THE QUESTION OF FERTILISATION 95 



an improvement is observable in both the quantity 

 and the quality of the fruit. 



Here again everything depends upon the estate 

 and the region in which it is situated, for a fertiliser 

 that proves highly successful in one case might be 

 practically valueless in another. The formulae 

 recommended by scientists must usually be put to 

 practical tests before their suitability can be 

 ascertained. But one thing is certain scientific, 

 systematic fertilisation can be made to increase 

 the yield of trees by anything from 5 to 20 per 

 cent. 



The need of adequate supplies of water at all 

 times cannot be too strongly emphasised, says 

 Coconuts : The Consols of the East. ' Water must 

 be constantly at the disposal of the palms, to 

 convey in solution the plants' mineral and nitro- 

 genous raw food from the root to the crown. The 

 quantity of mineral food which the tree takes up 

 is roughly proportional to the amount of water 

 which it absorbs. Increasing the plants' trans- 

 piration has, then, the same effect on them as apply- 

 ing a fertiliser to the ground ; without the water 

 the fertiliser will do little or no good." 



Continuous aspiration is accompanied by con- 

 stant transpiration. Calculations made by an 

 American expert of the total water transpiration 

 of an entire tree per day show that it varies from 

 28 to 75 litres. Even at the former rate the 



