Agriculture Reference
In-Depth Information
USA. His contributions number 17 out of the 25 cultivars and clones now
established in Hawaii. Today, the litchi is found in most countries of Latin
America, the Caribbean, India, Mauritius, Africa, Australia, Israel, the Canary
Islands, Madeira Islands, and many other countries.
ECOLOGY
The litchi and longan are evergreen subtropical plants, indigenous to areas
where cool, dry winters and warm, wet and humid summers prevail. Such
conditions are found mostly in subtropical regions and at higher elevations
in the tropics. In Guangzhou, summers are known for their rains and high
humidity (>80%) during night and day. The winter is cool and dry, and frost is
rare. Litchi is described as a water-loving, low-elevation plant, which is planted
largely along the banks and dykes in the Pearl River delta in Guangdong.
However, there are upland cultivars (mountain litchi) grown on hillsides or in
orchard systems with very little tillage after the trees mature.
Soil
Observations indicate that the litchi and longan thrive on a wide variety of soil
types as long as drainage is good enough to prevent waterlogging. Satisfactory
litchi growth occurs in India and Florida in neutral to slightly alkaline soils,
with free lime present. In south China, the litchi soils are alluvial silty loams
to clays in the Pearl River delta or laterite soils on the hills. Longan thrives best
on deep clay loams, and both species prefer a slightly acid (pH 5.0-6.5) soil.
Climate
Rainfall and moisture
High rainfall and humidity induce good growth in litchi and longan, with
litchi being able to resist fl oods. Roots of litchi trees covered with water for 8
days showed no deleterious ef ects, even when fruiting. In China and Thailand,
litchis are also grown on banks with high water tables beneath them.
Ample annual rainfall is considered to be around 1250-2000 mm for
litchi and 1500-3000 mm for longan. When rainfall is lower, irrigation is
essential. A dry autumn and winter is important to prevent litchi vegetative
growth (Fig. 9.1), which is essential to good fl owering (Nakata and Watanabe,
1966). In south China, litchi anthesis occurs during the rainy season
(130-375 mm/month) and when relative humidity is higher than 80%. Too
much rain during anthesis, however, can reduce fl ower opening and insect
activities needed for pollination. A major problem of litchi culture in Hawaii,
with the exception of the Kona district of Hawaii, is that rainfall comes in
late autumn and winter, making it dii cult to control vegetative fl ushing.
