S4 ROYAL SOCIETY OF CANADA 



fertilizer, they show no signs of diminished productiveness. This 

 experience has been taken by some as an indication that the soil's 

 plant food content is 'as great now as it was twenty-five years ago. A 

 moment's reflection, however, will make clear that this affords no abso- 

 lute proof that the soil is not poorer than when first cultivated; it 

 simply points to the presence to-day of a sufficiency ."><: available plant 

 food to produce, under the condition of culture employed, a maximum 

 crop. That there has been in such soils a real decrease in the ele- 

 ments of plant food, we have recently been able to demonstrate by 

 analyses of certain samples of soils representative of virgin and culti- 

 vated lands collected in the jNTortli-west Territories at Indian Head. In 

 the case of the cultivated soil examined we are very fortunate in having 

 a very complete record, since the prairie was first broken, twenty-two 

 years ago, of the cropping and the cultural methods that have been 

 employed. Mr, Angus MacKay, Superintendent of the Experimental 

 Farm, Indian Head, N.W.T., who collected the samples, has kindly fur- 

 nished us with the following data respecting the cultivated soil : — 



History of Cultivated Soil. 



1883 Wheat. 1894 : . . . .Fallow. 



1884 Wheat. 1895 Oats. 



1885 Wheat. 1896.... ....Fallow. 



1886 Barley. 1897 Barley. 



1887 Wheat. 1898 Fallow. 



1888 Fallow. 1899 Wheat. 



1889 Oats. 1900 Fallow. 



1890 Fallow. 1901 Oats. 



1891 Barley. 1902 Fallow. 



1892 Fallow. 1903 Barley. 



1893 Wheat. 1904 Fallow. 



The above, summarized, shows 6 crops of wheat, 4 of barley, and 

 3 of oats, with fallows between each crop since 1(SS7. No manure has 

 ever been applied. 



The sample of virgin soil was taken from an adjacent area that 

 had 'never been cultivated, the point of collection being about 120 feet 

 from where the cultivated soil samples were taken. There is every 

 reason to suppose that the soil over the whole area was originally of 

 an extremely uniform character and that 'the cultivated soil had at the 

 outset 'the same nitrogen content as the area that has remained un- 

 touched. 



The samples, both from the cultivated and virgin areas, were taken 

 so that they miglit represent the soil for tiic first 4 and 8 inches respect- 



