JP7195474B1 - How to grow kale - Google Patents

Abstract

[Problem] To provide a method for cultivating kale, which has a large weight per kale strain, a large yield per cultivation area, and a large amount of nutrients. A method for cultivating kale by irradiating the kale seedlings with light while leaving a gap between adjacent kale seedlings. A method of cultivating kale has a cultivation cycle comprising a light period and a dark period darker than the light period, the dark period being lower in temperature than the light period, the light being white light, and the growth of the kale seedlings. The ratio of the light photon flux density (μmol/(m2s)) to the interval (mm) is 2.0 to 7.0. [Selection drawing] Fig. 2

Description

The present invention relates to a method for cultivating kale with increased yield and adjusted nutrients.

Kale is a cruciferous vegetable that is close to the original species of cabbage, and is known as a vegetable with high nutritional value. Therefore, various cultivation methods have been proposed for kale.

For example, Patent Document 1 includes a step (a) of irradiating the kale with red light from a light source and a step (b) of irradiating the kale with blue light from the light source, and the irradiation time of each step is independent and uniform. A method of cultivating kale has been proposed in which each step is performed alternately for 3 hours or more and less than 48 hours.
Patent Document ^{1 describes adjusting the kale density to 25 to 100 strains/m 2 .} It also describes that the photosynthetic photon flux densities of the irradiated red light and blue light are 30 to 400 μmol/(m ² s), respectively.
In addition, 28 strains (strain density: 36.5 strains/m ² ) were planted at intervals of 15 cm, red light was applied continuously for 12 hours at 200 μmol/(m ² s), and blue light was applied at 70 μmol/(m ² ). It is also described that the continuous irradiation time was set to 12 hours in s).

WO2020/067266

Currently, there is a demand for the cultivation of kale that the weight per kale obtained is heavy and the yield per cultivation area is large. In addition, high demands are placed on the nutrients of the harvested kale.
However, in the cultivation method of cultivating kale by alternately irradiating red light and blue light in Patent Document 1, the weight of each kale strain is heavy, and the yield per cultivation area cannot be increased. Furthermore, the nutrients of the harvested kale cannot be increased.
An object of the present invention is to provide a method for cultivating kale, which has a large weight per kale strain, a large yield per cultivation area, and a large amount of nutrients.

In order to achieve the above object, the invention [1] is a kale cultivation method in which the kale seedlings are cultivated by irradiating the kale seedlings with light at intervals between adjacent kale seedlings. with a cultivation cycle comprising a light period and a dark period darker than the light period, the dark period being lower in temperature than the light period, the light being white light, and the distance between the kale seedlings (mm ) to the light photon flux density (μmol/(m ² s)) is 2.0 to 7.0.
The invention [2] is the cultivation of kale according to the invention [1], wherein the cultivation method is a hydroponic system, a nutrient solution is used when cultivating by the hydroponic system, and the concentration of the nutrient solution is kept constant. The method.
Invention [3] is the method for cultivating kale according to Invention [1] or [2], wherein the interval is less than 75 mm.
Invention [4] is the method for cultivating kale according to any one of Inventions [1] to [3], wherein the ratio is 3.0 to 7.0.
Invention [5] is the method for cultivating kale according to any one of inventions [1] to [4], wherein the light is artificial light.
Invention [6] is the method for cultivating kale according to any one of inventions [1] to [5], wherein the kale seedling density is 170 to 2500 (strain/m ² ).

ADVANTAGE OF THE INVENTION According to this invention, the weight per one kale strain is heavy, the yield per cultivation area is large, and the cultivation method of the kale with many nutrients can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view which shows an example of the cultivation container used for the cultivation method of the kale of embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic side view which shows an example of the cultivation container used for the cultivation method of the kale of embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is typical sectional drawing which shows an example of the cultivation container used for the cultivation method of the kale of embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION The method for cultivating kale of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.
It should be noted that the embodiments and illustrated contents described below are examples for describing the present invention, and the present invention is not limited to the drawings shown below.
(Kale)
Kale broadly refers to plants classified as Brassica oleracea L var.acephala or Brassica oleracea L convar.acephala, or plants having these plants as one parent. Specific varieties classified into kale include, for example, Juicy Green (variety registration No. 12578) and Sweet Green (variety registration No. 17702) as Brassica oleracea L co nvar.acephala (DC) Alef.var.sabellicaL. No.), Samba Carnival (Variety Registration No. 17704), Kitchen (Red) (Variety Unregistered), Kitchen (Green) (Variety Registration No. 17703), Gozilana (Carbolo Leaf Green) (Variety Registration No. 17701), etc.; Brassica oleracea L convar. acephala (DC) Alef. var. Among the cultivars specifically exemplified, samba carnival is particularly preferred.
Kale also includes habotan (flower kale) and habotan species.
Kale also includes Aletta (variety registration No. 20556) and Petit Vert (registered trademark) crossed with kale. Kale also includes various kale hybrids.

(kale seedlings)
Kale seedlings refer to seedlings of kale raised for the purpose of future transplantation, that is, planting.
The kale seedlings to be used for fixed planting are not particularly limited, and are preferably seedlings having one or more true leaves and eight or less true leaves, and one or more true leaves. More preferably, it is a seedling that has developed within the range of 4 or less, more preferably a seedling that has developed within the range of 1 or more and 3 or less true leaves, and 1 true leaf. As mentioned above, it is particularly preferable that the seedling is developed within the range of two sheets or less.
Kale seedlings also include those in the stage just before harvesting. For kale seedlings, the light photon flux density (μmol/(m ² Kale seedlings grown under conditions where the ratio of s)) is 2.0 to 7.0 are also included in kale seedlings. Furthermore, the sowing (seeding) interval, that is, the interval between kale seedlings P, is less than 75 mm, and the sowing (seeding) density, that is, the kale seedling strain density is 170 to 2,500 strains/m ² . things are also included.

[Kale cultivation method]
A method for cultivating kale will be described below.
The method of cultivating kale is a method of cultivating kale seedlings by irradiating the kale seedlings with light at intervals between adjacent kale seedlings. A method of growing kale has a cultivation cycle comprising a light period and a dark period darker than the light period, wherein the dark period is lower in temperature than the light period, the light is white light, and the kale seedling spacing is The ratio of photon flux density of light (μmol/(m ² s)) to (mm) is 2.0 to 7.0. As a result, the weight of each kale strain is high, the yield per cultivation area is large, and nutrients can be increased.

As used herein, the term “photoperiod” means a continuous period during which plants are placed under light intensity conditions that allow photosynthesis. Here, as an example of the light intensity condition that allows photosynthesis, the light intensity (photon flux density of photosynthesis) is in the range of about 100 to 1500 μmol/(m ² s).
The term "dark period" means a period corresponding to the night under natural conditions, and in this specification means a period other than the light period. Specifically, the "dark period" is usually a continuous period in which the plant is placed under the condition of a light intensity of 0 μmol/(m ² s). Considering the influence of , etc., a continuous period in which the plant is placed under the condition of a light intensity of 5 μmol/(m ² s) or less can be exemplified as a “dark period”.
A "cultivation cycle" means that the above-described repeating unit is repeated with one continuous light period and one continuous dark period as a repeating unit.
In addition, the total of one continuous light period and one continuous dark period is 24 hours unless otherwise specified in this specification. In this case the repeating unit is 24 hours. For example, out of 24 hours, the light period is 16 hours and the dark period is 8 hours. 24 hours correspond to one day.

Here, FIG. 1 is a schematic plan view showing an example of a cultivation container used in the kale cultivation method of the embodiment of the present invention, and FIG. 2 is a cultivation container used in the kale cultivation method of the embodiment of the present invention. 2 is a schematic side view showing an example of .
Kale is cultivated, for example, by a hydroponics method using a cultivation container 10 shown in FIG.
A plurality of kale seedlings P are arranged on the surface 11 of the cultivation container 10 shown in FIG. In FIG. 1, for example, a total of 25 kale seedlings P are arranged. In addition, the cultivation container 10 is also called a panel. For example, the shape of the surface 11 of the cultivation container 10 is a square.
The kale seedlings P are arranged at equal intervals in the X direction and the Y direction which are orthogonal to each other, and the kale seedlings P are arranged so as to be positioned at the vertices of a square when the panel surface is divided into a rectangular lattice. there is In FIG. 1, the kale seedlings P have the same spacing Dx in the X direction and Dy in the Y direction. Regarding the interval between the kale seedlings P, when the intervals Dx and Dy are different, the smallest interval among these intervals is taken as the interval between the kale seedlings P.
The interval between the kale seedlings P is the distance between the main axes of adjacent kale seedlings P at the ground level.

Of the intervals Dx and Dy, which are the intervals between the kale seedlings P, it is preferable that either one is less than 75 mm, and more preferably the interval Dx or the interval Dy is less than 75 mm.
If the interval (between plants) between the kale seedlings P is widened, the weight of each plant becomes heavy, but since the number of plants per panel (cultivation container 10) is reduced, the entire plant in one panel (cultivation container 10) is reduced. lighter weight. That is, the yield per cultivation area of kale is reduced, resulting in low productivity.
Conversely, if the interval between the kale seedlings P is narrowed, the weight of each kale strain is reduced, but the total weight of kale per panel is increased. That is, the yield per cultivation area of kale increases, and productivity increases. Therefore, it is preferable that the interval between the kale seedlings P is less than 75 mm.
If the spacing between kale seedlings is too narrow, the proportion of the stems in the grown kale will increase, resulting in poor appearance and poor marketability. Therefore, the lower limit of the spacing between kale seedlings is preferably 20 mm. The distance between kale seedlings is more preferably 30 mm to 70 mm.

Also, the kale seedling density is preferably 170 to 2500 plants/m ² . If the density of kale seedlings is 200 to 1100 strains/m ² , the weight of each strain is high and the productivity per panel is maintained. The kale seedling stock density represents the placement density of the kale seedlings.
The stock density of kale can be calculated by, for example, the formula "stock density=number of strains on cultivation surface/area of cultivation surface". As used herein, a growing surface means the smallest square or rectangular area on the surface 11 of the growing container 10 on which the kale seedlings are placed that can contain all of the kale seedlings.

As shown in FIG. 2 , a light source 20 that emits white light is arranged above the surface 11 of the cultivation container 10 .
The ratio of the light photon flux density (μmol/(m ² s)) to the distance between the kale seedlings (mm) is 2.0 to 7.0. That is, the photon flux density (μmol/(m ² s))/interval between kale seedlings (mm) is 2.0 to 7.0. The ratio of the light photon flux density (μmol/(m ² s)) to the distance between kale seedlings (mm) is preferably 3.0 to 7.0. As a result, the weight per kale strain can be increased, the yield per cultivation area can be increased, and nutrients such as the amount of vitamin C and the Brix value can be increased.
If the ratio of the light photon flux density (μmol/(m ² s)) to the interval (mm) between the kale seedlings is less than 2.0, the weight per kale strain increases, but the weight per cultivation area increases. Kale yields are reduced. In addition, although the photon flux density per seedling (1 plant) of kale is high, the amount of vitamin C is low, the Brix value is low, and the amount of nitrate ions is high.
When the ratio of the photon flux density of light (μmol/(m ² s)) to the interval (mm) between kale seedlings exceeds 7.0, the total weight of kale per cultivation area is heavy, but one kale strain Light weight per hit. In addition, the photon flux density per seedling (1 plant) of kale is low, the amount of vitamin C is low, the Brix value is low, and the amount of nitrate ions is high.

The white light with which the kale seedlings are irradiated is not particularly limited, and may be natural light such as sunlight or artificial light. For example, the photosynthetic photon flux density of sunlight is 1000 μmol/(m ² s) or more, while that of artificial light is about 100 to 500 μmol/(m ² s).
The light source 20 is, for example, an inorganic or organic LED (Light Emitting Diode), or a semiconductor light emitting element such as a laser, a discharge tube such as a fluorescent lamp, a mercury lamp, a rare gas lamp, an electrodeless lamp, a filament light emitting device such as an incandescent lamp, Devices are available that emit white light, such as by energy transitions such as radiant light or fluorescence. Note that the light source 20 may be configured to have a mechanism for changing the irradiation range. When a white LED other than sunlight is used for the light source 20, the white light is artificial light.

As described above, the cultivation method has a cultivation cycle comprising a light period and a dark period that is darker than the light period.
With artificial light, a highly efficient LED is used as a light source for illumination, but the irradiation time per day is extended in order to irradiate a large amount of light energy.
The average irradiation time/day of the sun is 12 hours/day throughout the year, but in a plant factory with artificial light, it is irradiated for about 16 to 20 hours, and 24 hours irradiation is also possible, but the period during which no light is irradiated, that is, If there is no night (dark period), the morphology of the kale crop will change, and defects such as defects will occur in the kale.
Here, the integrated light energy of artificial light is considerably lower than that of sunlight. However, since artificial light has a low integrated light energy, it also has the advantage of being soft and having a good texture. Therefore, in the case of artificial light, the irradiation time is preferably 8 to 23 hours/day, more preferably 16 hours.

Between the period when light is irradiated (light period) and the period when light is not irradiated (dark period), the temperature during the period when light is not irradiated (dark period) is lower than the temperature of the light period). This increases the nutrients in the harvested kale, such as vitamin C, and also increases the Brix value. In this way, nutrient-rich kale can be obtained.
Vitamin C is an antioxidant. By making the temperature in the dark period lower than the temperature in the light period when light is irradiated, stress is applied in the dark period, which is thought to increase vitamin C.

The Brix value represents the sugar content. The value of Brix is a value obtained by converting the refractive index of the granulation liquid measured at room temperature using a sugar refractometer to mass/mass% of a pure sucrose solution at 20° C. using a temperature correction table. . Brix values are measured using a Brix meter.
As described above, it is thought that by making the temperature in the dark period lower than the temperature in the light period when light is applied, sugar consumption in the dark period is reduced and the Brix value is increased.
In addition, the absorption of fertilizer (nutrient solution) is reduced due to stress as described above. This suppresses an increase in nitrate ion content in the harvested kale. Nitrate ions produce a "bitter" or "harsh" taste. If the content of nitrate ions is high, it becomes easy to feel "bitterness" or "harshness" strongly.

The temperature in the dark period is lower than that in the light period, and that the temperature in the dark period is lower than that in the light period means that the temperature difference between the light period and the dark period is 2°C or more. The temperature difference between the light period and the dark period is more preferably 3° C. or higher, even more preferably 4° C. or higher, and most preferably 5° C. or higher from the viewpoint of increasing nutrients. Also, the upper limit of the temperature difference between the light period and the dark period is not particularly limited, but is, for example, 20°C.
The temperature in the dark period and the temperature in the light period are indoor temperatures in the case of indoor cultivation. In the case of alley cultivation, it is the outside temperature. Both can be measured with a thermometer.
As a method of making the temperature lower in the dark period than in the light period, for example, lowering the set temperature of the air conditioning in the cultivation room can be mentioned.

The arrangement pattern of kale seedlings P is not limited to the square shown in FIG. When the intervals between the kale seedlings P differ depending on the direction, the smallest interval among the intervals is taken as the interval between the kale seedlings P.

[Example of cultivation container]
The cultivation container 10 is used for cultivation of kale seedlings P by a hydroponics method. Specifically, a nutrient solution L (liquid fertilizer) containing nutrients necessary for growing kale seedlings P is stored inside the cultivation container 10 shown in FIG.
The kale seedlings P are placed and held in the cultivation container 10 in a state in which the roots of the kale seedlings P are soaked in the nutrient solution L in the cultivation container 10 . That is, the kale seedlings P are permanently planted in the cultivation container 10 and then grown in the cultivation container 10 until they are harvested. The interval between the kale seedlings P is the interval when the kale seedlings P are permanently planted in the cultivation container 10 . Although only one kale seedling P is shown in FIG. 3, a total of 25 kale seedlings P are arranged at intervals in the cultivation container 10 as shown in FIG.

The nutrient solution L is prepared by adding and dissolving various nutrients in a solvent such as water, and adjusting the concentration of each component according to the type of plant to be grown. Components in the nutrient solution L include nitrogen (specifically, ammonia nitrogen or nitrate nitrogen), phosphoric acid (P ₂ O ₅ ), potassium (K ₂ O), lime (CaO), magnesium ( MgO), manganese (MnO), boron ₍ B2O3) _, iron (Fe), copper (Cu), zinc (Zn) and molybdenum (Mo).

As shown in FIG. 3, the roots of the kale seedling P are immersed in the nutrient solution L in the cultivation container 10, and the leaf-stem portion of the kale seedling P is exposed to the outside of the cultivation container 10. It is grown in the cultivation container 10 . Hereinafter, the period during which the kale seedlings P are grown in the cultivation container 10 while the roots of the kale seedlings P are soaked in the nutrient solution L in the cultivation container 10 is the kale seedling growing period.
During the growing period of the kale seedlings P, the cultivation container 10 in which the kale seedlings P are arranged may be rotated or oscillated by a driving device (not shown). As a result, a flow occurs in the nutrient solution L in the cultivation container 10 and the nutrient solution L is agitated, so that a decrease in the concentration of the nutrient solution around the roots in the cultivation container can be suppressed. can properly absorb the nutrients in the nutrient solution L from the roots, so that the kale seedlings P can be grown well.
In kale cultivation, it is preferable to control the concentration of the nutrient solution to be constant. The control of the concentration of the nutrient solution will be explained later.

The cultivation container 10 is, for example, a substantially box-shaped cultivation container as shown in FIG. 3, and has a bottom wall 10a, side walls 10b and a ceiling wall 10c. The surface of the ceiling wall 10 c is the surface 11 of the cultivation container 10 . The interior of the cultivation container 10 is a closed space surrounded by these walls. A predetermined amount of nutrient solution L is stored in this closed space, and strictly speaking, it stays in the cultivation container 10 . Here, that the nutrient solution L stays in the cultivation container 10 means that the nutrient solution L is kept in the cultivation container 10 without being circulated. It should be noted that the part of the nutrient solution L in the cultivation container 10 that is absorbed by the kale seedlings P and the part that naturally evaporates from the cultivation container 10 are allowed.
As described above, since the space in which the nutrient solution L is stored in the cultivation container 10 is a closed space, the generation of algae due to the irradiation of the nutrient solution L with light can be suppressed satisfactorily.

A rectangular opening 12 is provided at the top of the cultivation container 10 as shown in FIG. The opening 12 is positioned at the upper end of a through hole drilled in the ceiling wall 10c, and communicates the internal space of the cultivation container 10 with the outside of the cultivation container 10, ie, the atmosphere. Although only one opening 12 is shown in FIG. 3 , a plurality of openings 12 are provided in the cultivation container 10 .

The shape of the cultivation container 10 is not limited to the shape shown in FIG. 3, and may be, for example, a bottle shape like a flask. Although the size of the cultivation container 10 is not particularly limited, it is preferably a size that can be transported. The structure of the cultivation container 10 is not particularly limited, either. Also, the shape and number of the openings 12 are not particularly limited, and the openings 12 may be circular.

The material of the cultivation container 10 is also not particularly limited, but is made of a material having a visible light transmittance of 10% or less for the purpose of suppressing the growth of algae due to light irradiation of the nutrient solution L. It is preferable to grow the seedlings P of kale using the cultivation container 10 .
Examples of materials for the cultivation container 10 include polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile-styrene resin (AS), acrylonitrile-butadiene-styrene resin (ABS), polyvinyl chloride (PVC), Plastics such as methacrylic resin (PMMA) and polyethylene terephthalate (PET) are preferred.
Transmittance can be measured by a known measurement method, for example, a measurement method using a spectrophotometer with an integrating sphere. The transmittance can be measured by making the light enter the integrating sphere through the aperture and detecting the light traveling straight or scattered within the sphere.

The surface color of the cultivation container 10 is not particularly limited, either. Colors with relatively high light reflectivity are preferred. In addition, when priority is given to lowering the transmittance, the surface color of the cultivation container 10 is preferably black, blue, red, green, yellow, or the like. is preferably processed to absorb the

The above-mentioned opening 12 is provided in the upper part of the cultivation container 10 , and the roots of the kale seedlings P enter the inside of the cultivation container 10 through the opening 12 and are immersed in the nutrient solution L in the cultivation container 10 . The leaf and stem portion of the kale seedling P is exposed outside the cultivation container 10 through the opening 12 .

More specifically, the kale seedling P is held by a medium 14 made of urethane, rock wool, sponge, or the like. The culture medium 14 corresponds to a holding member and holds the kale seedlings P. The culture medium 14 is accommodated in a cup portion 16 made of a small bowl-shaped film body. A relatively large hole is formed in the bottom of the cup portion 16 to expose the lower surface of the culture medium 14 . The roots of the kale seedling P extend protruding from the exposed underside of the medium 14 as shown in FIG. On the other hand, the base of the stem (the part near the root) of the kale seedling P is buried in the culture medium 14, and above the upper surface of the culture medium 14, the leaf-stem portion of the kale seedling P is expanded. The kale seedling P is held in the culture medium 14 in such a state.

The cup portion 16 is fitted into the opening 12 of the cultivation container 10 from above as shown in FIG. Thereby, the culture medium 14 accommodated in the cup portion 16 is attached to the cultivation container 10 . In this state, the lower end of the medium 14 is positioned below the liquid surface of the nutrient solution L in the cultivation container 10, and the roots of the kale seedlings P protruding from the lower surface of the medium 14 are inside the cultivation container 10. The nutrient solution L is soaked. In addition, the leaf and stem portion of the kale seedling P, which is above the upper surface of the culture medium 14, protrudes from the opening 12 to the outside of the cultivation container 10. - 特許庁

In the cultivation container 10, as shown in FIG. 1, a plurality of kale seedlings P are arranged at intervals.
As shown in FIG. 3, in the cultivation container 10, one cup portion 16 is used for growing one kale seedling P. As shown in FIG. Here, the “individual” is a unit representing the number of kale seedlings P, and one individual corresponds to one kale seedling P strain. The number of kale seedlings P cultivated using one cup portion 16 may be one, or two or more. Even if there are two or more kale seedlings P in one cup portion 16, they are treated as one seedling in the present invention.

<Cultivation conditions, etc.>
In the hydroponics method, the temperature of the nutrient solution supplied to the cultivation container 10 is preferably 10° C. or higher and 30° C. or lower, preferably 18° C. or higher and 28° C. or lower, and more preferably 20° C. or higher and 23° C. or lower. If the liquid temperature is within the above range, it is possible to prevent nutrient absorption by the roots of plants from being disturbed and the growth to be greatly deteriorated.
The concentration of the nutrient solution is generally controlled by controlling the electric conductivity (EC) of the nutrient solution, and the electric conductivity of the nutrient solution is used as a measure of the concentration of the nutrient solution. If the electrical conductivity (EC) of the nutrient solution is too high, it may cause morphological abnormalities due to excess nutrition and a decrease in the amount of growth due to osmotic pressure stress in the root zone. The electrical conductivity (EC) of the nutrient solution is preferably 1.3 dS/m or more and 2.8 dS/m or less, more preferably 1.5 dS/m or more and 2.0 dS/m or less. In addition, from the viewpoint of promoting the growth of kale, it is preferable to cultivate the solution at a pH of 5.5 or more and 6.5 or less.
As a method of controlling the electrical conductivity of the nutrient solution, for example, the electrical conductivity (EC) of the nutrient solution is measured, and if the measured value is 0.1 less than the target value of the electrical conductivity (EC), a nutrient with a high concentration is used. Liquid (liquid fertilizer) was added until the target value was reached, and when the measured value exceeded the target value of electrical conductivity (EC) by 0.1, water was added until the target value was reached.

When the hydroponic cultivation method is performed indoors such as a greenhouse, the indoor temperature is the temperature at which the hydroponic cultivation method of general plants is performed, preferably 10 ° C. or higher and 30 ° C. or lower, and 15 ° C. or higher and 25 ° C. or lower. More preferably, the temperature is 20° C. or higher and 23° C. or lower.
The indoor relative humidity is the relative humidity for general hydroponic cultivation of plants, preferably 40% to 90%, more preferably 50% to 80%, and even more preferably 65% to 75%.

The relative humidity in the plant community is preferably adjusted to 65% or more and 75% or less as described above when the plant community is not densely planted. On the other hand, as the plants grow, they become densely planted and the relative humidity in the plant community becomes extremely high. Therefore, the relative humidity in the plant community is preferably maintained at 50% or more and 95% or less, more preferably 60% or more and 80% or less, and even more preferably 65% or more and 75% or less.

Increasing the carbon dioxide concentration is also preferably used to promote plant growth. Carbon dioxide concentration is preferably 400 volume ppm or more and 1600 volume ppm or less from the viewpoint of economic efficiency and favorable effect on growth. It is more preferably 600 volume ppm or more and 1400 volume ppm or less, and still more preferably 700 volume ppm or more and 1300 volume ppm or less. If it is too low, it may cause a decrease in growth due to malnutrition.
The method for cultivating kale is not limited to the hydroponic cultivation method described above, and other cultivation methods such as alley cultivation may be used. In order to control the concentration of the nutrient solution as described above, hydroponic cultivation is preferred.
Moreover, as a cultivation condition, as described above, a cultivation cycle having a light period and a dark period darker than the light period is provided, and the temperature in the dark period is lower than that in the light period.

The present invention is basically configured as described above. Although the method for cultivating kale of the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

The features of the present invention will be described more specifically with reference to examples below. The materials, reagents, amounts and ratios of substances, operations, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Accordingly, the scope of the invention is not limited to the following examples.

Hereinafter, the method for cultivating kale of the present invention will be described more specifically.
Green kale seedlings raised under the following conditions were irradiated with light and cultivated by a hydroponics method.
Green kale (Nakahara Seed Co., Ltd.) seeds were sown in a commercially available urethane sponge for hydroponics, one seed per hole, and after dark treatment for 1 day, under a white fluorescent light with a light intensity of 140 μmol/(m ² s). Seedlings were raised for 15 days from seeding under 16 hours/day of sunshine. The nutrient solution was sprinkled with water from the 3rd day after sowing, and from the 7th day after sowing, EC = 1.5 dS / m, pH = 6 prepared from Otsuka A formula (cultivation nutrient solution for leafy vegetables, OAT Agrio Co., Ltd.). 0.0.

[Example 1]
Seedlings of green kale (Nakahara Seed Co., Ltd.) raised for 15 days from sowing by the above method were planted in a cultivation container (panel) and cultivated for 31 days after sowing (16 days after planting).
The panel size was 1200 mm×600 mm.
Cultivation was carried out indoors, with a light period temperature of 22° C., a dark period temperature of 17° C., a relative humidity of 70%, and a carbon dioxide gas concentration of 1000 ppm by volume. In addition, the nutrient solution was controlled by a nutrient solution circulator, EC = 1.5 dS/m, pH = 6.0, nutrient solution temperature was set at 22°C, and 72 strains were planted at intervals of 94 mm between kale seedlings. In this case, the kale seedling density is 100 plants/m ² .
When the panel size is 1200 mm×600 mm and the plant interval is 94 mm as described above, (1200/94)=12 (rounded down) and (600/94)=6 (rounded down). 12×6/(1/(1.2×0.6))=100 plants/m ² .
After planting, light irradiation was performed under the following conditions.
As a light source, PGL-NE-200NWB manufactured by Ryoden Corporation was used as a white light source (artificial light).
The photon flux density of light was set to 250 μmol/(m ² s). The photon flux density was measured using a photon meter LI-250A manufactured by LI-COR.
As for the cultivation cycle, one cycle was 24 hours, the light period was 18 hours, and the dark period was 8 hours.

In Example 1, the kale that reached the harvest size on the 16th day after planting was harvested, and the total weight of the kale per panel was measured. Also, the total weight of kale per panel was divided by the number of kale strains in one panel to obtain the weight of kale per stalk.
In addition, in Example 1, the content of vitamin C in the harvested kale was determined. The content of vitamin C in the harvested kale was measured using RQflex (manufactured by Merck Ltd.).
Also, in Example 1, the Brix value of the harvested kale was determined. The Brix value of the harvested kale was measured using a Brix meter.
In addition, in Example 1, the content of nitrate ions in the harvested kale was determined. Nitrate ions produce a "bitter" or "harsh" taste as described above. The content of nitrate ions in the harvested kale was measured using RQflex (manufactured by Merck Ltd.).

[Example 2]
Example 2 was the same as Example 1 except that the interval between kale seedlings was changed to 64 mm. In Example 2, the kale seedling density is 225 plants/m ² .
When the panel size is 1200 mm×600 mm and the plant interval is 64 mm as described above, (1200/64)=18 (rounded down) and (600/64)=9 (rounded down). 18×9/(1/(1.2×0.6))=225 plants/m ² .
[Example 3]
Example 3 was the same as Example 1 except that the photon flux density was 150 μmol/(m ² s) and the interval between kale seedlings was 64 mm. In Example 3, the kale seedling density is 225 plants/m ² .
[Example 4]
Example 4 was the same as Example 2, except that the concentration of the nutrient solution was not controlled. In Example 4, the kale seedling density is 225 plants/m ² .
In Example 4, the nutrient solution was not controlled by the nutrient solution circulator, and the kale was cultivated with the nutrient solution at the beginning of cultivation.

[Comparative Example 1]
Comparative Example 1 was the same as Example 1, except that the interval between kale seedlings was changed to 150 mm. In Comparative Example 1, the kale seedling density was 44 strains/m ² .
In addition, when the panel size is 1200 mm x 600 mm and the strain interval is 150 mm as described above, (1200/94) x (600/94) x (1/(1.2 x 0.6)) = 44 strains/ m ² (rounded down).
[Comparative Example 2]
Comparative Example 2 was the same as Comparative Example 1 except that the distance between the kale seedlings was changed to 20 mm. In Comparative Example 2, the kale seedling density is 2500 plants/m ² .
In addition, when the panel size is 1200 mm×600 mm and the interval between plants is 20 mm as described above, (1200/20) 60, (600/20)=30. 60×30/(1/(1.2×0.6))=2500 plants/m ² .
[Comparative Example 3]
Comparative Example 3 was the same as Comparative Example 1 except that the photon flux density was changed to 150 μmol/(m ² s). In Comparative Example 3, the kale seedling density is 44 strains/m ² .

[Comparative Example 4]
Comparative Example 4 was the same as Comparative Example 1 except that the photon flux density was 150 μmol/(m ² s) and the distance between kale seedlings was 94 mm. In Comparative Example 4, the kale seedling density is 100 strains/m ² .
[Comparative Example 5]
Comparative Example 5 was the same as Comparative Example 1 except that the photon flux density was 150 μmol/(m ² s) and the distance between kale seedlings was 20 mm. In Comparative Example 5, the kale seedling density is 2500 strains/m ² .

[Comparative Example 6]
Comparative Example 6 was the same as Example 2 except that the temperature in the dark period was set to 22° C., which was the same as the temperature in the light period. In Comparative Example 6, the interval between kale seedlings was 64 mm, and the kale seedling density was 225 strains/m ² .
[Comparative Example 7]
Comparative Example 7 was the same as Example 3, except that the temperature in the dark period was 22° C., the same as the temperature in the light period. In Comparative Example 7, the interval between kale seedlings was 64 mm, and the kale seedling density was 225 strains/m ² .

In Examples 1 to 4 shown in Table 1, the ratio of the light photon flux density (μmol/(m ² s)) to the distance between kale seedlings (mm) satisfies 2.0 to 7.0. As a result, the total weight of kale per panel was increased, that is, the yield per cultivation area was high, and the weight per kale plant was also heavy. In addition, in Examples 1 to 4, the harvested kale had a higher vitamin C content, a higher Brix value, and a lower nitrate ion content than in Comparative Examples 1 to 7. From this, in Examples 1 to 4, kale with a large amount of nutrients could be cultivated.
In Comparative Examples 1, 3 and 4, the ratio of the light photon flux density (μmol/(m ² s)) to the distance between kale seedlings (mm) is less than 2.0. The weight per plant of kale was heavy, but the total weight of kale per panel was light. That is, the yield per cultivation area was small.
In Comparative Examples 2 and 5, the ratio of the light photon flux density (μmol/(m ² s)) to the distance between kale seedlings (mm) exceeds 7.0. The total weight of kale per panel was heavy, but the weight per kale plant was light.
In Comparative Examples 6 and 7, the temperature in the dark period is the same as the temperature in the light period, so compared to Comparative Examples 6 and 2, Comparative Example 7 compared to Example 3 content was low, the Brix value was low, and the content of nitrate ions was high.
In Comparative Examples 1 to 7, if the interval (mm) between the kale seedlings is the same, the darker (light photon flux density (μmol/(m ² s))) is lower, the Brix value is lower. tended to be.

REFERENCE SIGNS LIST 10 cultivation container 10a bottom wall 10b side wall 10c ceiling wall 11 surface 12 opening 14 culture medium 16 cup part 20 light source Dx, Dy interval L nutrient solution P seedling

Claims (5)

A method for cultivating kale, wherein the kale seedlings are cultivated by irradiating the kale seedlings with light at intervals between adjacent kale seedlings,
a cultivation cycle comprising a light period and a dark period darker than the light period, wherein the dark period is lower in temperature than the light period;
the light is white light,
The ratio of the photon flux density (μmol/(m ² s)) of the light to the distance (mm) between the kale seedlings is 2.0 to 7.0,
The intervals are equal intervals of 20 mm or more and less than 75 mm,
the photon flux density (μmol/(m ² s)) of the light is 150 to 250;
A method for cultivating kale, wherein the cultivation method is a hydroponics system, a nutrient solution is used when cultivating by the hydroponic system, and the concentration of the nutrient solution is kept constant. The method for cultivating kale according to claim 1, wherein the ratio is 2.0 to 3.9 . The method for cultivating kale according to claim 1, wherein the ratio is 3.0 to 7.0. The method for cultivating kale according to any one of claims 1 to 3, wherein the light is artificial light. The method for cultivating kale according to any one of claims 1 to 3, wherein the seedling density of the kale is 170 to 2500 (strain/m ² ).

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