Table of Contents
ISRN Ecology
Volume 2011, Article ID 138487, 9 pages
http://dx.doi.org/10.5402/2011/138487
Research Article

Effects of Nitrogen on Temporal and Spatial Patterns of Nitrate in Streams and Soil Solution of a Central Hardwood Forest

1Department of Biological Sciences, Marshall University, Huntington, WV 25755-2510, USA
2Timber and Watershed Laboratory, USDA Forest Service, Parsons, WV 26287, USA

Received 11 January 2011; Accepted 7 February 2011

Academic Editors: D. Gerten and S. Loppi

Copyright © 2011 Frank S. Gilliam and Mary Beth Adams. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study examined changes in stream and soil water N O 3 and their relationship to temporal and spatial patterns of N O 3 in soil solution of watersheds at the Fernow Experimental Forest, West Virginia. Following tenfold increases in stream N O 3 concentrations over a 13-year period (1969–1981) on untreated WS4, concentrations have declined through 2006. Following fourfold increases in stream N O 3 on treatment WS3 from pretreatment levels to a 1998 maximum, concentrations have declined through 2006, despite additions of N. Concentrations of soil water N O 3 were consistently lower for WS4 compared to WS3. Data for soil water N O 3 on WS3 versus WS4 followed patterns of net mineralization and nitrification for these watersheds. Nitrogen additions to WS3 decreased spatial heterogeneity of N processing, which was largest in the pretreatment year and decreased significantly to a minimum by 2000-2001. Concurrently, soil water N O 3 increased on WS3 from 1.3 mg N O 3 -N L−1 in pretreatment 1989 to a maximum of 6.4 mg N O 3 -N L−1 in 2001. Spatial heterogeneity in soil water N O 3 on WS4 remained high during this period. Data suggest that temporal patterns of stream N O 3 may be influenced by spatial heterogeneity of watershed processes which vary over time in response to N availability.