Correction of Alkali Waters 287 



alkali lands except under conditions which are ex- 

 tremely favorable to their formation. 



CORRECTION OF ALKALI WATERS BEFORE USE IN 

 IRRIGATION 



In case an irrigation water is known to contain an 

 injurious amount of black alkali, it is possible to con- 

 vert this into the sodium sulphate by the use of land 

 plaster in the water before applying it to the field. 



To do this in the ^ases where water is stored in 

 reservoirs, it is possible to arrange cribs of uncrushed 

 gypsum through which the water flows in entering the 

 reservoir, and if this should not be sufficient to effect 

 the whole change, other cribs could be built at other 

 points in the reservoir and at the outlet. So, too, 

 where the lateral is taken to the field, it would often 

 not be difficult to arrange so that the water flowed 

 through a basin, wide ditch or reservoir in which hang 

 crates of gypsum, over which the water passes on its 

 way to the field, or the same method may be applied 

 in the larger canals. 



If the fields upon which alkali waters must be used 

 are heavy and especially likely to be injured by the 

 puddling process, it would seem to be much the better 

 method to apply the corrective for black alkali to the 

 water itself, rather than to the field, after there has 

 been opportunity for some damage to be done. 



DRAINAGE THE ULTIMATE REMEDY FOR ALKALI LANDS 



If it is true that alkali salts are formed from the 

 decomposition of the soil and subsoil through the $c- 



