JP2516330B2 - How to promote rice seed germination - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for promoting germination of paddy rice seeds.

[Conventional technology]

Traditionally, rice cultivation, which is a major crop in Japan, has been dominated by rice planting. In recent years, cultivation by the direct sowing method in submerged soil has been popularized for the purpose of labor saving and increase in yield.

In this cultivation method, unlike direct flooding, inoculation of paddy rice seeds in a submerged soil at a seeding depth of 1 to 2 cm provides the same effect as the appropriate inoculation depth, which is an advantage of the rice planting method. be able to. Therefore, it is possible to avoid defects such as floating seedlings, falling seedlings, or lodging due to a typhoon before harvesting, which are observed in submerged direct seeding cultivation without covering with soil. In addition, since there is no effect of physical force on the seedlings seen in the transplant method, it is possible to expect an increase in the yield as the number of seeds is increased by proper growth management. However, this direct sowing method in submerged soil causes problems such as a lower germination rate and a lower seedling establishment rate because the oxygen supply required for the sown seeds to germinate is insufficient. There are drawbacks.

As a method for preventing this decrease in germination rate and further promoting germination, Japanese Patent Publication Nos. 47-28751, 53-46726, 55-22045 and the like disclose calcium peroxide on seeds by dressing. To supply oxygen.

[Problems to be Solved by the Invention]

Even when the seeds are dressed in this way, the number of days from seeding to emergence is long, especially in the zone where seeds are sown when the average temperature is low, so the calcium peroxide dressing decomposes relatively quickly. , Has difficulty in supplying oxygen continuously. In addition, if the amount used is increased to make up for this point and the oxygen supply to the periphery of the seeds is attempted to continue, phytotoxicity to the paddy rice due to calcium hydroxide generated in the decomposition process of calcium peroxide occurs.

[Means for solving the problem]

The present inventor, including these known methods, as a result of various investigations, using magnesium peroxide as an active ingredient, an inorganic fixing agent for facilitating dressing such as calcined gypsum as an auxiliary ingredient. The present invention has been completed, and it was found that the germination can be accelerated and the emergence rate can be significantly improved by dressing paddy rice seeds with the seeds.

As the fixing agent here, a powder coating is used easily and surely, and a compound having water of crystallization is used. As these compounds, for example, anhydrous salts of calcium sulfate, 1/2 hydrate, anhydrous salts of magnesium sulfate,
Inorganic compounds such as 1, 2, 4, 5, 6, 6 and 7 hydrates may be mentioned.

When an organic compound such as a water-soluble polymer is used as the adhesive agent, the dressing process is not as simple as the inorganic adhesive agent, and the storability of the dressed rice is deteriorated.

A first feature of the present invention is that the dressing can continuously supply oxygen even when the period in which the seed needs oxygen for germination is prolonged.

The paddy rice seeds dressed with magnesium peroxide according to the present invention, the magnesium peroxide in the dressing part is gradually decomposed in the paddy water to generate oxygen, and the decomposition rate is the same as that of the prior art calcium peroxide. It's about 2/3 slower than the comparison.

As a result, the number of days from sowing to germination becomes longer, especially in the zone where seeds are sown when the average temperature is low, so magnesium peroxide can be gradually decomposed during this period and oxygen can be continuously supplied to the periphery of the seeds. This is far more advantageous than that of magnesium peroxide, which decomposes relatively quickly.

In actual agricultural management, the sowing time for direct sowing in submerged soil is determined by various factors such as the region and subsequent crops, but it is usually 5 in Kyushu and Chushikoku regions, which are temperate regions.
It is from late May to late June, mid May in the Kanto region, and early to mid May in the Tohoku / Hokkaido regions. The average temperature at this sowing time fluctuates significantly, about 23-25 ℃ in Kyushu area, about 20 ℃ in Kanto area, and about 15 ℃ in the north of Tohoku area.

The number of days until emergence of paddy rice seeds in direct sowing cultivation in flooded soil varies slightly depending on the variety, but it is generally calculated by the following formula. The number of days until emergence x days is: x days = 50 ÷ (average temperature -10) In an area where the average temperature is around 20 ° C, after about 5 days, the average temperature is
It is known that if the temperature is around 15 ° C, it will start to sprout after about 10 days, and the number of days until sprout will increase due to the decrease in average temperature.

The second feature of the present invention is that the phytotoxicity of the dressing on rice is reduced.

Both magnesium peroxide and calcium peroxide coated on paddy rice seeds decompose in field water to generate oxygen, and in the process of decomposition, magnesium hydroxide,
Calcium hydroxide is produced and these are distributed around the seed.

The pH value of calcium hydroxide under saturated conditions for water is
12.5, which shows strong alkalinity, magnesium hydroxide exhibits a pH value of 10.5 under the same water saturation conditions. Under actual field conditions, it is thought that neutralization by acidic substances in the environment will alleviate strong alkalinity, but
The adverse effect of the generated hydroxide on the seeds is considerably reduced with magnesium peroxide. This advantage is effective in a situation where a means for increasing the amount of calcium peroxide cannot be taken in order to extend the period during which oxygen can be supplied in cold regions.

In order to carry out the present invention, it is usually 20 to 30% as an active ingredient.
1 part by weight of a powder coating preparation containing magnesium peroxide of
It is preferable to coat 1 part by weight of rice seeds. It is possible to increase the amount as needed, and even in that case, there is no risk of chemical damage to paddy rice due to the increase in magnesium hydroxide produced.

As for the dressing method, a general method of adding magnesium peroxide and a dressing preparation containing calcined gypsum as a fixing agent to a paddy rice seed rotated on a turntable together with an appropriate amount of water is appropriately adopted. can do.

Furthermore, in dressing, a fertilizer, a pest control agent, a plant growth regulator, etc. may be added, if necessary, and calcium peroxide may be mixed with magnesium peroxide in an arbitrary ratio.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to Examples.

Test Example 1 A 1-volume beaker was filled with paddy soil, and the water depth was 3 cm.
Water was added so that

Then, a powdered preparation of calcium peroxide and magnesium peroxide having the same effective oxygen concentration was prepared so that the amount of oxygen generated by decomposition would be the same. That is, each contains 28% of magnesium peroxide and 35% of calcium peroxide, and both contain 25% of calcined gypsum as a fixing agent for dressing, and the balance is adjusted with calcium carbonate to prepare 1 weight each of the preparation. 1 part by weight of paddy rice seed was stirred while adding water, and powdered.

From the soil surface of the beaker, 20 seeds of each of the powdered rice seeds were buried at a depth of 1 cm, and left in a thermostat at 20 ° C.

Remove the powdered seeds from the soil with tweezers over 3 days, 7 days, and 14 days after transfer to the incubator, carefully peel off the powdered seeds from the seeds, and remove the magnesium peroxide and excess peroxide remaining in the area. Calcium oxide was analyzed by the method of titrating with potassium permanganate to determine the decomposition rate.

 The results are shown in Table 1.

As is clear from Table 1, the decomposition of magnesium peroxide under flooded water is slower than that of calcium peroxide.
It is understood that oxygen can be continuously supplied to the periphery of the seed gradually over a long period of time.

Test Example 2 A 1/5000 Wagner pot was filled with paddy soil, and water was added to a water depth of 3 cm. According to Test Example 1, a dressing preparation containing 28% and 35% of magnesium peroxide and calcium peroxide, respectively, was prepared so that the effective oxygen concentration was the same, and 1 weight of paddy rice seed (varieties beetle) was prepared. 1 part by weight of the prepared dressing preparation was coated on each part.

Forty seeds of each dressing seed obtained in this way were sown in a prepared Wagner pot so that the soil cover depth would be 2 cm, and then the pot was placed at 19 ° C (high temperature zone) and 14 ° C (low temperature zone) at room temperature. It was left standing in the artificial weather box set with. The number of repeats was 4.

The germination rate was measured after 9 days, 12 days, and 14 days, respectively, when the cells were left at room temperature of 19 ° C. Table 2 shows the results. In addition, for those left at room temperature of 14 ° C, the emergence rate after 21 days and the length of shoots of seedlings were measured. The results are shown in Table 3.

As is apparent from Tables 2 and 3, the paddy rice seeds dressed with magnesium peroxide began to germinate early in both low temperature and high temperature groups and showed a good germination rate, and the bud length of the germinated seedlings was also Apparently the extension is promoted.

In practical use, particularly in the submerged soil direct seeding cultivation method in an area having a low average temperature, actively maintaining the initial growth is a very important point in the cultivation management after the growth, and the usefulness of the present invention is it is obvious.

Test Example 3 20 ml of a solution prepared by adjusting calcium hydroxide and magnesium hydroxide so as to have a predetermined concentration (a suspension partly having a saturated concentration or more) was placed in a petri dish having a diameter of 9 cm, and paddy rice seed ( 10 varieties of Koshihikari) were placed, the growth was controlled in a thermostat at 17 ° C., and the leaf length of the seedlings emerged after 7 days was measured. The results are shown in Table 4.

As is clear from Table 4, in the case of calcium hydroxide, growth inhibition was observed in rice with increasing concentration.

Example 1 Magnesium peroxide containing 45% of active ingredient 63 parts Calcined gypsum 25 〃 Calcium carbonate 12 〃 The above mixture was mixed to obtain a dressing preparation having an effective oxygen concentration of about 8%.

In advance, 1 part by weight of the selected paddy rice seeds (cultivar Nihonbare) was washed with a saline solution having a specific gravity of 1.13, and then the water was changed daily and immersed for 4 days. After the immersion water was drained off, the seeds were disinfected by immersing it in a 2,000-fold solution of Benlate-T (bactericide, trademark of DuPont) for 24 hours.

The seeds were placed in a rotary dressing device, and 1 part by weight of the above-prepared dressing preparation of the present invention and 0.05 parts by weight of water were gradually added while rotating at a speed of 23 revolutions per minute for about 20 minutes. Completed the dressing with.

On the other hand, with respect to the calcium peroxide as a control, a powdered drug formulation containing 72 parts of calcium peroxide containing 50% of active ingredient, 25 g of plaster of gypsum 25 〃 of calcium carbonate and 3 〃 of effective oxygen concentration was prepared. It was dressed according to the magnesium oxide dressing formulation.

Then, using a hand-operated seeder (manufactured by Taki Nogyo Co., Ltd.), the depth of approximately 2c
The seeds were sown in an amount of about 4 grams per square meter of rice. Immediately after sowing, the number of seed grains per 1 m of seeding row in several randomly surveyed plots was measured, and the average value was used as the estimated value of the actual seeding number.

 Then, water was added so that the water depth was 3 cm.

Seven, 9, 12, and 14 days after sowing, the number of sprouting per 1m of the seeding line in the survey area was set to 4 and the number of sprouting was estimated in advance. The sprouting rate was calculated with the denominator as.

The average temperature before and after sowing in this example was about 18 ° C. The results are shown in Table 5.

As is apparent from the above table, the dressed seeds of magnesium peroxide according to the present invention have a germination start date that is at least 2 days earlier than that of the control calcium peroxide, and the germination rate after 2 weeks is significantly increased. are doing.

Example 2 Magnesium peroxide containing 45% of active ingredient 63 parts Magnesium sulfate / monohydrate 8 〃 Calcium carbonate 29 〃 The above ingredients were mixed to obtain a dressing preparation having an effective oxygen concentration of about 8%.

Pre-selected salt water-seeded rice seeds (cultivar Koganebale)
1 part by weight of water was changed every day for 4 days, the immersion water was drained off, and the seeds were disinfected by immersing the solution in 2,000 times of Benlate T for 24 hours.

The seeds were placed in a rotary dressing machine, and 1 part by weight of the above-prepared dressing preparation according to the present invention and 0.05 part by weight of water were gradually added while rotating at a speed of 23 rotations per minute to give about 20 parts.
Completed dressing in minutes.

On the other hand, with respect to the calcium peroxide as a control, a powdered drug formulation containing 72 parts of calcium peroxide containing 50% of active ingredient, 25 g of plaster of gypsum 25 〃 of calcium carbonate and 3 〃 of effective oxygen concentration was prepared. The powder coating treatment was performed in the same manner as the magnesium oxide powder coating formulation.

Then, using an input type seeder (OH-192 type manufactured by Mukai Kogyo Co., Ltd.) on the paddy field under submerged conditions that had been preliminarily submerged,
The seeds were sown in a size of 1.5 cm in an amount of about 3 grams per square meter of rice. Immediately after sowing, seeds per one meter of the seeding seed were dug up in four randomly surveyed plots, the number of seeds was measured, and this was averaged to obtain an estimated value of the actual number of seeds.

 Then, water was poured so that the water depth was 4 cm.

Five, seven, nine and twelve days after sowing, the number of sprouting per meter of seeding row was measured in the survey area with a randomly selected repeat number of 4, and this was dug immediately after sowing. The emergence rate (%) was calculated by using the measured actual number of seeds as a denominator.

The average temperature before and after sowing in this example was about 23 ° C.

 The results are shown in Table 6.

As is clear from Table 6, the magnesium peroxide dressed seeds according to the present invention started to germinate earlier than the control calcium peroxide dressed seeds, and a significant increase in the germination rate was observed at each measurement. It was

〔The invention's effect〕

According to the method of the present invention for promoting germination of paddy rice seeds,
Degradation of magnesium peroxide in paddy water is slower than that of calcium peroxide and can supply oxygen to seeds for a long period of time. In addition, the decomposition product magnesium hydroxide has a lower pH than calcium hydroxide and is less likely to cause chemical damage to rice. When rice seeds are sown by the method of the present invention in paddy soil under flooded conditions, germination starts early and the emergence rate is improved. In particular, the effect is remarkably exhibited in cold regions where calcium peroxide cannot be used.

Claims (1)

(57) [Claims] 1. A method for promoting germination of paddy rice seeds, which comprises dressing paddy rice seeds with magnesium peroxide and an inorganic fixing agent.