Yield-increasing compound microbial agent for wheat and preparation method of yield-increasing compound microbial agent

Abstract

The invention discloses a yield-increasing compound microbial agent for wheat and a preparation method of the yield-increasing compound microbial agent, and belongs to the technical field of microorganisms. The compound microbial agent comprises a microbial agent and a carrier, wherein the microbial agent comprises bacillus velezensis, arthrobacter bainite and streptomyces microflavus; the carrier is a rare earth modified diatomite composite material; the mass ratio of the microbial agent to the carrier is 1: (5-8). The three bacteria have a synergistic effect, so that the disease-resistant and growth-promoting effects of wheat are realized, and the effects of increasing the income of wheat field planting and improving the quality are obvious. The rare earth modified diatomite compound is used as a carrier, and the special microporous structure of the rare earth modified diatomite compound enables the prepared microbial agent to have good stability and slow-release effect, so that the microbial agent disclosed by the invention plays a role lastingly and stably, has strong adaptability in an actual soil rhizosphere complex environment, and has a stable and remarkable wheat yield-increasing physique effect; the method has wide economic benefits and social benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a composite microbial agent for increasing wheat yield and a preparation method thereof. Background Art

[0002] Wheat is the most widely distributed, largest planted area, and highest commodity rate food crop in the world. The wheat planting area accounts for about 22% of the total planted area of ​​food crops in my country, and the output accounts for more than 20% of the total food output. In particular, the output of winter wheat accounts for more than 90% of the total wheat output in the country. It is my country's main food crop and an important commodity grain and strategic reserve grain variety, and plays an important role in food production, circulation, and consumption. With the continuous improvement of people's living standards, people have higher requirements for the quality of wheat.

[0003] Wheat cultivation in my country is mainly winter wheat, which has the characteristics of a long growth cycle and high soil requirements. Therefore, in the process of wheat cultivation, in order to pursue yield, large amounts of fertilizers and pesticides are used continuously in batches. Long-term and large-scale use of fertilizers and pesticides will cause changes in the physical and chemical properties of the soil, leading to soil nutrient imbalance, aggravating soil acidification and salinization, increasing soil heavy metals and toxic elements, destroying soil structure, leading to a decrease in the diversity and number of soil microorganisms, and affecting the biodiversity of the soil ecosystem. In addition, the long-term application of fertilizers will indirectly bring about a series of problems such as ecological security and food safety, causing a large amount of social and economic losses and serious environmental pollution.

[0004] Plants interact with various microorganisms during their growth, mainly including rhizosphere microorganisms, phyllosphere microorganisms and plant endophytes. These microorganisms can promote plant growth directly or indirectly by fixing nitrogen, solubilizing phosphorus, secreting auxins, increasing plant resistance, etc. In agricultural production, exogenous inoculation of such beneficial microorganisms can not only promote plant growth and increase crop yields, but also its environmental friendliness and sustainability of effects are highly respected in contemporary agriculture, which pays more and more attention to the ecological environment.

[0005] However, the effect of single microbial agents is not ideal at present. Some composite microbial agents have poor stability and durability due to poor synergistic ability of the selected strains or poor carrier stability. They have poor adaptability to wheat, especially for winter wheat with a long growth cycle. Therefore, how to develop a composite microbial agent for wheat with many beneficial functions such as increasing yield and resisting diseases, and synergistic effects of various strains is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a composite microbial agent for increasing wheat yield, which adopts the synergistic effect of three strains of Bacillus velez, Arthrobacter bayenii and Streptomyces tenuifolius to promote the growth and development of wheat, with significant effects of increasing yield and improving quality, and has good market application and promotion value.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention is: A composite microbial agent for increasing wheat yield comprises a microbial agent and a carrier, wherein the microbial agent comprises Bacillus velez, Arthrobacter bayleyi and Streptomyces tenuiflavos; the carrier is a rare earth modified diatomaceous earth composite; and the mass ratio of the microbial agent to the carrier is 1:5-8.

[0008] Preferably, the rare earth modified diatomaceous earth composite is prepared by the following method: A: Mix diatomite, halloysite and starch in proportion, wet-mill for 1 hour with anhydrous ethanol as solvent, and then dry and sieve through a 200-mesh sieve to obtain a premix; B: Add an appropriate amount of 4wt% polyvinyl alcohol to the premix, grind for 10-20min, add it to a tube furnace and calcine at high temperature for 2h, and then grind it to obtain a diatomite-based porous material; C: Prepare a 0.2 mol / L cerium nitrate solution, immerse the diatomite-based porous material in it, let it stand for 24 hours, filter it, dry it in an oven, transfer it to a muffle furnace and calcine it for 3 hours, grind it into powder, and obtain a rare earth modified diatomite composite.

[0009] Preferably, the mass ratio of diatomite, halloysite and starch is 2:1:10.

[0010] Preferably, the ratio of the premix to polyvinyl alcohol is 10 g:1 ml.

[0011] Preferably, the high temperature calcination temperature in step B is 1000°C.

[0012] Preferably, the usage ratio of the cerium nitrate solution to the diatomaceous earth-based porous material is 30 ml:1 g; and the muffle furnace calcination temperature is 300°C.

[0013] Preferably, the strain number of the Bacillus velez is CGMCC No.1.12669, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation date is September 10, 2013; the strain number of the Arthrobacter bayenii is CGMCC No.1.10873, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation date is April 1, 2011; the strain number of the Streptomyces tenuifolius is CGMCC No.4.6163, and the preservation date is September 3, 2008. The Bacillus velezii, Arthrobacter bayenii, and Streptomyces tenuifolius used in the present invention can all be purchased through the strain catalog of the collection center without the need for additional preservation.

[0014] Preferably, the preparation method of the microbial agent is as follows: Bacillus velez, Arthrobacter bayleyi, and Streptomyces tenuifolius are activated in YMA solid culture medium respectively, and then all are inoculated into a test tube of TY liquid culture medium, and cultured at 28°C and 200r / min until OD 600 ≈2.0, inoculate 3% of the seed liquid into 200 mL of fermentation liquid medium, ferment and culture at 28°C and 200r / min for 12 h, stop the fermentation to obtain three fermentation broths, and then mix them in a volume ratio of 1:1:1 to obtain the microbial agent.

[0015] The YMA solid culture medium is composed of: 10 g / L glucose, 1 g / L yeast extract, 0.5 g / L dipotassium hydrogen phosphate, 0.2 g / L magnesium sulfate, 0.1 g / L sodium chloride, 1 g / L calcium carbonate, and 15 g / L agar powder; pH 6.8±0.2, and sterilization conditions: 121° C., 15 min.

[0016] The composition of the TY liquid culture medium is: tryptone 20 g / L, yeast extract 5.0 g / L, FeCl3·6H2O 7.0 mg / L, MnCl3·4H2O 1.0 mg / L, MgSO4·7H2O 15.0 mg / L, and distilled water 1.0 L; pH 7.1±0.2, sterilization conditions: 121°C, 15 min.

[0017] Preferably, the fermentation liquid culture medium is composed of: 10 g glucose, 10 g yeast powder, 1 g sodium chloride, 0.1 g MgSO4·7H2O, 0.1 g K2HPO4, 2 g (NH4)2SO4, 1000 ml distilled water, natural pH, sterilization conditions: 121°C, 30 min.

[0018] The present invention also provides a method for preparing the above-mentioned composite microbial agent for increasing wheat yield, which comprises the following steps: (1) Preparing a rare earth modified diatomite composite material according to the above method; (2) preparing a microbial agent according to the above method; (3) The rare earth modified diatomaceous earth composite material obtained in step (1) is uniformly mixed with the microbial agent according to a mass ratio, and the final product is obtained after natural drying.

[0019] The designed dosage of the composite microbial agent for increasing wheat yield of the present invention is 20kg / mu.

[0020] Unless otherwise specified, the raw materials used in the present invention are commercially available.

[0021] The Bacillus Velez in the microbial agent of the present invention can produce secondary metabolites that resist pests and diseases, can well inhibit the occurrence of various fungal and bacterial diseases such as powdery mildew, root rot, leaf rust, etc. that wheat is prone to, can secrete plant hormones that promote plant growth and has the ability to produce iron carriers; while Streptomyces pyogenes can secrete a variety of metabolites that inhibit soil-borne diseases, it can also transform nitrogen, phosphorus, and potassium in the soil, improve soil fertility, and reduce the amount of chemical fertilizers; and Arthrobacter berberis can produce a large amount of microbial extracellular active oxygen under the stimulation of plant-derived iron carriers and suitable carbon source concentrations, these active oxygen can effectively degrade pesticide residues in the soil, heavy metals and other heavy soil pollutants, and can also participate in other beneficial microbial metabolic reactions, participate in the generation and transfer of energy, promote beneficial microorganisms to produce more beneficial metabolites, better improve soil properties, improve soil fertility, and promote crop growth. The three strains interact with each other, complement each other, and jointly achieve the effect of improving wheat yield and quality.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The microbial agent of the present invention produces a good synergistic effect through the combination of Bacillus velezensis, Arthrobacter bayenii and Streptomyces tenuifolius, enriches the content of soil microbial bacteria, increases soil microbial diversity, increases wheat yield and quality, improves soil physical and chemical properties, and is safe and environmentally friendly.

[0023] (2) The present invention is designed to use a rare earth modified diatomaceous earth composite as a microbial carrier. The carrier structure has a large specific surface area and rich pore structure, which is conducive to the attachment and adsorption of microorganisms. The carrier is a porous diatomaceous earth-based ceramic material. While protecting the activity of the microbial flora, it can also provide rich nutrition and growth conditions for the microorganisms, so that the microorganisms can multiply rapidly in large quantities on the carrier and be continuously released into the soil, with good stability and durability. At the same time, the carrier also contains an appropriate amount of rare earth cerium element, which can improve the metabolic activity of microorganisms, enhance the adaptability of microorganisms in complex environments, increase the ability of soil microorganisms to degrade pollutants, promote the growth and development of wheat, enhance its disease resistance, and significantly improve wheat yield and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The SEM images of the carrier used for the composite microbial agent of the present invention at different resolutions, wherein a is a low-resolution SEM image and b is a high-resolution SEM image; Figure 2 This is a graph showing the test results of urease activity in soil after using the composite microbial agent prepared in the examples and comparative examples of the present invention; Figure 3 This is a test result diagram of alkaline phosphatase activity in soil after using the composite microbial agent prepared in the examples and comparative examples of the present invention; Figure 4 This is a graph showing the effects of different mass ratios of the microbial agent and the carrier in the composite microbial agent prepared in the present invention on wheat planting yield. 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 A composite microbial agent for increasing wheat yield comprises a microbial agent and a carrier, wherein the microbial agent comprises Bacillus velez, Arthrobacter baylei and Streptomyces tenuiflavos; the carrier is a rare earth modified diatomaceous earth composite; and the mass ratio of the microbial agent to the carrier is 1:5.

[0027] The method for preparing the composite microbial agent for increasing wheat yield comprises the following steps: (1) Preparation of rare earth modified diatomite composite materials: A: Diatomaceous earth, halloysite and starch are uniformly mixed in proportion, wet-milled for 1 hour using anhydrous ethanol as a solvent, and then dried and sieved through a 200-mesh sieve to obtain a premix; the mass ratio of the diatomaceous earth, halloysite and starch is 2:1:10.

[0028] B: Add an appropriate amount of 4wt% polyvinyl alcohol to the premix, grind for 10-20min, add it to a tube furnace and calcine it at 1000°C for 2h, and obtain a diatomaceous earth-based porous material after crushing and grinding; the dosage ratio of the premix to polyvinyl alcohol is 10g:1ml.

[0029] C: Prepare a 0.2 mol / L cerium nitrate solution, immerse the diatomite-based porous material in it at a material-liquid ratio of 30 ml: 1 g, let it stand for 24 hours, filter it, dry it in an oven, transfer it to a muffle furnace and calcine it at 300°C for 3 hours, grind it into powder, and obtain a rare earth modified diatomite composite.

[0030] (2) Preparation of microbial agents: Bacillus velezensis, Arthrobacter bayleyi, and Streptomyces tenuiflavos were activated in YMA solid medium, and then all were inoculated into test tubes of TY liquid medium and cultured at 28°C and 200 r / min until OD 600 ≈2.0, inoculate 3% of the seed liquid into 200 mL of fermentation liquid medium, ferment and culture at 28°C and 200 r / min for 12 h, stop the fermentation to obtain three fermentation broths, and then mix them in a volume ratio of 1:1:1 to obtain the microbial agent.

[0031] The YMA solid culture medium is composed of: 10 g / L glucose, 1 g / L yeast extract, 0.5 g / L dipotassium hydrogen phosphate, 0.2 g / L magnesium sulfate, 0.1 g / L sodium chloride, 1 g / L calcium carbonate, and 15 g / L agar powder; pH 6.8±0.2, and sterilization conditions: 121° C., 15 min.

[0032] The composition of the TY liquid culture medium is: tryptone 20 g / L, yeast extract 5.0 g / L, FeCl3·6H2O 7.0 mg / L, MnCl3·4H2O 1.0 mg / L, MgSO4·7H2O 15.0 mg / L, and distilled water 1.0 L; pH 7.1±0.2, sterilization conditions: 121°C, 15 min.

[0033] The fermentation liquid culture medium is composed of: 10 g glucose, 10 g yeast powder, 1 g sodium chloride, 0.1 g MgSO4·7H2O, 0.1 g K2HPO4, 2 g (NH4)2SO4, 1000 ml distilled water, natural pH, sterilization conditions: 121°C, 30 min.

[0034] (3) The rare earth modified diatomaceous earth composite material obtained in step (1) is uniformly mixed with the microbial agent according to a mass ratio, and the final product is obtained after natural drying.

[0035] The Bacillus velezensis strain is numbered CGMCC No.1.12669, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation date is September 10, 2013; the Arthrobacter bayenii strain is numbered CGMCC No.1.10873, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation time is April 1, 2011; the Streptomyces tenuifolius strain is numbered CGMCC No.4.6163, and the preservation time is September 3, 2008.

[0036] Example 2 A composite microbial agent for increasing wheat yield comprises a microbial agent and a carrier, wherein the microbial agent comprises Bacillus velez, Arthrobacter baylei and Streptomyces tenuiflavos; the carrier is a rare earth modified diatomaceous earth composite; and the mass ratio of the microbial agent to the carrier is 1:6.

[0037] The method for preparing the composite microbial agent for increasing wheat yield comprises the following steps: (1) Preparation of rare earth modified diatomite composite materials: A: Diatomaceous earth, halloysite and starch are uniformly mixed in proportion, wet-milled for 1 hour using anhydrous ethanol as a solvent, and then dried and sieved through a 200-mesh sieve to obtain a premix; the mass ratio of the diatomaceous earth, halloysite and starch is 2:1:10.

[0038] B: Add an appropriate amount of 4wt% polyvinyl alcohol to the premix, grind for 10-20min, add it to a tube furnace and calcine it at 1000°C for 2h, and obtain a diatomaceous earth-based porous material after crushing and grinding; the dosage ratio of the premix to polyvinyl alcohol is 10g:1ml.

[0039] C: Prepare a 0.2 mol / L cerium nitrate solution, immerse the diatomite-based porous material in it at a material-liquid ratio of 30 ml: 1 g, let it stand for 24 hours, filter it, dry it in an oven, transfer it to a muffle furnace and calcine it at 300°C for 3 hours, grind it into powder, and obtain a rare earth modified diatomite composite.

[0040] (3) Preparation of microbial agents: Bacillus velezensis, Arthrobacter bayleyi, and Streptomyces tenuiflavos were activated in YMA solid medium, and then all were inoculated into test tubes of TY liquid medium and cultured at 28°C and 200 r / min until OD 600 ≈2.0, inoculate 3% of the seed liquid into 200 mL of fermentation liquid medium, ferment and culture at 28°C and 200 r / min for 12 h, stop the fermentation to obtain three fermentation broths, and then mix them in a volume ratio of 1:1:1 to obtain the microbial agent.

[0041] The YMA solid culture medium is composed of: 10 g / L glucose, 1 g / L yeast extract, 0.5 g / L dipotassium hydrogen phosphate, 0.2 g / L magnesium sulfate, 0.1 g / L sodium chloride, 1 g / L calcium carbonate, and 15 g / L agar powder; pH 6.8±0.2, and sterilization conditions: 121° C., 15 min.

[0042] The composition of the TY liquid culture medium is: tryptone 20 g / L, yeast extract 5.0 g / L, FeCl3·6H2O 7.0 mg / L, MnCl3·4H2O 1.0 mg / L, MgSO4·7H2O 15.0 mg / L, and distilled water 1.0 L; pH 7.1±0.2, sterilization conditions: 121°C, 15 min.

[0043] The fermentation liquid culture medium is composed of: 10 g glucose, 10 g yeast powder, 1 g sodium chloride, 0.1 g MgSO4·7H2O, 0.1 g K2HPO4, 2 g (NH4)2SO4, 1000 ml distilled water, natural pH, sterilization conditions: 121°C, 30 min.

[0044] (3) The rare earth modified diatomaceous earth composite material obtained in step (1) is uniformly mixed with the microbial agent according to a mass ratio, and the final product is obtained after natural drying.

[0045] The Bacillus velezensis strain is numbered CGMCC No.1.12669, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation date is September 10, 2013; the Arthrobacter bayenii strain is numbered CGMCC No.1.10873, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation time is April 1, 2011; the Streptomyces tenuifolius strain is numbered CGMCC No.4.6163, and the preservation time is September 3, 2008.

[0046] Example 3 A composite microbial agent for increasing wheat yield comprises a microbial agent and a carrier, wherein the microbial agent comprises Bacillus velez, Arthrobacter baylei and Streptomyces tenuiflavos; the carrier is a rare earth modified diatomaceous earth composite; and the mass ratio of the microbial agent to the carrier is 1:8.

[0047] The method for preparing the composite microbial agent for increasing wheat yield comprises the following steps: (1) Preparation of rare earth modified diatomite composite materials: A: Diatomaceous earth, halloysite and starch are uniformly mixed in proportion, wet-milled for 1 hour using anhydrous ethanol as a solvent, and then dried and sieved through a 200-mesh sieve to obtain a premix; the mass ratio of the diatomaceous earth, halloysite and starch is 2:1:10.

[0048] B: Add an appropriate amount of 4wt% polyvinyl alcohol to the premix, grind for 10-20min, add it to a tube furnace and calcine it at 1000°C for 2h, and obtain a diatomaceous earth-based porous material after crushing and grinding; the dosage ratio of the premix to polyvinyl alcohol is 10g:1ml.

[0049] C: Prepare a 0.2 mol / L cerium nitrate solution, immerse the diatomite-based porous material in it at a material-liquid ratio of 30 ml: 1 g, let it stand for 24 hours, filter it, dry it in an oven, transfer it to a muffle furnace and calcine it at 300°C for 3 hours, grind it into powder, and obtain a rare earth modified diatomite composite.

[0050] (4) Preparation of microbial agents: Bacillus velezensis, Arthrobacter bayleyi, and Streptomyces tenuiflavos were activated in YMA solid medium, and then all were inoculated into test tubes of TY liquid medium and cultured at 28°C and 200 r / min until OD 600 ≈2.0, inoculate 3% of the seed liquid into 200 mL of fermentation liquid medium, ferment and culture at 28°C and 200 r / min for 12 h, stop the fermentation to obtain three fermentation broths, and then mix them in a volume ratio of 1:1:1 to obtain the microbial agent.

[0051] The YMA solid culture medium is composed of: 10 g / L glucose, 1 g / L yeast extract, 0.5 g / L dipotassium hydrogen phosphate, 0.2 g / L magnesium sulfate, 0.1 g / L sodium chloride, 1 g / L calcium carbonate, and 15 g / L agar powder; pH 6.8±0.2, and sterilization conditions: 121° C., 15 min.

[0052] The composition of the TY liquid culture medium is: tryptone 20 g / L, yeast extract 5.0 g / L, FeCl3·6H2O 7.0 mg / L, MnCl3·4H2O 1.0 mg / L, MgSO4·7H2O 15.0 mg / L, and distilled water 1.0 L; pH 7.1±0.2, sterilization conditions: 121°C, 15 min.

[0053] The fermentation liquid culture medium is composed of: 10 g glucose, 10 g yeast powder, 1 g sodium chloride, 0.1 g MgSO4·7H2O, 0.1 g K2HPO4, 2 g (NH4)2SO4, 1000 ml distilled water, natural pH, sterilization conditions: 121°C, 30 min.

[0054] (3) The rare earth modified diatomaceous earth composite material obtained in step (1) is uniformly mixed with the microbial agent according to a mass ratio, and the final product is obtained after natural drying.

[0055] The Bacillus velezensis strain is numbered CGMCC No.1.12669, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation date is September 10, 2013; the Arthrobacter bayenii strain is numbered CGMCC No.1.10873, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation time is April 1, 2011; the Streptomyces tenuifolius strain is numbered CGMCC No.4.6163, and the preservation time is September 3, 2008.

[0056] Comparative Example A comparative test group was set up, and the volume ratio of Bacillus velez (A1), Arthrobacter berberis (A2), and Streptomyces tenuifolius (A3) in the microbial agent was changed, and the rest was the same as in Example 3. The specific groups are shown in the following table: Table 1 Comparative Example Settings

[0057] Field planting trial Test site: A wheat field in Sunjialing Village, Tianliu Town, Shouguang City, Shandong Province was selected as the test site. Basic physical and chemical properties of 0-20cm soil: organic matter 23.56 g / kg, total nitrogen 3.59 g / kg, alkaline nitrogen 81.12 mg / kg, available phosphorus 52.33 mg / kg, and available potassium 133.25 mg / kg. The previous crop in the test site was corn.

[0058] Wheat variety tested: Jimai 22.

[0059] Experimental design: There are 6 treatments in total, each treatment is repeated 3 times to take the average value, and the area of ​​each plot is 1 mu.

[0060] Experimental method: Treatment 1 is to apply the microbial agent of Example 3, treatments 2-10 are respectively to apply the microbial agents prepared by comparative examples 2-9, and treatment 11 is a blank control group without any microbial agent treatment; before sowing, each treatment group uses conventional compound fertilizer (N: P2O5: K2O = 18: 15: 12) as basal fertilizer and turns it into the soil at a rate of 50 kg / mu, and then at the seedling stage, the microbial agents prepared by Example 4 and comparative examples 2-9 are furrowed into the soil at a rate of 20 kg / mu, and the blank control group is not topdressed with any microbial agent; the remaining management measures of each treatment group are conventional wheat field management measures.

[0061] Survey content and measurement method: During the critical period of wheat growth, three measurement points were randomly selected in each treatment and the field measurement was carried out at 1 m 2 The average value of the three test points is the test result of the treatment; the total number of plants per mu = 1 m 2The number of plants per mu was calculated by multiplying the number of plants by 667. The wheat growth of different fertilization treatment groups was counted at the heading and flowering stage. The specific results are shown in Table 1.

[0062] Table 1 Wheat development in different treatment groups at heading and flowering stage

[0063] As can be seen from Table 1 above, after using the composite microbial agent prepared by the present invention, the number of wheat plants per mu, the number of tillers per plant and the plant height are significantly higher than those of the blank control, and higher than those of other comparative examples. This shows that the composite microbial agent for wheat of the present invention can have a good growth-promoting effect on wheat.

[0064] In order to test the control effect of the composite microbial agent for wheat prepared by the present invention on common powdery mildew and leaf rust diseases of wheat, an investigation was conducted at the full heading stage of wheat growth, referring to the "Wheat Powdery Mildew Forecasting Survey Specification" (NY / T 613-2002) and the "Wheat Leaf Rust Forecasting Survey Specification" (NY / T617-2002). Three points were investigated for each treatment, and 100 plants were randomly selected from each point to investigate the disease conditions of all leaves. The specific results are shown in Table 2.

[0065] Symptom identification: There are filamentous white mold spots on the diseased areas of wheat leaves infected with powdery mildew. As the wheat grows, the mold layer covering the surface gradually thickens and becomes fluffy, and the color gradually changes from white to gray. Wheat leaves or stems infected with leaf rust produce multiple layers of bright yellow summer spores arranged in a wheel shape. When the disease first occurs on the leaves of mature plants, the summer spores are small, long, bright yellow, and oval in shape, parallel to the leaf veins, and arranged in rows. Later, the epidermis breaks and rust-colored powder appears. When you touch the diseased spots with your hands, your hands will be sticky with rust powder.

[0066] Grading standard: It is set according to the severity of diseased leaves, that is, the ratio of the leaf area covered by the mycelium layer on the diseased leaves to the total leaf area. There are 8 levels in total, represented by 1%, 5%, 10%, 20%, 40%, 60%, 80% and 100% respectively; for the disease between the levels, the approximate value is taken; if the disease has occurred but the severity is less than 1%, it is recorded as 1%.

[0067] Calculation of disease index: disease index = 100×∑(number of diseased leaves at each level×representative value at each level) / (total number of leaves surveyed×highest representative value).

[0068] Table 2 Survey results of wheat powdery mildew and leaf rust in different treatment groups

[0069] It can be seen from Table 2 above that the composite microbial fertilizer for wheat prepared in the embodiment of the present invention has significantly lower diseased plant rate, diseased leaf rate and disease index for common powdery mildew and leaf rust of wheat than the blank control group, which indicates that the prepared composite microbial agent can significantly improve the disease resistance of wheat.

[0070] Multiple indicators can be used to measure the quality of wheat. This experiment uses four indicators to measure the quality of wheat, including grain bulk density, protein content, wet gluten content and yield. The specific test method is as follows: the wheat ears are harvested by the five-point sampling method, repeated 3 times, finely threshed and air-dried, and the thousand-grain weight is measured. To ensure the uniformity and hydrolysis effect of the sample, the harvested wheat grains are crushed and passed through an 80-mesh sieve. The protein content of wheat is measured by the Kjeldahl method in GB5009.5-2016, and the wet gluten content is determined by GB / T 5506.1-2008. Yield statistics are calculated at the harvest time. The total weight of all products in each treatment group. See Table 3 for details.

[0071] Table 3 Wheat yield and quality

[0072] The present invention also tests the contents of total cadmium, total nickel, total lead and total chromium in wheat in different treatments. 50 grains of wheat are randomly selected as test samples in each treatment group. After washing and drying, they are crushed and sieved, and put into centrifuge tubes for later use. The heavy metal content in the samples of each treatment group is determined by atomic absorption spectrometry. The results are shown in Table 4.

[0073] Table 4 Detection results of heavy metal content in wheat with different treatments

[0074] According to the results of Tables 3-4 above, it can be seen that the yield and quality of the product wheat after the composite microbial agent prepared in Example 3 of the present invention is significantly improved, and the heavy metal content is significantly lower than that of the blank control group. This is because the three dominant strains used in the present invention can work synergistically to increase the microbial activity in the soil, and the porous diatomaceous earth-based ceramic material of the prepared carrier can protect the activity of the microbial flora from being destroyed, and can also provide rich nutrition and growth conditions for microorganisms, so that the microorganisms can reproduce rapidly on the carrier and continuously release into the soil, with good stability and durability; in addition, the carrier also contains rare earth cerium, which can improve the activity of microorganisms, increase the degradation ability of soil microorganisms to harmful pollutants such as pesticide residues and soil heavy metals, promote the growth and development of wheat, enhance its disease resistance, and significantly improve wheat yield and quality.

[0075] Surface soil (0-20 cm) samples were collected after wheat harvest, and soil samples were collected from each treatment group using the S-shaped sampling method. When collecting soil, the soil drill was drilled to a depth of 20 cm at one time. Three replicates were collected from each treatment group, and the three replicates of the same treatment group were mixed into one sample. Visible debris such as gravel and plant roots were removed and brought back to the laboratory for determination of soil enzyme activity. The soil urease activity was determined using the phenol-sodium hypochlorite colorimetric method; the alkaline phosphatase activity was determined using the kit method. The results are shown in Figure 2-3 .

[0076] from Figure 2-3 It can be seen from the results that after the composite microbial agent of the embodiment of the present invention is used, the soil urease activity and alkaline phosphatase activity are higher than those of the comparative examples 1-9 and the blank control group. Soil enzymes are produced by the interaction of soil microorganisms. They participate in material circulation and energy flow and are an important indicator for evaluating soil fertility and soil microbial activity. Enzyme activity is closely related to plants, microorganisms, and soil nutrients. The carrier in the composite microbial agent of the present invention is a rare earth modified diatomaceous earth composite, which improves the activity and long-term stability of microorganisms, and increases the degradation ability of soil microorganisms to harmful pollutants such as pesticide residues and soil heavy metals, while the three composite strains can act synergistically to maximize the enrichment of the types and quantity of microbial flora in the soil, and the soil enzyme activity is also correspondingly improved.

[0077] In order to further verify the effect of the carrier dosage on the use effect of the composite microbial agent for wheat in the present invention, the present invention further studies the effect of the composite microbial agent for wheat prepared by compounding the microbial agent and the carrier in different proportions in the formula composition on the wheat planting yield.

[0078] Experimental site and test varieties: Another farmland in Sunjialing Village, Tianliu Town, Shouguang City, Shandong Province was selected, and the wheat variety was Jimai 22.

[0079] The specific method is as follows: the experiment has 6 treatments, each with an area of ​​1 mu. Before sowing, each treatment group uses conventional compound fertilizer (N: P2O5: K2O = 18: 15: 12) as base fertilizer and turns it into the soil at a rate of 50 kg / mu. Then, at the seedling stage, compound microbial agents numbered M1, M2, M3, M4, M5, and M6 are applied into the soil at a rate of 20 kg / mu. The rest of the management measures for each treatment group are conventional wheat field management measures. The formula composition and preparation method of the composite microbial agent of M1 are basically the same as those of Example 1, except that the mass ratio of the microbial agent to the carrier is 1:0; the formula composition and preparation method of the composite microbial agent of M2 are basically the same as those of Example 1, except that the mass ratio of the microbial agent to the carrier is 1:1; the formula composition and preparation method of the composite microbial agent of M3 are basically the same as those of Example 1, except that the mass ratio of the microbial agent to the carrier is 1:3; the composite microbial agent of M4 is the product prepared in Example 1; the formula composition and preparation method of the composite microbial agent of M5 are basically the same as those of Example 1, except that the mass ratio of the microbial agent to the carrier is 1:9; the formula composition and preparation method of the composite microbial agent of M6 are basically the same as those of Example 1, except that the mass ratio of the microbial agent to the carrier is 1:10. See the specific results for details. Figure 4 .

[0080] from Figure 4 It can be seen from the results that the ratio of the microbial agent and the carrier in the composite microbial agent prepared by the present invention has a significant effect on wheat yield. As can be seen from the figure, the wheat yield from M1 to M4 shows an increasing trend, while as the amount of carrier continues to increase, the wheat yield shows a downward trend. This is because the accumulation of rare earth elements will affect the composition of the soil microbial flora. When the proportion of carriers in the composite microbial agent increases, the content of rare earth element cerium increases accordingly, which may have different degrees of inhibitory effects on the activity of certain microorganisms, thereby reducing the activity of microorganisms and affecting the yield of wheat. Therefore, the composite microbial agent for wheat prepared by the present invention has the best ratio after experimental verification. If any component in the composite microbial agent for wheat used for increasing production of the present invention is reduced or changed, the corresponding effect disappears or weakens. Therefore, the components of the composite microbial agent for wheat used for increasing production of the present invention complement each other and are indispensable.

[0081] 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 increasing wheat yield, characterized in that: The invention comprises a microbial agent and a carrier, wherein the microbial agent comprises Bacillus velez, Arthrobacter bayleyi and Streptomyces tenuiflavos; the carrier is a rare earth modified diatomaceous earth composite; and the mass ratio of the microbial agent to the carrier is 1:5-8.

2. The composite microbial agent for increasing wheat yield according to claim 1, characterized in that: The rare earth modified diatomite composite is prepared by the following method: A: Mix diatomite, halloysite and starch in proportion, wet-mill for 1 hour using anhydrous ethanol as solvent, and then dry and sieve through a 200-mesh sieve to obtain a premix; B: Add an appropriate amount of 4wt% polyvinyl alcohol to the premix, grind for 10-20min, add it to a tube furnace and calcine at high temperature for 2h, and then grind it to obtain a diatomite-based porous material; C: Prepare a 0.2 mol / L cerium nitrate solution, immerse the diatomite-based porous material in it, let it stand for 24 hours, filter it, dry it in an oven, transfer it to a muffle furnace and calcine it for 3 hours, grind it into powder, and obtain a rare earth modified diatomite composite.

3. The composite microbial agent for increasing wheat yield according to claim 2, characterized in that: The mass ratio of the diatomite, halloysite and starch is 2:1:

10.

4. The composite microbial agent for increasing wheat yield according to claim 2, characterized in that: The dosage ratio of the premix to polyvinyl alcohol is 10 g:1 ml.

5. The composite microbial agent for increasing wheat yield according to claim 2, characterized in that: The high temperature calcination temperature in step B is 1000°C.

6. The composite microbial agent for increasing wheat yield according to claim 2, characterized in that: The usage ratio of the cerium nitrate solution to the diatomite-based porous material is 30 ml:1 g; and the calcination temperature of the muffle furnace is 300°C.

7. The composite microbial agent for increasing wheat yield according to claim 1, characterized in that: The Bacillus velezensis strain is numbered CGMCC No.1.12669, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation date is September 10, 2013; the Arthrobacter bayenii strain is numbered CGMCC No.1.10873, purchased from the China General Microbiological Culture Collection Administration Center, and the preservation time is April 1, 2011; the Streptomyces tenuifolius strain is numbered CGMCC No.4.6163, and the preservation time is September 3, 2008.

8. The composite microbial agent for increasing wheat yield according to claim 1, characterized in that: The preparation method of the microbial agent is as follows: Bacillus velez, Arthrobacter bayleyi, and Streptomyces tenuifolius are activated in YMA solid culture medium respectively, and then all are inoculated into a test tube of TY liquid culture medium, and cultured at 28°C and 200 r / min until OD 600 ≈2.0, inoculate 3% of the seed liquid into 200 mL of fermentation liquid medium, ferment and culture at 28°C and 200 r / min for 12 h, stop the fermentation to obtain three fermentation broths, and then mix them in a volume ratio of 1:1:1 to obtain the microbial agent.

9. The composite microbial agent for increasing wheat yield according to claim 8, characterized in that: The fermentation liquid culture medium is composed of: 10 g glucose, 10 g yeast powder, 1 g sodium chloride, 0.1 g MgSO4·7H2O, 0.1 g K2HPO4, 2 g (NH4)2SO4, 1000 ml distilled water, natural pH, sterilization conditions: 121°C, 30 min.

10. A method for preparing the composite microbial agent for increasing wheat yield according to any one of claims 1 to 9, characterized in that: It includes the following steps: (1) Preparation of rare earth modified diatomite composite materials; (2) Preparation of microbial agents; (3) The rare earth modified diatomaceous earth composite material obtained in step (1) is uniformly mixed with the microbial agent according to a mass ratio, and the final product is obtained after natural drying.

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