SOILS IN DRY AREAS 75 



They lead to a plasticity of condition when it is wet, 

 and they cause it to become cloddy when dry. 



Fortunately alkali soils do not usually cover large 

 areas. More frequently they occur in spots and espe- 

 cially where water collects in low ground at certain sea- 

 sons of the year. In some instances, however, consid- 

 erable bodies of land occur that are more or less impreg- 

 nated with alkali. Such soils are very undesirable for 

 tillage. 



Because of the difficulty found in tilling these soils 

 their value is very low for agricultural uses at the present 

 time, whatever the future may reveal. Because of this 

 such lands should not be chosen for agricultural uses 

 until more is known as to how they may be handled. 

 They are usually exceedingly rich. The great obstacles 

 to their tillage are, first, the difficulty found in handling 

 them, and, second, the burning of the seed or crop that 

 may be sown on them. 



The removal of alkali when present in excess is 

 seldom an easy proposition and in some instances it is 

 not practicable. The first step in removing it is to sup- 

 ply thorough and complete drainage either through the 

 agency of open or of tile drains. In some instances 

 black alkali in solution will not enter the latter. In such 

 instances it should be changed to white. This is done 

 by adding considerable quantities of gypsum ; that is, of 

 sulphate of lime, which Becomes carbonate of lime. When 

 thus changed, the alkali may be washed down and out 

 in the drainage water which is thus carried off in the 

 drains. The second step is to work into the soil from 

 10 to 20 tons per acre of strawy horse manure in the 

 summer or early fall, in areas where much of the pre- 

 cipitation comes in the winter, or in the spring when it 

 comes subsequently to that time. It tends to prevent 

 evaporation from coming to the surface, makes the soil 

 more open and porous, and correspondingly reduces the 



