Welsh onion is a shallow-rooted crop, and its root groups are mainly distributed within 30 cm of topsoil, which has strong adaptability to soil, but sandy loam with loose soil, good air permeability and rich organic matter is the easiest to obtain high yield.
Although the root system of Chinese onion is weak in absorbing fertilizer and water, it belongs to a fertilizer-loving crop. The absorption ratio of nitrogen, phosphorus and potassium is (65-75): (13-15):100. Generally, every 500㎏ scallion needs to absorb nitrogen.
Attention should be paid to increasing the application amount of nitrogen and phosphorus fertilizer in production. In addition, sulfur, calcium, magnesium, manganese and boron have significant effects on the yield and quality of green onions.
Fertilization management should be based on sufficient base fertilizer and topdressing according to the law of fertilizer demand in each growth period. It is advocated that organic fertilizer should be the main base fertilizer, and nitrogen, phosphorus and potassium should be applied together, and attention should be paid to the application of trace fertilizers. Topdressing should be based on available nitrogen fertilizer, with light before and heavy after, and supplemented after attack.
Fertilization management techniques for scallion;
In order to realize the annual supply of green onions, there are different stubbles in actual planting. According to the different harvest time, the cultivation stubble of Welsh onion mainly includes open cultivation in autumn and winter, delayed cultivation in autumn greenhouse and early cultivation in spring greenhouse. Affected by climate and cultivation environment, fertilization management should also be treated differently.