Techniques for High-Yield and High-Quality Cultivation of Chinese Chives with Plastic Mulch
Chinese chives are one of the vegetables most favored by urban residents in Northwest China throughout the year. In recent years, due to inadequate management measures by some farmers, the quality of fresh Chinese chives and chive flower stalks has declined year by year. Some farmers have applied excessive amounts and misused chemical pesticides, causing pesticide residues in Chinese chive products to exceed the standard, posing a serious threat to the health of consumers. Over the past 3 years, in order to effectively implement pollution-free production and achieve high yield, high quality and high efficiency, through in-depth comprehensive production demonstrations, a pollution-free high-quality Chinese chive cultivation production base has been comprehensively established within the demonstration area, and the following key cultivation technical measures have been adopted:
1. Select suitable cultivation areas to establish concentrated pollution-free Chinese chive planting sites, and carry out pollution-free production area certification.
2. Select excellent varieties. For plastic mulch cultivation of Chinese chives, choose Lanzhou Early Stalk Chives and Malian Chives, which have medium to strong tillering ability, dark green leaf color, thick pseudostems, thick leaves, early stalk emergence, and excellent quality.
3. In production, adopt the method of seed propagation, seedling raising and transplanting, and minimize the method of dividing and replanting mother plants. Through comparative observation in recent years, seed-raised and transplanted plants have vigorous growth, good product quality, and obvious yield advantages.
(1) Do a good job at the seedling raising stage and cultivate strong seedlings. When sowing, select pure, plump new seeds for sowing. The seedling raising and sowing plot should be applied with 5000 kg of high-quality farmyard manure per mu in the previous autumn and winter, and irrigated with sufficient winter water. In the following spring, apply 10 kg of urea, 50 kg of ordinary superphosphate, and 10 kg of potassium sulfate per mu. After plowing, level and prepare the soil for sowing. Around March 20 to April 10 each year, use dry seeds for broadcast sowing. For transplanting, the seed rate is 0.5-0.8 kg per mu, requiring 67 sq m of seedling bed. Strive for even sowing, cover with soil 1-1.5 cm thick, and irrigate once every 3-4 days after sowing until emergence to ensure the soil surface remains moist.
(2) Strengthen seedling stage management. The focus of seedling stage management is watering and weeding. When Chinese chives emerge, water lightly once, and water again after the soil surface turns white. As the seedlings grow, gradually extend the watering interval and increase the amount of water. From full emergence to a seedling height of 16 cm, water about once every 7 days, and apply 5 kg of urea per mu with the water. After the seedlings reach about 10 cm in height, promptly pull weeds in the seedling bed 2-3 times to promote the growth of Chinese chives.
(3) Transplanting method and post-transplanting management. In Northwest China, transplanting is generally carried out from late July to early August (if the chive seedlings are weak and small, they can be transplanted in early spring of the second year). When transplanting, adopt the single-row deep-furrow planting method. Before transplanting, water the seedling pond thoroughly, lift out the chive seedlings, cut off the tips of the fibrous roots leaving 2-3 cm, and cut off 2/3 of the leaves to reduce leaf surface evaporation. Open furrows at a row spacing of 40 cm, with a furrow depth of about 15 cm. Place the seedlings in the furrow at a plant spacing of 1-1.5 cm, water, and cover with soil. When planting, the depth of soil covering should not bury the tillering node. After earthing up, the chive furrow should be about 4-6 cm lower than the inter-row space, so as to facilitate yearly earthing up for high yield. After planting, water continuously twice, promptly loosen the soil to promote root development, and thereafter keep the soil alternately dry and moist. When Chinese chives reach 15 cm in height, apply 10 kg of diammonium phosphate per mu with watering, and then apply fertilizer again after an interval of 20 days. After the Beginning of Autumn, the weather becomes cooler, so water control should be carried out in a timely manner, and sufficient winter water should be applied before the soil freezes.
4. Implement the key techniques for promoting vigorous growth and early sprouting. The purpose of plastic mulch covering of Chinese chives in early spring is to promote early sprouting and early market supply to achieve high benefits from seasonal differences. Therefore, in cultivation measures, 3 key measures are emphasized: First, for Chinese chives planted in the first year, implement management measures of not harvesting to nourish roots and promote vigor. Second, in each cultivation year, after harvesting 2-3 cuts in spring and summer, do not harvest fresh Chinese chives for market in autumn, in order to accumulate nutrients back into the chive roots, ensuring early growth and rapid development after mulching in early spring and excellent quality of fresh Chinese chives. Third, after 4-5 years of production, carry out renewal and rejuvenation by re-raising seedlings and transplanting. Only in this way can the yield and quality advantages of fresh Chinese chives and chive flower stalks be continuously maintained.
(1) Mulching method. In the second year after planting, cover the entire field on the chive ridges with plastic film 1.8-2 m wide in mid-February, seal the plastic film tightly between rows with bricks and soil clods, and harvest the first cut in mid-to-late March. After harvesting, loosen the soil around the chive stubble and gradually earth it up around the chive roots. After the first harvest, let it dry in the sun for 1 day before covering with plastic film again. After the second cut, remove the plastic film, begin harvesting the third cut in early May, and harvest chive flower stalks for market from early June to mid-to-late August.
(2) Water and fertilizer management. 2-3 days after each harvest, when the chive wounds have healed and new leaves have grown, water and apply fertilizer: 400 kg of decomposed organic fertilizer, 10 kg of urea, and 10 kg of compound fertilizer per mu. During the period of harvesting chive flower stalks, pay attention to water management, with the basic principle of keeping the soil alternately dry and moist.
(3) Strengthen summer and autumn management. After the harvest of chive flower stalks ends in mid-to-late August, promptly turn and sun-dry the chive roots. The method is to use a wooden stick to lift the chive leaves and make them fall to one side of the row, then turn them to the other side of the row after half a month, and repeat this turning and sun-drying 3 times. After the early frost kills the aboveground leaves, cut off the withered aboveground leaves in mid-October, then begin ploughing, fertilization control, and management for the next year.
(4) Apply heavy base fertilizer in winter. Before winter irrigation, apply 100 kg of ammonium bicarbonate and 40 kg of superphosphate per mu and turn them into the furrows. At the same time, apply heavy "muffled head" fertilizer: 8 cubic m of high-quality decomposed farmyard manure per mu, to provide sufficient nutrients for the sprouting of Chinese chives in early spring, help raise soil temperature, and lay the foundation for a bumper harvest the following year.
6. Pest and disease control. In the production of pollution-free Chinese chives, pest and disease control technology is a key link. It is necessary to thoroughly use safe, low-toxicity, low-residue chemical pesticides, strictly master the appropriate application timing and effective dosage, and strictly control the safe interval between pesticide application and harvest.
The main pests and diseases of mulched Chinese chives are chive maggot, gray mold, and Phytophthora blight.
Chive maggot: Use vinegar solution to trap and kill adults; prepare a solution with sugar, vinegar, alcohol, water, and 99% trichlorfon crystals in a ratio of 3:3:1:10:0.6, place 2-3 basins per mu, replenish at any time, and use it to trap and kill during the peak emergence period of seed flies. For field chemical application, it can be carried out 2 days after the first cut in mid-to-late March or in late autumn in mid-to-late September. Commonly use 50% phoxim emulsifiable concentrate at 1000 times dilution or 90% trichlorfon crystals at 1000 times dilution poured along the furrow to the roots (spraying the root area).
Gray mold: Spray 50% procymidone wettable powder at 1000 times dilution or 50% iprodione wettable powder at 1000 times dilution on the second day after harvesting chive flower stalks.
Phytophthora blight: Spray 60% metalaxyl wettable powder at 600 times dilution or 72.2% propamocarb aqueous solution at 600-800 times dilution on the second day after harvesting Chinese chives.