RELIABILITY OF THE PROPOSED SUCTION METHOD OF DETERMINING THE MOISTURE EQUIVALENT OF SOILS

Publisher Website
Google Scholar
Abstract
In a comparison of the value obtained by Bouyoucos'' proposed suction method with the moisture equivalent detd. with the Briggs-McLane centrifuge, 113 Minnesota soils were used. These ranged in moisture equivalent from 1.5 to 90.6, in N from 0.001 to 2.03%, and in pH from 4.7 to 8.1. Though the relationships found are in general agreement with those reported by Bouyoucos, they do not fully support his conclusions as to the reliability and general desirability of the method. With loams and soils of still finer texture the suction value averaged about 1/10 higher than the moisture equivalent; with the individual soils it varied from practically equal to 1/3 higher. With the sands of coarsest texture it was twice as high, or still higher, and with soils intermediate between these and loams it was generally intermediate but widely variable. Duplicate determinations by the suction method were found much less concordant than those with the centrifuge. Only where a moisture-equivalent centrifuge is not available does the use of the suction method appear desirable, and the values so obtained should be referred to by some other designation than moisture equivalent.