The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform

Adel Shirmohammadi - One of the best experts on this subject based on the ideXlab platform.

  • mode of transport of surface applied Phosphorus 33 through a clay and sandy soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

  • Mode of Transport of Surface‐Applied Phosphorus‐33 through a Clay and Sandy Soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

Faruk Djodjic - One of the best experts on this subject based on the ideXlab platform.

  • mode of transport of surface applied Phosphorus 33 through a clay and sandy soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

  • Mode of Transport of Surface‐Applied Phosphorus‐33 through a Clay and Sandy Soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

Barbro Ulen - One of the best experts on this subject based on the ideXlab platform.

  • mode of transport of surface applied Phosphorus 33 through a clay and sandy soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

  • Mode of Transport of Surface‐Applied Phosphorus‐33 through a Clay and Sandy Soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

Lars Bergstrom - One of the best experts on this subject based on the ideXlab platform.

  • mode of transport of surface applied Phosphorus 33 through a clay and sandy soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

  • Mode of Transport of Surface‐Applied Phosphorus‐33 through a Clay and Sandy Soil
    Journal of Environmental Quality, 1999
    Co-Authors: Faruk Djodjic, Lars Bergstrom, Barbro Ulen, Adel Shirmohammadi
    Abstract:

    Phosphorus (P) is the limiting nutrient for primary production in most freshwater ecosystems. The magnitude of P leaching from agricultural soils is therefore critical. Preferential flow has been proposed as a major cause for high P losses in structured clay soils. Undisturbed soil of two texturally different soils, that is, a clay soil in which preferential flow was expected to be the main mode of water transport and a sandy soil where piston flow is the dominant process, were used in this study. Use of labeled P made it possible to determine the origin of leached P. An equivalent of 100 kg P ha -1 , labeled with 33 P, was added to the soil surface of each lysimeter. Water equivalents to 100 mm were added on five occasions with 7 d between each watering event. Ponded flow conditions were established during periods when water was added, to trigger preferential flow behavior. Phosphorus leaching loads from clay columns were much higher than P loads from sand columns. The average P leaching load for the five clay columns was 4.0 kg ha -1 , compared to only 56 g ha -1 for the three sand columns. The main part of leached P was in dissolved (PO 4 -P) form. The recently added P prevailed in leachate from the clay soil indicating rapid transport of added P from the soil surface through the profile via macropores.

María Teresa Pérez - One of the best experts on this subject based on the ideXlab platform.

  • Phosphate and ATP uptake by lake bacteria: Does taxonomical identity matter?
    Environmental microbiology, 2016
    Co-Authors: Carina Rofner, Ruben Sommaruga, María Teresa Pérez
    Abstract:

    Phosphorus often limits bacterial production in freshwater ecosystems. However, little is known on whether different bacteria contribute to inorganic and organic Phosphorus uptake proportionally to their relative abundance and production. Here, we followed the temporal dynamics of the main heterotrophic bacterial taxa taking up inorganic phosphate (33 P-Pi) and organic Phosphorus (33 P-ATP) in two mountain lakes and compared them to their contribution to bacterial production (3 H-leucine uptake). The short turnover times for Pi and ATP suggested that in both lakes, Phosphorus was limiting most of the year. The bulk uptake rates and the fractions of cells labelled positive for Pi and ATP uptake followed a seasonal trend with minima in winter and maxima in summer. Generally, the bacterial taxa examined contributed to Pi and ATP uptake proportionally to their relative abundance, but not always to their contribution to bacterial production. For instance, AcI Actinobacteria were often underrepresented in Phosphorus uptake compared with leucine incorporation suggesting they might have high intracellular C:P ratios. Our results emphasize that ATP utilization is widespread among freshwater bacteria and indicate that members within the dominant bacterial taxa (Actinobacteria and Betaproteobacteria) have variable Phosphorus requirements, probably due to their different growth potential and variable degrees of homeostasis.