What are the key points of high-yield management techniques for Angelica dahurica

1. Thinning and final thinning:

Angelica dahurica seedlings grow slowly, and in the year of sowing, thinning is generally not carried out. After the seedlings turn green in early spring of the second year, when the seedlings are about 5-7 cm tall, the first thinning is carried out, removing the overly dense and weak seedlings. For drilling, leave one plant every about 5 cm; for hole sowing, leave 5-8 plants per hole; for the second thinning, leave one plant every about 10 cm or leave 3-5 plants per hole. Around Qingming, when the seedlings are about 15 cm tall, final thinning is carried out, with a plant spacing of 13-15 cm or leaving 3 plants per hole, staggered in a triangle to facilitate ventilation and light penetration. During final thinning, the overly vigorous large seedlings with greenish-white leaf stalks should be pulled out to prevent premature bolting and flowering.

2. Intertillage and weeding:

It is best to carry this out together with thinning and final thinning. When the leaves gradually grow larger and the bed surface is closed and shaded, there is no need to weed anymore.

3. Topdressing:

Angelica dahurica is a relatively fertilizer-tolerant crop, but generally before spring it should be given little or no fertilizer to prevent excessive growth during the seedling stage and premature bolting and flowering. After spring, vegetative growth begins to flourish, and topdressing can be applied 3-4 times. The first and second times are both carried out after thinning and intertillage, and the third and fourth times are carried out after final thinning and before closing the rows. Fertilization should preferably be done on sunny days; it is not suitable to fertilize on the day when rain has just cleared or after intertillage and weeding. Fertilizer types can include human feces and urine, decomposed cake fertilizer, barnyard manure, urea, etc. For the first fertilization, the fertilizer should be thin and small in amount, such as applying 10 loads of diluted human and livestock manure per mu, and afterward it can gradually be made thicker and increased, such as 30-40 loads. The application before closing the rows can be combined with phosphorus and potassium fertilizer, such as 20-25 kg of superphosphate, to promote thick roots. It has been reported that in the topdressing before closing the rows, applying 25 kg of calcium magnesium phosphate fertilizer and 5 kg of potassium chloride, followed immediately by hilling, can prevent lodging and promote growth. The number of topdressings and the amount each time can also be determined according to the growth of the plants. If the leaves are light green and not very vigorous when the rows are about to close, another topdressing can be applied; or if the leaf color is dark green and growth is vigorous at this time, it may not be applied.

4. Drainage and irrigation

Angelica dahurica likes water, but fears waterlogging. After sowing, if the soil is dry, it should be watered immediately. Afterward, if there is no rainy weather, it should be watered once every few days to keep the bed surface moist before the seedlings emerge, as this is beneficial for emergence; during the seedling stage, the soil should also be kept moist to prevent yellow leaves and the production of many lateral roots; before the seedlings overwinter, they should be watered thoroughly once. Henan has the experience that "wet freezing is best, dry freezing does not easily survive," and Hebei has the experience that "Angelica dahurica in winter only dies from dryness, not from freezing." After spring of the following year, irrigation can be applied at appropriate times together with topdressing, especially during the dog days when sufficient moisture should be maintained. If there is a rainy season and water accumulates in the field, ditches should be opened in time for drainage to prevent root rot and disease occurrence from waterlogging.

5. Pulling out bolting seedlings

In May of the second year after sowing, some plants will bolt and flower. Their roots cannot be used as medicine, and the seeds they produce also cannot be used as seed, because the next generation will bolt prematurely. Therefore, in order to reduce the consumption of nutrients in the field, bolting plants should be pulled out in time when found.