4 



trees grow quife well up to the time tapping is started, and after 

 that they almost eease putting on girtli, even if they are only lightly 

 tapped. 



On such trees improvement is a necessity. They are simply 

 starved, the bark-renewal is bad, and if they do not get some 

 nourishment it is only a question of time when the flow of latex will 

 cease, if not altogether, then anyhow to such an extent, that the 

 profit per acre will be very much reduced, which, of course, is the 

 wrong way to go. 



There are thousands of acres with that sort of starved trees 

 in the Peninsula. As far as I have seen the south is considerably 

 worse than further up country, but there are some everywhere, and 

 I think that something more could ho done to resuscitate those trees 

 than has hitherto been the case. 



To start manuring on a large scale before it has been properly 

 ascertained what the soil is lacking is not wise, and before going 

 to such expense it would be the natural thing to tiy to improve 

 matters by cultivation. 



Wlien a young hilly plantation on old lalang land has been kept 

 pei'fectly clean for some years big quantities of the top-soil have 

 been washed away, leaving the ground hard, and under such 

 conditions the trees are unable to get the full benefit from the more 

 or less scanty supply of plant food present. 



The chief object of cultivation is to prepare the soil in such a 

 way that absorbable plant food can be formed and held until used 

 by the plants. 



As a whole, the question of nutriment of plants is very extensive 

 and complicated, and I shall, therefore, on this occasion, confine 

 myself to the mentioning of a few facts. 



It is common knowledge that all plants require, in order to live, 

 the following ten elements : oxygen, hydrogen, carbon, nitrogen, 

 sulphur, phosphorus, potassium, calcium, iron and magnesium, or 

 what is easier to remember, four bases, potash, lime, magnesia and 

 iron dioxide and four acids, carbonic acid, sulphuric acid, intric 

 acid and phosphoric acid. 



The plants obtain their supply of carbon chiefly by assimilation 

 of carbonic acid through the leaves, and the leguminous and a few 

 other kinds of plants are able, aided by bacteria, to assimilate and 

 utilize the free nitrogen from the atmosphere, but otherwise all 

 plant food is taken from the ground, mostlj' dissolved in water, but 

 in some instances dissolved by the acid exuded by the young rootlets. 



A small amount of carbonic acid contained in the water is 

 assimilated ])}' the roots of plants, but besides tliis carbonic acid is of 

 some use in the ground, mostly by bringing inorganic matter into 

 solution. 



