Depth profiles of potassium and its isotope ratio (40K/K) in several forest soils

Abstract

Depth profiles potassium and its isotope ratio ( 40 K/K) were investigated in several forest soils from different geological and climatic backgrounds. The ratio was found not to be constant (0.0117 %) but varied appreciably from 0.0085 to 0.0167 % among different soils.Possible factors affecting variability of 40 K/K values were considered by a multivariate factor analysis which suggested that aqueous parameters like humidity and pH might be a controlling factor in the surface soils. The amount (and probably chemical forms) of iron oxide may be another one influencing 40 K/K values in mineral components at deeper portions.

Tracing depositional consequences of environmental radionuclides (137Cs and 210Pb) in Slovenian forest soils

“…137 Cs burial rate (cmy −1 ) ranged from 0.06 (P5) to 0.25 (P3) with the highest value at P3 under undisturbed beech stand in Kočevski Rog. Our previous investigation gave a relatively constant mean burial rate of 137 Cs of about 0.1 cm y −1 in different forest soils collected from various locations [2][3][4]. The findings in this study may also support our previous results.…”

“…The present authors obtained similar values of 137 Cs (and also 210 Pb) burial rate to those reported by Clouvas et al [9] in undisturbed forest soils from different places in Hokkaido, Japan, Germany, the Czech Republic and Peru [2][3][4]. Dynamic processes in soil were investigated using these nuclides of different origin and different chemical properties as radiotracers.…”

Variability of 40K isotopic composition in forest soils under different environmental conditions

“…2b) -2 to 0.78 9 10 -2 %) appeared in the 216 surface portion (down to a depth of about 5 cm) compared 217 with those (0.86 9 10 -2 to 1.07 9 10 -2 %) in deeper part 218 (lower than 30 cm in depth) of the soil independent of the 219 location. Similar 40 K/K depth distribution profiles were 220 obtained in other locations of different geology [17].…”

“…The 321 result indicates that 40 K is enriched in the soils abundant in 322 SOM. Our previous investigation in Sapporo gave a similar 323 result [17]. As a possible evidence of changing 40 K/K ratios, 324 a plant species (Equisetum hyemale L.) and a litter sample 325 gave quite different 40 K/K values to those in the soil 326 (0.9 9 10 -2 to 1.3 9 10 -2 %) collected in November 2010 327 from semi-natural woods on the campus of Hokkaido Uni-328 versity in Sapporo, Japan.…”

“…These findings suggest that the presence of SOM in 256 early diagenetic stage (or possible biological activity) may 257 affect 40 K/K values to a great extent. The presence of soil 258 organic matter and biological activity were suggested to 259 play an important role on 40 K/K distribution profiles in 260 Peruvian surface soil [17]. Further investigation is neces-261 sary to elucidate biological effects on soil 40 K/K dynamics 262 by monitoring various soil components in the forest floor 263 for a long time.…”