To enable Tea trees to better withstand low-temperature frost damage in winter, it is essential to strengthen their internal nutrition. With a certain level of resistance, they can adapt better to changes in external temperatures.
During the growth and development period of tea trees, focus on enhancing nutrient content and soil fertility, allowing the tea trees to grow stronger and accumulate more nutrients. In autumn and winter, concentrate on applying base fertilizers.
The application of base fertilizers should primarily consist of farmyard manure, supplemented with potassium and phosphorus fertilizers, as well as sheep and cow manure. These fertilizers generate some heat, which can increase surface soil temperature. Tea trees have sufficient nutrients during their brief dormancy in winter, enabling them to successfully survive the cold season.
Applying excessive nitrogen fertilizer in autumn can stimulate vigorous growth in tea trees, delaying their entry into dormancy. This results in soft and tender branches and leaves that are less resistant to low-temperature frost damage.
In winter, mound up the soil around the roots of tea trees to a height of seven to nine centimeters. This improves soil structure, with particularly noticeable effects on plots with shallow soil layers.
I. Measures Against Frost Damage
1. Mounding Soil
Mound soil in the tea garden before winter arrives. If mounding is done too late when temperatures are too low, it will not be effective. For tea gardens on slopes, mound more soil at the lower end where the tea trees are planted to prevent root exposure. This prevents cold winds from invading, and the soil can be overturned again in February.
2. Covering with Straw
Straw such as wheat stalks and rice straw can be spread between rows of tea plants for insulation. When covering with straw, increase the thickness closer to the root area of the tea trees.
This practice raises the surface soil temperature and prevents it from becoming frozen and hard, ensuring normal Water circulation in the soil.
3. Fumigation
Before the arrival of frost and cold waves, when environmental temperatures drop significantly, set up bonfires in the tea garden according to wind direction and terrain. Burn straw to create smoke, which disperses the cold air and protects against frost and low temperatures. Under certain conditions, greenhouses can also be constructed.
4. Ventilation Facilities
Fans used to prevent frost damage can avoid injury to young shoots due to frost at night. They circulate warm air from the upper atmosphere down to the surface, typically installed seven to nine meters above ground level.
The temperature in the air is four to six degrees higher than near the surface, so install frost-preventing fans seven meters away from the tea trees to conduct warmer air onto the greenhouse surface.
5. Anti-Freeze Agents
Anti-freeze agents adjust the activity of hormones and enzymes within tea trees, encouraging the production of substances that resist low temperatures and enhance cold tolerance.
Additionally, they supplement necessary nutrients, regulate stomatal gaps, inhibit unnecessary transpiration, balance nutrient distribution, and promote healthier root growth. They also stabilize cell membranes, increase chlorophyll content, and regulate photosynthesis and respiration. Apply anti-freeze agents when temperatures stabilize around 12 degrees Celsius, once every week for three to four times.
Applying anti-freeze agents before leaves turn yellow replenishes nutrients, promotes better differentiation of flowers and buds, and benefits growth and development the following year. At this time, also perform garden management to eliminate pests and diseases.
Apply anti-freeze agents when the temperature in the tea garden stabilizes above seven degrees Celsius to prevent freezing after application, which would not only fail to protect against frost damage but could also cause further harm.
Fertilizers should be applied by digging trenches, placing farmyard manure 35 centimeters deep, and adding additional fertilizers in trenches 20 centimeters deep. Digging trenches improves air circulation in the tea garden, benefiting root growth.
II. Field Management
1. Planting Green Manure Crops
Green manure crops can also be planted in the tea garden. Choose tall varieties that can withstand acidic and poor soils. To prevent nutrient loss due to rainwater runoff, plant creeping green manure crops. They can shade the tea garden, protect against frost damage, and be selected for their strong resistance to cold.
2. Fertilization
Apply farmyard manure such as oil residues, Cake fertilizers, human and livestock excrement, compost, and humic acid fertilizers, ensuring they are fully matured through fermentation to avoid burning the roots of tea trees.
Select fertilizers that support sustainable growth and ensure high-quality tea leaves. Proper fertilization maintains a healthy growing environment and improves soil fertility. Avoid improper use of inorganic fertilizers that can lead to soil salinization and accumulation of toxic substances. Do not use fertilizers contaminated with heavy metals or infected with pathogens; instead, use farmyard manure that has been thoroughly matured through high-temperature fermentation.
Through pruning, damaged parts can be removed, promoting faster regrowth of new branches and leaves. Adjust the shape of the canopy to evenly distribute nutrients and encourage the growth of lateral branches. When many slender shoots and leaves appear on the surface of the canopy, trim off the top 12 centimeters of leaves. Additionally, when temperatures approach zero, spray water to prevent frost damage.
Tea gardens with suitable conditions can install ventilation facilities to reduce frost damage through the circulation of air and surface currents.
Source: Uncle Han Talks About Agriculture. Information is valuable when shared.