Chemical properties of forest soils along a fly-ash deposition gradient in eastern Germany

Abstract

Chemical characteristics of forest soils subjected to long-term deposition of alkaline and acid air pollutants were analysed in spruce (Picea abies (L.) Karst.) stands in eastern Germany. Three forest sites along an emission gradient of 3, 6, and 15 km downwind of a coal-fired power plant were selected, representing high, intermediate, and low fly-ash input rates. Past emissions caused an accumulation of mineral fly-ash constituents in the organic layer, resulting in an atypically high mass of organic horizons of forest soils, especially in the F and H horizons. Total mass of organic layers at the site with heavy deposition loads was as high as 128 t ha À1 , compared to 58 t ha À1 at the low input site. Fly-ash deposition significantly increased the pH values in the L, F and H horizons and mineral topsoil (0-10 cm). Significantly higher concentrations of NH 4 Cl-extractable cations (i.e. effective cation exchange capacities) and base saturations of >66% were found in the humic horizons at sites where the pH was increased due to the direct and indirect (i.e. higher proportions of deciduous trees) effects of fly-ash emissions. Stocks of basic cations were dominated by Ca 2+ and decreased significantly along the fly-ash deposition gradient from 33.6 to 5.3 kmol c ha À1 . Proportions of water-soluble basic cations out of the total potentially exchangeable (i.e. NH 4 Cl-extractable) basic cations generally increased in the forest soil with decreasing deposition loads following the cation exchange capacity and base saturation along the fly-ash gradient. Higher proportions of monovalent cations, such as K + and Na + , were observed in the water extracts from fly-ash-affected forest soils, while the NH 4 Cl-extracts were dominated by bivalent cations, such as Ca 2+ and Mg 2+ . These results suggest a greater leaching tendency for monovalent cations in these soils. Stocks of organic C and total N in the humus layer decreased from sites with high fly-ash deposition levels to sites with low levels, from 57.4 to 46.4 t C ha À1 and from 2.43 to 1.99 t N ha À1 . The C/N ratios of the organic horizons varied from 22 to 25, revealing no distinct pattern along the fly-ash gradient. Measurements of hot-waterextractable and water-soluble organic C suggested a reduced availability or a faster decomposition of soil organic matter in soils with historically high fly-ash loads.

Testing a Soil Magnetometry Technique in a Highly Polluted Industrial Region in North-Eastern Germany

“…But it still results in elevated magnetic susceptibilities, which are highest close (up to 8 km) to former emitters and decreased with increasing distance from the emitters. These results are in accordance with studies by Klose et al (2001Klose et al ( , 2002, Klose and Makeschin (2005), and Koch et al (2002). The variability of the measured values expressed by standard deviation and coefficient of variation tends also to decrease with increasing distance from the former emitters (Table 3).…”

“…1), where different deposition levels have been found in earlier research (Klose and Makeschin 2005).…”

The influence of the wind direction and plants on the variability of topsoil magnetic susceptibility in industrial and urban areas of southern Poland

“…Consequently, the presence of TMPs in topsoil (mainly in the organic horizon) is considered an indicator for heavy metal soil pollution. This fact was confirmed by many authors (Veneva et al 2004;Klose and Makeschin 2005;Spiteri et al 2005;Blaha et al 2008;Jordanova et al 2008;Lu et al 2008;Magiera et al 2008;Bućko et al 2011). Soil with natural plant cover, particularly forest soil, is often used as a target for magnetic susceptibility studies because it exhibits the stratigraphic sequence of the depositing dusts in undisturbed soil horizons for a long time.…”

Forest ecosystem development after heavy deposition loads – case study Dübener Heide

“…Zooming into the region Leipzig-Halle-Bitterfeld and taking the Dübener Heide -the most important regional forest area -as an example, the historically documented deposition amounted from 1910 -2000 to 18 Mio t fly ash and 12 Mio t SO 2 . In the decade from 1961 -1970, a fly ash deposition of up to 3-8 t / ha * a is reported by Lux [21,24], Neumeister et al [30], Nebe et al [31] and Klose and Makeschin [13]. To demonstrate the extend of deposition impact on the forest soils: pH (KCl) values in the humus layer and upper mineral horizon of the regional forest soils (mainly poor sandy brown soils and podzols) increased in that period from originally 3-4 up to 7-9 and a base saturation of up to 100% is still detectable (Fritz and Makeschin [3]).…”