242 JUDGING ALKALI LAND 



General Appearance. -One who is familiar with alkali 

 can tell a great deal by the general appearances of the land. 

 The presence of surface accumulations of salts, the nature 

 of the crust, the general condition and kind of vegetation, 

 the appearance of the subsoil in cuts and excavations, the 

 slope of the surface, the soil texture and structure, and 

 numerous other general appearances are helpful in judging 

 alkali conditions. These superficial observations, however, 

 must not be relied on completely. For example, a soil 

 having a high gypsum content and being free from the 

 highly soluble salts may, through constant evaporation 

 of water at the surface, cause the soil to be covered com- 

 pletely with white powdery crystals which would seem to 

 indicate a serious alkali condition. Land of this character 

 could easily be undervalued since the gypsum is not suf- 

 ficiently soluble to cause injury to vegetation and its 

 presence might not be undesirable. 



On the other hand, a soil may show very little surface 

 indication of alkali; it may contain a good growth of certain 

 kinds of vegetation; yet an analysis might show that at 

 some distance below the surface there is a layer of soil 

 that is highly charged with salts. This land would only 

 need to be brought under cultivation and irrigated to make 

 the subsoil alkali a real source of danger. Appearances 

 are helpful, but alone they are not sufficient. 



Native Vegetation. - - As already discussed in con- 

 siderable detail in Chapter VI, the native vegetation is 

 one of the most valuable indicators of the presence of 

 dangerous quantities of alkali. It is probably the best 

 single means of judging alkali land. Certain plants 

 such as sagebrush (Artemcsia- tridentata) do not live in 

 the presence of high concentrations of salts and where 

 these plants are found growing vigorously the land may 



