Multilayer solid carbon source pesticide fertilizer, preparation method and application

Abstract

The invention discloses a multilayer solid carbon source medical fertilizer, a preparation method and application, and belongs to the field of agricultural medical fertilizers, the medical fertilizer is of a core-shell structure, and the medical fertilizer sequentially comprises an organic fertilizer core layer, a pesticide layer and a biostimulant layer from inside to outside; the organic fertilizer core layer contains organic fertilizer, the pesticide layer contains chlorantraniliprole and clothianidin, and the biostimulant layer contains humic acid substances. Through ordered release of the three layers of pesticide fertilizers, function synergy of'rhizosphere stimulation-pesticide release regulation and control-long-acting oxygen supply 'of the pesticide fertilizers is realized, the control effect and durability of the pesticide are promoted, meanwhile, pesticide injury is prevented, the absorption capacity and stress resistance of sugarcane are improved, and growth of the sugarcane and soil health are regulated and controlled.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizers and pesticides, and in particular to a multilayer solid carbon source fertilizer and pesticide, its preparation method, and its application. Background Technology

[0002] Sugarcane is an important sugar crop and economic crop in my country. Its long growth cycle and continuous, high nutrient demand throughout its growth stage result in a "predatory" absorption of soil nutrients. Furthermore, its root exudates and stubble residues easily lead to soil nutrient imbalances, soil compaction, and the accumulation of harmful substances. At the same time, sugarcane is constantly threatened by various pests and diseases, with sugarcane borers (mainly including striped stem borers, yellow stem borers, and two-spotted stem borers) being the most serious. Sugarcane borer larvae bore into the stalks, causing "dead hearts" during the seedling and tillering stages, and "bored nodes" during the elongation stage, directly leading to reduced sugarcane yield, lower sugar content, and even lodging.

[0003] For the control of sugarcane borers, the existing combination of chlorantraniliprole and thiamethoxam has a good effect on the control of sugarcane borers. However, the damage caused by the borers is long-term during the sugarcane growth cycle, and the existing agents only have a good effect for a short period of time. Sugarcane farmers often need to apply the pesticides multiple times to kill them. Moreover, the above-mentioned pesticides, especially chlorantraniliprole, are extremely difficult to dissolve in water, making it difficult to play a role, and they are very easy to be washed away by water, resulting in waste.

[0004] Furthermore, to achieve the control of sugarcane borers and the adequate supply of fertilizer nutrients, traditional methods of multiple fertilizations and separate pesticide applications are often adopted, along with the use of physically mixed or simply coated fertilizer and pesticide products. Traditional methods require multiple field operations during key growth stages such as the seedling stage, tillering stage, and elongation stage, which are labor-intensive and costly.

[0005] Existing pesticide-fertilizer products (such as patents CN116730763A and CN120167453A) combine pesticides and fertilizers, which reduces labor to some extent, but also have some limitations: (1) Most products are simply a combination of fertilizer and pesticide. The release of pesticides often reaches its peak rapidly in the early stage, which cannot accurately match the changing nutritional needs and pest occurrence patterns during the sugarcane growth period (such as the peak of stem borer damage in the early tillering and elongation stages). Moreover, it is easy to exceed the crop tolerance threshold and cause pesticide damage during the sugarcane seedling stage. (2) The production process is mostly simple physical mixing and granulation or single-layer coating. In the high temperature and high humidity sugarcane field environment, chemical reactions or physical separation may occur between the components, resulting in the decay of pesticide and fertilizer effects before application. (3) The duration of pesticide and fertilizer efficacy is generally short, which is difficult to cover the long growth cycle of sugarcane. In order to achieve full-process control and nutrient supply, multiple applications are still required in actual production, which fails to fundamentally save labor. (4) Existing products are simply a combination of pesticides and fertilizers. The release curves of their nutrient components and pesticide active components are highly similar and uncontrollable, and there is no synergistic effect. (5) Long-term continuous cropping of sugarcane is prone to soil fertility decline. The high concentration of fertilizer and pesticide components in existing fertilizers and pesticides will further inhibit soil microbial activity, accelerate soil acidification and compaction, damage soil ecological function, seriously restrict the quality and yield of sugarcane, and threaten the sustainability of the industry.

[0006] In summary, existing fertilizer-pesticide combination methods are merely physical additions of fertilizer and pesticides. Pesticides are often released rapidly, making it difficult to cover the long growth cycle of sugarcane. Furthermore, they do not match the occurrence patterns of pests and diseases, making it difficult to achieve efficient pesticide utilization. At the same time, the synergy between fertilizer and pesticide is insufficient, and they often act independently, making it difficult to achieve synergistic effects. In fact, it may even increase the risk of pesticide damage and reduce fertilizer utilization, failing to meet the needs of modern agriculture for high efficiency, precision, and sustainability. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a multilayer solid carbon source pesticide-fertilizer, its preparation method, and its application. By designing the pesticide and fertilizer to synergize in terms of release sequence and mechanism of action, the release of the pesticide and fertilizer is matched to the specific cycle of sugarcane and the occurrence patterns of pests and diseases, thereby achieving the goals of synergistic effect, risk reduction, and improved utilization.

[0008] To achieve the above objectives, the first aspect of the present invention provides a multilayer solid carbon source fertilizer with a core-shell structure, consisting of an organic fertilizer core layer, a pesticide layer, and a biostimulant layer from the inside out.

[0009] The organic fertilizer core layer contains organic fertilizer, the pesticide layer contains chlorantraniliprole and thiamethoxam, and the biostimulant layer contains humic acid substances.

[0010] The multi-layer solid carbon source fertilizer of this invention consists of a biostimulant layer, a pesticide layer, and an organic fertilizer layer arranged sequentially from the outside to the inside. Through the orderly release of the three layers of fertilizer, the functions of "stimulating the rhizosphere, regulating drug release, and providing long-term nutrition" are achieved, which promotes the efficacy and persistence of the drug, prevents pesticide damage, enhances the sugarcane's absorption capacity and stress resistance, and regulates crop growth and soil health.

[0011] Specifically, after the pesticide-fertilizer mixture is applied to the soil, the outer layer of biostimulants rapidly disintegrates, promoting rapid root growth in sugarcane, improving the rhizosphere microenvironment, and facilitating subsequent absorption of the pesticide by the plant. In the middle pesticide layer, chlorantraniliprole and thiamethoxam are slowly released under the action of polymers, and humic acids also have a solubilizing and adsorption effect on the pesticides, further achieving a smooth and controllable release of the pesticides, effectively reducing the initial risk of phytotoxicity and inhibiting microorganisms, and enhancing the persistence of control. The slow-release process of the innermost organic fertilizer layer can continuously act on the sugarcane throughout its entire growth period, promoting the formation of soil aggregates and the reproduction of beneficial microorganisms, maintaining soil health, and enhancing the crop's resistance to stress.

[0012] In some embodiments, the organic fertilizer core layer also includes a binder; the pesticide layer also includes water-soluble and non-water-soluble polymers, which control and slow release chlorantraniliprole and thiamethoxam through the water-soluble and non-water-soluble polymers.

[0013] In some embodiments, the binder of the organic fertilizer core layer is polyvinyl alcohol, the water-soluble polymer is sodium alginate or sodium carboxymethyl cellulose, and the non-water-soluble polymer is ethyl cellulose or polyvinyl alcohol.

[0014] In some embodiments, the biostimulant layer also includes a water-soluble binder, such as sodium alginate, which causes the biostimulant layer to disintegrate rapidly upon contact with water.

[0015] In some embodiments, the pesticide layer also includes a pore-forming agent, which is sodium chloride (NaCl).

[0016] In some embodiments, the humic acid is fulvic acid or fulvic acid salt, preferably potassium fulvicate, sodium fulvicate, or fulvic acid amine. Due to their small molecular size, high activity, and ability to directly participate in plant metabolism, fulvic acid or fulvic acid salts can promote the growth of sugarcane roots, thereby better promoting the absorption of pesticides by sugarcane and improving its stress resistance.

[0017] In some embodiments, the mass fraction of chlorantraniliprole in the multilayer solid carbon source fertilizer is 0.1-0.5%, and the mass fraction of thiamethoxam is 0.5-1.5%; preferably, the mass fraction of chlorantraniliprole is 0.4%, and the mass fraction of thiamethoxam is 1.2%.

[0018] In some embodiments, the mass ratio of the biostimulant layer, the pesticide layer, and the organic fertilizer core layer is (0.5-2):(1-3):(5-15); preferably 1.5:2.5:12.

[0019] In some embodiments, the organic fertilizer includes at least one of composted livestock and poultry manure, composted crop straw, and composted sugar factory by-products; preferably, composted sugar factory by-products; more preferably, fermented molasses filter mud.

[0020] In some embodiments, the organic fertilizer layer also includes one or more inorganic fertilizers, trace elements, amino acids, seaweed oligosaccharides, and regulators and improvers.

[0021] In some embodiments, in the organic fertilizer core layer, the mass fraction of fermented molasses filter mud is 83-89%, and the mass fraction of polyvinyl alcohol is 1.5-2.5%; in the pesticide layer, the mass fraction of ethyl cellulose is 20-26%, and the mass fraction of sodium alginate is 40-50%; in the biostimulant layer, the mass fraction of humic acid is 90-95%, and the mass fraction of sodium alginate is 5-7%.

[0022] A second aspect of the present invention provides a method for preparing the above-mentioned multilayer solid carbon source fertilizer, comprising the following steps:

[0023] S1. Mix the organic fertilizer with the binder, granulate and dry to obtain organic fertilizer core particles;

[0024] S2. Spray a coating solution containing chlorantraniliprole, thiamethoxam and film-forming materials onto the surface of the organic fertilizer core particles, dry it, then perform cross-linking treatment, and dry it again to form a pesticide layer, thus obtaining two-layer structured particles.

[0025] S3. Alternately spray the binder solution onto the surface of the two-layer structured particles and sprinkle in the dry powder containing humic acid to form a biostimulant layer, thereby obtaining a multi-layer solid carbon source fertilizer.

[0026] In some implementations, in S1,

[0027] Take fermented molasses filter mud, attapulgite soil, zinc sulfate, and borax and mix them evenly;

[0028] The mixture is granulated, and an 8% polyvinyl alcohol aqueous solution is sprayed in simultaneously as a binder during the granulation process to produce wet granules with a particle size of 2.5-3.1 mm.

[0029] The wet granules are dried with hot air until the moisture content of the granules is less than 3.0%; uniform granules with a particle size of 2.5-3.0 mm are sieved out to obtain organic fertilizer core granules for later use.

[0030] In S2,

[0031] The organic fertilizer core particles prepared by S1 are fluidized, the coating liquid is sprayed onto the surface of the core particles, and then a calcium chloride aqueous solution with a mass fraction of 1.5-2.5% is sprayed onto the surface of the fluidized particles for cross-linking treatment. The fluidized drying is continued to obtain two-layer structure particles.

[0032] Preferably, the steps for preparing the coating solution are as follows:

[0033] Ethyl cellulose was dissolved in anhydrous ethanol and stirred until completely transparent to obtain solution A;

[0034] Dissolve sodium alginate in deionized water and stir until completely dissolved to obtain solution B;

[0035] Chlorantraniliprole, thiamethoxam, sodium chloride and alkyl glycosides were added to solution B and stirred until homogeneous to obtain a coarse suspension.

[0036] Solution A was slowly added to the coarse suspension, and shear emulsification was performed to obtain the coating solution;

[0037] More preferably, the mass fraction of the calcium chloride aqueous solution is 2.0%. The crosslinking treatment involves spraying the particles of the coating solution with the calcium chloride aqueous solution.

[0038] In some implementations, in S3,

[0039] Potassium fulvic acid powder and sodium alginate powder are mixed evenly to obtain a mixed dry powder;

[0040] The two-layer structured particles of S2 are placed in a roller coating machine. A 5% sodium alginate aqueous solution is sprayed into the roller coating machine, and then the mixed dry powder is sprinkled in. The spraying and powdering are repeated until the predetermined amount of powder material is evenly coated on the surface of the particles. After drying, multi-layered fertilizer granules are obtained.

[0041] A third aspect of the present invention provides the application of the above-mentioned multilayer solid carbon source fertilizer in sugarcane planting, wherein the effective ingredient dosage of chlorantraniliprole and thiamethoxam is 240-480 g per hectare.

[0042] The beneficial effects of this invention are as follows:

[0043] 1. This invention's fertilizer-pesticide system releases biostimulant, pesticide, and organic fertilizer layers in an orderly manner. The outer layer of biostimulants acts first to rapidly promote root growth and improve the rhizosphere environment, creating favorable conditions for the efficient absorption and translocation of pesticides in the middle layer. The middle layer provides slow-release and precise release of the active ingredients chlorantraniliprole and thiamethoxam, thereby improving pesticide utilization and persistence. Simultaneously, the root-promoting effect of the biostimulants further enhances pesticide utilization and efficiency, and reduces pesticide damage and environmental risks to sugarcane (especially during the seedling stage). Throughout the long growth cycle of sugarcane, this fertilizer-pesticide system continuously provides control over sugarcane borer, reducing the amount of pesticides and fertilizers applied per unit area. It also overcomes the traditional deficiency of disconnected pesticide and fertilizer functions, achieving a synergistic effect of "pesticide-driven fertilizer and fertilizer-enhanced pesticide efficacy." Furthermore, this fertilizer-pesticide system enhances crop resistance and provides nutrients to the crop while improving the soil conditions for crop growth.

[0044] 2. This invention can meet the continuous plant protection and nutrition needs of sugarcane during its key growth period with a single basal application. At the same time, the improved pesticide utilization rate brought about by precise slow release makes it possible to reduce the input of pesticides and fertilizers per unit area under the same prevention effect, thereby reducing the risk of agricultural non-point source pollution from the source. Meanwhile, the number of effective stalks per mu, the weight of a single stalk and the sugar content of sugarcane fields are all greatly improved, resulting in significant comprehensive economic benefits.

[0045] 3. The outer biostimulant layer prepared by this invention has rapid disintegration characteristics, which can quickly release small-molecule active substances such as fulvic acid; the middle pesticide layer, with its non-water-soluble outer membrane and internal three-dimensional network gel structure, can effectively avoid the initial burst release of pesticides and achieve a smooth and sustained release; at the same time, the use of binders in the three-layer structure gives the solid fertilizer good strength and prevents breakage.

[0046] 4. This method utilizes a composite coating solution combined with in-situ crosslinking, obtaining a slow-release pesticide layer through only conventional spraying and a one-step crosslinking treatment. The process route is simple and controllable, suitable for industrial production. Furthermore, the release curve can be adjusted by the concentration of the crosslinking agent, ensuring a high degree of match between pesticide release and the pest's infestation period, thereby reducing the total dosage while maintaining efficacy.

[0047] 5. In the preparation method of this invention, the dry coating process is carried out at low temperature, which effectively avoids the damage of high temperature or solvent to the active ingredients of the middle layer pesticide. At the same time, it also makes each functional layer relatively independent, reducing the risk of adverse chemical reactions caused by direct contact between different components (especially pesticides and fertilizers) during storage, and improving the storage stability of the product. Attached Figure Description

[0048] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0049] Figure 1 This is a schematic diagram of the structure of the multilayer solid carbon source fertilizer of the present invention.

[0050] The layers consist of: 1. Biostimulant layer; 2. Pesticide layer; 3. Organic fertilizer core layer. Detailed Implementation

[0051] To address the problems that existing pesticide-fertilizer products are often simply a combination of pesticides and fertilizers, with pesticides and fertilizers being released simultaneously or pesticides being released before fertilizers, making it difficult to achieve synergistic effects, sudden pesticide release easily causing phytotoxicity to plants, and the release pattern not matching the crop growth cycle and the occurrence pattern of sugarcane borer disease, as well as the easy loss of fertilizers and pesticides with water, this invention proposes a multilayer solid carbon source pesticide-fertilizer, its preparation method, and its application.

[0052] The multi-layered solid carbon source fertilizer obtained above has a three-layer structure, with each layer having a different release rate. Based on the different release rates of active substances or nutrients and their effects on sugarcane, it can be mainly divided into the following three stages:

[0053] The first stage: After the fertilizer and pesticide are applied to the soil, the outermost layer of humic acid or humate dissolves rapidly and acts as a biostimulant to directly stimulate the sugarcane roots, inducing the formation of new lateral roots and root hairs, promoting rapid root growth, and expanding the absorption surface area of ​​the root system. In addition, humic acid also stimulates the reproduction of beneficial microorganisms in the rhizosphere (such as phosphate-solubilizing bacteria and nitrogen-fixing bacteria), enhancing the crop's absorption and stress resistance, so as to promote the efficient absorption of subsequent middle layer pesticides.

[0054] The second stage involves the continuous release of chlorantraniliprole and thiamethoxam from the middle pesticide layer. This ensures that the pesticide's high-efficiency period matches the peak occurrence of key sugarcane pests and diseases (such as the hatching and invasion peak of sugarcane borer larvae), providing sustained control for the crop. Simultaneously, humic acid solubilizes and disperses poorly soluble pesticides (chlorantraniliprole), promoting crop absorption and enhancing its bioavailability. It also adsorbs and releases excess pesticide molecules (such as thiamethoxam), forming a dynamic "pesticide buffer" that slows down the release rate and loss, thereby extending the effective period and reducing the risk of phytotoxicity and loss of active substances in sugarcane due to excessively high initial concentrations. The pesticide's effective period can continuously cover key sugarcane pests and diseases (such as the hatching and invasion peak of sugarcane borer larvae), achieving both reduced and efficient pesticide use and minimizing the risk of phytotoxicity and environmental loss, thus achieving precise and long-lasting control.

[0055] Simultaneously, after the pesticide and fertilizer enter the soil and come into contact with water, the sodium chloride embedded in the membrane dissolves rapidly. The spaces originally occupied by sodium chloride become tiny, interconnected channels. These channels become the main pathways for pesticide molecules (chlorantraniliprole and thiamethoxam) to diffuse from the inside of the membrane into the external soil environment. By adjusting the amount of the pore-forming agent NaCl, the number and density of micropores on the pesticide coating membrane are controlled, thereby regulating the release rate of the pesticide's active ingredients and achieving low initial burst release (<5%) followed by stable release in the middle stage.

[0056] The third stage: The organic fertilizer and various nutrients in the inner layer are slowly decomposed and released under the action of soil microorganisms. At this time, the humic acid applied in the early stage stabilizes the community of beneficial microorganisms and accelerates the humification of organic fertilizer. In the middle and late stages of crop growth, the organic fertilizer and nutrients in the inner layer are continuously and slowly released, stably supplying the basic nutrients, micronutrients and humic acid required by sugarcane throughout its entire growth period. This can continuously improve the soil aggregate structure, enhance water and fertilizer retention capacity, and achieve synergistic growth of crop yield and soil fertility, thereby maintaining soil health from the root.

[0057] Furthermore, the preparation method of this invention forms a sustained-release film with a "dense outer layer - loose inner layer" gradient structure in situ on the particle surface through a single spraying and cross-linking treatment. This two-layer sustained-release structure achieves the effects of preventing initial burst release and ensuring stable release in the middle stage, specifically:

[0058] Initial anti-sudden release: The outermost dense slow-release film of the middle pesticide layer forms the first physical barrier, effectively preventing the instantaneous and large-scale release of pesticides from the interior. This solves the problem of potential sudden release of pesticides and fertilizers in the early stages, greatly reducing the risk of pesticide damage.

[0059] Medium-term stable release: Water in the soil passes through the outer dense slow-release membrane, forming a hydrogel network with the interior. Pesticide molecules must first dissolve in the infiltrated water, and then slowly diffuse through the tortuous channels of the hydrogel network. The swelling properties of the hydrogel and the network pore size determine the diffusion rate.

[0060] This process employs a single spraying and crosslinking step, resulting in a simple preparation method that achieves more stable and sustained release compared to single polymer films. Furthermore, this invention allows for precise control of the release curve by adjusting the ratio of the two film-forming agents, the amount of the pore-forming agent (sodium chloride), and the concentration of the crosslinking agent.

[0061] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments. The following embodiments are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0062] Unless otherwise specified in the embodiments, the conditions are performed according to conventional conditions or the manufacturer's recommendations. All raw materials and equipment used are commercially available products. The main raw materials and equipment used in the embodiments of this invention are as follows:

[0063] raw material:

[0064] Core layer: fermented molasses filter mud (dry basis, crushed through an 80-mesh sieve), attapulgite soil (200-mesh), agricultural zinc sulfate, borax, polyvinyl alcohol (PVA-1788).

[0065] Pesticide layer: Chlorantraniliprole technical (96%), Thiamethoxam technical (95%), Ethyl cellulose (EC, viscosity 10 cps), Sodium alginate (SA, medium viscosity), Sodium chloride, Alkyl glycoside (APG, emulsifier), Anhydrous ethanol.

[0066] Among them, chlorantraniliprole: 3-bromo-N-[4-chloro-2-methyl-6-[(methylcarbamoyl)benzene]-1-(3-chloropyridin-2-yl)-1-hydro-pyrazole-5-carboxamide;

[0067] Thiamethoxam: (E)-1-(2-chloro-1,3-thiazolyl-5-ylmethyl)-3-methyl-2-2-nitroguanidine.

[0068] Biostimulant layer: Potassium fulvic acid powder (fulvic acid ≥50%, K2O ≥10%, passed through a 200-mesh sieve).

[0069] Excipients: Polyvinyl alcohol (PVA-1788), calcium chloride (CaCl2·2H2O).

[0070] Equipment: Three-dimensional motion mixer, extrusion spheronizing granulator, fluidized bed dryer (equipped with bottom spray coating tower), drum coating machine, constant temperature drying oven, high shear dispersion emulsifier.

[0071] Example 1

[0072] The liquid solvents (water, ethanol) added during the process of this embodiment are all evaporated and removed in the corresponding drying process, and are not included in the final product weight.

[0073] This embodiment provides a multilayer solid carbon source fertilizer, and the specific preparation method is as follows:

[0074] Step 1: Preparation of organic fertilizer core granules

[0075] Mixing: Weigh 64.6 kg of fermented molasses filter mud, 7.6 kg of attapulgite clay, 0.8 kg of agricultural zinc sulfate, and 0.4 kg of borax, and put them into a three-dimensional motion mixer and mix them evenly.

[0076] Prepare the adhesive solution: Prepare an 8% (w / w) aqueous solution of polyvinyl alcohol (PVA-1788) for later use.

[0077] Granulation: Transfer the mixed material into an extrusion spheronizing granulator. During the granulation process, simultaneously spray the aforementioned 8% PVA aqueous solution as a binder. The amount sprayed should be based on the appropriate granulation moisture level, where the material can be "kneaded into a ball but crumbles easily when touched" (in this example, approximately 20.0 kg of solution was actually sprayed, equivalent to approximately 1.6 kg of PVA solids). Adjust the extrusion plate and spheronizing speed to prepare wet granules with a particle size of 2.5-3.1 mm.

[0078] Drying and sieving: Immediately transfer the wet granules into a fluidized bed dryer and dry them under hot air conditions at 75±5°C until the moisture content of the granules is less than 3.0%. Use a standard sieve to sieve out uniformly dried granules with a particle size of 2.5-3.0 mm, obtaining approximately 75.0 kg of organic fertilizer core granules for later use.

[0079] Step 2: Constructing the middle layer of controlled-release pesticides

[0080] Preparation of composite coating solution:

[0081] a. Dissolve 3.6 kg of ethyl cellulose in 22.0 kg of anhydrous ethanol and stir until completely transparent to obtain solution A.

[0082] b. Dissolve 7.2 kg of sodium alginate in 54.0 kg of deionized water and stir until completely dissolved to obtain solution B.

[0083] c. Add 0.4 kg of chlorantraniliprole technical (96%), 1.3 kg of thiamethoxam technical (95%), 1.8 kg of sodium chloride and 0.9 kg of alkyl glycoside (APG) to solution B for preliminary dispersion.

[0084] d. Under stirring in a high-speed shear dispersion emulsifier (2000 rpm), slowly add solution A to the mixture from step c, and continue shear emulsification for 5 minutes to form a uniform and stable milky white composite-coated suspension. (The high dosage of ethyl cellulose and sodium alginate aims to construct a sufficiently thick, dense, and deeply cross-linked composite membrane to achieve ultra-strong sustained release and long-term control of high drug loading.)

[0085] Fluidized bed coating and gradient film formation:

[0086] Take all the organic fertilizer core granules prepared in step one and place them in a fluidized bed dryer equipped with a bottom spray coating tower. Preheat the material temperature to 52±2°C and control the inlet air temperature to 60°C.

[0087] The composite coating solution is uniformly sprayed onto the surface of fluidized particles at an appropriate spray rate. During this process, ethanol and water evaporate sequentially, and EC and SA undergo phase separation, spontaneously forming an initial thin film with a gradient structure of EC enrichment (dense outer layer) and SA enrichment (loose inner layer) on the particle surface.

[0088] (Adjust the spray rate to control the particle surface to be moist but not too wet, ensuring that the droplets can dry on the particle surface in time after contacting the particle to form a film, avoiding particle adhesion and forming a uniform and complete gradient film. The spray rate of a single spray gun is usually controlled in the range of 50-150 mL / min).

[0089] In-situ crosslinking and curing: After the coating solution is sprayed, the particles are kept fluidized. A pre-prepared 2.0% (w / w) calcium chloride aqueous solution is sprayed evenly onto the particle surface in a misting manner for crosslinking treatment. The spraying amount is sufficient to ensure that the SA is fully crosslinked (in this example, approximately 23.0 kg of CaCl2 aqueous solution is sprayed).

[0090] Drying: Continue fluidized drying at 50°C for 15 minutes to allow Ca²⁺ to fully penetrate and undergo ionic cross-linking reaction with sodium alginate in the initial film, thus obtaining double-layer coated particles and forming a robust three-dimensional hydrogel network of calcium alginate in situ, thereby completing the construction of the pesticide controlled-release layer.

[0091] Step 3: Construct an outer layer of rapidly disintegrating biostimulant (dry powder coating)

[0092] Preparation: Transfer the coated granules obtained in step two to a drum coating machine. Weigh 8.8 kg of potassium fulvic acid powder and 0.6 kg of sodium alginate powder, and premix them evenly in a container to prepare the outer coating powder.

[0093] Dry coating: Start the roller and set the rotation speed to 20 rpm. Preheat the granules to 40-45°C. Using an alternating operation method, first atomize and spray approximately 0.8 kg of a 5% sodium alginate aqueous solution to form a very thin, adhesive mist; then quickly sprinkle the premixed biostimulant dry powder. Repeat the "spray-powder" cycle until all the outer dry powder material is evenly coated on the granule surface.

[0094] Low-temperature curing: After coating, the granules are placed in a constant temperature drying oven at 40-45°C for static drying for 1 hour to solidify the outer layer, forming a porous, loose outer structure that can quickly disintegrate upon contact with water. This yields a three-layer solid fertilizer, namely chlorantraniliprole·thiamethoxam granules.

[0095] Example 2

[0096] The difference between this embodiment and Example 1 lies in the amount of effective substances added in steps one through three, as follows: In step one, the amount of fermented molasses filter mud added is 68.0 kg; in step two, the amount of chlorantraniliprole technical (96%) added is 0.2 kg, and the amount of thiamethoxam technical (95%) added is 0.6 kg; in step three, the amount of potassium fulvic acid powder added is 8.0 kg. The rest is the same as in Example 1.

[0097] Example 3

[0098] The difference between this embodiment and Embodiment 1 lies in the amount of effective substances added in steps one through three, as follows: In step one, the amount of fermented molasses filter mud added is 59.0 kg; in step two, the amount of chlorantraniliprole technical (96%) added is 0.5 kg and the amount of thiamethoxam technical (95%) added is 1.1 kg; in step three, the amount of potassium fulvic acid powder added is 5.5 kg; the rest is the same as in Embodiment 1.

[0099] Example 4

[0100] The difference between this embodiment and Embodiment 1 is that the mass fraction of the calcium chloride aqueous solution in step two is different; the mass fraction of the calcium chloride aqueous solution is 1.0%, while the rest is the same as in Embodiment 1.

[0101] Example 5

[0102] The difference between this embodiment and Embodiment 1 is that, in step two, sodium alginate is replaced with sodium carboxymethyl cellulose, ethyl cellulose is replaced with polyvinyl alcohol, and the crosslinking agent calcium chloride is replaced with glycolic acid.

[0103] Comparative Example 1

[0104] The difference between this comparative example and Example 1 is that the order of the pesticide layer and the biostimulant layer is different: steps two and three in Example 1 are swapped so that the pesticide layer is the outermost layer and the biostimulant layer is the middle layer.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that the preparation of the composite coating solution in step two is different. The pesticide layer slow-release film in this comparative example has only one layer of ethyl cellulose film. The preparation of the composite coating solution in this comparative example is as follows:

[0107] a. Dissolve 3.6 kg of ethyl cellulose in an appropriate amount of anhydrous ethanol (about 22.0 kg) and stir until completely transparent to obtain solution A.

[0108] b. Add 0.4 kg of chlorantraniliprole technical (96%), 1.3 kg of thiamethoxam technical (95%), 1.8 kg of sodium chloride and 0.9 kg of alkyl glycoside (APG) to solution B for preliminary dispersion.

[0109] c. Under stirring in a high-speed shear dispersion emulsifier (2000 rpm), slowly add solution A to the mixture in step b and continue shear emulsification for 5 minutes to form a uniform and stable milky white composite coated suspension.

[0110] Fluidized bed coating and gradient film formation: This step is the same as in Example 1.

[0111] Drying: Continue fluidized drying at 50°C for 15 minutes to obtain coated granules, thus completing the construction of the pesticide controlled-release layer.

[0112] Comparative Example 3

[0113] The difference between this comparative example and Example 1 is that step three is omitted.

[0114] Comparative Example 4

[0115] The preparation method of the sustained-release granules in this embodiment is as shown in Example 1 of patent CN120167453A.

[0116] This comparative example provides a method for preparing thiamethoxam·chlorantraniliprole sustained-release granules, the preparation method comprising the following steps:

[0117] S1. Preparation of chlorantraniliprole masterbatch: 0.4 Kg chlorantraniliprole, 10 Kg sodium humate, 3 Kg sodium lignosulfonate, 3 Kg styrene powder, 68.1 Kg light calcium carbonate and 0.5 Kg azo dye are mixed and then subjected to air jet milling to form chlorantraniliprole masterbatch with an average particle size of 5 μm.

[0118] S2. Preparation of thiamethoxam mother liquor: Dissolve 1.2 kg of thiamethoxam in 1.44 kg of methyl oleate and then add 0.42 kg of urea-formaldehyde resin to form the first material;

[0119] Then, 2 kg of alkylbenzene sulfonate calcium is mixed with 9.44 kg of water to form a second material, which is then mixed with the first material and sheared to form a third material.

[0120] Finally, 0.5 kg of citric acid solution was mixed evenly with the third material, the pH was adjusted to 5.5, and the temperature was raised to 56℃ and held for 2.7 h. Through heating and solidification, thiamethoxam was encapsulated within the encapsulated material, yielding a controlled-release thiamethoxam microcapsule stock solution.

[0121] S3. Add 15 kg of thiamethoxam mother liquor obtained in step S2 to 85 kg of chlorantraniliprole mother powder obtained in step S1, adsorb and knead, granulate, dry and sieve to obtain thiamethoxam·chlorantraniliprole sustained-release granules.

[0122] Test Example 1

[0123] The fertilizer granules obtained in Examples 1-5 were dark brown spherical granules. Microscopic observation showed that the cross-section of the granules revealed a clear and complete three-layer structure.

[0124] According to GB / T 10516-2012 "Determination of Average Crushing Resistance of Nitrophosphate Fertilizer Granules", the average crushing resistance of the fertilizer and pesticide in Examples 1-5 is greater than 30N, which is significantly better than the general fertilizer standard.

[0125] Test Example 2

[0126] 1. Outer layer disintegration test:

[0127] Take 50g of each of the granules from Example 1, Comparative Example 1, and Comparative Example 2, place them in a constant temperature water bath at 25℃, and observe the disintegration state at regular intervals. After 5 minutes, observe the disintegration of the outer layer of the granules. The results are shown in Table 1.

[0128] 2. Determination of mid-layer pesticide release rate (test method refers to T / CCPIA 099-2021)

[0129] The static water release method was used: 25±1℃, pH 7.0 phosphate buffer, and total displacement method.

[0130] The contents of chlorantraniliprole and thiamethoxam in the buffer solution were determined by high performance liquid chromatography for the intact pesticide and fertilizer granules of Examples 1-5 and Comparative Examples 1, 2, and 4. The cumulative release rate was calculated, and the sustained-release performance and burst-release inhibition ability of the pesticide layer were evaluated. The results are shown in Table 2.

[0131] Table 1. Outer layer disintegration of fertilizer granules

[0132]

[0133] As shown in Table 1, the fertilizer-pesticide granules of Example 1 have a three-layer structure from the inside out: "organic fertilizer core layer - pesticide layer - biostimulant layer". The biostimulant layer rapidly disintegrates and dissolves in water, allowing the biostimulants to preferentially enter the rhizosphere environment, activate root vitality, and improve the rhizosphere microecology, creating favorable conditions for the efficient absorption and translocation of the subsequent middle layer pesticides. In contrast, the layer sequence of Comparative Example 1 is reversed, and the outer layer cannot quickly release biostimulants, thus failing to achieve the synergistic effect of "pesticide-fertilizer and fertilizer-pesticide efficacy".

[0134] Table 2. Cumulative release rates of chlorantraniliprole and thiamethoxam (%)

[0135]

[0136] *In this context, chlorantraniliprole is represented by chlorantraniliprole.

[0137] As shown in Table 2, the cumulative release rates of chlorantraniliprole and thiamethoxam in Examples 1-3 over 24 hours were 3.1-3.5% and 4.3-4.8%, respectively, both ≤5%, which meets the burst release control standards for pesticide slow-release granules. Furthermore, the cumulative release rates of chlorantraniliprole and thiamethoxam in Examples 1-3 increased gradually on days 1, 3, 7, 14, 21, 28, 45, and 60, with no burst release or release stagnation throughout the process. This demonstrates that the present invention has excellent burst release inhibition ability and continuous and stable slow-release characteristics.

[0138] The sustained-release and anti-surge-release effects of Comparative Example 2 (single-layer membrane) and Comparative Example 4 (urea-formaldehyde resin microcapsule encapsulation) were significantly lower than those of Examples 1-3 (the 24-hour release rates of chlorantraniliprole / thiamethoxam in Comparative Example 2 were 15.8% / 18.1%, and the 24-hour release rates of chlorantraniliprole / thiamethoxam in Comparative Example 4 were 15.4% / 19.0%). This demonstrates that the pesticide layer of this invention, employing an EC / SA gradient membrane and in-situ crosslinking for sustained pesticide release, is one of the core technologies for achieving low burst release, long-lasting release, and stable release.

[0139] Although the pesticide layer of Comparative Example 1 is the same EC / SA-Ca gradient crosslinked membrane as that of Example 1, the position of the pesticide layer is different. The 24h release rate of Comparative Example 1 is as high as 18.0% / 22.0%, and the 28d release rate is as high as 92.0% / 95.0%. Its burst release inhibition ability and duration of effect are much lower than those of Example 1. It can be seen that placing the slow-release pesticide layer in the middle layer is a necessary prerequisite for achieving long-term controlled release.

[0140] As can be seen from Examples 1 and 4, the concentration of cross-linking agent has a regulatory effect on the release rate of drugs. When the CaCl2 concentration is reduced from 2.0% to 1.0%, the degree of SA cross-linking decreases, and the release rate of chlorantraniliprole and thiamethoxam is significantly accelerated. The release rate of pesticides can be controlled by adjusting the amount of cross-linking agent.

[0141] Test Example 3: Duration of Control Efficacy and Phytotoxicity Test

[0142] Experiment 1:

[0143] 1. Crops

[0144] 1.1. Experimental site: A sugarcane planting base in Dehong Prefecture, Yunnan Province, with loam soil, pH value of 6.5, organic matter content of 21.57%, and good soil fertility, which meets the experimental requirements.

[0145] 1.2. Experimental crop variety: sugarcane, Yunzhe-08-1609.

[0146] 1.3. Planting conditions: The sugarcane row spacing in the experimental field was 1m. After the previous sugarcane crop was harvested, the soil was loosened and the roots were mounded around the base. Conventional farming practices were followed before and after the sugarcane experiment, and fertilizer and water management conditions were uniform and consistent, indicating a moderate level of management. No other fungicides or pesticides were used during the experiment, and they had no impact on the experimental results.

[0147] 2. Test Methods

[0148] 2.1. Experimental Design

[0149] Table 3 Experimental Treatment Design

[0150]

[0151] 2.2. Application method: Broadcasting method. When hilling up the sugarcane, dig a small trench at the base of the sugarcane, apply the test agent evenly in the trench according to the above test design, and cover it with soil.

[0152] 2.3. Survey time, number of times and methods: During the experiment, the growth of sugarcane in each plot was observed by visual inspection. 29 days after the application of pesticide, when the sugarcane plants in the blank control area showed obvious signs of heart decay, a pest survey was conducted once.

[0153] 2.4. Calculation formula:

[0154] Referring to the "Guidelines for Field Efficacy Trials of Pesticides (II) Part 61: Control of Sugarcane Borer with Insecticides" (GB / T17980.61-2004), the number of dead heart seedlings in each plot and the total number of plants in the plot were counted, and the dead heart rate and control efficacy were calculated.

[0155] The efficacy is calculated according to formulas (1) and (2):

[0156] ......................(1)

[0157] .......(2)

[0158] 3. Results and Analysis

[0159] 3.1. The results of the field efficacy trials are shown in Table 4:

[0160] Table 4. Field efficacy trial results of chlorantraniliprole·thiamethoxam granules (Part 1)

[0161]

[0162] As shown in Table 4, the 1.6% chlorantraniliprole·thiamethoxam granules in Example 1, when applied at active ingredient dosages of 240, 360, and 480 g / ha, showed control efficacy against sugarcane borers 29 days after application of granules of this formulation, which were 77.33%, 85.27%, and 91.38%, respectively, demonstrating high control efficacy. At the same dosage of pesticide active ingredient, the control efficacy was slightly better than that of the granules in Comparative Examples 3 and 4.

[0163] Experiment 2:

[0164] 1. Crops

[0165] 1.1 Experimental site: A sugarcane planting base in Nanning, Guangxi, loam soil, soil pH 6.4, with average fertility.

[0166] 1.2 Experimental Crop Variety: The experimental crop was sugarcane, variety Guitang 44, with plants in the initial tillering stage and growing well. The plot had convenient irrigation and drainage, and the cultivation and management conditions were consistent across all experimental plots.

[0167] 1.3 Planting situation:

[0168] The sugarcane in the experimental field was in the initial hilling stage. Conventional farming practices were followed before and after the experiment, with consistent and uniform fertilizer and water management conditions, indicating a moderate level of management. No other fungicides or pesticides were used during the experiment, and these had no impact on the results.

[0169] 2. Test Methods

[0170] 2.1. Experimental design: Same as Experiment 1.

[0171] 2.2. Application method: When hilling up the sugarcane, mix the test agent with fine soil according to Table 3 and spread it evenly in the furrow next to the sugarcane ridge, and then cover it with soil.

[0172] 2.3. Survey time, number of times and methods: During the experiment, the growth of sugarcane in each plot was observed by visual inspection. At 62 days after the application of pesticide, when the sugarcane plants in the blank control area showed obvious signs of heart decay, a pest survey was conducted. A total of 1 survey was conducted.

[0173] 2.4 Calculation formula: Same as Experiment 1.

[0174] 3. Results and Analysis

[0175] 3.1. The results of the field efficacy trials are shown in Table 5:

[0176] Table 5. Results of field efficacy trials of chlorantraniliprole·thiamethoxam granules (II)

[0177]

[0178] As shown in Table 5, the 1.6% chlorantraniliprole·thiamethoxam granules in Example 1 maintained a high control efficacy against sugarcane borers at 76.82%, 80.29%, and 84.07% respectively 62 days after application, when the effective ingredient dosage was 240, 360, and 480 g / ha. Under the same pesticide effective ingredient dosage, it was significantly superior to the control effects of the granules in Comparative Examples 3 and 4.

[0179] Experiment 3:

[0180] 1. Crops

[0181] 1.1. Experimental site: A sugarcane planting base in Zhanjiang, Guangdong Province, with red soil, soil organic matter of about 2.2%, and pH value of about 5.2.

[0182] 1.2. Experimental crop variety: The experimental crop was sugarcane, and the variety was Sugarcane Yuetang 63237.

[0183] 1.3. Planting situation:

[0184] Sugarcane was planted on August 3rd to provide seed sugarcane for the following year.

[0185] After planting, follow the routine field management plan below:

[0186] Deeply till the soil before land preparation: This will thoroughly break up the topsoil, achieving the standards of deep, loose, fertile, and finely broken soil. After tilling and harrowing, apply sufficient base fertilizer, and deep-ditch 40 kg / mu of high-nitrogen, high-potassium compound fertilizer (15-15-15) (commonly available in the market), mixing it evenly with the soil and avoiding direct contact between the fertilizer and the sugarcane seed.

[0187] Trench planting: Select carefully chosen seedlings for planting, at a rate of 667 m². 2 Plant 1200-1500 seedlings. Place the double-bud sugarcane seedlings flat in the furrow, with the buds facing to both sides, to prevent the top and bottom buds from being exposed, and plant them in a fixed position.

[0188] First hilling: Apply 10 kg / mu of high-nitrogen compound fertilizer as top dressing during the seedling stage to promote rapid seedling growth and enhance tillering ability. During the jointing stage, apply 20 kg / mu of high-nitrogen compound fertilizer in conjunction with the final hilling to enhance lodging resistance, promote rapid stem growth, and increase sugarcane yield.

[0189] 2. Test Methods

[0190] 2.1. Experimental design: Same as Experiment 1.

[0191] 2.2. Application method: When planting in furrows, dig shallow furrows next to the sugarcane ridges, and evenly spread the test agent in the sugarcane furrows according to Table 3, then plant the sugarcane and cover it with soil.

[0192] 2.3. Survey time, number of times and methods: During the experiment, the growth of sugarcane in each plot was observed by visual inspection; 95 days after the application of pesticide, when the sugarcane plants in the blank control area showed obvious signs of heart decay, a pest survey was conducted, and a total of 1 survey was conducted.

[0193] 2.4 Calculation formula: Same as Experiment 1.

[0194] 3. Results and Analysis

[0195] 3.1. The results of the field efficacy trials are shown in Table 6:

[0196] Table 6. Results of field efficacy trials of chlorantraniliprole·thiamethoxam granules (Part III)

[0197]

[0198] As shown in Table 6, the 1.6% chlorantraniliprole·thiamethoxam granules of Example 1 maintained control efficacy of 81.63%, 84.37%, and 86.48% 95 days after application, when the effective ingredient dosage was 240, 360, and 480 g / ha, respectively. Compared with the granules of Comparative Examples 3 and 4, the control effect of the 1.6% chlorantraniliprole·thiamethoxam granules of Example 1 was more significant when the effective ingredient dosage was the same.

[0199] The 1.6% chlorantraniliprole·thiamethoxam granules of Example 1 of this invention maintained a control efficacy of over 76% throughout the entire experimental period (95 days), and had a long duration of effect. Treatments 2, 4, and 5, with an effective ingredient dosage of 360 g / ha, showed that the control efficacy of the fertilizer-pesticide mixture of Example 1 was slightly better than that of Comparative Examples 3 and 4 in the early stage (29 days) of application, but significantly higher in the later stage (95 days). This demonstrates that the fertilizer-pesticide mixture of this invention has superior control efficacy and a longer duration of effect at the same or lower effective ingredient dosage.

[0200] Applying pesticides during the sugarcane seedling stage is more likely to cause phytotoxicity than other growth stages. In Experiment 3, no phytotoxicity occurred when the granules of Example 1 were applied, while slight phytotoxicity occurred when the pesticides and fertilizers of Comparative Examples 3 and 4 were applied. This shows that the slow-release pesticide and fertilizer of the present invention can alleviate phytotoxicity during the most sensitive seedling stage of the crop. The outer biostimulant layer further increases the stress resistance of sugarcane seedlings and provides a further slow-release effect on the pesticide.

[0201] The inventors' investigation revealed that sugarcane fields treated with the carbon-source fertilizer of this invention showed a significant increase in the number of effective stalks per acre, the weight of a single stalk, and the sugar content. Taking Experiment 2 as an example, data from the sugarcane harvest period showed that, at an application rate of 360 grams of active ingredient per hectare for both chlorantraniliprole and thiamethoxam, sugarcane fields treated with the fertilizer of this invention, compared to those treated with the fertilizer of Comparative Example 4, exhibited a 7.5% increase in the number of effective stalks per acre, a 13.8% increase in the weight of a single stalk, and a 1.2% increase in sugar content.

[0202] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multilayer solid carbon source fertilizer with a core-shell structure, characterized in that, From the inside out, the layers are: an organic fertilizer core layer, a pesticide layer, and a biostimulant layer. The organic fertilizer core layer contains organic fertilizer, the pesticide layer contains chlorantraniliprole and thiamethoxam, and the biostimulant layer contains humic acid substances.

2. The multi-layer solid carbon source fertilizer as described in claim 1, characterized in that, The organic fertilizer core layer also includes a binder; the pesticide layer also includes water-soluble and non-water-soluble polymers, which control and slow release chlorantraniliprole and thiamethoxam through water-soluble and non-water-soluble polymers.

3. The multi-layer solid carbon source fertilizer as described in claim 1, characterized in that, The biostimulant layer also includes a water-soluble binder, which is sodium alginate; The pesticide layer also includes a pore-forming agent, which is sodium chloride; Humic acids are fulvic acid and its salt compounds.

4. The multilayer solid carbon source fertilizer as described in claim 1, characterized in that, In the multilayer solid carbon source fertilizer, the mass fraction of chlorantraniliprole is 0.1-0.5%, and the mass fraction of thiamethoxam is 0.5-1.5%. Organic fertilizers include at least one of the following: decomposed livestock and poultry manure, decomposed crop straw, and decomposed sugar factory by-products.

5. The multilayer solid carbon source fertilizer as described in claim 1, characterized in that, The mass ratio of the biostimulant layer, pesticide layer and organic fertilizer core layer is (0.5-2):(1-3):(5-15).

6. The multi-layer solid carbon source fertilizer as described in claim 4, characterized in that, In the core layer of organic fertilizer, the mass fraction of fermented molasses filter mud is 83-89%, and the mass fraction of polyvinyl alcohol is 1.5-2.5%; in the pesticide layer, the mass fraction of ethyl cellulose is 20-26%, and the mass fraction of sodium alginate is 40-50%; in the biostimulant layer, the mass fraction of humic acid is 90-95%, and the mass fraction of sodium alginate is 5-7%.

7. A method for preparing a multilayer solid carbon source fertilizer as described in claim 1, characterized in that, Includes the following steps: S1. Mix the organic fertilizer with the binder, granulate and dry to obtain organic fertilizer core particles; S2. Spray a coating solution containing chlorantraniliprole, thiamethoxam and film-forming materials onto the surface of the organic fertilizer core particles, dry it, then perform cross-linking treatment, and dry it again to form a pesticide layer, thus obtaining two-layer structured particles. S3. Alternately spray the binder solution onto the surface of the two-layer structured particles and sprinkle in the dry powder containing humic acid to form a biostimulant layer, thereby obtaining a multi-layer solid carbon source fertilizer.

8. The method for preparing multilayer solid carbon source fertilizer as described in claim 7, characterized in that, In S2, The organic fertilizer core particles prepared by S1 were fluidized, and the coating solution was sprayed onto the surface of the organic fertilizer core particles. Then, a calcium chloride aqueous solution with a mass fraction of 1.5-2.5% was sprayed onto the surface of the fluidized particles for cross-linking treatment. The fluidized drying was continued to obtain two-layer structure particles. The steps for preparing the coating solution are as follows: Ethyl cellulose was dissolved in anhydrous ethanol and stirred until completely transparent to obtain solution A; Dissolve sodium alginate in deionized water and stir until completely dissolved to obtain solution B; Chlorantraniliprole, thiamethoxam, sodium chloride and alkyl glycosides were added to solution B and stirred until homogeneous to obtain a coarse suspension. Solution A is slowly added to the coarse suspension, and shear emulsification is performed to obtain the coating solution.

9. The method for preparing multilayer solid carbon source fertilizer as described in claim 7, characterized in that, In S1, Take fermented molasses filter mud, attapulgite soil, zinc sulfate, and borax and mix them evenly; The mixture is granulated, and an 8% polyvinyl alcohol aqueous solution is sprayed in simultaneously as a binder during the granulation process to produce wet granules with a particle size of 2.5-3.1 mm. The wet granules are dried with hot air until the moisture content of the granules is less than 3.0%; uniform granules with a particle size of 2.5-3.0 mm are sieved out to obtain organic fertilizer core granules for later use. In S3, Potassium fulvic acid powder and sodium alginate powder are mixed evenly to obtain a mixed dry powder; The two-layer structured particles of S2 are placed in a roller coating machine. A 5% sodium alginate aqueous solution is sprayed into the roller coating machine, and then the mixed dry powder is sprinkled in. The spraying and powdering are repeated until the predetermined amount of powder material is evenly coated on the surface of the particles. After drying, multi-layered fertilizer granules are obtained.

10. The application of a multi-layer solid carbon source fertilizer as described in any one of claims 1-6 in sugarcane cultivation, characterized in that, The effective ingredient dosage for chlorantraniliprole and thiamethoxam is 240-480 g per hectare.

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