48 
Journal of Agricultural Research 
Vol. V, No. i 
The top line in each case gives the results where no salts were applied. 
Below this the figures are arranged according to the total quantity of 
salt used, first 1,000 p. p. m., followed by 2,000, 4,000, 6,000, 8,000, and 
10,000. It will be noted that with the chlorids and nitrates practically 
no plants grew in the higher concentrations. Careful study of the table 
is necessary to see the numerous complex relations that are brought out 
between the various salts. The simple relations may be seen more 
easily in figures 2 to 24, but by bringing together a large mass of data 
in one table many relations can be found that could not be seen in the 
diagrams. 
The average alkali of Utah contains a mixture of chlorids, sulphates, 
and carbonates, with the carbonates usually present only in small quan¬ 
tities. The practical alkali problem, therefore, is largely centered around 
the sulphates and chlorids of sodium. An examination of Table XVI 
does not seem to indicate that either of these salts has any great neu¬ 
tralizing effect on the other. 
A general conclusion from this table might be that where alkali salts 
are found together in the soil the toxic action of the combined salts is 
only slightly less than the sum of the toxidties of the individual salts. 
It may be that with other combinations of salts this conclusion would 
not be justified. 
PRACTICAL LIMITS OF THIS PROBLEM 
The practical problem of this entire study is to determine the quan¬ 
tity of various alkali salts necessary in the soil to reduce the growth of 
crops beyond the point of profitable production. Under the conditions 
of dry farming there is no practicable way of removing excessive soluble 
salts; hence, if salts are found in these soils in quantities prohibiting 
crop growth, the soils are valueless for agriculture. On the other hand, 
soils that are susceptible of irrigation and drainage may be reclaimed 
by the leaching out of the alkali. In any soil, however, where there is 
a likelihood of alkali injury it is very important, in order to be able to 
judge the value of a soil, to know exactly how much of a given salt 
is necessary to injure crops. The literature on the subject up to the 
present is somewhat conflicting and lacks the definiteness that would 
be desirable. 
There are so many factors entering into the toxicity of alkali that it 
is difficult to assign definite toxic limits. For example, an analysis 
might show a soil to contain a given percentage of salt when in reality 
the greater part of the salt might be in a crystallized form at the sur¬ 
face, where it would do no harm until dissolved and washed back into 
the soil. It is the salt in solution that does the real injury. The wetness 
of the soil, its texture, the presence of neutralizing substances, and a 
number of other factors all alter the toxicity of soluble salts, which 
