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The potential for healthy soils to address goals of productivity and sustainability has motivated a global soil health movement. Though this movement involves many groups, farmers’ perceptions are particularly important because they influence whether and how soil health concepts are practiced on farms. We used surveys of Michigan row crop farmers, followed by cognitive mapping exercises and interviews with a smaller subset of farmers, to describe how farmers understand, manage, and evaluate soil health. We report three key findings. First, we found that Michigan farmers believe in the benefits of soil health, but they are less certain of how to manage soil health on-farm. In particular, farmers found it challenging to evaluate how practices alter soil properties they know are important for soil health, including organic matter, compaction, and soil biology. Second, we found that most Michigan farmers are taking steps to improve the health of soils they farm, which was reflected in their current practices. Use of no-till and cover crops was especially prominent, and decisions to utilize them were motivated by yield benefits and water management. Third, we show that farmers primarily assess soil health with traditional agronomic soil tests and qualitative indicators (e.g., yield, crop coloration, and soil texture), which have strong ties to soil type. Overall, our findings emphasize that while Michigan farmers agree on the key properties and outcomes of healthy soils, they are less certain of how their management translates into improved soil health on-farm. Developing faster-responding, outcome-focused indicators as well as local benchmarks guided by soil type may motivate future adoption and retention of soil health practices. 

Abstract The transition from conventional to more regenerative cropping systems can be economically risky due to variable transition period yields and unforeseen costs. We compared yields and economic returns for the first 3 years of the transition from a business as usual (BAU) conventional corn (Zea mays)–soybean (Glycine max) rotation to an aspirational (ASP) five‐crop (corn‐soybean‐winter wheat [Triticum aestivum]–winter canola [Brassica napus]‐forage) rotation in the Upper Midwest United States. Regenerative ASP cropping practices included the more diverse crop rotation, continuous no‐till, cover crops, precision inputs, and livestock (compost) integration. For the first two transition years, BAU corn yields were 8%–12% higher than ASP while in the third transition year, BAU corn yields were 5% lower. Soybean yields were similar for the first 2 years but higher in BAU in the third year due to an ASP pest outbreak. Equivalent yields for other ASP crops were lower than BAU in the first 2 years but similar in the third year except for canola, which suffered from slug damage. Whole‐system economic returns narrowed across years; by year three, whole system comparisons for the ASP corn and soybean entry points (corn‐soybean‐wheat and soybean‐wheat‐canola, respectively) showed equivalent economic returns for BAU and ASP, despite yield differences, owing largely to the ASP system's reduced operational costs. Overall findings suggest that early regenerative systems can be as profitable as conventional systems with careful attention to rotation entry points and inputs. 

Abstract Agricultural researchers are increasingly encouraged to engage with stakeholders to improve the usefulness of their projects, but iterative research on the design and assessment of stakeholder engagement is scarce. The USDA Long‐Term Agroecosystem Research (LTAR) Network recognizes the importance of effective engagement in increasing the utility of information and technologies for future agriculture. Diverse stakeholders and researchers at the Kellogg Biological Station (KBS) LTAR site co‐designed the KBS LTAR Aspirational Cropping System Experiment, a process that provides a testing ground and interdisciplinary collaborations to develop theory‐driven assessment protocols for continuous stakeholder engagement. Informed by prior work, we designed an assessment protocol that aims to measure participant preferences, experiences, and perceived benefits at various stages of this long‐term project. Two online surveys were conducted in 2021 and 2022 among participants of LTAR engagement events at KBS, using a pre‐post design, resulting in 125 total responses. Survey respondents had positive perceptions of the collaboratively designed research experiment. They had a strong expectation that the research would generate conservation and environmental advances while also informing policy and programs. Respondents also indicated a desire to network with other stakeholders. The research team noted the significant role of a long‐term stakeholder engagement specialist in inviting participants from diverse backgrounds and creating an open and engaging experience. Overall, results highlight an interdisciplinary path of intentional and iterative engagement and evaluation to build a program that is adaptive and responsive to stakeholder needs. 

In nitrogen (N)-limited terrestrial ecosystems, plants employ various strategies to acquire and conserve N, including translocation of N in perennial tissues and stimulation of N fixation in roots and soils. Switchgrass (Panicum virgatum) is a genotypically and phenotypically diverse perennial grass with two distinct ecotypes (lowland and upland) and numerous genotypes. It grows well in low-N soils, likely because of its ability to translocate N and to associate with N-fixing microbes, but little is known about variation in these traits among cultivars or even ecotypes. We measured N translocation, N fixation potential in roots and soils, soil net N mineralization, soil net nitrification, and biomass yields in 12 switchgrass cultivars grown in a replicated block experiment in southwestern Michigan, United States. Lowland cultivars had higher yields, rates of N translocation, soil net N mineralization, and N fixation potentials on washed, nonsterile roots, while upland cultivars exhibited higher N fixation potentials in root-free soil. N resorption efficiencies averaged 53 ± 5% (± standard error) for lowland versus 29 ± 3% for upland cultivars. Additionally, there were significant among-cultivar differences for all response variables except mineralization and nitrification, with differences likely explained by cultivar-specific physiologies and microbial communities. The ideal cultivar for biofuels is one that can maintain high yields with minimal fertilizer addition, and there appear to be several cultivars that meet these criteria. In addition, results suggest substantial N cycle differences among cultivars that might be exploited by breeders to create new or improved high-yielding, N-conserving switchgrass lines. 

Microbial communities help plants access nutrients and tolerate stress. Some microbiomes are specific to plant genotypes and, therefore, may contribute to intraspecific differences in plant growth and be a promising target for plant breeding. Switchgrass (Panicum virgatum) is a potential bioenergy crop with broad variation in yields and environmental responses; recent studies suggest that associations with distinct microbiomes may contribute to variation in cultivar yields. We used a common garden experiment to investigate variation in 12 mature switchgrass cultivar soil microbiomes and, furthermore, to examine how root traits and soil conditions influence microbiome structure. We found that average root diameter varied up to 33% among cultivars and that the cultivars also associated with distinct soil microbiomes. Cultivar had a larger effect on the soil bacterial than fungal community but both were strongly influenced by soil properties. Root traits had a weaker effect on microbiome structure but root length contributed to variation in the fungal community. Unlike the soil communities, the root bacterial communities did not group by cultivar, based on a subset of samples. Microbial biomass carbon and nitrogen and the abundance of several dominant bacterial phyla varied between ecotypes but overall the differences in soil microbiomes were greater among cultivars than between ecotypes. Our findings show that there is not one soil microbiome that applies to all switchgrass cultivars, or even to each ecotype. These subtle but significant differences in root traits, microbial biomass, and the abundance of certain soil bacteria could explain differences in cultivar yields and environmental responses. 

Abstract The Kellogg Biological Station Long‐term Agroecosystem Research site (KBS LTAR) joined the national LTAR network in 2015 to represent a northeast portion of the North Central Region, extending across 76,000 km²of southern Michigan and northern Indiana. Regional cropping systems are dominated by corn (Zea mays)–soybean (Glycine max) rotations managed with conventional tillage, industry‐average rates of fertilizer and pesticide inputs uniformly applied, few cover crops, and little animal integration. In 2020, KBS LTAR initiated the Aspirational Cropping System Experiment as part of the LTAR Common Experiment, a co‐production model wherein stakeholders and researchers collaborate to advance transformative change in agriculture. The Aspirational (ASP) cropping system treatment, designed by a team of agronomists, farmers, scientists, and other stakeholders, is a five‐crop rotation of corn, soybean, winter wheat (Triticum aestivum), winter canola (Brassicus napus), and a diverse forage mix. All phases are managed with continuous no‐till, variable rate fertilizer inputs, and integrated pest management to provide benefits related to economic returns, water quality, greenhouse gas mitigation, soil health, biodiversity, and social well‐being. Cover crops follow corn and winter wheat, with fall‐planted crops in the rotation providing winter cover in other years. The experiment is replicated with all rotation phases at both the plot and field scales and with perennial prairie strips in consistently low‐producing areas of ASP fields. The prevailing practice (or Business as usual [BAU]) treatment mirrors regional prevailing practices as revealed by farmer surveys. Stakeholders and researchers evaluate the success of the ASP and BAU systems annually and implement management changes on a 5‐year cycle.