68 SOILS 



The injurious salt may be changed into another 

 material that is less harmful by dressing the soil 

 with gypsum, or land plaster. An application of 

 four to six hundred pounds per acre is considered 

 sufficient. This treatment is valuable only for 

 black alkali. When a quarter or more of the salt 

 is on or near the surface, as is often the case, it is 

 sometimes practicable to scrape the surface and 

 cast the scrapings elsewhere. 



Certain plants, notably greasewood and the 

 Australian Salt-bush, thrive on alkali soils and 

 take large quantities of salts from them. Occa- 

 sionally it is practicable to crop soils that are very 

 alkaline with these plants for several years, to 

 remove part of the salts. The plants should not 

 be burned on the land, however; ashes of all kinds 

 and especially these, make the soil more alkaline. 

 A crop of Australian salt bushes produces 15 to 

 20 tons of excellent green forage per acre, or 3 to 5 

 tons of dry forage. This plant grows well upon 

 black alkali. 



Some soils that are very badly alkaline may not 

 be worth the attempt to reclaim; those that are 

 only mildly alkaline it will certainly pay to reclaim, 

 providing they possess the other requisites of a 

 fertile soil. Usually it takes several years to com- 

 pletely remove the objectionable salts, but if the 

 soil is under-drained a fair crop can be grown upon 

 it the second season. Deep plowing should be 

 given to all soils that are more or less alkaline. 

 Thorough tillage lessens the evaporation of water 

 and hence lessens the amount of salt deposited upon 

 the surface. Hilgard says, "When the alkali is not 

 very abundant nor very noxious, frequent and 

 deep tillage may afford all the relief needed. More 

 than half the alkaline land in this state (California) 



