624 Agricultural Experiment Station, Ithaca, N. Y. 



Table YII. 



Apples. Leaves, 



lbs. lbs. Value. 



Nitrogen 332.40 304.50 $95 54 



Pbospboric acid 5i5.50 84. 7 67 



Potash 485.70 294. 35 09 



Total value $138 30 



The following table gives the total plant food in leaves and fruit 

 and its value for a single acre (nitrogen, phosphoric acid and potash 

 being computed in all cases at 15, 7 and -i.S cents per pound respect- 

 ively) for the whole bearing period of twenty years, from the time 

 the tree was 13 years old from setting until it was 33 years old : 



Table YIII. 



Apples. Leaves, 



lbs. lbs. Value. 



Nitrogen 498.60 456.75 $143 30 



Phosphoric acid 38.25 126. 1150 



Potash 728.55 441. 52 63 



Total value $207 45 



While the above results are reached by assuming a given amount 

 of apples and leaves per year in a bearing orchard, and while the 

 facts in any given case at any given time may vary widely, yet it is 

 believed that they are valuable as they furnish a means of measur- 

 ing in any given case, with a great degree of accuracy, the amount 

 of soil exhaustion. 



Table Y. shows that 5 bushels of apples remove in round num- 

 bers 11 pounds of nitrogen, nearly 1 pound of phosphoric acid and 

 16 pounds of potash, and that the leaves of a tree large enough to 

 produce the apples would contain 10 pounds of nitrogen, nearly 3 

 pounds of phosphoric acid and 10 pounds of potash, or a total of 

 21 pounds nitrogen, 3 pounds phosphoric acid, 26 pounds potash. 



It will be seen how easily the other tables can be used to deter- 

 mine approximately the amount and kind of plant food used by 

 apple trees in any given case. 



In a given year, a mature tree might produce as many apples as 

 the amount assumed and in another year fail to produce any, yet a 

 computation could be made from the data given which would throw 

 much light on the vexed question of orchard soil exhaustion. 



