Why It Exists
The Morrow Plots, established in 1876, are the world's second-oldest continuous crop research site (behind one in England established in 1843 for continuous wheat), and the world’s oldest crop rotation experiment (and corn for that matter). They've already answered the big questions of their era that proves synthetic fertilizer and improved genetics could push corn yields well past the 25-35 bu/acre farmers got with no inputs back in the 1800s through the 1920s.
But researchers say the Morrow Plots have done what they set out to do. The Alma Mater Plots are meant to pick up where they left off, tackling questions relevant to today's farming: water quality, carbon intensity (CI), nitrogen use efficiency, soil health, and – above all – profitability.
The Tile Drainage Angle
This is the part that sets the site apart. Every third tile line is individually monitored, with buffer tiles on either side to isolate what each treatment is doing to the monitored tile. This lets researchers understand management impacts on tile flow and nutrient discharge, providing insights to water and nutrient loss outcomes in real time.
What's Growing There Now
For the first three years (through 2026), the plots are running a Foundation for Food and Agriculture Research (FFAR) study testing a newly agreed-upon national protocol for evaluating enhanced-efficiency fertilizer products (Lyons et al., 2025). This yield and nitrogen use efficiency data is intended to help farmers sort real label claims from marketing. Additionally, the results of how nitrogen rates correspond to tile nitrate-N losses, and the effect of split application and inhibitors, will help inform the Illinois Nutrient Loss Reduction Strategy (NLRS) list of proposed conservation practices.
After that, the site moves into its long-term phase and that's where farmer input comes in.
"What will the next 150 years bring? We're at that halfway mark, from 1876 to 2178," Margenot said. "What needs to happen in the design of this long-term study? This is the Morrow Plots for the 21st century and into the 22nd century."
Farmers Are Shaping the Research
Rather than deciding the long-term treatments in an office on campus, the research team has spent the past year running focus groups across the state (more than a dozen so far, with over 140 farmers and dozens of industry stakeholders weighing in) to figure out what should actually be tested for the next 150 years.
Themes coming out of those conversations so far:
- Conservation practices - cover crops, reduced herbicide and fertilizer inputs
- Water quality and nitrate loss from tile-drained ground
- Soil health trade-offs across different rotations and inputs
- Profitability - not just yield, but what pencils out for net ROI
A Few Interesting Finds from Morrow Plots
Researchers are pulling insights from soil samples archived since 1904 at the Morrow Plots:
- Illinois soils have lost about half their original organic matter since prairie was first broken and roughly half of what remains today is still "legacy" organic matter from the original prairie with some of it dated to around 2,500 years old.
- Phosphorus applied in the plots' earliest years (much of it from rock phosphate and steamed (bison) bone meal is still detectable in the soil more than 120 years later. This is the first documented case of "legacy phosphorus" persisting that long anywhere in the world, with implications for fertility but also water quality.
