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A Spatially Explicit Investigation of Phosphorus Sorption and Related Soil Properties in Two Riparian Wetlands
Author(s) -
Bruland Gregory L.,
Richardson Curtis J.
Publication year - 2004
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2004.7850
Subject(s) - sorption , silt , environmental science , soil water , soil science , riparian zone , semivariance , geostatistics , spatial variability , soil texture , wetland , biogeochemical cycle , environmental chemistry , soil organic matter , organic matter , hydrology (agriculture) , chemistry , geology , ecology , geomorphology , statistics , mathematics , geotechnical engineering , organic chemistry , adsorption , habitat , biology
Soils of riparian wetlands are highly effective at phosphorus (P) sorption. However, these soils exhibit extreme spatial variability across riparian zones. We used a spatially explicit sampling design in two riparian wetlands in North Carolina to better understand the relationships among P sorption, soil properties, and spatial variability. Our objectives were to quantify patterns of spatial variability of P sorption and related soil properties, and to determine which soil properties best explained the variability in P sorption after accounting for the effects of spatial autocorrelation. We measured bulk density, moisture, pH, soil organic matter (SOM), texture (percent clay, silt, and sand), oxalate‐extractable aluminum (Al ox ), iron (Fe ox ), and the phosphorus sorption index (PSI). Due to differences in texture, Al ox , and Fe ox , the two sites had substantially different mean PSIs. At each site, we found considerable differences in the spatial variability of soil properties. For example, semivariance analysis and kriging illustrated that soil properties at Site 1 varied at smaller scales than those at Site 2. At both sites, after accounting for the effects of spatial autocorrelation and all other soil properties, we determined that Al ox had the highest Mantel correlation with PSI. We believe this geostatistic and Mantel approach is robust and could serve as a model for research on other biogeochemical processes such as denitrification.