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Allowing weeds to grow among the rubber and consume 
both plant food and moisture can be shown to markedly lessen 
the rapidity of growth of the trees in the plantation. In 
Ceylon, the case of weeding is ori a different footing to that 
which exists on the large majority of estates in the Federated 
Malay States. In the former country the cultivation to some 
extent of the soil by weeding is in itself of value, as the soils . are 
often packed on the surface and prevent the free passage Of air 
and water, the pulling of weeds and scraping the surface is tillage 
which benefits the rubber trees. In the rubber-growing districts 
of Malaya the soils generally are of so porous and friable a 
character that the partial cultivation which weeding gives, is of 
little or no value. On undulating or steep lands the 
disadvantages of constantly disturbing the surface, causing the 
loss of top soil during heavy rainfall, is very marked, and the 
difficulty of making efficient drains is increased by the fact that 
each rainfall means the introduction into the drains of large 
quantities of silt. 
The cost of weeding is becoming a very serious charge, and 
is in fact the heaviest item of expense during the period 
before trees can be tapped. In the second, third and fourth year 
on some estates weeding cannot be efficiently done for much 
under $2 per month per acre. Thus on a r,ooo acre clearing, 
weeding causes a very large annual expense, in some years 
amounting to a charge of over $20,000. 
The relatively high cost of weeding has led some planters to 
abandon weeding, or to weed only partially, either a space round 
each tree or a strip down the line. In these cases the growth of 
grass and other weeds is checked by regular cutting. 
That the presence of grass and other weeds retards, to some 
extent the rapid growth of young rubber can be demonstrated, 
but the fact that on many estates where this treatment has been 
practised the trees are growing vigorously and yielding well, leads 
planters to consider the damage^done by weeds as not sufficiently 
great to justify the cost of their extermination. 
The position in the Federated Malay States is that the only 
object of weeding in rubber estates is to prevent the harmful 
competition of useless plants among the trees. If, however, a 
plant is proved to be not useless but advantageous to the trees 
among which it is growing, then its removal is neither necessary 
nor wise. 
Leguminous plants, i.e., of the Clover, Pea, Crotolaria 
tribe — are characterised by the presence of bacteria in their roots, 
living in what is called symbiotic relationship, i.e., both organisms 
being of mutual service to each other. These bacteria, which 
cause nodules on the roots, absorb free nitrogen from the air, and 
