SEED COATINGS, COATED SEEDS, AND SEED COATING METHODS

Abstract

The aim of the invention is to propose a seed coating which contains iron-based powder and allows the coating state to be easily determined even outdoors and also allows satisfactory coating with rust to be performed, the seed being coated has been coated with the seed coating, and a method of seed coating using the seed coating. The seed coating is used to coat the surface of a seed which contains iron-based powder. The seed coating contains carbon powder with a specific surface area of ​​900 m2 / g or less and the carbon content in the seed coating is 0.6% by mass or greater and 21.0% by mass or less of the iron-based powder.

Description

Seed coating agent, coated seeds, and seed coating method

[0001] The present invention relates to a seed coating agent, coated seeds, and coating method that contain iron powder as a component and can effectively coat seeds.

[0002] With the aging of agricultural workers and the globalization of agricultural product distribution, labor-saving in agricultural work and reduction of agricultural production costs have become issues that need to be resolved. To address these issues, for example, in rice cultivation, direct sowing of seeds in fields is becoming more common, with the aim of eliminating the labor of raising seedlings and transplanting. Among these methods, a technique using coated seeds coated with iron powder to increase seed density has attracted attention because it has the advantages of preventing seeds from drifting or being washed away in paddy fields and preventing bird damage.

[0003] An example of coated seeds coated with iron powder as described above is disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2005-192458

[0005] However, with conventional coating agents that are a mixture of iron-based powder containing iron powder and a binder, it can be difficult to confirm whether the seed surface is covered with the coating agent during the coating process. Therefore, even when the coating process is completed and there are no problems such as rust-covered coated seeds floating on water, the coating state may appear insufficient to the worker, and the worker may determine that the coating is defective. In this case, work is required to improve the coating defect, which creates the problem of prolonged work time. In particular, when working outdoors, it can be difficult to determine whether the seed surface is covered with the coating agent.

[0006] The present invention has been made to solve such problems, and aims to provide a seed coating agent made of iron-based powder that allows easy determination of the coating condition even outdoors and that can effectively coat with rust, coated seeds coated with said seed coating agent, and a method for coating seeds using said seed coating agent.

[0007] The inventors have conducted extensive research to solve the above problems and have come to the following findings.

[0008] As a result of investigating various coatings of iron powder on seeds, it was found that iron-based powder containing a specific carbon powder has the effect of sufficiently concealing the seed surface through coating. It is believed that if the concealing effect is high, rust will easily develop due to the carbon powder covering the seeds, and the covering effect of rust will also be high. In this invention, concealment refers to a state in which the seed surface is so covered that its color cannot be seen.

[0009] [1] A seed coating agent containing iron-based powder used to coat the surface of seeds, having a specific surface area of ​​900 m ２ / g or less carbon powder, wherein the amount of carbon in the seed coating agent is 0.6 mass% or more and 21.0 mass% or less relative to the iron-based powder. [2] The seed coating agent according to [1], wherein the carbon powder is at least one of coconut shell charcoal, bamboo charcoal, wood powder charcoal, peat charcoal, carbon black, activated carbon, graphite, coal, coke, and graphite. [3] A coated seed, the surface of which is coated with the seed coating agent according to [1] or [2]. [4] A seed coating method, in which seeds are coated using the seed coating agent according to [1] or [2].

[0010] By using the seed coating agent of the present invention, it becomes easier to judge whether the coating condition is good or bad during the coating process, and it is possible to promote the spread of rust and effectively conceal the seed surface.

[0011] The seed coating method according to the embodiment of the present invention involves coating the surface of seeds with a seed coating agent containing iron-based powder. Hereinafter, the seeds to be coated and the seed coating agent will be described. In the following description, "%" means "% by mass."

[0012] <Seeds> Rice is preferably used as the target seed of the present invention. There is no particular restriction on the rice variety, and any of japonica, indica, and javanica rice can be used. Rice is often cultivated in paddy fields in hot and humid regions, so the effects of the present invention can be achieved.

[0013] <Seed Coating Agent> Next, the seed coating agent according to the embodiment of the present invention will be described.

[0014] The seed coating agent according to this embodiment contains iron-based powder and is used to coat the surface of seeds.

[0015] <Iron-Based Powder> As the iron-based powder, iron powder, iron oxide powder, and mixtures thereof can be used.

[0016] The iron powder may be pure iron, an ferroalloy, or the like, and is not particularly limited as long as it can provide the effects of the present invention. For example, the ferroalloy may be iron containing Si, Mn, P, S, Cu, Ni, Cr, Mo, V, or Co.

[0017] Examples of methods for producing iron powder include reduction methods that reduce mill scale and atomization methods that spray water or gas at high speeds onto molten steel. Reduced powders such as ore powder, iron-based cuttings, and dust generated during the steelmaking process can also be used. Furthermore, powders of pure iron, iron alloys, iron oxide, and partial iron oxide, as well as mixtures with other metal powders, can be used as iron powders. These are collectively referred to as iron-based powders in the present invention. Combinations of pure iron, iron alloys, iron oxide, and partial iron oxide powders are particularly preferred.

[0018] As the iron oxide powder, iron oxide and partial iron oxide powder can be used. As the iron oxide, magnetite (Fe ３ O ４ ), hematite (Fe ２ O ３ The proportions of each of these materials are not particularly limited as long as they are within the scope of the present invention.

[0019] From an economical viewpoint, iron oxide powder such as mill scale or iron ore is preferably used. Specifically, the iron content (also referred to as total iron) in the iron oxide powder is preferably 60% or more, more preferably 65% ​​or more, and even more preferably 70% or more. The iron content in the iron oxide powder is preferably 98% or less, more preferably 95% or less, and even more preferably 90% or less.

[0020] The iron powder and iron oxide powder can be mixed and used. The metallic iron content of the mixed iron-based powder is preferably 8% or more by mass of the iron-based powder. It is more preferably 10% or more, even more preferably 20% or more, and most preferably 30% or more from the viewpoint of preventing rust. It is most preferably 35% or more, and even more preferably 40% or more. There is no particular upper limit, but the metallic iron content of the mixed iron-based powder is preferably 99% or less, more preferably 98% or less, and even more preferably 95% or less. It is most preferably 90% or less, and most preferably 85% or less.

[0021] The proportion (amount) of iron-based powder contained in the seed coating agent is not particularly limited, but is preferably 5% or more. It is more preferably 10% or more, even more preferably 20% or more, and most preferably 30% or more. The proportion (amount) of iron-based powder contained in the seed coating agent is preferably 99% or less, more preferably 98% or less, and even more preferably 95% or less. It is most preferably 90% or less. The proportion (amount) of iron-based powder contained in the seed coating agent can be calculated using the following formula: Proportion (amount) of iron-based powder contained in the seed coating agent = parts by mass of iron-based powder / (parts by mass of iron-based powder + parts by mass of binder + parts by mass of finishing agent + parts by mass of carbon powder) x 100

[0022] The particle size of the iron-based powder is not particularly specified, but for uniform coating, it is preferable that the proportion of particles of 150 μm or less, as determined by sieving, is 80% or more of the total iron-based powder mass. More preferably, it is 85% or more, and even more preferably, it is 90% or more. There is no particular upper limit, but the upper limit may be 100%. The particle size is the equivalent sphere diameter. The particle size distribution of the iron-based powder can be evaluated by sieving using the method specified in JIS Z2510-2004.

[0023] As the iron-based powder, a mixture of the above-mentioned iron powder, iron oxide powder, and mixture of iron powder and iron oxide powder with other metal powder can also be used. However, from the viewpoint of rust formation, the metallic iron component in the iron-based powder is preferably 8% or more by mass of the iron-based powder. 10% or more is more preferable, and 20% or more is even more preferable. 30% or more is most preferable. 35% or more is even most preferable. 40% or more is even more preferable. There is no particular upper limit, but the metallic iron component in the mixed iron-based powder is preferably 99% or less, more preferably 98% or less, even more preferably 95% or less, most preferably 90% or less, and even most preferably 85% or less.

[0024] <<Carbon powder>> In the present invention, the specific surface area is 900 m ２ It is necessary to contain a specific amount of carbon powder with a specific surface area of ​​800 m or less. The carbon powder preferably contains at least one of coconut shell charcoal, bamboo charcoal, wood powder charcoal, peat charcoal, carbon black, activated carbon, graphite, coal, coke, and graphite. The carbon powder can be preferably used as a single substance or a mixture. ２ / g or less is preferable, and 600m ２ / g or less is more preferable, and 400m ２ The lower limit is not particularly limited, but it is preferably 0.5 m ２ / g or more. ２ / g or more is more preferable, and ２ / g or more is more preferable, and ２ / g or more is most preferable.

[0025] Although the mechanism by which the present invention exerts its effects is unclear, the following reason is considered. Carbon powder is generally black, but it may appear gray outdoors. In this regard, ２ At 900m / g or less, the seed surface appears black even outdoors, making it easy to visually check the coating state. ２When the specific surface area of ​​the carbon powder exceeds 900 m / g, the color tone becomes gray, and it is difficult to visually check the coating state of the seed surface, especially outdoors. ２ / g or less, the fine carbon powder adheres to the seed surface, which is expected to have the effect of promoting the spread of rust.

[0026] The specific surface area can be measured by the BET method using nitrogen. If the raw material is a mixture of carbon powder, iron powder, etc., the iron powder can be removed by magnetic separation or the like and then measured. Furthermore, since iron-based powder has a small specific surface area, it can be measured as is even if it is contained in an amount of 10% or less. The BET method is measured based on JIS Z8830:2013.

[0027] The carbon content in the seed coating agent is set to 0.6% by mass or more relative to the iron-based powder, since it is difficult to determine whether the seed surface is sufficiently concealed if it is less than 0.6% by mass relative to the iron-based powder. It is preferably 0.7% by mass or more, more preferably 2.2% by mass or more, even more preferably 4.2% by mass or more, and most preferably 10.2% by mass or more. Furthermore, since the coating layer tends to become brittle if it exceeds 21.0% by mass, the total carbon content in the seed coating agent is set to 21.0% by mass or less relative to the iron-based powder. It is preferably 19.0% by mass or less, more preferably 18.0% by mass or less, even more preferably 17.0% by mass or less, and most preferably 16.0% by mass or less.

[0028] The amount of carbon in the iron-based powder can be measured in accordance with JIS G 1211-3. In this case, the amount of carbon dissolved in the iron powder and iron oxide powder is included in the amount of carbon in the present invention.

[0029] The particle size of the carbon powder is not particularly limited as long as it does not cause any problems in handling. ５０ The particle size of the carbon powder is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and most preferably 10 μm or less. On the other hand, the lower limit of the particle size of the carbon powder is not particularly limited, but it is preferably about 5 nm from the viewpoint of handling.

[0030] Median diameter D ５０The measurement method is as follows: the carbon powder to be measured is placed in ethanol as a solvent, dispersed by ultrasonic vibration for 30 seconds or more, and the volume-based particle size distribution of the carbon powder particles is measured using a laser diffraction particle size distribution analyzer that uses a laser diffraction / scattering method. The upper limit of the ultrasonic vibration time is not particularly limited, but it is preferably 600 seconds or less. The cumulative particle size distribution is calculated from the obtained particle size distribution, and the particle size of particles equivalent to 50% of the total volume of all particles is determined as the median diameter D ５０ In the present disclosure, this median diameter D ５０ is used as a representative value of the particle size of the carbon powder.

[0031] <Binder> A binder can be used in the present invention. The binder is composed of a sulfate and / or a chloride. Sulfates include calcium sulfate, potassium sulfate, magnesium sulfate, and hydrates thereof. Chlorides include potassium chloride, calcium chloride, magnesium chloride, and hydrates thereof. Calcined gypsum (calcium sulfate hemihydrate) and gypsum (calcium sulfate dihydrate) are particularly preferred. Calcined gypsum and gypsum may be used in the form of a mixture or mixture.

[0032] The mass ratio of the binder to the iron-based powder is not particularly specified, but is preferably 0.1% or more to facilitate the progression of rust. The ratio is more preferably 0.5% or more, even more preferably 1% or more, and most preferably 2% or more. The ratio is also preferably 33% or less. The ratio is more preferably 25% or less, even more preferably 20% or less, and most preferably 15% or less. The mass ratio of the binder to the iron-based powder can be determined by measuring the weights (parts by mass) of the iron-based powder and the binder, respectively, and calculating the ratio of the weight (parts by mass) of the binder to the weight (parts by mass) of the iron-based powder.

[0033] The average particle size of the binder is not particularly specified, but a sphere-equivalent diameter of 1 to 150 μm is preferred. If the average particle size of the binder is less than 1 μm, a large number of agglomerated particles will be generated during the coating process, significantly reducing workability. Therefore, the average particle size of the binder is preferably 1 μm or more in sphere-equivalent diameter, more preferably 2 μm or more, even more preferably 5 μm or more, and most preferably 10 μm or more. On the other hand, if the average particle size of the binder exceeds 150 μm in sphere-equivalent diameter, the adhesive strength to the iron-based powder tends to decrease, resulting in a decrease in the strength of the coating layer. Therefore, the average particle size of the binder is preferably 150 μm or less, more preferably 140 μm or less, even more preferably 130 μm or less, and most preferably 120 μm or less. The average particle size of the binder can be measured using a laser diffraction particle size distribution analyzer (HORIBA LA-950).

[0034] <Coating Amount> While the coating amount for seeds is not particularly specified, it is preferable to set the coating amount of the seed coating agent so that the iron-based powder is 5 to 800 parts by mass per 100 parts by mass of dried seeds. It is preferable to set the iron-based powder to 5 parts by mass or more per 100 parts by mass of dried seeds. To obtain a seed density (specific gravity) sufficient to sink the coated seeds to the bottom of the water, it is more preferable to set the iron-based powder to 10 parts by mass or more, even more preferable to set it to 20 parts by mass or more, and most preferable to set it to 30 parts by mass or more. It is also preferable to set the coating amount of the seed coating agent so that the iron-based powder is 800 parts by mass per 100 parts by mass of dried seeds. The coating amount is more preferably 500 parts by mass or less, even more preferably 400 parts by mass or less, and most preferably 300 parts by mass or less. Incidentally, 5 to 800 parts by mass of iron-based powder per 100 parts by mass of dried seeds is synonymous with having 5 to 800% by mass of iron-based powder.

[0035] <Finishing agent> A finishing agent is not required for coating the seed surface with the seed coating agent, but in order to further prevent the seeds from agglomerating due to oxidation of the iron-based powder, calcined gypsum, gypsum, silica gel, etc. can be preferably used as a finishing agent, and this case is also within the scope of the present invention.

[0036] <Third Component> The seed coating agent of the present invention may contain a third component to the extent that it does not impair the effects of the present invention. The third component includes inevitable impurities and additives intentionally added for some purpose. In either case, the amount of the third component contained is preferably up to about 30% of the seed coating agent. That is, the proportion is preferably 30% or less. The proportion is more preferably 25% or less, even more preferably 20% or less, most preferably 15% or less, and most preferably 10% or less. The lower limit may be 0%. Examples of the third component include pesticides and fertilizers. Specific examples of pesticides include Routine FS (Bayer) and Killap Seed FS (Bayer), and examples of fertilizers include fertilizers containing nitrogen, phosphorus, potassium, etc.

[0037] <Coated seeds and seed coating method> Next, coated seeds and seed coating methods according to embodiments of the present invention will be described below. The coated seeds according to this embodiment are seeds whose surfaces are coated with the seed coating agent according to this embodiment described above.

[0038] The seed coating method according to the present embodiment involves coating the surface of a seed with the seed coating agent according to the present embodiment. The seed coating method according to the present embodiment includes, for example, a step of attaching the seed coating agent to the surface of a seed (hereinafter also referred to as "coating"), and a step of oxidizing the seed coating agent attached to the surface of the seed to form a coating layer.

[0039] There are no particular limitations on the specific method for coating the seed surface with the seed coating agent. For example, as shown in "Iron-Coated Carbohydrate Direct Seeding Manual 2010 (compiled by Kinki Chugoku Shikoku Agricultural Research Center, National Agriculture and Food Research Organization)," any of the methods may be used, including manual coating and a conventionally known method using a mixer.

[0040] Examples of mixers that can be used include impeller mixers (such as Henschel mixers and concrete mixers) and container rotation mixers (such as V-type mixers, double cone mixers, tilt rotation pan mixers, and rotary hoe mixers). Concrete mixers without impellers are also preferred.

[0041] When applying the seed coating agent using these mixers, the iron-based powder and seeds, and optionally a binder, a finishing agent, and additives, may be placed in the mixer, and water may be added as needed. The water may be added by rotating the mixer while spraying water and / or a treatment solution mainly composed of water, or by spraying water as an aqueous solution or suspension.

[0042] The temperature of the water is preferably 5°C or higher, more preferably 10°C or higher, and even more preferably 15°C or higher. The temperature of the water is preferably 40°C or lower, more preferably 35°C or lower, and even more preferably 30°C or lower.

[0043] Although the amount of water to be sprayed in the coating process is not particularly specified, if the amount is less than 10% relative to the mass of the iron-based powder, adhesion to the seeds is insufficient, causing the coating layer to peel off. Therefore, it is preferable to set the amount to 10% or more relative to the mass of the iron-based powder. It is more preferably 12% or more, even more preferably 15% or more, and most preferably 18% or more. On the other hand, if the amount exceeds 1000%, there is a problem of the time required for drying becoming longer. Therefore, it is preferable to set the amount to 1000% or less relative to the mass of the iron-based powder. It is more preferable to set the amount to 500% or less, even more preferably 200% or less, and most preferably 100% or less. Furthermore, since supplying a large amount of water at once causes the seeds to aggregate due to the moisture, it is preferable to limit the amount of water to an amount that allows the seeds to flow in the mixer and to supply it in multiple batches while maintaining the seeds in a wet state. Specifically, the number of times water is supplied is preferably three or more times to control the degree of wetting of the seeds. It is more preferable to supply water four or more times. The upper limit is not particularly limited, but it is preferable to set it to 20 or less times. It is more preferable to supply 18 times or less, and even more preferable to supply 16 times or less. The amount of water supplied at one time is not particularly limited, but is preferably 5% or less of the dry seed weight (parts by mass). It is more preferable to supply 4% or less, and even more preferable to supply 3% or less. The lower limit is not particularly limited, but is preferably 0.5% or more of the dry seed weight (parts by mass). It is more preferable to supply 1% or more, and even more preferable to supply 1.5% or more.

[0044] Regarding the step of forming the coating layer, there is no limitation on the method of oxidizing the seed coating agent. For example, as shown in "Iron-Coated Flooded Direct Seeding Manual 2010 (compiled by Kinki Chugoku Shikoku Agricultural Research Center, National Agriculture and Food Research Organization)," a method of spreading seeds in a seedling tray and sprinkling water on them, or an oxidation method using an oxidation regulator may be applied.

[0045] Water can be supplied either directly to the seeds or in the air, for example, by spraying, atomizing, or adding water to the seeds or the inside of a mixer using a container such as a cup, or by supplying water as humidified air.

[0046] When spraying water in the oxidation process, if a large amount of water is supplied at once, the seeds will clump together due to the moisture, so it is preferable to limit the amount of water to a level that allows the seeds to flow in the mixer and to supply it in multiple batches while maintaining the seeds in a wet state. Specifically, the number of times water is supplied is preferably three or more times to control the degree of seed wetness. The upper limit is not particularly limited, but it is preferable to supply it 20 times or less. The amount of water supplied at one time is not particularly limited, but it is preferably 30% or less of the dry seed mass. Furthermore, the lower limit is not particularly limited, but it is preferable to supply it 5% or more of the dry seed mass. The total amount of water sprayed relative to the dry seed mass is preferably 15% or more. Furthermore, it is preferable that the total amount of water sprayed relative to the dry seed mass is 600% or less.

[0047] When the seed coating agent of the present invention is applied, the seed surface is sufficiently concealed, and rust is easily developed in the subsequent water spray rusting process, resulting in coated seeds with a high rust coating effect.

[0048] An experiment was conducted to confirm the effects of the present invention, and the results will be described below.

[0049] In the experiment, rice seeds were coated with the seed coating agent according to the present invention, and the coated seeds were subjected to an evaluation test.

[0050] Iron powder coating (dust coating) was performed according to the method described in the aforementioned "Iron-Coated Flooded Direct Seeding Manual 2010." Specifically, the process is as follows: First, a seed coating agent was prepared by premixing the seeds (dry rice grains) with the seed coating agent. Using an inclined rotating pan mixer, 100 g of seeds (seed rice grains) were coated with the coating agent in several batches while spraying an appropriate amount of water, and finally, a finishing agent was applied. The coated seeds were then spread on a tray, sprayed with water to oxidize them, and then naturally dried. The seeds were watered four times, with the amount of water supplied each time being 15% of the dry seed weight (parts by mass).

[0051] In the experiment, rice seeds were coated by changing the types and amounts of iron-based powder and carbon powder that make up the seed coating agent, as shown in Table 1. Tables 2 to 5 show the types of each raw material (Table 2: iron powder, Table 3: iron oxide powder, Table 4: binder, Table 5: carbon powder).

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] In Table 1, Examples 1 to 23 were seed-coated using the carbon powder according to the present invention. ２ / g or less of carbon powder was added, so that the carbon content relative to the iron-based powder was 0.6 mass% or more and 21.0 mass% or less. Furthermore, for comparison, seed coating was performed under the conditions of Comparative Examples 1 to 4 shown in Table 1. The particle size of the binder shown in Table 4 is 10 μm or more and 100 μm or less in equivalent sphere diameter. In Table 5, acetylene black and ketjen black are named as above depending on the manufacturing method, but are generally a type of carbon black. The particle size of carbon powders D1 to D9 shown in Table 5 is 5 nm or more and 50 μm or less. Evaluation was performed as follows.

[0058] <Appearance Immediately After Coating> The coating state of the seed surface immediately after coating (hereinafter simply referred to as "coating state") was visually evaluated as follows: "◎" indicates that almost the entire seed was concealed (visual coverage of 95% or more); "○" indicates that some streaks were visible but not a problem (coverage of 80% to less than 95%); "△" indicates that the coating layer was streaky and concealment was insufficient (coverage of 60% to less than 80%); and "×" indicates that most of the seed surface was visible and no concealment was achieved (coverage of less than 60%). As shown in Table 1, Examples 1 to 10 used only iron powder as the iron-based powder and contained carbon powder type D1. The coating state was evaluated as ○ for Examples 1 to 4 and as ◎ for Examples 5 to 10. In contrast, the coating state of Comparative Example 1, which did not use carbon powder, was evaluated as ×, and the coating state of Comparative Example 2, which used carbon powder but had a carbon content of less than 0.6% by mass relative to the iron-based powder, was evaluated as △. This shows that the content of carbon powder affects the coating state, and that within the range of the present invention, the coating state is good.

[0059] Furthermore, the coating state of Examples 11 to 13, which contain iron powder and iron oxide powder as the iron-based powder, was rated as ○, similar to Example 4, which contains the same amount of carbon powder. This shows that the coating state is affected by the carbon content in the seed coating agent, regardless of the type of iron-based powder.

[0060] Furthermore, in Examples 14 to 20, the type of carbon powder was changed in various ways, but the carbon content in all cases was 3.6 mass% relative to the iron-based powder, and the coating state in all cases was rated as ○, similar to Example 4, in which the type of carbon powder was D1 and the carbon content was 3.6 mass% relative to the iron-based powder. This shows that regardless of the type of carbon powder, the coating state is good as long as the carbon content in the coating material is within the range of the invention.

[0061] Furthermore, in Examples 21 to 23, the type of carbon powder was D1, and the mass part of the carbon powder was changed in various ways, but in all cases the carbon content relative to the iron-based powder was kept constant at 4.2 mass%, and the coating state in all cases was rated as ◎, similar to Examples 5 to 10.

[0062] Furthermore, the coating states of Comparative Examples 3 and 4, in which the carbon content was within the range of the present invention but the specific surface area of ​​the carbon powder was outside the range of the present invention, were evaluated as × and Δ, respectively. This shows that the specific surface area of ​​the carbon powder affects the coating state.

[0063] From the above results, the specific surface area is 900 m ２ The results showed that the seed coating agent according to the present invention, which contains a carbon powder of 0.6 mass % or more and 21.0 mass % or less relative to the iron-based powder, can produce iron-coated seeds with a superior appearance immediately after coating compared to conventional techniques. As mentioned above, the carbon content in the iron-based powder can be measured in accordance with JIS G 1211-3.

[0064] The metallic iron content of iron-based powders can be determined as follows. Note that iron powders generally contain 87 to 99% metallic iron, while iron oxide powders do not contain metallic iron. Metallic iron content of iron-based powder (mass %) = (parts by mass of iron powder x (87 to 99) / 100) / (parts by mass of iron powder + parts by mass of iron oxide powder).

[0065] Furthermore, the excellent appearance immediately after coating means that the finely divided carbon powder conceals the seed surface, and it is expected that the finely divided carbon powder will promote the spread of rust, resulting in effective seed coating with rust.

Claims

1. A seed coating agent containing iron-based powder used to coat the surface of seeds, with a specific surface area of ​​900 m ２ / g or less of carbon powder, and the amount of carbon in the seed coating agent is 0.6 mass% or more and 21.0 mass% or less with respect to the iron-based powder.

2. The seed coating agent according to claim 1, wherein the carbon powder comprises at least one of coconut shell charcoal, bamboo charcoal, wood powder charcoal, peat charcoal, carbon black, activated charcoal, graphite, coal, coke and graphite.

3. A coated seed, the surface of which is coated with the seed coating agent according to claim 1 or 2.

4. A seed coating method comprising coating seeds with the seed coating agent according to claim 1 or 2.