Detailed Explanation of Key Techniques for Tea Cultivation in High Mountain Areas

Datian County has over 20,000 mu planted in high mountain areas at an altitude of 800-1,100 m. This region has an annual average temperature of 17.5°C, annual rainfall of 1,770 mm, large day-night temperature differences, abundant cloud, mist and dew, and high humidity. The annual picking period starts 7-10 days later than the low-altitude tea areas in the county, and autumn tea ends about 7 days earlier. Therefore, the following technical points must be mastered in production and cultivation.

I. Seedlings

1. Variety selection: choose superior varieties with strong cold resistance, drought resistance and pest and disease resistance, favorable to market competition and cultivation direction, and suitable for the local environment and climate. Such as Tieguanyin, Mingke No. 1, Jinxuan and other varieties.

2. Seedling selection: choose one-year-old robust seedlings with a height greater than 20 cm, stem diameter greater than 2 mm, a certain number of leaves, vigorous roots, and no pest or disease damage. They have 1-2 first-level branches, which lays the foundation for rapid growth of the tea plant, early formation of the plantation and early production.

II. Planting

1. Planting time

Planting should be carried out during the growth period of underground activity, which is beneficial to root elongation and development, and also beneficial to absorbing soil nutrients to supply the nutrients needed for the beginning of aboveground growth. The planting time for tea seedlings in high mountain areas should be in February each year (around the Spring Festival).

2. Technical methods

In the planting ditch of the prepared tea garden, use planting tools to dig holes 10-12 cm deep with a hole diameter of more than 10 cm, plant the tea seedlings vertically in the holes, fill with soil and press firmly, or use tools to compact the soil layer on three sides of the seedling stem, then cover with 1-2 cm of fine soil and water thoroughly. When planting, the seedlings should be set 1-2 cm deeper than normal. It is most ideal if planting can be chosen before rain. Tea seedling planting should adopt the "double-row single-plant" method, with a plant spacing of 30 cm, and plants arranged in a triangle between rows. Spread 3-5 cm thick rice straw or other grasses in the tea rows of the planting ditch for mulching, which helps keep warmth and moisture and also inhibits weed growth.

III. Pruning

1. Pruning time

The pruning time should preferably be in late May or early June, and after the end of autumn tea in mid-October.

2. Pruning techniques

(1) Formative pruning: its purpose is to cultivate a reasonable tree framework and high-yielding canopy during the young stage of the tea plant. Generally carried out 4 times, and the new shoots at the cutting point of each formative pruning must be lignified or semi-lignified. The first pruning is combined with planting and cut at 15-18 cm above the ground; the second, third and fourth formative prunings require cutting 15 cm above the previous pruning cut. After four formative prunings, the tree height has reached 60 cm, with a 2-3 level branching structure, initially forming a reasonable picking canopy, and can then be put into production.

(2) Light pruning: the purpose of light pruning is to adjust the canopy and cultivate a good picking surface. It is carried out once a year, and the degree of light pruning is to cut off 3-5 cm from the canopy surface, mainly removing small stubs, useless new shoots, etc. on the canopy surface.

(3) Deep pruning: for trees that have undergone many years of picking and light pruning, the deep pruning method should be used to cut off a 10-15 cm layer of branches and leaves from the upper part of the canopy, so that the tea plant sends out new branches again, improves the sprouting ability of the tea plant, and prolongs the number of years of high and stable yield.

(4) Heavy pruning: for semi-aged and prematurely aging tea plants, it is generally appropriate to cut off 1/2 of the original tree height, combined with cleaning up (thinning pruning), to re-cultivate robust branches and trunks and a picking canopy.

(5) Collar pruning: for very aged tea plants, it is appropriate to saw (or cut) off all branches and trunks at about 10-15 cm above the ground, and re-cultivate the tree framework structure and picking canopy.

IV. Fertilizer management

1. Apply sufficient base fertilizer (bottom fertilizer): organic fertilizers such as farmyard manure, cake fertilizer, commercial organic fertilizer, etc. should be applied to the planting ditch before planting and every winter after production begins. Commercial organic fertilizer is mainly used, applied at 200-300 kg per mu.

2. Multiple topdressings: carried out three times in early March, mid-to-late May, and mid-August in combination with shallow tillage operations. Mainly N, P, K compound fertilizer, applied at 40-60 kg per mu.

3. Technical requirements: open a strip ditch 15-20 cm deep below the edge of the canopy (20-25 cm deep when applying base fertilizer), apply fertilizer evenly in the ditch, and cover with soil after application.

4. Tillage and weeding: production tea gardens should carry out 2-3 times of 10-15 cm shallow tillage and weed removal each year during the non-picking season, and deep tillage of 20-25 cm in mid-October to loosen the soil.

5. Pest and disease control: based on agricultural control, regulate the ecological environment in the tea garden and suppress the occurrence and damage of pests and diseases. Spray 0.5 degree Baume lime sulfur mixture every winter to close the garden and reduce the density of pests and diseases the following year. During the non-picking season, according to the occurrence of diseases, pesticides such as Score, thiophanate-methyl, and half-strength Bordeaux mixture can be used for control. Use highly toxic, highly effective, low-residue (or residue-free) pesticides such as Uranus, Kung Fu, imidacloprid, matrine, rotenone, etc. The use of pesticides must strictly follow the safety interval, and the use of highly toxic, high-residue and pesticides explicitly prohibited by the state must be eliminated.