The Kellogg Biological Station is a patchwork of experimental agricultural plots. Here, a poplar crop stands behind an unplanted plot. Credit: Gabriel De La Rosa, CC BY-SA 4.0.

An aerial view of the midwest reveals a landscape partitioned into various shades of green. The ecology of this region is dominated by agriculture. Cropland determines all sorts of ecological function, from nutrient flows through a landscape to animal movement across agricultural plots. In 1987, the National Science Foundation funded the Kellogg Biological Station (KBS) Long-Term Ecological Research (LTER) site to study how different agricultural practices determine how an ecosystem functions. 

Now, the LTER site is just one piece of a thriving long-term research program at the Kellogg Biological Station. In 2008, the Great Lakes Bioenergy Research Center (GLBRC) initiated long-term plots adjacent to the Kellogg Biological Station LTER plots to dive deep into plant based energy production. In 2020, the Long-Term Agroecosystem Research (LTAR) Network established another experimental area at the Kellogg Biological Station to study how innovative agricultural practices affect crop productivity in the midwest. 

These partnerships form the center of long-term research at the Kellogg Biological Station, and while their goals are different, their work is deeply intertwined. Here, we explore each initiative in detail, showing how the projects bring a unique perspective to agricultural research but also draw on the others to maximize their potential.

The Kellogg Biological Station LTER: How does agriculture affect the ecosystem?

  • Funder: National Science Foundation
  • Main experiment: Main Cropping System Experiment (MCSE)
    One-hectare plots managed in eleven different ways
  • Goal: Understand how agricultural practices affect ecosystems over long timescales

Central to the Kellogg Biological Station’s LTER research are a series of one-hectare agricultural plots planted and managed in different ways. The Main Cropping System Experiment contains eleven distinct crop rotations, each repeated five or so times. Several plots are variations on a corn-soybean-wheat rotation, each varying in management practice, such as whether they are tilled or have a cover crop rotation. Other experimental plots are monoculture for switchgrass or poplar, promising bioenergy crops. The remaining plots are crucial for comparing active agriculture to other processes; two are in the surrounding forestland, one is a formerly agricultural plot left to recover since 1990, and the last is a grassland plot that has never been planted or tilled.

How LTER researchers use the MCSE

These plots provide a powerful way to compare the effects of different agricultural practices on ecosystem processes. For example, the longest dataset at the LTER is a sediment core dataset for each plot. KBS researchers used this dataset to show that cutting down forest to make space for agricultural plots resulted in the release of about a third of the original soil carbon over time. Furthermore, even the best agricultural practices only return a marginal amount of soil carbon to those plots. The LTER conducts studies such as this to show how agricultural practice affects the ecosystem, from insects to nutrients to soils and beyond.

LTER surveys tie research to the community

Key to this research is an understanding of what farmers are actually doing in the region. So, alongside the long-term experiments, the LTER conducts a Farmer Survey of landowners across the midwest. From this, researchers glean which agricultural practices are most common, but also where farmers might like to see change, how farmers think about a changing climate, and more.

Rainfall exclusion shelters at the KBS LTER. The experimental plot design also allows for smaller experiments within fields, such as these shelters designed to keep rainfall out of small sections of cropland. Credit: Gabriel De La Rosa, CC BY-SA 4.0.

The Kellogg Biological Station LTAR: What should agriculture look like in 30 years?

  • Funder: United States Department of Agriculture
  • Main experiment: 300 acre plots, planted with the best management practices
  • Goal: explore the most promising avenues for crop production

Where the LTER is reactive—see what farmers are doing, study the effects—the LTAR is built on proactive co-production with farmers and other agricultural stakeholders. Core to the LTAR is their Aspirational Cropping System experiment, where 300 acre plots are planted using all of agriculture’s best tools to grow food. Four different treatments run at any given time, all with the potential to outperform traditional agriculture.

One key difference with the LTER plots is that the LTAR treatments are adaptive: as new ideas or technology emerge in the agricultural space, the experiments can change to incorporate them. Notably, these changes are stakeholder driven. 

Fields of flowering Canola at the KBS LTAR site. Many of the experimental crop rotations include Canola, plus Corn, Soy, and Wheat in rotation. Credit: Gabriel De La Rosa, CC BY-SA 4.0.

LTAR research can incorporate stakeholder feedback

For example, several fields now incorporate Prairie Strips, an idea pioneered at Iowa State University to plant strips of native prairie in the middle of agricultural fields to provide pollinator habitat and enhance hydrology and soil function in fields. KBS stakeholders wanted to know if prairie strips in Michigan would have similar environmental benefits to those implemented in Iowa. 

Implementation is an important part of the LTAR

Both the LTER and the LTAR added prairie strips to their fields several years ago. The LTER asked questions about if prairie strips could bring ecological benefits to cropland in Michigan, and found that everything from pollinator abundance to soil health increased with the strips. 

The LTAR takes these benefits one step further, asking whether prairie strips are sustainable and, ultimately, profitable for farmers. They found that strips planted in historically low-yielding areas of fields did not reduce crop yields but still provided environmental benefits. The LTAR also hosted outreach events such as Prairie Strip Field Days and joint meetings with scientists and stakeholders to encourage farmers to implement prairie strips on their own land.

Great Lakes Bioenergy Research Center: How can we grow crops for biofuel in an ecologically and economically sustainable way? 

  • Funder: Department of Energy
  • Main Experiment: Ten experimental plots of bioenergy crops planted across a range of species diversity
  • Goal: Understand how bioenergy production can work at scale
Switchgrass fields are part of the GLBRC research plots, and key for exploring the environmental benefits of this promising new crop. Credit: Gabriel De La Rosa, CC BY-SA 4.0.

In 2008, the Great Lakes Bioenergy Research Center (GLBRC) initiated work at the Kellogg Biological Station to compare different crops planted for bioenergy. The project is the largest discovery based grant at Michigan State University, and the LTER was a key consideration when the project selected KBS as their home base.

The scope of the GLBRC’s vision is massive. There are 100 million acres of agriculture in the upper midwest Corn Belt. A significant portion of the corn grown in the region is dedicated to bioenergy production. Yet corn carries significant environmental detriment. 

The KBS LTER has a deep mechanistic understanding of how this ecosystem functions, beginning with understanding the environmental harms of corn production and continuing to study how alternative bioenergy crops affect the function of the ecosystem. The GLBRC builds on the LTER research by exploring how these bioenergy crops might work at scale. Can a transition to bioenergy provide ecosystem benefits?

The main experiment at the GLBRC contains ten experimental plots of bioenergy crops across a range of diversity, from monoculture to very diverse grassland, and sample collection explores how ecosystem services vary across this gradient. 

Towards better bioenergy production: Can a monoculture mimic a diverse plot?

One of the most promising and exciting results of the experiment is the environmental benefits of switchgrass monoculture. A newer bioenergy crop candidate, switchgrass fields provide similar pollinator, carbon storage, and soil benefits compared to more diverse crop blends. Plus, switchgrass can grow in poor soils, greatly expanding yields in otherwise difficult locations. With so many environmental benefits, the GLBRC is now actively investigating how to make switchgrass monoculture profitable at large scales.

By Gabriel De La Rosa

Thank you to everyone at the Kellogg Biological Station for hosting our 2023 LTER Science Council Meeting, especially Nick Haddad, Nameer Baker, and Liz Schultheis.