Planting and cultivation techniques of Radix Isatidis

Isatis root , as a widely used Chinese medicinal material , its dried roots and leaves have medicinal value. This plant is a biennial herb with a height of approximately 40 cm to 120 cm. Its taproot is long cylindrical in shape, with plump fleshy part and grayish yellow in color. The stem of Isatis root is upright and slightly angular, with multiple branches often branching out at the top and a light powdery frost covering the surface. Let’s learn about the cultivation techniques of Isatis indigotica.

1. Site selection and land preparation

Isatis root, a deep-rooted Chinese medicinal material, has a main root that can reach 40 to 50 cm deep. Therefore, it is suitable for planting in fertile sandy loam with deep soil and good drainage. It is not suitable for growing in low-lying areas or clay with poor drainage.

Before sowing, the land needs to be plowed deeply by 20 to 30 centimeters. Sandy land can be plowed shallowly appropriately, and sufficient base fertilizer should be applied, mainly farmyard manure, with a dosage of 3,000 to 4,000 kilograms per mu. After turning the soil, the soil clods need to be broken up and raked flat to make the bed surface. Flat ridges can be made in the arid northern regions , while high ridges are suitable for making in the south to facilitate drainage. The ridge width is generally 1.5 to 2 meters and the height is about 20 centimeters.

2. Breeding Methods

It is mainly propagated by seeds.

1. Sowing time

The harvested products will be different depending on the time of sowing blue root. Autumn sowing and early spring sowing mainly harvest seeds. The roots of Isatis indigotica in these two periods are not suitable for medicinal use; summer sowing is suitable for the southern region with a long rainy season. Although it reduces diseases and pests, the yield is lower; spring sowing from April to June can harvest both leaves and roots, and has a higher yield. It is the most common sowing method.

2. Sowing method

Draw shallow furrows about 2 cm deep on the bed surface with a row spacing of 20 to 25 cm. After evenly sowing, cover with about 1 cm of soil and compact it slightly. Water appropriately in arid areas. Under suitable temperatures, seedlings will emerge 7 to 10 days after sowing.

3. Field Management

When the seedlings are 7 to 10 cm tall, thin out the seedlings in combination with tillage and weeding, and finally plant them at a spacing of 6 to 8 cm. After transplanting, apply human manure or chemical fertilizers in a timely manner according to the growth of the plants. In water-abundant areas or rainy seasons, deep trenches should be dug to facilitate drainage and avoid root rot. In dry weather, water in the morning and evening, avoiding strong sunlight.

4. Pest and disease control

1. Downy Mildew

It starts to occur frequently from March to April, and is especially severe during the rainy season in spring and summer, mainly harming the leaves. Prevention and control methods include: cleaning the fields and treating diseased plants to reduce pathogens, crop rotation, and spraying 200 to 300 times of 40% ethylene phosphite aluminum solution, once every 7 days, for 2 to 3 times in a row.

2. Sclerotinia

The disease begins in April and becomes more severe during the rainy and hot months from May to June. It is transmitted from the soil, with the base leaves becoming infected first and then spreading upward to damage the stems, stem leaves and fruits. Prevention and control methods include: water-land rotation or rotation with gramineous crops, increasing the application of phosphorus and potassium fertilizers, and applying a lime-sulfur mixture to the base of the plants.

3. Pieris rapae

Its larvae are commonly known as cabbage loopers, and they start to damage leaves from May, especially from early to late June. They can be controlled by spraying biological pesticide BT emulsion, 200 to 250 grams per 1,000 square meters or 800 times diluted 90% dichlorodiphenyltrichloroethane.

5. Harvesting and Processing

Before harvesting the roots of spring-sown isatis root, the leaves can be harvested 2 to 3 times. The first time is in mid-June when the seedlings are about 20 cm tall, leaving 2 to 3 cm of stubble to facilitate the growth of new leaves. The second time is in late August during the hot season, and it is not suitable to harvest in order to avoid causing large-scale death. The harvested leaves can be dried to become medicinal isatis indigotica. The best leaves are those that are large, less broken, clean, dark green in color, and have no musty smell.

Isatis root should be dug on a sunny day before winter, and be sure to dig deep to avoid breaking the roots. After digging up the soil, remove the dirt, stems and leaves, spread it out to dry until it is 70% to 80% dry, tie it into small bundles, and continue drying it until it is completely dry. The best roots are those that are long, straight, thick, solid and powdery.

In short, as a bulk medicinal material, the market demand for Isatis root is still very stable, but we must also pay attention to whether it is suitable for cultivation in the local area.