Section III, 1921 [61] Trans. R.S.C. 



The Vertical Movement of ''Alkali'^ under Irrigation in Heavy Clay Soils 



By Frank T. Shutt, D.Sc, and Alice H. Burwash, B.A. 



(Read May Meeting, 1921) 



In the examination of the soils of Southern Alberta — a work 

 undertaken to obtain the chemical and physical data necessary to a 

 satisfactory classification of the areas involved into irrigable and non- 

 irrigable tracts —several important problems have arisen, the solution 

 of which would have a distinct and direct bearing on the decision 

 respecting the advisability of releasing the land for cultivation under 

 irrigation. 



One of the most urgent of these problems as affecting the possi- 

 bility of rise of alkali under irrigation is the determination, upon the 

 application of water, of the movement, its direction and rate, of 

 alkali in a heavy clay subsoil, the surface soil to a depth of say 15" 

 to 18" being essentially free from soluble saline matter. An oppor- 

 tunity to study this question and collate useful data thereon was 

 offered by the soil conditions existing over certain large areas on the 

 C.P.R. Demonstration Farm at Tilley, Sec. 24, Tp. 17, Rge. 13, West 

 of the 4th Meridian, Alberta. Speaking broadly, the conditions 

 referred to are a heavy, stiff, almost impervious, clay loam, free from 

 all save traces of saline matter, of good quality but difficult to work 

 and drain. The surface soil overlies a subsoil of an extremely heavy 

 and impervious character which carries a notable saline content. In 

 the zone 0'.5 to 1'.5 the alkali reaches a notable but not excessive 

 concentration and materially increases to a depth of 5 feet, marking 

 the lowest point at which samples were taken. 



The "alkali" found is essentially sodium sulphate, with small 

 percentages of magnesium sulphate, the whole being associated with 

 comparatively large amounts of calcium sulphate. Chlorides and 

 carbonates of the alkalies are practically absent. 



For the purpose of this study soil groups consisting of four 

 members each, viz., A-0'.0-0'.5, B-0'.5-l'.5, C-l'.5-3'.0 and 

 D. — B'.O — 5'.0 were taken by means of a soil auger. Groups were 

 collected in two plots, under various croppings, the first series being 

 taken in 1916, irrigation water having been applied for the first time 

 in 1915. Successive group samples from the two points selected were 

 obtained in 1917, 1918, 1919 and 1920 and their saline content deter- 



