JPH0640786B2 - Rice cultivation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for cultivating rice.

[Conventional technology]

In Japan, general rice cultivation begins with seed selection in the spring, sowing, germination, and transplantation, followed by harvesting in the fall. During this time, the rice transplanted to the cultivated fields such as rice fields is
It grows and bears fruit after the earing stage, heading stage, flowering period, and ripening period.

[Problems to be solved by the invention]

In rice cultivation, the factors that determine the yield per unit area are the number of spikes per unit area, the number of paddy per spike,
Four points are the grain ripening rate of paddy and the weight per thousand grains of brown rice. Of these, the number of ears per unit area is determined by the number of rice stalks that connect the ears per unit area of planting, that is, the number of effective split stalks.

When transplanting seedlings, several seedlings are planted as one strain at regular intervals in the cultivated land. Therefore, the effective number of stalks per unit area is equal to the number of rice strains per unit area and 1
It is the product of the number of effective stalks per plant. However, from these calculations, simply increasing the number of stocks per acreage or increasing the number of rice plants per stock will make the growing environment worse due to the overcrowding of the rice plants, and will not only increase the number of effective divisions. ， Inducing weakening of rice.

As the rice grows from the seedling, the stem grows from the knot part of the parent stem, and the stem grows further, and further split from the split stem. Good rice grows from the lower node of the parent stalk, and secondary stalks from the stalk are also popular.

The division of rice begins shortly after the transplanting period after transplanting, and the number of stems gradually increases as the rice grows. The number of stems reached its maximum several days before the differentiation stage of panicles, then some stems died without ears, and the remaining stalks had ears and ripened. The latter stem with the spike is called the effective split stem, and the former stem that dies without the spike is called the invalid split stem.

For example, when cultivating Koshihikari in a paddy field downstream of the Tone River, which is a rice plant in the Kanto region, a maximum splitting period is reached about every 45 days after transplanting seedlings, and so-called four-planting with four parent stems per plant. The number of stems is around 20 in this strain. After that, about 20% of the above-mentioned number of stems died as ineffective stalks during the larval differentiation stage, and the remaining 16 ears have ears.

Another problem in rice cultivation is lodging of rice during the ripening period. Fallen rice not only makes it difficult to reap, but also causes various problems. If the rice has many ears and the rate of ripening is large, the rice is more likely to lodge, and particularly varieties such as Koshihikari and Sasanishiki are lodged easily. The lodging of rice is related not only to the thickness of the stem but also to the internodal distance. It is said that the rice that is exposed to sufficient sunlight during the internodal extension period to avoid overcrowding and excess nitrogen fertilizer is less likely to lodge.

In the present situation of conventional rice cultivation, the inventor of the present invention secures a larger number of effective split stalks without reducing the number of paddy per spike in order to obtain a larger yield per unit area planted, Moreover, we examined whether it would be possible to make rice that is durable and hard to lodge. The present invention has been completed as a result of the above investigation.

[Means for solving problems]

That is, the present invention is for cultivating rice from rice planting to harvesting, and it usually takes 40 to 40 m ² of cultivated land area for a few days to several tens of days before reaching the highest splitting period and from sunset to sunrise. The light is applied to the rice plant for about 10 hours with the light intensity of a fluorescent lamp of 40 W as a guide.

〔Example〕

Next, examples of the present invention will be described together with comparative examples, and desirable embodiments will also be described.

The table below shows the fields in Shintone Village, Inashiki District, Ibaraki Prefecture.
After transplanting Koshihikari seedlings sown on March 15th on May 5th, rice is experimentally cultivated under the same conditions by the method according to the present invention and a conventional method. Four seedlings were planted, and the number of stems was the average number of stems per strain. The total length is the average length from the root to the tip of the rice. In the remarks column, (a) shows the example, and (b) shows the comparative example.

The relationship between the date and the number of stems is also shown in the graph in Fig. 1.

The seedlings transplanted to the rice fields on May 5 are divided according to their growth, and the initial number is 4 parent stems per plant, with 12 or 15 stems.
The number of books continued to increase to 25, reaching an average of 40 between June 20 and July 1. In other words, this time is the highest season for normal rice.

In the present invention, irradiation of the rice with light is started several days before reaching the highest parting period. For example, in the example, irradiation was started on June 15. Light is applied for several hours in at least one of the time zones before sunrise or after sunset. In the case of the example, irradiation was performed every day for 10 hours on average until the sun disappeared every day. The illuminating light is good from a fluorescent lamp. Taking the case of a general daylight fluorescent lamp as an example, the brightness of about 40 W of fluorescent light per 40 m ² of cultivated area is a standard.

After that, in the rice of the comparative example which was not irradiated with light, about 20% of the split stems died after the maximum splitting period, and the number of stems became about 32. Then, in July, 10 to 20 days have passed since the best parting period
Young ears are seen around the 10th, and 7 to 20 to 25 days later.
Heading started about 30 days a month. Then, the ears were gathered around August 5 and cut on September 5. The average height of rice at that time was 115 cm, and the number of stems with spikes, that is, the number of effective stalks was 32 per plant.

On the other hand, in the examples irradiated with light, the division of rice still continued even after the normal maximum division period, and the number of stems continued to increase. That is, after the start of light irradiation on June 15, the number of stalks reached 40 on the 20th, and the number of stalks continued to increase until August 1 when the light irradiation was stopped, reaching a maximum of 104.
During that time, no panicles are observed.

After that, about a few percent of the stalks withered and became so-called ineffective stalks, but 14 days after the light irradiation was stopped, young ears were confirmed on August 15, and heading started on August 30. . Then, the ears were gathered on September 5, and they could be harvested on October 5. The total length of rice when cut is 130c
The number of stems with m and spikes, that is, the number of effective split stems was 101. That is, it was an average of 3 stalks per strain that became ineffective tillers.

In this way, by irradiating light, the panicles are advanced, and the panicles are not seen until the irradiation is stopped. This means that the panicles can be differentiated by continuing to irradiate the light until the number of stalks is secured to some extent. It means that you can hold down and continue to divide. However, it is natural that each region has a limitation on the timing of larvae that can be delayed due to the relationship with the climate, but the heading time of rice is controlled to some extent within the range permitted by such environmental conditions. It is possible. Approximately 30 days after the light irradiation is stopped as a guideline for heading.

Next, in each of the Examples and Comparative Examples, 10 cut rice plants were randomly sampled, and the number of paddy grains attached to each ear, that is, the number of grains was examined. As a result, the distribution of the number of grains of each ear per strain was as shown in the table below.

In the example, 101 stems per plant had ears, and in the comparative example 32 ears had ears, but the distribution of the number of particles was almost the same in both cases. In the example, the number of unhulled rice was about three times that of the comparative example.

Furthermore, when the appearance of the cut rice was compared, the length of the rice was not so much changed in the Examples and Comparative Examples, but the stems of the Examples were all thicker than those of the Comparative Examples. Also, while the latter rice plant had 5 parent stems,
The former rice had six parent stems, and the internode distance was shorter than that of the latter rice. Due to these differences, the former rice did not lodge during the ripening period, although the number of panicles was greater than that of the latter rice.

〔The invention's effect〕

As described above, according to the present invention, it is possible to secure a large number of effective split stalks to which ears are to be grown and to cultivate rice that is not prone to lodging without reducing the number of grains per stalk. In addition, the effect of artificially delaying the heading time is also obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the change in the number of stems from transplanting to mowing of rice seedlings for Examples and Comparative Examples of the present invention, and FIG. 2 is a parent of mowed rice for these Examples and Comparative Examples. It is drawing which shows the state of a stem.

Claims (1)

[Claims] 1. When cultivating rice from transplanting seedlings to harvesting, the paddy field of 40 m ² is cultivated in the period from sunset to sunrise for several days to several tens of days before the rice usually reaches the highest splitting period. A method for cultivating rice, which comprises irradiating the rice with light having a light intensity of 40 W per area as a guide for about 10 hours.