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no artificial aids to get rid of excess of water the structure allowing 

 water to percolate freely while not being to loose to partially retain it. 



Drainage is a factor the importance of which the planter has 

 learnt by experience. If the soil is water-logged and consequently not 

 sufficiently aerated rubber roots will not grow vigorously. 



He has still to learn the advantages of protecting his soil from sun 

 and rain or rather the disadvantages of exposing it to these inimical 

 influences. His drains are made chiefly to decrease the loss of surface 

 soil after rain but if he will cover his land with a beneficial weed the 

 only drains that will be necessary will be those on flat land which pre- 

 vent the land becoming waterlogged. 



Nearly all the expenses of draining are thus saved and a sum of 

 from $1/- to $1- per acre in order to permanently establish a protective 

 plant which will obviate the necessity for drains on sloping land and 

 at the same time encourage the root growth of his rubber trees, can readily 

 be afforded, especially as it means a cessation of all expense in regard 

 to weeding or attending to drains. 



Millions of dollars have been spent on keeping the land on which 

 rubber is growing exposed and probably three quarters of the labour force 

 have been used in carrying this out. Hundreds of thousands of tons 

 of top soil, which can never be replaced and the value of which as plant 

 food is immense have been washed off clean weeded estates. 



Is this expenditure of money and labour and sacrifice of top soil 

 necessary in order to get the most rapid and vigorous growth of rubber 

 trees? This is a problem which any planter can solve himself. Let 

 him the next time he is opening a clearing sow or plant a selected green 

 manure Crotalaria, Mimosa (sensitive plant) Vigua, Desviodium &c, or 

 even Passiflora foctida (passion flower) directly the burning is finished 

 and see that it is established so that the ground is never exposed to 

 the sun and the rich top soil which is left behind when jungle is burnt 

 is not immediately washed off. Let him plant his rubber in this and 

 compare its height and girth and general vigour with the growth of 

 rubber trees of equal age in his clean weeded cleai ings and I have no 

 doubt that he will be convinced that the labour and money spent on 

 clean weeding is not a sound commercial investment. 



If he establishes his selected plant at once there is no fear of 

 lalang that bug bear of the rubber getting admission. 



During the past three years I have been making observations as to 

 rubber which for various reasons has been allowed to remain in weeds 

 or has had other plants growing with it which tend to protect the soil 

 from sun and rain. In cases where the weed is lalang the benefit 

 of the protection of the soil is to a great extent counteracted by the 

 damage done by this, the worst of all the weeds of Malaya. 



Lalang forms a close mat of roots which absorb a great of deal 

 of rain and dew, the leaves of the plant do not protect the soil nearly 

 as well as almost any other plant, being all arranged vertically and thus 

 giving as little shade as possible. I have found the surface temperature 

 in lalang to be some eight to ten degrees higher than in other weeds 

 sensitive plant, passion flower &c, on similar soil. 



Even where lalang is the weed the liiuderance to the rapid growth 

 of the rubber is not so marked as believers in clean weeding would 



