Granular pesticide fertilizer for preventing and treating underground pests and preparation method thereof

Abstract

The invention belongs to the technical field of agricultural fertilizers, and particularly relates to a granular pesticide fertilizer for preventing and treating underground pests and a preparation method thereof. The granular pesticide fertilizer is composed of an inner core, a middle layer, a middle layer microcapsule and an outer layer microcapsule. According to the invention, function cooperation is realized through a coaxial multi-layer structure; an inner core is a starch-PVA-sodium alginate porous framework, contains modified zeolite, biochar and a nitrification inhibitor, stabilizes a rhizosphere environment, controls nitrogen release and reserves a diffusion channel; the middle layer is pre-loaded with chlorantraniliprole, is subjected to fluidized bed coating controlled release, and is matched with azadirachtin microcapsules to synergistically prevent insects; the outer-layer low-temperature cross-linked gel micro-capsule protects metarhizium anisopliae, insulates medicaments and resists dust; finally, time sequence synergy is formed, the pesticide effect is guaranteed, leaching loss is low, and crop safety is protected.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of agricultural fertilizer, and particularly relates to a granular pesticide-fertilizer for preventing and treating underground pests and a preparation method thereof. BACKGROUND

[0002] Underground pests, such as grub, wireworm and mole cricket, are common soil-inhabiting pests that harm the growth of various crops. Their damage mainly concentrates on the roots and underground stems of crops, which can lead to a decrease in seedling emergence rate, weak plant growth and yield loss. At present, there are various technical solutions that can be referred to for the control of such pests in agricultural practice. One common control method is the application of chemical pesticides, such as granules of chlorpyrifos, for soil treatment or trenching at the time of sowing. Although this method can provide certain initial control effect, in actual application, the effective ingredient of the pesticide in the soil environment may gradually decrease due to degradation or leaching, which may limit its effectiveness in the middle and late stages of crop growth. In addition, the migration of chemical pesticides in the soil also raises concerns about environmental compatibility. Another technical idea is to physically mix pesticides and fertilizers to form a pesticide-fertilizer composite product, so as to realize the synergy of fertilization and pesticide application. However, in this physical mixing system, the release kinetics curves of the fertilizer carrier and the active ingredient of the pesticide in the soil may be different. For example, the release period of fertilizer nutrients may not completely match the occurrence regularity of pests and the demand persistence period of pesticides, which may challenge the stability of their synergistic effect. In addition, biological control technology, such as the application of entomopathogenic fungi such as Metarhizium, is also considered as a potential control strategy. However, as a living active substance, the survival and colonization efficiency of microbial inoculants is low during processing, storage and after application into the soil, and they are easily affected by environmental factors such as ultraviolet light, temperature, humidity and soil chemical environment. How to maintain the biological activity and control stability after application is still a key problem to be solved in this technical field. SUMMARY

[0003] In view of the defects of the prior art, the purpose of the present application is to provide a granular pesticide-fertilizer for preventing and treating underground pests and a preparation method thereof.

[0004] The technical effect of the present application is realized by the following technical solution: a granular pesticide-fertilizer for preventing and treating underground pests, which is composed of an inner core, a middle layer, a middle layer microcapsule and an outer layer microcapsule. Preferably, the composition of the inner core comprises the following components by weight: 18-22 parts of urea, 10-15 parts of monoammonium phosphate, 6-12 parts of potassium sulfate, 6-10 parts of corn starch, 2-4 parts of polyvinyl alcohol, 1-3 parts of sodium alginate, 0.05-0.1 parts of 3,4-dimethylpyrazole phosphate, 5-7 parts of modified zeolite, 2-4 parts of biochar and 1-3 parts of bentonite. Preferably, the composition of the middle layer includes the following components by weight: 0.65-0.75 parts of chlorantraniliprole, 0.06-0.12 parts of polyoxyethylene laurate, 0.3-0.4 parts of sodium lignosulfonate, 3-5 parts of modified zeolite, and 2-4 parts of biochar; Preferably, the composition of the middle layer microcapsule includes the following components by weight: 0.25-0.35 parts of azadirachtin, 0.5-1 part of gum arabic, 0.5-1 part of β-maltodextrin, and 0.01-0.02 part of vitamin E; Preferably, the composition of the outer layer microcapsule includes the following components by weight: 1-1.5 parts of Metarrhizium spore powder, 0.4-0.6 parts of sodium alginate, 0.4-0.6 parts of sodium lignosulfonate, 0.3-0.5 parts of calcium chloride, 0.2-0.35 parts of trehalose, 0.15-0.25 parts of glycerol, 0.15-0.25 parts of white oil, and 0.5-1 part of talc; Preferably, the activity of the Metarrhizium spore powder is 1×10 9 -1×10 10 CFU / g; Preferably, the preparation of the modified zeolite includes the following steps: A1: mixing zeolite and 0.2-0.5 mol / L HCl solution at a solid-liquid ratio of 1:10, stirring at 45-60°C for 1-2 h, washing to neutral, drying at 105°C for 2-4 h to obtain activated zeolite; A2: mixing the activated zeolite of step A1 and 5-10 wt% aqueous quaternary ammonium salt solution at a solid-liquid ratio of 1:2-4, stirring at 40-55°C for 1 h, filtering, washing with ethanol and deionized water in turn, and drying at 60-80°C to constant weight to obtain modified zeolite; Preferably, the quaternary ammonium salt in step A2 is any one of cetyltrimethylammonium bromide and cetyltrimethylammonium chloride; Preferably, another aspect of the present application provides a preparation method of granular pesticide fertilizer for controlling underground pests, specifically including the following steps: S1: activating the modified zeolite at 120-160°C for 2-4 h, removing moisture, passing through a 300-mesh sieve after cooling, and obtaining pretreated modified zeolite; vacuum degassing the biochar at 50-60°C for 2 h, passing through a 300-mesh sieve, and obtaining pretreated biochar; S2: sequentially adding urea, monoammonium phosphate, potassium sulfate, pretreated modified zeolite of step S1, pretreated biochar of step S1, bentonite, corn starch, polyvinyl alcohol, and 3,4-dimethylpyrazole phosphate, and uniformly mixing at 500 rpm for 8-12 min to obtain a dry-mixed core; S3: spray 2.5wt% sodium alginate solution into the dry mixture of step S2, spray at a rate of 150-200g / min, maintain the material temperature at 38-42℃, stir at 600rpm until the moisture content of the material is 14-16%, extrude and round the particles, spray with 10wt% borax solution, crosslink gently for 60s, dry with hot air at 60-75℃ until the moisture content is 8-10%, cool to room temperature, obtain the slow-release core; S4: add sodium lignosulfonate, polyoxyethylene laurate and chlorantraniliprole into 70wt% isopropanol solution, stir to disperse, then add the remaining pretreated modified zeolite and pretreated biochar of step S1, stir for 60-90min, vacuum filtration, vacuum dry at 45-55℃ for 4h, pass through a 200 mesh sieve, obtain the pesticide load; S5: dissolve gum arabic and beta-maltodextrin in deionized water at 50℃, add vitamin E, dissolve uniformly, obtain the wall material solution; dissolve azadirachtin in 95wt% ethanol solution, then slowly add to the wall material solution, shear at 6000rpm for 6-10min, defoam at low speed for 5min, spray dry, obtain azadirachtin microcapsules; S6: add the pesticide load of step S4, the azadirachtin microcapsules of step S5, and sodium lignosulfonate into deionized water, prepare a 35% solid content spray slurry; take the slow-release core of step S3, place it in a fluidized bed, spray with the spray slurry, then evenly spread the product into bentonite, fluidize at low speed for 3min, obtain spray particles; S7: dissolve sodium alginate in deionized water, then add trehalose and glycerol in sequence, stir at 300rpm for 20min, slowly add Metarhizium anisopliae spore powder, stir gently at 100rpm for 10min, obtain a 28% solid content biocontrol alginate slurry; place the spray particles of step S6 in a fluidized bed, spray with the biocontrol alginate slurry and 5wt% calcium chloride solution; then add talcum powder to the product, sieve, spray with 20wt% white oil diluted with ethanol, dry with hot air at 40℃ for 30min, obtain granular pesticide fertilizer; Preferably, in step S2, the amount of pretreated modified zeolite and pretreated biochar added is respectively corresponding to the respective weight parts in the composition of the core; Preferably, in step S3, the extrusion and rounding parameters are: extrusion orifice plate 1.2-1.4mm, rounding for 90s, obtain 1.5-2mm wet particles; Preferably, in step S3, the amount of borax sprayed is 2%, according to the mass of the wet particles; Preferably, in step S4, the amount of pretreated modified zeolite and pretreated biochar added is respectively corresponding to the respective weight parts in the composition of the middle layer; Preferably, in step S5, the spray drying parameters are: inlet air temperature 160-170℃, outlet air temperature 80-85℃, and feed rate 0.8-1L / h; Preferably, in step S6, the specific parameters of the spray treatment are: material temperature 45-48℃, inlet air temperature 55-58℃, and air flow stable fluidization; atomization gas pressure 0.2MPa, and spray gun distance from material surface 18-22cm; the process is operated in a batch mode, i.e. spraying is stopped and air drying is performed for 5min for solidification after the product mass increases by 1%, and the process is repeated until the spraying liquid is used up; Preferably, in step S7, the specific parameters of the spray treatment are: material temperature 28-30℃, inlet air temperature 35-38℃, atomization gas pressure 0.18MPa, spray gun distance from material surface 20cm, and biocontrol alginate slurry is sprayed for 20-30s first, and then film formation is performed by staggered spraying; i.e. biocontrol alginate slurry is continuously sprayed for 45s, and then calcium chloride aqueous solution is sprayed for 30s, and the cycle is repeated; spraying is stopped and air blowing is performed for 60-90s after 2 cycles are completed; the cycle is repeated until the spraying liquid is used up. Preferably, in step S7, the screening is screening of <0.5mm powder and >3mm large particles.

[0005] The beneficial effects of the present application are as follows: Compared with the prior art, the present application realizes the spatiotemporal ordered cooperation of functional components through the coaxial multi-layer structure of core slow-release-middle layer controlled-release-outer layer protection. The inner core constructs a porous framework with a light cross-linking network of starch-PVA-sodium alginate, and co-fixes nutrients such as urea, monoammonium phosphate, and potassium sulfate; among them, the embedded modified zeolite and biochar buffer the fluctuations of rhizosphere water and pH through reversible adsorption, slow down the instantaneous release of salt, and at the same time, the nitrification inhibitor effectively regulates the transformation of nitrogen forms, reduces the risk of ammonia volatilization and osmotic stress, and provides a stable rhizosphere microenvironment for the colonization of agents and biocontrol bacteria. This inner core structure not only gives the particle strength, but also maintains the connectivity of the internal pores, providing a channel for the diffusion of the outer active ingredients. The middle layer adopts a process combining pre-loading and fluidized bed coating, and pre-loads chlorantraniliprole in the pores of modified zeolite and biochar, and then fixes it on the surface of the inner core by intermittent spraying with sodium lignosulfonate as the binder, forming a controlled-release drug belt based on the "adsorption-diffusion-desorption" mechanism. This design anchors the chemical active ingredients in the surface micropores of the particle, effectively reducing the initial release peak, and making its release behavior consistent with the change of soil humidity. The simultaneously applied azadirachtin microcapsules use their faster diffusion rate to produce feeding inhibition and avoidance, guiding pests into the effective action area of the chemical pesticide, thereby realizing the dual synergy of behavioral intervention and chemical death, and improving the overall control efficiency. The outer layer forms a flexible gel microcapsule layer in situ at the outermost side of the particle through low-temperature staggered spraying of sodium alginate and calcium ions. This process controls the penetration and cross-linking process of calcium ions, avoiding the formation of a dense and hard shell on the surface, ensuring that the gel layer has a continuous pore structure. The green muscadine spores are protected by the gel embedding and the combination of trehalose and glycerol, maintaining high survival activity. In addition, the gel layer effectively blocks the potential inhibition of the middle layer chemical pesticide on the biocontrol spores as a physical barrier, and the white oil film at the end further enhances the anti-dust performance and moisture retention capacity of the product, providing persistent protection for spore survival.

[0006] In summary, the functions between raw materials are precisely spliced by the process sequence and film forming method, the porous structure constructed by the inner core and the stable nitrogen environment provide a permeable and low-stress rhizosphere substrate for the drug effect layer and the biocontrol layer; through the carrier pre-loading and intermittent spraying process, the chemical active ingredients are firmly anchored on the surface of the particle and can be released according to the change of environmental humidity; the microencapsulated plant-derived active ingredients and the chemical layer work together to achieve the efficiency superposition of behavioral interference and chemical death; and the outer gel film maintains the integrity of the pore structure in the middle layer, and completes the spatial isolation and activity protection of the biocontrol components, finally forming a time sequence synergy effect of fast control peak first and long-term maintenance, ensuring the stability of the drug effect, low leaching risk, and the safety of crop growth. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1is a graph of chlorantraniliprole decomposition rate and azadirachtin decomposition rate of granular pesticide fertilizer prepared in Examples 1 to 3 and Comparative Examples 1 to 4 of the present application; Figure 2 is a graph of Metarhizium anisopliae spore survival rate of granular pesticide fertilizer prepared in Examples 1 to 3 and Comparative Examples 1 to 4 of the present application; Figure 3 is a graph of mechanical strength change of granular pesticide fertilizer prepared in Examples 1 to 3 and Comparative Examples 1 to 4 of the present application. DETAILED DESCRIPTION

[0008] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Unless otherwise specified, the raw materials involved in the present application are purchased through the conventional commercial channel. The experimental methods without specific conditions are the conventional methods and conventional conditions well known in the art, or the conditions recommended by the instrument manufacturer.

[0009] Example 1: A granular pesticide fertilizer for preventing and treating underground pests, which is composed of an inner core, a middle layer, a middle layer microcapsule and an outer layer microcapsule; The composition of the inner core includes the following components by weight: 22 parts of urea, 12 parts of monoammonium phosphate, 10 parts of potassium sulfate, 8 parts of corn starch, 2.5 parts of polyvinyl alcohol, 1.5 parts of sodium alginate, 0.08 parts of 3,4-dimethylpyrazole phosphate, 6 parts of modified zeolite, 3 parts of biochar and 2 parts of bentonite; The composition of the middle layer includes the following components by weight: 0.7 parts of chlorantraniliprole, 0.1 parts of polyoxyethylene laurate, 0.35 parts of sodium lignosulfonate, 4 parts of modified zeolite and 3 parts of biochar; The composition of the middle layer microcapsule includes the following components by weight: 0.3 parts of azadirachtin, 0.7 parts of gum arabic, 0.8 parts of β-maltodextrin and 0.02 parts of vitamin E; The composition of the outer layer microcapsule includes the following components by weight: 1.2 parts of Metarhizium anisopliae spore powder, 0.5 parts of sodium alginate, 0.5 parts of sodium lignosulfonate, 0.4 parts of calcium chloride, 0.3 parts of trehalose, 0.2 parts of glycerol, 0.2 parts of white oil and 0.8 parts of talc; The activity of the Metarhizium anisopliae spore powder is 1×10 10 CFU / g; The preparation of the modified zeolite includes the following steps: A1: Mix 10 g of zeolite and 100 mL of 0.4 mol / L HCl solution, stir at 55°C for 1.5 h, wash to neutral, dry at 105°C for 3 h, and obtain activated zeolite; A2: 10 g of the activated zeolite from step A1 was mixed with 30 mL of an 8 wt% aqueous solution of cetyltrimethylammonium bromide, stirred at 50°C for 1 h, filtered, washed sequentially with ethanol and deionized water, and dried at 70°C to constant weight to obtain the modified zeolite; The preparation of the granular pesticide-fertilizer for controlling soil pests specifically comprises the following steps: S1: The modified zeolite was activated by baking at 140°C for 3 h and dehumidified; after cooling, it was passed through a 300-mesh sieve to obtain pretreated modified zeolite; the biochar was vacuum degassed at 55°C for 2 h and then passed through a 300-mesh sieve to obtain pretreated biochar; S2: Urea, monoammonium phosphate, potassium sulfate, pretreated modified zeolite from step S1, pretreated biochar from step S1, bentonite, corn starch, polyvinyl alcohol, and 3,4-dimethylpyrazole phosphate were sequentially added, and mixed at 500 rpm for 10 min to obtain a dry-mixed core; S3: A 2.5 wt% sodium alginate aqueous solution was sprayed into the dry-mixed core from step S2 at a rate of 180 g / min while maintaining the material temperature at 40°C and stirring at 600 rpm until the moisture content of the material was 15%, after which the material was extruded and rounded to form granules, using an extrusion die plate with a hole size of 1.3 mm and a rounding time of 90 s to obtain wet granules with a size of 1.8 mm; the wet granules were lightly crosslinked by spraying a 10 wt% aqueous solution of borax while rolling for 60 s, and then dried with hot air at 70°C until the moisture content was 9%, after which the material was cooled to room temperature to obtain a slow-release core; S4: Sodium lignosulfonate, polyoxyethylene laurate, and chlorantraniliprole were sequentially added to a 70 wt% isopropanol solution and stirred until uniformly dispersed, after which the remaining pretreated modified zeolite and pretreated biochar from step S1 were sequentially added and stirred for 80 min, after which the mixture was vacuum filtered and dried at 50°C for 4 h, and then passed through a 200-mesh sieve to obtain a pesticide load; S5: Gum arabic and β-maltodextrin were dissolved in deionized water at 50°C, after which vitamin E was added and dissolved uniformly to obtain a wall material solution; azadirachtin was dissolved in a 95 wt% ethanol solution, which was then slowly added to the wall material solution, after which the mixture was sheared at 6000 rpm for 8 min and then degassed at low speed for 5 min, after which the mixture was spray dried, with an inlet air temperature of 165°C, an outlet air temperature of 82°C, and a feeding rate of 0.9 L / h to obtain azadirachtin microcapsules; S6: The pesticide load from step S4, the azadirachtin microcapsules from step S5, and sodium lignosulfonate were added to deionized water to prepare a 35% solid content spraying slurry; the slow-release core from step S3 was placed in a fluidized bed and treated with the spraying slurry, with a material temperature of 46°C, an inlet air temperature of 56°C, and a constant air flow rate for fluidization; the atomizing gas pressure was 0.2 MPa, and the spray gun was 20 cm from the material surface; this process was operated intermittently, i.e., spraying was stopped and the material was air-dried for 5 min for solidification after the product mass increased by 1%, and this process was repeated until the spraying slurry was used up; the product was then evenly spread on bentonite and fluidized at low speed for 3 min to obtain a sprayed granule; S7: Dissolve sodium alginate in deionized water, then add trehalose and glycerol in turn, stir at 300 rpm for 20 min, slowly add Metarhizium spore powder, stir at 100 rpm for 10 min, obtain biocontrol alginate slurry with 28% solid content; Put the spraying particles of step S6 into the fluidized bed, use biocontrol alginate slurry and 5wt% calcium chloride aqueous solution for spraying treatment, material temperature 29℃, inlet air temperature 36℃, atomizing gas pressure 0.18MPa, spray gun distance from material surface 20cm, first spray biocontrol alginate slurry for 25s, then staggered spraying film formation; that is, continuously spray biocontrol alginate slurry for 45s, then spray calcium chloride aqueous solution for 30s, cycle alternately; stop spraying and blow air for 80s after completing 2 cycles; repeat the cycle until the spraying liquid is used up; then add talcum powder to the product, screen, screen out <0.5mm powder and >3mm large particles, spray white oil diluted with ethanol to a concentration of 20wt%, 40℃ hot air drying for 30min, obtain granular pesticide fertilizer.

[0010] Example 2: A granular pesticide fertilizer for controlling underground pests, which is composed of an inner core, a middle layer, a middle layer microcapsule and an outer layer microcapsule; The composition of the inner core includes the following components by weight: 20 parts of urea, 15 parts of monoammonium phosphate, 12 parts of potassium sulfate, 10 parts of corn starch, 4 parts of polyvinyl alcohol, 3 parts of sodium alginate, 0.1 parts of 3,4-dimethylpyrazole phosphate, 7 parts of modified zeolite, 4 parts of biochar and 3 parts of bentonite; The composition of the middle layer includes the following components by weight: 0.75 parts of chlorantraniliprole, 0.12 parts of polyoxyethylene laurate, 0.4 parts of sodium lignosulfonate, 5 parts of modified zeolite and 4 parts of biochar; The composition of the middle layer microcapsule includes the following components by weight: 0.35 parts of azadirachtin, 1 part of gum arabic, 1 part of β-maltodextrin and 0.015 parts of vitamin E; The composition of the outer layer microcapsule includes the following components by weight: 1.5 parts of Metarhizium spore powder, 0.6 parts of sodium alginate, 0.6 parts of sodium lignosulfonate, 0.5 parts of calcium chloride, 0.35 parts of trehalose, 0.25 parts of glycerol, 0.25 parts of white oil and 1 part of talcum powder; The activity of the Metarhizium spore powder is 5×10 9 CFU / g; The preparation of the modified zeolite includes the following steps: A1: Mix 10g of zeolite and 100mL of 0.5mol / L HCl solution, stir at 60℃ for 1h, wash to neutral, dry at 105℃ for 4h, obtain activated zeolite; A2: Mix 10g of activated zeolite of step A1 and 20mL of 10wt% cetyltrimethylammonium bromide aqueous solution, stir at 55℃ for 1h, filter, wash with ethanol and deionized water in turn, dry at 80℃ to constant weight, obtain modified zeolite; The preparation of the granular pesticide-fertilizer for preventing and controlling underground pests specifically comprises the following steps: S1: activate the modified zeolite at 160°C for 2h, and remove moisture; sieve the cooled modified zeolite through a 300-mesh sieve to obtain pretreated modified zeolite; vacuum degasify the biochar at 60°C for 2h, and sieve the biochar through a 300-mesh sieve to obtain pretreated biochar; S2: sequentially add urea, monoammonium phosphate, potassium sulfate, the pretreated modified zeolite of step S1, the pretreated biochar of step S1, bentonite, corn starch, polyvinyl alcohol, and 3,4-dimethylpyrazole phosphate into a mixer, and mix them at 500 rpm for 12 min to obtain a dry-mixed core; S3: spray a 2.5 wt% sodium alginate aqueous solution into the dry-mixed core of step S2 at a rate of 200 g / min, maintain the material temperature at 42°C, and stir at 600 rpm until the moisture content of the material is 14%, then extrude and round the material to form particles, use an extrusion die plate with a hole diameter of 1.4 mm, round the particles for 90 s, and obtain 2-mm wet particles; spray a 10 wt% borax aqueous solution on the wet particles, slightly crosslink the particles by rolling for 60 s while spraying, and dry the particles at 75°C until the moisture content is 8%, and then cool the particles to room temperature to obtain a slow-release core; S4: sequentially add sodium lignosulfonate, polyoxyethylene laurate, and chlorantraniliprole into a 70 wt% isopropanol solution, stir and disperse the solution until the components are uniformly dispersed, then sequentially add the remaining pretreated modified zeolite and pretreated biochar of step S1 into the solution, stir the mixture for 90 min, vacuum filter the mixture, and vacuum dry the mixture at 55°C for 4h, and sieve the mixture through a 200-mesh sieve to obtain a pesticide load; S5: dissolve gum arabic and β-maltodextrin in deionized water at 50°C, add vitamin E, and dissolve the components until a wall material solution is obtained; dissolve azadirachtin in a 95 wt% ethanol solution, then slowly add the wall material solution into the azadirachtin solution, shear the mixture at 6000 rpm for 10 min, and remove bubbles from the mixture at a low speed for 5 min, and spray dry the mixture at an inlet air temperature of 170°C, an outlet air temperature of 80°C, and a feeding rate of 1 L / h to obtain azadirachtin microcapsules; S6: add the pesticide load of step S4, the azadirachtin microcapsules of step S5, and sodium lignosulfonate into deionized water to prepare a 35% solid content spraying slurry; place the slow-release core of step S3 in a fluidized bed, and spray the slow-release core with the spraying slurry, maintain the material temperature at 48°C, and maintain the inlet air temperature at 58°C and the air flow rate stable for fluidization; the atomization pressure is 0.2 MPa, and the distance between the spray gun and the material surface is 22 cm; the process is operated in an intermittent mode, i.e., stop spraying and dry the material for 5 min for solidification after the product mass increases by 1% due to spraying, and repeat the process until the spraying slurry is used up; then evenly spread the product into bentonite, and fluidize the product at a low speed for 3 min to obtain sprayed particles; S7: Dissolve sodium alginate in deionized water, then add trehalose and glycerol in turn, stir at 300 rpm for 20 min, slowly add Metarhizium spore powder, stir at 100 rpm for 10 min, obtain biocontrol alginate slurry with 28% solid content; Put the spraying particles of step S6 into the fluidized bed, use biocontrol alginate slurry and 5wt% calcium chloride aqueous solution for spraying treatment, material temperature 30℃, inlet air temperature 38℃, atomizing gas pressure 0.18MPa, spray gun distance from material surface 20cm, first spray biocontrol alginate slurry for 30s, then spray and film alternately; that is, spray biocontrol alginate slurry for 45s, then spray calcium chloride aqueous solution for 30s, cycle alternately; stop spraying and blowing for 90s after completing 2 cycles; repeat the cycle until the spraying liquid is used up; then add talcum powder to the product, screen, screen out <0.5mm powder and >3mm large particles, spray white oil diluted with ethanol to a concentration of 20wt%, 40℃ hot air drying for 30min, obtain granular pesticide fertilizer.

[0011] Example 3: A granular pesticide fertilizer for controlling underground pests, which is composed of an inner core, a middle layer, a middle layer microcapsule and an outer layer microcapsule; The composition of the inner core includes the following components by weight: 18 parts of urea, 10 parts of monoammonium phosphate, 6 parts of potassium sulfate, 6 parts of corn starch, 2 parts of polyvinyl alcohol, 1 part of sodium alginate, 0.05 part of 3,4-dimethylpyrazole phosphate, 5 parts of modified zeolite, 2 parts of biochar and 1 part of bentonite; The composition of the middle layer includes the following components by weight: 0.65 parts of chlorantraniliprole, 0.06 parts of polyoxyethylene laurate, 0.3 parts of sodium lignosulfonate, 3 parts of modified zeolite and 2 parts of biochar; The composition of the middle layer microcapsule includes the following components by weight: 0.25 parts of azadirachtin, 0.5 parts of gum arabic, 0.5 parts of β-maltodextrin and 0.01 parts of vitamin E; The composition of the outer layer microcapsule includes the following components by weight: 1 part of Metarhizium spore powder, 0.4 parts of sodium alginate, 0.4 parts of sodium lignosulfonate, 0.3 parts of calcium chloride, 0.2 parts of trehalose, 0.15 parts of glycerol, 0.15 parts of white oil and 0.5 parts of talcum powder; The activity of the Metarhizium spore powder is 1×10 9 CFU / g; The preparation of the modified zeolite includes the following steps: A1: Mix 10g of zeolite and 100mL of 0.2mol / L HCl solution, stir at 45℃ for 2h, wash to neutral, dry at 105℃ for 2h, obtain activated zeolite; A2: Mix 10g of activated zeolite of step A1 and 40mL of 5wt% cetyltrimethylammonium chloride aqueous solution, stir at 40℃ for 1h, filter, wash with ethanol and deionized water in turn, dry at 60℃ to constant weight, obtain modified zeolite; The preparation of the granular pesticide-fertilizer for preventing and treating underground pests specifically comprises the following steps: S1: activate the modified zeolite at 120℃ for 4h, and remove moisture; sieve the cooled modified zeolite through a 300-mesh sieve to obtain pretreated modified zeolite; vacuum-deaerate the biochar at 50℃ for 2h, and sieve the biochar through a 300-mesh sieve to obtain pretreated biochar; S2: sequentially add urea, monoammonium phosphate, potassium sulfate, the pretreated modified zeolite of step S1, the pretreated biochar of step S1, bentonite, corn starch, polyvinyl alcohol, and 3,4-dimethylpyrazole phosphate into a mixer, and mix them at 500 rpm for 8 min to obtain a dry-mixed core; S3: spray a 2.5wt% sodium alginate aqueous solution into the dry-mixed core of step S2 at a rate of 150 g / min, maintain the material temperature at 38℃, and stir at 600 rpm until the moisture content of the material is 16%, and then perform extrusion and spheronization to obtain 1.5mm wet particles; spray a 10wt% borax aqueous solution to slightly crosslink the wet particles by atomization for 60 s, and then dry the wet particles at 60℃ until the moisture content is 10%, and then cool the wet particles to room temperature to obtain a slow-release core; S4: sequentially add sodium lignosulfonate, polyoxyethylene laurate, and chlorantraniliprole into a 70wt% isopropanol solution, and stir to disperse the ingredients uniformly, and then sequentially add the remaining pretreated modified zeolite and pretreated biochar of step S1, stir for 60 min, vacuum-filter, and vacuum-dry at 45℃ for 4h to obtain a pesticide load; S5: dissolve gum arabic and β-maltodextrin in deionized water at 50℃, add vitamin E, and dissolve the ingredients uniformly to obtain a wall material solution; dissolve azadirachtin in a 95wt% ethanol solution, and then slowly add the wall material solution, shear at 6000 rpm for 6 min, and then deaerate at a low speed for 5 min, and then perform spray drying at an inlet temperature of 160℃ and an outlet temperature of 85℃, and a feeding rate of 0.8 L / h to obtain azadirachtin microcapsules; S6: add the pesticide load of step S4, the azadirachtin microcapsules of step S5, and sodium lignosulfonate into deionized water to prepare a 35% solid-containing spraying slurry; place the slow-release core of step S3 in a fluidized bed, and spray the spraying slurry to treat the slow-release core, maintain the material temperature at 45℃, and stabilize the inlet air temperature at 55℃; the atomization pressure is 0.2 MPa, and the distance between the spray gun and the material surface is 18 cm; the process is operated in an intermittent mode, i.e., after the weight of the product increases by 1%, stop spraying and dry the product with air for 5 min to solidify, and repeat the process until the spraying slurry is used up; and then evenly spread the product into bentonite, and fluidize the product at a low speed for 3 min to obtain sprayed particles; S7: Dissolve sodium alginate in deionized water, then add trehalose and glycerol in sequence, stir at 300 rpm for 20 min, slowly add Metarhizium sp. spore powder, stir at 100 rpm for 10 min, to obtain a biocontrol alginate slurry with a solid content of 28%; place the spray particles of step S6 in a fluidized bed, and use the biocontrol alginate slurry and 5 wt% calcium chloride aqueous solution for spraying treatment, material temperature 28°C, inlet air temperature 35°C, atomizing gas pressure 0.18 MPa, spray gun distance from material surface 20 cm, first spray the biocontrol alginate slurry for 20 s, then spray and form a film in an interleaved manner; that is, continuously spray the biocontrol alginate slurry for 45 s, then spray the calcium chloride aqueous solution for 30 s, and repeat the cycle; after completing 2 cycles, stop spraying and blowing air for 60 s; repeat the cycle until the spraying liquid is used up; then add talcum powder to the product, sieve, sieve out <0.5 mm powder and >3 mm large particles, spray white oil diluted with ethanol to a concentration of 20 wt%, and dry at 40°C with hot air for 30 min to obtain granular pesticide fertilizer.

[0012] Comparative Example 1: The raw materials and operations of Comparative Example 1 and Example 1 are basically the same, the main difference is that in Comparative Example 1, the modified zeolite in the middle layer for loading chlorantraniliprole is completely replaced by unmodified zeolite, and S4 is still performed by the same pre-loading and drying process; the remaining steps and parameters remain the same as in Example 1.

[0013] Comparative Example 2: The raw materials and operations of Comparative Example 2 and Example 1 are basically the same, the main difference is that in Comparative Example 2, the chlorantraniliprole pre-loading of step S4 is cancelled, the pretreated modified zeolite and pretreated biochar originally used in this step are adjusted to be added in step S2, and the total amount remains unchanged, and the dispersion liquid of chlorantraniliprole is directly sprayed onto the surface of the slow-release core with the spraying slurry in S6; the remaining steps and parameters remain the same as in Example 1.

[0014] Comparative Example 3: The raw materials and operations of Comparative Example 3 and Example 1 are basically the same, the main difference is that in Comparative Example 3, azadirachtin is removed, and blank wall material powder with the same solid mass is used to replace it at S5-S6 to maintain the same rheological behavior and weight gain of the spraying slurry; the remaining steps and parameters remain the same as in Example 1.

[0015] Comparative Example 4: The raw materials and operations of Comparative Example 4 and Example 1 are basically the same, the main difference is that in Comparative Example 4, the step S7 cancels the interleaved spraying operation of sodium alginate and calcium chloride, and replaces it with a one-time spraying treatment of first spraying calcium chloride solution and then spraying biocontrol alginate slurry; the remaining steps and parameters remain the same as in Example 1.

[0016] Test Test: Basic situation of the test field: the soil type is brown soil, the soil texture is medium loam, the organic matter content is 14.6 g / kg, the total nitrogen content is 1.58 g / kg, the available phosphorus content is 35.2 mg / kg, the available potassium content is 125.4 mg / kg, and the pH value is 7.5; Test crop: corn variety: Xianyu 335; Planting density: 4500 plants per mu; 180 grains per plot; Test time: from June 2024 to October 2024; Core target: to evaluate the control effect of the product on main underground pests (grubs, wireworms) and seedling stage pests (two-point night moths) in summer corn fields; Test procedure: 7 treatments were set up, randomly arranged in groups, plot area (5m x 5m) 25m 2 , 1m walkway buffer zone was set between plots; Treatment 1: granular pesticide fertilizer prepared by Example 1; Treatment 2: pesticide fertilizer prepared by Comparative Example 1; Treatment 3: pesticide fertilizer prepared by Comparative Example 2; Treatment 4: pesticide fertilizer prepared by Comparative Example 3; Treatment 5: pesticide fertilizer prepared by Comparative Example 4; Treatment 6: conventional fertilization + conventional pesticide (15-15-15 compound fertilizer + chlorpyrifos granules); Treatment 7: blank control (no fertilizer, no pesticide); All treatments were sown once in the ditch, and other field management measures such as tillage, irrigation, weeding and topdressing were consistent (field test arrangement chart as shown in Table 1 below); Table 1. Treatment arrangement of field test

[0017] It should be noted that according to the fertilizer requirement law of corn and the occurrence law of pests, all treatments are equal in nitrogen input; taking 16 kg of N / mu as the basis, the dosage of the product (N accounts for about 14.5%) is 110 kg / mu, that is, treatments 1-5 use this specification; the dosage of the control conventional compound fertilizer (15-15-15) (N accounts for about 15%) is 107 kg / mu, that is, treatment 6 uses this specification; The insect population calculation method is mainly based on the bait method: in each plot, 10 points are set according to the diagonal method, 20 corn kernels soaked overnight with appropriate water and swollen are buried in each point with a depth of 8 cm, and after 48 hours, the number of pests (mainly wireworms and grubs) in them is checked and recorded; the soil drilling method is auxiliary: near the bait point, 0-10 cm and 10-20 cm soil samples are collected respectively by soil drilling, 5 drills per layer, the soil samples in the same layer are mixed, and then the number of underground pests in them is separated and counted by hand picking and wet screening method (this data is used as a supplement to the total base); in each investigation period, the above bait method operation is repeated.

[0018] Measurement index: For emergence and seedling stage, the emergence rate (the percentage of live seedlings in the three-leaf stage after sowing) (%) = (the number of effective emergence plants in the survey area / the number of sown seeds) x 100%; the seedling survival rate (the proportion of healthy seedlings remaining in the five-leaf stage to the number of seedlings in the three-leaf stage, reflecting the damage caused by pests during the seedling stage) (%) = (the number of healthy seedlings in the five-leaf stage / the number of seedlings in the three-leaf stage) x 100%; the root damage rate (%) (the proportion of plants with insect damage spots and notches on the root surface) = (the number of damaged plants / the total number of plants surveyed) x 100% (20 plants / plot); the amount of pests (Heliothis punctigera) per unit area (insects / m 2 ) = total number of live insects / measured area, using the rhizosphere larva investigation method, according to the five-point sampling method, 0.25 m 2 is investigated at each sampling point, the soil around the corn root neck and the covering are dug up, and the number of larvae is directly checked and counted; the results are shown in Table 2 below. Table 2. Summary of corn growth in 7 treatment groups during emergence and seedling stage

[0019] Based on the result analysis of Table 2, the modified carrier preloading and outer gel protection synergistic design are adopted in the embodiment of the application, the chemical lethality and behavior inhibition functions are successfully combined, and a stable in-situ protection zone is constructed in the rhizosphere region, which effectively reduces the initial release peak of the pesticide and ensures the long-term effectiveness, and finally shows the optimal effect in seedling survival rate and root protection. The specific embodiments of the application are described in detail below.

[0020] For the jointing to large trumpet period, the plant height (the vertical height from the ground to the top of the unfolded leaf tip, before the male flowers are extracted, 20 plants are randomly measured per plot, and the average value is taken); the total nitrogen content of the leaf blade (% dry weight), the sample is dried and crushed, the nitrogen is measured by Kjeldahl nitrogen determination, and the result is expressed as % DW; the underground pest (grub and wireworm) density (head / m 2 )=total number of live insects / measured area; the (grub and wireworm) control rate (%)=(total number of pests in the blank control area-total number of pests in the treatment area) / total number of pests in the blank control area*100%; the results are shown in Table 3 as follows; Table 3. Summary of corn growth in the jointing to large trumpet period of 7 treatment groups

[0021] Based on the result analysis of Table 3, under the multiple mechanism of modified carrier preloading + azadirachtin synergism + outer gel protection, the embodiment of the application showed the lowest underground pest density and the highest control rate, and the plant height and leaf total nitrogen content were significantly better than those of other treatments; this shows that the rhizosphere protection belt has excellent in-situ property and persistence, effectively converting pest suppression into crop growth and nutrient accumulation advantage. The pest density and control rate of Comparative Example 1 are inferior to those of Example 1, but are still better than those of the conventional treatment, indicating that carrier modification contributes to improving the control effect by enhancing adsorption and slow-release capacity. The control rate of Comparative Example 2 is significantly reduced, the pest density rises to 2.3 heads / m 2 , the plant height and leaf nitrogen content decrease synchronously, which confirms the key role of the preloading process in maintaining the persistence of the pesticide, and the lack of carrier anchoring leads to insufficient persistence of the pesticide. The control rate and pest density of Comparative Example 3 are between those of Comparative Example 1 and Comparative Example 2, indicating that the lack of plant-derived behavior-modulating components reduces the avoidance and contact efficiency of pests, thereby affecting the overall control effect and crop growth. The indicators of Comparative Example 4 are at a medium level, and the difference between it and Example 1 is mainly due to the decrease in spore protection and release performance caused by the change in the outer cross-linking process. Conventional fertilization + pesticide has a certain pest suppression ability, but its persistence and rhizosphere anchoring ability are obviously insufficient, and the plant height and leaf nitrogen are not outstanding. The blank control as the baseline has the highest pest density, the lowest plant height and leaf nitrogen.

[0022] For the SPAD (relative index of chlorophyll) at the tasseling stage and the SPAD at the grain filling stage, the SPAD value of the ear leaf, and the relative chlorophyll / nitrogen status of the leaf, 3 symmetric points were measured per leaf, and the average value of 20 plants per plot was taken; the green retention rate (%) = (grain filling stage SPAD average value / tasseling stage SPAD average value) x 100%; the results are shown in Table 4 below; Table 4. Summary of corn growth at tasseling to grain filling stage of 7 treatment groups

[0023] Based on the result analysis of Table 4, under the comprehensive action of modified carrier preloading + azadirachtin synergism + outer gel protection, the SPAD values of the embodiment of the application at the male plucking period and the grain filling period are both at a high value, and the green retention rate reaches 92.3%, which are the highest among all treatments, indicating that the senescence delay effect of the functional leaves is optimal, which is beneficial to the sustained accumulation of photosynthetic products at the grain filling period. The SPAD of Comparative Example 1 at the male plucking period is 51.8, and at the grain filling period, it decreases to 46.5, and the green retention rate is 89.8%, which is lower than that of Example 1, indicating that the modification of the carrier helps to maintain the root zone microenvironment and leaf nitrogen assimilation capacity in the middle and late stages. The green retention rate of Comparative Example 2 is only 86.6%, and the SPAD value at the grain filling period decreases to 43.2, reflecting that the control effect of this treatment decreases in the later growth period, which significantly affects the root absorption function and the green retention capacity of the leaves. The green retention rate of Comparative Example 3 is 87.5%, and the SPAD decreases more than that of Comparative Examples 1 and 4, indicating that the lack of the behavior regulation effect of the plant-derived ingredients may cause the increase of the insect population density, thereby affecting the physiological function of the leaves in the middle and late stages. The green retention rate of Comparative Example 4 is 88.2%, and the SPAD change trend is between that of Comparative Examples 1 and 2 / 3, indicating that the outer cross-linking process has a certain influence on the spore activity and the biocontrol effect in the middle and late stages, thereby affecting the sustainability of the leaf function. The SPAD value of the conventional fertilization + pesticide at the grain filling period is 40.5, and the green retention rate is only 83.2%, which is significantly lower than most of the comparative examples, indicating that its effect on maintaining the functional leaves is limited, and the persistence and rhizosphere fixation ability are insufficient. The SPAD value of the blank control decreases significantly from 46.2 at the male plucking period to 36.0 at the grain filling period, and the green retention rate is only 77.9%, reflecting that the leaves are significantly senescent under the stress of insect pests and nutrients.

[0024] For the mature stage, the final yield (kg / mu, converted to 14% moisture) = actual grain weight x (1-actual moisture) / (1-0.14) / actual area; ear grain number (grain / ear) = ear row number x row grain number; 30 ears per plot for average; 100-grain weight (g / 100 grains), randomly selected representative samples, 100 grains were weighed after removing impurities; the results are shown in Table 5 as follows; Table 5. Summary of corn growth at mature stage of 7 treatment groups

[0025] Based on the result analysis of Table 5, under the comprehensive action of modified carrier preloading + azadirachtin synergism + external gel protection, the highest yield is obtained in the embodiment, and the ear number and hundred-grain weight are significantly better than those of other treatments, indicating that the treatment realizes the synchronous improvement of grain quantity and fullness through effective pest control and stable nutrient supply in the whole growth period. The yield, ear number and hundred-grain weight of Comparative Example 1 are slightly lower than those of the embodiment, indicating that the modification of the carrier helps to maintain the stability of the root zone environment in the middle and late periods, and thus plays a positive role in yield formation. The yield of Comparative Example 2 is reduced to 595.1 kg / mu, and the ear number and hundred-grain weight are significantly decreased, reflecting that the treatment has declined in the middle and late periods, which has an adverse effect on the process of grain building and filling. The yield of Comparative Example 3 is 601.8 kg / mu, and the ear number is significantly decreased, indicating that the lack of the behavior regulation function of the plant-derived component may affect the physiological state of the plant in the pollination and grain formation stage. The yield of Comparative Example 4 is 622.3 kg / mu, the ear number is relatively high and the hundred-grain weight is moderate, indicating that the treatment has certain advantages in maintaining the grain quantity, but there is a gap in grain fullness compared with the embodiment. The yield of conventional fertilization + pesticide is 572.6 kg / mu, and the ear number and hundred-grain weight are relatively low, reflecting that the existing conventional measures have limited comprehensive effect in ensuring the yield formation of crops. The yield of the blank control is 510.3 kg / mu, and the ear number and hundred-grain weight are the lowest, reflecting that the yield of crops is significantly inhibited under the dual stress of pests and nutrients.

[0026] Stability test: heat storage test, i.e. the granular pesticide fertilizers prepared in the embodiments 1-3 and comparative examples 1-4 are sealed in ampoule bottles, and stored in a constant temperature oven at 55°C for 14 days; the decomposition rate (%) of chlorantraniliprole and azadirachtin before and after heat storage is detected, i.e. (1-heat storage after effective ingredient content / heat storage before effective ingredient content) x 100%, and the survival rate (%) of metarrhizium spores is (heat storage after spore germination rate / heat storage before spore germination rate) x 100%, HPLC is used to quantitatively determine chlorantraniliprole and azadirachtin; cold storage test, i.e. the granular pesticide fertilizers prepared in the embodiments 1-3 and comparative examples 1-4 are sealed in ampoule bottles, and stored at-12°C for 7 days, and then taken out and placed at room temperature to recover to room temperature, and then measured again to simulate the real temperature cycle, and the mechanical strength change (%) is (cold storage after average compression strength of granules / cold storage before average compression strength of granules) x 100%, and the test results are shown in Figure 1 、 Figure 2 and Figure 3 .

[0027] Based on Figure 1 、 Figure 2 and Figure 3The results analysis shows that the example group of the present application has the lowest chlorantraniliprole decomposition rate and azadirachtin decomposition rate after heat storage, and the Metarhizium spore survival rate and mechanical strength retention rate after cold storage are maintained at a high level, indicating that the modified carrier pre-loading-microencapsulation-outer gel protection system provides effective protection for the chemical active ingredients and biocontrol spores, and endows the granules with excellent physical stability. The stability indicators of Comparative Example 1 are all inferior to those of the example group, indicating that the surface modification of the carrier helps to improve the retention capacity of the active ingredients under thermal stress. The chlorantraniliprole and azadirachtin decomposition rates of Comparative Example 2 are the highest among all treatments, and the spore survival rate is also low, reflecting that the pre-loading process plays a key role in limiting the proportion of free state and inhibiting thermal decomposition. Comparative Example 3 reasonably lacks the azadirachtin component, and the stability performance of the other components is similar to that of Comparative Example 1. The Metarhizium spore survival rate of Comparative Example 4 is significantly lower than that of other treatments, indicating that the uniformity of the outer layer crosslinking is crucial to maintaining the spore survival rate during heat storage; and the mechanical strength retention rate is also the lowest, suggesting that the film forming quality affects the overall structural integrity of the granules.

[0028] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A granular fertilizer for controlling underground pests, characterized in that, It is composed of an inner core, a middle layer, a middle layer microcapsule and an outer layer microcapsule; The composition of the inner core comprises the following components by weight: 18-22 parts of urea, 10-15 parts of monoammonium phosphate, 6-12 parts of potassium sulfate, 6-10 parts of corn starch, 2-4 parts of polyvinyl alcohol, 1-3 parts of sodium alginate, 0.05-0.1 parts of 3,4-dimethylpyrazole phosphate, 5-7 parts of modified zeolite, 2-4 parts of biochar and 1-3 parts of bentonite; The composition of the middle layer comprises the following components by weight: 0.65-0.75 parts of chlorantraniliprole, 0.06-0.12 parts of polyoxyethylene laurate, 0.3-0.4 parts of sodium lignosulfonate, 3-5 parts of modified zeolite and 2-4 parts of biochar; The composition of the middle layer microcapsule comprises the following components by weight: 0.25-0.35 parts of azadirachtin, 0.5-1 parts of gum arabic, 0.5-1 parts of β-maltodextrin and 0.01-0.02 parts of vitamin E; The composition of the outer layer microcapsule comprises the following components by weight: 1-1.5 parts of Metarrhizium spore powder, 0.4-0.6 parts of sodium alginate, 0.4-0.6 parts of sodium lignosulfonate, 0.3-0.5 parts of calcium chloride, 0.2-0.35 parts of trehalose, 0.15-0.25 parts of glycerol, 0.15-0.25 parts of white oil and 0.5-1 parts of talc; The Metarhizium spore powder has an activity of 1 x 10 9 ~ 1 x 10 10 CFU / g.

2. The granular fertilizer for controlling underground pests according to claim 1, characterized in that, The preparation of the modified zeolite comprises the following steps: A1: Mix zeolite and HCl solution, heat and stir, wash to neutral, dry, and obtain activated zeolite; A2: Mix the activated zeolite of step A1 and aqueous quaternary ammonium salt solution, heat and stir, filter, wash with ethanol and deionized water in turn, dry to constant weight, and obtain modified zeolite.

3. The granular fertilizer for controlling underground pests according to claim 2, characterized in that, The quaternary ammonium salt in step A2 is any one of cetyltrimethylammonium bromide and cetyltrimethylammonium chloride.

4. A method of preparing the granular pesticide-fertilizer for controlling soil pests according to any one of claims 1 to 3, characterized by, Specifically comprises the following steps: S1: Activate the modified zeolite and remove moisture; sieve after cooling to obtain pretreated modified zeolite; vacuum degassing the biochar and sieving to obtain pretreated biochar; S2: Add urea, monoammonium phosphate, potassium sulfate, pretreated modified zeolite of step S1, pretreated biochar of step S1, bentonite, corn starch, polyvinyl alcohol and 3,4-dimethylpyrazole phosphate in turn, mix well to obtain dry mixed inner core; S3: Spray sodium alginate solution into the dry mixed inner core of step S2, maintain the material temperature, stir, control the moisture content of the material, extrude and round to form granules, spray with borax aqueous solution, crosslink slightly while spraying, dry with hot air, and cool to room temperature to obtain a slow-release inner core; S4: Add sodium lignosulfonate, polyoxyethylene laurate and chlorantraniliprole into isopropyl alcohol solution in turn, stir and disperse uniformly, then add the remaining pretreated modified zeolite and pretreated biochar of step S1 in turn, stir, vacuum filter, vacuum dry, sieve, and obtain pesticide loading; S5: Dissolve gum arabic and β-maltodextrin in deionized water, add vitamin E, dissolve uniformly to obtain wall material solution; dissolve azadirachtin in ethanol solution, then slowly add it into the wall material solution, shear, low-speed defoaming, spray drying to obtain azadirachtin microcapsule; S6: the pesticide of step S4, the azadirachtin microcapsule of step S5 and sodium lignosulfonate are added into deionized water to prepare a spraying slurry; the slow-release core of step S3 is placed in a fluidized bed and sprayed with the spraying slurry, and then the product is uniformly scattered into bentonite and fluidized at a low speed to obtain sprayed particles; S7: sodium alginate is dissolved in deionized water, then trehalose and glycerol are added in sequence, stirred, and Metarhizium anisopliae spore powder is slowly added and stirred lightly to obtain a biocontrol alginate slurry; the sprayed particles of step S6 are placed in a fluidized bed and sprayed with the biocontrol alginate slurry and a calcium chloride aqueous solution; then talcum powder is added to the product, sieved, sprayed with white oil diluted with ethanol, and hot air dried to obtain granular pesticide fertilizer.

5. A method for preparing a granular pesticide fertilizer for controlling underground pests according to claim 4, characterized in that, In step S3, the extrusion and rolling granulation parameters are as follows: extrusion orifice plate 1.2-1.4 mm, rolling 90 s, and 1.5-2 mm wet particles are obtained.

6. A method of preparing the granular type of pest control granule-fertilizer according to claim 5, characterized by, In step S3, the spraying amount of borax is 2% based on the mass of the wet particles.

7. A method of preparing the granular pesticide-fertilizer for controlling soil pests according to claim 6, characterized by, In step S5, the spray drying parameters are as follows: inlet air temperature 160-170°C, outlet air temperature 80-85°C, and feeding rate 0.8-1 L / h.

8. A method of preparing the granular type of pest control granule-fertilizer according to claim 7, characterized by, In step S6, the specific parameters of the spraying treatment are as follows: material temperature 45-48°C, inlet air temperature 55-58°C, and air flow stable fluidization; atomization gas pressure 0.2 MPa, and spray gun distance from material surface 18-22 cm; the process is operated intermittently, i.e., spraying is stopped and air dried for 5 min for solidification after the product mass increases by 1%, and the process is repeated until the spraying liquid is used up.

9. A method of preparing the granular type of the underground pest control granular pesticide-fertilizer according to claim 8, characterized by, In step S7, the specific parameters of the spraying treatment are as follows: material temperature 28-30°C, inlet air temperature 35-38°C, atomization gas pressure 0.18 MPa, and spray gun distance from material surface 20 cm; short spraying with the biocontrol alginate slurry for 20-30 s is performed first, and then film formation is achieved by staggered spraying; i.e., the biocontrol alginate slurry is continuously sprayed for 45 s, and then the calcium chloride aqueous solution is sprayed for 30 s, and the cycle is repeated; after 2 cycles are completed, spraying is stopped and air is blown for 60-90 s; the cycle is repeated until the spraying liquid is used up.

10. A method of preparing the granule-type pesticide-fertilizer for controlling soil pests according to claim 9, characterized by, In step S7, the sieving is to remove <0.5 mm powder and >3 mm large particles.

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