( 4 ) 
The above table shows that the area of land per 
head of population under rice is only about one-fifth 
of an acre, whereas roughly half an acre is required 
to support one adult for a year. Thus, the only 
self-supporting States are Kedah, Kelantan and 
Perlis, chiefly because Malays are predominant in 
these States. 
The area under rice varies slightly from season 
to season, the main cause of variation being the 
incidence of rainfall. 
Irrigation. Water supply is the chief factor in 
rice cultivation, and irrigation on a 
small scale is a common practice, the Malays dis- 
playing remarkable aptitude in diverting small 
streams so as to get the maximum utility from 
them. Temporary weirs formed of logs, bamboos, 
matted sticks and earth are frequently constructed 
to deviate part of the water of rivers into distribu- 
tion channels for irrigating fairly large areas. In 
many places the cultivation is dependent on the 
annual flooding of rivers. In other places various 
contrivances (water wheels etc.) have to be erected 
to lift water from lower levels. In some areas 
adjustable dams have been constructed and else- 
where fixed bunds serve to conserve the rainfall. 
Regular controlled irrigation is the ideal, but this 
condition only exists in a few areas of which Krian, 
comprising 56,000 acres, is by far the largest. Hill 
rice is absolutely dependent on regular rainfall 
during the growing period. 
