362 ANNUAL REPORT OF THE Ofif. Doc 



percolate through it readily. Such a soil as this will also be easily 

 penetrated by the roots. These last two tenets apply particularly to 

 the subsoil. 



I place so much importance upon the subsoil because it is that 

 very largely in which the roots are imbedded. It is the subsoil 

 very largely that acts as a reservoir for the moisture supply required 

 by the trees. If it is too compact, and hard, the moisture does not 

 pass through it with sufficient freedom, either up or down, and 

 the roots find too much obstruction to readily penetrate it for food 

 and moisture, (liven these characteristics and a soil so far as the 

 soil factor itself is concerned may be looked upon as having the 

 requisites for fruit growing. 



And now that I am referring to this soil factor, 1 want to men- 

 tion one other feature. It may be that each fruit variety requires 

 for maximum results its own i^articular type of soil but I question 

 if we can recognize this from any practical standpoint, on the basis 

 of the soil itself, to the extent that is sometimes assumed. The soil 

 performs three functions in relation to a tree growing in it: (a) It 

 serves as a means of holding the tree upright and in place; (b) it 

 is the source of mineral plant food either contained in it naturally 

 or applied by the act of man; (c) it serves as the direct source from 

 which the tree gets its supply of moisture. A soil may be too light 

 in one extreme or too heavy in the opposite extreme, as we ordinarily 

 use these terms, to come within the broad limits implied in the 

 outset. 



There is a most intimate relationship between the moisture supply 

 and the mineral food supply because the latter is available for the 

 use of the tree only as it goes into solution in the water or moisture 

 that is in the soil. 



Again, as soils of different types and in different conditions may 

 have different temperatures, there may be a temperature factor 

 involved in the relation of a particular soil to the behavior of a 

 variety. 



Now suppose we think we have found for a particular variety 

 the exact type of soil both with regard to its physical condition, its 

 relation to the supply of plant food, moisture and temperature for 

 maximum results in every respect. Very well ! But the very next 

 season after we have reached our conclusions it may be abnormally 

 rainy, or abnormally dry or excessively hot or cold as the case 

 may be. We at once have every factor in our scheme thrown out 

 of adjustment and the relationships of food supply, moisture and 

 temperature are entirely disturbed. As a result we find our chosen 

 variety giving maximum results perhaps on an entirely different 

 type of soil from the one we have previously had under considera- 

 tion, even though that type remains unchanged as a type. 



Then, too, we have a variety growing on a particular type of 

 soil and giving certain results under some definite system of soil 

 culture and orchard management. We change our system of man- 

 agement and totally different results follow. Yet the soil, as a 

 type remains the same. The thing I want to im])ress upon you 

 is simply this: Granting for the sake of the argument the possi- 

 bility of there being varietal preferences as to soil types within the 

 broad limitations already specified, the soil influences so far as 



