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

Chemical weathering losses were calculated for three conifer stands in relation to ongoing studies on chemical status, soil solution chemistry and soil genesis. Weathering losses were based on elemental depletion trends in soil profiles since deglaciation and exposure to the weathering environment. Gradients in total geochemical composition were assumed to reflect alteration over time. Study sites were Nyänget and Heden in northern Sweden, and Hyytiälä in central Finland. The Nyänget site is located on sandy loamy Weichselian till at an altitude of 310 m a.s.l. and the Heden and Hyytiälä 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 lower but similar values for Nyänget and Hyytiälä. The weathering losses for the elements are in the following order: Mg>Ca>Na>K>Al=Fe>Mn=Si>P. Total annual losses for Ca+Mg+K, expressed in mmolc m−2 yr−1, amounted to 27.2, 16.6 and 19 at Heden, Nyänget and Hyytiälä, respectively. Variations between study sites were consistent with differences in geochemistry and mineralogy. The accumulated weathering losses after deglaciation 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 secondary minerals.