A Detailed Explanation of the Causes of Deformed Onions and Their Prevention and Control Methods
Onion, also known as scallion head or round onion, is a fairly common vegetable, and because of its relatively high economic benefits, its planting area is becoming wider and wider. However, deformed conditions appear during the planting process, which seriously affects the commercial value of onions and brings economic losses to farmers. So what are the causes of deformed onions? Below, let's take a look at the prevention and control methods with the editor, to reduce losses to a minimum.
1. Seed causes
Onions have been cultivated for a long time and there are many varieties. In many areas, when introducing varieties, the local environment was not taken into reference, resulting in discomfort between the seeds and the local environment. For example, varieties with weaker winter hardiness are more sensitive to low temperatures; when introduced to areas with a lower annual average temperature, they will bolt as soon as they encounter low temperatures; while varieties with strong winter hardiness need to sense low temperatures before they bolt and flower.
Prevention and control methods: choose excellent varieties suitable for the local environment for cultivation, and according to the variety's response to temperature levels and day length, select varieties suitable for local planting.
2. Climatic causes
Onion is a typical biennial plant of the seedling vernalization type. Only when the seedling grows to a certain degree will it respond to low temperatures. If cold air or relatively low temperatures are encountered during this stage, it will cause the seedling to shift from vegetative growth to reproductive growth. Over time, vernalization will occur and cause bolting and flowering. If the temperature is too low, the temperature cannot fully complete vernalization, causing abnormal differentiation of the bulb and resulting in deformed growth.
Prevention and control methods: strengthen management, and use greenhouse methods to artificially control the temperature so that vernalization is complete and bulb growth is promoted.
3. Nutritional imbalance
When fertilizer application favors nitrogen fertilizer and irrigation is excessive, it will cause seedling spindling, inhibit or delay bulb formation, and during low-temperature periods it will also cause early bolting and flowering. When nitrogen fertilizer is insufficient and the soil is dry, the seedlings grow weakly and enter reproductive growth early, showing bolting and flowering, which can also cause deformed bulbs.
Prevention and control methods: fertilization should be reasonable, especially the amount of nitrogen fertilizer applied should be controlled. Apply nitrogen fertilizer in the early stage to promote seedling growth, but it should not be excessive. In the middle and later stages, apply less or no nitrogen fertilizer, and increase the application of phosphorus and potassium fertilizers, which can increase yield.
4. Planting too deep
During the planting process, planting too deep or too shallow will lead to abnormal bulb growth or poor development. If planted too deep, leaves grow too vigorously, the base of the bulb thickens, and the bulb is too small and deformed; if planted too shallow, the plant is prone to lodging, and the bulb may also be exposed above the ground, and over time it will turn green and crack.
Prevention and control methods: the planting depth must be appropriate, not too deep or too shallow. Loose soil can be planted somewhat deeper, and heavy clay soil should be planted appropriately shallow.
The above is an introduction to the causes of deformed onions and their prevention and control methods. We hope it can help you. To learn more related knowledge, please stay tuned to us.