『Abstract
　The Florida Everglades wetland ecosystem is subject to changes in hydroperiod and nutrient loading, resulting in soil P enrichment and changes in vegetation communities. The objectives of this study were to: (i) quantify the forms of inorganic and organic P in soils from four hydrologic units of the Everglades, and (ii) develop empirical relationships among various soil P forms. Solid samples from selected hydrologic units, including the Water Conservation Areas (WCAs) and the Holey Land Wildlife Management Area (HWMA), were obtained at various locations along transects perpendicular to each nutrient input source, while selected field sites were sampled in the Everglades Agricultural Area (EAA). Spatial distribution of total P in the surface 0- to 10-cm soil depth showed distinct gradients in the WCAs and HWMA soils, with high total P in soils closer to sources (canals and inflow structures) than in interior, unimpacted areas. Soil ash content and bulk density were also altered as a result of soil subsidence (for EAA soils), hydrology, and nutrient loading (for the WCAs and the HWMA soils). Influence of P loading was primarily confined to the top 30-cm soil depth, with about one-third of the P stored in the inorganic pool (primarily as Ca- and Mg-bound P), and the remainder present as organic P. Inorganic P content was higher in surface soils and decreased with depth. Soil P enrichment indicated that for approximately 5 km from the inflow structures or canals, soils have been impacted by nutrient loading. Empirical relationships developed in this study should be useful for estimating soil P forms at the landscape level, using total P data available for a large number of sites throughout the Everglades region.』

Abbreviations
(Introduction)
Materials and methods
　Site description
　Sampling and analysis
　Soil phosphorus fractionation
　　Potassium chloride extractable phosphorus
　　Sodium hydroxide extractable phosphorus
　　Hydrochloric acid extractable P
　　Residual phosphorus and total phosphorus
　　Bicarbonate-extractable phosphorus
　　Microbial biomass phosphorus
　　Total labile organic phosphorus
　　Hydrochloric acid extractable phosphorus and cations
　Data analysis
Results
　Soil phosphorus forms
　　Labile inorganic phosphorus
　　Sodium hydroxide extractable phosphorus (iron- and Aluminum-bound phosphorus)
　　Hydrochloric acid-extractable inorganic phosphorus (calcium- and magnesium-bound phosphorus)
　　Total inorganic phosphorus
　　Total labile organic phosphorus and microbial biomass phosphorus
　　Sodium hydroxide extractable organic phosphorus
　　Residual organic phosphorus
　　Total organic phosphorus
　Phosphorus storage
　Empirical relationships
Discussion
Conclusions
Acknowledgments
References