96 THE QUESTION OF FERTILISATION 



annual transpiration of an average tree would be 

 approximately 2,250 gallons. Mr. Herbert Walker, 

 writing on the same subject in the Philippine 

 Journal of Science, says : "It seems that the 

 nutriment comes, not from the soil in which the 

 trees are actually growing, but from an inexhaus- 

 tible supply of water, laden with plant food. . . . 

 The underground water supply would account for 

 the flourishing condition of trees in a sandy soil 

 near the sea, even in times of drought, when 

 individuals further inland in higher and less 

 permeable ground would be dying from want of 

 water." 



Fish manure, when it can be obtained in good 

 quality and at a reasonable cost, is strongly 

 recommended as the best for coconut trees. Bone 

 dust is also excellent, but the price practically pro- 

 hibits its use on ordinary estates. Guano is not 

 only very costly, but also too strong, and rapidly 

 exhausts itself. Certainly crops improve soon 

 after it is applied, but this is only for a compara- 

 tively short period, and to secure good results the 

 quantities of this fertiliser have to be successively 

 increased. Whenever used, however, the Peruvian 

 variety is considered the best, because it is more 

 easily soluble, and disintegrates more readily. 



As the trees come into bearing, they will require 

 large quantities of potash and phosphorus, these 

 elements entering largely into the composition of 



