Phosphorus biogeochemistry across a precipitation gradient in grasslands of central North America

作者：Ippolito J A^*; Blecker S W; Freeman C L; McCulley R L; Blair J M; Kelly E F

来源：Journal of Arid Environments, 2010, 74(8): 954-961.

DOI：10.1016/j.jaridenv.2010.01.003

• Grassland ecosystems
• Phosphorus biogeochemistry
• Sequential phosphorus extraction
• Soil weathering

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 CaCO(3), while in subsurface horizons the Ca-bound P was associated with increasing CaCO(3) 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 Published by Elsevier Ltd

• 出版日期2010-8