Compound microbial agent and application thereof in improving saline-alkali stress resistance of crops

Abstract

The invention discloses a compound microbial agent and application thereof to improvement of saline-alkali stress resistance of crops. The compound microbial agent is prepared from the following components in parts by weight: 1 to 3 parts of bacillus cereus, 1 to 3 parts of bacillus megatherium, 6 to 8 parts of rhizopus heterotropoides, 50 to 70 parts of gypsum powder, 10 to 30 parts of humic acid, 2 to 3 parts of yeast metabolite, 2 to 5 parts of aluminum sulfate, 2 to 5 parts of citric acid and 0.4 to 0.6 part of an auxiliary agent. The bacillus cereus, the bacillus megatherium and the rhizopus heterosporioides are combined for the first time, the biological functions of the bacillus cereus, the bacillus megatherium and the rhizopus heterosporioides are synergistically exerted, the growth performance of crops under saline-alkali stress is remarkably improved, the physicochemical properties and nutrient conditions of saline-alkali soil are effectively improved by adding humic acid, yeast metabolite and other components, the soil fertility is improved, and the saline-alkali soil quality is improved. Meanwhile, a favorable environment is provided for the growth of the microbial agent; the plant root activity is remarkably improved, the salt tolerance of crops under the salt and alkali stress condition is improved, the growth state of the plants is improved, and therefore the yield of the crops is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural microorganisms, and in particular to a composite microbial agent and application thereof in improving the ability of crops to resist salt-alkali stress. Background Art

[0002] Saline-alkali land refers to land where excessive saline and alkali components accumulate on the soil surface, which has an adverse effect on the growth of crops. It is a general term for salt land, alkali land, salinized land and alkalized land. Saline-alkali land usually has the following characteristics: high saline-alkali content in the soil, compacted texture, alkaline soil, low organic matter content, nutrient imbalance, and low biological activity. As an important reserve arable land resource in my country, the development and improvement of saline-alkali land is of great significance for expanding the area of ​​arable land, improving land use efficiency, and ensuring food security. The improvement methods of saline-alkali land mainly include four aspects: physical, chemical, biological and comprehensive management. Among them, biological improvement is one of the most effective methods. Its principle is to absorb, transform and transport soil salt through the growth and metabolic activities of plants or microorganisms, thereby improving soil quality.

[0003] Bacillus cereus and Bacillus megaterium are common salt-tolerant bacteria, and are currently widely used as microbial agents in agriculture. Liu Xin et al. (CN114214245A) discovered a strain of Bacillus cereus SS1, which has salt-alkali tolerance and drought resistance, can significantly alleviate the harm caused to plants by drought stress, can significantly improve the salt-tolerance and drought-tolerance growth-promoting ability of plants under stress, and slow down the harm caused to plants under stress conditions, thereby promoting their growth. Zhang Ruifu et al. (CN109897806A) discovered a strain of Bacillus megaterium T4-9, which can improve the salt stress resistance of crops, increase crop yields and reduce soil salt content.

[0004] Arbuscular mycorrhizal fungi are widely distributed in soil ecosystems and can form symbioses with the roots of more than 80% of terrestrial higher plants - arbuscular mycorrhizal fungi. By interacting with plant roots, arbuscular mycorrhizal fungi significantly improve the tolerance of plants to saline-alkali stress and promote the absorption of water and nutrients in the soil by plants, especially the effective utilization of phosphorus. Although the effects of Bacillus cereus, Bacillus megaterium and arbuscular mycorrhizal fungi in individual applications have been widely studied and confirmed, there are currently no reports on the combination of the three to improve the ability of crops to resist saline-alkali stress. Summary of the invention

[0005] In view of the above-mentioned prior art, the purpose of the present invention is to provide a composite microbial agent and its application in improving the ability of crops to resist salt-alkali stress.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a composite microbial agent, comprising the following ingredients in parts by weight: 1-3 parts of Bacillus cereus, 1-3 parts of Bacillus megaterium, 6-8 parts of Rhizospora heteromorpha, 10-30 parts of humic acid, 50-70 parts of gypsum powder, 2-3 parts of yeast metabolites, 2-5 parts of aluminum sulfate, 2-5 parts of citric acid and 0.4-0.6 parts of additives.

[0008] The invention uses Bacillus cereus, Bacillus megaterium, Rhizosporium heteromorphum, humic acid, yeast metabolites and the like as raw materials to prepare a microbial agent for improving the salt-alkali stress tolerance of plants. The Bacillus cereus can produce extracellular polysaccharide EPS to stimulate the antioxidant activity of plant cells to increase the expression of salt-alkali tolerance genes, and regulate ion metabolic pathways to improve the salt-alkali tolerance of plants; Bacillus megaterium can secrete phosphatase and organic acid to decompose and activate organic phosphorus and insoluble inorganic phosphorus, and reduce soil pH; Rhizosporium heteromorphum can enhance the plant's ability to absorb water and nutrients (especially phosphorus) by forming arbuscular mycorrhiza with plants. ) absorption capacity, thereby significantly improving the growth performance of crops under saline-alkali stress; humic acid can provide good conditions for the reproduction of microorganisms and give full play to the transformation effect of microorganisms. On the other hand, it can chelate some metal cations in saline-alkali soil to reduce salt concentration; yeast metabolites are rich in various amino acids, biochemical fulvic acid and other organic substances, which can provide nutrients required for activation of microorganisms in the bacterial agent; acidic conditioners such as gypsum powder, aluminum sulfate, citric acid and microbial composite powder work together to condition the soil, so that the alkaline soil can obtain a more lasting conditioning effect, achieving long-term and thorough improvement of the alkaline soil.

[0009] Preferably, the composite microbial agent comprises the following components in parts by weight:

[0010] 2 parts of Bacillus cereus, 2 parts of Bacillus megaterium, 8 parts of Rhizospora heteromorpha, 20 parts of humic acid, 60 parts of gypsum powder, 3 parts of yeast metabolites, 2 parts of aluminum sulfate, 2.5 parts of citric acid and 0.5 parts of auxiliary agent.

[0011] Preferably, the deposit number of Bacillus cereus is CGMCC No.33090, and the deposit number of Rhizospora heteromorpha is CGMCC No.41723.

[0012] Preferably, the number of live bacteria of the Bacillus cereus is ≥10 billion / gram, the number of live bacteria of the Bacillus megaterium is ≥10 billion / gram, and the number of effective reproductive bodies of the Rhizospora heteromorpha is ≥70 / gram.

[0013] Preferably, the auxiliary agent is one or more of Chunzhisu No. 2, Jinggen, and Huangpeptideamine.

[0014] The second aspect of the present invention provides a method for preparing the composite microbial agent, comprising the following steps: weighing each raw material according to weight, mixing each raw material evenly, and obtaining the composite microbial agent.

[0015] The third aspect of the present invention provides the use of the above-mentioned composite microbial agent in improving the ability of crops to resist salt-alkali stress.

[0016] Preferably, the composite microbial agent improves the resistance of crops to salt-alkali stress by at least one of the following ways (1)-(5):

[0017] (1) Improve the germination rate of crops under saline-alkali stress;

[0018] (2) Increase the stem thickness of crops under saline-alkali stress;

[0019] (3) Increase plant height of crops under saline-alkali stress;

[0020] (4) Improve the chlorophyll SPAD value of crops under saline-alkali stress;

[0021] (5) Improve crop yields under saline-alkali stress.

[0022] Beneficial effects of the present invention:

[0023] 1. The present invention combines Bacillus cereus, Bacillus megaterium and Rhizosporium heteromorphum for the first time to synergistically exert their biological functions. Bacillus cereus upregulates the expression of salt-alkali tolerance genes by stimulating the antioxidant activity of plant cells, and improves the salt-alkali tolerance of plants by regulating ion metabolic pathways; Bacillus megaterium can secrete phosphatase and organic acid to decompose and activate organic phosphorus and insoluble inorganic phosphorus, and reduce soil pH; Rhizosporium heteromorphum enhances the plant's absorption capacity for water and nutrients (especially phosphorus) by forming arbuscular mycorrhizae with plants, thereby significantly improving the growth performance of crops under salt-alkali stress; by adding components such as potassium humate, acidic conditioners and yeast metabolites, the present invention effectively improves the physical and chemical properties and nutrient status of saline-alkali soil, improves soil fertility, and provides a favorable environment for the growth of microbial agents.

[0024] 2. The present invention significantly enhances the vitality of plant roots through the action of composite microbial agents, improves the tolerance of crops to salt under saline-alkali stress conditions, improves the growth state of plants, and thus increases crop yields. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : Germination rate of corn seeds with different treatments under salt stress;

[0026] Figure 2 : Physiological parameters of corn seeds with different treatments grown in saline-alkali land. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0028] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0029] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0030] The potassium humate used in the present invention was purchased from Shandong Agricultural University Fertilizer Technology Co., Ltd.

[0031] The yeast metabolites used in the present invention were purchased from Angel Yeast (Binzhou) Co., Ltd.

[0032] The purchase sources of the auxiliary agents used in the present invention are as follows:

[0033] Chunzhisu No. 2 was purchased from Henan Zhongwei Chunyu Plant Nutrition Co., Ltd.;

[0034] Jingen was purchased from Henan Xuyang Agricultural Technology Co., Ltd.;

[0035] Huangpeptide amine was purchased from Henan Ennuo Agricultural Technology Co., Ltd.

[0036] The Bacillus cereus used in the present invention is named SNF7, and the deposit information is as follows:

[0037] Bacteria name: Bacillus cereus SNF7

[0038] Latin name: Bacillus cereus

[0039] Depository: China National Microbiological Culture Collection Administration General Microbiology Center

[0040] Abbreviation of depository institution: CGMCC

[0041] Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing

[0042] Deposit date: December 17, 2024

[0043] Deposit number: CGMCC No.33090.

[0044] The Bacillus cereus of the present invention is added in the form of bacterial powder, and the preparation method of Bacillus cereus is as follows:

[0045] The activated Bacillus cereus SNF7 seed liquid was inoculated into LB liquid culture medium at an inoculation rate of 10% (volume fraction), and cultured in a shaking incubator at 35°C and 180rpm for 36h. The culture liquid was centrifuged (4,000rpm, 10 minutes), the supernatant was discarded, the precipitated bacteria were collected and dried to obtain Bacillus cereus powder. The number of live bacteria in the Bacillus cereus powder was determined to be 10 billion / g.

[0046] The Rhizophagus irregularis used in the present invention is named NDFY-Ri1, and the deposit information is as follows:

[0047] Strain name: Heteromorpha rhizosporangiophora NDFY-Ri1

[0048] Latin name: Rhizophagus irregularis

[0049] Depository: China National Microbiological Culture Collection Administration General Microbiology Center

[0050] Abbreviation of depository institution: CGMCC

[0051] Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing

[0052] Deposit date: December 17, 2024

[0053] Deposit number: CGMCC No.41723.

[0054] The heteromorphic Rhizosporium of the present invention is added in the form of bacterial powder, and the preparation method of the heteromorphic Rhizosporium powder is as follows:

[0055] The whole culture of Heteromorph Rhizosporangium NDFY-Ri1 after single spore culture was inoculated into sandy soil culture matrix at an inoculation amount of 1% (mass fraction), 8 corn seeds were sown according to the size of the pot, and cultured at 25°C for 3 months. The aboveground part of the corn was cut off, the culture matrix and all the roots were collected, crushed, dried and sieved through a 1mm sieve to obtain Heteromorph Rhizosporangium powder. It was determined that the number of propagules of Heteromorph Rhizosporangium was ≥70 / g.

[0056] The Bacillus megaterium used in the present invention is purchased from Shandong Agricultural University Fertilizer Technology Co., Ltd., and the trade name is "Yuanjuntai-Super Concentrated Agricultural Microbial Agent Bacillus megaterium", with a bacterial content of 10 billion / gram.

[0057] Example 1: Preparation of composite microbial agent:

[0058] (1) Raw material composition (parts by weight):

[0059] 2 parts of Bacillus cereus, 2 parts of Bacillus megaterium, 8 parts of Rhizospora heteromorpha, 20 parts of humic acid, 60 parts of gypsum powder, 3 parts of yeast metabolites, 2 parts of aluminum sulfate, 2.5 parts of citric acid and 0.5 parts of Spring Element No. 2;

[0060] (2) Preparation method:

[0061] The above raw materials are weighed according to weight proportions, and the raw materials are evenly mixed to obtain a composite microbial agent.

[0062] Embodiment 2:

[0063] (1) Raw material composition (parts by weight):

[0064] 1 part of Bacillus cereus, 1 part of Bacillus megaterium, 6 parts of Rhizospora heteromorpha, 10 parts of humic acid, 60 parts of gypsum powder, 2 parts of yeast metabolites, 2 parts of aluminum sulfate, 2 parts of citric acid and 0.4 parts of Radix Glycyrrhizae.

[0065] The preparation method is the same as that in Example 1 to prepare a composite microbial agent.

[0066] Embodiment 3:

[0067] (1) Raw material composition (parts by weight):

[0068] 3 parts of Bacillus cereus, 3 parts of Bacillus megaterium, 8 parts of Rhizospora heteromorpha, 3 parts of humic acid, 70 parts of gypsum powder, 3 parts of yeast metabolites, 5 parts of aluminum sulfate, 5 parts of citric acid and 0.6 parts of flavonoids;

[0069] The preparation method is the same as that in Example 1 to prepare a composite microbial agent.

[0070] Comparative Example 1:

[0071] Raw material composition (parts by weight):

[0072] Humic acid 20 parts, gypsum powder 60 parts, yeast metabolites 3 parts, aluminum sulfate 2 parts, citric acid 2.5 parts and Spring Element No. 2 0.5 parts;

[0073] (2) Preparation method:

[0074] The above raw materials are weighed according to weight proportions, and the raw materials are evenly mixed to obtain a composite microbial agent.

[0075] Comparative Example 2:

[0076] Raw material composition (parts by weight):

[0077] 2 parts of Bacillus cereus, 20 parts of humic acid, 60 parts of gypsum powder, 3 parts of yeast metabolites, 2 parts of aluminum sulfate, 2.5 parts of citric acid and 0.5 parts of Spring Element No. 2;

[0078] (2) Preparation method:

[0079] The above raw materials are weighed according to weight proportions, and the raw materials are evenly mixed to obtain a composite microbial agent.

[0080] Comparative Example 3:

[0081] Raw material composition (parts by weight):

[0082] 2 parts of Bacillus megaterium, 20 parts of humic acid, 60 parts of gypsum powder, 3 parts of yeast metabolites, 2 parts of aluminum sulfate, 2.5 parts of citric acid and 0.5 parts of Spring Element No. 2;

[0083] (2) Preparation method:

[0084] The above raw materials are weighed according to weight proportions, and the raw materials are evenly mixed to obtain a composite microbial agent.

[0085] Comparative Example 4:

[0086] Raw material composition (parts by weight):

[0087] 8 parts of Rhizospora heteromorpha, 20 parts of humic acid, 60 parts of gypsum powder, 3 parts of yeast metabolites, 2 parts of aluminum sulfate, 2.5 parts of citric acid and 0.5 parts of Spring Element No. 2;

[0088] (2) Preparation method:

[0089] The above raw materials are weighed according to weight proportions, and the raw materials are evenly mixed to obtain a composite microbial agent.

[0090] Experimental Example 1: Indoor bioassay of the effect of composite microbial agents on corn germination under salt stress

[0091] 1. Test method:

[0092] Select corn seeds that are not damaged, have full grains, and are uniform in size for use, fill a germination box with 1 kg of nutrient soil as a matrix, drip NaCl solutions of different concentrations into the germination box to make the matrix salt content reach 0.6%, 1.2%, 1.8%, 2.4% and 3%, respectively, with distilled water as a control. Then, sow the seeds simultaneously with the composite microbial agent prepared in Example 1 and the fertilizer prepared in Comparative Examples 1-3, with 20 seeds in each box, and repeat 4 times.

[0093] There are 6 treatment groups in the experiment:

[0094] Treatment 1: Apply the composite microbial agent prepared in Example 1 at a treatment concentration of 40 kg / mu;

[0095] Treatment 2: Apply the composite microbial agent prepared in Example 2 at a treatment concentration of 40 kg / mu;

[0096] Treatment 3: Apply the composite microbial agent prepared in Example 3 at a treatment concentration of 40 kg / mu;

[0097] Treatment 4: applying the fertilizer prepared in Comparative Example 1 at a treatment concentration of 40 kg / mu;

[0098] Treatment 5: Apply the fertilizer prepared in Comparative Example 2 at a treatment concentration of 40 kg / mu;

[0099] Treatment 6: Apply the fertilizer prepared in Comparative Example 3 at a treatment concentration of 40 kg / mu;

[0100] Treatment 7: Apply the fertilizer prepared in Comparative Example 4 at a treatment concentration of 40 kg / mu;

[0101] Control group: no fertilizer.

[0102] The germination boxes will be placed in a light culture room for cultivation, and water will be added regularly to maintain the concentration of the salt solution.

[0103] Detection method: Count the number of seeds that germinate every day. If the number of germinated seeds does not increase for 3 consecutive days after germination begins, germination is considered complete.

[0104] The seed germination rate was determined according to the following formula.

[0105] Germination rate (%) = (total number of normal germinations / total number of test seeds) × 100%.

[0106] 2. Test results:

[0107] Figure 1 It shows that with the increase of salt concentration, the germination rate of all groups is on a downward trend. The germination rate of CK (control group) decreases relatively greatly. When the salt concentration reaches 3%, the germination rate drops to about 79%. The germination rate of Examples 1, 2, and 3 decreases relatively slowly. When the salt concentration is 3%, the germination rate can still be maintained at about 93%, indicating that the treatment methods in these embodiments can alleviate the negative impact of salt concentration on the germination rate to a certain extent and improve the germination ability of seeds in saline-alkali environments. The germination rate of Comparative Examples 1, 2, 3, and 4 decreases between CK and the embodiments, indicating that the synergistic effect of Bacillus cereus, Bacillus megaterium, and Rhizosporium heteromorphum in the embodiments is better than the effect of a single strain.

[0108] Test Example 2: Field test on the effect of composite microbial agent on corn growth under salt stress

[0109] Experimental treatment: The saline-alkali land in Wudi County, Binzhou City, Shandong Province was selected for field experiment. The soil physical and chemical properties are shown in Table 1.

[0110] Table 1 Basic physical and chemical properties of soil in the test site

[0111]

[0112] The experimental treatments were:

[0113] T1: conventional fertilization (CK);

[0114] T2: conventional fertilization + compound microbial agent (40kg / mu) treatment, the compound microbial agent was used as part of the base fertilizer and applied together with other base fertilizers;

[0115] T3: conventional fertilization + fertilizer prepared in Comparative Example 1 (40 kg / mu), the fertilizer prepared in Comparative Example 1 was used as part of the basal fertilizer and applied together with other basal fertilizers;

[0116] T4: conventional fertilization + fertilizer prepared in Comparative Example 2 (40 kg / mu), the fertilizer prepared in Comparative Example 2 was used as part of the basal fertilizer and applied together with other basal fertilizers;

[0117] T5: conventional fertilization + fertilizer prepared in Comparative Example 3 (40 kg / mu) treatment, the fertilizer prepared in Comparative Example 3 was used as part of the basal fertilizer and applied together with other basal fertilizers.

[0118] T6: conventional fertilization + fertilizer prepared in Comparative Example 4 (40 kg / mu) treatment, the fertilizer prepared in Comparative Example 4 was used as part of the basal fertilizer and applied together with other basal fertilizers.

[0119] Each treatment was set up with 3 replications and arranged in random blocks. The sown corn was grown in a natural environment, and other field managements except basal fertilizer were the same.

[0120] Detection method:

[0121] In early September 2024, when corn was in the flaring stage, the row spacing and plant spacing of corn were measured respectively. Twelve corn plants were randomly selected from each treatment, and the plant height, stem diameter and chlorophyll content were measured on the spot.

[0122] In October 2024, corn is in the harvest period. Three sampling points are randomly selected in each plot. A tape measure is used to measure the 3m area at each sampling point, and the number of corn plants and corn ears on both sides of the tape measure are counted. In each statistical sample section, 40 ears of corn are continuously collected to measure the quality and calculate the yield.

[0123] Table 2 Theoretical yield of corn field test

[0124]

[0125] Test results: Figure 2The results showed that the application of composite microbial agents and single microbial agents can promote the growth of corn under saline-alkali soil conditions, but the composite microbial agent has the highest growth-promoting effect. Specifically, the plant height of T2 increased by 27.00%, 14.54%, 4.6%, 5.38% and 4.65% respectively compared with the control, comparative examples 1, 2, 3, and 4, and the stem diameter increased by 21.64%, 5.75%, 2.36%, 5.07% and 2.04% respectively compared with the control, comparative examples 1, 2, 3, and 4, and the chlorophyll SPAD value increased by 17.94%, 13.99%, 6.76%, 7.33 and 1.35% respectively compared with the control, control, comparative examples 1, 2, 3, and 4. Table 2 shows that the composite microbial agent significantly increased the yield of corn under saline-alkali soil conditions.

[0126] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A composite microbial agent, characterized in that: The composition comprises the following components in parts by weight: 1-3 parts of Bacillus cereus, 1-3 parts of Bacillus megaterium, 6-8 parts of Rhizospora heteromorpha, 10-30 parts of humic acid, 50-70 parts of gypsum powder, 2-3 parts of yeast metabolites, 2-5 parts of aluminum sulfate, 2-5 parts of citric acid and 0.4-0.6 parts of auxiliary agents.

2. The composite microbial agent according to claim 1, characterized in that: The composition comprises the following components in parts by weight: 2 parts of Bacillus cereus, 2 parts of Bacillus megaterium, 8 parts of Rhizospora heteromorpha, 20 parts of humic acid, 60 parts of gypsum powder, 3 parts of yeast metabolites, 2 parts of aluminum sulfate, 2.5 parts of citric acid and 0.5 parts of auxiliary agent.

3. The composite microbial agent according to claim 1, wherein the number of viable bacteria of the Bacillus cereus is ≥ 10 billion / gram, the number of viable bacteria of the Bacillus megaterium is ≥ 10 billion / gram, and the number of effective propagules of the Rhizospora heteromorpha is ≥ 70 / gram.

4. The composite microbial agent according to claim 1, characterized in that: The deposit number of Bacillus cereus is CGMCC No.33090, and the deposit number of Rhizospora heteromorpha is CGMCC No.41723.

5. The composite microbial agent according to claim 1, characterized in that: The auxiliary agent is one or more of Chunzhisu No. 2, Jinggen, and Huangpeptideamine.

6. Use of the composite microbial agent according to any one of claims 1 to 5 in improving the ability of crops to resist salt-alkali stress.

7. The use according to claim 6, characterized in that: The composite microbial agent improves the resistance of crops to salt-alkali stress by at least one of the following ways (1)-(5): (1) Improve the germination rate of crops under saline-alkali stress; (2) Increase plant height of crops under saline-alkali stress; (3) Increase the stem thickness of crops under saline-alkali stress; (4) Improve the chlorophyll SPAD value of crops under saline-alkali stress; (5) Improve crop yields under saline-alkali stress.

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