XRF-measured rubidium concentration is the best predictor variable for estimating the soil clay content and salinity of semi-humid soils in two catenas

Tibor Tóth, Zsófia Adrienn Kovács, Márk Rékási

Geoderma 342 (2019) 106–108


When making management decisions regarding the conditions of the Great Hungarian Plain, it is important to
consider the soil clay content and soil salinity. Because the soil moisture conditions vary from extremely dry to
extremely wet throughout the year, this limits the use of electric methods. In this study, we looked for fast,
independent techniques to estimate soil clay content and soil salinity. Gamma dosimetry and X-ray fluorescence
spectroscopy (XRF) were tested and showed consistent values. In two contrasting transects: one passing from top
of the dune to the valley (Sanddune-Valley), and another passing from an elevated non-sodic grassland to low
sodic patches (Sodic), the XRF-measured rubidium concentration proved to be the best overall predictor of both
soil clay content and salinity as it provided better correlations than gamma dosimetry. Pearson correlation
coefficients indicated opposing tendencies between the rubidium concentration and the soil clay content and
salinity in the transects, owing to distinct differences in the soil formations inside the transects. We suggest using
XRF and not gamma dosimetry for the field estimation of soil clay content and salinity with portable devices.