Magnetic susceptibility of soils in different slope positions in Saskatchewan, Canada

The magnetic susceptibility (chi) of soils varies with the slope position d ue to some factors, such as texture and drainage class. This study attempts to link chi to soil profile characteristics [soil horizon type, organic an d inorganic C, sand and oxalate (Feo) and dithionite (Fed) extractable iron ] measured on soil cores collected from the three uncultivated soil catenas in Saskatchewan. The parent material at all sites consisted of medium-text ured hummocky glacial till. The Waitville catena (Gray Luvisol) was develop ed under trees, the Weyburn catena (Dark Brown Chernozem) under grass, and the Oxbow catena (Black Chernozem) had trees on the lower slope and grass i n the center of the depression and on the upper and middle slopes. In all t he three catenas, a downslope decrease in chi was correlated with increasin g Feo/Fed ratios and decreasing sand content. Lower slope gleyed profiles i n the two Chernozemic catenas had high Feo/Fed ratios and low chi The impac t of gleying was most evident in the solum and chi tended to increase in th e C-horizons of these profiles. The chi of the sand and silt fractions was positively correlated with that of the bulk soil, whereas, the chi of the c lay fraction did not vary with the chi of the bulk soil. Stable sand-sized magnetite: grains are believed to be rare in these soils. (C) 2000 Elsevier Science B.V. All rights reserved.