Key Technical Points for High-Yield Spring Cultivation of Carrots
The carrot (carrot), also known as red radish, clove radish, and hulu fujin, and also called hulu fu, red beet, yellow radish, etc., is an umbelliferous biennial herbaceous plant, grown as a vegetable for its fleshy root. Every 100 grams of fresh carrot weight contains 1.67-12.1 mg of carotene, 5-7 times higher than that of tomatoes. After consumption, it is digested and broken down by the stomach and intestines into vitamin A, and can prevent and treat night blindness and respiratory diseases. It can be stir-fried, boiled, eaten raw, pickled in sauce, salted, etc., and stores well. It is distributed throughout the world; it is cultivated in both northern and southern China, and its output ranks second among root vegetables. It can fight cancer and is known as the underground “little ginseng”.
Introduction to spring-sown carrot varieties:
1. Hongxin No. 4. This hybrid has relatively vigorous aboveground growth and dark green leaves; the growth period is 100 to 105 days, with strong winter hardiness and low susceptibility to bolting; the fleshy root has a bluntly rounded tail, a smooth exterior, and fresh red skin, flesh, and core, with an inconspicuous cambium layer; the fleshy root is 18-20 cm long, 5 cm in diameter, and weighs 200-220 g per root; it tolerates low temperatures, expands quickly at low temperatures, and has strong stress resistance, with a yield of about 4000 kg per 667 sq m. In North China, spring sowing is generally carried out from late March to early April, and in protected greenhouse cultivation it can be done from late February to early-to-mid March; other regions can sow at the appropriate time according to local temperatures.
2. Hongxin No. 5. A hybrid with dark green leaves and vigorous aboveground growth; relatively strong bolting resistance, with a growth period of 100 to 105 days; the fleshy root is smooth and uniform, with a bluntly rounded tail, fresh red skin, flesh, and core, and a thin core column; the fleshy root is 20 cm long, 5 cm thick, and weighs about 220 g per root, with a yield of 4000-4500 kg per 667 sq m; its carotene content is relatively high, 2-3 times that of New Kuroda Five Inch, with 110-120 mg of carotene per kilogram of carrot; it has a high dry matter content and good taste, and is suitable for fresh eating, dehydration, juicing, and other processing uses. The sowing period is roughly the same as that of Hongxin No. 4.
3. Hongxin No. 6. A hybrid with strong but not excessive aboveground growth and dark green leaves; the growth period is 105 to 110 days, with extremely strong bolting resistance, suitable for spring open-field sowing in most areas of China or overwintering cultivation in small arched sheds in southern regions; the fleshy root is smooth and uniform, columnar; the skin, flesh, and core are deep fresh red, with a thin core column and good taste; the fleshy root is 22 cm long, about 4 cm thick, and weighs about 200 g per root; the yield is about 4000 kg per 667 sq m; its carotene content is 3-4 times that of New Kuroda Five Inch, with total carotene of 140-170 mg/kg, of which β-carotene content is 100-120 mg/kg, making it an ideal variety for fresh eating and processing.
4. Chunhong No. 1. The variety has a growth period of 100-150 days, strong winter hardiness, rapid root expansion, and early coloring; the fleshy root's skin, flesh, and core are fresh red, the core column is thin, and the root tail is bluntly rounded; the root is 18-20 cm long, about 5 cm in diameter, and weighs 200-220 g per root; the variety has strong adaptability and good taste, with a yield of about 4000 kg per 667 sq m. In North China, open-field sowing is done from late March to early April.
5. Chunhong No. 2. The variety has a growth period of about 90 days and is an early-maturing variety; the root shape is a uniform column, the exterior is smooth, and the skin, flesh, and core are all fresh red; the root is 18 cm long and 5-6 cm in diameter; it is an early-maturing, heat-tolerant variety suitable for spring and summer cultivation, with a yield of about 3500-4000 kg per 667 sq m, suitable for spring sowing cultivation in most areas of China; in the northern part of North China, spring open-field cultivation can be carried out in early April, and in the southern part of North China, spring open-field sowing should be done in late March.
Cultivation key points
1. Spring sowing should not be too early or too late; generally sow when the average daily temperature is 10 degrees C and the average nighttime temperature is 7 degrees C. For protected cultivation, this can be flexibly adjusted according to the temperature inside the greenhouse or small arched shed.
2. Spring sowing has low soil temperature, making it difficult to sprout, so seed soaking and sprout acceleration are advisable in production. The method is to soak the seeds in 30-40 degrees C warm water for 3-4 hours, then remove them and place them in a moist cloth, and keep them at a constant 20-25 degrees C to accelerate sprouting. Be careful to keep the seeds moist, and stir them regularly and rinse them with warm water so that temperature and humidity are uniform. Once most seeds have whitened, they can be sown. The sowing depth should be 2-3 cm; too deep makes emergence difficult.
3. Carrots are root vegetables, so the sowing plot should be sandy loam or loam, deeply plowed and finely harrowed, with a tillage depth of no less than 25-30 cm. Fertilization should be mainly basal fertilizer, applying 2500 kg of decomposed organic fertilizer per 667 sq m, plus 15 kg of phosphorus and potassium fertilizer and quick-acting nitrogen fertilizer. Topdress twice, respectively at the seedling thinning stage and the root expansion stage. The first time, apply 3 kg each of phosphorus and potassium fertilizer and nitrogen fertilizer; the second time, apply 3.5 kg of phosphorus and potassium fertilizer and 7.5 kg of nitrogen fertilizer. From sowing to emergence, keep the soil moist, watering once every 3-4 days, and afterward once every 10-15 days.
4. During the carrot seedling stage, thin the seedlings twice. The first time is when there are 1-2 true leaves, removing inferior, weak, and overly dense seedlings; the second time is when there are 3-4 true leaves, and final thinning is done immediately after, with a plant spacing of 8-10 cm and row spacing of 15-20 cm. Cultivation and weeding are key to high carrot yields; herbicides can also be used for weeding, usually by spraying the soil surface with 100 g of 50% prometryn wettable powder mixed with 25 kg of water per 667 sq m. When cultivating, be careful to mound soil to prevent the fleshy root from emerging above the ground and forming a green shoulder.
High-yield cultivation techniques
1. Choose good varieties: It is advisable to choose high-yield, high-quality varieties suitable for spring sowing, such as “Red Beauty”, “Japanese Kuroda Five Inch”, etc. 2. Choose a good plot, prepare the land, and fertilize: Choose fertile sandy loam with good drainage. Before land preparation, apply 4000 kg of decomposed organic fertilizer and 50 kg of ternary compound fertilizer per mu. The organic fertilizer must be fully decomposed and finely crushed, and spread evenly over the whole area and thoroughly mixed with the soil; otherwise, it will damage the main root. 3. Ridging: After applying enough basal fertilizer and leveling the land, ridges can be made. Ridge specifications: ridge width 50 cm, height 20 cm. Before ridging, first open two furrows and apply 30 kg of ternary compound fertilizer per mu, turning it into the soil while ridging. 4. Sowing and film mulching (1) Seed treatment: Use seed soaking to accelerate sprouting. Soak the seeds in 40-45 degrees C water for about 2 hours, then remove them and keep them at 20-25 degrees C, maintaining moisture and turning them frequently. Once most seed radicles are exposed, they can be sown. (2) Sowing: For spring sowing, generally sow when the 10 cm soil temperature remains at 12 degrees C. Sow two rows per ridge, with a row spacing of 20 cm on the bed surface. Sow the seeds evenly along the furrows and cover with 0.5-1 cm of soil. Generally, 250 g of seed is used per mu. (3) Spray herbicide: 33% pendimethalin EC can be sprayed on the ground; do not miss or repeat the spray. (4) Film mulching: To increase the emergence rate, immediately cover with plastic film after spraying the herbicide, and remove the film in time before emergence to harden the seedlings. 5. Field management (1) Thinning and final thinning: 20 days after sowing, when 2-3 true leaves have grown, thin the seedlings to a spacing of 5 cm. When the seedlings have 5-7 true leaves, do final thinning to a spacing of 10 cm. (2) Topdressing: Generally fertilize twice during the growth period, at the 3-4 true leaf and 7-8 true leaf stages. Apply 30 kg of ternary compound fertilizer each time, opening furrows in the middle-lower part of the ridge shoulders, applying it in, and then covering with soil. (3) Watering: Before emergence, keep the ground moist; generally do not water too much, and properly restrain seedling growth; during the period of vigorous leaf growth, appropriately control watering; during the fleshy root expansion period, maintain a sufficient water supply. Note that the ground must not alternate between dry and wet, to prevent root cracking. (4) Mounding: Mound soil before the fleshy root expands so that the root is buried in the soil, to prevent it from turning green from light exposure and reducing quality. 6. Harvest: Harvest once the fleshy root has fully expanded. Harvesting too early affects yield, while too late makes the fleshy root tissues age, easily forming a pithy core and reducing quality.