Environmental temperature of citrus growth The growth, flowering and fruiting of citrus fruit trees are closely related to environmental conditions such as temperature, sunshine, moisture (humidity), soil, wind, altitude, topography and slope direction, which have the greatest influence on temperature. Even if the temperature difference is 0.5℃, sometimes there will be completely different results. The growth and development of citrus fruits need a temperature of 65438 02.5 ~ 37℃. The day and night temperatures of flower bud differentiation in autumn are about 20℃ and 65438 00℃, respectively, and the soil temperature of root growth is roughly the same as the ground temperature.
If the temperature is too low, oranges will freeze. When the sweet orange is at -4℃ and the satsuma orange is at -5℃, the branches and leaves will be frozen. When the sweet orange is below -5℃ and the satsuma orange is below -6℃, the branches will be frostbitten. When the sweet orange is below -6.5℃, the satsuma mandarin will freeze to death.
Slightly resistant to shade, like warm and humid climate, not cold-resistant, freezing injury occurs when the temperature is lower than -8℃, and it is suitable for growing in deep and fertile neutral to slightly acidic sandy loam.
Citrus reticulata is a tree species with strong shade tolerance, but good sunshine is needed for high quality and high yield. Generally, areas with annual sunshine hours 1200 ~ 2200 hours can grow normally. For example, compared with Chongqing citrus producing areas with less sunshine, South China with good sunshine and abundant calories has higher sugar content, lower acid content and higher sugar and acid content.