Method for producing seed

Abstract

To provide a method for producing a plant seed provided with a coating layer containing iron oxide powder, the coating layer being less prone to peeling or the like when immersed in water.SOLUTION: A method for producing a seed is a method for producing a seed having iron oxide adhered to a surface of a plant seed, the method comprising: a preparation step of preparing a plant seed, powdered or granular iron oxide, and an aqueous coating material containing an oil-affinitive resin functioning as a binder; a coating formation amount determination step of determining a mixed coating formation amount of the aqueous coating material necessary for adhering the iron oxide to the plant seed; and a mixing step of mixing the plant seed, the iron oxide, and the aqueous coating material in the mixed coating formation amount.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing seeds. [Background technology]

[0002] In recent years, a method of rice cultivation called direct seeding, in which rice grains are sown directly into paddy fields, has been developed.

[0003] For direct seeding, a method for producing rice seeds is known in which iron powder (Fe) is attached to the surface of the rice grains and fixed using, for example, gypsum (calcium sulfate) as a binder. By attaching iron powder to the rice grains, the weight of the rice grains is increased, and as a result, when the rice seeds are sown in paddy fields, they settle quickly and are less likely to be washed away by running water.

[0004] Patent Document 1 (JP 2005-192458 A) discloses a method for producing iron-powder coated rice seeds, in which iron powder is adhered to the surface of rice seeds and solidified by promoting the oxidation reaction of metallic iron powder. It also describes the use of calcium sulfate as a binder.

[0005] Patent Document 2 (JP 2019-122269 A) describes a method for producing plant seeds having a coating containing iron oxide powder, and also describes the use of hydrated lime as a binder and PVA (polyvinyl alcohol) as a strength enhancer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-192458 [Patent Document 2] Japanese Patent Application Publication No. 2019-122269 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method for producing iron-powder-coated rice seeds described in Patent Document 1 uses iron powder. The iron powder that adheres to and solidifies on the surface of the rice seeds generates heat through an oxidation reaction, resulting in high temperatures and the risk of the rice seeds dying. Furthermore, a coating consisting of a mixture of binder and iron powder is formed on the surface of rice seeds to which iron powder has been adhered. However, when the iron powder oxidizes and chemically reacts to form iron oxide, it expands, which can cause the coating to crack or peel. To prevent this, after a coating is formed, a binder is again coated on the surface of the rice seeds. Thus, there are issues with the production of coated rice seeds, such as the time-consuming and long manufacturing process.

[0008] In addition, in order to avoid heat generation due to the oxidation reaction of iron powder, the method for producing plant seeds described in Patent Document 2 uses iron oxide (FeO 3、 It is also described that slaked lime (Ca(OH)2) is used as a binder, and that PVA (polyvinyl alcohol) is used to further improve adhesive strength. However, since the slaked lime and PVA used as binders are both water-soluble and have high solubility in water, when rice grains with iron oxide powder attached are immersed in water, the slaked lime and PVA partially dissolve in water, which can cause the iron oxide powder to peel off from the surface of the rice grains. What is needed is a method for producing plant seeds having a coating containing iron oxide powder that is less likely to peel off even when immersed in water. [Means for solving the problem]

[0009] The seed manufacturing method of the present invention is a method for manufacturing seeds in which iron oxide is attached to the surface of plant seeds, and is characterized by including a preparation step of preparing the plant seeds, the powdered or granular iron oxide, and an aqueous paint that functions as a binder and contains an oleophilic resin, a coating amount determination step of determining the amount of mixed coating of the aqueous paint required to attach the iron oxide to the plant seeds, and a mixing step of mixing the plant seeds, the iron oxide, and the mixed coating amount of the aqueous paint.

[0010] In the seed manufacturing method according to the present invention, an aqueous paint that functions as a binder is used, so that even when the plant seeds to which iron oxide has been attached are immersed in water, the iron oxide does not peel off from the surface of the plant seeds and has sufficient adhesion strength. Furthermore, by including a coating amount determination step for determining the amount of mixed coating of the aqueous paint required to attach iron oxide to the plant seeds before the mixing step of mixing the plant seeds, iron oxide, and aqueous paint, the mixing operation in the mixing step can be facilitated and the mixing time can be shortened.

[0011] In addition, in the seed manufacturing method of the present invention, the coating production amount determination process may be characterized by including an iron oxide oil absorption determination process for determining an iron oxide oil absorption amount, which is the amount of water-based paint required to fill the voids between the iron oxide with the water-based paint, and a seed coating production amount determination process for determining a seed coating production amount, which is the amount of water-based paint required to adhere the iron oxide powder to the surface of the plant seed when the iron oxide powder in a state filled with the water-based paint is mixed with the plant seed.

[0012] In the seed manufacturing method of the present invention, the coating production amount determination process includes an iron oxide oil absorption amount determination process and a seed coating production amount determination process, so that the iron oxide oil absorption amount and seed coating production amount can be determined in each process, and therefore the mixed coating production amount of the water-based paint required to adhere iron oxide to the plant seed can be determined more accurately.

[0013] In the seed production method according to the present invention, the iron oxide oil absorption may be determined by mixing the water-based paint with the iron oxide and feeding the water-based paint until the iron oxide forms clumps. This allows the iron oxide oil absorption to be determined accurately and with good reproducibility.

[0014] In the seed production method according to the present invention, the seed coat production amount may be determined by mixing the water-based paint with the iron oxide to form clumps of iron oxide, mixing the plant seeds with the resulting clumps, and then further mixing the water-based paint into the clumps to form individual seeds with the iron oxide adhering to the surface of the plant seeds. This allows the amount of seed coat production to be determined accurately and reproducibly.

[0015] In addition, the seed production method according to the present invention may be characterized in that the mixing step includes a first mixing step of mixing the rice grains with iron oxide powder, and a second mixing step of gradually mixing the water-based paint in an amount that will produce the mixed coating, after the first mixing step. This allows the iron oxide powder to be uniformly attached to the surface of the plant seeds. Furthermore, in the second mixing step, the amount of water-based paint to be mixed can be finely adjusted while observing the state of adhesion of the iron oxide powder to the plant seeds, thereby ensuring the production of desired seeds.

[0016] In the seed manufacturing method according to the present invention, the water-based paint may contain at least one resin selected from the group consisting of a polyacrylic resin, a polyurethane resin, and a polyvinyl acetate resin.

[0017] In the seed manufacturing method according to the present invention, the iron oxide may include at least one of hematite, goethite, and magnetite.

[0018] The seed manufacturing method according to the present invention may further include, after the mixing step, a step of mixing iron oxide powder, a chemical agent, and a water-soluble polyvinyl alcohol resin to adhere the chemical agent to the surface of the seeds.

[0019] In the seed production method according to the present invention, the surface of the plant seeds to which iron oxide has been attached via the aqueous paint can be further coated with a chemical by mixing iron oxide powder, a chemical, and a water-soluble polyvinyl alcohol resin. When the seeds are sown, the chemical is already attached to the surface of the plant seeds, eliminating the need to separately spray the chemical after sowing, thereby reducing the workload of sowing the plant seeds.

[0020] The seed production method of the present invention may be characterized in that the chemicals include herbicides, fungicides used to control pests that harm agricultural crops, insecticides, or growth promoters and germination inhibitors used to promote or inhibit the growth of agricultural crops, etc. [Effects of the Invention]

[0021] In the seed manufacturing method according to the present invention, an aqueous paint that functions as a binder is used, so that even when the plant seeds to which iron oxide has been attached are immersed in water, the iron oxide does not peel off from the surface of the plant seeds and has sufficient adhesion strength. Furthermore, by including a coating amount determination step for determining the amount of mixed coating of the aqueous paint required to attach iron oxide to the plant seeds before the mixing step of mixing the plant seeds, iron oxide, and aqueous paint, the mixing operation in the mixing step can be facilitated and the mixing time can be shortened. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a flowchart illustrating the seed production method according to this embodiment. [Figure 2] FIG. 2 is a diagram for explaining the seed production method according to this embodiment. [Figure 3] FIG. 3 is a diagram illustrating the mixing step according to this embodiment. [Figure 4] FIG. 4 is a diagram illustrating another mixing step according to this embodiment. [Figure 5] FIG. 5 is a diagram illustrating another mixing step according to this embodiment. [Figure 6] FIG. 6 is a diagram illustrating another mixing step according to this embodiment. [Figure 7] FIG. 7 is a diagram illustrating another mixing step according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] In the method for producing a coating on plant seeds according to this embodiment, a coating containing iron oxide powder can be formed on the surface of the plant seeds using an aqueous paint as a binder. The method for producing plant seeds also includes a preparation step, a coating production amount measurement step, a mixing step, and a drying step. The method for producing a coating on plant seeds is described in detail below. In the following description, rice grains are used as the plant seeds, and iron oxide powder is attached to the surface of the rice grains to produce rice grains. However, the present invention is not limited to this, and the method can also be applied to seeds of sesame, adzuki beans, daifuku mochi, peanuts, and other plant seeds in addition to rice grains.

[0024] (Embodiment 1) The method for producing plant seeds according to this embodiment can include a preparation step S001, a coating production amount measurement step S002, a mixing step S003, and a drying step S004. Each step will be described in detail below.

[0025] (1) Preparation process S001 First, the preparation step S001 will be described. In the preparation step S001, rice grains as plant seeds, iron oxide powder, and a water-based paint as a binder are prepared. The rice grains are stored in a dried state after being sorted in salt water. The iron oxide powder is selected from hematite (Fe2O3), goethite (Fe2O3·H2O), or magnetite (Fe3O 4)In this embodiment, magnetite (Fe3O4) having magnetic properties can be used.

[0026] Furthermore, a water-based paint can be used as the binder. In particular, a water-based paint containing a lipophilic resin can be used to prevent peeling of the iron oxide powder when immersed in water. Furthermore, the resin contained in the water-based paint can be an acrylic resin, a urethane resin, a vinyl acetate resin, or a silicone resin.

[0027] Furthermore, it is preferable that the binder used to adhere the iron oxide powder to the surface of the rice grains is in an emulsion state. In an emulsion state, the resin can be uniformly dispersed in the water contained in the water-based paint, thereby allowing the iron oxide powder to be uniformly adhered to the surface of the rice grains. In the case of a water-based paint containing a lipophilic resin, the resin is dispersed in the water in an emulsion state, and an emulsifier is added for this purpose. Therefore, in this embodiment, it is preferable to use a water-based paint containing a lipophilic resin as the binder.

[0028] (2) Film production amount measurement step S002 Next, the step of measuring the amount of produced coating S002 will be described. The step of measuring the amount of produced coating S002 can include a step of determining iron oxide oil absorption S022a and a step of determining the amount of produced seed coating S002b.

[0029] To adhere iron oxide powder to the surface of rice grains, a coating of water-based paint is formed on the surfaces of the rice grains and the iron oxide powder, and the iron oxide powder is then adhered to the rice grains via this water-based paint. In this step, the amount of water-based paint required to adhere the iron oxide powder to the rice grains (hereinafter referred to as the amount of mixed coating) is determined. The method for measuring the amount of mixed coating is described in detail below.

[0030] (a) Iron oxide oil absorption determination process S022a Figure 3 shows a schematic diagram for explaining the method for measuring the amount of mixed coating produced by the aqueous paint. In Figure 3, Figures 3(a) to 3(e) illustrate, in this order, the timing of mixing iron oxide powder, rice grains, and aqueous paint, and the mixing state. The amount of aqueous paint supplied increases from Figure 3(a) to Figure 3(e). First, as shown in Figure 3(a), the iron oxide powder and aqueous paint are mixed, and the aqueous paint adheres to the iron oxide powder, causing the iron oxide powder to aggregate. When additional aqueous paint is mixed, clumps of iron oxide powder form, as shown in Figure 3(b). The amount of aqueous paint supplied at this time is defined as the iron oxide oil absorption. This iron oxide oil absorption can be determined using the following method. For example, the iron oxide oil absorption was measured using 10 g of iron oxide powder as a base. The aqueous paint was added dropwise to 10 g of iron oxide powder while stirring. After that, observe how the voids between the iron oxide particles are filled with the water-based paint, and continue adding and mixing the water-based paint dropwise until the iron oxide and the water-based paint are evenly packed together. The amount of water-based paint added dropwise until the water-based paint is evenly packed together can be determined as the iron oxide oil absorption.

[0031] In this embodiment, the water-based paints used were Nippe Sealer manufactured by Nippon Paint Co., Ltd., which is an acrylic resin-containing water-based paint, and acrylic / silicon resin-containing water-based paint (Water-based Paint Clear manufactured by Asahi Paint Co., Ltd.).

[0032] In this embodiment, the iron oxide oil absorption per 10 g of iron oxide powder was 1.9 ml in volume (2.1 g in weight) for the acrylic resin-containing water-based paint, and approximately 3.1 ml in volume (approximately 3.6 g in weight) for the acrylic-silicone resin-containing water-based paint.

[0033] The iron oxide powder can be used in powder or particulate form. The iron oxide powder is approximately spherical, and the particle size can be sieved using a sieve or the like to a predetermined particle size or less (for example, a diameter of 100 μm or less). In this embodiment, iron oxide powder with a particle size of approximately 45 μm or less can be used.

[0034] (b) Seed coating production amount determination step S002b Next, as shown in Figure 3(c), a predetermined amount of rice grains is mixed with the iron oxide powder balls. In this state, the rice grains adhere to the iron oxide powder balls. Next, as shown in Figure 3(d), water-based paint is added dropwise while mixing. As the iron oxide balls gradually separate, the water-based paint spreads between the iron oxide powder particles and onto the surface of the rice grains. This spread water-based paint causes the iron oxide powder to adhere to the rice grains. Next, as shown in Figure 3(e), water-based paint is added dropwise and mixed, forming a coating of the iron oxide powder and water-based paint on the surface of the rice grains. This coating forms individual grains of rice grains. The amount of water-based paint added after mixing the iron oxide powder balls with the rice grains described above can be defined as the rice grain coating amount.

[0035] 3(d) shows the state in which iron oxide is attached to the surface of rice grains via the aqueous paint, and therefore the amount of mixed coating film produced can be calculated as the sum of the iron oxide oil absorption amount and the rice grain coating film production amount. Note that the rice grain coating film production amount in this embodiment corresponds to the seed coating film production amount.

[0036] Since rice grains vary in shape, particle size distribution, surface condition, etc., these variations must be taken into consideration when measuring the amount of rice grain film formation. In this embodiment, rice grains of a typical variety, shape, and particle size distribution were prepared and used as standard rice grains, and the amount of rice grain film formation was measured for these standard rice grains. The surface of the rice grains used was dried, for example, at room temperature for three days.

[0037] In this embodiment, the following rice grains were selected as standard rice grains. (1) Rice variety: Koshihikari (produced in Toyama) (2) Processing of rice grains: Rice grains that have been dried at room temperature for three days after salt water selection are used.

[0038] Next, as an example, we will explain the amount of coating produced by a water-based paint when iron oxide powder is attached to the standard rice grains described above to produce magnetic rice grains. An acrylic resin-containing water-based paint (Nippe Sealer, manufactured by Nippon Paint Co., Ltd.) was used as the water-based paint.

[0039] Figure 4 shows the coating formation process when iron oxide powder is applied to the standard rice grains to produce coated seeds (magnetic rice grains). As shown in Figure 4, for example, 10 g of iron oxide powder is mixed with the water-based paint with the iron oxide oil absorption rate described above, forming an agglomerated state of the iron oxide powder (Figure 4(a)). Next, water-based paint is added and mixed to form balls (Figure 4(b)). 20 g of standard rice grains are mixed with these balls of iron oxide powder, and the water-based paint is added dropwise while mixing (Figure 4(c)). As the iron oxide balls gradually separate, the water-based paint spreads between the iron oxide powder and onto the surface of the rice grains. This spread water-based paint causes the iron oxide powder to adhere to the rice grains. Furthermore, by adding water-based paint dropwise and mixing, a coating of iron oxide powder and water-based paint is formed on the surface of the rice grains, and individual grains of rice grains with this coating are formed (Figure 4(d)). From the above, the amount of rice grain coating produced was calculated. When 20 g of the above standard rice grains were mixed with the water-based paint, the amount of rice grain coating produced was 1.4 ml in volume (1.5 g in weight). Based on the above, when using an acrylic resin-containing water-based paint (Nippe Sealer manufactured by Nippon Paint Co., Ltd.), the amount of mixed coating produced by the water-based paint when 20 g of standard rice grains are mixed with 10 g of iron oxide powder can be determined to be 3.3 ml in volume (3.6 g in weight).

[0040] (3) Mixing process S003 Next, the mixing step S003 in which rice grains, iron oxide powder, and water-based paint are mixed together and the iron oxide powder is adhered to the surface of the rice grains will be described in detail. In this embodiment, a mixing step in which the mixing ratio (weight ratio) of rice grains to iron oxide powder is fixed at about 2:1 will be described. Since the rice grains with the iron powder adhered to them sink in water, the ratio (weight ratio) of rice grains to iron oxide powder can be set to about 1:0.1 to 1:0.75.

[0041] In this embodiment, the rice grains and iron oxide powder are mixed in a ratio of, for example, 20 g of rice grains and 10 g of iron oxide powder. The rice grains used were the standard rice grains. A water-based paint with the mixed film formation amount determined in the film formation amount measurement step S002 is also prepared. In this embodiment, the water-based paint used was Nippe Sealer, an acrylic resin-containing water-based paint manufactured by Nippon Paint Co., Ltd.

[0042] Next, as shown in Figure 5, 20 g of the prepared rice grains, 10 g of iron oxide powder, and 3.3 ml (milliliters) of water-based paint with a combined oil absorption capacity can be mixed all at once while stirring. In Figure 5, Figure 5(a) shows the state of the rice grains, water-based paint, and iron oxide powder agglomerated by mixing the rice grains, iron oxide powder, and water-based paint all at once. Figure 5(b) shows the state of the agglomerated rice grains, water-based paint, and iron oxide powder after further mixing and stirring. Figure 5(c) shows the state of a single grain of rice grain with a coating of the mixed iron oxide powder and water-based paint formed on the surface of the rice grain. The mixing time can be approximately 5 to 10 minutes. After mixing the rice grains, iron oxide, and water-based paint, the iron oxide powder adhered evenly to the rice grains, and no adhesion between the grains was observed. This allows the iron oxide powder to adhere evenly to the rice grains, forming individually separated rice grains. Furthermore, after the iron oxide powder was applied to the surface of the rice grains, the rice grains with the iron oxide powder attached were held in the hand to check the condition of the rice grains with the iron oxide powder attached. As a result, when the iron oxide powder was applied to the surface of the rice grains using the above method, no iron oxide powder adhered to the palm of the hand even when the rice grains with the iron oxide powder attached were held in the hand, confirming that the iron oxide powder was attached to the surface of the rice grains in good condition.

[0043] Furthermore, if the amount of water-based paint mixed is insufficient, sufficient adhesion may still not be achieved. In this state, the water-based paint does not sufficiently surround the iron oxide powder attached to the rice grains, resulting in an uneven surface. In this case, adding a small amount of water-based paint allows the water-based paint (acrylic resin) to sufficiently surround the iron oxide powder, improving the adhesion of the iron oxide powder to the rice grain surface. In this state, the surface unevenness of the rice grains to which the iron oxide powder has adhered becomes smaller, and a gloss can be seen. This allows the iron oxide powder to adhere evenly to the rice grains, forming individually separated rice grains. This is called magnetic rice grains.

[0044] Furthermore, if the amount of iron oxide powder mixed is relatively insufficient, for example, the amount of water-based paint mixed in will be excessive, resulting in a muddy mixture of rice grains and iron oxide powder. In this case, iron oxide powder can be mixed in little by little. While observing the mixed state, further mixing can be performed, gradually changing from a state in which the rice grains are sticking together to a state in which no sticking between the rice grains is observed. This allows the iron oxide powder to adhere evenly to the rice grains, resulting in the formation of individually separated magnetic rice grains.

[0045] Figure 6 shows the formation of individual grains of rice with a coating when water is first sprayed onto the surface of the rice grains to facilitate adhesion of the iron oxide powder to the rice grains, and then the iron oxide powder and rice grains are mixed together. Figure 6(a) shows the state after water has been sprayed onto the surface of the rice grains. Figure 6(b) shows the state after iron oxide powder is mixed into the water-covered rice grains, resulting in the iron oxide powder adhering to the rice grains' surfaces. Figure 6(c) shows the state after water-based paint has been added and mixed with the rice grains with iron oxide powder adhering to their surfaces. Figure 6(d) shows the state after water-based paint is added dropwise and mixed. The water-based paint spreads, and the iron oxide powder adheres evenly to the rice grains' surfaces. Next, as shown in Figure 6(e), by adding water-based paint dropwise and mixing, a coating of iron oxide powder and water-based paint is formed on the surface of the rice grains, resulting in single grains of rice grains coated with this coating. As shown in Figure 6, in order to facilitate adhesion of the mixed iron oxide powder to the surface of the rice grains, it is possible to first spray approximately 0.4 ml (0.4 mg, ratio to rice grain weight: 2%) of water onto the surface of the rice grains before mixing the iron oxide powder into the rice grains, and then mix the iron oxide powder with the rice grains. This is preferable because it facilitates adhesion of the iron oxide powder to the surface of the rice grains.

[0046] Figure 7 shows another method for mixing rice grains, iron oxide powder, and water-based paint. Figure 7(a) shows the state in which iron oxide powder is mixed with rice grains and adhered to the surface of the rice grains. Figure 7(b) shows the state in which water-based paint is further mixed. Figure 7(c) shows the state in which water-based paint is further added and mixed with the rice grains with iron oxide powder adhered to their surface. The water-based paint spreads, and the iron oxide powder adheres uniformly to the surface of the rice grains. Next, as shown in Figure 7(d), water-based paint is further added dropwise and mixed, forming a coating of the iron oxide powder and water-based paint mixed on the surface of the rice grains, resulting in single grains of rice grains coated with this coating. This mixing method is described in detail below. First, 20 g of rice grains and 10 g of iron oxide powder are placed in a mixing container and stirred (Figure 7(a)). After that, 3.3 ml of water-based paint with an oil absorption capacity can be mixed in completely while stirring. Alternatively, the water-based paint can be mixed in while observing the state of the iron oxide powder adhering to the surface (Figure 7(b)). In this case, the iron oxide powder adhered evenly to the rice grains, without any adhesion or clumping. Furthermore, if the amount of water-based paint mixed is insufficient, adding a small amount of water-based paint, as described above, can be performed to ensure that the water-based paint is fully dispersed around the iron oxide powder, improving its adhesion to the rice grain surface. In this state, the surface irregularities of the rice grains with the iron oxide powder attached are reduced, and a glossy appearance can be observed. It is also possible to mix the water-based paint in multiple steps. For example, the water-based paint can be mixed in twice, first by mixing 2.0 ml of water-based paint and stirring until the rice grain surface begins to dry. Then, 1.3 ml, equivalent to the remaining oil absorption of the water-based paint to be mixed, was added and mixed while stirring. As a result, the iron oxide powder adhered evenly to the rice grains, with no adhesion or clumping observed (Figure 7(c)).

[0047] In this method of gradually mixing a predetermined amount of water-based paint after mixing the rice grains with iron oxide powder, the amount of water-based paint can be finely adjusted while observing the state of adhesion of the iron oxide powder to the rice grains. For example, while gradually mixing in the water-based paint to adhere the iron oxide powder to the surface of the rice grains, the rice grains with the iron oxide powder attached thereto can be grasped in the hand midway through the process to confirm that no iron oxide powder adheres to the palm of the hand, thereby making it possible to confirm that the iron oxide powder has adhered to the surface of the rice grains in a good condition.

[0048] As a result, it is possible to reliably and reproducibly form individually separated rice grains with iron oxide powder adhering to the surface of the rice grains (Fig. 7(d)). It also avoids the risk of adding too much water-based paint.

[0049] Another method for mixing rice grains, iron oxide powder, and aqueous paint is to prepare in advance 10 g of iron oxide powder mixed with aqueous paint having an amount equal to or greater than the iron oxide oil absorption amount but less than the amount required to produce a mixed coating, and then mix this iron oxide powder mixed with aqueous paint with a predetermined amount of rice grains (20 g of rice grains in this embodiment).This method is easy to handle because the iron oxide powder mixed with aqueous paint is prepared in advance, and when sowing the rice grains, the iron oxide powder mixed with aqueous paint is mixed with the corresponding predetermined amount of rice grains to produce magnetized rice grains.

[0050] Next, the detection of the end point of the mixing process will be described. As explained above, after mixing rice grains, iron oxide powder, and aqueous paint, or during the mixing process, the state of the iron oxide powder adhering to the surface of the rice grains can be confirmed by squeezing the rice grains with iron oxide powder attached in one's hand and checking whether rice grains or iron oxide powder adhere to the palm of one's hand. If the amount of aqueous paint mixed in is appropriate after mixing rice grains, iron oxide powder, and aqueous paint, neither rice grains nor iron oxide powder will adhere to the palm of one's hand even when the rice grains with iron oxide powder attached are squeezed in one's hand. The mixing process can be terminated in this state.

[0051] On the other hand, if too much water-based paint is mixed after mixing the rice grains, iron oxide powder, and water-based paint, the excess water-based paint may bind the rice grains together, causing clumps of rice grains to stick to the palm of the hand. In this case, the amount of iron oxide powder to be mixed can be fine-tuned by adding and mixing. In this case, the rice grains with iron oxide powder attached can be held in the hand, and iron oxide powder can be mixed in until the rice grains no longer stick to the palm of the hand, at which point the mixing process can be completed.

[0052] Furthermore, if the amount of water-based paint mixed in is small after mixing rice grains, iron oxide powder, and water-based paint, iron oxide powder that does not adhere to the surface of the rice grains may adhere to the palm of the hand. In this case, the amount of water-based paint to be mixed can be fine-tuned by adding more water-based paint and mixing. In this case, the rice grains with iron oxide powder attached can be held in the hand, and water-based paint can be mixed in until the rice grains no longer adhere to the palm of the hand, completing the mixing process.

[0053] Before the mixing process of mixing the rice grains, iron oxide powder, and water-based paint, a coating process can be added to form a thin coating of water-based paint on the surface of the rice grains. In this embodiment, 1.4 ml of water-based paint, equivalent to the amount of rice grain coating required, was mixed with the rice grains to form a water-based paint coating on the surface of the rice grains. Mixing 1.4 ml of water-based paint, equivalent to the amount of rice grain coating required, with the rice grains forms a thin film of water-based paint on the surface of the rice grains, but excess water-based paint that does not contribute to film formation falls off the rice grains during mixing. By forming a water-based paint coating on the surface of the rice grains, the rice grains can be protected from rubbing against each other and damaging the rice grains when mixed with iron oxide powder in the subsequent mixing process.

[0054] (4) Drying process S004 Next, the drying step S004 performed after the mixing step will be described in detail. In the mixing step, iron oxide powder is attached to the surface of the rice grains using a water-based paint as a binder, and then the rice grains are spread on a sheet and, for example, dried naturally. Within a few hours, the magnetically treated rice grains with the iron oxide powder attached are completed. Note that the drying may be performed using a dryer or the like, for example, by forcibly drying the rice grains at a low temperature of 40 degrees or less to protect them. Through the above steps, the magnetically treated rice grains are completed.

[0055] (5) Drug coating process S005 In this embodiment, after producing the magnetized rice grains by the above-mentioned method, a chemical coating step S005 can be included in which the surface of the magnetized rice grains is further coated with a chemical such as an agricultural chemical. The chemical coating step will be described in detail below.

[0056] First, magnetized rice grains were prepared using the above-described method. In this embodiment, the magnetized rice grains were produced using an acrylic-based water-based paint called "Nippon Primer Sealer" as the binder. Next, the magnetized rice grains were mixed with iron oxide powder, pesticides, and polyvinyl alcohol (PVA) in a container and stirred. As a result, a PVA film containing the chemicals was formed on the surface of the magnetized rice grains. The PVA functions as a binder. While iron oxide powder was used in this embodiment, any material that does not react with pesticides or other chemicals can be used. For example, titanium oxide, silica, gypsum, zinc oxide, etc. can be used. In this embodiment, 6 g of iron oxide powder, 0.9 g of PVA, and the chemicals were mixed with 30 g of magnetized rice grains to form a PVA film containing the chemicals on the surface of the magnetized rice grains. Examples of the chemicals include herbicides, pesticides such as fungicides and insecticides used to control pests that damage agricultural crops, growth promoters and germination inhibitors used to promote or inhibit the growth of agricultural crops, etc. In this embodiment, Kaneyonol PVA (PVA content: 8%) manufactured by Kaneyo Soap Co., Ltd. was used as the PVA. Two types of herbicide can be used: a rice herbicide flowable manufactured by Sumitomo Agro Manufacturing Co., Ltd. (ingredients: imazosulfuron, pyraclonil, benzobicyclon, emulsifier, water (90%)), and a herbicide (Clincher EW) manufactured by Dow AgroSciences Co., Ltd. (ingredients: cyhalofop butyl emulsion). The amount of herbicide to be mixed in can be calculated based on the amount of rice grains contained in the magnetic rice grains, depending on the herbicide used. Specifically, 2.5 ml of the herbicide manufactured by Sumitomo Agro Manufacturing Co., Ltd. was added, and 0.5 ml of the herbicide manufactured by Dow AgroSciences Co., Ltd. was added. The grains are then dried at room temperature for, for example, three days, resulting in magnetic rice grains coated with the herbicide, in which a PVA film containing the herbicide is formed on the surface of the magnetic rice grains.

[0057] The above-mentioned coated magnetic rice grains were immersed in a water tank at 21°C, and the elution of the PVA coated surface and the germination of the magnetic rice grains were observed. For herbicides manufactured by Sumitomo Agro Manufacturing Co., Ltd. and Dow AgroSciences, elution began about three days after immersion, and was completely eluted after five days. Furthermore, germination from the magnetic rice grains was confirmed about four days after immersion. This confirmed the effectiveness of the coated magnetic rice grains. [Example]

[0058] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. Furthermore, the magnetic rice grains according to Examples 1 to 3 and Comparative Example were produced using the plant seed production method described in this embodiment. Before describing the examples and comparative example of the plant seed production method, the iron oxide powder used in these examples and an example of the aqueous paint used as a binder will be described below.

[0059] (Selection of iron oxide powder) The iron oxide powder used in this example is magnetite (Fe3O4). The iron oxide powder can be used in powder form. The average particle size (diameter) of the iron oxide powder used is 100 μm or less. The average particle size (diameter) of the typical iron oxide powder used is 45 μm or less. The commercially available black pigment (model HY-335) manufactured by Kagyo Co., Ltd. and Bayferrox® (model Bayferrox318) manufactured by Lancs Co., Ltd. are used as the iron oxide (magnetite, Fe3O4). Hematite (Fe2O3) and / or goethite (Fe2O3·H2O) may be mixed in a predetermined ratio with the iron oxide (magnetite, Fe3O4) as an auxiliary agent for color adjustment.

[0060] (Selection of binder) Next, we will explain in detail the water-based paint used as a binder. First, to confirm the types of water-based paints that can be used as binders, or the types of resins contained in water-based paints, several commercially available water-based paints were selected and the following trial experiments were conducted. The search for a material that has affinity with the iron oxide of the magnetic material, and that forms a flexible coating when water evaporates, making it water-repellent, resulted in a water-based paint made of polymer resin. As polymers that are water-repellent and become flexible after water evaporates, we used a combination of polyacrylate, polyurethane, polyvinyl acetate, and silicone resins.

[0061] As an example of a method for producing a coating for plant seeds, the following physical property requirements for the binder required when producing magnetized rice grains by adhering iron oxide powder to rice grains can be listed: It is envisioned that the plant seeds or rice grains produced by the plant seed production method according to this embodiment will be directly sown using a seeder, for example, by moving the magnetized plant seeds or rice grains using a magnet. (1) It is water-repellent and prevents swelling due to water soaking. (2) The film formed on the surface of rice grains as a binder is flexible and does not crack or peel off even when a seed drill is used. (3) It adheres well to rice grains and, when soaked in water, does not peel off for at least the number of days required for germination to begin after soaking the grains. Normally, the average number of days required for germination to begin after soaking rice grains in water is about 7 days, depending on the temperature. (4) It does not affect the germination and growth of rice grains. (5) It has good affinity with the iron oxide (magnetite) that is attached to the surface of rice grains.

[0062] The following commercially available water-based paints were selected as binders, and experiments were conducted to confirm whether they met the physical property requirements for the binders described above. In particular, it is preferable for the paints to contain a resin that is water-repellent and flexible enough to deform to a certain extent after the water evaporates. For this reason, water-based paints containing oleophilic resins were selected: acrylic resin, acrylic-urethane resin, acrylic-silicone resin, and vinyl acetate resin. 1. Water-based paint containing acrylic resin (1) Atom Support water-based paint (product name: Free Coat) (2) Nippon Paint water-based paint (product name: Nippe Sealer) 2. Water-based paint containing acrylic and urethane resin (3) Water-based paint manufactured by Washin Paint Co., Ltd. (product name: water-based urethane varnish) 3. Water-based paint containing acrylic and silicone resin (4) Atom Paint water-based paint (product name: All Mighty Neo) (5) Water-based paint made by Asahipen Co., Ltd. (super versatile) 4. Vinyl acetate resin-containing water-based paint (6) Cemedine water-based paint (for woodworking)

[0063] First, using the water-based paint, rice grains and iron oxide powder were mixed to create magnetic rice grains, and it was confirmed whether the physical property requirements of the binder were met. Note that the vinyl acetate resin-containing water-based paint is highly viscous, so it was diluted with approximately 10% water before mixing. The mixing time was approximately 10 minutes. After mixing, the magnetic rice grains were produced by spreading them on a sheet and drying them for several hours.

[0064] Tests were conducted to confirm the physical properties of the magnetically modified rice grains produced using the six water-based paints. First, 25 grains of each magnetically modified rice grain were placed in a wire mesh container and placed in water at a temperature of 19-21°C. The grains were then observed for peeling. Germination began two days after immersion, germinated four days later, and by six days after immersion, both the stems and roots had grown to over 2 cm. By 12 days after immersion, the roots had branched out into about three new branches and reached over 5 cm in length. Furthermore, the stems had grown to over 3 cm and formed two or more leaves, and no significant problems were observed with rice plant growth. During this period, none of the magnetically modified rice grains exhibited any peeling. From the above experiments, it was found that water-based paints containing acrylic resin, acrylic-urethane resin, acrylic-silicone resin, and vinyl acetate resin can be used as binders for magnetic rice grains.

[0065] Example 1 Next, Example 1 will be described in detail, in which magnetic rice grains were produced using aqueous coating materials containing acrylic resin, acrylic-urethane resin, acrylic-silicone resin, and vinyl acetate resin, as confirmed in the above experiments. The method for producing magnetic rice grains in Example 1 can include a step of measuring iron oxide oil absorption, a step of measuring rice grain coating production, a mixing step, and a drying step. Each step will be described below.

[0066] (Iron oxide oil absorption measurement process) As mentioned above, iron oxide oil absorption can be defined as the amount of water-based paint supplied when the voids between the iron oxide powder are just filled with the binder (resin) and the iron oxide and water-based paint are evenly packed together. The iron oxide oil absorption was measured for water-based paints containing the above-mentioned acrylic resin, acrylic-urethane resin, acrylic-silicone resin, and vinyl acetate resin. Iron oxide oil absorption was calculated by converting the amount of oil absorbed per 100 g of iron oxide powder.

[0067] The measurement results of the oil absorption of each water-based paint are shown in Table 1. The actual measured values ​​of the solid content and water content of each water-based paint are also shown.

[0068] [Table 1]

[0069] The solids and moisture content in the above measurement results are primarily actual measurements. It is believed that among the water-based paints tested above, those with a high solids content contain, in addition to the resin, an emulsifier and a white pigment (such as titanium oxide) or silica. To measure the solids and moisture content, a fixed amount of the water-based paint to be tested was taken and left at room temperature for a week to evaporate the moisture. After the moisture had fully evaporated, the weights before and after evaporation were weighed, and the weight after evaporation was determined as the solids content, while the difference between the weights before and after evaporation was determined as the moisture content.

[0070] As shown in Table 1, the oil absorption capacity varies depending on the type of resin contained in each water-based paint, its composition ratio, and the amount of solids. Therefore, it is necessary to measure the iron oxide oil absorption capacity for each water-based paint.

[0071] (Rice rice coating production amount measurement process) As described in the first embodiment, a predetermined amount (20 g) of rice grains is mixed with iron oxide powder that has been mixed with the water-based paint to form balls. The water-based paint is gradually added dropwise while mixing until a coating of the iron oxide powder and water-based paint mixed together forms on the surface of the rice grains (see Figure 3(d)). At this time, individual grains of rice grains with this coating are formed. The amount of water-based paint supplied after the rice grains are mixed with the iron oxide powder balls is defined as the amount of rice grain coating produced.

[0072] As an example, we measured the amount of film formed on rice grains when an acrylic resin-containing water-based paint (Nippe Sealer, manufactured by Nippon Paint Co., Ltd.) was used as the water-based paint. For example, when 20 g of the above-mentioned standard rice grains were mixed with 10 g of iron oxide powder balls mixed with the water-based paint with the above-mentioned iron oxide oil absorption amount, the amount of film formed on the rice grains by the water-based paint was 1.4 ml in volume (1.5 g in weight).

[0073] As a result, the iron oxide oil absorption amount measured for each of the above water-based paints and the rice grain coating amount were measured, and the sum of these was calculated as the amount of mixed coating produced.When using an acrylic resin-containing water-based paint (Nippe Sealer manufactured by Nippon Paint Co., Ltd.), the amount of mixed coating produced by the water-based paint when 20 g of standard rice grains are mixed with 10 g of iron oxide powder can be calculated as 3.3 ml in volume (3.6 g in weight).

[0074] (Mixing process) Next, a mixing step was carried out to mix rice grains, iron oxide powder, and water-based paint. In this example, as an example, we will explain the case where an acrylic resin-containing water-based paint (manufactured by Nippe Home Products Co., Ltd., product name "Nippe Primer Sealer") was used among the six types of water-based paints mentioned above. Similar results were obtained when other water-based paints were used.

[0075] The mixing methods tested were a one-time mix and a separate mix, and the results are described below. (Mix 1) When mixed at once: 20 g of rice grains, 10 g of iron oxide powder, and 3.3 ml (milliliters) of water-based paint with an oil absorption capacity were mixed in all at once while stirring. (Mixing 2) When water-based paint is mixed gradually In this example, 20 g of rice grains, 10 g of iron oxide powder, and 2.1 g of acrylic resin-containing water-based paint (oil absorption capacity 21 g / 100 g) were first prepared. The rice grains and iron oxide powder were then mixed, followed by the water-based paint. The oil absorption amounts shown above are those calculated ignoring the adhesion of the water-based paint to the rice grain surface; therefore, the actual oil absorption amounts are slightly higher. If the amount of water-based paint is insufficient as a result of the mixing, and the iron oxide powder does not adhere sufficiently to the rice grain surface, the water-based paint (acrylic resin) will not fully wrap around the iron oxide powder adhered to the rice grain, resulting in an uneven surface. In this case, adding a small amount of water-based paint will allow the water-based paint (acrylic resin) to fully wrap around the iron oxide powder, improving the adhesion of the iron oxide powder to the rice grain surface. In this state, the surface of the rice grain with the iron oxide powder attached becomes less uneven, and a glossy appearance can be observed.

[0076] In order to make it easier for the iron oxide powder to adhere to the surface of the rice grains, when mixing the iron oxide powder into the rice grains, first spray about 0.4 ml of water (2% of the rice grain weight) onto the surface of the rice grains, and then mix the iron oxide powder with the rice grains.

[0077] Both Mix 1 and Mix 2 produced good magnetic rice grains.

[0078] (drying process) After mixing the rice grains, iron oxide powder, and water-based paint using the method described above, the mixture was spread on a sheet and left at room temperature (25°C) to dry for about 2 to 3 hours, thereby obtaining magnetized rice grains.

[0079] Next, a soaking test was conducted to examine the germination and growth of the magnetized rice produced by the above method. First, magnetized rice was produced using nine types of water-based paint, including the above-mentioned acrylic resin, acrylic-urethane resin, acrylic-silicone resin, and vinyl acetate resin. Next, 25 grains of magnetized rice were extracted for each water-based paint used, placed in a wire mesh container, and placed in water. The water temperature was controlled between 24.6°C and 28°C, and the seeds were soaked for six days and observed.

[0080] The results of the seed soaking test are shown in Tables 2 and 3. Table 2 shows the change in the number of germinations six days after soaking. Table 3 shows the change in the average stem length (mm) and the number of roots (roots) five and six days after soaking.

[0081] [Table 2]

[0082] [Table 3]

[0083] As shown in Table 2, germination of all magnetized rice seeds was completed by day 6. This indicates that the resin system has no effect on germination or the growth of the germinated seeds.

[0084] Furthermore, as shown in Table 3, the stem length of all the magnetized rice grains produced using the nine types of water-based paint tested was in the range of 15-18 mm.

[0085] The above-mentioned soaking test revealed that when magnetic rice grains were produced using water-based paints containing the above-mentioned acrylic resins, acrylic-urethane resins, acrylic-silicone resins, and vinyl acetate resins as binders, there was no effect on germination and germination growth, or on the growth of stems and roots.

[0086] The magnetized rice produced in this example is used for direct seeding cultivation, in which rice grains are sown directly in paddy fields. Because the magnetized rice grains produced in this example are magnetic, they can be attached to a magnet, transplanted, and sown. For example, we investigated whether germinated magnetized rice grains can be attached to a magnet. Experiments confirmed that the magnetized rice grains produced in this example can be sufficiently attached to a magnet. Permanent magnets with adhesive forces of 1.2 kg and 4.5 kg were used. Thus, even with soaked germinated rice grains with weak sprouts, the magnetized rice grains produced in this example can be attached to a magnet, transplanted, and sown.

[0087] Example 2 It has also been found that the strength of the coating formed on the surface of rice grains is related to the resin concentration in the water-based paint, with the strength of the coating decreasing when the resin concentration in the water-based paint is low. Next, the amount of iron oxide powder added was kept constant, and the water-based paint was diluted with water to examine the effect on the strength of the coating when the resin concentration in the water-based paint was reduced. Two types of urethane varnish, a transparent clear acrylic urethane resin varnish and an acrylic resin water-based varnish for woodworking, from Washin Paint Co., Ltd. were used, and the required water-based paints were prepared by changing the amount of resin as shown below.

[0088] [Table 4]

[0089] 20g of rice grains were mixed with 10g of iron oxide powder, and once the iron oxide powder had adhered to the surface of the rice grains, each of the above water-based paints was added dropwise while mixing in small amounts until a coating was formed. Even when the solid content was diluted to approximately 10%, as described above, a coating was still formed. These samples were spread on a sheet and dried at room temperature for three days, after which 25 grains were immersed in a constant temperature water bath (24-25°C) to observe the peeling of the coating and germination. Germination and peeling test results, number of samples: 25 seeds

[0090] [Table 5]

[0091] From the above results, it was found that the acrylic urethane resin and acrylic resin used tend to peel more as the solid content decreases. This is thought to be due to the fact that the amount of resin is small per 10g of iron oxide powder, resulting in a thinner coating and lower strength.

[0092] Next, we investigated the relationship between the coating strength and peeling rate due to changes in the concentration (amount of resin) of the water-based paint and the amount of iron oxide powder added. Nippon Paint's Nippe Primer Sealer was diluted with water at 1:1 and 1:3 ratios, and 20g of rice grains were mixed with 10g, 8g, and 2g of iron oxide powder. The diluted water-based paint was then added dropwise to create the desired magnetic rice grains. The coating yields were 2.7ml for 10g of iron oxide powder at 1:1 ratio, 2.6ml for 8g, and 1.9ml for 2g. The coating yields were 1.9ml for 10g, 1.6ml for 8g, and 1.0ml for 2g at 1:3 ratio. Since the solids content of the original solution was approximately 41%, the solids content was approximately 21% at a 1:1 ratio and approximately 10% at a 1:3 ratio. The magnetized rice grains were spread on a sheet and dried at room temperature for three days, after which 25 grains each were placed in a wire mesh container and immersed in a water tank at 23-25°C to observe germination and peeling, and the following results were obtained.

[0093] [Table 6]

[0094] As shown in Table 6, germination was favorable regardless of the solid content or iron oxide powder. When the solid content was 21%, there was no peeling, regardless of the amount of iron oxide powder. When the solid content was low at 10%, the amount of coating film relative to the iron oxide powder was reduced, resulting in a decrease in coating strength. At 10g and 8g, there was no apparent peeling by the 9th day, but slight peeling occurred when rubbing strongly with a finger. At 2g, there was sufficient solid content and no peeling occurred. Considering these results in the same way as in Example 1, it is possible to maintain coating strength for water-based paints with solid contents of 10% or less by reducing the amount of iron oxide powder added to 2g or less.

[0095] In the above examples, black magnetite was primarily used as the iron oxide. However, seed production methods using other iron oxides were also investigated through experiments. For example, red hematite was used as the iron oxide powder to investigate the conditions for coating formation. The red iron oxide powder used was commercially available HY-130 manufactured by Kagyoku Co., Ltd., and the water-based paint used was Nippe Primer Sealer manufactured by Nippon Paint Co., Ltd. 10 g of red iron oxide powder was weighed, mixed and stirred while adding Nippe Sealer dropwise, and the oil absorption was measured. The result was 6.8 ml. Furthermore, 20 g of rice grains were mixed with the red iron oxide powder balls, and Nippe Sealer was added dropwise while mixing until the grains formed a single coating. The amount of coating formed was approximately 0.8 ml. Twenty-five grains were immersed in a constant-temperature bath at 25°C, and germination was examined. All germinated by the fifth day. Furthermore, no peeling occurred, even when rubbed vigorously with a finger. Red iron oxide powder has a smaller particle size than black iron oxide powder, so it has a higher oil absorption capacity and the iron powder penetrates into the rice grains more quickly, which is thought to result in a smaller amount of coating being produced.

[0096] (Comparative Example) Next, as a comparative example, we will explain in detail the test results when magnetized rice grains were produced using gypsum (component 1) or PVA (component 2) as the binder instead of water-based paint. (Ingredient 1) Rice grains: iron oxide: gypsum (Component 2) Rice grains: iron oxide: PVA The following commercially available materials were used as rice grains, iron oxide, gypsum, and PVA. Rice: Nourin Koshihikari (R4) Iron oxide: Hanagyoku Co., Ltd. HY-335, Bayferrox318 Plaster of Paris: San-Esu Gypsum Co., Ltd. PVA: Denka B-24YS, B-05S

[0097] The manufacturing method for the above-mentioned component 1, which contains rice grains, iron oxide, and gypsum, is described below. First, 40 g of rice grains and 20 g of iron oxide were extracted, and 2 g, 4 g, and 6 g of gypsum and 2 g and 3 g of PVA (B-24YS) were added separately to the rice grains and iron oxide to create five types of magnetic rice grains. The iron oxide and gypsum, and the iron oxide and PVA, were premixed separately. Next, the rice grains were sprayed with water to moisten them, and the premix was added and mixed. Water was added little by little while mixing. The gypsum hardens in about 15 minutes, so quick processing was required.

[0098] The manufacturing method for the above-mentioned component 2, which contains rice grains, iron oxide, and PVA, is described below. First, magnetic rice grains were prepared in the same manner as component 1 by adding PVA (B-24YS: degree of polymerization approximately 2500, B-05S: degree of polymerization approximately 500) to 50 g of rice grains and 15 g of iron oxide in weight ratios of 3%, 4%, and 5% relative to the iron oxide.

[0099] 20 grains were taken from each of the magnetized rice grains and placed in a wire mesh container underwater (19 + The seeds were soaked in water (0.2°C) and observed for peeling of the coating containing iron oxide. As a result, germination began on the second day after soaking, and all samples germinated by the fourth day. Peeling began immediately after soaking, and when the seeds were removed from the water on the sixth day and touched with the fingers, the coating containing iron oxide peeled off easily.

[0100] As explained above, it was found that the magnetized rice produced using component 1 containing gypsum and component 2 containing PVA had problems such as peeling in water after soaking.

[0101] Example 3 Next, an example of a method for producing magnetized rice grains, which includes a chemical coating step of coating the surface of the magnetized rice grains with chemicals such as agricultural chemicals, will be described in detail.

[0102] Magnetic rice grains are prepared by coating the surface with iron oxide powder using a water-based paint containing an oleophilic resin as a binder. The surface of this magnetized rice grain can be further coated with a water-soluble resin containing the pesticide by mixing iron oxide powder, water-soluble resin, and pesticide. When this magnetized rice grain, which has a double-layer coating structure consisting of an oleophilic resin layer and a hydrophilic resin layer, is immersed in water, the hydrophilic surface coating begins to dissolve first, followed by the pesticide. Since it takes a certain amount of time for the hydrophilic resin in the surface layer to completely dissolve, the pesticide concentration can be maintained near the rice grain for a certain period of time, which can lead to a herbicidal effect. In this embodiment, for example, polyvinyl alcohol resin (PVA resin) can be used as the water-soluble resin.

[0103] To produce magnetically coated rice grains, magnetic rice grains are first prepared by applying iron oxide powder to the surface using an acrylic, water-based paint containing a lipophilic resin, "Nippon Primer Sealer." In this example, 40 g of rice grains and 20 g of iron oxide powder were mixed, and then 4.1 ml of Nippon Primer Sealer was added and mixed to produce 60 g of magnetic rice grains. Next, the iron oxide powder, PVA resin, and chemicals were placed in separate containers and mixed with the magnetized rice at once. A water-soluble pesticide can be used as the mixed chemicals. Examples of the chemicals include pesticides such as fungicides, insecticides, and herbicides used to control pests that harm agricultural crops, as well as growth promoters, germination inhibitors, and other chemicals used to promote or inhibit the growth of agricultural crops. In this example, Kaneyonol PVA (8% PVA content) manufactured by Kaneyo Soap Co., Ltd. was used as the PVA. Two types of herbicide were used: a paddy rice herbicide flowable manufactured by Sumitomo Agro Manufacturing Co., Ltd. (ingredients: imazosulfuron, pyraclonil, benzobicyclon, emulsifier, water (90%)) and a herbicide (Clincher EW) manufactured by Dow AgroSciences Co., Ltd. (ingredients: cyhalofop butyl emulsion). The amount of herbicide added was calculated based on the amount of rice grains contained in the magnetic rice grains. Specifically, 2.5 ml of the herbicide manufactured by Sumitomo Agro Manufacturing Co., Ltd. was added, and 0.5 ml of the herbicide manufactured by Dow AgroSciences Co., Ltd. was added. The magnetic rice grains were then dried at room temperature for, for example, three days, resulting in the formation of magnetic rice grains coated with a PVA film containing the herbicide. In addition, since the amount of pesticides that can be used per unit area is usually limited, it is natural that the concentration of the PVA solution, the amount of pesticide mixed in, solubility, handling of hazardous materials, etc. must be taken into consideration, and it goes without saying that in this embodiment as well, the concentration of the mixed pesticide, etc. must be used within a range that is safe for handling, etc.

[0104] In this example, when using a herbicide (a flowable herbicide for paddy rice) manufactured by Sumitomo Agro Manufacturing Co., Ltd., 12 g of iron oxide powder, 0.9 g of PVA resin, and 2.5 ml of the herbicide manufactured by Sumitomo Agro Manufacturing Co., Ltd. were placed in separate containers for 30 g of magnetic rice grains and mixed together. When using Dow AgroSciences' herbicide (Clincher EW), 6g of iron oxide powder, 0.9g of PVA resin, and 0.5ml of Dow AgroSciences' herbicide (Clincher EW) were placed in separate containers for 30g of magnetic rice grains and mixed together. The mixture was then dried at room temperature for three days to produce magnetic rice grains coated with the drug.

[0105] Twenty-five grains of each type of magnetically coated rice produced using the above method were soaked in a water tank at 21.2°C, and the elution of the PVA coating on the surface and the germination of the magnetic rice were observed. The test results are shown below. In the table, "peeling" indicates the percentage of PVA eluted.

[0106] [Table 7]

[0107] When using the herbicide manufactured by Sumitomo Agro Manufacturing Co., Ltd., the amount of iron oxide powder mixed in with the PVA was large, so the peeling appeared as slightly larger solid pieces that turned into a muddy substance. On the other hand, the herbicide manufactured by Dow AgroSciences Co., Ltd. (Clincher EW) dissolved in a muddy state from the start. Referring to Table 7 above, for herbicides manufactured by Sumitomo Agro Manufacturing Co., Ltd. and Dow AgroSciences, Inc., leaching began about three to four days after soaking, and was completely leached after five days. Furthermore, germination from the magnetic rice grains was confirmed about four days after soaking. This confirmed the effectiveness of the herbicide-coated magnetic rice grains.

[0108] By using magnetite as the iron oxide, it is possible to produce magnetic rice grains. Next, a sowing method using the magnetic rice grains produced by the above-mentioned method will be described below.

[0109] (Seeding method using a sowing machine with magnets) The relationship between magnetized rice grains and magnetic force was investigated. 20g of rice grains and 2g, 4g, 6g, and 10g of iron oxide powder were weighed out, and magnetized rice grains were created using Nippe Primer Sealer (acrylic) water-based paint as a resin. When the magnetized rice grains, which had been dried at room temperature for three days, were dropped into water from a height of approximately 15cm, none of the samples floated; they immediately sank. After sinking, air bubbles were visible on the surface of the grains, but none rose to the surface. However, if the magnetized rice grains were gently submerged underwater, they would float. They would sink if gently pressed with a finger to remove the air bubbles. The adhesive strength of the magnetized rice grains in their dry state was investigated. The test method used a neodymium magnet with a specified adhesive strength. The magnet was placed approximately 1cm above the surface of the magnetized rice grains, and the number of grains that were attracted was counted three times, and the average value was calculated. This was a static test, not a dynamic one in which the magnet is moved. As shown below, a fairly low suction force was found to be sufficient to move 4-6 grains of rice.

[0110] [Table 8]

[0111] The above describes the production of magnetically magnetized rice grains by attaching iron oxide powder to the surface of rice grains. However, this method is not limited to rice grains, and can be applied to seeds of sesame, adzuki beans, daifuku mochi, peanuts, and other varieties. For example, seeds other than rice grains were produced using peanuts and sesame seeds, and the strength of the coating containing iron oxide powder attached to the surface of the seeds was examined. 29 g (23 peanuts) and 5 g of iron oxide powder were mixed, and then 1.1 ml of Nippon Paint Primer Sealer was added. However, the coating was not satisfactory. Therefore, approximately 0.5 ml of water was added and mixed, resulting in a good coating. After drying at room temperature for three days, the mixture was rubbed vigorously with a hand, but no peeling or other problems were observed. In addition, after mixing 15g of sesame seeds and 8g of iron oxide powder, 4ml of Nippe primer sealer was added and mixed, and after drying at room temperature for 3 days, the coating was rubbed hard with hands, but there was no peeling of the coating. When both types were mixed, they did not form a lump, but rather independent individual grains were obtained.

[0112] While the principles of the present invention have been illustrated and described in preferred embodiments, it will be recognized by those skilled in the art that the present invention can be modified in arrangement and detail without departing from such principles. The present invention is not limited to the particular constructions disclosed herein. We therefore claim all modifications and variations that come within the scope and spirit of the following claims.

Claims

1. A method for producing seeds having iron oxide attached to the surface of plant seeds, comprising: a preparation step of preparing a water-based paint containing the plant seeds, the iron oxide in powder or granules, and a lipophilic resin that functions as a binder; a coating amount determination step for determining a mixed coating amount of the aqueous paint required to adhere the iron oxide to the plant seed; a mixing step of mixing the plant seeds, the iron oxide, and the aqueous paint in an amount that will produce the mixed coating.

2. The seed manufacturing method described in claim 1, characterized in that the coating production amount determination process includes an iron oxide oil absorption determination process for determining an iron oxide oil absorption amount, which is the amount of water-based paint required to fill the voids between the iron oxide with the water-based paint, and a seed coating production amount determination process for determining a seed coating production amount, which is the amount of water-based paint required to adhere the iron oxide powder to the surface of the plant seed when the iron oxide powder in a state filled with the water-based paint is mixed with the plant seed.

3. 2. The method for producing seeds according to claim 1, characterized in that in the step of determining the iron oxide oil absorption, the iron oxide oil absorption is determined as the amount of aqueous paint when the aqueous paint is mixed with the iron oxide and supplied until the iron oxide forms a lump-like shape.

4. The seed manufacturing method described in claim 1, characterized in that in the seed coating production amount determination step, the seed coating production amount is determined as the amount when the iron oxide is mixed with the aqueous paint, the iron oxide becomes clump-shaped, the plant seeds are mixed with the iron oxide, and then the aqueous paint is further mixed in, and the plant seeds become individual grains with the iron oxide attached to their surface.

5. In the mixing step, a first mixing step of mixing the plant seeds and the iron oxide; 2. The method for producing seeds according to claim 1, further comprising a second mixing step of gradually mixing the water-based paint in an amount sufficient to produce the mixed coating, after the first mixing step.

6. 2. The method for producing seeds according to claim 1, wherein the water-based paint contains at least one resin selected from the group consisting of a polyacrylic resin, a polyurethane resin, and a polyvinyl acetate resin.

7. 2. The seed manufacturing method according to claim 1, wherein the iron oxide contains at least one of hematite, goethite, and magnetite.

8. 2. The seed manufacturing method according to claim 1, further comprising the step of mixing iron oxide powder, a chemical agent, and a water-soluble polyvinyl alcohol resin after the mixing step, and adhering the chemical agent to the surface of the plant seeds.

9. The method for producing seeds described in claim 8, characterized in that the chemicals include herbicides, fungicides and insecticides used to control pests that harm agricultural crops, or growth promoters and germination inhibitors used to promote or suppress the growth of agricultural crops, etc.

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