Microbial fertilizer with drought-resistant, water-retaining and slow-release effects as well as preparation method and application of microbial fertilizer

Abstract

The invention belongs to the technical field of agricultural fertilizers, and particularly relates to a microbial fertilizer with drought-resistant, water-retaining and slow-release effects as well as a preparation method and application of the microbial fertilizer. The microbial fertilizer provided by the invention sequentially comprises a nano enzyme with peroxidase activity, a mesoporous material, a compound fertilizer, a carrier, microorganisms and a double-network hydrogel shell from inside to outside. By utilizing the mesoporous material, on one hand, the dispersed state of the nano core can be maintained, and on the other hand, the compound fertilizer in contact with the surface of the mesoporous nano material not only plays a role of a fertilizer, but also plays a role of packaging the mesoporous nano material. According to the invention, the gap between each two layers of components is fully utilized, so that each component plays a role. Besides, the nano-enzyme is added into the formula, so that the effects of improving the utilization efficiency of the fertilizer and promoting the metabolic regulation of plants in the growth process of crops can be achieved, and the effects of increasing the yield on the scene and stabilizing the yield under the adverse condition are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural fertilizers, and in particular relates to a microbial fertilizer with drought resistance, water retention and slow-release effects, and a preparation method and application thereof. Background Art

[0002] Fertilizer and water resource utilization are important material bases for agricultural production and development, and it is crucial to improve the utilization rate of fertilizer and water resources. At present, one of the ways to improve fertilizer utilization is to use slow-release fertilizers. Slow-release fertilizers refer to fertilizers that can slowly release nutrients and whose release pattern is consistent with the nutrient requirements of plants. In particular, coated fertilizers are one of the current mainstream types of slow-release fertilizers. They are formed by coating the surface of fertilizer particles. The nutrient release rate can be adjusted to match the nutrient absorption needs of crops, thereby achieving precise control of the nutrient release rate, thereby better meeting the nutrient needs of crops at different growth stages.

[0003] However, the existing research and technical applications are still relatively few on the application methods and improvement effects of different improvers such as natural humic acid and polymer water retaining agents. In addition, the existing water-retaining and drought-resistant effects of water-retaining and slow-release fertilizers are not good, and the absorption and utilization rate of fertilizers by crops is low. At present, there are still many problems to be solved in biomass-based water-retaining materials, such as the high cost of coating materials, the materials are too hydrophilic, the compatibility is poor, the nutrient release rate is fast, and it is not easy to degrade. Therefore, the development of a water-retaining and slow-release fertilizer is of great significance for water conservation and fertilizer saving, reducing pollution, improving the soil ecological environment, increasing the yield of agricultural and forestry economic crops, and achieving sustainable development of environmental economy. Summary of the invention

[0004] The purpose of the present invention is to provide a microbial fertilizer with drought resistance, water retention and slow release effects, and a preparation method and application thereof, so as to solve the technical problems of low space utilization rate of existing fertilizer particles, high production cost of water retention agents, and difficult degradation of residues.

[0005] The present invention provides a microbial fertilizer with drought resistance, water retention and slow release effects, wherein the microbial fertilizer comprises, from the inside to the outside, a nanoenzyme with peroxidase activity, a mesoporous material, a compound fertilizer, a carrier, a microorganism and a double-network hydrogel shell; The compound fertilizer comprises a large amount of NPK elements, trace elements and synergistic components; The synergistic components include one or more of seaweed extract, humic acid, biochar, zinc humic acid, and selenoamino acid; The carrier comprises a sodium carboxymethyl cellulose-sodium alginate composite carrier; The effective viable count of the microorganisms is ≥ 20-50 million / gram, and includes Bacillus subtilis, Bacillus laterosporus, Bacillus licheniformis, Bacillus thuringiensis, Bacillus amyloliquefaciens, Trichoderma harzianum, Aspergillus oryzae and Gliocladium roseum.

[0006] Preferably, the microbial fertilizer comprises the following components in parts by mass: 1 to 5 parts of nanoenzymes with peroxidase activity, 1 to 5 parts of mesoporous materials, 60 to 80 parts of compound fertilizers, 1 to 5 parts of carriers, 2 to 10 parts of microorganisms and 2 to 10 parts of double-network hydrogel shells.

[0007] Preferably, each portion of the compound fertilizer comprises the following components in parts by mass: 50-60 parts of macroelement NPK, 5-10 parts of trace elements, and 5-10 parts of synergistic components; Each portion of the microorganism comprises the following components in parts by mass: 1-2 parts of Bacillus subtilis, 1-2 parts of Bacillus laterosporus, 1-2 parts of Bacillus licheniformis, 1-2 parts of Bacillus thuringiensis, 1-2 parts of Bacillus amyloliquefaciens, 1-2 parts of Trichoderma harzianum, 1-2 parts of Aspergillus oryzae and 1-2 parts of Gliocladium roseum; The mass ratio of sodium carboxymethyl cellulose to sodium alginate in the carrier is (1-5): (1-5).

[0008] Preferably, the nanozyme having peroxidase activity comprises ferrosoferric oxide; The mesoporous material includes one or more of mesoporous silica, LDHs and mesoporous silica; The double network hydrogel shell comprises polyvinyl alcohol-glycerol / gelatin double network organic hydrogel.

[0009] Preferably, the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel comprises water, glycerol, polyvinyl alcohol and gelatin; The mass ratio of water to glycerol in the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel is (4-9): (1-6); The mass ratio of polyvinyl alcohol to gelatin in the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel is (5-9): (1-5); The total mass of the polyvinyl alcohol and gelatin accounts for 15-35% of the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel.

[0010] Preferably, the microbial fertilizer comprises, by mass, 1 to 5 parts of nanoenzymes with peroxidase activity, 1 to 5 parts of mesoporous materials, 60 to 80 parts of compound fertilizers, 1 to 5 parts of carriers, 2 to 10 parts of microorganisms and 2 to 10 parts of double-network hydrogel shells.

[0011] Preferably, the microbial fertilizer is in the form of granules.

[0012] The present invention also provides a method for preparing the microbial fertilizer described in the above technical solution, comprising the following steps: Nanozymes with peroxidase activity were loaded on mesoporous materials to obtain core-shell structures; The core-shell structure is encapsulated by using a compound fertilizer, granulated, and dried to obtain fertilizer core particles; The core particles of the fertilizer are coated with a carrier to obtain an inner-coated water-retaining slow-release fertilizer; The inner film water-retaining slow-release fertilizer is coated with microorganisms to obtain a microorganism layer coated fertilizer; The microbial layer-coated fertilizer is wrapped by a double-network hydrogel shell to obtain a microbial fertilizer.

[0013] Preferably, the loading method comprises a coprecipitation method and / or a Stöber method; The encapsulation method comprises: mixing and granulating the macroelement NPK in the compound fertilizer and the core-shell structure, and then mixing and granulating with other components in the compound fertilizer; The coating method comprises: spraying the carrier on the surface of the fertilizer core particles and then drying; The coating method comprises: spraying microorganisms on the surface of the inner-encapsulated water-retaining slow-release fertilizer; The encapsulation method comprises: heating the double network hydrogel shell at 60-80° C. to obtain a molten hydrogel; and granulating the fertilizer by soaking the microorganism layer in the molten hydrogel.

[0014] The present invention also provides the use of the microbial fertilizer described in the above technical solution or the microbial fertilizer obtained by the preparation method in plant cultivation.

[0015] Preferably, the plant cultivation includes stabilizing plant yields in adverse conditions and / or increasing plant yields in favorable conditions.

[0016] Beneficial effects: The present invention provides a microbial fertilizer with drought resistance, water retention and slow release effect, wherein the microbial fertilizer includes nanoenzymes with peroxidase activity, mesoporous materials, composite fertilizers, carriers, microorganisms and double network hydrogel shells from the inside to the outside; the composite fertilizer includes a large amount of NPK, trace elements and synergistic components; the synergistic components include seaweed extract, humic acid, biochar, zinc humic acid, selenoamino acid or more; the carrier includes sodium carboxymethyl cellulose-sodium alginate composite carrier; the effective viable count of the microorganism is ≥ 0.2-0.5 billion / gram, including Bacillus subtilis, Bacillus laterosporus, Bacillus licheniformis, Bacillus thuringiensis, Bacillus amyloliquefaciens, Trichoderma harzianum, Aspergillus oryzae and Glechoma rubrum. The present invention utilizes mesoporous materials, which can maintain the dispersed state of the nano kernel on the one hand, and on the other hand, the composite fertilizer in contact with the surface of the mesoporous nano material plays the role of fertilizer and the role of encapsulating the mesoporous nano material. The present invention makes full use of the gap between each two layers of the coating, and the introduced components are all functional components, so that each involved component can play a role and make the best use of it. The carrier and the double network hydrogel shell have a water-retaining and slow-release effect, and the microorganisms play a role in improving the stress resistance of plants. In addition, the present invention adds nanozymes to the formula, which can play a role in improving the efficiency of fertilizer utilization and promoting plant metabolic regulation during crop growth, and has the effect of increasing production in favorable circumstances and stabilizing production in adverse circumstances. The present invention uses mesoporous materials to load nanozymes as a core-shell structure. Compared with the micron-sized kernel, it has the advantages of improving the spatial utilization rate of fertilizer particles, promoting plant absorption, improving the soil environment, increasing crop yield and quality, and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0018] Figure 1 This is a scanning electron microscope (SEM) image of nano-iron tetroxide; Figure 2 is a scanning electron microscope (SEM) image of the porous silica nanocarrier; Figure 3 is the transmission electron microscopy (TEM) image of the porous silica nanocarrier; Figure 4 This is a schematic diagram of a sodium carboxymethyl cellulose-sodium alginate composite carrier; Figure 5 This is a partial picture of the surface of the microbial fertilizer particles obtained in Example 4; Figure 6 The finished product of the microbial fertilizer obtained in Example 4 is shown; Figure 7 This is a physical picture (side view) of the rapeseed growth in each treatment group of the rapeseed pot experiment in Application Example 1; Figure 8 This is a physical picture (top view) of the rapeseed growth in each treatment group of the rapeseed pot experiment in Application Example 1; Fig. 9 This is a real picture (top view) of the rapeseed growth in each treatment group of the rapeseed pot experiment in Application Example 2. DETAILED DESCRIPTION

[0019] The present invention provides a microbial fertilizer with drought resistance, water retention and slow release effects, wherein the microbial fertilizer comprises, from the inside to the outside, a nanoenzyme with peroxidase activity, a mesoporous material, a compound fertilizer, a carrier, a microorganism and a double-network hydrogel shell; The compound fertilizer comprises a large amount of NPK elements, trace elements and synergistic components.

[0020] The synergistic components include one or more of seaweed extract, humic acid, biochar, zinc humic acid, and selenoamino acid; The carrier comprises a sodium carboxymethyl cellulose-sodium alginate composite carrier; The effective viable count of the microorganisms is ≥ 20-50 million / gram, and includes Bacillus subtilis, Bacillus laterosporus, Bacillus licheniformis, Bacillus thuringiensis, Bacillus amyloliquefaciens, Trichoderma harzianum, Aspergillus oryzae and Gliocladium roseum.

[0021] As one embodiment, the microbial fertilizer of the present invention comprises the following components in parts by mass: 1 to 5 parts of nanozymes with peroxidase activity, 1 to 5 parts of mesoporous materials, 60 to 80 parts of compound fertilizers, 1 to 5 parts of carriers, 2 to 10 parts of microorganisms, and 2 to 10 parts of double-network hydrogel shells; as another embodiment, the microbial fertilizer of the present invention comprises the following components in parts by mass: the microbial fertilizer comprises 2.5 parts of nanozymes with peroxidase activity, 2.5 parts of mesoporous materials, 75 parts of compound fertilizers, 5 parts of carriers, 10 parts of microorganisms, and 5 parts of double-network hydrogel shells.

[0022] As an embodiment, the nanozyme with peroxidase activity of the present invention includes ferroferric oxide. The present invention uses the nanozyme with peroxidase activity as the core structure of the microbial fertilizer, which has the effect of promoting plant metabolic regulation. The present invention has no strict requirements on the preparation method of the nanozyme with peroxidase activity, and conventional methods in the art can be used, such as ball milling, chemical coprecipitation, hydrothermal synthesis, microemulsion, microwave hydrothermal, high temperature decomposition, sol-gel, oxidation, etc.

[0023] As an embodiment, the mesoporous material of the present invention includes one or more of mesoporous silicon, LDHs and mesoporous silica; as another embodiment, the mesoporous material of the present invention is silica. The present invention utilizes the mesoporous material to maintain the dispersed state of the nano-core, and can also provide silicon for plant growth. The present invention has no strict requirements on the preparation method of the mesoporous material, and conventional methods in the art can be used, such as continuous reduction method, co-reduction method, sol-gel method, chemical plating method, co-precipitation method, hydrothermal method, surface modification method, hot injection method, etc.

[0024] As an embodiment, each portion of the compound fertilizer of the present invention comprises the following components in mass parts: 50-60 parts of a large element NPK, 5-10 parts of trace elements and 5-10 parts of synergistic components. As an embodiment, the synergistic component of the present invention is humic acid. As another embodiment, each portion of the compound fertilizer of the present invention comprises the following components in mass parts: the compound fertilizer comprises 60 parts of a large element NPK, 10 parts of trace elements and 5 parts of humic acid. As an embodiment, the large element NPK of the present invention comprises urea, monoammonium phosphate and potassium sulfate. As an embodiment, the mass ratio of urea, monoammonium phosphate and potassium sulfate in the large element NPK of the present invention is 1:1:1. The present invention utilizes the compound fertilizer to provide the required nutrition for plant growth and enhance nutrient absorption. In the present invention, the mass fractions of the urea, monoammonium phosphate and potassium sulfate are respectively based on the mass of the N element in urea, the P phosphorus element in monoammonium phosphate and the K element in potassium sulfate.

[0025] As an embodiment, the mass ratio of sodium carboxymethyl cellulose and sodium alginate in the carrier is (1-5): (1-5); as another embodiment, the mass ratio of sodium carboxymethyl cellulose and sodium alginate in the carrier is 2.5: 2.5. The present invention utilizes the sodium carboxymethyl cellulose-sodium alginate composite carrier to have the effect of water retention and sustained release.

[0026] As one embodiment, each portion of the microorganism described in the present invention comprises the following components in parts by mass: 1 to 2 parts of Bacillus subtilis, 1 to 2 parts of Bacillus laterosporus, 1 to 2 parts of Bacillus licheniformis, 1 to 2 parts of Bacillus thuringiensis, 1 to 2 parts of Bacillus amyloliquefaciens, 1 to 2 parts of Trichoderma harzianum, 1 to 2 parts of Aspergillus oryzae and 1 to 2 parts of Gliocladium roseum; as another embodiment, each portion of the microorganism described in the present invention comprises the following components in parts by mass: the microorganism described in the present invention comprises 1 part of Bacillus subtilis, 1 part of Bacillus laterosporus, 1 part of Bacillus licheniformis, 1 part of Bacillus thuringiensis, 1 part of Bacillus amyloliquefaciens, 1 part of Trichoderma harzianum, 1 part of Aspergillus oryzae and 1 part of Gliocladium roseum. The present invention utilizes microorganisms, wherein Bacillus subtilis prevents fungi, Bacillus laterosporus secretes beneficial substances to improve plant stress resistance, Bacillus licheniformis prevents and resists diseases, Bacillus thuringiensis avoids pests, Bacillus amyloliquefaciens improves crop stress resistance, Trichoderma harzianum prevents and controls fungal pests, Aspergillus oryzae produces metabolites beneficial to crops to prevent and control soil fungal diseases, and Glechoma rosea improves defense enzyme activity. The present invention compounds Bacillus subtilis, Bacillus laterosporus, Bacillus licheniformis, Bacillus thuringiensis, Bacillus amyloliquefaciens, Trichoderma harzianum, Aspergillus oryzae and Glechoma rosea, which can generally promote plant growth and improve plant stress resistance.

[0027] As an embodiment, the double network hydrogel shell of the present invention comprises a polyvinyl alcohol-glycerol / gelatin double network organic hydrogel. As an embodiment, the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel of the present invention comprises water, glycerol, polyvinyl alcohol and gelatin. As an embodiment, the mass ratio of water to glycerol in the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel of the present invention is (4-9): (1-6); as another embodiment, the mass ratio of water to glycerol in the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel of the present invention is 5.5:4.5. As an embodiment, the mass ratio of polyvinyl alcohol to gelatin in the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel of the present invention is (5-9): (1-5); as another embodiment, the mass ratio of polyvinyl alcohol to gelatin in the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel of the present invention is 6.5:3.5. As an embodiment, the total mass of the polyvinyl alcohol and gelatin in the present invention accounts for 15-35% of the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel; as another embodiment, the total mass of the polyvinyl alcohol and gelatin in the present invention accounts for 20% of the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel. The present invention utilizes the double network hydrogel shell to have the effect of water retention and sustained release.

[0028] As an embodiment, the dosage form of the microbial fertilizer of the present invention is a granule. The present invention defines that the structure of the microbial fertilizer from the inside to the outside includes nanoenzymes with peroxidase activity, mesoporous materials, compound fertilizers, carriers, microorganisms and double-network hydrogel shells in sequence, and the obtained microbial fertilizer can play the effects of drought resistance, water retention, slow release, stable production in adverse conditions and increased production in favorable conditions.

[0029] The present invention also provides a method for preparing the microbial fertilizer described in the above technical solution, comprising the following steps: Nanozymes with peroxidase activity were loaded on mesoporous materials to obtain core-shell structures; The core-shell structure is encapsulated by using a compound fertilizer, granulated, and dried to obtain fertilizer core particles; The core particles of the fertilizer are coated with a carrier to obtain an inner-coated water-retaining slow-release fertilizer; The inner film water-retaining slow-release fertilizer is coated with microorganisms to obtain a microorganism layer coated fertilizer; The microbial layer-coated fertilizer is wrapped by a double-network hydrogel shell to obtain a microbial fertilizer.

[0030] The present invention uses a mesoporous material to load a nanozyme with peroxidase activity to obtain a core-shell structure. As an embodiment, the loading method of the present invention includes a coprecipitation method and / or a Stöber method.

[0031] After obtaining the core-shell structure, the present invention uses a composite fertilizer to encapsulate the core-shell structure, granulate, and dry to obtain the fertilizer core particles. As an embodiment, the present invention grinds the composite fertilizer through a 40-100 mesh sieve, then uses the undersize to encapsulate the core-shell structure, granulate, and dry to obtain the fertilizer core particles. As an embodiment, the encapsulation method of the present invention includes: mixing and granulating the large amount of NPK in the composite fertilizer and the core-shell structure, and then mixing and granulating with other components in the composite fertilizer. As an embodiment, the particle size of the granulation is 1-2 mm. The present invention has no strict requirements on the drying method, and conventional methods in the art can be used. The present invention successively uses the large amount of NPK and other components in the composite fertilizer to encapsulate the core-shell structure, which has the advantage of allowing the fertilizer components to both play a fertilizer effect and act as an encapsulation layer.

[0032] After obtaining the fertilizer core particles, the present invention uses a carrier to coat the fertilizer core particles to obtain an inner-coated water-retaining slow-release fertilizer. As an embodiment, the coating method of the present invention includes: spraying the carrier on the surface of the fertilizer core particles and then drying. The present invention has no strict requirements on the drying method, and conventional methods in the art can be used.

[0033] After obtaining the inner film water-retaining slow-release fertilizer, the present invention uses microorganisms to coat the inner film water-retaining slow-release fertilizer to obtain a microorganism layer coated fertilizer. As an embodiment, the coating method of the present invention includes: spraying the microorganisms on the surface of the inner film water-retaining slow-release fertilizer; as another embodiment, the coating method of the present invention includes: spraying the microbial agent of the microorganism on the surface of the inner film water-retaining slow-release fertilizer. The present invention has no strict requirements on the source of the microorganism, and it can be obtained from commercially available products.

[0034] The microbial layer coated fertilizer is obtained. The present invention uses a double network hydrogel shell to wrap the microbial layer coated fertilizer to obtain a microbial fertilizer. As an embodiment, the encapsulation method of the present invention includes: heating the double network hydrogel shell at 60-80°C to obtain a molten hydrogel; soaking the microbial layer coated fertilizer with the molten hydrogel and then granulating. As an embodiment, the preparation method of the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel of the present invention includes: mixing gelatin, polyvinyl alcohol, water and glycerol, mixing evenly at 85-100°C, cooling to room temperature, keeping at -18°C for 12h, and then keeping at 25°C for 2h to obtain the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel.

[0035] The present invention also provides the use of the microbial fertilizer described in the above technical solution or the microbial fertilizer obtained by the preparation method in plant cultivation.

[0036] As an embodiment, the plant cultivation of the present invention includes stabilizing plant yield under adverse conditions and / or increasing yield under favorable conditions. As an embodiment, the plant of the present invention includes rapeseed. As an embodiment, the adverse conditions of the present invention include dry environments. The microbial fertilizer of the present invention has the effects of drought resistance, water retention, slow release, stabilizing yield under adverse conditions and increasing yield under favorable conditions, and can especially improve the yield and quality of rapeseed under dry environments.

[0037] In order to further illustrate the present invention, a microbial fertilizer with drought resistance, water retention and slow-release effect provided by the present invention, and its preparation method and application are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0038] Example 1 Synthesis of Nano-FeO4 The chemical coprecipitation method is used to synthesize nano-iron tetroxide. Specifically, Fe 2+ with Fe 3+ The molar ratio of Fe 2+ The aqueous solution was slowly added to the Fe 3+The aqueous solution was stirred continuously. The ammonia solution was dripped into the mixture at 50°C while maintaining the stirring state to obtain black nano-iron oxide particles. The mixture was stirred for 2 hours to allow the particles to grow. Finally, the supernatant was discarded by centrifugation, the precipitate was washed with deionized water, and vacuum dried to obtain iron oxide particles. The scanning electron microscopy characterization results showed that the particle size was 40~60nm ( Figure 1 ).

[0039] Example 2 Preparation of porous silica nanocarriers Solution A was obtained by mixing 6% v / v ammonia water, 34% v / v ethanol solution and 60% v / v water; solution B was obtained by mixing 10% v / v ethyl orthosilicate and 90% v / v ethanol solution. Solution A was injected into solution B under stirring and stirred for 2 hours. The sample obtained after centrifugation at 8000 r / min for 10 minutes was washed twice with ethanol and water respectively to obtain porous silica nanocarriers, which were dispersed in water for later use.

[0040] The prepared porous silica nanocarriers were characterized by scanning electron microscopy and transmission electron microscopy, respectively. Figure 2 and Figure 3 As shown. Figure 2 and Figure 3 It can be seen that the particle size of the prepared porous silica nanocarrier is about 300 nm, and there are abundant pores on the surface.

[0041] Example 3 Preparation of composite carrier of sodium carboxymethyl cellulose and sodium alginate Sodium carboxymethyl cellulose and sodium alginate (mass ratio of 1:1) were added to deionized water, and magnetic stirring was performed until the mixture was uniform. 0.1wt.% calcium chloride solution was added dropwise, and magnetic stirring was continued for 10-14h. The obtained sample was freeze-dried for 24h to obtain a sodium carboxymethyl cellulose-sodium alginate composite carrier, as shown in the schematic diagram. Figure 4 shown.

[0042] Example 4 Preparation of polyvinyl alcohol-propylene glycol / gelatin double network organohydrogel Water and propylene glycol are mixed in a volume ratio of 5.5:4.5 to obtain a solvent; gelatin and polyvinyl alcohol are added to the solvent, mixed evenly at 95°C, cooled to room temperature, and subjected to a freeze-thaw process (kept at -18°C for 12 hours, then kept at 25°C for 2 hours) to obtain a polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel; wherein the ratio of polyvinyl alcohol to gelatin is 6.5:3.5; and the total mass of the polyvinyl alcohol and gelatin accounts for 20% of the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel.

[0043] Example 5 Preparation of microbial fertilizer 1. Prepare the materials according to the following mass parts: the raw materials for preparing the microbial fertilizer include 2.5 parts of nano-ferroferric oxide obtained in Example 1, 2.5 parts of porous silica nanocarrier obtained in Example 2, 75 parts of compound fertilizer, 5 parts of sodium carboxymethyl cellulose and sodium alginate composite carrier obtained in Example 3, 10 parts of microbial preparation and 5 parts of polyvinyl alcohol-glycerol / gelatin double network organic hydrogel obtained in Example 4; Each mass part of compound fertilizer is composed of the following raw materials by mass parts: 20 parts of macroelement urea, 20 parts of monoammonium phosphate, 20 parts of potassium sulfate, 10 parts of trace elements, and 5 parts of humic acid; 2. Using the coprecipitation method, the porous silica nanocarrier obtained in Example 2 is used to load the nano-iron tetroxide obtained in Example 1 to obtain a core-shell structure; 3. Grind urea, monoammonium phosphate, potassium sulfate, trace elements and humic acid through a 40-100 mesh sieve, then mix the sieved urea, monoammonium phosphate and potassium sulfate evenly, enter the drum granulator, and pass the spray (atomized water) containing the core-shell structure obtained in step 2 for rolling humidification granulation. The granulation particle size is 1-2 mm, and then add the other raw materials that are sieved and mixed evenly, and continue granulation. Finally, take out the obtained particles, dry them, and obtain a fertilizer containing a nano-core-shell structure loaded with a nano-core and a synergistic nutrition compound (obtain fertilizer core particles); 4. Put the fertilizer core particles obtained in step 3 into a granulator, rotate the disc, spray the solution of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, take out, and dry to obtain an inner-encapsulated water-retaining slow-release fertilizer; 5. Use a coating machine spraying system to evenly spray the purchased microbial preparation (purchased from Shandong Hai Ruisi Marine Biotechnology Co., Ltd., including 1 part of Bacillus subtilis, 1 part of Bacillus laterosporus, 1 part of Bacillus licheniformis, 1 part of Bacillus thuringiensis, 1 part of Bacillus amyloliquefaciens, 1 part of Trichoderma harzianum, 1 part of Aspergillus oryzae and 1 part of Gliocladium roseum) on the surface of the inner coating water-retaining slow-release fertilizer obtained in step 4 to obtain a microbial layer coated fertilizer; 6. The hydrogen bonds of the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel obtained in Example 4 were interrupted by heating at 60-80°C to obtain a molten hydrogel; the microbial layer-coated fertilizer obtained in step 5 was soaked in the prepared molten hydrogel for 3-5 seconds and then taken out, and the granulation particle size was 3-5 mm to obtain a microbial fertilizer. The local scanning electron microscope image of the particle surface is as follows: Figure 5 As shown, the finished product is as follows Figure 6 shown.

[0044] Comparative Example 1 A preparation method of a microbial fertilizer is similar to that of Example 5 except that the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel is not used. The specific steps are as follows: 1. Prepare the following materials by mass: 2.5 parts of nano-ferroferric oxide obtained in Example 1, 2.5 parts of porous silica nanocarrier obtained in Example 2, 75 parts of compound fertilizer, 5 parts of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, and 10 parts of microbial preparation; Among them, each mass part of compound fertilizer includes 20 parts of macro-element urea, 20 parts of monoammonium phosphate, 20 parts of potassium sulfate, 10 parts of trace elements, and 5 parts of humic acid; 2. Using the coprecipitation method, the porous silica nanocarrier obtained in Example 2 is used to load the nano-iron tetroxide obtained in Example 1 to obtain a core-shell structure; 3. Grind urea, monoammonium phosphate, potassium sulfate, trace elements and humic acid through a 40-100 mesh sieve respectively, then mix the sieved urea, monoammonium phosphate and potassium sulfate evenly, put them into a drum granulator, and pass the spray (atomized water) containing the core-shell structure obtained in step 2 to perform rolling humidification granulation. The granulation particle size is 1-2 mm, and then add the other raw materials that have been sieved and mixed evenly, and continue granulation. Finally, take out the obtained particles and dry them to obtain the fertilizer core particles; 4. Put the fertilizer core particles obtained in step 3 into a granulator, rotate the disc, spray the solution of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, take out, and dry to obtain an inner-encapsulated water-retaining slow-release fertilizer; 5. Use the coating machine spraying system to evenly spray the purchased microbial preparation (purchased from Shandong Hairuisi Marine Biotechnology Co., Ltd.) on the surface of the inner coating water-retaining slow-release fertilizer obtained in step 4 to obtain microbial fertilizer.

[0045] Comparative Example 2 A method for preparing microbial fertilizer is similar to Example 5 except that polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel and nano-ferrous oxide are not used. The specific steps are as follows: 1. Prepare the following materials by weight: 2.5 parts of the porous silica nanocarrier obtained in Example 2, 75 parts of the compound fertilizer, 5 parts of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, and 10 parts of the microbial preparation; Among them, each mass part of compound fertilizer includes 20 parts of macro-element urea, 20 parts of monoammonium phosphate, 20 parts of potassium sulfate, 10 parts of trace elements, and 5 parts of humic acid; 2. Grind urea, monoammonium phosphate, potassium sulfate, trace elements, and humic acid through a 40-100 mesh sieve, then mix the sieved urea, monoammonium phosphate, and potassium sulfate evenly, and put them into a rotary drum granulator. Pass the spray (atomized water) containing the porous silica nanocarrier obtained in Example 2 to perform rolling humidification granulation. The granulation particle size is 1-2 mm, and then add the other sieved and evenly mixed raw materials mentioned above, and continue granulation. Finally, take out the obtained particles, dry them, and obtain the fertilizer core particles; 3. Put the fertilizer core particles obtained in step 2 into a granulator, rotate the disc, spray the solution of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, take out, and dry to obtain an inner-encapsulated water-retaining slow-release fertilizer; 4. Use the coating machine spraying system to evenly spray the purchased microbial preparation (purchased from Shandong Hairuisi Marine Biotechnology Co., Ltd.) on the surface of the inner coating water-retaining slow-release fertilizer obtained in step 3 to obtain microbial fertilizer.

[0046] Comparative Example 3 A method for preparing a fertilizer, which is similar to Example 5 except that the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel, nano-ferrous oxide and microbial preparation are not used, and the specific steps are as follows: 1. Prepare the following materials by weight: 2.5 parts of the porous silica nanocarrier obtained in Example 2, 75 parts of the composite fertilizer, and 5 parts of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3; Among them, each mass part of compound fertilizer includes 20 parts of macroelement urea, 20 parts of monoammonium phosphate, 20 parts of potassium sulfate, 10 parts of trace elements and 5 parts of humic acid; 2. Grind urea, monoammonium phosphate, potassium sulfate, trace elements and humic acid through a 40-100 mesh sieve, then mix the sieved urea, monoammonium phosphate and potassium sulfate evenly, put them into a rotary drum granulator, and pass the spray (atomized water) containing the porous silica nanocarrier obtained in Example 2 to perform rolling humidification granulation, the granulation particle size is 1-2 mm, and then add the other sieved and evenly mixed raw materials mentioned above, and continue granulation. Finally, take out the obtained particles, dry them, and obtain the fertilizer core particles; 3. Put the fertilizer core particles obtained in step 2 into a granulator, rotate the disc, spray the solution of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, take out, dry, and obtain the fertilizer.

[0047] Comparative Example 4 A method for preparing a fertilizer, which differs from Example 5 in that polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel, nano-ferrous oxide and microbial preparation are not used, and the composition of the compound fertilizer is different. The specific steps are as follows: 1. Prepare the following materials by weight: 2.5 parts of the porous silica nanocarrier obtained in Example 2, 70 parts of the composite fertilizer, and 5 parts of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3; Each mass portion of compound fertilizer includes 20 parts of macronutrient urea, 20 parts of monoammonium phosphate, 20 parts of potassium sulfate and 10 parts of trace elements; 2. Grind urea, monoammonium phosphate, potassium sulfate and trace elements through a 40-100 mesh sieve, then mix the sieved urea, monoammonium phosphate and potassium sulfate evenly, put them into a rotary drum granulator, and introduce a spray (atomized water) containing the porous silica nanocarrier obtained in Example 2 to perform rolling humidification granulation, with a granulation particle size of 1-2 mm, then add the sieved trace elements and continue granulation. Finally, take out the obtained particles, dry them, and obtain the fertilizer core particles; 3. Put the fertilizer core particles obtained in step 2 into a granulator, rotate the disc, spray the solution of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, take out, dry, and obtain the fertilizer.

[0048] Comparative Example 5 A method for preparing a fertilizer, which differs from Example 5 in that polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel, nano-ferrous oxide and microbial preparation are not used, and the composition of the compound fertilizer is different. The specific steps are as follows: 1. Prepare the following materials by weight: 2.5 parts of the porous silica nanocarrier obtained in Example 2, 60 parts of the composite fertilizer, and 5 parts of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3; Wherein, each mass part of compound fertilizer includes 20 parts of macro-element urea, 20 parts of monoammonium phosphate and 20 parts of potassium sulfate; 2. Grind urea, monoammonium phosphate, potassium sulfate and trace elements through a 40-100 mesh sieve respectively, then mix the sieved urea, monoammonium phosphate and potassium sulfate uniformly, put them into a rotary drum granulator, and introduce a spray (atomized water) containing the porous silica nanocarrier obtained in Example 2 to perform rolling humidification granulation, and the granulation particle size is 1-2 mm to obtain fertilizer core particles; 3. Put the fertilizer core particles obtained in step 2 into a granulator, rotate the disc, spray the solution of the composite carrier of sodium carboxymethyl cellulose and sodium alginate obtained in Example 3, take out, dry, and obtain the fertilizer.

[0049] Application Example 1 Effects of spreading microbial fertilizer on rapeseed growth This embodiment adopts the test method of planting rapeseed in a planting pot. The size of the planting pot is: pot mouth diameter 11.6 cm × pot bottom diameter 7.8 cm × pot height 9.6 cm. Each pot is filled with 0.5 kg of soil and sown. When the rapeseed grows to 2 true leaves, the seedlings are fixed, and one rapeseed is retained in each pot. During this period, water once every 2 days, about 200 mL of water each time. When it grows to the fifth true leaf stage, it is randomly divided into different treatment groups and fertilized with fertilizers of different components. Each treatment is set up with 5 parallel groups. The specific treatment method is as follows: Treatment 1: no fertilizer; Treatment 2: spreading the fertilizer obtained in Comparative Example 5; Treatment 3: spreading the fertilizer obtained in Comparative Example 4; Treatment 4: spreading the fertilizer obtained in Comparative Example 3; Treatment 5: spreading the fertilizer obtained in Comparative Example 2; Treatment 6: spreading the microbial fertilizer obtained in Comparative Example 1; Treatment 7: spreading the microbial fertilizer obtained in Example 5.

[0050] Each treatment group was harvested 21 days after treatment (fertilization was applied only once during the treatment period, and the watering frequency and amount in each pot were kept consistent). Figure 7 and Figure 8 As shown. Figure 7 and Figure 8 It can be seen that although the seedlings in each treatment group have different heights due to individual differences between the seedlings, it can be seen that from treatment 1 to treatment 7, the overall height of the seedlings shows an increasing trend; among them, Figure 7 and Figure 8 From left to right, they are process 1 to 7.

[0051] Application Example 2 Effects of spreading microbial fertilizer on rapeseed growth under water shortage conditions This embodiment adopts the test method of planting rapeseed in a planting pot. The size of the planting pot is: pot mouth diameter 11.6 cm × pot bottom diameter 7.8 cm × pot height 9.6 cm. Each pot is filled with 0.5 kg of soil and sown. When the rapeseed grows to 2 true leaves, the seedlings are fixed, and one rapeseed is retained in each pot. During this period, water once every 2 days, about 200 mL of water each time. When it grows to the fifth true leaf stage, it is randomly divided into different treatment groups and fertilized with fertilizers of different components. Each treatment is set up with 5 parallel groups. The specific treatment method is as follows: Treatment 1: no fertilizer; Treatment 2: spreading the fertilizer obtained in Comparative Example 5; Treatment 3: spreading the fertilizer obtained in Comparative Example 4; Treatment 4: spreading the fertilizer obtained in Comparative Example 3; Treatment 5: spreading the fertilizer obtained in Comparative Example 2; Treatment 6: spreading the microbial fertilizer obtained in Comparative Example 1; Treatment 7: spreading the microbial fertilizer obtained in Example 5.

[0052] (1) Each treatment group was harvested after 21 days of treatment (fertilization was applied only once during the treatment period, and the watering frequency was changed from once every 2 days to once every 5 days to simulate water shortage conditions). Fig. 9 shown.

[0053] according to Fig. 9 It can be seen that compared with other treatments (treatments 1-6), the seedlings in treatment 7 showed a more obvious drought resistance effect. This shows that the microbial fertilizer provided by the present invention can play a certain drought resistance and water retention effect.

[0054] (2) After harvest, rapeseed was first sampled in a fresh state to measure the contents of nitrogen, total phosphorus, vitamin C, total amino acids, H2O2, DPPH, superoxide anion, POD and other indicators. Then, it was placed in an oven at 105°C for 30 min, then dried in an oven at 75°C and ground. Finally, the rapeseeds treated with different methods were subjected to physical and chemical analysis. The results are shown in Table 1.

[0055] Table 1 Yield and quality of rapeseed in different treatments

[0056] It can be seen from Table 1 that from treatment 1 to treatment 7, the moisture content gradually increases, proving that the microbial fertilizer provided by the present invention can play a certain drought resistance and water conservation effect; the content of nitrogen, phosphorus and potassium elements gradually increases, indicating that the microbial fertilizer provided by the present invention can promote the absorption of fertilizer nutrients by crops to a certain extent; at the same time, the content of beneficial elements iron, manganese and zinc, vitamin C and total amino acid content in the seedlings also show an increasing trend, which shows that the microbial fertilizer provided by the present invention can improve the nutritional quality of the seedlings to a certain extent; the hydrogen peroxide content and the superoxide anion content show a decreasing trend, indicating that the microbial fertilizer provided by the present invention has a certain ability to scavenge free radicals (active oxygen); the DPPH and POD contents show an increasing trend, indicating that the microbial fertilizer provided by the present invention has a strong stress resistance effect.

[0057] It can be seen from the above content that the microbial fertilizer provided by the present invention can play the effects of drought resistance, water conservation, slow release, stable production in adverse conditions and increased production in favorable conditions.

[0058] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A microbial fertilizer with drought resistance, water retention and slow release effect, characterized in that: The microbial fertilizer includes, from the inside to the outside, a nanoenzyme with peroxidase activity, a mesoporous material, a compound fertilizer, a carrier, a microorganism and a double-network hydrogel shell; The compound fertilizer comprises a large amount of NPK elements, trace elements and synergistic components; The synergistic components include one or more of seaweed extract, humic acid, biochar, zinc humic acid, and selenoamino acid; The carrier comprises a sodium carboxymethyl cellulose-sodium alginate composite carrier; The effective viable count of the microorganisms is ≥ 20-50 million / gram, and includes Bacillus subtilis, Bacillus laterosporus, Bacillus licheniformis, Bacillus thuringiensis, Bacillus amyloliquefaciens, Trichoderma harzianum, Aspergillus oryzae and Gliocladium roseum.

2. The microbial fertilizer according to claim 1, characterized in that: The microbial fertilizer comprises the following components in parts by weight: 1-5 parts of nanoenzymes with peroxidase activity, 1-5 parts of mesoporous materials, 60-80 parts of compound fertilizers, 1-5 parts of carriers, 2-10 parts of microorganisms and 2-10 parts of double-network hydrogel shells.

3. The microbial fertilizer according to claim 2, characterized in that Each portion of the compound fertilizer includes the following components by mass: 50-60 portions of macroelement NPK, 5-10 portions of trace elements, and 5-10 portions of synergistic components; Each portion of the microorganism comprises the following components in parts by mass: 1-2 parts of Bacillus subtilis, 1-2 parts of Bacillus laterosporus, 1-2 parts of Bacillus licheniformis, 1-2 parts of Bacillus thuringiensis, 1-2 parts of Bacillus amyloliquefaciens, 1-2 parts of Trichoderma harzianum, 1-2 parts of Aspergillus oryzae and 1-2 parts of Gliocladium roseum; The mass ratio of sodium carboxymethyl cellulose to sodium alginate in the carrier is (1-5): (1-5).

4. The microbial fertilizer according to claim 2, characterized in that: The nanozyme having peroxidase activity comprises ferrosoferric oxide; The mesoporous material includes one or more of mesoporous silica, LDHs and mesoporous silica; The double network hydrogel shell comprises polyvinyl alcohol-glycerol / gelatin double network organic hydrogel.

5. The microbial fertilizer according to claim 4, characterized in that: The polyvinyl alcohol-glycerol / gelatin double network organic hydrogel comprises water, glycerol, polyvinyl alcohol and gelatin; The mass ratio of water to glycerol in the polyvinyl alcohol-glycerol / gelatin double network organic hydrogel is (4-9): (1-6); The mass ratio of polyvinyl alcohol to gelatin in the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel is (5-9): (1-5); The total mass of the polyvinyl alcohol and gelatin accounts for 15-35% of the polyvinyl alcohol-propylene glycol / gelatin double network organic hydrogel.

6. The microbial fertilizer according to any one of claims 1 to 5, characterized in that The dosage form of the microbial fertilizer is granules.

7. The method for preparing the microbial fertilizer according to any one of claims 1 to 6, characterized in that: The steps include: Nanozymes with peroxidase activity were loaded on mesoporous materials to obtain core-shell structures; The core-shell structure is encapsulated by using a compound fertilizer, granulated, and dried to obtain fertilizer core particles; The core particles of the fertilizer are coated with a carrier to obtain an inner-coated water-retaining slow-release fertilizer; The inner film water-retaining slow-release fertilizer is coated with microorganisms to obtain a microorganism layer coated fertilizer; The microbial layer-coated fertilizer is wrapped by a double-network hydrogel shell to obtain a microbial fertilizer.

8. The preparation method according to claim 7, characterized in that: The loading method includes co-precipitation method and / or Stöber method; The encapsulation method comprises: mixing and granulating the macroelement NPK in the compound fertilizer and the core-shell structure, and then mixing and granulating with other components in the compound fertilizer; The coating method comprises: spraying the carrier on the surface of the fertilizer core particles and then drying; The coating method comprises: spraying microorganisms on the surface of the inner-encapsulated water-retaining slow-release fertilizer; The encapsulation method comprises: heating the double network hydrogel shell at 60-80° C. to obtain a molten hydrogel; and granulating the fertilizer by soaking the microorganism layer in the molten hydrogel.

9. Use of the microbial fertilizer according to any one of claims 1 to 6 or the microbial fertilizer obtained by the preparation method according to claim 7 or 8 in plant cultivation.

10. The use according to claim 9, characterized in that: The plant cultivation includes stabilizing plant yield under adverse conditions and / or increasing plant yield under favorable conditions.

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