JP2023172485A - Method for producing cassava seedling, method for producing cassava, and method for preserving cassava stem - Google Patents

Abstract

To provide a method for producing cassava seedlings that can increase the yield of cassava tubers, a method for producing a cassava that can increase the yield of cassava tubers and the yield of starch, and a method of preserving cassava stems that can prevent the cassava stems from withering due to low temperatures.SOLUTION: A method for producing cassava seedlings includes immersing cassava (Manihot esculenta) stems in water or a liquid fertilizer for 4-24 hours.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing cassava seedlings, a method for producing cassava, and a method for preserving cassava branches.

Cassava (Manihot esculenta, hereinafter the same) is a tuberous root crop native to Central and South America that has been described as the "crop of the 21st century" by the Food and Agriculture Organization of the United Nations (FAO). The main production areas are concentrated in tropical regions, but due to its high yield and environmental adaptability, its cultivation area is being expanded to marginal environments on the periphery of tropical regions.

The cassava harvest residue, the branches, are used as seeds for the next crop. In tropical regions where year-round cultivation is possible, production efficiency is increased by dividing the field and rotating harvest and planting sequentially. On the other hand, in marginal environments, it is difficult to introduce year-round cultivation due to various environmental factors that vary from region to region, such as severe dry seasons or low-temperature winters, and excessive humidity due to excessive rainfall. In remote environments, it is common to introduce one crop per year, excluding periods that are unsuitable for cultivation. For example, in Kagoshima Prefecture, which is located in a remote area, both the above-ground and underground parts of cassava wilt due to low temperatures in winter, so the period when cassava can be cultivated is approximately from April to December.

As a method for improving the yield of cassava, Patent Document 1 discloses, for example, a method for cultivating cassava that includes feeding oligosaccharides to young cassava seedlings. Patent Document 2 discloses that a physiologically active solution containing a water-soluble oil or a water-miscible oil and water is brought into contact with a plant by spraying or the like in order to modify the growth of the plant. Patent Document 3 discloses the use of a composition containing Bacillus amyloliquefaciens RTI472 strain for promoting plant growth. Patent Document 4 discloses a method for increasing the production and yield of staple food crops, which includes contacting cassava or the like with a plant hormone-like compound.

JP2022-24682A Special table 2019-536747 publication Special table 2018-508472 publication International Publication No. 2011/010695

Demand for cassava is increasing not only for food but also as a raw material for various industries such as starch and alcohol. Further increases in cassava yields are desired not only in marginal environments where cassava is cultivated during short, limited warm periods, but also in tropical regions.

The present invention has been made in view of the above-mentioned circumstances, and provides a method for producing cassava seedlings that can increase the yield of tuberous roots of cassava, a method for producing cassava that can increase the yield of tuberous roots and starch yield of cassava, and a low temperature. To provide a method for preserving cassava branches that can prevent the withering of cassava branches due to drying at a low cost.

(Manufacturing method for cassava seedlings)
The method for producing cassava seedlings described herein includes soaking cassava branches in water or liquid fertilizer for 4 to 24 hours.

The liquid fertilizer may include nitrogen, phosphorus, and potassium.

In the method for producing cassava seedlings described in this specification, cassava seedlings are kept in a container installed in an unheated house and having an outlet for discharging internal water during a period when the daily minimum temperature is less than 5°C. The cassava branches covered with a transparent covering and preserved may be immersed with the base side buried in sand.

(Manufacturing method for cassava seedlings)
In the method for producing cassava seedlings described herein, the cassava seedlings are kept in a container that is installed in an unheated house and has an outlet for discharging the water inside during a period when the daily minimum temperature is less than 5°C. The method includes preserving the cassava branches by covering them with a transparent covering while the base side of the cassava branches is buried in sand.

(Manufacturing method of cassava)
The method for producing cassava described in this specification includes growing cassava seedlings for 100 days or more under conditions where the daily minimum temperature does not fall below 5° C. after planting the cassava seedlings.

The method for producing cassava may further include harvesting the cassava after the day when the daily minimum temperature becomes 5° C. or less.

The cassava seedlings in the cassava production method may be cassava branches soaked in water or liquid fertilizer for 4 to 24 hours.

(How to preserve cassava branches)
The method for preserving cassava branches described herein consists of cassava branches whose base side is buried in sand held in a container having an outlet for discharging internal water and covered with a transparent covering. This includes leaving the product in an unheated house for a period when the daily minimum temperature is less than 5°C.

(How to preserve cassava branches)
The method for preserving cassava branches during the period when the daily minimum temperature is less than 5°C described in this specification is to store cassava branches in a container installed in an unheated house and having an outlet for discharging the water inside. The method includes burying a base side of a cassava branch in sand, and covering the cassava branch with a transparent covering.

In the method for preserving cassava branches, the sand in which the base side of the cassava branches is buried is irrigated, or the sand may be irrigated after the base side of the cassava branches is buried.

The volumetric water content of the sand during the storage period may be 5% or more and 25% or less.

The method for preserving cassava branches may further include checking the volumetric moisture content every 2 to 6 weeks during the storage period, and watering if it is less than 5%.

According to the method for producing cassava seedlings according to the present invention, it is possible to increase the yield of tuberous roots of cassava. According to the method for producing cassava according to the present invention, the tuber yield and starch yield of cassava can be increased. Furthermore, according to the method for preserving cassava branches according to the present invention, it is possible to prevent cassava branches from dying due to low temperatures at low cost.

It is a diagram showing the daily minimum temperature in Kagoshima Prefecture. (A) shows the daily minimum temperature for seven months from September 2019, September 2020, and September 2021. (B) shows the daily minimum temperature from December to January shown in (A). FIG. 7 is a diagram for explaining a method for preserving cassava branches according to Embodiment 3; (A) is a diagram showing a cross section of a container that holds sand. (B) is a diagram showing a cross section of a container with cassava branches standing in sand. (C) is a cross-sectional view of a container with the lower end side of the cassava branches buried in sand. FIG. 3 is a diagram showing changes in water absorption rate of cassava seedlings according to Example 1. FIG. 3 is a diagram showing the dry matter percentage of cassava roots according to Example 3. There are significant differences between groups labeled with different letters.

Embodiments according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments and drawings. Note that in the embodiments below, expressions such as "have," "include," or "contain" also include the meanings of "consisting of" or "consisting of."

(Embodiment 1 Method for producing cassava seedlings)
As cassava seedlings, the lower 20 cm of the cassava branches are cut out and used. Poor growth and death of cassava seedlings are factors that reduce yield per land area. By the method for producing cassava seedlings according to the present embodiment, cassava seedlings that quickly root and promote germination can be obtained.

The method for producing cassava seedlings according to the present embodiment includes soaking cassava branches in water or liquid fertilizer. The type of cassava is not particularly limited, and examples include bitter varieties and sweet varieties. The cassava branches are, for example, cassava branches whose branches have been removed after harvesting. The length of branches used as cassava seedlings is 5 to 50 cm or 10 to 35 cm, preferably 15 to 25 cm. Preferably the length of the branches is 20 cm. As a cassava seedling, the lower part (base side) of the branch is particularly preferable.

The liquid fertilizer is not particularly limited as long as it is a known liquid used as a fertilizer. Preferably, the liquid fertilizer contains at least nitrogen, phosphorus, and potassium (also referred to as "potash"). The concentration of liquid fertilizer is preferably the concentration used for watering the base of the plant. Specifically, the concentration of nitrogen in the liquid fertilizer is, for example, 20 to 60 ppm or 30 to 50 ppm. Preferably, the concentration of nitrogen in the liquid fertilizer is 35-45 ppm. The concentration of phosphorus in the liquid fertilizer is, for example, 40 to 120 ppm, 60 to 100 ppm, or 70 to 90 ppm. Preferably, the concentration of phosphorus in the liquid fertilizer is 75-85 ppm. The concentration of potassium in the liquid fertilizer is, for example, 10 to 90 ppm, 20 to 80 ppm, or 30 to 70 ppm. Preferably, the concentration of potassium in the liquid fertilizer is 50-60 ppm. In addition to the above-mentioned components, the liquid fertilizer may further contain trace elements of magnesium, manganese, and boron.

As shown in Example 1 below, the water absorption rate of cassava branches is fastest in the first hour after soaking, absorbing 50% of the total water absorption by 4 hours, and thereafter continues to absorb water slowly. The amount of water absorbed reaches its maximum after about 12 hours of immersion. Therefore, the time for soaking the cassava branches in water or liquid fertilizer is 4 hours or more, preferably 4 to 24 hours, 4 to 20 hours, 4 to 16 hours, or 4 to 12 hours. Alternatively, the soaking time may not be set to these fixed times, but may be set to a time at which 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more of the total water absorption amount is absorbed by the branches. can.

Soaking can be done in any manner as long as the branches are immersed in water or liquid fertilizer. For example, the branches may be placed in a container or other container filled with water or liquid fertilizer. In order to prevent the branches from floating to the surface of the liquid and leaving part of the branches unexposed to the water or liquid fertilizer, it is preferable to use a weight or the like to maintain the entire branch submerged in the water or liquid fertilizer.

The soaked branches can be planted as cassava seedlings. The cultivation method may be normal cutting cultivation. Cultivation areas are tropical, subtropical and marginal environments. In marginal environments in the northern hemisphere, it is preferable to plant between March and May. To illustrate the cultivation method below, first, before planting, a starter fertilizer is applied in the field and the field is deeply plowed to form ridges. Since drainage is important for cassava cultivation, it is preferable to set the ridge height to a high value of 20 to 30 cm. It is preferable that the ridge width is 80 to 100 cm, and the ridge spacing is about 90 to 120 cm. Plant cassava seedlings in holes dug about the same length as the cassava seedlings, with a spacing of about 50 to 120 cm, cover with soil, and press lightly. After planting, the seeds will germinate in about a week, but fertilizing, soiling, watering, etc. until harvest can be done according to known methods. The roots can be harvested by pulling out the plants 9 to 11 months after planting.

As shown in Example 2 below, the cassava seedlings obtained by the method for producing cassava seedlings according to the present embodiment have a higher budding rate, which is the number of sprouts relative to the number of axillary buds, compared to cassava seedlings that have not been immersed in water or liquid fertilizer. The survival rate, which is the number of established individuals with both buds and roots after planting, was high, and the dry weight of seedlings and leaf area were large. The method for producing cassava seedlings according to the present embodiment improves the survival ability of cassava seedlings and promotes their initial growth. As a result, the yield of tuberous roots of cassava can be increased.

(Embodiment 2 Cassava manufacturing method)
Figure 1 (A) shows the daily minimum temperature in Kagoshima Prefecture from 2019 to 2021. Figure 1 (B) shows the daily minimum temperatures from December to January in Figure 1 (A). In 2019 and 2021, there were consecutive days when the daily minimum temperature was below 5℃ after the end of December, and in 2020 after mid-December. The inventor observed cassava from late September and found that when the daily minimum temperature was 5° C. or lower for consecutive days, low-temperature damage appeared in the tuberous roots and above-ground parts. Specifically, low-temperature damage includes rotting inside the tuberous roots, water-soaked roots, and black spots on the surface of the tuberous roots. Withering of leaves and new shoots is also observed due to low temperature damage.

Therefore, when growing cassava in a marginal environment, especially in an area with a winter season and days when the minimum temperature is below 5°C, the tuber yield and starch content are maximized, and the tuber quality before the onset of cold damage is maintained. It is preferable to harvest cassava in a dripping state. For example, in Kagoshima Prefecture, as shown in Example 3 below, both the above-ground and underground parts continue to grow until about 200 days after planting. Tuberous root enlargement begins around 100 days after planting and continues over time, but the increase is particularly remarkable at the final stage of growth (175 to 196 days). The dry matter percentage of the tuberous root, which can be considered as the starch content, continues to increase over time, but there is no difference at the final stage of growth (175 to 196 days). Therefore, it is advisable to grow it for at least 100 days or more and harvest it while the tuber quality is maintained. As mentioned above, low temperature damage appears when the daily minimum temperature is 5 degrees Celsius or less in a row, so the optimum harvest time for cassava is when the daily minimum temperature is 5 degrees Celsius or less.

The method for producing cassava according to the present embodiment includes growing cassava seedlings for 100 days or more under conditions where the daily minimum temperature does not fall below 5° C. after planting the cassava seedlings. After growing for 100 days or more under conditions where the daily minimum temperature does not fall below 5°C, cassava is harvested after the day when the daily minimum temperature falls below 5°C. The timing of planting is determined by counting backwards from the average yearly period when the daily minimum temperature is below 5 degrees Celsius to ensure a growing period of at least 100 days. In order to maximize the tuber yield and starch content, it is preferable that the above-ground and underground parts reach their final stages of growth just before the daily minimum temperature drops below 5°C. Therefore, cassava may be grown for, for example, 100 to 200 days, 150 to 200 days, preferably 175 to 200 days, during which the daily minimum temperature does not fall below 5°C. Taking Kagoshima Prefecture as an example, cassava seedlings should be planted between March and May, and harvested after the daily minimum temperature is below 5°C (for example, from late November to December).

According to the method for producing cassava according to the present embodiment, it is possible to sufficiently grow cassava and to prevent the quality of tuberous roots from deteriorating due to low temperature damage. Thereby, the tuber yield and starch yield of cassava can be increased.

Note that the cassava seedlings planted using the cassava production method according to the present embodiment may be the cassava seedlings produced using the cassava seedling production method according to the first embodiment. By doing so, as described in the first embodiment, the initial growth of cassava seedlings is promoted, and the yield of cassava tuberous roots can be further increased.

(Embodiment 3 Method for preserving cassava branches)
In areas where the daily minimum temperature is less than 5 degrees Celsius during the winter, cassava cannot survive the winter due to the low temperatures, so it is necessary to use the saved branches as seedlings for the next crop. Branches are larger than seeds, and in order to preserve large quantities of branches, it is necessary to store them intensively. However, heating greenhouses are costly and the branches begin to grow during storage, making them less useful as seeds. Therefore, in the present embodiment, a method for preserving cassava branches during a period when the daily minimum temperature is less than 5° C. is provided.

The method for preserving cassava branches is to bury the base side in sand held in a container with an outlet for discharging the internal water, and then place the cassava branches covered with a transparent covering in an unheated greenhouse. This includes standing still for a period when the daily minimum temperature is less than 5°C.

Sand is clastic particles with a particle size of 62.5 μm to 2 mm. There are no particular limitations on the material as long as it is sand, but river sand is preferred. The container is, for example, a container or a planter that is provided with a drain port and has an open top surface. Although the volume of the container is not particularly limited, it is preferable that the area of the sand when viewed from above of the container holding the sand is an area that allows insertion of a plurality of branches, for example 10 to 15 branches. The height of the container is preferably 10 cm or more.

More specifically, one aspect of the method for preserving cassava branches will be described with reference to FIG. 2. As shown in FIG. 2(A), a container 3 equipped with a drain port 2 on the bottom holds sand 4 to a height of about 5 cm from the bottom. As shown in FIG. 2(B), a plurality of cassava branches 1 are gathered into a bundle with a rope or the like and erected in a container 3 with their bases facing the sand 4. Branches 1 are obtained by removing branches from collected branches and cutting them into 1 to 1.5 m lengths. It should be noted that there may be a plurality of bundles of branches 1, and in that case, the plurality of bundles may be gathered together with a rope or the like to prevent them from falling down.

Subsequently, the base side of the cassava branches 1 is buried in the sand 4 held in the container 3. For example, as shown in FIG. 2(C), 5 to 10 cm from the lower end of the branch 1 is filled with sand 4. As the sand 4, sand that has been irrigated in advance may be used, or the sand 4 may be irrigated after the base side of the branch 1 is buried. For example, watering may be performed on the sand 4 and branches 1 in the state shown in FIG. 2(C) until drainage is confirmed from the drain port 2 of the container 3.

Next, the cassava branches 1 are covered with a transparent covering 5. The material of the covering 5 is not particularly limited as long as it is transparent and can keep the inside including the branches 1 warm, and examples thereof include a plastic sheet, an agricultural polyvinyl chloride film, an agricultural polyolefin film, and the like. In order to further retain heat, the container 3 as well as the branches 1 may be covered with a covering 5. The coating is not limited to one layer, but may be two or three layers.

It is desirable that the unheated house in which the container 3 is installed maintains the shutoff temperature as much as possible. The volumetric moisture content of the sand 4 during the storage period is, for example, 5% or more and 25% or less. The method for preserving cassava branches may further include checking the volumetric moisture content every 2 to 6 weeks during the storage period, and watering if it is less than 5%.

When the daily minimum temperature reaches 5° C. or higher, the covering 5 is removed and the cassava seedlings can be used. The lateral buds at the top two to three nodes of the branch 1 are easy to sprout, and the already sprouted branch 1 is difficult to use as seedlings, so the base side may be cut to about 20 cm and used as cassava seedlings.

As shown in Example 4 below, the survival rate of cassava seedlings obtained from cassava branches preserved in winter using the preservation method according to the present embodiment was high. According to the method for preserving cassava branches according to the present embodiment, by using a non-heating house, the elongation of branches during the storage period can be kept to a minimum while preventing the withering of branches due to low temperatures. It can be prevented.

Note that the method for preserving cassava branches according to the present embodiment can be incorporated into the method for producing cassava seedlings according to the first embodiment. That is, in the method for producing cassava seedlings according to Embodiment 1 above, during a period when the daily minimum temperature is less than 5°C, cassava seedlings are kept in a container installed in an unheated house and having an outlet for discharging the water inside. Cassava branches covered with a transparent coating and preserved may be immersed with the base side buried in the sand.

The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited by the examples.

Example 1: Study on priming of cassava seedlings The weight of nine seedlings of cassava (variety: Tokunoshima White) cut into 20 cm lengths was measured. The seedlings were immersed in water so that they were completely submerged. The seedlings were taken out and weighed at 1, 2.5, 3.75, 10, 16 and 24 hours after soaking. Since the weight of the seedlings before soaking affects the water absorption amount, the water absorption amount was calculated in terms of 1 g of seedlings per hour.

(result)
The branches, which are the raw material for cassava seedlings, are less lignified than the tips and absorb water better, while the base absorbs water more slowly. The total water absorption of the seedlings used in this test after 24-hour soaking varied from 132.4 to 280.4 mg gFW ^-1 per gram of seedlings, reflecting the nature of the branches from which they were sourced. Figure 3 shows the changes in water absorption rate of cassava seedlings. The water absorption pattern was similar regardless of the total amount of water absorbed, and the water absorption rate was highest immediately after immersion and decreased with increasing immersion time. The amount of water absorbed 4 hours after the start of immersion reached 50.1% compared to after 24 hours. After soaking, all the seedlings were planted and confirmed that they had taken root.

Example 2: Examination of promotion of early growth by priming Branches of cassava (variety: Tokunoshima White) were cut into 20 cm pieces, soaked in liquid fertilizer or water for 21 hours, and used for planting. The content of fertilizer components in the liquid fertilizer used was 40 ppm nitrogen, 77 ppm phosphorus, 55 ppm potassium, 10 ppm magnesium, 0.27 ppm manganese, and 0.55 ppm boron. The cultivation site was a glass greenhouse attached to the Faculty of Agriculture, Kagoshima University. Branches that were not soaked were used as a control. A 15 x 60 cm plastic pot was filled with vermiculite, thoroughly watered, and the seedlings were planted using diagonal cuttings (implemented on May 12, 2021). The number of planted plants was 9 seedlings/pot for each treatment, and after that, they were managed by installing a sunshade to avoid direct sunlight and watering as appropriate. The number of iterations is 3.

The water absorption amount was determined by dividing the weight change before and after soaking by the weight of the seedling before soaking. 22 days after planting (June 3, 2021), 5 seedlings were randomly extracted from one repetition of each treatment, and the number of axillary buds in the seedlings and the presence or absence of sprouting (number of sprouts) were investigated. The number of sprouts per seedling was divided by the number of axillary buds per seedling to obtain the sprout rate. Twenty-two days after planting, all seedlings were examined for sprouting and rooting, and seedlings having both buds and roots were counted as rooted individuals. The survival rate was calculated by dividing the number of established individuals by the number of planted seedlings. Twenty-two days after planting, three individuals per replicate of each treatment plot were excavated, separated into leaves, new shoots, seedlings, and roots, dried in an oven at 80°C for 3 days with ventilation, and weighed. The area of the leaves was measured using a leaf area meter before drying. Since the weight of cassava seedlings varies significantly depending on the thickness of the branches used for preparation, the weight of newly generated leaves, new shoots, and roots was summed to determine the dry weight of the seedlings.

(result)
Table 1 shows the water absorption, germination rate, survival rate, seedling dry weight, and leaf area for each treatment. In particular, priming with liquid fertilizer increased the germination rate, survival rate, seedling dry weight, and leaf area. It has been shown that immersion in water or liquid fertilizer increases the viability of cassava seedlings and promotes early growth.

Example 3: Examination of the influence of harvest time on starch accumulation in cassava Cassava seedlings (variety: Tokunoshima White) were planted at a farm attached to the Faculty of Agriculture, Kagoshima University (May 18, 2021). The planting density was 2 plants per 1 m ² (row spacing 1 m, plant spacing 0.5 m, ridge height 0.3 m, using black mulch). N fertilizer, P fertilizer, and K fertilizer were used at 8 kg/10 a each during row setting. Samples were taken 135 days, 154 days, 175 days and 196 days after planting, and the organ dry weight, tuber dry weight percentage, and amylose and amylopectin amounts in tuberous roots were measured using an amylose/amylopectin analysis kit (K-AMYL 06/18, Megazyme Inc.). The measurement was carried out using the following kit (manufactured by J.D.) according to the instructions attached to the kit.

(result)
Table 2 shows the dry weight of each organ. Total dry weight and tuber dry weight increased as the cultivation period increased. As shown in FIG. 4, the tuberous root dry matter rate, which is an index of the starch content of the tuberous root, increased until 175 days after planting, but the increase thereafter was small. The amylose/amylopectin ratio was not affected by the sampling period and remained almost constant. These results revealed that the parameters related to starch accumulation changed in different patterns, and the dry weight of the tuber reached its maximum at the latest.

Example 4: Evaluation of preservation method of cassava branches The survival rate of seedlings obtained from cassava branches preserved in winter as described below was investigated. In Survey A, we started preserving branches on December 13, 2019, and started raising seedlings on April 7, 2020. In Survey B, we started preserving branches on December 11, 2020, and started raising seedlings on May 12, 2021. In Survey C, we started preserving branches on December 10, 2021, and started raising seedlings on April 18, 2022. The survey dates for Survey A, Survey B, and Survey C were April 27, 2020, June 3, 2021, and May 17, 2022, respectively. In Survey A and Survey B, Tokunoshima White was used, and in Survey C, Tokunoshima Yellow was used.

Branches were removed from the cassava branches and bundled into lengths of 1 to 1.5 m. Inside a non-heated vinyl house, a container filled with about half of river sand was placed with the base of the branches facing down on the river sand, and the entire container was secured with string so that it could stand on its own. A container was filled with river sand so that the lower ends of the branches were covered with sand, and water was applied until drainage was confirmed from the drainage port provided in the container. The branches and container were covered three times with transparent plastic sheets. Subsequent watering was carried out once every 3 to 4 weeks to avoid excessive humidity, and the volumetric water content was maintained in the range of 5 to 25%. The plastic sheets were removed when the daily minimum temperature did not fall below 5°C. Since sprouting and partial death occurred from the tips of the shoots, the tips and the base where rooting had begun were removed to obtain homogeneous seedlings.

For seedling raising, the branches that had been preserved over the winter as described above were cut into 20 cm lengths and used as seedlings. Seedlings were pricked diagonally into a planter (60 x 15 x 15 cm) filled with vermiculite, watered, and cultivated in the shade in a glass greenhouse.

In the survey, individuals in which root expansion and leaves were observed in 10 seedlings per repetition were considered as established individuals, and the survival rate was determined. The number of replicates for Study A, Study B and Study C are 9, 9 and 18, respectively.

(result)
The survival rates in Survey A, Survey B, and Survey C were 70.0%, 91.8%, and 82.2%, respectively. The survival rate was high in all years, and it was a useful preservation method for different varieties.

The embodiments described above are for explaining the present invention, and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims rather than the embodiments. Various modifications made within the scope of the claims and the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

The present invention is useful for producing cassava.

1 Cassava branches, 2 Drainage port, 3 Container, 4 Sand, 5 Covering material

Claims (12)

The method includes soaking cassava (Manihot esculenta) branches in water or liquid fertilizer for 4 to 24 hours.
Method for producing cassava seedlings. The liquid fertilizer is
Contains nitrogen, phosphorus and potassium,
The method for producing cassava seedlings according to claim 1. During the period when the daily minimum temperature is less than 5 degrees Celsius, the base side is buried in sand kept in a container with an outlet for discharging the internal water installed in an unheated house. soaking the cassava branches covered and preserved;
The method for producing cassava seedlings according to claim 1 or 2. During periods when the daily minimum temperature is less than 5°C, the base side of the branches of cassava (Manihot esculenta) is buried in sand kept in a container with an outlet for discharging the water inside, which is installed in an unheated house. Preserving the cassava branches by covering them with a transparent covering in a state where the cassava branches are
Method for producing cassava seedlings. After planting cassava (Manihot esculenta) seedlings, growing them for 100 days or more under conditions where the daily minimum temperature does not fall below 5°C,
How to produce cassava. further including harvesting cassava after the day when the daily minimum temperature is below 5℃;
The method for producing cassava according to claim 5. The cassava seedlings are
Cassava branches soaked in water or liquid fertilizer for 4 to 24 hours.
The method for producing cassava according to claim 5 or 6. Branches of cassava (Manihot esculenta), whose bases were buried in sand and covered with a transparent covering, were held in a container with an outlet for discharging internal water, and were placed in an unheated house at the lowest daily temperature. Including standing still for a period of less than 5 degrees Celsius,
How to preserve cassava branches. A method for preserving cassava (Manihot esculenta) branches during a period when the daily minimum temperature is less than 5°C, comprising:
burying the base side of the cassava branches in sand held in a container installed in an unheated house and having an outlet for discharging internal water;
covering the cassava branches with a transparent covering;
How to preserve cassava branches, including: The sand in which the base side of the cassava branches is buried is irrigated, or
The sand is irrigated after burying the base side of the cassava branches;
The method for preserving cassava branches according to claim 9. The volumetric moisture content of the sand during the storage period is 5% or more and 25% or less,
The method for preserving cassava branches according to claim 9 or 10. further comprising checking the volumetric moisture content every 2 to 6 weeks during the storage period, and irrigating if it is less than 5%.
The method for preserving cassava branches according to claim 11.