Microbial carrier and preparation method thereof, compound microbial agent and preparation method and application thereof

Abstract

The invention discloses a microbial carrier and a preparation method thereof, a composite microbial agent and a preparation method and application thereof, the microbial carrier provided by the invention takes a cross-linked body formed by cross-linking a phosphorite thermal activation product and a cross-linking agent as the microbial carrier, and the phosphorite thermal activation product is obtained by carrying out thermal activation, water quenching and grinding on phosphorite. A phosphorite thermal activation product obtained after phosphorite is subjected to thermal activation treatment has a porous structure, calcium, magnesium, silicon and slow-release phosphorus in the phosphorite thermal activation product are easily absorbed and utilized by functional microorganisms, a three-dimensional network porous structure is obtained after the phosphorite thermal activation product is cross-linked with a cross-linking agent, the loading rate of the functional microorganisms can be increased, and the utilization rate of the functional microorganisms is increased. In addition, good biocompatibility of the microbial carrier provides a suitable growth environment for functional microorganisms, survival and reproduction of the microorganisms in the gel are facilitated, and good application value and application effect are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial agents, and specifically to a microbial carrier and a preparation method thereof, a composite microbial agent and a preparation method and application thereof. Background Art

[0002] Chemical fertilizers provide the material foundation for the development of modern agricultural production and human food security. However, the low utilization rate of chemical fertilizers and the resulting high environmental risks continue to be a major problem plaguing the world. Microbial agents, as highly efficient and inexpensive ecological agents, can effectively reduce the use of pesticides and chemical fertilizers and are an important support for the sustainable development of ecological agriculture. However, current microbial agents are typically based on carriers such as diatomaceous earth, zeolite, bentonite, perlite, chitosan, chitin, and alginic acid. These carriers are costly, lack mineral nutrients, and have a low loading rate of functional microorganisms. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a microbial carrier and preparation method, a composite microbial agent and preparation method, and application.

[0004] The present invention solves the technical problem by adopting the following technical solutions.

[0005] The invention provides a microbial carrier. The microbial carrier is formed by cross-linking a thermally activated product of phosphate rock with a cross-linking agent. The thermally activated product of phosphate rock is obtained by thermally activating, water quenching and grinding the phosphate rock.

[0006] The present invention also provides a method for preparing the above-mentioned microbial carrier, which comprises: cross-linking a thermally activated product of phosphate rock and a cross-linking agent to form a microbial carrier.

[0007] The present invention also provides a composite microbial agent, comprising a microbial carrier and functional microorganisms loaded in the gel carrier, wherein the microbial carrier is prepared by the above-mentioned preparation method.

[0008] The present invention also provides a method for preparing the above-mentioned composite microbial agent, which comprises: cross-linking a thermally activated product of phosphate rock and a cross-linking agent to form a microbial carrier, and composite the microbial carrier with functional microorganisms to load the functional microorganisms on the microbial carrier to obtain a composite microbial agent.

[0009] The present invention also provides an application of the composite microbial agent or the composite microbial agent prepared by the above-mentioned preparation method in crop cultivation.

[0010] The present invention has the following beneficial effects:

[0011] The present invention provides a microbial carrier and a preparation method, a composite microbial agent and a preparation method, and an application. The microbial carrier provided by the present invention uses a cross-linked product formed by cross-linking a phosphate rock thermal activation product with a cross-linking agent as the microbial carrier, wherein the phosphate rock thermal activation product is obtained by thermally activating, water quenching, and grinding the phosphate rock. The porous structure of the phosphate rock thermal activation product after the phosphate rock is thermally activated can provide a shelter for functional microorganisms. On the other hand, after the phosphate rock is thermally activated, the calcium, magnesium, silicon, and slow-release phosphorus in the phosphate rock are easily absorbed and utilized by the functional microorganisms, providing rich nutrients for the functional microorganisms, increasing the mineral utilization rate and the number of microorganisms. After the above-mentioned microbial carrier is combined with the functional microorganisms, a composite microbial agent can be obtained. The composite microbial agent has the characteristics of the porous structure of the microbial carrier, rich nutrients, easy absorption, and high loading rate of functional microorganisms, realizing the functionalization of the carrier and high-value utilization of resources. The above-mentioned composite microbial agent is used in crop cultivation to improve soil, promote crop growth, enhance crop resistance, and improve the quality of agricultural products. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 This is an appearance diagram of the composite microbial agent provided in Example 1;

[0014] Figure 2 This is a photo of Chinese cabbage in the middle growth stage after application of the composite microbial agent provided in Example 1;

[0015] Figure 3 This is a photo of Chinese cabbage in the late growth stage after application of the composite microbial agent provided in Example 1;

[0016] Figure 4 This is a photo of Chinese cabbage at the harvest stage after application of the composite microbial agent provided in Example 1;

[0017] Figure 5 This is a photo of Chinese flowering cabbage during the sampling period after application of the composite microbial agent provided in Example 1. DETAILED DESCRIPTION

[0018] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0019] The following is a detailed description of a microbial carrier and its preparation method, a composite microbial agent and its preparation method, and its application provided in the embodiments of the present invention.

[0020] In a first aspect, an embodiment of the present invention provides a microbial carrier, which is formed by cross-linking a thermally activated product of phosphate rock with a cross-linking agent, and the thermally activated product of phosphate rock is obtained by thermally activating, water quenching and grinding phosphate rock.

[0021] Embodiments of the present invention provide a microbial carrier comprising a crosslinked product formed by crosslinking a thermally activated product of phosphate rock with a crosslinking agent. The thermally activated product is obtained by thermally activating, water quenching, and grinding phosphate rock. The porous structure of the thermally activated product provides a shelter for functional microorganisms, creating a favorable environment for their growth and reproduction. Furthermore, after thermal activation, the calcium, magnesium, silicon, and slow-release phosphorus in the phosphate rock are readily absorbed and utilized by the functional microorganisms, providing them with abundant nutrients and promoting their growth and reproduction. This not only improves mineral utilization but also increases the loading rate of the functional microorganisms loaded thereon.

[0022] In some optional embodiments, a three-dimensional porous gel formed by cross-linking a thermally activated product of phosphate rock with a cross-linking agent is used as a microbial carrier;

[0023] Preferably, the mass ratio of the thermally activated product of phosphate rock to the cross-linking agent is 97-99.5:3-0.5;

[0024] Preferably, the cross-linking agent is a natural polysaccharide, and the natural polysaccharide is selected from one or more of alginate, starch, carboxymethyl cellulose, and chitosan;

[0025] Preferably, the phosphate rock is medium-low grade phosphate rock, the temperature for thermal activation of the medium-low grade phosphate rock is 900-1200° C., the time is 25-45 min, and the particle size D90 after thermal activation, water quenching and grinding is ≤20 μm.

[0026] An embodiment of the present invention provides a microbial carrier, which uses a cross-linked product formed by cross-linking a thermally activated product of phosphate rock with a cross-linking agent as a microbial carrier, wherein the thermally activated product of phosphate rock is obtained by thermally activating, water quenching, and grinding medium- and low-grade phosphate rock (P2O5: 10-20%). Medium- and low-grade phosphate rock (P2O5: 10-20%) is often discarded due to its high impurities and low activation efficiency. However, medium- and low-grade phosphate rock contains nutrients such as phosphorus, silicon, calcium, and magnesium, which can promote the growth of crops. However, when it is used directly as a fertilizer, the ore composition is hard, the composition is complex, and the nutrient utilization rate is low, resulting in low added value of the product and low application level.

[0027] In order to effectively utilize medium and low-grade phosphate rock, the microbial carrier provided by the embodiment of the present invention can obtain a porous calcium-magnesium material after the phosphate rock, especially the medium and low-grade phosphate rock, is subjected to thermal activation treatment, water quenching and grinding. The porous calcium-magnesium material is cross-linked with a cross-linking agent to obtain a microbial carrier with a reticular porous structure. The reticular porous structure can provide a shelter for functional microorganisms, and the large amount of slow-release phosphorus, calcium, and magnesium elements contained in the thermal activation product of the phosphate rock are easy to be absorbed and utilized by functional microorganisms, promoting the growth and reproduction of microorganisms. Loading functional microorganisms thereon can play a role in improving soil, promoting crop growth, improving crop resistance, and improving the quality of agricultural products. As can be seen from the above, the above-mentioned microbial carrier provided by the present invention can not only solve the outlet problem of mineral elements such as silicon, calcium, and magnesium in medium and low-grade phosphate rock, maximize the comprehensive utilization value of phosphate rock, but also improve the loading rate and stability of the functional microorganisms loaded thereon.

[0028] In a second aspect, an embodiment of the present invention provides a method for preparing the above-mentioned microbial carrier, which comprises: cross-linking a thermally activated product of phosphate rock and a cross-linking agent to form a microbial carrier.

[0029] In some optional embodiments, the process comprises the following steps: using medium- and low-grade phosphate rock as raw material, subjecting the phosphate rock to thermal activation, water quenching, and grinding to obtain a porous calcium-magnesium slurry; adjusting the pH of the porous calcium-magnesium slurry; and mixing and cross-linking the slurry with a natural polysaccharide to obtain a microbial carrier;

[0030] Preferably, the preparation of the porous calcium magnesium slurry comprises: treating phosphate rock at 900-1200° C. for 25-45 min, followed by water quenching and nano-grinding to obtain a porous calcium magnesium slurry having a pH of 9-11 and a particle size D90 ≤ 20 μm;

[0031] Preferably, the preparation of the microbial carrier includes: adjusting the pH of the porous calcium magnesium slurry to 5.5-7.5 with 2-5wt% citric acid, and then adding 1-5% of the amount of natural polysaccharide used in the porous calcium magnesium slurry for mixing and cross-linking to obtain the microbial carrier.

[0032] An embodiment of the present invention provides a method for preparing the above-mentioned microbial carrier, which comprises: treating phosphate rock to obtain a porous calcium-magnesium slurry, adjusting the pH, and then mixing and cross-linking with natural polysaccharides to enhance the porosity and obtain a gel solution with a three-dimensional porous gel network structure. The high water content and porosity of the gel solution make it easier for functional microorganisms to be adsorbed and encapsulated, thereby improving the loading efficiency. This characteristic enables the microorganisms to be more evenly distributed in the gel, avoiding the aggregation and precipitation of functional microorganisms, and the gel solution usually has good biocompatibility and can be combined with structural properties similar to the extracellular matrix to provide a suitable growth environment for microorganisms. This biocompatibility helps the functional microorganisms survive and reproduce in the gel, thereby extending their service life. By adjusting the cross-linking degree, porosity and swelling properties of the gel, the release rate and mode of the microorganisms can also be controlled. This controlled release characteristic enables the microorganisms to be gradually released when needed, achieving the purpose of slow release and synergistic effect.

[0033] In a third aspect, an embodiment of the present invention provides a composite microbial agent, comprising a microbial carrier and functional microorganisms loaded on the microbial carrier, wherein the microbial carrier is prepared using the above-mentioned preparation method.

[0034] In some optional embodiments, the functional microorganisms include one or more of Bacillus licheniformis, Bacillus velezinsis, and Bacillus subtilis;

[0035] Preferably, the functional microorganisms include: Bacillus licheniformis, Bacillus velez and Bacillus subtilis in a mass ratio of 1-3:1-3:1-3;

[0036] Preferably, the deposit number of Bacillus licheniformis is CGMCC NO.24738, the deposit number of Bacillus velez is CGMCC NO.20317, and the deposit number of Bacillus subtilis is CGMCC NO.26398.

[0037] An embodiment of the present invention provides a composite microbial agent, including a microbial carrier and functional microorganisms loaded in a gel carrier, wherein the microbial agent can be one or more of Bacillus licheniformis, Bacillus Velez-like bacteria, and Bacillus subtilis. More preferably, Bacillus licheniformis, Bacillus Velez-like bacteria, and Bacillus subtilis are used in combination. This composite bacterial species has the efficacy of decomposing mineral phosphorus, inhibiting soil-borne crop diseases, and increasing crop yields.

[0038] In some optional embodiments, the total viable count of the composite microbial agent is 2×10 8 -10×10 9 CFU / g.

[0039] In a fourth aspect, an embodiment of the present invention provides a method for preparing the above-mentioned composite microbial agent, which includes: cross-linking the thermal activation product of phosphate rock and a cross-linking agent to form a microbial carrier, and compounding the microbial carrier and functional microorganisms to load functional microorganisms on the microbial carrier to obtain a composite microbial agent.

[0040] In some optional embodiments, the steps include: using medium and low grade phosphate rock as raw material, subjecting the raw material to thermal activation, water quenching and grinding to obtain porous calcium magnesium slurry, adjusting the pH of the porous calcium magnesium slurry, mixing and cross-linking with natural polysaccharides to obtain a microbial carrier, and then mixing the microbial carrier with a bacterial solution of functional microorganisms and drying and forming the mixture to obtain a composite microbial agent.

[0041] Preferably, mixing the microbial carrier with the bacterial solution of the functional microorganism comprises: culturing Bacillus licheniformis, Bacillus velezensis and Bacillus subtilis respectively until the number of viable bacteria is ≥ 1×10 9 CFU / mL, obtain the bacterial solution of each functional microorganism cultured separately, take one or several bacterial solutions cultured separately as the bacterial solution of the functional microorganism, mix them according to the mass ratio of microbial carrier and functional microorganism solution of 5-3:3-1, and shake and adsorb at 35-45℃ for 18-24h to promote the combination of the two;

[0042] Preferably, the powder is prepared by spray drying, wherein the air inlet temperature during the spray drying process is 75-85°C and the outlet temperature is 35-45°C.

[0043] An embodiment of the present invention provides a method for preparing the above-mentioned composite microbial agent, which includes: processing medium and low-grade phosphate rock to obtain porous calcium-magnesium slurry, adjusting the pH, mixing and cross-linking with natural polysaccharides to obtain a gel liquid with a three-dimensional porous gel network structure, and then mixing the gel liquid with the bacterial liquid to promote the composite of the two, and then drying and molding to obtain a composite microbial powder. On the one hand, the rich pore structure in the gel liquid can increase the loading rate of functional microorganisms. On the other hand, the water and solute molecules absorbed and retained in the gel liquid are in a swollen state, which can promote the activity of microorganisms and improve the survival rate of the microbial agent, thereby making the microorganisms have good room temperature storage properties.

[0044] In a fifth aspect, an embodiment of the present invention provides an application of the above-mentioned composite microbial agent or the composite microbial agent prepared by the above-mentioned preparation method in crop cultivation.

[0045] The present invention will be further described below with reference to the embodiments.

[0046] Example 1:

[0047] 1. Take low- to medium-grade phosphate rock (P2O5: 12%, CaO: 28%, MgO: 2.3%, SiO2: 3.8%), crush it, activate it in a rotary kiln at 1100°C for 30 minutes, quench it with water, and ball-mill it to D90 = 18μm to obtain a porous calcium-magnesium slurry;

[0048] 2. The porous calcium magnesium slurry was adjusted to pH 7.0 with 3% citric acid, and sodium alginate was added in an amount of 1% by weight of the total weight of the porous calcium magnesium slurry to obtain a mixed slurry;

[0049] 3. Combine Bacillus licheniformis, Bacillus velezensis, and Bacillus subtilis in a ratio of 1:2:1, with a viable cell count of 3×10 9 CFU / mL;

[0050] 4. Mix the mixed slurry with the composite bacterial agent and spray dry to obtain powder. After testing, the number of viable bacteria in the powder is ≥2×10 8 CFU / g, the appearance of the composite microbial agent can be found in Figure 1 .

[0051] Example 2:

[0052] The difference from Example 1 is that Bacillus licheniformis: Bacillus velezensis: Bacillus subtilis are compounded in a ratio of 1:1:1, and the number of viable bacteria is 3×10 9 CFU / mL.

[0053] Example 3:

[0054] The difference from Example 1 is that Bacillus licheniformis: Bacillus velezensis: Bacillus subtilis are compounded in a ratio of 1:3:1, and the number of viable bacteria is 3×10 9 CFU / mL.

[0055] Comparative Example 1:

[0056] The difference from Example 1 is that the low- and medium-grade phosphate rock is not processed:

[0057] 1. Take medium and low grade phosphate rock (P2O5: 12%, CaO: 28%, MgO: 2.3%, SiO2: 3.8%) and perform crushing, water quenching and ball milling;

[0058] 2. Adjust the pH to 7.0 with 3% citric acid and add 1% sodium alginate to obtain a mixed slurry;

[0059] 3. Combine Bacillus licheniformis, Bacillus velezensis, and Bacillus subtilis in a ratio of 1:2:1, with a viable cell count of 3×10 9 CFU / mL;

[0060] 4. Mix the mixed slurry with the composite bacterial solution and spray dry to obtain powder. The number of viable bacteria is ≥ 0.5×10 8 CFU / g.

[0061] Comparative Example 2:

[0062] The difference from Example 1 is that the low-grade phosphate rock is replaced with peat and bentonite:

[0063] 1. Take peat (organic matter content ≥ 50%) and bentonite and mix them evenly, with the peat added in an amount of 80% and the bentonite added in an amount of 20%;

[0064] 2. Adjust the pH of the material to 7.0 with 3% citric acid, add peat and bentonite at 1% sodium alginate;

[0065] 3. Combine Bacillus licheniformis, Bacillus velezensis, and Bacillus subtilis in a ratio of 1:2:1, with a viable cell count of 3×10 9 CFU / mL;

[0066] 4. Mix the material and bacterial solution, spray dry to obtain powder, the number of viable bacteria ≥ 2×10 8 CFU / g.

[0067] Comparative Example 3:

[0068] The difference from Example 1 is that the low-grade phosphate rock is replaced with peat and bentonite:

[0069] 1. Take peat (organic matter content ≥ 50%) and bentonite and mix them evenly, with the peat added in an amount of 90% and the bentonite added in an amount of 10%;

[0070] 2. Adjust the pH of the material to 7.0 with 3% citric acid, add peat and bentonite at 1% sodium alginate;

[0071] 3. Combine Bacillus licheniformis, Bacillus velezensis, and Bacillus subtilis in a ratio of 1:2:1, with a viable cell count of 3×10 9 CFU / mL;

[0072] 4. Mix the material and bacterial solution, spray dry to obtain powder, the number of viable bacteria ≥ 2×10 8 CFU / g.

[0073] Test Example 1-Load Effect Test:

[0074] The effective viable bacterial counts in the bacterial agents prepared in Example 1 and Comparative Examples 1-3 were detected respectively. 50 g of uniform samples were prepared, 1 g of the bacterial agents prepared in Example 1 and Comparative Examples 1-3 were weighed and placed in sterile physiological saline and shaken thoroughly. The sample was pipetted using a pipette and diluted 10 times. After dilution 5 times, 0.1 ml of the diluted liquid was pipetted using a pipette and evenly applied to the culture medium. The viable bacterial count was detected by the plate count method, as shown in Table 1.

[0075] Table 1

[0076]

[0077] As can be seen from Table 1, the effective viable bacteria counts of the bacterial agent prepared in Example 1 are greater than those in Comparative Examples 1-3. This is because the present invention uses a porous carrier of calcium magnesium slurry after phosphate rock treatment to load the composite microorganisms, and then uses sodium alginate and calcium ions (Ca 2+ ) cross-linked to form a three-dimensional porous gel network, which can attach and load the composite microorganisms. Citric acid preferentially chelates the free Ca in the slurry. 2+ / Mg 2+ , slowing down the gelation rate of sodium alginate, avoiding local over-crosslinking, forming more uniform pores, and increasing the loading rate of composite microorganisms.

[0078] After the microbial agents prepared in Example 1 and Comparative Examples 1-3 were stored at room temperature for 90 days, the number of effective viable bacteria in the microbial agents was detected. The specific results are shown in Table 2.

[0079] Table 2

[0080]

[0081] As can be seen from Table 2, after 90 days of storage at room temperature, the effective viable bacterial survival rate of the bacterial agent in Example 1 can still reach more than 90%, while the bacterial agent without calcium magnesium slurry porous carrier loading, such as Comparative Example 1, has an effective viable bacterial survival rate of about 50%. It can be seen that the calcium magnesium slurry porous carrier loading, and then the sodium alginate and calcium ion (Ca 2+ ) are cross-linked to form a three-dimensional porous gel network, and the water and solute molecules absorbed and retained in the hydrogel are in a swollen state, which promotes the activity of the composite microbial bacteria and improves the survival rate of the composite microbial bacteria, so that the composite microbial bacteria has good room temperature storage properties; while the survival rate of the effective live bacteria loaded with peat and bentonite in Comparative Examples 2 and 3 is about 60%.

[0082] Test Example 2 - Yield-increasing effect test:

[0083] Test location: Hongguang Village, Pingtan Town, Huiyang District, Huizhou City, Guangdong Province

[0084] Experimental crops: Chinese cabbage

[0085] Test materials: microbial agents prepared in Example 1, Example 2 and Comparative Example 1, Comparative Example 2, and Comparative Example 3, and compound fertilizer 15-15-15;

[0086] The experiment set up 6 treatments, each with 3 replicates, in randomized block arrangement, with a plot area of ​​20m. The design of each treatment is as follows:

[0087] Treatment 1: 40 kg of conventional fertilizer (compound fertilizer 15-15-15) + 50 kg of "microbial agent of Example 1" per mu as base fertilizer;

[0088] Treatment 2: 40 kg of conventional fertilizer (compound fertilizer 15-15-15) + 50 kg of "microbial agent of Example 2" per mu as base fertilizer;

[0089] Treatment 3: 40 kg of conventional fertilizer (compound fertilizer 15-15-15) + 50 kg of "Comparative Example 1 microbial agent" per mu as base fertilizer;

[0090] Treatment 4: 40 kg of conventional fertilizer (compound fertilizer 15-15-15) + 50 kg of "Comparative Example 2 microbial agent" per mu as base fertilizer;

[0091] Treatment 5: 40 kg of conventional fertilizer (compound fertilizer 15-15-15) + 50 kg of "Comparative Example 3 microbial agent" per mu as base fertilizer;

[0092] Treatment 6: conventional control, 40 kg of customary fertilizer (compound fertilizer 15-15-15);

[0093] The basic seedlings per mu of Chinese cabbage are about 41,600 plants. The period from sowing to harvest is 32 days. The main agronomic characteristics of Chinese cabbage at harvest are as follows (Table 3):

[0094] Table 3

[0095] deal with Plant height (cm) Stem diameter (mm) Taproot length (cm) Single tree weight (g) one 30.2 13.6 6.8 34.4 two 29.5 13.5 6.7 33.8 three 27.8 12.5 6.2 32.0 Four 28.0 12.8 6.3 32.3 five 28.5 12.7 6.5 32.8 six 27.3 12.4 6.0 31.3

[0096] As can be seen from Table 3, the plant height, stem diameter, taproot length and single plant weight of treatment one of the application of "Agricultural microbial agent of Example 1" increased by 2.4%, 0.7%, 1.5% and 1.7% respectively compared with those of treatment two, and increased by 8.6%, 8.8%, 9.6% and 7.5% respectively compared with those of treatment three; increased by 7.8%, 6.2%, 7.9% and 6.5% respectively compared with those of treatment four; increased by 5.9%, 7.0%, 4.6% and 4.8% respectively compared with those of treatment five; and increased by 10.6%, 9.6%, 13.3% and 9.9% respectively compared with those of treatment six. The results showed that applying 50 kg of the microbial agent of Example 1 as base fertilizer per mu during the planting of Chinese cabbage could effectively promote the growth of Chinese cabbage compared with treatments 3, 4, 5 and 6, and had a better promoting effect on increasing the plant height, stem diameter, taproot length and single plant weight of Chinese cabbage (the growth of Chinese cabbage at different stages after applying the composite microbial agent provided in Example 1 is shown in Figure 2). Figure 2-5 ).

[0097] Table 4

[0098]

[0099] As can be seen from Table 4, the average yield of the Chinese cabbage plot in treatment one was the highest, followed by treatment two. The yields of treatments one and two were significantly higher than those of treatments three, four, five, and six. The average yield of the Chinese cabbage plot in treatment one, which was applied with the "microbial agent of Example 1", was 42.9 kg, equivalent to 1430.7 kg per mu, an increase of 76.7 kg per mu over treatment three, an increase of 5.7%, an increase of 116.7 kg per mu over treatment four, an increase of 8.9%, an increase of 103.4 kg per mu over treatment five, an increase of 7.8%, and an increase of 133.4 kg per mu over treatment six, an increase of 10.2%. The average yield of the two Chinese cabbage plots in which the "microbial agent of Example 2" was applied was 42.5 kg, equivalent to an yield of 1417.3 kg per mu, an increase of 63.3 kg over the three mu treatment, an increase of 4.7%, an increase of 103.3 kg over the four mu treatment, an increase of 7.9%, an increase of 90 kg over the five mu treatment, an increase of 6.8%; and an increase of 120 kg over the six treatment, an increase of 9.2%. The results show that applying 50 kg of the "microbial agent of Example 1" and the "microbial agent of Example 1" as base fertilizer per mu in Chinese cabbage cultivation has a good yield-increasing effect, and its yield-increasing effect is significantly better than applying the "microbial agent of Comparative Example 1", "microbial agent of Comparative Example 2", and "microbial agent of Comparative Example 3".

[0100] Test Example 3-Disease resistance test:

[0101] Test location: Ames test greenhouse potted plants in Pinggu District, Beijing

[0102] Test crop: Tomato

[0103] Test materials: microbial agents prepared using the methods of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, and compound fertilizer 15-15-15;

[0104] The experiment consisted of five treatments, arranged in randomized blocks, with 27 plants per treatment. Tomato plants were inoculated with tomato wilt and then planted. The treatment designs were as follows:

[0105] Treatment 1: conventional fertilization, base fertilizer application of compound fertilizer 15-15-15, 40 kg per mu;

[0106] Treatment 2: Base fertilizer application: 80 kg of bacterial fertilizer from Example 1 per mu, plus 40 kg of compound fertilizer 15-15-15;

[0107] Treatment 3: Base fertilizer application: 80 kg of bacterial fertilizer per mu according to comparative example 1, plus 40 kg of compound fertilizer 15-15-15;

[0108] Treatment 4: Base fertilizer application: 80 kg of bacterial fertilizer from Comparative Example 2 per mu, plus 40 kg of compound fertilizer 15-15-15;

[0109] Treatment 5: Base fertilizer application: 80 kg of comparative example 3 bacterial fertilizer per mu, plus 40 kg of compound fertilizer 15-15-15;

[0110] Treatment 6: Base fertilizer application: 80 kg / mu of the bacterial fertilizer of comparative example 4, plus 40 kg of compound fertilizer 15-15-15;

[0111] From the time the tomato seedlings were infected to the end of the experiment, the infection status of each treatment group is as shown in Table 5:

[0112] Table 5

[0113] deal with Number of cases (strains) Incidence (%) Prevention effect (%) Processing 1 24 88.88 — Process 2 6 22.22 75 Processing Three 16 59.25 32 Processing Four 13 48.15 45.82 Processing Five 10.8 40.00 55 Processing six 10 37.03 58.3

[0114] Note: Incidence rate = number of cases / total number of tests × 100%

[0115] Preventive effect (%) = (incidence rate of blank group - incidence rate of treated group) / incidence rate of blank group) × 100%.

[0116] The test results in Table 5 show that after inoculation with tomato wilt, the control efficacy of Treatment 2 (the inoculum of Example 1) was 75%, while the control efficacy of Treatment 3 (the inoculum of Comparative Example 1), Treatment 4 (the inoculum of Comparative Example 2), and Treatment 5 (the inoculum of Comparative Example 3) were 32%, 45.82%, and 55%, respectively. The control efficacy of Treatment 2, which was treated with the inoculum of Example 1, was increased by 43%, 29.18%, and 20%, respectively, compared to Treatments 3, 4, and 5, indicating that the microbial inoculum prepared by the method of Example 1 has a better disease control effect.

[0117] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A microbial carrier, characterized in that The microbial carrier is formed by cross-linking a thermally activated product of phosphate rock with a cross-linking agent, and the thermally activated product of phosphate rock is obtained by thermally activating, water quenching and grinding phosphate rock.

2. The microbial carrier according to claim 1, characterized in that The three-dimensional porous gel formed by cross-linking the thermally activated product of the phosphate rock with the cross-linking agent is used as a microbial carrier; Preferably, the mass ratio of the phosphate rock thermal activation product to the cross-linking agent is 97-99.5:3-0.5; Preferably, the cross-linking agent is a natural polysaccharide, and the natural polysaccharide is selected from one or more of alginate, starch, carboxymethyl cellulose, and chitosan; Preferably, the phosphate rock is a medium-low grade phosphate rock, the temperature of the thermal activation of the medium-low grade phosphate rock is 900-1200° C., the time is 25-45 minutes, and the particle size D90 after thermal activation, water quenching and grinding is ≤20 μm.

3. A method for preparing a microbial carrier according to claim 1 or 2, characterized in that: It includes: The phosphate rock thermal activation product and a cross-linking agent are cross-linked to form the microbial carrier.

4. The preparation method according to claim 3, characterized in that The following steps are involved: Using low- and medium-grade phosphate rock as raw material, the raw material is subjected to thermal activation, water quenching, and grinding to obtain a porous calcium-magnesium slurry. After adjusting the pH of the porous calcium-magnesium slurry, the slurry is mixed and cross-linked with the natural polysaccharide to obtain the microbial carrier; Preferably, the preparation of the porous calcium magnesium slurry comprises: treating phosphate rock at 900-1200° C. for 25-45 min, followed by water quenching and nano-grinding to obtain a porous calcium magnesium slurry having a pH of 9-11 and a particle size D90 ≤ 20 μm; Preferably, the preparation of the microbial carrier includes: adjusting the pH of the porous calcium magnesium slurry to 5.5-7.5 with 2-5wt% citric acid, and then adding 1-5% natural polysaccharide of the porous calcium magnesium slurry for mixing and cross-linking to obtain the microbial carrier.

5. A composite microbial agent, characterized in that: It comprises a microbial carrier and functional microorganisms loaded on a gel carrier, wherein the microbial carrier is the microbial carrier according to claim 1 or 2.

6. The composite microbial agent according to claim 5, characterized in that The functional microorganisms include one or more of Bacillus licheniformis, Bacillus velez and Bacillus subtilis; Preferably, the functional microorganisms include: Bacillus licheniformis, Bacillus velez and Bacillus subtilis in a mass ratio of 1-3:1-3:1-3; Preferably, the deposit number of the Bacillus licheniformis is CGMCC NO.24738, the deposit number of the Bacillus velez is CGMCC NO.20317, and the deposit number of the Bacillus subtilis is CGMCC NO.26398.

7. The composite microbial agent according to claim 5 or 6, characterized in that The total viable count of the composite microbial agent is 2×10 8 -10×10 9 CFU / g.

8. A method for preparing the composite microbial agent according to any one of claims 5 to 7, characterized in that: It includes: The phosphate rock thermal activation product and a cross-linking agent are cross-linked to form the microbial carrier, and the microbial carrier and functional microorganisms are composited to load the functional microorganisms on the microbial carrier to obtain the composite microbial agent.

9. The preparation method according to claim 8, characterized in that The following steps are involved: Using low- and medium-grade phosphate rock as raw material, the raw material is subjected to heat activation, water quenching, and grinding to obtain a porous calcium-magnesium slurry. After the pH of the porous calcium-magnesium slurry is adjusted, it is mixed and cross-linked with the natural polysaccharide to obtain a microbial carrier. The microbial carrier is then mixed with a bacterial solution of functional microorganisms and dried to form a composite microbial agent. Preferably, mixing the microbial carrier with the bacterial solution of the functional microorganism comprises: culturing Bacillus licheniformis, Bacillus velezensis and Bacillus subtilis respectively until the number of viable bacteria is ≥ 1×10 9 CFU / mL, obtain the bacterial liquid of each functional microorganism cultured separately, take one or several bacterial liquids cultured separately as the bacterial liquid of the functional microorganism, mix the microbial carrier and the bacterial liquid of the functional microorganism in a mass ratio of 5-3:3-1, and adsorb at 35-45°C with shaking for 18-24h to promote the recombination of the two; Preferably, the drying and forming method is a spray drying method, wherein the air inlet temperature during the spray drying process is 75-85°C and the outlet temperature is 35-45°C.

10. Use of the composite microbial agent according to any one of claims 5 to 7 or the composite microbial agent prepared by the preparation method according to any one of claims 8 to 9 in crop cultivation.

Images