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United States Department of Agriculture

Agricultural Research Service

Research Project: WATERSHED LEVEL EXAMINATION OF UREA USE AS FERTILIZER AND THE PRODUCTION OF THE BIOTOXIN DOMOIC ACID

Location: Pasture Systems & Watershed Management Research

Project Number: 1902-13000-012-13
Project Type: Nonfunded Cooperative Agreement

Start Date: Oct 01, 2010
End Date: Aug 31, 2013

Objective:
Characterize the spatial and temporal distribution and co-occurrence of Pseudo-nitzschia sp., domoic acid, urea, and other water quality parameters in relation to surrounding land use to identify probable terrestrial sources of urea in the Manokin River watershed; 2) Determine the effects of agricultural practices on the concentration and distribution of urea entering the surface waters of the Manokin River watershed; 3) Provide educational opportunities to undergraduate and graduate students.

Approach:
Water samples for Pseudo-nitzschia, domoic acid, urea, and other water quality parameters will be collected from 25 selected sites throughout the Maryland Manokin River Watershed. Synoptic water sampling at these sites will be conducted to evaluate concentrations of these water quality parameters and correlations with land-use, time of year, and hydrology. In-stream processing of urea will be evaluated experimentally using standard solute injection techniques. In an exploratory study, we will work with the SPAtially-Referenced Regression on Watershed attributes (SPARROW) model to gain a better understanding of the importance of land-use and in-stream processing on urea export from the Manokin River watershed. Commercial fertilizer or poultry litter use will be documented and spatially characterized throughout the Manokin River watershed. Rainfall simulation studies will be conducted to assess interactions between soil, nitrogen source, and timing/sequence of runoff event on urea losses in runoff using an established indoor runoff box protocol. Column leaching studies will be conducted to assess interactions between soil, nitrogen source, and leaching of urea. Plot and field scale monitoring studies will evaluate fate and transport of urea from agricultural fields to drainage ditches. Graduate and undergraduate students will participate in all aspects of the research.

Last Modified: 4/17/2014
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