86 PHILIPPINE AGRICULTURE 



The sheet is then fastened around a wooden cylinder, the 

 rough side outward. This cylinder is turned rapidly in- 

 side a larger cylinder or rounded box, with the roots be- 

 tween the two. 



Yield. The average yield of each plant should be fully 

 5 kilos of roots, or more than 60 tons to the hektar. 

 Thirty per cent of the weight of the roots should be 

 starch, and three quarters of this can be easily washed 

 out. Tapioca is the finest starch made from the maniok 

 plant. 



POTATO 



History of the Potato. The potato, whose name is 

 Solaiium tuberosum, is also a native of tropical America, 

 but it grew there only in the mountainous regions. It was 

 in cultivation by the Indians as far north as Virginia. 

 The potato ranks with maize and tobacco as one of the 

 plants which thrive in many different climates. Al- 

 though native in the tropics, it is an important crop in 

 Canada. 



Conditions of Growth. The potato was introduced long 

 ago into the Philippines, but it has not been well culti- 

 vated, and therefore has never become an important crop. 

 Except on very light or well-drained soil, it can be grown 

 only in the dry season. When there is not too much 

 water, it thrives on heavy soil, which should not be poor 

 in lime. 



Planting. The potato tuber is not a root, but an under- 

 ground stem. Its nodes are marked by the " eyes." 

 Branches or new plants can grow from these, just as from 



