( 17 ) 
retain the heaviest rainfall during any period. A 
somewhat common error is to place the pits too near 
the foot of the hill, thus allowing a considerable 
movement of soil from top to bottom. 
Terraces and bunds are probably better adapted 
to extremely steep slopes and should be laid down 
with a due consideration of contours. 
In terracing, the establishment on the slopes of the 
terraces of a suitable cover crop or of weeds and 
grass other than lalang, should be carried out. A 
method of conserving soil which has been practised 
on estates in Sumatra and on at least one estate 
in Malaya is that of bunding. 
The bunds are constructed by digging contour pits; 
the soil from these is used in the construction of 
a series of bunds, the site and frequency of which 
are determined by the slope of the land. After the 
main bunds are constructed, careful watch has to 
be kept, after heavy rainfall, in order to deal with 
any particular points, such as the heads of the 
ravines, which require special treatment. These 
methods, applied to undulating and hilly land, are 
of value not only in the conservation of the surface 
soil, but also in the retention of the rainfall in situ , 
an important factor in rubber cultivation. 
It is important, however, that such methods should 
be applied if possible at an early stage in the 
planting up of an estate and not after much of the 
surface soil has already been removed. 
It is important to realise that wash removes the 
entire top soil and not merely certain constituents; 
consequently the damage cannot be entirely repaired 
by manuring. 
. 61-48 /« 
