52 MANURES FOR FRUIT TREES 



considerably in each tree or plant. The roots 

 appear to have, more or less, a selective action 

 on the mineral constituents of the soil — and these 

 mineral or inorganic substances are of the greatest 

 importance to plant growth. They are necessary 

 to the formation and the existence of the vegetable 

 productions in which they are found. It is true 

 that certain mineral substances are common to 

 most trees, yet their amount and relative pro- 

 portion vary with each tree; hence, some are 

 called potash plants, others lime plants, etc., ac- 

 cording to the prevailing constituent of their ashes. 



Since each tree requires a certain kind and 

 definite quantity of mineral matter for its growth, 

 it is a sine qud non that unless the soil is capable 

 of furnishing these materials in sufficient quantity 

 and in suitable form, the tree will not flourish 

 upon it, and if the soil is entirely destitute of 

 the particular mineral substance or substances 

 required by it, the tree refuses to grow, or at 

 least to come to perfection. 



If an apple tree does not bear fruit, or the 

 fruit is meagre, the cultivator should look to 

 the composition of the soil. The same remark 

 applies to other trees — every tree contains some 

 principle peculiar to itself, which gives rise to 

 the distinguishing characteristics of its produce— 



