The King of Anti-Cancer: Fertilizer Selection for Welsh Onion Cultivation, Dosage per Mu, and Topdressing

Welsh onion, also known as four-season onion or green onion, is a relatively common vegetable in China. Because of its effects such as detoxifying and seasoning, and preventing cancer, it is widely used as a seasoning, but to grow Welsh onion well, management work such as water and fertilizer must be strengthened, so what fertilizer is good for growing Welsh onion? About how much fertilizer is needed per mu? What fertilizer is good for topdressing?

I. Fertilizer requirement of Welsh onion:

Generally, under high-yield conditions, Welsh onion can reach 5000-6000 kg/mu, so Welsh onion has a high demand for nutrients. Under normal circumstances, every 1000 kg of Welsh onion produced requires 2.7-3.3 kg of pure nitrogen, 0.5-0.6 kg of phosphorus pentoxide, and 3.3-4.0 kg of potassium oxide. The absorption ratio of nitrogen, phosphorus, and potassium is 1:0.4:1.3, and it is very sensitive to potassium and nitrogen nutrition.

II. Base fertilizer for Welsh onion

The base fertilizer for Welsh onion is mainly decomposed organic fertilizer. Apply 3000-4000 kg of decomposed compost or barnyard manure per mu, 30-40 kg of superphosphate, and 20 kg of potassium sulfate or 100 kg of plant ash. In addition, broadcast 2 kg of copper sulfate and 1 kg of boric acid per mu before land preparation, spread them and plow them into the soil, then shallow plow and harrow finely so that the fertilizer and soil are fully mixed.

III. Topdressing for Welsh onion

Topdressing Welsh onion should follow the principle of light early, heavy in the middle, and supplementary later, and should be combined with intertillage, hilling, and watering. From the Beginning of Autumn to White Dew is the period of vigorous leaf growth for Welsh onion, so apply “leaf-promoting fertilizer” to ensure leaf growth and promote high quality and high yield of Welsh onion.

1. For the first topdressing of Welsh onion at the Beginning of Autumn, apply 3000-4000 kg of farmyard manure or 150-200 kg of cake fertilizer per mu, or 10-15 kg of urea.

2. For the second topdressing at the End of Heat, apply 50-100 kg of cake fertilizer, 30 kg of superphosphate, and 100 kg of plant ash per mu, then intertill, hill up soil, and water after application.

3. From White Dew to Frost's Descent is the tillering stage of Welsh onion, that is, the formation stage of the white stalk. The growth amount and fertilizer requirement of Welsh onion are both relatively large, so heavy topdressing is needed. Apply one tillering fertilizer each at White Dew and Autumn Equinox. For the third topdressing at White Dew, apply 10-15 kg of urea, 100 kg of plant ash, or 10-15 kg of potassium sulfate per mu.

4. For the fourth topdressing at Autumn Equinox, apply 15-20 kg of urea or 20-30 kg of three-element compound fertilizer, 100 kg of plant ash, or 10-15 kg of potassium sulfate per mu.

IV. Fertilization methods for Welsh onion

According to the habits of Welsh onion fibrous roots of seeking fertilizer, water, and warmth, the correct fertilization method can be summarized as three steps: “scatter beside the roots, press with hilling, dissolve by watering.”

1. Scattering beside the roots means evenly scattering fertilizer on the surface soil at the roots of Welsh onion in the ridges while weeding and loosening the soil;

2. Pressing with hilling means hilling soil toward the roots of Welsh onion after scattering fertilizer to cover the fertilizer, reduce fertilizer loss, promote the softening and growth of the white stalk, and enhance the wind resistance of the plants;

3. Dissolving by watering means watering within two days after hilling so that the fertilizer dissolves in the soil and decomposes quickly for the growth of Welsh onion.

V. Foliar fertilization for Welsh onion

To strengthen the disease resistance of onion seedlings, a filtered aqueous solution of plant ash can be used for foliar spraying to supplement potassium fertilizer. Dissolve 8 kg of plant ash in 15 kg of water per mu, then dilute the filtrate with 150 kg of water and spray on the leaves, once every 7-]0 days, for 2-3 consecutive sprays. A 0.2% potassium dihydrogen phosphate solution can also be used for spraying, making the onion seedlings grow vigorously and improving disease resistance and wind resistance.