152 PRINCIPLES OF RURAL ECONOMICS 



subsoil. Thus it is sometimes possible to remove from one third 

 to one half the total alkali from the soil in a single year. 



4. Very deep plowing. This has the effect of removing the 

 crust of strongly impregnated surface soil to a greater depth, 

 where it is mixed with the mass of the soil and is thus less in- 

 jurious to plant growth. 



5. Neutralizing the more injurious salts, that is, ''black al- 

 kali." A liberal application of land plaster or gypsum is found, 

 in certain cases, to be sufficient. 



6. Counteracting evaporation. This is everywhere neces- 

 sary, no matter what other methods are adopted. The " dust 

 mulch " as applied to dry farming, artificial mulching, shading, 

 or any method which will reduce the rate of evaporation will in 

 light cases be found sufficient, and will in all cases be found 

 helpful. 



7. Introducing crops which will endure alkali. Alfalfa and 

 Australian salt bushes are found adaptable in some cases, and 

 experiments are still being carried on to find other crops which 

 will grow in alkali soil. 



Salt marshes. The salt marshes along the seacoasts and at the 

 mouths of rivers form another type of land which is now going 

 to waste, partly because of bad chemical conditions, but mainly, 

 perhaps, because of bad physical conditions. The reclamation 

 of such lands, however, is simply a matter of diking and drain- 

 ing, diking to keep out the salt water, and draining to carry 

 off the fresh water. The fresh water, if it can be carried off, 

 will soon carry the salt with it and leave the soil in condition to 

 grow crops. This is, therefore, merely a part of the drainage 

 problem and should be treated as such. 



Bad political conditions. No observer can have failed to notice 

 considerable tracts of valuable land, especially in the neighbor- 

 hood of our large cities, which are lying idle. This land is 

 going to waste in the sense that it is producing nothing for the 



