DIAGNOSING GROWTH CONDITIONS 439 



will tend to check later tree growth and encourage hardening 

 of the wood, making the trees more resistant to fire blight. 



DIAGNOSING GROWTH CONDITIONS AND PRESCRIBING 



TREATMENT 



The various practices to be adopted for each orchard should 

 be determined only after a careful study of tree growth, yields, 

 and environmental conditions. In diagnosing individual or- 

 chards the following factors should be considered: (a) Color of 

 foliage — is it dark green or yellow and sickly looking? (b) 

 Height of tree — is it dwarfed for its age or overgrown? (c) 

 Height and width of tree — is it very tall and narrow, or is it a 

 well-balanced tree? (d) Total growth — is it making a satis- 

 factory growth of new wood each year? {e) Length of ter- 

 minal growth — is the terminal growth 3 inches or 4 feet in 

 length? (/) Is the tree productive — are the fruit spurs numer- 

 ous and vigorous, and are fruit buds formed? 



With this information the physiological condition of the 

 tree can be diagnosed and intelligent treatments prescribed. 



By referring to Chapter IV, *^The Growth of Tree and the 

 Forming of Fruit Buds," the four classes in which plants can 

 be grouped according to the proportion of carbohydrates and 

 nitrogen within their tissues are evident. With the aid of this 

 classification, proper treatments can be prescribed. For in- 

 stance, it is readily apparent that a seven-year-old orchard, 

 on fertile, moist soil, which is being pruned heavily, cultivated 

 thoroughly, and nitrated heavily so that a vigorous growth of 

 wood is produced, but no fruit buds, is in Class II. In this or- 

 chard, less nitrogen should be applied and lighter pruning of 

 the tree should be practiced in order to have proportionately 

 more carbohydrates and less nitrogen in the tissues of the tree. 

 When this is accomplished, the trees would be in Class III, 

 producing only a fair growth and good crops. 



Let us assume another example. If a middle-aged orchard 

 is growing under sod conditions on poor soil with no fertiliza- 



