The Experts below are selected from a list of 1536 Experts worldwide ranked by ideXlab platform

Norbert Bischoff - One of the best experts on this subject based on the ideXlab platform.

  • interactive effects of land use and climate on soil organic carbon storage in western siberian Steppe Soils
    2020
    Co-Authors: Norbert Bischoff, Olga Shibistova, Alexander Puzanov, Georg Guggenberger, Christoph Muller, S Rolinski, A V Prishchepov, F Schierhorn
    Abstract:

    Soils store much more carbon (C) than all terrestrial plants and the Earth’s atmosphere together, and the C exchange between Soils and atmosphere largely influences the CO2 contents in the atmosphere. While converting native ecosystems into agricultural land in the past caused a huge historical release of C into the atmosphere, an optimization of the management of agricultural Soils offers the possibility of restoring parts of the previously lost C in the soil. However, in this respect, interrelationships of land use and soil management with climate change must be considered. In this chapter, land use and climatic effects on soil organic carbon (SOC) stocks in the large western Siberian grasslands will be evaluated and scenarios of future development of SOC storage will be given. A combination of soil analysis along a climatic gradient from the forest Steppe to the dry Steppe and a modelling approach with the Lund–Potsdam–Jena managed Land (LPJmL) model revealed, that since their cultivation Soils of the Kulunda Steppe lost about 20–35% of their organic C. Surprisingly, not only particulate organic C was affected but likewise also organic C located within mineral-organic associations was lost, and the proportion of the lost C is independent from the climatic conditions. Parts of this lost organic C can be restored by abandoning arable land. However, due to political and economic constraints, this does not seem to be likely. Minimum or zero tillage may provide an option to increase the organic C storage in western Siberian Steppe Soils, but the potential effect may be limited. The LPJmL model simulates a continuing climate-change driven C loss from soil, which corroborates results of soil analysis along the climatic gradient. The management of SOC stock has to be evaluated also for its effect on soil erosion, water deficiency and nutrient shortage.

  • limited protection of macro aggregate occluded organic carbon in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Georg Guggenberger
    Abstract:

    Abstract. Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian Steppe Soils, we determined OC mineralization rates of intact (250–2000 µm) and crushed (

  • organic matter dynamics along a salinity gradient in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    Abstract. Salt-affected Soils will become more frequent in the next decades as arid and semiarid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is crucial for soil fertility and represents an important carbon sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in the Soils of the southwestern Siberian Kulunda Steppe (Kastanozem, non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes ( δ13 C, 14 C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Aboveground biomass was measured as a proxy for plant growth and soil OC inputs. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks compared to non-salt-affected Kastanozems, (iii) sodicity reduces the proportion and stability of mineral-associated OM, and (iv) the fungi : bacteria ratio is negatively correlated with salinity. Against our first hypothesis, OC stocks increased along the salinity gradient with the most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only  10 % in all three soil types, while mineral-associated OM contributed >  90 %. Isotopic data ( δ13 C, 14 C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient and that particulate OM was not more persistent under saline conditions. Our third hypothesis was also rejected, as Sodic Solonchaks contained more than twice as much mineral-bound OC than the Kastanozems, which we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. Contrary to the fourth hypothesis, the fungi : bacteria ratio in the topSoils remained fairly constant along the salinity gradient. A possible explanation for why our hypotheses were not affirmed is that soil moisture covaried with salinity along the transect, i.e., the Solonchaks were generally wetter than the Kastanozems. This might cause comparable water stress conditions for plants and microorganisms, either due to a low osmotic or a low matric potential and resulting in (i) similar plant growth and hence soil OC inputs along the transect, (ii) a comparable persistence of particulate OM, and (iii) unaffected fungi : bacteria ratios. We conclude that salt-affected Soils contribute significantly to the OC storage in the semiarid Soils of the Kulunda Steppe, while most of the OC is associated with minerals and is therefore effectively sequestered in the long term.

  • Organic matter dynamics along a salinity gradient in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    <p><strong>Abstract.</strong> Salt-affected Soils will become increasingly important in the next decades as arid and semi-arid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is largely controlling soil fertility and represents an important C sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in Soils of the south-western Siberian Kulunda Steppe (Kastanozem, Non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes (δ<sup>13</sup>C, <sup>14</sup>C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks as compared to non-salt-affected Kastanozems, and (iii) sodicity reduces the proportion and stability of mineral-associated OM. Against our first hypothesis, OC stocks increased along the salinity gradient with most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only < 10 % in all three soil types, while mineral-associated OM contributed to > 90 %. Isotopic data (δ<sup>13</sup>C, <sup>14</sup>C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient, thus particulate OM was not more persistent under saline conditions. This we attribute to a resilient microbial community composition and function, which was nearly unaffected by salt occurrence, and capable of decomposing OM at a similar rate in salt-affected and non-salt-affected Soils. Also our third hypothesis was rejected, as saline-sodic Soils contained more than twice as much mineral-bound OC than non-salt-affected Soils, what we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. We conclude that salt-affected Soils contribute significantly to the OC storage in the semi-arid Soils of the Kulunda Steppe while most of the OC is associated to minerals and therefore effectively sequestered in the long-term.</p>

  • Limited protection of macro-aggregate occluded organic carbon in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Roland Fuß, Georg Guggenberger
    Abstract:

    <p><strong>Abstract.</strong> Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal time scale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in south-western Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate protected OC under different land-use and as function of land-use duration and intensity in Siberian Steppe Soils, we determined OC mineralization rates of intact (25–2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda Steppe. Additionally we incubated bulk soil (< 2000 µm) to determine the effect of land-use change (LUC) and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable Soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land-use duration and intensity increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land-use regimes. Macro-aggregate protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to maximally 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by the duration and intensity of land-use. However, mean residence times of the fast and slow OC pool tended to become shorter along one chronosequence. We conclude, that the tillage-induced break-down of macro-aggregates has not reduced the OC contents in the Soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.</p>

Olga Shibistova - One of the best experts on this subject based on the ideXlab platform.

  • interactive effects of land use and climate on soil organic carbon storage in western siberian Steppe Soils
    2020
    Co-Authors: Norbert Bischoff, Olga Shibistova, Alexander Puzanov, Georg Guggenberger, Christoph Muller, S Rolinski, A V Prishchepov, F Schierhorn
    Abstract:

    Soils store much more carbon (C) than all terrestrial plants and the Earth’s atmosphere together, and the C exchange between Soils and atmosphere largely influences the CO2 contents in the atmosphere. While converting native ecosystems into agricultural land in the past caused a huge historical release of C into the atmosphere, an optimization of the management of agricultural Soils offers the possibility of restoring parts of the previously lost C in the soil. However, in this respect, interrelationships of land use and soil management with climate change must be considered. In this chapter, land use and climatic effects on soil organic carbon (SOC) stocks in the large western Siberian grasslands will be evaluated and scenarios of future development of SOC storage will be given. A combination of soil analysis along a climatic gradient from the forest Steppe to the dry Steppe and a modelling approach with the Lund–Potsdam–Jena managed Land (LPJmL) model revealed, that since their cultivation Soils of the Kulunda Steppe lost about 20–35% of their organic C. Surprisingly, not only particulate organic C was affected but likewise also organic C located within mineral-organic associations was lost, and the proportion of the lost C is independent from the climatic conditions. Parts of this lost organic C can be restored by abandoning arable land. However, due to political and economic constraints, this does not seem to be likely. Minimum or zero tillage may provide an option to increase the organic C storage in western Siberian Steppe Soils, but the potential effect may be limited. The LPJmL model simulates a continuing climate-change driven C loss from soil, which corroborates results of soil analysis along the climatic gradient. The management of SOC stock has to be evaluated also for its effect on soil erosion, water deficiency and nutrient shortage.

  • limited protection of macro aggregate occluded organic carbon in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Georg Guggenberger
    Abstract:

    Abstract. Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian Steppe Soils, we determined OC mineralization rates of intact (250–2000 µm) and crushed (

  • organic matter dynamics along a salinity gradient in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    Abstract. Salt-affected Soils will become more frequent in the next decades as arid and semiarid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is crucial for soil fertility and represents an important carbon sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in the Soils of the southwestern Siberian Kulunda Steppe (Kastanozem, non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes ( δ13 C, 14 C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Aboveground biomass was measured as a proxy for plant growth and soil OC inputs. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks compared to non-salt-affected Kastanozems, (iii) sodicity reduces the proportion and stability of mineral-associated OM, and (iv) the fungi : bacteria ratio is negatively correlated with salinity. Against our first hypothesis, OC stocks increased along the salinity gradient with the most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only  10 % in all three soil types, while mineral-associated OM contributed >  90 %. Isotopic data ( δ13 C, 14 C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient and that particulate OM was not more persistent under saline conditions. Our third hypothesis was also rejected, as Sodic Solonchaks contained more than twice as much mineral-bound OC than the Kastanozems, which we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. Contrary to the fourth hypothesis, the fungi : bacteria ratio in the topSoils remained fairly constant along the salinity gradient. A possible explanation for why our hypotheses were not affirmed is that soil moisture covaried with salinity along the transect, i.e., the Solonchaks were generally wetter than the Kastanozems. This might cause comparable water stress conditions for plants and microorganisms, either due to a low osmotic or a low matric potential and resulting in (i) similar plant growth and hence soil OC inputs along the transect, (ii) a comparable persistence of particulate OM, and (iii) unaffected fungi : bacteria ratios. We conclude that salt-affected Soils contribute significantly to the OC storage in the semiarid Soils of the Kulunda Steppe, while most of the OC is associated with minerals and is therefore effectively sequestered in the long term.

  • Organic matter dynamics along a salinity gradient in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    <p><strong>Abstract.</strong> Salt-affected Soils will become increasingly important in the next decades as arid and semi-arid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is largely controlling soil fertility and represents an important C sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in Soils of the south-western Siberian Kulunda Steppe (Kastanozem, Non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes (δ<sup>13</sup>C, <sup>14</sup>C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks as compared to non-salt-affected Kastanozems, and (iii) sodicity reduces the proportion and stability of mineral-associated OM. Against our first hypothesis, OC stocks increased along the salinity gradient with most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only < 10 % in all three soil types, while mineral-associated OM contributed to > 90 %. Isotopic data (δ<sup>13</sup>C, <sup>14</sup>C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient, thus particulate OM was not more persistent under saline conditions. This we attribute to a resilient microbial community composition and function, which was nearly unaffected by salt occurrence, and capable of decomposing OM at a similar rate in salt-affected and non-salt-affected Soils. Also our third hypothesis was rejected, as saline-sodic Soils contained more than twice as much mineral-bound OC than non-salt-affected Soils, what we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. We conclude that salt-affected Soils contribute significantly to the OC storage in the semi-arid Soils of the Kulunda Steppe while most of the OC is associated to minerals and therefore effectively sequestered in the long-term.</p>

  • Limited protection of macro-aggregate occluded organic carbon in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Roland Fuß, Georg Guggenberger
    Abstract:

    <p><strong>Abstract.</strong> Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal time scale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in south-western Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate protected OC under different land-use and as function of land-use duration and intensity in Siberian Steppe Soils, we determined OC mineralization rates of intact (25–2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda Steppe. Additionally we incubated bulk soil (< 2000 µm) to determine the effect of land-use change (LUC) and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable Soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land-use duration and intensity increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land-use regimes. Macro-aggregate protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to maximally 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by the duration and intensity of land-use. However, mean residence times of the fast and slow OC pool tended to become shorter along one chronosequence. We conclude, that the tillage-induced break-down of macro-aggregates has not reduced the OC contents in the Soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.</p>

Anna Grebennikova - One of the best experts on this subject based on the ideXlab platform.

  • limited protection of macro aggregate occluded organic carbon in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Georg Guggenberger
    Abstract:

    Abstract. Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian Steppe Soils, we determined OC mineralization rates of intact (250–2000 µm) and crushed (

  • organic matter dynamics along a salinity gradient in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    Abstract. Salt-affected Soils will become more frequent in the next decades as arid and semiarid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is crucial for soil fertility and represents an important carbon sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in the Soils of the southwestern Siberian Kulunda Steppe (Kastanozem, non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes ( δ13 C, 14 C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Aboveground biomass was measured as a proxy for plant growth and soil OC inputs. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks compared to non-salt-affected Kastanozems, (iii) sodicity reduces the proportion and stability of mineral-associated OM, and (iv) the fungi : bacteria ratio is negatively correlated with salinity. Against our first hypothesis, OC stocks increased along the salinity gradient with the most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only  10 % in all three soil types, while mineral-associated OM contributed >  90 %. Isotopic data ( δ13 C, 14 C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient and that particulate OM was not more persistent under saline conditions. Our third hypothesis was also rejected, as Sodic Solonchaks contained more than twice as much mineral-bound OC than the Kastanozems, which we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. Contrary to the fourth hypothesis, the fungi : bacteria ratio in the topSoils remained fairly constant along the salinity gradient. A possible explanation for why our hypotheses were not affirmed is that soil moisture covaried with salinity along the transect, i.e., the Solonchaks were generally wetter than the Kastanozems. This might cause comparable water stress conditions for plants and microorganisms, either due to a low osmotic or a low matric potential and resulting in (i) similar plant growth and hence soil OC inputs along the transect, (ii) a comparable persistence of particulate OM, and (iii) unaffected fungi : bacteria ratios. We conclude that salt-affected Soils contribute significantly to the OC storage in the semiarid Soils of the Kulunda Steppe, while most of the OC is associated with minerals and is therefore effectively sequestered in the long term.

  • Organic matter dynamics along a salinity gradient in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    <p><strong>Abstract.</strong> Salt-affected Soils will become increasingly important in the next decades as arid and semi-arid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is largely controlling soil fertility and represents an important C sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in Soils of the south-western Siberian Kulunda Steppe (Kastanozem, Non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes (δ<sup>13</sup>C, <sup>14</sup>C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks as compared to non-salt-affected Kastanozems, and (iii) sodicity reduces the proportion and stability of mineral-associated OM. Against our first hypothesis, OC stocks increased along the salinity gradient with most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only < 10 % in all three soil types, while mineral-associated OM contributed to > 90 %. Isotopic data (δ<sup>13</sup>C, <sup>14</sup>C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient, thus particulate OM was not more persistent under saline conditions. This we attribute to a resilient microbial community composition and function, which was nearly unaffected by salt occurrence, and capable of decomposing OM at a similar rate in salt-affected and non-salt-affected Soils. Also our third hypothesis was rejected, as saline-sodic Soils contained more than twice as much mineral-bound OC than non-salt-affected Soils, what we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. We conclude that salt-affected Soils contribute significantly to the OC storage in the semi-arid Soils of the Kulunda Steppe while most of the OC is associated to minerals and therefore effectively sequestered in the long-term.</p>

  • Limited protection of macro-aggregate occluded organic carbon in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Roland Fuß, Georg Guggenberger
    Abstract:

    <p><strong>Abstract.</strong> Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal time scale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in south-western Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate protected OC under different land-use and as function of land-use duration and intensity in Siberian Steppe Soils, we determined OC mineralization rates of intact (25–2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda Steppe. Additionally we incubated bulk soil (< 2000 µm) to determine the effect of land-use change (LUC) and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable Soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land-use duration and intensity increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land-use regimes. Macro-aggregate protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to maximally 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by the duration and intensity of land-use. However, mean residence times of the fast and slow OC pool tended to become shorter along one chronosequence. We conclude, that the tillage-induced break-down of macro-aggregates has not reduced the OC contents in the Soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.</p>

  • land use change under different climatic conditions consequences for organic matter and microbial communities in siberian Steppe Soils
    Agriculture Ecosystems & Environment, 2016
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Evgeny Reichert, Frank Schaarschmidt, Steffen Heinicke
    Abstract:

    Abstract The Kulunda Steppe is part of the greatest conversion areas of the world where 420,000 km2 grassland have been converted into cropland between 1954 and 1963. However, little is known about the recent and future impacts of land-use change (LUC) on soil organic carbon (OC) dynamics in Siberian Steppe Soils under various climatic conditions. By investigating grassland vs. cropland Soils along a climatic gradient from forest to typical to dry Steppe types of the Kulunda Steppe, our study aimed to (i) quantify the change of OC stocks (0–60 cm) after LUC from grassland to cropland as function of climate, (ii) elucidate the concurrent effects on aggregate stability and different functional soil organic matter (OM) fractions (particulate vs. mineral-bound OM), and (iii) assess climate- and LUC-induced changes in the microbial community composition and the contribution of fungi to aggregate stability based on phospholipid fatty acid (PLFA) profiles. Soil OC stocks decreased from the forest Steppe (grassland: 218 ± 17 Mg ha−1) over the typical Steppe (153 ± 10 Mg ha−1) to the dry Steppe (134 ± 11 Mg ha−1). Across all climatic regimes, LUC caused similar OC losses of 31% (95% confidence interval: 17–43%) in 0–25 cm depth and a concurrent decline in aggregate stability, which was not related to the amount of fungal PLFA. Density fractionation revealed that the largest part of soil OM (>90% of total OC) was associated with minerals and

Alexander Puzanov - One of the best experts on this subject based on the ideXlab platform.

  • interactive effects of land use and climate on soil organic carbon storage in western siberian Steppe Soils
    2020
    Co-Authors: Norbert Bischoff, Olga Shibistova, Alexander Puzanov, Georg Guggenberger, Christoph Muller, S Rolinski, A V Prishchepov, F Schierhorn
    Abstract:

    Soils store much more carbon (C) than all terrestrial plants and the Earth’s atmosphere together, and the C exchange between Soils and atmosphere largely influences the CO2 contents in the atmosphere. While converting native ecosystems into agricultural land in the past caused a huge historical release of C into the atmosphere, an optimization of the management of agricultural Soils offers the possibility of restoring parts of the previously lost C in the soil. However, in this respect, interrelationships of land use and soil management with climate change must be considered. In this chapter, land use and climatic effects on soil organic carbon (SOC) stocks in the large western Siberian grasslands will be evaluated and scenarios of future development of SOC storage will be given. A combination of soil analysis along a climatic gradient from the forest Steppe to the dry Steppe and a modelling approach with the Lund–Potsdam–Jena managed Land (LPJmL) model revealed, that since their cultivation Soils of the Kulunda Steppe lost about 20–35% of their organic C. Surprisingly, not only particulate organic C was affected but likewise also organic C located within mineral-organic associations was lost, and the proportion of the lost C is independent from the climatic conditions. Parts of this lost organic C can be restored by abandoning arable land. However, due to political and economic constraints, this does not seem to be likely. Minimum or zero tillage may provide an option to increase the organic C storage in western Siberian Steppe Soils, but the potential effect may be limited. The LPJmL model simulates a continuing climate-change driven C loss from soil, which corroborates results of soil analysis along the climatic gradient. The management of SOC stock has to be evaluated also for its effect on soil erosion, water deficiency and nutrient shortage.

  • limited protection of macro aggregate occluded organic carbon in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Georg Guggenberger
    Abstract:

    Abstract. Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian Steppe Soils, we determined OC mineralization rates of intact (250–2000 µm) and crushed (

  • organic matter dynamics along a salinity gradient in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    Abstract. Salt-affected Soils will become more frequent in the next decades as arid and semiarid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is crucial for soil fertility and represents an important carbon sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in the Soils of the southwestern Siberian Kulunda Steppe (Kastanozem, non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes ( δ13 C, 14 C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Aboveground biomass was measured as a proxy for plant growth and soil OC inputs. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks compared to non-salt-affected Kastanozems, (iii) sodicity reduces the proportion and stability of mineral-associated OM, and (iv) the fungi : bacteria ratio is negatively correlated with salinity. Against our first hypothesis, OC stocks increased along the salinity gradient with the most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only  10 % in all three soil types, while mineral-associated OM contributed >  90 %. Isotopic data ( δ13 C, 14 C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient and that particulate OM was not more persistent under saline conditions. Our third hypothesis was also rejected, as Sodic Solonchaks contained more than twice as much mineral-bound OC than the Kastanozems, which we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. Contrary to the fourth hypothesis, the fungi : bacteria ratio in the topSoils remained fairly constant along the salinity gradient. A possible explanation for why our hypotheses were not affirmed is that soil moisture covaried with salinity along the transect, i.e., the Solonchaks were generally wetter than the Kastanozems. This might cause comparable water stress conditions for plants and microorganisms, either due to a low osmotic or a low matric potential and resulting in (i) similar plant growth and hence soil OC inputs along the transect, (ii) a comparable persistence of particulate OM, and (iii) unaffected fungi : bacteria ratios. We conclude that salt-affected Soils contribute significantly to the OC storage in the semiarid Soils of the Kulunda Steppe, while most of the OC is associated with minerals and is therefore effectively sequestered in the long term.

  • Organic matter dynamics along a salinity gradient in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Reiner Dohrmann, Daniel Herdtle, Lukas Gerhard, Franziska Fritzsche, Anna Grebennikova
    Abstract:

    <p><strong>Abstract.</strong> Salt-affected Soils will become increasingly important in the next decades as arid and semi-arid ecosystems are predicted to expand as a result of climate change. Nevertheless, little is known about organic matter (OM) dynamics in these Soils, though OM is largely controlling soil fertility and represents an important C sink. We aimed at investigating OM dynamics along a salinity and sodicity gradient in Soils of the south-western Siberian Kulunda Steppe (Kastanozem, Non-sodic Solonchak, Sodic Solonchak) by assessing the organic carbon (OC) stocks, the quantity and quality of particulate and mineral-associated OM in terms of non-cellulosic neutral sugar contents and carbon isotopes (δ<sup>13</sup>C, <sup>14</sup>C activity), and the microbial community composition based on phospholipid fatty acid (PLFA) patterns. Our hypotheses were that (i) soil OC stocks decrease along the salinity gradient, (ii) the proportion and stability of particulate OM is larger in salt-affected Solonchaks as compared to non-salt-affected Kastanozems, and (iii) sodicity reduces the proportion and stability of mineral-associated OM. Against our first hypothesis, OC stocks increased along the salinity gradient with most pronounced differences between topSoils. In contrast to our second hypothesis, the proportion of particulate OM was unaffected by salinity, thereby accounting for only < 10 % in all three soil types, while mineral-associated OM contributed to > 90 %. Isotopic data (δ<sup>13</sup>C, <sup>14</sup>C activity) and neutral sugars in the OM fractions indicated a comparable degree of OM transformation along the salinity gradient, thus particulate OM was not more persistent under saline conditions. This we attribute to a resilient microbial community composition and function, which was nearly unaffected by salt occurrence, and capable of decomposing OM at a similar rate in salt-affected and non-salt-affected Soils. Also our third hypothesis was rejected, as saline-sodic Soils contained more than twice as much mineral-bound OC than non-salt-affected Soils, what we ascribe to the flocculation of OM and mineral components under higher ionic strength conditions. We conclude that salt-affected Soils contribute significantly to the OC storage in the semi-arid Soils of the Kulunda Steppe while most of the OC is associated to minerals and therefore effectively sequestered in the long-term.</p>

  • Limited protection of macro-aggregate occluded organic carbon in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Roland Fuß, Georg Guggenberger
    Abstract:

    <p><strong>Abstract.</strong> Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal time scale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in south-western Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate protected OC under different land-use and as function of land-use duration and intensity in Siberian Steppe Soils, we determined OC mineralization rates of intact (25–2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda Steppe. Additionally we incubated bulk soil (< 2000 µm) to determine the effect of land-use change (LUC) and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable Soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land-use duration and intensity increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land-use regimes. Macro-aggregate protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to maximally 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by the duration and intensity of land-use. However, mean residence times of the fast and slow OC pool tended to become shorter along one chronosequence. We conclude, that the tillage-induced break-down of macro-aggregates has not reduced the OC contents in the Soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.</p>

Georg Guggenberger - One of the best experts on this subject based on the ideXlab platform.

  • interactive effects of land use and climate on soil organic carbon storage in western siberian Steppe Soils
    2020
    Co-Authors: Norbert Bischoff, Olga Shibistova, Alexander Puzanov, Georg Guggenberger, Christoph Muller, S Rolinski, A V Prishchepov, F Schierhorn
    Abstract:

    Soils store much more carbon (C) than all terrestrial plants and the Earth’s atmosphere together, and the C exchange between Soils and atmosphere largely influences the CO2 contents in the atmosphere. While converting native ecosystems into agricultural land in the past caused a huge historical release of C into the atmosphere, an optimization of the management of agricultural Soils offers the possibility of restoring parts of the previously lost C in the soil. However, in this respect, interrelationships of land use and soil management with climate change must be considered. In this chapter, land use and climatic effects on soil organic carbon (SOC) stocks in the large western Siberian grasslands will be evaluated and scenarios of future development of SOC storage will be given. A combination of soil analysis along a climatic gradient from the forest Steppe to the dry Steppe and a modelling approach with the Lund–Potsdam–Jena managed Land (LPJmL) model revealed, that since their cultivation Soils of the Kulunda Steppe lost about 20–35% of their organic C. Surprisingly, not only particulate organic C was affected but likewise also organic C located within mineral-organic associations was lost, and the proportion of the lost C is independent from the climatic conditions. Parts of this lost organic C can be restored by abandoning arable land. However, due to political and economic constraints, this does not seem to be likely. Minimum or zero tillage may provide an option to increase the organic C storage in western Siberian Steppe Soils, but the potential effect may be limited. The LPJmL model simulates a continuing climate-change driven C loss from soil, which corroborates results of soil analysis along the climatic gradient. The management of SOC stock has to be evaluated also for its effect on soil erosion, water deficiency and nutrient shortage.

  • limited protection of macro aggregate occluded organic carbon in siberian Steppe Soils
    Biogeosciences, 2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Georg Guggenberger
    Abstract:

    Abstract. Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal timescale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in southwestern Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate-protected OC under different land use as function of land use intensity and time since land use change (LUC) from pasture to arable land in Siberian Steppe Soils, we determined OC mineralization rates of intact (250–2000 µm) and crushed (

  • Limited protection of macro-aggregate occluded organic carbon in Siberian Steppe Soils
    2017
    Co-Authors: Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Roland Fuß, Georg Guggenberger
    Abstract:

    <p><strong>Abstract.</strong> Macro-aggregates especially in agricultural Steppe Soils are supposed to play a vital role for soil organic carbon (OC) stabilization at a decadal time scale. While most research on soil OC stabilization in Steppes focused on North American prairie Soils of the Great Plains with information mainly provided by short-term incubation experiments, little is known about the agricultural Steppes in south-western Siberia, though they belong to the greatest conversion areas in the world and occupy an area larger than that in the Great Plains. To quantify the proportion of macro-aggregate protected OC under different land-use and as function of land-use duration and intensity in Siberian Steppe Soils, we determined OC mineralization rates of intact (25–2000 µm) and crushed (< 250 µm) macro-aggregates in long-term incubations over 401 days (20 °C; 60 % water holding capacity) along two agricultural chronosequences in the Siberian Kulunda Steppe. Additionally we incubated bulk soil (< 2000 µm) to determine the effect of land-use change (LUC) and subsequent agricultural use on a fast and a slow soil OC pool (labile vs. more stable OC), as derived from fitting exponential decay models to incubation data. We hypothesized that (i) macro-aggregate crushing leads to increased OC mineralization due to an increasing microbial accessibility of a previously occluded labile macro-aggregate OC fraction, and (ii) bulk soil OC mineralization rates and the size of the fast OC pool are higher in pasture than in arable Soils with decreasing bulk soil OC mineralization rates and size of the fast OC pool as land-use duration and intensity increase. Against our hypothesis, OC mineralization rates of crushed macro-aggregates were similar to those of intact macro-aggregates under all land-use regimes. Macro-aggregate protected OC was almost absent and accounted for < 1 % of the total macro-aggregate OC content and to maximally 8 ± 4 % of mineralized OC. In accordance to our second hypothesis, highest bulk soil OC mineralization rates and sizes of the fast OC pool were determined under pasture, but mineralization rates and pool sizes were unaffected by the duration and intensity of land-use. However, mean residence times of the fast and slow OC pool tended to become shorter along one chronosequence. We conclude, that the tillage-induced break-down of macro-aggregates has not reduced the OC contents in the Soils under study. The decline of OC after LUC is probably attributed to the faster soil OC turnover under arable land as compared to pasture at a reduced plant residue input.</p>