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Anoxia-induced release of colloid and nanoparticle-bound phosphorus in grassland soils.
MedLine Citation:
PMID:  23017121     Owner:  NLM     Status:  Publisher    
Particle facilitated transport is a key mechanism of phosphorus (P) loss in agroecosystems. We assessed contributions of colloid and nanoparticle-bound P (nPP; 1 nm - 415 nm) to total P released from grassland soils receiving bi-annual poultry litter applications since 1995. In laboratory incubations, soils were subjected to 7 days of anoxic conditions or equilibrated at pH 6 and 8 under oxic conditions and then the extract was size fractionated by differential centrifugation/ultrafiltration for analysis of P, Al, Fe, Si, Ti, and Ca. Selected samples were characterized by transmission electron microscopy energy dispersive spectroscopy (TEM-EDS) and field flow fractionation (FFF-ICP-MS). Particles released were present as nano-aggregates with a mean diameter of 200 - 250 nm, composed of ~50 nm aluminosilicate flakes studded with Fe and Ti-rich clusters (<10 nm) that contained most of the P detected by EDS. Anoxic incubation of stimulated nPP release with seasonally saturated soils releasing more nPP and Fe2+(aq) than well-drained soils; whereas, non-reductive particle dispersion, accomplished by raising the pH, yielded no increase in nPP release. This suggests Fe acts as a cementing agent, binding to the bulk soil P-bearing colloids that can be released during reducing conditions. Furthermore, it suggests prior periodic exposure to anoxic conditions increases susceptibility to redox-induced P mobilization.
Russell Henderson; Nadine Kabengi; Nehru Mantripragada; Miguel Cabrera; Sayed Hassan; Aaron Thompson
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-9-28
Journal Detail:
Title:  Environmental science & technology     Volume:  -     ISSN:  1520-5851     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-9-28     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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