Method for producing seedlings

Abstract

To provide methods for producing seedlings having uniform and good quality in a short period of time after seeding that can adjust the sowing time and the shipping time.SOLUTION: The present invention provides a method for producing seedlings comprising a germination step of sowing seeds of woody plants in a cultivation soil, adjusting the temperature of the cultivation soil so that the average cultivation soil temperature, which is the average value, is 20 to 30°C and so that the fluctuation range between the temperature of the cultivation soil and the average cultivation soil temperature is ± 5°C. Preferably, the method further comprises a seedling raising step of raising young seedlings obtained in the germination step to obtain plantable seedlings.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing seedlings. [Background technology]

[0002] Seedling production methods are divided into two categories: bare seedling production, where seedlings are raised in fields, and container seedling production, where seedlings are transplanted or directly sowed using various methods. Most general producers produce bare seedlings in the open, but due to factors such as the sowing season being limited to March and April, there is not enough time to raise the seedlings, and it takes more than two years to ship them, and the shipping season is also limited to February to April (see Non-Patent Document 1). In addition, in outdoor environments, such as below 20°C or in environments with large temperature changes, a long period is required for germination. Furthermore, in high temperature environments (e.g., 40°C or higher), the germination rate generally decreases due to physiological damage.

[0003] Patent Document 1 discloses a technique for cultivating one-year-old seedlings by directly sowing seeds or transplanting seedlings into a multi-cavity container, using an adjustable-efficiency fertilizer and adjusting the fertilizer effect period to be shorter than the seedling raising period, and also adjusting the amount of nitrogen and culture soil used. It is described that this invention provides seedlings with a good establishment rate and growth after planting, with well-developed above-ground parts and root balls, and an increased seedling yield rate.

[0004] Non-patent document 2 describes how, in the production of containerized cedar seedlings, adjusting the amount and type of fertilizer applied during the seedling raising period promotes the growth of seedling height and ground diameter, making it possible to produce containerized cedar seedlings that can be transplanted into the mountains within one year. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-170179 A [Non-patent literature]

[0006] [Non-Patent Document 1] Munehiro Iwakura and 12 others, "Proposal for a new method of producing container seedlings," Forestry and Forest Products Research Institute, 4th Mid- to Long-Term Plan Results 20, published March 15, 2019 http: / / www.ffpri.affrc.go.jp / pubs / chukiseika / documents / 4th-chuukiseika20.pdf [Non-Patent Document 2] Ohira Mineko and 1 other author, "Development of fertilization techniques for producing container seedlings of Japanese cedar in one year," Forestry and Forest Products Research Institute, Timber Breeding Center, Research Results Selection, 2020, p.44-46 https: / / www.ffpri.affrc.go.jp / pubs / seikasenshu / 2020 / documents / p44-45.pdf Summary of the Invention [Problem to be solved by the invention]

[0007] However, although the above-mentioned prior art documents are techniques for promoting the growth of seedlings, they are insufficient for adjusting the sowing time and shipping time, and for efficiently producing seedlings with uniform quality.

[0008] An object of the present invention is to provide a method for producing seedlings of uniform quality in a short period of time after sowing, by adjusting the sowing time and shipping time. [Means for solving the problem]

[0009] The present invention provides the following [1] to [9]. [1] A method for producing seedlings, comprising a germination step of sowing seeds of a woody plant in culture soil, adjusting the temperature of the culture soil so that the average culture soil temperature is 20-30°C and the fluctuation range between the culture soil temperature and the average culture soil temperature is within ±5°C, and obtaining germinated seedlings. [2] The method according to [1], wherein the germination step is carried out during a period when the monthly average temperature is below 20°C or during the period from October to April. [3] The method according to [1] or [2], wherein the germination step lasts for 20 to 50 days from sowing. [4] The method according to any one of [1] to [3], wherein the temperature is adjusted so that the fluctuation range from the average soil temperature is within ±3°C. [5] The method according to any one of [1] to [4], wherein the temperature of the culture soil is adjusted using at least one of an artificial weather machine, a germination chamber, and a horticultural heat-retaining mat. [6] The method for producing seedlings according to any one of [1] to [5], further comprising a seedling raising step of raising the seedlings obtained in the germination step to obtain seedlings suitable for planting. [7] The method for producing seedlings according to any one of [1] to [6], wherein the germinated seedlings are transplanted into a seedling raising pot and then a seedling raising step is carried out. [8] The method for producing seedlings according to [7], wherein the period of the seedling raising process is within 11 months. [9] A method for producing a reforestation area, comprising producing seedlings by the method for producing seedlings according to any one of [1] to [8], and planting the seedlings in the reforestation area. Effect of the Invention

[0010] According to the present invention, germination can be promoted to obtain hairy seedlings in a short period of time, and the subsequent growth can be made uniform, so that a sufficient seedling raising period can be secured according to the shipping time, and good seedlings of uniform quality can be produced at a high yield rate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [1. Seedling production method] As described below, the method for producing seedlings includes a germination step and preferably further includes a seedling raising step. [Germination process] In the germination step, after sowing the seeds of the woody plant, the temperature of the culture soil in the container for raising seedlings before germination is adjusted to 20 to 30° C. This allows the seeds to germinate.

[0012] (Target plants) The target plants are woody plants. For example, Cryptomeria plants (such as Cryptomeria japonica), Chamaecyparis plants (such as Chamaecyparis obtusa), Pinaceae plants (Pinus plants (such as Pinus thunbergii), Larix plants (Larix kaempferi, Larix gmelinii), Abies plants (such as Abies sachalinensis), Eucalyptus plants, Prunus plants (Prunus spp., Prunus mume, Prunus tomentosa), Mangifera plants (Mangifera indica), Acacia plants, Myrica plants, Quercus plants (Quercus acutissima, etc.), Vitis plants, Malus plants, Rosa plants, Camellia plants (Camellia sinensis, etc.), Jacaranda plants (Jacaranda mimosifolia, etc.), Persea plants (Persea americana, etc.), Pyrus plants (Pyrus serotina Rehder, Pyrus pyrifolia, etc.), and Santalum plants (Sandalwood; Santalum album, etc.).Among these, cedar, cypress, pine (Japanese black pine, larch, gmelin, todomatsu, etc.), eucalyptus, cherry, mango, avocado, acacia, bayberry, sawtooth oak, grape, apple, rose, camellia, tea, plum, toadflax, jacaranda, among which plants of the genus Cryptomeria japonica, plants of the genus Chamaecyparis obtusa, plants of the family Pinaceae (plants of the genus Pinus, larch, fir, etc.), eucalyptus plants, camellia plants, mangifera inoculata, and plants of the genus Alligator are preferred, and forest seedlings, i.e., plants of the genus Cryptomeria japonica, plants of the genus Chamaecyparis obtusa, plants of the genus Pinus, plants of the genus Larch, plants of the genus Fir, and plants of the genus Eucalyptus are more preferred, plants of the genus Cryptomeria japonica, plants of the genus Prunus ...

[0013] (Temperature of soil) The temperature of the culture soil is adjusted so that the lower limit of the average value (average value of the temperature of the culture soil in the germination process: average culture soil temperature) is usually 20°C or higher, preferably 21°C or higher, and more preferably 22°C or higher. This allows the seeds to germinate in a short period of time. The upper limit is usually 30°C or lower, preferably 28°C or lower, and more preferably 27°C or lower. This prevents the seeds from drying out and inhibiting germination. Therefore, the average culture soil temperature is adjusted to 20 to 30°C, preferably 21 to 28°C, more preferably 22 to 27°C, and even more preferably 22 to 26°C or 23 to 27°C.

[0014] The temperature of the soil may be maintained at the average soil temperature throughout the germination process, or may fluctuate. The fluctuation range of the soil temperature with respect to the average soil temperature (the difference between the maximum and minimum temperatures and the average soil temperature) is usually ±5°C, preferably ±4°C, more preferably ±3°C, even more preferably ±2°C, and even more preferably ±1°C. This allows germination to be accelerated and germination variation to be suppressed. When the temperature of the soil fluctuates, the maximum and minimum temperatures are preferably within the range of 20 to 30°C.

[0015] (Temperature adjustment means) The temperature of the culture soil can be adjusted using a temperature adjustment means. Examples of the temperature adjustment means include a germination chamber, an artificial weather chamber, and a horticultural heat insulation mat. Among these, the use of a horticultural heat insulation mat is preferable because it allows the temperature of the culture soil to be directly adjusted, and the seedlings are of good quality and the seedling yield is high.

[0016] The temperature of the culture soil can be checked by periodic measurement (for example, every 8 to 15 minutes) using a temperature sensor. The temperature sensor can be placed 1 to 3 cm from the surface of the culture soil.

[0017] (cultivating soil) The culture soil used in the germination step may be any soil capable of controlling the temperature, and may be, for example, natural soil such as sand, soil (e.g., Akadama soil, Kanuma soil), artificial soil such as rice husk charcoal, coconut fiber, vermiculite, perlite, peat moss, glass beads, rice husk, porous molded products such as foamed phenolic resin, rock wool, solidifying agents (e.g., agar or gellan gum), or a combination of two or more of these. Natural soil is preferred, soil is more preferred, and Akadama soil is even more preferred. The particle size of the natural soil is not particularly limited, but fine particles (usually 1 to 2 mm in particle size) are preferred. This allows for good water retention and promotes germination. The coconut fiber is preferably coco peat (coconut husk: fiber obtained from the coconut husk and its residue crushed product).

[0018] (container) Culture soil is usually stored in a container for use. This can facilitate temperature control of the culture soil. The container may be any container with a storage section capable of storing the culture soil, and is preferably a container with an opening at approximately the bottom. Examples include planters and bats (box-shaped containers with an opening at the bottom or side), seedling boxes, containers (e.g., containers described in JP 2017-079706 A, multi-cavity containers (JFA-150, JFA-300: see Non-Patent Document 1), etc.), cell trays, and seedling pots. The size of the container can be appropriately selected based on seedling conditions such as the number of seeds, seeding density, and plant species, and may be for single seed sowing or multiple seed sowing, with the latter (e.g., planters, bats, seedling boxes) being preferred. This allows multiple seeds to be sown and germinated at once, allowing efficient seedling growth. There is no particular limitation on the material of the container for pre-germination seedling growth, and examples include resin, glass, and wood.

[0019] (seeding) Seeding into the soil can be done by a normal method. Seeding can be done by either single seed sowing or multiple seed sowing, but multiple seed sowing is preferred in consideration of seedling raising efficiency. The number of seeds sowed per unit area can be adjusted according to the germination rate. For example, in the case of seeds with a germination rate of 20 to 30%, it is usually 1.3 seeds / cm. 2 More than 1.8 grains / cm, preferably 1.8 grains / cm 2 Above that. The upper limit is usually 3.5 grains / cm 2 Less than 3.0 grains / cm 2 The following is the result.

[0020] (Location of germination process) The germination process can be carried out in a place where the temperature of the culture soil can be controlled, and may be in an open space (e.g., outdoors) or a closed space (e.g., in a vinyl house, an artificial sunlight room, a carbon dioxide gas incubation room, a greenhouse, or indoors).

[0021] (Germination process period) The germination step may be continued at least until germination is observed, which is usually 20 days or more, preferably 25 days or more. The upper limit is usually 45 days or less, preferably 40 days or less. Therefore, it is usually 20 to 45 days, preferably 25 to 40 days, and more preferably about one month.

[0022] (Time of germination process) The germination step is preferably carried out during cold weather. Cold weather means a period when the monthly average temperature is below 20°C or from October to April. By carrying out the germination step during cold weather, the germination period can be shortened and the subsequent seedling raising period can be sufficiently secured, so that seedlings can be produced according to the target shipping time of the seedlings. For example, seedlings that can be shipped around autumn (for example, around October) can be obtained, so that autumn planting is possible in addition to the general spring planting, and a more flexible supply and demand of seedlings can be realized.

[0023] The sown seeds are germinated in the germination step to obtain hairy seedlings. The hairy seedlings are usually at the stage where the cotyledons have expanded, and the size of the above-ground part is usually about 1 to 3 cm, and the overall size including the underground part is about 3 to 5 cm, depending on the length of the roots.

[0024] [Seedling raising process] It is preferable to further carry out a seedling raising step after the germination step. The seedling raising step is a step of raising the seedlings obtained in the germination step.

[0025] (cultivating soil) In the seedling raising step, it is preferable to transplant the hair seedlings from the culture soil used in the germination step to another culture soil. The culture soil can be appropriately selected from the examples of culture soil that can be used in the germination step, taking into consideration water retention, drainage, fertilizer retention, etc., and is preferably a combination of at least one type of artificial soil and at least one type of natural soil, or a combination of at least two types of artificial soil. The natural soil is preferably soil, and Akadama soil and Kanuma soil are more preferable. The size of the soil is preferably small grain (for example, grain size 3 to 6 mm). This can improve drainage. The artificial soil is preferably coconut fiber, peat moss, and vermiculite. The vermiculite may be any of coarse grains (for example, 50% or more of a grain size distribution of 7.0 to 2.5 mm), medium grains (for example, 50% or more of a grain size distribution of 2.5 to 1.2 mm), and fine grains (for example, 50% or more of a grain size distribution of 1.2 mm or less), but coarse grains and medium grains are preferable. The preferred culture soil is a combination of peat moss, Kanuma soil and Akadama soil, or a combination of coconut fiber and vermiculite (medium and fine grains).

[0026] (Container for raising seedlings) In the seedling raising process, a container (seedling raising container) that contains culture soil is usually used. The seedling raising container may be appropriately selected from specific examples of containers that can be used in the germination process, but a container in which seedlings are planted separately one by one, such as a multi-cavity container (JFA-150, JFA-300: see Non-Patent Document 1), a cell tray, or a seedling raising pot, is preferable, and a multi-cavity container or a cell tray is more preferable. This allows efficient production of container seedlings, pot seedlings, or other seedlings suitable for planting.

[0027] (Seedling raising period) The seedling raising step is usually performed for 11 months or less, preferably 10 months or less. The lower limit of the period is usually 7 months or more, preferably 8 months or more, as long as the seedlings are able to be planted in the field.

[0028] (Period from germination to completion of seedling raising process) The period from the germination process to the seedling raising process (from sowing to obtaining seedlings that can be planted in the field) is preferably within 13 months, more preferably within 12 months. This makes it easier to adjust the shipping time.

[0029] (Time of seedling raising process) The timing of the seedling raising step is not particularly limited, but is usually preferred when the monthly average temperature is 5° C. or higher, preferably 10° C. or higher, and more preferably 15° C. or higher, so that concerns about frost damage due to freezing or frost can be avoided.

[0030] (Seeding location) The seedling raising process may be carried out in an open space (e.g., outdoors) or in a closed space (e.g., in a vinyl house, a carbon dioxide gas culture room, a greenhouse, or indoors). The seedling raising process is preferably carried out after transplanting the germinated individuals (hairy seedlings) into seedling raising pots. Since only the germinated individuals (hairy seedlings) can be selected and raised, the seedling yield rate can be improved. In addition, since the environment can be adjusted while observing the seedling raising situation, seedlings of uniform and good quality can be obtained.

[0031] [Optional conditions]

[0032] -Other ingredients (base fertilizer, etc.)- In the germination step and the seedling raising step, which is performed as necessary, the culture soil may be used together with other components. As the other components, for example, base fertilizer and preservatives are preferably included. The inclusion of the base fertilizer can promote the growth of the seedlings. The base fertilizer is not particularly limited, and may be a fast-acting fertilizer or a slow-acting fertilizer, and may be any of inorganic fertilizer, organic fertilizer, and chemical fertilizer. The amount of fertilizer to be applied is not particularly limited, and an amount suitable for the fertilizer to be used can be selected. Examples of components contained in the base fertilizer include components that can be a source of nutrients for plants, such as inorganic components, silver ions, antioxidants, carbon sources, vitamins, amino acids, and plant hormones. The form of the base fertilizer is not particularly limited, and may be either a solid (e.g., powder, granules) or a liquid (e.g., liquid fertilizer).

[0033] Examples of inorganic components include elements such as nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, iron, manganese, zinc, boron, molybdenum, chlorine, iodine, and cobalt, and inorganic salts containing these elements. Examples of the inorganic salts include potassium nitrate, ammonium nitrate, ammonium chloride, sodium nitrate, potassium monohydrogen phosphate, sodium dihydrogen phosphate, potassium chloride, magnesium sulfate, ferrous sulfate, ferric sulfate, manganese sulfate, zinc sulfate, copper sulfate, sodium sulfate, calcium chloride, magnesium chloride, boric acid, molybdenum trioxide, sodium molybdate, potassium iodide, cobalt chloride, and the like, and hydrates thereof. As the inorganic component, one type may be selected from the above specific examples, or two or more types may be combined for use. In the liquid medium used in the present invention, nitrogen, phosphorus, and potassium are preferably contained as essential elements. Therefore, among these specific examples of inorganic components, nitrogen, phosphorus, potassium, inorganic salts containing nitrogen, inorganic salts containing phosphorus, and inorganic salts containing potassium are preferred, and inorganic salts containing nitrogen, phosphorus, potassium, and nitrogen are more preferred. When one type of inorganic component is added, the concentration in the liquid medium is preferably about 1 μM to about 100 mM, and more preferably about 0.1 μM to about 100 mM. When two or more types are added in combination, each of them is preferably added at about 0.1 μM to about 100 mM, and more preferably about 1 μM to about 100 mM.

[0034] Examples of silver ions include silver compounds (silver ion sources) such as silver thiosulfate (STS, AgS4O6) and silver nitrate, which may be used alone or in combination of two or more, with STS being preferred. STS is presumed to take the form of silver thiosulfate ions in the medium and to be negatively charged, which can contribute to promoting healthy root growth and elongation. When silver ions are included, the amount of silver ions is preferably 0.5 μM to 6 μM, more preferably 2 μM to 6 μM.

[0035] Examples of antioxidants include ascorbic acid and sulfites, with ascorbic acid being preferred. Ascorbic acid has low residual capacity in the medium, and therefore can prevent environmental pollution. When an antioxidant is included, the amount is preferably 5 mg / L to 200 mg / L, and more preferably 20 mg / L to 100 mg / L.

[0036] Examples of carbon sources include carbohydrates such as sucrose and their derivatives, organic acids such as fatty acids, and primary alcohols such as ethanol. One of the above specific examples may be selected as the carbon source, or two or more may be used in combination. When a carbon source is included, the amount is preferably 1 g / l to 100 g / l, more preferably 10 g / l to 100 g / l.

[0037] Examples of vitamins include biotin, thiamine (vitamin B1), pyridoxine (vitamin B4), pyridoxal, pyridoxamine, calcium pantothenate, inositol, nicotinic acid, nicotinamide, and riboflavin (vitamin B2). As vitamins, one may be selected from the above specific examples, or two or more may be used in combination. When one vitamin is included, the amount is preferably 0.01 mg / l to 200 mg / l, more preferably 0.02 mg / l to 100 mg / l. When a combination of two or more vitamins is added, the amount of each is preferably 0.01 mg / l to 150 mg / l, more preferably 0.02 mg / l to 100 mg / l.

[0038] Examples of amino acids include glycine, alanine, glutamic acid, cysteine, phenylalanine, and lysine. The amino acids may be used alone or in combination of two or more. When one type of amino acid is used, the amount is preferably 0.1 mg / l to 1000 mg / l, and when two or more types are used in combination, the total amount is preferably 0.2 mg / l to 1000 mg / l.

[0039] As the plant hormones, for example, auxins and / or cytokinins can be used. As the auxins, naphthalene acetic acid (NAA), indole acetic acid (IAA), p-chlorophenoxy acetic acid, 2,4-dichlorophenoxy acetic acid (2,4D), indole butyric acid (IBA) and derivatives thereof can be exemplified, and one or more selected from these can be used in combination. As the cytokinins, benzyladenine (BA), kinetin, zeatin and derivatives thereof can be exemplified, and one or more selected from these can be used in combination. As the plant hormones, only auxins, only cytokinins, or both auxins and cytokinins can be used in combination. When one type of plant hormone is contained, the amount is preferably 0.001 mg / l to 10 mg / l, more preferably 0.01 mg / l to 10 mg / l. In the case of a combination of two or more kinds, the amount of each is preferably 0.001 mg / l to 10 mg / l, and more preferably 0.01 mg / l to 10 mg / l.

[0040] (fertilization) In the germination step and the seedling raising step which is performed as necessary, fertilization may be performed during the seedling raising, and is preferably performed during the seedling raising step. This can promote the growth of the seedlings. As the fertilizer, the same specific examples as those explained as the base fertilizer can be mentioned. The fertilization conditions such as the amount, timing, and method of fertilization are not particularly limited, and a method suitable for the fertilizer to be used can be selected.

[0041] -Irrigation- Watering is usually performed appropriately throughout the germination process and the seedling raising process, which is performed as necessary. The watering method may be either overhead watering or bottom watering. Examples of bottom watering include a method of immersing a seedling raising container (a seedling raising container having an opening) in water and a method of watering the cuttings through a water-absorbing member.

[0042] (temperature) Temperature conditions throughout the germination step and the seedling raising step performed as necessary are not particularly limited, but may be adjusted if necessary. The temperature during the germination step may be adjusted to, for example, a daytime temperature of 15 to 35°C (preferably 20 to 35°C) and a nighttime temperature of 10 to 25°C (preferably 10 to 20°C, more preferably 15 to 20°C).

[0043] (humidity) The humidity can be adjusted according to the cultivation conditions such as the type of plant, but is usually 50% or more, preferably 60% or more. This promotes germination and allows efficient seedling cultivation. There is no particular upper limit.

[0044] (Light Intensity) The light intensity may be adjusted throughout the germination process and, if necessary, the seedling raising process. The light intensity is adjusted so that the photosynthetically active photon flux density is preferably 10 μmol / m 2 / s~1000μmol / m 2 / s, more preferably 50 μmol / m 2 / s~500μmol / m 2 / s, for example, using an irradiation device such as an LED. The wavelength components are preferably adjusted using an agricultural film such as a light quality conversion film so that light containing a wavelength component of 650 nm to 670 nm and a wavelength component of 450 nm to 470 nm is irradiated. The carbon dioxide gas concentration during rooting can be adjusted to usually 300 to 2000 ppm, preferably 800 to 1500 ppm, by placing a culture vessel equipped with a carbon dioxide permeable film in a facility such as an artificial weather chamber. The humidity can be adjusted to usually 60% or more, preferably 80% or more.

[0045] 2. Plantation production methods The seedlings thus obtained can be planted in a planted area or an area to be planted, thereby producing and maintaining the planted area. EXAMPLES

[0046] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

[0047] [Example 1] In December 2019, Japanese cedar seeds were sown in a nursery box (30cm long x 50cm wide x 10cm deep) covered with fine Akadama soil (Yanajima Shoji Co., Ltd.), and the soil temperature was controlled to 24±2°C using an artificial weather device (BioTRON NC350, Nippon Medical and Chemical Equipment Manufacturing Co., Ltd.) to allow for germination. The number of seeds sown was adjusted so that the number of germinated seedlings would exceed 500 based on the specified germination rate of the seeds. Temperature was controlled using an Ondotori (T&D Co., Ltd.) with a sensor placed 2cm deep and measurements taken at 10-minute intervals. Overhead irrigation was performed as appropriate during the germination period.

[0048] After about one month, germinated seedlings were obtained. The seedlings had just expanded cotyledons, and the aboveground part was about 1 to 3 cm in size, with a total size of about 3 to 5 cm. The seedlings were transplanted one seedling per container (JP Patent Publication No. 2017-79706: 24 holes in a 35 cm x 45 cm square) filled with a culture soil mixture of peat moss (manufactured by Sun & Hope Co., Ltd.), Kanuma small grain soil (manufactured by Akagi Engei Co., Ltd.), and Akadama small grain soil (manufactured by Yanashima Shoji Co., Ltd.) at a volume ratio of 4:1:1, and placed in a vinyl greenhouse. During the seedling raising period, overhead irrigation was performed as appropriate, and Hyponex concentrate (manufactured by Hyponex Japan Co., Ltd.) was sprayed once a week at a 500 to 2000-fold dilution.

[0049] Seedling height and base diameter were measured in November 2020. Container seedlings were deemed suitable for transplanting if the average was 30 cm or more and 3.5 mm or more, respectively.

[0050] [Example 2] After sowing, the same procedure as in Example 1 was carried out, except that the management of the culture soil was carried out in a germination chamber and the culture soil temperature was controlled to be 23±3°C.

[0051] [Example 3] After sowing, the management of the soil was carried out in the same manner as in Example 1, except that an agricultural electric horticultural mat (horticultural heat-retaining mat, 1-306 (single-phase 100V 160W, 0.9m x 1.8m), manufactured by Nippon Norden Co., Ltd.) was placed under the seedling boxes in the vinyl greenhouse and the soil temperature was controlled to be 25±2°C.

[0052] [Example 4] The same procedure as in Example 1 was carried out, except that the sowing period was January, the transplanting period was February, and the soil temperature was controlled to be 22±2°C.

[0053] [Example 5] The same procedure as in Example 1 was carried out, except that the sowing period was February, the transplanting period was March, and the soil temperature was controlled to be 26±2°C.

[0054] [Example 6] The same procedure as in Example 1 was carried out, except that the sowing period was March, the transplanting period was April, and the soil temperature was controlled to be 28±2°C.

[0055] [Comparative Example 1] Except for not controlling the temperature of the culture soil and transplanting the germinated seedlings in May of the following year, the same procedure as in Example 1 was carried out. The culture soil temperature until germination was 5±15°C.

[0056] [Comparative Example 2] Except for the fact that the temperature of the culture soil was not controlled and that the period from sowing to transplanting was controlled in a greenhouse, the same procedure as in Example 1 was carried out. The temperature of the culture soil until germination was 10±15°C.

[0057] [Comparative Example 3] Except for sowing in January, the same procedure as in Comparative Example 1 was carried out. The temperature of the soil until germination was 5±15°C.

[0058] [Comparative Example 4] Except for sowing in February, the same procedure as in Comparative Example 1 was carried out. The temperature of the soil until germination was 5±15°C.

[0059] [Comparative Example 5] Except for sowing in March, the same procedure as in Comparative Example 1 was carried out. The soil temperature until germination was 5±15°C.

[0060] Table 1 shows the results for Examples 1 to 6 and Comparative Examples 1 to 5. The seedling yield is the ratio of the number of seedlings (number of seedlings) that reached a seedling height of 30 cm or more and a base diameter of 3.5 mm or more after seedling raising to the number of seedlings (number of seedlings raised) transplanted into the container (the same applies below).

[0061] [Table 1]

[0062] In the comparative example, almost no seeds germinated after one month, whereas in the examples, most of the seeds germinated, reaching a value close to the prescribed germination rate of the sown seeds. As is clear from Table 1, in comparison with the comparative examples 1 to 5, in the examples 1 to 6, although the period from sowing to germination was one month, seedlings with an average seedling height of 30 cm or more and an average root diameter of 3.5 mm or more could be obtained after raising, exceeding the standard for container seedlings that can be transplanted from the mountains.

[0063] Furthermore, while the seedling yield rate in Comparative Examples 1 to 5 was 50% or less, in Examples 1 to 3 a high seedling yield rate of 80% or more was observed.

[0064] [Example 7] In December 2019, cypress seeds were sown in a seedling box covered with Akadama soil fine granules (Yanashima Shoji Co., Ltd.), and germinated by controlling the soil temperature in an artificial climate chamber to be within the range of 24 ± 2 ° C. The number of seeds sown, product information of the artificial climate chamber, temperature control method, and irrigation method were the same as in Example 1.

[0065] The seedlings that germinated after about one month (having a size similar to that of the seedlings in Example 1) were transplanted into a seedling container filled with a mixture of peat moss (Sun & Hope Co., Ltd.), Kanuma small grain soil (Akagi Engei Co., Ltd.), and Akadama small grain soil (Yanagishima Shoji Co., Ltd.) in a ratio of 4:1:1 (volume ratio), and placed in a vinyl greenhouse. During the seedling raising period, overhead irrigation was performed as appropriate, and Hyponex concentrate (Hyponex Japan Co., Ltd.) was sprayed once a week at a 500-2000-fold dilution. The seedling raising container used was the same as that used in Example 1.

[0066] Seedling height and base diameter were measured in November 2020. Container seedlings were deemed suitable for transplanting if the average was 30 cm or more and 3.5 mm or more, respectively.

[0067] [Example 8] After sowing, the same procedure as in Example 7 was carried out, except that the soil was managed in a germination chamber and the soil temperature was controlled to be 23±3°C.

[0068] [Example 9] After sowing, the cultivation soil was managed in the same manner as in Example 7, except that an agricultural electric horticultural mat (same as in Example 3) was placed under the seedling boxes in a vinyl greenhouse and the cultivation soil temperature was controlled to be 25±2°C.

[0069] [Example 10] The same procedure as in Example 7 was carried out, except that the sowing period was January, the transplanting period was February, and the soil temperature was controlled to be 22±2°C.

[0070] [Example 11] The same procedure as in Example 7 was carried out, except that the sowing period was February, the transplanting period was March, and the soil temperature was controlled to be 26±2°C.

[0071] [Example 12] The same procedure as in Example 7 was carried out, except that the sowing period was March, the transplanting period was April, and the soil temperature was controlled to be 28±2°C.

[0072] [Comparative Example 6] The same procedure as in Example 7 was carried out, except that the temperature of the culture soil was not controlled and the germinated hair seedlings were transplanted in May of the following year. The temperature of the culture soil until germination was 5±15° C.

[0073] [Comparative Example 7] Except for the fact that the temperature of the culture soil was not controlled and that the period from sowing to transplanting was controlled in a greenhouse, the same procedure as in Example 7 was carried out. The culture soil temperature until germination was 10±15°C.

[0074] [Comparative Example 8] Except for sowing in January, the same procedure as in Comparative Example 6 was carried out. The soil temperature until germination was 5±15°C.

[0075] [Comparative Example 9] Except for sowing in February, the same procedure as in Comparative Example 6 was carried out. The soil temperature until germination was 5±15°C.

[0076] [Comparative Example 10] Except for sowing in March, the same procedure as in Comparative Example 6 was carried out. The soil temperature until germination was 5±15°C.

[0077] Table 2 shows the results for Examples 7 to 12 and Comparative Examples 6 to 10.

[0078] [Table 2]

[0079] In the comparative example, almost no seeds germinated after one month, whereas in the examples, most of the seeds germinated, reaching a value close to the prescribed germination rate of the sown seeds. As is clear from Table 2, in comparison with the comparative examples 6 to 10, in the examples 7 to 12, although the period from sowing to germination was one month, the average seedling height after raising was 30 cm or more and the average root diameter was 3.5 mm or more, which was within the standard for container seedlings that can be transplanted from the mountains.

[0080] Furthermore, in Comparative Examples 6 to 10, the seedling yield rate was less than 50%, whereas in Examples 7 to 12, a high seedling yield rate of 70% or more was observed.

[0081] [Example 13] In December 2019, larch seeds were sown in a nursery box covered with fine Akadama soil (Yanagishima Shoji Co., Ltd.), and germinated by controlling the soil temperature in an artificial climate chamber to be within the range of 24 ± 2 ° C. The number of seeds sown, product information of the artificial climate chamber, temperature control method, and irrigation method were the same as in Example 1.

[0082] The seedlings that germinated after about one month (having a size similar to that of the seedlings in Example 1) were transplanted into a seedling container filled with a mixture of peat moss (Sun & Hope Co., Ltd.), Kanuma small grain soil (Akagi Engei Co., Ltd.), and Akadama small grain soil (Yanagishima Shoji Co., Ltd.) in a ratio of 4:1:1 (volume ratio), and placed in a vinyl greenhouse. During the seedling raising period, overhead irrigation was performed as appropriate, and Hyponex concentrate (Hyponex Japan Co., Ltd.) was sprayed once a week at a 500-2000-fold dilution. The seedling raising container used was the same as that used in Example 1.

[0083] Seedling height and base diameter were measured in November 2020. Container seedlings were deemed suitable for transplanting if the average was 30 cm or more and 3.5 mm or more, respectively.

[0084] [Example 14] After sowing, the same procedure as in Example 13 was carried out, except that the soil was managed in a germination chamber and the soil temperature was managed to be 23±3°C.

[0085] [Example 15] After sowing, the management of the soil was carried out in the same manner as in Example 13, except that an agricultural electric horticultural mat (same as in Example 3) was placed under the seedling boxes in a vinyl greenhouse and the soil temperature was controlled to be 25±2°C.

[0086] [Example 16] The same procedure as in Example 13 was carried out, except that the sowing period was January, the transplanting period was February, and the soil temperature was controlled to be 22±2°C.

[0087] [Example 17] The same procedure as in Example 13 was carried out, except that the sowing period was February, the transplanting period was March, and the soil temperature was controlled to be 26±2°C.

[0088] [Example 18] The same procedure as in Example 13 was carried out, except that the sowing period was March, the transplanting period was April, and the soil temperature was controlled to be 28±2°C.

[0089] [Comparative Example 11] The same procedure as in Example 13 was carried out, except that the temperature of the culture soil was not controlled and the germinated hair seedlings were transplanted in May of the following year. The temperature of the culture soil until germination was 5±15° C.

[0090] [Comparative Example 12] Except for the fact that the temperature of the culture soil was not regulated and that the period from sowing to transplanting was managed in a greenhouse, the same procedure as in Example 13 was carried out. The culture soil temperature until germination was 10±15°C.

[0091] [Comparative Example 13] Except for sowing in January, the same procedure as in Comparative Example 11 was carried out. The soil temperature until germination was 5±15°C.

[0092] [Comparative Example 14] Except for sowing in February, the same procedure as in Comparative Example 11 was carried out. The soil temperature until germination was 5±15°C.

[0093] [Comparative Example 15] Except for sowing in March, the same procedure as in Comparative Example 11 was carried out. The soil temperature until germination was 5±15°C.

[0094] Table 3 shows the results for Examples 13 to 18 and Comparative Examples 11 to 15.

[0095] [Table 3]

[0096] In the comparative example, almost no seeds germinated after one month, whereas in the examples, most of the seeds germinated, reaching a value close to the prescribed germination rate of the sown seeds. As is clear from Table 3, in comparison with the comparative examples 11 to 15, in the examples 13 to 18, although the period from sowing to germination was one month, the average seedling height was 30 cm or more and the average root diameter was 3.5 mm or more after raising, exceeding the standard for container seedlings that can be transplanted from the mountains.

[0097] Furthermore, in Comparative Examples 11 to 15, the seedling yield rate was less than 50%, whereas in Examples 13 to 18, a high seedling yield rate of 70% or more was observed.

[0098] These results show that according to the present invention, seedlings with stable quality can be produced efficiently in a short period of time by controlling the temperature in a predetermined manner after sowing.

Claims

1. The method for producing seedlings includes a germination step of sowing seeds of a woody plant in culture soil, adjusting the temperature of the culture soil so that the average culture soil temperature is 20 to 30°C and the fluctuation range between the culture soil temperature and the average culture soil temperature is ±5°C, and obtaining germinated hair seedlings.

2. 2. The method according to claim 1, wherein the germination step is carried out during a period when the monthly mean temperature is below 20°C or during the period from October to April.

3. The method according to claim 1 or 2, wherein the duration of the germination step is 20 to 50 days from sowing.

4. The method according to any one of claims 1 to 3, wherein the temperature is adjusted so that the fluctuation range from the average soil temperature is within ±3 ° C.

5. The method according to any one of claims 1 to 4, wherein the temperature of the culture soil is adjusted by at least one of an artificial weather machine, a germination chamber, or a horticultural heat-retaining mat.

6. The method for producing seedlings according to any one of claims 1 to 5, further comprising a seedling raising step of raising the seedlings obtained in the germination step to obtain seedlings suitable for planting.

7. The method for producing seedlings according to any one of claims 1 to 6, wherein the germinated seedlings are transplanted into a seedling raising pot and then a seedling raising step is carried out.

8. 8. The method for producing seedlings according to claim 7, wherein the duration of the seedling raising step is 11 months or less.

9. A method for producing a plantation forest, comprising producing seedlings by the method for producing seedlings according to any one of claims 1 to 8, and planting the seedlings in the plantation forest.

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