Feb. s, 1917 
Measurement of Inactive Moisture in Soil 
203 
RELATION BETWEEN THE AMOUNT OF WATER THAT FAILS TO FREEZE AND 
THE WILTING COEFFICIENT OF SOILS 
The amount of water that fails to freeze under the foregoing empirical 
conditions bears also a remarkable relation to the wilting coefficient of 
soils. In Table III there are presented the total percentage of water 
that fails to freeze and the wilting coefficient of some soils. The per¬ 
centage of water that fails to freeze is expressed on the absolute dry 
basis, in order that it may be directly comparable to the wilting coefficient 
which is similarly expressed. The data on the wilting coefficient were 
obtained experimentally, following the mode of procedure described by 
Briggs and Shantz (4). Wheat was used as an indicator. 
Table III .—Relation between the percentage of water that fails to freeze and the wilting 
coefficient 
Name of soil. 
Percentage 
of water that 
fails to freeze. 
Wilting 
coefficient. 
Sand...... 
1. 40 
3- 52 
10. 50 
17. 30 
IS- 86 
I. 49 
4. 28 
9. 62 
18. 16 
13. 82 
Sandy loam.... 
Silt loam... 
Heavy silt loam.,. 
Do.;. 
A glance at Table III discloses at once the remarkable fact that the 
total percentage of water which does not freeze when the soil is super¬ 
cooled to 3 0 in a temperature of — 4 0 and the ratio of soil to water is 
5 to 1, respectively, is the same as that at which plants begin to wilt, 
or the wilting coefficient. It will be observed that the variation does 
not exceed 2 per cent in any case. 
RELATION BETWEEN THE AMOUNT OF WATER THAT FAILS TO FREEZE 
AND THE PERCENTAGE OF WATER AT WHICH SOLIDIFICATION REFUSES 
TO TAKE PLACE 
As already mentioned, the investigations with the freezing-point 
method showed that solidification could be induced in all soils very 
easily from any maximum moisture content down to a minimum moisture 
content, and then it could not be started. It was shown in a former 
publication (2) that the percentage of water at which solidification could 
not be induced was the same as the wilting coefficient of soils, and it 
was suggested that the freezing-point method may be used to obtain the 
latter value. It may now be of interest to indicate that the percentage 
of water at which solidification refuses to start bears a close relation also 
to.the amount of water which refuses to freeze in the dilatometer. This 
interesting correlation is exhibited in Table IV. 
74549°—17 - 2 
