UTAH ACADEMY OF SCIENCES 89 
majority of Utah irrigation waters, is said to be fit for 
irrigation until it reaches a strength of about 1,250 to 
1,500 parts per million of alkali salts or where the total 
salts are about double this quantity. 
Where water known to contain alkali in such large 
quantities as to be harmful is flowing past farms threat- 
ened with drouth, it is a great temptation to use the 
water for a single irrigation with the intention of wash- 
ing the salts from the soil when purer water can be had. 
In the Bear River Valley on a clay loam soil, a farmer 
used the water from the Malad River which contains 
over 4,000 parts per million of salts, mostly sodium chlor- 
ide, to irrigate a grain field. The grain almost immedi- 
ately wilted and the crop was lost. Such water might 
have been endured for the season on a lighter and better 
drained soil. 
Most of the irrigation waters of Utah contain such 
small quantities of alkali salts that they may be classi- 
fied as good under ordinary conditions. Perhaps a dozen 
of the streams and rivers fall in the class which are of 
dubious quality, and a few of these are unquestionably 
harmful under the local conditions. Springs and wells 
vary so much in alkali content in different places that 
individual analyses must be made before their quality 
for irrigation can be determined. (For analyses of some 
of the more important streams of the state, and a number 
of wells and reservoirs used for irrigation, Bulletins 147 
and 163 of the Utah Experiment Station are instructive.) 
Under field conditions, the injury done by alkali 
in irrigation water is difficult to determine definitely 
because of alkali already in the soil, accumulation of the 
salts in the upper strata of the soil, and the interfering 
action of various non-alkali salts. To study the factors 
separately, a number of experiments were begun at the 
Utah Experiment Station in 1915 and continued until 
1918. 
The first experiment consisted of two series of 
earthen jars, one containing loam soil and another sand, 
to which the alkali salts were added in pure solutions 
somewhat as under ordinary irrigation. To avoid evap- 
oration from the jars with its consequent accumulation 
of the salts at the surface, the tops of the jars were cov- 
