title: Leaching of dissolved phosphorus from tile-drained agricultural areas.
abstract: We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss.
authors.affiliation: Department for Bioscience, Aarhus University, Vejlsøvej 25, Silkeborg 8600, Denmark E-mail: hea@bios.au.dk.
authors.forename: H E
authors.initials: HE
authors.lastname: Andersen
authors.affiliation: Department for Bioscience, Aarhus University, Vejlsøvej 25, Silkeborg 8600, Denmark E-mail: hea@bios.au.dk.
authors.forename: J
authors.initials: J
authors.lastname: Windolf
authors.affiliation: Department for Bioscience, Aarhus University, Vejlsøvej 25, Silkeborg 8600, Denmark E-mail: hea@bios.au.dk.
authors.forename: B
authors.initials: B
authors.lastname: Kronvang
mesh_terms: D000822:Animal Husbandry; D003718:Denmark; D004784:Environmental Monitoring; D010758:Phosphorus / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010758:Phosphorus; D012987:Soil; D062065:Wastewater; D014874:Water Pollutants, Chemical