%0 Journal Article %J Journal of Arid Environments %D 2010 %T Phosphorus biogeochemistry across a precipitation gradient in grasslands of central North America %A Ippolito, J.A. %A Blecker, S.W. %A Freeman, C.L. %A McCulley, R.L. %A John M. Blair %A Kelly, E.F. %K Grassland ecosystems %K Phosphorus biogeochemistry %K Sequential phosphorus extraction %K Soil weathering %X

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.

%B Journal of Arid Environments %V 74 %P 954 -961 %G eng %U https://www.sciencedirect.com/science/article/abs/pii/S014019631000011X?via%3Dihub %M KNZ001301 %R 10.1016/j.jaridenv.2010.01.003