part of Sri Lanka, Burma, Thailand , Vietnam
and Philippines archipelago and the South
part of lndonesia fall under the latter (7).
Physiographic features such as degree
of slope, aspect, soil depth, rockiness
ect., influence growth and yield of rubber
(7). Rubber has extensive root system with
taproots that could be as deep as 3-4 meters
(B). The 5 years old rubber plantation, root
concentration was seen in the top 18 cm
layer. Horizontally the roots were found up
to 200 cm away from the plant base (9). So
that, a fairly deep, well drained soil with good
physical structure on a gently sloping terrain
with minimal soil erosion is required by
rubber for optimum growth (8). However,
the rubber tree can withstand soil physical
conditions ranging from stiff clayey with
impeded drainage to well drained sandy loam.
Fragile soil with high clay particle such as
clay loam is the most suitable texture (7),
because clay particle has a high water
retention and rich in plant nutrient element
compare to silt and sand particles. However,
the low fertility of soil can be improved by
adding fertilizer in appropriate proportion of
plant nutrient element and right in quantity.
Plant growth is directly affected by
the presence of gravel by impeding root
development and seedling emergence and