Summer sowing of Isatis indigotica has many advantages, worth growers' choice

Isatis indigotica (woad) is a bulk medicinal herb with good sales on the current market. It can be sown in spring, autumn, and also in summer. However, judging from our trial demonstrations over the past two years, summer-sown Isatis indigotica is much welcomed by herb growers for its advantages of a short growth period, excellent quality, high yield, no effect on subsequent crops, and relatively high returns. The average yield per mu is 450 kg of Isatis root and 120 kg of Daqingye (woad leaves), with an income of about 1500 yuan per mu. Its cultivation techniques are briefly introduced as follows:

1. Land preparation and fertilization: After summer-harvested crops such as wheat and potato are harvested, deep-plow and prepare the land in time. For single-ridge preparation, apply 2000 kg of organic fertilizer and 50 kg of superphosphate per mu as base fertilizer. Then level and harrow fine to make high beds 1.3 m wide, leaving drainage ditches around.

2. Sowing: Summer sowing is generally from late May to early June, preferably by drilling. On the prepared bed surface, open shallow furrows at a row spacing of about 20 cm and a furrow depth of 2-3 cm, then sow the seeds evenly into the furrows at about 1.5 kg per mu. After sowing, cover with 2 cm of fine soil and keep the soil moist; seedlings emerge in 6-7 days.

3. Field management: When the seedlings are 7-8 cm high, thin them; when they are 10-12 cm high, set the plants at a spacing of about 12 cm. After setting the plants, carry out the first cultivating and weeding; thereafter weed once about every 26 days, keeping the field free of weeds. Stop cultivating and weeding after the rows close, and apply 1 topdressing of human and livestock manure water at 1500 kg per mu together with weeding. If drought occurs after summer sowing, water promptly; if there is too much rain, clear the ditches and drain promptly to prevent waterlogging in the field.

4. Harvesting and processing: In late September, harvest Daqingye (woad leaves) in one go, cutting from the base of the plant at 2 cm above the ground. After cutting back, sun-dry to 70-80% dry, tie into small bundles, continue sun-drying until fully dry, and in rainy weather dry them promptly over a heated bed. In mid-to-late October, dig up the underground roots. When digging, try to keep the roots intact and avoid damaging or breaking them. After transporting back, remove soil and the rhizome neck, wash clean, sun-dry to 70-80% dry, tie into small bundles, then sun-dry until fully dry. If continuous rain occurs, dry them promptly over a heated bed.