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Sample Pretreatment and Phosphorus Speciation in Wetland Soils
Author(s) -
Turner Benjamin L.,
Newman Susan,
Cheesman Alexander W.,
Reddy K. Ramesh
Publication year - 2007
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2007.0017
Subject(s) - soil water , extraction (chemistry) , chemistry , benthic zone , phosphorus , environmental chemistry , genetic algorithm , soil test , calcareous , wetland , chromatography , botany , biology , ecology , organic chemistry
We assessed the influence of sample pretreatment on the amounts and forms of P extracted in NaOH–EDTA (ethylenediamine tetraacetic acid) from a series of contrasting wetland soils from the Florida Everglades. Samples of unconsolidated benthic floc and underlying soil (0–10 cm) were extracted either fresh (overnight refrigeration only), air dried (10 d at ∼30°C), or frozen at −80°C and lyophilized (∼48 h), before extraction and solution 31 P nuclear magnetic resonance (NMR) spectroscopy. Significant differences in total P extraction following pretreatment were detected for one out of four benthic floc samples and three out of four soil samples, although the changes were inconsistent: in two cases the total P extraction increased, while in two others it decreased. Assessment of the P composition by solution 31 P NMR spectroscopy revealed differences among treatments, although these were mostly within the range of error associated with replicate analyses; however, DNA was not detected in a fresh sample of calcareous benthic floc, despite representing an important component of the organic P extracted from dried samples. The apparent sample‐specific nature of the changes confirms the importance of carefully assessing pretreatment effects in studies of soil organic P in wetlands.