36 results about "Inorganic nutrient" patented technology

The invention provides a microbial agent type bio-organic fertilizer capable of improving continuous cropping tobacco planting soil hardening and a preparation method of the microbial agent type bio-organic fertilizer, and belongs to the technical field of organic fertilizers. The microbial agent type bio-organic fertilizer capable of improving continuous cropping tobacco planting soil hardening comprises the following raw materials: an organic material, a microbial agent, an inorganic nutritional ingredient, vinasse and an additive, wherein the organic material is composed of livestock and poultry manure, crop straw, tobacco waste and a fermentation inoculant; the additive is prepared from humic acid, seaweed extract and amino acid. The organic fertilizer contains rich organic materials and humic acid, the content of organic matters in soil can be increased, the granular structure of the soil can be improved, the growth of soil-borne pathogenic bacteria can be inhibited by the added multiple beneficial microorganisms, the micro-ecological environment of the soil can be improved by the photosynthetic bacteria, and the incidence rate of diseases such as tobacco black shank and bacterial wilt can be reduced.

The invention relates to the technical field of compound fertilizers, and discloses a compound fertilizer with long-acting slow release and accurate oxygen supply functions and a preparation method thereof, and the compound fertilizer comprises 35-40 parts of an organic waste base material, 20-30 parts of inorganic nutrients, 5-8 parts of a binder, 2-4 parts of medium trace elements, 4-6 parts of humic acid, 2-4 parts of sodium carboxymethyl cellulose, 3-5 parts of chitosan and 3-5 parts of sodium alginate. According to the invention, chitosan and sodium alginate are adopted to form a double-layer coating on the surfaces of fertilizer particles, the outer sodium alginate forms a film with certain permeability, firstly, the film has a barrier effect on fertilizer nutrients and delays the diffusion speed of the nutrients into soil, the inner chitosan further regulates and controls nutrient release, and the chitosan and the sodium alginate have a synergistic effect, so that the slow release of the nutrients is realized. The nutrient release period is greatly prolonged, so that fertilizer nutrients can be continuously and stably supplied to soil, the problem of rapid nutrient loss after one-time fertilization is reduced, and lasting nutrient support is provided for crop growth.

The invention relates to the field of agricultural fertilizers and particularly provides a compound fertilizer for increasing the content of organic matters in soil and a preparation process thereof. The fertilizer comprises a humic acid activation carrier, a biochar-based material, a microbial agent, nitrogen-phosphorus-potassium inorganic nutrients and a coated controlled release agent. Through synergistic modification of humic acid and biochar, the stability of organic matters is enhanced, nutrient slow release is realized in combination with the decomposition effect of microbial flora on organic matters and a coating controlled release technology, and the accumulation efficiency of soil organic matters is remarkably improved. After being applied, the fertilizer can improve the granular structure of soil, improve microbial activity and reduce fertilizer loss, and is suitable for improving organic matter barren soil.

The invention relates to the technical field of seed pelleting processing, in particular to an alfalfa seed pelleting material and a preparation method of alfalfa seed pellets. Through scientific compatibility and synergistic effects in a pill coating material system, the water-retaining agent guarantees a moisture basis, the microbial agent constructs a biological barrier and promotes conversion, the inorganic nutrients provide material support, and the bioactive substances stimulate intrinsic potentials and synergistically act on the alfalfa seed germination physiological process, so that the alfalfa seed germination rate is increased, and the alfalfa seed germination rate is increased. Finally, the technical effects of remarkably promoting the germination rate and uniformity of the seeds and improving the nodulation rate are achieved, and a solid foundation is laid for developing high-quality and high-yield alfalfa seeds.

The application discloses an improved plant liquid culture medium, which comprises inorganic nutrients required by plant basic growth and does not comprise compounds containing an EDTA ligand skeleton and iodide. The application also discloses application of the improved plant liquid culture medium in mercury compound metabolism research. The application is based on the technical problem of finding that a culture medium substrate mediates abiotic transformation and causes error defects, and by eliminating the compounds containing the EDTA ligand skeleton and the iodide which induce abiotic transformation of mercury compounds, the application is applied to block the abiotic transformation path of methyl mercury in the mercury compound metabolism research, and eliminate the 'false positive' error in the metabolism research.

The application belongs to the technical field of fertilizers, and particularly relates to a yeast-source biological organic fertilizer suitable for aquaculture and a preparation method and application thereof. The yeast-source biological organic fertilizer suitable for aquaculture comprises the following components in parts by weight: 40-80 parts of yeast metabolites, 15-30 parts of ammonium chloride, 10-20 parts of monoammonium phosphate and 3-8 parts of a compound microbial agent. The yeast-source biological organic fertilizer suitable for aquaculture has reasonable proportioning, a high number of beneficial bacteria, a good symbiotic environment of multiple bacteria and strong biological activity. The organic active nutrients, effective microbial groups and inorganic nutrients are complete and scientifically proportioned, and the fertilizer has good effects of fertilization, water culture and algae cultivation, can improve the aquaculture water environment, supplement feed organisms, promote the growth of aquaculture objects, improve product benefits and is more conducive to environmental protection.

The invention relates to a spraying granulation fertilizer, a preparation method and application thereof, and the preparation method comprises the following steps: S1, mixing weathered coal or lignite, potassium hydroxide and lignin liquid, and carrying out fermentation reaction in an alkaline environment to obtain active primary pulp rich in potassium fulvate; s2, mixing the active raw stock obtained in the step S1 with a nitrogen source, a phosphorus source, a potassium source, a medium element compound and a trace element compound according to a ratio, grinding into slurry, and reacting under an alkaline or neutral condition, so that inorganic nutrients and fulvic acid radicals in the active raw stock are preliminarily integrated; s3, adding an acidity regulator into the slurry after the reaction in the step S2, regulating the pH value of the slurry to a weak acidic range of 5.5-7.0, and carrying out a reaction, so that all components in the slurry form a stable water-soluble complex structure under a weak acidic condition; and S4, carrying out spraying granulation on the slurry reacted and filtered in the step S3 at 1000-1200 DEG C to obtain the granular fertilizer.

The invention discloses a special compound microbial fertilizer for melons, fruits and vegetables and a preparation method thereof. The fertilizer is prepared from kitchen garbage, chicken manure, straw powder, inorganic nutrients, a compound microbial agent, a lignin degrading microbial agent, potassium humate, a trace element additive, charcoal and a functional binder according to a specific proportion. The preparation method comprises the steps of raw material pretreatment, primary mixing and tempering, primary aerobic fermentation, screening, secondary anaerobic fermentation, nutrient blending, granulation and film coating, particle screening and packaging, and quality detection and storage. Through the synergistic effect of the components in the formula and the optimization process of the two-stage fermentation and coating technology, the fertilizer disclosed by the invention remarkably improves the yield and quality of melons, fruits and vegetables, improves the soil structure, enhances the microbial activity, prolongs the fertilizer efficiency and reduces the nutrient loss. The technology adopts intelligent equipment, is green and efficient, and is suitable for industrial production and fruit and vegetable planting.

The invention discloses a modified bio-based coated controlled-release fertilizer and a preparation method thereof, and belongs to the technical field of bio-organic fertilizers. The fertilizer comprises two parts, namely a coating prepared from a modified bio-based coating material and a fertilizer core prepared from organic and inorganic nutrient substances. The modified bio-based material is used as the coating layer, so that the slow release performance of the fertilizer is remarkably improved, and the problem of environmental pollution caused by a traditional petroleum-based polymer coating material is effectively solved. The natural biomass material is chemically modified, so that the mechanical strength and water resistance of the coating material are improved, and meanwhile, good biodegradability is reserved. Agricultural wastes such as pineapple leaves are efficiently utilized, so that cyclic utilization of resources is realized, and the pressure of the wastes on the environment is also reduced. Compared with the prior art, the degradation speed of the fertilizer in soil is more balanced, and potential damage to the soil structure can be avoided while the slow release effect is guaranteed.

The present application relates to the technical field of inorganic fiber matrix, and discloses a kind of inorganic fiber matrix for sand control and preparation method, comprising the following steps: S1, preparation inorganic nutrient solution, water, ammonium nitrate, potassium dihydrogen phosphate, potassium sulfate and magnesium sulfate are mixed uniformly, obtain nutrient solution;S2, preparation medicament, antagonistic bacteria, bacillus subtilis, trichoderma harzianum and gram actinomycetes group are mixed, after mixing, the nutrient solution obtained in S1 step is added, and continue to mix until uniform.The present application is formed in the form of large pore by inorganic fiber matrix material as a whole, root system can pass through large pore and come out from the bottom and four of inorganic fiber matrix, and then fully wrap inorganic fiber matrix, using the high water absorption of inorganic fiber matrix, can swell and absorb water when watering, achieve the characteristics of good root water absorption effect, when plant growth, can continuously absorb the moisture of inorganic fiber pore, achieve the effect of good water retention, and then improve the survival rate of plant.

The invention discloses a microbial compound fertilizer and application thereof in perennial rice planting, and belongs to the technical field of microbial compound fertilizers. The microbial compound fertilizer is prepared from the following raw materials: a compound microbial flora consisting of brevibacillus laterosporus, pseudomonas fluorescens, azospirillum brasilense, soil bacillus and paecilomyces lilacinus. The microbial compound fertilizer provided by the invention can significantly improve the yield of perennial rice and soil health through organic-inorganic nutrient coordination and functional microbial community regulation and control, and is suitable for a perennial rice continuous cropping planting scene. The microbial compound fertilizer provided by the invention solves the problems of soil nutrient imbalance, root development limitation and the like in the planting process of perennial rice, and provides technical support for further improving the yield and production benefit of perennial rice.

The invention relates to the technical field of fertilizer preparation, in particular to a fertilizer containing a natural insect repelling component and a preparation method thereof.The fertilizer is prepared from, by weight, 20-80 parts of an organic matrix, 0.5-10 parts of the natural insect repelling component, 3-35 parts of an inorganic nutrient component, 0.05-2.0 parts of a microbial agent, 0.05-1.0 part of beauveria bassiana and 0.1-6 parts of auxiliaries; the natural parasite expelling components and the beauveria bassiana are compounded to form a synergistic parasite expelling system, and the parasite expelling system, the organic matrix, the inorganic nutrient components, the microbial agent and the auxiliaries have a synergistic effect, so that integration of parasite expelling, nutrient supply and soil improvement is realized.

The application discloses a slow-release biochar-based compound fertilizer and a production process thereof, and belongs to the technical field of biochar-based fertilizers.The compound fertilizer comprises, in terms of weight parts, modified biochar 30-45 parts, inorganic nutrient raw material 50-65 parts, composite cross-linking binder 4-10 parts and chelated trace elements 1-3 parts;the production process comprises, in sequence, biochar micropore cleaning and activation, free radical oxidation modification, surface grafting polymerization, vacuum impregnation loading and cross-linking embedding granulation;the application increases oxygen-containing functional groups on the surface of biochar and constructs hierarchical pore structures through an oxalic acid-assisted catalytic free radical oxidation system and a maleic anhydride-itaconic acid double monomer grafting technology;through modification of biochar and in combination with a vacuum loading process, nutrients are locked inside the hierarchical pores, and then, a moisture-responsive binder coating is supplemented, so that double synergistic slow release of nutrients is realized, the problems of loose nutrient loading, easy loss and short slow-release period of existing carbon-based fertilizers are solved, and the application is especially suitable for saline-alkali soil improvement and dry farming.

The invention relates to the technical field of organic-inorganic complex microbial inoculant manufacturing, and discloses a synergistic interaction type organic-inorganic complex microbial inoculant for promoting rice yield increase and a preparation method thereof.The preparation method comprises the steps that an organic carrier is subjected to pH adjustment to form an active interface with negative charges, then two multivalent metal cations with different coordination capacities are adopted to construct a gradient stable structure, and the gradient stable structure is formed; microorganisms and inorganic nutrients are jointly anchored on an interface in situ in an ion bridge form, and finally, low-temperature solidification is performed, and through a chemical structure pre-constructed in a manufacturing stage, each functional component forms an inseparable synergistic unit, so that functional dissociation and action opportunity mismatch caused by physical scouring of the functional components in soil are avoided, and the soil remediation efficiency is improved. And an internal response relationship between nutrient supply and microorganism demand is established.

The invention belongs to the field of agricultural waste recycling, and discloses a slow-release compound fertilizer prepared by utilizing a camellia oleifera shell cell structure, and a preparation method of the slow-release compound fertilizer comprises the following steps: removing impurities to obtain a camellia oleifera shell raw material, crushing, drying to obtain a shell base material, fully dipping in molten urea, filtering, and cooling to obtain the compound fertilizer. The compound fertilizer disclosed by the invention is simple in whole preparation process, high in repeatability and relatively low in equipment requirement. The compound fertilizer has high application value in the agricultural field, the added value of the camellia oleifera shells can be remarkably improved, and the economic income of farmers is increased. Due to the remarkable structural difference between parenchyma cells and thick-walled cell walls of the camellia oleifera shells, the prepared organic and inorganic nutrient slow-release compound fertilizer can efficiently store urea without additional high-temperature carbonization pore-forming, on the other hand, the high-temperature molten urea can react with hemicellulose carboxyl functional groups of the camellia oleifera shells to realize fixation of nitrogen, and the nitrogen fixation effect is improved. Therefore, intelligent release of nutrients is further realized to promote crop growth.

The invention relates to the technical field of aquaculture, and provides an algal phase regulator as well as a preparation method and application thereof. Active substances of yeast metabolites are compounded with composite inorganic nutrient elements, growth of beneficial algae for improving aquaculture water quality is promoted, stable algal phase and good water quality of aquaculture water are maintained, health and high efficiency of aquaculture production are guaranteed, the cost is low, and the effect is good.

The invention discloses a preparation method of a disease-resistant insect-proof bio-organic fertilizer, and relates to the field of agricultural biotechnology and novel fertilizers, and the preparation method comprises the following steps: pre-blending raw materials: respectively preparing a decomposed organic matter carrier, a composite inorganic nutrient bag, a composite functional microbial agent, a response type coating material and an induction activation solution; according to the invention, a space-time responsive core is constructed, an activated nutrition layer is prepared by adopting an ultrasonic wave and high-pressure homogenization technology, and efficient protection and targeted release of beneficial microorganisms and nano-scale homogeneous fusion of nutrients and functional components are realized through a structured assembly and programmed gradient drying process; according to the biological organic fertilizer disclosed by the invention, the stability, the durability and the accuracy of the disease-resistant and insect-proof effects of the biological organic fertilizer are remarkably improved, and meanwhile, the environmental adaptability and the crop rhizosphere colonization efficiency of the biological organic fertilizer are enhanced.

This invention discloses a biofilm-forming microbial consortium with acrylonitrile degradation function, its preparation method, and its application. The microbial consortium consists of *Agrobacterium parakneissus*, *Burkholderia szechuanensis*, *Trichophyton spp.*, *Rhodococcus rubrum*, and *Mycobacterium tumefaciens*; the ratio of viable bacteria of *Burkholderia parakneissus*, *Burkholderia szechuanensis*, *Trichophyton spp.*, *Oligotrophomonas spp.*, and *Trichophyton spp.* is 3:1:1:1:1. This microbial consortium has a stable microbial community structure and can rapidly form a stable biofilm on the surface of biofilter packing material, exhibiting high acrylonitrile degradation efficiency. It is simple to operate, low in cost, and requires only a small amount of additional inorganic nutrients during treatment, without causing secondary pollution, making it an environmentally friendly technology. Its application prospects in the treatment of acrylonitrile-containing wastewater (gas) are broad.

The invention discloses a biological liquid organic fertilizer and a preparation method thereof, and belongs to the technical field of agricultural fertilizers. The preparation method comprises the following steps: uniformly mixing livestock manure, livestock breeding wastewater, molasses, magnesium sulfate, monopotassium phosphate and modified charcoal to obtain slurry; carrying out microwave hydrothermal reaction on the slurry, then adding a microbial agent and xanthan gum into a reaction system, uniformly stirring, fermenting and sub-packaging to obtain the biological liquid organic fertilizer. The zeolite can lock inorganic nutrients, the humic acid is also an organic nitrogen source, and the zeolite and the humic acid are combined on a biochar framework, so that more long-acting nutrient slow release can be realized, the soil fertility is improved, and the yield increasing effect is realized; and moreover, efficient resource utilization of livestock and poultry breeding wastes is realized, the production process is green and environment-friendly, and the obtained product has both economic benefits and environmental benefits.

The invention discloses an organic fertilizer prepared from cane molasses fermentation liquor and application of the organic fertilizer in eucalyptus planting, and belongs to the technical field of agricultural resources and environments. The organic fertilizer is prepared by taking concentrated cane molasses fermentation liquor as a main raw material and matching with organic carriers such as bagasse and filter mud and inorganic nutrients of nitrogen, phosphorus and potassium; three functional components are creatively added: a nano-scale eucalyptus nutrition targeted delivery agent modified by silanization and root signal molecules, a controlled release carrier formed by compounding polysaccharide and mineral substances, and a chelate of biostimulant and trace elements. The components have a synergistic effect, so that the nutrient utilization efficiency is remarkably improved, the special requirements of eucalyptus on trace elements such as boron and zinc are met, and meanwhile, the soil structure is improved. According to the invention, the resource high-value utilization of the molasses fermentation liquor is realized, and the prepared organic fertilizer has the advantages of controllable nutrient release, strong targeting property and good soil improvement effect, and is especially suitable for eucalyptus cultivation.

The invention relates to the technical field of fertilizer manufacturing, and discloses a preparation method of an organic-inorganic compound fertilizer containing high-activity urea formaldehyde, which comprises the following steps: mixing and adsorbing a high-activity urea formaldehyde wet material with the water content of 45-60% and the solid content of 40-55% and a composite carrier containing modified biomass charcoal, humic acid and bentonite, and constructing a sealing layer at the orifice of the modified biomass charcoal; the premixed composite material and inorganic nutrient raw materials are mixed and granulated, and heat transfer retardation of a sealing layer is matched with latent heat of water evaporation, so that the interior of the carrier is kept at low temperature to limit thermal decomposition of high-activity components; according to the method, by means of a carrier shielding and moisture latent heat balance mechanism, the problem of property attenuation of high-activity urea formaldehyde at the granulation high temperature is solved, and synergistic enhancement of nutrient long-acting property and particle strength is achieved.

The invention relates to the technical field of agriculture, and discloses an organic-inorganic compound fertilizer for improving sandy soil and a preparation method of the organic-inorganic compound fertilizer. Comprising the following raw materials in parts by weight: 10-25 parts of humic acid, 20-40 parts of organic compost, 10-30 parts of plant residues, 1.5-5 parts of ammonium nitrate, 1-3 parts of monopotassium phosphate, 1.5-4 parts of potassium chloride, 0.5-2 parts of calcium oxide, 0.3-1 part of magnesium oxide, 0.5-3 parts of nitrogen-fixing bacteria, 0.5-3 parts of phosphate solubilizing bacteria, 0.5-3 parts of growth promoting microorganisms, 5-20 parts of natural mineral materials, 2-10 parts of biodegradable polymers and 0.1-0.3 part of zinc sulfate. Organic components and inorganic nutrients are combined and matched with the slow release effect of the natural mineral material and the biodegradable polymer, so that the nutrients in the fertilizer can be continuously released in soil, the situation that the nutrients are quickly consumed in a short time is avoided, and the phenomenon that the nutrients are rebounded after being effective in a short time is effectively avoided.

The invention relates to the technical field of special fertilizers for tobaccos, in particular to a special organic-inorganic water-soluble fertilizer for tobaccos and a preparation method thereof.The special organic-inorganic water-soluble fertilizer for tobaccos comprises a base fertilizer and an additional fertilizer, the base fertilizer and the additional fertilizer are combined, water-soluble organic matter and inorganic nutrients are scientifically proportioned, and it is ensured that the fertilizer can comprehensively meet the nutritional requirements of tobacco growth; the water solubility of the special fertilizer for tobacco is improved, the fertilizer can be quickly dissolved in water by optimizing the formula of the fertilizer and adding the auxiliary agent with a specific effect, and the absorption and utilization rate of the fertilizer is improved; by adopting an advanced production process, the stability and activity of the special fertilizer for tobacco are enhanced, the performance stability of the special fertilizer for tobacco in the storage and application process is ensured, and meanwhile, by adding active ingredients such as biostimulant, the fertilizer efficiency of the fertilizer and the promotion effect on tobacco growth are further improved.

This application discloses a bio-compound fertilizer and its preparation method, belonging to the field of organic fertilizer technology. The bio-compound fertilizer consists of inorganic nutrient components, synergistic components, compound functional microbial agents, and modified coating components. This application prepares a modified coating by blending polyacrylic acid and polyβ-hydroxybutyrate, and adding sodium alginate and nano-silica for modification. This coating can precisely respond to changes in rhizosphere pH and nutrient concentration to regulate nutrient release. This invention can achieve stable retention of live microorganisms and intelligent controlled nutrient release, is suitable for various crops and adverse soil conditions, and solves the pain points of existing products such as live bacteria inactivation and nutrient release imbalance, making it suitable for large-scale agricultural planting.

A process for preparing a composition comprising biomass from Aspergillus and bioactive compounds, the process including culturing Aspergillus in a liquid medium comprising an assimilable carbon source and inorganic nutrients. The culturing process includes (i) a fermentation under aerobic conditions followed by (ii) a fermentation under stress conditions comprising hypoxic stress and pH stress conditions. Compositions obtainable by this process and food or feed supplements containing the compositions are also provided.

The invention relates to the technical field of ecological restoration, in particular to modified coal gangue-based artificial soil for ecological restoration of a waste dump. The fertilizer is prepared from the following components: modified coal gangue, fly ash, a compound microbial agent, an organic nutrient medium, modified bentonite, humic acid, quick lime, a nitrogen-phosphorus-potassium compound fertilizer, a microelement fertilizer, sodium carboxymethyl cellulose and a microbial protective agent. The coal gangue is subjected to a physical crushing and chemical weathering simulation synergistic modification process, the coal gangue forms reasonable grain composition through physical crushing, the powder builds a stable inorganic framework for artificial soil, a citric acid-phosphoric acid-EDTA-2Na composite modifier solution dissolves insoluble minerals in the coal gangue through the acid dissolution effect, and the water content of the coal gangue is reduced; inorganic nutrients in the coal gangue are activated through complexation, and the surface activity and nutrient release capacity of the coal gangue are improved, so that the problems that the original coal gangue is low in surface activity and poor in fertilizer and water retention capacity are solved, and a core base material foundation is laid for artificial soil.

The invention relates to the technical field of fertilizer processing, in particular to a nutritional functional granulated fertilizer and a preparation method and application thereof. Comprising organic nutrients and inorganic nutrients; the inorganic nutrient is prepared from the following raw materials in parts by weight: 12 to 15 parts of urea, 12 to 15 parts of ammonium sulfate, 15 to 20 parts of monoammonium phosphate, 22 to 27 parts of potassium nitrate, 1.2 to 1.5 parts of calcium nitrate, 1.2 to 1.5 parts of magnesium sulfate, 1.0 to 1.2 parts of ferrous sulfate, 1.0 to 1.2 parts of zinc sulfate and 1.0 to 1.2 parts of borax; the organic nutrient is prepared from the following raw materials in parts by weight: 6 to 10 parts of glutamic acid, 5 to 9 parts of glycine, 7 to 10 parts of polyacrylamide, 1 to 4 parts of modified starch, 2 to 5 parts of soybean extract, 3 to 8 parts of rice bran extract, 2 to 6 parts of polyvinyl alcohol, 3 to 15 parts of biological enzyme and 10 to 25 parts of functional strains, and the functional strains are bacillus licheniformis NCT-1 and pediococcus pentosaceus.

The invention relates to the technical field of organic fertilizers, in particular to a needle mushroom residue-based fermented organic fertilizer for watermelon planting and a preparation method thereof, the needle mushroom residue-based fermented organic fertilizer comprises needle mushroom residues, modified vegetable oil residues, compound bacterial powder, functional auxiliary materials, humic acid and inorganic nutrient elements; through reasonable proportioning of the components and process optimization, multiple effects are realized: on one hand, agricultural wastes such as the needle mushroom dregs and the pleurotus eryngii dregs are used as raw materials, so that resource recycling is realized, and the production cost of the fertilizer is reduced; on the other hand, through the synergistic effect of all the components, comprehensive nutrient supply needed by watermelon growth is guaranteed, the fertilizer utilization rate is increased, the soil structure can be improved, the soil micro-ecological environment can be adjusted, and the soil fertility can be enhanced; meanwhile, the use of chemical fertilizers is reduced, the risk of environmental pollution is reduced, the planted watermelon fruits are excellent in quality and good in taste, and an effective solution is provided for green planting of watermelons.

This invention relates to the field of organic-inorganic composite microbial agent manufacturing technology, and discloses a synergistic organic-inorganic composite microbial agent for promoting rice yield and its preparation method. The method includes: forming a negatively charged active interface by adjusting the pH of an organic carrier; constructing a gradient stable structure using two multivalent metal cations with different coordination abilities; anchoring microorganisms and inorganic nutrients in situ at the interface in the form of ion bridges; and finally solidifying at low temperature. This invention, through the pre-constructed chemical structure during the manufacturing stage, enables each functional component to form an indivisible synergistic unit, thereby avoiding functional dissociation and mismatch of action timing caused by physical erosion in the soil, and establishing an intrinsic response relationship between nutrient supply and microbial demand.

The invention belongs to the field of agricultural fertilizers, and provides a slow-release NPK mixed fertilizer and a preparation method thereof. According to the invention, a design that a core-shell structure is formed by coating NPK inorganic nutrient matrix particles with a cross-linked organic-inorganic composite shell layer is adopted, and the NPK inorganic nutrient particles are used as a matrix and are coated with an organic-inorganic cross-linked shell layer formed by compounding a multi-carboxyl natural polymer, nano-silica and calcium ions; calcium ions and carboxyl form an ionic cross-linked network, so that the shell layer is moderately swelled in water and generates a continuous permeation channel, and the cumulative release rate of nitrogen in 90 days reaches 70-90%; in the shell layer, nano silicon dioxide is in gradient distribution in the mass ratio of the inner layer to the outer layer, the rheological property of the slurry and a spray atomization process window are both considered, the compressive strength of a single particle is larger than or equal to 20 N, and an anti-caking aid is added to the surface to prevent caking during storage and transportation without affecting the long-acting release performance. The preparation process is controllable, slow release and mechanical properties are both considered, and the preparation method has good application and popularization values.