NEw York AGRICULTURAL EXPERIMENT STATION. 305 
15. The fertilizers applied may not have been thrown away. 
Phosphoric acid, potash and lime will remain in the soil for 
a time at least. 
16. The practical application of the results obtained by this 
experiment is that fruit growers should not apply manures in 
quantity until good evidence has been obtained as to what 
food elements, if any, are wanted in the soil. 
17. As long as trees are making good wood growth and _ pro- 
ducing average crops of well colored fruits, it may be taken 
as granted that they need no additional food from fertilizers. 
If the contrary be true the fruit grower should put in operation 
tests with fertilizers to ascertain what plant foods his soil 
needs. 
THE PROBLEM OF ORCHARD FERTILIZATION. 
Feeding the apple tree is a complex problem. There is a 
series of phenomena in the growth of all orchard trees very 
difficult to deal with in fertilization. Among these are: The 
perennial nature of the plants; the several seasons of growth 
before a crop is borne; the continuous cropping without chance 
for rotation; the facts that tree growth must proceed with fruit 
development, and that a whole season is required for the de- 
velopment of the fruit; the uneven production in different varie- 
ties and on different trees; and the necessity of the storage of 
plant food in bud and branch. These form a set of -conditions 
so different from those encountered in growing general farm 
crops that the practices in fertilizing cereals and herbaceous 
plants do not apply to orchard trees. 
Because of the nature of the plant and of its products, as set 
forth above, it is exceedingly difficult to measure the value of 
fertilizers in an apple orchard, and this complicates the problem 
of their use still more. Thus, who can give the relative values, 
as measures of the worth of manurial treatment, of size of tree, 
number and area of leaves, the fruit and its qualities, and such 
abstract characters as hardiness, productiveness, longevity and 
early bearing? Again, the effects of added or modified plant 
food cannot be seen in an orchard in one season, as with farm 
“crops, but several seasons are required to gauge their influence 
with satisfactory accuracy. 
