Magnetic susceptibility of Entisols and Aridisols great groups in southeastern Iran

Abstract

This study was performed to explore the variability of magnetic susceptibility between soil great groups in an arid region including seven soil great groups of south-eastern Iran. In the studied area 126 soil profiles were described and classified in seven soil great groups according Soil Survey Staff. Soil samples were collected from control sections and some soil properties such as organic matter (OM), calcium carbonate equivalent (CCE), gypsum, pH, electrical conductivity (EC), dithionite extractable iron (Fed), oxalate extractable iron (Feo), magnetic susceptibility at low and high frequencies (χlf and χhf) and frequency-dependent magnetic susceptibility (χfd) were measured in the laboratory. The lowest χlf was obtained for Torriorthents and Torripsamments soil groups with lowest soil development degree. The highest magnetic susceptibility was observed for Calcigypsids and Haplocalcids soil great groups. Similar trend to χlf was observed for seven studied soil great groups in respect to Fed and inversely trend to χfd. Correlation analyses revealed that Fed was significantly related with χlf and low value of χfd in all soil profiles revealed the formation of stable single domains (SSD) due to pedogenic processes. Achieved negative correlations between χlf and carbonates, organic matter and gypsum confirmed diamagnetic behaviors of these soil components. The results of discriminant analysis indicated that combining magnetic measures such as magnetic susceptibility and dependent susceptibility and iron forms could not successfully predict all soil great groups in the studied area and average 57% accuracy was achieved.