FOOD FOR PLANTS 143 



and fertilization are all interrelated in their effects 

 on tree growth and yield, and are big problems to the 

 fruit grower. 



Nitrate of Soda enables the trees to retain their 

 leaves for a longer period and this permits the tree 

 to continue its storing of food for its spring work. 

 Nitrate of Soda applied in the spring, just as the 

 buds begin to swell, gives the tree Nitrogen immedi- 

 ately, which enables it also to use the food reserves 

 it has stored up. This strong application increases 

 the percentage of bloom set. 



Nitrate of Soda thus used early in the spring, just 

 at the time the tree needs it, will develop strong 

 blooms. It can be used when the ground is cold, 

 as it does not require the action of soil bacteria to 

 make it available, as do other forms of nitrogen. 



In cold climates, where early heavy frosts occur, 

 there is some danger in making too late spring appli- 

 cations since so used Nitrate is apt to prolong the 

 growth of the tree and an early autumn frost may 

 injure the immature fruit buds or wood prior to the 

 time of their settling down for the winter. 



Trees which have been kept in a healthy growing 

 condition by the proper use of Nitrate of Soda are 

 much more resistant to disease. 



The terminal growth which trees make is usually 

 a good indication as to whether they are properly 

 nourished. Young trees, before they come into full 

 bearing, should make a yearly terminal growth of 

 from twelve to eighteen inches. Mature trees should 

 make a growth of from seven to eleven inches. 



The color of the leaves is another indication of the 

 condition of the tree. If the leaves are not a good 



