FRUITS 247 



and of poor keeping quality. If used in great excess, 

 a serious disease known as " die back " will be in- 

 duced, from the effect of which the tree may never 

 completely recover. The source of the nitrogen used 

 seems, too, to be a factor of importance. Stable ma- 

 nure should never be used in the orange orchard, and 

 other organic sources of nitrogen, like cotton-seed 

 meal and dried blood, are more dangerous than the 

 mineral salts, like nitrate of soda and sulphate of 

 ammonia. Even leguminous cover crops must be 

 used with caution as their continued use in connec- 

 tion with other fertilizers has been known to occasion 

 "die back." No hard and fast rule can be given 

 governing the use of nitrogen in the orange orchard. 

 The trees should be carefully Avatched and should 

 be fed with it according to their evident needs. The 

 amount to use will vary from time to time with the 

 condition of the trees and of the weather. More 

 can be used safely during the winter and in dry sea- 

 sons than during wet midsummer weather, but it is 

 always the part of safety to under rather than over 

 feed with this substance. The total amount of fer- 

 tilizer used by the Florida growers is very large. It 

 may reach as much as fifty or even a hundred 

 pounds per tree in the case of large old trees that are 

 in heavy bearing, but young trees during the first 

 year do not receive more than from one to five 

 pounds. It is best to divide the amount to be used 

 for the year into at least two applications, and some 

 growers prefer as many as three or four, especially 

 for the nitrogenous part of the fertilizer. Expe- 

 rience with fertilizers in the islands is not yet very 



