310 Fertilizers 



THE SPECIFIC FUNCTIONS OF THE ESSENTIAL FERTILIZING 

 CONSTITUENTS 



It must be admitted, however, that the general principles 

 of manuring, as applied to farm crops, also apply to fruit 

 and berry crops ; that is, the essential manurial constitu- 

 ents must be the same. 



"A fruit tree will not make normal growth in a soil 

 destitute of nitrogen. That nitrogen encourages leaf 

 growth is a recognized fact, and since trees grow by means 

 of both leaf and root, its presence is required in the soil in 

 order to promote the growth and extend the life of the 

 tree. It is very evident, too, that potash is an essential 

 constituent in the growth of fruits, not only because it 

 constitutes a large proportion of the ash of the wood of 

 the apple, pear, cheery and plum, and more than 50 per 

 cent of the ash of fruit, but because it forms the base of 

 the well-known fruit acids. Phosphoric acid is also very 

 essential in order to nourish a tree properly, as well as to 

 insure proper ripening, though it is apparent from such 

 investigations as have been made that this constituent is 

 relatively of less importance than for the cereals." 



It is also a matter of common observation that in the 

 production of stone-fruits, particularly, lime is an impor- 

 tant constituent. Its functions seem to be to strengthen 

 the stems and woody portion of the tree, to shorten the 

 period of growth, and to hasten the time of ripening. 

 Fruit trees growing on soils rich in lime show a stocky, 

 steady, vigorous growth, and the fruit ripens well, while 

 those on soils which contain but little lime, particularly 

 the clays, appear to have an extended period of growth, 

 the result of which is that the wood does not mature and 

 the fruit does not ripen properly. 



