Project Overview
Weed management remains a top challenge for organic producers, and frequent tillage and cultivation are typically used to control weeds. However, there is increasing interest in methods that reduce soil disturbance to build soil health. One such method is using cover crops as a living mulch between cash crop rows during the growing season. Cereal rye (Secale cereale L.) has potential as a living mulch in soybeans because it has vigorous early season growth, dying back as the cash crop canopy matures. This study, conducted over two years on certified-organic land in Wisconsin, examined a cereal rye living mulch treatment compared to a standard tillage-based treatment in organic soybean and the resulting effects on rye mulch biomass, weed density and biomass, and soybean yield.
Farmer Takeaways
- Consistent with past research, using winter rye as a living mulch showed neutral to negative impacts on soybean yields compared to traditional tillage-based soybean systems.
- Under optimal conditions, growers can maximize rye living mulch biomass production, which reduces weed pressure. In dry conditions, rye living mulch is reduced, leading to greater weed pressure and lower soybean yield.
- Rye living mulch may suppress broadleaf weeds better than grass weeds, which can influence weed management decisions based on a given location’s weed seedbank composition.
Project Objectives and Approach
Determine potential benefits and risks from (1) interseeding cereal rye with soybeans and (2) delaying soybean planting date in the spring-seeded cereal rye treatment on weed prevalence and soybean production.
- A two-year field trial was established on certified-organic land at the Arlington Agricultural Research Station, with a third-site year established at the Michael Fields Agricultural Institute.
- At all sites, a randomized complete block design was used, replicated four times. Treatments consisted of:
- June planted soybean with interseeded cereal rye living mulch (“June Rye + Soy”)
- May planted soybean with standard tillage (“May Control”)
- June planted soybean with standard tillage (“June Control”)
- The standard tillage treatments utilized in-season tine weeding and inter-row cultivation with a rotary hoe. Additionally, the June Control treatment used stale seedbed preparation with a field cultivator to further manage the weed seedbank prior to delayed soybean planting.
- A May-planted living mulch treatment was not used in the trial based on previous research which found that early rye seeding increased risk of rye vernalization and less time to manage the weed seedbank prior to planting.
- In the June Rye + Soy treatment, rye was interseeded immediately after soybean planting using a no-till drill.
- In August of each year, rye biomass and weed biomass samples were collected, as well as weed density. Soybeans were harvested in November for all treatments.
Key Findings
A living mulch system may produce lower soybean yields than in a tilled system
- Soybean grain yields were smaller in the rye living mulch treatment than in the tilled control treatments.
- Weed density in the June Rye + Soy treatment was higher compared to the two tilled controls.
Maximizing living rye biomass is essential to controlling weeds and achieving high grain yields in this system
- Soybean grain yields in the rye living mulch treatment were higher when rye biomass was higher.
- Higher rye biomass also resulted in greater weed suppression.
- The living rye mulch suppressed broadleaf weeds better than grass weeds, which may have been due in part to broadleaf weed sensitivity to allelopathic compounds such as those found in cereal rye.
Resources
Brockmueller, B., Tautges, N., Vereecke, L., & Silva, E. (2022). Spring-seeded winter rye living mulches enhance crop biodiversity and promote reduced tillage organic soybeans. Frontiers in Sustainable Food Systems, 6, 926606.
Read MoreLocation
WisconsinCollaborators
Nicole Tautges, Michael Fields Agricultural Institute
Léa Vereecke, University of Wisconsin
Erin Silva, University of Wisconsin
Region
Midwest
Topic
Soil Health, Crop Nutrient Management, Weed Management
Category
Grain and Field Crops
Year Published
2022
