Abstract

Measurement of transport properties of field soil remains a challenge. Time domain reflectometry (TDR) has been used for rapid and nondestructive measurement of the movement of conservative tracers in controlled laboratory and field experiments. Measuring transport under transient conditions in the laboratory using TDR has also been reported, but obtaining appropriate calibration relationships remains a challenge. We present a method for rapid and nondestructive measurement of field transport of an electrolytic tracer (applied to the soil surface) under transient rainfall and evapotranspiration conditions with net drainage using TDR without any a priori calibrations. The method uses TDR probes in plots with and without a tracer applied. The simultaneous TDR measurements of apparent impedance and dielectric constant in the paired plots were used to calculate the relative solute mass remaining to a given depth (i.e., TDR probe depth) as a function of time during a 270-d field experiment under natural rainfall and evapotranspiration conditions of net drainage. The measurements give relative solute mass flux that is equivalent to the solute travel time probability density function.

You do not currently have access to this article.