Project Overview
Information Products
Commodities
- Agronomic: soybeans
Practices
- Crop Production: cover crops, no-till
- Education and Training: on-farm/ranch research
- Pest Management: integrated pest management
Abstract:
No-till (NT) and cover crops (CC) used in concert improve agricultural sustainability in our region of Southern Wisconsin by increasing crop yield when properly managed, protecting soil while enhancing soil health, protecting water quality by reducing nutrient loss and their use is socially acceptable, giving farmers “license to farm”- overall public approval from keeping the landscape green. However, difficult to control weeds which are glyphosate tolerant or resistant (GTRW) are now prevalent, threatening the combination because alternative management options include tillage or eliminating CC residue to increase residual herbicide efficacy, either of which will negate sustainability gains. We hypothesize that using winter rye as cover and managing its biomass differently than currently practiced will suppress problematic weeds, adding to CC functionality and overall sustainability.
Replicated strip-trials on 4 farms over 2 years evaluated cereal rye cover crop use/ management (planting rate and termination timing) for weed suppression compared to current Extension recommendations for management of GTRW without rye. We monitored weed dynamics throughout the growing season and impact on crop yield. We also examined the impact of rye canopy on efficacy of residual herbicide to determine if spray interception is cause for concern. We found that planting green and terminating rye at anthesis reduced GTRW populations by 94-100% compared to University of Wisconsin Extension best practice recommendations but reduced soybean yield by up to 29%. Terminating rye before soybean emergence reduced populations by 40 to 64% and was yield neutral to positive. We also surmise the practice could be an important component of resistance management to steward the new traits developed in response to resistance to glyphosate. Finally, GTRW suppression was always greater in systems with rye: if rye biomass intercepted residual herbicide reducing its efficacy, the impact was offset by rye’s suppressive effects.
Our outreach activities included a hands-on field day, interactions with highly engaged, regional farmer-led watershed groups, regional and national conference presentations, media articles and direct farmer-consultant communication through one of our projects partner farmers who is also a practicing crop consultant.
Project objectives:
- Determine if rye planting rate and delayed termination i.e. “planting green” are effective for controlling/suppressing problematic GTRW in no-till soybean. Soybean is the crop of interest because this rotational phase is where the problem is greatest
- Compare use of cover crops against current University of Wisconsin-Extension (UWEX) herbicide recommendations for GTRW suppression
- Determine if rye residue from traditional, preplant termination affects efficacy of preemergence residual herbicide
- Determine effect of termination timing on rye aboveground biomass and soybean yields
- Share results and experiences with farmers and technical advisors including UWEX Weed Science.