Phosphorus Retention in Riparian Buffers: Review of Their Efficiency
- Carl Christian Hoffmann *a,
- Charlotte Kjaergaardb,
- Jaana Uusi-Kämppäc,
- Hans Christian Bruun Hansend and
- Brian Kronvanga
- a Aarhus Univ., National Environmental Research Institute, Dep. of Freshwater Ecology, Vejlsoevej 25, DK8600 Silkeborg, Denmark
b Aarhus Univ., Faculty of Agricultural Sciences, Dep. of Agroecology and Environment, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark
c MTT Agrifood Research Finland, Plant Production Research, Soil and Plant Nutrition, E-talo, FI-31600 Jokioinen, Finland
d Dep. of Basic Sciences and Environment, Faculty of Life Sciences, Univ. of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
Ground water and surface water interactions are of fundamental importance for the biogeochemical processes governing phosphorus (P) dynamics in riparian buffers. The four most important conceptual hydrological pathways for P losses from and P retention in riparian buffers are reviewed in this paper: (i) The diffuse flow path with ground water flow through the riparian aquifer, (ii) the overland flow path across the riparian buffer with water coming from adjacent agricultural fields, (iii) irrigation of the riparian buffer with tile drainage water from agricultural fields where disconnected tile drains irrigate the riparian buffer, and (iv) inundation of the riparian buffer (floodplain) with river water during short or longer periods. We have examined how the different flow paths in the riparian buffer influence P retention mechanisms theoretically and from empirical evidence. The different hydrological flow paths determine where and how water-borne P compounds meet and interact with iron and aluminum oxides or other minerals in the geochemical cycling of P in the complex and dynamic environment that constitutes a riparian buffer. The main physical process in the riparian buffer—sedimentation—is active along several flow paths and may account for P retention rates of up to 128 kg P ha−1 yr−1, while plant uptake may temporarily immobilize up to 15 kg P ha−1 yr−1 Retention of dissolved P in riparian buffers is not as pronounced as retention of particulate P and is often below 0.5 kg P ha−1 yr−1 Several studies show significant release of dissolved P (i.e., up to 8 kg P ha−1 yr−1).Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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