KR102329011B1 - Coating material for rice seeds and coated rice seeds - Google Patents

Abstract

(Project) To provide a coating material for rice seeds that does not have a problem of lowering the germination rate due to heat or the like and is not easily peeled off in water.
(Solution) Rice seeds are coated with a coating material containing iron oxide and alpha starch having a swelling degree of 10 to 48 ml/g at 20°C of a 2% aqueous suspension.

Description

Coating materials for rice seeds and coated rice seeds {COATING MATERIAL FOR RICE SEEDS AND COATED RICE SEEDS}

The present invention relates to a coating material for rice seeds and to coated rice seeds.

Conventionally, in a cultivation method of directly sowing rice seeds into a paddy field, so-called direct sowing cultivation, a technique for suppressing floating of rice seeds by coating the rice seeds with reduced iron and making them heavy is known (see, for example, non-patent document 1). ). Moreover, in order to prevent the iron powder coated with rice seed from peeling in water, the technique of adhering and solidifying iron content to the rice seed surface by accelerating|stimulating the oxidation reaction of metallic iron powder is known (refer patent document 1). Since these conventional iron coating technologies use reduced iron that is oxidized and solidified, it is necessary to dissipate the heat generated during oxidation, and the management of the coated rice seeds is complicated, and the management of the coated rice seeds is difficult. When insufficient, there was a problem that the germination rate was lowered.

As a method of solving such a problem, for example, a technique of coating rice seeds using carboxymethyl cellulose (CMC) or polyvinyl alcohol having a high saponification degree together with iron powder is known (Non-Patent Document 2, Patent Document 2) Reference). However, the technology still has room for improvement in terms of suppressing peeling of the coating material in water.

Japanese Laid-Open Patent Publication No. 2005-192458 Japanese Patent Laid-Open No. 2013-146266

Minoru Yamauchi, 「Iron Coated Fresh Water Direct Sowing Manual 2010」, Kinki Chugoku Shikoku Agricultural Research Center, an independent administrative agency, agricultural and food industry technology research institute, March 2010 Masami Furuhata, "Effect of different laver components in iron oxide-coated seeds on germination and seedling of freshwater direct-sown water rice," Hokuriku Crop Society Proceedings 43, 15-18 (2008)

An object of the present invention is to provide a coating material for rice seeds that does not have a problem of lowering the germination rate due to heat or the like and is not easily peeled off in water. Moreover, it makes it a subject to provide the coated rice seed which has a high germination rate and the material which coats the rice seed does not peel easily in water.

As a result of the present inventors examining in order to find out the coating material for rice seeds and coated rice seed which are consistent with such a purpose, in the coating of rice seeds with iron oxide, the swelling degree at 20 degreeC of a 2% aqueous suspension is 10- It has been found that the above problems can be solved by using 48 ml/g of alpha starch (hereinafter, referred to as the present alpha starch).

That is, the present invention is as follows.

[1] A coating material for rice seeds comprising iron oxide and alpha starch having a swelling degree of 10 to 48 ml/g of a 2% aqueous suspension at 20°C.

[2] The coating material for rice seeds according to [1], which contains an agrochemical active ingredient.

[3] A coated rice seed in which the rice seed is coated with a coating material containing iron oxide and alpha starch having a swelling degree of 10 to 48 ml/g at 20°C of a 2% aqueous suspension.

[4] A coated rice seed in which the rice seed is coated with a coating material containing iron oxide, alpha starch having a swelling degree of 10 to 48 ml/g at 20°C of a 2% aqueous suspension, and an agrochemical active ingredient.

[5] A rice cultivation method in which the coated rice seed according to [3] or [4] is directly sown in a paddy field.

ADVANTAGE OF THE INVENTION According to this invention, there is no problem of the fall of the germination rate by heat_generation|fever etc., and it can provide the coating material for rice seeds which do not peel easily in water. In addition, it is possible to provide a coated rice seed having a high germination rate and the material for which the rice seed is coated is not easily peeled off in water.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing for demonstrating the simple seed coating machine used for coating of a rice seed in an Example.
It is explanatory drawing which shows the state of "absence of peeling presence or absence" described in Table 3. FIG.
It is explanatory drawing which shows the state of "existence" of peeling described in Table 3.

According to the present invention it is iron oxide, meaning that it contains iron oxide as a main component represented by a Fe ₂ O _3. Iron oxide in the present invention, a more than 70% content of α-Fe ₂ O ₃ of iron oxide of (% by weight on the iron oxide) known as hematite is preferred. In the present invention, _{the content of α-Fe 2} O ₃ is determined by XRD (X-ray diffraction method). In addition, it is preferable to use iron oxide having a particle size distribution in which particles having a size of 150 µm or more are 40% or less. In the present invention, the particle size distribution of iron oxide means a particle size distribution measured by a sieve method, and that particles having a size of 150 μm or more have a particle size distribution of 40% or less means that the scale size is 150 μm of the remaining amount on a sieve It shows that the weight ratio with respect to the whole is 40 % or less. The particle size distribution of iron oxide is determined by placing 10 g of iron oxide on a sieve having a scale size of 150 µm (standard sieve specified in JIS Z8801-1982) and shaking it with a sieving device such as a low-tap shaker, then the weight of the iron oxide remaining on the sieve can be measured and calculated by the following formula.

Residual amount on sieve (%) = Weight of iron oxide remaining on the sieve (g) / Weight of iron oxide on the first sieve (g) x 100

The coating material for rice seeds of the present invention (hereinafter, referred to as this coating material) contains iron oxide, and the content thereof is usually 84.0 to 99.5% by weight, preferably 93.0 to 99.4 with respect to 100% by weight of the present coating material. % by weight, more preferably in the range of 93.0 to 99.0% by weight.

Alpha starch in the present invention is also called gelatinized starch or gelatinized starch, and means starch having a degree of pregelatinization of 90% or more. In the present invention, the degree of pregelatinization of alpha starch is obtained by an analysis method in accordance with Customs Central Analysis Law No. 51. The analysis method according to Customs Central Analysis Report No. 51 is as follows.

1. Adjustment of reagents

Phosphoric acid-citrate buffer solution (pH = 4.0-5.0)

15 ml of 1 M phosphoric acid and 17 ml of 0.1 M citric acid are added to 1.5 ml of 10 M sodium hydroxide aqueous solution, and it adjusts to pH=4.0-5.0.

Glucoamylase solution

Glucoamylase (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved with deionized water so that the titer was about 15 units per ml.

No. (除) protein A solution

ZnSO ₄ 7H ₂ O aqueous solution (1.8 % (W/V))

Second (除) protein B solution

Ba(OH) ₂ 8H ₂ O aqueous solution (2.0 % (W/V))

Glycerin standard solution

1.0 g of glycerin is fixedly used in 25 ml of deionized water.

2. Preparation of sample solution

A uniform suspension (1.25 g of starch sample/100 ml of deionized water) is prepared, 4.0 ml of the suspension is placed in two 50 ml Erlenmeyer flasks, and 3.35 ml of a phosphate-citrate buffer solution is added to each to make solution I. To the other, 0.15 ml of a 10 M aqueous sodium hydroxide solution is added, heated at 37° C. for 30 minutes to completely swell and disintegrate the starch particles, and then 1.5 ml of 1 M phosphoric acid and 1.7 ml of 0.1 M citric acid are added, and solution II do it with The two solutions were placed in a 37°C thermostat, and after the temperature was stabilized, 2.0 ml of a glucoamylase solution was added to each solution, and the starch and glucoamylase in each solution were reacted for 120 minutes while shaking. Thereafter, the enzyme is inactivated in the boiling bath, and 5.0 ml of protein A solution, 5.0 ml of solution B, and 1.0 ml of a standard glycerin solution are added to each solution. Each of the obtained solutions is transferred to a 50 ml centrifuge tube, and centrifugation is performed at 4000 rpm for 5 minutes. The supernatant is passed through a membrane filter (0.45 µm), and the obtained solution is used as a test solution for glucose quantification (liquid Ia and solution IIa).

3. Quantification of Glucose

The glucose weight of the liquid Ia and the liquid IIa was quantified with a glucose CII-test Wako (manufactured by Wako Pure Chemical Industries, Ltd.) which is a glucose kit.

4. Calculation of degree of alpha

The degree of pregelatinization is calculated by the following formula as the ratio of the glucose weight (g) of the liquid Ia to the glucose weight (g) of the liquid IIa as a reference.

Degree of gelatinization (%) = Weight of glucose in liquid Ia (g) / Weight of glucose in liquid IIa (g) x 100

In the present invention, commercially available alpha starch can be used, and examples of such commercially available alpha starch include Amirox No. can

As this alpha starch, powdery alpha starch is preferable, and the particle diameter is 1000 micrometers or less normally, Preferably it is 800 micrometers or less. In the present invention, the particle size of alpha starch is a particle size measured by a laser diffraction/scattering type particle size distribution analyzer, and refers to a particle size that is 100% of the cumulative frequency in the volume-based frequency distribution. As a laser diffraction/scattering type particle size distribution measuring apparatus, MASTERSIZER2000 (made by MALVERN) is mentioned, for example, The method of disperse|distributing particle|grains in the air and measuring using this apparatus, it can obtain|require by so-called dry measurement.

The swelling degree of this alpha starch means the swelling degree measured by the volumetric method. The swelling degree at 20 degreeC of a 2% aqueous suspension is the swelling degree of alpha starch calculated|required from the suspension which suspended 2% of alpha starch in water at 20 degreeC. The specific measuring method of swelling degree is described below. First, 2.0 g of a sample is added little by little to a 200 ml beaker containing 100 ml of ion-exchange water, and after injecting|throwing-in the whole quantity, it stirs at room temperature for 5 minutes. Thereafter, the obtained solution was transferred to a measuring cylinder equipped with a 100 ml ball stopper, the solution was capped and left still in a constant temperature water bath at 20° C. for 24 hours, and the apparent volume of the sample swollen in the container was measured. By reading, the degree of swelling (ml/g) is calculated. The swelling degree of the present alpha starch is in the range of 10 to 48 ml/g, preferably 12 to 46 ml/g.

This coating material contains this alpha starch, and the content is 0.5 to 6.0 weight% normally with respect to 100 weight% of this coating material, Preferably it is the range of 1.0-4.0 weight%. In addition, in this coating material, the weight ratio of iron oxide and this alpha starch is 200:1-12:1 normally, Preferably it is the range of 100:1-25:1.

In the present invention, an agrochemical active ingredient can also be used. Examples of such agrochemical active ingredients include insecticidal active ingredients, bactericidal active ingredients, herbicidal active ingredients, and plant growth regulating active ingredients.

Such pesticidal active ingredients include, for example, clothianidin, imidacloprid, and thiamethoxam.

Examples of such bactericidal active ingredients include isotianil and furametpyr.

Examples of such herbicidal active ingredients include imazosulfuron and bromobutide.

Such an active ingredient for regulating plant growth includes, for example, uniconazole P.

As the agrochemical active ingredient contained in the present coating material, a powdery agrochemical active ingredient is preferable, and the particle size is usually 200 µm or less, preferably 100 µm or less. As such an agrochemical active ingredient, if necessary, a pulverized product may be used in which the agrochemical active ingredient mixed with a solid carrier such as clay is pulverized by a pulverizer such as a dry pulverizer to have the particle size or smaller. In the present invention, the particle size of the agrochemical active ingredient is a particle size measured by a laser diffraction/scattering type particle size distribution analyzer, and refers to a particle size that is 100% of the cumulative frequency in the volume-based frequency distribution. In addition, when the agrochemical active ingredient is a mixture with a solid carrier, it means the particle size of the mixture. As a laser diffraction/scattering type particle size distribution analyzer, for example, LA-950V2 (manufactured by Horiba Corporation) is mentioned, and a method of measuring by dispersing particles of an agrochemical active ingredient in water using the apparatus, so-called wet measurement can be obtained by

The content of the agrochemical active ingredient in the present coating material is usually 0 to 10.0% by weight, preferably 0.01 to 10.0% by weight, more preferably 0.5 to 5.5% by weight based on 100% by weight of the present coating material.

This coating material can be obtained by mixing iron oxide, this alpha starch and, if necessary, an agrochemical active ingredient.

The coated rice seed of the present invention (hereinafter, referred to as the present coated rice seed) is a rice seed coated with a coating material containing iron oxide and the present alpha starch, and is rice with the present coating material obtained as described above. It can be obtained by coating seeds or by coating rice seeds with the present alpha starch gelatinization solution and a mixture containing iron oxide and, if necessary, an agrochemical active ingredient. In the manufacturing method of this coated rice seed, the weight ratio of the dried rice seed and iron oxide is 4:1-1:4 normally, Preferably the rice seed is coated so that it may become the range of 2:1-1:2. . This coated rice seed can be manufactured more specifically as follows.

Put the dried rice seeds in a rice seed bag and soak them. In order to obtain a coated rice seed with a high germination rate, it is preferable to make water temperature into 15-20 degreeC, and to immerse for 3 to 4 days. Thereafter, the rice seeds pulled out of water are allowed to stand still, or excess moisture on the surface is removed by dewatering with a dehydrator, and then placed in the drum of a manual or automatic coating machine commonly used for seed coating and rotating the rice seeds. Then, about 1/4 to 1/3 of the total amount of the coating material used is applied to the rice seeds rotating in the drum, and water is sprayed on the mixture of the coating material and the rice seeds by mist spraying. By doing so, this coating material is attached to the surface of the rice seed. However, when the coating material is adhered to the inner wall of the drum, the above operation is performed while scraping it using a scraper or dustpan. After repeating this operation 2 to 3 times, the entire amount of this coating material is coated on the rice seeds. The total amount of water sprayed at the time of coating is appropriately adjusted according to the moisture content of the rice seeds, but it is preferably in the range of 1/10 to 1/3 by weight of the iron oxide.

When rice seeds are coated using a mixture containing iron oxide and agrochemical active ingredient (hereinafter referred to as mixture I) and this alpha starch gelatinization solution, in the above method, mixture I is used instead of this coating material and replace part or all of the sprayed water with this alpha starch gelatinization solution. In this case, since the present alpha starch is used after swelling or dissolving in water, the particle size distribution is not particularly limited. This alpha-starch gelatinization liquid can be obtained by mixing water and this alpha-starch and stirring. In the preparation of the present alpha starch gelatinization solution, the weight ratio of iron oxide and the present alpha starch in the present coated rice seed is usually 200:1 to 10:1, preferably 100:1 to 25:1. The amount of alpha starch is determined, and some or all of the water sprayed at the time of coating is used so that the concentration of the present alpha starch is usually adjusted to be in the range of 0.5 to 50% by weight. If the amount of water sprayed during coating becomes excessive, the coated rice seeds will adhere to each other. , it is preferable to adjust the amount of water used in the preparation of the present alpha starch gelatinization solution so that additional water can be sprayed while checking the state of the coating.

The amount of the agrochemical active ingredient in the mixture I is determined so that the weight ratio of the dried rice seed to the agrochemical active ingredient is usually in the range of 20000:1 to 20:1, preferably 250:1 to 30:1.

After the coating operation is completed, the rice seeds taken out from the drum of the coating machine are thinly spread on a flat mat, a plastic sheet, or a seedling bed, etc. and dried to obtain the main coated rice seeds.

The rice cultivation method (henceforth this cultivation method) of this invention is implemented by sowing this coated rice seed directly into a paddy field. In the present invention, the rice paddy refers to either a freshwater paddy field or a dripped paddy field. Specifically, seeding is performed according to the method described in Non-Patent Document 1. In that case, direct sowing machines for iron coatings, such as Tetsumakichan (made by Kubota Co., Ltd.), can be used. After sowing, good cultivation is achieved by maintaining the normal cultivation conditions.

In this cultivation method, you may apply an agricultural chemical and a fertilizer before sowing, simultaneously with sowing, or after sowing. Examples of such pesticides include fungicides, pesticides and herbicides.

[Example]

Next, the present invention will be described in more detail by way of Examples.

First, the compounding example of a coating material is shown. The degree of precipitation of alpha starch was determined by an analysis method in accordance with Customs Central Analysis Report No. 51 described in this specification.

Formulation Example 1

Iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) 10 g, alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, gelatinization degree 98%, Japanese corn starch Co., Ltd.) 0.1 g was mixed, and the coating material 1 for rice seeds of this invention was obtained.

Combination Example 2

Iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) 20 g, alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, gelatinization degree 98%, Japanese corn starch Co., Ltd.) 0.2 g was mixed, and the coating material 2 for rice seeds of this invention was obtained.

Formulation example 3

40 g of iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 μm or more 18.0%) 40 g, alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, gelatinization degree 98%, Japanese corn starch Co., Ltd.) 1.6 g was mixed, and the coating material 3 for rice seeds of this invention was obtained.

Formulation example 4

Instead of alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, manufactured by Nippon Corn Starch Co., Ltd.), alpha starch (swelling degree 18.5 ml/g, trade name; corn alpha Y, gelatinization degree 96%, Sanwa Starch Kogyo) Except having used Co., Ltd. product), it carried out similarly to the formulation example 1, and obtained the coating material 4 for rice seeds of this invention.

Combination Example 5

70.0 parts by weight of (E)-1-(2-chloro-1,3-thiazol-5-ylmethyl)-3-methyl-2-nitroguanidine (generic name: clothianidin) and 30.0 parts by weight of pyrophyllite ( Brand name; After mixing Shokozan Clay S, the Shokozan Mining Co., Ltd. make), it grind|pulverized with the centrifugal grinder, and the powdery pesticide A was obtained. The particle diameter of the powdery pesticide A calculated|required by wet measurement using LA-950V2 (made by Horiba Corporation) was 68.0 micrometers.

Iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) 10 g, alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, gelatinization degree 98%, Japanese corn starch Co., Ltd.) 0.1 g and powdery agricultural chemical A 0.086 g were mixed, and the coating material 5 for rice seeds of this invention was obtained.

Combination Example 6

70.0 parts by weight of 3,4-dichloro-N-(2-cyanophenyl)isothiazole-5-carboxamide (general name: isothianil) and 30.0 parts by weight of pyrophyllite (trade name; Shokozan Clay S, Shokozan Co., Ltd.) Mining company manufacture), and then pulverized with a centrifugal grinder to obtain a powdery pesticide B. The particle size of the powdery agrochemical B calculated|required by wet measurement using MASTERSIZER2000 (made by MALVERN) was 52.4 micrometers.

Iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) 10 g, alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, gelatinization degree 98%, Japanese corn starch Co., Ltd.) 0.1 g and powdery pesticide B 0.184 g were mixed, and the coating material 6 for rice seeds of this invention was obtained.

Combination Example 7

45.5 parts by weight of (RS)-5-chloro-N-(1,3-dihydro-1,1,3-trimethylisobenzofuran-4-yl)-1,3-dimethylpyrazole-4-carboxamide (General name: Furametpyr), 45.5 parts by weight of bentonite (trade name; Bentonite Hodaka, manufactured by Hojun Co., Ltd.) and 9.0 parts by weight of amorphous silicon dioxide (trade name: Tokusil GUN, manufactured by Oriental Silica) After mixing, a centrifugal grinder It grind|pulverized and obtained the powdery pesticide C. The particle size of the powdery pesticide C calculated|required by wet measurement using MASTERSIZER2000 (made by MALVERN) was 26.3 micrometers.

Iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) 10 g, alpha starch (swelling degree 15.5 ml/g, trade name; Amirox No. 1A, gelatinization degree 98%, Japanese corn starch Co., Ltd.) 0.1 g and powdery pesticide C 0.554 g were mixed, and the coating material 7 for rice seeds of this invention was obtained.

Comparative formulation example 1

10 g of iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) and 0.1 g of dextrin (trade name; Amicol No. 1, manufactured by Nippon Starch Chemical Co., Ltd.) were mixed and rice for comparison The coating material 1 for seeds was obtained.

Comparative formulation example 2

A comparison was made in the same manner as in Comparative Formulation Example 1 except that dextrin (trade name; Red Ball Dextrin ND-S, manufactured by Nippon Starch Chemical Co., Ltd.) was used instead of dextrin (trade name; Amicol No. 1, manufactured by Nippon Starch Chemical Co., Ltd.) The coating material 2 for rice seeds of dragon was obtained.

Comparative formulation example 3

10 g of iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%), 0.1 g of sodium carboxymethylcellulose (trade name; Cellogen 3H, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and 0.086 g of powdery pesticide A was mixed to obtain a comparative coating material 3 for rice seeds.

Comparative formulation example 4

Polyvinyl alcohol (degree of polymerization; 1700, degree of saponification; 98.0 to 99.0 mol%, trade name; Kuraray Poval PVA117S, manufactured by Kuraray Co., Ltd.) was used instead of dextrin (trade name; Amicol No. 1, manufactured by Nippon Starch Chemical Co., Ltd.) Except that, it carried out similarly to the comparative compounding example 1, and obtained the coating material 4 for rice seeds for a comparison.

Comparative formulation example 5

7 g of iron oxide (α-Fe ₂ O ₃ content 78%, particle size distribution; 150 µm or more 18.0%) and 3 g of iron oxide (trade name; DAE1K, manufactured by DOWA IP Creation Co., Ltd.) are mixed, and comparative rice seed coating material 5 got

Comparative formulation example 6

10 g of iron powder (trade name; DAE1K, manufactured by DOWA IP Creation Co., Ltd.) and 1 g of baked gypsum (trade name; KTS-1, manufactured by Yoshino Gypsum Sales Co., Ltd.) were mixed to obtain a comparative coating material 6 for rice seeds.

Next, the manufacturing example of a coated rice seed is shown.

Preparation Example 1

First, a simple seed coating machine for coating a small amount of rice seeds was manufactured. As shown in Fig. 1, a polyethylene cup 2 having a capacity of 200 ml is attached to the end of the shaft 1, and it is inserted into the drive shaft of the stirrer 3 (three-one motor, manufactured by Shinto Science Co., Ltd.), and the elevation angle is The simple seed coating machine was produced by attaching to the stand 4 by tilting the stirrer 3 so that it might become 45 degrees.

Water was poured into a polyethylene cup with a capacity of 200 ml prepared separately, 20 g of dried rice seeds (Hinohikari) were put there, and immersed at room temperature (10°C) for 10 minutes. The rice seeds were pulled up from the polyethylene cup, and excess moisture on the surface was sucked up with Kimwipe (registered trademark), and then the rice seeds were put into the polyethylene cup attached to the prepared simple seed coating machine. The simple seed coating machine is rotated in the range of 130 to 140 rpm with the number of rotations of the stirrer, and while water is sprayed on the surface of the rice seeds by mist spray, about 1/4 of 10.1 g of the coating material for rice seeds of the present invention is put in. and coated on rice seeds. When the fluidity|liquidity of a rice seed was bad, it rotated using the spatula. Then, all the coating material 1 for rice seeds of this invention were coated on the rice seed by repeating the same operation 3 times. The total amount of water used for coating was 1.4 g. The coated rice seed 1 of this invention was obtained by spreading and drying overnight so that the rice seed obtained on the stainless steel vat might not overlap.

Production Examples 2 to 7

Operation similar to manufacture example 1 was performed using the coating materials 2-7 for rice seeds of this invention, respectively, and the coating rice seeds 2-7 of this invention were obtained, respectively. In addition, Table 1 shows the input amount of the coating material in each production example and the total amount of water used for coating.

Comparative Preparation Examples 1 to 4

Operation similar to manufacture example 1 was performed using the coating materials 1-4 for rice seeds for a comparison, respectively, respectively, and the coating rice seeds 1-4 for a comparison were obtained, respectively. In addition, Table 2 shows the input amount of the coating material and the total amount of water used for coating in each comparative production example.

Comparative Preparation Example 5

Water was poured into a polyethylene cup with a capacity of 200 ml, and 20 g of dried rice seeds (Hinohikari) were placed there, followed by immersion at room temperature (10°C) for 10 minutes. The rice seeds were pulled up from the polyethylene cup, and excess moisture on the surface was sucked up with Kimwipe (registered trademark), and then the rice seeds were put into a polyethylene cup attached to a simple seed coating machine. In addition, the simple seed coating machine used the thing used by manufacture example 1. The simple seed coating machine is rotated in the range of 130 to 140 rpm with the rotation speed of the stirrer, and while water is sprayed on the rice seed surface by mist spray, about 1/4 of 10 g of the comparative rice seed coating material 5 is added and coated on rice seeds. When the fluidity|liquidity of a rice seed was bad, it rotated using the spatula. Then, all the coating materials 5 for rice seeds were coated on the seed by repeating the same operation 3 times. The total amount of water used for coating was 1.2 g. The rice seeds obtained on a stainless steel batt were spread out so that they did not overlap and dried overnight. After the next day, in order to accelerate the oxidation of iron, operation of spraying water on the rice seed surface 3 times a day was performed for 2 days, and the coated rice seed 5 for a comparison was obtained by drying after that.

Comparative Preparation Example 6

Water was poured into a polyethylene cup with a capacity of 200 ml, and 20 g of dried rice seeds (Hinohikari) were put there, and immersed at room temperature (10°C) for 10 minutes. The rice seeds were pulled up from the polyethylene cup, and excess moisture on the surface was sucked up with Kimwipe (registered trademark), and then the rice seeds were put into the polyethylene cup attached to the prepared simple seed coating machine. In addition, the simple seed coating machine used the thing used by manufacture example 1. The simple seed coating machine is rotated in the range of 130 to 140 rpm with the number of rotations of the stirrer, and while water is sprayed on the surface of the rice seeds by mist spray, about 1/4 of the coating material 6 for rice seeds 6 11 g is added to the rice seeds coated on. When the fluidity|liquidity of a rice seed was bad, it rotated using the spatula. Then, all the coating materials 6 for rice seeds were coated on the seed by repeating the same operation 3 times. The total amount of water used for coating was 3.5 g. Next, 0.5 g of baked gypsum was added and adhered to the surface of the rice seeds coated with the comparative coating material 6 for rice seeds. The rice seeds obtained on the stainless steel batt were spread out so that they did not overlap and dried overnight. After the next day, in order to accelerate the oxidation of iron, operation of spraying water on the rice seed surface 3 times a day was performed for 2 days, and the coated rice seed 6 for a comparison was obtained by drying after that.

Next, a test example is shown.

Test Example 1

10 coated rice seeds obtained in Production Example 1 were put into a glass Petri dish containing 50 ml of 3 degree hard water, and the presence or absence of peeling of the coating was visually observed after 30 minutes. The same test was done also to the coated rice seed obtained by manufacture examples 2-7 and comparative manufacture examples 1-5.

A result is shown in Table 3.

With or without peeling Preparation Example 1 does not exist Preparation 2 does not exist Preparation 3 does not exist Preparation 4 does not exist Preparation 5 does not exist Preparation 6 does not exist Preparation 7 does not exist Comparative Preparation Example 1 has exist Comparative Preparation Example 2 has exist Comparative Preparation Example 3 has exist Comparative Preparation Example 4 has exist Comparative Preparation Example 5 has exist

Test Example 2

The rotation speed of the ball mill rotating mount was set to 100 rpm. 20 g of the coated rice seed obtained in Preparation Example 1 was put into a 200 ml mayonnaise bottle, placed on a ball mill rotary mount, and rotated for 5 minutes. Thereafter, the sieve was sieved using a sieve having a scale of 1000 µm, and the weight of the peeled product passing through the sieve was measured, and the peeling rate was calculated by the following formula.

Peeling rate (%) = Weight of peeled material (g) / Weight of attachment contained in 20 g of coated rice seeds before test (g) x 100

The same test was implemented also to the coated rice seed obtained by manufacture examples 2, 4-7 and comparative manufacture examples 1, 2, 4, and 5.

However, the deposits in the above formula are used in the above production examples or comparative production examples and refer to all of the solid substances adhering to the rice seeds, specifically, iron oxide, the present alpha starch, and an agrochemical active ingredient.

A result is shown in Table 4.

Test Example 3

Gauze moistened with water was laid on a plastic Petri dish, and 50 coated rice seeds obtained in Preparation Example 1 were placed thereon. The Petri dish was covered with a lid, and it was left still in a 17 degreeC thermostat, the presence or absence of germination was investigated 7 days later, and the germination rate was computed with the following formula.

Germination rate (%) = number of germinated seeds/50×100

The same test was conducted using the coated rice seeds obtained in Production Examples 2 to 4 and Comparative Production Example 6. A result is shown in Table 5.

Industrial Applicability

ADVANTAGE OF THE INVENTION According to this invention, there is no problem of the fall of the germination rate by heat_generation|fever etc., and it can provide the coating material for rice seeds which do not peel easily in water. In addition, it is possible to provide a coated rice seed having a high germination rate and the material for which the rice seed is coated is not easily peeled off in water.

1: shaft
2: Cup made of polyethylene
3: agitator
4: Stand

Claims (5)

A coating material for rice seeds comprising iron oxide and alpha starch having a swelling degree of 10 to 48 ml/g at 20°C of a 2% aqueous suspension. The method of claim 1,
Coating material for rice seeds containing agrochemically active ingredients. The coated rice seed in which the rice seed is coated with the coating material containing iron oxide and alpha starch whose swelling degree at 20 degreeC of 2% aqueous suspension is 10-48 ml/g. A coated rice seed, wherein the rice seed is coated with a coating material containing iron oxide, alpha starch having a swelling degree of 10 to 48 ml/g at 20°C of a 2% aqueous suspension, and an agrochemical active ingredient. A rice cultivation method in which the coated rice seed according to claim 3 or 4 is directly sown in a paddy field.

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