Year: 2025
Type: article
Abstract: Resin‐extractable phosphate (PO4‐P) is a widespread sink‐based measure of soil bioavailable phosphorus (P) used in biogeochemistry and soil fertility. However, acid elution of P may hydrolyze organic P and thus compromise measurement of PO4‐P. We evaluated sodium bicarbonate (NaHCO3) as an alternative to sulfuric acid (H2SO4) for PO4‐P elution. We found 0.5 M NaHCO3 achieved ≈100% PO4‐P recovery at higher initial PO4‐P concentrations (20 and 30 mg P/L), compared to 95%–98% with 0.25 M H2SO4. For 24 soil samples representing all 12 USDA soil orders, NaHCO3 elution yielded 9.6% higher resin extractable PO4‐P than H2SO4. Additionally, the PO4‐P remaining in water extract after resin removal (H2Ore‐PO4) was consistently quantifiable, and constituted up to 46% of total extractable PO4‐P. These results demonstrate (i) NaHCO3 is a more effective eluent for resin extractable P than H2SO4, and (ii) H2Ore‐PO4 should be quantified when measuring resin extractable P.
DOI: 10.1002/ael2.70012
Authors: Suwei Xu, Andrew J. Margenot
Institution: University of Illinois Urbana-Champaign
Language: English
Subfield: Waste Management and Disposal
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,900
OpenAlex ID: W4407227161