Bradyrhizobium bacterial solution;

[0031] S2: Bacillus paralicheniformis and Pseudomonas ayuensis were thawed and activated in nutrient broth agar medium, and single colonies of Bacillus paralicheniformis and Pseudomonas ayuensis were selected and inoculated into nutrient broth liquid medium, respectively, and cultured at 30°C and 200 r / min until OD 600 =0.6 to obtain seed solution, and then 1% of the seed solution was inoculated into 200mL nutrient gravy liquid culture medium and cultured at 30°C and 200r / min. The bacterial liquid colony activity was detected by the dilution plate method, and the number of colonies reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a bacterial solution of Bacillus paralicheniformis and Pseudomonas ayutans;

[0032] S3: mixing the three bacterial solutions in a volume ratio of 2:1:1 to obtain a mixed bacterial solution;

[0033] S4: Evenly mix the polygonatum odoratum extract and chitosan, then add 40-mesh corn cob biochar and stir evenly to obtain a microbial carrier; drop the mixed bacterial solution into the continuously stirred microbial carrier, and dry it after the dropwise addition is completed to obtain a microbial agent.

[0034] The mass ratio of the polygonatum odoratum extract, chitosan and corn cob biochar in step S4 is 10g:100g:10kg.

[0035] The mass volume ratio of the microbial carrier and the mixed bacterial solution in step S4 is 1 kg:1 L.

[0036] Verification of strain antagonism:

[0037] After the frozen Bradyrhizobium dinitrogenum, Bacillus paralicheniformis, and Pseudomonas ayutans were activated, they were streaked on LB plate medium and cultured at 28-30℃ for 3-5 days. Single colonies of the three bacteria were picked and streaked on one medium to prove that there was no mutual inhibition between the three strains. Figure 1 A and D are Bradyrhizobium dinitrogenum, B is Bacillus paralicheniformis, and C is Pseudomonas ayutans.

[0038] The growth status of the three bacterial strains was as follows Figure 1 As shown, there is no obvious inhibition zone between the three bacteria, indicating that there is no obvious inhibitory effect between them, and the bacterial solutions can be compounded.

[0039] Example 2

[0040] A composite microbial agent for improving peanut yield and quality, comprising dinitrogen bradyrhizobium, bacillus paralicheniformis and pseudomonas ayuensis.

[0041] The strain number of Bradyrhizobium dinitrogen is CGMCC No.1.15566, purchased from China General Microorganism Collection Center, and the original preservation date is December 30, 2015; the strain number of Bacillus paralicheniformis is CGMCC No.1.15832, purchased from China General Microorganism Collection Center, and the original preservation date is September 20, 2016; the strain number of Pseudomonas ayuensis is CGMCC No.1.16111, purchased from China General Microorganism Collection Center, and the original preservation date is March 29, 2017. The three strains used in the present invention can be purchased by querying in the strain catalog of China General Microorganism Collection Center, without repeated biological preservation.

[0042] A method for preparing a composite microbial agent for improving peanut yield and quality comprises the following steps:

[0043] S1: Thaw the dinitrogen bradyrhizobium and activate it in LB solid medium. Then pick a single colony of dinitrogen bradyrhizobium and inoculate it into liquid nitrogen-fixing medium. Cultivate at 28°C and 170r / min until OD 600=0.6 to obtain seed solution, and inoculate 1% of the seed solution into 200 mL of liquid nitrogen fixation medium and culture at 28°C and 170 r / min. The bacterial liquid colony activity was detected by the dilution plate method, and the number of colonies reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a dinitrogen Bradyrhizobium bacterial solution;

[0044] S2: Bacillus paralicheniformis and Pseudomonas ayuensis were thawed and activated in LB solid medium, and single colonies of Bacillus paralicheniformis and Pseudomonas ayuensis were selected and inoculated into LB liquid medium, respectively, and cultured at 30°C and 200 r / min until OD 600 =0.6 to obtain seed solution, and then 1% of the seed solution was inoculated into 200 mL LB liquid culture medium and cultured at 30°C and 200 r / min. The bacterial colony activity number was detected by the dilution plate method, and the number reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a bacterial solution of Bacillus paralicheniformis and Pseudomonas ayutans;

[0045] S3: mixing the three bacterial solutions in a volume ratio of 2:1:1 to obtain a mixed bacterial solution;

[0046] S4: Evenly mix the polygonatum odoratum extract and chitosan, then add 40-mesh corn cob biochar and stir evenly to obtain a microbial carrier; drop the mixed bacterial solution into the continuously stirred microbial carrier, and dry it after the dropwise addition is completed to obtain a microbial agent.

[0047] The mass ratio of the polygonatum odoratum extract, chitosan and corn cob biochar in step S4 is 15g:120g:10kg.

[0048] The mass volume ratio of the microbial carrier and the mixed bacterial solution in step S4 is 1 kg:1 L.

[0049] Comparative Example 1

[0050] The types and proportions of the functional bacteria were changed, that is, the volume ratio of the dinitrogen Bradyrhizobium solution, the paralicheniformis solution and the Pseudomonas ayutans solution was 1:1:1, and the remaining raw materials and preparation steps were the same as those in Example 2.

[0051] Comparative Example 2

[0052] The types and proportions of the functional bacteria were changed, that is, the volume ratio of the dinitrogen Bradyrhizobium solution, the paralicheniformis solution and the Pseudomonas ayutans solution was 1:2:1, and the remaining raw materials and preparation steps were the same as those in Example 2.

[0053] Comparative Example 3

[0054] The types and proportions of the functional bacteria were changed, that is, the volume ratio of the dinitrogen Bradyrhizobium solution, the paralicheniformis solution and the Pseudomonas ayutans solution was 1:1:2, and the remaining raw materials and preparation steps were the same as in Example 2.

[0055] Comparative Example 4

[0056] The types and proportions of the functional bacteria were changed, that is, only the dinitrogen Bradyrhizobium solution was used, and the remaining raw materials and preparation steps were the same as those in Example 2.

[0057] Comparative Example 5

[0058] The types and proportions of the functional bacteria were changed, that is, only the bacterial solution of Bacillus paralicheniformis was used, and the remaining raw materials and preparation steps were the same as those in Example 2.

[0059] Comparative Example 6

[0060] The types and proportions of the functional bacteria were changed, that is, only the Pseudomonas ayutans bacterial liquid was used, and the remaining raw materials and preparation steps were the same as those in Example 2.

[0061] Comparative Example 7

[0062] In this comparative example, except that the Polygonatum odoratum extract is not added to the microbial carrier, the other raw materials and preparation steps are the same as those in Example 2.

[0063] Test verification

[0064] Capacity determination of strains

[0065] Determination of nitrogen fixation ability: The test strain was inoculated into Asbhy nitrogen-free medium by the 4-point inoculation method, and each treatment was repeated 3 times. The strain was placed in a 30°C incubator and observed continuously to see whether a transparent circle was formed around the colony. The ratio between the diameter of the transparent circle (D) and the diameter of the colony (d) was determined.

[0066] Phosphorus solubilization capacity determination: The three bacterial suspensions obtained in steps S1 and S2 of Example 2 were pipetted into 100 ml of inorganic phosphorus liquid culture medium at 1% and repeated 3 times. The culture was cultured at 180-200 r / min and 30°C for 7 days. The pH value of the supernatant after centrifugation of the culture solution was measured every day, and the OD value of the supernatant was measured every day using the molybdenum antimony colorimetric method. 600 The soluble phosphorus content of the strain was determined according to the prepared phosphorus standard curve for 7 days.

[0067] Determination of the ability to produce IAA: The Salkowski colorimetric method was used to determine the ability of the strain to produce IAA. The darker the red color after the reaction, the stronger the ability of the strain to produce IAA. The absorbance was measured at 530 nm, and then the amount of IAA produced was calculated based on the standard curve of IAA.

[0068] Table 1 Identification of growth-promoting functions of various strains

[0069]

[0070] Test of the ability to inhibit pathogens: The plate confrontation method was used to detect the antagonism of the microbial culture of the present invention to peanut Sclerotium rolfsii. The method is as follows: an activated Sclerotium rolfsii cake with a diameter of 5 mm was inoculated in the center of a PDA plate, and the microbial culture of Example 2 of the present invention was inoculated at about 25 mm on the right side of the cake, and the mixture was repeated 3 times and cultured in the dark at 30°C. Figure 2 The inhibition effect diagram of the microbial bacterial liquid on white rot in Example 2 is shown in FIG. Figure 2 It can be seen that the microbial bacterial liquid of the present invention has a good inhibitory effect on white rot.

[0071] Field trials

[0072] Test location: Peanut planting area in Junan County, Linyi City, Shandong Province, with gravel soil, good permeability and flat terrain. Peanuts are planted all year round, with an organic matter content of 17.3g / kg in the 0-20cm tillage layer, 1.2g / kg in total nitrogen, 0.88g / kg in total phosphorus, 35.1g / kg in total potassium, 10.3mg / kg in available phosphorus and 165.3mg / kg in available potassium.

[0073] The experiment set up 9 treatments in total, including a conventional fertilization group (CK), and the microbial agents of Example 2 of the present invention and Comparative Examples 1-7 were applied as T0-T7:

[0074] CK: Conventional fertilization (urea, diammonium phosphate, potassium sulfate mixed with sulfur matrix in a ratio of 1:1:1, application rate is 600kg / hm 2 ); T0: 60% conventional fertilization + bacterial agent of Example 2; T1: 60% conventional fertilization + bacterial agent of Comparative Example 1; T2: 60% conventional fertilization + bacterial agent of Comparative Example 2; T3: 60% conventional fertilization + bacterial agent of Comparative Example 3; T4: 60% conventional fertilization + bacterial agent of Comparative Example 4; T5: 60% conventional fertilization + bacterial agent of Comparative Example 5; T6: 60% conventional fertilization + bacterial agent of Comparative Example 6; T7: 60% conventional fertilization + bacterial agent of Comparative Example 7.

[0075] Application of microbial agents: Conventional fertilization + the experimental groups of microbial agents obtained in Example 2 and Comparative Examples 1-7 were manually applied before sowing, with a rate of 1.5 times that of the experimental groups. 2 The dosage is 4 kg.

[0076] The plot area of ​​each treatment group was 15m 2 , 3 replicates, randomly arranged, with protection rows between each treatment group. The peanut variety for the test was Fenghua No. 1, 2 seeds were planted per hole, the sowing density was 10,000 holes per mu, the experiment was sown in early June 2023, and harvested at the end of September. Other field management was carried out according to general field management.

[0077] Index determination

[0078] Investigation on the main agronomic traits of peanuts: A 1m×1m plot was collected in the experimental area using the 5-point sampling method during the seedling and flowering stages to investigate the number of plant nodules; before harvest, 10 plants were selected from 5 holes for each treatment for indoor testing to investigate the main stem height, number of fruiting branches per plant, number of fruits per plant, and 100-fruit weight.

[0079] Yield survey: 1 point was selected in each test area, 3 repeated test plots were selected, a total of 3 points were selected, and 6.67m was selected at each point. 2 Harvest and measure yield: After the pods are fully dried, remove impurities, young fruits, rotten fruits, etc., and calculate the yield based on the quality of the plot.

[0080] Quality analysis: Seed kernel protein, fat, oleic acid and linoleic acid were determined using a Perton DA7250 near-infrared analyzer.

[0081] Determination of peanut root defense enzyme activity: The roots of the peanut plants were rinsed with tap water, soil particles were removed, and the moisture on the root surface was dried with paper. All the fibrous roots were collected and placed in a ziplock bag, frozen in liquid nitrogen, and then stored at -80°C for the determination of plant defense enzyme activity. Phenylalanine ammonia lyase, polyphenol oxidase and peroxidase were all determined using the corresponding plant enzyme activity kits.

[0082] Table 1 Nodule number performance

[0083]

[0084] It can be seen from the data in Table 1 that, during the seedling and flowering stages of peanuts, compared with the CK group that applied conventional fertilizers, the peanuts in the T0 group that applied the composite microbial agent of Example 2 of the present invention nodulated earlier, and the number of nodules increased significantly, with the average number of nodules reaching 196.2 per plant during the flowering stage. This shows that the application of the microbial agent of the present invention can promote early nodulation of peanuts and increase the number of nodules. In addition, field observations during the seedling stage showed that the plants in the group treated with the microbial agent of the present invention grew more vigorously than the CK group, and the leaves were dark green. The control results are shown in Table 1. Figure 3 .

[0085] Table 2 Agronomic traits and yield of peanut plants

[0086]

[0087] As shown in Table 2, the application of the microbial agent of the present invention has different degrees of influence on the main agronomic traits of peanuts. Compared with the CK group, the plants became shorter after the application of the microbial agent, and the number of fruits per plant, the number of full fruits per plant, the weight of 100 fruits and the yield were significantly improved. The number of fruit branches per plant increased by 30% compared with the CK group, the number of full fruits per plant increased by 22.1% compared with the CK group, the weight of 100 fruits increased by 9.4% compared with the CK group, and the yield increased by 11.8% compared with the control group, indicating that the application of the microbial agent of the present invention reduces the use of conventional fertilizers, and the agronomic traits and yield of peanuts are significantly improved. In the T1-T6 group, which changed the composition of the agent, the synergistic effect between the three strains was broken, and the agronomic traits and yield of peanuts were reduced; the T7 group, which changed the microbial carrier component, also led to a decrease in peanut yield. Therefore, the compounding of the three strains of the present invention and the composition of the microbial carrier are key technical means, and the effect is weak if one is missing.

[0088] Table 3 Peanut quality

[0089] Group Protein content (%) Fat(%) Oleic acid content (%) Linoleic acid content (%) CK 26.4 48.2 51.5 32.6 T0 33.4 52.1 58.3 27.6 T1 32.2 51.3 54.1 29.1 T2 32.0 51.6 53.7 30.3 T3 31.9 51.7 53.0 30.5 T4 30.5 48.9 52.2 30.9 T5 29.9 50.8 51.9 31.2 T6 28.1 51.1 51.1 31.7 T7 32.7 51.9 55.2 28.8

[0090] The effects of different treatments on peanut quality are shown in Table 3. Compared with the CK group, the protein content, fat content, and oleic acid content of the T0 test group after being treated with the microbial agent of Example 2 of the present invention were all improved. In addition, compared with the CK group, the linoleic acid content after being treated with the microbial agent of the present invention was reduced, and the stability of the peanut oil after being squeezed into peanut oil can be improved. This shows that the application of the microbial agent of the present invention can not only improve the quality of peanuts, but also lay a foundation for the stability of the peanut oil squeezed.

[0091] In addition, Figure 4 As shown, the bacterial agent of the present invention can increase the activities of multiple enzymes in the roots of peanuts, such as phenylalanine ammonia lyase, polyphenol oxidase, peroxidase and the like. The increase in enzyme activity can enhance the resistance of peanut plants to diseases and insect pests, reduce the incidence of diseases, and improve the resistance of peanuts.

[0092] It should be noted that the above embodiments are only partial embodiments of the preferred methods of implementing the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

Claims

1. A composite microbial agent for improving peanut yield and quality, characterized in that: The composite microorganisms consist of Bradyrhizobium diazoefficiens, Bacillus paralicheniformis and Pseudomonas plecoglossicida.

2. The composite microbial agent for improving peanut yield and quality according to claim 1, characterized in that: The dinitrogen Bradyrhizobium strain is numbered CGMCC No.1.15566 and was purchased from the China General Microorganism Collection Center; the paralicheniformis strain is numbered CGMCC No.1.15832 and was purchased from the China General Microorganism Collection Center; the Pseudomonas ayuensis strain is numbered CGMCC No.1.16111 and was purchased from the China General Microorganism Collection Center.

3. A method for preparing the composite microbial agent for improving peanut yield and quality according to any one of claims 1-2, characterized in that: The following steps are involved: S1: Thaw the dinitrogen bradyrhizobium and activate it in LB solid medium. Then pick a single colony of dinitrogen bradyrhizobium and inoculate it into liquid nitrogen-fixing medium. Cultivate at 28°C and 170r / min until OD 600 =0.6 to obtain seed solution, and inoculate 1% of the seed solution into 200 mL of liquid nitrogen fixation medium and culture at 28°C and 170 r / min. The bacterial liquid colony activity was detected by the dilution plate method, and the number of colonies reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a dinitrogen Bradyrhizobium bacterial solution; S2: Bacillus paralicheniformis and Pseudomonas ayuensis were thawed and activated in nutrient broth agar medium, and single colonies of Bacillus paralicheniformis and Pseudomonas ayuensis were selected and inoculated into nutrient broth liquid medium, respectively, and cultured at 30°C and 200 r / min until OD 600 =0.6 to obtain seed solution, and then 1% of the seed solution was inoculated into 200mL nutrient gravy liquid culture medium and cultured at 30°C and 200r / min. The bacterial liquid colony activity was detected by the dilution plate method, and the number of colonies reached 1×10 7 cfu·mL -1 After the culture was terminated, the culture was washed three times with a sterile PBS buffer solution and then resuspended to obtain a bacterial solution of Bacillus paralicheniformis and Pseudomonas ayutans; S3: mixing the three bacterial solutions in a volume ratio of 2:1:1 to obtain a mixed bacterial solution; S4: Evenly mix the polygonatum odoratum extract and chitosan, then add 40-mesh corn cob biochar and stir evenly to obtain a microbial carrier; drop the mixed bacterial solution into the continuously stirred microbial carrier, and dry it after the dropwise addition is completed to obtain a microbial agent.

4. The method for preparing the composite microbial agent for improving peanut yield and quality according to claim 3, characterized in that: In the step S4, the mass ratio of the polygonatum odoratum extract, chitosan and corn cob biochar is 10-15 g: 100-120 g: 10 kg.

5. The method for preparing the composite microbial agent for improving peanut yield and quality according to claim 3, characterized in that: The mass volume ratio of the microbial carrier and the mixed bacterial solution in step S4 is 1 kg:1 L.

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