CHAPTER VIII 

 FERTILIZERS 



The proper fertilizing of a fruit plantation is an especially 

 difficult point to determine experimentally, because it is so 

 difficult to determine and to control the conditions surrounding 

 the roots of trees. When it has been determined by experiment 

 what the best treatment for a particular orchard is, this informa- 

 tion is of relatively little value to the owners of other orchards 

 because the many different factors of ' ' soil condition ' ' are likely 

 to vary widely. In this respect the fertilizer problem stands 

 ahead of any other. For example, if it is a question of what to 

 spray with, the conditions surrounding the leaves of the trees 

 are so similar that what is best for Brown's trees will probably 

 also be best for Smith's trees, though he may live five or ten 

 or even one hundred miles away. But the fertilizer question is 

 so complex, and conditions change so decidedly in going even 

 a short distance, that what is good in the way of fertilizers for 

 Brown's trees may not be good for Smith's though his orchard 

 may be just across the road. 



Doubtless further experiment will throw more light on the 

 subject, and we may hope that the time will come when we shall 

 have a generally accepted scheme of orchard fertilization. In 

 the meantime we must use what evidence we have and do our 

 best to gain further light for ourselves by a little personal 

 experimenting. 



The best orchardists believe in fertilizing and practise it in 

 private orchards. But the evidence on the subject is meagre" 

 and conflicting. Three lines of reasoning should lead to the 

 adoption of this attitude until such time as more authoritative 

 evidence on the subject is available. 



Trees Exhaust Soil. — It has been very definitely shown that 



apple orchards take out of the soil far more fertilizer material 



year by year than ordinaiy farm crops do. Professor I. P. 



Roberts has calculated that the twenty-year record of fertilizer 



100 



