Active agricultural probiotic compound fertilizer
By using modified polyglutamic acid and nanocellulose in agricultural probiotic compound fertilizers, a stable sustained release mechanism is formed, which solves the problem of poor results in existing fertilizers in unsuitable environments and achieves the durability of fertilizers Release and soil improvement promote plant growth and stress resistance.
Patent Information
- Application Number
- CN202411489822.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-01-07
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing agricultural probiotic compound fertilizers are not effective in unsuitable soil environments and are sensitive to sunlight and chemicals, and are complex to use and store.
Active agricultural probiotic compound fertilizer using polyglutamic acid composite materials, probiotic bacteria agents, potassium humate, chitosan, jasmonic acid, apatite powder and cellulase, through modification of polyglutamic acid and The combination of nanocellulose forms a stable complex and sustained release mechanism, improving the lasting release and biocompatibility of fertilizers in the soil.
The sustained release effect of fertilizer is achieved, the water retention and breathability of the soil is improved, the absorption and utilization of nutrients by plants is enhanced, the soil environment is improved, the plant growth and stress resistance is promoted, and the plant has good biodegradability.
Smart Images
Figure BDA0005099714440000101
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fertilizers, and in particular relates to an active agricultural probiotic compound fertilizer. Background Art
[0002] Agricultural probiotic compound fertilizers provide specific fertilizer effects for crops and significantly improve soil fertility through the life activities of agricultural probiotics and other microorganisms and their metabolites. The core of agricultural probiotic compound fertilizers is to use specific probiotics to improve the biological activity and chemical properties of the soil. These probiotics can rapidly reproduce in the soil to form a stable biological community, and decompose organic matter through their life activities to release nutrients such as nitrogen, phosphorus, and potassium required by plants. In addition, probiotics can also produce a variety of substances beneficial to plant growth during the metabolic process, such as plant growth hormones and enzymes, which can significantly promote the development of plant roots, improve the plant's ability to absorb water and nutrients, effectively inhibit harmful microorganisms in the soil, and reduce the occurrence of diseases and insect pests, thereby further improving the yield and quality of crops. Agricultural probiotic compound fertilizers can be applied to the soil as a base fertilizer before sowing to provide sufficient nutrient reserves for the entire growth period of crops, or they can be supplemented as a topdressing during the growth of crops to meet the needs of crops at different growth stages. In addition, the probiotics in the fertilizer can significantly increase the organic matter content of the soil, improve the soil's aggregate structure and physical and chemical properties, increase the soil's ability to retain water and fertilizer, and provide a more favorable environment for the growth of plant roots.
[0003] In the prior art, environmental factors such as soil temperature, humidity, pH, and organic matter content have a significant impact on traditional probiotic compound fertilizers. Under unsuitable environmental conditions, probiotics cannot function effectively, thus affecting the overall effect of the fertilizer. In addition, since fertilizers are mainly composed of live bacteria, they are sensitive to direct sunlight and mixed with chemicals such as pesticides, which increases the complexity of their use and storage. Summary of the invention
[0004] The purpose of the present invention is to provide an active agricultural probiotic compound fertilizer in view of the deficiencies of the prior art.
[0005] The purpose of the present invention can be achieved by the following technical solutions:
[0006] An active agricultural probiotic compound fertilizer comprises the following raw materials by weight: 30-40 parts of a polyglutamic acid composite material, 10-20 parts of a probiotic agent, 8-12 parts of potassium humate, 3-5 parts of chitosan, 0.1-0.2 parts of jasmonic acid, 3-6 parts of humic acid, 1-5 parts of apatite powder and 1-2 parts of cellulase.
[0007] Preferably, the following raw materials are included by weight: 30-35 parts of polyglutamic acid composite material, 10-15 parts of probiotics, 8-10 parts of potassium humate, 4-5 parts of chitosan, 0.1 parts of jasmonic acid, 4-6 parts of humic acid, 2-4 parts of apatite powder and 1 part of cellulase.
[0008] Furthermore, the polyglutamic acid composite material is prepared by the following steps:
[0009] S1. The activated carbon is washed with 5% dilute hydrochloric acid, dried at 105-115°C for 2-4h, transferred to a high-temperature furnace, activated at 800-900°C for 2-3h, with a heating rate of 5°C / min, then immersed in a 5-10% silicate solution, ultrasonically treated for 30-40min, with an ultrasonic power of 40-50kHz, filtered, and dried in an oven at 80-90°C for 12-24h to obtain a supported silicate;
[0010] S2. Prepare a 5-7% sodium alginate solution at 60-70° C., add calcium chloride and supported silicate, stir rapidly at 700-800 rpm for 5-10 min, let stand for 1-2 h, filter, and wash with deionized water for 3-5 times to obtain cross-linked sodium alginate;
[0011] S3. Add cross-linked sodium alginate and modified polyglutamic acid into a twin-screw extruder, set the temperature to 220-240° C., the screw speed to 100-200 rpm, the mixing time to 10-20 min, and dry in an oven at 60-70° C. to constant weight to obtain a polyglutamic acid composite material.
[0012] The bacterial flora of the probiotic agent includes one or more of Bacillus subtilis, Bacillus licheniformis, Azospirillum, Bifidobacterium and Bacillus megaterium.
[0013] The usage ratio of activated carbon and silicate solution in step S1 is (10-12) g: (25-30) mL.
[0014] The silicate in step S1 includes one or more of sodium silicate, magnesium silicate, potassium silicate, calcium silicate and aluminum silicate.
[0015] In the step S2, the dosage ratio of the sodium alginate solution, calcium chloride and supported silicate is (150-200) mL: (7-9) g: (12-16) g.
[0016] The mass ratio of cross-linked sodium alginate to modified polyglutamic acid in step S3 is (8-12): (2-5).
[0017] Furthermore, the modified polyglutamic acid in step S3 comprises the following steps:
[0018] A1. Cut kraft wood pulp into small pieces and soak them in deionized water. Use a high-speed stirrer to stir the pieces at 1000-2000 rpm for 30-40 min. Use a high-pressure homogenizer to homogenize the pieces 5 times at a pressure of 20000-25000 psi, with an interval of 5-10 min each time. Use vacuum filtration and wash the pieces with deionized water for 3-5 times to obtain nanocellulose.
[0019] A2. Add polyglutamic acid to deionized water, heat to 40-50° C., add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stir at 200-300 rpm for 10-20 min, add to nanocellulose, adjust the pH value to 5.5-6.5, stir at room temperature at 400-600 rpm for 24-48 h, dialyze with a dialysis bag (MWCO 12000-14000) for 3-4 days, change the water 3-4 times a day, and obtain modified polyglutamic acid.
[0020] In the step A2, the mass ratio of polyglutamic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide and nanocellulose is (30-40): (0.3-0.5): (0.1-0.2): (15-20).
[0021] Beneficial effects of the present invention:
[0022] 1. In the technical solution of the present invention, the carboxyl group (-COOH) and other functional groups on the modified polyglutamic acid polymer chain can form a stable complex or chelate with the nutrient elements in the fertilizer. Due to the flexibility and steric hindrance effect of the polymer chain, the release in the soil becomes slow and lasting, thereby achieving a slow release of nutrients. Nanocellulose fills the micropores of the soil, and through its high specific surface area and nanoscale structural characteristics, it effectively improves the physical properties of the soil, increases the specific surface area of the soil, and enables the soil to absorb more water while maintaining the connectivity of the pores, thereby improving the water retention and air permeability of the soil.
[0023] 2. In the technical solution of the present invention, the carboxyl group of polyglutamic acid has negative charge and can combine with positively charged cations in the soil through ionic bonds, so that the cations are enriched near the plant roots, which is convenient for the plant to absorb through active transport or passive diffusion. At the same time, the combination of modified polyglutamic acid and heavy metal ions reduces the absorption of harmful substances by plants.
[0024] 3. In the technical solution of the present invention, the polyglutamic acid composite material enhances the stress resistance of plants by stimulating the expression of stress resistance genes in plants or regulating the level of plant hormones, binding to receptors on plant cell walls or cell membranes, triggering a series of signal transduction processes, and ultimately leading to the upregulation of the expression of stress resistance-related genes. The polyglutamic acid composite material is derived from natural polymers, and its molecular structure is similar to that of substances in organisms, so it has good biocompatibility. In addition, the molecular chain of the polyglutamic acid composite material contains biodegradable ester bonds or amide bonds, so that they can be gradually degraded into small molecules under the action of soil microorganisms, thereby achieving environmental protection.
[0025] 4. In the technical solution of the present invention, the polyglutamic acid composite material in the composite fertilizer not only enhances the slow-release performance of the fertilizer, but also effectively improves the soil's ability to retain water and nutrients. The ultrafine size of nanocellulose enables it to fill soil micropores, increase the specific surface area of the soil, thereby improving the water retention and air permeability of the soil, and providing a good living environment for probiotics. Secondly, probiotics can convert ineffective nutrients in the soil into effective nutrients that can be directly absorbed by plants through biological nitrogen fixation, phosphorus solubilization, potassium solubilization, etc. In addition, probiotics can also secrete a variety of plant growth hormones and antibacterial substances, promote plant root development, enhance plant resistance, and inhibit the growth of harmful microorganisms. Potassium humate can improve soil structure and increase soil ion exchange capacity; chitosan has good biocompatibility and antibacterial properties; jasmonic acid and humic acid can stimulate plant growth and stress resistance. Apatite powder and cellulase not only provide plants with the essential nutrient of phosphorus, but also promote the decomposition of cellulose in the soil through the action of cellulase, releasing more available nutrients. DETAILED DESCRIPTION
[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0027] Example 1
[0028] The modified polyglutamic acid comprises the following steps:
[0029] A1. Cut kraft wood pulp into small pieces and soak them in deionized water. Stir them with a high-speed stirrer at 1000 rpm for 30 min. Homogenize them with a high-pressure homogenizer at a pressure of 20000 psi for 5 times, with an interval of 5 min each time. Vacuum filter them and wash them with deionized water for 3 times to obtain nanocellulose.
[0030] A2. Add 300 g of polyglutamic acid to 1000 mL of deionized water, heat to 40 ° C, add 3 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1 g of N-hydroxysuccinimide, stir at 200 rpm for 10 min, add to 150 g of nanocellulose, adjust the pH value to 5.5, stir at room temperature at 400 rpm for 24 h, dialyze with a dialysis bag for 3 days, change the water 3 times a day, and obtain modified polyglutamic acid.
[0031] Example 2
[0032] The modified polyglutamic acid comprises the following steps:
[0033] A1. Cut kraft wood pulp into small pieces and soak them in deionized water. Stir them with a high-speed stirrer at 1500 rpm for 35 min. Homogenize them with a high-pressure homogenizer at a pressure of 22500 psi for 5 times, with an interval of 8 min each time. Vacuum filter them and wash them with deionized water for 4 times to obtain nanocellulose.
[0034] A2. Add 3050 g of polyglutamic acid to 1000 mL of deionized water, heat to 45 ° C, add 4 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.5 g of N-hydroxysuccinimide, stir at 250 rpm for 15 min, add to 175 g of nanocellulose, adjust the pH value to 6.0, stir at room temperature at 500 rpm for 36 h, dialyze with a dialysis bag for 3 days, change the water 3 times a day, and obtain modified polyglutamic acid.
[0035] Example 3
[0036] The modified polyglutamic acid comprises the following steps:
[0037] A1. Cut kraft wood pulp into small pieces and soak them in deionized water. Use a high-speed stirrer to stir for 40 min at 2000 rpm. Use a high-pressure homogenizer to homogenize 5 times at a pressure of 25000 psi, each time with an interval of 10 min. Use vacuum filtration, and then wash with deionized water 5 times to obtain nanocellulose.
[0038] A2. Add 400 g of polyglutamic acid to 1000 mL of deionized water, heat to 50 ° C, add 5 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 2 g of N-hydroxysuccinimide, stir at 300 rpm for 20 min, add to 200 g of nanocellulose, adjust the pH value to 6.5, stir at room temperature at 600 rpm for 48 h, dialyze with a dialysis bag for 4 days, change the water 4 times a day, and obtain modified polyglutamic acid.
[0039] Example 4
[0040] The polyglutamic acid composite material comprises the following steps to prepare:
[0041] S1. Wash 100 g of activated carbon with 5% dilute hydrochloric acid, dry at 105°C for 2 h, transfer to a high-temperature furnace, activate at 800°C for 2 h, with a heating rate of 5°C / min, then soak in 250 mL of 5% sodium silicate solution, ultrasonically treat for 30 min at an ultrasonic power of 40 kHz, filter, and dry in an oven at 80°C for 12 h to obtain a supported silicate;
[0042] S2. Prepare 1500 mL of 5% sodium alginate solution at 60-70° C., add 70 g of calcium chloride and 120 g of supported silicate, stir rapidly at 700 rpm for 5 min, let stand for 1 h, filter, and wash with deionized water 3 times to obtain cross-linked sodium alginate;
[0043] S3. Add 80 g of cross-linked sodium alginate and 20 g of the modified polyglutamic acid obtained in Example 1 into a twin-screw extruder, set the temperature to 220° C., the screw speed to 100 rpm, the mixing time to 10 min, and dry in an oven at 60° C. to constant weight to obtain a polyglutamic acid composite material.
[0044] Example 5
[0045] The polyglutamic acid composite material comprises the following steps to prepare:
[0046] S1. Wash 110 g of activated carbon with 5% dilute hydrochloric acid, dry at 110°C for 3 h, transfer to a high-temperature furnace, activate at 850°C for 2.5 h, with a heating rate of 5°C / min, then soak in 275 mL of 7.5% sodium silicate solution, ultrasonically treat for 35 min at an ultrasonic power of 45 kHz, filter, and dry in an oven at 85°C for 18 h to obtain a supported silicate;
[0047] S2. Prepare 1750 mL of 6% sodium alginate solution at 65° C., add 80 g of calcium chloride and 140 g of supported silicate, stir rapidly at 750 rpm for 7.5 min, let stand for 1.5 h, filter, and wash with deionized water 4 times to obtain cross-linked sodium alginate;
[0048] S3. Add 100 g of cross-linked sodium alginate and 35 g of modified polyglutamic acid obtained in Example 2 into a twin-screw extruder, set the temperature to 230° C., the screw speed to 150 rpm, the mixing time to 15 min, and dry in an oven at 65° C. to constant weight to obtain a polyglutamic acid composite material.
[0049] Example 6
[0050] The polyglutamic acid composite material comprises the following steps to prepare:
[0051] S1. Wash 120 g of activated carbon with 5% dilute hydrochloric acid, dry at 115°C for 4 h, transfer to a high-temperature furnace, activate at 900°C for 3 h, with a heating rate of 5°C / min, then soak in 300 mL of 10% sodium silicate solution, ultrasonically treat for 40 min at an ultrasonic power of 50 kHz, filter, and dry in an oven at 90°C for 24 h to obtain a supported silicate;
[0052] S2. Prepare 2000 mL of 7% sodium alginate solution at 70° C., add 90 g of calcium chloride and 160 g of supported silicate, stir rapidly at 800 rpm for 10 min, let stand for 2 h, filter, and wash with deionized water 5 times to obtain cross-linked sodium alginate;
[0053] S3. Add 120 g of cross-linked sodium alginate and 50 g of modified polyglutamic acid obtained in Example 3 into a twin-screw extruder, set the temperature to 240° C., the screw speed to 200 rpm, the mixing time to 20 min, and dry in an oven at 70° C. to constant weight to obtain a polyglutamic acid composite material.
[0054] Example 6
[0055] An active agricultural probiotic compound fertilizer comprises the following raw materials by weight: 30-40 parts of a polyglutamic acid composite material, 10-20 parts of a probiotic agent, 8-12 parts of potassium humate, 3-5 parts of chitosan, 0.1-0.2 parts of jasmonic acid, 3-6 parts of humic acid, 1-5 parts of apatite powder and 1-2 parts of cellulase.
[0056] Example 7
[0057] An active agricultural probiotic compound fertilizer comprises the following raw materials by weight: 31 parts of the polyglutamic acid composite material prepared in Example 4, 12 parts of probiotic agents, 9 parts of potassium humate, 3 parts of chitosan, 0.1 parts of jasmonic acid, 3 parts of humic acid, 2 parts of apatite powder and 1 part of cellulase.
[0058] Example 8
[0059] An active agricultural probiotic compound fertilizer comprises the following raw materials by weight: 35 parts of the polyglutamic acid composite material prepared in Example 5, 16 parts of probiotic agents, 10 parts of potassium humate, 4 parts of chitosan, 0.1 parts of jasmonic acid, 5 parts of humic acid, 2 parts of apatite powder and 1 part of cellulase.
[0060] Example 9
[0061] An active agricultural probiotic compound fertilizer comprises the following raw materials by weight: 40 parts of the polyglutamic acid composite material prepared in Example 6, 20 parts of probiotic agents, 12 parts of potassium humate, 5 parts of chitosan, 0.2 parts of jasmonic acid, 6 parts of humic acid, 5 parts of apatite powder and 2 parts of cellulase.
[0062] Comparative Example 1
[0063] The difference between this comparative example and Example 7 is that activated carbon is used instead of the polyglutamic acid composite material.
[0064] Comparative Example 2
[0065] The difference between this comparative example and Example 8 is that polyglutamic acid is used instead of the polyglutamic acid composite material.
[0066] The compound fertilizers prepared in Examples 7-9 and Comparative Examples 1-2 were respectively mixed with soil at a mass ratio of 1:3 and placed in flower pots. A control group was set up. No compound fertilizer was added to the control group. 20 cotton seeds were planted in each pot to ensure that all potted plants received the same light, temperature and water conditions. Samples were taken when the cotton fruits were formed, and physiological indicators such as nutrient content and chlorophyll content in the plants were measured. The results are shown in Table 1:
[0067] Table 1. Results of cotton physiological indicators of Examples 7-9, Comparative Examples 1-2 and the control group
[0068]
[0069] As shown in Table 1, the cotton of Examples 7-9 is significantly superior to the control group, Comparative Example 1 and Comparative Example 2 in terms of physiological indicators such as plant height, chlorophyll content, net photosynthetic rate, leaf nitrogen content and yield, indicating that the active agricultural probiotic compound fertilizer used in Examples 7-9 has a significant promoting effect on the growth of cotton. The compound fertilizer of Examples 7-9 contains a polyglutamic acid composite material, which may enhance the slow-release effect of the fertilizer through its unique structure and properties, and improve the absorption and utilization efficiency of nutrients by plants. The combination of nanocellulose and polyglutamic acid in the polyglutamic acid composite material may enhance the adhesion and stability of the fertilizer, making the fertilizer release in the soil slower and more lasting, providing a continuous and stable nutrient supply for cotton. In addition, the probiotic agent, potassium humate, chitosan and other ingredients in the compound fertilizer may also play a positive role in promoting the growth of cotton. Probiotic agents can improve the soil microbial environment and improve soil fertility; potassium humate and chitosan may provide the trace elements and organic matter required for cotton growth, promoting the growth and development of cotton.
[0070] In contrast, in Comparative Example 1, activated carbon is used instead of the polyglutamic acid composite material. Although the activated carbon has a certain adsorption capacity and slow-release effect, its ability to bind fertilizers may be weak, resulting in the fertilizer being released too quickly in the soil, and failing to meet the sustained and stable nutritional needs of cotton. In Comparative Example 2, polyglutamic acid is used instead of the polyglutamic acid composite material. Although polyglutamic acid itself has a certain slow-release effect, it lacks the reinforcing effect of nanocellulose, and its slow-release effect and stability may not be as good as those of the polyglutamic acid composite material.
[0071] In summary, the active agricultural probiotic compound fertilizers of Examples 7-9 significantly promote cotton growth, which not only improves the physiological indicators of cotton, but also creates conditions for high yield and high quality of cotton by improving the soil environment and improving nutrient utilization efficiency.
[0072] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0073] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.
Claims
1. An active agricultural probiotic compound fertilizer, characterized in that: The raw materials include the following by weight: 30-40 parts of polyglutamic acid composite material, 10-20 parts of probiotics, 8-12 parts of potassium humate, 3-5 parts of chitosan, 0.1-0.2 parts of jasmonic acid, 3-6 parts of humic acid, 1-5 parts of apatite powder and 1-2 parts of cellulase.
2. The active agricultural probiotic compound fertilizer according to claim 1, characterized in that: The polyglutamic acid composite material comprises the following steps to prepare: S1. The activated carbon is washed with 5% dilute hydrochloric acid, dried at 105-115°C for 2-4h, transferred to a high-temperature furnace, activated at 800-900°C for 2-3h, with a heating rate of 5°C / min, then immersed in a 5-10% silicate solution, ultrasonically treated for 30-40min, with an ultrasonic power of 40-50kHz, filtered, and dried in an oven at 80-90°C for 12-24h to obtain a supported silicate; S2. Prepare a 5-7% sodium alginate solution at 60-70° C., add calcium chloride and supported silicate, stir rapidly at 700-800 rpm for 5-10 min, let stand for 1-2 h, filter, and wash with deionized water for 3-5 times to obtain cross-linked sodium alginate; S3. Add cross-linked sodium alginate and modified polyglutamic acid into a twin-screw extruder, set the temperature to 220-240° C., the screw speed to 100-200 rpm, the mixing time to 10-20 min, and dry in an oven at 60-70° C. to constant weight to obtain a polyglutamic acid composite material.
3. The active agricultural probiotic compound fertilizer according to claim 1, characterized in that: The bacterial flora of the probiotic preparation includes one or more of Bacillus subtilis, Bacillus licheniformis, Azospirillum, Bifidobacterium and Bacillus megaterium.
4. The active agricultural probiotic compound fertilizer according to claim 2, characterized in that: The usage ratio of activated carbon and silicate solution in step S1 is (10-12) g: (25-30) mL.
5. The active agricultural probiotic compound fertilizer according to claim 2, characterized in that: The silicate in step S1 includes one or more of sodium silicate, magnesium silicate, potassium silicate, calcium silicate and aluminum silicate.
6. The active agricultural probiotic compound fertilizer according to claim 2, characterized in that: In step S2, the dosage ratio of sodium alginate solution, calcium chloride and supported silicate is (150-200) mL: (7-9) g: (12-16) g.
7. The active agricultural probiotic compound fertilizer according to claim 2, characterized in that: The mass ratio of cross-linked sodium alginate to modified polyglutamic acid in step S3 is (8-12): (2-5).
8. The active agricultural probiotic compound fertilizer according to claim 2, characterized in that: The modified polyglutamic acid in step S3 comprises the following steps: A1. Cut kraft wood pulp into small pieces and soak them in deionized water. Use a high-speed stirrer to stir the pieces at 1000-2000 rpm for 30-40 min. Use a high-pressure homogenizer to homogenize the pieces 5 times at a pressure of 20000-25000 psi, with an interval of 5-10 min each time. Use vacuum filtration and wash the pieces with deionized water for 3-5 times to obtain nanocellulose. A2. Add polyglutamic acid to deionized water, heat to 40-50° C., add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stir at 200-300 rpm for 10-20 min, add to nanocellulose, adjust the pH value to 5.5-6.5, stir at 400-600 rpm at room temperature for 24-48 h, dialyze with a dialysis bag for 3-4 days, change the water 3-4 times a day, and obtain modified polyglutamic acid.
9. The active agricultural probiotic compound fertilizer according to claim 8, characterized in that: In step A2, the mass ratio of polyglutamic acid, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide and nanocellulose is (30-40):(0.3-0.5):(0.1-0.2):(15-20).