Abstract

Agriculture is a major source of sediment and particulate phosphorus (P) inputs to freshwaters. Distinguishing between P fractions in sediment can aid in understanding its eutrophication risk. Although streams and rivers are important parts of the P cycle in agricultural catchments, streambed sediment and especially fluvial suspended sediment (FSS) and its P fractions are less studied. To address this knowledge gap, seasonal variations in FSS P fractions and their relation to water quality and streambed sediment were examined in three Swedish agricultural headwater catchments over 2 yr. Sequential fractionation was used to characterize P fractions in both streambed sediment and FSS. All catchments had similar annual P losses (0.4-0.8 kg ha(-1)), suspended solids (124-183 mg L-1), and FSS total P concentrations (1.15-1.19 mg g(-1)). However, distribution of P fractions and the dominant P fractions in FSS differed among catchments (p < .05), which was most likely dependent on differences in catchment geology, clay content, external P sources, and flow conditions. The most prominent seasonal pattern in all catchments was found for iron-bound P, with high concentrations during low summer flows and low concentrations during winter high flows. Streambed sediment P fractions were in the same concentration ranges as in FSS, and the distribution of the fractions differed between catchments. This study highlights the need to quantify P fractions, not just total P in FSS, to obtain a more complete understanding of the eutrophication risk posed by agricultural sediment losses.

Published in

Journal of Environmental Quality
2021, Volume: 50, number: 3, pages: 612-626
Publisher: WILEY

SLU Authors

• Sandström, Sara

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Futter, Martyn

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Lannergård, Emma

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Rakovic, Jelena

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Kyllmar, Katarina

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Djodjic, Faruk

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all


UKÄ Subject classification

Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1002/jeq2.20210

Permanent link to this page (URI)

https://res.slu.se/id/publ/111671