Using magnetic susceptibility to discriminate between soil moisture regimes in selected loess and loess-like soils in northern Iran

摘要

This study used discriminant analysis to determine the efficacy of magnetic measures for discriminating between four soil moisture regimes in northern Iran. The study area was located on loess deposits and loess-like soils containing similar parent material. Four soil moisture regimes including aridic, xeric, udic, and aquic were selected. A total of 25 soil profiles were drug from each regime and composite soil samples were collected within the moisture control section. A set of magnetic measures including magnetic susceptibility at low (chi(lf)) and high (chi(hf)) frequencies, frequency-dependent magnetic susceptibility (chi(fd)), saturation isothermal remnant magnetization (SIRM), and isothermal remnant magnetization (IRM100 mT. IRM (20 mT)) were measured in the laboratory. Dithionite citrate bicarbonate (Fe-d) and acid oxalate (Fe-o) contents of all soil samples were also determined. The lowest and highest chi(lf) and chi(hf) were observed in aquic and udic moisture regimes, respectively. A similar trend was obtained for Fe-d and Fe-d-Fe-o. The significant positive correlation between Fe-d and SIRM (r = 0.60; P < 0.01) suggested the formation of stable single domains (SSD) due to pedogenic processes. The results of discriminant analysis indicated that a combination of magnetic measures could successfully discriminate between the selected moisture regimes in the study area (average accuracy = 80%). It can thus be concluded that magnetic measures could be applied as a powerful indicator for differentiation of soil moisture regimes in the study area. (C) 2016 Elsevier B.V. All rights reserved.