Method for cultivating everbearing strawberries and facility for cultivating everbearing strawberries

Abstract

To provide a method for cultivating everbearing strawberries, capable of harvesting a large amount of strawberry fruits in September and October and suppressing the running cost of a cooling apparatus.SOLUTION: The method for cultivating everbearing strawberries comprises: setting seedlings 3 of everbearing strawberries in a culture medium in a cultivation facility 1 composed of a vinyl house or a glass house in early May or June; shielding heat from the outside of the cultivation facility 1 by a heat-shielding agent applied to an upper surface of a roof 4a of the cultivation facility 1 in at least a part of a period from July to August; and in at least a part of the period from July to August, the temperature rise of the air in the cultivation facility 1 is suppressed by operating a fine mist cooling device 5a and a circulating fan 5b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for cultivating everbearing strawberries that enables a large harvest of strawberry pseudofruits (hereinafter referred to as "fruits" for convenience) in September and October, and a cultivation facility for everbearing strawberries. [Background technology]

[0002] Traditionally, seasonal strawberries have been widely cultivated from November to May of the following year, with many strawberries harvested from winter through spring.

[0003] On the other hand, seasonal strawberries have the property that flower buds do not differentiate if the hours of sunlight are long. Therefore, in order to harvest seasonal strawberries in the fall, it is necessary to shorten the hours of sunlight during the long summer months (July to August; the same applies below).

[0004] In contrast, everbearing strawberries are able to induce flower bud differentiation without controlling the hours of daylight, even during the long summer days.

[0005] For example, Non-Patent Document 1 describes how "Yotsuboshi," a variety of ever-bearing strawberry, was sown from December to January of the following year, the seedlings were planted in a medium in April, and the strawberry fruits were harvested from July to November. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Hokkaido Horticultural Research Bulletin No. 50 (March 2017) "16. Possibility of cultivating seed-propagated strawberry 'Yotsuboshi' for summer / autumn harvest in Hokkaido" by Fumihiko Kimura and 4 others Summary of the Invention [Problem to be solved by the invention]

[0007] However, when planting seedlings in April as described in Non-Patent Document 1, there is a problem that the strawberry plants are weakened by excessive heat in the summer and the shift to fruiting. In addition, due to recent global warming, even for everbearing varieties, there is an inconvenience that excessive heat suppresses flower bud differentiation in the summer.

[0008] As a result, as shown in FIG. 3 of Non-Patent Document 1, there is a problem that the harvest volume decreases significantly from September to October, especially in October when the market price of strawberries rises sharply.

[0009] It is also possible to use cooling devices such as heat pumps to lower the air temperature in the cultivation facilities in summer, which would prevent the strawberry plants from weakening and promote flower bud differentiation. However, in this case, the running costs of the cooling devices would make it difficult to make a profit.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a method for cultivating everbearing strawberries that allows for a large harvest of strawberry fruits in September and October while reducing the running costs of air conditioning equipment, and a cultivation facility for everbearing strawberries. [Means for solving the problem]

[0011] One aspect of the present invention includes the following aspects.

[0012] [1] A method for cultivating everbearing strawberries, comprising: planting everbearing strawberry seedlings in a culture medium in a cultivation facility consisting of a vinyl greenhouse or a glass greenhouse in May or early June; blocking heat from outside the cultivation facility with a heat-shielding agent applied to the upper surface of the roof of the cultivation facility during at least a portion of the period from July to August; and operating a fine mist cooling device and a circulating fan to suppress an increase in the air temperature within the cultivation facility during at least a portion of the period from July to August.

[0013] [2] A method for cultivating everbearing strawberries as described in [1], comprising supplying cooling water to piping extending through a medium in which everbearing strawberries are cultivated within the cultivation facility during at least a portion of the period from July to August.

[0014] [3] The method for cultivating everbearing strawberries described in [1] or [2], wherein the everbearing strawberries are of the Yotsuboshi variety.

[0015] [4] A cultivation facility for everbearing strawberries composed of a vinyl greenhouse or a glass greenhouse, comprising a roof placed above the everbearing strawberry seedlings, a fine mist cooling device that sprays mist into the cultivation space formed below the roof, and a circulating fan that stirs the air in the cultivation space, and the upper surface of the roof is coated with a heat-insulating agent that blocks heat from outside.

[0016] [5] A cultivation facility for everbearing strawberries as described in [4], comprising piping extending through a culture medium in which everbearing strawberries are planted, a heat pump for cooling water supplied into the piping, and a pressure pump for supplying cooling water cooled by the heat pump into the piping, wherein the cooling water supplied into the piping by the pressure pump is returned to the heat pump.

[0017] [6] A cultivation facility for everbearing strawberries as described in [4] or [5], further comprising a space temperature sensor for detecting the temperature of the cultivation space and a control device for controlling the operation of the mist cooling device, wherein the control device operates the mist cooling device when the temperature of the cultivation space detected by the space temperature sensor is equal to or higher than a predetermined threshold temperature.

[0018] [7] The ever-bearing strawberry cultivation facility described in [5] further comprises a culture medium temperature sensor for detecting the temperature of the culture medium and a control device for controlling the operation of the heat pump, wherein the control device operates the heat pump to supply the cooling water into the piping when the temperature of the culture medium detected by the culture medium temperature sensor is equal to or higher than a predetermined threshold temperature. Effect of the Invention

[0019] According to the present invention, it is possible to provide a method for cultivating everbearing strawberries that allows a large amount of strawberry fruits to be harvested in September and October while reducing the running costs of air conditioning equipment, and a cultivation facility for everbearing strawberries. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic front view of an everbearing strawberry cultivation facility according to a preferred embodiment of the present invention. [Diagram 2] FIG. 2 is a control block diagram of the cultivation facility shown in FIG. 1. [Diagram 3] FIG. 2 is a schematic plan view showing the vicinity of the culture medium cooling device shown in FIG. [Figure 4] 4 is a flowchart showing the cultivation space cooling control by the control device. [Diagram 5] 4 is a flowchart showing medium cooling control by the control device. [Figure 6] This is a graph showing the planting date and start date of harvest for everbearing strawberries. [Figure 7] This is a bar graph showing the monthly yield of Yotsuboshi planted in May and July. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail, with reference to the drawings where necessary.

[0022] FIG. 1 is a schematic front view of an everbearing strawberry cultivation facility 1 according to a preferred embodiment of the present invention, and FIG. 2 is a control block diagram of the cultivation facility 1 shown in FIG.

[0023] The cultivation facility 1 includes a facility main body 4, a cultivation bed 2 arranged inside the facility main body 4, a group of temperature sensors 6 and a solar radiation sensor 7, a group of temperature control devices 5 that adjust the temperature inside the facility main body 4, an irrigation device 12, and a control device 8 that controls part of the group of temperature control devices 5 and the irrigation device 12.

[0024] The facility body 4 is composed of a vinyl greenhouse or a glass greenhouse, and is equipped with a roof 4a located above the strawberry seedlings 3, frame members 4b supporting the roof 4a, skylights 4c, and side windows 4d. Below the roof 4a, a cultivation space 9 for cultivating the strawberry seedlings 3 is formed, and in this cultivation space 9, the cultivation beds 2 are arranged.

[0025] A heat-shielding agent that blocks heat from the outside is applied to the upper surface (outer surface) of the roof 4a. The type of heat-shielding agent is not particularly limited as long as it reflects at least a portion of the infrared or near-infrared radiation irradiated to the cultivation facility 1, but ReduHeat (registered trademark) by Malden Klaw Co., Ltd. is preferably used, for example. The heat-shielding agent is applied to the upper surface of the roof 4a from May to July, and is removed with a remover in the fall when the heat subsides.

[0026] A container 2a is provided on the top of the cultivation bed 2. The container 2a contains a medium in which strawberry seedlings 3 are planted. As a medium for cultivating strawberries, for example, rock wool or coconut shell is preferably used, but is not limited to these. In addition, the material of the container 2a is not particularly limited, but polystyrene foam is used in this embodiment.

[0027] The temperature sensor group 6 detects the temperature inside the facility main body 4. More specifically, the temperature sensor group 6 includes a space temperature sensor 6a that detects the temperature of the cultivation space 9, and a culture medium temperature sensor 6b that detects the temperature of the culture medium contained in the container 2a. The space temperature sensor 6a and the culture medium temperature sensor 6b are each connected to the input side of the control device 8, and output the temperature detection results to the control device 8.

[0028] The solar radiation sensor 7 detects the amount of solar radiation irradiating the vicinity of the culture medium. The solar radiation sensor 7 is connected to the input side of the control device 8, and outputs the detection result of the amount of solar radiation to the control device 8.

[0029] The temperature control device group 5 includes a fine mist cooling device 5a that cools the air in the cultivation space 9 inside the facility main body 4, a circulating fan 5b that eliminates temperature unevenness in the cultivation space 9, a culture medium cooling device 5c that cools the culture medium contained in the container 2a, a skylight opening / closing device 5d, and a side window opening / closing device 5e.

[0030] The fine mist cooling device 5a includes a pipe 5a1 equipped with a plurality of spray nozzles 5a2, a water tank (not shown) for storing water to be sprayed into the cultivation space 9 through the spray nozzles 5a2, and a water supply pump 5a3 for supplying water from the water tank into the pipe 5a1. The pipe 5a1 is attached to the framework member 4b.

[0031] The water supply pump 5a3 is connected to the output side of the control device 8, and is driven or stopped based on a control signal output from the control device 8. While the water supply pump 5a3 is driven, water is supplied from the water storage tank into the pipe 5a1, and the water is sprayed into the cultivation space 9 through the multiple spray nozzles 5a2. As a result, the air in the cultivation space 9 is cooled by the heat of vaporization of the sprayed water.

[0032] The circulation fan 5b includes a blade portion 5b1 that compresses and delivers air, and a blade rotation motor 5b2 that rotates and drives the blade portion 5b1. The blade rotation motor 5b2 is connected to the output side of the control device 8, and is driven by applying a voltage from a driver circuit (not shown) based on a control signal output from the control device 8. The circulation fan 5b rotates the blade portion 5b1 using the blade rotation motor 5b2, and compresses and agitates the air in the cultivation space 9. The circulation fan 5b may be configured to be driven or stopped based on the operation of an operator.

[0033] Culture medium cooling device 5c includes a cooling pressure-transfer device 5c1 and a pipe 5c2 connected to cooling pressure-transfer device 5c1.

[0034] Cooling and pumping device 5c1 includes heat pump unit 5c1a (corresponding to the "heat pump" of the present invention) that cools water, and pumping unit 5c1b that pumps the cooling water cooled by heat pump unit 5c1a into pipe 5c2. In this specification, "cooling water" refers to water that has been cooled to a temperature lower than the temperature of the culture medium.

[0035] The pipe 5c2 is preferably made of a metal such as stainless steel, an alloy, or aluminum, but the material of the pipe 5c2 is not limited, and it may be made of resin, ceramic, or the like.

[0036] The skylight opening / closing device 5d is equipped with a skylight opening / closing motor 5d1 that opens and closes the skylight 4c. The skylight opening / closing motor 5d1 is connected to the output side of the control device 8, and is driven by applying a voltage from a driver circuit (not shown) based on a drive signal output from the control device 8.

[0037] The side window opening / closing device 5e includes a side window opening / closing motor 5e1 that opens and closes the side window 4d. The side window opening / closing motor 5e1 is connected to the output side of the control device 8, and is driven by applying a voltage from a driver circuit (not shown) based on a drive signal output from the control device 8.

[0038] The irrigation device 12 includes an irrigation tube 12a extending over the upper surface of the culture medium, and an irrigation pump 12b for supplying water from a water storage tank to the irrigation tube 12a.

[0039] The irrigation pump 12b is connected to the output side of the control device 8, and is configured to be driven or stopped based on a drive signal output from the control device 8. While the irrigation pump 12b is driven, water is supplied from a water storage tank into the irrigation tube 12a, and the culture medium is irrigated through a large number of holes formed in the irrigation tube 12a.

[0040] In addition, a pipe may be provided between the water storage tank and the irrigation tube 12a, and a liquid fertilizer mixer may be disposed in the pipe so that liquid fertilizer can be supplied to the culture medium through the irrigation tube 12a.

[0041] In this embodiment, the water tank is used for both mist cooling and irrigation, but separate water tanks may be provided for mist cooling and irrigation. In this case, the water tank for irrigation may be configured to contain culture solution instead of water and to supply the culture solution to the medium.

[0042] In addition to the above-mentioned temperature sensor group 6 and solar radiation sensor 7, an input means 11 is connected to the input side of the control device 8 so that an operator can input various data to the control device 8. Using the input means 11, the operator can input and set threshold temperatures used for various controls. The input means 11 is composed of, for example, a touch panel or physical buttons, but is not limited to these.

[0043] The control device 8 is configured with a known microcomputer including a CPU 8a and a memory 8b and its peripheral circuits. The CPU 8a controls the operation of the temperature adjustment device group 5 by reading and executing various programs stored in the memory 8b.

[0044] More specifically, the control device 8 performs cultivation space cooling control, which controls the operation of the mist cooling device 5a to cool the cultivation space 9, culture medium cooling control, which controls the operation of the culture medium cooling device 5c to cool the culture medium 2b, ventilation control, air circulation control, and irrigation control.

[0045] Ventilation control refers to a control in which the skylight 4c and the side windows 4d are opened when the temperature of the cultivation space 9 detected by the space temperature sensor 6a is equal to or higher than a threshold temperature preset using the input means 11, and the skylight 4c and the side windows 4d are closed when the temperature is below the threshold temperature.

[0046] In this case, the threshold temperature may be set, for example, to 22°C as the daytime threshold temperature and 5°C as the nighttime threshold temperature, but the threshold temperatures as the basis for opening and closing the skylight 4c and the side window 4d are not limited to these. The daytime threshold temperature of 22°C is suitable in terms of preventing high-temperature damage to strawberries. The nighttime threshold temperature of 5°C is suitable in terms of promoting the transfer of heat to the fruit after sunset due to the temperature difference with the daytime. In particular, in summer, when the temperature difference between the inside and outside of the facility main body 4 becomes large, the heated air inside the facility main body 4 can be discharged to the outside and the relatively low-temperature outside air can be taken into the facility main body 4.

[0047] The memory 8b stores data on sunrise and sunset times associated with each date of the year. The control device 8 reads out the data on sunset and sunrise times from the current date and the next day's date, and performs ventilation control by determining the period from the sunset time to the sunrise time of the next day as night. Note that it is not necessarily required to configure the device to determine night and day from the sunrise and sunset times in this manner. For example, the data on sunrise and sunset times may be stored in the memory 8b in advance. In this case, it is preferable that the sunrise and sunset times can be changed using the input means 11.

[0048] The air circulation control refers to a control in which, when the temperature of the cultivation space 9 detected by the space temperature sensor 6a is equal to or higher than a threshold temperature preset using the input means 11, the blade rotation motor 5b2 is driven to rotate the blade portion 5b1, thereby circulating the air in the cultivation space 9. The threshold temperature in the air circulation control is set to, for example, 18°C, but is not limited to this.

[0049] The irrigation control refers to a control for increasing or decreasing the number of times of irrigation per day in proportion to the amount of solar radiation in the vicinity of the medium detected by the solar radiation sensor 7. The greater the amount of solar radiation, the greater the number of times of irrigation is controlled to be.

[0050] The culture medium cooling device 5c will be described in detail below.

[0051] FIG. 3 is a schematic plan view showing the vicinity of the culture medium cooling device 5c shown in FIG.

[0052] The pipe 5c2 is shaped such that a portion of the pipe in the extending direction is branched into three branch pipes 5c2a to 5c2c, and both ends 5c2d and 2c2e are connected to the cooling and pressure-feeding device 5c1. Hereinafter, the end 5c2d on one side of the pipe 5c2 is referred to as "one end 5c2d," and the end 5c2e on the other side is referred to as "the other end 5c2e." The shape of the pipe connected to the cooling and pressure-feeding device 5c1 is not particularly limited, and it is sufficient that a portion of the pipe is disposed in the culture medium 2b.

[0053] The three branch pipes 5c2a to 5c2c each extend through the front surface 2a1 and rear surface 2a2 of the separate containers 2a and through the culture medium 2b in the depth direction of FIG. 1, and merge into one pipe after penetrating the rear surface 2a2.

[0054] The heat pump unit 5c1a of the cooling pump-transfer device 5c1 receives the water in the pipe 5c2 from the end 5c2e of the pipe 5c2 and cools the water. In this cooling, the heat pump unit 5c1a performs heat exchange to transfer heat from the water taken in from the pipe 5c2 to the air outside the facility main body 4.

[0055] The cooling pressure-feed device 5c1 is connected to the output side of the control device 8. The pressure-feed pump unit 5c1b pressure-feeds and supplies cooling water from one end 5c2d into the pipe 5c2 based on a control signal from the control device 8. The heat pump unit 5c1a is always active except when the water temperature is equal to or lower than a preset target temperature, but the pressure-feed pump unit 5c1b is turned off in the standard state and supplies cooling water into the pipe 5c2 only when a control signal from the control device 8 is received.

[0056] The cooling water supplied from one end 5c2d into the pipe 5c2 is transferred in the direction of the arrow shown in Fig. 3 and passes through the culture medium 2b. At this time, the culture medium 2b is cooled by the pipe 5c2, which is cooled by contact with the cooling water.

[0057] The water that has passed through the culture medium 2b in this manner is returned from the other end 5c2e of the pipe 5c2 to the heat pump section 5c1a, and after being cooled in the heat pump section 5c1a, is supplied again into the pipe 5c2 from one end 5c2d based on a control signal from the control device 8.

[0058] In this way, by circulating the cooling water between the pipe 5c2, the heat pump unit 5c1a, and the pressure pump unit 5c1b, the running cost for cooling the culture medium 2b can be reduced. If the force of the water weakens in the pipe 5c2 and the water cannot be returned to the cooling pressure pump 5c1, a pressure pump for increasing the flow rate may be provided separately in the pipe 5c2.

[0059] In addition, it is not necessarily required to circulate the water passed through the pipe 5c2 into the cooling and pumping device 5c1. When the water supplied from the cooling and pumping device 5c1 into the pipe 5c2 is not circulated to the cooling and pumping device 5c1, only the one end 5c2d that receives the cooling water from the cooling and pumping device 5c1 may be connected to the heat pump.

[0060] The culture medium cooling device 5c can lower the temperature of the culture medium 2b, thereby maintaining the strength of the strawberry plants, especially in the summer, preventing a decrease in the harvest yield in September and October, and promoting the growth of strawberry roots.

[0061] The cultivation space cooling control will be described in detail below. FIG. 4 is a flowchart showing the cultivation space cooling control by the control device 8.

[0062] First, the control device 8 acquires data on the detected temperature of the air in the cultivation space 9 from the space temperature sensor 6a (step S1).

[0063] Next, the control device 8 judges whether or not the detected temperature acquired from the space temperature sensor 6a is equal to or higher than a threshold temperature preset using the input means 11 (step S2). The threshold temperature used for the cultivation space cooling control is, for example, 22°C, but is not limited thereto.

[0064] If the result of the determination is that the detected temperature is lower than the threshold temperature, the control device 8 repeats obtaining the detected temperature from the space temperature sensor 6a and making a determination until the detected temperature becomes equal to or higher than the threshold temperature.

[0065] On the other hand, if the result of the determination is that the detected temperature is equal to or higher than the threshold temperature, the control device 8 outputs a control signal for the water supply pump 5a3 to operate the mist cooling device 5a (step S3).

[0066] As a result, water is sprayed into the cultivation space 9 through the spray nozzle 5a2, and the air in the cultivation space 9 is cooled. The operation time of the water supply pump 5a3 is set to 2 minutes, but is not limited to this.

[0067] Thereafter, the control device 8 operates the fine mist cooling device 5a after a predetermined operating time has elapsed. A software timer or hardware timer (not shown) is used to measure the predetermined operating time.

[0068] When the water spraying ends in this way, the control device 8 ends the cultivation space cooling control. After that, the control device 8 counts a predetermined pause time from the end of the water spraying. Then, when the pause time has elapsed, the control device 8 starts the cultivation space cooling control again, and acquires the detected temperature of the air in the cultivation space 9 in step S1. After that, the cultivation space cooling control and the counting of the predetermined pause time are repeatedly performed.

[0069] Here, the predetermined downtime is a time during which the water supply pump 5a3 is not operated to wait for the temperature of the cultivation space 9 to drop after spraying water. In this embodiment, the downtime is set to 20 minutes, but is not limited to this. Although it is not always necessary to provide a downtime, providing a downtime can reduce water consumption.

[0070] According to the above-described cultivation space cooling control, the temperature of the cultivation space 9 can be kept within a range of about ±2°C of the air temperature outside the facility main body 4. Therefore, the strength of the strawberry plants can be maintained, particularly in the summer, and a decrease in the harvest volume in September and October can be suppressed.

[0071] In addition, in the cultivation space cooling control, the mist cooling device 5a is used to suppress the temperature of the cultivation space 9, so that the running cost can be suppressed compared to the case where the temperature of the cultivation space 9 is suppressed using a heat pump, etc. For example, the outside air temperature in Hokkaido in summer fluctuates in the range of about 15°C to 33°C.

[0072] FIG. 5 is a flowchart showing the culture medium cooling control by the control device 8.

[0073] First, the control device 8 acquires data on the detected temperature of the culture medium 2b from the culture medium temperature sensor 6b (step SS1).

[0074] Next, the control device 8 determines whether or not the detected temperature acquired from the culture medium temperature sensor 6b is equal to or higher than a threshold temperature preset using the input means 11 (step SS2). The threshold temperature used for the culture medium cooling control is, for example, 18°C, but is not limited to this.

[0075] If the result of the determination is that the detected temperature is lower than the threshold temperature, the control device 8 repeats obtaining the detected temperature from the space temperature sensor 6a and making a determination until the detected temperature becomes equal to or higher than the threshold temperature.

[0076] On the other hand, if the detected temperature is equal to or higher than the threshold temperature, the control device 8 outputs a control signal to the cooling and pumping device 5c1 to operate the pump unit 5c1b and start circulating the cooling water between the pipe 5c2 and the cooling and pumping device 5c1 (step SS3). As a result, the cooling water passes through the medium 2b, and the medium 2b is cooled.

[0077] After the circulation of the cooling water is started, the control device 8 acquires data on the detected temperature of the culture medium 2b from the culture medium temperature sensor 6b (step SS4).

[0078] Next, the control device 8 determines whether or not the acquired detected temperature is lower than the above-mentioned threshold temperature (step SS5).

[0079] If the result of the determination is that the detected temperature is equal to or higher than the threshold temperature, the control device 8 repeats obtaining and determining the detected temperature until the detected temperature becomes lower than the threshold temperature.

[0080] On the other hand, if the result of the determination is that the detected temperature is lower than the threshold temperature, the control device 8 outputs a control signal to the cooling pressure-feed device 5c1 to stop the pressure-feed pump unit 5c1b, thereby stopping the circulation of the cooling water (step SS6).

[0081] After the cooling water circulation is stopped, the control device 8 ends the culture medium cooling control. After that, the control device 8 counts a predetermined downtime from the stop of the cooling water circulation. Then, when the downtime has elapsed, the control device 8 starts the culture medium cooling control again and acquires the detected temperature of the culture medium 2b in step SS1. After that, the culture medium cooling control and the counting of the predetermined downtime are repeatedly performed.

[0082] Here, the downtime is the time during which the pressure-feed pump unit 5c1b is not operated to wait for the temperature of the culture medium 2b to drop after the circulation of the cooling water is stopped. In this embodiment, the downtime is set to 10 minutes, but is not limited to this. It is not always necessary to provide a downtime, but providing a downtime can reduce the power consumption of the pressure-feed pump unit 5c1b.

[0083] According to this embodiment, the culture medium 2b and the cultivation space 9 can be cooled even in the summer, so that weakening of the strawberry plants in the summer can be suppressed, and a large amount of strawberry fruits can be harvested even in September, October, November, and December.

[0084] Furthermore, in the cultivation facility 1, the temperature control device group 5 includes a fine mist cooling device 5a, a circulation fan 5b, a culture medium cooling device 5c, a skylight opening / closing device 5d, and a side window opening / closing device 5e, and a heat insulating agent is applied to the outer surface of the roof 4a. Therefore, the running costs can be significantly reduced compared to operating a cooling device using a heat pump.

[0085] [Other embodiments] In one embodiment, the present invention provides a method for cultivating everbearing strawberries, which comprises planting everbearing strawberry seedlings in a medium in a cultivation facility made of a vinyl greenhouse or a glass greenhouse in May or early June, blocking heat from outside the cultivation facility with a heat-shielding agent applied to the upper surface of the roof of the cultivation facility for at least a part of the period from July to August, and suppressing an increase in air temperature in the cultivation facility by operating a fine mist cooling device and a circulating fan for at least a part of the period from July to August. Note that early June refers to the period from June 1 to June 10. In this embodiment, cooling water may be supplied to the piping extending through the medium in which the everbearing strawberry is cultivated during at least a part of the period from July to August. This embodiment will be described in detail below. The description will be given on the assumption that the strawberry is cultivated in Japan.

[0086] The variety of everbearing strawberry cultivated by this cultivation method is not particularly limited, and examples include "Yotsuboshi," "Natsuakari," "Tochihitomi," "Suzuakane," etc. Among these, "Yotsuboshi" is preferably used because it has superior qualities such as sweetness and mouthfeel compared to other everbearing strawberries.

[0087] In particular, in the summer, by planting and cultivating evergreen strawberries such as "Yotsuboshi" in May or late June while keeping the temperature in the cultivation space down with a fine mist cooling device, a good harvest can be expected from around August to around June of the following year.

[0088] As the cultivation facility, the above-mentioned cultivation facility 1 can be suitably used, but it is sufficient that it is composed of a vinyl greenhouse or a glass greenhouse, and other configurations are not particularly limited.

[0089] For example, the type of culture medium in the cultivation facility is not particularly limited. In addition to the culture medium 2b of the cultivation facility 1 described above, soil culture may be performed using soil as a culture medium.

[0090] The piping that passes through the medium can be, for example, the above-mentioned piping 5c2, but the material and shape of the piping are not particularly limited as long as a part of the piping extends through the medium and can transport the cooling water generated by the heat pump. Note that the piping only needs to be partially disposed in the medium, and it is not necessary to dispose the entire piping in the medium. The piping is preferably disposed in the medium before planting the seedlings, but may be disposed after planting.

[0091] As the cooling water, well water or water cooled by a heat pump can be suitably used.

[0092] As the heat pump, for example, the heat pump section 5c1a of the cooling and pumping device 5c1 of the above-mentioned cultivation facility 1 can be suitably used, but the type is not particularly limited as long as it can supply cooling water to the piping extending through the culture medium. However, it is preferable that the heat pump is capable of receiving water in the piping extending through the culture medium and cooling the water. A suitable example of the cooling and pumping device 5c1 is the heat pump module chiller "Voxcel (registered trademark)" by Mitsubishi Heavy Industries.

[0093] The time to plant everbearing strawberry seedlings is May or early June. The areas for planting and subsequent cultivation are preferably Hokkaido, the Tohoku region, or highland areas with an altitude of 700m or higher to avoid the excessive heat of summer, but are not limited to these areas.

[0094] In Japan, in general, seedlings of everbearing strawberries are raised from July to September, and after refrigeration and short-day treatment in some cases, they are planted from September to October. In this case, fruit harvesting begins from November to January of the following year, and harvesting takes place from April to June. In general, everbearing strawberries are planted from March to May, and harvesting takes place from June to July onwards. In this case, it is difficult to harvest a large amount from September to October without suppressing the rise in temperature inside the cultivation facility.

[0095] In contrast, in the cultivation method of this embodiment, everbearing strawberry seedlings are planted in May or early June, and as described in detail later in the Examples, after planting, especially during the summer, the temperature rise in the cultivation space 9 in which the seedlings are cultivated is suppressed, and cultivation is performed in a state in which the translocation to fruit is not yet active, so that a large number of strawberry fruits can be harvested from September to October. In addition, the strawberries can be harvested over a long period from August to around June of the following year. Note that if everbearing strawberries are planted in May or early June and cultivated without temperature control in the summer, problems such as delayed harvest time, reduced yield, and reduced fruit quality are likely to occur.

[0096] It is desirable to apply a heat-shielding agent that blocks heat from the outside to the top surface of the cultivation facility (specifically, the outer surface of the roof) in order to suppress temperature rise in the summer. By applying a heat-shielding agent to the roof of the cultivation facility, it is possible to suppress temperature rise in the cultivation space as well as temperature rise in the culture medium. As a heat-shielding agent, for example, ReduHeat (registered trademark) by Malden Klaw Co., Ltd. can be suitably used, but the type of the heat-shielding agent is not particularly limited as long as it reflects at least a part of the infrared or near-infrared radiation irradiated to the cultivation facility.

[0097] It is preferable to use a heat shield to block heat from outside the cultivation facility for at least a part of the period between July and August. The timing of applying the heat shield will depend on the weather of the year, but it is preferable to apply it by July at the latest. Note that the heat shield will gradually peel off due to rain, so if it is applied before the rainy season, it may be reapplied after the rainy season ends.

[0098] In addition, it is advisable to remove the heat-shielding agent with a remover around October when the summer ends and the temperature drops, which will allow the temperature inside the facility to increase after October and promote photosynthesis in the strawberry seedlings.

[0099] In the cultivation after planting, it is preferable to supply a culture solution to the medium or to irrigate the medium while appropriately applying additional fertilizer. The additional fertilizer may be a liquid fertilizer or a slow-release fertilizer.

[0100] During at least a part of the period from July to August (preferably from June to September), it is preferable to supply cooling water cooled by a heat pump to the piping extending through the medium in which the everbearing strawberries are grown.

[0101] In this way, by supplying cooling water to the pipes extending through the culture medium during the hot summer months, it is possible to reduce the running costs of air conditioning while maintaining the strength of the strawberry seedlings, and to prevent a decrease in fruit yield from September to October, especially in October.

[0102] It is preferable that the water supplied from the heat pump to the piping extending through the culture medium is returned to the heat pump to be cooled and then supplied again to the piping. By circulating the water between the piping and the heat pump in this way, the running costs can be further reduced.

[0103] Furthermore, it is preferable to operate a mist cooling device in the cultivation facility during at least a part of the period from July to August (preferably from June to September) to suppress the rise in air temperature in the cultivation facility. By operating the mist cooling device, it is possible to significantly reduce running costs compared to operating a heat pump to cool the cultivation space. In addition, by operating a circulation fan in conjunction with the operation of the mist cooling device to eliminate temperature unevenness in the cultivation facility, the effect of suppressing temperature rise by the mist cooling device can be further enhanced. Note that operating the fine mist cooling device and the circulating fan at least part of the time period from July to August does not only mean operating continuously for more than 24 hours, but also includes operating for a part of a day. For example, as in the above-mentioned cultivation facility 1, during July and August, they can be operated as appropriate when the temperature of the cultivation space is equal to or higher than an appropriately set threshold temperature, or when there is a risk of high-temperature damage to strawberry seedlings. The same applies to the supply of cooling water into the piping in the culture medium, as described above.

[0104] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these modifications are also included in the scope of the present invention.

[0105] For example, in the embodiment of the cultivation facility 1 shown in Figures 1 to 5, elevated cultivation is performed using the cultivation beds 2, but soil cultivation may also be performed. In the case of soil cultivation, the piping of the medium cooling device extends through the medium (soil) accumulated on the ground.

[0106] The above has described in detail the embodiments of the cultivation facility 1 for everbearing strawberries and the cultivation method for everbearing strawberries. Below, an example of the cultivation method for everbearing strawberries will be described. EXAMPLES

[0107] In this example, a detailed example will be described in which "Yotsuboshi", a variety of ever-bearing strawberry that is of high quality from a consumer perspective, was planted in May and cultivated under natural sunlight hours.

[0108] (Cultivation environment) The cultivation facility was a vinyl greenhouse with a frontage of 8 m. Styrofoam containers were placed on the cultivation beds, and waterproof sheets and root-proof sheets were laid on the containers. The containers were then filled with rock wool medium for elevated cultivation. A total of seven cultivation beds were prepared.

[0109] (planting) FIG. 6 is a graph showing the planting date and start date of harvest for everbearing strawberries.

[0110] In early April, Yotsuboshi seeds were sown in a cell tray with 406 small spaces for accommodating the medium, and on May 19th, they were planted in the rock wool medium mentioned above. At this time, the strawberry seedlings had three leaves. When planting, the plants were spaced 20cm apart and planted in two staggered rows. The planting density was 6957 plants / 10a, and the amount of medium per plant was 2.45L.

[0111] In addition, Yotsuboshi is often cultivated for harvest in the winter, just like evergreen strawberries, because the fruits have low heat tolerance and flower bud differentiation is unstable in hot environments. For this reason, we also prepared a control plot where Yotsuboshi was planted on July 5th, slightly earlier than the planting time for typical evergreen strawberries.

[0112] For reference, Fig. 6 also shows the start of harvesting when the strawberries are planted in March and cultivated under the same conditions as in the present embodiment. In general, when everbearing strawberries are planted in March, the amount of fruit produced decreases from September onwards because the fruit is actively converted into fruits in the summer.

[0113] (Temperature control of cultivation space) During cultivation in the summer, the fine mist cooling device was automatically operated when the temperature of the cultivation space detected by the space temperature sensor was 22°C or higher. In addition, when the temperature of the cultivation space detected by the space temperature sensor was 22°C or higher during the day and 5°C or higher at night, the skylight and side windows were automatically opened, and when it was below 22°C or below 5°C at night, the skylight and side windows were automatically closed. In addition, during the summer, the circulation fan was automatically operated at 18°C ​​or higher.

[0114] Thanks to the fine mist cooling system, skylights, side windows and circulating fans, the temperature outside the facility during summer remained within a range of approximately ±2°C.

[0115] ReduHeat (registered trademark) by Maldenclaw was applied to the top surface (outer surface) of the roof of the cultivation facility on July 11th as a heat shield (heat shield coating).

[0116] The heat-shielding agent was then removed using a remover on September 29. In addition, the skylights and side windows were kept closed from November onwards, when temperatures began to drop.

[0117] (Temperature control of culture medium) During cultivation in the summer, when the medium temperature detected by the medium temperature sensor was 18°C ​​or higher, water cooled by the heat pump was automatically pumped into the piping extending through the medium, and the water was circulated between the piping and the heat pump. The heat pump used was Mitsubishi Heavy Industries' heat pump module chiller "Voxcel (registered trademark)".

[0118] With the medium cooling device equipped with this heat pump and piping, the temperature of the medium in summer was within the range of approximately 18℃ to 23℃.

[0119] In addition, after November when the temperature started to drop, the culture medium was heated by supplying hot water into the piping using a heat pump.

[0120] (Irrigation) During cultivation, watering was carried out by supplying the medium with OAT Agrio's OAT House A formulation culture solution, and the EC was controlled within the range of 0.4 to 0.6 mS / cm according to growth.

[0121] (Cultivation results) Table 1 below shows the monthly yields of Yotsuboshi planted in May and July, and Figure 7 is a bar graph showing the monthly yields of Yotsuboshi planted in May and July.

[0122] [Table 1]

[0123] In the case of Yotsuboshi trees planted in July in the control area, fruit harvesting began on November 5th, and the yield per plant was over 50g in December. However, no fruit could be harvested in September and October.

[0124] In contrast, in the case of Yotsuboshi plants planted in May, buds on the first inflorescence could be confirmed in more than 50% of the plants by early August, and in mid-August, buds on the first inflorescence could be confirmed in more than 90% of the plants.

[0125] Then, strawberry harvesting began on August 18. The number of days from planting in May to the start of harvesting was 91 days.

[0126] The average yield per plant up to December was 246.6g, and there was no significant drop in yield from the start of harvest to the end of December, especially in September and October, with a stable yield of over 50g per plant on average. The fact that a large harvest could be achieved from September to December, when the market price of strawberries soars, especially in October when prices reach their highest, is extremely beneficial for strawberry producers.

[0127] The reason why Yotsuboshi plants planted in May were able to produce a stable yield until December is thought to be that the stress on the strawberry plants was greatly reduced, especially in the summer, due to the operation of the temperature control devices and the use of heat insulation agents, and because the plants were not at a stage of growth where many fruits could be harvested in July and August, the strength of the Yotsuboshi plants was able to be maintained until September and beyond.The strawberry fruits obtained had an average sugar content of 12.6%, an acidity of 0.52%, and a sugar-acid ratio of 24.0, and were of very good quality due to their high sugar content and sugar-acid ratio.

[0128] From the above results, it was confirmed that by planting everbearing strawberries in May and suppressing the temperature rise inside the cultivation facility by operating the temperature control devices and using heat insulation agents, especially in the summer, a large yield can be secured in September and October. [Explanation of symbols]

[0129] 1: Cultivation facility 2: Cultivation bed 2a: Container 2b: Culture medium 3: Seedling 4: Facility body 4a: Roof 4b: Frame member 4c: Skylight 4d: Side window 5: Temperature control device group 5a: Fine mist cooling device 5a1: Piping 5a2: Spray nozzle 5a3: Water supply pump 5b: Circulation fan 5b1: Blade section 5b2: Blade rotation motor 5c: Culture medium cooling device 5c1: Cooling pressure transfer device 5c2: Piping 5c2a-5c2c: Branching piping 5d: Skylight opening / closing device 5e: Side window opening / closing device 5d1: Skylight opening / closing motor 5e1: Side window opening / closing motor 5e: Side window opening / closing device 6: Temperature sensor group 6a: Space temperature sensor 6b: Culture medium temperature sensor 7: Solar radiation sensor 8: Control device 9: Cultivation space 11: Input means 12: Irrigation device 12a: Irrigation tube 12b: Irrigation pump

Claims

1. Everbearing strawberry seedlings are planted in a cultivation facility consisting of a vinyl house or a glass house in May or early June, During at least a part of the period from July to August, a heat insulating agent is applied to an upper surface of the roof of the cultivation facility to block heat from outside the cultivation facility; and A method for cultivating everbearing strawberries, comprising operating a fine mist cooling device and a circulating fan during at least a part of the period from July to August to suppress an increase in air temperature within the cultivation facility.

2. The method for cultivating everbearing strawberries according to claim 1, further comprising supplying cooling water to a piping extending through a medium for cultivating everbearing strawberries in the cultivation facility during at least a portion of the period from July to August.

3. The method for cultivating everbearing strawberries according to claim 1 or 2, wherein the everbearing strawberries are of the Yotsuboshi variety.

4. A cultivation facility for everbearing strawberries composed of a vinyl house or a glass house, A roof placed above the evergreen strawberry plants; A fine mist cooling device that sprays mist into the cultivation space formed under the roof; A circulation fan that stirs the air in the cultivation space, The cultivation facility for everbearing strawberries has a heat insulating agent applied to the upper surface of the roof to block heat from the outside.

5. A pipe extending through the medium in which the evergreen strawberries are planted, A heat pump that cools water supplied into the pipe; a pressure pump that supplies the cooling water cooled by the heat pump into the piping, The ever-bearing strawberry cultivation facility according to claim 4, wherein the cooling water supplied into the piping by the pressure pump is returned to the heat pump.

6. A space temperature sensor for detecting the temperature of the cultivation space; A control device for controlling the operation of the mist cooling device is further provided. The evergreen strawberry cultivation facility described in claim 4 or 5, wherein the control device operates the fine mist cooling device when the temperature of the cultivation space detected by the space temperature sensor is equal to or higher than a predetermined threshold temperature.

7. A culture medium temperature sensor for detecting the temperature of the culture medium; A control device for controlling the operation of the pressure pump is further provided. The ever-bearing strawberry cultivation facility described in claim 5, wherein the control device operates the pressure pump to supply the cooling water into the piping when the temperature of the culture medium detected by the culture medium temperature sensor is equal to or higher than a predetermined threshold temperature.

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