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more conspicuous to the discerning fruit grower and nothing more 

 interesting than the great variabiHty of varieties in their response 

 to the influence of environment, for we have come to think of a 

 variety, not as an entity in itself but of a plastic thing which is the 

 product of the influences under which it is grown. 



It is worth while in this connection to ask : ''What are the 

 influences which affect the behavior of a variety, making it valuable 

 in one place and perhaps worthless in some other?" In other words, 

 what constitutes the environment which determines whether a va- 

 riety inherently meritorious, is good or bad in a particular place? 

 In the last analysis, the two great determinants or limiting factors 

 for all plant life, and to a considerable extent also of animal life, 

 are temperature and moisture. In the case of cultivated plants 

 we must also add the soil factor and methods of culture. It may be 

 doctrinal heresy to admit it but personally, I put less stress within 

 certain rather broad limits upon the soil factor than upon any of 

 the others that are really dominant in any particular. And for 

 the tree fruits I place greater importance upon the character of the 

 subsoil than upon the surface soil. 



To give satisfactory results with any variety of fruit, a soil 

 must have certain characteristics. It must contain sufficient plant 

 food in an available form to induce a good vigorous growth of 

 wood. In other words, it must be sufficiently fertile for the end 

 in view. To this end it must contain humus or decaying vegetable 

 matter in considerable quantities. A soil deficient in humus, more 

 or less broadly speaking, is an unproductive or non- fertile soil. 

 It must be a soil that is sufficiently porous and light to permit water 

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

 easily penetrated by the roots. These last two tenets apply par- 

 ticularly 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 re- 

 quired 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. Given 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, I want to 

 mention one other feature. It may be that each fruit variety re- 

 quires for maximum results its own particular 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: (3.) It serves as a means of holding the tree upright and in 

 place; fb) 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. 



