Detailed Explanation of the Key Points of Angelica sinensis Cultivation and Management Techniques

For transplanted seedlings, loosen the soil and weed 3-4 times in one year, with the first time when the seedlings are 3-5 cm tall. Apply topdressing after intertillage and weeding; the first time apply 1500-2500 kg of thin human and livestock manure water per 667 sq m; the second and third times apply 2500-3000 kg of decomposed stable manure, compost or burnt soil ash per 667 sq m. Promptly pull out bolting seedlings, and water during droughts, but watering is prohibited in the later stage to avoid root rot.

Premature bolting problem: The key problem in Angelica sinensis production is early bolting (in the year of transplanting). Generally, the early bolting rate is 30%, and in severe cases it can reach more than 50%. The roots of bolted Angelica sinensis are highly woody, faint in odor, lacking oiliness, poor in quality, and cannot be used as medicine. The reason for early bolting of Angelica sinensis is that in individual development, the transition from non-bolting to bolting requires going through two developmental stages: the vernalization stage and the photoperiod stage. The former requires a low temperature of 0-5°C, while the latter requires a long daylength of more than 12 h. Under natural conditions, the low temperature comes from winter, and the required long daylength occurs around summer. For annual Angelica sinensis, the long daylength can be passed in the summer of that year; it does not bolt because it has not experienced winter low temperature. However, not all planting stock that has undergone winter storage can pass through the vernalization process and bolt and flower. Angelica sinensis planting stock must also have sufficient sugar content in itself to pass through the vernalization process, so large planting stock tends to bolt, while small planting stock is less likely to bolt.

In order to reduce early bolting of Angelica sinensis, the size of the planting stock is controlled by improving seedling-raising techniques, thereby achieving the purpose of controlling bolting. Some technical measures can be adopted:

First, choose a seedling-raising site preferably on a semi-shady slope in a high-cold mountainous area with medium soil fertility; or delay the sowing and seedling-raising period, keeping the seedling age within 70 days; make the seedling root diameter about 3.5 mm, etc. The method of direct sowing after the Start of Autumn can also be used, resulting in a very low early bolting rate.

Second, when transplanting in the second year, it is best to plant in land with deep, loose, fertile soil and good drainage. After the seedlings recover, strengthen fertilizer and water management so that the seedlings grow robustly and the roots obtain a large amount of assimilates, thereby increasing the yield and quality of the medicinal part.

Third, cold storage of seedlings: after lifting the seedlings, store the planting stock at a low temperature of about -10°C until planting in the following spring. Because the seedlings cannot obtain the necessary conditions for vernalization, the stage change cannot be achieved, and the bolting rate is reduced.