Key points of the soilless short-stem cutting technique for tea plants

Soilless short-stem cutting of tea plants not only saves costs compared with the traditional short-stem cutting with a soil core layer, but also achieves a cutting survival rate of up to 85%, giving it considerable value for wider promotion.

1. Nursery site preparation (1) Plot selection. The nursery site should be close to a water source, with loose soil and flat terrain, and easy to drain and irrigate. (2) Planning. Adjust measures to local conditions, dividing the site into blocks according to the natural drop of the plot. A drainage and irrigation ditch should be dug around each block, 60 cm wide and 40 cm deep. The beds are generally 10-15 m long and 1 m wide, with a working ditch 40 cm wide between beds, and an east-west bed orientation is preferable. (3) Prepare the seedbed well. After setting out the lines around the bed, first dig off the topsoil (to a depth of 10 cm), shovel up all the topsoil and place it to one side, then dig the subsoil (to a depth of 10 cm) and place it on the other side, then backfill all the topsoil and level it. Mix the prepared insecticide, fungicide and base fertilizer thoroughly, then spread them evenly over the backfilled topsoil (per square meter use 8 g of carbofuran, 1.5 g of thiophanate-methyl, and 450 g of cake fertilizer), then backfill the subsoil as topsoil, level it, and tamp it firm. (4) Furrow irrigation. After the seedbed is prepared, carry out continuous furrow irrigation. Furrow irrigation can kill insect eggs, allow the fungicide to fully penetrate the soil, and fully decompose the cake fertilizer. This process takes about 20 days.

2. Build shade facilities. A 1.8 m high flat-topped shade frame gives a relatively good shading effect. Method for building the flat-topped frame: using each block as a unit, set out lines and bury posts, with a lateral spacing of 6-8 m and a longitudinal length equal to the bed length. About 25 posts are needed per mu (2.5 m long moso bamboo can be used, buried 50 cm deep), and each post must be tamped firmly layer by layer with stones and soil. After the posts are buried, secure them with iron wire, and cover the wire with a shade net.

3. Cutting (1) Cut the cuttings. The cuttings must be thick, semi-lignified, red-brown branches. Cuttings should preferably be taken in the morning, and after being cut back they must be inserted immediately. The length of the cuttings is generally preferably 3.3-4 cm. For a long internode, cut one internode (one leaf and one bud) as one cutting; for a short internode, two internodes can be cut as one cutting, with the lower leaf removed and the upper leaf retained. The small stub left above the leaf must not be too short, generally 3-4 mm, with the upper cut surface slanting outward to avoid water accumulation and rot, and the lower cut surface cut into a horseshoe shape. (2) Insertion. Two hours before insertion, sprinkle water to soak the bed surface thoroughly, then mark out rows. For small- and medium-leaf tea varieties, the row spacing is generally 7-10 cm. After marking rows on the bed surface, spray 170 mL of the herbicide butachlor mixed with 55 kg of water per mu, then insert the cuttings, with plant spacing such that the cuttings do not shade each other and no soil is visible after insertion. After insertion, press lightly between the cuttings with your fingers. The insertion angle is generally preferably 35-45 degrees between the leaf and the ground; the leaf should not lie flat on the ground, otherwise leaf respiration will be affected. After insertion is completed, sterilize with a 1000-fold dilution of carbendazim. Finally, insert bamboo arches (2.2 m long) on the bed, with the center at least 50 cm above the bed surface, cover the bamboo arches with plastic film, and press the edges firmly with soil to form a small arch shed, which can preserve heat and moisture and help the cuttings heal and root.

4. Nursery management (1) Water management. After insertion is completed, irrigate promptly with furrow irrigation for 20 hours. Routine water management should depend on soil moisture, generally keeping the topsoil moist. If the topsoil is dry and loose, furrow irrigation should be carried out promptly. (2) Temperature management. When cutting in autumn (mid- to late September to early October), daytime temperatures are still relatively high, and plastic film is also used for covering. The daytime temperature inside the small arch shed is generally 28°C-34°C, and the maximum temperature can sometimes reach 42°C. Once the temperature exceeds 42°C, the leaves will be scorched, so ventilation and heat dissipation must be carried out promptly (open the film at both ends). In late March of the following year, observe temperature changes at all times and adjust promptly. (3) Remove flower buds. For autumn cuttings, there are many flower buds, which must be removed promptly. When removing flower buds, dissecting scissors or pointed scissors can be used, and the buds must not be damaged or the cuttings loosened. Removing flower buds can be done at the same time as ventilation or spraying. (4) Fertilization. Fertilization is generally carried out in late April. As the temperature gradually rises, the cuttings continuously produce large numbers of new roots, and tea buds also sprout abundantly, so large amounts of fertilizer and water are needed at this time. After May 20, once 85%-95% of the cuttings have rooted, the plastic film on the small arch shed can be removed. The first foliar spray uses 0.5% urea; the second foliar spray uses 1% urea plus Pen Shi Bao (an interval of 7-10 days); the third spray uses 2% urea plus Pen Shi Bao. After June 20, as the cuttings gradually grow and their resistance increases, organic fertilizer can begin to be applied: put 1 part cake fertilizer and 10 parts water into a pit and let it fully decompose (about 20 days), then take 1 part cake fertilizer water and add 10 parts water to irrigate the tea seedlings, once every 15-20 days. In this way, the tea seedlings can reach 70 cm in height in the same year. (5) Hardening off. After August, the temperature gradually drops, and the shade net on the flat-topped frame should be gradually removed. In the Dabie Mountains area, there are often partly cloudy days, and this opportunity can be seized for hardening off the seedlings.