A method for creating a pink asparagus

Abstract

The application discloses a kind of creation method of pink asparagus, it is related to the technical field of asparagus planting, comprising the following steps: step one, variety selection: selecting stable anthocyanin synthesis, strong heat resistance purple asparagus variety;Step two, cultivation management;Step three, film management: set up conventional greenhouse, rectangular small arched shed, cover black and white bicolour mulch with 0, thickness 8-12 silk light transmittance, initial state black film surface up, white film surface down, film edge compaction, drip irrigation belt is placed between ditch;Step four, light temperature regulation: when the day and night temperature in greenhouse is continuously 15℃-28℃, black and white bicolour mulch is turned to white film up, black film down;Step five, harvesting management;Step six, mother stem remains to keep.The application, by decoupling light and temperature control of external greenhouse and internal small arched shed, in combination with film surface turning and micropore design, to realize the regulation of asparagus light and temperature in small arched shed, keep the pink expression of internal purple asparagus.

Description

Technical Field

[0001] This invention relates to the field of asparagus cultivation technology, specifically to a method for creating pink asparagus. Background Technology

[0002] Asparagus is one of the world's top ten famous vegetables, rich in anthocyanins, selenium, and other active ingredients. Currently, the main commercial varieties are green and purple asparagus, with purple asparagus giving it its purple color due to its high anthocyanin content. In recent years, market demand for rarer colored asparagus (such as pink) has increased, but the cultivation of pink asparagus faces the following technical bottlenecks:

[0003] Uncontrolled light and temperature coupling: Traditional single-layer greenhouses cannot separate light and temperature control. While transparent film (light transmittance > 80%) can control temperature, it induces chlorophyll synthesis, causing asparagus to appear green; black film (heat absorption rate > 95%) can block light, but it causes the temperature inside the greenhouse to exceed 35°C, activating anthocyanin-degrading enzymes and causing the purple color to fade.

[0004] Poor varietal adaptability: Anthocyanin synthesis in common purple asparagus is unstable, and the activity of anthocyanin-degrading enzymes increases at high temperatures (>30℃), leading to fading.

[0005] Excessive operational disturbance: The removal of the film during the harvest period caused sudden changes in temperature and humidity, resulting in anthocyanin concentration fluctuations exceeding 40%.

[0006] The aforementioned shortcomings led to the failure of pink asparagus industrialization, and there is currently no stable mass production solution in the industry. Therefore, there is an urgent need for a method that can decouple light and temperature control and achieve stable pink color expression. This invention cultivates asparagus in a double-layer greenhouse, precisely controlling the light and temperature environment of purple asparagus to ultimately produce unique pink asparagus. Pink asparagus combines the sweetness of purple asparagus with the crispness of white asparagus. Its robust and uniform shape and sweet and delicious taste are unique among asparagus varieties. At the same time, pink asparagus not only enriches the variety of agricultural products on the market, but also has a better appearance. Summary of the Invention

[0007] One of the objectives of this invention is to provide a method for creating pink asparagus by dynamically controlling anthocyanin metabolism through photothermal decoupling. The method uses a double-layer greenhouse structure to decouple light and temperature control, combined with a membrane flipping mechanism and a microporous airflow system, to directionally maintain anthocyanin concentration in the range of 0.2-0.5 mg / gFW, thereby stably expressing the pink trait that combines the sweetness of purple asparagus with the crispness of white asparagus. This breaks through the technical bottleneck of traditional cultivation and enables the mass production of pink asparagus.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for creating pink asparagus, comprising the following steps:

[0009] Step 1: Variety Selection: Select purple asparagus varieties with stable anthocyanin synthesis and strong heat resistance. Common asparagus comes in green and purple varieties. Green asparagus cannot be cultivated to pink, while purple asparagus can. However, purple asparagus varieties are extremely rare and exhibit different traits. Some purple varieties are not heat-resistant, showing unstable purple expression, which directly affects the pink color when cultivating pink asparagus from purple. Therefore, we need to select purple asparagus that is heat-resistant and has stable purple expression. The preferred purple asparagus variety is Purple Passion, whose anthocyanin synthesis gene expression level is higher than that of ordinary purple asparagus, and its heat resistance threshold is also higher. This ensures stable coloring even at high temperatures within the multi-membrane covering, thus enabling targeted cultivation of pink expression. (Studies have found that the total anthocyanin content of different purple asparagus varieties varies by 2–3 times (e.g., Purple Passion typically contains >200 mg / kg, while ordinary varieties contain approximately 50–100 mg / kg).

[0010] Step 2, Cultivation and Management: After clearing the garden, dig ditches and apply 1000±50 kg / mu of well-rotted organic fertilizer. The ditches should be 20-30 cm deep and 30-40 cm wide.

[0011] Step 3, Mulching Management: First, set up a regular greenhouse, then build a small arched shed inside the greenhouse, and cover it with black and white mulch film. Initially, if the ambient temperature is ≤15℃, the black film should face up and the white film should face down. The black film facing up enhances heat absorption, raising the temperature inside the small arched shed by 5-8℃ (actually measured temperature inside the shed can reach 20-25℃). The white film facing down reflects internal diffused light, providing weak light and avoiding complete darkness that could lead to physiological problems.

[0012] Anthocyanin synthase (ANS) has the best activity at 15-25℃, especially at 20℃, thus maintaining anthocyanin synthase activity ≥45 U / g FW, promoting anthocyanin synthesis, and increasing anthocyanin concentration to 0.2-0.5 mg / g FW.

[0013] The edges of the film are compacted, and the drip irrigation tape is placed between the ditches. If the drip irrigation tape is placed on the bed surface when supplementing water and fertilizer, water will enter the film and increase the humidity inside the film. Placing it between the ditches can supplement the field water and supplement the roots nutrients normally.

[0014] Among them, the small arched shed is a rectangular small arched shed more than 50cm away from the bed surface. The specifications of the black and white double-color mulch film are that the light transmittance is 0 and the thickness is 8-12 mil. The black and white double-color film is chosen because the temperature is low in the early stage of planting (generally in the early spring season) and the duration of sunlight is short. With the black film on top and the white film on the bottom, it can absorb sunlight to increase the temperature and promote early germination. The white inside can appropriately supplement the early spring sunlight and help the pink coloring.

[0015] Among them, the greenhouse uses hot-dip galvanized thin-walled steel pipes as the frame material. The single steel frame arched greenhouse is generally 8m or 6m wide and the length should not exceed 60m. The number of connected steel frame greenhouses should not exceed 10. The frame strength meets the local requirements for wind and snow resistance of agricultural greenhouses.

[0016] The top of the greenhouse frame is covered with a multi-functional greenhouse film with a thickness of 0.06mm-0.08mm and a film width of 2.0m-3.0m plus the width of the greenhouse. The skirt film is 0.06mm-0.08mm thick.

[0017] Step 4, Light and Temperature Control: During planting, as the air temperature rises, the temperature inside the greenhouse and the small arched sheds will rise synchronously. If the temperature inside the greenhouse remains within the range of 15℃-28℃ for at least one day and night, the mulch film needs to be turned over so that the white side faces upward to reflect sunlight, reducing the temperature inside the small arched shed by 3-5℃ and preventing the asparagus from turning yellow due to excessive temperature. The black side faces downward to insulate against ground radiation heat and reduce heat accumulation.

[0018] This is because the activity of anthocyanin-degrading enzyme (PPO) increases dramatically at temperatures above 25°C, leading to the decomposition of anthocyanins. Lowering the temperature inhibits the activity of anthocyanin-degrading enzyme (PPO) in asparagus within the small greenhouse to ≤15U / gFW, thus slowing down anthocyanin degradation and maintaining the anthocyanin concentration in the range of 0.2-0.5mg / gFW. This preserves the "pink" color of the asparagus and prevents it from turning yellow due to excessively high temperatures.

[0019] When the temperature inside the greenhouse exceeds 28℃, open the greenhouse side window ventilation system to ensure that the temperature inside the small arched shed does not exceed 33℃. Since there is a temperature difference between the greenhouse and the small arched shed, which is generally 4℃-7℃, and because the small arched shed is easy to ventilate and let in light, in order to avoid the temperature inside the small arched shed being too high, it is necessary to ventilate and cool the inside of the greenhouse to reduce the temperature inside the small arched shed.

[0020] Step 5, Harvesting Management: When asparagus enters the harvesting period, evenly distribute 90-125 micro-holes per square meter on the black and white double-sided plastic film. The micro-hole diameter is 1-2mm. This is because the outside temperature is generally high at this time of planting. By setting micro-holes, we can avoid the temperature inside the small arched greenhouse from getting too high, maintain the O2 / CO2 balance inside the greenhouse, stabilize the humidity, maintain micro-airflow without destroying the light-blocking environment, and strictly control the light transmittance to below 5%.

[0021] Every morning or evening, the black and white plastic film is removed to harvest the pink asparagus. After harvesting, the black and white plastic film is restored in time to avoid large temperature fluctuations inside the film and to prevent the pink asparagus from being exposed to excessive sunlight.

[0022] Step Six: Mother Stem Retention: After harvesting, remove the film to allow the plant to enter the vegetative growth period.

[0023] Preferably, in step three, the black side of the black-and-white mulch film has an absorption rate of ≥95% and a reflectance of ≥80% on the white side.

[0024] Preferably, in step three, if the ambient temperature is below -2℃, straw mats, non-woven fabrics, or other coverings must be added to the small arched sheds inside the greenhouse for frost protection and insulation to ensure that the temperature inside the small arched sheds is not lower than 5℃.

[0025] Preferably, the composted organic fertilizer in step two is a mixture of cow and sheep manure and soybean meal in a ratio of 7:3, with a C / N ratio of 25-30 and a pH of 6.8-7.2.

[0026] Preferably, in step five, the harvesting period is more than 60 days, and the harvesting period is gradually extended according to the age of the bamboo shoots. During this period, the temperature inside the black and white plastic film is kept below 33°C and the air humidity is kept below 65%.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) This invention adopts a double-layer design of an external greenhouse and an internal small arched greenhouse, which completely decouples light and temperature control: the external greenhouse regulates the macro environment through a side window ventilation system (response > 28℃ high temperature), while the internal small arched greenhouse uses a black and white double-color film with 0 light transmittance to block light. Combined with dynamic film flipping technology (black side facing up to absorb heat and increase temperature during low temperature period, white side facing up to reflect and reduce temperature during high temperature period), the temperature fluctuation range of the small arched greenhouse is successfully compressed from ±10℃ in traditional planting to ±3℃. This breakthrough design keeps the anthocyanin concentration stably maintained in the ideal pink range of 0.2-0.5mg / g FW, fundamentally solving the fading problem caused by light and temperature coupling in single-layer greenhouse structures.

[0029] (2) This invention establishes a temperature-triggered film flipping mechanism: when the ambient temperature is ≤15℃, the black film side facing upwards significantly increases the soil temperature by 3-5℃, activating anthocyanin synthase; when the temperature rises to 15-28℃, the white film side facing upwards reflects solar radiation, effectively inhibiting degradation enzymes. This technology breaks the vicious cycle of positive feedback of light and heat in traditional planting, significantly improving the efficiency of anthocyanin synthesis, achieving a breakthrough in pink color retention rate under high temperature conditions of 28-33℃, and expanding the stable range of enzyme activity.

[0030] (3) During the harvesting period, the present invention opens 90-125 micropores with a diameter of 1-2 mm per square meter, which can form a stable airflow, maintain the O2 / CO2 balance in the greenhouse, stabilize the humidity, reduce the germination rate of fungal spores, and extend the harvesting period to more than 60 days. At the same time, it can always strictly control the light transmittance to below 5%, which is lower than the light threshold for anthocyanin synthesis, and significantly improve the commercial rate.

[0031] (4) This invention strictly limits the film removal operation to the early morning / evening period when the light intensity is <20klux, to avoid photo-oxidative damage. Combined with the rapid restoration of the film surface within 30 minutes and the pre-set micropores, the temperature and humidity fluctuations are suppressed within ±5%, reducing the anthocyanin concentration fluctuation and the cracking rate of the bamboo shoots, increasing the proportion of high-quality bamboo shoots, and completely solving the quality deterioration problem caused by traditional harvesting operations. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating the steps of a method for creating pink asparagus according to the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1: This embodiment of the invention provides a method for creating pink asparagus, comprising the following steps:

[0035] Step 1: Variety Selection: Select a purple asparagus variety with stable anthocyanin synthesis and strong heat resistance. Conventional asparagus comes in green and purple varieties. Green asparagus cannot be cultivated into pink, while purple asparagus can. However, purple asparagus varieties are extremely rare and exhibit different traits. Some purple varieties are not heat-resistant, showing unstable purple expression, which directly affects the pink color presentation when cultivating pink asparagus from purple asparagus. Therefore, we need to select purple asparagus that is heat-resistant and has stable purple expression. The preferred purple asparagus variety is Purple Passion, whose anthocyanin synthesis gene expression level is higher than that of ordinary purple asparagus, and its heat resistance threshold is also higher. This ensures that coloring remains stable even at high temperatures within the multi-membrane covering, thus enabling targeted cultivation of pink expression.

[0036] Step 2, Cultivation and Management: After clearing the garden, dig ditches and apply 1000 kg / mu of well-rotted organic fertilizer. The ditches should be 20 cm deep and 30 cm wide.

[0037] In step two, the composted organic fertilizer is a mixture of cow and sheep manure and soybean meal in a ratio of 7:3, with a C / N ratio of 25 and a pH of 6.8.

[0038] Step 3, Mulching Management: First, set up a regular greenhouse, then build a small arched shed inside the greenhouse, and cover it with black and white mulch film. Initially, if the ambient temperature is ≤15℃, the black film should face up and the white film should face down. The black film facing up enhances heat absorption, raising the temperature inside the small arched shed by 5-8℃ (actually measured temperature inside the shed can reach 20-25℃). The white film facing down reflects internal diffused light, providing weak light and avoiding complete darkness that could lead to physiological problems.

[0039] Anthocyanin synthase (ANS) has the best activity at 15-25℃, especially at 20℃, thus maintaining anthocyanin synthase activity ≥45 U / g FW, promoting anthocyanin synthesis, and increasing anthocyanin concentration to 0.2-0.5 mg / g FW.

[0040] The edges of the film are compacted, and the drip irrigation tape is placed between the ditches. If the drip irrigation tape is placed on the bed surface when supplementing water and fertilizer, water will enter the film and increase the humidity inside the film. Placing it between the ditches can supplement the field water and supplement the roots nutrients normally.

[0041] Among them, the small arched shed is a rectangular small arched shed more than 50cm away from the bed surface. In this embodiment, the thickness of the black and white double-color mulch film is 8 mils and the light transmittance is 3%. This black and white double-color film is chosen because the temperature is low in the early stage of planting (generally in the early spring season) and the duration of sunlight is short. The black film on top can absorb sunlight to increase the temperature and promote early germination. The white film on the bottom can appropriately supplement the early spring sunlight and help the pink coloring.

[0042] Among them, the black and white dual-color mulch film with a thickness of 8 mil has a light absorption rate of ≥95% on the black side and a reflectance of ≥80% on the white side;

[0043] If the ambient temperature is below -2℃, straw mats, non-woven fabrics, or other coverings must be added to the small arched sheds inside the greenhouse for frost protection and insulation to ensure that the temperature inside the small arched sheds is not lower than 5℃.

[0044] The greenhouses use hot-dip galvanized thin-walled steel pipes and other materials as frame materials. The width of a single steel frame arched greenhouse is 6m and the length does not exceed 60m. The number of connected steel frame greenhouses does not exceed 10. The strength of the frame meets the local requirements for wind and snow resistance of agricultural greenhouses.

[0045] The top of the greenhouse frame is covered with a multi-functional greenhouse film, which is 0.07mm thick and the width of the film is the width of the greenhouse plus 2.0m. The skirt film is 0.06mm thick.

[0046] Step 4, Light and Temperature Control: During planting, as the air temperature rises, the temperature inside the greenhouse and the small arched sheds will rise synchronously. If the temperature inside the greenhouse remains within the range of 15℃-28℃ for at least one day and night, the mulch film needs to be turned over so that the white side faces upward to reflect sunlight, reducing the temperature inside the small arched shed by 3-5℃ and preventing the asparagus from turning yellow due to excessive temperature. The black side faces downward to insulate against ground radiation heat and reduce heat accumulation.

[0047] Meanwhile, the activity of anthocyanin-degrading enzyme (PPO) increases dramatically at temperatures above 25°C, leading to the decomposition of anthocyanins. Lowering the temperature inhibits the activity of anthocyanin-degrading enzyme (PPO) in asparagus within the small greenhouse to ≤15U / gFW, thus slowing down anthocyanin degradation and maintaining the anthocyanin concentration in the range of 0.2-0.5mg / gFW, preserving the "pink" color of the asparagus.

[0048] When the temperature inside the greenhouse exceeds 28℃, open the ventilation system of the greenhouse side windows to ensure that the temperature inside the small arched shed does not exceed 33℃. Since there is a temperature difference between the greenhouse and the small arched shed, which is generally 4℃-7℃, and because the small arched shed is easy to ventilate and let in light, in order to avoid the temperature inside the small arched shed being too high, it is necessary to ventilate and cool the inside of the greenhouse to reduce the temperature inside the small arched shed.

[0049] Step 5, Harvesting Management: When asparagus enters the harvesting period, 100 micro-holes of 1-2mm diameter are evenly distributed per square meter on the black and white plastic film. This is because as the outside temperature rises, setting micro-holes can prevent the temperature inside the small arched greenhouse from getting too high, maintain the O2 / CO2 balance inside the greenhouse, stabilize the humidity, and at the same time maintain micro-airflow without destroying the light-blocking environment, strictly controlling the light transmittance to below 5%.

[0050] Pink asparagus should be harvested in the early morning or evening after the black and white plastic film is removed. After harvesting, the film should be restored in time to avoid large temperature fluctuations inside the film and to prevent the pink asparagus from being exposed to excessive sunlight.

[0051] Meanwhile, because plastic film has poor air permeability and high humidity inside the greenhouse, there is no water vapor accumulating on the white film in the morning, while there is water vapor accumulating on the black film in the morning. When the film is opened, there is white vapor. Therefore, the flipping operation of the black and white film is also beneficial for the harvesting of pink asparagus.

[0052] The harvesting period is over 60 days, and the harvesting period is gradually extended according to the age of the bamboo shoots. During this period, the temperature inside the black and white plastic film should not exceed 33℃ and the air humidity should not exceed 65%.

[0053] Step Six: Mother Stem Retention: After harvesting, remove the film to allow the plant to enter the vegetative growth period.

[0054] Example 2: The only difference between this example and Example 1 is the thickness of the black and white mulch film used. In this example, a black and white mulch film with a thickness of 12 mils is used.

[0055] Example 3: The only difference between this example and Example 1 is the thickness of the black and white mulch film used. In this example, a black and white mulch film with a thickness of 14 mils is used.

[0056] Comparative Example 1: The difference between this comparative example and Example 1 is that the thickness of the black and white mulch film used is different. In this comparative example, a variety of black and white mulch films of different thicknesses are used.

[0057] Table 1 shows the film thickness and transmittance of different control groups in Examples 1-3 and Comparative Example 1.

[0058]

[0059] Table 2 shows the color representation of different groups in Table 1.

[0060]

[0061] Based on the experimental results, the color change is mainly affected by light and temperature. Under light conditions, purple asparagus synthesizes chlorophyll and anthocyanins, even with some natural light. Without light, anthocyanin synthesis decreases, the color gradually fades, and the color intensity weakens. Therefore, a plastic film with extremely low light transmittance and a thickness of ≥8 mils is needed to induce the purple asparagus to change color to pink. Besides blocking natural light, the plastic film also provides insulation. When the thickness reaches 16 mils, the temperature inside the greenhouse can easily become too high, inhibiting pigment synthesis and accelerating degradation, leading to fading and yellowing, with the pink color becoming lighter until it turns yellow or white. Although a 14-mil black and white bicolor film can meet the requirements, considering that thicker plastic films are more expensive, 8-12 mils is recommended.

[0062] Comparative Example 2: In this comparative example, the only difference from Example 1 above is that a green and white two-color mulch film with a thickness of 12 mils is used. The film covering method is the same as in Example 1, with the green side facing up in the early stage and the white side facing up in the later stage.

[0063] Comparative Example 3: In this comparative example, the only difference from Comparative Example 2 above is the method of covering the green and white mulch film, which is always white side up.

[0064] Comparative Example 4: In this comparative example, the difference from Comparative Example 2 above is that the green and white mulch film is applied differently, with the green side always facing up.

[0065] Comparative Example 5: In this comparative example, the only difference from Example 1 above is the use of a transparent 12-filament film (conventional use).

[0066] Table 3 shows the differences in mulch film color, light transmittance, and mulching method between Example 1 and Comparative Examples 2-5.

[0067]

[0068] Table 4 shows the experimental results of color performance and average yield per mu for the corresponding groups in Table 1.

[0069]

[0070] The experimental results show that the green film in the green-white bicolor mulch reduces chlorophyll synthesis, causing the weaker purple shoots and scales to turn pink. However, anthocyanin synthesis is not significantly inhibited, so the purple asparagus only becomes lighter in color and does not turn pink. The heat absorption effect of the green film is not as good as that of the black film, resulting in a slow temperature rise in the greenhouse in the early stage. Therefore, the black-white bicolor mulch is preferred, and during the planting process, the black side should be facing up in the early stage and the white side should be facing up in the later stage.

[0071] Comparative Example 6: In this comparative example, the only difference from Example 1 above is the difference in the pore density in step five.

[0072] Table 5 shows the setups for Example 1 and control groups with different micropore densities.

[0073]

[0074] Table 6 shows the test results for each group corresponding to Table 5.

[0075]

[0076] Data analysis: The experimental results in Table 6 above show that only control group 1 and example 1 achieved a yield of more than 3.00 kg / d per mu. However, as the micropore density / diameter increased, the light transmittance and air permeability increased, but the heat retention decreased. The early yield increase effect was poor, but the color was stable in the later stage, the disease incidence was low, and the marketability was good. However, when there was too much light transmission, especially with large-diameter holes, the asparagus color was light purple instead of pink.

[0077] Considering both the proportion of asparagus powder and marketability, the optimal result is 100 micropores per square meter (with a pore diameter of about 1-2 mm) on both black and white double-layer films.

[0078] Comparative Example 7: The difference between this comparative example and Example 1 above is the different coating method. In this comparative example, the white side is always facing up.

[0079] Comparative Example 8: The difference between this comparative example and Example 1 above is the coating method. In this comparative example, the black side is always facing up.

[0080] Table 7 shows the differences in the coating methods between Example 1 and Comparative Examples 7 and 8.

[0081]

[0082] Table 8 shows the experimental results corresponding to the different coating methods in Table 7.

[0083]

[0084] The experimental results show that in the early stage of asparagus germination, the black plastic film has the effect of shading and heat preservation, resulting in a large number of asparagus germinations. If the white film faces upward, the temperature inside the greenhouse will rise too slowly, resulting in low yield. Later, when the temperature rises, the black film absorbs light, and the highest temperature inside the greenhouse can reach 40℃, thus affecting the production of pink asparagus. Therefore, it is preferable to turn the black and white plastic film over at different temperature stages.

[0085] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for creating pink asparagus, characterized in that: Includes the following steps: Step 1, Variety Selection: Select purple asparagus varieties that have stable anthocyanin synthesis and strong heat resistance; Step 2, Cultivation and Management: After clearing the garden, dig ditches and apply 1000±50 kg / mu of well-rotted organic fertilizer. The ditches should be 20-30 cm deep and 30-40 cm wide. Step 3, Mulching Management: First, set up a regular greenhouse, build a small arched shed inside the greenhouse, and cover it with black and white double-sided mulch film. In the initial state, if the ambient temperature is ≤15℃, the black film side should be facing up and the white film side should be facing down. The edges of the film should be pressed firmly, and the drip irrigation tape should be placed between the ditches. Step 4, Light and Temperature Control: After the temperature inside the greenhouse has been maintained within the range of 15℃-28℃ for a period of time, turn the black and white plastic film over so that the white film is facing up and the black film is facing down. When the temperature inside the greenhouse exceeds 28℃, open the greenhouse side window ventilation system to ensure that the temperature inside the small arched shed does not exceed 33℃. Step 5, Harvesting Management: When the asparagus enters the harvesting period, evenly distribute 90-125 micro-holes per square meter on the black and white double-color mulch film, with a hole diameter of 1-2mm. Every morning or evening, uncover the black and white double-color mulch film to harvest the pink asparagus. After harvesting, restore the black and white double-color mulch film in time. Step Six: Mother Stem Retention: After harvesting, remove the film to allow the plant to enter the vegetative growth period.

2. The method for creating pink asparagus according to claim 1, characterized in that: In step four, the temperature and light inside the small arched greenhouse are controlled by turning over the black-backed double-color mulch film and ventilating and cooling the greenhouse. This inhibits the activity of anthocyanin-degrading enzyme (PPO) in the asparagus inside the small arched greenhouse to ≤15U / gFW, thereby maintaining the anthocyanin concentration in the range of 0.2-0.5mg / gFW and preserving the "pink" expression of the asparagus.

3. The method for creating pink asparagus according to claim 1, characterized in that: The purple asparagus variety used in step one is Purple Passion.

4. The method for creating pink asparagus according to claim 1, characterized in that: In step three, the thickness of the black and white mulch film is 8-14 mils.

5. The method for creating pink asparagus according to claim 1, characterized in that: In step three, if the ambient temperature is below -2℃, a covering must be added to the small arched shed inside the greenhouse to prevent freezing and keep it warm, so as to ensure that the temperature inside the small arched shed is not lower than 5℃.

6. The method for creating pink asparagus according to claim 1, characterized in that: In step two, the composted organic fertilizer is a mixture of cow and sheep manure and soybean meal in a 7:3 ratio, with a C / N ratio of 25-30 and a pH of 6.8-7.

2.

7. The method for creating pink asparagus according to claim 1, characterized in that: In step five, the harvesting period is more than 60 days, and the harvesting period is gradually extended according to the age of the bamboo shoots. During this period, the temperature inside the black and white plastic film should not exceed 33°C and the air humidity should not exceed 65%.

8. The method for creating pink asparagus according to claim 1, characterized in that: In step three, hot-dip galvanized thin-walled steel pipes are used as the frame material. The width of a single steel frame arched shed is 6-8m and the length does not exceed 60m. The number of connected steel frame sheds does not exceed 10. The strength of the frame meets the local requirements for wind and snow resistance of agricultural greenhouses. The top of the greenhouse frame is covered with a multi-functional greenhouse film with a thickness of 0.06mm-0.08mm and a film width of 2.0m-3.0m plus the width of the greenhouse. The skirt film is 0.06mm-0.08mm thick.

9. The method for creating pink asparagus according to claim 1, characterized in that: In step three, the small arched shed is a rectangular arched shed with a height of more than 50cm from the ridge surface.

10. The method for creating pink asparagus according to claim 1, characterized in that: In step three, when the temperature inside the small greenhouse remains ≤15℃, the activity of anthocyanin synthase in the asparagus inside the small greenhouse is maintained at ≥45U / gFW by keeping the black film facing upward to enhance heat absorption.

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