ABSTRACT
Since 1980, other researchers have noted that the quantity [tt/(2L)] in Eq. (3) is quadratic, and have shown that the relationship between yv and tt/(2L) is practically linear (e.g., Ref.[15]). Several attempts have been made to predict ea of soils from theoretical considerations using dielectric mixing models that consider the volumetric proportions of soil mineral, organic, water, and air constituents, as well as soil mineralogy and particle shape and packing considerations (e.g., Refs.[16-18]). Success could lead to a more universal calibration, but has been elusive;[19] so that Eq. (4) and like empirical calibrations for specific soils (particularly electrically conductive soils including clays with high charge, and organic soils) are still considered to be the accepted standards.
