Section III, 1922 [227] Trans. R.S.C. 



The Vertical Movement of Alkali under Irrigation in Heavy Clay Soils 



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



(Read May 18th, 1922) 



Irrigation has made possible the successful, profitable culti- 

 vation of large areas hitherto unproductive owing to a scanty rain- 

 fall. In arid and semi-arid districts irrigation has reclaimed and 

 rendered fertile hundreds of thousands of acres otherwise barren 

 and unprofitable for agriculture. But it is a practice which to be 

 safely applied demands a full knowledge of soil conditions — the 

 alkali content of the soil^ — the texture of the soil and drainage 

 facilities. Thus it is that in the work of classification many factors 

 must be studied, many problems solved before a safe decision can 

 be reached with respect to the wisdom of placing any particular 

 area under irrigation. 



Many of these problems are concerned with the presence of 

 "alkali," the accumulation of certain soluble salts in the soil, charac- 

 teristic of many arid and semi-arid tracts. This alkali may vary 

 in composition and in concentration, as well as in position. It differs 

 also in toxicity to vegetation. 



In the examination of the soils of the semi-dry belt of the Western 

 Prairie provinces, alkali impregnation, though somewhat widely 

 distributed, has not condemned any large irrigation projects as 

 non-irrigable, but there are areas here and there of greater or less 

 magnitude which have been "cut out" on the grounds that irrigation 

 sooner or later would in all possibility result in "rise of alkali" and 

 destroy the land for farming purposes. In the course of the work 

 many doubtful cases occur, rendering it extremely difficult to reach 

 a conclusion; the classification must be safe, if conservative, but 

 the benefits of irrigation are so great that no land should be classed 

 as non-irrigable without unmistakeable evidence that injury would 

 follow the application of water. 



A typical problem of this character is that of a rather extensive 

 tract of land at Tilley. (Sec. 24, Tp. J7, Rge. 13, West 4th Meridian) 

 Alberta. The conditions here are a surface soil of heavy, impervious 

 clay loam of good quality and free from all save traces of saline 

 matter, but very difficult to work and drain. This overlies a subsoil 

 of extremely heavy impervious clay carrying a serious impregnation 

 of alkali. In 1915 it was decided that several years investigations 



