Damon Boynton 281 



TABLE II 



Girth Increase and Shoot Growth in a New York Mcintosh Apple Orchard 

 under 3 Levels of Nitrogen Fertilization 



*Least difference for statistical significance at the odds indicated. 



fTwenty shoots per tree were measured at random after terminal growth had stopped in each 

 year. 



correlated with the length of the shoot, as is indicated in Table III. Not 

 only were there the most leaves and largest leaves per shoot on the 

 highest nitrogen trees, but the leaves contained the most chlorophyll 

 and the two-year-old growth produced the most branches and spurs. 

 Thus, the failure of the second increment in nitrogen to cause an aver- 

 age increase in yield was not due to a lack of vegetative response to 

 the nitrogen, but resulted from failure of the vegetative response to be 

 translated into yield response as it was in the case of the first increment. 

 Figure 1 shows that the annual yield fluctuations in this orchard 

 were far greater than the differences associated with nitrogen level in 

 any one year. These fluctuations from year to year were due largely 



TABLE III 



Correlations Between Shoot Length, Leaf Numbers, and Leaf Area for 120 

 Mcintosh Apple Shoots from 2 Nitrogen Fertilizer Experiments, 1948 



Correlation r 



Shoot length X number of leaves 0.918* 



Shoot length X total area of leaves > 2 sq. in. 0.886* 



Shoot length X average area per leaf of leaves > 2 sq. in. °-5 2 5 



* 



"■Significant at i per cent point or beyond. 



