The Experts below are selected from a list of 5577 Experts worldwide ranked by ideXlab platform

Weixin Cheng - One of the best experts on this subject based on the ideXlab platform.

  • rhizosphere priming effects on soil carbon and nitrogen dynamics among tree species with and without intraspecific competition
    New Phytologist, 2018
    Co-Authors: Feike A Dijkstra, Weixin Cheng, Peng Wang
    Abstract:

    : Rhizosphere priming effects (RPEs) play a central role in modifying soil organic matter mineralization. However, effects of tree species and intraspecific competition on RPEs are poorly understood. We investigated RPEs of three tree species (larch, ash and Chinese fir) and the impact of intraspecific competition of these species on the RPE by growing them at two Planting densities for 140 d. We determined the RPE on soil organic carbon (C) decomposition, gross and net nitrogen (N) mineralization and net Plant N acquisition. Differences in the RPE among species were associated with differences in Plant biomass. Gross N mineralization and net Plant N acquisition increased, but net N mineralization decreased, as the RPE on soil organic C decomposition increased. Intraspecific competition reduced the RPE on soil organic C decomposition, gross and net N mineralization, and net Plant N acquisition, especially for ash and Chinese fir. Microbial N mining may explain the overall positive RPEs across species, whereas Intensified Plant-microbe competition for N may have reduced the RPE with intraspecific competition. Overall, the species-specific effects of tree species play an important role in modulating the magnitude and mechanisms of RPEs and the intraspecific competition on soil C and N dynamics.

  • rhizosphere priming effects on soil carbon and nitrogen dynamics among tree species with and without intraspecific competition
    New Phytologist, 2018
    Co-Authors: Feike A Dijkstra, Weixin Cheng, Peng Wang
    Abstract:

    : Rhizosphere priming effects (RPEs) play a central role in modifying soil organic matter mineralization. However, effects of tree species and intraspecific competition on RPEs are poorly understood. We investigated RPEs of three tree species (larch, ash and Chinese fir) and the impact of intraspecific competition of these species on the RPE by growing them at two Planting densities for 140 d. We determined the RPE on soil organic carbon (C) decomposition, gross and net nitrogen (N) mineralization and net Plant N acquisition. Differences in the RPE among species were associated with differences in Plant biomass. Gross N mineralization and net Plant N acquisition increased, but net N mineralization decreased, as the RPE on soil organic C decomposition increased. Intraspecific competition reduced the RPE on soil organic C decomposition, gross and net N mineralization, and net Plant N acquisition, especially for ash and Chinese fir. Microbial N mining may explain the overall positive RPEs across species, whereas Intensified Plant-microbe competition for N may have reduced the RPE with intraspecific competition. Overall, the species-specific effects of tree species play an important role in modulating the magnitude and mechanisms of RPEs and the intraspecific competition on soil C and N dynamics.

Feike A Dijkstra - One of the best experts on this subject based on the ideXlab platform.

  • rhizosphere priming effects on soil carbon and nitrogen dynamics among tree species with and without intraspecific competition
    New Phytologist, 2018
    Co-Authors: Feike A Dijkstra, Weixin Cheng, Peng Wang
    Abstract:

    : Rhizosphere priming effects (RPEs) play a central role in modifying soil organic matter mineralization. However, effects of tree species and intraspecific competition on RPEs are poorly understood. We investigated RPEs of three tree species (larch, ash and Chinese fir) and the impact of intraspecific competition of these species on the RPE by growing them at two Planting densities for 140 d. We determined the RPE on soil organic carbon (C) decomposition, gross and net nitrogen (N) mineralization and net Plant N acquisition. Differences in the RPE among species were associated with differences in Plant biomass. Gross N mineralization and net Plant N acquisition increased, but net N mineralization decreased, as the RPE on soil organic C decomposition increased. Intraspecific competition reduced the RPE on soil organic C decomposition, gross and net N mineralization, and net Plant N acquisition, especially for ash and Chinese fir. Microbial N mining may explain the overall positive RPEs across species, whereas Intensified Plant-microbe competition for N may have reduced the RPE with intraspecific competition. Overall, the species-specific effects of tree species play an important role in modulating the magnitude and mechanisms of RPEs and the intraspecific competition on soil C and N dynamics.

  • rhizosphere priming effects on soil carbon and nitrogen dynamics among tree species with and without intraspecific competition
    New Phytologist, 2018
    Co-Authors: Feike A Dijkstra, Weixin Cheng, Peng Wang
    Abstract:

    : Rhizosphere priming effects (RPEs) play a central role in modifying soil organic matter mineralization. However, effects of tree species and intraspecific competition on RPEs are poorly understood. We investigated RPEs of three tree species (larch, ash and Chinese fir) and the impact of intraspecific competition of these species on the RPE by growing them at two Planting densities for 140 d. We determined the RPE on soil organic carbon (C) decomposition, gross and net nitrogen (N) mineralization and net Plant N acquisition. Differences in the RPE among species were associated with differences in Plant biomass. Gross N mineralization and net Plant N acquisition increased, but net N mineralization decreased, as the RPE on soil organic C decomposition increased. Intraspecific competition reduced the RPE on soil organic C decomposition, gross and net N mineralization, and net Plant N acquisition, especially for ash and Chinese fir. Microbial N mining may explain the overall positive RPEs across species, whereas Intensified Plant-microbe competition for N may have reduced the RPE with intraspecific competition. Overall, the species-specific effects of tree species play an important role in modulating the magnitude and mechanisms of RPEs and the intraspecific competition on soil C and N dynamics.

Peng Wang - One of the best experts on this subject based on the ideXlab platform.

  • rhizosphere priming effects on soil carbon and nitrogen dynamics among tree species with and without intraspecific competition
    New Phytologist, 2018
    Co-Authors: Feike A Dijkstra, Weixin Cheng, Peng Wang
    Abstract:

    : Rhizosphere priming effects (RPEs) play a central role in modifying soil organic matter mineralization. However, effects of tree species and intraspecific competition on RPEs are poorly understood. We investigated RPEs of three tree species (larch, ash and Chinese fir) and the impact of intraspecific competition of these species on the RPE by growing them at two Planting densities for 140 d. We determined the RPE on soil organic carbon (C) decomposition, gross and net nitrogen (N) mineralization and net Plant N acquisition. Differences in the RPE among species were associated with differences in Plant biomass. Gross N mineralization and net Plant N acquisition increased, but net N mineralization decreased, as the RPE on soil organic C decomposition increased. Intraspecific competition reduced the RPE on soil organic C decomposition, gross and net N mineralization, and net Plant N acquisition, especially for ash and Chinese fir. Microbial N mining may explain the overall positive RPEs across species, whereas Intensified Plant-microbe competition for N may have reduced the RPE with intraspecific competition. Overall, the species-specific effects of tree species play an important role in modulating the magnitude and mechanisms of RPEs and the intraspecific competition on soil C and N dynamics.

  • rhizosphere priming effects on soil carbon and nitrogen dynamics among tree species with and without intraspecific competition
    New Phytologist, 2018
    Co-Authors: Feike A Dijkstra, Weixin Cheng, Peng Wang
    Abstract:

    : Rhizosphere priming effects (RPEs) play a central role in modifying soil organic matter mineralization. However, effects of tree species and intraspecific competition on RPEs are poorly understood. We investigated RPEs of three tree species (larch, ash and Chinese fir) and the impact of intraspecific competition of these species on the RPE by growing them at two Planting densities for 140 d. We determined the RPE on soil organic carbon (C) decomposition, gross and net nitrogen (N) mineralization and net Plant N acquisition. Differences in the RPE among species were associated with differences in Plant biomass. Gross N mineralization and net Plant N acquisition increased, but net N mineralization decreased, as the RPE on soil organic C decomposition increased. Intraspecific competition reduced the RPE on soil organic C decomposition, gross and net N mineralization, and net Plant N acquisition, especially for ash and Chinese fir. Microbial N mining may explain the overall positive RPEs across species, whereas Intensified Plant-microbe competition for N may have reduced the RPE with intraspecific competition. Overall, the species-specific effects of tree species play an important role in modulating the magnitude and mechanisms of RPEs and the intraspecific competition on soil C and N dynamics.

Tao Wang - One of the best experts on this subject based on the ideXlab platform.

  • Intensified Plant n and c pool with more available nitrogen under experimental warming in an alpine meadow ecosystem
    Ecology and Evolution, 2016
    Co-Authors: Fei Peng, Xian Xue, Quangang You, Xiang Chen, Jian Guo, Tao Wang
    Abstract:

    Nitrogen (N) availability is projected to increase in a warming climate. But whether the more available N is immobilized by microbes (thus stimulates soil carbon (C) decomposition), or is absorbed by Plants (thus intensifies C uptake) remains unknown in the alpine meadow ecosystem. Infrared heaters were used to simulate climate warming with a paired experimental design. Soil ammonification, nitrification, and net mineralization were obtained by in situ incubation in a permafrost region of the Qinghai-Tibet Plateau (QTP). Available N significantly increased due to the stimulation of net nitrification and mineralization in 0-30 cm soil layer. Microbes immobilized N in the end of growing season in both warming and control plots. The magnitude of immobilized N was lower in the warming plots. The root N concentration significantly reduced, but root N pool Intensified due to the significant increase in root biomass in the warming treatment. Our results suggest that a warming-induced increase in biomass is the major N sink and will continue to stimulate Plant growth until Plant N saturation, which could sustain the positive warming effect on ecosystem productivity.

Vicevic Marija - One of the best experts on this subject based on the ideXlab platform.

  • Catalytic rearrangement of alpha pinene oxide using spinning disc reactor technology
    2004
    Co-Authors: Vicevic Marija
    Abstract:

    PhD ThesisThis investigation explores the use of environmentally friendly solid acid catalysts based on immobilised Lewis acids in liquid phase organic reaction using the spinning disc reactor. The reaction studied was the rearrangement of a-pinene oxide to campholenic aldehyde, which is an important intermediate used by the fragrance industry in the synthesis of santalol (sandalwood). By focusing on liquid phase reactions and by addressing the particular problems associated with catalysis for such reaction systems the aim of this work is to develop new catalytic technology of value to the highly successful UK fine and speciality chemical industries, where acid catalysis is widely used but normally involves the use of corrosive and toxic reagents, unselective processes and the production of unacceptable levels of hazardous waste. The performance of a compact catalytic spinning disc reactor (SDR) with good heat and mass transfer characteristics for continuous conversion of a-pinene oxide to campholenic aldehyde using supported Zn(OTf)2 catalysts was studied. The spinning disc runs were performed at various conditions and conversion and selectivity were monitored. A 100% conversion of a-pinene oxide was easily achieved for most of the conditions. Lower residence time enhanced selectivity towards aldehyde up to a maximum of 82%, at 60% conversion. SDR empirical models were developed and activation energies determined for each catalyst used. Comparison of SDR with batch process is also made. Results suggest that the catalytic SDR can significantly enhance the reaction rates, reaction selectivity and improve process safety whilst eliminating the loss of catalyst. The findings of this investigation indicate that the vision of realising a truly Intensified Plant using green chemistry to achieve greener technology is a real possibility

  • Catalytic rearrangement of alpha pinene oxide using spinning disc reactor technology
    2004
    Co-Authors: Vicevic Marija
    Abstract:

    This investigation explores the use of environmentally friendly solid acid catalysts based on immobilised Lewis acids in liquid phase organic reaction using the spinning disc reactor. The reaction studied was the rearrangement of a-pinene oxide to campholenic aldehyde, which is an important intermediate used by the fragrance industry in the synthesis of santalol (sandalwood). By focusing on liquid phase reactions and by addressing the particular problems associated with catalysis for such reaction systems the aim of this work is to develop new catalytic technology of value to the highly successful UK fine and speciality chemical industries, where acid catalysis is widely used but normally involves the use of corrosive and toxic reagents, unselective processes and the production of unacceptable levels of hazardous waste. The performance of a compact catalytic spinning disc reactor (SDR) with good heat and mass transfer characteristics for continuous conversion of a-pinene oxide to campholenic aldehyde using supported Zn(OTf)2 catalysts was studied. The spinning disc runs were performed at various conditions and conversion and selectivity were monitored. A 100% conversion of a-pinene oxide was easily achieved for most of the conditions. Lower residence time enhanced selectivity towards aldehyde up to a maximum of 82%, at 60% conversion. SDR empirical models were developed and activation energies determined for each catalyst used. Comparison of SDR with batch process is also made. Results suggest that the catalytic SDR can significantly enhance the reaction rates, reaction selectivity and improve process safety whilst eliminating the loss of catalyst. The findings of this investigation indicate that the vision of realising a truly Intensified Plant using green chemistry to achieve greener technology is a real possibility.EThOS - Electronic Theses Online ServiceGBUnited Kingdo