Method for creating pink asparagus

Abstract

The invention discloses a pink asparagus creation method, and relates to the technical field of asparagus planting, the pink asparagus creation method comprises the following steps: 1, variety selection: selecting a purple asparagus variety with stable anthocyanin synthesis and strong heat resistance; step 2, cultivation management; a conventional greenhouse and a small rectangular arched shed are arranged and covered with a black and white mulching film with the light transmittance being 0 and the thickness being 8-12 threads, in the initial state, the black film face is upward, the white film face is downward, the film edge is compacted, and drip irrigation belts are arranged between ditches; 4, light and temperature regulation and control: when the day and night temperature in the greenhouse is continuously 15-28 DEG C, the black and white mulching film is turned over to enable the white film to face upwards and the black film to face downwards; step 5, harvesting management; and step 6, keeping the mother stems for breeding. According to the method, illumination and temperature control is decoupled through the external greenhouse and the internal small arched shed, and film surface overturning and micropore design are combined, so that regulation and control of illumination and temperature of the asparagus in the small arched shed are achieved, and pink expression of the purple asparagus in the small arched shed is kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of asparagus cultivation, in particular to a method for creating pink asparagus. BACKGROUND

[0002] Asparagus is one of the world's top ten famous dishes, rich in anthocyanins, selenium and other active ingredients. The current commercial varieties are mainly green asparagus and purple asparagus, among which purple asparagus is purple due to high anthocyanin content. In recent years, the market demand for rare color asparagus (such as pink) has increased, but the cultivation of pink asparagus has the following technical bottlenecks: Light and temperature coupling out of control: traditional single-layer greenhouse cannot separate light and temperature control. Although transparent film (transmittance > 80%) can control temperature, it induces chlorophyll synthesis, resulting in green asparagus; black film (heat absorption rate > 95%) can block light but make the temperature in the greenhouse exceed 35℃, activate anthocyanin degradation enzyme, and cause purple fading.

[0003] Poor variety adaptability: ordinary purple asparagus anthocyanin synthesis is unstable, and the activity of anthocyanin degradation enzyme increases at high temperature (> 30℃), resulting in fading.

[0004] Large operation disturbance: uncovering the film during the harvesting period causes sudden changes in temperature and humidity, and the anthocyanin concentration fluctuates by more than 40%.

[0005] The above defects lead to the failure of pink asparagus industrialization, and there is no stable production scheme in the industry. Therefore, a method is needed to decouple light and temperature control and achieve stable expression of pink. The present application plants asparagus in a double-layer greenhouse, precisely controls the light and temperature environment of purple asparagus, and finally plants unique pink asparagus. Pink asparagus has the sweetness advantage of purple asparagus and the fresh and crisp taste of white asparagus. Its sturdy and uniform shape and sweet and delicious taste are unique in the asparagus category. At the same time, pink asparagus not only enriches the product category in the agricultural market, but also has a better appearance. SUMMARY

[0006] One of the purposes of the present application is to provide a method for creating pink asparagus by dynamically controlling anthocyanin metabolism through light and temperature decoupling. The double-layer greenhouse structure decouples light and temperature control, combined with the film surface turnover mechanism and the micro-porous air flow system, to maintain the anthocyanin concentration in the range of 0.2-0.5 mg / g FW, thereby stably expressing the pink trait with the sweetness of purple asparagus and the fresh and crisp of white asparagus, breaking through the technical bottleneck of traditional planting, and realizing the mass production of pink asparagus.

[0007] To achieve the above purpose, the present application provides the following technical scheme: a method for creating pink asparagus, comprising the following steps: Step one, variety selection: choose the purple asparagus variety with stable anthocyanin synthesis and strong heat resistance. There are two types of asparagus, green and purple. Green asparagus cannot be cultivated into pink, but purple asparagus can. However, purple asparagus varieties are extremely rare and have different performance. Some purple varieties are not heat-resistant and have unstable purple expression, which directly affects the pink expression when cultivating pink asparagus from purple asparagus. Therefore, we need to choose purple asparagus that is heat-resistant and has stable purple expression. The preferred purple asparagus variety is Purple Passion, which has higher anthocyanin synthesis gene expression than ordinary purple asparagus and higher heat threshold than ordinary purple asparagus, ensuring stable coloring even at high temperatures inside the mulch film, thereby directing the cultivation of pink expression (research has found that the total anthocyanin content of different purple asparagus varieties differs by 2-3 times (such as Purple Passion, which usually contains >200 mg / kg, and ordinary varieties, which contain about 50-100 mg / kg).

[0008] Step two, cultivation management: after cleaning the garden, dig a ditch and apply 1000±50 kg / acre of decomposed organic fertilizer. The ditch is 20-30 cm deep and 30-40 cm wide. Step three, mulch management: first, set up a conventional greenhouse and build a small arched shed inside the greenhouse. Cover the black and white double-color mulch film. In the initial state, if the environmental temperature is ≤15℃, the black film surface faces up and the white film surface faces down. The black film surface faces up to enhance heat absorption, which can increase the temperature inside the small arched shed by 5-8℃ (the actual measured temperature inside the shed can reach 20-25℃). The white mulch film surface faces down to reflect internal stray light and provide weak light to avoid physiological disorders caused by complete darkness. The anthocyanin synthase (ANS) has the best activity at 15-25℃, especially at 20℃, which reaches the peak value, thereby maintaining the activity of anthocyanin synthase ≥45 U / g FW, promoting anthocyanin synthesis, and increasing the anthocyanin concentration to 0.2-0.5 mg / g FW. The film edge is compacted, and the drip irrigation tape is placed in the ditch. If the drip irrigation tape is placed on the surface of the furrow when supplementing water and fertilizer, it will cause water to enter the film, increasing the humidity inside the film. Placing it in the ditch can supplement the field water and normally supplement the root nutrients. Among them, the small arched shed is a rectangular small arched shed more than 50 cm away from the surface of the furrow. The specifications of the black and white double-color mulch film are 0% light transmittance and 8-12 silk thickness. The black and white double-color film is chosen because the temperature is low at the beginning of planting (usually in early spring), and the light duration is short. The black film on the top and the white film on the bottom can absorb sunlight to increase the temperature and promote early germination. The internal white color can appropriately supplement the early spring light and help pink coloring. In the greenhouse, hot-dip galvanized thin-walled steel pipe is used as the frame material, the single steel frame arched shed is generally 8m or 6m in width and preferably less than 60m in length, and the number of connected steel frame sheds is not more than 10. The top of the frame is covered with a multifunctional greenhouse film with a thickness of 0.06mm-0.08mm, and the width of the film is the width of the shed plus 2.0m-3.0m. The skirt film has a thickness of 0.06mm-0.08mm.

[0009] Step four, light and temperature regulation: when planting, as the temperature rises, the temperature in the greenhouse and small arch shed increases synchronously. In at least one time span of day and night, the temperature in the greenhouse is always maintained within the temperature range of 15℃-28℃. Therefore, it is necessary to turn the mulch over to the white side to reflect sunlight and reduce the temperature inside the small arch shed by 3-5℃ to avoid high temperature causing the asparagus to turn yellow. The black side faces down to insulate the ground radiation heat and reduce heat accumulation.

[0010] This is because the activity of anthocyanin-degrading enzyme (PPO) increases dramatically at >25℃, leading to the decomposition of anthocyanin. Reducing the temperature can inhibit the activity of asparagus anthocyanin-degrading enzyme (PPO) in the small arch shed ≤15U / gFW, slow down the degradation of anthocyanin, and thus maintain the anthocyanin concentration within the range of 0.2-0.5mg / gFW, keep the expression of "pink" asparagus, and avoid high temperature causing the asparagus to turn yellow; When the temperature in the greenhouse exceeds 28℃, open the side window ventilation system of the greenhouse to keep the temperature in the small arch shed not exceeding 33℃. Because there is a temperature difference between the greenhouse and the small arch shed, generally 4℃-7℃, and because the small arch shed is easy to transmit light, in order to avoid the temperature inside the small arch shed being too high, it is necessary to ventilate and cool the inside of the greenhouse to reduce the temperature inside the small arch shed. Step five, harvesting management: when asparagus enters the harvesting period, 90-125 holes with a size of micro-pores are evenly distributed on each square meter of the black and white mulch, with a diameter of 1-2mm. This is because the temperature is generally high at this time, and by setting the micro-pores, on the one hand, it can avoid the temperature inside the small arch shed being too high, maintain the balance of O2 / CO2 in the shed, stabilize the humidity, and at the same time, maintain a micro-air flow without damaging the light-shielding environment, and strictly control the light transmittance below 5%. The black and white mulch is opened every morning or evening to harvest the pink asparagus, and then the black and white mulch is restored in time to avoid large fluctuations in the temperature inside the black and white mulch and to avoid the pink asparagus being over-illuminated. Step six, mother stem maintenance: after harvesting, the mulch is removed and the asparagus enters the vegetative growth period.

[0011] Preferably, in step three, the black side of the black and white mulch has a light absorption rate ≥95% and the white side has a reflectivity ≥80%.

[0012] Preferably, in step three, when the ambient temperature is lower than -2℃, a covering such as a straw mat or non-woven fabric is added to the small arched shed in the greenhouse to prevent frost and maintain the temperature in the small arched shed at not lower than 5℃.

[0013] Preferably, in step two, the matured organic fertilizer is a mixture of cattle and sheep manure and soybean meal in a ratio of 7:3, the C / N ratio is 25-30, and the pH is 6.8-7.2.

[0014] 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 shoots, and the temperature in the black and white double-color mulch is maintained at not more than 33℃ and the air humidity is maintained at not more than 65% during the period.

[0015] Compared with the prior art, the present application has the following advantages: (1) The present application adopts a double-layer design of an external greenhouse and an internal small arched shed, which completely decouples light and temperature control: the external greenhouse adjusts the macro environment through a side window ventilation system (response > 28℃ high temperature), and the internal small arched shed uses black and white double-color mulch with a light transmittance of 0 to isolate light, combined with a dynamic film turning technology (black side up to absorb heat and increase temperature in low temperature period, and white side up to reflect heat and reduce temperature in high temperature period), successfully compressing the temperature fluctuation range of the small arched shed from ±10℃ in traditional planting to ±3℃. This breakthrough design stabilizes the anthocyanin concentration in the ideal pink interval of 0.2-0.5mg / g FW, and fundamentally solves the fading problem caused by light and temperature coupling in single-layer shed structure.

[0016] (2) The present application establishes a temperature-triggered film surface turning mechanism: when the ambient temperature is ≤15℃, the black film surface is turned up to significantly increase the ground temperature by 3-5℃, activating the anthocyanin synthase; when the temperature rises to 15-28℃, the white film surface is turned up to reflect solar radiation, effectively inhibiting the degradation enzyme. This technology breaks the vicious cycle of positive feedback of light and heat in traditional planting, significantly improves the anthocyanin synthesis efficiency, and breaks through the pink retention rate in high temperature environment of 28-33℃, and expands the stable interval of enzyme activity.

[0017] (3) The present application uniformly opens 90-125 micro-holes with a diameter of 1-2mm per square meter in the harvesting period, which can not only form stable air flow, maintain O2 / CO2 balance in the shed, stabilize humidity, reduce fungal spore germination rate, and extend the harvesting period to more than 60 days, but also can always strictly control the light transmittance below 5%, which is lower than the anthocyanin synthesis light threshold, and significantly improve the commodity rate.

[0018] (4) The present application strictly limits the film uncovering operation to the morning / early evening period when the light intensity is <20klux, avoids photo-oxidative damage, cooperates with rapid recovery of the film surface within 30 minutes, combines with pre-set micro-holes, and suppresses the temperature and humidity fluctuation within ±5%, reduces the anthocyanin concentration fluctuation and the cracking rate of shoots, improves the proportion of high-quality shoots, and completely solves the quality deterioration problem caused by traditional harvesting operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention provides a schematic flow chart of the steps of a method for producing pink asparagus. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1: This embodiment of the present invention provides a method for producing pink asparagus, comprising the following steps: Step 1. Variety selection: Choose a purple asparagus variety with stable anthocyanin synthesis and strong heat resistance. Conventional asparagus comes in two varieties: green and purple. Green asparagus cannot be cultivated into pink, while purple asparagus can be cultivated into pink. However, purple asparagus varieties are extremely rare and have different traits. Some purple varieties are not resistant to high temperatures, and their purple expression is unstable. This directly affects the pink appearance when cultivating pink asparagus from purple asparagus. Therefore, we need to select purple asparagus that is resistant to high temperatures and has stable purple expression. The preferred purple asparagus variety is Purple Passion, which has higher anthocyanin synthesis gene expression than ordinary purple asparagus and a higher heat resistance threshold than ordinary purple asparagus. This ensures that the coloration remains stable when the temperature inside the multi-membrane covering is high, thereby directing the cultivation of pink expression.

[0022] Step 2: Cultivation and management: After clearing the garden, dig ditches and apply 1000kg / mu of decomposed organic fertilizer. The ditch should be 20cm deep and 30cm wide. The decomposed organic fertilizer in step 2 is a mixed fermentation product of cattle 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; Step 3: Film management: First, set up a conventional greenhouse, build a small arch shed inside the greenhouse, and cover it with black and white double-color film. In the initial state, if the ambient temperature is ≤15℃, the black film side is upward and the white film side is downward. The black film side is facing upward to enhance heat absorption, so that the temperature in the small arch shed is increased by 5-8℃ (the measured temperature in the shed can reach 20-25℃). The white film side is facing downward to reflect internal scattered light, providing weak light to avoid complete darkness and cause physiological disorders; Anthocyanin synthase (ANS) has the best activity at 15-25°C, especially at 20°C, where it reaches its peak, thus maintaining anthocyanin synthase activity ≥45 U / g FW, promoting anthocyanin synthesis, and increasing anthocyanin concentration to 0.2-0.5 mg / g FW. The film edge is compacted, and the drip irrigation belt is placed in the ditch. If the drip irrigation belt is placed on the ridge when supplementing water and fertilizer, it will cause water to enter the film, increasing the humidity inside the film. Placing it in the ditch can supplement the field moisture and normally supplement the root nutrients. In this embodiment, the black and white double-color film has a thickness of 8 silk, and a light transmittance of 3%. This black and white double-color film is selected because the temperature is low at the initial stage of planting (generally in early spring), and the light duration is short. The black film on the top can absorb sunlight to increase the temperature and promote early germination. The white film on the bottom can appropriately supplement the early spring light, and is helpful for pink coloring. In this embodiment, the black and white double-color film has a thickness of 8 silk, and a light transmittance of 3%. This black and white double-color film is selected because the temperature is low at the initial stage of planting (generally in early spring), and the light duration is short. The black film on the top can absorb sunlight to increase the temperature and promote early germination. The white film on the bottom can appropriately supplement the early spring light, and is helpful for pink coloring. If the ambient temperature is lower than -2℃, a covering such as a straw curtain or non-woven fabric should be added on the small arch shed in the greenhouse to prevent frost and keep warm, so as to ensure that the temperature in the small arch shed is not lower than 5℃. In this embodiment, the black and white double-color film has a thickness of 8 silk, and a light transmittance of 3%. This black and white double-color film is selected because the temperature is low at the initial stage of planting (generally in early spring), and the light duration is short. The black film on the top can absorb sunlight to increase the temperature and promote early germination. The white film on the bottom can appropriately supplement the early spring light, and is helpful for pink coloring. The top of the shed frame is covered with a multifunctional greenhouse film with a thickness of 0.07 mm. The width of the film is the width of the shed plus 2.0 m. The skirt film has a thickness of 0.06 mm. Step four, light and temperature regulation: when planting, the temperature in the greenhouse and the small arch shed rises synchronously. The temperature in the greenhouse is always maintained within the temperature range of 15℃-28℃ for at least one day and night. At this time, the film needs to be turned over with the white film facing up to reflect sunlight and reduce the temperature in the small arch shed by 3-5℃, so as to avoid high temperature causing the asparagus to turn yellow. The black film faces down to isolate the ground radiation heat and reduce heat accumulation.

[0023] At the same time, the activity of anthocyanin-degrading enzyme (PPO) increases dramatically at >25℃, leading to the decomposition of anthocyanin. Reducing the temperature can inhibit the activity of anthocyanin-degrading enzyme (PPO) in the small arch shed to ≤15U / gFW, slow down the decomposition of anthocyanin, and thus maintain the concentration of anthocyanin within the range of 0.2-0.5mg / gFW, keeping the asparagus “pink”.

[0024] When the temperature in the greenhouse exceeds 28℃, the side window ventilation system of the greenhouse is opened to ensure that the temperature in the small arch shed does not exceed 33℃. Because there is a temperature difference between the greenhouse and the small arch shed, generally 4℃-7℃, and because the small arch shed is easy to ventilate and light, in order to avoid the temperature in the small arch shed being too high, the interior of the greenhouse needs to be ventilated to reduce the temperature, thereby reducing the temperature in the small arch shed. Step five, harvesting management: when asparagus enters the harvesting period, 100 holes with a size of micropore are evenly distributed on the black and white film per square meter, and the diameter of the micropore is 1-2 mm. This is because as the external temperature rises, by setting the micropore, on the one hand, it can avoid the temperature being too high inside the small arched shed, maintain the balance of O2 / CO2 in the shed, and stabilize the humidity, and at the same time, it can also maintain the micro air flow without destroying the light-shielding environment, and strictly control the light transmittance below 5%. The harvesting of pink asparagus should be carried out in the early morning or evening by uncovering the black and white film, and the black and white film should be restored in time after harvesting, so as to avoid large fluctuations in the temperature inside the black and white film and to avoid the pink asparagus being exposed to excessive light.

[0025] At the same time, because the plastic film has poor air permeability and the humidity in the shed is high, there is no water vapor accumulation on the white film upward in the morning, and there is water vapor accumulation on the black film upward in the morning. Therefore, the turning operation of the black and white film is also beneficial to the picking of pink asparagus.

[0026] Among them, the harvesting period is more than 60 days, and the harvesting period is gradually extended according to the age of the asparagus, and the temperature inside the black and white film should not exceed 33℃ and the air humidity should not exceed 65% during this period; Step six, mother stem maintenance: after harvesting, the film is uncovered and enters the vegetative growth period.

[0027] Example 2: The difference between this example and example 1 is only that the thickness of the black and white film used is different. In this example, a black and white film with a thickness of 12 silk is used.

[0028] Example 3: The difference between this example and example 1 is only that the thickness of the black and white film used is different. In this example, a black and white film with a thickness of 14 silk is used.

[0029] Comparative example 1: The difference between this comparative example and example 1 is that the thickness of the black and white film used is different. In this comparative example, a black and white film with a plurality of different thicknesses is used.

[0030] Table 1 is a table of film thickness and light transmittance of different control groups in examples 1-3 and comparative example 1

[0031] Table 2 is a color performance description of different groups in table 1

[0032] According to the above experimental results, it is found that the color change result is mainly affected by light and temperature: under light conditions, the synthesis of chlorophyll and anthocyanin in purple asparagus occurs, even if it is partial natural light, the synthesis of anthocyanin decreases under no light, the color gradually fades, and the color development weakens. Therefore, it is necessary to select a plastic film with a transmittance of less than 8 silk to induce the color change of purple asparagus into pink asparagus. The plastic film can not only block natural light, but also play a role in heat preservation. When the thickness reaches 16 silk, the temperature in the small shed is easy to be too high, which inhibits the synthesis of pigments and accelerates the degradation, resulting in yellowing and lightening of the pink color to yellow or white. Although the black and white double-color film with a thickness of 14 silk can meet the use requirements, considering that the thicker the plastic film, the higher the cost, therefore, the use of 8-12 silk is recommended.

[0033] Comparative Example 2: In this comparative example, the only difference from Example 1 is that a green and white double-color mulching film is used, with a thickness of 12 silk, and the mulching method is the same as Example 1, with the green side facing up in the early stage and the white side facing up in the later stage.

[0034] Comparative Example 3: In this comparative example, the only difference from Comparative Example 2 is that the mulching method of the green and white double-color mulching film is different, with the white side always facing up.

[0035] Comparative Example 4: In this comparative example, the difference from Comparative Example 2 is that the mulching method of the green and white double-color mulching film is different, with the green side always facing up.

[0036] Comparative Example 5: In this comparative example, the only difference from Example 1 is that a transparent film with a thickness of 12 silk (commonly used) is used.

[0037] Table 3 shows the differences in film color, light transmittance, and mulching method between Example 1 and Comparative Examples 2-5.

[0038] Table 4 shows the experimental results of color performance and average yield per mu for the corresponding groups in Table 1.

[0039] From the above experimental results, it is found that the green film in the green and white double-color film reduces the synthesis of chlorophyll, the purple asparagus head and scale color become pink, and the synthesis of anthocyanin is not significantly inhibited, so the purple asparagus only becomes lighter, not 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 early stage of the shed, therefore, the black and white double-color mulching film is preferred, and during planting, the turning operation of the black side facing up in the early stage and the white side facing up in the later stage should be followed.

[0040] Comparative Example 6: In this comparative example, the only difference from Example 1 is that the small hole density is different in step five.

[0041] Table 5 shows the control group settings with different micro-hole densities for Example 1.

[0042] Table 6 shows the test results of each group corresponding to Table 5

[0043] Data Analysis: The experimental results in Table 6 above show that only Control 1 and Example 1 have a yield per mu exceeding 3.00 kg / d. However, as the micropore density / diameter increases, light transmittance and air permeability increase, but thermal insulation decreases. The yield-increasing effect is poor in the early stage, but the color is stable in the later stage, the disease incidence is low, and the commercial value is good. However, when too much light transmittance is excessive, especially when the holes have large diameters, the asparagus color becomes light purple instead of pink.

[0044] Considering the two important indicators of pink asparagus ratio and commercial quality, the best is to have 100 uniform micropores per square meter (pore size is about 1-2mm) on the black and white double membrane.

[0045] Comparative Example 7: The difference between this comparative example and the above-mentioned Example 1 lies in the different laminating methods. In this comparative example, the white side is always facing upward.

[0046] Comparative Example 8: The difference between this comparative example and the above-mentioned Example 1 lies in the different laminating methods. In this comparative example, the black side is always facing upward.

[0047] Table 7 shows the difference between the coating methods of Example 1 and Comparative Examples 7 and 8.

[0048] Table 8 shows the experimental results of the coating methods for different groups in Table 7

[0049] From the above experimental results, it can be seen that: in the early stage of asparagus germination, the black plastic film has the effect of shading and keeping warm, and asparagus germinates in large quantities. If the white film faces upward, the temperature in the arch shed will rise too slowly, resulting in low yield. When the temperature rises in the later stage, the black film absorbs light and the highest temperature in the shed can reach 40°C, which affects the production of pink asparagus. Therefore, it is preferred to flip the black and white double-color film at different temperature stages.

[0050] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method of creating a pink asparagus, characterized by: The method comprises the following steps: Step one, variety selection: select a purple asparagus variety with stable anthocyanin synthesis and strong heat resistance; Step two, cultivation management: after cleaning the garden, dig a ditch and apply 1000±50 kg / mu of decomposed organic fertilizer with a depth of 20-30 cm and a width of 30-40 cm; Step three, film management: first set up a conventional greenhouse, build a small arch shed in the greenhouse, cover black and white double-color mulch, and place the drip irrigation belt in the ditch when the initial state is ≤15℃, the black film face up, the white film face down, and the film edge is compacted; Step four, light and temperature regulation: when the temperature in the greenhouse remains within the range of 15-28℃ for a period of time, the black and white double-color mulch is turned over with the white film facing up and the black film facing down; When the temperature in the greenhouse exceeds 28℃, open the side window ventilation system of the greenhouse to keep the temperature in the small arch shed not exceeding 33℃; Step five, harvesting management: when the asparagus enters the harvesting period, evenly distribute 90-125 micro-holes with a diameter of 1-2 mm per square meter on the black and white double-color mulch, and harvest the pink asparagus in the morning or evening, and then restore the black and white double-color mulch; Step six, mother stem maintenance: after harvesting, remove the film and enter the vegetative growth period.

2. A method of creating a pink asparagus according to claim 1, characterized in that: In step four, by turning over the black and white double-color mulch and ventilating and cooling the greenhouse, the temperature and light in the small arch shed are controlled, the activity of asparagus PPO (polyphenol oxidase) is inhibited ≤15 U / g FW, and the anthocyanin concentration is maintained within the range of 0.2-0.5 mg / g FW, so as to maintain the expression of "pink" asparagus.

3. The method for producing pink asparagus according to claim 1, wherein: The purple asparagus variety used in step one is "purple passion".

4. The method for producing pink asparagus according to claim 1, wherein: In step three, the thickness of the black and white double-color mulch is 8-14 silk.

5. A method of creating a pink asparagus according to claim 1, characterized in that: In step three, if the environmental temperature is lower than -2℃, a cover should be added to the small arch shed in the greenhouse to prevent frost and keep the temperature in the small arch shed not lower than 5℃.

6. The method of claim 1, wherein the pale colored asparagus is a pale green asparagus. 5 In step two, the decomposed organic fertilizer is a mixture of cow and sheep manure and soybean meal with a C / N ratio of 25-30 and a pH of 6.8-7.

2.

7. The method for producing pink asparagus according to claim 1, wherein: In step five, the harvesting period is more than 60 days, and the harvesting period is gradually extended according to the age of the asparagus, and the temperature in the black and white double-color mulch should not exceed 33℃ and the air humidity should not exceed 65% during this period.

8. The method for producing pink asparagus according to claim 1, wherein: In step three, hot-dip galvanized thin-walled steel pipes are used as the shed frame material, the shed width of the single steel arch shed is 6-8 m, the shed length is not more than 60 m, the number of connected steel arch sheds is not more than 10, and the shed frame strength meets the local agricultural greenhouse wind and snow resistance requirements; The top of the shed frame is covered with a multifunctional greenhouse film with a thickness of 0.06-0.08 mm, and the film width is the shed width plus 2.0-3.0 m, and the skirt film thickness is 0.06-0.08 mm.

9. The method for producing pink asparagus according to claim 1, wherein: In step three, the height of the small arch shed is a rectangular small arch shed with a height of more than 50 cm from the bed surface.

10. The method for producing pink asparagus according to claim 1, characterized in that: In step three, when the temperature in the small arch shed is continuously ≤15℃, the black film face up is maintained to enhance heat absorption and maintain the anthocyanin synthase activity in the asparagus in the small arch shed ≥45 U / g FW.

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