Magnetic Susceptibility Related to Soil Properties in Different Land Uses of Bardsir Region, Kerman Province

Soil magnetic properties reflect the complex chemical, geological and biological interactions occur in the soil. Thus, knowledge about the factors affecting soil magnetic properties helps better understanding and interpreting the results.. The lithogenic magnetic minerals are often found in the coarse soil fractions (sand and silt) and they have inherited from parent rocks. Weathering and soil formation factors may lead increasing or decreasing of magnetic susceptibility. Climate and vegetation type are among the other factors affecting magnetic susceptibility too. Amount and distribution of magnetic susceptibility may also be affected by land use. The main objective of this research was to study the effect of different land uses and vegetation types on the magnetic susceptibility of topsoil related to soil properties.
The study area was located in MahoonakeZiba around the Bardsir region, Kerman Province. The moisture and temperature regimes of the study area were sub aridic and mesic, respectively. The study area is located in the alluvial plain with igneous parent material originated from andesite, volcanic tuff, anddacite. Four land uses including farmland, well-covered pasture, disturbed pasture and degraded dryland farm with similar climate, topography, and parent material were selected. Overall, 60 complex surface samples were collected from the depth of 0-15 cm. The physicochemical analyses were done on the samples after that the soils were air dried, crushed, and passed through a 2 mm sieve. The soils magnetic susceptibility (ᵡ) in low (0.46 kHz) and high (4.6 kHz) frequencies were measured using the Bartington MS2 dual frequency sensor in two replications. The frequency depended magnetic susceptibility (ᵡfd %) was calculated as a development index of soil forming factors reflecting ferrimagnetic particle sizes.
The pH of studied soils were in the range of neutral to alkaline and had the lowest coefficient of variance between measured parameters. The average of soil EC was 1.76 dS/m with a high coefficient of variance. The lowest amount of organic matter was in land use ofdegraded drylandfarm (0.26 %) and the highest was in farmland (2.15 %). The lowest amount of calcium carbonate with the coefficient of variance 12.37 % measured in the degraded pasture and its maximum was in the farmland. The loamy sand and sandy loam textural classes were found in the area under study. The minimum and maximum amounts ofᵡlf were determined in farmland (134.8× 10-8 m3 kg-1)and well-coveredpasture (1778.9 ×10-8 m3 kg-1 ), respectively and the relatively high mean value was 695.83 × 10-8 m3 kg-1. The topsoil of the study area was formed on alluvial deposits with a parent material originated from igneous andesite, tuff and dacite rocks. The high values of magnetic susceptibility of all soils under study could be attributed to the existence of initial magnetic minerals inherited from the parent material. The statistical analysis revealed a significant difference among ᵡlf values (p