Detailed Explanation of the Forcing Cultivation Techniques for Chicory (Softening Type)
After the root plants are harvested, it is best to subject them to a certain period of low-temperature treatment before forcing cultivation. The duration of low-temperature treatment varies by variety: early-maturing varieties can be treated for a shorter time, while late-maturing varieties should be treated for a longer time, so that tighter chicons can be formed. The methods of forcing cultivation are quite flexible and can be broadly divided into soil culture and water culture. Soil culture is a relatively traditional cultivation method and can be carried out by digging trenches in the ground inside a plastic tunnel or greenhouse. Its characteristics are low cost and simple operation, but the biggest drawback is that the chicons formed are not clean. Water culture, on the other hand, requires specialized facilities and equipment, which increases costs, but the environmental conditions are easier to control artificially and excellent cultivation conditions can be created. Water culture is further divided into water solution culture and substrate culture. The substrate generally used is peat (peat has good air permeability, strong water retention, and few contaminating microorganisms).
Soil culture is generally carried out on the ground. In the Beijing area, it can be done in plastic tunnels and greenhouses with added heating cables. First, dig a trench 1.5 m wide and 25 cm deep; the length depends on the site. Lay heating cables at the bottom and cover with 3 cm of soil. After slightly sorting the root plants (pull off rotten leaves, cut the roots to 14-18 cm in length), they can be placed one next to another in the trench. After a bed is laid out, scatter 6-8 cm of soil on top. Wait until the soil above fills into the gaps between the roots, stop watering, then cover with another 15 cm of soil, leaving more than 20 cm of space above. Cover with black film or use other light-blocking materials. When the temperature is maintained at around 18°C, the chicons can be harvested in about 20 days. Note that used trenches and soil cannot be used again.
Water culture can be carried out indoors or in a greenhouse. In France, growers use wooden troughs with 4 legs specially designed for forcing, and carry out vertical cultivation in darkness with mechanized operation, achieving very high production efficiency. For small-scale cultivation, it can be done in containers 40-50 cm high, or in troughs 30 cm high in a greenhouse or room. When using water solution culture, be careful to wash the roots clean and first pull off rotten leaves and outer leaves. The water level should be below 1/2 of the roots and above 1/3. Circulating water and clean water are best. When using peat as the substrate for cultivation, first spread moistened peat, then place the roots. The peat should reach above 2/3 of the roots. After filling, water once. In water culture, no substrate is covered over the root plants, so it is relatively clean.
Whether using soil culture or substrate culture, watering only at the beginning is enough to meet the requirements until harvest. The forcing cultivation of chicory can be carried out according to local conditions. As long as the moisture, temperature, and darkness conditions required for chicory growth are met, chicory chicons can be produced; the methods merely differ in their advantages and disadvantages.
After the main chicon of chicory is harvested, lateral buds can also be produced. If the roots with the shortened stem cut off undergo tissue callusing, many fine small buds can also grow, but much more slowly. The small buds from the second harvest are also quite distinctive and are called "monk's beard" in the French market. The yield of chicory chicons is equivalent to about 7,500-15,000 kg per hectare in the field, and the output value can reach more than 150,000 yuan.