An Application of Autoradiography to Study the Spacial Distribution of ³³P‐Labelled Orthophosphate Added to Soil Crumbs

Abstract

The penetration of orthophosphate (P) into soil crumbs was studied semiquantitatively using 31P, the low energy isotope 33P, autoradiography on a medium grained film, and solution analysis. Sorption of added P by the soil crumbs was rapid and was followed by penetration. Phosphate was not concentrated in discrete areas, suggesting that it was retained by a sorption rather than a precipitation mechanism. Native and added P, isotopically exchangeable in 1 hour, were confined to the crumb surface. Desorption for 7 days in Cl‐ or SO42‐ had little or no effect on the spacial distribution of sorbed added P; 0 and 2.4% of the sorbed added 31P was desorbed by Cl‐ and SO42‐, respectively. Desorption in HCO3‐ or citrate increased the mobility of sorbed added P resulting in a complete redistribution within the crumbs and release into solution of 14 to 18% or 10 to 61% of sorbed added 31P, respectively. Anomalous estimates of the amount of P sorbed or desorbed, obtained by 31P and 33P analyses, could not always be explained by isotopic exchange.

Phosphorus biogeochemistry across a precipitation gradient in grasslands of central North America

“…The non-calcareous extraction procedure identified soluble and loosely bound, Al oxyhydroxide-surface bound, Fe oxyhydroxide-surface bound, occluded (within the matrices of retaining components/minerals (Evans and Syers, 1971)), and Cabound mineral P fractions. The calcareous extraction procedure identified soluble and loosely bound/Al-bound/Fe-bound, occluded, and Ca-bound mineral P fractions.…”

Phosphorus sorption–desorption in alluvial soils of a young weathering sequence at the Danube River

“…Main phosphate-sorbing soil surfaces are those of Al and Fe oxides, hydroxides, and oxyhydroxides -which are collectively referred to as oxides - (Torrent, 1997), organic complexes of Al and Fe (Borggaard et al, 2004), edges of silicate clays, and calcite (Matar et al, 1992). After the initial adsorption, P can become less labile with time, perhaps by diffusive penetration of adsorbed phosphate ions into the internal structure of components (Evans and Syers, 1971;Pierzynski, 1991).…”

Aluminum-Based Water Treatment Residual Use in a Constructed Wetland for Capturing Urban Runoff Phosphorus: Column Study

“…Greater P concentrations in the soluble + Al + Fe-bound fraction were also a result of P being bound to amorphous Al phases, as shown by others (e.g., Ippolito et al 2003;Makris et al 2005). Greater P content in the occluded phase represents greater P within retaining components or minerals (Evans and Syers 1971). Bayley et al (2008) studied short-and long-term Al-WTR applications to a shortgrass steppe rangeland soil, showing that Al-WTR contributed to increased P content in the occluded phase as well as the soluble + Al + Fe-bound phase.…”