WEED COVERINGS 235 



must be done to keep down weeds and weeding expenses. 

 Where lalang has not been thoroughly got rid of, the before- 

 mentioned coverings can scarcely be relied on to suppress it 

 and are a hindrance to its removal if there. 



In the case of Ceylon, owing to the rocky soil, planters seem 

 to have more difficulty in keeping their weeds in check there 

 than anywhere else. In Sumatra, however, no difficulty is 

 experienced by many planters in pursuing a policy of encour- 

 aging the growth of light weeds on hilly ground and yet keeping 

 them under sufficient control. The light weeds are from time 

 to time dug into the soil and thus supply a most valuable green 

 manure, which in the case of light soils greatly improves their 

 texture, and in the case of clay soils aerates them and helps 

 towards a freer circulation of both air and water. In this, as 

 in many other matters, no universal law can be laid down. 



