Research HighlightsCereal Rye Cover Crop Termination Timing Effects on Soybean Yield Across the Midwest
In this article, you’ll find details on:
- Effect of cereal rye termination timing on soybean yield: Terminating cereal rye at or before soybean planting had minimal impact on soybean seed yield.
- Impact of cereal rye biomass on soybean yield: No association was observed between rye biomass accumulation and soybean yield.
- Benefits of cereal rye as a cover crop: Farmers across the examined region can consider adopting cereal rye as a winter cover crop. While cereal rye offers long-term benefits for soil conservation and ecosystem services, it’s important to consider the associated costs. Project results show no short-term soybean yield benefits that would offset these costs.
- Future research directions funded by checkoff dollars: Ongoing studies in Wisconsin are investigating how cereal rye management and termination timings affect soybean seed yield, aiming to better understand and optimize this system.
By Tatiane Severo Silva, Spyridon Mourtzinis, Anthony Justin McMechan (UNL), Gabriela Inveninato Carmona (UNL), Bruce D. Potter (UMN), Kelley J. Tilmon (OSU), Louis S. Hesler (NCARL), Nicholas J. Seiter (UIUC), Robert Wright (UNL), Shannon L. Osborne (NCARL), Thomas E. Hunt (UNL), Shawn P. Conley. Reprinted with permission.
Choosing the right time to terminate cereal rye cover crops is crucial for maximizing their benefits in corn–soybean rotations. Research suggests that terminating cereal rye too early can diminish its weed suppression5and soil conservation benefits, while delaying termination might affect cash crop establishment2. In general, unfavorable fall–winter weather conditions in the Midwest restrict cover crop establishment and growth. Ideally, cereal rye termination should occur when enough biomass has accumulated to provide greater benefits in terms of reduced soil erosion, weed suppression and improved soil health. Factors such as weather conditions and equipment availability play a role in this decision.
By coordinating termination with planting schedule and considering local weather patterns, cereal rye’s contributions to soil health and cash crop productivity can be optimized. To help farmers decide between early termination or termination at planting based on soybean seed yield impacts, this study1 was conducted in 28 location-years in the Midwest region to assess the effect of cereal rye termination timings (termination before and at soybean planting) on soybean yield in corn-soybean systems.
Field Experiments
Field experiments were conducted across 28 location-years in Illinois, Nebraska, Ohio, South Dakota and Wisconsin (USA) from 2019-2021 (Figure 1). Our goal was to assess the effects of two cereal rye cover crop termination timings on soybean seed yield. These experiments were part of a corn-soybean rotation managed under no-till conditions, with corn planted in the previous growing season at all study sites.
Across location-years, soybean varieties used ranged from 0-3 in maturity group (MG), planted in 30-inch rows between early May to mid-June, guided by regional soybean planting recommendations and local weather conditions.
The cereal rye cover crop was drilled in corn stubble using a no-till grain drill at a seeding depth of ~1-in, with seeding rates adjusted according to local extension recommendations. Our treatments included:
- No cereal rye (T1)
- Cereal rye terminated before soybean planting (T2)
- Termination at soybean planting (T3).
The interval of cereal rye termination dates varied across location-years (Table 2). Cereal rye variety, planting rate, planting date, and termination dates in each experimental location-year are presented in Tables 1 and 2. Glyphosate (Roundup PowerMAX at 32 fluid ounces/acre) was used for chemical termination of the cereal rye cover crop at each timing.
Impact Of Cereal Rye Termination Timings On Cereal Rye Biomass
The average treatment effect of termination timings across all location-years was significant for cereal rye biomass accumulation (P < 0.001; Figure 2). The average cereal rye biomass was 203 pounds/acre when terminated before planting and 626 pounds/acre when terminated at planting. Generally, cereal rye biomass accumulation was low across location-years, with 13 of 28 location-years producing less than 890 pounds/acre of biomass (Figure 2). The low cereal rye cover crop biomass accumulation across location-years is likely due to late planting dates (Table 2) after corn grain harvest and poor fall establishment. NE-Hall-2019 produced the highest cereal rye biomass for termination before soybean planting (1,695 pounds/acre), and MN-Lamberton-2021 produced the highest biomass (3,803 pounds/acre) for termination at soybean planting.
Impact Of Cereal Rye Termination Timings On Soybean Yield
The average treatment effect of termination timings across all location-years on soybean seed yield was not significant (P = 0.542). Termination timings did not affect soybean seed yield in 25 of 28 location-years (Figure 3). Similarly, in a study conducted in Wisconsin3, terminating cereal rye 14 days before planting and at planting did not have any significant impact on soybean seed yield. In contrast, a study in Nebraska found that soybean seed yield was affected by cover crops in 3 of 12 location-years when compared to no cover crop treatment4. However, according to the authors, the reduction in yield was not associated with cover crop biomass but likely due to dry weather conditions and high weed pressure.
In 2019 at OH-Wooster, low soybean seed yield was due to poor establishment from early-season cold and flooding. Cereal rye cover crop terminated at planting might help with water uptake and infiltration, which probably alleviated the flooding, consequently improving soybean establishment and leading to a higher yield compared to the no cover crop treatment. In OH-Wooster-2021, the high soybean yield observed for the cover crop treatments compared to no cover crop might be due to the high biomass produced by the cover crop, which likely conserved soil moisture during the growing season.
References
1Cereal rye cover crop termination at or before soybean planting has minimal effect on soybean yield across the midwestern US. Tatiane Severo Silva, et al. (2024). Field Crops Research, 312, 109393. May 2024
2Agronomic and economic tradeoffs between alternative cover crop and organic soybean sequences. Rebecca J. Champagne, et al. Renewable Agriculture and Food Systems, 36(1), 17-25. February 2021
3Cereal rye cover crop terminated at crop planting reduces early‐season weed density and biomass in Wisconsin corn–soybean production. Kolby R. Grint, et al. Agrosystems, Geosciences & Environment, 5(1), e20245. February 2022
4Cover crop productivity and subsequent soybean yield in the western Corn Belt. Katja Koehler‐Cole, et al. Agronomy Journal, 112(4), 2649-2663. April 2020
5Cover crops and weed suppression in the US Midwest: A meta‐analysis and modeling study. Virginia Nichols, et al. Agricultural & Environmental Letters, 5(1), e20022. June 2020
Published: Dec 30, 2024
The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.
