Mineral Nutrients 157 



AMOUNTS OF NUTRIENTS REMOVED PER ACRE BY THE FRUIT l ALONE 



Assuming that the leaves, dead twigs, etc., are annually 

 returned to the soil, fruits are ordinarily less exhausting 

 than field crops. In this connection it is entirely imma- 

 terial that a bushel of oats of the same variety, or a barrel 

 of Baldwins, will not always contain the same amounts of 

 nitrogen, phosphoric acid, and potash. Other analyses, 

 therefore, will not accord in detail with those given. The 

 fact that these crops are not exhausting is important in con- 

 templating the maintenance of fertility in intensive fruit 

 production. It would seem that in fruit production it 

 may easily be possible to realize a permanent system of 

 agriculture. 



85. Amount of nutrients in soils. Fertility is a matter 

 so complex dependent upon such a variety of factors 

 that a chemical analysis is important in two respects, 

 chiefly: (1) to indicate the total amounts of plant food, 

 for the time available or unavailable, and (2) to point out 

 unbalanced conditions, or to suggest lines of treatment. 

 Ultimately, experiments with the plant are invariably 



1 Ibid., p. 370. 



