Detailed Explanation of Key Techniques for Off-Season Cultivation of Yellow Chives with Plastic Mulch
Yellow chives, also known as "chive sprouts," "yellow chive sprouts," or "yellow chives," commonly called "chive white," are the product of chives that have been blanched through softening cultivation and turned yellow. When chives are cut off from light and grown entirely in darkness, they cannot carry out photosynthesis or synthesize chlorophyll due to the lack of sunlight, and thus turn yellow; this is called "yellow chives." Because they grow without sunlight and appear yellow-white, their nutritional value is inferior to that of chives. They belong to the Liliaceae family, a perennial herbaceous plant, and the seeds and leaves are used in medicine. They have effects such as strengthening the stomach, refreshing the mind, stopping sweating and astringing, tonifying the kidney and supporting yang, and securing essence. They are distributed throughout the country.
Nutritional Components of Yellow Chives
Yellow chives are rich in protein, sugar, the minerals calcium, iron and phosphorus, provitamin A, vitamin B2, vitamin C and nicotinic acid, as well as glycosides and bitter substances. They have the effect of dispelling cold and dissipating blood stasis, enhancing physical strength, and can also increase appetite, strengthen bones and tendons, and treat injuries. However, people with yin deficiency and internal heat or eye diseases should avoid eating them.
Dietary Therapeutic Effects of Yellow Chives
Tonifying the Kidney and Warming Yang
Yellow chives are warm in nature and pungent in taste, with the effect of tonifying the kidney and raising yang, so they can be used to treat conditions such as impotence, spermatorrhea and premature ejaculation.
Benefiting the Liver and Strengthening the Stomach
Yellow chives contain special components such as volatile essential oils and sulfides, giving off a unique pungent aroma that helps regulate liver qi, increase appetite and enhance digestive function.
Promoting Qi Flow and Regulating Blood
The pungent odor of yellow chives has the effect of dissipating blood stasis and invigorating blood, and promoting qi flow and relieving stagnation, and is suitable for conditions such as traumatic injuries, nausea, enteritis, vomiting blood and chest pain.
Moistening the Intestines and Relieving Constipation
Yellow chives contain large amounts of vitamins and crude fiber, which can wrap up hair, sand grains, metal shavings and even needles in the digestive tract and expel them with the stool. They are known as the "intestinal cleansing grass," treating constipation and preventing intestinal cancer.
Key Points for Off-Season Cultivation of Yellow Chives with Plastic Mulch
Yellow chives are produced by cultivating chives under dark, lightless conditions, yielding a pale yellow product that is fiber-free, fresh and tender in quality, and delicious in taste; it is a relatively premium vegetable. Traditional methods of producing yellow chives are mostly tile-tube softening, soil-earthing softening, and grass-shed softening. In recent years, agricultural technical departments have demonstrated a new technique of producing yellow chives by covering with black plastic mulch, achieving notable results. After mulching, the soil temperature under the film can increase by 3°C to 5°C, which is favorable for the growth of yellow chives. Using chive clumps that need crop rotation due to root jumping, covering them with black plastic mulch can produce 2 to 3 seasons of off-season yellow chives, marketed from October to December, which is exactly the "off-season" for vegetables, so the price is good and they sell well. With the black plastic mulch covering technique, yellow chives are produced with high yield and good quality: 700 to 750 kg per mu for the first crop, 500 to 600 kg for the second crop, and 200 to 300 kg for the third crop.
Selection of Chive Plots: Select chive plots that have been planted for about 4 years and need crop rotation and replanting due to root jumping during growth; generally three crops of yellow chives can be harvested. Chive plots that are in the peak leaf-producing period and have not yet reached the rotation period are generally not used for off-season yellow chive production.
Black Plastic Mulch Covering: Mulching can be done from late September to early November, but mulching in late October is best. If mulched too early (such as before mid-September), rotting easily occurs due to high temperatures; if mulched too late (such as after mid-November), yellow chives stop growing due to chive dormancy, and no yield can be obtained. Bamboo frames can be used for the arched sheds; the planting area is divided into beds 1.3 to 1.5 m wide, and black plastic mulch is laid over the arched frames every 1.5 m, with both sides pressed tightly with fine soil to prevent light leakage. Note that covering should not be done after rain in high temperatures or when the bed soil is too wet, to prevent root rot and seedling death. After covering, ventilation openings must also be set at both ends of the plastic arched shed, with additional light-shielding boards, to prevent direct sunlight from entering the shed. Also, on both sides of the arched shed, place a tile tube flat every 3 m to facilitate ventilation and regulate temperature and humidity.
Field Management: Fertilization should be carried out 15 to 20 days before covering, applying 30 to 40 kg of nitrogen-phosphorus compound fertilizer per mu by furrow application or hole application, while controlling watering to prevent excessive soil moisture. After covering with black film, no more topdressing is done, to avoid leaf rot caused by ammonia volatilization due to high temperatures in the shed; pest and disease control and other field management measures are the same as for field chives.
Timely Harvesting: When yellow chives are about 25 cm tall, just beginning to show clump spreading, and dry tips appear on the leaves accompanied by a sticky, moist appearance, they must be harvested immediately; otherwise, root rot and leaf death can occur within a short time, or even the entire clump may rot completely. Generally speaking, as the temperature decreases, the number of harvest days increases accordingly; at high temperatures, they can be harvested in 7 to 9 days, with the longest period not exceeding 15 to 17 days.