A liquid composite microbial fertilizer from yeast and a preparation method and application thereof

Abstract

This invention belongs to the field of microbial fertilizer technology, specifically disclosing a liquid yeast-derived compound microbial fertilizer, its preparation method, and its application. The liquid yeast-derived compound microbial fertilizer contains yeast fermentation waste liquid, inorganic fertilizer, functional microbial strains, and a suspending agent. The yeast fermentation waste liquid contains betaine. The preparation method includes the following steps: after extracting yeast from molasses production, the concentrated yeast fermentation waste liquid is mixed evenly with a certain proportion of inorganic fertilizer, functional microbial strains, and a suspending agent to obtain the liquid compound microbial fertilizer. The liquid compound microbial fertilizer obtained by the preparation method of this invention has soil-improving, growth-promoting, and stress-resistant effects.

Description

Technical Field

[0001] This invention belongs to the field of microbial fertilizer technology, specifically relating to a yeast-derived liquid compound microbial fertilizer, its preparation method, and its application. Background Technology

[0002] Yeast metabolites originate from the yeast fermentation industry. They are high-concentration yeast wastewater produced during yeast production and treated with anaerobic fermentation. This wastewater contains abundant organic matter, nitrogen, phosphorus, potassium, calcium, iron, crude protein, amino acids, pigments, pectin, and other substances. The total amount of wastewater discharged from producing one ton of dry yeast is about 70 tons. Direct discharge of this wastewater will lead to a large amount of soil and water pollution, seriously damaging the existing ecological environment and becoming a bottleneck restricting the development of domestic yeast enterprises.

[0003] Microbial fertilizers encompass three main categories: bio-organic fertilizers, microbial inoculants, and compound microbial fertilizers. Proper application of microbial fertilizers can reduce chemical fertilizer usage, lower production costs, improve soil structure, eliminate soil compaction, improve crop quality, and increase marketability, ultimately significantly enhancing economic benefits. They are ideal production materials for green food. Currently, the organic fertilizer in compound microbial fertilizers primarily uses livestock and poultry manure as the main raw material for fermentation. The yeast fermentation waste liquid contains abundant organic matter, sugars, amino acids, etc., providing ample carbon and nitrogen sources and growth factors for microbial growth, while also offering some protection to functional microorganisms. Using yeast fermentation waste liquid as the main raw material to prepare compound microbial fertilizers can effectively alleviate the environmental pressure caused by yeast waste liquid discharge and increase the nutrient and organic matter content of functional microorganisms, meeting the needs of crop growth. Therefore, how to prepare microbial fertilizers using yeast fermentation waste liquid as the main raw material and apply them to the soil to promote crop growth is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The technical problem solved by this invention is that the existing technology for preparing compound microbial fertilizers is complex and costly. This invention utilizes yeast metabolites as resources to provide agriculture with nutritious, high-quality, safe and efficient microbial fertilizers, which is in line with the current strategy of ecological protection and sustainable development.

[0005] To address the above problems, the present invention aims to provide a yeast-derived liquid compound microbial fertilizer, its preparation method, and its application.

[0006] Specifically, the present invention proposes the following technical solution.

[0007] In a first aspect, the present invention provides a liquid compound microbial fertilizer containing yeast fermentation waste liquid, inorganic fertilizer, functional microbial strains and suspending agents; wherein the yeast fermentation waste liquid contains betaine.

[0008] Preferably, by weight, it contains 50-99 parts yeast fermentation waste liquid, 1-20 parts inorganic fertilizer, 0.5-5 parts functional microbial strains and 0.1-2 parts suspending agent.

[0009] Preferably, by weight, it contains 80-95 parts yeast fermentation waste liquid, 10-20 parts inorganic fertilizer, 0.5-1 parts functional microbial strains and 0.1-2 parts suspending agent.

[0010] More preferably, by weight, it contains 87-95 parts yeast fermentation waste liquid, 10-20 parts inorganic fertilizer, 0.5-1 parts functional microbial strains and 0.1-2 parts suspending agent.

[0011] Preferably, the yeast fermentation waste liquid is produced by extracting yeast from molasses, followed by evaporation, concentration, and refining. The solid content in the concentrated yeast fermentation waste liquid is 40wt% to 60wt%. More preferably, the solid content in the yeast fermentation waste liquid is 45wt% to 55wt%.

[0012] Preferably, the molasses contains beet molasses;

[0013] More preferably, the molasses is selected from beet molasses, or a mixture of beet molasses and sugarcane molasses, glucose molasses and starch hydrolyzed molasses, or a combination of two or more of these.

[0014] More preferably, the molasses is selected from beet molasses and / or cane molasses.

[0015] Preferably, the inorganic fertilizer is selected from one or more of urea, monoammonium phosphate, diammonium phosphate, potassium dihydrogen phosphate, or potassium sulfate; more preferably, the inorganic fertilizer is selected from urea and / or diammonium phosphate.

[0016] Preferably, the functional microbial strain is selected from one or more of Bacillus subtilis, Bacillus licheniformis, Bacillus laterosporus, Bacillus mucilaginosus, methyltrophic bacteria, Bacillus megaterium, and Bacillus belesii.

[0017] Preferably, the functional microbial strains are selected from one or more of Bacillus subtilis, Bacillus lateralis, and Bacillus licheniformis;

[0018] Preferably, the functional microbial strain is selected from Bacillus subtilis and Bacillus brevis; more preferably, the weight ratio of Bacillus subtilis and Bacillus brevis is (1-9):(1-5); or the functional microbial strain is selected from Bacillus licheniformis and Bacillus brevis, more preferably, the weight ratio of Bacillus licheniformis and Bacillus brevis is (1-9):(1-5); or the functional microbial strain is selected from Bacillus subtilis.

[0019] More preferably, the viable count of Bacillus subtilis is 100 to 1000 billion / g; and / or the viable count of Bacillus lateralis is 50 to 100 billion / g; and / or the viable count of Bacillus licheniformis is 100 to 1000 billion / g.

[0020] Preferably, the suspending agent is selected from one or more of diatomaceous earth, bentonite, or attapulgite powder, with attapulgite powder being the preferred choice.

[0021] Preferably, the liquid compound microbial fertilizer contains 1 wt% to 10 wt% betaine; preferably, the betaine content is 2 wt% to 8 wt%; and / or, the liquid compound microbial fertilizer contains 20 wt% to 40 wt%, preferably 30 wt% to 40 wt% organic matter; and / or, the total content of nitrogen, phosphorus and potassium is 6 wt% to 25 wt%; and / or the effective viable bacteria count is 1 to 2 billion / mL.

[0022] Secondly, the present invention provides a method for preparing a liquid compound microbial fertilizer, comprising the following steps:

[0023] (1) After extracting yeast from molasses, yeast fermentation waste liquid is obtained by evaporation and concentration;

[0024] (2) Mix yeast fermentation waste liquid, inorganic fertilizer and suspending agent to obtain a mixture;

[0025] (3) Add the functional microbial strains to the mixture obtained in step (2) and mix evenly to prepare liquid compound microbial fertilizer.

[0026] Preferably, in step (2), the reaction temperature is 20–70°C, more preferably 40–50°C; and / or the reaction time is 5–12 h.

[0027] Preferably, in step (3), the reaction temperature is 20–42°C, more preferably 30–40°C; and / or the reaction time is 2–7 h.

[0028] Preferably, the liquid compound microbial fertilizer is used for fertilizing crops in saline-alkali soil.

[0029] Preferably, the compound liquid microbial fertilizer is applied by drip irrigation or fertigation.

[0030] Preferably, the compound microbial fertilizer can be applied to the entire plant or parts of the plant for fertilization.

[0031] Beneficial effects of the present invention

[0032] (1) Low-cost resource utilization: The compound microbial fertilizer of the present invention uses yeast fermentation waste liquid as the main raw material, which reduces the external addition of organic matter and nutrients, thereby reducing production costs.

[0033] (2) Simplify the process and extend the shelf life of the product.

[0034] (3) It has the functions of promoting growth and resisting stress on plants: The compound microbial fertilizer of the present invention contains a large amount of nutrients, organic matter, biochemical humic acid, amino acids and betaine and other functional substances, which have the functions of improving soil, promoting growth and resisting stress.

[0035] (4) Convenient application, water-saving and efficient: The compound microbial fertilizer of the present invention has low water-insoluble content and is fully water-soluble, making it suitable for drip irrigation, micro-spraying and other integrated water and fertilizer systems. Attached Figure Description

[0036] Figure 1 This shows the salt tolerance test results of the strains used in the examples.

[0037] Figure 2 The stability diagram shows the effective live bacteria in the fertilizers obtained in Examples 1-3.

[0038] Figure 3 The image shows the growth of corn seedlings obtained after fertilizer treatment in Examples 1-3.

[0039] Figure 4 The image shows the average stem length of corn seedlings obtained after fertilizer treatment in Examples 1-3.

[0040] Figure 5 The image shows the growth of maize seedlings obtained after fertilizer treatment in Example 1 and Comparative Examples 1-2.

[0041] Figure 6 The graph shows the average stem length and average maximum root length of maize seedlings obtained after fertilizer treatment in Example 1 and Comparative Examples 1-2.

[0042] Figure 7 The growth diagram shows the growth of maize seedlings obtained after fertilizer treatment in Examples 1, 4, 5 and Comparative Example 3.

[0043] Figure 8 The graph shows the average stem length of maize seedlings obtained after fertilizer treatments in Examples 1, 4, 5 and Comparative Example 3. Detailed Implementation

[0044] As described above, the purpose of this invention is to provide a yeast-derived liquid compound microbial fertilizer, its preparation method, and its application. This product combines yeast fermentation waste liquid with salt-tolerant functional microbial agents, resulting in a product that contains microorganisms, nutrients, organic matter, and betaine, etc., providing growth promotion, nutrient supply, and stress resistance functions for crops. Specifically, the betaine and Bacillus contained in the microbial fertilizer have a synergistic effect, effectively enhancing the crop's resistance to salt and alkali stress.

[0045] Yeast fermentation waste liquid is a pollutant emitted during yeast production, primarily originating from molasses itself. Yeast fermentation utilizes the fermentable sugars in molasses, while substances not absorbed by the yeast and metabolic byproducts are ultimately discharged as wastewater. Therefore, yeast fermentation waste liquid contains abundant cellulose, colloidal substances, caramel, and various complex organic compounds, as well as rich inorganic trace elements such as nitrogen, phosphorus, potassium, calcium, and iron, and organic substances such as humic acid and fulvic acid, exhibiting excellent fertilizing effects. This invention does not specifically limit the source of the yeast fermentation waste liquid; commercially available products familiar to those skilled in the art can be used. In this invention, the yeast fermentation waste liquid is preferably sourced from Angel Yeast Co., Ltd. The role of Bacillus in microbial fertilizers is mainly reflected in two aspects: firstly, meeting product indicator requirements to ensure the effective viable bacteria count in the fertilizer product reaches the standard; secondly, fulfilling functional needs by improving crop disease and drought resistance, fixing nitrogen, dissolving phosphorus and potassium, and promoting the decomposition, transformation, and utilization of organic matter. Under external environmental stress, betaine is one of the most important metabolic accumulation products of plants, which can stabilize cell structure. Bacillus can colonize both the rhizosphere and foliage. Under stress conditions, it can significantly increase catalase, peroxidase, superoxide dismutase, etc., thereby improving plant growth. That is, betaine and Bacillus in microbial fertilizer have a synergistic effect.

[0046] Suspension aid: The attapulgite powder used in the invention serves as a suspending agent and carrier. It has multiple pore sizes, good wettability, good thickening properties, and good suspension properties. It can stabilize the shape of liquid fertilizer, prevent stratification, and improve fertilizer efficacy. It is an excellent aid for liquid fertilizer.

[0047] In one specific embodiment of the present invention, a liquid compound microbial fertilizer is provided, which, by weight, contains 50-99 parts yeast fermentation waste liquid, 1-20 parts inorganic fertilizer, 0.5-5 parts functional microbial strains and 0.1-2 parts suspending agent; wherein the yeast fermentation waste liquid contains betaine.

[0048] Preferably, by weight, the liquid compound microbial fertilizer contains 50-99 parts yeast fermentation waste liquid, 1-20 parts inorganic fertilizer, 0.5-5 parts functional microbial strains and 0.1-2 parts suspension additive; wherein, the liquid compound microbial fertilizer contains 1wt%-10wt% betaine.

[0049] Preferably, by weight, the liquid compound microbial fertilizer contains 50-99 parts yeast fermentation waste liquid, 1-20 parts inorganic fertilizer, 0.5-5 parts functional microbial strains and 0.1-2 parts suspension additive; wherein, the liquid compound microbial fertilizer contains 2wt%-8wt% betaine.

[0050] In another specific embodiment of the present invention, a method for preparing a compound microbial fertilizer is provided, comprising the following steps:

[0051] (1) After extracting yeast from molasses, the yeast fermentation waste liquid is obtained by evaporation and concentration, and then naturally settled for more than 7 days. The supernatant is then taken for use.

[0052] (2) Mix yeast fermentation waste liquid, inorganic fertilizer and suspension aid, and react at a temperature of 20-70℃ for 5-12 hours to obtain a mixed liquid;

[0053] (3) Add the functional microbial strains to the above mixture and mix evenly. The reaction temperature is 20-42℃ and the reaction time is 2-7h to obtain liquid compound microbial fertilizer.

[0054] Preferably, the compound microbial fertilizer of the present invention is used in the field of salt-alkali resistant fertilizer.

[0055] Preferably, the compound microbial fertilizer of the present invention can be used for fertilization of crops in saline-alkali soil.

[0056] Preferably, the compound microbial fertilizer of the present invention is suitable for fertilization of crops throughout their entire growth period.

[0057] Preferably, the compound microbial fertilizer of the present invention can be applied by drip irrigation or fertigation.

[0058] Preferably, the compound microbial fertilizer of the present invention can be applied to the fertilization of the whole plant or parts of the plant.

[0059] The reagents / instruments used in the following examples are all commercially available products unless otherwise stated. The sources of the reagents and instruments used in the examples are shown in the table below:

[0060] Table 1. Reagents and instruments used in the examples and comparative examples.

[0061] Beet Molasses Sugar content 40% Xinjiang Sifang Industrial Co., Ltd. Molasses Sugar content 48% Lutang Sugar Factory, Guangxi Zhuang Autonomous Region urea Agricultural grade Hubei Saning Chemical Co., Ltd. Diammonium phosphate Agricultural grade Hubei Saning Chemical Co., Ltd. Attapulgite powder Agricultural grade Leihang Mineral Products Processing Plant, Lingshou County, Henan Province Bacillus subtilis powder 100 billion / g Hubei Qiming Biotechnology Co., Ltd. Lateral spores of Bacillus brevis powder 10 billion / g Hubei Qiming Biotechnology Co., Ltd. Bacillus licheniformis powder 100 billion / g Hubei Qiming Biotechnology Co., Ltd.

[0062] The determination of key indicators for microbial fertilizer products refers to the People's Republic of China Agricultural Industry Standard NY / T798-2015 Compound Microbial Fertilizer.

[0063] Salt tolerance tests were conducted on the Bacillus strains used in the preparation of yeast-derived liquid microbial fertilizer in this embodiment of the invention. First, samples of Bacillus subtilis powder, Bacillus licheniformis powder, and Bacillus laterosporus powder were prepared and sterile nutrient agar (NA) plates were prepared and left to stand for 24 hours. Then, 10g of each of the above powder samples (accurate to 0.01g) was weighed and added to a 500mL Erlenmeyer flask containing 100mL of sterile water and glass beads, and allowed to stand for 20min. The flask was then shaken thoroughly at 200r / min for 30min. The bacterial suspension was serially diluted 1:10 to obtain 1:10 solutions. 2 1:10 3 1:10 4 1:10 5 1:10 6 1:10 7 1:10 8 1:10 9 For a 1:10 dilution of bacterial suspension, accurately pipette 0.1 mL of the suspension. 9 The bacterial suspension was added dropwise to a pre-prepared NA medium plate and spread evenly using a sterile spreader. The plate was then incubated upside down at 30°C until uniform single colonies appeared. Single colonies were picked and streaked onto NA medium plates, and then inoculated onto nutrient agar plates containing 0, 2%, 4%, 6%, 8%, 10%, and 12% NaCl, prepared 24 hours in advance. Colony growth was observed over 5 days. Results are as follows: Figure 1 As shown, Group 1 contains Bacillus subtilis, Group 2 contains Bacillus licheniformis, and Group 3 contains Bacillus laterosporus. From left to right in the image, the plates inoculated with these strains are nutrient agar plates containing 0, 2%, 4%, 6%, 8%, 10%, and 12% NaCl, respectively. Figure 1 It can be seen that the microbial agents used in the embodiments of the present invention can grow at salt concentrations of 0% to 12%, and colony growth is slightly inhibited as the salt concentration increases.

[0064] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0065] Example 1

[0066] Add 90 parts by weight of yeast fermentation waste liquid with a solid content of 55% to the reactor. The culture medium used for yeast fermentation is beet molasses. Then add 10 parts by weight of urea and mix well. Next, add 0.5 parts by weight of attapulgite powder to the mixed solution and stir for 5 hours at 50°C until well mixed. Finally, add 0.6 parts by weight of Bacillus subtilis and Bacillus lateralis compound powder (weight ratio of 1:1) to the reactor and stir for 5 hours at 37°C until well mixed. The resulting reaction solution is liquid compound microbial fertilizer.

[0067] Example 2

[0068] Add 86 parts by weight of yeast fermentation waste liquid with a solid content of 53% to the reactor. The culture medium used for yeast fermentation is a mixture of beet molasses and cane molasses with a weight ratio of 2:1. Then add 13 parts by weight of diammonium phosphate. Next, add 0.5 parts by weight of attapulgite powder to the mixed solution and stir and chelate at 45°C for 8 hours. Finally, add 0.6 parts by weight of a mixture of Bacillus licheniformis and Bacillus retroflexus powder (weight ratio of 1:1) to the reactor and stir at 40°C for 3 hours until the mixture is homogeneous. The resulting reaction solution is the liquid compound microbial fertilizer.

[0069] Example 3

[0070] Add 83 parts by weight of yeast fermentation waste liquid with a solid content of 50% to the reactor. The culture medium used for yeast fermentation is a mixture of beet molasses and cane molasses with a weight ratio of 1:1. Then add 16 parts by weight of diammonium phosphate. Next, add 0.5 parts by weight of attapulgite powder to the mixed solution and stir at 45°C for 8 hours. Finally, add 0.5 parts by weight of Bacillus subtilis powder to the reactor and stir at 40°C for 3 hours until the mixture is homogeneous. The resulting reaction solution is the liquid compound microbial fertilizer.

[0071] Example 4

[0072] Add 50 parts by weight of yeast fermentation waste liquid with a solid content of 55% to the reactor. The culture medium used for yeast fermentation is beet molasses. Then add 1 part by weight of urea. Next, add 0.1 parts by weight of attapulgite powder to the mixed solution and stir at 45°C for 8 hours. Finally, add 2.5 parts by weight of Bacillus subtilis and Bacillus laterosporus brevis (weight ratio of 1:1) compound bacterial powder to the reactor and stir evenly at 40°C for 3 hours. The resulting reaction solution is the liquid compound microbial fertilizer.

[0073] Example 5

[0074] Add 75 parts by weight of yeast fermentation waste liquid with a solid content of 55% to the reactor. The culture medium used for yeast fermentation is beet molasses. Then add 10 parts by weight of urea. Next, add 2 parts by weight of attapulgite powder to the mixed solution and stir at 45°C for 8 hours. Finally, add 5 parts by weight of Bacillus subtilis and Bacillus laterosporus brevis (weight ratio of 1:1) compound bacterial powder to the reactor and stir evenly at 40°C for 3 hours. The resulting reaction solution is the liquid compound microbial fertilizer.

[0075] Comparative Example 1

[0076] Compared with Example 1, no functional bacterial powder was added. The remaining components and steps were the same as in Example 1, specifically including the following steps: 90 parts by weight of yeast fermentation waste liquid with a solid content of 55% was added to the reaction vessel. The culture medium used for yeast fermentation was beet molasses. Then, 10 parts by weight of urea were added and mixed evenly. Then, 0.5 parts by weight of attapulgite powder were added to the mixed solution and stirred at 50°C for 5 hours. The resulting reaction solution was the liquid compound fertilizer.

[0077] Comparative Example 2

[0078] Compared with Example 1, the culture medium used for yeast fermentation was sugarcane molasses, while the other components and steps were the same as in Example 1. The specific steps are as follows: 90 parts by weight of yeast fermentation waste liquid with a solid content of 55% were added to the reactor. The culture medium used for yeast fermentation was sugarcane molasses. Then, 10 parts by weight of urea were added and mixed evenly. Next, 0.5 parts by weight of attapulgite powder were added to the mixed solution and stirred at 50°C for 5 hours. Finally, 0.6 parts by weight of a compound bacterial powder of Bacillus subtilis and Bacillus laterosporus (weight ratio of 1:1) was added to the reactor and stirred at 37°C for 5 hours until evenly mixed. The resulting reaction solution is the liquid compound fertilizer.

[0079] Comparative Example 3

[0080] Compared with Example 1, the compound functional bacterial powder of Bacillus subtilis and Bacillus laterosporus was added in 0.3 parts, and the remaining components and steps were the same as in Example 1. The specific steps are as follows: 90 parts by weight of yeast fermentation waste liquid with a solid content of 55% was added to the reaction vessel. The culture medium used for yeast fermentation was beet molasses. Then, 10 parts by weight of urea were added and mixed evenly. Then, 0.5 parts by weight of attapulgite powder were added to the mixed solution and stirred at 50°C for 5 hours. Finally, 0.3 parts by weight of the compound bacterial powder of Bacillus subtilis and Bacillus laterosporus (weight ratio of 1:1) was added to the reaction vessel and stirred at 37°C for 5 hours until evenly mixed. The resulting reaction solution is the liquid compound fertilizer.

[0081] The key product indicators of the fertilizers prepared in each embodiment and comparative example were tested, as shown in the table below:

[0082] Table 2 Indicators of Fertilizer Products

[0083]

[0084] As can be seen from the table above, the key indicators such as the number of effective viable bacteria, nutrients, and organic matter in the compound microbial fertilizers prepared in Examples 1-5 all meet the industry standards for compound microbial fertilizers, and are qualified microbial fertilizer products. Comparative Examples 1 and 3, however, did not meet the standard for the number of effective viable bacteria, meaning their resulting compound microbial fertilizer products were unqualified.

[0085] On the other hand, the shelf life of the microbial fertilizers prepared in the examples and comparative examples was tested. The microbial fertilizers prepared in Examples 1-3 were packaged into glass blue-capped bottles and stored at room temperature. The effective viable count of Bacillus was determined using the plate count method. Data were collected over one year, averaging once a month. Figure 2 As shown, the results indicate that the number of viable Bacillus bacteria in the samples obtained in Examples 1-3 is relatively stable, with fluctuations within 10% over one year, indicating that the product has stable performance and a long shelf life. The specific operating steps of the plate count method are as follows:

[0086] Prepare sterile nutrient agar (NA) plates and let them stand for 24 hours. Accurately measure 10 mL of liquid microbial fertilizer and add it to a 500 mL Erlenmeyer flask containing glass beads and 100 mL of sterile water. Let it stand for 20 minutes. Shake thoroughly on a shaker at 200 rpm for 30 minutes. Serially dilute the bacterial suspension 1:10 to obtain 1:10 solutions. 2 1:10 3 1:10 4 1:10 5 1:10 6 1:10 7 1:10 8 1:10 9 For each diluted bacterial suspension, accurately pipette 0.1 mL of the suspension and add it dropwise to a pre-prepared NA medium plate. Spread the plate evenly using a sterile spreader. Incubate upside down in a 30°C incubator for 24–30 hours, then count the bacterial suspensions. Take 1:10 of each sample. 7 1:10 8 1:10 9For each dilution of bacterial suspension, three replicates were performed, with sterile water as a blank control. After incubation, if no colonies were observed in the blank control, the colony morphology on the NA plates was observed. Based on the technical data of the tested bacterial species, viable bacteria were confirmed using techniques such as smearing, staining, and microscopic examination. Plates with 30–300 colonies / plate were used as the counting standard. When selecting a single dilution of bacterial suspension, if the average colony count is between 30 and 300 / plate, that average is used for counting. If two dilutions are selected, and both have an effective average colony count between 30 and 300 / plate, the ratio of the colony averages of the two dilutions should be used. If the ratio is less than or equal to 2, the average of the two dilutions should be counted; if it is greater than 2, the average of the smaller dilution is counted. The colony average is the arithmetic mean of the effective colony counts on the three replicate plates for each dilution. The formula for calculating the effective viable bacteria count is: viable bacteria count per mL of sample (CFU / mL) = average number of colonies × dilution factor × 10.

[0087] Application Example 1

[0088] An indoor pot experiment was conducted using maize seeds as the research object. The experiment was divided into six groups: a water control group (CK water group), a saline control group (CK saline group), Example 1 group, Example 2 group, Example 3 group, and a control group. The maize seeds were first treated to induce germination. When the seeds had just sprouted, they were transplanted into a mixed substrate of vermiculite and peat moss in a 1:1 ratio. When the maize seedlings reached 3 cm in height, except for the water group which was watered with 100 mL of water, each experimental group's pot was watered with 100 mL of 1wt% NaCl saline solution. One day later, liquid fertilizer was applied to each pot of maize seedlings. The water group and the CK saline group were watered with 100 mL of water. Example 1-3 groups were watered with the liquid microbial fertilizer obtained in Example 1-3, respectively. The control group was watered with commercially available liquid fertilizer manufactured by Tianjin Kunhe Biotechnology Group. In Examples 1-3 and the control group, the fertilizer applied was 1g of liquid fertilizer diluted 200 times, and then 100mL of the diluted liquid fertilizer was applied to the corn seedlings and the growth was observed.

[0089] The growth of corn seedlings one week later is as follows Figure 3 As shown, the plant height of maize seedlings in each experimental group was measured to obtain the average and standard deviation of the plant height of maize seedlings under different treatment conditions, and a bar chart was created, as shown. Figure 4 As shown. From Figure 4It can be seen that the average stem length of the corn seedlings treated with the liquid fertilizer obtained in Examples 1-3 was higher than that of the CK salt water group, indicating that the liquid fertilizer obtained in Examples 1-3 has a significant growth-promoting effect on crops under salt stress and has the function of alleviating salt stress. Moreover, the average stem length of the corn seedlings treated with the liquid fertilizer in Examples 1-3 was higher than that of the control group, indicating that the liquid fertilizer prepared by the present invention has a higher ability to alleviate salt stress and promote crop growth than existing liquid fertilizers on the market.

[0090] Application Example 2

[0091] An indoor pot experiment was conducted using maize seeds as the research object and coconut coir as the substrate. Five experimental groups were established: the control group (water), the control group (salt water), Example 1 group, Comparative Example 1 group, and Comparative Example 2 group. Maize seeds were first pre-germinated, and seeds with uniform growth were sown. Once the stems reached 2-3 cm in length, except for the water group which received 100 mL of water, each experimental group's pots were filled with 100 mL of 1wt% NaCl saline solution. One day later, liquid fertilizer was applied to the maize seedlings in each pot: 100 mL of water to the water group, 100 mL of water to the control group (salt water), the liquid microbial fertilizer obtained in Example 1 to the Example 1 group, the liquid microbial fertilizer obtained in Comparative Example 1 to the Comparative Example 2 group, and the liquid microbial fertilizer obtained in Comparative Example 2 to the Comparative Example 2 group. In Example 1 and Comparative Examples 1-2, the fertilizer applied was 1g of liquid fertilizer diluted 200 times, and then 100mL of the diluted liquid fertilizer was applied to the corn seedlings, and the growth was observed.

[0092] The growth of the corn seedlings one week later is shown in the following figure. Figure 5 As shown, the stem length and maximum root length of maize seedlings in each experimental group were then measured to obtain the average stem length and average maximum root length of maize seedlings treated under different conditions, as shown in the figure. Figure 6 As shown. From Figure 6 It can be seen that the average stem length and maximum root length of the corn seedlings in Example 1 group were much higher than those in the CK salt water group and the water group, indicating that the liquid fertilizer prepared by this invention can significantly improve the crop's ability to resist salt stress. Data from Example 1 group, Comparative Example 1 group, and Comparative Example 2 group show that the average stem length and maximum root length of the corn seedlings in Example 1 group were higher than those in the comparative example group, indicating that the synergistic effect between betaine and functional microbial agents in the liquid fertilizer of this invention can alleviate the damage of salt stress to crops and promote crop growth.

[0093] Application Example 3

[0094] An indoor pot experiment was conducted using maize seeds as the research object and coconut coir and nutrient soil as the substrate. The experiment was divided into six groups: Example 1, Example 4, Example 5, Comparative Example 3, CK (salt solution) group, and CK (water) group. Maize seeds were first pre-germinated. Seeds with uniform growth were selected for sowing. When the stems reached 2-3 cm in length, except for the water group which received 100 mL of water, each pot was treated with 100 mL of 1wt% NaCl saline solution. One day later, liquid fertilizer was applied to the maize seedlings in each pot: 100 mL of water to the water group, 100 mL of water to the CK (salt solution) group, the liquid microbial fertilizer obtained in Example 1 to the Example 1 group, the liquid microbial fertilizer obtained in Example 4 to the Example 4 group, the liquid microbial fertilizer obtained in Example 5 to the Example 5 group, and the liquid microbial fertilizer obtained in Comparative Example 3 to the Comparative Example 3 group. In Example 1, Example 4, Example 5 and Comparative Example 3, 1g of liquid fertilizer was diluted 200 times, and 100mL of the diluted liquid fertilizer was then applied to the corn seedlings to observe their growth.

[0095] The growth of the corn seedlings one week later is shown in the following figure. Figure 7 As shown, the plant height of maize seedlings in each experimental group was then measured to obtain the average and standard deviation of the plant height of maize seedlings under different treatments, and corresponding bar charts were created, as shown. Figure 8 As shown. From Figure 8 It can be seen that the average stem length of maize seedlings in Examples 1, 4, and 5 is much higher than that in the control (CK) salt water group, indicating that the liquid fertilizer prepared by this invention can significantly improve the crop's ability to resist salt stress. Data from Comparative Example 3 and Examples 1, 4, and 5 show that the average plant height of maize seedlings in Examples 1, 4, and 5 is much higher than that in Comparative Example 3, further demonstrating that the synergistic effect between the specific ratio of betaine and functional microbial agents in the liquid microbial fertilizer of this invention can alleviate the damage caused by salt stress in crops and promote crop growth.

[0096] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A liquid compound microbial fertilizer for promoting crop growth in saline-alkali soils, characterized in that, It is composed of 80-95 parts yeast fermentation waste liquid, 10-20 parts inorganic fertilizer, 0.5-1 parts functional microbial strains and 0.1-2 parts suspension aid; wherein, the yeast fermentation waste liquid contains betaine; the betaine content in the liquid compound microbial fertilizer is 1wt%-10wt%; the inorganic fertilizer is urea and / or diammonium phosphate; The functional microbial strain is a mixture of Bacillus subtilis and Bacillus laterosporus brevis in a weight ratio of 1-9:1-5; or a mixture of Bacillus licheniformis and Bacillus laterosporus brevis in a weight ratio of 1-9:1-5; wherein the viable count of Bacillus subtilis is 100-1000 billion / g; the viable count of Bacillus laterosporus brevis is 50-100 billion / g; and the viable count of Bacillus licheniformis is 100-1000 billion / g. The preparation method of the liquid compound microbial fertilizer includes the following steps: (1) After extracting yeast from molasses, yeast fermentation waste liquid is obtained by evaporation and concentration; (2) Mix the yeast fermentation waste liquid, inorganic fertilizer and suspension aid at a temperature of 40~50℃ to obtain a mixed liquid; (3) Add the functional microbial strains to the mixture obtained in step (2) and mix them evenly at a temperature of 30~40 ℃ to prepare liquid compound microbial fertilizer.

2. The liquid compound microbial fertilizer according to claim 1, characterized in that, The yeast fermentation waste liquid is produced by extracting yeast from molasses, followed by evaporation, concentration and refining. The solid content in the evaporated and concentrated yeast fermentation waste liquid is 40wt%~60wt%.

3. The liquid compound microbial fertilizer according to claim 1, characterized in that, The yeast fermentation waste liquid is produced by extracting yeast from molasses, followed by evaporation, concentration and refining. The solid content in the evaporated and concentrated yeast fermentation waste liquid is 45wt%~55wt%.

4. The liquid compound microbial fertilizer according to claim 2, characterized in that, The molasses contains beet molasses.

5. The liquid compound microbial fertilizer according to claim 2, characterized in that, The molasses is selected from beet molasses, or a mixture of beet molasses and sugarcane molasses, glucose molasses and starch hydrolyzed molasses, or a combination of two or more of these.

6. The liquid compound microbial fertilizer according to claim 2, characterized in that, The molasses is selected from beet molasses and sugarcane molasses.

7. The liquid compound microbial fertilizer according to any one of claims 1-6, characterized in that, The suspending agent is selected from one or more of diatomaceous earth, bentonite, or attapulgite powder.

8. The liquid compound microbial fertilizer according to any one of claims 1-6, characterized in that, The suspending agent is attapulgite powder.

9. The liquid compound microbial fertilizer according to any one of claims 1-6, characterized in that, The liquid compound microbial fertilizer contains 2wt% to 8wt% betaine.

10. The liquid compound microbial fertilizer according to any one of claims 1-6, characterized in that, The liquid compound microbial fertilizer contains 20wt% to 40wt% organic matter; and / or the total content of nitrogen, phosphorus and potassium is 6wt% to 25wt%; and / or the number of effective live bacteria is 1 to 2 billion / mL.

11. The liquid compound microbial fertilizer according to claim 7, characterized in that, The liquid compound microbial fertilizer contains 20wt% to 40wt% organic matter; and / or the total content of nitrogen, phosphorus and potassium is 6wt% to 25wt%; and / or the number of effective live bacteria is 1 to 2 billion / mL.

12. The liquid compound microbial fertilizer according to claim 9, characterized in that, The liquid compound microbial fertilizer contains 20wt% to 40wt% organic matter; and / or the total content of nitrogen, phosphorus and potassium is 6wt% to 25wt%; and / or the number of effective live bacteria is 1 to 2 billion / mL.

13. The liquid compound microbial fertilizer according to claim 10, characterized in that, The organic matter content in the liquid compound microbial fertilizer is 30wt%~40wt%.

14. A method for preparing a liquid compound microbial fertilizer according to any one of claims 1-13, comprising the following steps: (1) After extracting yeast from molasses, yeast fermentation waste liquid is obtained by evaporation and concentration; (2) Mix the yeast fermentation waste liquid, inorganic fertilizer and suspension aid at a temperature of 40~50℃ to obtain a mixed liquid; (3) Add the functional microbial strains to the mixture obtained in step (2) and mix them evenly at a temperature of 30~40 ℃ to prepare liquid compound microbial fertilizer.

15. The method for preparing liquid compound microbial fertilizer according to claim 14, characterized in that, In step (2), the reaction time is 5 to 12 hours.

16. The method for preparing liquid compound microbial fertilizer according to claim 14 or 15, characterized in that, In step (3), the reaction time is 2 to 7 hours.

17. The method for preparing liquid compound microbial fertilizer according to claim 14 or 15, characterized in that, In step (3), the reaction time is 3 to 5 hours.

18. A liquid compound microbial fertilizer, characterized in that, The microbial fertilizer is prepared by the method for preparing liquid compound microbial fertilizer according to any one of claims 14-17.

19. The liquid compound microbial fertilizer according to any one of claims 1-13 or the liquid compound microbial fertilizer according to claim 18 is used for fertilization of crops in saline-alkali soil; And / or the compound liquid microbial fertilizer is applied by drip irrigation or fertigation; And / or the compound microbial fertilizer can be applied to the whole plant or parts of the plant for fertilization.

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