200 The Commercial Apple Industry 



to require anything but nitrogen. This need is being sup- 

 plied in part by the quite general practice of growing 

 leguminous shade-crops. 



NITBATE OF SODA 



Nitrate of soda as a fertilizer will be more and more 

 / widely used. At first the commercial apple-growers looked 

 r - — askance at this means of maintaining soil fertility, there 

 being a theory that once given nitrate of soda treatment a 

 tree would require continual stimulation. This theory has 

 been disproved, however, and a single application of nitrate 

 of soda may prove beneficial whether later applications are 

 made or not. Continued moderate application at intervals 

 of about two years may prove desirable, however. 



Hood River, Oregon, has been mentioned as one region 

 in which this form of fertilization has proved profitable. 

 The value of nitrate of soda is also recognized in the 

 Ozarks, southern Indiana, western Michigan, in Virginia 

 and particularly in southern Ohio. Wherever the soil 

 is naturally^deficient in nitrogen or where the nitrogen 

 has been exhausted through the planting of other crops, 

 this deficiency can and should be quickly remedied. 



METHODS OF APPLYING FEETILIZEBS 



It may not always pay to apply commercial fertilizers 

 indiscriminately to all trees in an orchard. In other 

 words, one may profitably single out trees which are in need 

 of treatment and omit others. In the average orchard, 

 there will be many trees which are growing vigorously and 

 fruiting well. At the same time, there are likely to be 



