WATER UNDER SALINE CONDITIONS 225 
of accumulation of exchangeable sodium under field conditions 
can be reliably estimated from a chemical analysis of the irrigation 
water. Nevertheless, much of the guesswork has been removed 
from the agricultural use of water under saline conditions. Tests 
are available for appraising the salinity and sodium status of soil 
and for estimating the amount of amendment for reducing ex- 
changeable sodium to an acceptable level. Progress is being made 
toward putting this information to practical use by farmers.* 
* Agricultural research dealing with salinity, exchangeable sodium, 
drainage, leaching, salt tolerance of crops, and quality of irrigation 
water has been conducted by numerous agencies in this country and 
abroad. Information on these subjects has been summarized in the U.S. 
Department of Agriculture Handbook No. 60 entitled “Diagnosis and 
improvement of saline and alkali soils.’ Also see Circular, “Tests for 
salinity and sodium status of soil and irrigation water.” These are ob- 
tainable from the Superintendent of Documents, U. S. Government 
Printing Office. 
