236 



TROPICAL AGRICULTURE 



CHAP. 



Proportion The leaves contain only from a half to three quarters per 

 cocarnein ^^^^* °^ cocalnc, SO that large quantities are consumed every 

 the leaves, year in the manufacture of the alkaloid alone. 



The best 

 soil. 



The best 

 climate. 



Germina- 

 tion. 



Distances. 



General 

 principles of 

 cultivation. 



Soil and Climate. — The coca shrub is hardy ; and, al- 

 though it will grow on many kinds of soil, for its successful 

 cultivation a rich and light soil is necessary. Well drained 

 moist loams rich in humus are the most suitable ; and, as 

 the plants exhaust the land, judicious manuring will be ne- 

 cessary after heavy crops are reaped. Although the shrub 

 is a native of the highlands of South America, one variety 

 of it has been found to thrive at sea level in the West Indies 

 in places where the air is usually moist and the soil suitable, 

 but the lower slopes of the hills produce leaves richest in 

 the alkaloid. 



Propagation. — The plant will grow from cuttings ; but 

 when it is cultivated to any extent, seedlings should be raised 

 in nurseries. The beds are prepared in the usual way, and 

 the seeds are strewn on the surface and lightly covered with 

 fine earth. The seedlings are to be protected from the sun 

 by the erection of thatched roofs in the manner described 

 under the head of cinchona, and frequent watering is neces- 

 sary until the plants are strong. The seeds will germinate 

 in about a fortnight after sowing, and the plants may be put 

 out into the fields when they are from eight to ten inches 

 high. 



Cultivation. — The land having been well tilled, so as to 

 destroy the weeds and to render the soil light and free, the 

 seedlings are planted at distances of six feet from each 

 other, and this will allow over 1,200 shrubs to the acre. 

 The employment of the general principles of cultivation is 

 all that is required, for the plants do not need any special 

 treatment. 



Crops. — The first harvest may be looked for at the end of 

 eighteen months from the time of planting, and the shrubs 



