III. Controlling Light Conditions for Blueberries in Greenhouses
1. Use of Shade Nets: Shade nets can be used to regulate light intensity, ensuring that blueberries are not exposed to overly strong sunlight.
2. Shade Nets: These help to reduce light intensity and provide suitable lighting conditions, preventing blueberries from overheating and slowing down photosynthesis.
3. Supplemental Lighting: In seasons or during cloudy days when light is insufficient, supplemental lighting can be used to ensure blueberries have enough light for photosynthesis.
4. Supplemental Lighting: Supplemental lights can provide a spectrum similar to natural light, helping blueberries maintain good growth in environments with insufficient light.
5. Control of Light Intensity: Blueberries' photosynthesis is closely related to light intensity; both too strong and too weak light are detrimental to blueberry growth.
6. Light Intensity Control: Therefore, it is necessary to adjust light intensity according to the growth stage and specific needs of blueberries to achieve optimal photosynthesis efficiency.
7. Management of Light Duration: Blueberries have varying light duration requirements at different growth stages, and it is important to control light duration reasonably to promote both vegetative and reproductive growth.
8. Light Duration Management: For example, during the seedling stage of blueberries, light duration can be appropriately reduced to avoid damage from strong light.
9. Coordination of Greenhouse Temperature and Light: The temperature inside the greenhouse also affects blueberry photosynthesis, and it is necessary to adjust the indoor temperature according to light conditions to ensure the most suitable environment for blueberry growth.
10. CO2 Concentration Regulation: An appropriate increase in CO2 concentration in the greenhouse can enhance photosynthesis efficiency, so while adjusting light, attention should also be paid to supplementing CO2.
IV. Balancing Temperature and Light in Greenhouses for Blueberries
1. Temperature Management: Temperature management for blueberries in greenhouses is a delicate balancing act. After blueberries enter natural dormancy, they require a certain number of hours of low temperatures to flower and bear fruit normally. For instance, in the Qingdao area, the time when the temperature steadily passes 7.2℃ is around November 20th. The time to cover the greenhouse and raise the temperature should be November 20th plus 34 days plus a safety margin of 3-5 days, which means the safe period for covering and warming the greenhouse is from December 27th to 29th. Additionally, the temperature inside the greenhouse should be adjusted according to the growth stage of the blueberries to ensure normal growth and development.
2. Light Management: Blueberries need ample light for photosynthesis, but too strong light can damage the plants. In greenhouses, light intensity can be regulated using shade nets to ensure blueberries are not exposed to overly strong sunlight. Reflective films can also be used to increase light intensity, especially during winter when daylight hours are short.
3. Ventilation and Humidity Control: Ventilation and humidity control inside the greenhouse are equally important for blueberry growth. Proper ventilation can help lower the temperature inside the greenhouse, reduce the occurrence of pests and diseases, and maintain suitable humidity levels. During the blueberry growing season, the air relative humidity inside the greenhouse should be kept at 70%-75%, which is conducive to blueberry sprouting.
4. CO2 Concentration Regulation: An appropriate increase in CO2 concentration in the greenhouse can enhance photosynthesis efficiency, so while adjusting light, attention should also be paid to supplementing CO2.
Through the above measures, the balance of temperature and light in the greenhouse can be effectively managed, providing an optimal growing environment for blueberries and improving their yield and quality.
V. How Many Hours of Low Temperature Does Blueberry Need During Dormancy?
After entering dormancy, blueberries require a certain period of low temperatures to break physiological dormancy, known as the chilling requirement. Different blueberry varieties have varying chilling requirements. For example, the 'ReKa' variety requires 1000 hours or more of chilling, and the 'DuKe' variety also requires 1000 hours. Some varieties have lower chilling requirements, such as the 'Meadowlark' variety, which requires less than 900 hours, while the 'Green Gem' variety requires over 250 hours. Additionally, the 'Eureka' variety requires no more than 100 hours, the 'Rocio' (H5) variety requires no more than 60 hours, and the 'L' variety requires no more than 80 hours. These chilling requirement data are crucial for managing blueberry dormancy to ensure normal plant growth and fruiting.
VI. Besides Chilling Requirements, What Other Factors Affect the Release of Blueberry Dormancy?
The release of blueberry dormancy is influenced by multiple factors, in addition to chilling requirements, including:
1. Exogenous Hormones: Exogenous gibberellins (GA) can effectively break blueberry bud dormancy. Studies have shown that exogenous GA treatment can significantly reduce starch content and increase flower bud water content, thereby promoting the release of blueberry dormancy and sprouting.
2. Temperature Management: After entering dormancy, blueberries require a certain period of low temperatures to break physiological dormancy. In greenhouses, temperature can be controlled to simulate the low-temperature needs of natural conditions, helping blueberries to break dormancy.
3. Light Conditions: Light also affects the release of blueberry dormancy. Although blueberries are light-loving plants, too strong light during dormancy can damage the plants. Therefore, proper light management is also an important aspect of dormancy release.
4. Water Management: During blueberry dormancy, appropriate water management is necessary. Maintaining suitable soil moisture helps blueberry plants stay healthy during dormancy.
5. Nutrient Management: During dormancy, blueberries have relatively low fertilizer requirements, but proper nutrient management can help the plant grow better after dormancy ends. Foliar fertilizers can be applied to provide necessary nutrients.
6. Pest and Disease Control: During dormancy, blueberry plants are weaker and more susceptible to pests and diseases. Therefore, timely pest and disease control is an important factor to ensure plant health and smooth dormancy release.
7. Pruning Management: Proper pruning can promote the growth and fruiting of blueberry plants. Pruning during dormancy can remove dead and crossing branches, maintaining good air circulation and light penetration, which helps the plant release dormancy.
Through the above measures, the dormancy period of blueberries can be effectively managed, ensuring that the plants can grow healthily after dormancy, and improving the yield and quality of blueberries.
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Post time: Nov-12-2024
