MANURES 89 



peculiarities of the roots themselves, would affect the case in the 

 same way as the distribution of the roots in the ground, and the 

 extent of any action of this sort would depend on the relation 

 of the factors concerned to the requirements of the plant. 



With all these elements of uncertainty it is impossible to dog- 

 matise as to the effect of manures on fruit trees, and no conclu- 

 sions based on what has been established respecting farm crops 

 can with safety be applied to the case of trees. This is evident 

 from the mere fact that forest trees may continually be found 

 flourishing on land which is too poor for ordinary agricultural 

 crops. Even if a crop of apples, including the wood formed by 

 the trees, removes as much material from the soil as does a crop 

 of wheat, this material would generally be drawn from a much 

 wider area, and there should be nothing to justify surprise if it 

 were found that the food-supply were not materially affected by 

 the removal of ten or twenty annual crops, or that manure applied 

 to the surface had had no appreciable effect during that period. 

 That the process of drawing on the supplies without replenishing 

 them can be continued indefinitely is, of course, out of the 

 question; but the total store of food-material in any ordinary 

 soil is so enormous, and we are yet so ignorant of the rate at which 

 it may be brought into the available condition under various 

 circumstances, that it is impossible to set any limit to the lapse 

 of time occurring before a tree would begin to suffer from exhaus- 

 tion. There are thousands of orchards in England where apples 

 have been grown for centuries with little or no manuring, and in 

 which young trees will still flourish when planted under proper 

 conditions as to light and the removal of grass. 



The question of manuring is one on which the grower is not 

 likely to be influenced by considerations of the possible exhaustion 

 of the soil in future generations; the practical problem for his 

 consideration is whether manuring will repay him, either now or 

 within a reasonable period. 



The results obtained at Ridgmont during twenty-two years 

 lead to the conclusion that the apple trees which have been dressed 

 every year throughout that period with various dressings of arti- 

 ficial or natural manure have shown no appreciable advantage 

 over similar trees which received no dressing whatever. Whilst 

 this, however, has been the case with dwarf and standard apple 

 trees, and also with mixed plantations of apples, pears and plums, 

 the reverse has proved to be the case with bush fruits, such as 

 currants, gooseberries and raspberries : those which were left 

 unmanured have been practically exterminated, whilst those 



