THE APPLICATION OF NITROGEN-CARRYING FERTILIZERS 209 



applications and fruit bud formation, for the amount of shoot growth is 

 greatly influenced by the available nitrate supply. The work of Hookeri"*' 

 and others showing the importance of the synthesis and storage of organic 

 compounds in late summer and fall in determining the amount and char- 

 acter of growth early the next season suggests still further indirect correla- 

 tions — correlations no less important, though less easily recognized, than 

 those first mentioned. 



Influence of Nitrogen on the Setting of Fruit. — The influence of 

 nitrogenous fertilizers on shoot and leaf growth and on the formation 

 of fruit buds is not less striking than their effect on the setting of fruit, 

 especially in rather weak trees that still bloom heavily. This is well 

 brought out by the data presented in Table 69, for apple trees in the Hood 

 River valley. 



Table 69.— Influence of Nitrate of Soda Applications upon Set of Fruit in 

 '_/ Two Hood River (Oregon) Apple Orchards 



{After Lewis and Allen^-^) 



^The setting of fruit in the fertilized plots ranged from 100 to 300 per 

 cent, higher than that in the check plots. Furthermore this influence 

 was evident right after blossoming, certainly not later than the time of 

 the so-called June drop. This was only a very short time after applica- 

 tion and shaws the prompt response obtained from such a quickly avail- 

 able fertilizer. Similar results have attended the spring use of nitrate 

 of soda in many other experiments with apples and pears. Indeed so well 

 is the use of this fertilizer gaining recognition for this purpose that large 

 quantities are now used in commercial orchards to deal with many of the 

 difficulties that formerly were considered pollination problems. There 

 are few data showing the influence of quickly available nitrogenous 

 fertilizers on the set of other deciduous fruits, such as peaches, cherries, 

 apricots and grapes. In view of their known influence in apples and 

 pears this subject demands careful investigation. 



Influence of Nitrogen on Size of Fruit. — Since the size the fruit 

 attains is an expression of the plant's vegetative activities it may be 

 supposed that the factors or treatments leading to an increased shoot 



