A cultivation method for delaying the ripening of blueberry fruits

Abstract

The present invention provides a cultivation method for delaying the ripening of blueberry fruits, belonging to the technical field of blueberry cultivation. The cultivation method of the present invention comprises the following steps: starting from when the blueberry plants enter the winter dormancy period, three-stage treatments of gradually decreasing temperature, accumulating low temperature, and gradually increasing temperature are successively carried out in a semi-underground steel skeleton arch-shaped greenhouse to delay the germination time and fruit ripening time of the blueberry plants. The present invention breaks through the seasonal limitation under the semi-underground greenhouse conditions, delays the germination of blueberry flower buds and leaf buds until the entire growth period is postponed, and finally realizes the off-season listing of fresh blueberry fruits. Through the cultivation method of the present invention with low energy consumption and easy management, it not only fills the gap period in the domestic fresh blueberry fruit market, but also brings higher economic benefits to blueberry cultivation due to the off-peak listing of fresh blueberry fruits.

Description

Technical Field

[0001] The present invention relates to the technical field of blueberry cultivation, and particularly relates to a cultivation method for delaying the ripening of blueberry fruits. Background Art

[0002] Blueberries, also known as Vaccinium Spp, are shrubs of the genus Vaccinium in the family Ericaceae. Ripe blueberry fruits are blue-purple in color, with a unique fruit flavor, rich in various active substances such as anthocyanins, and have multiple effects such as antioxidant, anti-tumor, protecting eyesight, and preventing cardiovascular and cerebrovascular diseases. They are emerging fruits that are increasingly favored by the public.

[0003] With the development of protected agriculture, currently, in addition to September to October, fresh blueberries are produced and marketed throughout the year. Although there are also blueberries on the market from September to October every year, most of them are imported fresh fruits or fruits stored and preserved in the country. Whether it is imported fresh fruits or stored and preserved fruits, it not only increases the production cost, but also the nutritional components will be lost during transportation and storage, and the taste will also decline, resulting in a very poor consumer experience. In order to meet the increasingly rising consumer demand and achieve the annual production and supply of fresh blueberries, the application of the off-season planting technology for fresh blueberries is becoming more and more common. Currently, the off-season production of fresh blueberries mostly promotes the early listing of fresh blueberries under facility conditions. Due to the advantages of early maturity, high commercial rate of fresh fruits, and high market price in the off-season production of blueberries, greenhouse and cold shed cultivation has become an important planting method in the north. Under the facility conditions in the north, through measures such as heating and heat preservation, blueberries are promoted to bloom and bear fruit in advance, and the production and supply of fresh fruits in winter and early spring have been realized. However, in cold regions in the north, due to factors such as severe cold in winter and high heating costs in facility production, this production method still has problems such as poor taste, high energy consumption, and high requirements for production management. Based on this, the present invention has invented a cultivation method for delaying the ripening of blueberry fruits, which has low energy consumption and simple management, can make up for the off-season period of fresh blueberry production, and achieve the annual production and supply of fresh fruits. Summary of the Invention

[0004] The purpose of the present invention is to provide a cultivation method for delaying the ripening of blueberry fruits. The present invention breaks through the seasonal restrictions under the conditions of a semi-underground greenhouse, delays the germination of blueberry flower buds and leaf buds, and even delays the entire growth period, and finally realizes the off-season (September to October) listing of fresh blueberries. Through the cultivation method of the present invention with low energy consumption and easy management, it not only fills the off-season period of the domestic fresh blueberry market, but also brings higher economic benefits to blueberry cultivation due to the off-peak listing of fresh blueberries.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a cultivation method for delaying the ripening of blueberry fruits, which comprises the following steps: starting from the time when the blueberry plants enter the winter dormancy period, three-stage treatments of gradually decreasing temperature, accumulating low temperature, and gradually increasing temperature are successively carried out in a semi-underground steel skeleton arch-shaped greenhouse to delay the germination time and fruit ripening time of the blueberry plants;

[0007] The gradually decreasing temperature means that the air temperature in the greenhouse is decreased from 0°C to -18°C to -12°C, and the ground temperature is decreased to -15°C to -10°C, and the temperature decrease lasts for 35 to 45 days;

[0008] The accumulating low temperature means that after the air temperature in the greenhouse is decreased to -18°C to -12°C, it is accumulated in the semi-underground steel skeleton arch-shaped greenhouse for 3 to 4 months, so that the air temperature in the greenhouse at the end of the accumulating low temperature stage is 8 to 12°C, and the ground temperature is 5°C to 8°C;

[0009] The gradually increasing temperature is to gradually increase the air temperature in the greenhouse to 18 to 22°C and the ground temperature to 16°C to 24°C, and the temperature increase lasts for 35 to 45 days.

[0010] Preferably, the semi-underground steel skeleton arch-shaped greenhouse comprises a steel skeleton, a rear wall, gable walls, and a film covering, and the depth of excavation in the greenhouse is 0.8 to 1.2 m.

[0011] Preferably, the thickness of the rear wall is 0.37 m to 0.62 m and the height is 4.0 m to 4.5 m; the thickness of the gable walls is 0.37 m to 0.62 m; a heat-insulating layer with a thickness of 0.06 m to 0.12 m is added to the outer walls of the rear wall and the gable walls; the film covering is a non-drip film with a light transmittance of 85% to 95%, and a waterproof cotton felt is covered above the non-drip film.

[0012] Preferably, a set of air turbulence fans is arranged every 100 m 2 to 150 m 2 in the greenhouse.

[0013] Preferably, the variety of the blueberry plants is a late-maturing variety of northern highbush blueberries; the blueberry plants are more than 2 years old, with a plant height of ≥0.6 m, and are healthy blueberry seedlings with more than 3 branches.

[0014] Preferably, during the process of gradually decreasing temperature, the cotton felt is covered during the day and rolled up at night, and the air turbulence fans are turned on to force ventilation for 4 to 5 hours every day; when the air temperature in the greenhouse drops to -10°C, the rolling and unrolling of the cotton quilt are stopped, and the turbulence fans are turned off; thereafter, the temperature in the greenhouse continuously decreases with the external temperature until the air temperature drops to -18°C to -12°C and the ground temperature drops to -15°C to -10°C.

[0015] Preferably, during the process of accumulating low temperature, a double-layer aluminum foil heat-insulating and reflective film is covered outside the cotton felt.

[0016] Preferably, during the step-by-step heating process, after removing the double-layer aluminum foil heat-insulating reflective film, on the 1st to 3rd day, put down 3 / 4 of the cotton felt quilt at sunrise, and completely roll up the cotton felt quilt 1 hour after sunset; on the 4th to 6th day, put down 1 / 2 of the cotton felt quilt at sunrise, and completely roll up the cotton felt quilt 1 hour after sunset; on the 7th to 9th day, put down 1 / 4 of the cotton felt quilt at sunrise, and completely roll up the cotton felt quilt 1 hour after sunset; on the 10th day, completely roll up the cotton felt quilt, open the upper and lower vents for ventilation around the clock, and then turn on the air conditioning system to prevent the air from leaking. Carry out natural ventilation and cover with shade nets with a shading rate of 60-80% for 24 hours; then gradually reduce the shading time. On the 11th to 13th days, the shading time is 1 hour after sunrise to 1 hour before sunset; on the 14th to 16th days, the shading time is 2 hours after sunrise to 2 hours before sunset; on the 17th to 19th days, the shading time is 3 hours after sunrise to 3 hours before sunset; after the 20th day, the plants can adapt to the external temperature and humidity conditions and all shade nets can be removed.

[0017] The present invention provides a cultivation method for delaying the ripening of blueberry fruits. The method makes full use of natural low temperature conditions under semi-underground greenhouse conditions, breaks through seasonal restrictions, and prolongs the dormancy period of blueberries, thereby delaying the germination of blueberry flower buds and leaf buds until the entire growth period is delayed. The fruit ripening period of the blueberry plant of the present invention is from the end of August to mid-to-late September, which is 30 to 45 days later than the fruit ripening period of the conventional cultivation method, and can achieve the delayed season (September to October) listing of fresh blueberry fruits. The present method has the characteristics of low energy consumption and easy management. At the same time, the fresh blueberry fruits produced by this method have good taste and good quality because the fruit ripening period is staggered from the high temperature weather in summer and the temperature difference between day and night in autumn is large, which is conducive to the accumulation of fruit sugar and active substances. Through the method of the present invention, not only the domestic blueberry fresh fruit market gap is filled, but also the blueberry fresh fruit is staggered to the market, which brings higher economic benefits to blueberry planting. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a greenhouse in which a double layer of aluminum foil heat-insulating reflective film is added to the cotton felt blanket during the low temperature accumulation stage of the test group in Example 1.

[0019] Figure 2 This is the greenhouse after the cotton felt is completely rolled up during the step-by-step heating stage of the test group in Example 1. DETAILED DESCRIPTION

[0020] The invention provides a cultivation method for delaying the ripening of blueberry fruits, comprising the following steps: after the blueberry plants enter a winter dormancy period, three-stage treatments of step-by-step cooling, accumulating low temperatures and step-by-step heating are sequentially performed in a semi-underground steel frame arch greenhouse, so as to delay the germination time and fruit ripening time of the blueberry plants.

[0021] In the present invention, the stepwise temperature reduction preferably refers to reducing the temperature inside the greenhouse from 0°C to -18°C to -12°C, more preferably to -16°C; and reducing the ground temperature to -15°C to -10°C, more preferably to -12°C.

[0022] In the present invention, the time for the stepwise temperature reduction preferably lasts for 35 to 45 days, more preferably for 43 days.

[0023] In the present invention, the low temperature accumulation preferably means that after reducing the temperature inside the greenhouse to -18°C to -12°C, it is accumulated in a semi-underground steel skeleton arch-shaped greenhouse for 3 to 4 months, more preferably for 3.5 months.

[0024] In the present invention, at the end of the low temperature accumulation stage, the temperature inside the greenhouse is preferably 8 to 12°C, more preferably 10°C; the ground temperature is preferably 5°C to 8°C, more preferably 6.5°C.

[0025] In the present invention, the stepwise temperature increase preferably means gradually increasing the temperature inside the greenhouse to 18 to 22°C, more preferably to 20°C; and increasing the ground temperature to 16°C to 24°C, more preferably to 18.5°C.

[0026] In the present invention, the time for the stepwise temperature increase preferably lasts for 35 to 45 days, more preferably for 40 days.

[0027] In the present invention, the semi-underground steel skeleton arch-shaped greenhouse preferably includes a steel skeleton, a rear wall, gable walls, and a film covering.

[0028] In the present invention, the thickness of the rear wall is 0.37 m to 0.62 m, more preferably 0.62 m.

[0029] In the present invention, the height of the rear wall is preferably 4.0 m to 4.5 m, more preferably 4.0 m.

[0030] In the present invention, the thickness of the gable wall is 0.37 m to 0.62 m, more preferably 0.62 m.

[0031] In the present invention, preferably, a heat-insulating layer with a thickness of 0.06 m to 0.12 m is added outside the rear wall, more preferably a heat-insulating layer with a thickness of 0.1 m is added.

[0032] In the present invention, preferably, a heat-insulating layer with a thickness of 0.06 m to 0.12 m is added outside the gable wall, more preferably a heat-insulating layer with a thickness of 0.1 m is added.

[0033] In the present invention, the materials of the heat-insulating layer preferably include extruded plastic boards, polystyrene foam boards, rigid polyurethane foam heat-insulating boards, perlite cement boards, and rock wool boards, more preferably rigid polyurethane foam heat-insulating boards.

[0034] In the present invention, the film covering is preferably a drip-free film with a light transmittance of 85% to 95%, and more preferably a drip-free film with a light transmittance of 90%.

[0035] In the present invention, a waterproof cotton felt is preferably covered above the drip-free film.

[0036] In the present invention, the depth of excavation inside the greenhouse is preferably 0.8 m to 1.2 m, and more preferably 1.0 m.

[0037] In the present invention, inside the greenhouse, preferably, one set of air turbulence fans is arranged every 100 m 2 to 150 m 2 and more preferably, one set of air turbulence fans is arranged every 100 m 2 .

[0038] In the present invention, the variety of the blueberry plants is preferably a late-maturing variety of northern highbush blueberries, and more preferably the northern highbush blueberry variety: Liberty.

[0039] In the present invention, the blueberry plants are preferably blueberry seedlings over 2 years old, and more preferably 3-year-old blueberry seedlings.

[0040] In the present invention, the plant height of the blueberry seedlings is preferably ≥0.6 m, and more preferably 0.8 m.

[0041] In the present invention, the blueberry seedlings preferably have more than 3 branches.

[0042] In the present invention, before the blueberry plants enter the winter dormancy period, it preferably further includes the process of transplanting the blueberry seedlings into the semi-underground steel skeleton arch-shaped greenhouse.

[0043] In the present invention, before the transplantation, the soil inside the greenhouse is preferably improved.

[0044] In the present invention, the soil improvement preferably includes detecting the pH value of the planting soil and adjusting the pH value to 4.5 to 5.5 with sulfur powder, and more preferably adjusting the pH value to 5.0.

[0045] In the present invention, the plant spacing of the transplanted blueberry seedlings is preferably 0.8 m to 1.0 m, and more preferably 1.0 m.

[0046] In the present invention, the row spacing of the transplanted blueberry seedlings is preferably 1.2 m to 2.0 m, and more preferably 2.0 m.

[0047] In the present invention, the planting depth of the transplanted blueberry seedlings is preferably 1 cm to 2 cm higher than the original substrate surface of the blueberry plants, and more preferably 2 cm higher than the original substrate surface of the blueberry plants.

[0048] In the present invention, it is preferred to water in time after transplanting.

[0049] In the present invention, during the process of gradually decreasing the temperature, it is preferred to cover with cotton quilts during the day, roll up the cotton quilts at night, and turn on the air turbulence fan to force ventilation for 4 h to 5 h every day; when the temperature in the shed drops to -10°C, stop rolling up and putting down the cotton quilts and turn off the turbulence fan; thereafter, the temperature in the shed continuously decreases with the outside temperature until the air temperature drops to -18°C to -12°C and the ground temperature drops to -15°C to -10°C; more preferably, cover with cotton quilts during the day, roll up the cotton quilts at night, and turn on the air turbulence fan to force ventilation for 5 h every day; when the temperature in the shed drops to -10°C, stop rolling up and putting down the cotton quilts and turn off the turbulence fan; thereafter, the temperature in the shed continuously decreases with the outside temperature until the air temperature drops to -16°C and the ground temperature drops to -12°C.

[0050] In the present invention, during the process of accumulating low temperature, it is preferred to cover with a double-layer aluminum foil heat-insulating and reflective film outside the cotton quilts.

[0051] In the present invention, during the process of gradually increasing the temperature, it is preferred that after removing the double-layer aluminum foil heat-insulating and reflective film, on the 1st to 3rd days, put down 3 / 4 of the cotton quilts at sunrise and roll up all the cotton quilts completely 1 hour after sunset; on the 4th to 6th days, put down 1 / 2 of the cotton quilts at sunrise and roll up all the cotton quilts completely 1 hour after sunset; on the 7th to 9th days, put down 1 / 4 of the cotton quilts at sunrise and roll up all the cotton quilts completely 1 hour after sunset; on the 10th day, roll up all the cotton quilts completely, open the upper and lower ventilation openings for natural ventilation all day long, and at the same time cover a sunshade net with a sunshading rate of 60% to 80%, and the sunshading time is 24 h; then gradually reduce the sunshading time, on the 11th to 13th days, the sunshading time is from 1 hour after sunrise to 1 hour before sunset; on the 14th to 16th days, the sunshading time is from 2 hours after sunrise to 2 hours before sunset; on the 17th to 19th days, the sunshading time is from 3 hours after sunrise to 3 hours before sunset; after the 20th day, the plants can adapt to the external temperature and humidity conditions, and remove all the sunshade nets.

[0052] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0053] Example 1

[0054] Select a robust northern highbush late-ripening blueberry variety - Liberty that is 3 years old, 0.8 m in plant height, and has 3 to 5 branches.

[0055] Construct a semi-underground steel frame arch-shaped greenhouse: The thickness of the rear wall is 0.37 m and the height is 4.0 m. The thickness of the gable wall is 0.37 m. A 0.1 m thick rigid polyurethane foam insulation board is added to the outer walls of the rear wall and the gable wall. The greenhouse frame material is galvanized steel pipe. Cover with a non-drip film with a light transmittance of 90%, and cover the film with a waterproof cotton felt. Dig 1.0 m underground. Detect the pH value of the soil in the planting greenhouse and adjust the pH value to 5.0 with sulfur powder. Every 100 m in the greenhouse 2 Set up a group of air turbulence fans.

[0056] Randomly divide the selected free blueberry seedlings into two groups on average. One group is the experimental group and the other group is the control group.

[0057] The blueberries in the experimental group are planted in the above-mentioned semi-underground steel frame arch-shaped greenhouse according to the planting density of 1.0 m in plant spacing and 2.0 m in row spacing. The planting depth is that the planting soil surface is 2 cm higher than the original substrate surface of the blueberry plants. Water in time after planting and carry out the following experimental treatments: After the blueberry plants enter the dormant period, starting from when the temperature in the greenhouse drops to 0 °C, carry out three stages of treatment: step-by-step cooling, low temperature accumulation, and step-by-step warming.

[0058] First, enter the step-by-step cooling stage: Cover the greenhouse with cotton felt during the day and roll up the cotton felt at night, and turn on the air turbulence fans to force ventilation for 5 h every day. Use the natural low temperature in winter in the north to gradually reduce the temperature in the greenhouse from the initial temperature of 0 °C to -10 °C, then stop rolling and unrolling the cotton quilt, and turn off the turbulence fans; After that, the temperature in the greenhouse continues to drop with the outside temperature until the air temperature drops to -16 °C and the ground temperature drops to -12 °C (the lowest meteorological temperature throughout the year). The step-by-step cooling stage lasts for 43 days.

[0059] Then enter the low temperature accumulation stage: At this time, the blueberry plants are still in the dormant period. Cover the outside of the cotton felt with a double-layer aluminum foil heat-insulating and reflective film (as Figure 1 shown), which can not only reflect sunlight but also prevent heat conduction inside and outside the greenhouse. After that, the temperature in the greenhouse will gradually rise with the outside temperature, but the warming speed is slower than that of normal greenhouses and open fields; When the air temperature in the greenhouse rises to 10 °C and the ground temperature rises to 6.5 °C, the low temperature accumulation stage lasts for 3.5 months.

[0060] At this time, the blueberry plants begin to germinate and enter the step-by-step warming stage: In the first step, remove the double-layer aluminum foil heat-insulating and reflective film after sunset. On the 1st - 3rd days, put down 3 / 4 of the cotton felt at sunrise and roll up the cotton felt completely 1 h after sunset; On the 4th - 6th days, put down 1 / 2 of the cotton felt at sunrise and roll up the cotton felt completely 1 h after sunset; On the 7th - 9th days, put down 1 / 4 of the cotton felt at sunrise and roll up the cotton felt completely 1 h after sunset; On the 10th day, roll up the cotton felt completely (as Figure 2As shown in the figure, open the upper and lower vents for natural ventilation all day long, and at the same time cover the shed film with a sunshade net with a sunshading rate of 60% for 24 hours; from the 11th to the 13th day, the sunshading time is from 1 hour after sunrise to 1 hour before sunset; from the 14th to the 16th day, the sunshading time is from 2 hours after sunrise to 2 hours before sunset; from the 17th to the 19th day, the sunshading time is from 3 hours after sunrise to 3 hours before sunset; after the 20th day, the plants can adapt to the external temperature and humidity conditions, and all sunshade nets are removed. On the 40th day, the air temperature in the greenhouse rises to 20 °C, and the ground temperature rises to 18.5 °C. During this stage, the blueberry plants have experienced physiological changes from the germination of flower buds and leaf buds to the unfolding of leaves and the initial flowering.

[0061] After being treated in three stages, the blueberry plants enter the conventional production management, including: 1. Flowering stage management: Release bees when seeing flowers (1 box of bumblebees per mu); Keep the soil moist (soil water content 60% - 70%); Prevent and control pests and diseases; 2. Fruit development stage management: Keep the soil moist (soil water content 60% - 70%), avoid watering a large amount of water after severe water shortage; Combine tillage to carry out manual weeding; Prevent and control pests and diseases; 3. Fruit maturity stage management: Water in a timely manner, drain water in a timely manner, and pick in a timely manner; 4. Post-harvest management: Prune in a timely manner, control water (control the soil water content at 40% - 50%); 5. Defoliation stage management: Clean the orchard in a timely manner, water the frozen water, and prepare winter materials; 6. Dormancy stage management: Check and maintain various facilities in the greenhouse.

[0062] The control group of blueberries was planted in the above semi-underground steel skeleton arch-shaped greenhouse according to the planting density of 1.0 m in plant spacing and 2.0 m in row spacing. The planting depth was that the planting soil surface was 2 cm higher than the original substrate surface of the blueberry plants. Water was applied in a timely manner after planting, and then conventional production management was carried out. The control group of blueberries entered the dormancy period at the same time as the experimental group of blueberries, but did not undergo the step-by-step cooling stage treatment of covering with cotton felt during the day, rolling up the cotton felt at night, and turning on the air turbulence fan for forced ventilation; nor did it undergo the stage treatment of accumulating low temperature by laying a double-layer aluminum foil heat-insulating and reflective film and the step-by-step warming stage treatment of gradually rolling up the quilt and gradually reducing the sunshading time.

[0063] Record the phenological periods of the two groups of blueberries. Spring germination period: For the control group of blueberries, it was April 17th, and for the experimental group of blueberries, it was May 15th; Initial flowering period: For the control group of blueberries, it was May 9th, and for the experimental group of blueberries, it was June 16th; Fruit maturity period: For the control group of blueberries, it was from July 15th to August 11th, and for the experimental group of blueberries, it was from August 24th to September 27th. The picking period of the experimental group was on average 43.5 days later than that of the control group.

[0064] Example 2

[0065] This example explored the influence of the duration of low temperature on the germination time and fruit maturity time of blueberries. The specific process is as follows:

[0066] Select a 3-year-old, 0.8 m tall, and robust late-maturing northern highbush blueberry variety - Liberty with 3 to 5 branches. The planting conditions (semi-underground steel skeleton arch-shaped greenhouse, planting density, planting depth, transplanting time) are the same as those of the experimental group and the control group in Example 1. After the blueberry plants enter the dormant period, they are treated in three stages: gradually decreasing temperature, accumulating low temperature, and gradually increasing temperature. During the treatment in the stage of accumulating low temperature, do not cover a double-layer aluminum foil heat-insulating and reflective film outside the cotton quilt. After the temperature inside the greenhouse rises to 10 °C and the ground temperature rises to 7.2 °C, enter the stage of gradually increasing temperature, and then carry out conventional growth management as in Example 1 until the fruits are ripe and picked.

[0067] Record its phenological period. Spring sprouting period: May 2nd; initial flowering period: May 27th; fruit maturity period: July 25th - August 14th.

[0068] It can be seen from this example that although the greenhouse blueberries are treated in three stages of gradually decreasing temperature, accumulating low temperature, and gradually increasing temperature, no double-layer aluminum foil heat-insulating and reflective film is laid in the stage of accumulating low temperature. Lack of the barrier of the aluminum foil heat-insulating and reflective film to direct sunlight, the temperature inside the greenhouse rises relatively fast, and the duration of low temperature is less than that of the experimental group. Compared with the control group, the spring germination time is delayed by 13 days, but the delay time is less than that of the experimental group. The final picking period is delayed by an average of 6.5 days compared with the control group, while the picking period of the experimental group is delayed by an average of 43.5 days compared with the control group.

[0069] Example 3

[0070] This example explores the influence of the cultivation environment temperature on the blueberry germination time and fruit maturity time. The specific process is as follows:

[0071] Select a 3-year-old, 0.8 m tall, and robust late-maturing northern highbush blueberry variety - Liberty with 3 to 5 branches. The planting conditions (semi-underground steel skeleton arch-shaped greenhouse, planting density, planting depth, transplanting time) are the same as those of the experimental group and the control group in Example 1. After the blueberry plants enter the dormant period, do not carry out the treatment of gradually decreasing temperature by covering the cotton quilt during the day, rolling up the cotton quilt at night and turning on the air turbulence fan for forced ventilation. The temperature inside the greenhouse drops naturally with the outside air temperature. When the annual meteorological temperature is the lowest, the temperature inside the greenhouse drops to -9.8 °C and the ground temperature drops to -2.6 °C; carry out the treatment of accumulating low temperature by laying a double-layer aluminum foil heat-insulating and reflective film; but do not carry out the treatment of gradually rolling up the quilt and gradually reducing the shading time in the stage of gradually increasing temperature. After the temperature inside the greenhouse rises to 10 °C, choose a cloudy day to directly remove the aluminum foil heat-insulating and reflective film and roll up the cotton quilt, and then carry out conventional growth management as in Example 1 until the fruits are ripe and picked.

[0072] Record its phenological period. Spring sprouting period: April 25th; initial flowering period: May 18th; fruit maturity period: July 19th - August 12th.

[0073] It can be seen from this embodiment that the blueberries in the greenhouse have not been treated by artificial step-by-step cooling. When the meteorological temperature is the lowest throughout the year, neither the air temperature nor the ground temperature in the greenhouse can reach the ideal low temperature state. Although a double-layer aluminum foil heat-insulating and reflective film is laid for low temperature accumulation treatment afterwards, the low temperature state still cannot be effectively maintained. Moreover, after the temperature rises, the step-by-step heating treatment method is not adopted. Instead, the aluminum foil heat-insulating and reflective film is directly removed on cloudy days, and the cotton quilt is rolled up. Eventually, the germination time of blueberry plants in spring cannot be effectively delayed, nor can the ripening and listing time of blueberries be delayed.

[0074] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A cultivation method for delaying the ripening of blueberry fruits, characterized in that, It includes the following steps: Starting from the winter dormancy period of the blueberry plants, three stages of treatment, namely step-by-step cooling, low temperature accumulation, and step-by-step warming, are successively carried out in a semi-underground steel skeleton arch-shaped greenhouse to delay the germination time and fruit ripening time of the blueberry plants; The step-by-step cooling means that the air temperature in the greenhouse is reduced from 0 °C to -18 °C to -12 °C, and the ground temperature is reduced to -15 °C to -10 °C, and the cooling time lasts for 35 to 45 days; The low temperature accumulation means that after the air temperature in the greenhouse is reduced to -18 °C to -12 °C, it is accumulated in the semi-underground steel skeleton arch-shaped greenhouse for 3 to 4 months, so that the air temperature in the greenhouse at the end of the low temperature accumulation stage is 8 to 12 °C, and the ground temperature is 5 °C to 8 °C; The step-by-step warming is to gradually raise the air temperature in the greenhouse to 18 to 22 °C and the ground temperature to 16 °C to 24 °C, and the warming time lasts for 35 to 45 days.

2. The cultivation method according to claim 1, characterized in that, The semi-underground steel skeleton arch-shaped greenhouse includes a steel skeleton, a rear wall, gable walls, and a film covering. The depth of excavation in the greenhouse is 0.8 to 1.2 m.

3. The cultivation method according to claim 2, characterized in that, The thickness of the rear wall is 0.37 m to 0.62 m, and the height is 4.0 m to 4.5 m; the thickness of the gable wall is 0.37 m to 0.62 m; a heat insulation layer with a thickness of 0.06 m to 0.12 m is added to the outer walls of the rear wall and the gable walls; the film covering is a non-drip film with a light transmittance of 85% to 95%, and a waterproof cotton felt is covered above the non-drip film.

4. The cultivation method according to claim 3, characterized in that, Set a group of air spoiler fans every 100 m 2 ~150 m 2 inside the greenhouse.

5. The cultivation method according to claim 4, wherein The variety of the blueberry plants is a late-maturing variety of northern highbush blueberries; the blueberry plants are more than 2 years old, with a plant height of ≥ 0.6 m, and are healthy blueberry seedlings with more than 3 branches.

6. The cultivation method according to claim 5, characterized in that, During the process of step-by-step cooling, the cotton felt is covered during the day and rolled up at night, and the air turbulence fan is turned on to force ventilation for 4 to 5 hours every day; when the air temperature in the greenhouse drops to -10 °C, the rolling of the cotton felt is stopped, and the turbulence fan is turned off; thereafter, the temperature in the greenhouse continues to drop with the outside temperature until the air temperature drops to -18 °C to -12 °C and the ground temperature drops to -15 °C to -10 °C.

7. The cultivation method according to claim 6, wherein, During the process of low temperature accumulation, a double-layer aluminum foil heat insulation and reflective film is covered outside the cotton felt.

8. The cultivation method according to claim 7, wherein During the process of step-by-step warming, after removing the double-layer aluminum foil heat insulation and reflective film, on the 1st to 3rd days, 3 / 4 of the cotton felt is put down at sunrise and completely rolled up 1 hour after sunset; on the 4th to 6th days, 1 / 2 of the cotton felt is put down at sunrise and completely rolled up 1 hour after sunset; on the 7th to 9th days, 1 / 4 of the cotton felt is put down at sunrise and completely rolled up 1 hour after sunset; on the 10th day, the cotton felt is completely rolled up, the upper and lower ventilation openings are opened for natural ventilation all day long, and at the same time, a sunshade net with a sunshade rate of 60 to 80% is covered, and the sunshade time is 24 hours; then the sunshade time is gradually reduced. On the 11th to 13th days, the sunshade time is from 1 hour after sunrise to 1 hour before sunset; on the 14th to 16th days, the sunshade time is from 2 hours after sunrise to 2 hours before sunset; on the 17th to 19th days, the sunshade time is from 3 hours after sunrise to 3 hours before sunset; after the 20th day, the plants can adapt to the external temperature and humidity conditions, and all the sunshade nets are removed.

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