Fertilizers for Peach Orchards 153 



so what should be applied. His one recourse is to refer 

 to the trees themselves, and the response they make to the 

 application of different kinds of plant-food. 



A soil must contain all the requisite plant-food elements 

 in a form available to the tree, and in suitable amounts, 

 if the tree is to thrive and develop normally. It has already 

 been pointed out that in the practical consideration of the 

 problems the peach-grower is concerned only with three 

 elements, nitrogen, potassium, and phosphorus. These three 

 elements are likely to be deficient for optimum results 

 in the average soil, or if present they are in such chemical 

 combinations that the tree roots cannot take them up. The 

 economical aspects of the problem may now easily be seen. 

 Not only may these three food elements be deficient, but 

 any one or any two of them may be lacking while the others 

 are present in abundance. Yet the absence of one may 

 as effectively limit the growth of the trees and crop pro- 

 duction as if all three elements were lacking. 



A common practice among peach-growers, if they fer- 

 tilize at all, is to apply a complete fertilizer, one containing 

 in quantity all three of the plant-food elements mentioned 

 above. If any one of them is deficient, it is thus supplied 

 in the complete fertilizer, and naturally the trees respond 

 in the manner desired. The grower is pleased with the 

 results and thinks he knows the fertilizer needs of his or- 

 chard. Probably his neighbor peach-grower sees the results 

 and applies the same kind of fertilizer to his trees. He may 

 or may not secure the looked-for results. If he does it is 

 an accident, not the reward of intelligent, well-directed 

 effort on his part. 



The fault with this procedure rests in the fact that a single 

 plant-food only may be lacking and is thus the limiting 



