Detailed Explanation of Key Cultivation Techniques and Planting Management Methods for Camellia japonica

Seed collection. The fruit of Camellia japonica matures from late October to early November. When the berry-like capsule turns from yellow-green to yellow-brown, the upper part slightly splits, the aril turns red, and the seed kernel is plump, collect it promptly. After collecting the fruit, place it in a ventilated indoor area and spread it out to air for 2-3 days to complete after-ripening. Then take it out to a concrete surface outdoors, tread on it with feet to crack open the fruit shells, remove the seeds, soak them in clean water for 24 hours, rub off the red aril, float away empty seeds, scoop them out and dry them for 2-3 days. Sow immediately after collection or store in moist sand. When storing seeds, be careful that the sand is not too wet, so as to avoid seed rot.

Choose a good nursery site. The nursery site should be selected in a place with good drainage, convenient irrigation, and deep, fertile, moist soil. The land preparation method is the same as for conventional seedling cultivation. Apply 100 kg of superphosphate, 100 kg of high-quality compound fertilizer, 200 kg of barnyard manure, and 5 kg of furadan per mu. After mixing evenly, incorporate it into the seedbed during land preparation. The nursery site should be deeply plowed and finely prepared, with soil clods broken up finely.

Sowing and seedling cultivation. Sowing can be divided into winter sowing and spring sowing. For winter sowing, after seed treatment, disinfect with a 0.5% potassium permanganate solution for 30 minutes, then rinse clean with water and sow. Sowing immediately after collection can reduce the trouble of seed storage, has a high seed germination rate, earlier seedling emergence, and good seedling quality, but requires more nursery management labor. Spring sowing is from March to April. After the seeds have been stored, carry out moist sand stratification to promote germination. When some seeds have cracked and shown white, they can be sown. This can advance seedling emergence and save labor.

Sowing method. Drill sowing is commonly used, with row spacing of 20-25 cm and sowing furrow depth of 4-5 cm. Place a 2-3 cm layer of yellow subsoil in the furrow, then sow the seeds evenly into the furrow, cover the seeds with yellow subsoil, with a thickness such that the seeds are no longer visible, and cover with rice straw to retain moisture.

Timely shading. Camellia japonica seedlings prefer shade and are afraid of sunscald. Under appropriate shading conditions, the seedlings grow rapidly, and one-year-old seedlings can reach 40-50 cm in height. After the seedlings emerge, the temperature begins to rise. From late April to early May, set up a shed frame 1.8 m high and cover it with a shade net with 60% shading to promote seedling growth.

Cultivation and weeding. Camellia japonica prefers deep, loose soil, so the nursery site should be frequently cultivated and weeded to keep the soil loose. At the same time, pay attention to draining accumulated water to prevent root rot.

Fertilize frequently. Camellia japonica has well-developed fibrous roots and large leaves, and has a high fertilizer requirement, so it should be fertilized frequently. During the leaf expansion period from May to June, apply 0.5% urea water once every half month; in July, apply topdressing in combination with drought resistance; from August to September, which is the peak growth period of the seedlings, apply 1-2 times of human feces and urine; stop fertilizing in late September.

Pest and disease control. Diseases include root rot and sunscald. Root rot is caused by high temperature and high humidity. The control method is to drain accumulated water and drench the root base with 1% green vitriol solution, then rinse the seedlings with clean water after 15 minutes to avoid phytotoxicity. For sunscald, provide timely shading. In the early stage of the disease, spray 0.125% thiophanate continuously twice for good control results. Pests include cutworms and scarab beetle larvae that damage aboveground and underground parts. They can be controlled by drenching the root base with 0.125% omethoate, or by manual capture in the morning and evening.