How to grow asparagus

Abstract

To provide a method for cultivating asparagus whereby: in long-term greenhouse cultivation of asparagus, it is possible to increase the yield during the off-crop season without a decrease in the yield the next spring.SOLUTION: A method for cultivating asparagus includes, in long-term greenhouse cultivation of asparagus, applying carbon dioxide of 600-2000 ppm at least for a certain period between the fall and the early winter.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for cultivating asparagus. [Background technology]

[0002] Asparagus is a vegetable that is available in stores throughout the year, but autumn and winter are the off-season for domestically produced asparagus. As a result, the amount of imported asparagus circulating in the market from October to February is greater than the amount of domestically produced asparagus. Asparagus loses its freshness easily, and although technology for preserving freshness when imported has improved, there is still high demand for domestically produced asparagus during the off-season.

[0003] One method of asparagus production is greenhouse long-term harvest cultivation, in which the crop is harvested continuously from spring to autumn in a greenhouse. Long-term greenhouse cultivation is a cultivation method that allows for higher yields and more stable production than open-field cultivation. However, because the unit price of domestically produced asparagus in the spring (spring buds) is high, a production method that does not affect the yield of spring buds is required for practical off-season production.

[0004] One production technique reported for extending the harvest period during the autumn-winter off-season in greenhouse long-term harvest cultivation is the foliage spraying of a plant growth regulator whose main ingredient is benzylaminopurine, which has an action similar to cytokinin. It has been reported that foliage spraying of a plant growth regulator whose main ingredient is benzylaminopurine in October to November promotes sprouting of young shoots for about a month thereafter, resulting in an increase in the yield of young shoots during the off-season compared to untreated shoots (Non-Patent Documents 1 and 2).

[0005] Another off-season production technique for asparagus is forced cultivation, in which plants are cultivated in open fields, then dug up in autumn and winter, laid flat in a greenhouse, and harvested under warm conditions. This cultivation method ensures sufficient exposure to low temperatures to break dormancy, and in some areas of Hokkaido, shipments begin in November (Non-Patent Document 3). In Iwate Prefecture, a technique has been developed in which plants dug up in mid-October are laid flat, and then subjected to high-temperature treatment at around 28°C for several days 10 to 2 weeks after laying down, thereby breaking dormancy and enabling off-season production from November onwards (Non-Patent Document 4). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Ikeuchi, T. and Kobayakawa, H. 2000. Development of year-round asparagus production technology (Part 1) Harvesting in the off-season using BA. Bulletin of the Kagawa Agricultural Experiment Station, 52, 23-31. [Non-patent document 2] Uesugi, T., Ozawa, T., Matsuki, H., and Oguchi, B. 1996. Benzyladenine promotes germination in retarding asparagus cultivation. Report of the Nagano Prefectural Vegetable and Flower Experiment Station. 9.1-9. [Non-patent document 3] Hokuren. 2015. Bihoro Town's efforts in forced cultivation. Agriport. 116.7-8. [Non-patent document 4] Iwate Prefectural Agricultural Research Center. November production technique using high temperature treatment for forced asparagus cultivation. FY2015 Tohoku Agricultural Research Results Information Summary of the Invention [Problem to be solved by the invention]

[0007] When plant growth regulators containing benzylaminopurine as the main ingredient are sprayed on stems and leaves, the effect of promoting sprouting of young shoots after benzylaminopurine treatment may not be stable depending on the concentration of the spray solution, the condition of the plant, weather conditions, etc. Furthermore, if the yield during the off-season increases due to benzylaminopurine treatment, it is thought that the young shoots that will sprout the following spring will be harvested early, consuming photosynthetic products accumulated in storage roots, etc., which tends to result in a lower yield of spring shoots the following year. In forced cultivation, digging up the plants grown in the open field and then planting them in the greenhouse requires a great deal of labor. In addition, in forced cultivation, the number of plants grown is directly linked to the yield of young stems, but with the recent trend toward more extreme weather, damage from diseases such as stem blight during plant cultivation in the open field is becoming more serious, and the factors that make production unstable are increasing.

[0008] Therefore, an object of the present invention is to provide a method for cultivating asparagus in a greenhouse for long-term harvest, which enables increased yields during the off-season without reducing the yield in the spring of the following year. [Means for solving the problem]

[0009] The present disclosure includes the following aspects. [1] A method for cultivating asparagus in a greenhouse for long-term harvest, comprising applying 600 to 2000 ppm of carbon dioxide during at least part of the period from autumn to early winter. [2] The method for cultivating asparagus according to [1], wherein the carbon dioxide is applied for 10 days or more. [3] The method for cultivating asparagus according to [1] or [2], wherein the application of carbon dioxide is carried out for 6 hours or more during the day. [Effects of the Invention]

[0010] According to the present invention, there is provided a method for cultivating asparagus in a greenhouse for extended harvesting, which enables increased yield during the off-season without reducing the yield in the spring of the following year. [Brief explanation of the drawings]

[0011] [Figure 1] 1 shows the change in CO2 concentration in a sunlight-type artificial climate chamber during the CO2 application period in an asparagus cultivation test in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0012] In one aspect, the present invention provides a method for cultivating asparagus in a greenhouse for long-term harvest, comprising applying carbon dioxide at 600 to 2000 ppm during at least a part of the period from autumn to early winter.

[0013] The asparagus cultivation method according to this embodiment is applicable to greenhouse cultivation. "House cultivation" refers to a method of cultivating crops in a facility such as a vinyl greenhouse or glass greenhouse. The greenhouse facility for greenhouse cultivation is preferably equipped with temperature control equipment, ventilation equipment, water supply and drainage equipment, carbon dioxide supply equipment, etc. "Long-term greenhouse harvesting" is a cultivation method in which asparagus is grown in a greenhouse for a long period of time. In long-term asparagus harvesting, after the spring buds are harvested in the spring, some stems are left unharvested and allowed to grow (erectile stems), and the young stems that sprout thereafter continue to be harvested until autumn. In long-term greenhouse harvesting, although this varies by region, spring buds are usually harvested for about one to two months between January and April, and summer and autumn buds are harvested between May and October. In conventional long-term greenhouse cultivation, budding stops after this period, marking the off-season.

[0014] The asparagus cultivation method according to this embodiment is characterized in that high concentrations of carbon dioxide are applied during at least part of the autumn to winter period during greenhouse long-term harvest cultivation. By applying carbon dioxide from autumn to winter, the emergence of spears is promoted, improving the yield. This makes it possible to increase the spear yield during the autumn to winter period, which is the off-season in conventional long-term harvest cultivation. Carbon dioxide can be applied using a carbon dioxide application device such as a kerosene combustion system, LPG combustion system, or liquefied carbon dioxide system, or by applying organic matter such as bulky organic matter or compost into a greenhouse and generating carbon dioxide through the decomposition activity of microorganisms.

[0015] The application period of carbon dioxide may be at least a part of the period from autumn to early winter. In Japan, "autumn" usually refers to the period from September to mid-November (for example, from about September 1 to November 15). "Early winter" usually refers to the period from mid-November to early December (for example, from about November 15 to December 10). "Autumn to early winter" includes, for example, the period from September 1 to about December 10.

[0016] Examples of times to start applying carbon dioxide include autumn (preferably from mid- to late autumn); when the average daily temperature begins to drop below 20°C; and when autumn bud harvesting ends in conventional long-term greenhouse cultivation. The application of carbon dioxide may be started when the temperature inside the greenhouse does not rise too much even when the greenhouse is sealed, for example, when the average daily temperature begins to drop to 20°C or below, 19°C or below, 18°C ​​or below, 17°C or below, or 16°C or below. For example, in the Kyushu region, the start time of carbon dioxide application may be October or November. The start time of carbon dioxide application can be, for example, from October 1st to before November 20th. Examples of the start time of carbon dioxide application include after October 10th, after October 15th, after October 20th, and after October 25th. Examples of the start time of carbon dioxide application include before November 20th, before November 15th, before November 10th, before November 5th, and before October 31st. Specific examples of the start time of carbon dioxide application, depending on the weather conditions of the year, include, for example, from October 1st to before November 20th, from October 10th to before November 10th, from October 15th to before November 5th, and from October 20th to before October 31st.

[0017] The timing for ending the application of carbon dioxide is not particularly limited, and application may be ended at any time after the start of application. In winter, asparagus cannot be expected to produce spears even if carbon dioxide is applied due to the drop in temperature. Therefore, the application of carbon dioxide may be ended when spears no longer appear. The timing for ending the application of carbon dioxide may be determined in accordance with changes in the yield of spears, taking into account cost-effectiveness. For example, the application of carbon dioxide may be ended when the asparagus turns yellow. Carbon dioxide application may be terminated, for example, when the average daily temperature begins to drop below 8°C, below 9°C, below 10°C, or below 11°C. For example, in the Kyushu region, the end time of carbon dioxide application may be November or December. The end time of carbon dioxide application can be, for example, from November 1st to before December 20th. Examples of the end time of carbon dioxide application include after November 10th, after November 15th, after November 20th, and after November 25th. Examples of the end time of carbon dioxide application include before December 15th, before December 10th, before December 5th, before November 30th, and before November 25th. Specific examples of the end time of carbon dioxide application, depending on the weather conditions of the year, include, for example, from November 1st to before December 20th, from November 10th to before December 10th, from November 15th to before December 5th, and from November 20th to before November 31st.

[0018] Carbon dioxide may be applied, for example, from autumn to early winter, during a period when the average daily temperature is 8°C or higher and 20°C or lower. Examples of lower limits for the average daily temperature during the carbon dioxide application period include 8°C or higher, 9°C or higher, 10°C or higher, and 11°C or higher. Examples of upper limits for the average daily temperature during the carbon dioxide application period include 20°C or lower, 19°C or lower, 18°C ​​or lower, 17°C or lower, and 16°C or lower. Examples of ranges for the average daily temperature during the carbon dioxide application period include 8°C or higher and 20°C or lower, 9°C or higher and 20°C or lower, 10°C or higher and 20°C or lower, and 11°C or higher and 20°C or lower.

[0019] The application period of carbon dioxide is not particularly limited, but is preferably 10 days or more. Examples of the application period of carbon dioxide include 10 days or more, 15 days or more, 20 days or more, and 25 days or more. The upper limit of the application period of carbon dioxide is not particularly limited, but can be, for example, 60 days or less, 50 days or less, 40 days or less, or 30 days or less. Specific examples of application periods include, but are not limited to, 10 to 60 days, 15 to 50 days, and 20 to 40 days. Carbon dioxide may be applied continuously or intermittently during the application period, but it is preferably applied daily during the application period.

[0020] The concentration of carbon dioxide to be applied is not particularly limited as long as it is in the range of 600 to 2000 ppm. Examples of lower limits of carbon dioxide concentration include 650 ppm or more, 700 ppm or more, 750 ppm or more, 800 ppm or more, 850 ppm or more, 900 ppm or more, 950 ppm or more, and 1000 ppm or more. Examples of upper limits of carbon dioxide concentration include 1800 ppm or less, 1600 ppm or less, 1500 ppm or less, 1400 ppm or less, and 1200 ppm or less. Examples of carbon dioxide concentration ranges include, but are not limited to, 650 to 1800 ppm, 700 to 1600 ppm, 800 to 1500 ppm, 900 to 1500 ppm, and 1000 to 1500 ppm.

[0021] Carbon dioxide application may be carried out throughout the day or only during the day. "Daytime" refers to the time from sunrise to sunset. Since photosynthesis does not occur at night, carbon dioxide application is ineffective. Therefore, it is preferable to apply carbon dioxide during the day. Carbon dioxide application can be carried out, for example, for 6 hours or more, 7 hours or more, 8 hours or more, 9 hours or more, or 10 hours or more during the day. Examples of the daily application time of carbon dioxide include 6 to 12 hours, 7 to 12 hours, 8 to 12 hours, 9 to 12 hours, and 10 to 12 hours during the day.

[0022] During the application period of carbon dioxide, the temperature inside the greenhouse may or may not be controlled. When controlling the temperature inside the greenhouse, the daytime temperature may be set to about 15 to 30°C and the nighttime temperature may be set to about 10 to 17°C.

[0023] In the asparagus cultivation method according to this embodiment, asparagus can be cultivated in the same manner as in ordinary greenhouse long-term harvest cultivation, except that carbon dioxide is applied from autumn to early winter. In greenhouse long-term harvest cultivation of asparagus, seeds are sown in nursery pots and then grown in a field within the greenhouse. If planting is done in the spring, young stalks can be harvested from autumn in the first year after planting. Carbon dioxide application can also be done from autumn to early winter in the first year after planting. After harvesting during the carbon dioxide application period, asparagus stalks are harvested once they have completely yellowed. Spring buds can be harvested from the second year after planting. After harvesting the spring buds in spring, some stems are left unharvested to grow (erectile stems), and the young stems that sprout afterwards are harvested until autumn. Carbon dioxide application can be carried out from autumn to winter on plants from the second year after planting. After harvesting during the carbon dioxide application period, once the asparagus stems have completely yellowed, they can be mowed.

[0024] Carbon dioxide application may be carried out every year from the first year after planting, every year from the second year after planting, or only in any given year.

[0025] According to the asparagus cultivation method of this aspect, by applying carbon dioxide from autumn to early winter in greenhouse long-term harvest cultivation, the asparagus yield from autumn to early winter can be improved. Since autumn to early winter is the off-season for asparagus, it is possible to meet the demand for asparagus during this off-season. Furthermore, the increase in asparagus yield from autumn to early winter due to carbon dioxide application does not reduce the sugar content of the storage roots. Therefore, it is possible to improve the yield during the off-season without reducing the yield of spring buds the following spring. The asparagus cultivation method according to this embodiment involves applying 600 to 2000 ppm of carbon dioxide during at least part of the period from autumn to early winter in greenhouse long-term harvest cultivation of asparagus, and can also be said to be a method for increasing the yield of asparagus during the off-season without reducing the yield of spring buds in the following spring. [Example]

[0026] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0027] <How to grow asparagus> The test variety used was a one-year-old Wellcome plant grown in a 30 cm pot. Except for the CO2 application period, cultivation was carried out in an unheated greenhouse.

[0028] (CO2 application area) The CO2 application area was cultivated under the following conditions. Cultivation environment: sunlight-based artificial climate room CO2 application period: October 25, 2019 ~ November 22, 2019 CO2 application time: 6:30-17:30 CO2 application concentration: 1,000ppm Temperature settings: Daytime temperature 23℃, nighttime temperature 15℃ Number of stems: 4 or 8

[0029] (CO2 non-application area) The plants were cultivated in the same manner as in the CO2 application area, except that CO2 application was not performed.

[0030] <Survey method> The following items were investigated for the CO2 application area and the non-CO2 application area. Note that the "CO2 application period" below refers to October 25, 2019 to November 22, 2019. Sugar content of storage roots before and after CO2 application period - Amount of young shoots produced during the CO2 application period Once every 4 to 5 days, young stems were collected and their dry weight was measured. Number, yield, and average weight in the following spring (2020) Young stems with a 25cm prepared weight of 5g or more were collected and measured.

[0031] <Result> Figure 1 shows the change in CO2 concentration in the sunlight-type artificial climate chamber during the CO2 application period. Table 1 shows the sugar content of storage roots before and after the CO2 application period, and the amount of young stems produced during the CO2 application period.

[0032] [Table 1]

[0033] In the CO2 application area, the sugar content of storage roots after the CO2 application period was significantly higher than in the non-CO2 application area. In addition, the number of spears and dry weight during the CO2 application period were significantly higher in the CO2 application area compared to the non-CO2 application area. However, no difference was observed due to the difference in the number of mature spears. These results confirmed that CO2 application improves autumn yields.

[0034] The number of stalks, stalk yield, and average stalk weight in the following spring are shown in Table 2.

[0035] [Table 2]

[0036] The yield in the following spring was significantly higher when the number of mature stems was eight compared to when it was four. However, no significant difference in yield in the following spring was observed between the CO2 application area and the non-CO2 application area. These results confirmed that CO2 application from autumn to winter does not affect the yield in the following spring.

[0037] These results indicate that CO2 application from autumn to early winter can increase yields during the transitional period from autumn to early winter without reducing yields in the following spring. [Industrial Applicability]

[0038] According to the present invention, there is provided a method for cultivating asparagus in a greenhouse for extended harvesting, which enables increased yield during the off-season without reducing the yield in the spring of the following year.

Claims

1. In greenhouse long-term asparagus cultivation, Applying 600 to 2000 ppm of carbon dioxide during at least a portion of autumn to early winter; The application of carbon dioxide is started in autumn, the application period of carbon dioxide is 10 days or more, the application of carbon dioxide is completed in November or December, and the application of carbon dioxide is carried out for 6 hours or more during the daytime. How to grow asparagus.

2. 2. The method for cultivating asparagus according to claim 1, wherein the period for applying carbon dioxide is 10 days or more and 60 days or less.

3. 3. The method for cultivating asparagus according to claim 1, wherein the application of carbon dioxide is carried out for 8 hours or more during the day.

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