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Phosphorus Biogeochemistry across a Precipitation Gradient in Grasslands of Central North America
Journal of Arid Environments (2010)
  • J. A. Ippolito
  • S. W. Blecker, Colorado State University
  • C. L. Freeman, Colorado State University
  • Rebecca L. McCulley, University of Kentucky
  • J. M. Blair, Kansas State University
  • E. F. Kelly, Colorado State University

Soil P transformations and distribution studies under water limited conditions that characterize many grasslands may provide further insight into the importance of abiotic and biotic P controls within grass-dominated ecosystems. We assessed transformations between P pools across four sites spanning the shortgrass steppe, mixed grass prairie, and tallgrass prairie along a 400-mm precipitation gradient across the central Great Plains. Pedon total elemental and constituent mass balance analyses reflected a pattern of increased chemical weathering from the more arid shortgrass steppe to the more mesic tallgrass prairie. Soil surface A horizon P accumulation was likely related to increased biocycling and biological mining. Soluble P, a small fraction of total P in surface A horizons, was greatest at the mixed grass sites. The distribution of secondary soil P fractions across the gradient suggested decreasing Ca-bound P and increasing amounts of occluded P with increasing precipitation. Surface A horizons contained evidence of Ca-bound P in the absence of CaCO3, while in subsurface horizons the Ca-bound P was associated with increasing CaCO3 content. Calcium-bound P, which dominates in water-limited systems, forms under different sets of soil chemical conditions in different climatic regimes, demonstrating the importance of carbonate regulation of P in semi-arid ecosystems.

  • Grassland ecosystems,
  • Phosphorus biogeochemistry,
  • Sequential phosphorus extraction,
  • Soil weathering
Publication Date
August, 2010
Citation Information
J. A. Ippolito, S. W. Blecker, C. L. Freeman, Rebecca L. McCulley, et al.. "Phosphorus Biogeochemistry across a Precipitation Gradient in Grasslands of Central North America" Journal of Arid Environments Vol. 74 Iss. 8 (2010)
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