Exploring the Effects of Prairie Restoration Management on Soil Microbial Carbon Storage

View the project final report

Commodities

• Additional Plants: native plants

Practices

• Natural Resources/Environment: carbon sequestration
• Soil Management: organic matter, soil microbiology

Exploring the Effects of Prairie Restoration Management on Soil Microbial Carbon Storage

Integrating restored prairies into agricultural landscapes has emerged as a strategy for providing key ecosystem services like increasing biodiversity, reducing erosion and runoff, and supporting pollinator communities. These prairies can also act as valuable soil carbon sinks, though they often fall short of their carbon storage potential. This study aims to help farmers maximize carbon storage on their land by examining the influence of prairie management choices on soil microbial carbon dynamics, asking how prairie seed mix richness influences soil microbial carbon use efficiency and what this means for total soil carbon stores. Increasing soil carbon in agricultural systems has the potential to restore soil carbon stores lost through the transition to cropland and to offset ongoing agricultural greenhouse gas emissions. This work is particularly relevant with the Conservation Reserve Program’s recent addition of extra incentives for Climate-Smart Practices, including increasing carbon sequestration. By filling a key knowledge gap in managing for maximized soil carbon storage, this work can inform climate change mitigation efforts and thus contribute to increased environmental quality and quality of life in agricultural systems and beyond.

We sampled soils from a series of row crop agricultural fields planted to corn, oldfields abandoned from agriculture, prairies seeded with a low-richness seed mix of twelve plant species, and prairies seeded with a high-richness seed mix of seventy plant species. We compared carbon and microbial metrics across these soils to see how these different land management strategies affected soil carbon pools and microbial carbon use efficiency. We partnered with MiSTRIPS, the Kellogg Biological Station, Michigan State University Extension, the Osher Lifelong Learning Institute, and Western Michigan University to reach local stakeholders in 2023 and 2024. Informed by our research, we presented the results of our work to these groups and created a decision-making tool to share with managers. We will continue to disseminate our results by submitting articles to academic and farmer-focused publications and presenting at local and national scientific conferences.

We found that agricultural soils consistently had the lowest soil carbon stores, but the oldfields and both types of prairie were comparable to each other. Similarly, agricultural soils had the lowest microbial biomass and activity (as measured by respiration), while old fields and prairies were again similar. This indicates that taking land out of production and re-introducing perennial plants to the landscape has positive effects on soil carbon, regardless of whether land is managed as prairie or has a higher richness seed mix. Interestingly, when respiration was standardized to the amount of microbial biomass present, agricultural soils had significantly higher carbon respired per microbial biomass carbon, indicating that, while there were fewer microbes present in agricultural soils, the ones that were there were releasing carbon to the atmosphere at a higher rate, perhaps contributing to the lower carbon stores in agricultural soils.

We discussed our research at outreach events at the Kellogg Biological Station, created and distributed a decision aid pamphlet for blueberry farmers at a Michigan State Extension event, and reached the wider community through running courses with the Osher Lifelong Learning Institute and as part of Western Michigan University's Spring Into Action series. We were successful in distributing our materials about the benefits of prairies in agroecosystems, including distributing prairie seed to interested Osher Lifelong Learning Institute and Spring Into Action attendees who went on to plant backyard prairies.

Research Objectives: Compare soil carbon pools and soil microbial metrics across different land management types to determine how taking land out of active production (oldfield treatment) and converting formerly agricultural land to prairie (prairie treatments) affects soil carbon storage. Furthermore, we wanted to explore how the seed mix richness of the prairie restoration affected soil carbon storage, comparing low (12 species) and high (70 species) seed mix treatments. Through this work, we aim to provide farmers with actionable information about the level of management and financial investment needed to meet soil carbon storage goals.

Outreach Objectives: Leverage partnerships with Michigan State University Extension, MiSTRIPS, Kellogg Biological Station, Western Michigan University, and the Osher Lifelong Learning Institute to network with with local stakeholders and initiate two-way conversations about prairie establishment on Michigan farms, focusing on landowner needs and barriers they anticipate facing in these efforts. Then, informed by these conversations, present the results of our project and distribute our educational products to the groups.