High flow event induced the subsurface transport of particulate phosphorus and its speciation in agricultural tile drainage system

• Published in: Chemosphere (Oxford) Vol. 263; no. C; p. 128147
• Main Authors: Jiang, Xiaoqian, Livi, Kenneth J.T., Arenberg, Mary R., Chen, Ai, Chen, Kai-yue, Gentry, Lowell, Li, Zhe, Xu, Suwei, Arai, Yuji
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-01-2021; Elsevier
• Subjects: Agriculture; Colloid; Particulate P; Phosphorus (P); Phosphorus - analysis; Soil; Speciation; Subsurface transport; Water Movements; Water Quality; Phosphorus (P); Subsurface transport; Particulate P; Speciation; Colloid
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.128147

Subsurface storm flow of phosphorus (P), including particulate P, has been recently discussed as an important P transport path in contrast to typical surface runoff events. However, P speciation, and P concentration during storm events has not been extensively investigated; therefore, its contribution to the water quality is not clearly understood. In this study, the physicochemical properties of particulate P in tile water samples during a high flow event were investigated in Midwestern agricultural lands using wet chemical methods, 31P Nuclear Magnetic Resonance spectroscopy and P K-edge X-ray absorptions near edge structure spectroscopy.
In slightly alkaline pH tile water, total P was ranging from ∼0.06 to 0.22 mg L−1, which is significantly greater than dissolved reactive P (DRP) (∼0.02–0.08 mg L−1). The tile water contains P enriched particulate matters (∼200–660 mg L−1). Total P in the colloidal fraction was from 1013 to 2270 mg kg−1. Phosphate and organic P species, especially monoesters, are sorbed in soil colloids like calcite, and iron oxides, and colloids are effective carriers of P in the subsurface transport process during storm events. The results of this study show that storm events can accelerate the subsurface transport of P with soil particles in addition to DRP.
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•Storm flow induced P release was monitored in agricultural tile waters.•The release of TP in particulate P was far greater than DRP during storm events.•The concentration of DRP exceeds the eutrophication inducible P level.•Both organic and inorganic P were equally important P species in particulate P.•Phosphorus is enriched in iron oxyhydroxide nanoclusters in tile waters.