REPORT OF THE CHEMIST. 157 



per aero may be used if wood ashes are not readily obtainable. Potash is required 

 especially for leafy crops. 



Superphosphate, for furnishing soluble phosphoric acid, can be used to advantage 

 for cereals, turnips, &c., at from 200 to 400 pounds per acre. 



To induce vigorous growth in the early part of the season, 100 pounds of Nitrate 

 of Soda per acre can be used as a top dressing, applied in, say two portions at intervals 

 of 3 or 4 weeks after the appearance of the crop. 



THE COMPOSITION OF CERTAIN CANADIAN VIRGIN SOILS.* 



Of the many investigations carried on by the Chemical Division of the Dominion 

 Experimental Farms during the past ten years, not the least in scientific interest nor in 

 agricultural value have been those which have had for their object the determination of 

 the amounts of plant food in certain typical and virgin soils of the Dominion. The 

 data are not a,s yet voluminous, for this work is one that consumes much time, and 

 other and more pressing demands have only permitted an intermittent attention to it ; 

 nevertheless we have been able to place on record results which go far towards indicating 

 the character of many soils representative of large untilled, or, at all events, but partially 

 settled districts in Canada. 



In all, we have submitted to complete analysis about ninety samples. These 

 comprise surface and sub-soils taken from the Atlantic to the Pacific in the various 

 provinces of the Dominion, and, to the best of our knowledge, from areas which had 

 never been manured or cropped. 



It is not my purpose to present in this paper all the data obtained, nor to attempt 

 an interpretation of all the figures, chemical and physical, that have resulted from this 

 work, for such would scarcely be possible. My intention rather is to bring before you 

 the percentage composition of these soils as regards certain of the more important 

 elements of feriility, and to draw such deductions as to relative richness or deficiency 

 in plant food as may seem warranted when comparing the figures with those obtained 

 from the examination of soils in other countries. 



The Value of Ordinary Soil Analysis. — The exact value of a chemical analysis 

 towards ascertaining the fertility of a soil is a question that probably will always be 

 open to discussion, and doubtless all present are aware that no problem in agricultural 

 science has excited more interest or been debated with greater warmth. We are obliged 

 to confess that a knowledge of the amounts of nitrogen, potash, phosphoric acid, (fee, as 

 estimated by our present methods of determining " total " or maximum amounts of plant 

 food constituents by strong solvents, is not in itself sufficient for making a diagnosis as 

 to the crop-producing power of a soil. Why this is so, will be apparent upon reflection. 

 In the first place, hydrochloric acid of the strength employed in the analysis dissolves 

 from the soil the mineral constituents in much larger amounts than are present in an 

 immediately available condition ; and secondly, there are factors other than the amount 

 of plant food present that are equally important in determining a soil's fertility. The 

 physical condition of the soil, including retentivity of moisture, capillarity, permeability, 

 (fee, the meteorologic conditions, including rainfall, mean temperature, sunshine, <fec., must 

 all be carefully considered in conjunction with the analytical figures when endeavouring 

 to interpret the latter with a view of ascertaining the soil's probable crop-producing 

 ability. The case is very similar to that of water analysis, in which it is universally 

 held that all possible information respecting the source and its environment must be in 

 the possession of the chemist before he can intelligibly and correctly give judgment 

 from his figures upon the quality of the water under examination. 



* Read before the Chemical Section of the British Association for the Advancement of Science, at 

 Toronto, August, 1897. 



