141 



]P^RT TV. 



g^HE COMPOSITION OF APPLE TEEE LEAVES. 



At the Dominion Fruit Growers' Convention held in Ottawa, February, 

 1890, I had the honour of reading the following paper, which is the first of 

 a series on the chemistry of the apple. As time allows, the fruit and the 

 old and young wood of the tree will be analj^sed. From the data thus 

 amassed it is confidently hoped that we shall be able to ascertain with more or 

 less accuracy the nature and amount of those fertilizing elements withdrawn from 

 the soil by the apple tree in bearing. This will be the first step towards a more 

 rational mode of applying fertilizers to orchards. 



" THE COMPOSITION OP APPLE TREE LEAVES. 



"Agricultural chemists throughout the world are, and have been for some 

 years, directing their attention towards the solution of questioiis concerning the 

 growth and bringing to perfection of plants and animals which serve for the use of 

 man. With regard to plants — and by that term I include all farm crops — analyses 

 have been made of all their parts, so that their composition is, to-day, pretty well 

 known. 



'* Field experiments and experiments in water culture — in which the vai-ious 

 salts required by the plants are dissolved in water — have also been made, enabling 

 us, at the present time, to state definitely what special fertilizing constituents are 

 valuable for the growth of certain crops, what classes of soil are most suited to 

 cereals, the leguminous plants, and so on. 



" But as yet it appears that little has been done in this direction for the fniit- 

 growers, and the reason for this is not difficult to find. In all experiments of ihis 

 nature it is necessary to weigh and analyse an aliquot part of the final product of 

 vegetable growth in order to arrive at the amount of plant food absorbed from the 

 soil and other sources, and in this way ascertain the extent to which the soil has been 

 exhausted and the special inorganic and organic elements which enter into the com- 

 position of plants tissues. In the case of farm crops, which are reaped annually, this 

 is comparatively an easy task, but it is obvious that in the case of fruit trees — both 

 small and large — this of necessity cannot easily be done. As, however, it is as highly 

 important to the fruit-growers to know what kind of food and what class of soils 

 are best suited to produce the largest amount of fruit as it is to the farmer to be in 

 possession of such information respecting his crop, it is but the duty of those engaged 

 in working out these problems to direct their study, as far as in their power lies, 

 towards the solution of such difficult questions. 



" It was with a view of throwing some light upon this abstruse subject, of pro- 

 posing some rational mode in the application of fertilizers to orchards, that the 

 work included in this paper was undertaken. 



"Now, it must not be thought that even if we knew the exact composition of all 

 the parts of the tree (and as long as the fruit is hanging it remains part of the tree), 

 and the total weight of those component parts, and had also a knowledge of the 

 composition of the soil in which the tree was growing, that the whole question would 

 be settled. Until a few years ago it was thought that such data were sufficient to 

 guide the agriculturist in manuring certain fields for certain crops, but later facts, 

 evolved by patient experiments, conducted most carefully over many years, have 

 now proved this theory fallacious. I might illustrate this by reference to the cereals 

 and leguminosse. The former contain but half the nitrogen of the latter, yet no1>- 

 withstanding this fact, and all that it seems to imply, it is found that the application 



