The Experts below are selected from a list of 2526 Experts worldwide ranked by ideXlab platform

Hermann F. Jungkunst - One of the best experts on this subject based on the ideXlab platform.

  • Methane Budget of a Black Forest Spruce Ecosystem Considering Soil Pattern
    Biogeochemistry, 2005
    Co-Authors: S. Fiedler, B. S. Höll, Hermann F. Jungkunst
    Abstract:

    Study included seven soils, an adjacent spring and brook and was conducted to estimate CH_4 source and sink strengths of forest soils along a wetness gradient, i.e. their exchange with atmosphere ( direct emission), and hydrosphere ( indirect emission). Soils are represented by anaerobic Histosol, oxic Cambisols, Histosol with degraded peatlayers and Gleysols having intermediate redox state. They could be separated into three emission groups: CH_4 emitting (248–318 kg C ha^−1 a^−1), CH_4 uptake (−0.1 to −5 kg C ha^−1 a^−1), and soils on the edge of CH_4 uptake and release (−0.2–20 kg C ha^−1 a^−1). Although soils with CH_4 uptake were dominant (75%), the soil specific CH_4 budget identified the study field (6.53 ha) as CH_4 source (40.9 kg C ha^−1 a^−1). Not only CH_4 emissions, but also dissolved CH_4 in soil solution varied regularly with soil type. Individual soil solutions contained 0.008–151  μ mol CH_4 l^−1. CH_4 vanished to negligible loads, when dissolved CH_4 passed an oxidative downslope soil zone, but promoted CH_4 uptake was measured at this soil. In turn, CH_4 was discharged to the atmosphere, when the soil solution left the pedosphere across an anaerobic soil zone. These measured indirect emissions were low (34 g C a^−1), but the values of individual soil solution indicate possible higher discharges (3.9 kg a^−1) at a different soil pattern. The results suggest that CH_4 uptake rates of temperate forests are overestimated.

  • N2O emissions of a mature Norway spruce (Picea abies) stand in the Black Forest (southwest Germany) as differentiated by the soil pattern
    Journal of Geophysical Research, 2004
    Co-Authors: Hermann F. Jungkunst, Sabine Fiedler, Karl Stahr
    Abstract:

    [1] Nitrous oxide is a greenhouse gas contributing to stratospheric ozone depletion with major sources that derive from soils. Most measurements were performed at well-aerated or anaerobic sites, excluding common hydromorphic soils (e.g., Gleysols). The main thesis of this study was that the intermediate aeration of such soils promotes N2O emissions. The investigated catena “Wildmooswald,” which is little more than 200 m long, includes common temperate forest soils (n = 7) of three aeration categories (Cambisols, Gleysols, and Histosol). The influence of fluctuating water tables of the Gleysols led to distinctively higher N2O release compared to the Cambisol within the same mature Norway spruce ecosystem. Even a stable “hot spot” of N2O emissions was detected at a Histosol, where artificial drainage created a redox environment comparable to the Gleysols. Ranking the soils according to emission rate results in fairly regular doubling steps; for example, mean annual flux rates in kg N ha−1 yr−1 for the 2.5 years of measurements were −0.1, 0.4, 1.0, 1.9/1.9, 3.2, and 6.4 for Fibric Histosol, Chromic Cambisol, Endoskeletic Cambisol, Histic Gleysol 1/2, Humic Gleysol, and Sapric Histosol, respectively. The annual emission rates (0.93 kg N ha−1 yr−1) of the predominant Cambisols (63.4% of the area) are comparable to other studies, but only 34.3% of intermediately aerated soils led to a redoubling of the average to 1.86 kg N ha−1 yr−1, which is clearly higher than previously presented from temperate forests. Therefore N2O releases of soils are underestimated if soils having intermediate aeration conditions are left unconsidered.

  • N2O emissions of a mature Norway spruce (Picea abies) stand in the Black Forest (southwest Germany) as differentiated by the soil pattern
    Journal of Geophysical Research, 2004
    Co-Authors: Hermann F. Jungkunst
    Abstract:

    Nitrous oxide is a greenhouse gas contributing to stratospheric ozone depletion with major sources that derive from soils. Most measurements were performed at well-aerated or anaerobic sites, excluding common hydromorphic soils (e.g., Gleysols). The main thesis of this study was that the intermediate aeration of such soils promotes N2O emissions. The investigated catena "Wildmooswald,'' which is little more than 200 m long, includes common temperate forest soils (n=7) of three aeration categories (Cambisols, Gleysols, and Histosol). The influence of fluctuating water tables of the Gleysols led to distinctively higher N2O release compared to the Cambisol within the same mature Norway spruce ecosystem. Even a stable "hot spot'' of N2O emissions was detected at a Histosol, where artificial drainage created a redox environment comparable to the Gleysols. Ranking the soils according to emission rate results in fairly regular doubling steps; for example, mean annual flux rates in kg N ha(-1) yr(-1) for the 2.5 years of measurements were -0.1, 0.4, 1.0, 1.9/1.9, 3.2, and 6.4 for Fibric Histosol, Chromic Cambisol, Endoskeletic Cambisol, Histic Gleysol 1/2, Humic Gleysol, and Sapric Histosol, respectively. The annual emission rates (0.93 kg N ha(-1) yr(-1)) of the predominant Cambisols (63.4% of the area) are comparable to other studies, but only 34.3% of intermediately aerated soils led to a redoubling of the average to 1.86 kg N ha(-1) yr(-1), which is clearly higher than previously presented from temperate forests. Therefore N2O releases of soils are underestimated if soils having intermediate aeration conditions are left unconsidered. [References: 42

Ermanno Zanini - One of the best experts on this subject based on the ideXlab platform.

  • Spodosol-Histosol evolution in the Krkonoše National Park (CZ)
    Geoderma, 2006
    Co-Authors: Eleonora Bonifacio, Stefania Santoni, Luisella Celi, Ermanno Zanini
    Abstract:

    Abstract Podzols often occur in association with organic soils along sequences governed by relief, with peats in depressions and podzols on slopes. The formation of bogs has also been described as a soil-induced process: the formation of cemented pans, impermeable to water, in highly developed podzols, enhanced the accumulation of organic matter and slowed down its decomposition. Humans may interfere with soil development, enhancing acidification and thus the eluvial phase of podzolisation, as it may be in the case of acid precipitation or of the plantation of conifers. The aim of this work was to study the transition between Spodosols and Histosols, in the Krkonose National Park (CZ), where spruce has substituted the natural vegetation and acid precipitation has damaged several areas of the park. The soils were studied at two sites: one site is relatively preserved and soils (Spodosols and Inceptisols) develop on a steep slope. At the other site, a gently undulating mountain summit, Spodosols are associated to Histosols and the forest decline is more severe. Three Spodosols (Humic Haplocryod, Typic Cryaquod, Placic Cryaquod) and a Histosol were selected at the second site, and the soil properties and organic matter dynamics were compared to those of a Typic Haplocryod sampled at the first site. Profile morphology and chemical analyses indicated that podzolisation has been more intense at the second site, probably because of the differences in relief and in the amount of water available for pedogenic processes: a high accumulation of organic matter and thick Bhs horizons were the most striking differences, together with depletion in Fe from eluvial horizons. Moreover a trend in the chemical indicators of podzolisation was appreciated among the profiles sampled at the second site. The analyses of organic matter and humic substances indicated that, in Bs horizons, the organic matter characteristics were very similar in the two sites, but in the eluvial and organic horizons marked differences appeared. At the first site, the fulvic acids in the E horizons were small and oxidised, similar therefore to those found in the Bhs horizons, whereas at the second site fulvic acids became bigger, more aliphatic and less oxidised and were therefore less prone to migration. Some of these properties of organic matter were linked to soil water regime, others to the shift in vegetation from forest to grass cover and seemed therefore to be related to the soil evolution itself, being podzolisation in this sense a self-limiting process. Acid precipitation may however have played a role in the change of size of fulvic acids, which were very rich in sulphur, through C–S linkages. The complex interaction between natural and anthropogenic factors seemed to have decreased the ability of organic matter to migrate, enhancing the formation of Histosols.

  • Spodosol-Histosol evolution in the Krkonoše National Park (CZ)
    Geoderma, 2006
    Co-Authors: Eleonora Bonifacio, Stefania Santoni, Luisella Celi, Ermanno Zanini
    Abstract:

    Abstract Podzols often occur in association with organic soils along sequences governed by relief, with peats in depressions and podzols on slopes. The formation of bogs has also been described as a soil-induced process: the formation of cemented pans, impermeable to water, in highly developed podzols, enhanced the accumulation of organic matter and slowed down its decomposition. Humans may interfere with soil development, enhancing acidification and thus the eluvial phase of podzolisation, as it may be in the case of acid precipitation or of the plantation of conifers. The aim of this work was to study the transition between Spodosols and Histosols, in the Krkonose National Park (CZ), where spruce has substituted the natural vegetation and acid precipitation has damaged several areas of the park. The soils were studied at two sites: one site is relatively preserved and soils (Spodosols and Inceptisols) develop on a steep slope. At the other site, a gently undulating mountain summit, Spodosols are associated to Histosols and the forest decline is more severe. Three Spodosols (Humic Haplocryod, Typic Cryaquod, Placic Cryaquod) and a Histosol were selected at the second site, and the soil properties and organic matter dynamics were compared to those of a Typic Haplocryod sampled at the first site. Profile morphology and chemical analyses indicated that podzolisation has been more intense at the second site, probably because of the differences in relief and in the amount of water available for pedogenic processes: a high accumulation of organic matter and thick Bhs horizons were the most striking differences, together with depletion in Fe from eluvial horizons. Moreover a trend in the chemical indicators of podzolisation was appreciated among the profiles sampled at the second site. The analyses of organic matter and humic substances indicated that, in Bs horizons, the organic matter characteristics were very similar in the two sites, but in the eluvial and organic horizons marked differences appeared. At the first site, the fulvic acids in the E horizons were small and oxidised, similar therefore to those found in the Bhs horizons, whereas at the second site fulvic acids became bigger, more aliphatic and less oxidised and were therefore less prone to migration. Some of these properties of organic matter were linked to soil water regime, others to the shift in vegetation from forest to grass cover and seemed therefore to be related to the soil evolution itself, being podzolisation in this sense a self-limiting process. Acid precipitation may however have played a role in the change of size of fulvic acids, which were very rich in sulphur, through C–S linkages. The complex interaction between natural and anthropogenic factors seemed to have decreased the ability of organic matter to migrate, enhancing the formation of Histosols.

Eleonora Bonifacio - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of soil organic matter in a limnic Histosol of the alpine morainic system
    Soil Science, 2006
    Co-Authors: Maria Martin, Eleonora Bonifacio, Luisella Celi, Serenella Nardi, Elisabetta Barberis
    Abstract:

    Histosols represent a large carbon reservoir and their preservation is important to limit the emission of CO 2 and the related ecological consequences. In these soils, C storage is governed by waterlogging, bacterial activity, and type of vegetation from which soil organic matter (SOM) originated. In limnic peats, moreover, calcium could play some roles on SOM dynamics. The characteristics of organic fractions composing a Limnic Histosol subjected to intermittent periods of oxidation have been studied to understand the main factors influencing SOM dynamics and accumulation. Soil organic matter was constituted mainly by the unextractable fraction (88.0% of organic C). Dissolved organic matter was in low concentrations (1.30%), formed mainly by undecomposed labile material. Fulvic and humic acids (HAs) were highly humified and rich in O-containing groups, probably because of the periodic oxidizing conditions. Humic acids (concentration, 5.38%), further fractionated by dialysis in three fractions on a molecular weight basis, were constituted mainly by the heaviest fraction (greater than 50 kDa; concentration, 5.36%). Humin was composed of a hydrophobic fraction, derived probably from lipids and waxes, and of a hydrophilic fraction, with features closer to those of HA. Both fractions contained surprisingly large amounts of carboxyl and phenolic groups and trapped a large percentage of Ca, which is unextractable even after strong acid treatments. This suggests that humin was actually formed by smaller molecules that strongly interact with Ca through their polar groups, forming larger aggregates. The large percentage of unextractable organic material and the strong interaction with Ca could preserve SOM from microbial degradation and, hence, limit the mineralization even in the absence of water, preserving a C sink that is presently storing a large amount of C in both organic and carbonate forms.

  • Spodosol-Histosol evolution in the Krkonoše National Park (CZ)
    Geoderma, 2006
    Co-Authors: Eleonora Bonifacio, Stefania Santoni, Luisella Celi, Ermanno Zanini
    Abstract:

    Abstract Podzols often occur in association with organic soils along sequences governed by relief, with peats in depressions and podzols on slopes. The formation of bogs has also been described as a soil-induced process: the formation of cemented pans, impermeable to water, in highly developed podzols, enhanced the accumulation of organic matter and slowed down its decomposition. Humans may interfere with soil development, enhancing acidification and thus the eluvial phase of podzolisation, as it may be in the case of acid precipitation or of the plantation of conifers. The aim of this work was to study the transition between Spodosols and Histosols, in the Krkonose National Park (CZ), where spruce has substituted the natural vegetation and acid precipitation has damaged several areas of the park. The soils were studied at two sites: one site is relatively preserved and soils (Spodosols and Inceptisols) develop on a steep slope. At the other site, a gently undulating mountain summit, Spodosols are associated to Histosols and the forest decline is more severe. Three Spodosols (Humic Haplocryod, Typic Cryaquod, Placic Cryaquod) and a Histosol were selected at the second site, and the soil properties and organic matter dynamics were compared to those of a Typic Haplocryod sampled at the first site. Profile morphology and chemical analyses indicated that podzolisation has been more intense at the second site, probably because of the differences in relief and in the amount of water available for pedogenic processes: a high accumulation of organic matter and thick Bhs horizons were the most striking differences, together with depletion in Fe from eluvial horizons. Moreover a trend in the chemical indicators of podzolisation was appreciated among the profiles sampled at the second site. The analyses of organic matter and humic substances indicated that, in Bs horizons, the organic matter characteristics were very similar in the two sites, but in the eluvial and organic horizons marked differences appeared. At the first site, the fulvic acids in the E horizons were small and oxidised, similar therefore to those found in the Bhs horizons, whereas at the second site fulvic acids became bigger, more aliphatic and less oxidised and were therefore less prone to migration. Some of these properties of organic matter were linked to soil water regime, others to the shift in vegetation from forest to grass cover and seemed therefore to be related to the soil evolution itself, being podzolisation in this sense a self-limiting process. Acid precipitation may however have played a role in the change of size of fulvic acids, which were very rich in sulphur, through C–S linkages. The complex interaction between natural and anthropogenic factors seemed to have decreased the ability of organic matter to migrate, enhancing the formation of Histosols.

  • Spodosol-Histosol evolution in the Krkonoše National Park (CZ)
    Geoderma, 2006
    Co-Authors: Eleonora Bonifacio, Stefania Santoni, Luisella Celi, Ermanno Zanini
    Abstract:

    Abstract Podzols often occur in association with organic soils along sequences governed by relief, with peats in depressions and podzols on slopes. The formation of bogs has also been described as a soil-induced process: the formation of cemented pans, impermeable to water, in highly developed podzols, enhanced the accumulation of organic matter and slowed down its decomposition. Humans may interfere with soil development, enhancing acidification and thus the eluvial phase of podzolisation, as it may be in the case of acid precipitation or of the plantation of conifers. The aim of this work was to study the transition between Spodosols and Histosols, in the Krkonose National Park (CZ), where spruce has substituted the natural vegetation and acid precipitation has damaged several areas of the park. The soils were studied at two sites: one site is relatively preserved and soils (Spodosols and Inceptisols) develop on a steep slope. At the other site, a gently undulating mountain summit, Spodosols are associated to Histosols and the forest decline is more severe. Three Spodosols (Humic Haplocryod, Typic Cryaquod, Placic Cryaquod) and a Histosol were selected at the second site, and the soil properties and organic matter dynamics were compared to those of a Typic Haplocryod sampled at the first site. Profile morphology and chemical analyses indicated that podzolisation has been more intense at the second site, probably because of the differences in relief and in the amount of water available for pedogenic processes: a high accumulation of organic matter and thick Bhs horizons were the most striking differences, together with depletion in Fe from eluvial horizons. Moreover a trend in the chemical indicators of podzolisation was appreciated among the profiles sampled at the second site. The analyses of organic matter and humic substances indicated that, in Bs horizons, the organic matter characteristics were very similar in the two sites, but in the eluvial and organic horizons marked differences appeared. At the first site, the fulvic acids in the E horizons were small and oxidised, similar therefore to those found in the Bhs horizons, whereas at the second site fulvic acids became bigger, more aliphatic and less oxidised and were therefore less prone to migration. Some of these properties of organic matter were linked to soil water regime, others to the shift in vegetation from forest to grass cover and seemed therefore to be related to the soil evolution itself, being podzolisation in this sense a self-limiting process. Acid precipitation may however have played a role in the change of size of fulvic acids, which were very rich in sulphur, through C–S linkages. The complex interaction between natural and anthropogenic factors seemed to have decreased the ability of organic matter to migrate, enhancing the formation of Histosols.

Luisella Celi - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of soil organic matter in a limnic Histosol of the alpine morainic system
    Soil Science, 2006
    Co-Authors: Maria Martin, Eleonora Bonifacio, Luisella Celi, Serenella Nardi, Elisabetta Barberis
    Abstract:

    Histosols represent a large carbon reservoir and their preservation is important to limit the emission of CO 2 and the related ecological consequences. In these soils, C storage is governed by waterlogging, bacterial activity, and type of vegetation from which soil organic matter (SOM) originated. In limnic peats, moreover, calcium could play some roles on SOM dynamics. The characteristics of organic fractions composing a Limnic Histosol subjected to intermittent periods of oxidation have been studied to understand the main factors influencing SOM dynamics and accumulation. Soil organic matter was constituted mainly by the unextractable fraction (88.0% of organic C). Dissolved organic matter was in low concentrations (1.30%), formed mainly by undecomposed labile material. Fulvic and humic acids (HAs) were highly humified and rich in O-containing groups, probably because of the periodic oxidizing conditions. Humic acids (concentration, 5.38%), further fractionated by dialysis in three fractions on a molecular weight basis, were constituted mainly by the heaviest fraction (greater than 50 kDa; concentration, 5.36%). Humin was composed of a hydrophobic fraction, derived probably from lipids and waxes, and of a hydrophilic fraction, with features closer to those of HA. Both fractions contained surprisingly large amounts of carboxyl and phenolic groups and trapped a large percentage of Ca, which is unextractable even after strong acid treatments. This suggests that humin was actually formed by smaller molecules that strongly interact with Ca through their polar groups, forming larger aggregates. The large percentage of unextractable organic material and the strong interaction with Ca could preserve SOM from microbial degradation and, hence, limit the mineralization even in the absence of water, preserving a C sink that is presently storing a large amount of C in both organic and carbonate forms.

  • Spodosol-Histosol evolution in the Krkonoše National Park (CZ)
    Geoderma, 2006
    Co-Authors: Eleonora Bonifacio, Stefania Santoni, Luisella Celi, Ermanno Zanini
    Abstract:

    Abstract Podzols often occur in association with organic soils along sequences governed by relief, with peats in depressions and podzols on slopes. The formation of bogs has also been described as a soil-induced process: the formation of cemented pans, impermeable to water, in highly developed podzols, enhanced the accumulation of organic matter and slowed down its decomposition. Humans may interfere with soil development, enhancing acidification and thus the eluvial phase of podzolisation, as it may be in the case of acid precipitation or of the plantation of conifers. The aim of this work was to study the transition between Spodosols and Histosols, in the Krkonose National Park (CZ), where spruce has substituted the natural vegetation and acid precipitation has damaged several areas of the park. The soils were studied at two sites: one site is relatively preserved and soils (Spodosols and Inceptisols) develop on a steep slope. At the other site, a gently undulating mountain summit, Spodosols are associated to Histosols and the forest decline is more severe. Three Spodosols (Humic Haplocryod, Typic Cryaquod, Placic Cryaquod) and a Histosol were selected at the second site, and the soil properties and organic matter dynamics were compared to those of a Typic Haplocryod sampled at the first site. Profile morphology and chemical analyses indicated that podzolisation has been more intense at the second site, probably because of the differences in relief and in the amount of water available for pedogenic processes: a high accumulation of organic matter and thick Bhs horizons were the most striking differences, together with depletion in Fe from eluvial horizons. Moreover a trend in the chemical indicators of podzolisation was appreciated among the profiles sampled at the second site. The analyses of organic matter and humic substances indicated that, in Bs horizons, the organic matter characteristics were very similar in the two sites, but in the eluvial and organic horizons marked differences appeared. At the first site, the fulvic acids in the E horizons were small and oxidised, similar therefore to those found in the Bhs horizons, whereas at the second site fulvic acids became bigger, more aliphatic and less oxidised and were therefore less prone to migration. Some of these properties of organic matter were linked to soil water regime, others to the shift in vegetation from forest to grass cover and seemed therefore to be related to the soil evolution itself, being podzolisation in this sense a self-limiting process. Acid precipitation may however have played a role in the change of size of fulvic acids, which were very rich in sulphur, through C–S linkages. The complex interaction between natural and anthropogenic factors seemed to have decreased the ability of organic matter to migrate, enhancing the formation of Histosols.

  • Spodosol-Histosol evolution in the Krkonoše National Park (CZ)
    Geoderma, 2006
    Co-Authors: Eleonora Bonifacio, Stefania Santoni, Luisella Celi, Ermanno Zanini
    Abstract:

    Abstract Podzols often occur in association with organic soils along sequences governed by relief, with peats in depressions and podzols on slopes. The formation of bogs has also been described as a soil-induced process: the formation of cemented pans, impermeable to water, in highly developed podzols, enhanced the accumulation of organic matter and slowed down its decomposition. Humans may interfere with soil development, enhancing acidification and thus the eluvial phase of podzolisation, as it may be in the case of acid precipitation or of the plantation of conifers. The aim of this work was to study the transition between Spodosols and Histosols, in the Krkonose National Park (CZ), where spruce has substituted the natural vegetation and acid precipitation has damaged several areas of the park. The soils were studied at two sites: one site is relatively preserved and soils (Spodosols and Inceptisols) develop on a steep slope. At the other site, a gently undulating mountain summit, Spodosols are associated to Histosols and the forest decline is more severe. Three Spodosols (Humic Haplocryod, Typic Cryaquod, Placic Cryaquod) and a Histosol were selected at the second site, and the soil properties and organic matter dynamics were compared to those of a Typic Haplocryod sampled at the first site. Profile morphology and chemical analyses indicated that podzolisation has been more intense at the second site, probably because of the differences in relief and in the amount of water available for pedogenic processes: a high accumulation of organic matter and thick Bhs horizons were the most striking differences, together with depletion in Fe from eluvial horizons. Moreover a trend in the chemical indicators of podzolisation was appreciated among the profiles sampled at the second site. The analyses of organic matter and humic substances indicated that, in Bs horizons, the organic matter characteristics were very similar in the two sites, but in the eluvial and organic horizons marked differences appeared. At the first site, the fulvic acids in the E horizons were small and oxidised, similar therefore to those found in the Bhs horizons, whereas at the second site fulvic acids became bigger, more aliphatic and less oxidised and were therefore less prone to migration. Some of these properties of organic matter were linked to soil water regime, others to the shift in vegetation from forest to grass cover and seemed therefore to be related to the soil evolution itself, being podzolisation in this sense a self-limiting process. Acid precipitation may however have played a role in the change of size of fulvic acids, which were very rich in sulphur, through C–S linkages. The complex interaction between natural and anthropogenic factors seemed to have decreased the ability of organic matter to migrate, enhancing the formation of Histosols.

Pascal Froidevaux - One of the best experts on this subject based on the ideXlab platform.

  • Origin and stability of uranium accumulation-layers in an Alpine Histosol.
    The Science of the total environment, 2020
    Co-Authors: Jasquelin Peña, Marietta Straub, Virginie Flury, Eymerick Loup, José Corcho, Philipp Steinmann, François O. Bochud, Pascal Froidevaux
    Abstract:

    Uranium (U) accumulation in organic soils is a common phenomenon that can lead to high U concentration in montane wetlands. The stability of the immobilized U in natural wetlands following redox fluctuations and re-oxidation events, however, is not currently known. In this study, we investigated a saturated Histosol that had accumulated up to 6000 ppm of U at 30 cm below ground level (bgl). Uranium in the waters feeding the wetland originates from the weathering of surrounding gneiss rocks, a process releasing trace amounts (