Agronomic benefits of alfalfa mulch applied to organically managed spring wheat

M. J. Wiens¹, M. H. Entz¹, R. C. Martin² and A. M. Hammermeister²

Abstract
Field experiments were established at two locations in Manitoba in 2002 and 2003 to determine N contribution, moisture conservation, and weed suppression by alfalfa mulch applied to spring wheat (Triticum aestivum L).

Mulch treatments included mulch rate (amount harvested from an area 0.5x, 1x and 2x the wheat plot area), and mulch application timing (at wheat emergence or at three-leaf stage).

Positive relationships were observed between mulch rate and wheat N uptake, grain yield, and grain protein concentration. At Winnipeg, the 2x mulch rates (3.9 to 5.2 t ha^-1) produced grain yields equivalent to where 20 and 60 kg ha^-1 of ammonium nitrate-N was applied in 2002 and 2003, respectively. Where mulch and ammonium nitrate produced equivalent grain yield, grain protein in mulch treatments was often higher than where chemical fertilizer was used. N uptake was also observed in the following oat (Avena sativa L.) crop.

The highest mulch rate (2x) produced higher N uptake and grain yield of second-year oat compared with ammonium nitrate treatments. N use efficiency of mulch-supplied N by two crops over 2 yr [calculated as (treatment N uptake - control N uptake)/total N added] was between 11 and 68%.

Mulch usually suppressed annual weeds, with greater suppression with late- than early-applied mulch. Increased soil moisture conservation was observed with high mulch rates (= 4.3 t ha^-1) at three sites. Alfalfa mulch holds promise for low-input cropping systems when used on wheat at the 2x rates.

See a Farmer's Independent Weekly news article covering more details of this research

Source
Canadian Journal of Plant Science (2006) 86: 121-131

Author Locations and Affiliations
(1) Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2
(2) Organic Agriculture Centre of Canada, Nova Scotia Agricultural College, P.O. Box 550, Truro, Nova Scotia, Canada B2N 5E3

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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	Agronomic benefits of alfalfa mulch applied to organically managed spring wheat M. J. Wiens¹, M. H. Entz¹, R. C. Martin² and A. M. Hammermeister² *Abstract* Field experiments were established at two locations in Manitoba in 2002 and 2003 to determine N contribution, moisture conservation, and weed suppression by alfalfa mulch applied to spring wheat (Triticum aestivum L). Mulch treatments included mulch rate (amount harvested from an area 0.5x, 1x and 2x the wheat plot area), and mulch application timing (at wheat emergence or at three-leaf stage). Positive relationships were observed between mulch rate and wheat N uptake, grain yield, and grain protein concentration. At Winnipeg, the 2x mulch rates (3.9 to 5.2 t ha^-1) produced grain yields equivalent to where 20 and 60 kg ha^-1 of ammonium nitrate-N was applied in 2002 and 2003, respectively. Where mulch and ammonium nitrate produced equivalent grain yield, grain protein in mulch treatments was often higher than where chemical fertilizer was used. N uptake was also observed in the following oat (Avena sativa L.) crop. The highest mulch rate (2x) produced higher N uptake and grain yield of second-year oat compared with ammonium nitrate treatments. N use efficiency of mulch-supplied N by two crops over 2 yr [calculated as (treatment N uptake - control N uptake)/total N added] was between 11 and 68%. Mulch usually suppressed annual weeds, with greater suppression with late- than early-applied mulch. Increased soil moisture conservation was observed with high mulch rates (= 4.3 t ha^-1) at three sites. Alfalfa mulch holds promise for low-input cropping systems when used on wheat at the 2x rates. See a Farmer's Independent Weekly news article covering more details of this research Source Canadian Journal of Plant Science (2006) 86: 121-131 Author Locations and Affiliations (1) Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2 (2) Organic Agriculture Centre of Canada, Nova Scotia Agricultural College, P.O. Box 550, Truro, Nova Scotia, Canada B2N 5E3 *en français*
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Agronomic benefits of alfalfa mulch applied to organically managed spring wheat

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