Journal article
Orthophosphorus Contributions to Total Phosphorus Concentrations and Loads in Iowa Agricultural Watersheds
Journal of environmental quality, Vol.46(4), pp.828-835
07/2017
DOI: 10.2134/jeq2017.01.0015
PMID: 28783777
Abstract
Phosphorus (P) is delivered to streams as episodic particulate P and more continuous soluble P (orthophosphorus [OP]), and it is important to determine the proportion of each P form in river water to more effectively design remedial measures. In this study, we evaluated the annual mean ratios of OP to total P (TP) concentrations and loads in 12 Iowa rivers and found systematic variation in the ratios. The OP/TP ratios were > 60% in two tile-drained watersheds of the Des Moines Lobe and in a shallow fractured bedrock watershed in northeast Iowa, whereas in southern and western Iowa, OP contributions to TP were < 30%. Higher OP/TP ratios were associated with greater row crop intensity in the watershed and a greater proportion of baseflow in the river. Orthophosphorus contributions from croplands would be greater in watersheds characterized by widespread tile drainage and well-drained soils, whereas cropland TP export would be dominated by particulate P in dissected till plains with poorly drained soils. Understanding the dominant form and transport pathway of P from agricultural areas in a watershed is seen as an important first step in determining appropriate conservation practices to reduce P loads.
Details
- Title: Subtitle
- Orthophosphorus Contributions to Total Phosphorus Concentrations and Loads in Iowa Agricultural Watersheds
- Creators
- Keith E. Schilling - Iowa Geological Survey, 300 Trowbridge Hall, Univ. of Iowa, Iowa City, IA 52242Sea-Won Kim - University of IowaChristopher S. Jones - University of IowaCalvin F. Wolter - Iowa Department of Natural Resources
- Resource Type
- Journal article
- Publication Details
- Journal of environmental quality, Vol.46(4), pp.828-835
- Publisher
- Amer Soc Agronomy
- DOI
- 10.2134/jeq2017.01.0015
- PMID
- 28783777
- ISSN
- 0047-2425
- eISSN
- 1537-2537
- Number of pages
- 8
- Language
- English
- Date published
- 07/2017
- Academic Unit
- Earth and Environmental Sciences; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984383908902771
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