Short-term effects of mechanical weeding on soil and tissue N in snap beans grown in an organic vs. conventional rotations

Josée Owen¹*, Serge LeBlanc¹, Sherry A. E. Fillmore²

Abstract
Mechanical weeding, a common practice in organic crop production, causes frequent soil disturbance. This study, conducted from 2003 to 2005 in an organic vs. conventional rotations experiment in New Brunswick, examined changes in available soil N and in tissue N of snap beans following mechanical weeding events.

The experimental design included continuous snap beans, and a fully phased snap beans/fall rye rotation, to which combinations of yearly applied fertility (chemical fertilizer or compost) and weed control (herbicide or mechanical weeding) were applied. Two mechanical weedings were performed each season. Plant available soil N was monitored by 24-hour burials of ion exchange membranes beginning 12 hours after weeding in both mechanically-weeded and herbicide-treated plots. Ions were eluted from the membranes and analysed. Coinciding with membrane removal from the soil, aerial bean plant parts were collected for total tissue N analysis.

Availability of soil NH₄⁺-N was not affected by weeding treatment. Soil NO₃^--N availability, however, was consistently less in mechanically weeded plots than in plots treated with herbicide. Weeding method affected tissue N, and interacted significantly with rotation. Scattergrams of treatment means plotted as total tissue N vs available soil N revealed these interactions as distinct groupings.

See the Full Presentation (PDF). Also see a Poster from Colloquium of Organic Research (COR) 2006. Edinburgh, Scotland. September 18-20, 2006.

Source
Oral Presentation. Organic Research Symposium, Guelph, Ontario, January 26, 2007.

Author Locations and Affiliations
(1) Agriculture and Agri-Food Canada, Senator Hervé J. Michaud Research Farm, P.O. Box 2069, Bouctouche NB E4S 4J1
(2) Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre, 32 Main Street, Kentville NS B4N 1J5

en français

Posted October 2007


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Research Extension Courses Consumers -------------------------- Virtual Tours Student & Job Opportunities News Articles Standards -------------------------- Market Information Events Issues Animal Welfare Strategic Plans -------------------------- Links Award-winners Site Map	Short-term effects of mechanical weeding on soil and tissue N in snap beans grown in an organic vs. conventional rotations *Josée Owen¹, Serge LeBlanc¹, Sherry A. E. Fillmore² Abstract** Mechanical weeding, a common practice in organic crop production, causes frequent soil disturbance. This study, conducted from 2003 to 2005 in an organic vs. conventional rotations experiment in New Brunswick, examined changes in available soil N and in tissue N of snap beans following mechanical weeding events. The experimental design included continuous snap beans, and a fully phased snap beans/fall rye rotation, to which combinations of yearly applied fertility (chemical fertilizer or compost) and weed control (herbicide or mechanical weeding) were applied. Two mechanical weedings were performed each season. Plant available soil N was monitored by 24-hour burials of ion exchange membranes beginning 12 hours after weeding in both mechanically-weeded and herbicide-treated plots. Ions were eluted from the membranes and analysed. Coinciding with membrane removal from the soil, aerial bean plant parts were collected for total tissue N analysis. Availability of soil NH₄⁺-N was not affected by weeding treatment. Soil NO₃^--N availability, however, was consistently less in mechanically weeded plots than in plots treated with herbicide. Weeding method affected tissue N, and interacted significantly with rotation. Scattergrams of treatment means plotted as total tissue N vs available soil N revealed these interactions as distinct groupings. See the Full Presentation (PDF). Also see a Poster from Colloquium of Organic Research (COR) 2006. Edinburgh, Scotland. September 18-20, 2006. Source Oral Presentation. Organic Research Symposium, Guelph, Ontario, January 26, 2007. Author Locations and Affiliations (1) Agriculture and Agri-Food Canada, Senator Hervé J. Michaud Research Farm, P.O. Box 2069, Bouctouche NB E4S 4J1 (2) Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre, 32 Main Street, Kentville NS B4N 1J5 en français Posted October 2007
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Short-term effects of mechanical weeding on soil and tissue N in snap beans grown in an organic vs. conventional rotations

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