Reasons for High Yields of Welsh Onion, How It Differs from Scallion, and Pest and Disease Control Methods

Welsh onion is one of the more common foods on our dining tables. Allium vegetables hold an extremely important position in Chinese vegetable production, with their cultivated area accounting for 10% of the total vegetable sowing area and their output accounting for 7% of total production. So what are the reasons for high yields of Welsh onion? Do you know the differences between Welsh onion and scallion? How should pest and disease control in Welsh onion be handled?

I. What are the reasons for high yields of Welsh onion?

1. Choose superior varieties

Choose excellent varieties with good yield performance, strong disease resistance and a pungent taste, such as Jitui onion and Gaojiaobai.

2. Choose the plot

Welsh onion is most averse to continuous cropping. As the farming proverb goes, “pungent after pungent, and you are bound to fail; onion, chive and garlic never meet,” so in arranging the crop rotation, Welsh onion must not be planted after garlic, Chinese chive, onion or other vegetables of the Apiaceae family. It can, however, be intercropped or followed with cabbage, eggplant, winter melon, watermelon or Chinese cabbage. The plot should preferably be loam soil rich in organic matter, with a deep soil layer, high and dry terrain and convenient drainage; Welsh onion grown on such a plot has a pungent taste, a rich flavor and a high yield.

3. Land preparation and fertilization

Apply sufficient base fertilizer: 5000 kg of decomposed farmyard manure and 50 kg of high-phosphorus, high-potassium compound fertilizer per mu. Spread the above fertilizers evenly on the surface of the bed, then plow deeply 20-30 cm, and open furrows with a plow to a depth of 30 cm.

4. Plant at the right time

In the central and southern plains of our province, the most suitable planting period for winter-storage Welsh onion is generally late June to early July. Transplanting is often used in production. Water the Welsh onion seedling bed thoroughly 2-3 days before lifting the seedlings, so that the soil remains neither dry nor wet, making lifting easy without soil sticking to the seedlings. Lift the seedlings and plant them as you go. When planting, the depth should be such that the heart leaf is not buried and 7-10 cm is exposed above the ground; since seedlings vary in size, it is enough to keep the lower part neat and uniform. Generally, 13,000-16,000 seedlings are planted per mu in high-yield fields. Fertile land should be sparser, poor land denser; more fertilizer means sparser, less fertilizer means denser. To make hilling convenient, use the method of widening the row spacing and narrowing the plant spacing. The row spacing is 70 cm and the plant spacing is 5-8 cm.

5. Field management

After the Welsh onion seedlings are planted, the old roots rot quickly, and new roots sprout after 4-5 days; once the new roots grow out, new leaves begin to grow. The early management goal for winter-storage Welsh onion is to promote root growth: first, prevent waterlogging; second, loosen the soil. After the Start of Autumn, the temperature gradually drops, the root absorption function enters a vigorous period, and the plant enters the peak leaf-growing period, so the demand for water and fertilizer increases. From the Start of Autumn to White Dew, the watering principle is “light watering, water in the morning and evening,” and along with watering, apply a “leaf-promoting fertilizer” of 1500 kg of decomposed farmyard manure and 20 kg of nitrogen-potassium fertilizer per mu to promote rapid leaf development. After White Dew, the weather is cool and the temperature difference between day and night increases; Welsh onion enters the period of pseudo-stem formation, which is also the key period for fertilizer and water management. From White Dew to the Autumn Equinox, topdressing is mainly with quick-acting nitrogen fertilizer, preferably urea, at about 20 kg per mu. The watering principle is “frequent watering, heavy watering,” keeping the soil constantly moist to meet the growth needs of the pseudo-stem. After Frost's Descent, the weather grows colder day by day, leaf growth gradually slows, and leaf-surface water transpiration decreases, so watering should be gradually reduced; watering should stop 7-8 days before harvest to improve the storability of winter-storage Welsh onion.

II. Differences between Welsh onion and scallion

Onions are generally divided into Welsh onion and scallion. The north is mainly dominated by Welsh onion, especially as a cooking seasoning; for example, Shandong Welsh onion has thick skin and plump leaves, and sometimes a single Welsh onion can weigh as much as two or three jin. Welsh onion can be used directly as a vegetable for stir-frying, such as Welsh onion stir-fried pork kidney and Welsh onion stir-fried mutton, and so on.

The south mainly has small scallions, also called fragrant scallion; for example, a rather distinctive one is Guangzhou's Xiaoyu onion. Fragrant scallion is quite appealing, relatively smooth and tender, with a somewhat delicate charm, and is usually used as an auxiliary material in cooking dishes; it can be used for tossed tofu, as a seasoning for clear soup, or eaten raw or in cold dishes.

Scallion contains relatively high levels of protein and minerals, and also relatively high carotene; in terms of minerals, scallion has higher nutritional value than Welsh onion. From the perspective of being rich in allicin, Welsh onion has a higher content, so Welsh onion is relatively more pungent and has the effect of promoting appetite and stimulating gastric acid secretion; it also has a very good bactericidal effect and can prevent intestinal diseases.

III. Pest and disease control in Welsh onion

1. Insect pests

The main insect pests of off-season cultivated Welsh onion are leafminer, onion thrips, beet armyworm and so on. Control methods: at the peak of nymph occurrence, spray 10% imidacloprid wettable powder at 2000-2500 times dilution, once every 7-l0d, for 2-3 consecutive treatments. At the early peak of adult occurrence and the peak of larval leaf-mining damage, use 1.8% abamectin emulsifiable concentrate at 2000-3000 times dilution for spray control, once every 7-l0d, for 2-3 consecutive treatments.

2. Diseases

The main diseases are purple blotch, downy mildew, viral disease and so on.

Purple blotch: promptly pull out diseased plants or remove diseased leaves and diseased flower stalks, and bury them deeply or burn them; in the early stage of the disease, spray 75% chlorothalonil wettable powder at 500-600 times dilution, or 70% mancozeb wettable powder at 500 times dilution, or 64% sandofan wettable powder at 500 times dilution, etc.; use the above agents alternately, once every 7-10d, for 2-3 consecutive treatments.

Downy mildew: in the early stage of the disease, spray 25% metalaxyl wettable powder or 75% chlorothalonil wettable powder at 500-600 times dilution, once every 7d, for 3-4 consecutive sprays.

Viral disease: promptly pull out diseased plants found early and bury them deeply or burn them in a centralized way. Strengthen fertilizer and water management, and promptly control aphids. In the early stage of the disease, spray 20% Virus A wettable powder at 500 times dilution, for 2-3 consecutive sprays.