240 .The Canadian Horticulturisi. 



HOW THE APPLE TREE GROWS— H. 



ET us consider what an acre of apple trees will probably 

 take from the soil in producing the woody frame work, also 

 the fertilizing constituents needed to produce the annual 

 crop of fruit and foliage. Suppose we estimate the weight 

 of the trunk and branches of an average tree at 1,000 

 pounds, which is only a rough guess, and that we have 70 

 of such trees on an acre. These, on the basis of the calcu- 

 V ▼ lation we have given, will have taken from the soil to pro- 



duce their wood growth about 2 to 3 pounds each of nitrogen, or 140 to 210 

 pounds in all, and not more than 10 ounces each of potash and phosphoric 

 acid, or about 44 pounds of each of these elements for the full acre. As this is 

 the entire consumption of these important constituents of the soil during the 

 whole period of the life thus far of the acre of orchard, for its wood growth, this 

 small proportion can be easily supplied by the poorest soil without severely 

 taxing its capacity.' It is, indeed, wonderful that so great a growth can be 

 brought about with so small a consumption of fertilizing material. This may 

 well serve to lessen the astonishment one often feels at seeing a thrifty and 

 vigorous forest tree growing in the crevice of a rock where it would seem that 

 but little .nourishment could possibly be had from the small quantity of soil 

 available to its roots. 



As the leaves of the apple tree are always allowed to fall on the ground, 

 where they gradually decay and are returned to the soil, the full quantity of 

 fertilizing constituents they take from the land need not be considered here. 

 It will be a fairly liberal estimate if we take half the quantity as requiring to be 

 replaced. I know of no estimate which would guide one in ascertaining the 

 approximate weight of leaves on a full-sized apple tree, but supposing we guess 

 it at 100 pounds, we shaM then consider the fertilizing ingredients which entei 

 into the composition of 50 pounds of apple leaves for each of the 70 trees. 

 These taken at their maturity will be found to contain about 31^ pounds of 

 nitrogen, 14 pounds of potash, and about 7 pounds of phosphoric acid. 



Supposing the crop to average annually two barrels per tree, each barrel 

 containing 120 pounds of apples, we should have for the seventy trees an annual 

 production of 16,800 pounds, which would take from the soil yearly about 19 

 pounds of nitrogen, S}4 pounds of potash, and less than 1)4 pounds of phos- 

 phoric acid. Adding to the fertilizing constituents required for the fruit those 

 necessary for the production of half the annual crop of leaves, we have : 



Lbs. 



Leaves, nitrogen 31^ 



Fruit, I. , 19 



Total 50^ 



