Detailed Explanation of Key Technical Points for Spring Radish Cultivation and Management
Radish, a root vegetable, also known as laifu or water radish, with a fleshy root that is oblong, spherical or conical. It originated in China, and there are numerous varieties, with green skin, red skin and white skin. It has multiple culinary and medicinal values.
Morphological characteristics of radish
Biennial or annual herb, 20-100 cm tall; taproot fleshy, oblong, spherical or conical, outer skin green, white or red; stem branched, hairless, slightly powdery. Basal leaves and lower stem leaves lyrately pinnatifid, 8-30 cm long, 3-5 cm wide, terminal lobe ovate, lateral lobes 4-6 pairs, oblong, with blunt teeth, sparsely coarsely hairy; upper leaves oblong, serrate or nearly entire. Racemes terminal and axillary; flowers white or pink, 1.5-2 cm in diameter; pedicels 5-15 mm long; sepals oblong, 5-7 mm long; petals obovate, 1-1.5 cm long, with purple veins, lower part with a claw 5 mm long. Silique cylindrical, 3-6 cm long, 10-12 mm wide, constricted between seeds and forming spongy transverse septa; beak at apex 1-1.5 cm long; fruiting pedicel 1-1.5 cm long. Seeds 1-6, ovate, slightly flattened, about 3 mm long, reddish-brown, with fine reticulate veins. Flowering period April-May, fruiting period May-June.
Radish stem erect, stout, cylindrical, hollow, branched from the base. Basal leaves and lower stem leaves have long petioles, usually lyrately pinnatifid, coarsely hairy, lateral lobes 1-3 pairs, margins serrate or incised; middle and upper stem leaves oblong to lanceolate, gradually smaller upward, not divided or slightly divided, not clasping the stem. Racemes, terminal and axillary. Flowers pale pink or white. Silique, indehiscent, nearly conical, straight or slightly curved, constricted between seeds into a bead-like form, apex with a long beak, beak 2, 5-5 cm long, fruit wall spongy. Seeds 1-6, reddish-brown or yellow, round, with fine reticulate veins.
Key points for spring radish cultivation and management
Select good varieties
Choose varieties with a short growing period, strong cold resistance, late bolting and low susceptibility to hollowing. At present, there are many radish varieties suitable for spring cultivation, among which Baiyuchun, Chunbaiyu, Spring Radish 9646 and Changchun Daigen are better.
Land preparation and bed making
Choose relatively loose soil, apply 3000 kg of decomposed organic fertilizer and 30 kg of ternary compound fertilizer per mu. Apply the fertilizer all at once before land preparation, then plow and prepare the land. Shape the bed surface into a turtle-back form, with a bed height of 25-30 cm and a width of 1 m, planting two rows per bed, with a plant spacing of 30 cm and a row spacing of 40 cm.
Sowing at the right time
When cultivating spring radish, the sowing period should be strictly controlled, and sowing too early must be avoided, because under low-temperature conditions the plants are prone to premature bolting. In general, sowing should be done when the surface soil temperature reaches above 10°C. In actual production, it can be flexibly controlled according to the cultivation facilities and the selected varieties. For cultivation in greenhouses, sowing can be done from late January to mid-February, and harvesting begins in early April; for open-field cultivation with plastic film mulching, sowing can be done from mid-March to early April, and harvesting from mid-May to early June; for cultivation in small arched sheds covered with plastic film, the sowing period can be advanced to early to mid-March. Hole sowing should be used at sowing, with 1-2 seeds per hole, and the sowing rate per mu is 100-200 g. After sowing, cover with 0.5 cm of fine soil, then cover with plastic film.
Field management
Seedlings emerge 4-5 days after sowing. After emergence, the film should be broken in stages and batches in time to let the seedlings out, and thinning should be done when the seedlings grow to the 2-3 leaf stage. About 20 days after sowing, the fleshy root of the radish begins to expand; at this time, mud clumps should be used to press down the openings in the film to prevent the film from being lifted. The suitable growth temperature for spring radish is above 12°C. Management in the early growth stage should focus on heat preservation, appropriately raising the temperature in the shed to promote the growth of rosette leaves, and additional cold protection materials should be added when strong cold air occurs. In the late growth stage, when the temperature rises, ventilation and cooling should be carried out in time, keeping the temperature in the shed at 20°C-25°C during the day and around 15°C at night, and gradually removing the small shed film and the greenhouse skirt film according to weather conditions. After mid-April, the shed film can be removed and open-field cultivation carried out.
Spring radish generally does not need watering during the growth process; only when the soil in the furrow turns white should it be watered appropriately. During the fleshy root expansion period, radish has a relatively large water requirement, and irrigation can be carried out according to soil moisture conditions, preferably by drip irrigation. If furrow irrigation is used, it should be carried out at noon on a sunny day, irrigating half the furrow, and draining it dry 2 hours after irrigation. The first topdressing is carried out 30 days after sowing, and the second topdressing about 45 days after sowing. During topdressing, 25 kg of compound fertilizer per mu can be made into a liquid fertilizer with a concentration of 0.5% and used to irrigate the roots; if the soil moisture is relatively high, it can be applied in holes 10 cm away from the radish roots.
Pest and disease control
The main pests are aphids and cabbage caterpillars, which can be controlled with pesticides such as imidacloprid and insecticidal agents. The main diseases are downy mildew and black rot, which can be prevented by measures such as crop rotation and enhanced ventilation. If chemicals are used to prevent diseases, for downy mildew, solutions such as copper hydroxide and mancozeb can be sprayed alternately; for black rot, solutions such as agricultural streptomycin and copper preparations can be used to irrigate the roots.
Harvest at the right time
When the fleshy root reaches a diameter of more than 5 cm and weighs about 0.5 kg, it can be harvested in batches for market. When harvesting, leave 3-5 cm of the petiole and cut it off, wash before marketing; if transporting over long distances, do not wash.
A small reminder: removing the growing point of white radish can increase yield
By removing the growing point of white radish, it is possible to inhibit its premature entry into the reproductive growth stage and prolong its vegetative growth period, so that the nutrients supplied to the growing point are redirected to promote the expansion of the fleshy root, greatly increasing the yield. According to experiments, compared with white radish whose growing point was not removed, the yield per mu of white radish with the growing point removed can be increased by about 2000 kg.
The specific method is:
40 to 50 days before the normal harvest of white radish, that is, when the white radish has grown to 0.25 to 0.5 kg, choose a sunny day, use a small knife, insert the tip of the knife into the center of the radish heart leaves, and dig out the growing point. If the heart leaves dug out do not scatter, it proves that the growing point has been reached. 5 to 7 days after digging, after the wound heals, apply 2000 to 2500 kg of manure water per mu, adding 50 to 100 g of urea per 50 kg of manure water. Be careful to apply it to the side of the radish, and do not pour the manure water onto the radish, so as to avoid wound infection by pathogens and rotting.
Check once every 10 days; if the growing point is still growing, a second core removal can be carried out. About 1 month before harvest, that is, when the radish has grown to 0.75 to 1 kg, conduct a third check; if the growing point has not been completely removed or lateral buds have grown out, carry out one more supplementary removal. The main purpose of removing the core is to stop the radish from growing new leaves, and it can also keep the radish fresh for 3 months. If sold around the Spring Festival, the price is high, and it can also help adjust market supply and demand.