A Detailed Guide to Corydalis yanhusuo Cultivation Techniques: Teaching You to Grow Corydalis yanhusuo Well

Corydalis yanhusuo, also known as Xuanhu or Yanhusuo, is a perennial herbaceous medicinal plant whose tubers are used as medicine, and it is one of the commonly used traditional Chinese medicinal materials. So what are the cultivation techniques for Corydalis yanhusuo?

Cultivation Techniques for Corydalis yanhusuo

The cultivation techniques for Corydalis yanhusuo can be summarized in four phrases: “a little shallower, a little sparser, a little warmer, a little wetter”. By a little shallower, the planting (soil covering) depth should preferably be 2 cun; by a little sparser, the sowing density should preferably be 2.5 cun square or with a row and plant spacing of 2×3 cun; by a little warmer, insulation is needed to survive the winter; by a little wetter, the bed surface should be kept moist and must not be too dry.

1. Land selection

When planting Corydalis yanhusuo, choose fertile plots (fields) with deep soil layers, good irrigation and drainage, and relatively high soil organic matter content. Sandy loam is preferable, with sandy clay, half-sand half-clay fields, and alluvial soil being the best. Dead yellow mud, white clay soil, and gravelly soil are all unsuitable for planting. The soil's physical and chemical properties should preferably be neutral or slightly acidic, usually with a pH of around 5.6-7.5.

The root system of Corydalis yanhusuo is mainly distributed in the topsoil at a depth of about 1-3 cun. The looser the soil, the more developed the root system, which is conducive to the swelling of stem nodes and the absorption of nutrients; the daughter tubers of Corydalis yanhusuo are large, numerous, and high-yielding. Compacted soil is not conducive to the growth and spreading of stems and branches, resulting in small stem nodes and low yields. If the soil is too alkaline, it easily causes stunted seedlings, slow growth, and shrinking of the fibrous roots (stem branches). Soil that is too sandy has poor water and fertilizer retention, easily leading to premature aging of growth; and because sandy soil absorbs heat too strongly, with large day-night temperature differences, the ground temperature exceeds the environment required by the crop, inhibiting growth.

2. Land preparation

After selecting the field for planting Corydalis yanhusuo, first carry out fine tillage. Plow three times and harrow three times to work the topsoil into a loose and fine loam; this is the foundation for achieving increased yields of Corydalis yanhusuo. If there are many large clods of soil in the Corydalis yanhusuo field, it will both affect seedling emergence and hinder root growth, seriously reducing the yield of the following year. When preparing the Corydalis yanhusuo field, apply sufficient base fertilizer at the same time, because Corydalis yanhusuo has shallow roots and likes fertilizer, and its growing season is short, so applying sufficient base fertilizer is the key to increasing yield. According to the analysis of results from extensive high-yield experience, applying 3000 jin of decomposed pig and cattle pen manure, 100 jin of oil cake fertilizer, and 100 jin of phosphate fertilizer per mu can achieve a relatively good yield. If oil cake fertilizer is applied excessively or undecomposed fertilizer is placed in direct contact with the seed tubers, it will cause seedling burn; although the seed tubers do not change color or rot, the buds stop growing after sprouting 1-2 cm. If too much nitrogen fertilizer is applied, it will cause excessive vegetative growth of stems and leaves, and they will collapse in patches when heavy rain occurs, and it will also create favorable conditions for the parasitic reproduction of downy mildew spores, causing large-scale death after infection and resulting in reduced yield. Therefore, when applying oil cake fertilizer, fermenting it in advance is beneficial for the full absorption by the root system of Corydalis yanhusuo.

3. Bed making

After the plot is prepared, make the beds immediately. Usually, making beds transversely is preferable, as it facilitates drainage and irrigation; at the same time, shorter bed surfaces are easier to level, which can improve land utilization. Reasonable bed making on one mu of land gives a usable area of about eight fen. Generally, the bed width is 4 jin, the ditch width is 7 cun-1 chi, and the ditch depth is 5-7 cun. The specific bed making is as shown in the diagram: