Detailed Explanation of Key Techniques for Spring Purple Cabbage Cultivation
Purple cabbage is a variety of cabbage, grown for its purplish-red heads. It originated along the Mediterranean to North Sea coasts of Europe, prefers cool conditions and is fairly cold-tolerant, and can be cultivated both in the open field and under protected conditions. It has the characteristics of firm heads, bright color, strong adaptability, high yield and good quality. In the Nanjing area, spring purple cabbage cultivation is sown from mid-December...
Purple cabbage is a variety of cabbage, grown for its purplish-red heads. It originated along the Mediterranean to North Sea coasts of Europe, prefers cool conditions and is fairly cold-tolerant, and can be cultivated both in the open field and under protected conditions. It has the characteristics of firm heads, bright color, strong adaptability, high yield and good quality. In the Nanjing area, spring purple cabbage can be sown from mid-December to mid-March of the following year, harvested from early June to early July, with a yield of 2500-3000 kg per 667 sq m and an income of 4000-4800 yuan. The spring purple cabbage cultivation techniques are described below.
1 Variety selection
Choose varieties with strong winter hardiness, spring-sowing type, early maturity and high yield. At present, the varieties used for spring cabbage cultivation in China include Purple Gan No. 1, Zaohong, Hongmu, etc. According to cultivation technique research at our institute, Purple Gan No. 1 has strong winter hardiness, early maturity, good quality and high yield, and is suitable for early-maturing cultivation in the Nanjing area.
2 Timely sowing and raising strong seedlings
In the Nanjing area, mid-December is the suitable sowing period, and seedling raising under protected conditions prevents premature bolting. Broadcast sowing is used for seedling raising, with a seeding rate of 50 g per 667 sq m and a seedbed area of about 16 sq m. After sowing, water thoroughly and cover with plastic film to raise the bed temperature and promote germination. The seedling-raising period for spring purple cabbage is short and requires relatively high temperatures. In the early stage, pay attention to ventilation during the day, maintaining 15-20°C; at night, protect against cold, maintaining a temperature of about 5°C to control the vernalization process. Before transplanting, carry out low-temperature hardening; as long as there is no frost damage, lower the temperature as much as possible to adapt to the early spring open-field environment.
For fertilizing the seedling bed, use 20 kg of urea and 40 kg of compound fertilizer per 667 sq m. After application, shallowly turn the soil twice to mix it fully with the soil. After sowing, level it by stepping on it with a footboard, then spray water and cover with film. Seedlings emerge after one week; remove the film. Thin the seedlings once each at the heart-break stage and at the 2-true-leaf stage, with a seedling spacing of about 6 cm. When thinning, pay attention to thinning the dense and keeping the sparse, thinning the weak and keeping the strong. After thinning, water and apply topdressing according to weather conditions to promote robust seedling growth.
3 Land selection and transplanting
Choose a sunny plot with high, dry terrain and good drainage, and fertile soil rich in organic matter with good water retention, with a pH of 5.8-6.9 being suitable.
Apply 5000 kg of decomposed barnyard manure and 100 kg of compound fertilizer per 667 sq m as base fertilizer. After fertilizing, plow once, then rake flat and break up the soil clods, and make high beds with deep furrows, with a bed width of 2 m. Transplant at a row and plant spacing of 40 cm square, planting 3500 plants per 667 sq m. When seedlings are 15 cm tall with 6-7 true leaves, transplant them into the greenhouse around February 28. Immediately after transplanting, water to settle the roots, and at the same time pay attention to timely re-watering to ensure survival.
4 Field management
After spring cabbage is transplanted, because the temperature is relatively low, apart from watering to help the seedlings recover, generally do not irrigate much. In terms of temperature management, 7-10 days after transplanting, keep 25-27°C during the day and 13-15°C at night. Cultivate twice to maintain soil moisture and higher soil temperature and promote root development. During the seedling stage and rosette stage, keep the soil alternately dry and moist. In the late rosette stage, to control excessive vegetative growth of stems and leaves and promote head-leaf differentiation, early-maturing varieties should be given appropriate seedling restraint, but not for too long, which can control early bolting. Entering the heading stage, to promote rapid growth of the heads, keep the soil moist frequently, and combine watering with additional topdressing. Apply 15 kg of urea and 10 kg of calcium-potassium fertilizer per 667 sq m, or spray the heads with 0.2% potassium dihydrogen phosphate, once every 7-10 days, for 2 consecutive sprays. In the mid-growth period, cultivate and weed twice in time; you can also spray the plant leaves with ABT yield-increasing agent at 6 mg/L, Fengchansu at 2000 times dilution, or Pen Shibao at 5000 times dilution to regulate purple cabbage growth. Early-maturing varieties have a short heading stage, and the head leaves gain weight quickly in the early stage, so topdressing should be applied early; no further topdressing is needed in the mid-heading stage.
5 Pest and disease control
During the heading stage, soft rot is likely to occur. Remove diseased plants promptly when found. In the early stage of the disease, spray with 72% agricultural streptomycin sulfate soluble powder at 3500 times dilution, once every 7-10 days, for 3 consecutive sprays. To control cabbage caterpillar, use 40 g of 5% cypermethrin emulsifiable concentrate plus 60 kg of water per 667 sq m for spraying. To control diamondback moth, use 60 g of 0.5% abamectin wettable powder plus 60 kg of water per 667 sq m for spraying. To control aphids, use 15 g of 10% imidacloprid wettable powder plus 60 kg of water per 667 sq m for spraying.
6 Timely harvest
Harvest in early June. When the heads are firm, harvest in batches in a timely manner and finish harvesting within 1 month, otherwise the heads are prone to cracking or rotting. The yield per 667 sq m reaches about 2700 kg.