Key Cultivation Techniques for the Chinese Medicinal Herb Saposhnikovia divaricata
1. Site Selection and Land Preparation
Saposhnikovia divaricatais a deep-rooted plant, with a main root that can reach 50-60 cm in length. It should be planted on sandy loam soil on high, dry terrain with good drainage; when grown on clay soil, the roots of Saposhnikovia divaricata are extremely short, heavily branched, and poor in quality. During land preparation, apply sufficient base fertilizer, using 3000-4000 kg of barnyard manure and 15-20 kg of superphosphate per mu, then deep plow and harrow thoroughly. In the north, make flat beds 1.3-1.7 m wide.
2. Propagation is mainly by seed, though root division propagation can also be used
(1) Seed propagation Sowing can be done in both spring and autumn. For spring sowing, the Yangtze River basin sows from late March to mid-April, while North China sows from early to mid-April; for autumn sowing, the Yangtze River basin sows from September to October, while North China sows before the ground freezes, with seedlings emerging the following spring. For spring sowing, the seeds need to be soaked in warm water for 1 day to allow full water absorption and promote germination. In the prepared beds, open furrows 25 cm × 8 cm apart for drilling, with a furrow depth of 2 cm, cover with 2—3 cm of soil, sow the seeds evenly into the furrows, cover with soil and level it off, press down lightly, cover with grass and water, and keep the soil moist. Seedlings will emerge 20-25 days after sowing. Use 2 kg of seed per mu.
(2) Root division propagation At harvest time or in early spring, take root sections thicker than 0.7 cm and cut them into small pieces 3 cm long to use as seed material. Plant at a spacing of 15 cm × 35 cm with a hole depth of 4—5 cm, placing 1 root section per hole, inserting it upright, then covering with 3-5 cm of soil after planting. Use about 50 kg per mu.
3. Field Management
(1) Thinning When seedlings are 5 cm tall, thin them to a spacing of 7 cm; when seedlings are 10-13 cm tall, thin to a final spacing of 13-16 cm.
(2) Weeding and Earthing Up Before June, weed several times to keep the field clean. When the plants close canopy, first remove the old leaves, then earth up around the roots to prevent lodging; in winter, along with clearing the field, earth up again to help the roots survive the winter.
(3) Topdressing Apply topdressing once each in early June and late August every year, using human manure, superphosphate or compost, applied in furrows between the rows.
(4) Bolting Removal For plants over 2 years old, except those kept for seed production, the bolting stems should be removed promptly.
(5) Drainage and Irrigation From after sowing or planting until seedling emergence, the soil should be kept moist. Saposhnikovia divaricata is highly drought-tolerant and mostly does not need irrigation; during the rainy season, take care to drain promptly to prevent waterlogging and root rot.
4. Pest and Disease Control
(1) Powdery mildew It damages plants in summer and autumn, affecting the leaves. Control methods: ① Apply phosphorus and potassium fertilizers and ensure good ventilation and light penetration; ② When the disease occurs, spray with a 50% Thiophanate solution at 800-1000 times dilution.
(2) Yellow-winged fennel borer It occurs at the bud and flowering stages, damaging flower buds and fruits. Control methods: In the morning or evening, spray with 90% Trichlorfon at 800 times dilution or BT emulsion at 300 times dilution.
(3) Yellow swallowtail butterfly It begins damaging in May, with larvae biting and eating leaves and flower buds. Control methods: ① Handpick and kill; ② At the young larval stage, spray with 90% Trichlorfon at 800 times dilution or 80% Dichlorvos emulsifiable concentrate at 1000 times dilution.