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

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ruark, M. D. Articles by Turco, R. F. Search for Related Content PubMed PubMed Citation Articles by Ruark, M. D. Articles by Turco, R. F. Agricola Articles by Ruark, M. D. Articles by Turco, R. F. Related Collections Water Quality Surface Water Quality Organic Compounds Agricultural Systems Animal Waste

TECHNICAL REPORTS

Surface Water Quality

Dissolved Organic Carbon Losses from Tile Drained Agroecosystems

^a Dep. of Soil Science, Univ. of Wisconsin-Madison, 1525 Observatory Dr., Madison, WI, 53706
^b Dep. of Agronomy, Purdue Univ., 915 W. State St., West Lafayette, IN 47907

^* Corresponding author (mdruark{at}wisc.edu).

Received for publication March 6, 2008. Artificial subsurface drainage is commonly used in midwestern agriculture and drainage losses of dissolved organic carbon (DOC) from such systems are an under-quantified portion of the terrestrial carbon (C) cycle. The objectives of this study were to determine the effect of common agricultural management practices on DOC losses from subsurface tile drains and to assess patterns of loss as a function of year, time of year, and drainflow. Daily drainflow was collected across six water years (1999–2004) from a restored prairie grass system and cropping systems which include continuous corn (Zea mays L.) and corn-soybean [Glycine max (L.) Merr.] rotations fertilized with urea-ammonium-nitrate (UAN) or swine (Sus scrofa) manure lagoon effluent. The DOC concentrations in tile drainflow were low, typically <2 mg L^–1. Yearly DOC losses, which ranged from 1.78 to 8.61 kg ha^–1, were not affected by management practices and were small compared to organic C inputs. Spring application of lagoon effluent increased yearly flow-weighted (FW)-DOC concentrations relative to other cropping systems in three of the years and increased monthly FW-DOC concentrations when drainflow occurred within 1 mo of application. Drainflow was significantly and positively correlated with DOC loss. Drainflow also affected DOC concentrations as greater 6-yr cumulative drainflow was associated with lower 6-yr FW-DOC concentrations and greater daily drainflow was associated with higher daily DOC concentrations. Our results indicate that lagoon effluent application and fertilizer N rates do not affect long-term losses of DOC from tile drains and that drainflow is the main driver of DOC losses.

Abbreviations: C, carbon • DOC, dissolved organic carbon • FW, flow-weighted • LOI, loss on ignition • N, nitrogen • SOC, soil organic carbon • TDE, tile drain efficiency • UAN, urea-ammonium-nitrate • WQFS, water quality field station