What kind of climate conditions does longan cultivation require?

AbstractLongan likes to grow in a warm and humid environment, and is suitable for cultivation in subtropical areas, mildly warm areas, and areas without severe frost. Temperature has a certain influence on the growth, development, flowering, and fruiting of longan. Areas with an annual average temperature of 20-22°C are most suitable for growing longan.

Longan has relatively high requirements for its growing environment. Generally, it is only suitable for cultivation in subtropical areas and mildly warm areas where the climate has no severe frost. Because of its environmental requirements, it is known as a famous fruit of Lingnan. The longan fruit can be eaten fresh directly or used medicinally, and market demand is relatively large.

1. Characteristics and features of longan

The longan tree is an evergreen tree. Their trees are tall, and the leaves are mostly even-pinnately compound leaves, with leaflets opposite or alternate; the panicles are terminal or axillary, the fruit is spherical, and the seeds are glossy black.

Their flowering period is from March to April, and the fruiting period is from July to August. They like a warm environment. An annual average temperature of 20-22°C in the growing environment is more suitable for their growth and development. In areas where the annual average temperature is below 17.5-18°C, the average temperature of the coldest month is below 10°C, and the absolute low temperature is below minus 5°C, longan is relatively difficult to survive. They have a certain drought resistance. Areas with annual precipitation of 1000-1600 mm are most suitable for growing longan. Their requirements for soil are not very high.

2. Temperature requirements

Temperature directly affects the growth and development, flowering and fruiting, and geographical distribution of longan. Longan is suitable for cultivation in areas with an annual average temperature above 20°C. Growing longan at this temperature can achieve relatively good economic benefits.

In China's Yibin area of Sichuan, the annual average temperature is only 18.4°C, but this area has no continuous frost in winter and a long frost-free period, and the absolute low temperature is above minus 1°C, so it is also an economic cultivation area for longan.

If the temperature drops to 0°C, longan seedlings are prone to frost damage. When the temperature drops to minus 0.5°C to minus 4°C, large longan trees will suffer frost injury to varying degrees. The specific degree of frost damage is related to the geographical environment. Trees on hillsides suffer less frost damage than trees planted on flat land and low land; trees on the south and southwest sides suffer less frost damage than trees on the north and northeast sides; trees with sufficient water sources nearby suffer less damage than trees without sufficient water sources; young trees suffer more damage than mature trees; trees with strong vigor and dense canopies suffer less damage, and even if they suffer frost damage, they recover relatively quickly.

In early spring, longan growth requires a period of low temperature of 8-14°C to promote flower bud differentiation. If this temperature range is exceeded, the higher the temperature, the longer the flower bud differentiation time, and the more likely the longan tree is to show the phenomenon of “flushing shoots.”

When longan is flowering, it needs a temperature of 18-27°C. When the temperature is 25-32°C, the branches and shoots of the longan tree grow faster, the sugar content in the fruit is higher, and the quality is also better.

3. Water requirements

Longan has a certain drought resistance. They like a warm and humid environment, but are afraid of waterlogging. In their different growth and development stages, their water requirements also differ. From November each year after the autumn shoots mature to April of the following year, the water requirement is relatively low, so as to avoid the growth of winter shoots, allow more nutrients to accumulate in the branches and leaves, and promote flower bud differentiation, flower spike emergence, and flowering and fruit setting; in other growth stages, especially in July-August, the water requirement is relatively high. If water is insufficient, it will affect the growth and development of the root system and branches and shoots, and will have a certain impact on fruit yield and quality. If water is lacking in the later stage of fruit development, it will lead to fruit cracking and fruit drop.

Longan has relatively strong drought resistance. Short-term flooding of the orchard will not affect the longan tree, but if there is long-term standing water in the orchard or the groundwater level is too high, the longan root system will suffer suffocation and root rot, and tree vigor will also decline.

4. Soil requirements

Longan has relatively low soil requirements. It can also grow when planted in barren, dry, acidic hilly red soil. Hilly red soil has deep soil layers, good drainage and aeration, and sufficient sunlight. If deep plowing and soil improvement are carried out, and more organic fertilizer is applied to the soil, longan can grow better and yield can be increased.

When planting longan on sloping land, it is best to choose the southeast, south, and southwest sides for building the orchard, to avoid wind damage and cold damage to the longan trees, and at the same time do a good job in soil and water conservation to promote the growth and development of longan.

5. Orchard site selection

Choose slightly acidic soil with loose and deep soil layers, moist soil, and rich organic matter. The best pH value is controlled between 5.5-6.5. According to the growth characteristics of longan, the orchard requires sufficient sunlight, but the fruit should be properly shaded. The canopy of the longan tree is relatively large, so measures against wind damage and freezing damage should be taken well when building the orchard.