Detailed Explanation of Short-Cutting Propagation Techniques for White Tea

White tea propagation generally adopts the asexual short-cutting propagation technique. Tests have shown that when white tea is propagated from tea seeds, the offspring exhibit trait variation, meaning they lack the characteristic of periodic spring re-whitening. Using short-cutting propagation can maintain the characteristics of the mother plant, produce uniform offspring traits, and achieve a high propagation coefficient and survival rate. Considering the economic benefits of white tea, at present, no dedicated mother plant garden is established; instead, the mother plant garden and the picking garden are combined. Cutting is generally carried out in autumn from September to October, as during this period the cuttings root quickly, the seedling formation rate is high, and the management period is short, which helps reduce production costs.

I. Cultivation of Mother Trees for Cutting Collection

After spring tea picking, the white tea mother trees are pruned immediately, removing chicken-claw branches and thin weak branches from the canopy surface, with the pruning depth being such that vigorous shoots can grow out. Fertilizer management should be strengthened. On the basis of applying sufficient nitrogen fertilizer (at the same application rate as an equivalent production tea garden), the application rates of phosphorus and potassium fertilizers should be increased to enhance the branching ability of new shoots. Pest and disease control should be strengthened to ensure that the new shoots, branches and leaves of the mother trees are robust and intact. If it is expected that the tips of the cutting branches will not have formed dormant buds by the time of cutting, topping should be carried out 10-15 days before cutting the shoots, artificially forcing the shoots to stop growing and promoting their maturation. The production index for cuttings is preferably reddish-brown, and green hard branches are also good.

II. Selection and Preparation of Nursery Land

The nursery land should be selected from farmland or paddy fields with convenient transportation, flat terrain, sufficient water sources and convenient drainage. The soil quality should be loose, slightly acidic sandy or light clay loam. Land previously cropped with tobacco, hemp or vegetables is not suitable for use as a nursery. The nursery land should be thoroughly deep-plowed and carefully made into beds, with a bed surface width of 100-200 cm, a bed ditch width of 30-40 cm, and a tunnel height of 15-20 cm. Drainage ditches should be opened around the nursery land. Generally, 100-150 kg of decomposed cake fertilizer per mu is applied to the nursery land, together with 20 kg of superphosphate. The fertilizer should be mixed evenly with the bed surface soil. Then a 5-6 cm thick layer of loose red soil or yellow soil subsoil is spread on the bed surface. After spreading evenly, it is slightly compacted for later use during cutting.

III. Cutting Shoots and Inserting Cuttings

The branches cut from the white tea mother trees should be placed in a cool, moist place to prevent excessive water loss. Shoots should be cut and cuttings inserted on the same day. The cut shoots should be about 3 cm long, and each shoot should have 1 plump axillary bud and 1 healthy true leaf. The cut must be smooth, and the slant direction of the cut should be consistent with the direction of the leaf.

Cutting is generally carried out before 10 a.m. or when the sunlight weakens in the afternoon. First, spray the bed surface thoroughly to moisten it. When the soil no longer sticks to the hand, insert the cuttings vertically or obliquely into the soil at a row spacing of 7-10 cm, with the depth such that the leaf petiole is exposed. While inserting, press the soil slightly firm. The plant spacing depends on the leaf width, and it is best to keep the leaves from overlapping and shading each other. About 150,000 cuttings are inserted per mu of nursery. Water thoroughly immediately after cutting.

IV. Building Shade Frames

Building shade frames over the nursery land can avoid strong direct sunlight, reduce ground wind speed, and decrease water evaporation, which helps improve the survival rate of cuttings and the growth of seedlings. Generally, shade nets are used for covering, with a frame height of 35-50 cm. The shade frame should be covered immediately after cutting.

V. Nursery Management

1. Watering and drainage. Before the cuttings have rooted, water frequently to keep the soil moist and increase air humidity. On sunny days, water once in the morning and once in the evening; on cloudy days, water once a day; on rainy days, watering may be omitted, and attention should be paid to drainage after heavy rain. After the cuttings have rooted, water once every other day or every few days, keeping the soil moist.

2. Management of shade frames. The shade frames should be inspected and repaired in time, and after rooting, the light transmittance should be increased. Because white tea has relatively poor cold resistance, film should be added when winter arrives to increase ground temperature, and it should be removed when the temperature rises the following year.

3. Timely weeding and removal of flower buds. Weeds on the bed surface should be pulled out by hand in time. Weeds in the bed ditches can be killed by spraying herbicide, but the herbicide must not come into contact with the cuttings. Flower buds on the tea seedlings should be removed by hand in time.

4. Timely fertilization. Although seedlings can absorb some nutrients from the soil, because the initial root system is sparse, appropriate topdressing is necessary. Fertilization should be carried out in stages and multiple times. When the cuttings have grown to 3-4 cm and formed the first leaf group, the first fertilization begins, and thereafter once a month. The fertilizer should preferably be dilute and light, generally applied together with watering.

5. Pest and disease control. Common pests and diseases at the seedling stage include small green leafhoppers, tea aphids and leaf diseases, etc. Insecticides or fungicides should be sprayed in time. Spraying should be done after watering, once the leaf surface is horizontal.

VI. Lifting Seedlings

White tea seedlings from autumn cutting can generally be lifted and planted from October to November of the following year. The quality of the seedlings is based on the "Anji White Tea Standard"; seedlings of grade two or above must reach a seedling height of 20-30 cm, stem thickness of 1.8-30 mm, root length of 4-12 cm, and 6-8 leaves, with no quarantine pests or diseases.