Methods of Use of Fertilizers 203 



that this may be accomplished, they must be supplied 

 with an abundance of available plant-food, and since 

 nitrogen is the one element which more than any other 

 encourages and stimulates leaf and stem growth, its use is 

 especially beneficial to all of these crops. They must not 

 lack for this element in any period of their growth, though, 

 of course, a sufficiency of minerals must be supplied in 

 order that the nitrogen may be properly utilized. Because 

 of their high commercial value, the quantity of plant-food 

 applied may be greatly in excess of that for any other of 

 the groups, and profits, as a rule, are measured by this 

 excess rather than by the proportion of the elements. 



Fruit crops. 



Another distinct class of crops, though differing materi- 

 ally in their individual characteristics, as well as in their 

 tune and period of growth, are the fruits. These differ 

 from most other crops, in that a longer season of prepara- 

 tion is required, in which the growth may be so directed 

 as to prepare the plant or tree for the proper development 

 of a different kind of product, namely, fruit, as distinct 

 from grain or seed in the cereals, or succulence in the 

 vegetable crops. The fruit differs in its characteristics 

 from the ordinary farm crops, in that its growth and de- 

 velopment require a little different treatment, since it is 

 necessary that there shall be a constant transfer of food 

 from the tree to the fruit throughout the entire growing 

 season. The growth of each succeeding year of tree and 

 fruit is dependent, not altogether upon the food acquired 

 during the year, but as well upon that acquired in the 

 previous year, and which has been stored up in bud and 

 branches. A knowledge of the habits of growth, the period 

 of growth and the object of the growth of this class is, 



