Adaptive Management for Maximizing Soybean Production Following Cereal Rye Termination
Sustainable Production
AgricultureField management
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Shalamar Armstrong, Purdue University
Co-Principal Investigators:
Shaun Casteel, Purdue University
Giovani Preza-Fontes, University of Illinois at Urbana-Champaign
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Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:
Research has shown inconsistencies in soybean yield following a cereal rye cover crop termination. This project is looking at nitrogen and sulfur deficiencies as a result of rye cover crop usage and management strategies to replace these nutrients. The study goals are to understand the paths that advance soybean yield with cereal rye, find the impact of cereal rye nitrogen and sulfur scavenging on soybean yield and quality as well as soybean nutrient usage; and to determine the mechanisms that reduce soybean yield when a cereal rye cover crop is used.
Key Beneficiaries:
#agronomists, #extension crop specialists, #farmers
Unique Keywords:
#cover crops, #nutrients
Information And Results
Project Summary

While the impacts of cereal rye cover crop on corn production have been studied widely, there are still many questions about management practices for soybean following cereal rye. Optimizing soybean production after cereal rye is essential to increase the adoption of cover crops by farmers in IL, a trend that is expected to continue considering the IL nutrient loss reduction goals. Therefore, the overarching goal of the study is to maximize soybean production by advancing cover crop and intense/nutrient management synergies.

Project Objectives

Cereal rye is the most common cover crop utilized in corn-soybean systems, due to its ease of establishment and termination, ability to uptake residual N, winter hardiness, and relatively low seed cost (SARECTIC, 2017). Furthermore, cereal rye has been demonstrated to decrease N losses in tile-drained landscapes (Ruffatti et al., 2019), increase C sequestration (Poeplau and Don, 2015), improve N cycling (Lacey and Armstrong, 2014; 2015), and reduce erosion (Basche et al., 2016). However, while the environmental and soil health benefits of cereal rye are well established, soybean agronomic benefits remain uncertain. Studies in the Midwest region of the U.S. have reported that cereal rye increased (Moore et al., 2014), decreased (Eckert, 1998), and did not affect soybean yield (De Bruin et al, 2005). This uncertainty in the literature for soybean following cereal rye termination demonstrates a level of economic risk for adopting farmers and that more detailed studies are needed to better understand the system and to develop adaptive management plans for more consistent optimization of yield production.

Dominantly in the research literature, soybean yield reduction following cereal rye termination has been linked to planter interference and failed termination that results in stand reduction (Schipanski et al. 2014). However, little focus has been given to the potential of cereal rye growth resulting in deficient soil N and S levels that affect soybean development and nodulation. Dr. Armstrong’s lab has demonstrated that cereal rye has the potential to scavenge >1-118 lbs/A of N from the soil but only 10% of its residue N released during decomposition is recovered by the following soybean plant. Additionally, cereal rye has the potential to scavenge 0.2-6 lb/A of sulfur (S) from the soil (Figure 1A) and because S must be released from the residue similar to N, its return to soil is likely as slow as N release. A preliminary on-farm trial conducted by Dr. Casteel’s lab found that AMS increased soybean yield following cereal rye relative to no AMS application (Figure 1B).

Soybean takes up ~5 lb of N and 0.35 lb of S per bushel, so a 70-bu soybeans would need 350 lb N and 24.5 lb S per acre. Nearly 75% of the N and over 50% of the S are removed in the grain (largely in amino acids of the protein), and thus ~260 lb N and ~13 lb S per acre are removed from the field in the grain. Soybean takes up N in the “easiest” forms possible (e.g., soil N and fertilizer N) followed by biological N fixation (BNF). The direct N uptake from the soil or supplemental N requires less energy than BNF for the soybean plant. Biological N fixation can provide anywhere from 48-93% of a soybean’s N needs, with the United States averaging about 60% (Tamagno et al., 2018). Sulfur is a macro-nutrient that is needed as a co-factor for proper nodulation and fixation by Bradyrhizobium japonicum for soybean. If soil N supply is limited, greater demand is placed on BNF to supply N. Furthermore, if S supply is limited (e.g., limited mineralization, scavenged or leached S, low S deposition), then BNF is compromised and could have cascading effects on soybean growth and development, yield, and quality.

Therefore, the overarching goal of the study is to Maximize soybean production by advancing cover crop and intense/nutrient management synergies (i.e., N and S). Our specific research goals are to (1) Understand the paths that advance soybean yield with cereal rye inclusion (i.e., water holding capacity later in the season, N and S release, etc.); (2) investigate the impact of cereal rye N and S scavenging on soybean nutrient utilization (N and S), seed yield, and seed quality; and (3) determine the mechanisms that impede soybean yield under cereal rye inclusion (i.e., immobilization of N and S, limited microbial activity, delayed soybean development, and nodulation/fixation).

Project Deliverables

This project will be conducted at two sites that are representative of Illinois soybean production (Mollisol and Alfisol). We will investigate the effects of N and S fertilization, implemented alone or in combination, on soybean seed yield and seed quality following a cereal rye cover crop. Each field trial will have eight treatments from a 2×4 factorial design with two cover crop treatments and four fertilizer treatments that will be implemented with field-scale equipment, replicated four times, totaling 32 plots.

Cover crop management:
Cereal rye will be planted after corn harvest using a 7.5-in row no-till drill at a seeding rate of 50-60 lbs/A. Before termination in the spring, aboveground biomass will be sampled to determine cereal rye biomass production and total N, S, and C uptake. Cereal rye biomass will be sampled from two random locations within each plot using a 0.25 m2 quadrat (2.7 ft2 ). Cereal rye will be terminated by spraying glyphosate when the plant is 6 to 12 inches tall, before the “boot” stage (stem elongation) or within 1-2 weeks before soybean planting. Soil samples will be taken before soybean planting at a depth of 0-1 ft to evaluate soil N and S reduction by cereal rye.

Soybean management:
Soybean will be grown following corn in a typical 2-yr corn-soybean rotation in Illinois. Soybean will be planted with 15-in row spacing at 140,000 seeds/A. The S (20 lb S/A) and N (40 lb N/A) fertilizers will be broadcast at or near planting using pelletized gypsum (0-0-0-21Ca-17S) (Trade name: Sul4R-Plus) and urea (46-0-0), respectively. General soil fertility will be determined prior to fertilizer applications. Two composite soil samples will be taken per rep (sampling from cereal rye plots and sampling from no cereal rye plots). One in-season soil sample will be taken within the soybean plots between V4 and R2 (full bloom). Most recent mature leaves will be collected at V4, R2, and R4 (full pod) to provide nutritional (macro- and micronutrient) snapshots across the growing season and correlated with treatments (N and S, in particular). At each sampling event, tissue sampling would consist of collecting 25 trifoliates within each plot. Soybean grain samples will be taken during harvest or with individual R8 whole plant samples prior to harvest. These grain subsamples will be analyzed for all macro- and micronutrients as well as analyzed with NIR for quality (protein and oil) and seed size determination. Field-scale combine will harvest the center of the plots with calibrated yield monitor with GPS tracking.

Communications plan:
Preliminary results from 2023 will be presented at Extension winter workshops, meetings, and conferences of producers, Extension educators, crop professionals across the Midwest and at the Midwest Cover Crop Council annual meeting. We will also write newsletter articles to be disseminated through Extension newsletters and popular press. Other communication partners include Hoosier Ag Today with our Purdue Crop Chat. Conclusions from the experiments in 2023- 2024 will be shared at the American Society of Agronomy meetings and other professional meetings like North-Central Soil Fertility.

Progress Of Work

Final Project Results

Benefit To Soybean Farmers

We aim to determine the situations that could impede soybean development and yield following cereal rye and develop adaptive management to mitigate N and S deficiencies. Thus, we could also provide an underpinning for management strategies to maintain or improve soybean yield and quality when coupled with cereal rye.

Growers, agronomists, and soybean physiologists will be the beneficiaries of this research. We aim to determine the situations that could impede soybean development and yield following cereal rye and develop adaptive management to mitigate N and S deficiencies. Thus, we could also provide an underpinning for management strategies to maintain or improve soybean yield and quality when coupled with cereal rye.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.