Orchard Fruits and Berries 315 



An experiment 1 bearing upon this point is very instruc- 

 tive, as indicating the need of manures for fruit trees, not 

 only in reference to the amount removed, but also in refer- 

 ence to the proportions of the essential constituents re- 

 quired. This study shows that the plant-food contained 

 in 20 crops of apples, of 15 bushels to the tree, and 35 

 trees to the acre, and in the leaves for the same period, 

 amounts, in round numbers, to 1337 pounds of nitrogen, 

 310 of phosphoric acid and 1895 of potash. These 

 amounts of plant-food are compared with the amounts that 

 would be removed by 20 years' continuous cropping with 

 wheat, assuming an average yield of 15 bushels of wheat 

 to the acre, and 7 pounds of straw to 3 bushels of grain ; 

 viz., 660 pounds of nitrogen, 211 of phosphoric acid and 

 324 of potash. By this comparison it is shown that the 

 20 crops of apples remove more than twice as much nitro- 

 gen, half as much again of phosphoric acid and nearly 

 three times as much potash as the 20 crops of wheat. 



These results are valuable in indicating the rate of soil 

 exhaustion by apple-growing. It is to be remembered, 

 however, that the larger root development of the tree 

 would enable it to draw its nourishment from a larger 

 area of soil than is the case with wheat, and thus probably 

 permit of normal growth for a longer period. 



Too many are satisfied with short crops of medium fruit, 

 with off-years and with short-lived trees, largely because 

 they do not know that all of these conditions may be im- 

 proved by a proper feeding of the tree, and that such feed- 

 ing will usually result in a very largely increased profit. 



Statistics gathered in the state of New Jersey 2 show that 



1 Cornell Exp. Sta., Bulletin No. 103, "Soil Depletion in 

 Respect to the Care of Fruit Trees." 



2 Bulletin No. 119, New Jersey Experiment Station. 



