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

Tóth, Tibor, Kovács, Zsófia Adrienn, Rékási, Márk
Geoderma 2019 v.342 pp. 106-108
X-ray fluorescence spectroscopy, catenas, clay fraction, dosimetry, grasslands, portable equipment, rubidium, salinity, soil salinity, soil water
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.