How to Manage Welsh Onions in Autumn? Mastering These Four Points Is Key
Welsh onion, scientific name: Allium fistulosum L. var. giganteum Makion), is a type of onion and can be divided into four types: common Welsh onion, multiplier onion, shallot, and tree onion. Welsh onion is pungent in taste and slightly warm in nature, with the effects of inducing sweating to unblock yang, detoxifying and seasoning, promoting sweating and inhibiting bacteria, and dilating blood vessels. It is mainly used for symptoms such as wind-cold common cold, aversion to cold with fever, headache and nasal congestion, abdominal pain due to yin cold, dysentery and diarrhea, internal accumulation of parasites, insufficient lactation, and difficult urination and defecation. Welsh onion contains volatile oil, the main component of which is allicin, and also contains diallyl sulfide and calcium oxalate. In addition, it also contains fat, carbohydrates, carotene, vitamin B, vitamin C, niacin, calcium, magnesium, iron and other components.
Morphological Characteristics of Welsh Onion
Root: The roots are white, string-like, with few and short lateral roots. The number, length and thickness of roots continuously increase with the increase in the total number of leaves produced by the plant. During the vigorous growth period of Welsh onion, the number of roots can reach more than 100.
Stem: The stem is extremely shortened, spherical or flat-spherical, solitary or clustered, 1-2 cm thick, with a white, membranous outer skin that does not split. The upper part bears multiple layers of tubular leaf sheaths, and the lower part is densely covered with fibrous roots. After the growing point at the seedling apex differentiates into a flower bud, it gradually develops into a flower stalk. The flower stalk of Welsh onion is thick and strong, hollow and unbranched, 30-50 cm long.
Leaf: The leaf consists of a leaf blade and a leaf sheath. The leaf blade is long-conical, hollow, green or dark green. A single leaf sheath is cylindrical. Multiple layers of nested leaf sheaths and the 4-6 young leaves not yet emerged from the sheath wrapped inside them form a club-shaped pseudostem.
Flower: Borne at the top of the flower stalk. Before flowering, the developing umbel is hidden within the involucre. In onion plants with fully grown vegetative organs, one inflorescence has 400-500 flowers, and can reach more than 800 in some cases. Bisexual flowers, cross-pollinated. Each flower has 6 tepals and 6 stamens. When the pistil matures, the style is 1 cm long. Ovary superior, 3 locules, with 2 ovules per locule.
Fruit and Seed: The fruit is a capsule, which easily splits when mature. The seed is shield-shaped, black, with 6 ridges and irregular dense wrinkles. The 1000-seed weight is 2.4-3.4 g.
The Four Key Points of Autumn Management of Welsh Onion
The rainy season ends in late August, which is an important period for the growth of autumn vegetables, and field management should be strengthened. The focus of field management of Welsh onion is to promote rooting, strengthen the plant and soften it through hilling, and strengthen fertilizer and water management to create suitable environmental conditions for the formation of the white pseudostem, thereby improving the yield and quality of Welsh onion.
1. Watering: After Welsh onion is planted, it enters a period of high temperature. At this time, the focus of management is to promote rooting, so watering should be controlled, and drainage should be carried out after rain to prevent waterlogging, so as to prevent root rot, yellow leaves and dead seedlings; at the same time, cultivation should be strengthened to promote root growth. From the Beginning of Autumn to the White Dew solar term, the principle of light watering and watering in the morning and evening should be followed. After White Dew, Welsh onion enters its peak growth period, and the principle of frequent and heavy watering should be followed, watering once every 4-6 days. After Frost's Descent, the temperature drops, Welsh onion has basically matured, and the water requirement decreases, so the soil should be kept moist. Stop watering 5-7 days before harvest, which is beneficial for harvest, storage and transportation.
2. Topdressing: On the basis of applying sufficient base fertilizer, Welsh onion also needs topdressing in stages. When the plant growth accelerates after the Beginning of Autumn, apply a “leaf-promoting fertilizer”, applying 1500-2000 kg of decomposed farmyard manure and 20-25 kg of superphosphate per mu to promote leaf growth. After the White Dew solar term, it enters the peak growth period of the white pseudostem, which is the key period for yield formation of Welsh onion. Combined with watering, apply a “plant-strengthening fertilizer” 2 times, each time applying 15-20 kg of urea and 10-15 kg of potassium sulfate per mu, broadcasting the topdressing between the rows, then watering after shallow cultivation.
3. Hilling: Hilling is an important measure to soften the leaf sheaths, prevent lodging, and improve the yield and quality of the white pseudostem. From the Beginning of Autumn solar term to before harvest, generally hill up three times. The first two times are combined with cultivation, pushing the ridge soil into the onion furrow, and after the End of Heat, the furrow is filled level. The hilling height for Welsh onion each time should be determined according to the growth height of the pseudostem, 3-4 cm each time, hilling soil up to the leaf emergence opening of the uppermost leaf, and never burying the heart leaf, so as to prevent leaf rot.
4. Disease prevention: To prevent damage from leaf miners, after seedling recovery, spray dimethoate once every 8-10 days (add 15 ml of dimethoate to every 15 kg of water). When brown spot or gray spot disease appears on the onion leaves, use a 1000-fold dilution of carbendazim spray for control.