Method for cultivating paddy rice in regenerative multiple cropping system

Abstract

Provided is a method for cultivating paddy rice in a regenerative multiple cropping system enabling increase in yield by increasing the number of harvests per year, while suppressing use of chemical fertilizers and agrochemicals in subtropical, tropical, and temperate regions. The method for cultivating paddy rice in a regenerative multiple cropping system comprises the steps of: raising seedlings; performing shallow-water soil puddling in a paddy field; performing rice planting or direct sowing; forming ridges by making grooves in the paddy field; and reaping while leaving a predetermined length from the base. The step of raising seedling preferably includes a step of applying VA mycorrhizal fungi to the seed rice. Furthermore, it is preferable to further provide a step of scattering straw over the paddy field between the step of performing shallow-water soil puddling and the step of performing rice planting.

Description

Method for Cultivating Multiple Crops of Rice by Regeneration

[0001] The present invention relates to a method for cultivating multiple crops of rice by regeneration.

[0002] Conventionally, in subtropical regions, tropical regions, and temperate regions, the number of rice harvests in a year is 2, and at most 3. Since the yield of indica rice per harvest is about 350 kg - 400 kg / 10a in paddy rice, the yield limit in a year is about 700 kg - 800 kg / 10a. The yield of japonica rice per harvest is about 550 kg in rough brown rice.

[0003] For example, in Patent Document 1, using an indica rice variety for edible rice, early cultivation of rice is carried out for the first time. After the first harvest, "hikobae" generated from the cut plants is grown to cultivate rice for the second time, and the second harvest is carried out. A method for cultivating two crops of rice by regeneration is disclosed, in which the deterioration of the taste of the rice obtained in the second harvest compared with the rice obtained in the first harvest is suppressed.

[0004] Japanese Unexamined Patent Application Publication No. 2023 - 172956

[0005] However, in recent years, due to the soaring prices of chemical fertilizers and pesticides, it is necessary to grow rice in a state close to organic cultivation without using chemical fertilizers and pesticides. Furthermore, there is a problem that the yield cannot be increased because the number of harvests in a year is small in the first place.

[0006] Therefore, an object of the present invention is to provide a method for cultivating multiple crops of rice by regeneration that can increase the number of harvests in a year while suppressing the use of chemical fertilizers and pesticides in subtropical regions, tropical regions, and temperate regions.

[0007] In order to achieve the above object, the method for cultivating multiple crops of rice by regeneration of the present invention includes a step of raising seedlings, a step of shallow water weeding in a paddy field, a step of transplanting or direct seeding, a step of cutting grooves in the paddy field to make ridges, and a step of cutting leaving a predetermined length from the base of the plant.

[0008] As described above, the rice regeneration multi-cropping cultivation method of the present invention comprises the steps of raising seedlings, preparing the paddy field with shallow water, transplanting or direct seeding, creating furrows in the paddy field, and harvesting the rice, leaving a predetermined length from the base of the plant. With such a rice regeneration multi-cropping cultivation method, it is possible to increase the number of harvests per year while suppressing the use of chemical fertilizers and pesticides in subtropical, tropical, and temperate regions.

[0009] This is a flowchart showing the procedure for the rice regeneration multi-cropping method. This is a photograph of the rice harvest of the first crop. This is a photograph of the rice after the first crop has been harvested. This is a photograph of the "sprouts" 10 days after the first crop has been harvested. This is a photograph of the harvest period for the second crop. This is the cultivation calendar for rice planting in the Philippines. (a) is a regeneration multi-cropping method with 15 cm remaining at the base of the plant, and (b) is a regeneration multi-cropping method with 35 cm remaining at the base of the plant. This is the cultivation calendar for direct seeding in the Philippines. (a) is a regeneration multi-cropping method with 15 cm remaining at the base of the plant, and (b) is a regeneration multi-cropping method with 35 cm remaining at the base of the plant. This is the cultivation calendar for Hyogo Prefecture. (a) is for conventional farming, and (b) is for regeneration double cropping. This is the cultivation calendar for Okinawa Prefecture. (a) is for conventional double cropping, and (b) is for regeneration multi-cropping.

[0010] Embodiments of the present invention will be described below with reference to the drawings. However, the components described in the following embodiments are illustrative and are not intended to limit the technical scope of the present invention to them alone.

[0011] (Configuration of the water-saving irrigation system) First, the components of the water-saving irrigation system S of the present invention will be explained. The water-saving irrigation system S of the present invention consists of the following elements: a) Making low ridges (approximately 10-15 cm high) in the rice paddy. b) Straw mulch c) VA mycorrhizal fungi d) Seedling cultivation (including soaking and germination) e) Rice planting (planting seedlings by machine or by hand), or direct sowing of germinated seeds. f) Regenerating the two-season crop to produce three or more seasons. g) Using separate irrigation and drainage channels for open waterways. Drainage technology from the rice paddy. h) Cultivation calendar (harvest prediction) (system using Excel®: self-created) i) Field harvesting management (investigating 4 plants x 4 plants in the field) to understand the state of soil fertility.

[0012] a) Ridges are formed by cutting furrows in the rice paddy. The width of the ridges will be the width of the tire tracks left by the rice transplanter. This can be used as a reference when planting by hand. In this case, areas where furrows have not been cut will result in ridges that are convex upwards. Areas where the soil has been pushed up towards the ridge by the furrow cutter should be leveled by hand to improve drainage on the ridge side. The height of the ridges should preferably be 10 cm to 15 cm.

[0013] b) Straw mulch: Finely chopped straw (cut into 5-20 cm pieces) is spread by a combine harvester and this is called "straw mulch." Therefore, the combine harvester should be of a type that can cut straw. In the case of hand harvesting, straw that has been threshed and cut into 5-20 cm pieces is used.

[0014] c) VA Mycorrhizal Fungi: Mycorrhizae are a group of fungi and mushrooms (mycorrhizal fungi) that produce vesicles (sac-like structures) and arbuscules (resinous structures), and are beneficial microorganisms that attach to plants. VA mycorrhizal fungi attach to plant roots and extend their hyphae into the soil, efficiently absorbing minerals such as phosphate and water to supply to the plant, and providing sugars produced by photosynthesis.

[0015] (Regenerative Multi-Crop Cultivation Method) Next, the procedure for the regenerative multi-cropping method of rice using the water-saving irrigation system S described above will be explained. The regenerative multi-cropping method of rice according to the present invention consists of steps / elements 1) to 12).

[0016] 1) Rice planting should take place during a period of abundant rainfall. In tropical regions, this is the rainy season; in subtropical and temperate regions, it is the rainy season. 2) Seedlings should be raised in preparation for rice planting (Step 1). At this time, a small amount of VA mycorrhizal fungus should be attached to the rice seeds. This seedling raising process includes soaking and germination. 3) The rice paddy should be plowed with shallow water (Step 2). It is preferable to use rainwater for this purpose. 4) Straw should be spread in the rice paddy (Step 3). 5) Rice planting should be done (Step 4). (Machine planting or hand planting) or germinated seeds should be directly sown. 6) Ditches should be made (Step 5). The width of the ditches should be the width of the rice transplanter's tire tracks. This should be used as a reference when planting by hand. The areas without ditches will become ridges. Where the soil has piled up on the ridge side due to the ditching machine, the soil should be leveled by hand to improve drainage on the ridge side. 7) The straw on the ridges has a weed-killing effect. Also, the straw acts as fertilizer. Furthermore, the straw helps retain water in the ridges. 8) Since VA mycorrhizal fungi are aerobic, drain the water from the rice paddy as much as possible (step 6) (water conservation). However, do not drain the water from the rice paddy until it becomes dry, but drain it just enough to maintain a moist state. 9) Water conservation is necessary during the heading stage (step 7). The straw on the ridges prevents the soil from drying out. VA mycorrhizal fungi draw water out from the ground. 10) Harvest by cutting the plants about 10-40 cm from the base (step 8) (regeneration for two crops; see Figures 2-5). The length of the part left from the base is determined according to the variety being cultivated. The same length should be used whether using a combine harvester or harvesting by hand. In particular, there are limits to how high a combine harvester can cut. The tracks of the machine may press down on (knock down) the plants. 11) Spread straw (cut into 5-20 cm pieces) between the plants (step 9). Use a combine harvester that can cut straw. If harvesting by hand, cut the straw after threshing into 5-20 cm pieces. 12) The first crop is as described in steps 1) to 9). The second crop is the same up to harvesting in steps 10-11. For multi-cropping from the third crop onwards, steps 10-11 are repeated. In other words, by using the regeneration multi-cropping method of the present invention, it becomes possible not only to regenerate two crops, but also to regenerate three or more crops—especially multi-cropping including four or five crops.

[0017] In the regenerative multi-cropping method described above, the water level (distance from the top of the ridge) is as follows: • Dry season water level: 1-10 cm (hot season water level: 5-13 cm) • Rainy season water level: 0-2 cm

[0018] (Advantages) Next, the advantages of the rice regeneration multi-cropping method using the water-saving irrigation system S described above will be explained. The rice regeneration multi-cropping method of the present invention has the following advantages and features: (1) to (6).

[0019] (1) It is important for the multi-cropping method of rice cultivation using water-saving irrigation systems to be implemented at the local level. If it is implemented only in some rice paddies, damage from birds will be concentrated. (2) In tropical regions, there is a "dry season" and a "hot season," so the land dries out. However, this drying can be prevented by laying straw on the ridges (straw mulch). (3) There is a lot of rain during the "rainy season." Since VA mycorrhizal fungi are aerobic, open drainage channels should be provided. (4) Straw mulch is effective against weeds. (5) Based on the harvest time predicted by the cultivation calendar, there are four or five harvest times in a year. In other words, with Indica rice, if the yield per harvest is 400 kg / 10a of paddy rice, then 1600 to 2000 kg / 10a can be expected. With Japonica rice, if the yield per harvest is 500 kg / 10a of raw brown rice, then 1000-1500 kg / 10a can be expected. (6) When regenerating and multi-cropping is carried out, soil fertility decreases. This can be evaluated by measuring the yield per tsubo (harvesting rice from one tsubo and using that as the basis to calculate the total yield). If the evaluation determines that soil fertility has decreased, proceed from "Procedure 1) Rice planting". Rice planting must take place during the rainy season.

[0020] (Evaluation) (1) In tropical and subtropical regions, conventional methods require 120 to 150 days from the last rice harvest, puddling, and planting to the next harvest. With regenerative multi-cropping, although it varies depending on the height at which the rice is cut from the base of the plant, the harvest time is about 70 days. (2) The temperature required for rice to grow is 16°C or higher. Tropical and subtropical regions fully meet this condition. (3) Regarding temperature, subtropical regions (Okinawa region) and temperate regions also meet the conditions. (Harvest forecast) If sterility occurs during the winter, the rice will be harvested while still green. The harvested rice will be used as cattle feed (it will become WCS feed). (4) Chemical fertilizers and pesticides will not be necessary. In the future, it will become organically grown rice. If the soil fertility has declined, organic fertilizer will be spread on the rice paddy and plowed in, and planting will start again after a certain period of time.

[0021] (Points to note) In order to distribute the damage caused by birds, this project needs to be undertaken by the entire community. Alternatively, countermeasures need to be implemented throughout the entire community.

[0022] (Effects) Next, the effects of the rice regeneration multi-cropping method of this embodiment will be listed and explained.

[0023] (1) As described above, the present invention provides a method for cultivating rice through regeneration multiple crops, comprising the steps of raising seedlings, preparing the paddy field with shallow water, transplanting or direct seeding, creating furrows in the paddy field, and harvesting the rice, leaving a predetermined length from the base of the plant. With such a method for cultivating rice through regeneration multiple crops, it is possible to increase the yield by increasing the number of harvests per year while suppressing the use of chemical fertilizers and pesticides in subtropical, tropical, and temperate regions.

[0024] (2) Furthermore, the seedling cultivation process includes the step of attaching VA mycorrhizal fungi to the rice seeds (germinated rice). The VA mycorrhizal fungi attach to the roots of the rice plants and extend their hyphae into the soil, efficiently absorbing minerals such as phosphorus and water and supplying them to the rice plants, which in turn provide the rice plants with sugars produced by photosynthesis. Moreover, because VA mycorrhizal fungi are aerobic, rice can be grown sufficiently even in climates with periods of little rain.

[0025] (3) Furthermore, it is preferable to include a step of spreading straw in the rice paddy between the step of shallow water plowing and the step of rice planting. By spreading straw, the straw on the ridges has a weed-killing effect, the straw also serves as fertilizer, and it also has the effect of preventing the evaporation of water in the rice paddy.

[0026] (4) Furthermore, by adding a step to drain the water from the rice paddy between the process of making ridges and the process of harvesting, the aerobic VA mycorrhizal fungi will become more active, and the growth of the rice will be promoted.

[0027] (5) Furthermore, by having the rice paddy water drained when heading occurs, the straw on the ridges prevents the soil from drying out, while the VA mycorrhizal fungi draw moisture out from the ground.

[0028] (6) Furthermore, since the harvesting process involves cutting the rice while leaving 10 cm to 40 cm from the base of the plant, adjusting the length left according to the rice variety can promote rice growth and enable regenerative multi-season cropping.

[0029] (7) Furthermore, since the process includes a step of scattering cut straw between the plants after the harvesting process, the drying of the soil is suppressed by the straw, and nutrients from the straw are released into the soil, so that rice can be cultivated without using chemical fertilizers.

[0030] (8) Furthermore, with the above-mentioned method of regenerating and multi-cropping rice, by repeating the harvesting process at least three times, it becomes possible to cultivate more than three crops, which was previously impossible.

[0031] Next, using Figures 6 to 9, we will explain the simulation results of actual cultivation calendars in the Philippines and Japan (Hyogo Prefecture and Okinawa Prefecture).

[0032] First, using Figures 6 (rice planting) and 7 (direct seeding), we will explain the cultivation calendars for rice planting and direct seeding in the Philippines by comparing them.

[0033] In the case of rice planting, as shown in Figure 6(a), harvesting with a combine harvester leaves 15 cm of soil around the base of the plant, resulting in a longer regrowth period. If the first planting is done on June 1st, the fourth harvest will be on March 28th. This means that the fifth "sprout" will appear on March 29th, and the harvest will be on June 4th, which is not feasible. Therefore, four regrowth crops are the limit. As a result, the annual yield is 1490 kg, and the annual yield increase rate is 199%.

[0034] In the case of rice planting, as shown in Figure 6(b), harvesting by hand while leaving 35 cm of the base of the plant shortens the regrowth period. If the first planting is done on June 1st, the fourth harvest will be on March 2nd. This means that the fifth "sprout" will appear on March 3rd, and the harvest will be on April 29th. As a result, five regrowth crops become possible. Consequently, the annual yield will be 1890 kg, and the annual yield increase rate will be 252%.

[0035] (Discussion) - Leaving the roots longer from the base of the plant promotes faster growth, increasing the annual yield. - Here, November to February was considered the dry season, March to May the hot season, and June to October the rainy season. - After germination, VA mycorrhizal fungi were attached. - Seedlings were transplanted when they were about 20 cm tall.

[0036] In the case of direct seeding, as shown in Figure 7(a), harvesting with a combine harvester leaves 15 cm of soil around the base of the plant, resulting in a longer regrowth period. If the first direct seeding is done on June 1st, the fourth harvest will be on April 5th. This means that the fifth "sprout" will appear on April 6th, and the harvest will be on June 13th, which is not feasible. Therefore, four regrowth crops are the limit. As a result, the annual yield is 1490 kg, and the annual yield increase rate is 199%.

[0037] In the case of direct seeding, as shown in Figure 7(b), harvesting by hand while leaving 35 cm of the base of the plant shortens the regrowth period. If the first direct seeding is done on June 1st, the fourth harvest will be on March 12th. This means that the fifth "sprout" will appear on March 13th, and the harvest will be on May 10th. As a result, five regrowth crops become possible. Consequently, the annual yield will be 1890 kg, and the annual yield increase rate will be 252%.

[0038] (Discussion) - Leaving the stems longer from the base of the plant promotes faster growth, increasing the annual yield. - Here, November to February was considered the dry season, March to May the hot season, and June to October the rainy season. - After germination, VA mycorrhizal fungi were attached. - For direct sowing, germinated rice was sown directly into the rice paddy.

[0039] Next, using Figures 8 (Hyogo Prefecture) and 9 (Okinawa Prefecture), we will explain the cultivation calendars in Hyogo Prefecture and Okinawa Prefecture, Japan, by comparing them. In both cases, (a) is the conventional farming method, and (b) is the regenerative multi-cropping method of the present invention.

[0040] In Hyogo Prefecture, as shown in Figure 8(a), conventional farming is a single-crop system. In the case of the present invention, with combined harvesting leaving 15 cm of soil around the base of the plants, as shown in Figure 8(b), if the first planting is done on April 1st, the first harvest will be on August 1st. Then, the second sprout will appear on August 2nd, and the second harvest will be on October 26th. This makes a second regeneration crop possible. As a result, the annual yield will be 1100 kg, and the annual yield will increase by 200%.

[0041] In Okinawa Prefecture, as shown in Figure 9(a), conventional farming involves two cropping seasons. In the case of the present invention's regenerative multi-cropping method, if rice is harvested with a combine harvester leaving 15 cm of soil around the base of the plant, as shown in Figure 9(b), if the first planting is done on March 2nd, the third harvest will be on October 28th. This means that the fourth sprout will appear on October 29th, and the harvest will be on February 4th. However, it is better not to harvest at this stage. Therefore, a third regenerative cropping season becomes possible. As a result, the annual yield will be 1200 kg, and the annual yield increase rate will be 150%.

[0042] (Discussion) - In Japan, rice is harvested using a combine harvester. The rice is cut 15 cm from the base of the plant. - Here, December-February is considered winter, March-May is spring, June is the rainy season, July-September is summer, and October-November is autumn. - After germination, VA mycorrhizal fungi are attached. - Seedlings are transplanted when they are about 20 cm tall.

[0043] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design modifications that do not depart from the spirit of the present invention are included in the present invention.

Claims

1. A method for cultivating rice for multiple seasons, comprising the steps of: raising seedlings; preparing the paddy field with shallow water; transplanting or direct seeding; digging furrows in the paddy field to create ridges; and harvesting the rice, leaving a predetermined length from the base of the plant.

2. The method for cultivating rice for multiple crops, according to claim 1, wherein the seedling cultivation step includes the step of attaching VA mycorrhizal fungi to the rice seeds.

3. The method for cultivating rice for multiple crops, according to claim 2, further comprising the step of spreading straw in the rice paddy between the step of shallow water plowing and the step of rice planting.

4. The method for cultivating rice for multiple crops, according to claim 3, further comprising a step of draining water from the rice paddy between the step of making ridges and the step of harvesting.

5. A method for cultivating rice for regeneration and multiple cropping as described in claim 4, wherein the rice reaches the heading stage with the water in the paddy field drained.

6. The method for cultivating rice for multiple crops, as described in claim 1, wherein the harvesting step is a step of harvesting while leaving 10 cm to 40 cm from the base of the plant.

7. A method for cultivating rice for multiple crops, according to any one of claims 1 to 6, further comprising the step of scattering cut straw between the rice plants after the harvesting step.

8. The method for cultivating rice for multiple crops, according to claim 7, wherein the harvesting step is repeated at least three times.

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