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Phosphorus Biogeochemistry Across a Precipitation Gradient in Grasslands of Central North America

Ippolito, J.A. and Blecker, S.W. and Freeman, C.L. and McCulley, R.L. and Blair, J.M. and Kelly, E.F. (2010) Phosphorus Biogeochemistry Across a Precipitation Gradient in Grasslands of Central North America. Journal of Arid Environments. 74:954-961.

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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 grassdominated 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.

Item Type: Article
NWISRL Publication Number: 1353
Subjects: Soil
Soil > Chemistry > Phosphorous
Soil > Chemistry
Depositing User: Users 6 not found.
Date Deposited: 26 May 2010 01:37
Last Modified: 21 Nov 2010 22:33
Item ID: 1370