204 The Principles of Fruit-growing. 



"The total amount of nitrogen, exclusive of that 

 used in the growth of the trees, is 1,336.8 pounds, 

 of phosphoric acid 310 pounds, and of potash 1,895.4 

 pounds. To restore the potash alone, as above, and 

 that used by the growth of the tree, it would re- 

 quire 21.69 tons of high-grade ashes containing 5 

 per cent of potash. To restore the nitrogen as 

 above, would require 16.19 tons per acre of a com- 

 mercial fertilizer containing 5 per cent of nitrogen. 



"How much of this plant-food is usually fur- 

 nished to the orchard by leguminous plants and by 

 feeding supplementary foods to animals which graze 

 upon it, and how much by the fallen leaves and 

 apples which are not blown or carried off, cannot 

 be told. 



"While some of the computations and conclusions 

 are based on estimates, yet it is believed that the 

 tables represent average conditions, and need only 

 the good judgment of the observant reader to make 

 them apply to his individual case with such degree 

 of accuracy as to give valuable aid in the care and 

 feeding of orchards. 



"Many old orchards have not only been making 

 these large demands on the soil for the last twenty 

 years, but in many instances the land has been used 

 for the production of hay or grain, or more fre- 

 quently for the growing of lambs or pigs, with 

 little or no supplementary food. The grazing of 

 orchards, especially with growing animals without 

 extra food, is as certain to deplete the land as grain 

 raising, though the soil robbery is not so rapid. 



