60 TROPICAL AGRICtJLTURE 



districts of heavy rainfall, the use of arsenite of soda has been 

 adopted in destroying weeds. This chemical method of de- 

 stroying weeds is much cheaper than mechanical methods and 

 in seasons of almost continuous rain can be applied with- 

 out injuring the soil, whereas cultivation of the muddy soil 

 would not only not destroy the weeds but would injure the 

 texture of the soil. The practice of stripping the lower leaves 

 from the cane at two or three periods during the growth of 

 the crop has been practiced quite commonly on some of the 

 Hawaiian plantations and elsewhere, but the results show that 

 this practice is of doubtful value. Cane leaves by analysis as 

 well as by field experiments have been shown to have large 

 value in nitrogen and humus for the maintenance of soil fer- 

 tility. 



The harvesting season for cane varies in different countries. 

 It extends over a rather long period in Hawaii, commonly from 

 December to the following September. In Louisiana, the har- 

 vesting season extends from October to January. The tas- 

 seling of cane marks the end of growth. Cane may, however, 

 be allowed to stand for at least six months after tasseling be- 

 fore any loss of sugar occurs. There is a great variation in 

 the yield of cane per acre in different countries, the limits of 

 variation being perhaps 6 and 120 tons. In Louisiana, the 

 yield is about 20 tons, in Java about 40, and in Cuba about 17. 

 Hawaii has perhaps the highest yield. The average yield of 

 sugar per acre in Hawaii is 45^ tons and the average peld of 

 cane is about 50 tons. In Hawaii, yields of 15 tons of sugar 

 per acre have been obtained in localities where the soil and 

 climatic conditions are especially favorable. The number of 

 tons of cane required to produce a ton of sugar naturally de- 

 pends on the percentage of sugar in the juice and purity of 

 the juice. In Hawaii, from 8 to 10 tons of cane are required to 

 produce a ton of sugar. 



Thus far no successful cane harvester has been devised, 

 although repeated efforts have been made to perfect a machine 



