Weathering in three podzolized pedons on glacial deposits in northern Sweden and central Finland

Chemical weathering losses were calculated for three conifer stands in rela tion to ongoing studies on chemical status, soil solution chemistry and soi l genesis. Weathering losses were based on elemental depletion trends in so il profiles since deglaciation and exposure to the weathering environment. Gradients in total geochemical composition were assumed to reflect alterati on over time. Study sites were Nyanget and Heden in northern Sweden, and Hy ytiala in central Finland. The Nyanget site is located on sandy loamy Weich selian till at an altitude of 310 m a.s.l. and the Heden and Hyytiala sites on water-deposited coarse silt and out-wash sand at an altitude of 175 and 150 m, respectively. Volume-determined samples from different soil levels were fused with lithium metaborate, dissolved in HNO3, and analysed by ICP- AES. Results indicated highest cumulative weathering losses at Heden and lo wer but similar values for Nyanget and Hyytiala The weathering losses for t he elements are in the following order: Mg > Ca > Na > K > Al = Fe > Mn = S i > P. Total annual losses for Ca + Mg + K, expressed in mmol(c) m(-2) yr(- 1), amounted to 27.2, 16.6 and 19 at Heden, Nyanget and Hyytiala, respectiv ely. Variations between study sites were consistent with differences in geo chemistry and mineralogy. The accumulated weathering losses after deglaciat ion were much larger in E than in B horizons for all elements studied. For Fe, Al and Si, this was partly due to the retention by precipitation of sec ondary minerals. (C) 2000 Elsevier Science B.V. All rights reserved.