Cultivation Methods and Key Management Techniques for Lithospermum
1. Climate and Soil
Lithospermum is cold-resistant, intolerant of high temperatures, and afraid of waterlogging. Calcareous loam, sandy loam, and clay loam soils are best.
2. Land Preparation
After deeply plowing and raking the soil level, open small furrows with a spacing of 20-30 cm. Apply manure or green manure in the furrows.
3. Planting
Seedling method: Sow in early April. First water the seedbed, and after the water has seeped in, scatter the seeds, then cover with about 1 cm of soil. Keep it constantly moist; seedlings emerge in 15-22 days. When the seedlings are 6-10 cm tall, transplant them to the field with a row spacing of 30 cm and a plant spacing of 10-15 cm, press lightly, and water.
Direct sowing method: Sow around Qingming (early April), in rows, opening shallow furrows with a row spacing of 30 cm, sow the seeds evenly, and press the soil down after sowing. When the seedlings are about 6 cm tall, thin them to a plant spacing of 10-15 cm.
4. Field Management
During the seedling stage, protect against high temperatures and direct sunlight, and pay attention to watering, weeding, and loosening the soil. Drain promptly during the rainy season. When the seedlings are 20-25 cm tall, apply 20-25 jin of superphosphate per mu, then cover with soil and water.
Land Preparation and Fertilization
It is advisable to choose high-lying, well-drained, loose and fertile sandy loam or loam for planting. Before sowing, apply 75,000 kg of farmyard manure per hectare, deeply plow more than 30 cm, break the soil up fine and rake it level, and make beds 100 cm wide, ready for sowing.
Propagation Methods
Propagate by seed, divided into autumn sowing and spring sowing. Autumn sowing runs from after the seeds are harvested until the ground freezes in early November; seeds sown in autumn begin to germinate in early April of the second year, with full emergence from late April to early May. Spring sowing is carried out from March to early April, with emergence from late April to early May. Seeds for spring sowing must undergo low-temperature treatment to allow the embryo to develop and mature; if the seeds are sown dry, they will not emerge that year. Sowing methods are divided into two types: drilling and broadcasting.
Seed treatment: From late October to early November, mix the seeds evenly with moist sand at a ratio of 1:3, then store them in a pit. Dig a pit 45 cm deep and 30 cm both long and wide on a sunny slope, place a small amount of twigs at the bottom of the pit, spread a layer of leaves on top, put the seeds in, and cover with 10 cm of soil. During the sand storage of the seeds, take care to prevent damage from rats. Around Qingming of the following year, when most of the seeds have sprouted, sow them.
Drilling: Open shallow furrows 3 cm deep with a row spacing of 15-20 cm, sow the seeds evenly, cover with 3 cm of soil after sowing, and press down after sowing. The application rate is 22.5-30 kg per hectare.
Broadcasting: Scatter the seeds evenly over the bed surface, cover with 2-3 cm of soil, and after sowing make the seeds contact the soil and press lightly. The sowing rate is 30 kg per hectare.
When sown in spring after seed treatment, with sufficient temperature and moisture, emergence begins in about 10 days.
Field Management
(1) Cultivation and Weeding
Carry out loosening of the soil and weeding in good time to prevent weeds from overpowering the seedlings.
(2) Replanting and Final Thinning
During the seedling stage, check and fill in gaps promptly; if too dense, thin appropriately, and if gaps are found, replant promptly on rainy days or in the evening, then water and preserve soil moisture. When the seedlings are 10 cm tall, thin to a final spacing of 15 cm x 10 cm between rows and plants.
(3) Topdressing
After final thinning, apply 150 kg of urea per hectare; after flowering, apply 225 kg of superphosphate per hectare. Apply on rainy days or water after application.
(4) Drainage and Irrigation
Lithospermum is most afraid of waterlogging; pay attention to drainage during the rainy season to avoid root rot. If drought is severe, water appropriately.
Pest and Disease Control
(1) Root Rot
Occurs in hot or rainy seasons. The roots rot and the aboveground stems and leaves wither.
Control methods: 1) Drain promptly after rain. 2) Remove diseased plants and burn them, and disinfect the diseased holes with lime powder. 3) Irrigate the diseased holes with 1% ferrous sulfate for disinfection.
2) Leaf Spot
Damages the leaves, forming irregular lesions on them.
Control methods: 1) Pull out diseased plants promptly. 2) Use a 1:1:100 Bordeaux mixture for control.
(3) The insect pests of Lithospermum include white grubs, mole crickets, cutworms, and weevils, which can be captured manually or poisoned with bait.