190 The Commercial Apple Industry 



These investigators found that by dividing plants into 

 three groups a certain definite relation is brought out 

 between the nitrogen and carbohydrates present in the 

 different groups. These groups are. divided as follows : 



Group 1. Those plants which seem to be extremely vig- 

 orous but rarely bloom, and if they do bloom, set but little 

 fruit. 



Group 2. Those plants which make a very fair growth 

 and seem to be in good vigor, bear very abundantly and 

 produce a large number of clusters, the blossoms of which 

 readily set fruit. 



Group 3. Those plants which are less vigorous than the 

 second group, bloom profusely, but set fruit very sparingly. 



A chemical analysis of the plants in these groups shows 

 that: (1) those of the first group always contain an abund- 

 ance of moisture and nitrogenous compounds; (2) those 

 in the second contain a relatively smaller amount of nitro- 

 genous compound as compared with the carbohydrates 

 (sugars and starches) ; (3) the plants of the third, group 

 contain still less of the nitrates and proportionately much 

 more of the carbohydrates than the second group. It is 

 shown rather conclusively from these experiments that 

 there must be a certain mathematical relation between the 

 nitrates and the carbohydrates in order to secure the best 

 results. 



The results of these studies directly apply to the apple. 

 Examples of the first group are commonly found in trees 

 from one to seven years of age which have a great abund- 

 ance of nitrogen as compared with the amount of carbo- 

 hydrates, such a condition being encouraged by intensive 

 tillage, severe heading of trees or use of nitrogenous fertil- 

 izers. As a result, considerable wood growth but little 



