THE TREATMENT OF ALKALI. 33 



strata of soil, and thus diluting it and partially neutraliz- 

 ing its injurious presence. As shown in the preceding 

 chapter, cultivation also checks evaporation, and hence 

 currently lessens the deposits of alkali on the surface. 

 A loose, dry topsoil acts as a cushion of earth and air, 

 intercepting the continuity of the upward passage of 

 moisture along the lower plane of cultivation. 



The Flooding System. The most effective means 

 of getting rid of ordinary white alkali is by washing it 

 out of the land. This can bo accomplished by digging 

 open ditches at a lower level than the surface of the land 

 to be treated, and carrying them to the nearest natural 

 outlet. Then by running water over the land into the 

 drains without allowing it to stand long enough to soak 

 into the ground and carry the dissolved alkali with it, 

 most of the alkali that has accumulated at the surface 

 will be removed. By repeating this treatment a few 

 times land can be practically freed from alkali, unless it 

 is exceptionally bad. Another plan is to use the blind 

 ditcher, a machine much like the old ox plows used in 

 Illinois and Iowa thirty years ago to make blind ditches 

 along the prairie sloughs. This implement is calculated 

 to run ditches from four to six inches lower than the 

 plowed ground, every sixty or eighty feet across the tilled 

 ground, to serve as drains. Another plan, and to our 

 notion the most practicable one suggested, as well as the 

 most expensive, is to underlay alkali land with vitrified 

 sewer pipe. This will last a lifetime and will certainly 

 get away with the alkali. 



Chemical Antidotes. When the quantity of 

 alkali is small the evil effects resulting from its presence 

 may be mitigated by the application to the soil of chemi- 

 cal antidotes. A cheap antidote for most alkaline salts 

 is lime. In some cases neutral calcareous marl will 

 answer the purpose. When the alkali consists of car- 

 bonates and borates, the best antidote is gypsum or land 

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