The strongest relationship was for EM38V averaged to 0–150 cm
depth (Table 1). This depth interval includes the zone of highest
ECe (80–140 cm) (Fig. 1) which is likely to correlate with previous
or current high root length density and tree water uptake (Vertessy
et al., 2000). Consequently, the zone between 0 and 150 cm provides
the most useful indicator of salinity in the root zone given the depth
limitation of the EM38. This relationship between EM38V averaged
to 0–150 cm depth (Table 1) was used to convert measurements
of ECa (EM38V) to average ECe (dS cm−1) across the same depth.
When compared with regressions developed by Halvorson et al.
(1977) for sandy loam, clay loam and clay soil texture groups, the
Timmering ECe 0–150 cm derived from EM38V was consistent with
that expected for a clay loam topsoil and light clay subsoil (Fig. 2).