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 ease 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, expecially with growing animals without 
extra food, is as certain to deplete the land as grain 
raising, though the soil robbery is not so rapid. 
