Detailed Guide to Three-Dimensional Intercropping Techniques for Fritillaria cirrhosa and Ligusticum sinense

Intercropping and Three-Dimensional Cultivation Techniques for Fritillaria cirrhosa and Ligusticum sinense

1. Biological Characteristics of Fritillaria cirrhosa and Ligusticum sinense

Fritillaria cirrhosa D. Don is a plant of the genus Fritillaria in the Liliaceae family, with characteristics of cold tolerance, moisture preference, intolerance of high temperatures, and avoidance of strong light. It cannot survive in areas with low altitude, high temperatures, and intense direct light. Wild Fritillaria cirrhosa often grows in southwestern China and on the Qinghai-Tibet Plateau at 2,700-4,500 m on sunny grassy slopes or shrubby grassy slopes with relatively low temperatures and relatively moist soil. The growth period is 90-120 d.

Ligusticum sinense Oliv. is a plant of the genus Ligusticum in the Apiaceae family. It prefers cool, humid climates. Wild plants are mostly distributed at altitudes of 1,500-3,500 m on mountain slopes, forest edges, and semi-shaded, semi-sunny areas with good drainage. It is cold-tolerant, intolerant of high temperatures, and afraid of waterlogging. It is not strict about soil requirements, but loose, fertile, well-drained sandy loam is best. The growth period is from the end of March to early November.

2. Advantages of Intercropping

First, both Fritillaria cirrhosa and Ligusticum sinense are perennial herbaceous plants, and both prefer humid climates. The Fritillaria plant height is about 15-25 cm, the plant is relatively slender, and it grows only from early April to July; the Ligusticum sinense plant height is about 20-60 cm, with many branches on the stem, luxuriant leaves, and a long growth period from the end of March to November. When the two are intercropped, Ligusticum sinense can provide shade throughout the entire growth period of Fritillaria, which not only satisfies the Fritillaria's preference for scattered light, but also saves the shading cost required for cultivating Fritillaria. Second, Fritillaria is a fibrous-rooted plant, with roots that do not go deep into the soil; the root system is mainly distributed in the shallow surface layer of the soil and can only absorb water and nutrients from the upper soil. Ligusticum sinense is a deep-rooted plant with a powerful root system that penetrates deeply into the soil and can absorb water and nutrients from deeper soil layers. Intercropping these two medicinal plants can make full use of soil fertility, allow soil nutrients to be fully utilized, and is also an important cultivation measure for effectively using land and increasing economic income.

3. Cultivation Techniques

3.1 Land Selection and Land Preparation

According to the biological characteristics of Fritillaria cirrhosa and Ligusticum sinense, areas should be selected at an altitude of about 2,000-2,600 m, sheltered from the wind, on semi-shaded, semi-sunny slopes, with soil requiring deep soil layers, loose texture, good drainage, and rich humus. After selecting the plot, plow 30 cm before sowing, and apply 2,000 kg/667 sq m of barnyard manure or farmyard manure in combination with plowing. Break up the soil finely and rake it level, and make flat beds about 1.0 m wide and 10 cm high, with 30-40 cm between beds. Dig drainage ditches around the perimeter.

3.2 Sowing

3.2.1 Sowing of Ligusticum sinense

Ligusticum sinense can be established by two methods: direct seed sowing or seedling transplanting. Direct seed sowing can be done in spring or winter; spring sowing is in early and mid-April, and winter sowing is before the soil freezes. When sowing, open a furrow about 20 cm from the bed edge, with a furrow depth of 2 cm, evenly scatter plump, well-filled seeds into the furrow, then cover with soil and water. For seedling transplanting, spring planting or autumn planting can be used. When transplanting, dig holes about 15 cm from the bed edge, with a hole depth of about 10 cm, and a plant spacing of about 20-25 cm. Plant 1-2 plants per hole, then cover with soil, firm it, and water. For spring planting, cover with soil to 2-3 cm above the rhizome; for autumn planting, cover slightly deeper. Spring-planted plants generally emerge in 10-15 d, while autumn-planted plants sprout in the following spring.

3.2.2 Sowing of Fritillaria

For direct-seeded Ligusticum sinense, Fritillaria is intercropped in the second year; for transplanted seedlings, it is intercropped in the same year. In intercropping cultivation, Fritillaria is planted on the center line of the bed surface. Generally, small bulbs grown for 1-2 a are used as planting material, and Fritillaria seeds can also be directly sown. When bulbs are used as planting material, plant the small bulbs in the Ligusticum sinense bed in August-September, planting by opening furrows or digging small holes, with a plant spacing of about 5-8 cm, cover with 5-6 cm of soil, press firm and level. For seed sowing, in early April when the soil thaws, drill the Fritillaria seeds that have undergone after-ripening treatment in rows in the bed, cover with a layer of uniformly mixed humus fertilizer soil about 1 cm thick, and water to maintain moisture.

3.3 Field Management

3.3.1 Thinning and Final Singling of Seedlings

For direct-seeded Ligusticum sinense, when the seedlings are 3-4 cm tall, appropriate thinning and replanting should be carried out; when the seedlings are 7-8 cm tall, final singling should be done, with a plant spacing of 20 cm. After the Fritillaria sown from seed emerges, thinning is not needed. For those sown in the current year, small bulbs can be transplanted in the following spring to fill gaps.

3.3.2 Weeding

When Ligusticum sinense is intercropped with Fritillaria, weeding is needed 2-3 times per year. In the first year of intercropping, before sowing Fritillaria, weed once in combination with sowing; after sowing, weed once more when the Fritillaria seedlings are 3-5 cm tall; and weed one last time after the Fritillaria tops die back. In the second and third years, when the Ligusticum sinense plants are in a period of vigorous growth, weed once in early spring when the Ligusticum sinense seedlings have just emerged, and weed once in June-July when harvesting young stems and leaves. When weeding, manual weeding must be carried out around the Fritillaria plants so as not to damage the Fritillaria bulbs; any small Fritillaria brought out must be immediately replanted into the soil.

3.3.3 Fertilization

Intercropped Ligusticum sinense and Fritillaria have a high fertilizer requirement. When Ligusticum sinense has just turned green, open a furrow between the Fritillaria and Ligusticum sinense and apply 10-15 kg of urea in combination with watering; after the Ligusticum sinense tops die back in November, apply 2,500-3,000 kg of humus soil or farmyard manure per 667 sq m, and cover with 3 cm of soil. This both increases soil fertility and helps the Fritillaria overwinter.

3.3.4 Shade Density Management

Fritillaria needs shade throughout its entire growth period, and in intercropping cultivation the shade density must be well controlled. In the first year, the Fritillaria seedlings are weak and the Ligusticum sinense plants do not grow vigorously, so the shade density does not need to be adjusted. In the second and third years, the Fritillaria seedlings grow strongly and have a high light requirement, while the Ligusticum sinense branches and leaves are luxuriant. In June-July, the inner Ligusticum sinense stems and leaves need to be picked for consumption, but they must not all be removed at once; adjust the shade density to 40%-50%, picking once every 15-20 d.

3.3.5 Overwintering Management

Each year in November, when the Ligusticum sinense plants turn yellow and the tops die back, the Ligusticum sinense plants should be cut down and the field cleaned. Especially in the third year, when the Ligusticum sinense plants have grown to 60-70 cm tall, cut them down immediately after harvesting the seeds, so as to benefit the growth of Ligusticum sinense the following year.

3.3.6 Water Management

Both Ligusticum sinense and Fritillaria prefer moisture and fear waterlogging. During continuous drought, water promptly to keep the soil moist, especially in the first and second years of intercropping, when the Fritillaria seedlings are weak and have relatively poor drought resistance. After prolonged rain or heavy rain, promptly clear the drainage ditches to prevent water accumulation and root rot.

3.3.7 Removing Flower Buds

Ligusticum sinense flowers a small amount in the second year, and the flowering branches should be removed. It flowers abundantly in the third year; if the seeds are not being harvested for use as a seed source, the flowering branches should also be removed to benefit the growth of the underground root system.

4. Pest and Disease Control

Ligusticum sinense is not prone to pests and diseases; during the rainy season, pay attention to regulating soil moisture to prevent root rot. Fritillaria seedlings are prone to damping-off disease in the rainy summer season. When the disease occurs, pay attention to drainage and adjust the shade level, and Bordeaux mixture can be sprayed. In addition, Fritillaria bulbs are prone to turning yellow and rotting in May-June. When the disease occurs, pull out the diseased plants, reduce soil moisture, and irrigate with 50% carbendazim 500-fold solution or 5% lime water.

5. Harvesting

5.1 Harvesting Stems and Leaves of Ligusticum sinense

Ligusticum sinense stems and leaves can be harvested in appropriate amounts for consumption in the second year, and enter the peak harvest period in the third year. They can be harvested when the plant height is 30-40 cm. Harvesting is flexibly determined according to the tenderness of the stems. The stems and leaves of each plant cannot all be harvested at once; the outer side of the bed can be harvested heavily, while the inner side should be harvested in appropriate amounts according to the light requirement of Fritillaria. The harvest period is from May to early and mid-August.

5.2 Seed Harvesting

Ligusticum sinense flowers abundantly in the third year, and 6-10 kg of seeds can be harvested per 667 sq m. Ligusticum sinense has a relatively long flowering period, and seed maturity is uneven. It can be harvested when the fruit branches turn brown. Do not harvest too late, otherwise the seeds are prone to falling. In intercropping cultivation, Fritillaria sown from seed is not harvested for seed; those using bulbs as planting material set fruit in the third year and can be harvested for seed. When the fruit shells turn yellow-brown or brown, cut off the fruits, remove the fruit shells while fresh, shake out the seeds, and immediately carry out after-ripening treatment.

5.3 Digging of Medicinal Parts

After three years of intercropping cultivation, the roots or bulbs of both plants can be dug. Fritillaria is harvested after the tops die back in June-July, choosing a sunny day when the soil is slightly dry. Gently insert a small hoe into the soil and pry upward, shake off the soil, and the bulbs will be exposed. Be careful not to damage the bulbs. After harvesting, grade promptly; small bulbs are sold after primary processing, and large bulbs are kept as planting material for seed production. After harvesting Fritillaria, immediately cover with soil to maintain soil moisture and nutrients and sustain the later growth of Ligusticum sinense. Ligusticum sinense is dug in the autumn of the same year as the Fritillaria harvest, after the aboveground parts wither. Cut off the withered aboveground branches, dig deeply with a large hoe, and dig out the rhizomes. Sun-dry the large rhizomes for sale, and keep the slender rhizomes as planting material.