20 



soil and the first results of a heavy wash are, as is 

 frequently to be seen on an old plantation on hilly 

 ground, that these side-roots become exposed (see fig-. 8). 



These are indications that such plantations do not 

 produce latex throughout the year as in the case of 

 Hevea planted on the level. Terracing, or the plantation 

 of other trees in horizontal girdles around the hills is 

 not practised anywhere (see fig. 9). I only saw one 

 instance of the use of cover plants for the purpose of 

 protecting the surface soil against erosion and will deal 

 with the subject subsequently. 



The attention paid to the preservation of the surface 

 soil is therefore confined to the making of surface drains, 

 called in Java "Vanggoten". Sometimes these drains are 

 cut in semicircles, forming canals round each tree. In my 

 opinion, however, a better method was one employed on 

 an estate in Perak. The drains were laid at right angles 

 to the direction of the slope in such a way that they 

 were always in the same horizontal level. The vertical 

 distance between them was always 25 feet, so that on the 

 steeper slopes, the drains, measured along the surface, 

 would lie much nearer to each other than on the flat. 

 The expenditure on these "Contour Drains" would work 

 out at about $ 10 an acre ; and the annual maintenance 

 was increased about $ i an acre. Exact figures are 

 not obtainable, as the maintenance is reckoned in with 

 the weeding. 



Attention should be drawn to the danger of erosion if 

 timely measures are not adopted. The opinion of such a 

 very competent critic as Mr. KELWAY BAMBER, who has 

 had much experience in tropical cultivation, is that 

 everything possible should be done to keep the surface 



