The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Gerhard Soja - One of the best experts on this subject based on the ideXlab platform.

  • Changes in biochar physical and chemical properties: Accelerated biochar aging in an acidic soil
    Carbon, 2017
    Co-Authors: Maria V. Rechberger, Stefanie Kloss, Gerhard Soja, Harald Rennhofer, Johannes Tintner, Andrea Watzinger, Helga C. Lichtenegger, Franz Zehetner
    Abstract:

    Biochar (BC) is increasingly used as soil amendment; however, its stability and alteration in the soil environment are still unclear. Here, we investigated BC decomposition and changes of BC characteristics during a long-term incubation experiment. 13C-depleted BCs were incubated for two years in an acidic Planosol and a calcareous Chernozem, respectively. BC decomposition inferred from the C isotope signature of the incubated materials was marginal. Yet, small angle X-ray scattering showed that the surface roughness of the BCs increased over time. Mid-infrared spectra indicated changes in the BCs' molecular characteristics upon aging. There was an overall increase of infrared bands assigned to H- and O-containing functional groups, especially carboxylic groups. Contact angle measurements revealed that the hydrophobic surfaces of freshly produced BCs became more hydrophilic during soil incubation. Our results suggest that BC aging is strongly influenced by soil traits. In the more acidic Planosol, these aging processes were accelerated.

  • Long-term effects of biochar on soil physical properties
    Geoderma, 2016
    Co-Authors: Leigh D. Burrell, Nicola Rampazzo, Franz Zehetner, Bernhard Wimmer, Gerhard Soja
    Abstract:

    A growing body of research into the effects of biochar on soil physical characteristics suggests that it is most effective in coarse-textured soils. In this study, we set out to test this theory by comparing the effects of a woodchip biochar on a Chernozem, Cambisol and a coarse-textured Planosol in a pot experiment. We also compared the effect of different biochars on the Planosol, including woodchip biochar, straw biochar, and two vineyard-pruning biochars produced at different pyrolysis temperatures. Three characteristics were measured as indicators of good soil structure: bulk density, soil aggregate stability and plant available water. The woodchip biochar induced greater decreases in bulk density in the coarse textured Planosol than in the other soils. It also had a greater effect on soil aggregate stability in the Planosol than in the Cambisol, but had no effect on the Chernozem. Woodchip biochar had no effect on plant available water in any of the three soils. Straw biochar was the most effective at improving soil aggregate stability in the coarse-textured Planosol, with a 98% increase. Straw biochar also improved plant available water in the Planosol by 38% relative to the control, compared with 24% and 21% increases in the vineyard-pruning biochars, produced at 525 °C and 400 °C, respectively. Our study supports the theory that coarse-textured soils have the most to gain structurally from biochar amendments. We also show that straw biochar was the most effective at improving soil aggregate stability and plant available water in a coarse-textured Planosol.

  • Trace element concentrations in leachates and mustard plant tissue (Sinapis alba L.) after biochar application to temperate soils
    Science of The Total Environment, 2014
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Barbara Kitzler, Eva Oburger, Walter W. Wenzel, Gerhard Soja
    Abstract:

    Abstract Biochar application to agricultural soils has been increasingly promoted worldwide. However, this may be accompanied by unexpected side effects in terms of trace element (TE) behavior. We used a greenhouse pot experiment to study the influence of woodchip-derived biochar (wcBC) on leaching and plant concentration of various TEs (Al, Cd, Cu, Pb, Mn, As, B, Mo, Se). Three different agricultural soils from Austria (Planosol, Cambisol, Chernozem) were treated with wcBC at application rates of 1 and 3% (w/w) and subsequently planted with mustard (Sinapis alba L.). Soil samples were taken 0 and 7 months after the start of the pot experiment, and leachate water was collected twice (days 0 and 54). The extractability (with NH4NO3) of cationic TEs was decreased in the (acidic) Planosol and Cambisol after wcBC application, whereas in the (neutral) Chernozem it hardly changed. In contrast, anionic TEs were mobilized in all three soils, which resulted in higher anion concentrations in the leachates. The application of wcBC had no effect on Al and Pb in the mustard plants, but increased their B and Mo concentrations and decreased their Cd, Cu and Mn concentrations. A two-way analysis of variance showed significant interactions between wcBC application rate and soil type for most TEs, which indicates that different soil types may react differently upon wcBC application. Correlation and partial correlation analyses revealed that TE behavior was primarily related to soil pH, whereas the involvement of other factors such as electrical conductivity (EC), organic carbon (OC) content and dissolved organic carbon (DOC) was found to be more soil and TE-specific. The application of wcBC may be a useful strategy for the remediation of soils with elevated levels of cationic TEs, but could lead to deficiencies of cationic micronutrients and enhance short-term translocation of anionic TEs towards the groundwater at high leaching rates.

  • Biochar application to temperate soils: Effects on soil fertility and crop growth under greenhouse conditions
    Journal of Plant Nutrition and Soil Science, 2014
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Franziska Rempt, Gerhard Soja
    Abstract:

    Biochar (BC) application as a soil amendment has aroused much interest and was found to considerably improve soil nutrient status and crop yields on poor, tropical soils. However, information on the effect of BC on temperate soils is still insufficient, with effects expected to differ from tropical soils. We investigated the effects of BC on soil nutrient dynamics, crop yield, and quality in a greenhouse pot experiment. We compared three agricultural soils (Planosol, Cambisol, Chernozem), and BCs of three different feedstocks (wheat straw [WS], mixed woodchips [WC], vineyard pruning [VP]) slowly pyrolyzed at 525°C, of which the latter was also pyrolyzed at 400°C. The BCs were applied at two rates (1% and 3%, which would correspond to 30 and 90 t ha-1 in the field). Three crops, namely mustard (Sinapis alba L.), barley (Hordeum vulgare L.), and red clover (Trifolium pretense L.) were grown successively within one year. The investigated soil properties included pH, electrical conductivity (EC), cation-exchange capacity (CEC), calcium-acetate-lactate (CAL)-extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show a pH increase in all soils. The CEC increased only on the Planosol. The C : N ratio increased at 3% application rate. Despite improving the soil nutrient status partly, yields of the first crop (mustard) and to a lesser extent of the second crop (barley) were significantly depressed through BC application (by up to 68%); the yield of clover as third crop was not affected. Only the BC from WS maintained yields in the range of the control and even increased barley yield by 6%. The initial yield reduction was accompanied by notable decreases (Cu, Fe, Mn, Zn) and increases (Mo) in micronutrient concentrations of plant tissues while nitrogen concentrations were hardly affected. The results of the pot experiment show that despite additional mineral fertilization, short-term growth inhibition may occur when applying BC without further treatment to temperate soils. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Biochar application to temperate soils: Effects on soil fertility and crop growth under greenhouse conditions
    Journal of Plant Nutrition and Soil Science, 2013
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Franziska Rempt, Gerhard Soja
    Abstract:

    Biochar (BC) application as a soil amendment has aroused much interest and was found to considerably improve soil nutrient status and crop yields on poor, tropical soils. However, information on the effect of BC on temperate soils is still insufficient, with effects expected to differ from tropical soils. We investigated the effects of BC on soil nutrient dynamics, crop yield, and quality in a greenhouse pot experiment. We compared three agricultural soils (Planosol, Cambisol, Chernozem), and BCs of three different feedstocks (wheat straw [WS], mixed woodchips [WC], vineyard pruning [VP]) slowly pyrolyzed at 525°C, of which the latter was also pyrolyzed at 400°C. The BCs were applied at two rates (1% and 3%, which would correspond to 30 and 90 t ha–1 in the field). Three crops, namely mustard (Sinapis alba L.), barley (Hordeum vulgare L.), and red clover (Trifolium pretense L.) were grown successively within one year. The investigated soil properties included pH, electrical conductivity (EC), cation-exchange capacity (CEC), calcium-acetate-lactate (CAL)–extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show a pH increase in all soils. The CEC increased only on the Planosol. The C : N ratio increased at 3% application rate. Despite improving the soil nutrient status partly, yields of the first crop (mustard) and to a lesser extent of the second crop (barley) were significantly depressed through BC application (by up to 68%); the yield of clover as third crop was not affected. Only the BC from WS maintained yields in the range of the control and even increased barley yield by 6%. The initial yield reduction was accompanied by notable decreases (Cu, Fe, Mn, Zn) and increases (Mo) in micronutrient concentrations of plant tissues while nitrogen concentrations were hardly affected. The results of the pot experiment show that despite additional mineral fertilization, short-term growth inhibition may occur when applying BC without further treatment to temperate soils.

Franz Zehetner - One of the best experts on this subject based on the ideXlab platform.

  • Changes in biochar physical and chemical properties: Accelerated biochar aging in an acidic soil
    Carbon, 2017
    Co-Authors: Maria V. Rechberger, Stefanie Kloss, Gerhard Soja, Harald Rennhofer, Johannes Tintner, Andrea Watzinger, Helga C. Lichtenegger, Franz Zehetner
    Abstract:

    Biochar (BC) is increasingly used as soil amendment; however, its stability and alteration in the soil environment are still unclear. Here, we investigated BC decomposition and changes of BC characteristics during a long-term incubation experiment. 13C-depleted BCs were incubated for two years in an acidic Planosol and a calcareous Chernozem, respectively. BC decomposition inferred from the C isotope signature of the incubated materials was marginal. Yet, small angle X-ray scattering showed that the surface roughness of the BCs increased over time. Mid-infrared spectra indicated changes in the BCs' molecular characteristics upon aging. There was an overall increase of infrared bands assigned to H- and O-containing functional groups, especially carboxylic groups. Contact angle measurements revealed that the hydrophobic surfaces of freshly produced BCs became more hydrophilic during soil incubation. Our results suggest that BC aging is strongly influenced by soil traits. In the more acidic Planosol, these aging processes were accelerated.

  • Long-term effects of biochar on soil physical properties
    Geoderma, 2016
    Co-Authors: Leigh D. Burrell, Nicola Rampazzo, Franz Zehetner, Bernhard Wimmer, Gerhard Soja
    Abstract:

    A growing body of research into the effects of biochar on soil physical characteristics suggests that it is most effective in coarse-textured soils. In this study, we set out to test this theory by comparing the effects of a woodchip biochar on a Chernozem, Cambisol and a coarse-textured Planosol in a pot experiment. We also compared the effect of different biochars on the Planosol, including woodchip biochar, straw biochar, and two vineyard-pruning biochars produced at different pyrolysis temperatures. Three characteristics were measured as indicators of good soil structure: bulk density, soil aggregate stability and plant available water. The woodchip biochar induced greater decreases in bulk density in the coarse textured Planosol than in the other soils. It also had a greater effect on soil aggregate stability in the Planosol than in the Cambisol, but had no effect on the Chernozem. Woodchip biochar had no effect on plant available water in any of the three soils. Straw biochar was the most effective at improving soil aggregate stability in the coarse-textured Planosol, with a 98% increase. Straw biochar also improved plant available water in the Planosol by 38% relative to the control, compared with 24% and 21% increases in the vineyard-pruning biochars, produced at 525 °C and 400 °C, respectively. Our study supports the theory that coarse-textured soils have the most to gain structurally from biochar amendments. We also show that straw biochar was the most effective at improving soil aggregate stability and plant available water in a coarse-textured Planosol.

  • Trace element concentrations in leachates and mustard plant tissue (Sinapis alba L.) after biochar application to temperate soils
    Science of The Total Environment, 2014
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Barbara Kitzler, Eva Oburger, Walter W. Wenzel, Gerhard Soja
    Abstract:

    Abstract Biochar application to agricultural soils has been increasingly promoted worldwide. However, this may be accompanied by unexpected side effects in terms of trace element (TE) behavior. We used a greenhouse pot experiment to study the influence of woodchip-derived biochar (wcBC) on leaching and plant concentration of various TEs (Al, Cd, Cu, Pb, Mn, As, B, Mo, Se). Three different agricultural soils from Austria (Planosol, Cambisol, Chernozem) were treated with wcBC at application rates of 1 and 3% (w/w) and subsequently planted with mustard (Sinapis alba L.). Soil samples were taken 0 and 7 months after the start of the pot experiment, and leachate water was collected twice (days 0 and 54). The extractability (with NH4NO3) of cationic TEs was decreased in the (acidic) Planosol and Cambisol after wcBC application, whereas in the (neutral) Chernozem it hardly changed. In contrast, anionic TEs were mobilized in all three soils, which resulted in higher anion concentrations in the leachates. The application of wcBC had no effect on Al and Pb in the mustard plants, but increased their B and Mo concentrations and decreased their Cd, Cu and Mn concentrations. A two-way analysis of variance showed significant interactions between wcBC application rate and soil type for most TEs, which indicates that different soil types may react differently upon wcBC application. Correlation and partial correlation analyses revealed that TE behavior was primarily related to soil pH, whereas the involvement of other factors such as electrical conductivity (EC), organic carbon (OC) content and dissolved organic carbon (DOC) was found to be more soil and TE-specific. The application of wcBC may be a useful strategy for the remediation of soils with elevated levels of cationic TEs, but could lead to deficiencies of cationic micronutrients and enhance short-term translocation of anionic TEs towards the groundwater at high leaching rates.

  • Biochar application to temperate soils: Effects on soil fertility and crop growth under greenhouse conditions
    Journal of Plant Nutrition and Soil Science, 2014
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Franziska Rempt, Gerhard Soja
    Abstract:

    Biochar (BC) application as a soil amendment has aroused much interest and was found to considerably improve soil nutrient status and crop yields on poor, tropical soils. However, information on the effect of BC on temperate soils is still insufficient, with effects expected to differ from tropical soils. We investigated the effects of BC on soil nutrient dynamics, crop yield, and quality in a greenhouse pot experiment. We compared three agricultural soils (Planosol, Cambisol, Chernozem), and BCs of three different feedstocks (wheat straw [WS], mixed woodchips [WC], vineyard pruning [VP]) slowly pyrolyzed at 525°C, of which the latter was also pyrolyzed at 400°C. The BCs were applied at two rates (1% and 3%, which would correspond to 30 and 90 t ha-1 in the field). Three crops, namely mustard (Sinapis alba L.), barley (Hordeum vulgare L.), and red clover (Trifolium pretense L.) were grown successively within one year. The investigated soil properties included pH, electrical conductivity (EC), cation-exchange capacity (CEC), calcium-acetate-lactate (CAL)-extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show a pH increase in all soils. The CEC increased only on the Planosol. The C : N ratio increased at 3% application rate. Despite improving the soil nutrient status partly, yields of the first crop (mustard) and to a lesser extent of the second crop (barley) were significantly depressed through BC application (by up to 68%); the yield of clover as third crop was not affected. Only the BC from WS maintained yields in the range of the control and even increased barley yield by 6%. The initial yield reduction was accompanied by notable decreases (Cu, Fe, Mn, Zn) and increases (Mo) in micronutrient concentrations of plant tissues while nitrogen concentrations were hardly affected. The results of the pot experiment show that despite additional mineral fertilization, short-term growth inhibition may occur when applying BC without further treatment to temperate soils. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Biochar application to temperate soils: Effects on soil fertility and crop growth under greenhouse conditions
    Journal of Plant Nutrition and Soil Science, 2013
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Franziska Rempt, Gerhard Soja
    Abstract:

    Biochar (BC) application as a soil amendment has aroused much interest and was found to considerably improve soil nutrient status and crop yields on poor, tropical soils. However, information on the effect of BC on temperate soils is still insufficient, with effects expected to differ from tropical soils. We investigated the effects of BC on soil nutrient dynamics, crop yield, and quality in a greenhouse pot experiment. We compared three agricultural soils (Planosol, Cambisol, Chernozem), and BCs of three different feedstocks (wheat straw [WS], mixed woodchips [WC], vineyard pruning [VP]) slowly pyrolyzed at 525°C, of which the latter was also pyrolyzed at 400°C. The BCs were applied at two rates (1% and 3%, which would correspond to 30 and 90 t ha–1 in the field). Three crops, namely mustard (Sinapis alba L.), barley (Hordeum vulgare L.), and red clover (Trifolium pretense L.) were grown successively within one year. The investigated soil properties included pH, electrical conductivity (EC), cation-exchange capacity (CEC), calcium-acetate-lactate (CAL)–extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show a pH increase in all soils. The CEC increased only on the Planosol. The C : N ratio increased at 3% application rate. Despite improving the soil nutrient status partly, yields of the first crop (mustard) and to a lesser extent of the second crop (barley) were significantly depressed through BC application (by up to 68%); the yield of clover as third crop was not affected. Only the BC from WS maintained yields in the range of the control and even increased barley yield by 6%. The initial yield reduction was accompanied by notable decreases (Cu, Fe, Mn, Zn) and increases (Mo) in micronutrient concentrations of plant tissues while nitrogen concentrations were hardly affected. The results of the pot experiment show that despite additional mineral fertilization, short-term growth inhibition may occur when applying BC without further treatment to temperate soils.

Bernhard Wimmer - One of the best experts on this subject based on the ideXlab platform.

  • Long-term effects of biochar on soil physical properties
    Geoderma, 2016
    Co-Authors: Leigh D. Burrell, Nicola Rampazzo, Franz Zehetner, Bernhard Wimmer, Gerhard Soja
    Abstract:

    A growing body of research into the effects of biochar on soil physical characteristics suggests that it is most effective in coarse-textured soils. In this study, we set out to test this theory by comparing the effects of a woodchip biochar on a Chernozem, Cambisol and a coarse-textured Planosol in a pot experiment. We also compared the effect of different biochars on the Planosol, including woodchip biochar, straw biochar, and two vineyard-pruning biochars produced at different pyrolysis temperatures. Three characteristics were measured as indicators of good soil structure: bulk density, soil aggregate stability and plant available water. The woodchip biochar induced greater decreases in bulk density in the coarse textured Planosol than in the other soils. It also had a greater effect on soil aggregate stability in the Planosol than in the Cambisol, but had no effect on the Chernozem. Woodchip biochar had no effect on plant available water in any of the three soils. Straw biochar was the most effective at improving soil aggregate stability in the coarse-textured Planosol, with a 98% increase. Straw biochar also improved plant available water in the Planosol by 38% relative to the control, compared with 24% and 21% increases in the vineyard-pruning biochars, produced at 525 °C and 400 °C, respectively. Our study supports the theory that coarse-textured soils have the most to gain structurally from biochar amendments. We also show that straw biochar was the most effective at improving soil aggregate stability and plant available water in a coarse-textured Planosol.

  • Trace element concentrations in leachates and mustard plant tissue (Sinapis alba L.) after biochar application to temperate soils
    Science of The Total Environment, 2014
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Barbara Kitzler, Eva Oburger, Walter W. Wenzel, Gerhard Soja
    Abstract:

    Abstract Biochar application to agricultural soils has been increasingly promoted worldwide. However, this may be accompanied by unexpected side effects in terms of trace element (TE) behavior. We used a greenhouse pot experiment to study the influence of woodchip-derived biochar (wcBC) on leaching and plant concentration of various TEs (Al, Cd, Cu, Pb, Mn, As, B, Mo, Se). Three different agricultural soils from Austria (Planosol, Cambisol, Chernozem) were treated with wcBC at application rates of 1 and 3% (w/w) and subsequently planted with mustard (Sinapis alba L.). Soil samples were taken 0 and 7 months after the start of the pot experiment, and leachate water was collected twice (days 0 and 54). The extractability (with NH4NO3) of cationic TEs was decreased in the (acidic) Planosol and Cambisol after wcBC application, whereas in the (neutral) Chernozem it hardly changed. In contrast, anionic TEs were mobilized in all three soils, which resulted in higher anion concentrations in the leachates. The application of wcBC had no effect on Al and Pb in the mustard plants, but increased their B and Mo concentrations and decreased their Cd, Cu and Mn concentrations. A two-way analysis of variance showed significant interactions between wcBC application rate and soil type for most TEs, which indicates that different soil types may react differently upon wcBC application. Correlation and partial correlation analyses revealed that TE behavior was primarily related to soil pH, whereas the involvement of other factors such as electrical conductivity (EC), organic carbon (OC) content and dissolved organic carbon (DOC) was found to be more soil and TE-specific. The application of wcBC may be a useful strategy for the remediation of soils with elevated levels of cationic TEs, but could lead to deficiencies of cationic micronutrients and enhance short-term translocation of anionic TEs towards the groundwater at high leaching rates.

  • Biochar application to temperate soils: Effects on soil fertility and crop growth under greenhouse conditions
    Journal of Plant Nutrition and Soil Science, 2014
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Franziska Rempt, Gerhard Soja
    Abstract:

    Biochar (BC) application as a soil amendment has aroused much interest and was found to considerably improve soil nutrient status and crop yields on poor, tropical soils. However, information on the effect of BC on temperate soils is still insufficient, with effects expected to differ from tropical soils. We investigated the effects of BC on soil nutrient dynamics, crop yield, and quality in a greenhouse pot experiment. We compared three agricultural soils (Planosol, Cambisol, Chernozem), and BCs of three different feedstocks (wheat straw [WS], mixed woodchips [WC], vineyard pruning [VP]) slowly pyrolyzed at 525°C, of which the latter was also pyrolyzed at 400°C. The BCs were applied at two rates (1% and 3%, which would correspond to 30 and 90 t ha-1 in the field). Three crops, namely mustard (Sinapis alba L.), barley (Hordeum vulgare L.), and red clover (Trifolium pretense L.) were grown successively within one year. The investigated soil properties included pH, electrical conductivity (EC), cation-exchange capacity (CEC), calcium-acetate-lactate (CAL)-extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show a pH increase in all soils. The CEC increased only on the Planosol. The C : N ratio increased at 3% application rate. Despite improving the soil nutrient status partly, yields of the first crop (mustard) and to a lesser extent of the second crop (barley) were significantly depressed through BC application (by up to 68%); the yield of clover as third crop was not affected. Only the BC from WS maintained yields in the range of the control and even increased barley yield by 6%. The initial yield reduction was accompanied by notable decreases (Cu, Fe, Mn, Zn) and increases (Mo) in micronutrient concentrations of plant tissues while nitrogen concentrations were hardly affected. The results of the pot experiment show that despite additional mineral fertilization, short-term growth inhibition may occur when applying BC without further treatment to temperate soils. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Biochar application to temperate soils: Effects on soil fertility and crop growth under greenhouse conditions
    Journal of Plant Nutrition and Soil Science, 2013
    Co-Authors: Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, Jannis Buecker, Franziska Rempt, Gerhard Soja
    Abstract:

    Biochar (BC) application as a soil amendment has aroused much interest and was found to considerably improve soil nutrient status and crop yields on poor, tropical soils. However, information on the effect of BC on temperate soils is still insufficient, with effects expected to differ from tropical soils. We investigated the effects of BC on soil nutrient dynamics, crop yield, and quality in a greenhouse pot experiment. We compared three agricultural soils (Planosol, Cambisol, Chernozem), and BCs of three different feedstocks (wheat straw [WS], mixed woodchips [WC], vineyard pruning [VP]) slowly pyrolyzed at 525°C, of which the latter was also pyrolyzed at 400°C. The BCs were applied at two rates (1% and 3%, which would correspond to 30 and 90 t ha–1 in the field). Three crops, namely mustard (Sinapis alba L.), barley (Hordeum vulgare L.), and red clover (Trifolium pretense L.) were grown successively within one year. The investigated soil properties included pH, electrical conductivity (EC), cation-exchange capacity (CEC), calcium-acetate-lactate (CAL)–extractable P (PCAL) and K (KCAL), C, N, and nitrogen-supplying potential (NSP). The results show a pH increase in all soils. The CEC increased only on the Planosol. The C : N ratio increased at 3% application rate. Despite improving the soil nutrient status partly, yields of the first crop (mustard) and to a lesser extent of the second crop (barley) were significantly depressed through BC application (by up to 68%); the yield of clover as third crop was not affected. Only the BC from WS maintained yields in the range of the control and even increased barley yield by 6%. The initial yield reduction was accompanied by notable decreases (Cu, Fe, Mn, Zn) and increases (Mo) in micronutrient concentrations of plant tissues while nitrogen concentrations were hardly affected. The results of the pot experiment show that despite additional mineral fertilization, short-term growth inhibition may occur when applying BC without further treatment to temperate soils.

  • Soil microbial communities responded to biochar application in temperate soils and slowly metabolized 13C‐labelled biochar as revealed by 13C PLFA analyses: results from a short‐term incubation and pot experiment
    European Journal of Soil Science, 2013
    Co-Authors: Andrea Watzinger, Stefanie Kloss, Franz Zehetner, Bernhard Wimmer, S. Feichtmair, Barbara Kitzler, Sophie Zechmeister-boltenstern, Gerhard Soja
    Abstract:

    Summary This study investigates (i) the effect of biochar amendments on soil microbial communities in temperate agricultural soils, (ii) the involvement of microorganisms (MOs) in degradation of biochar and (iii) techniques to quantify degradation of biochar in short-term experiments. The study involved an incubation experiment and a pot experiment with two arable soils (a sandy acidic Planosol and a calcareous loamy Chernozem) amended with 13C-depleted biochar from wheat husk and willow plants. Phospholipid fatty acids (PLFAs), 13C-PLFA, CO2, 13C-CO2, soil organic carbon (Corg) and 13C-Corg were monitored for 100 days. Effects of biochar application on the soil microorganisms (MOs) were generally minor. In the incubation experiment, microbial biomass was elevated by wheat husk biochar, especially in the Planosol. The increase in PLFAs was attributed to Gram-negative bacteria and actinomycetes. Fungi and Gram-positive bacteria were less affected. In the pot experiment, MOs did not respond to the addition of willow biochar. The effects of biochar were mainly attributed to an increase in the pH of the Planosol. Additionally, MOs were probably less responsive to inorganic fertilizer in biochar-amended soil. In the incubation, only the actinomycetal PLFA 10Me18:0 incorporated biochar C, while in the pot experiment, Gram-negative bacterial PLFAs (16:1ω7c, 16:1ω5c, 18:1ω7c) and Me16:0 & i17:1ω8 and i17:0 indicated degradation of biochar after 5 weeks. Uptake of around 20% biochar C in these PLFAs was monitored, which accounts for 2% biochar C in the total microbial biomass. From the PLFA data the mean residence time of biochar carbon was estimated in time-scales of centuries to millennia. The CO2 concentration decreased after biochar addition until its production was masked by root respiration. The use of 13C-CO2 labelling to estimate degradation was complicated by the interference with an initial negative priming effect and the dissolution/precipitation of carbonate. In conclusion, soil MOs were not particularly affected by addition of biochar, and the effects recorded were mainly attributed to changing environmental conditions after biochar addition. Nonetheless, uptake of 13C label into microbial PLFAs was successfully used to estimate microbial degradation of biochar in short-term experiments.

K Araya - One of the best experts on this subject based on the ideXlab platform.

  • improvement of Planosol solum part 10 mixing of wheat straw and corn stalk into subsoil
    Journal of Agricultural Engineering Research, 1998
    Co-Authors: H Zhang, C Zhang, K Araya, M Kudoh, H Kawabe
    Abstract:

    Abstract Based on field cultivation tests by Zhao and soil investigations by Araya, a one-to-one mixing of the second (Aw) and third (B) horizons was conducted to improve the Planosol solum in China, leaving the first (Ap) horizon undisturbed by a three-stage subsoil mixing plough. Thispaper deals with the collection of wheat straws and corn stalks which are left on fields after harvesting by combines, how to mix them into the subsoil and the determination of the limiting length of wheat straw and corn stalk to mix into the subsoil. It was postulated that, if organic matter such as the wheat straw or corn stalk is mixed into the subsoil, where the Aw and B horizons are mixed, low soil hardness may be sustainable because of increased pores within the aggregated formation. The results showed that when a curved plate and a finger-wheel rake were combined, the required straw and stalk collection was obtained. The wheat straws or corn stalks on the soil surface were first collected by the finger-wheel rake and then, dropped by the curved plate, into the furrow at the rear of the third plough body. The collection rates of wheat straws and corn stalks decreased when their lengths were less than 200 and 300 mm, respectively. For good mixing with the subsoil, the lengths of both wheat straws and corn stalks should be less than 300 mm. Cutting of the straws and stalks may be necessary to achieve this.

  • improvement of Planosol solum part 9 fertilizer distributor for subsoil
    Journal of Agricultural Engineering Research, 1998
    Co-Authors: C Zhang, H Zhang, K Araya, M Kudoh, H Kawabe
    Abstract:

    Abstract Based on field cultivation tests by Zhao and soil investigations by Araya, a one-to-one mixing of the second (Aw) and third (B) horizons was conducted to improve the Planosol solum in China, leaving the first (Ap) horizon undisturbed by a three-stage subsoil mixing plough. This paper deals with the development of a fertilizer distributor which applies chemical fertilizers into the subsoil, where the Aw and B horizons, which are lacking in phosphorous and calcium, are mixed. Additionally, based on root density distribution of plants, this paper deals with the development of a technique in which the fertilizer is placed more densely in the upper layer than in the lower layer within the 200–600 mm depth of subsoil. The results showed that when both granular and powder fertilizers were supplied at the rear of the first or second plough body, the fertilizers reached the bottom layer with soil mixing by the plough bodies, and the fertilizer distribution density was greatest in the lower layer of the subsoil. When the fertilizers were supplied at the side of the third plough body, an improved distribution was obtained. However, the fertilizer was not distributed over the entire operating width (300 mm), but was concentrated more around the side of the third plough body. As a result, when the fertilizer was supplied both at the rear of the third plough and the side of the third plough body, the distribution sought was obtained. Here, the distribution density of the fertilizer decreased linearly with the tilled soil depth in the subsoil.

  • improvement of Planosol solum part 7 mechanical properties of soils
    Journal of Agricultural Engineering Research, 1998
    Co-Authors: H Zhang, C Zhang, K Araya, M Kudoh, H Kawabe
    Abstract:

    Abstract The Planosol solum in China is a binary mixture of soil particles where silt forms the frame structure and clay fills the pore spaces. It is extremely hard and impermeable and has particular mechanical properties. This paper deals with the mechanical properties of the three horizons (Ap, Aw and B) of the Planosol solum as an aid to understanding the draught requirement of a three-stage subsoil mixing plough for improvement of the Planosol solum. Pseudogley soil which is a typical heavy clay soil in Japan was also tested for comparison. Tensile strength, compressive strength, shearing strength, soil-metal friction as static properties and soil brittleness as a dynamic property were determined. The results show that the cohesive strengths of all soils, except the B horizon, had maximums at particular soil water contents. These values were nearly the same as the plastic limits. The B horizon did not have a maximum value in the range of soil water content studied. The cohesion of the pseudogley soil was the smallest and that of the Aw horizon was the largest. The Ap and Aw horizons had the same trend in brittleness; the impact energy required to fracture both soils increased with decreasing soil water content. The required impact energy of the B horizon showed a quite different trend from that of the other soils and was a maximum at 30% d.b. soil water content. When the B horizon was dry, the required impact energy decreased and it became brittle. The commonly occurring soil water content in the actual Planosol fields was more than 20% d.b. In this range, the tensile strength of the Aw horizon was the largest, followed by the B horizon, Ap horizon and pseudogley soil. Comparing the cohesion at soil water contents in excess of 20% d.b., the tensile strength of the pseudogley soil was about one-seventh of its cohesion but the tensile strengths of all Planosols was about one-half of their cohesive values.

  • improvement of Planosol solum part 8 analysis of draught of a three stage subsoil mixing plough
    Journal of Agricultural Engineering Research, 1998
    Co-Authors: H Zhang, C Zhang, K Araya, M Kudoh, H Kawabe
    Abstract:

    Abstract Based on earlier field cultivation tests and soil investigations, a one-to-one mixing of the second (Aw) and third (B) horizons was conducted to improve the Planosol solum in China, leaving the first (Ap) horizon undistributed by a three-stage subsoil mixing plough. The Ap and Aw horizons have a thickness of about 200 mm. The layer below about 400 mm depth is the B horizon. This paper deals with the mechanism of draught production of the second and third plough bodies of the three-stage subsoil mixing plough. The results showed that in both the model and the field tests with the studied soils, the resistances caused by upheaving, tension and cohesion were the largest contributors to the total draught, and the resistances caused by soil acceleration and adhesion were extremely small. In both the model and the field tests, measured and predicted draughts were in reasonable agreement. In the soil bin tests using a half-scale model plough in Japan where a Japanese pseudogley soil was used and the soil hardness in the soil bin was the same throughout, both predicted and measured combined draughts produced by the second and third plough bodies, where each plough body tilled a 100 mm depth, were smaller than that produced when a 200 mm depth soil was tilled by the third plough body alone, if the second plough body was removed and the three-stage subsoil mixing plough was used as a two-stage subsoil mixing plough. In the full-scale three-stage subsoil mixing plough tests in China, the draughts of the second plough body which tilled the Aw horizon and third plough body which tilled the B horizon, were nearly the same, despite the fact that the size of the third plough body was larger than that of the second plough body, because the cohesive and the tensile strengths of the Aw horizon, the second horizon, were larger than those of the B horizon, the third horizon. Here also, the combined draught produced by the second and third plough bodies, where each plough body tilled a 200 mm depth, was smaller than that produced when a 400 mm depth soil was tilled by the third plough body alone, if the second plough body was removed. If the second plough body was eliminated and the Aw and B horizons of the 400 mm depth were directly tilled by the third plough body alone, the draught requirement was steeply increased and large soil clods were formed by the tillage of the third plough body.

  • improvement of Planosol solum part 6 field experiments with a three stage subsoil mixing plough
    Journal of Agricultural Engineering Research, 1996
    Co-Authors: K Araya, M Kudoh, D Zhao
    Abstract:

    A drop-down type plough (two-stage subsoil mixing plough) was effective for the one-to-one mixing of the second (Aw) and third (B) horizons to improve the Planosol solum in China leaving the first (Ap) horizon undisturbed. However, this machine had the following disadvantages: (1) it produced large soil clods, (2) it had a large draught requirement, (3) it required a furrow following system, (4) it has poor frame strength, and (5) it was necessary to remove the first plough body to facilitate opening of the first furrow. Basic soil bin tests were conducted in Japan to develop a three-stage subsoil mixing plough to solve these problems using half-size model ploughs. The results showed that the draught requirement and clod size, could be reduced by using three plough bodies; one for the Ap, one for the Aw and one for the B horizons. A slatted mouldboard should be used to minimize draught rather than a plate mouldboard. The optimum working widths of the second and third plough bodies were 150 mm, which minimized draught but resulted in a wider working width than the nominal value.

Alemayehu Regassa Tolossa - One of the best experts on this subject based on the ideXlab platform.

  • impact of traditional soil burning guie on Planosol properties and land use intensification in south western ethiopia
    Soil Use and Management, 2015
    Co-Authors: Mathijs Dumon, Alemayehu Regassa Tolossa, K Mertens, Ann Verdoodt, J Deckers, E Van Ranst
    Abstract:

    In the Gilgel Gibe catchment in Ethiopia, local farmers intensify land use on Planosols by adjusting a traditional soil burning practice known as guie. The burning practice used to be applied in a cycle of shifting cultivation. However, more recently, farmers burn small plots to make fertile seedbeds for Eucalyptus seedlings in the first year before these trees are transplanted to larger plots. The purpose of this research was to assess the physico-chemical properties of Planosols that have been subjected to burning over the last 10 yrs and evaluate the contribution of guie to land-use intensification of these soils. Transect studies and interviews of local farmers, followed by chemical, physical and micromorphological analyses of samples from selected plots were used to compare the soil properties of recently (0–2 yrs) and formerly (3–10 yrs) burnt Planosols with those of unburnt Planosols. The analytical results show that the burning practice improved nutrient availability in the first 2 yrs after guie. Increased amounts of exchangeable aluminium (Al) were reported in the long term. Charge fingerprints illustrate that the nutrient-buffering capacity of the soil was high shortly after the practice but subsequently decreased with time. Given the population pressure on the formerly extensively used Planosols, it is argued that the current application of guie on small, localized plots for raising Eucalyptus seedlings is well adapted to the local socio-economic context and promotes land-use intensification on the Planosols. The increased exchangeable Al content of former Eucalyptus seedbeds merits further in-depth research into the biophysical sustainability of the burning practice.

  • quantitative clay mineralogy of a vertic Planosol in southwestern ethiopia impact on soil formation hypotheses
    Geoderma, 2014
    Co-Authors: Mathijs Dumon, Alemayehu Regassa Tolossa, Boris Capon, Christophe Detavernier, Eric Van Ranst
    Abstract:

    Abstract Planosols, characterised by a bleached, silt-textured surface horizon abruptly overlying a dense, clayey subsoil, are a very common soil type in Ethiopia. The origin of the abrupt textural change is still often debated in literature. One of the processes frequently put forward to explain the coarse textured material in the topsoil is ‘ferrolysis’: an oxidation–reduction sequence driven by bacterial decomposition of soil organic matter, resulting in the destruction of open 2:1 clay minerals. Recent studies of representative profiles of Vertic Planosols in south-western Ethiopia indicate that these soils are composed of a weathered volcanic ash layer deposited on top of a deflated vertic subsoil, which refutes the ferrolysis hypothesis. To strengthen the geogenetic origin of these profiles, a quantitative mineralogical analysis of the clay fraction was undertaken. Results of a sequential fractionation revealed a strong aggregation of clay particles in the bleached horizon, while the effect of aggregation was far more limited in the vertic horizon. This is believed to be related to the dispersed, impregnative nature of iron oxides in the bleached horizon, compared to the segregated nature of the sharp, nodular concretions found in the vertic horizon. The annealing XRD analysis revealed only minor changes in dehydroxylation temperatures of kaolinites and 2:1 minerals between untreated and DCB-treated samples, indicating that the pretreatment did not significantly alter the mineral lattices. Multi-specimen, full-profile fitting of XRD patterns revealed no large quantitative differences between sub-fractions of the bleached and vertic horizons, although a net increase of 1:1 layers over 2:1 layers towards the top of the profile can be observed in the bleached horizon. This could be interpreted as the result of neo-formation of kaolinite. The main mineralogical differences between the bleached and vertic horizons of the

  • Quality assessment for brick making of the bleached topsoil of Vertic Planosols in the south-western Ethiopian Highlands
    The EGU General Assembly, 2013
    Co-Authors: Mathijs Dumon, Alemayehu Regassa Tolossa, Laure Vandemeulebroeke, Kim Van Daele, Vicky Proost, Eric Van Ranst
    Abstract:

    Planosols are a very common soil type in Ethiopia. The Vertic Planosols of the south-western Highlands are typical examples of duplex soils, characterized by a bleached, silty top horizon abruptly overlying a heavy clay subsoil. The bleached topsoil material is of local economic importance as it is extensively used for brick making. The aim of this research was to assess the quality of locally produced bricks following Ethiopian and European quality standards, and formulating recommendations to improve the quality of the bricks.

  • Revisiting ferrolysis processes in the formation of Planosols for rationalizing the soils with stagnic properties in WRB
    Geoderma, 2011
    Co-Authors: Eric Van Ranst, Mathijs Dumon, Alemayehu Regassa Tolossa, Jean-thomas Cornélis, Georges Stoops, Robert Vandenberghe, Seppe Deckers
    Abstract:

    Abstract Planosols have been recognized as a Major Soil Group right from the beginning in the legend of the FAO/Unesco Soil Map of the World. Also in WRB system it maintained that position at Reference Soil Group level on the account that a major pedogenetic process, ferrolysis, is underlaying the severe stagnic properties that characterize this group. With the introduction of Stagnosols in WRB in 2006, it appears that a serious overlap has been introduced at Reference Soil Group level. This paper aims to throw new light on the genesis of Planosols, drawing from new soil surveys conducted in the south-western Ethiopian highlands. Representative soil profiles were sampled and analyzed for their physico-chemical, mineralogical and micromorphological properties, and a hypothesis has been forwarded to explain the formation of these Planosols. The conclusion is that it is highly unlikely that ‘ferrolysis’ can be called upon to explain the genesis of Planosols in the Ethiopian highlands, and an alternative geogene hypothesis is put forward to explain the formation of these duplex soils. As Ethiopia is one of the mainstays of Planosols, it is suggested that WRB rethinks its strategy on soils with stagnic properties as there is room for rationalization in view of a generally felt overlap between Planosols and Stagnosols. WRB could rationalize by sub-dueing either the Planosols or the Stagnosols to a lower level.