02174nas a2200229   4500008004100000245010200041210006900143300001300212490000700225520140200232653002501634653003101659653003701690653002001727100001901747700001801766700001801784700001901802700002001821700001601841856008701857       2010                        eng d00aPhosphorus biogeochemistry across a precipitation gradient in grasslands of central North America0 aPhosphorus biogeochemistry across a precipitation gradient in gr  a954 -9610 v743 a<p>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.</p>10aGrassland ecosystems10aPhosphorus biogeochemistry10aSequential phosphorus extraction10aSoil weathering1 aIppolito, J.A.1 aBlecker, S.W.1 aFreeman, C.L.1 aMcCulley, R.L.1 aBlair, John, M.1 aKelly, E.F.  uhttps://www.sciencedirect.com/science/article/abs/pii/S014019631000011X?via%3Dihub