Sick Soils not Influenced by Parasites 39 



pounds may be carbonate of soda, and 6880 pounds 

 common salt. BroccoK, chard, fennel, and sweet com 

 will thrive fairly wdl in lands containing up to a total 

 of 3720 pounds of alkali per acre. 



Haw to Reclaim Alkali Soils. We have seen that 

 the accumulation of alkali in a soil is often brought 

 about by the evaporation of water which is charged 

 with mineral salts. To obviate this it is evident 

 that the evaporation must be coimteracted. Good 

 surface cultivation wiU establish a dry surface 

 mulch and prevent the rise of water to the upper 

 level, thereby preventing evaporation. Tillage to 

 be eflEective must be started early, because then, 

 large quantities of salt would be carried into the 

 subsoil by the spring rains. If the crop is started 

 early, it may be forced to maturity before the effect 

 of alVali can make itself felt on the plants. Tillage, 

 however, will afford only temporary relief, as it will 

 not remove the salts from the soU. Drainage on the 

 other hand affords permanent relief. The land is 

 first flooded, preferably in the winter, and then the 

 water which is now laden with soluble salts is removed 

 by a system of drainage. Tile drainage, while more 

 exi)ensive in its initial cost, is cheapest in the long 

 run. Such a sjrstem when laid down permanently 

 will prevent the further accumulation of salts. 



The application of manure or straw to alkali land 

 often brings marked relief. Many a barren spot has 

 been redaimed by this method. The beneficial 

 action of manure or straw is easily accounted for. 

 Both of these tend to loosen the surface soil, thereby 



