88 THE ROYAL SOCIETY OF CANADA 



Discussion of Results: The impregnation is white alkali, the 

 chief constitutent being sodium sulphate. Magnesium sulphate is 

 present in certain of the members, but chlorides are absent, save in 

 traces, throughout the series. In samples D (3'-0 — 5'-0) of two of 

 the groups calcium sulphate is present in considerable amounts. 

 This compound cannot properly be classed as alkali, though it is 

 somewhat open to question if it is altogether inert towards growing 

 vegetation when present in amounts approaching 1 per cent. 



Group 1603. Fair to good growth. The sodium sulphate con- 

 tent is very low and practically uniform to a depth of 3' • 0, the amount 

 in A. B. and C. being less than • 1 per cent, which is usually regarded 

 as negligible^ 



In D (3'-0 — 5'-0) there is a serious increase of this salt, to -641 

 per cent, accompanied by -504 per cent magnesium sulphate. It is 

 doubtful, if at this depth, this alkali markedly alïects the grass crop, 

 the danger of its presence lies in the possibility of its rise by irrigation. 



Group 1602. Meagre and distressed growth. The percentages 

 of sodium sulphate are considerably higher than in the corresponding 

 members of the preceding group, ranging from -117 per cent to -980 

 per cent, the increase being steady and marked from A (O'-O — 0'-5) 

 to D (3'-0-5'0). 



Judging from the sparse and meagre appearance of the crop we 

 might conclude that in this group we closely approach, for Western 

 Rye grass, the limits for tolerance. 



Group 1601. No growth: Soil bare. The percentages of sodium 

 sulphate throughout closely approximate 1-0, the concentration 

 being fairly uniform from the surface to the depth of 5 feet. Notable 

 amounts of magnesium sulphate are present in all the members of 

 this group, save C (l'-5 — 3'-0). 



The alkali impregnation of this group far exceeds the extreme 

 limit of tolerance for ordinary farm crops. 



Native Prairie Grass. 

 Series II. Sec. 9, Tp. 11, R. 25, W. of 3rd Meridian. 



From irrigated field 7 miles south-east of Maple Creek, Sask. 

 The land had been under irrigation for a number of years but had 

 never been cultivated, the native grass being cut and cured as hay. 

 The surface soil was a fairly good sandy loam, the sub-soil of heavier 

 nature, containing a considerable proportion of clay. In the best 



^Less than -2 per cent sodium sulphate, unless concentrated in the first foot, is 

 regarded by most American authorities as not injuriously affecting ordinary farm 

 crops. 



