REPORT OF THE CHEMIST. 159 



Standards of Fertility. — It has been remarked that climate and the physical con- 

 dition of a soil are potent factors in determining fertility. To this might be added the 

 statement that fertility (i.e., crop-producing power) is a relative quality, depending to a 

 large extent on the crop grown. The ability of plants to forage for and appropriate 

 their food varies greatly, so that what might be an adequate supply of food for one 

 might prove an insufficiency for another. Buckwheat and wheat will very well illustrate 

 this variation in foraging and assimilating ability. For these reasons chiefly — for of 

 course there are others — it is impossible to establish rigid standards as regards the 

 minimum amounts of plant food that must be present in order that a soil may be classed 

 as economically productive. 



It is not impossible, however, using a large number of analyses of soils, the produc- 

 tive power of which is approximately known, to deduce percentages or limits of 

 plant food, below which, under ordinary circumstances, soils may be considered as 

 deticient or lacking, and above which they may be considered as well supplied or rich 

 in the essential mineral elements. Professor Hilgard, of the California Experiment 

 Station, the highest authority on American soils, considers that less than 0*09 per cent of 

 potash indicates a deficiency in this element, and that the limits of this constituent in 

 good soils range, approximately, from 0*8 to 0"5 per cent in heavy clays, from 0*45 to 

 0-30 per cent, in medium loams, and from 0'3 to 0*1 per cent in sandy loams. 

 Regarding phosphoric acid, he says that 0*2 per cent, is sufficient when associated with 

 a good supply of lime, though it may in certain soils reach or exceed 0"3 per cent. 

 Respecting lime, Hilgard states 0*1 in sandy Icams as the lowest limit for good crops, 

 0'25 per cent, in clay loams, and 0-3 per cent, in heavy clay loams. 



Standards of Fertility in -Canadian Virgin Soils. — Our data indicate that good 

 agricultural soils in Canada possess usually between 0'25 per cent, and 0*5 per cent, 

 potash; less than 0'15 per cent, in our experience, points to the necessity, or at all 

 events to the value, of potassic fertilizers, though with good climatic and soil conditions 

 the limit might be reduced to that suggested by Hilgard. 



The phosphoric acid in Canadian virgin soils of average fertility lies usually 

 between 0*15 and 0"25 per cent. Some good soils contain from 0*25 to 0*3 per cent, 

 and a few exceed the latter figure. The adequacy, or otherwise, of phosphoric acid in a 

 soil would appear to depend largely on the accompanying amount of lime. Increased 

 crop production has usually followed the application of phosphatic fertilizers to soils 

 containing less than 0'15 per cent, phosphoric acid. 



Lime ranks next in importance to potash and phosphoric acid in a consideration of 

 the mineral constituents of plant food. Our experience goes to show, that clay soils 

 containing less than • 5 per cent will have their productiveness increased by a dressing 

 of lime in one or other of its agricultural forms. Peaty soils, and soils generally that 

 are rich in organic matter, are frequently poor in this element. All such have 

 been found to respond to an application of lime, and more particularly so when given in 

 conjunction with potash and phosphoric acid. For these classes of soils, therefore, I 

 deem it advantageous that they should contain at least 1 per cent of lime. 



Richness in nitrogen may be measured to a large degree by the organic or humus 

 content, though the condition or stage of decomposition of this organic matter is an 

 important factor in determining the nitrogen's availability. The larger number of our 

 good soils contain between 0-1 and 0-2 per cent, though many reach 0*5 per cent, and 

 some exceed 1 per cent nitrogen. 



In the following brief review of Canadian virgin soils I have not given any detailed 

 data of their physical condition or composition, for the determinations in our laboratory 

 have been confined simply to the separation of the mineral components into (a) clay and 

 fine sand, and (b) coarse sand, according to the method of Schloesing. The results in 

 this separation, together with remarks on the physical condition or tilth of the soils, 

 have been indicated in general terms in discussing the samples. If it had been possible 

 to have made a more extended physical examination I believe the data would have 

 proved most valuable, for the degree of permeability to water and air, the relative size 

 of the soil particles, compactness, water-holding capacity, etc., are important factors 

 towards establishing a soil's suitability for the various agricultural crops. 



