A sweet cherry off-season delayed cultivation method suitable for southern regions

Abstract

This invention relates to the field of sweet cherry cultivation technology in southern regions, specifically to a method for off-season delayed cultivation of sweet cherries suitable for southern regions. The method involves selecting heat-resistant sweet cherry varieties, using off-season greenhouses, and employing an intelligent environmental control system to regulate temperature and humidity, ensuring optimal conditions at different growth stages. During dormancy, the temperature is controlled at 2-4℃ through refrigeration and shading; during bud break, the temperature is raised to 10-20℃; during flowering, a suitable temperature of 12-25℃ is maintained; during the young fruit stage, supplemental lighting is combined with natural light; and during ripening, the temperature is controlled at 18-28℃. This method delays the ripening period of sweet cherries to July and August, and improves cultivation efficiency and fruit quality through remote monitoring and intelligent management, meeting the market demand for off-season fruits.

Description

Technical Field

[0001] This invention relates to the field of sweet cherry cultivation technology in southern regions, and more specifically, to a method for off-season delayed cultivation of sweet cherries in southern regions. Background Technology

[0002] Sweet cherry (Prunus avium L.), also known as big cherry or sweet cherry, is a deciduous fruit tree belonging to the genus Prunus, subgenus Prunus, family Rosaceae. Domestic sweet cherry cultivation is mainly concentrated in northern China, with the ripening period concentrated from March to June; domestic sweet cherries are rarely available in the market during other months. In southern regions, due to the warm and humid climate, especially the hot and rainy summers, sweet cherry cultivation, as one of the fastest-growing fruit trees in recent years, faces numerous challenges that urgently need to be addressed. Chinese invention patent applications (publication numbers: CN104885841A, CN104920134A, CN104838935A) and the applicant's Chinese invention patent application (publication number: CN107182683A, publication date: 2017-09-22) disclose cultivation methods for sweet cherries in warm southern regions, realizing the cultivation of sweet cherries in southern areas.

[0003] The cultivation area of ​​sweet cherries is gradually expanding in southern regions such as Zhejiang. Production is mostly carried out using rain-sheltered and shaded methods, with the fruit typically ripening in May. However, through early cultivation, the fruit ripening period can be advanced to April. For example, the applicant's Chinese invention patent application (Publication No.: CN114931058A, Publication Date: 2022-08-23) discloses a cultivation method for promoting early ripening of sweet cherries in southern regions through temperature and humidity control. This method utilizes a greenhouse covering and heating technology to promote bud and flower development. Under conditions where the chilling requirements meet the cherry's dormancy needs, reasonable temperature control during the budding and fruit coloring stages induces earlier budding and ripening, altering the growth cycle and allowing the fruit to be marketed earlier. The same sweet cherry variety can ripen in mid-to-late March, 30-40 days earlier than with ordinary rain-sheltered and shaded cultivation, significantly improving economic benefits.

[0004] Currently, off-season cultivation of sweet cherries mainly focuses on "raising temperatures to promote early growth," while research on "lowering temperatures to delay growth" is limited. In southern regions like Zhejiang, there are currently no sweet cherries ripening in July and August. Off-season delayed cultivation of sweet cherries in southern regions faces numerous challenges, with the summer heat being particularly prominent. This not only limits off-season cultivation but also negatively impacts rain-sheltered, shaded cultivation. In July 2024, the average temperature in Taizhou, Zhejiang, was 29.85℃, with a maximum of 38.90℃ and a minimum of 25.70℃. The high external temperatures severely restrict off-season sweet cherry cultivation. Therefore, "external shading and internal supplemental lighting" is one effective way to address the high-temperature problem during fruit ripening in southern regions. With the continuous improvement of sweet cherry cultivation techniques, off-season delayed cultivation is gradually gaining attention, but issues such as environmental condition control for off-season sweet cherry cultivation need further resolution. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a method for off-season delayed cultivation of sweet cherries suitable for southern regions. This method utilizes scientific environmental control equipment and supplemental lighting technology to ensure efficient growth of sweet cherries in off-season environments and improve fruit quality to meet market demands.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for off-season delayed cultivation of sweet cherries suitable for southern regions, the method comprising the following steps:

[0008] 1) Select heat-resistant sweet cherry varieties suitable for planting in southern regions;

[0009] 2) Off-season cultivation greenhouses are covered with light-blocking rubber and plastic insulation cotton on the outside, and the temperature and humidity inside the greenhouses are regulated by intelligent artificial environment control units.

[0010] 3) During the dormancy period from April to May, the greenhouse is kept dormant by cooling and maintaining a temperature of 2-4℃ inside, with no light.

[0011] 4) During the budding period in May, gradually increase the temperature, turn on the insulation cotton, and control the temperature inside the greenhouse to 10-20℃;

[0012] 5) During the flowering period from May to June, simulate normal spring temperatures and control the temperature inside the greenhouse at 12-25℃;

[0013] 6) During the young fruit stage from mid-June to early July, control the temperature inside the greenhouse at 15-25℃ and use supplemental lighting and natural light for photosynthesis. The supplemental lighting used is Zhongke Xicai supplemental lighting with a red-to-blue light ratio of 1.8. High-density supplemental lighting of 1m × 0.75m is used, with the supplemental lights 20cm to 80cm away from the leaves. During this period, the temperature in the off-season greenhouse is controlled between 20℃ and 25℃. The duration of light exposure is controlled at 15-18 hours per day, and the supplemental lights automatically turn on when the natural light level drops below 930 Lux.

[0014] 7) During the ripening period from July to August, control the temperature inside the greenhouse to 18-28℃;

[0015] 8) After harvesting in September-October, the refrigeration unit does not need to be turned on, the insulation cotton is opened, the greenhouse film is fully opened, and normal management is carried out, while strengthening fertilizer and water management.

[0016] As preferred varieties, heat-resistant sweet cherry varieties are "Qizao" or "Meizao".

[0017] As preferred options, "Qizao" is a 5-year-old KGB tree with a slender spindle shape, while "Meizao" is a 4-year-old slender spindle tree with a slender spindle shape.

[0018] As preferred options, during the young fruit stage, the temperature inside the greenhouse for "Qizao" off-season cultivation is controlled at 20℃, and the temperature inside the greenhouse for "Meizao" off-season cultivation is controlled at 25℃.

[0019] As a preferred option, the off-season cultivation greenhouse is a single arched greenhouse, 40m long and 11m wide, with a 5cm thick rubber and plastic insulation cotton covering the outside.

[0020] As a preferred option, the Zhongke Rare Talent supplementary light has a power of 60W, a main wavelength of 699.0nm, a luminous flux of 4030.42 1m, and is used for supplementary lighting from 6:00 to 22:00 daily.

[0021] Preferably, the supplemental lights are installed at a height of 40cm to 120cm, and are arranged at different heights according to the different tree shapes to ensure the uniformity of photosynthesis in sweet cherries.

[0022] As a preferred option, fertilization management includes applying urea, potassium dihydrogen phosphate, and micronutrient fertilizers to supplement nutrients in stages, ensuring improved photosynthetic efficiency of leaves and enhanced fruit quality.

[0023] As a preferred option, the temperature, humidity, and light intensity inside the greenhouse are monitored in real time using a remote monitoring device to ensure that the growing environment for sweet cherries is always in the best condition.

[0024] As a preferred method, mature fruits can be obtained in July and August through off-season cultivation.

[0025] This invention, by employing the aforementioned technical solution, provides a method for off-season delayed cultivation of sweet cherries suitable for southern regions. Targeting the hot and humid climate of southern China, it achieves efficient off-season production of sweet cherries through multi-step temperature, humidity, and light control, delaying fruit ripening to July and August. This method has the following significant technical effects:

[0026] 1. High-efficiency environmental control: An intelligent artificial environmental control system, combined with shading rubber and plastic insulation, ensures precise control of temperature and humidity within the greenhouse. Especially during dormancy and budding, precise temperature regulation maintains a low temperature of 2°C to 4°C and a dark environment, successfully inducing sweet cherries to enter dormancy and effectively breaking dormancy. This control avoids the adverse effects of high temperatures in the south on dormancy and budding, ensuring that sweet cherries grow and develop within a suitable temperature range.

[0027] 2. Optimized Effect of Combining Supplemental Light and Natural Light: From the young fruit stage to the fruit ripening stage, the use of Zhongke Xicai supplemental lighting (red-blue light ratio 1.8) combined with natural light achieved optimized supplementation of light within the greenhouse. This supplemental lighting technology provided 15 to 18 hours of light daily from June to July, ensuring stable photosynthesis in sweet cherries, increasing the net photosynthetic rate, and significantly promoting fruit development and quality improvement. Through the rational arrangement of high-density supplemental lighting (1m × 0.75m), light evenly covered the tree canopy, avoiding insufficient or excessively concentrated light.

[0028] 3. Improved Fruit Quality and Yield: This invention maintains a suitable temperature of 20℃ to 25℃ during the young fruit and ripening stages, ensuring that sweet cherries undergo fruit enlargement and sugar accumulation at the optimal temperature. Experiments show that this method effectively increases the soluble solids content of the fruit, increases the weight of individual fruits, and significantly improves the appearance and taste of the fruit, thereby enhancing its commercial value.

[0029] 4. Extended Harvest Period and Enhanced Market Value: Through precise temperature, humidity, and light management, this invention extends the ripening period of sweet cherries to July and August, breaking traditional seasonal limitations, extending the supply cycle of sweet cherries, and filling the market gap in summer sweet cherry supply. This delayed cultivation method provides growers in southern regions with broader market prospects and economic benefits.

[0030] 5. Intelligent Monitoring and Energy Saving: By remotely monitoring and controlling temperature, humidity, and light intensity in real time, this invention achieves intelligent management of the sweet cherry cultivation process, reducing manual intervention and significantly improving cultivation efficiency. Simultaneously, during non-critical growth periods, such as September and October, opening the greenhouse film and insulation cotton allows for natural cooling and ventilation management, reducing energy consumption and achieving energy conservation and environmental protection.

[0031] In summary, this invention significantly improves the growth efficiency, fruit quality, and economic benefits of sweet cherries in off-season delayed cultivation in southern regions through a number of innovative temperature, humidity, and light control technologies, and has broad application prospects. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0033] Example 1: Off-season delayed cultivation method for sweet cherries in southern regions

[0034] 1. Variety selection

[0035] In this embodiment, the sweet cherry varieties "Qizao" and "Meizao" were selected, both suitable for the high-temperature climate conditions of southern regions. "Qizao" is suitable for 5-year-old KGB tree training, while "Meizao" is suitable for 4-year-old slender spindle tree training. Both varieties have strong tolerance to high-temperature environments and can adapt to the off-season cultivation needs of southern regions.

[0036] 2. Greenhouse structure and environmental control

[0037] The off-season cultivation greenhouse adopts a single-span arched structure, 40 meters long and 11 meters wide, covered with 5 cm thick rubber and plastic insulation cotton to ensure the stability of temperature control inside the greenhouse. The greenhouse uses an intelligent artificial environment control unit to create a suitable environment for sweet cherry growth through precise control of temperature and humidity, especially ensuring the off-season temperature requirements.

[0038] 3. Dormant period management (April-May)

[0039] During the dormancy period from April to May, refrigeration equipment is used to control the temperature inside the greenhouse at 2°C to 4°C, and the greenhouse is kept in a dark environment to simulate natural winter dormancy conditions. This low temperature and dark environment effectively breaks the dormancy period of sweet cherries and avoids the adverse effects of high temperatures on sweet cherry dormancy.

[0040] 4. Management during the budding stage (May)

[0041] After the budding period begins in May, the temperature inside the greenhouse is gradually increased, the insulation cotton is opened, and the temperature is controlled between 10℃ and 20℃ to simulate the temperature change process under natural conditions, so as to promote the sweet cherry to bud successfully and begin to grow and develop.

[0042] 5. Flowering period management (May-June)

[0043] During the flowering period from May to June, the temperature inside the greenhouse is controlled between 12℃ and 25℃ to simulate spring temperatures, ensuring normal flower opening and pollination. At this time, the greenhouse temperature needs to be dynamically adjusted to cope with external climate changes and ensure the successful completion of the flowering period.

[0044] 6. Management during the young fruit stage (mid-June to early July)

[0045] During the young fruit stage from mid-June to early July, the temperature inside the greenhouse is controlled at 20℃ to 25℃. Temperature adjustments are made according to the variety; for example, the temperature for the "Qizao" variety is maintained at 20℃, and for the "Meizao" variety at 25℃. Supplemental lighting is particularly important during this stage. Zhongke Xicai supplemental lighting lamps with a red-to-blue light ratio of 1.8 are used, installed at a distance of 20cm to 80cm, in conjunction with natural light for photosynthesis. Supplemental lighting lasts for 15 to 18 hours daily. When the external light intensity drops below 930 Lux, the supplemental lighting automatically turns on to ensure sufficient light to promote healthy fruit growth.

[0046] 7. Maturity Stage Management (July-August)

[0047] During the fruit ripening period from July to August, the temperature inside the greenhouse is controlled between 18℃ and 28℃ to ensure that the fruit ripens at the optimal temperature. At the same time, supplemental lighting is continued to ensure that the fruit accumulates sufficient sugar during photosynthesis, thereby improving the quality and taste of the fruit.

[0048] 8. Post-harvest management (September-October)

[0049] From September to October, after the fruit harvest, refrigeration equipment is no longer needed. At this time, the insulation is removed, the greenhouse film is completely uncovered, and normal natural management is carried out. During this stage, fertilizer and water management is strengthened to prepare for the cultivation of the next season of sweet cherries.

[0050] 9. Supplemental lighting configuration and fertilization management

[0051] The installation height of supplemental lighting is rationally arranged according to the tree shape, ranging from 40cm to 120cm, to ensure uniform light coverage of the entire canopy. For fertilization, urea, potassium dihydrogen phosphate, and trace element fertilizers are used, with nutrients supplemented in stages. Topdressing is applied before flowering, during the young fruit stage, and during fruit ripening to ensure improved leaf photosynthetic efficiency and fruit quality.

[0052] 10. Remote monitoring and automated management

[0053] The temperature, humidity, and light intensity inside the greenhouse are monitored in real time via remote monitoring devices. The intelligent system automatically adjusts these parameters based on environmental data to ensure the sweet cherry growing environment is always optimal. This system also significantly reduces the complexity of manual operations and improves management efficiency.

[0054] Through the above implementation plan, the off-season delayed cultivation of sweet cherries has achieved remarkable results in southern regions. Experimental results show that, using the cultivation method of this invention, sweet cherry fruits can ripen smoothly in July and August, with significant improvements in single fruit weight, soluble solids content, and fruit firmness. Especially during the temperature and light control process from the young fruit stage to maturity, the fruit quality of sweet cherries remains stable, with a sweet taste and significantly enhanced market competitiveness.

[0055] Test case

[0056] To verify the effectiveness of the off-season delayed cultivation method for sweet cherries in southern regions in this invention, the applicant conducted the following experiment.

[0057] 1. Materials and Methods

[0058] 1.1 Test Materials

[0059] This study was conducted in an off-season greenhouse at the Taizhou Academy of Agricultural Sciences, where temperature and light were controlled by artificial intelligence. The sweet cherry varieties "Qizao" and "Meizao" were used as test materials. "Qizao" was a 5-year-old KGB-shaped tree, and "Meizao" was a 4-year-old slender spindle-shaped tree with consistent tree vigor and conventional management practices, referencing Chinese Invention Patent CN201710524755.5. The off-season greenhouse was a single-span arched greenhouse, 40m long and 11m wide, covered with 5cm thick rubber-plastic insulation. Temperature and humidity were regulated inside the greenhouse using two 10KW intelligent artificial environment control units for sweet cherries (Zhengjin Environmental Technology Co., Ltd.). Three different types of supplemental lighting were used: ordinary supplemental lighting, Zhongke Rare Talent supplemental lighting, and full-spectrum plant supplemental lighting. Both the intelligent artificial environment control units and the supplemental lighting could operate automatically by setting temperature and light thresholds.

[0060] Standard grow light: 60W, white light. Zhongke Rare Talent grow light: 60W, dominant wavelength: 699.0nm, luminous flux: 4030.421m, red-to-blue light ratio (R / B): 1.8. Full-spectrum plant grow light: 60W, dominant wavelength: 699.4nm, luminous flux: 3042.681m, red-to-blue light ratio (R / B): 2.5. During the photosynthesis period, the external rubber-plastic insulation cotton of the greenhouse was not turned on, and there was no natural light inside the greenhouse; only artificial light was provided by grow lights. Supplemental lighting time: From mid-June to early July, 1m×1.5m low-density grow lights or 1m×0.75m high-density grow lights were used. The grow lights were used from 6:00 to 22:00. During this period, when the external natural light was below 930 Lux, the grow lights were automatically activated. The insulation cotton is manually turned on at 7:00 AM and manually turned off at 5:00 PM, with a total effective light duration of 16 hours per day. A Pengyun S21A remote monitoring instrument is used to collect data on air temperature, soil temperature, and light intensity inside the greenhouse every 5 minutes.

[0061] 1.2 Test Methods

[0062] 1.2.1 Effect of different temperatures on the synthetic efficiency of supplemental lighting for sweet cherries

[0063] Four treatments, T1-T4 (with set temperature thresholds of 10℃, 15℃, 20℃, and 25℃ respectively), were set up. A LI-6400X portable photosynthesis system was used to measure the net photosynthetic rate (Pn), stomatal conductance (Cond), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of 'Qizao' and 'Meizao' varieties under different temperature conditions. Three plants were randomly selected from each treatment, and three mature leaves from the middle of the new shoots of each plant were selected from different directions for measurement. Photosynthesis was measured at a distance of 80cm from the light source (light intensity 2595.93 Lux). Supplemental lighting was installed at a density of 1m × 0.75m. Measurements for T1-T4 were taken around 9:20, 11:00, 13:00, and 14:00, respectively. During these times, the greenhouse insulation was not turned on, and the temperature rose naturally and slowly.

[0064] 1.2.2 Effects of different light qualities of supplemental lighting on photosynthesis in sweet cherries

[0065] Three treatments (M1-M3, representing ordinary supplemental lighting, Zhongke Rare Talent Supplemental Lighting, and full-spectrum plant supplemental lighting, respectively) were set up. Net photosynthetic rate (Pn), stomatal conductance (Cond), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of sweet cherry were measured using a LI-6400X portable photosynthesis system under variable light intensity conditions. Three plants were randomly selected from each treatment, and three mature leaves from the middle of the new shoots of each plant were selected from different directions for measurement. Photosynthesis was measured at a distance of 80 cm from the light source. During the photosynthesis measurement period, the rubber-plastic insulation cotton was not turned on, and there was no natural light inside the greenhouse; only artificial light from the supplemental lighting was provided. The ambient temperature inside the greenhouse was 20℃ during the measurement period. The supplemental lighting was installed at a density of 1m × 0.75m.

[0066] 1.2.3 Effects of different distances of supplemental lighting on photosynthesis in sweet cherries

[0067] Four treatments, N1-N4 (located at distances of 20cm, 40cm, 80cm, and 120cm from the light source, respectively), were set up. Using a LI-6400X portable photosynthesis system under variable light intensity conditions, parameters such as net photosynthetic rate (Pn), stomatal conductance (Cond), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of sweet cherry leaves at different distances from the supplemental lighting were measured at 20℃. The supplemental lighting was provided by Zhongke Xicai, installed at a density of 1m × 1.5m. Three plants were randomly selected from each treatment, and three mature leaves from the middle of three new shoots on each plant were selected for measurement from different directions. The measurements were repeated three times, and the average value was taken. During the photosynthesis measurement period, the rubber-plastic insulation cotton was not turned on, and there was no natural light inside the greenhouse; only artificial light from the supplemental lighting was provided. The ambient temperature inside the greenhouse during the measurement period was 20℃.

[0068] 1.2.4 Effects of different densities of supplemental lighting on photosynthesis in sweet cherries

[0069] Two treatments, S1 and S2, were set up, with supplemental lighting installed at densities of 1m×1.5m and 1m×0.75m, respectively. A LI-6400X portable photosynthesis system was used to measure parameters such as net photosynthetic rate (Pn), stomatal conductance (Cond), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of sweet cherries under variable light intensity conditions. The supplemental lighting was a Zhongke Xicai supplemental lighting lamp (60W), and the measurement temperature was 20℃. Three trees were randomly selected from each treatment, and three mature leaves from the middle of three new shoots on each tree were selected for measurement in different directions. The measurements were repeated three times, and the average value was taken. During the photosynthesis measurement period, the rubber-plastic insulation cotton was not turned on, and there was no natural light inside the greenhouse; only artificial light from the supplemental lighting was provided.

[0070] 1.2.5 Effects of different supplemental lighting treatments on the quality of sweet cherry fruit

[0071] Three different treatments were set up: P1-P3 ordinary supplemental lighting, Zhongke Rare Talent supplemental lighting, and full-spectrum supplemental lighting. 30-40 fully ripe sweet cherry fruits were randomly selected, and their individual fruit weight, soluble solids content, and other important indicators were measured. The weight of the fruits was randomly measured using a 0.1% electronic balance. Fruit firmness was measured directly with the peel using a GY-1 hardness tester. Total soluble solids, total acid, and sugar-acid ratio were measured using a Japanese Aite fruit sugar-acid analyzer. The fruit flavor and taste were evaluated according to the "Cherry Germplasm Resource Description Specification and Data Standards," and the sweetness and acidity of the fruit were visually assessed.

[0072] 1.3 Statistical Analysis

[0073] Data were statistically processed using Microsoft Office Excel 2007, and the variance analysis was performed using STST software to analyze the variance of the results of the one-way randomized block experiment.

[0074] 2. Results and Analysis

[0075] 2.1 Effect of different temperatures on the synthetic efficiency of supplemental lighting for sweet cherries

[0076] Table 1 shows that the air temperature inside the greenhouse was not significantly different from the set temperature thresholds for each treatment, indicating that the air temperature inside the greenhouse could be maintained at the required experimental temperature during the experiment. Research on the air temperature in the photosynthesis instrument sample chamber, leaf temperature, and calculated leaf temperature parameters revealed that under the 10℃ low-temperature treatment condition, the leaf temperatures of both "Qizao" and "Meizao" exceeded 15℃. As the temperature increased, the leaf temperatures of both "Qizao" and "Meizao" gradually increased, with the leaf temperature of "Meizao" being slightly higher than that of "Qizao." The same pattern was observed with both ordinary supplemental lighting and Zhongke Rare Talent supplemental lighting. In summary, the leaf temperature gradually increased with the increase of the external temperature and remained higher than the ambient temperature. When the external temperature was below 15℃, the leaf temperature did not decrease with the decrease of the ambient temperature to maintain normal tree growth.

[0077] Table 1 Effects of different temperature treatments on the leaf temperature of sweet cherry

[0078]

[0079]

[0080] Table 2 shows that temperature has a significant impact on the photosynthesis of sweet cherries. The net photosynthetic rate of 'Qizao' cultivar reaches its maximum at 20℃, while that of 'Meizao' cultivar reaches its maximum at 25℃. Both ordinary supplemental lighting and Zhongke Rare Earth supplemental lighting exhibit the same trend. With the continuous increase of leaf temperature from T2 to T4, the stomatal conductance and transpiration rate of both 'Qizao' and 'Meizao' cultivars gradually increase, reaching their maximum at 25℃. Both ordinary supplemental lighting and Zhongke Rare Earth supplemental lighting show the same trend. In conclusion, temperature has a significant impact on the photosynthesis of sweet cherries. Sweet cherry leaves require specific temperature conditions for photosynthesis; some leaves may not produce effective photosynthesis when the air temperature is below 15℃. The photosynthetic rate of 'Qizao' cultivar reaches its maximum at 20℃, while that of 'Meizao' cultivar reaches its maximum at 25℃.

[0081] Table 2 Effects of different temperature treatments on photosynthesis in sweet cherries

[0082]

[0083]

[0084] 2.2 Effects of different supplemental lighting treatments on photosynthesis of sweet cherries in greenhouses

[0085] Table 3 shows that there are certain differences in the light intensity measured by different supplemental lighting lamps. The Zhongke Xicai supplemental lighting lamp, measured using the Pengyun S21A remote monitoring instrument, had the highest intensity, while the full-spectrum supplemental lighting lamp had the weakest. The light intensity inside and outside the leaf chamber, measured using the LI-6400X portable photosynthesis meter, also showed the highest value for the Zhongke Xicai supplemental lighting lamp. Both "Qizao" and "Meizao" varieties showed the highest net photosynthetic rate and the lowest intercellular CO2 concentration under the Zhongke Xicai supplemental lighting lamp. Under the same power conditions, ordinary supplemental lighting produces white light, the Zhongke Xicai supplemental lighting lamp produces red-blue light, and the full-spectrum plant supplemental lighting lamp produces off-white light. In conclusion, different supplemental lighting lamps have a significant impact on the photosynthesis of sweet cherries, and the comprehensive evaluation indicates that the Zhongke Xicai supplemental lighting lamp has the best effect.

[0086] Table 3. Effects of different supplemental lighting on photosynthesis in sweet cherries.

[0087]

[0088] 2.3 Effects of different distances of supplemental lighting on photosynthesis of sweet cherries in greenhouse

[0089] Table 4 shows that different distances of supplemental lighting have a significant impact on the photosynthesis of sweet cherries. Among them, the 'Meizao' variety had the highest light intensity inside the leaf chamber at a distance of 15cm from the supplemental light source, reaching 423.66 μmol / m². -2 s -1At this distance, the net photosynthetic rate is the highest. At a distance of 120cm from the supplemental light, the light intensity is only 5.42% of that at 15cm, and the net photosynthetic rate gradually decreases with increasing distance. 'Qizao' exhibits the same pattern: at 20cm, the light intensity inside the leaf chamber is the highest, along with the highest net photosynthetic rate, stomatal conductance, and transpiration rate; at 120cm, the light intensity inside the leaf chamber is the weakest, the net photosynthetic rate is the lowest, and the intercellular CO2 concentration is the highest. In summary, different distances for supplemental lighting have a significant impact on the photosynthesis of sweet cherries. The closer to the supplemental light, the greater the light intensity, the higher the net photosynthetic rate, and the better the supplemental lighting effect. However, excessively close proximity can cause leaf burn due to the high temperature of the supplemental light. Therefore, a distance of 20cm-80cm from the leaves is ideal for the supplemental light.

[0090] Table 4. Effects of different supplemental lighting on the photosynthetic rate of sweet cherries

[0091]

[0092] 2.4 Effects of different densities of supplemental lighting on photosynthesis of sweet cherries in greenhouses

[0093] Table 5 shows that different densities of supplemental lighting significantly affect light intensity and photosynthesis in sweet cherries within the greenhouse. Under the same distance conditions, the light intensity of a 1m × 1.5m supplemental light is only about 50% of that of a 1m × 0.75m supplemental light. The net photosynthetic rate of "Qizao" and "Meizao" cherries is almost zero under low-density supplemental lighting. Increasing the supplemental lighting density significantly improves the net photosynthetic rate of sweet cherries. Under low-density supplemental lighting, the intercellular CO2 concentration and transpiration rate are relatively higher, and the leaf temperature is higher than under high-density conditions. In conclusion, supplemental lighting density affects the photosynthesis of sweet cherries. Increasing the supplemental lighting density can effectively enhance photosynthesis. For the KGB-shaped "Qizao" cherries, a 1m × 0.75m density supplemental lighting setup yields the best results.

[0094] Table 5. Effects of different supplemental lighting densities on the photosynthetic rate of sweet cherries.

[0095]

[0096]

[0097] 2.5 Effects of different supplemental lighting treatments on the quality of sweet cherries in greenhouses

[0098] Table 6 shows that different supplemental lighting treatments had a significant impact on the fruit quality of sweet cherries. The single fruit weight of both "Qizao" and "Meizao" varieties was highest under the Zhongke Rare Earth Supplemental Lighting treatment. Similarly, the soluble solids content was highest under the Rare Earth Supplemental Lighting treatment, with "Qizao" reaching 20.05%. Compared to the control treatment, the Rare Earth Supplemental Lighting treatment reduced the total acid content and increased the fruit's acid-to-solids ratio. In conclusion, the Zhongke Rare Earth Supplemental Lighting treatment had the best overall effect, resulting in fruit quality superior to the control and full-spectrum supplemental lighting treatments.

[0099] Table 6. Effects of different supplemental lighting on the quality of sweet cherries.

[0100]

[0101] 3. Conclusion

[0102] This invention, through research on the temperature of sweet cherry leaves under different temperature conditions, found that when leaves are in a low-temperature environment of 10℃, their temperature still remains above 15℃, and sweet cherries cannot grow normally in a long-term low-temperature environment. Sweet cherry leaves require specific temperature conditions for photosynthesis. The photosynthetic rate of both the "Qizao" and "Meizao" sweet cherry varieties was lower under the 10℃ low-temperature treatment than under other treatments. "Qizao" reached its maximum net photosynthetic rate at 20℃. Although leaf temperature, stomatal conductance, and transpiration rate all increased to varying degrees with further increases in temperature, its net photosynthetic rate actually decreased to some extent, possibly due to its intense respiration. Sweet cherry photosynthesis is affected by many factors such as temperature, light intensity, stomatal conductance, and CO2 concentration. "Meizao" reached its maximum net photosynthetic rate at 25℃, and its net photosynthetic rate increased continuously with increasing temperature from 10℃ to 25℃. Treatments T1-T4 were all performed under dark conditions using ordinary supplemental lighting and Zhongke Rare Talent supplemental lighting. The light intensity was relatively weaker than natural light. The study showed that a certain net photosynthetic rate existed under the 10℃ low-temperature treatment. Photosynthesis gradually increased with rising temperature; however, further increases in temperature would intensify respiration, leading to a continuous decrease in the net photosynthetic rate. This research can provide some reference for temperature control in off-season sweet cherry cultivation: "Qizao" cherries are more adaptable to low temperatures and weak light, and nighttime supplemental lighting for "Qizao" can maintain a temperature of 20℃; "Meizao" cherries are more suitable for medium to high temperature management, and nighttime supplemental lighting for "Meizao" can maintain a temperature of 25℃.

[0103] This invention, through research on three different types of supplemental lighting, found that the Zhongke Rare Talent Supplemental Light has the highest supplemental lighting efficiency among the three. At a distance of 80cm from the light source, its illuminance can reach 3060 Lux, at which point the net photosynthetic rate of "Qizao" can reach 4.46 μmol CO2 m. -2 s -1Compared to monochromatic red and blue light, an appropriate red-blue light ratio can effectively promote leaf development and improve photosynthetic capacity. In this experiment, the net photosynthetic rate of sweet cherries was highest when the red-to-blue light ratio (R / B) of the supplemental lighting lamp from Zhongke Xicai was 1.8. Due to the abundant rainfall and short daylight hours in southern regions during spring and summer, greenhouses often experience low light levels and high humidity. The application of supplemental lighting lamps can not only effectively supplement light but also reduce humidity to some extent, thus solving the problem of fruit cracking in sweet cherries in southern regions.

[0104] Studies have shown that light intensity decreases with increasing supplemental lighting height. Experiments also revealed that the distance between the supplemental lights significantly affects the light intensity and net photosynthetic rate of sweet cherries. For 'Qizao' cherries, the net photosynthetic rate is close to zero at a supplemental lighting distance of 100cm, while for 'Meizao' cherries, the net photosynthetic rate is negative at 100cm. Too close a distance can cause high-temperature scorching of sweet cherry leaves. Therefore, the supplemental lighting distance for off-season sweet cherries should be ≤100cm to achieve effective supplemental lighting. Generally, for melons and fruits, the distance between the supplemental lights and the leaves is 30cm-120cm, with a distance of 3m between lights. However, previous experiments have shown that a low supplemental lighting density (1m×1.5m) results in a lower net photosynthetic rate under different temperature and light quality conditions. Therefore, appropriately increasing the supplemental lighting density (1m×0.75m) is an effective way to promote photosynthesis in sweet cherries. After years of observation and experimentation, the KGB tree shape is one of the tree shapes suitable for cultivation in southern regions. In this experiment, the density of the supplementary lights is 1m×0.75m, which is more suitable. In the experiment, the light intensity at the upper and lower parts of the slender, spindle-shaped "Meizao" tree is relatively weak, so it is more suitable to use a staggered arrangement of supplementary lights.

[0105] This invention reveals that off-season sweet cherries exhibit significantly improved fruit quality, with the "Qizao" variety exceeding the soluble solids content of conventionally cultivated cherries. Different light qualities significantly impact fruit quality; in this invention, the Zhongke Xicai supplemental lighting with a red-to-blue light ratio (R / B) of 1.8 produces the best fruit quality, exhibiting high soluble solids content, low total acid content, and a rich flavor, significantly superior to ordinary supplemental lighting. Sweet cherry cultivation in southern regions faces numerous challenges, with summer heat being particularly prominent. This not only limits off-season cultivation but also negatively impacts rain-sheltered, shaded cultivation. "External shading and internal supplemental lighting" is an effective way to address the high-temperature challenge during fruit ripening in southern regions.

[0106] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for off-season delayed cultivation of sweet cherry suitable for southern regions, characterized in that, The method comprises the following steps: 1) selecting a high-temperature-resistant sweet cherry variety suitable for planting in the southern region and planting in the southern region; 2) cultivating a greenhouse in an off-season, covering the outside of the greenhouse with light-shielding rubber plastic insulation cotton, and using an intelligent artificial environment control unit to regulate the temperature and humidity in the off-season cultivation greenhouse; 3) during the dormancy period from April to May, refrigeration, dormancy, and control of the temperature in the greenhouse to 2-4°C without light; 4) during the germination period in May, gradually increase the temperature, turn on the insulation cotton, and control the temperature in the greenhouse to 10-20°C; 5) during the flowering period from May to June, simulate the normal temperature of spring, and control the temperature in the greenhouse to 12-25°C; 6) during the young fruit period from mid-June to early July, control the temperature in the greenhouse to 20-25°C, and use supplemental light and natural light for photosynthesis; the supplemental light uses Zhicai supplemental light, the red-to-blue light ratio is 1.8, 1 m x 0.75 m high-density supplemental light is used to supplement light, the distance between the supplemental light and the leaves is 20-80 cm, and during the supplement period, the temperature in the off-season cultivation greenhouse is controlled in the range of 20-25°C; the supplemental light is automatically turned on when the natural light is lower than 930 Lux; the Zhicai supplemental light has a power of 60 W, a main wavelength of 699.0 nm, and a light flux of 4030.42 1m, and the supplemental light time is from 6:00 to 22:00 every day; 7) during the maturation period from July to August, control the temperature in the greenhouse to 18-28°C; 8) during the post-harvest period from September to October, do not use the refrigerator, turn on the insulation cotton, open all the greenhouse films, and normally manage and strengthen the fertilizer and water management; wherein the high-temperature-resistant sweet cherry variety is "Qi Zao" or "Mei Zao"; during the young fruit period, the temperature in the "Qi Zao" off-season cultivation greenhouse is controlled to 20°C, and the temperature in the "Mei Zao" off-season cultivation greenhouse is controlled to 25°C.

2. The method of claim 1, wherein, "Qi Zao" is a 5-year-old KGB tree shape, and "Mei Zao" is a 4-year-old fine high spindle tree shape.

3. The method of claim 1, wherein, According to the method of claim 1, the off-season cultivation greenhouse is a single-arched shed, the shed length is 40 m, the shed width is 11 m, and the outside of the shed is covered with 5 cm thick rubber plastic insulation cotton.

4. The method of claim 1, wherein, The installation height of the supplemental light is 40-120 cm, and the height is arranged staggered according to different tree shapes to ensure the uniformity of the photosynthesis of sweet cherries.

5. The method of claim 1, wherein, Fertilization management includes the application of urea, potassium dihydrogen phosphate, and trace element fertilizer, and nutrients are supplemented in stages to ensure the improvement of leaf photosynthetic efficiency and fruit quality.

6. The method of claim 1, wherein, The temperature, humidity, and light intensity in the greenhouse are monitored in real time by a remote monitoring instrument to ensure that the growth environment of sweet cherries is always in the best state.

Images