49 



In our judgment, this has a bearing upon the fact that nitrogen 

 has apparently failed to increase the size of the fruit in our experi- 

 ments. The crop-size was raised so much that full size of the fruit 

 v/as not obtainable. 



It also has an important l^earing upon thinning. It means, in 

 general, that if one thins an apple tree of even moderate size be- 

 fore the number of fruits has reached a critical point, which may be 

 1400 or more, he can hardly expect to modify the size of the re- 

 maining fruit, and the most eft'ect of the thinning will be an actual 

 reduction in total weight of apples at least for that year. Excep- 

 tions to this may appear in varieties of extra large sizes, or in sea- 

 sons or locations that are exceptionally dry. 



It also means that, below the critical or the thinning point, there 

 is opportunity for the other factors to exert their influence. It is 

 here that such factors as fertilizers, cultural methods, moisture-sup- 

 ply, and heredity show their efl:"ects. and they may co-operate in 

 such a way as to materially raise the critical point. This assumes 

 that the variety is properly located in respect to temperature and 

 length of growing season, both of which are factors that mav have 

 an influence on fruit-size. A\'e also may mention here the factors 

 of pollination and number of seeds per fruit, which have been found 

 to afifect fruit-size by Frost and ]\Iuller-Thurgau in Germany. 



A Suggested Fertilizer Formula, with Conditions and Time for 



Application. 



Having thus seen something of the possibilities of fertilizers 

 in orchards, it remains to point out some of the practical applica- 

 tions. In general, we may say that where there is probability that 

 plant food is needed, a good fertilizer is one carrying about 30 pound 

 actual nitrogen, 50 pound actual P2O5, and 25 to 50 pound K2O 



