HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Bedard-Haughn, A. Articles by van Kessel, C. Search for Related Content PubMed PubMed Citation Articles by Bedard-Haughn, A. Articles by van Kessel, C. Agricola Articles by Bedard-Haughn, A. Articles by van Kessel, C. Related Collections Surface Water Quality Runoff Best Management Practices Isotopes Nitrogen

TECHNICAL REPORTS

Surface Water Quality

Using Nitrogen-15 to Quantify Vegetative Buffer Effectiveness for Sequestering Nitrogen in Runoff

Department of Agronomy and Range Science, University of California, Davis, CA 95616

^* Corresponding author (bedardhaughn{at}ucdavis.edu)

Received for publication February 18, 2004. Previous studies have observed higher levels of soluble nutrients leaving vegetative buffers than entering them, suggesting that the buffers themselves are acting as a source rather than a sink by releasing previously stored nutrients. This study used 98 atom % ¹⁵N-labeled KNO₃ at a rate of 5 kg ha^–1 to quantify buffer efficiency for sequestering new inputs of NO^–₃–N in an extensively grazed irrigated pasture system. Buffer treatments consisted of an 8-m buffer, a 16-m buffer, and a nonbuffered control. Regardless of the form of runoff N (NO^–₃, NH⁺₄, or dissolved organic nitrogen [DON]), more ¹⁵N was lost from the nonbuffered treatments than from the buffered treatments. The majority of the N attenuation was by vegetative uptake. Over the course of the study, the 8-m buffer decreased NO^–₃–¹⁵N load by 28% and the 16-m buffer decreased load by 42%. For NH⁺₄–¹⁵N, the decrease was 34 and 48%, and for DON–¹⁵N, the decrease was 21 and 9%. Although the buffers were effective overall, the majority of the buffer impact occurred in the first four weeks after ¹⁵N application, with the buffered plots attenuating nearly twice as much ¹⁵N as the nonbuffered plots. For the remainder of the study, buffer effect was not as marked; there was a steady release of ¹⁵N, particularly NO^–₃– and DON–¹⁵N, from the buffers into the runoff. This suggests that for buffers to be sustainable for N sequestration there is a need to manage buffer vegetation to maximize N demand and retention.

Abbreviations: DON, dissolved organic nitrogen

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2004 33: 1947-1953. [Full Text]  

This article has been cited by other articles:

				K. W. Tate, E. R. Atwill, J. W. Bartolome, and G. Nader Significant Escherichia coli Attenuation by Vegetative Buffers on Annual Grasslands J. Environ. Qual., April 3, 2006; 35(3): 795 - 805. [Abstract] [Full Text] [PDF]

				A. Bedard-Haughn, K. W. Tate, and C. van Kessel Quantifying the Impact of Regular Cutting on Vegetative Buffer Efficacy for Nitrogen-15 Sequestration J. Environ. Qual., August 9, 2005; 34(5): 1651 - 1664. [Abstract] [Full Text] [PDF]