Microbial agent capable of overcoming successive cropping obstacles of beet and preparation method and application of microbial agent

Abstract

The invention provides a microbial agent for overcoming successive cropping obstacles of beet and a preparation method and application thereof, and belongs to the technical field of microbial agents. The microbial agent comprises the following components in parts by mass: 30-40 parts of sodium alginate, 60-70 parts of a bacterial liquid, 3-5 parts of charcoal, 2-4 parts of calcium chloride and 10-20 parts of a soil conditioner, the bacterial liquid comprises a micrococcus luteus GZU-Mi02 bacterial liquid, a fragrance-like fungus C40 bacterial liquid and a bacillus amyloliquefaciens Z-2 bacterial liquid. The microbial agent prepared by the invention not only can solve the successive cropping obstacle of beet, but also can promote growth of beet and increase income, and meanwhile, improves soil nutrients and structure, thereby fundamentally eliminating the successive cropping obstacle of beet.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial agents, and in particular to a microbial agent for overcoming obstacles of continuous sugar beet cropping, and a preparation method and application thereof. Background Art

[0002] Sugar beet is my country's second-largest sugar crop after sugarcane. my country's sugar beet cultivation area has been fluctuating upward, reaching a record high of 1.5 million tons in 2024, reaching 3.4 million mu (approximately 1.3 million hectares) of planted area and 1.5 million tons of sugar in 2024. Sugar beet is primarily cultivated in Heilongjiang, Inner Mongolia, and Xinjiang, with Inner Mongolia boasting the largest planting area, accounting for over 60% of the national total. Currently, there are 31 operating sugar beet production plants in my country, including 13 in Xinjiang, 12 in Inner Mongolia, 3 in Heilongjiang, and 3 in Gansu. Their daily processing capacity has reached 135,600 tons, and the sugar beet industry has experienced rapid growth. However, with the rapid growth of the sugar beet industry and the concentrated distribution of sugar beet production plants in major producing areas, the supply of raw materials has become a prominent issue in the industry. Given the limited arable land available and the difficulty of implementing a three- to four-year crop rotation, my country has adopted a widespread practice of continuous cropping. In major producing areas like Inner Mongolia and Xinjiang, continuous cropping accounts for an average of over 30% of the sugar beet area, with some regions exceeding 70%. Long-term continuous cropping of sugar beets has destroyed the diversity of soil microorganisms, caused the accumulation of pathogens, and increasingly serious soil-borne diseases, posing a serious threat to the yield and quality of sugar beets. Studies have shown that continuous cropping of sugar beets has caused a 30%-50% decrease in sugar beet yield and a 2-3 degree decrease in sugar content, which directly restricts the formation of sugar beet yield and affects the sustainable and efficient development of my country's sugar beet industry.

[0003] Studies have found that the main causes of continuous cropping problems include the following: First, the long-term cultivation of the same crop leads to a preference for soil nutrients, resulting in an imbalance in soil nutrients that are not replenished in a timely manner; second, changes in the structure of the soil microbial community, namely an increase in harmful bacteria and a decrease in beneficial bacteria, which aggravates diseases in the next crop; third, autotoxic substances secreted by crop roots or in their residues lead to a deterioration of the root zone environment and inhibit the growth of the next crop, namely allelopathic autotoxicity; fourth, soil acidification or salinization. The prevention and control of continuous cropping problems in sugar beets generally adopt several methods, including crop rotation, increased application of organic fertilizers, chemical control, and biological control. Reasonable crop rotation is the main technical way to regulate soil fertility and the ecological environment and improve soil continuous cropping problems. It is an important agricultural measure used in tomato cultivation. However, due to the limitations of farmers' cultivation technology and large-scale market demand, sugar beet cultivation is increasingly tending to be planted in large areas. Therefore, it is difficult to effectively implement crop rotation and rotation management measures in major sugar beet producing areas. The use of chemical soil disinfection and sterilization agents can lead to the development of drug resistance in pathogens, and pesticides gradually accumulate in the environment, resulting in pesticide pollution. Patent application number 200610201417.X discloses a composite microbial agent for preventing and controlling diseases caused by continuous cropping, and its preparation method. This composite microbial agent can achieve comprehensive control of continuous cropping diseases. However, in actual agricultural production, the effectiveness of biological agents is short-lived because they do not fundamentally change the physical and chemical properties of the soil. Secondary metabolites produced by plants remain in the soil, resulting in low viable counts of beneficial bacteria in the biofertilizer and ineffectiveness. Furthermore, due to significant differences in the accumulation of pathogens, secondary metabolites in the soil, and the degree of soil acidification or salinization, different crop types require crop-specific agents designed to overcome the problem of continuous cropping. However, there is currently no composite agent that overcomes the problem of continuous cropping of sugar beets. Summary of the Invention

[0004] In view of this, the present invention provides a microbial agent for overcoming the obstacles of continuous cropping of sugar beets, and a preparation method and application thereof, so as to fill the gaps in the prior art.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a microbial agent for overcoming the obstacles of continuous cropping of sugar beets, comprising the following components in parts by weight: 30-40 parts of sodium alginate, 60-70 parts of bacterial liquid, 3-5 parts of biochar, 2-4 parts of calcium chloride, and 10-20 parts of soil conditioner;

[0007] The bacterial liquid includes Micrococcus luteus GZU-Mi02 bacterial liquid, Bacillus amyloliquefaciens C40 bacterial liquid and Bacillus amyloliquefaciens Z-2 bacterial liquid.

[0008] Preferably, the ratio of the number of live bacteria of Micrococcus luteus GZU-Mi02, Bacillus amyloliquefaciens C40 and Bacillus amyloliquefaciens Z-2 is 1:1:2-3.

[0009] Preferably, the effective viable bacteria count in the bacterial solution of Micrococcus flavus GZU-Mi02, the bacterial solution of Bacillus amyloliquefaciens C40 and the bacterial solution of Bacillus amyloliquefaciens Z-2 is 1 to 9×10 8 cfu / mL.

[0010] Preferably, the biochar is prepared by mixing rice husks and corn straw in a mass ratio of 1:1.5-2.5 and anaerobically heating at 400-500° C. for 3-4 hours.

[0011] Preferably, the soil conditioner comprises the following components in percentage: SiO2 35-45%, CaO 20-30%, and light calcium carbonate 30-40%.

[0012] The present invention also provides a method for preparing the microbial agent, comprising the following steps:

[0013] S1. Micrococcus luteus GZU-Mi02, class aroma bacteria C40 and Bacillus amyloliquefaciens Z-2 were fermented and cultured separately, and the obtained bacterial solution was mixed in accordance with the proportion to obtain a mixed bacterial solution;

[0014] S2. A 3-4% sodium alginate solution was mixed with biochar, and then the mixed bacterial solution was added to obtain solution 1;

[0015] S3. Add calcium chloride solution dropwise to solution 1 and stir at 100-130 rpm for 2-4 h to obtain sodium alginate-biochar immobilized microspheres;

[0016] S4. Mixing the sodium alginate-biochar immobilized microspheres with a soil conditioner to obtain.

[0017] Preferably, the concentration of calcium chloride is 1-2%.

[0018] Preferably, Micrococcus luteus GZU-Mi02, Bacillus amyloliquefaciens C40 and Bacillus amyloliquefaciens Z-2 are all fermented and cultured using LB medium.

[0019] The present invention also provides the use of the microbial agent in overcoming the obstacles of continuous beet cropping or promoting the growth of beets.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects: the microbial agent of the present invention comprises the following components by weight: 30-40 parts sodium alginate, 60-70 parts bacterial solution, 3-5 parts biochar, 2-4 parts calcium chloride, and 10-20 parts soil conditioner; the bacterial solution comprises a solution of Micrococcus luteus GZU-Mi02, a solution of Bacillus amyloliquefaciens C40, and a solution of Bacillus amyloliquefaciens Z-2. The microbial agent prepared by the present invention not only solves the problem of continuous cropping of sugar beets, but also promotes sugar beet growth and increases income. It also improves soil nutrients and structure, thereby fundamentally eliminating the problem of continuous cropping of sugar beets. DETAILED DESCRIPTION

[0021] The present invention provides a microbial agent for overcoming the obstacles of continuous cropping of sugar beets, comprising the following components in parts by weight: 30-40 parts of sodium alginate, 60-70 parts of bacterial liquid, 3-5 parts of biochar, 2-4 parts of calcium chloride, and 10-20 parts of soil conditioner;

[0022] The bacterial liquid includes Micrococcus luteus GZU-Mi02 bacterial liquid, Bacillus amyloliquefaciens C40 bacterial liquid and Bacillus amyloliquefaciens Z-2 bacterial liquid.

[0023] In the microbial agent for overcoming the continuous cropping obstacle of sugar beets of the present invention, the mass fraction of the sodium alginate is preferably 32 to 38 parts, more preferably 35 parts;

[0024] The mass fraction of the bacterial liquid is preferably 63 to 67 parts, more preferably 65 parts;

[0025] The mass fraction of the biochar is preferably 3.5 to 4.5 parts, more preferably 4 parts;

[0026] The mass fraction of the calcium chloride is preferably 2.5 to 3.5 parts, more preferably 3 parts;

[0027] The mass fraction of the soil conditioner is preferably 12 to 18 parts, more preferably 15 parts;

[0028] The bacterial liquid includes Micrococcus luteus GZU-Mi02 bacterial liquid, Bacillus amyloliquefaciens C40 bacterial liquid and Bacillus amyloliquefaciens Z-2 bacterial liquid.

[0029] The inventors unexpectedly discovered in their research that Micrococcus luteus GZU-Mi02 has the ability to degrade 3-butylhexyl phthalate and benzaldehyde, two self-toxic substances in sugar beet cropping. There is little research on this strain in agriculture, and there are no reports that this strain can degrade crop self-toxic substances.

[0030] The aroma-like fungus C40 can degrade phenol and has good phosphorus and potassium solubilization capabilities, which can promote the growth of crops and improve the quality of crops.

[0031] Bacillus amyloliquefaciens Z-2 has a significant antagonistic effect on common pathogens that cause root rot of fruits and vegetables, and can effectively prevent and control root rot of fruits and vegetables; it also has a strong ability to produce indoleacetic acid and siderophore, which can promote the absorption of nutrients by plants.

[0032] The microbial combination of the present invention exhibits a synergistic effect in the degradation of beet self-sensing substances butyl-3-hexyl phthalate and benzaldehyde, which may be because their metabolites have a mutually promoting effect in the degradation of butyl-3-hexyl phthalate and benzaldehyde.

[0033] In the microbial agent of the present invention, the ratio of the viable bacteria count of the Micrococcus luteus GZU-Mi02, the aroma-like bacteria C40 and the Bacillus amyloliquefaciens Z-2 is 1:1:2-3, preferably 1:1:2.2-2.7, and more preferably 1:1:2.5. The effective viable bacteria count in the bacterial solution of Micrococcus luteus GZU-Mi02, the aroma-like bacteria C40 and the Bacillus amyloliquefaciens Z-2 is 1-9×10 8 cfu / mL.

[0034] In the present invention, the biochar is prepared by mixing rice husks and corn straws and anaerobically heating them. The mass ratio of the rice husks to the corn straws is 1:1.5-2.5, preferably 1:1.8-2.3, and more preferably 1:2.

[0035] The heating temperature is 400-500° C., more preferably 420-470° C., and even more preferably 450° C., and the heating time is 3-4 hours, and preferably 3.5 hours.

[0036] In the present invention, the soil conditioner includes the following components in percentage: SiO2 35-45%, CaO 20-30%, and light calcium carbonate 30-40%; the mass percentage of SiO2 is preferably 38-42%, more preferably 40%; the mass percentage of CaO is preferably 22-28%, more preferably 25%; the mass percentage of light calcium carbonate is preferably 33-37%, more preferably 35%.

[0037] The present invention also provides a method for preparing the microbial agent, comprising the following steps:

[0038] S1. Micrococcus luteus GZU-Mi02, class aroma bacteria C40 and Bacillus amyloliquefaciens Z-2 were fermented and cultured separately, and the obtained bacterial solution was mixed in accordance with the proportion to obtain a mixed bacterial solution;

[0039] S2. A 3-4% sodium alginate solution was mixed with biochar, and then the mixed bacterial solution was added to obtain solution 1;

[0040] S3. Add calcium chloride solution dropwise to solution 1 and stir at 100-130 rpm for 2-4 h to obtain sodium alginate-biochar immobilized microspheres;

[0041] S4. Mixing the sodium alginate-biochar immobilized microspheres with a soil conditioner to obtain.

[0042] The present invention involves fermenting and culturing Micrococcus luteus GZU-Mi02, Bacillus amyloliquefaciens C40, and Bacillus amyloliquefaciens Z-2 separately, obtaining bacterial broths that are then mixed in appropriate proportions to produce a mixed bacterial broth. The fermentation medium is LB medium. A sodium alginate solution is then mixed with biochar, and the mixed bacterial broth is added to produce Solution 1. The sodium alginate concentration is 3-4%, preferably 3.2-3.8%, and more preferably 3.5%.

[0043] In the present invention, a calcium chloride solution is added dropwise to solution 1, and cross-linking is performed while stirring to obtain sodium alginate-biochar immobilized microspheres. The concentration of the calcium chloride solution is 1-2%, more preferably 1.2-1.8%, and more preferably 1.5%. The stirring speed is 100-130 rpm, more preferably 110-120 rpm, and more preferably 115 rpm. The stirring time is 2-4 hours, preferably 2.5-3.5 hours, and more preferably 3 hours.

[0044] The invention obtains the sodium alginate-biochar immobilized microspheres by mixing the microspheres with a soil conditioner.

[0045] The present invention also provides the use of the microbial agent in overcoming the obstacles of continuous beet cropping or promoting the growth of beets.

[0046] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0047] The Micrococcus luteus GZU-Mi02 in the embodiment of the present invention was purchased from the China Center for Type Culture Collection with a deposit number of CCTCC NO: M2017514; the Aromatic Bacillus C40 was purchased from the General Microorganism Center of the China Culture Collection Administration Committee with a deposit number of CGMCC No. 20347; and the Bacillus amyloliquefaciens Z-2 was purchased from the General Microorganism Center of the China Culture Collection Administration Committee with a deposit number of CGMCC No. 20822.

[0048] Example 1

[0049] A microbial agent for overcoming the obstacle of continuous cropping of sugar beets is composed of the following components in parts by mass: 30g of sodium alginate, 60g of bacterial liquid, 3g of biochar, 2g of calcium chloride, and 10g of a soil conditioner.

[0050] Preparation method of the microbial agent for overcoming the obstacles of continuous beet cropping:

[0051] (1) Biochar preparation: Rice husk and corn straw were mixed in a mass ratio of 1:1.5 and anaerobically heated at 400 °C for 3 h.

[0052] (2) Preparation of soil conditioner: Mix 35 wt% SiO2, 25 wt% CaO and 40 wt% light calcium carbonate.

[0053] (3) Preparation of bacterial solution

[0054] After rejuvenation, primary expansion culture, and secondary expansion culture, Micrococcus luteus GZU-Mi02 was inoculated into LB culture medium at a 5% inoculum volume and fermented at 30° C. to the logarithmic phase.

[0055] After rejuvenation, primary expansion culture and secondary expansion culture, the aroma-like fungus C40 was inoculated into LB culture medium at a 5% inoculum amount and fermented at 35° C. to the logarithmic phase.

[0056] After rejuvenation, primary expansion culture and secondary expansion culture, Bacillus amyloliquefaciens Z-2 was inoculated into LB culture medium at an inoculum size of 5%, and fermented at 35° C. to the logarithmic phase.

[0057] Dilute the above bacterial solution to 1×10 8 cfu / mL, and mixed according to the volume ratio of 1:1:2 to obtain a mixed bacterial solution.

[0058] (4) Preparation of sodium alginate-biochar immobilized microspheres:

[0059] Biochar was added to a 3% sodium alginate solution, mixed well, and then the mixed bacterial solution was added to obtain solution 1. A 1% calcium chloride solution was added dropwise to solution 1, and stirred at 100 rpm for 2 h to obtain sodium alginate-activated carbon immobilized microspheres.

[0060] (5) Mixing the sodium alginate-activated carbon immobilized microspheres with a soil conditioner to obtain the product.

[0061] Example 2

[0062] A microbial agent for overcoming the obstacle of continuous cropping of sugar beets is composed of the following components in parts by mass: 35g of sodium alginate, 65g of bacterial liquid, 4g of biochar, 3g of calcium chloride, and 15g of a soil conditioner.

[0063] Preparation method of the microbial agent for overcoming the obstacles of continuous beet cropping:

[0064] (1) Biochar preparation: Rice husk and corn straw were mixed in a mass ratio of 1:2 and anaerobically heated at 450 °C for 3.5 h.

[0065] (2) Preparation of soil conditioner: Mix 40 wt% SiO2, 25 wt% CaO and 35 wt% light calcium carbonate.

[0066] (3) Preparation of bacterial solution

[0067] After rejuvenation, primary expansion culture, and secondary expansion culture, Micrococcus luteus GZU-Mi02 was inoculated into LB culture medium at a 5% inoculum volume and fermented at 30° C. to the logarithmic phase.

[0068] After rejuvenation, primary expansion culture and secondary expansion culture, the aroma-like fungus C40 was inoculated into LB culture medium at a 5% inoculum amount and fermented at 35° C. to the logarithmic phase.

[0069] After rejuvenation, primary expansion culture and secondary expansion culture, Bacillus amyloliquefaciens Z-2 was inoculated into LB culture medium at an inoculum size of 5%, and fermented at 35° C. to the logarithmic phase.

[0070] The above bacterial solution was diluted to 5×10 8 cfu / mL, and mixed according to the volume ratio of 1:1:2.5 to obtain a mixed bacterial solution.

[0071] (4) Preparation of sodium alginate-biochar immobilized microspheres:

[0072] Biochar was added to a 3-4% sodium alginate solution, mixed well, and then the mixed bacterial solution was added to obtain solution 1. A 1.5% calcium chloride solution was added dropwise to solution 1, and stirred at 120 rpm for 3 hours to obtain sodium alginate-activated carbon immobilized microspheres.

[0073] (5) Mixing the sodium alginate-activated carbon immobilized microspheres with a soil conditioner to obtain the product.

[0074] Example 3

[0075] A microbial agent for overcoming the obstacle of continuous cropping of sugar beets is composed of the following components in parts by mass: 40g of sodium alginate, 70g of bacterial liquid, 5g of biochar, 4g of calcium chloride, and 20g of a soil conditioner.

[0076] Preparation method of the microbial agent for overcoming the obstacles of continuous beet cropping:

[0077] (1) Biochar preparation: Rice husk and corn straw were mixed in a mass ratio of 1:2.5 and anaerobically heated at 500 °C for 4 h.

[0078] (2) Preparation of soil conditioner: Mix 40 wt% of SiO2, 30 wt% of CaO and 30 wt% of light calcium carbonate.

[0079] (3) Preparation of bacterial solution

[0080] After rejuvenation, primary expansion culture, and secondary expansion culture, Micrococcus luteus GZU-Mi02 was inoculated into LB culture medium at a 5% inoculum volume and fermented at 30° C. to the logarithmic phase.

[0081] After rejuvenation, primary expansion culture and secondary expansion culture, the aroma-like fungus C40 was inoculated into LB culture medium at a 5% inoculum amount and fermented at 35° C. to the logarithmic phase.

[0082] After rejuvenation, primary expansion culture and secondary expansion culture, Bacillus amyloliquefaciens Z-2 was inoculated into LB culture medium at an inoculum size of 5%, and fermented at 35° C. to the logarithmic phase.

[0083] The above bacterial solution was diluted to 9×10 8 cfu / mL, and mixed according to the volume ratio of 1:1:3 to obtain a mixed bacterial solution.

[0084] (4) Preparation of sodium alginate-biochar immobilized microspheres:

[0085] Biochar was added to a 4% sodium alginate solution, mixed well, and then the mixed bacterial solution was added to obtain solution 1. A 2% calcium chloride solution was added dropwise to solution 1, and stirred at 130 rpm for 4 hours to obtain sodium alginate-activated carbon immobilized microspheres.

[0086] (5) Mixing the sodium alginate-activated carbon immobilized microspheres with a soil conditioner to obtain the product.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that the aroma-like bacteria WNR22032 is used to replace the aroma-like bacteria C40.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that Bacillus amyloliquefaciens Z-2 was replaced by Bacillus amyloliquefaciens (deposit number CGMCC No. 17841).

[0091] Comparative Example 3

[0092] Different from Example 1, the bacterial liquid was not prepared into sodium alginate-activated carbon immobilized microspheres, but the bacterial liquid was prepared into bacterial powder by vacuum freeze-drying, and the bacterial powder was mixed with a soil conditioner to prepare a microbial agent.

[0093] Comparative Example 4

[0094] The publication number is "CN 112110771 A", and the invention name is "A soil remediation bacterial agent for preventing and controlling continuous cropping obstacles and its preparation method".

[0095] Experimental Example 1. Bacterial species interaction experiment

[0096] Tested strains:

[0097] 1. Micrococcus luteus GZU-Mi02, deposit number: CCTCC NO: M2017514;

[0098] 2. Aroma-like fungus C40, deposit number: CGMCC No.20347;

[0099] 3. Bacillus amyloliquefaciens Z-2, deposit number: CGMCC No. 20822;

[0100] 4. Aroma-like fungus WNR22032, deposit number: CCTCC No: 2024138;

[0101] 5. Bacillus amyloliquefaciens, deposit number: CGMCC No.17841;

[0102] 6. Bacillus subtilis Z-14, deposit number CGMCC No. 20821.

[0103] Above-mentioned tested strain is cultivated to logarithmic growth phase with LB liquid nutrient medium respectively, sampling is as seed liquor, and adopts different combinations to be inoculated in LB nutrient medium, observes the degradation effect for butyl 3-hexyl phthalate and benzaldehyde.The experimental group of different combination bacterium all cultivates with LB liquid nutrient medium and in nutrient medium, adds butyl 3-hexyl phthalate (5g / L) and benzaldehyde (5g / L), each experimental group is set 28 ℃, 180rpm in shaking incubator, cultivates after 10 days, adopts GC-MS method to detect wherein the content of butyl 3-hexyl phthalate and benzaldehyde after sampling (200mL).The LB liquid nutrient medium that only adds equal butyl 3-hexyl phthalate and benzaldehyde is set as blank control group.Simultaneously, the interaction of each bacterial species in the combined bacteria of each experimental group has also been studied, and result is as shown in Table 1.

[0104] Table 1 Interaction results of various bacterial species

[0105]

[0106] Note: “+” indicates that there is no growth inhibition among the strains; “-” indicates that there is growth inhibition among the strains.

[0107] As can be seen from Table 1, except for the "1+2+3" experimental group, the growth of each bacterial species in the other experimental groups was inhibited, and the "1+2+3" bacterial species combination had an excellent degradation effect on butyl-3-hexyl phthalate and benzaldehyde, with more than 90% of butyl-3-hexyl phthalate and benzaldehyde being degraded.

[0108] Experimental Example 2

[0109] The experiment was conducted in Pingdiquan Town, Ulanqab City, Inner Mongolia Autonomous Region. The sugar beet variety was IM1162. The selected experimental site had been planted with sugar beets for three consecutive years. When the experiment was conducted, it was the fourth year of planting. The experimental site was divided into several plots, each with an area of 300m 2 There was a 1m isolation zone between each plot. Sugar beets were planted at a density of 5500 plants / mu. There were 7 treatment groups in total, and the treatments were:

[0110] Treatment 1: conventional fertilization, and applying the microbial agent in Example 1 as base fertilizer, with an application amount of 2 kg / mu.

[0111] Treatment 2: conventional fertilization, and applying the microbial agent in Example 2 as base fertilizer, with an application amount of 2 kg / mu.

[0112] Process 3

[0113] Conventional fertilization was performed, and the microbial agent in Example 3 was applied as base fertilizer at an application rate of 2 kg / mu.

[0114] Process 4

[0115] Conventional fertilization was performed, and the microbial agent in Comparative Example 1 was applied as base fertilizer at an application rate of 2 kg / mu.

[0116] Process 5

[0117] Conventional fertilization was performed, and the microbial agent in Comparative Example 2 was applied as base fertilizer at an application rate of 2 kg / mu.

[0118] Process 6

[0119] Conventional fertilization was performed, and the microbial agent in Comparative Example 3 was applied as base fertilizer at an application rate of 2 kg / mu.

[0120] Process 7

[0121] Conventional fertilization was performed, and the microbial agent in Comparative Example 4 was applied as base fertilizer at an application rate of 2 kg / mu.

[0122] The planting area with conventional fertilization and no application of any microbial agents was used as a blank control. Each treatment group was replicated three times. The emergence rate, root rot incidence, per mu yield and sweetness of sugar beets in each group were statistically analyzed. The results are shown in Table 2.

[0123] Conventional fertilization is: 2500kg / mu of organic fertilizer, 10kg / mu of urea, 15kg / mu of diammonium phosphate, and 10kg / mu of potassium sulfate as base fertilizer, which are applied to the farmland once before planting. Seed fertilizer is applied 30 days after the beets emerge, with 6kg of superphosphate per mu. The first topdressing is after the seedlings are established and before the first watering, with 15kg of urea and 6kg of superphosphate per mu. The second topdressing is 4kg of urea.

[0124] Table 2 Seedling rate, root rot incidence and per mu yield of sugar beets in each group

[0125]

[0126]

[0127] As shown in Table 2, the per-acre yield and emergence rate of sugar beets in the Examples of the present invention were higher than those in the Comparative Example and the blank group, and the incidence of root rot was reduced. A comparison between the Examples and Comparative Example 3 shows that the sodium alginate-biochar immobilized microspheres prepared by the present invention can improve the survival rate of microorganisms in the inoculant. The microbial inoculant of the present invention can effectively alleviate the problem of continuous cropping of sugar beets.

[0128] After sugar beet harvest, soil from each treatment was collected and its basic physical and chemical properties, microbial content, and urease activity were measured. Soil pH was measured using the potentiometric method, organic matter using the potassium dichromate volumetric method, total nitrogen using the acid oxidation method, available phosphorus using the molybdenum blue colorimetric method, and available potassium using the sodium tetraphenylborate turbidimetric method. Soil bulk density and porosity were determined using the ring knife method. The results of the soil physical and chemical properties are shown in Table 3, and the microbial content and urease activity are shown in Table 4.

[0129] Table 3 Soil nutrient and structure indicators of each group

[0130]

[0131] As shown in Table 3, the microbial agent of the present invention significantly reduced the soil bulk density, significantly increased the soil porosity, effectively improved the soil acidity, increased the content of organic matter in the soil, and increased the content of available phosphorus and available potassium.

[0132] Table 4 Soil urease activity and microbial activity

[0133]

[0134]

[0135] As shown in Table 4, the microbial agent of the present invention can increase urease activity and microbial abundance.

[0136] It can be seen from the above embodiments that the present invention provides a microbial agent for overcoming the obstacles of continuous beet cropping, and a preparation method and application thereof. The microbial agent prepared by the present invention can be used to improve soil where continuous beet cropping obstacles exist.

[0137] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A microbial agent for overcoming the obstacles of continuous cropping of sugar beets, characterized in that: The invention comprises the following components in parts by weight: 30-40 parts of sodium alginate, 60-70 parts of bacterial liquid, 3-5 parts of biochar, 2-4 parts of calcium chloride, and 10-20 parts of soil conditioner; The bacterial liquid includes Micrococcus luteus GZU-Mi02 bacterial liquid, Bacillus amyloliquefaciens C40 bacterial liquid and Bacillus amyloliquefaciens Z-2 bacterial liquid.

2. The microbial agent according to claim 1, characterized in that The ratio of the number of live bacteria of the Micrococcus luteus GZU-Mi02 bacteria, the aroma-like bacteria C40 bacteria and the Bacillus amyloliquefaciens Z-2 bacteria is 1:1:2-3.

3. The microbial agent according to claim 1, characterized in that The effective viable bacteria count in the bacterial liquid of Micrococcus flavus GZU-Mi02, the bacterial liquid of Bacillus amyloliquefaciens C40 and the bacterial liquid of Bacillus amyloliquefaciens Z-2 is 1 to 9×10 8 cfu / mL.

4. The microbial agent according to claim 1, characterized in that The biochar is prepared by mixing rice husks and corn straw in a mass ratio of 1:1.5-2.5 and anaerobically heating at 400-500° C. for 3-4 hours.

5. The biological agent according to claim 1, characterized in that The soil conditioner comprises the following components in percentage: SiO2 35-45%, CaO 20-30%, and light calcium carbonate 30-40%.

6. The method for preparing the microbial agent according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Micrococcus luteus GZU-Mi02, class aroma bacteria C40 and Bacillus amyloliquefaciens Z-2 were fermented and cultured separately, and the obtained bacterial solution was mixed in accordance with the proportion to obtain a mixed bacterial solution; S2. A 3-4% sodium alginate solution was mixed with biochar, and then the mixed bacterial solution was added to obtain solution 1; S3. Add calcium chloride solution dropwise to solution 1 and stir at 100-130 rpm for 2-4 h to obtain sodium alginate-biochar immobilized microspheres; S4. Mixing the sodium alginate-biochar immobilized microspheres with a soil conditioner to obtain.

7. The preparation method according to claim 6, characterized in that The concentration of the calcium chloride is 1-2%.

8. The preparation method according to claim 6, characterized in that Micrococcus luteus GZU-Mi02, Bacillus amyloliquefaciens C40 and Bacillus amyloliquefaciens Z-2 were all fermented using LB medium.

9. Use of the microbial agent according to any one of claims 1 to 5 in overcoming obstacles to continuous cropping of sugar beets or promoting the growth of sugar beets.

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