Is Hengyang, Hunan suitable for growing onions?

Onion has strong adaptability and is suitable for planting in Hengyang, Hunan.

First, the growth environment of onions

(1) Temperature: Onions have strong adaptability to temperature. Seeds and bulbs can germinate slowly at 3 ~ 5℃ and start to germinate at 65438 02℃. The suitable temperature for seedling raising is 12 ~ 20℃, the leaf is 18 ~ 20℃, and the bulb is 20 ~ 26℃. Strong seedlings can tolerate the low temperature of -6 ~ 7℃. Bulbs need higher temperature to expand, and bulbs can't expand below 15℃. The optimum growth temperature is 2 1 ~ 27℃. If the temperature is too high, it will grow and decline and enter dormancy.

(2) Illumination: Onion is a long-day crop, which needs more than 14 hours of long-day sunshine during bulb expansion and bolting flowering. Under the condition of high temperature and short sunshine, only leaves grow and onions cannot form. The suitable light intensity of onion is 20000 ~ 40000 lux.

(3) Moisture: Onions should be supplied with sufficient moisture during germination, seedling growth and bulb expansion. However, water should be controlled at seedling stage and before overwintering to prevent seedlings from growing white and suffering from freezing injury. Irrigation should be controlled before harvest 12 weeks to enrich bulb tissue, accelerate maturity and prevent bulb cracking. Onion leaves are drought-tolerant, suitable for 60% ~ 70% humidity, and diseases are easy to occur if the air humidity is too high.

(4) Soil and nutrition: Onion has strong adaptability to soil, and is suitable for using fertile, loose and well-ventilated neutral loam. Sandy loam is easy to obtain high yield, while clayey loam has full bulbs, good color and storage resistance. The root system of onion has a weak ability to absorb fertilizer, so it needs sufficient nutritional conditions to achieve high yield. Every1000kg onion needs to absorb 2kg nitrogen, 0.8kg phosphorus and 2.2kg potassium from the soil. The application of trace elements such as copper, boron and sulfur can significantly increase the yield.

Second, Hengyang has a subtropical monsoon climate with four distinct seasons and abundant precipitation. It is cooler and more comfortable in spring and autumn, and wetter in spring. Winter is cold and slightly wet, with occasional low temperature rain and snow. Summer is very hot and humid. The annual average temperature is about 18℃, and the annual average precipitation is about 1352 mm.