Grunwald,S., Osborne,T.Z. and Reddy,K.R.(2008): Temporal trajectories of phosphorus and pedo-patterns mapped in Water Conservation Area 2, Everglades, Florida, USA. Geoderma, 146, 1-13.

『米国フロリダ州エバーグレイズの水保護地域2で作図されたリンの時間軌跡と土壌パターン』


Abstract
 Documenting local change of soil properties over longer periods of time is critical to assess trends along trajectories. We present two types of temporal trajectories that document change in soil phosphorus (P) and pedo-patterns in Water Conservation Area 2, a subtropical wetland in the Everglades, Florida. Our specific objectives were to (i) quantify the spatial distribution of total P (TP) in floc and topsoil at two time periods (1998 and 2003), (ii) create TP change maps using a crisp, geospatial mapping approach, (iii) analyze relationships between floc/soil TP temporal trajectories and vegetation, and (iv) describe change in pedo-patterns using fuzzy sets to account for the uncertainty inherent in crisp soil property mapping. The median TP in floc was 730 mg kg-1 in 1998 and increased to a median of 751 mg kg-1 in 2003; whereas the median in soil was 485 mg kg-1 in 1998 that decreased to 433 mg kg-1 in 2003. Floc TP change trajectories varied between 0-990 mg kg-1 (increase) and 0-2900 mg kg-1 (decrease); and soil TP change trajectories varied between 0-370 mg kg-1 (increase) and 0-1439 mg kg-1 (decrease). Phosphorus-enriched sites were associated with nutrient influx via surface waters and showed linkages to expanding Typha domengensis vegetation. The temporal trajectories of pedo-patterns provided pixel-specific signatures of ecosystem processes such as P enrichment, organic matter turnover, hydrologic shifts, and fire in form of fuzzy membership values. The fuzzy set-based temporal trajectory maps provided a holistic approach documenting shifts in this ecosystem due to external environmental drivers and biogeochemical processes within a 5-year period.

Keywords: Change analysis; Temporal trajectories; Geospatial analysis; Fuzzy modeling; Crisp modeling』

1. Introduction
2. Methods and materials
 2.1. Study area
 2.2. Sampling and analytical analysis
 2.3. Geospatial analyses and fuzzy c-mean classification
3. Results and discussion
4. Summary and conclusions
Acknowledgements
References


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