Weed Management Studies - Organic Bread Wheat Production System Trial at Fred Sherburne’s
Lauren Kolb, Tom Molloy, and Ellen Mallory
University of Maine Department of Plant, Soil and Environmental Sciences and Cooperative Extension
We collaborated with Fred Sherburne of Sherburne Farms in Dexter to test two innovative weed management systems for organic spring grains against Fred’s standard practice. These were: (1) narrow row spacing and increased seeding rate to enhance crop competition with weeds, and (2) wide-row spacing with inter-row hoeing using a specially-designed, manually-guided cultivator imported from Germany. The systems were compared for their effects on weed growth, grain yield, and grain quality.
The experiment was planted with Glenn wheat on May 14, 2009 using a Vicon air seeder to seed both the narrow row (4.5”) and the wide row (9”) treatments. Fred used his own grain drill (7” row spacing) to plant the treatment representing his best management practice. Approximate seeding rates for each of the treatments were: wide (130 lbs acre-1), narrow (190 lbs acre -1), and Fred’s (160 lbs acre-1). All treatments received two post-emergence cultivations with a Kovar tine weeder. The wide row treatment was hoed once on June 4 using a Schmotzer inter-row cultivator.
Results: Wheat yields were low this growing season, the result of poor growing conditions and intense weed pressure, mostly from wild mustard. There were no significant differences in grain yield between treatments; however, the narrow row and wide row system had significantly less weed dry matter as a percentage of total dry matter production than Fred’s system.
|Treatment||Grain yield (tons/acre)*||Weeds as a % of total dry matter*|
|Fred’s||0.54 a||36% a|
|Narrow Row||0.63 a||24% b|
|Wide Row||0.67 a||21% b|
* Values followed by the same letter within a column are not statistically different.
Relationship between weed biomass measured at peak, July 10, 2009, and wheat yield at harvest, August 26, 2009. Regression equation: Yield (t acre-1)=0.7609301- 0.0023079* weed biomass (g m-2).
Grain samples are awaiting analysis for percent protein (a key quality measure for bread wheat).
For more information, contact:
Sustainable Agriculture Specialist
University of Maine Cooperative Extension
Funding provided by the Northeast SARE Professional Development Program