Detailed Explanation of Key Field Management Techniques for Angelica sinensis

1. Thinning and final thinning: When the seedlings are 3 cm tall, carry out the first thinning, and after another half a month carry out the second thinning. When the seedlings are 10 cm tall, carry out final thinning. For hole sowing, keep 2-3 strong seedlings per hole.

2. Cultivation and weeding: Angelica sinensis grows slowly at the early stage of emergence, while weeds grow rapidly, so weeding should be done in a timely manner. From emergence to row closure, weeding should be done 3-4 times in stages. The first weeding is carried out when the seedlings are about 5 cm tall, the second after final thinning, and the third when the seedlings are 20-25 cm tall, that is, before row closure. Loosen the soil while hoeing to prevent soil compaction, improve aeration, moisture and temperature conditions, and promote root development. Hoeing should follow the principle of "deep in the middle, shallow at both ends", that is, deep hoeing is not suitable when the seedlings are young and small or after the Beginning of Autumn. This is because after the Beginning of Autumn the root system of Angelica sinensis is mostly enlarged and rich in sugar, and once damaged it easily causes root rot. At this time, if there are weeds, they should be pulled out promptly.

3. Topdressing: Angelica sinensis has a relatively high fertilizer requirement throughout its life. In addition to applying sufficient base fertilizer, it should also be topdressed in a timely manner. The suitable time for topdressing is the vigorous leaf growth period in late June and the root growth period in August, which are the two peak periods of fertilizer demand. The amount of topdressing should be greater during the root growth period than during the leaf growth period and the greening period. Usually potassium dihydrogen phosphate, diammonium phosphate and nitrogen-phosphorus-potassium compound fertilizer are used for topdressing.

4. Drainage and irrigation: In the early growth stage, except for appropriate watering during drought, watering is generally controlled. If there is too much rain, ditches should be dredged promptly for drainage, especially in the late growth stage, when the field must not accumulate water, otherwise it easily causes root rot.

5. Earthing up: When Angelica sinensis grows to the middle and late stages (after August), the root system begins to develop and grows rapidly. Earthing up at this time can promote the development of the main root and help increase yield and quality. Earthing up can be carried out together with soil loosening.