Paper No. 96017 of the Water Resources Bulletin. Discussions are open until June 1, 1997.
DISTRIBUTION OF NITRATE AND ORTHOPHOSPHATE IN SELECTED STREAMS IN CENTRAL NEBRASKA1
Version of Record online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 32, Issue 6, pages 1247–1257, December 1996
How to Cite
Boyd, R. A. (1996), DISTRIBUTION OF NITRATE AND ORTHOPHOSPHATE IN SELECTED STREAMS IN CENTRAL NEBRASKA. JAWRA Journal of the American Water Resources Association, 32: 1247–1257. doi: 10.1111/j.1752-1688.1996.tb03494.x
- Issue online: 8 JUN 2007
- Version of Record online: 8 JUN 2007
- water quality;
- Platte River;
- surface-water hydrology;
- agricultural hydrology;
- orthophos. phate
ABSTRACT: The Central Nebraska Basins is one of 60 study units in the National Water-Quality Assessment Program of the U.S. Geological Survey. The study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Agriculture is the predominant land use in the study unit, with only eight urbanized communities exceeding a population of 10,000. Water samples were collected from selected streams in the study unit during 1993–1995. The data were used to assess the distribution of nitrogen compounds and phosphorus in the streams and to relate the concentrations of these constituents to environmental settings. This article focuses on dissolved nitrate and orthophosphate. Dissolved nitrate concentrations were highest (90th percentiles were less than 7.0 milligrams per liter as nitrogen) in areas with extensive cropland and pasture, where chemical fertilizers are intensively applied. Synoptic measurements conducted in March and August 1994 indicate that relatively little residual fertilizer, as nitrate, applied during a single crop-growing season enters streams. Dissolved nitrate concentrations showed a seasonal pattern, being highest during winter months and lowest during the late spring and summer. Dissolved orthophosphate concentrations tended to be low across the study unit, 90 percent of all analyses did not exceed 1.7 milligrams per liter as phosphorus.