The University of Illinois Urbana-Champaign’s Morrow Plots — the oldest continuously running agricultural experiment in North America — celebrate their 150th anniversary this year. It’s a milestone for the College of Agricultural, Consumer and Environmental Sciences, symbolizing its commitment to the land-grant mission, effort to feed a global population, and goal of nourishing its own campus community.
To commemorate the occasion, a new 30-minute documentary highlights the U. of I.’s rich history of agricultural innovation and discovery. “Rooted in Discovery: Agriculture at Illinois” premieres at noon Wednesday, July 8, on the Big Ten Network as part of the network’s Illinois Day.
Stories in the documentary include:
Morrow Plots
To recognize its 150th anniversary, this segment explores the lasting impact of the Morrow Plots. Established in 1876, it is not only the oldest continuous experimental crop field in North America but the second-oldest in the world. Located in the heart of campus, this former patch of prairie has been cultivated year after year, generating invaluable data on soil health and agricultural sustainability that continues to inform researchers around the globe through a freely available dataset.
“Many parts of the world share a similar environment as the ‘Corn Belt of Illinois,’ and these regions stand to benefit from our communication. I’d argue that that goes both ways,” says Andrew Margenot, a professor in the Department of Crop Sciences and the director of the Morrow Plots.
The RIPE Project
By 2050, the world’s growing population is expected to require 50-70% more food production to meet global demand. Realizing Increased Photosynthetic Efficiency (RIPE) at the U. of I. is tackling this challenge by leading an international research effort aimed at improving photosynthesis, the natural process plants use to convert sunlight into energy. From gene editing to canopy architecture, RIPE researchers hope to increase yields and help build a more sustainable food future, especially in countries in sub-Saharan Africa and Southeast Asia.
“While our focus is certainly on smallholder farms, we’re also making changes that we hope will benefit growers everywhere,” says Lisa Ainsworth, the director of RIPE and a professor in the Departments of Crop Sciences and Plant Biology. In addition to addressing food insecurity, the team is also developing solutions to help crops withstand the challenges of a changing climate.
Sustainable Student Farm
Founded in 2009, the Sustainable Student Farm is a unique 5-acre, student-run educational farm that grows a wide array of fruits, vegetables, herbs and flowers. Through low-input, environmentally sustainable growing practices, the farm provides students with hands-on experience in horticulture while teaching valuable skills in food safety, farm operations, infrastructure management and marketing, among many other aspects of sustainable food production. On Thursdays, a stroll across Illinois’ Main Quad will likely lead you to the farm’s stand — one of campus’s most popular destinations for fresh, seasonal produce.
“It really completes the full cycle of having grown this food from seed sometimes and getting to see who’s going to be eating that food,” says Matt Turino, the Sustainable Student Farm manager. About half of what is grown on the farm makes its way into Illinois dining halls, including 12,000 to 18,000 pounds of tomatoes each year, which are transformed into homemade pizza sauce.
“Rooted in Discovery” was produced by Kaitlin Southworth for the University of Illinois Urbana-Champaign’s Strategic Communications and Marketing.
America’s oldest test plots prepare for their next chapter.
Story and Photos by Katie Knapp
“No sir we don’t mess around, our library’s underground. ‘Cause you can’t throw shade on the corn.”
These words finish the chorus of the University of Illinois a cappella group The Other Guys’ famous song about a corn field in the center of campus.
It’s no ordinary corn field next to no ordinary library building.
Legend has it that the library was built underground in the 1960s to not shade out the field. University documents suggest it was for aesthetics, but mission accomplished either way.
The design has preserved the most important one-acre corn field in the western hemisphere.
The Morrow Plots were started 150 years ago as a five-acre research field near the agricultural buildings. The section remaining today has one plot with corn grown continuously each year since then, another in a corn/soybean rotation, and a third in a small grains/soybean/corn rotation.
The Morrow Plots’ longevity is second only to that at Rothamsted Research in England where winter wheat has been studied consistently since 1843.
”If I could go back and talk to the researchers who started the Morrow Plots in 1876, I’d first thank them,” says Crop Sciences Department Head Dr. Adam Davis. ”They were asking decadal questions, questions fundamental to crop production in Illinois.”
”One of the big lessons from the Morrow Plots is that you have to take care of your soil. If you mine your soil, you end up with corn cobs about that big,” he says picking up an ear from last year’s harvest dwarfed by his hand and with only a few yellow kernels. ”If you feed your soil, you can end up with really good yields and sustainable crop production.”
Presumably this was the original hypothesis.
On the original agriculture building dedicated in 1901, just steps from the field, the words of then University President Andrew Sloan Draper are etched along the entrance: ”The wealth of Illinois is in her soil and her strength lies in its intelligent development.”
Davis calls the field a living monument. And the University is rightfully celebrating it, now protected as a National Historic Landmark, this fall.
First thing’s first, though. They must take care of a squirrel problem.
Graham’s visit comes at a defining moment for the college. As ACES marks the 150th anniversary of the Morrow Plots — the oldest continuous crop experiment in the Americas — Bayer’s Crop Science division is supporting their revitalization through a transformative gift. The investment underscores the enduring value of long-term agricultural research and the land-grant mission that continues to drive discovery from Illinois to fields around the world.
For Graham, the connection is both strategic and deeply personal.
Born in Australia, he moved with his family to India at age seven. After one year, they moved again, this time to Colombia. By the time Graham was 18, his family had migrated once more — now to the U.S.
That journey ultimately led him to the College of ACES, where he completed his doctorate in 1993.
Growing up, he witnessed his father’s career as a soil microbiologist, an influence that would shape his own interest in plant breeding and genetics.
“My dad had a passion to think about soil microbiology through the lens of how it benefits smaller farmers. My brother and I would sometimes be among his laborers who helped him with his research. We got a unique vantage point in understanding how science could bring value to a farmer, and that helped us get into crop science and agriculture,” Graham said.
After moving to the U.S., Graham first attended the University of Minnesota, where he earned his bachelor’s degree, and then pursued a master’s degree at the University of Delaware.
“After my master’s, I had experience in corn but was looking to gain experience in soybeans. The question was, where is one of the best places in the U.S. to get that experience? And the answer was the University of Illinois Urbana-Champaign. The university has some of the best knowledge in quantitative genetics across crops and also has a very strong, emerging capability in biotech, including molecular marker technology. And it’s only continued to grow,” Graham said.
Alongside the academic foundation that sharpened his expertise in crop sciences, Illinois also offered an unparalleled network of collaborators and mentors — connections that would shape the trajectory of his career.
“All this was incredibly valuable as I progressed in my career: people to connect with, people to work with, and learning about the importance of how you think about people and teams in the workplace,” Graham said.
“There are three things that I ask everybody: How do you face big, hard scientific problems at scale? How do you make sure they address a farmer’s problem? And how do you enable that by working across teams to bring it to fruition? Those have been the things that I love to do, and some of the things that the University of Illinois helped me with as I began my career. ACES taught me that I love the technical part of the work that we do, but I also love the people part.”
After graduation, Graham began his career at Asgrow Seed Company. Following the company’s acquisition by Monsanto, he went on to serve as Director of Trait Field Solutions, Director of North America and Europe Plant Breeding, and eventually Vice President of Global Plant Breeding. 27 years after joining Asgrow, Graham is now the head of research and development at Bayer, which acquired Monsanto in 2018.
“Being in a position where I can think about both the next generation of product and solutions — but also how to help individuals and teams with their career or what they can achieve and how they can do more — has been so enjoyable for me,” Graham said.
“So far, I’ve spent a lot of time getting to know people in the organization, understanding where they are, what their concerns are, and what we could be doing better. I’ve also been learning a lot about crop protection, which is a big part of the organization today.”
Even as his career has advanced, Graham has remained closely connected to Illinois and the College of ACES, and indeed, the most historic research field in the U.S. “It was an easy decision to say, ‘Yes, let’s celebrate and commemorate the Morrow Plots,’” Graham said, referring to Bayer’s gift to revitalize the Morrow Plots in their 150th year.
For Graham, his time at ACES was an amazing moment in his career when “all the doors were wide open to explore and learn,” he said. “I hope current students will always take advantage of being and learning at Illinois, because nobody will ever say no. Be willing to share your perspectives and always be thoughtful about how it gets applied to solving problems.”
As the College of ACES celebrates 150 years of the Morrow Plots, we invite you to be part of this milestone year — attend events, explore the stories of discovery, and follow along as we look ahead to the next chapter of land-grant innovation. You can also make a lasting impact by supporting the Morrow Plots with a gift that helps preserve this living laboratory and advance research that serves farmers, communities, and global food systems for generations to come. Join us in celebrating — and investing in — the next 150 years.
A lot has changed on the University of Illinois Urbana-Champaign campus since its founding in 1867, but a storied plot of land near the south quad has been preserved nearly intact for a century and a half. The Morrow Plots, famed in song and story, represent the oldest continuously running agricultural experiment in North America, and are the second oldest in the world. And this year, they turn 150.
“The Morrow Plots are a huge part of our story in the College of ACES. They’re a direct example of how we live out our land-grant mission, providing evidence-based recommendations that serve the public,” said Germán Bollero, dean of the College of Agricultural, Consumer and Environmental Sciences at Illinois. “We’re so excited to celebrate 150 years of agricultural research and outreach that the Morrow Plots represent.”
It’s not an overstatement to say the Morrow Plots have directly impacted the way Americans farm. When the plots were established, farming was more of an art than a science. But methodical, controlled experiments in the plots proved certain practices — crop rotation and judicious fertilizer use — were winners for boosting crop yield, soil health, and farm profitability.
With the advent of University of Illinois Extension in 1914, another key milestone, results from the plots were shared with farmers to implement across the state and beyond.
“None of this would have been possible without the foresight of early campus leaders, who saw the value of long-term, practical research. This perspective allowed researchers to understand how farming practices shape soil, crops, and ecosystems over decades, not just seasons,” said Adam Davis, head of the Department of Crop Sciences, which oversees the Morrow Plots. “Together, these insights continue to inform strategies that sustain productivity while protecting natural resources.”
Something to Celebrate
In the centennial year of the experiment, the Morrow Plots were designated as a National Historic Landmark. In 2023, the plots’ data were digitized and made available online; the database includes crop hybrid, rotation, planting date and density, harvest date, and yield, as well as fertilizer type and amount.
The Morrow Plots today. Image by Andy Savage.
Now in 2026, the college celebrates the Morrow Plots’ 150th anniversary with a revitalized exterior, thanks to a gift from Bayer’s Crop Science division; a dedicated webcam where viewers can check out activities in the plots year-round; and a public tour and symposium scheduled for Oct. 28, along with other events throughout the year.
The October event will also formally unveil the Alma Mater Plots, an 80-acre parcel in the university’s south farms that carries the Morrow Plots’ research focus into the current era. A large focus of the Alma Mater Plots is accounting for tile drainage in cropping system performance, both as a tool and as a conduit for water and nutrient export.
“The Morrow Plots will be completing its 150th harvest this season. What will be the challenges facing agriculture in the next 150 harvests?” said crop sciences associate professor Andrew Margenot, director of the Morrow Plots and the Alma Mater Plots. “While we cannot anticipate the nature and extent of these challenges, we can design a long-term experiment that expands on the knowledge built from the Morrow Plots in a way that can flexibly address the challenges to come. In other words, it’s the ‘Morrow Plots 2.0.’”
Research and Extension in the College of ACES are made possible in part by Hatch and Smith-Lever funding, respectively, from USDA’s National Institute of Food and Agriculture.
October 3, 2025 | Pamela Smithwriting for Progressive Farmer
A 1-acre field of Flanagan silt loam located in the heart of the University of Illinois’ Champaign-Urbana campus is proof research can have a long arm.
Since 1876, the Morrow Plots have continuously provided insights on soil health, crop rotation and other aspects of agricultural productivity. The oldest agricultural experiment field in the United States and the second oldest in the world, the plot was dedicated as a National Historic Landmark in 1968.
So hallowed is the ground that legend has it the adjoining undergraduate library was built beneath ground to avoid casting a shadow on the crops. While some say that’s a myth, a song dedicated to the plot includes this cautioning reprise: “You can’t throw shade on the corn.”
HISTORY CLASS
Several historic field experiments continue to serve as a rich resource for scientists by providing archived samples and ongoing data collection on soil, crops and related cropping-system outcomes. England’s Rothamsted Research (Harpenden, Hertfordshire) site dates from 1843 and is considered the oldest continuing agricultural field experiment in the world, which served as the inspiration for the Morrow Plots.
A gift from Bayer’s Crop Science division will support the revitalization of the University of Illinois Urbana-Champaign‘s Morrow Plots, the oldest experimental agricultural fields in North America. Established in 1876, the plots have become a national symbol of agricultural innovation and remain a National Historic Landmark. The revitalization project will coincide with their 150th anniversary, with completion timed for sesquicentennial celebrations in 2026.
“This revitalization honors the extraordinary legacy of innovation that has defined the Morrow Plots for 150 years,” Bollero said. “We are deeply grateful to Bayer for investing in this project and for joining us in ensuring these fields remain a source of discovery and inspiration for generations to come.”
Overgrown shrubs that had surrounded and obscured views of the plots will be removed this fall to make way for a new landscape design. A live webcam will be set up to document progress.
“Bayer is honored to support the preservation of the Morrow Plots, which represent a cornerstone of agricultural research and innovation,” said Masha Trenhaile, head of university strategy and outreach at Bayer’s Crop Science division. “We see this project not only as an investment in a historic landmark, but also as a tribute to the scientific progress and partnerships that will carry agriculture forward.”
For Bayer and its Illinois alumni, the project underscores both a proud history and a vibrant future.
“The Morrow Plots are more than fields — they’re part of our identity as Illinois graduates and as agricultural innovators,” said Mike Graham, ACES alumnus and head of research and development for Bayer Crop Science. “For me personally, it’s an honor to help ensure this landmark is preserved and reimagined during its 150th year. When I was at ACES, all the doors were open to explore and learn, and I’m proud that Bayer can help provide that same inspiration for future generations.”
The Morrow Plots are stewarded by the Department of Crop Sciences in the College of ACES — under the leadership of department head Adam Davis and Andrew Margenot, associate professor of soil science and director of the Morrow Plots — to ensure the fields remain both a living laboratory for research and a symbol of Illinois’ enduring contributions to agriculture.
The revitalization work will continue throughout the 150th year of the Morrow Plots and be completed in time for the sesquicentennial celebrations in 2026. More details will be shared in the coming months, and the public can sign up for updates about the revitalization project and anniversary events.
To learn more about supporting this legacy and helping shape the next 150 years of agricultural innovation, please contact the College of ACES Office of Advancement at acesadvancement@illinois.edu or 217-333-9355.
May 24, 2023 | Jude Panliliowriting for The Daily Illini
When one thinks of iconic campus locations around the University, students typically consider the photogenic Main Quad or Alma Mater as contenders — the nondescript plots of farmland across from the Main Library might not be the first thing that comes to mind.
The importance of these titular Morrow Plots is almost always left a mystery until students run into the countless rumors that swirl about the ordinary-looking field.
“I know what they are because I have to walk past them sometimes,” said Akshar Goyal, freshman in Engineering. “I heard that if you walk on them, you would be immediately expelled.”
While the myths around the plots are colorful, with some considering a stroll through the fields at the stroke of midnight before graduation as the ultimate challenge, they pale in comparison to the Morrow Plots’ true significance to agricultural history and global farm innovation.
The Morrow Plots are America’s oldest, and the world’s second-oldest, continuous agricultural experiment. Founded in 1876 by professor Manly Miles, only nine years after the University was established, the plots were a hotbed of innovation in the field of agricultural science.
The discovery of many valuable agricultural breakthroughs, such as the positive effects of crop rotation on soil fertility, are credited to the plots. While only three of the original 10 plots remain, this recognized National Historic Landmark is still used for research to this very day.
“People don’t realize what a rare resource we have,” said Andrew Margenot, current head of the Morrow Plots Committee. “Very indirectly, lots of insights from the plots are broadly applicable to crop production anywhere in the world.”
In 1876, when University of Illinois professor Manly Miles established the Morrow Plots, he couldn’t have imagined the plots would become the oldest continuous agricultural experiment in the Western Hemisphere. Nor could he imagine, more than a century before the dawn of the internet, that the plots’ data would be digitized and made available online to scientists, students, and educators around the world.
The new database, which includes crop hybrid, rotation, planting density, and yield, as well as fertilizer type and amount, came together thanks to the Morrow Plots Data Curation Working Group, an interdisciplinary team from the College of Agricultural, Consumer and Environmental Sciences (ACES) and the University Library at U of I.
Data scientists and curators not only had to find the historical data, including in an ancient notebook held by the Department of Crop Sciences, they had to standardize it through time so that year-to-year comparisons could be made. For example, some data were missing for certain years and yield wasn’t recorded at all until 1888. Thankfully, the working group was up for the challenge.
Professor Sandi Lee Caldrone (left) joins research technician Maia Rothman (center) and Associate Director of Information Technology Josh Henry. Credit: Fred Zwicky / University of Illinois Urbana-Champaign
Sandi Caldrone, assistant professor and University Library research data librarian, says, “The data were all in slightly different formats and needed a lot of finagling to get them to line up. My role was doing the coding required to clean up and combine those data sets and get it ready to publish. I also did a lot of the accompanying documentation that explains how we did it for folks who want to use the data or reproduce our work.”
Josh Henry, associate director of information technology for ACES, initially kick-started the project in 2018 as an example for faculty wanting to curate their own research data. As few faculty have such long and complex datasets, he knew if the working group could pull it off with the Morrow Plots data, anyone could do it.
“We learned a lot of lessons about how to deal with really messy data,” Henry says. “We now feel confident explaining what challenges have to be met in order to take something that was perhaps less useful and turning it into something that will be valuable for the future.”
Prior to the database’s publication, Andrew Margenot was fielding dozens of requests for the Morrow Plots data each year. Now he can direct those requests to the Illinois Data Bank.
“I’ve gotten requests from government and university researchers, both in the U.S. and abroad. They’re mainly modelers trying to link weather patterns with yield and soil data; a lot of modelers salivate at the Morrow Plots data,” says Margenot, assistant professor in crop sciences. “We also get requests from folks trying to understand how their long-term trials compare with ours.”
Margenot says the data can also be used to understand how soil fertility is influenced by management practices of crop rotation and nutrient inputs, and how this relates to crop yields. After discovering a trove of historic soil samples from the Morrow Plots and other sites around Illinois, Margenot is eager to analyze long-term trends.
Caldrone hopes the data can also be used for educational purposes.
“Students in every field need to learn how to work with data now,” she says. “As instructors need to find datasets to work into their classes, I would love to see people using the Morrow Plots data. It’s a longitudinal data set, and I think students in any field can get a grasp of the basics of planting, fertilization, and yield. And then, for U of I students, they learn a little bit more about their university history.”
The Morrow Plots started as an experiment to test the effects of crop rotation on soil quality, but along the way, they helped establish a number of farming basics we take for granted today, including that crops require nitrogen, phosphorus, and potassium; hybrid corn can boost yield, especially when planted at close spacing; and crop rotation can mean less need for fertilizers.
“The lesson of the Morrow Plots is clear: conserve the soil and maintain proper soil fertility to sustain food production for future generations,” says Robert Dunker, ACES agronomist and field trials coordinator. “Results from the Morrow Plots have given insights on how crop production systems respond to rotation and soil fertility, shaping farming practices to this day. While the Morrow Plots have become a significant historical site, they remain a continuing opportunity for researchers and student education.”
February 12 | Holly Spangler writing for Farm Progress
Here’s what the oldest continuous experimental crop research field in the Western Hemisphere, founded in 1876, means for Illinois agriculture in 2023.
The Morrow Plots at the University of Illinois have inspired folklore, demonstrations and even a college song or two, but the historic plots hold significant research that helped develop crop production in the Midwest across the late 19th and much of the 20th centuries.
Established in 1876, the Morrow Plots are the oldest continuous experimental crop field in America, and the second oldest in the world, behind Rothamsted research station in England. Three of the 10 original plots — developed to test crop rotation — remain and are a protected National Historic Landmark.
Andrew Margenot, soil science assistant professor, chairs the Morrow Plots Committee and offers more insight into how Illinois agriculture has benefited from research on the plots.
What were the first Morrow Plots researchers trying to learn? At the time, they were looking at corn on corn or corn rotated with oats and clover, which was commonly raised back then for livestock like horses. Within about three decades, they went from looking at how rotating crops could improve yields to studying how nutrient inputs could improve yields. People weren’t really fertilizing with concentrated inputs until the 1900s, and they weren’t available at scale until after World War II; before then, it was largely manure.
That had to really change things. Yes. In 1904, they kicked off the second of five phases of the Morrow Plots that looked beyond crop rotations. That was looking at fertilizer inputs. Phase 3 was introducing hybrids and commercial fertilizers; phase 4 introduced soybeans to replace oats in the corn-oat rotation.
But their effect has been the same? Right. Long story short, the Morrow Plots have preserved their mission of looking at long-term effects on soils since 1876 of how we grow crops and how it affects yields.
Editor’s Note: This content (circa April 2003) originally appeared on an Agronomy Day webpage, which was rediscovered through the Internet Archive’s Wayback Machine. We appreciate any information to help us properly credit this history, which is one of the most complete found to date.
The Morrow Plots, which are located in the heart of the Urbana-Champaign campus of the University of Illinois, are the oldest continuous agricultural research fields in the United States. Established in 1876, they are predated only by the Rothamsted Field in England, which was started in 1843. The site was designated a National Historical Landmark by the Federal Government [and recognized as such during a dedication ceremony held] on Sept. 12, 1968.
During the dedication ceremony held in 1968, Professor M. B. Russell, then director of the Illinois Agricultural Experiment Station, noted that “it is of interest to observe that the Morrow Plots were established in 1876, the centennial year of one of the greatest proclamations of free men of all time, the Declaration of Independence.” He emphasized that “it is now clear that the lesson of the Morrow Plots represents a new kind of declaration of independence—not of political independence but independence from one of the fears that man has had since the dawn of time, the fear of hunger.”
David D. Henry, then U of I President, said that “this historic marker to be placed here is a reflection of the flowering of a magnificent concept upon which universities have been built and which today lies at the very essence of our own survival . . . I refer to the research function of universities, which results in the advancement of knowledge. I also refer to the precept of the land-grant university movement—to carry knowledge, old and new, into the field, the home, the office, and the community.”
Unlike most historic landmarks, the Morrow Plots remain today a working research site that promises to enhance our knowledge far into the future. Located in the heart of campus, the site reminds all visitors of the timeless truth of former U of I President Andrew Sloan Draper’s soil and her strength lies in its intelligent development.”
Beginnings
No one can answer the question of who actually started the Morrow Plots. The impetus most likely came from agricultural chemist C. W. Silver, who visited the Rothamsted Field while on-route to study for an advanced degree in Germany. Upon his return in 1875, he wrote of this experience in the campus newspaper. He concluded his write-up with a proposed layout for a long-term field study on corn.
Figure 1. Cyril Hopkins (right), head of the Department of Agronomy, and James H.Pettit (left), assistant in Soil Analysis at the Ag Experiment Station, take a soil sample from the Morrow Plots circa 1900. This photo may have been taken on April 11, 1904.
At the time, considerable controversy existed about the need for fertilizer in the soil. At least one leading USDA scientist believed that the soil in the Midwest was so high in total nutrients that it would never be necessary to add fertilizer if a crop rotation could be found that would “liberate” nutrients from the soil.
When the U of I was founded in 1868, Regent John Milton Gregory assumed responsibility for assembling the faculty. Manly Miles from Michigan State University, who was acknowledged as one of the most eminent agriculture professors in the country, was hired as Professor of Agriculture in 1875. On June 10, 1876, Miles wrote a letter to Prairie Farmer magazine describing a long-term experiment with corn that he had started. He also submitted a written proposal to Regent Gregory for experimental plots similar to those originally proposed by Professor Silver in the campus newspaper. The nature of the treatments described by Miles, however, were totally different from what is known about the early years of the Morrow Plots.
The first study at that site was known as the “Experiment 23 Rotation Study.” No crop yield data from the plot were reported until 1888. The first published yields from Experiment 23 for both 1888 and 1889 appeared in the Agricultural Experiment Station Bulletin for 1890. The 1888 date also coincides with the founding of the Illinois Agricultural Experiment Station. The report indicated that 10 half-acre plots had been planted during the previous 14 years, that the cropping systems were maintained as originally planned, and that no manure or fertilizers had been applied. Based on that record, the starting date for the Morrow Plots has been placed in 1876.
While Professors Silver and Miles both contributed to the founding of the experiment, the plots are named for George E. Morrow, appointed as Chair of Agriculture in 1876.
New Directions
Only three of the original 10 plots remain in place today. Two plots were lost for construction of the observatory in 1895 and five others were seeded back to lawn in 1903. The remaining three plots were reduced in size to 1/10th acre, subdivided, and separated by permanent borders at that time. The physical size and configuration of the three main plots has not changed since 1903.
Plot 3 has grown continuous corn since the beginning of the Morrow Plots. The two-year crop sequence study that started in 1876 continues today in plot 4, with soybeans having replaced oats in rotation with corn during 1976. Plot 5 was planted in a three-year rotation of corn, oats with alfalfa seeding, and a forage crop of alfalfa hay starting in 1904.
Over the years, the main plots have been further subdivided as selected practices have been updated to reflect changes in agronomic practices on Illinois farm fields. The first fertility treatment was added to the plots in 1904, in response to declines in crop yields that had occurred in all rotational sequences.
Before the start of the growing season that year, each of the main rotation plots were divided into four 1/20th-acre subplots. The north half of each plot remained untreated, while the southern halves were treated with agricultural limestone, manure, and either rock phosphate or bone phosphate. Crop yields increased in the southern halves of all plots in response to liming and fertilization.
In keeping with practices of the day, underground tiles were added to provide supplemental soil drainage. The soil on the Morrow Plots is classified as Flanagan silt loam. This nearly level, dark-colored soil developed over loam glacial till under prairie vegetation and has somewhat poor natural drainage without added tiles.
By 1955, nearly all growers in the state were using fertilizers as part of their normal planting practices. Concerns were raised at that time about whether unfertilized soil had been permanently damaged. As a result, the north and south plots were divided into quarters, with one subplot treated as agronomists would recommend that Illinois growers treat their fields. The crop yields immediately jumped to the same rate as most high-yielding fields in the state.
Beginning in the 1960s, corn plant populations were also changed each year to take full advantage of the fertility levels in the various subplots. Another major adjustment occurred in 1967 with a shift in plot 4 from a corn-and-oats rotation to a corn-and-soybean rotation. This rotation better reflected the change in farming practices taking place across the state of Illinois during that period.
The Key to Higher Yields
Corn was the leading crop in Illinois at the time the Morrow Plots were started. Today, the corn crop planted in the state has increased to more than 12 million acres and information on how to maintain high yields in corn is more important than ever for Illinois corn producers. Growing concerns about the impact of fertilizer use on the environment have also become a major focus of attention in recent years. Once again, the Morrow Plots are uniquely placed to help answer pressing concerns.
The long-term studies underway at the Morrow Plots on the impact of both fertilizer treatment and crop rotation on corn yield have proved particularly instructive in helping to shape agricultural practices. Comparison of corn yields in the Morrow Plots in relation to the crop sequence is possible only every six years, when all the plots are planted with corn. The most recent available data come from 1997.
In that year, continuous corn that had never been fertilized yielded only 54 bushels per acre. The two-year sequence of corn and soybean that had never been fertilized yielded 94 bushels per acre, and the three-year sequence of corn, oats, and hay reached 110 bushels per acre. The subplots treated with the “recommended” soil test level of fertilizer since 1955 jumped to 151 bushels per acre in continuous corn, to 191 bushels per acre in the two-year sequence, and to 200 bushels per acre in the three-year sequence. Yields were consistently the lowest in continuous corn and the highest in the three-year sequence, whether or not the soil was fertilized.
The results from crop sequence and fertilization are even more dramatic when compared with the average corn yield in the state over time. In the first few years of the experiment, the corn yield in the unfertilized subplots ranked close to the average yield in the state. Since then, the corn yield in those plots has remained well below the statewide average.
On the plots that were treated with fertilizer starting in 1904, corn yields increased steadily through the 1970s. By 1978, the yields were approximately three times those of 1904 in all three cropping systems. On the other plots that received “recommended” levels of fertilizer starting in 1955, the yields almost immediately rose above the Illinois average and have remained so until today. Evidence accumulated since also indicates that larger differences in corn yield are caused by the soil treatments than by the cropping sequence.
During the last 30 years, yields have held fairly constant in all except the plots receiving both the manure and lime treatments and the recommended nitrogen, potassium, and phosphorus treatment. Weather patterns of the region may have contributed to these trends. Wet spring weather and cool temperatures in the 1990s reversed a trend toward earlier planting that began in the 1940s. Since 1967, yield has increased during years with warm spring weather and cool moist summers.
Taken together, this data from the Morrow Plots represents more than 100 years of accumulated knowledge on the effect of both sound and unsound crop management practices on corn yield. Most importantly, it has helped to establish the importance of crop rotation and fertilizer treatments in the modern agricultural system that has allowed us to so successfully feed an ever-increasing world population.
Changes in the Soil
Besides crop yield, the other major item of interest for the Morrow Plots is the changing level of soil organic matter in relation to the cropping sequence and fertilizer application. In dark-colored soils, such as Flanagan silt loam, cropping reduces soil organic matter. Organic matter, which is derived from plant and, to a lesser extent, animal residues, is composed of carbon, oxygen, hydrogen, and trace amounts of minerals.
Figure 2. A glass jar of soil from the Morrow Plots that was given to college donors in 1994.
Unfortunately, there are no archival soil or chemical data showing the conditions that existed when the study started in 1876. The earliest surviving soil samples, which date from 1904, were stored in glass jars. The study had already been underway for 28 years by the time these samples were taken.
The grass borders, however, may well approximate the original soil organic matter content of the plots. Values range from 5.5 percent organic matter on the west border to 6.5 percent on the east border. With an assumed starting level of about 6.0 percent organic matter, the soil in the continuous corn plot had dropped to 4.1 percent by 1904. The two-year rotation of corn and oats measured about 4.5 percent organic matter, and the three-year sequence of corn, oats, and hay was measured at about 5.9 percent, indicating a differential drop in organic matter related to the crop sequence.
Soil samples have been collected at least at 10-year intervals since 1904. Soil organic matter contents have been consistently higher in plots under the corn, oats, and hay sequence than in soils under the other two cropping systems. In plots where no fertilizer has been applied, the organic matter content first declined rapidly and then continued to decline at a slower rate under all cropping systems.
Organic matter level losses have generally occurred more slowly in south plots treated with manure. The only plots that no longer appear to be losing organic matter are the two- and three-year rotation plots that are treated with both the manure and inorganic fertilizer. Those trends in organic matter are difficult to assess statistically because none of the fertilizer treatments is replicated within the main rotation treatment and organic matter levels are known to vary within the experimental area.
A comparison of selected soil test data for 1997 and archival samples from 1913 show an overall decline in soil test phosphorus level, which is probably due to crop removal. A slight corresponding increase in soil pH and soil potassium levels has probably resulted from weathering.
Results from the Morrow Plots clearly demonstrate the positive relationship between crop yield response and soil organic matter levels. The composition or characteristics of organic matter may contribute more to soil quality than the quantity of organic material in the soil. In the Morrow Plots, the size and metabolic function of the microbial communities, as well as the amount and composition of particulate organic matter and of amino sugars, has been influenced by the crop rotation and fertility treatments. Ongoing investigations may succeed in relating some of these characteristics to specific aspects of soil performance
A Century of Knowledge
The need to protect this invaluable source of data stretching back more than 120 years has been well recognized over the years. The Undergraduate Library, which is located directly to the west of the plots, was built underground so as not to disturb the physical setting of the plots. In 2000, the efforts of Ted Peck, then professor of soil fertility, resulted in the considerable modification of plans for a nearby facility so as to minimize the impact on the Morrow Plots.
Despite its world renown, the Morrow Plots has operated without a designated director and has been open to all faculty within what today is the College of Agricultural, Consumer and Environmental Sciences. Over the years, it has been closely associated with a long list of eminent researchers from the College. To them and to C. W. Silver, Manley Miles, and George E. Morrow, the agricultural community owes a debt of gratitude for making possible the many lessons that have been learned from the Morrow Plots. Future generations will benefit from these lessons and hopefully from new, updated, and improved long-term experiments that the Morrow Plots have inspired.
