Journal article
Linking Dissolved and Particulate Phosphorus Export in Rivers Draining California's Central Valley with Anthropogenic Sources at the Regional Scale
Journal of environmental quality, Vol.40(4), pp.1290-1302
07/01/2011
PMID: 21712599
Abstract
Pollution of water resources by phosphorus (P) is a critical issue in regions with agricultural and urban development. In this study, we estimated P inputs from agricultural and urban sources in 24 catchments draining to the Central Valley in California and compared them with measured river P export to investigate hydrologic and anthropogenic factors affecting regional P retention and export. Using spatially explicit information on fertilizer use, livestock population, agricultural production, and human population, we calculated that net surface balances for anthropogenic P ranged from -12 to 648 kg P km(-2) yr(-1) in the early 2000s. Inorganic P fertilizer and manure P comprised the largest fraction of total input for all but two catchments. From 2000 to 2003, a median of 7% (range, -287 to 88%) of net annual anthropogenic P input was exported as total P (TP). Yields (kg P km(-2) yr(-1)) of dissolved inorganic P (DIP), dissolved organic P, particulate P, and TP were not significantly related to catchment-level, per area anthropogenic P input. However, there were significant relationships between mean annual P concentrations and P input from inorganic fertilizers and manure due to the concentration of agricultural land near catchment mouths and regional variation in runoff. Catchment-level P fertilizer and manure inputs explained 4 to 23% more variance in mean annual DIP and TP concentrations than percent of catchment area in agriculture. This study suggests that spatially explicit estimates of anthropogenic P input can help identify sources of multiple forms of P exported in rivers at management-relevant spatial scales.
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Details
- Title
- Linking Dissolved and Particulate Phosphorus Export in Rivers Draining California's Central Valley with Anthropogenic Sources at the Regional Scale
- Creators
- Daniel J Sobota - Washington State Univ, Sci Programs, Vancouver, WA 98686 USAJohn A Harrison - Washington State University, Environment, School of the (CAS)Randy A Dahlgren - University of California, Davis
- Publication Details
- Journal of environmental quality, Vol.40(4), pp.1290-1302
- Academic Unit
- Environment, School of the (CAS)
- Publisher
- AMER SOC AGRONOMY
- Number of pages
- 13
- Grant note
- RSF8 / California Sea Grant USFW NASA USBR USGS
- Identifiers
- 99900667382301842
- Language
- English
- Resource Type
- Journal article