Agricultural Use of Water Under 
Saline Conditions 
L. A. RICHARDS 
United States Salinity Laboratory, Riverside, 
California 
The question of whether irrigation agriculture can persist per- 
manently has been included among other subjects for considera- 
tion at these meetings. The principal difference between irrigated 
and nonirrigated agriculture, when considered in relation to per- 
sistence or permanence, arises from salinity. All waters used for 
irrigation contain more or less soluble material. It is only a matter 
of time until these solutes will accumulate in the root zone to the 
extent that plants will not grow, unless some leaching occurs. This 
generalization appears final and pessimistic, but, of course, it 
would be difficult indeed to practice irrigation without some net 
transfer of water downward through the root zone. Adequate 
leaching often occurs on irrigated farms without thought or atten- 
tion by the farmer. If this is not the case, salt will accumulate, 
and eventually soil and water management operations will have to 
be altered accordingly. 
Water Conductance of Soils 
Leaching is accomplished by the downward movement of water 
through soil. To be adequately drained, any water table that tends 
to form in irrigated land must be kept well below the root zone. 
This requires that outlets be available for the ground water and 
that water transmission in the subsoil be appreciable. Because of 
its relation to water application methods and to leaching, the rate 
at which a soil will transmit water is one of its most important 
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