JPH0445123B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a powder coating agent for rice seeds for direct sowing in flooded soil. BACKGROUND OF THE INVENTION In recent years, direct sowing in flooded soil, a new method of cultivating paddy rice, is rapidly becoming popular in Japan. This method uses seeds directly instead of transplanting rice seedlings.
Seeds are sown into the soil at a depth of ~1.5 cm, which not only greatly reduces the labor and time required to grow rice seedlings, but also increases yield by 10 to 20% as there is no mechanical damage to the plants during transplanting. be done. In the direct sowing cultivation method in flooded soil, seeds are sown at a depth of 1 to 1.5 cm from the soil surface in a flooded state, so seeds lack oxygen and smooth germination cannot be expected. As a way to overcome this problem,
Japanese Patent Publication No. 47-28751 (method for promoting germination of rice seeds) and Japanese Patent Publication No. 55-22045 (direct sowing method in flooded soil) have already been disclosed. That is, calcium peroxide aids in the germination of rice seeds by utilizing the property of reacting with water in the soil and gradually releasing oxygen. Problems to be Solved by the Invention However, even with seeds treated with powder coating with calcium peroxide, germination and seedling establishment may be poor in poor environmental conditions such as strongly reduced fields or low temperatures after sowing. It is considered a problem that the seeds may not germinate at all. One way to solve these problems is to mix calcium peroxide with 3-hydroxy-5-methylisoxazole (trade name: Tachigaren, manufactured by Sankyo Co., Ltd.) and coat the seeds with the mixture, which is expected to be effective. It has been reported that this can be done [Masami Ogawa et al., Agriculture and Horticulture 48 , 1297-1300 (1973)]. but,
Satisfactory effects may not necessarily be obtained in all environmentally poor paddy fields. Means for Solving the Problem The present inventors have conducted intensive studies to solve this problem, and as a result, have found a specific causal relationship caused by a specific compound, and have completed the present invention. This is a powder coating agent for rice seeds for direct sowing in flooded soil containing calcium and 5-butyl-2-dimethylamino-6-methylpyrimidin-4-ol (trade name of ICI Corporation, Milcarb, hereinafter referred to as Milcarb). Milcarb is a fungicide used only to control powdery mildew on cucumbers, melons, etc., and is not applied to paddy rice. In carrying out the present invention, there is a method in which calcium peroxide and Milcarb are mixed in advance as a dusting agent and then powder coating is applied, and seeds are immersed in a diluted Millcarb solution before dressing, and then calcium peroxide is applied to the seeds. Alternatively, a method such as using a diluted milk carb solution instead of the water used when coating calcium peroxide can be used. Furthermore, if necessary, it can be used in combination with known drugs that are known to reduce or prevent the effects of calcium peroxide, or depending on the purpose, it can be used in combination with a plant growth regulator that has a growth-promoting effect. You can also. The mixing ratio of calcium peroxide and Milcarb is
Depending on the conditions of the paddy fields in which this powder coating is sown, for example, in severely reduced fields, calcium peroxide preparations (paddy coating preparations containing 35% calcium peroxide, Hodogaya Chemical Industry Co., Ltd. trade name: Calper powder, hereinafter referred to as Calper powder) Milcarb formulation (active ingredient: 12.5%)
It is useful to add about 8% of the mill carb (liquid agent containing), but it is usually 0.2% to 8%, more preferably 0.5% to 3%. Since the amount used per 10 ares of Calper powder is about 3 to 4 kg, adding 2% of Milcarb to Calper powder is calculated to be only about 10 g of active ingredient per 10 ares. Effects of the Present Invention It is surprising that such a small amount of mill carb can bring about a remarkable improvement in the rate of germination and seedling establishment in paddy fields with poor environmental conditions. On the other hand, the reason why this drug contributes to good growth is currently unknown. For example, it prevents Milcarb or its metabolites from reducing the effectiveness of calcium peroxide by microorganisms. Microorganisms that grow under waterlogged conditions in the presence of calcium peroxide, and Milcarb or its metabolites will eliminate those that cause problems to rice germination and seedling establishment under adverse environmental conditions, or will grow to the extent that they do not cause any problems. to prevent It is conceivable that Milcarb and its metabolites absorbed into paddy rice seeds or seedlings after emergence confer resistance to external growth-inhibiting factors to paddy rice seedlings under poor environmental conditions. The usefulness of the present invention will be explained below by showing test examples. Test Example 1 Test on rich soil As shown in Table 1, 3% of Tachigaren 4% powder and 1 portion of Milcarb 12.5% solution were added to Calper powder in an amount equal to the weight of dry rice, as shown in Table 1.
%, 2%, and 4%, and coated paddy rice seeds (variety: Nipponbare) in a conventional manner. Paddy soil where 20 of these flour-coated seeds were submerged under water.
1g of chemical fertilizer per 500g (contains 8% each of N, P, and K)
After mixing with Fuyeongsei conditions, 1.5cm below the soil surface layer.
The seeds were sown at the location of After sowing, the seeds were flooded with 3 cm of water and placed in a pyotron at 25°C during the day and 20°C at night (12 hours each), and the number of sprouts was investigated over time. The test was conducted twice, and the results are shown in the table below as an average value.

[Table] Test example 2 Test on reduced soil To 250 g of air-dried paddy soil, add 1 g of glucose and twice the amount of water as the soil, mix thoroughly, and then reduce the average temperature.
The soil was kept at 23°C for two weeks to prepare reduced soil. To this soil, add 3% of Tachigaren 4% powder to Calper powder and Milcarb powder as in Test Example 1.
Paddy rice seeds (variety Koshihikari) coated with 12.5% solution mixed in advance to 2% and 4%
20 seeds each were sown 1.5 cm below the surface layer and maintained in a biotron at a submergence depth of 3 cm and a temperature of 25°C during the day and 25°C at night (12 hours each). The average number of sprouts is shown in the table below.

[Table] As is clear from the above test examples, a significant increase in the number of germination was observed in all seeds coated with Millcarb added to Calper powder. In other words, it is clear that the agent of the present invention prevents the effect of Calper powder from diminishing under both conditions, including artificially enriched soil and strong reduction prepared by mixing glucose into the soil. be. Test Example 3 Test in a field in Kashimadai Town, Miyagi Prefecture Calper powder, which is a mixture of paddy rice seeds (variety: Sasanishiki) with predetermined amounts of 4% Tachigaren powder and 12.5% Milcarb solution, was used in an amount equal to the dry weight of the paddy, and powdered in a conventional manner. dressed. The seeds coated as described above were sown at a rate of 7 kg per 10 ares in a portion approximately 1 cm below the soil surface of a paddy field flooded on May 7th, and then submerged in water to a depth of approximately 3 cm. Four weeks after sowing, seedling establishment rate and plant height were investigated.
The test was conducted three times in a 6 m ² area, and the average soil temperature during this period was 11 to 17°C. The average values of the results are shown in Table 3.

[Table] Test Example 4 Test in a field in Takanezawa Town, Tochigi Prefecture Similarly to Test Example 3, predetermined amounts of Tachigaren 4% powder and Milcarb 12.5% liquid were mixed with Calper powder, and rice seeds (variety Hatsuboshi) were coated with the powder. did. Flour-coated seeds at a rate of 7 kg per 10 ares,
On May 15th, the seeds were sown and grown according to Test Example 3.
After 4 weeks, the seedling establishment rate and plant height were investigated. The average temperature during this period was 11-16℃, and the average soil temperature was 15-22℃. The average values of the results are shown in Table 4.

[Table] As is clear from Tables 3 and 4, the agent of the present invention significantly improved the seedling establishment rate and plant height even under field conditions. Examples Examples are shown below. Example 1 98 parts by weight of Calper powder, 2 parts by weight of Milcarb 12.5% liquid, and 50 parts by weight of a thorough mixture of the above were added to salt water-sorted paddy rice seeds with a specific gravity of 1.13 in an equal amount per weight of dry rice.
Dusted with water.

Claims (1)

[Claims] 1. A powder coating agent for rice seeds for direct sowing in flooded soil containing calcium peroxide and 5-butyl-2-dimethylamino-6-methylpyrimidin-4-ol.