Straw in-situ decomposition complex microbial inoculant, field application method and use thereof

Abstract

The application discloses a straw in-situ decomposition compound microbial inoculum, a field application method and application thereof, and belongs to the technical field of agricultural microorganisms. 9 The effective viable cell count of the compound microbial inoculum is greater than or equal to 5.0x10 9 Cfu / g, and the compound microbial inoculum comprises Stenotrophomonas maltophilia JGDQ29-2, Weissella doderleinii zqw76, Neurospora crassa N7 and Aspergillus terreus 10-80. When the compound microbial inoculum prepared by the application is applied to straw in-situ, the decomposition efficiency is excellent, the degradation rate of the straw can be significantly improved, the soil fertility is improved, and the yield of crops is effectively promoted. In addition, the application also provides a standardized application procedure for the compound microbial inoculum, and forms an efficient, stable and operable straw in-situ decomposition solution.

Description

Technical Field

[0001] This invention belongs to the field of agricultural microbial technology, specifically relating to a compound microbial agent for in-situ decomposition of straw, its field application method, and its uses. Background Technology

[0002] Returning straw to the field is an important measure to improve soil fertility, enhance soil structure, and achieve sustainable agricultural development. Currently, using microbial agents to accelerate straw decomposition has become the mainstream technical approach. However, most microbial agents are only suitable for straw composting, which is complex to operate, costly, and difficult to promote. Direct in-situ straw return is an important way to utilize straw resources; however, straw contains high levels of recalcitrant components such as cellulose, hemicellulose, and lignin, resulting in a long natural decomposition cycle that directly affects the sowing and growth of subsequent crops. Especially in the low-temperature regions of Northeast China, the low-temperature environment further restricts the decomposition efficiency of straw.

[0003] Currently, there are few microbial agents suitable for in-situ straw return to farmland in the low-temperature environment of Northeast China. Commercially available decomposing agents are mostly composed of cellulose-decomposing bacteria, which can accelerate straw crushing to some extent under suitable conditions, but suffer from problems such as limited bacterial function, low decomposition efficiency, poor environmental adaptability, and low degradation efficiency under low-temperature conditions. Furthermore, the lack of standardized procedures for field application, including inconsistent timing, dosage, and mixing methods with straw and soil, leads to low agent survival rates and unstable decomposition effects.

[0004] Therefore, there is an urgent need to develop a compound microbial agent for in-situ decomposition of straw with a reasonable strain composition, strong synergistic effect, high decomposition efficiency, and standardized field application procedures. Summary of the Invention

[0005] To address the aforementioned shortcomings in the existing technology, this invention provides a straw in-situ decomposition compound microbial agent, its field application method, and its uses.

[0006] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows: The purpose of this invention is to provide a compound microbial agent for in-situ decomposition of straw, wherein the effective viable bacteria count in the compound microbial agent is ≥5.0×10⁻⁶. 9 cfu / g, which includes: Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia JGDQ29-2, with accession number CGMCC No. 27979, was deposited at the China General Microbiological Culture Collection Center on July 24, 2023; Weissella esculenta ( Weissella cibaria zqw76, with accession number CGMCC No. 25147, was deposited at the China General Microbiological Culture Collection Center on June 21, 2022. Neurospora crassa ( Neurospora crassa N7, with accession number CGMCC No. 40738, was deposited at the China General Microbiological Culture Collection Center on July 24, 2023. Aspergillus terreus ( Aspergillus terreus )10-80, with accession number CGMCC No. 41616, was deposited at the China General Microbiological Culture Collection Center on November 6, 2024.

[0007] Furthermore, the effective viable count of Stenotrophomonas maltophilia JGDQ29-2 in the compound microbial agent is 10-50%; the effective viable count of Weissella maltophilia zqw76 is 10-65%; the effective viable count of Neurospora crassa N7 is 15-55%; and the effective viable count of Aspergillus terreus 10-80 is 10-65%.

[0008] Furthermore, the effective viable count of Stenotrophomonas maltophilia JGDQ29-2 in the compound microbial agent is 25-35%; the effective viable count of Weissella maltophilia zqw76 is 20-30%; the effective viable count of Neurospora crassa N7 is 25-35%; and the effective viable count of Aspergillus terreus 10-80 is 15-25%.

[0009] Furthermore, the effective viable count of Stenotrophomonas maltophilia JGDQ29-2 was 25%; the effective viable count of Weissella maltophilia zqw76 was 30%; the effective viable count of Neurospora crassa N7 was 25%; and the effective viable count of Aspergillus terreus 10-80 was 20%.

[0010] Another object of the present invention is to provide a method for preparing the above-mentioned straw in-situ decomposition compound microbial agent, comprising the following steps: (1) Stenotrophomonas maltophilia JGDQ29-2 was inoculated into LB liquid medium and cultured at 30-35℃ with shaking for 16-24 h; (2) Inoculate Weissella esculenta zqw76 into MRS liquid medium and incubate at 35-40℃ for 16-24h. (3) Inoculate Neurospora crassa N7 and Aspergillus terreus 10-80 into PDA liquid medium and culture at 25-30℃ with shaking for 68-74h; (4) Mix the various microbial agents according to the proportion of live bacteria in the formula to obtain the compound microbial agent.

[0011] Another object of the present invention is to provide the use of the above-mentioned straw in-situ decomposition compound microbial agent in the preparation of straw return-to-field formulations.

[0012] Another object of the present invention is to provide the use of the above-mentioned straw in-situ decomposition compound microbial agent in the preparation of formulations that improve soil fertility.

[0013] Another object of the present invention is to provide the use of the above-mentioned straw in-situ decomposition compound microbial agent in the preparation of formulations that enhance crop yield.

[0014] Furthermore, the crops are rice, corn, or soybeans.

[0015] Furthermore, the formulation is a nitrogen-reducing fertilizer, in which the compound microbial agent replaces 20-25% of the nitrogen fertilizer in the fertilizer, thus forming a nitrogen-reducing fertilizer.

[0016] Another objective of this invention is to provide a method for field application of a compound microbial agent for in-situ decomposition of straw, comprising the following steps: (1) Straw treatment Crush the straw to a length of ≤15 cm, spread it evenly on the field surface, and then perform rotary tillage on the crushed straw so that it is 15~20 cm below the surface. (2) Preparation of microbial agents Mix the compound microbial agent with the soil at a mass ratio of 1:10~15 to form a microbial agent-soil mixture. Alternatively, the bacterial agent can be prepared into a bacterial suspension for later use; (3) Application Apply the bacterial suspension or bacterial agent-soil mixture to the field treated in step (1) by spraying or spreading, and then cultivate it to a depth of 15-20 cm to fully mix it with straw and soil. (4) Water management Irrigate or utilize natural rainfall within 24 hours after application to bring the soil moisture content of the 0-20 cm layer to 60%-70% of field capacity, thereby promoting the activation of the microbial agent and the water absorption and swelling of the straw.

[0017] The beneficial effects of this invention are: The compound microbial agent prepared by this invention exhibits excellent decomposition efficiency when applied to in-situ straw return to the field, significantly improving straw degradation rate, enhancing soil fertility, and effectively promoting crop yield increase. Furthermore, this invention provides a standardized application procedure for this compound microbial agent, forming a highly efficient, stable, and operable solution for in-situ straw decomposition. Attached Figure Description

[0018] Figure 1 The image shows the decomposition of straw after applying the straw in-situ decomposition compound microbial agent prepared in Example 1. Detailed Implementation

[0019] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0020] Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia JGDQ29-2, with accession number CGMCC No. 27979, was deposited at the China General Microbiological Culture Collection Center on July 24, 2023, and has been disclosed in the invention patent application with application number CN202411674934.3.

[0021] Weissella esculenta ( Weissella cibaria zqw76, with accession number CGMCC No.25147, was deposited at the China General Microbiological Culture Collection Center on June 21, 2022. It has been disclosed in the invention patent application CN202310684058.1.

[0022] Neurospora crassa ( Neurospora crassa N7, with accession number CGMCC No. 40738, was deposited at the China General Microbiological Culture Collection Center on July 24, 2023, and has been disclosed in invention patent application number CN202411675478.4. Aspergillus terreus ( Aspergillus terreus )10-80, with accession number CGMCC No.41616, was deposited at the China General Microbiological Culture Collection Center on November 6, 2024.

[0023] Example 1 A compound microbial agent for in-situ decomposition of straw, wherein Stenotrophomonas maltophilia JGDQ29-2 has an effective viable count of 25%; Weissella maltophilia zqw76 has an effective viable count of 30%; Neurospora crassa N7 has an effective viable count of 25%; and Aspergillus terreus 10-80 has an effective viable count of 20%.

[0024] The preparation method is as follows: (1) Stenotrophomonas maltophilia JGDQ29-2 was inoculated into LB liquid medium and cultured at 30℃ and 180r / min for 16~24h with shaking. (2) Inoculate Weissella esculenta zqw76 into MRS liquid medium and incubate at 37°C for 16-24 h. (3) Inoculate Neurospora crassa N7 and Aspergillus terreus 10-80 into PDA liquid medium and culture at 28℃ and 150r / min for 68-74h. (4) Mix the various inoculants according to the proportion of viable bacteria in the formula to obtain a solution with a pH of 7.0 and a total effective viable bacteria count of 5.6 × 10⁻⁶. 9 A compound microbial agent with cfu / g.

[0025] Example 2 A compound microbial agent for in-situ decomposition of straw, wherein Stenotrophomonas maltophilia JGDQ29-2 has an effective viable count of 30%; Weissella maltophilia zqw76 has an effective viable count of 20%; Neurospora crassa N7 has an effective viable count of 30%; and Aspergillus terreus 10-80 has an effective viable count of 20%.

[0026] The preparation method is as follows: (1) Stenotrophomonas maltophilia JGDQ29-2 was inoculated into LB liquid medium and cultured at 30℃ and 180r / min for 16~24h with shaking. (2) Inoculate Weissella esculenta zqw76 into MRS liquid medium and incubate at 37°C for 16-24 h. (3) Inoculate Neurospora crassa N7 and Aspergillus terreus 10-80 into PDA liquid medium and culture at 28℃ and 150r / min for 68-74h. (4) Mix the various inoculants according to the proportion of viable bacteria in the formula to obtain a solution with a pH of 7.0 and a total effective viable bacteria count of 6.4 × 10⁻⁶. 9 A compound microbial agent with cfu / g.

[0027] Example 3 A compound microbial agent for in-situ decomposition of straw, wherein Stenotrophomonas maltophilia JGDQ29-2 has an effective viable count of 28%; Weissella stolonifera zqw76 has an effective viable count of 22%; Neurospora crassa N7 has an effective viable count of 32%; and Aspergillus terreus 10-80 has an effective viable count of 18%.

[0028] The preparation method is as follows: (1) Stenotrophomonas maltophilia JGDQ29-2 was inoculated into LB liquid medium and cultured at 30℃ and 180r / min for 16~24h with shaking. (2) Inoculate Weissella esculenta zqw76 into MRS liquid medium and incubate at 37°C for 16-24 h. (3) Inoculate Neurospora crassa N7 and Aspergillus terreus 10-80 into PDA liquid medium and culture at 28℃ and 150r / min for 68-74h. (4) Mix the various inoculants according to the proportion of viable bacteria in the formula to obtain a solution with a pH of 7.0 and a total effective viable bacteria count of 5.8 × 10⁻⁶. 9 A compound microbial agent with cfu / g.

[0029] Example 4 A compound microbial agent for in-situ decomposition of straw, wherein Stenotrophomonas maltophilia JGDQ29-2 has an effective viable count of 10%; Weissella maltophilia zqw76 has an effective viable count of 15%; Neurospora crassa N7 has an effective viable count of 10%; and Aspergillus terreus 10-80 has an effective viable count of 65%.

[0030] The preparation method is as follows: (1) Stenotrophomonas maltophilia JGDQ29-2 was inoculated into LB liquid medium and cultured at 30℃ and 180r / min for 16~24h with shaking. (2) Inoculate Weissella esculenta zqw76 into MRS liquid medium and incubate at 37°C for 16-24 h. (3) Inoculate Neurospora crassa N7 and Aspergillus terreus 10-80 into PDA liquid medium and culture at 28℃ and 150r / min for 68-74h. (4) Mix the various inoculants according to the proportion of viable bacteria in the formula to obtain a solution with a pH of 7.0 and a total effective viable bacteria count of 5.8 × 10⁻⁶. 9 A compound microbial agent with cfu / g.

[0031] Example 5 The specific procedures for applying the above-mentioned compound microbial agent in the field are as follows: (1) Straw treatment When harvesting crops, combine harvesters equipped with straw crushing devices are used to crush the straw to a length of ≤15 cm, and then spread it evenly on the field surface. After crushing, the straw is rotary tilled to a depth of 15~20 cm from the ground surface.

[0032] (2) Preparation of microbial agents The application rate of bacterial agent per acre is 3.75 × 10⁶ bacteria. 12 CFU, fungi 3.75×10 11 For the dosage of spores, mix the inoculum with moist fine soil or sand at a mass ratio of 1:10-15 to prepare an inoculum-soil mixture; or use the water-soluble activation method, dissolve 1 kg of inoculum powder in 50 L of water, stir for 30 min to form an inoculum suspension for later use.

[0033] (3) Application and mixing Use drones for spraying (inoculum suspension mode) or mechanical spreading (inoculum agent-soil mixture mode) to ensure the inoculum agent is evenly sprayed on the farmland. Immediately after application, perform rotary tillage or plowing to a depth of 15-20 cm to ensure the inoculum agent is fully mixed with straw and soil, reducing the amount of exposed straw on the surface.

[0034] (4) Water management Irrigate within 24 hours after application or utilize natural rainfall to bring the soil moisture content of the 0-20 cm layer to 60%-70% of field capacity. In dryland areas, furrow irrigation or drip irrigation can be used, while in rice-growing areas, maintain a shallow water layer of 2-3 cm for 3-5 days to promote the activation of the inoculant and the water absorption and swelling of the straw.

[0035] Comparative Example 1 Blank control group (no bacterial treatment).

[0036] Comparative Example 2 Compared to Example 1, the compound microbial agent consists only of Neurospora crassa (… Neurospora crassa N7 and Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia The composition is JGDQ29-2, and the rest of the process is consistent with Example 1.

[0037] Comparative Example 3 Compared to Example 1, the compound microbial agent consists of Neurospora crassa (… Neurospora crassa N7, Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia JGDQ29-2 and Penicillium oxalate ( Penicillium oxalicum It consists of ATCC 10476, and the rest of the process is consistent with Example 1.

[0038] Comparative Example 4 Compared to Example 1, the compound microbial agent consists of Neurospora crassa (… Neurospora crassa N7, Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia JGDQ29-2, Trichoderma reesei ( Trichoderma reesei ATCC56765, Bacillus subtilis ( Bacillus subtilis The ATCC6633 is used, and the rest of the process is the same as in Example 1.

[0039] Test case 1. Low-temperature pot experiment on in-situ decomposition of straw Stenotrophomonas maltophilia JGDQ29-2 was inoculated into 10 mL of LB liquid medium and cultured overnight at 30°C with shaking. The seed culture was inoculated at a rate of 1% and transferred to 500 mL of LB liquid medium. The culture was then carried out on a shaker at 30°C and 200 rpm for 12 h.

[0040] Weissella esculenta zqw76 was inoculated into 10 mL of MRS liquid medium and incubated at 37°C overnight. The seed culture was then transferred to 500 mL of MRS liquid medium at a 1% inoculation rate and incubated for 12 h.

[0041] Inoculate *Neurospora crassa* N7 or *Aspergillus terreus* 10-80 spores into a 250 mL baffled shake flask containing 50 mL of straw-inorganic salt liquid medium and incubate at 25°C and 150 rpm for 48 h on a shaker. Take more than 15 mL of the bacterial culture and inoculate it into 500 mL of straw-inorganic salt liquid medium, then incubate at 25°C and 150 rpm for 48 h on a shaker.

[0042] Inorganic salt culture medium with straw as the sole carbon source: First, cut corn straw into straw segments about 2 cm long. Then, cut each straw segment into four pieces. Weigh 2 g of the cut straw pieces, add 10 mL of 5× M9 solution and 38 mL of distilled water into a 150 mL shake flask, and autoclave at 115℃ for 20 min. After cooling, add the following filtered and sterilized trace element solutions: 500 μL NaNO3 (2.5 g / 10 mL), 500 μL CaCl2 (0.11 g / 10 mL), 100 μL MgSO4·7H2O (2.465 g / 10 mL), 50 μL FeCl3·6H2O (0.162 g / 10 mL), 50 μL CuSO4·5H2O (2.496 g / 10 mL), 50 μL ZnSO4·7H2O (0.288 g / 10 mL), and 50 μL MnSO4·H2O (0.34 g / 10 mL). 5× M9 solution: 64 g Na2HPO4·7H2O, 15 g KH2PO4, 2.5 g NaCl, 5 g NH4Cl, dissolve in water and bring to a final volume of 1000 mL, then adjust the pH to 7.2 ± 0.2.

[0043] The compound microbial agent contains 1×10⁻⁸ g of each of Neurospora crassa N7 and Aspergillus terrestris. 7 1 spore / cell, corresponding to an inoculum size of 1×10⁶ for Stenotrophomonas maltophilia JGDQ29-2 and Weissella salina zqw76. 9 The bacterial sludge of the four strains was mixed evenly according to different treatment groups, and distilled water was added to make up to 50 mL to obtain the bacterial solution to be applied.

[0044] Garden soil was sieved through a 4-mesh sieve to remove stones and other debris. 10 g of straw was weighed, mixed thoroughly with 50 mL of the prepared bacterial solution, and then combined with 1.8 kg of garden soil. The mixture was then placed in a box measuring 11.8 cm x 12.6 cm x 15 cm and placed indoors at 4–8°C, with regular watering to maintain soil moisture at no less than 40%. The control group (CK) used 50 mL of sterile water to mix with the straw. After 60 days of incubation at 4–8°C, the soil in the box was sieved through a 4-mesh sieve to remove any undecomposed straw. The removed straw was rinsed with 80 mL of distilled water, dried in a 60°C oven, and the straw decomposition rate was measured. A 10 g sample of soil from the box was taken using a five-point sampling method, sieved through a 100-mesh sieve, and analyzed for organic matter content using a potassium dichromate oxidation-spectrophotometric method.

[0045] The method for determining the straw decomposition rate is as follows: After washing the straw using the above treatment method, dry it at 60℃ and weigh the remaining straw. The decomposition rate is calculated using the following formula: ; In the formula, W0 It is the original dry weight of straw. W1 It is the dry weight of the straw after decomposition.

[0046] The method for determining organic matter content is as follows: After air-drying the soil sample, pass it through a 0.25 mm sieve. Weigh a certain amount of soil sample into a test tube, add 10 mL of 0.4 mol / L potassium dichromate-sulfuric acid solution and shake well. Place a glass funnel at the mouth of the test tube, insert it into an iron wire furnace, and place it in oil at 170-180℃. Let the solution in the test tube boil for 5 minutes. After cooling, transfer the liquid and soil sample in the test tube to an Erlenmeyer flask. Also transfer the washing solution used to clean the test tube and funnel to the Erlenmeyer flask, bringing the final volume to 50-60 mL. Add 3 drops of o-phenanthroline indicator and titrate the remaining potassium dichromate with ferrous sulfate solution. Take approximately 0.2 g of ignited pumice powder or soil as a blank test. The formula for calculating soil organic matter is as follows: ; In the formula, I AM The mass fraction of soil organic matter (g / kg); c The concentration (mol / L) of the ferrous sulfate standard solution. V0 The volume (mL) of ferrous sulfate standard solution consumed during the blank test; V The volume of ferrous sulfate standard solution consumed during sample determination (mL); 0.003 is the millimolecular mass of 1 / 4 carbon atom (g); 1.10 is the oxidation correction factor; m The value is the mass (g) of the dried sample; 1.724 is the conversion factor of organic matter to organic carbon; 1000 is the coefficient for converting the result to content per kilogram.

[0047] Table 1 Evaluation of the effect of microbial agents on in-situ decomposition and quality improvement of straw under low temperature (4~8℃) conditions in soil

[0048] As shown in Table 1, Comparative Example 1, which did not use the microbial agent and served as the control group, had an in-situ straw decomposition rate of 42.2 ± 2.6%. Example 1, which used the compound microbial agent of this invention, achieved a decomposition rate of 63.8 ± 2.4%, representing a 51.2% increase compared to Comparative Example 1. After 60 days of in-situ straw decomposition in Comparative Example 1, the total organic matter (SOM) content was 1.78 ± 0.2 g / kg, while in Example 1 it was 3.21 ± 0.1 g / kg, indicating an 80.3% increase in soil organic matter content. Comparative Examples 2 and 3 did not show a significant effect on increasing soil organic matter. Soil pot experiments verified that the compound microbial agent prepared in this invention can effectively improve straw decomposition efficiency and soil organic matter content under low-temperature conditions (4~8℃), promoting the accumulation of organic matter in the soil.

[0049] 2. Field application effect (1) Application effect in paddy fields In order to accurately determine the in-situ decomposition performance of rice straw, this invention uses the PVC pipe method to measure the in-situ decomposition of rice straw.

[0050] PVC pipe method: Use perforated PVC pipes with a diameter of 12-16 cm, a length of 23-25 ​​cm, and a thickness of 3-5 mm. Each PVC pipe contains a measured mixture of rice straw, soil, and microbial agent. Weigh 34 g of rice straw and mix it thoroughly with 170 mL of microbial agent. Then, mix this mixture with a certain amount of soil sample, ensuring that each experimental group contains 3 × 10⁻⁶ bacteria. 9 CFU / tube, fungi 3×10 7 One spore / tube was used to position the prepared PVC pipe in the field. Each experimental group had 3 replicates and 4 sampling time points, for a total of 12 PVC pipes. Sampling was carried out approximately every 40 days from the application of the inoculant until the crop harvest, with three replicates taken from each experimental group each time.

[0051] Small-scale experiment: Experimental fields of approximately 10-50 mu (approximately 1.65-2.7 hectares) were selected. A microbial agent was sprayed before spring planting, and the application time was determined based on the optimal planting time. The application rate was 3.75 × 10⁻⁶ bacteria. 12 CFU / mu, fungi 3.75×10 11 1 spore / acre. The plot experiment was conducted in September and October, and the yield was measured according to the local crop growth conditions. The results are shown in Table 2.

[0052] Table 2 Effects of different microbial inoculants on rice yield

[0053] As shown in Table 2, the yield of the present invention was significantly improved compared with the comparative treatment group, with the highest improvement rate reaching 10.29%.

[0054] (2) Application effect in corn fields In order to accurately determine the in-situ decomposition performance of corn stalks, this invention uses the mesh bag method to measure the in-situ decomposition of corn stalks.

[0055] Nylon mesh bag method: Use 40×60 cm mesh bags, each containing a measured amount of corn stalks, soil, and inoculant mixture. Each experimental group contains 3×10⁶ bacteria. 9 CFU / bag, fungi 3×10 7 The inoculant was applied using a standard of 1 spore / bag ratio. The amount of crop straw used was 40 g of corn straw, mixed thoroughly with a certain amount of soil sample. Finally, the mesh bags were buried in the soil at a depth of 30-50 cm and intervals of approximately 60 cm, positioned in the cornfield. Each experimental group had three replicates and four sampling time points, totaling 12 nylon mesh bags. Sampling was conducted approximately every 40 days from the application of the inoculant until crop harvest, with three replicates taken from each experimental group each time.

[0056] Small-scale experiment: Experimental fields of approximately 10-50 mu (approximately 1.65-2.7 hectares) were selected. A microbial agent was sprayed before spring planting, and the application time was determined based on the optimal planting time. The application rate was 3.75 × 10⁻⁶ bacteria. 12 CFU / mu, fungi 3.75×10 11 1 spore per acre. The plot experiment was conducted in September and October, and the yield was measured according to the local crop growth conditions. The results are shown in Table 3.

[0057] Table 3. Effects of different microbial inoculants on maize yield

[0058] As shown in Table 3, the yield of the present invention was significantly improved compared with the comparative treatment group.

[0059] (3) Application effect in soybean fields This embodiment describes an experiment using microbial agents in a rice-soybean crop rotation dryland field. The previous year's crop was corn, and after harvest, all corn stalks were returned to the field. This year, soybeans were planted. To accurately determine the in-situ decomposition performance of the corn stalks, this invention employs a mesh bag method to measure the in-situ decomposition of the corn stalks. The specific experimental description is the same as above, and the results are shown in Table 4.

[0060] Table 4. Effects of different microbial inoculants on soybean yield

[0061] As shown in Table 4, the yield of the present invention was significantly improved compared with the comparative treatment group, with the highest improvement rate reaching 23.18%.

[0062] 3. Comparative analysis of field experiments between compound microbial agents and nitrogen and fertilizer reduction treatment groups The compound microbial agent was applied to paddy fields, corn fields, and rice-soybean rotation dryland fields for experiments, with the specific experimental descriptions as above. The difference was that experimental group 1 was a design group with 20% nitrogen and fertilizer reduction, while experimental group 2 was a treatment group that applied the compound microbial agent of this invention on top of the 20% nitrogen and fertilizer reduction. Other specific experimental procedures were the same as described above, and the results are shown in Table 5.

[0063] Table 5. Effects of different nitrogen and fertilizer reduction methods on crop yield.

[0064] As shown in Table 5, after nitrogen reduction treatment of fertilizer, the compound microbial agent prepared by this invention can be used as a substitute for nitrogen reduction. When it is added to nitrogen-reducing fertilizer, it will not only not reduce the fertilizer fertility, but also further enhance the fertilizer's yield-increasing effect on corn, soybeans and rice.

[0065] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A compound microbial agent for in-situ decomposition of straw, characterized in that, The effective viable count of this compound microbial agent is ≥5.0×10⁻⁶. 9 cfu / g, which includes: Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia JGDQ29-2, with accession number CGMCC No. 27979, was deposited at the China General Microbiological Culture Collection Center on July 24, 2023; Weissella esculenta ( Weissella cibaria zqw76, with accession number CGMCC No. 25147, was deposited at the China General Microbiological Culture Collection Center on June 21, 2022. Neurospora crassa ( Neurospora crassa N7, with accession number CGMCC No. 40738, was deposited at the China General Microbiological Culture Collection Center on July 24, 2023. Aspergillus terreus ( Aspergillus terreus )10-80, with accession number CGMCC No. 41616, was deposited at the China General Microbiological Culture Collection Center on November 6, 2024.

2. The straw in-situ decomposition compound microbial agent according to claim 1, characterized in that, In the compound microbial agent, Stenotrophomonas maltophilia JGDQ29-2 has an effective viable count of 10-50%; Weissella maltophilia zqw76 has an effective viable count of 10-65%; Neurospora crassa N7 has an effective viable count of 15-55%; and Aspergillus terreus 10-80 has an effective viable count of 10-65%.

3. The straw in-situ decomposition compound microbial agent according to claim 2, characterized in that, In the compound microbial agent, Stenotrophomonas maltophilia JGDQ29-2 has an effective viable count of 25-35%; Weissella maltophilia zqw76 has an effective viable count of 20-30%; Neurospora crassa N7 has an effective viable count of 25-35%; and Aspergillus terreus 10-80 has an effective viable count of 15-25%.

4. A method for preparing the straw in-situ decomposition compound microbial agent according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Stenotrophomonas maltophilia JGDQ29-2 was inoculated into LB liquid medium and cultured at 30-35℃ with shaking for 16-24 h; (2) Inoculate Weissella esculenta zqw76 into MRS liquid medium and incubate at 35-40℃ for 16-24h. (3) Inoculate Neurospora crassa N7 and Aspergillus terreus 10-80 into PDA liquid medium and culture at 25-30℃ with shaking for 68-74h; (4) Mix the various microbial agents according to the proportion of live bacteria in the formula to obtain the compound microbial agent.

5. The use of the straw in-situ decomposition compound microbial agent according to any one of claims 1 to 3 in the preparation of straw return-to-field formulations.

6. The use of the straw in-situ decomposition compound microbial agent according to any one of claims 1 to 3 in the preparation of formulations to improve soil fertility.

7. The use of the straw in-situ decomposition compound microbial agent according to any one of claims 1 to 3 in the preparation of formulations to improve crop yield.

8. The use according to claim 7, characterized in that, The crops mentioned are rice, corn, or soybeans.

9. The use according to claim 7, characterized in that, The formulation is a nitrogen-reducing fertilizer. The compound microbial agent replaces 20-25% of the nitrogen fertilizer in the fertilizer, thus forming a nitrogen-reducing fertilizer.

10. A method for field application of the straw in-situ decomposition compound microbial agent according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Straw treatment Crush the straw to a length of ≤15 cm, spread it evenly on the field surface, and then perform rotary tillage on the crushed straw so that it is 15~20 cm below the surface. (2) Preparation of microbial agents Mix the compound microbial agent with the soil at a mass ratio of 1:10~15 to form a microbial agent-soil mixture. Alternatively, the bacterial agent can be prepared into a bacterial suspension for later use; (3) Application Apply the bacterial suspension or bacterial agent-soil mixture to the field treated in step (1) by spraying or spreading, and then cultivate it to a depth of 15-20 cm to fully mix it with straw and soil. (4) Water management Irrigate or utilize natural rainfall within 24 hours after application to bring the soil moisture content of the 0-20 cm layer to 60%-70% of field capacity, thereby promoting the activation of the microbial agent and the water absorption and swelling of the straw.

Images