Angelica (Angelica sinensis) is a medicinal plant widely cultivated in China, but one of the major challenges farmers face is premature bolting—when the plant flowers and goes to seed before it's ready for harvest. This not only reduces yield but also affects the quality of the root, which is the most valuable part of the plant. Understanding the reasons behind early bolting is essential for effective prevention and control.
One key reason for early bolting is the use of low-quality or improperly selected seeds. Farmers often use seeds that have already bolted, such as "flower seeds" or "fire seeds," which are more likely to bolt quickly after sowing. These seeds tend to develop faster, with some seedlings bolting 10–15 days earlier than others. The high bolting rate—up to 30–40% higher—can be attributed to the fact that these seeds are mature and have strong developmental potential, making them prone to rapid transition into reproductive growth.
Another factor is improper timing of seedling cultivation. If seedlings are grown too early, they may become overly large and develop long roots, which can trigger premature bolting. Angelica seedlings typically require 90–110 days of growth, reaching a fresh weight of 40–70 grams. Sowing is best done between mid-June and mid-July, allowing the seedlings to enter dormancy by autumn. Delaying planting can lead to weak, tender seedlings that struggle to survive the winter.
Seedling size also plays a role. Larger or older seedlings are more likely to bolt prematurely when transplanted. Farmers in Yao County, for example, prefer seedlings with a diameter of less than 0.5 cm to reduce bolting risk. However, seedling size must match its age—very small or very large seedlings may still bolt if not properly managed.
Environmental conditions significantly influence bolting. Drought, poor soil fertility, excessive shade, and high temperatures can accelerate the plant’s development, causing it to bolt earlier. Angelica requires specific conditions to transition from vegetative to reproductive growth: a vernalization stage at 0–5°C and an illumination stage with over 12 hours of daylight. When environmental stressors are present, the plant may shift to reproductive growth prematurely as a survival mechanism.
Seeding density also affects bolting rates. Overly dense planting leads to weak, thin seedlings that are more likely to bolt. Conversely, sparse planting results in fewer usable seedlings. Optimal seeding rates vary depending on germination rates, typically ranging from 4–7.5 kg per hectare.
To prevent early bolting, several strategies can be implemented. First, controlling the vernalization stage during winter storage is effective. Seedlings should be stored at 60–65% humidity and -7 to 10°C. Nutritional management is also important—applying appropriate amounts of phosphorus and potassium helps maintain healthy, compact seedlings with a diameter of 0.20–0.50 cm.
Comprehensive measures include proper seed selection, controlled storage conditions, and improved nursery practices. Farmers should avoid buying seedlings from unknown sources and instead cultivate their own to ensure quality. Using techniques like solar greenhouse transplanting or adjusting planting seasons can further reduce bolting risks.
In summary, managing Angelica’s growth to prevent early bolting involves careful seed selection, proper timing, controlled environmental conditions, and thoughtful nursery practices. By understanding and addressing these factors, farmers can improve yields and maintain the quality of this valuable medicinal crop.
Minimally Invasive Thoracolumbar Spinal Fixation System
Minimally Invasive Thoracolumbar Spinal Fixation System,Pedicle Screw Head,Cement Augmented Pedicle Screws,Vertebral Augmentation Screw
Changzhou Ziying Metal Products Co., Ltd , https://www.ziyingmetal.com