Detailed Explanation of Key Technical Points for Greenhouse Tea Plant Cultivation and Management

Covering tea gardens with plastic greenhouses is an important cultivation and management technique for advancing the harvest time of famous premium tea, improving quality, and significantly increasing economic benefits. The main function of the greenhouse is to preserve heat and prevent frost and freezing damage. Generally, the film is erected and covered from late October to late December of the previous year before frost arrives, and can be uncovered in early to mid-April of the following year.

Greenhouse Environment Management

The temperature most suitable for tea growth inside the greenhouse is 20°C-25°C, with the maximum not exceeding 30°C and the minimum not falling below 8°C. On sunny days at noon, the temperature inside the greenhouse may exceed 30°C, and at this time the door or ventilation openings must be opened to cool it down; when the temperature drops to 20°C, the ventilation openings should be closed promptly; at night the temperature drops rapidly, so attention must be paid to heat preservation, especially on particularly cold overcast and rainy days or windy days. Because the greenhouse is in a sealed state, tea plant respiration and decomposition of soil organic matter will cause great changes in the gas composition inside the greenhouse, affecting tea plant growth, so proper ventilation should be carried out every day; generally, under the condition that the greenhouse temperature is not lowered below 8°C, open the ventilation openings or door curtain at 10 a.m. and close them at around 3 p.m.

After the greenhouse is built, if there is heavy rain, wind, snow, or other weather, timely inspections should be carried out. If there is tilting, damage, air leakage, rain leakage, etc., reinforcement and patching should be carried out promptly. If there is accumulated snow on the greenhouse roof, it must be removed promptly to prevent the film from being crushed or the greenhouse frame from collapsing.

Greenhouse Tea Plant Cultivation and Management

Apply sufficient base fertilizer: Because the temperature inside the greenhouse is high, the original dormancy habit of the tea plant is changed, causing the aboveground part of the tea plant to remain in a certain active state in autumn, winter, and early spring, so sufficient base fertilizer must be applied before the greenhouse is built. The fertilizer type should be mainly decomposed organic fertilizer, mixed with a certain amount of inorganic fertilizer, such as Zhongcha No. 1 tea-specific fertilizer, etc.

Apply bud-promoting fertilizer early: Greenhouse tea plants sprout early in spring and are not threatened by late frost. Therefore, early spring topdressing should be carried out as early as possible to promote the germination of overwintering buds. The bud-promoting fertilizer should be applied well in early to mid-February.

Apply foliar fertilizer frequently: To prevent nutrient deficiency in tea plants in the greenhouse, provide comprehensive nutrition to the tea plants, promote healthy growth of tea plants and early sprouting, from after film covering to before film uncovering, multifunctional foliar nutrient solutions that contain multiple nutrient elements and can promote growth must be sprayed frequently, such as "Ainong," "Gaomeishi," "Yemianbao," and "Tianyuan," etc.

Timely irrigation: The soil inside the greenhouse receives greatly reduced atmospheric precipitation, so the soil water content in the tea plant root distribution layer is much lower than that of open-air tea gardens. During the covering period, each greenhouse can, according to local water sources and terrain conditions, generally use a sprayer for manual spray irrigation every 5-8 days, or use methods such as carrying water for watering or channel irrigation to ensure the water demand for normal tea plant growth.

Apply additional carbon dioxide gas fertilizer: In the greenhouse on sunny days, photosynthesis is strongest from 9 a.m. to 3 p.m., and the carbon dioxide concentration is lowest. At this time, the intensity of photosynthesis is often reduced due to lack of carbon dioxide, affecting tea plant growth and tea quality. Therefore, carbon dioxide gas fertilizer should be applied in greenhouse tea gardens. High-pressure liquid carbon dioxide from a steel cylinder can be slowly poured from the gas valve into a sealed plastic bag (leaving one air inlet, with a volume of about 0.5 cubic meters). After the plastic bag expands and is filled with gas fertilizer, tie the bag opening tightly, and place 2 bags of carbon dioxide gas fertilizer per mu of greenhouse tea garden. At around 9 a.m. every day, place them at equal distances between tea rows, open the sealed openings of the plastic bags, and retrieve them at 4 p.m., then refill them with carbon dioxide in the original way and apply continuously. Using this method can increase the carbon dioxide concentration in the greenhouse tea garden by more than 2 times. Special carbon dioxide granular fertilizer can also be applied.

Combine cultivating and hoeing with straw mulching: The temperature inside the greenhouse is high, and weeds are likely to grow and reproduce. After the autumn tea harvest, cultivating and hoeing should be carried out once in combination with base fertilizer application, and straw should be spread between tea rows. Use various mountain weeds, crop stalks, etc. as straw sources, 500-600 kg per mu, spread to a thickness of 10-15 cm, and press an appropriate amount of soil on the straw. In the autumn of the following year, deeply plow and bury it into the soil, which can both preserve moisture and increase temperature, and improve the soil and increase fertility.

Reasonable pruning and picking: For greenhouse tea gardens, conventional pre-spring tea pruning (such as light pruning, deep pruning, etc.) should be postponed until after the spring tea ends or after the summer tea. Control tree height at about 80 cm. After autumn tea, combine with early garden closure to carry out one light pruning and edge pruning, arranging the canopy surface to facilitate ventilation, light penetration, and nutrient accumulation in tea plants. Carry out deep pruning every 2-3 years and heavy pruning every 5-8 years to rejuvenate tree vigor. Every year, deep pruning of the tea garden in autumn and winter must be avoided, so as not to affect the early and abundant sprouting of spring tea buds and leaves the following year.