Detailed Explanation of the Key Cultivation Techniques for Rutabaga

Rutabaga, also known as Swedish turnip, yellow turnip, and gray radish, is a biennial herbaceous plant of the genus Brassica in the family Brassicaceae. Its cultivation history in China is very short, but it has the characteristics of wide adaptability, strong stress resistance, easy cultivation, high yield, and dual use as both grain and vegetable. It is therefore cultivated in Hebei, Henan, Shandong, Inner Mongolia, Shanghai, Jiangsu, Fujian, Yunnan, Guizhou and other places in China. Rutabaga is rich in nutrients, suitable for boiling, and can substitute for grain. For vegetable use, it can be stir-fried or salted, and it is also a very good feed.
　　
I. Types and Varieties
1. Shanghai Rutabaga
The leaf cluster is semi-erect. The leaves are long obovate, dark green in color, covered with a white powdery bloom on the surface, deeply lobed, with 6 to 8 pairs of lateral lobes. The fleshy root is nearly spherical; the part emerging from the soil has purple skin, the part in the soil is light yellow, and the flesh is white-green. The growing period is about 100 days, and a single root weighs 800 to 1000 g. The flesh is relatively fine and of medium quality. It stores well and can be stir-fried or pickled. Locally, it is sown from late July to early August, transplanted in late August, and harvested in December. It is relatively commonly cultivated in Shanghai, Zhejiang, Fujian, Jiangsu, Shandong and other provinces and municipalities.
2. Bashang Goutou Manjing
It is mainly distributed in the Bashang area of Hebei. The leaves are large, numerous, deep green in color, with abundant waxy bloom, close to the cabbage type, and the plant is relatively large. The fleshy root is short spindle-shaped, with many thick coarse fibrous roots, resembling a dog's head, hence the name. The skin color comes in three types: purple skin, yellow skin, and white skin, with the purple-skinned type being more commonly cultivated. It is late-maturing, with a growing period of 120 days. It is cold-tolerant, drought-tolerant, tolerant of poor soil, and also tolerant of abundant fertilizer and water, disease-resistant, and high-yielding. A single root weighs 2.5 to 3 kg, and the general yield is 3000 to 4000 kg per mu. This variety can be eaten raw or steamed, and is mostly used for pickling; besides being used as a vegetable, it is also used as feed. Locally, it is directly sown in the open field in late May, with a plant spacing of 35 to 50 cm and a row spacing of 70 to 80 cm. It is harvested from late September to early October.
3. Sichuan Yangdatoucai.
The leaf cluster is semi-erect, the leaf surface is smooth, dark green, covered with waxy bloom, and the base of the petiole is purplish red. A single fleshy root weighs 800 g, and the largest reaches 2500 to 3000 kg. It is mainly used for pickling. The growing period is long, and it is drought-tolerant, cold-resistant, and highly disease-resistant.
4. Shandong Rutabaga
It is distributed in Shandong, Hebei, Jiangsu, Zhejiang, Shanghai and other places. There are two types: lobed-leaf and flat-leaf. The lobed-leaf type has flat-spreading leaves and a spherical fleshy root; the root head is dark purple and relatively small; the shortened stem elongates during the harvest period due to the shedding of old leaves (3 to 6 cm); the root neck swells and is light purple, with relatively smooth skin. The taproot portion does not emerge above the soil and is yellow-white or gray-white, with relatively many lateral roots; the developed and enlarged fleshy root weighs 1 to 1.5 kg on average, has relatively good quality, and is extremely cold-tolerant; in Shanghai and Jiangsu, the fleshy root can overwinter in the open field. The flat-leaf type has green skin, the part in the soil is white, half of it is in the soil, and the root is smaller than that of the lobed-leaf type; it is earlier-maturing, the plant is semi-erect, and it can be densely planted; its distribution is not as wide as that of the lobed-leaf type.
5. Nanjing Rutabaga
The leaf cluster is semi-erect; the leaves are long obovate, deeply lobed, with 4 to 5 pairs of small lateral lobes, dark green in color, slightly covered with waxy bloom; the fleshy root is oblate, the epidermis of the part emerging above the ground is light green, and the part in the soil is white. The flesh is white and relatively low in water content. A single root weighs 500 to 1000 g. It is mainly used for stir-frying and pickling, and also used as feed. In the suburbs of Nanjing, it is sown from early to late July, transplanted in August, and harvested from late November to early December.
6. Changsha Rutabaga
It is mainly produced in the Wangcheng area of Changsha and was introduced from Shanghai in the 1950s. The leaf cluster is semi-erect; the leaves are pinnately deeply lobed, dark green in color, and covered with waxy bloom. The fleshy root is spherical, 17.4 cm long and 15.6 cm thick; the epidermis of the part emerging from the soil is purplish red, and the epidermis of the part in the soil is gray-white. The root flesh is white and rich in starch. A single root weighs about 3 kg and is mainly used for pickling. It is late-maturing, with a growing period of 110 to 120 days. It has strong adaptability, is cold-tolerant, not heat-tolerant, likes fertilizer and water, and is disease-resistant. The yield is 1500 to 2000 kg per mu. Locally, it is intercropped with rice, sown for seedlings in early August, and transplanted in early September. The row spacing is 50 cm, and the root spacing is 30 to 40 cm.
　　
　　
II. Cultivation Techniques
　　
1. Cultivation season. Rutabaga is mostly cultivated in autumn or autumn-winter, and can also be sown in spring in colder areas. Provinces in the Yangtze River Basin mostly sow and raise seedlings in early to mid-August; Guangdong, Fujian and other provinces sow in September to October; the Huang-Huai River Basin mostly sows and raises seedlings in early to mid-July; and Hebei generally sows in mid-to-late April.
2. Land preparation and fertilization. Rutabaga prefers loose soil rich in organic matter and with good aeration. After the previous crop is harvested, apply 2500 to 4000 kg of decomposed farmyard manure or 1500 to 2000 kg of human excrement and urine per mu as base fertilizer. In the southern region, after harrowing, turning, and sunning the soil clods, make deep-furrow high beds 1.3 to 1.5 m wide and 15 to 20 cm high.
3. Direct sowing or seedling raising. Rutabaga can be directly sown or raised as seedlings for transplanting. For direct sowing, drill sowing or hole sowing can be carried out according to the local suitable sowing period, with a plant spacing of 26 to 33 cm. For seedling raising and transplanting, the sowing period is generally 7 to 10 days earlier than that of direct sowing, and the seedling age is about 30 days. After the seeds are broadcast, cover with 1 cm of soil, and pay attention to controlling the damage of underground pests. Transplant at the appropriate time, and dig holes 13 cm deep and 13 cm in diameter so that the roots of the seedlings stand upright in the holes. The soil should not be covered too deeply or too shallowly, and it is appropriate to bury up to the base of the cotyledons. After planting, water promptly to settle the roots so as to help the seedlings survive.
4. Fertilizer and water management. Rutabaga has the characteristics of being tolerant of fertilizer, tolerant of poor soil, and having a strong water-absorbing capacity. However, to obtain a high yield, fertilizer and water management must still be strengthened. Increase the application of organic fertilizer. During the vegetative growth stage, apply two topdressings after survival and during the fleshy root enlargement period. Attention should be paid to applying potassium fertilizer, which can be applied during the fleshy root enlargement period. Rutabaga likes moist soil. Water promptly during the seedling stage and the period when transplanted plants are becoming established, and at the same time pay attention to draining waterlogging on rainy days. During the peak growth period of the fleshy root, more water is needed, so it should be irrigated sufficiently in a timely manner, generally once every 5 to 7 days.
5. Harvest. In the northern region, harvesting is generally carried out after a hard frost, and after harvest the roots can be stored by burying them in a trench cellar. In areas of the Yangtze River Basin where winter is not very severe, harvesting is often carried out successively about 100 days after thinning or transplanting, once the aboveground leaf cluster turns yellow, and storage is generally not practiced.