32 Lessons in Fruit Growmg. 



that incline to grow beyond the lines of symmetry should 

 be pinched. 



Proper summer pruning will greatly reduce the labor of 

 the annual pruning. But summer pruning should be lim- 

 ited to pinching and the rubbing off of incipient shoots, 

 as a rule. The removal of growing shoots after their foli- 

 age is well developed is detrimental to the vigor of the tree, 

 since it removes the leaves that have been formed from re- 

 serve food before they have had time to restore the food 

 they have consumed. 



Branches that are dying from fungous disease, winter 

 injury or other causes, should be removed as soon as dis- 

 covered. 



36, The fertilizing: of orchards. However fertile and 

 well-tilled the land may be at the beginning, the yield of 

 fruit can hardly continue to be profitable unless fertilizing 

 materials are added to the soil in amount corresponding 

 to that removed in the fruit crops. Prof. Roberts has 

 estimated that an average crop of apples removes in round 

 numbers, 11 pounds of nitrogen, nearly one pound of phos- 

 phoric acid and 16 pounds of potash per acre. These esti- 

 mates suggest how important it is to fertilize the apple 

 orchard. We have no similar estimates for pear, plum or 

 cherry orchards, nor for nut trees, but we may rest assured 

 that these crops also remove large quantities of plant food 

 from the soil. 



37. How Shall we know if fertilizers are needed ? The 

 trees will furnish the evidence to some extent. If these 

 are making rapid growth, have deep-green foliage, and 

 mature their wood well, we may infer that their needs are 

 already satisfied. If, on the contrary, they grow slowly 



J Bulletin 103, Cornell University Experiment Station. 



