Barley seed coating agent, preparation method and application thereof

Abstract

The present application belongs to the field of agricultural seed treatment and crop cultivation technology, and particularly relates to a barley seed coating agent and a preparation method and application thereof. The seed coating agent comprises, from inside to outside, an inner core nutrient slow-release layer, an interface bonding layer and an outer pesticide controlled-release layer. The inner core layer is loaded with barley special slow-release nutrients and a modified biochar-attapulgite composite carrier, the interface layer improves the interlayer adhesion, and the outer layer is loaded with pesticide components for preventing and controlling barley seedling stage diseases and pests, thereby realizing rapid prevention and control of seedling stage diseases and pests. The present application realizes time sequence differentiated release of fertilizer and pesticide through a three-layer structure. The outer layer pesticide releases more than 80% within 7 days to rapidly prevent and control diseases and pests, and the inner layer fertilizer steadily releases within 30 days to match the nutrient requirement of barley from the seedling stage to the tillering stage. The interface bonding layer reduces the coating shedding rate to below 3%, thereby significantly improving the storage and field stability. The present application is suitable for the growth characteristics of barley, has the effects of disease resistance, growth promotion and yield increase, has a simple preparation process, and is suitable for large-scale application.

Description

Technical Field

[0001] This invention belongs to the field of agricultural seed treatment and crop cultivation technology, specifically relating to a barley seed coating agent, its preparation method, and its application. Background Technology

[0002] Barley is an important cereal crop in my country, possessing value for food, feed, brewing, and medicine. It plays a vital role in ensuring food security and promoting the development of the livestock and beer industries. Barley is widely cultivated in my country, covering four major producing areas: the Huang-Huai-Hai Plain, the middle and lower reaches of the Yangtze River, Northwest China, and Northeast China. The seedling stage is a crucial foundation for yield formation. During this stage, barley is susceptible to soil-borne diseases such as sheath blight, root rot, and take-all disease, as well as pests such as grubs, wireworms, and aphids. Furthermore, dryland farming areas generally suffer from insufficient nutrient supply during the seedling stage, late tillering, and a low number of effective tillers. These issues, to some extent, restrict the development of large-scale, mechanized barley cultivation and are one of the factors affecting the industry's quality improvement and upgrading.

[0003] Seed coating technology is one of the core technologies for reducing pesticide and fertilizer use while increasing efficiency and promoting simplified crop cultivation. It involves thoroughly mixing pesticides, fertilizers, and other substances with auxiliary materials to form a seed treatment agent with film-forming properties. The outer coating of the seed provides physical protection, preventing damage from pests and diseases. Systemic insecticides exert their effects throughout the plant as it grows, resulting in a long-lasting effect. Seed coating agents have significant effects on pest and disease control, yield increase, and enhanced stress resistance. They are time-saving, pesticide-saving, and have minimal environmental impact, contributing to improved economic, social, and ecological benefits. Seed coating agents mainly consist of two parts: active ingredients and inactive ingredients. The active ingredients are substances that can directly exert their effects, such as insecticides, fungicides, micronutrients, plant growth regulators, and beneficial microorganisms. Inactive ingredients are auxiliary substances that do not act directly but maintain the physicochemical properties of seed coating agents. Their mechanism of action involves the film-forming agent in the seed coating agent tightly binding the active and inactive ingredients together, forming a coating film with capillary, swelling, and slit-like pores on the seed surface. When the seed is sown into the soil, the coating film fully absorbs water, and the active ingredients within slowly degrade or dissolve through the film and pores, forming a protective barrier around the seed and inhibiting soil-borne diseases and underground pests. As the seed germinates and the seedling grows, systemic insecticides or fungicides in the active ingredients, aided by penetrants, are transported from the underground to the above-ground parts of the plant, continuing to control pests and diseases. Micronutrients and hormones such as plant growth regulators also promote plant growth and development.

[0004] Pest and disease control and nutrient supply during the barley seedling stage are core aspects of cultivation management. Seed coating technology allows for precise application of pesticides and fertilizers to the micro-domain surrounding the seed, providing an effective solution to these problems. Existing seed coating products are mostly developed for staple crops such as wheat, corn, and rice, with fewer products specifically designed for barley. Furthermore, these barley seed coating products exhibit some technical shortcomings in practical applications, including: First, barley seeds have a unique morphology and seed coat structure, making existing coatings poorly adaptable. Barley seeds are typically spindle-shaped with a thin seed coat and a high degree of surface keratinization, making it difficult for traditional film-forming systems to adhere evenly. This results in high shedding rates and poor uniformity after coating, reducing both pesticide and fertilizer efficacy and affecting the accuracy of precision mechanical sowing. For example, CN120959247A discloses a pelleted barley seed and its preparation method, comprising 35–40 wt.% talc, 28–32 wt.% bentonite, 8–10 wt.% crospovidone, 15–18 wt.% light calcium carbonate, and 2–5 wt.% perlite. This method uses a specific ratio of talc, bentonite, crospovidone, light calcium carbonate, and perlite to overcome the shortcomings of single-raw materials. The raw materials are combined through a process of "binding, lubrication, reinforcement, filling, and adjustment." The synergistic effect of these methods reduces the phenomena of seed detachment, breakage, clumping, and irregularity during the pelleting process, thereby improving the pelleting rate, enhancing the quality of pelleted barley seeds, strengthening the stress resistance of barley seeds, reducing missed sowing and / or re-sowing of barley seeds, increasing barley yield and quality, and improving barley breeding efficiency. However, its function is limited to physical shaping and simple sterilization and insecticidal effects, lacking bioactive components and stress resistance regulation design. Moreover, the pelleting process is complex and costly, making it unsuitable for large-scale simplified cultivation.

[0005] Secondly, there is a lack of integrated products with single functions and synergistic effects between bacteria and enzymes. Existing products are mostly purely chemical pesticides or single-microbial agents: chemical seed treatments focus on insecticidal and fungicidal action, but long-term, excessive use can easily lead to pathogen resistance, disrupt the soil rhizosphere microecological balance, and lack functions such as promoting growth, providing stress resistance, and supplementing fertilizer. For example, CN114403153B discloses a seed treatment agent containing fluopyram, thiamethoxam, and prothioconazole, with a weight ratio of fluopyram, thiamethoxam, and prothioconazole of 1-20:1-5:1-20. This seed treatment agent can effectively control common diseases of cereal crops, such as barley sheath blight, wilt, leaf spot, rust, sclerotinia rot, clouding, and smut, providing broad disease control but lacking growth-promoting and stress-resistance effects. Microbial seed treatments are environmentally friendly, but the functions of single-inoculum agents are limited, and their growth-promoting effects are unstable under adverse conditions such as low temperature and salinity. CN118480468A discloses a composite coating agent comprising a bacterial composition of simple pure Bacillus sp. and Arthrobacter sp. The composite coating agent includes an adsorbent, a nutrient, a binder, and the bacterial composition. It involves selecting strains with plant growth-promoting effects, compounding them according to certain types and proportions to form a mixed bacterial agent, and combining it with biochar, binder, etc., to form a composite coating agent for coating plant seeds to promote stress-resistant growth. However, it does not consider the characteristics of barley seeds and does not introduce the synergistic effect of enzyme preparations, thus its effect on improving barley germination at low temperatures is limited.

[0006] Third, there is a lack of technology for maintaining microbial activity, resulting in short product shelf life. Directly mixing live bacteria into the coating agent system makes the microorganisms susceptible to rapid inactivation due to factors such as the osmotic pressure of the film-forming agent, the toxicity of chemicals, and storage temperature, leading to short product shelf life and unstable field performance. Current technologies often mitigate this by adding protectants, but lack designs for co-protection and stratified release of both microbial agents and enzymes, making it difficult to fully realize the synergistic effect of microorganisms and enzymes.

[0007] Fourth, there is a lack of systematic control solutions for adverse conditions such as low temperature and salinity. Addressing the challenges of barley spring sowing in low-temperature and saline-alkali soils, existing seed dressing agents mostly rely on single plant growth regulators, resulting in limited effectiveness. The nutrient release rate does not match the nutrient requirements of barley seedlings, easily leading to insufficient nutrient supply in the early stages and waste in the later stages, failing to fully realize the benefits of strong seedlings and increased yield. For example, CN106883019A discloses a seed dressing agent to prevent lodging in barley, including silicon fertilizer, selenium fertilizer, uniconazole, γ-PGA-polyglutamic acid, zinc sulfate, manganese sulfate, ammonium molybdate, borax, EDTA chelated magnesium, calcium cyclamate, schisandra, and codonopsis. These components enhance the mechanical strength and lodging resistance of stems, promote root development and stress resistance. While this can improve stem lodging resistance, it is designed specifically for the growth characteristics of barley. The structure of barley seed coat and the nutrient requirements during the seedling stage differ significantly from those of barley. Direct application results in poor adhesion and a mismatch between the release of active ingredients and the growth stage, limiting overall benefits.

[0008] Meanwhile, existing technologies often involve simply mixing pesticides, fertilizers, and film-forming agents and then coating them onto the seed surface in a single application. In this type of seed coating, pesticides and nutrients are uniformly mixed, and their release is completely synchronized. However, excessively high pesticide concentrations in the early stages can easily cause phytotoxicity to seedlings, and the rapid decrease in concentration later fails to cover the entire seedling stage, which is prone to pests and diseases. Furthermore, nutrient utilization is low. Layered seed coatings, on the other hand, are mostly physically layered structures with weak interfacial bonding, making them prone to delamination and detachment during storage and mechanical sowing, resulting in insufficient reliability of the slow-release function. Commonly used slow-release carriers are polymeric resins, which are difficult to degrade and easily leave soil residues. Natural mineral carriers have low adsorption capacity and poor slow-release effect, and there is a lack of composite carrier materials that combine high slow-release performance with environmental friendliness.

[0009] Therefore, developing a barley-specific seed coating agent that is adapted to the morphology and seed coat characteristics of barley seeds, has the function of layered slow release of pesticides and fertilizers, has storage stability and mechanical tolerance, enables rapid control of pests and diseases by pesticides, provides long-term and time-differentiated release of fertilizers to supply nutrients during the tillering stage, and is environmentally friendly, is of great practical significance for improving the stress resistance and yield stability of barley cultivation and comprehensively improving barley yield and quality. Summary of the Invention

[0010] The purpose of this invention is to overcome the aforementioned problems in the prior art and provide a three-layer sandwich structure barley seed coating agent comprising a core nutrient slow-release layer, an interface bonding layer, and an outer pesticide controlled-release layer. This invention introduces a chemically bonded interface bonding layer into the field of seed coating agents and, combined with a modified biochar-attapulgite composite porous carrier, develops a barley-specific layered slow-release seed coating agent with high stability and high-precision release, effectively solving many defects of the prior art.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: a barley seed coating agent, comprising, from the inside out, a core nutrient slow-release layer, an interface bonding layer, and an outer pesticide controlled-release layer; the core nutrient slow-release layer comprises, by weight, 15-25 parts of slow-release nitrogen source, 10-18 parts of phosphorus and potassium nutrients, 2-5 parts of trace elements, 8-15 parts of modified biochar-attapulgite composite carrier, 3-6 parts of first film-forming agent, 0.5-2 parts of plasticizer, and water to make up to 100 parts; The interface adhesive layer comprises, by weight, 2-5 parts of modified polyvinyl alcohol, 0.3-1 parts of silane coupling agent, and water to make up to 100 parts; The outer pesticide controlled-release layer comprises, by weight, 1-3 parts of fungicide, 0.5-2 parts of insecticide, 4-8 parts of second film-forming agent, 0.5-1.5 parts of dispersant, 0.1-0.3 parts of warning color, and water to make up to 100 parts.

[0012] Furthermore, the slow-release nitrogen source is a mixture of coated urea and urea-formaldehyde at a mass ratio of 2-3:1, which can provide both fast-acting and long-lasting nitrogen supply; the phosphorus and potassium nutrients are a mixture of potassium dihydrogen phosphate and potassium humate at a mass ratio of 1:1-2, and potassium humate can promote root development; the micronutrients are a mixture of chelated zinc, chelated boron, and chelated manganese at a mass ratio of 2:1:1. All micronutrients are in EDTA chelated form, which can avoid precipitation and inactivation problems caused by direct contact with phosphorus, meet the micronutrient requirements of barley seedlings, effectively reduce the risk of tillering deficiency caused by physiological nutrient deficiency, accurately match the micronutrient requirements of barley seedlings, and prevent stunted seedlings due to nutrient deficiency.

[0013] Furthermore, the modified biochar-attapulgite composite carrier is obtained by combining citric acid-modified biochar and attapulgite in a mass ratio of 1:2~3, with a particle size of 200~300 mesh; the first film-forming agent is a mixture of chitosan and sodium carboxymethyl cellulose in a mass ratio of 1:1; attapulgite has a natural one-dimensional nanoporous structure with large adsorption capacity and good water retention; the two are combined to form a multi-level porous structure, which can delay nutrient release through adsorption-desorption and pore diffusion; after being applied to the soil, it can also improve the rhizosphere microenvironment and enhance microbial activity. The specific preparation process of the composite carrier is as follows: Agricultural waste barley straw is heated to 500-600℃ under nitrogen protection at a heating rate of 10℃ / min, and then pyrolyzed at this temperature for 2 hours. After cooling, it is pulverized and passed through a 300-mesh sieve. A 15% citric acid solution is added, and the mixture is placed in a 60℃ water bath for 2 hours for constant temperature modification. After filtration, the filtrate is washed with deionized water until the pH of the filtrate is neutral. After vacuum drying at 60℃, citric acid-modified biochar is obtained. The modified biochar is then thoroughly mixed with natural attapulgite clay at a mass ratio of 1:2-3, and ball-milled at 300 r / min for 30 minutes. The mixture is then passed through a 200-300 mesh sieve to obtain the target composite carrier. The composite carrier prepared under these process conditions can form a dual fixation effect of physical adsorption and chemical fixation of nitrogen, phosphorus, and potassium nutrients, providing support for the stable and slow release of nutrients.

[0014] Furthermore, the plasticizer is a 1:1 mass ratio compound of glycerol and sorbitol, which can effectively improve the flexibility of the core layer after film formation and avoid the problem of film brittleness and peeling during low-temperature drying. The modified polyvinyl alcohol is polyvinyl alcohol 1788 cross-linked with glutaraldehyde. The specific preparation method is as follows: polyvinyl alcohol 1788 particles are added to deionized water at 90°C and stirred until completely dissolved to obtain a 4% (w / w) polyvinyl alcohol solution. After cooling to 55°C, glutaraldehyde is added at 0.2%~0.5% (w / w) of the polyvinyl alcohol mass. A small amount of 1mol / L hydrochloric acid is added dropwise to adjust the pH of the system to 5. After a constant temperature cross-linking reaction for 20 minutes, a small amount of 1mol / L sodium hydroxide solution is added dropwise to neutralize to neutral pH, resulting in a glutaraldehyde cross-linked modified polyvinyl alcohol solution. This modification process can form appropriate cross-linking sites between polyvinyl alcohol molecular chains, ensuring sufficient bonding strength of the interface layer while avoiding excessive film density that hinders the subsequent release of nutrients from the inner layer. The silane coupling agent is KH550. Its amino group at one end can form hydrogen bonds with the hydroxyl groups of polyvinyl alcohol, while its alkoxy group at the other end can chemically bond with the acrylic resin molecules of the outer pesticide controlled-release layer. Simultaneously, the chitosan molecules in the core layer can form intermolecular forces with the modified polyvinyl alcohol in the interface layer, significantly improving the interlayer adhesion of the three-layer structure. This reduces the overall probability of delamination during coating storage, transportation, and mechanical sowing.

[0015] Furthermore, the fungicide is a mixture of fludioxonil and difenoconazole at a mass ratio of 1 to 2:1, which targets and controls soil-borne diseases in the seedling stage such as barley sheath blight, root rot, and take-all disease; the insecticide is thiamethoxam, which has systemic properties and can control underground and above-ground pests such as aphids and grubs, while blocking the spread of viral diseases such as yellow dwarf disease.

[0016] Furthermore, the second film-forming agent is a mixture of acrylic resin emulsion and hydroxypropyl methylcellulose at a mass ratio of 3-4:1. After film formation, it is permeable to water and air, and can regulate the pesticide release rate. The dispersant is sodium lignosulfonate, which improves the suspension stability of pesticide components. The film-forming system forms a uniform pore structure after film formation, enabling rapid dissolution and release of pesticide components upon contact with water in the outer coating, meeting the needs of early-stage pest and disease control in seedlings. The warning color is an acid red water-soluble pigment, which can clearly distinguish between coated and uncoated seeds, avoiding the risk of accidental ingestion.

[0017] The present invention also provides a method for preparing the above-mentioned barley seed coating agent, comprising the following steps: S1. Preparation of core nutrient slow-release layer slurry: The modified biochar-attapulgite composite carrier is mixed and ground with slow-release nitrogen source, phosphorus and potassium nutrients, and trace elements. The first film-forming agent, plasticizer and water are added, and the mixture is sheared and dispersed at 3000~5000r / min for 15~20min to ensure that all components are fully mixed to form a uniform and stable suspension slurry without agglomeration and sedimentation, thus obtaining a uniform core layer slurry. S2. Preparation of interfacial adhesive layer slurry: Add modified polyvinyl alcohol to hot water at 80~90℃ and stir to dissolve. After cooling to below 40℃, add silane coupling agent and continue stirring for 30 minutes until uniform to obtain adhesive layer slurry. S3. Preparation of outer pesticide controlled-release slurry: Mix and grind fungicide, insecticide and dispersant until particle size D90≤5μm, add second film-forming agent, warning color and water, and shear and disperse at 2000~4000r / min for 10~15min to obtain uniform slurry; S4. Step-by-step coating and molding: Barley seeds are placed in a drum coating machine. First, the core nutrient slow-release slurry is sprayed by atomization. After drying with hot air at 40~45℃, the interface bonding slurry is sprayed by atomization. After drying again, the outer pesticide controlled-release slurry is sprayed by atomization. It is then dried with low-temperature hot air at 30~35℃ to avoid the deactivation of active components due to high temperature, while ensuring that the coating film is quickly cured and molded. The broken and sticky particles are removed by sieving to obtain coated barley seeds.

[0018] Furthermore, in step S3, the mixing and grinding is carried out using a sand mill wet grinding method with zirconium oxide beads as the grinding media. The grinding speed is 2000 r / min and the grinding time is 30 min to ensure that the pesticide is uniformly dispersed in the slurry and to avoid excessive local concentration that could cause phytotoxicity.

[0019] Furthermore, in step S4, the coating machine rotates at 30-50 r / min, the core layer drying time is 10-15 min, the interface layer drying time is 5-8 min, and the outer layer drying time is 15-20 min; the total seed-to-coating mass ratio is 1:40-60, that is, every 40-60 kg of barley seeds corresponds to 1 kg of total mass of three-layer coating slurry. This coating ratio can ensure sufficient coating function without causing the overall seed particle size to be too large, which would affect the precision of mechanical sowing.

[0020] The present invention also provides the application of the above-mentioned barley seed coating agent in barley seed coating treatment.

[0021] Furthermore, after coating treatment, the cumulative release rate of pesticides on the outer layer of barley seeds in the soil is ≥80% within 7 days, which can quickly establish a barrier against pests and diseases; the cumulative release rate of nutrients in the kernel is 70%~85% within 30 days, which can stably supply nutrients to barley from the seedling stage to the tillering stage; the coating shedding rate is ≤3% after 6 months of storage at room temperature, and the shedding rate is ≤5% after mechanical sowing abrasion.

[0022] Compared with the prior art, the present invention has the following significant technical advancements: 1. This invention provides a seed coating agent structure with three layers of sequential release, which precisely matches the growth pattern of barley and breaks through the limitations of traditional single-layer or simple double-layer structures. The outer controlled-release pesticide layer releases rapidly after contact with the soil, releasing more than 80% in 7 days, precisely matching the high incidence of pests and diseases 7-15 days after barley sowing; the core nutrient slow-release layer slowly releases nutrients, releasing 70%-85% in 30 days, fully covering the critical nutrient requirement period from barley emergence to tillering, achieving differentiated release of rapid pesticide for disease prevention and long-lasting fertilizer for growth promotion, avoiding nutrient waste in the early stage and nutrient deficiency in the later stage.

[0023] 2. This invention adds an interfacial bonding layer to barley seed coating agents, improving coating stability. A chemically bonded interfacial bonding layer is introduced into the layered seed coating agent. Through the synergistic effect of modified polyvinyl alcohol and silane coupling agents, a stable chemical transition layer is formed between the polysaccharide-based internal film-forming agent and the resin-based external film-forming agent. This solves the problems of weak interlayer physical bonding and easy peeling and detachment in traditional layered seed coating agents. The detachment rate is reduced to below 3% during room temperature storage and below 5% during mechanical sowing abrasion, significantly improving the stability of the slow-release function.

[0024] 3. This invention is a compound pesticide targeting major diseases and pests in barley seedlings. It combines the fertilizer requirements of barley with the formulation of nutrients and micronutrients. At the same time, it introduces a modified biochar-attapulgite composite carrier to improve the rhizosphere microenvironment, resulting in outstanding root-promoting and seedling-strengthening effects. The field control efficacy against barley sheath blight reaches over 90%, which is significantly better than existing ordinary seed dressing agents.

[0025] 4. This invention adopts a stepwise atomization coating process, which does not require complex microcapsule preparation equipment, has a short production process, low energy consumption, no organic solvent residue, is environmentally friendly, and the process is simple and controllable, suitable for large-scale production and easy to scale up industrial production. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein. The reagents used herein may be commercially available related products, and performance testing standards refer to industry or national standards.

[0028] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0029] Example 1 The barley seed coating agent of this embodiment comprises, from the inside out, a core nutrient slow-release layer, an interface bonding layer, and an outer pesticide controlled-release layer. The formulations of each layer are as follows: Core nutrient slow-release layer (by weight): 15 parts slow-release nitrogen source (coated urea: urea-formaldehyde = 2:1), 10 parts phosphorus and potassium nutrients (potassium dihydrogen phosphate: potassium humate = 1:1), 2 parts trace elements (chelated zinc: chelated boron: chelated manganese = 2:1:1), 8 parts modified biochar-attapulgite composite carrier, 3 parts first film-forming agent (chitosan: sodium carboxymethyl cellulose = 1:1), 0.5 parts plasticizer (glycerol: sorbitol = 1:1), deionized water to make up to 100 parts; Interface adhesive layer (by weight): 2 parts modified polyvinyl alcohol (dry weight), 0.3 parts silane coupling agent KH550, and deionized water to make up to 100 parts; Outer pesticide controlled-release layer (by weight): 1 part fungicide (fludioxonil: difenoconazole = 1:1), 0.5 parts insecticide thiamethoxam, 4 parts second film-forming agent (acrylic resin emulsion: hydroxypropyl methylcellulose = 3:1, dry weight), 0.5 parts dispersant sodium lignosulfonate, 0.1 parts warning color Acid Red, and deionized water to make up to 100 parts.

[0030] The preparation method is as follows: S1. Preparation of core nutrient slow-release layer slurry: According to the formula, the composite carrier is mixed and ground with slow-release nitrogen source, phosphorus and potassium nutrients, and trace elements until D90≤10μm. The first film-forming agent, plasticizer and water are added, and the high-speed shearing is performed at 3000r / min for 20min to obtain a uniform suspension slurry. S2. Preparation of interfacial bonding layer slurry: According to the formula, add modified polyvinyl alcohol to 85℃ hot water to dissolve and add water to the concentration. After cooling to 38℃, add KH550 and stir for 30 minutes until uniform. S3. Preparation of outer pesticide controlled-release slurry: According to the formula, fungicide, insecticide and dispersant are mixed with water and ground until D90≤5μm. Add second film-forming agent and warning color, and shear at 3000r / min for 10min to obtain uniform suspension slurry. S4. Step-by-step coating and molding: Barley seeds are placed in a drum coating machine, and the rotation speed is set to 35 r / min. First, the core layer slurry is sprayed by atomization and dried with hot air at 40℃ for 15 min; then the interface layer slurry is sprayed and dried at 32℃ for 8 min; finally, the outer layer slurry is sprayed and dried at 32℃ for 20 min; the total seed-to-medicine mass ratio is 1:40, and after sieving, coated barley seeds are obtained.

[0031] Example 2 The barley seed coating agent of this embodiment comprises, from the inside out, a core nutrient slow-release layer, an interface bonding layer, and an outer pesticide controlled-release layer. The formulations of each layer are as follows: Core nutrient slow-release layer (by weight): 20 parts slow-release nitrogen source (coated urea: urea-formaldehyde = 2.5:1), 14 parts phosphorus and potassium nutrients (potassium dihydrogen phosphate: potassium humate = 1:1.5), 3.5 parts trace elements (chelated zinc: chelated boron: chelated manganese = 2:1:1), 12 parts modified biochar-attapulgite composite carrier, 4.5 parts first film-forming agent (chitosan: sodium carboxymethyl cellulose = 1:1), 1 part plasticizer (glycerol: sorbitol = 1:1), deionized water to make up to 100 parts; Interface adhesive layer (by weight): 3.5 parts modified polyvinyl alcohol (dry weight), 0.6 parts silane coupling agent KH550, and deionized water to make up to 100 parts; Outer pesticide controlled-release layer (by weight): 2 parts fungicide (fludioxonil: difenoconazole = 1.5:1), 1.2 parts insecticide thiamethoxam, 6 parts second film-forming agent (acrylic resin emulsion: hydroxypropyl methylcellulose = 3.5:1, dry weight), 1 part dispersant sodium lignosulfonate, 0.2 parts warning color Acid Red, and deionized water to make up to 100 parts.

[0032] The preparation method is as follows: S1. Preparation of core nutrient slow-release layer slurry: According to the formula, the composite carrier is mixed and ground with slow-release nitrogen source, phosphorus and potassium nutrients, and trace elements until D90≤10μm. The first film-forming agent, plasticizer and water are added, and the high-speed shearing is performed at 4000r / min for 18min to obtain a uniform suspension slurry. S2. Preparation of interfacial bonding layer slurry: Same as in Example 1; S3. Preparation of outer pesticide controlled-release slurry: According to the formula, fungicide, insecticide and dispersant are mixed with water and ground until D90≤5μm. Add second film-forming agent and warning color, and shear at 3500r / min for 12min to obtain uniform suspension slurry. S4. Step-by-step coating and molding: Barley seeds are placed in a drum coating machine, and the rotation speed is set to 40 r / min. First, the core layer slurry is sprayed by atomization and dried with hot air at 42℃ for 12 min; then the interface layer slurry is sprayed and dried at 32℃ for 6 min; finally, the outer layer slurry is sprayed and dried at 32℃ for 18 min; the total seed-to-medicine mass ratio is 1:50, and after sieving, coated barley seeds are obtained.

[0033] Example 3 The barley seed coating agent of this embodiment comprises, from the inside out, a core nutrient slow-release layer, an interface bonding layer, and an outer pesticide controlled-release layer. The formulations of each layer are as follows: Core nutrient slow-release layer (by weight): 25 parts slow-release nitrogen source (coated urea: urea-formaldehyde = 3:1), 18 parts phosphorus and potassium nutrients (potassium dihydrogen phosphate: potassium humate = 1:2), 5 parts trace elements (chelated zinc: chelated boron: chelated manganese = 2:1:1), 15 parts modified biochar-attapulgite composite carrier, 6 parts first film-forming agent (chitosan: sodium carboxymethyl cellulose = 1:1), 2 parts plasticizer (glycerol: sorbitol = 1:1), deionized water to make up to 100 parts; Interface adhesive layer (by weight): 5 parts modified polyvinyl alcohol (dry weight), 1 part silane coupling agent KH550, and deionized water to make up to 100 parts; Outer pesticide controlled-release layer (by weight): 3 parts fungicide (fludioxonil: difenoconazole = 2:1), 2 parts insecticide thiamethoxam, 8 parts second film-forming agent (acrylic resin emulsion: hydroxypropyl methylcellulose = 4:1, dry weight), 1.5 parts dispersant sodium lignosulfonate, 0.3 parts warning color Acid Red, and deionized water to make up to 100 parts.

[0034] The preparation method is as follows: S1. Preparation of core nutrient slow-release layer slurry: According to the formula, the composite carrier is mixed and ground with slow-release nitrogen source, phosphorus and potassium nutrients, and trace elements until D90≤10μm. The first film-forming agent, plasticizer and water are added, and the high-speed shearing is performed at 5000r / min for 15min to obtain a uniform suspension slurry. S2. Preparation of interfacial bonding layer slurry: Same as in Example 1; S3. Preparation of outer pesticide controlled-release slurry: According to the formula, fungicide, insecticide and dispersant are mixed with water and ground until D90≤5μm. Add second film-forming agent and warning color, and shear at 4000r / min for 10min to obtain uniform suspension slurry. S4. Step-by-step coating and molding: Barley seeds are placed in a drum coating machine, and the rotation speed is set to 45 r / min. First, the core layer slurry is sprayed by atomization and dried with hot air at 45℃ for 10 min. Then, the interface layer slurry is sprayed and dried at 35℃ for 5 min. Finally, the outer layer slurry is sprayed and dried at 35℃ for 15 min. The total seed-to-medicine mass ratio is 1:60. After sieving, coated barley seeds are obtained.

[0035] Comparative Example 1 This comparative example uses uncoated naked barley seeds, without any treatment, for baseline comparison.

[0036] Comparative Example 2 This comparative example uses the raw material composition of Example 2. The preparation method is to mix all active ingredients with the outer film-forming system and coat them at once, with a total drug mass ratio of 1:50.

[0037] Comparative Example 3 The barley seed coating agent in this comparative example consists of, from the inside out, a core nutrient slow-release layer and an outer pesticide controlled-release layer. The formulations for each layer are as follows: Core nutrient slow-release layer (by weight): 20 parts slow-release nitrogen source (coated urea: urea-formaldehyde = 2.5:1), 14 parts phosphorus and potassium nutrients (potassium dihydrogen phosphate: potassium humate = 1:1.5), 3.5 parts trace elements (chelated zinc: chelated boron: chelated manganese = 2:1:1), 12 parts modified biochar-attapulgite composite carrier, 4.5 parts first film-forming agent (chitosan: sodium carboxymethyl cellulose = 1:1), 1 part plasticizer (glycerol: sorbitol = 1:1), deionized water to make up to 100 parts; Outer pesticide controlled-release layer (by weight): 2 parts fungicide (fludioxonil: difenoconazole = 1.5:1), 1.2 parts insecticide thiamethoxam, 6 parts second film-forming agent (acrylic resin emulsion: hydroxypropyl methylcellulose = 3:1, dry weight), 1 part dispersant sodium lignosulfonate, 0.2 parts warning color Acid Red, and deionized water to make up to 100 parts.

[0038] The preparation method is as follows: S1. Preparation of core nutrient slow-release layer slurry: According to the formula, the composite carrier is mixed and ground with slow-release nitrogen source, phosphorus and potassium nutrients, and trace elements until D90≤10μm. The first film-forming agent, plasticizer and water are added, and the high-speed shearing is performed at 4000r / min for 18min to obtain a uniform suspension slurry. S2. Preparation of outer pesticide controlled-release slurry: According to the formula, fungicide, insecticide and dispersant are mixed with water and ground until D90≤5μm. Then, the second film-forming agent and warning color are added. The mixture is sheared at 3500r / min for 12min to obtain a uniform suspension slurry. S3. Step-by-step coating and molding: Barley seeds are placed in a drum coating machine, the rotation speed is set to 40 r / min, the inner core layer slurry is first sprayed by atomization, and dried with hot air at 42℃ for 12 min; then the outer layer slurry is sprayed, and dried at 32℃ for 18 min; the total seed-to-medicine mass ratio is 1:50, and after sieving, coated barley seeds are obtained.

[0039] Comparative Example 4 The only difference between this comparative example and Example 2 is that the composite carrier used in this example is the unmodified virgin biochar-attapulgite composite carrier. All other raw materials and preparation methods are identical to those in Example 2. The specific preparation process of this composite carrier is as follows: Agricultural waste barley straw is heated to 500-600°C at a heating rate of 10°C / min under nitrogen protection, and then pyrolyzed at this temperature for 2 hours. After cooling, it is pulverized and passed through a 300-mesh sieve, then placed in a 60°C water bath for 2 hours. After filtration, it is washed with deionized water until the pH of the filtrate is neutral, and then vacuum dried at 60°C to obtain biochar. The biochar and natural attapulgite are thoroughly mixed at a mass ratio of 1:2-3, added to a ball mill, and ball-milled at 300 r / min for 30 minutes. The mixture is then passed through a 200-300 mesh sieve to obtain the composite carrier.

[0040] Comparative Example 5 This comparative example uses commercially available difenoconazole-thiamethoxam suspension seed coating agent specifically for ordinary barley, coated at the recommended dosage.

[0041] The products of each embodiment and comparative example were tested. The coating shedding rate was determined by vibration method according to relevant testing standards, measuring the shedding rate after 6 months of storage at room temperature and the shedding rate after 10 minutes of simulated mechanical sowing and stirring. Release performance was tested using the soil burial method, with constant temperature incubation at 25℃. The cumulative release rate of thiamethoxam was measured on day 7, and the cumulative release rate of available nitrogen was measured on day 30. Indoor germination and seedling growth experiments were conducted using the paper bed germination method, with constant temperature at 20℃. Germination potential was measured on day 4, and germination rate on day 7. Root length and plant height were measured by randomly selecting 20 plants. Field pest and disease control efficacy trials were conducted using the barley variety Supi No. 3 in a large-scale field plot experiment with a plot area of ​​20m². 2The experiment was repeated three times. The disease index of sheath blight was investigated at the three-leaf stage, and the aphid population density was investigated at the early tillering stage to calculate the relative control efficacy. The specific experimental setup was as follows: The field experiment was conducted at the Hohhot Experimental Base of the Inner Mongolia Academy of Science and Technology. The experimental site was irrigated alluvial soil, with a previous crop of corn. Basic soil fertility was: organic matter 18.2 g / kg, available nitrogen 92.5 mg / kg, available phosphorus 23.8 mg / kg, available potassium 186 mg / kg, soil pH 7.8, and irrigation was available. The soil fertility level was considered medium to high in the main barley-producing area. The tested barley variety was Supi No. 3, and the seeding rate was 225 kg / hm². 2 Row spacing 20cm, water twice during the entire growth period, and apply urea at a rate of 150kg / hm². 2 The cultivation and management practices were consistent and conformed to local high-yield cultivation standards. A randomized block design was used, with three replicates per treatment and a plot area of ​​20m². 2 (4m×5m), with 50cm protective rows between each cell. To ensure stable pest and disease population pressure and reproducible experimental results, a combined artificial inoculation and natural occurrence control enhancement model was adopted: for sheath blight, the grain-pathogen culture medium inoculation method was used. Before sowing, the cultured sheath blight pathogen grain preparation was evenly spread in the sowing furrow at an inoculation rate of 10g / m². 2 Aphids were artificially inoculated at the three-leaf stage, with 5 wingless adult aphids per plant, and then caged and kept moist for 24 hours.

[0042] Investigation and Calculation Methods: For sheath blight: Investigations were conducted at the three-leaf stage, with 100 plants randomly selected from each plot. A 0-4 graded standard was used (Grade 0: no lesions; Grade 1: leaf sheath disease, stem unaffected; Grade 2: stem lesion ≤ 1 / 2 circumference; Grade 3: stem lesion > 1 / 2 circumference; Grade 4: plant death). The disease index and relative control efficacy were calculated. Disease index = Σ (number of diseased plants at each level × corresponding level) / (total number of plants surveyed × highest level) × 100 Relative efficacy = (Disease index of blank control - Disease index of treatment) / Disease index of blank control × 100% Aphids: During the early tillering stage, 50 plants were randomly surveyed in each plot. The number of aphids per plant was recorded, and the aphid count per 100 plants was calculated and the relative control efficacy was determined. Relative control efficacy = (Aphid count per 100 plants in the control group - Aphid count per 100 plants in the treatment group) / Aphid count per 100 plants in the control group × 100% Yield: At maturity, 10 plants were sampled from each plot for testing, and the number of effective tillers and the thousand-grain weight were investigated; the middle 3 rows of the actual harvested plot (area 6m²) were tested. 2 ) Threshing and yield calculation, converted to the standard moisture content yield per mu.

[0043] The samples for the coating shedding rate test were coated seeds that had been stored at room temperature in a sealed container for 6 months; the germination test used freshly coated seeds and was conducted according to the standard paper bed method. The seeds were cultured at a constant temperature of 20℃, with 4 replicates per treatment and 50 seeds per replicate. Germination potential was recorded on day 4 and germination rate was recorded on day 7.

[0044] The experimental test results of barley seeds in different treatment groups are shown in Table 1.

[0045] Table 1. Results of barley seed experiments in each example and comparative example.

[0046] As shown in Table 1, the shedding rate of Examples 1-3 after 6 months of storage at room temperature was below 3%, and the shedding rate due to mechanical wear was below 5%. In Example 2, the shedding rate at room temperature was only 2.1%, and the shedding rate due to mechanical wear was only 3.6%, significantly higher than the 7.9% and 12.6% of Comparative Example 3. This demonstrates that the interfacial bonding of the layered seed coating agent is weak, making it prone to delamination during storage and mechanical sowing. In Comparative Example 3, after removing the interfacial bonding layer, the layers are only bound by physical adsorption and intermolecular forces, making them highly susceptible to delamination under vibration and friction, with a shedding rate 3-4 times higher than that of the Examples. Therefore, the chemically bonded interfacial layer introduced in this invention, through hydrogen bonding between modified polyvinyl alcohol and the core polysaccharide film-forming agent, and covalent bonding between the silane coupling agent and the outer resin, constructs a stable chemical transition interface between the inner and outer layers, solving the problem of delamination. The drop rates of Comparative Example 4 and Example 2 are similar, indicating that carrier modification does not affect coating adhesion. The drop rate of Comparative Example 2 is higher than that of Example 2 but lower than that of Comparative Example 3, further confirming that the interface layer is a key factor in improving the stability of the layered structure. The drop rate of the commercially available product Comparative Example 5 after 6 months of storage at room temperature was 6.5%, and the mechanical wear drop rate was 10.2%, which also reflects the significant improvement of the present invention in coating stability compared with existing products. It should be noted that the drop rate test in this experiment was conducted on aged samples stored for 6 months, while the germination test used freshly coated seeds. At this time, the interlayer adhesion has not deteriorated due to storage, and the coating film is highly intact. Therefore, the germination rate of fresh seeds in Comparative Example 3 is not significantly different from that in Example 2, only reflecting the germination safety of the coating formula, and there is no direct correlation with the drop rate after storage. The loss of effective ingredients caused by drop after storage is ultimately reflected in the decrease in field efficacy and yield. The efficacy and yield per acre of Comparative Example 3 are significantly lower than those of Example 2, directly confirming the role of the interface adhesion layer in ensuring actual field efficacy.

[0047] In Table 1, the cumulative release rates of the outer layer pesticides over 7 days in the three examples were 82.3%, 87.5%, and 90.8%, respectively; the cumulative release rates of the kernel nutrients over 30 days were 72.6%, 78.4%, and 83.2%, respectively. These release patterns closely match the fertilizer and pesticide requirements of barley during its growth period, effectively addressing the problem of "simultaneous pesticide and nutrient release, leading to pesticide damage from excessively high pesticide concentrations in the early stages and nutrient deficiency in the later stages." In contrast, Comparative Example 2 showed a pesticide release rate of only 68.4% over 7 days, failing to quickly establish a protective barrier before the peak period of pests and diseases; while its nutrient release rate over 30 days was as high as 91.5%, indicating that nutrient release was concentrated in the early stages but insufficient in the later stages, failing to cover the peak fertilizer demand during the tillering stage. The nutrient release rate of Comparative Example 4 reached 92.7% after 30 days, close to that of Comparative Example 2 and far higher than the 78.4% of Example 2. This directly demonstrates the key role of the citric acid-modified biochar-attapulgite composite carrier in the slow release of nutrients. Specifically, the modified carrier surface has increased oxygen-containing functional groups, enhancing its adsorption and fixation capacity for nitrogen, phosphorus, and potassium ions. Combined with the diffusion-blocking effect of the multi-level pores, this extends the nutrient release cycle to over 30 days, achieving a stable supply. Comparative Example 3 showed no significant difference in release patterns compared to Example 2, indicating that although the interface layer improved adhesion, it did not form a dense barrier layer to hinder substance transport.

[0048] As can be seen from the experimental data related to seed germination and seedling growth in Table 1, the germination potential, germination rate, root length, and plant height of the groups in this invention are significantly better than those of the blank control and commercially available seed coating agents. Example 2 showed a germination potential of 92.6% and a germination rate of 96.9%, with an average root length of 8.8 cm and a plant height of 14.3 cm, significantly improved compared to the blank control. This demonstrates the outstanding root-promoting and seedling-strengthening effect of the present invention. It further verifies that the three-layer structure design concentrates the pesticide in the outer layer, preventing direct contact with the seed embryo, thus avoiding the germination inhibition that might occur in the single-layer coating of Comparative Example 2, where the germination rate was only 90.8%, lower than the 96.9% of Example 2, indirectly confirming that the layered structure can reduce the risk of pesticide damage.

[0049] Meanwhile, the slow-release nutrients in the core layer continuously supply seedling root growth, and the synergistic effect of potassium humate and chelated trace elements significantly promotes root development. The root length in this example is significantly longer than in Comparative Example 5, indicating that this invention not only controls pests and diseases but also enhances seedling growth through precise nutrient supply, laying the foundation for later tillering and panicle formation. The germination indices of Comparative Examples 3 and 4 show little difference from Example 2, further demonstrating that the modification of the interface layer and carrier mainly affects coating stability and the nutrient slow-release period, without negatively impacting seed water absorption and germination.

[0050] As shown in Table 1, the field pest and disease control data of this invention demonstrate that the control efficacy against barley seedling sheath blight reached 84.7%–91.2%, and against aphids reached 82.4%–90.1%, both significantly better than Comparative Examples 2 and 5. This verifies the technical effectiveness of the invention's rapid release of the outer layer pesticide and precise matching with the peak period of pests and diseases. The outer layer pesticide release rate of the example group exceeded 80% within 7 days, forming a high-concentration protective circle around the seeds before the peak window period of pests and diseases after sowing. In contrast, the single-layer coated pesticide in Comparative Example 2 released slowly, with a release rate of less than 70% within 7 days, failing to establish a protective barrier in time, resulting in lower control efficacy. From a formulation perspective, the combination of fludioxonil and difenoconazole, with their different mechanisms of action, can synergistically control multiple soil-borne diseases such as sheath blight and root rot, delaying the development of resistance. Thiamethoxam has strong systemic conductivity, simultaneously controlling underground grubs and above-ground aphids, and blocking the spread of yellow dwarf virus, achieving multiple preventions with one pesticide. In addition, the control effect of Comparative Example 3 was slightly lower than that of Example 2, possibly because the absence of an interface layer led to coating peeling and some pesticide loss.

[0051] Yield and agronomic traits of the products of each embodiment and comparative example were tested, and the corresponding experimental test results are shown in Table 2. Specifically, the yield and agronomic traits test involved taking 10 plants from each plot at maturity to measure the number of effective tillers and the weight of 1,000 grains, and converting the actual yield into the yield per mu.

[0052] Table 2. Results of barley seed yield and agronomic traits in each example and comparative example.

[0053] Table 2 shows that the yield per mu (a Chinese unit of area, approximately 0.067 hectares) of all three examples was significantly higher than that of the control. Example 2 yielded 432.5 kg / mu, an increase of 20.6%. Example 3 had the highest yield of 445.8 kg / mu. This increase mainly came from the increased number of effective tillers and the improved thousand-grain weight. Example 2 had 5.7 effective tillers per plant, far exceeding Comparative Example 1, and its thousand-grain weight was 43.8 g, also showing an improvement over Comparative Example 1. Furthermore, the increased yield was attributed to effective pest and disease control and a stable nutrient supply during the tillering stage. Comparative Examples 2 and 4, due to mismatched nutrient release, had fewer effective tillers and lower thousand-grain weights, further validating the synergistic effect of the present invention.

[0054] The test results from the above embodiments and comparative experiments show that the outer layer of pesticide in this invention rapidly establishes a protective barrier, reducing damage to seedlings from pests and diseases during the seedling stage and ensuring uniform emergence and a sufficient number of seedlings. The core nutrients are released steadily over 30 days, precisely covering the peak nutrient demand during the tillering stage, promoting effective tillering. The interface layer reduces the shedding rate, ensuring the actual efficacy of the pesticide and fertilizer in the field. The synergistic effect of each functional layer collectively solves the problems existing in barley seeds.

[0055] The preferred embodiments of the present invention have been described in detail above, and are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A barley seed coating agent, characterized in that, From the inside out, it includes a core nutrient slow-release layer, an interface bonding layer, and an outer pesticide controlled-release layer; the core nutrient slow-release layer includes, by weight, 15-25 parts slow-release nitrogen source, 10-18 parts phosphorus and potassium nutrients, 2-5 parts trace elements, 8-15 parts modified biochar-attapulgite composite carrier, 3-6 parts first film-forming agent, 0.5-2 parts plasticizer, and water to make up to 100 parts; The interface adhesive layer comprises, by weight, 2-5 parts of modified polyvinyl alcohol, 0.3-1 parts of silane coupling agent, and water to make up to 100 parts; The outer pesticide controlled-release layer comprises, by weight, 1-3 parts of fungicide, 0.5-2 parts of insecticide, 4-8 parts of second film-forming agent, 0.5-1.5 parts of dispersant, 0.1-0.3 parts of warning color, and water to make up to 100 parts.

2. The barley seed coating agent according to claim 1, characterized in that, The slow-release nitrogen source is a mixture of coated urea and urea-formaldehyde at a mass ratio of 2-3:1; the phosphorus and potassium nutrients are a mixture of potassium dihydrogen phosphate and potassium humate at a mass ratio of 1:1-2; and the trace elements are a mixture of chelated zinc, chelated boron, and chelated manganese at a mass ratio of 2:1:

1.

3. The barley seed coating agent according to claim 1, characterized in that, The modified biochar-attapulgite composite carrier is obtained by combining citric acid-modified biochar and attapulgite in a mass ratio of 1:2~3, with a particle size of 200~300 mesh; the first film-forming agent is a mixture of chitosan and sodium carboxymethyl cellulose in a mass ratio of 1:

1.

4. The barley seed coating agent according to claim 1, characterized in that, The modified polyvinyl alcohol is polyvinyl alcohol 1788 crosslinked with glutaraldehyde; the silane coupling agent is KH550.

5. The barley seed coating agent according to claim 1, characterized in that, The fungicide is a mixture of fludioxonil and difenoconazole at a mass ratio of 1 to 2:1; the insecticide is thiamethoxam.

6. The barley seed coating agent according to claim 1, characterized in that, The second film-forming agent is an acrylic resin emulsion and hydroxypropyl methylcellulose mixed at a mass ratio of 3-4:1; the dispersant is sodium lignosulfonate.

7. A method for preparing the barley seed coating agent according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Preparation of core nutrient slow-release layer slurry: The modified biochar-attapulgite composite carrier is mixed and ground with slow-release nitrogen source, phosphorus and potassium nutrients, and trace elements. The first film-forming agent, plasticizer and water are added and dispersed by high-speed shearing to obtain a uniform slurry. S2. Preparation of interfacial adhesive layer slurry: Dissolve modified polyvinyl alcohol in hot water, cool it down, add silane coupling agent and stir evenly to obtain adhesive layer slurry; S3. Preparation of outer pesticide controlled-release slurry: Mix and grind fungicide, insecticide and dispersant, add second film-forming agent, warning color and water, and shear and disperse to obtain uniform slurry; S4. Step-by-step coating and molding: Place barley seeds in a coating machine, first spray the kernel nutrient slow-release slurry, then spray the interface bonding slurry after hot air drying, then spray the outer pesticide controlled-release slurry after drying again, and dry with hot air at 30~35℃ to obtain coated barley seeds.

8. The method according to claim 7, characterized in that, In step S4, the coating machine speed is 30~50 r / min, the core layer spraying temperature is 40~45℃, and the drying time is 10~15 min; the interface layer and outer layer spraying temperatures are 30~35℃, and the drying times are 5~8 min and 15~20 min, respectively. The total drug quality ratio is 1:40~60.

9. The use of the barley seed coating agent according to any one of claims 1 to 6 in barley seed coating treatment.

10. The application according to claim 9, characterized in that, After coating treatment, barley seeds in the soil have a cumulative release rate of pesticides from the outer layer of ≥80% after 7 days and a cumulative release rate of nutrients from the kernel of 70%~85% after 30 days; the coating shedding rate is ≤3% after 6 months of storage at room temperature.

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