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 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 Oquist, K. A. Articles by Mulla, D. J. Search for Related Content PubMed PubMed Citation Articles by Oquist, K. A. Articles by Mulla, D. J. Agricola Articles by Oquist, K. A. Articles by Mulla, D. J. Related Collections Water Quality Crop Rotation Systems

TECHNICAL REPORTS

Surface Water Quality

Influence of Alternative and Conventional Farming Practices on Subsurface Drainage and Water Quality

^a Mississippi Watershed Management Organization, 2520 Larpenteur Ave. W., Lauderdale, MN 55113
^b Southwest Research and Outreach Center, Univ. of Minnesota, 23669 130th St., Lamberton, MN 56152
^c Dep. of Soil, Water, and Climate, Univ. of Minnesota, 1991 Upper Buford Circle, St. Paul, MN 55108

^* Corresponding author (jstrock{at}umn.edu)

Received for publication July 14, 2006. Agricultural runoff contributes nutrients to nonpoint-source pollution of surface waters. This study was conducted to investigate the potential use of alternative farming practices to improve water quality. The study examined the effects of both alternative and conventional farming practices on subsurface drainage and nitrogen and phosphorus loss through subsurface drainage from glacial till soils (i.e., Calciaquolls, Endoaquolls, Eutrudepts, Hapludolls) in southwest Minnesota. Alternative farming practices included organic management practices, species biodiversity, and/or practices that include reduced inputs of synthetic fertilizer and pesticides. Conventional farming practices include corn–soybean (Zea mays L.–Glycine max L., respectively) rotations and their associated recommended fertilizer rates as well as pesticide usage. Precipitation was highly variable during the 3-yr study period including a below-average year (2003), an average year (2002), and an above-average year (2004). Results indicate that alternative farming practices reduced subsurface drainage discharge by 41% compared with conventional practices. Flow-weighted mean nitrate-nitrogen (nitrate N) concentrations during tile flow were 8.2 and 17.2 mg L^–1 under alternative and conventional farming practices, respectively. Alternative farming practices reduced nitrate N losses by between 59 and 62% in 2002 and 2004 compared with conventional practices. Ammonium-nitrogen (ammonium N), orthophosphorus, and total phosphorus losses in subsurface drainage were very low and did not pose a substantial risk of pollution. Results suggest that alternative farming practices have the potential to reduce agricultural impacts on water quality.

Abbreviations: AL, alternative • ammonium N, ammonium-nitrogen • CN, conventional • NH₄, ammonium-nitrogen • nitrate N, nitrate-nitrogen • NO₃, nitrate-nitrogen • OP, orthophosphorus • TP, total phosphorus