Ames, Iowa, USA
April 28, 2026
Tractor and tillage equipment prepare a field in spring before planting the next crop. Photo courtesy of Alejo Ruiz.
Carbon inputs from maize residue in the Corn Belt increased almost 50% from 1980 to 2020, according to a new Iowa State University-led study. The increase, driven by higher productivity and expanded corn acreage, has significant implications for crop management, farm economics and environmental sustainability across the region.
“This represents a big change in crop production systems that suggests the need for a readjustment of other management practices,” said Alejo Ruiz, lead researcher on the study who recently earned his doctoral degree in crop production and physiology at Iowa State and is now a scientist with Corteva Agriscience.
To measure the changes, the research team synthesized data from widespread field experiments and public U.S. Department of Agriculture data to estimate maize residue quantity and quality at the county level in the U.S. Corn Belt. They conducted 31 field experiments in 11 states and dissected more than 20,000 plants. Each field experiment involved testing 18 to 24 corn hybrids commercialized between 1980 and 2020.
Their findings were recently published in the journal Communications Earth & Environment. They believe the study represents the most comprehensive collection of maize end-of-season biomass and residue-related data available in the U.S.
The paper credits 77% of the biomass increase to higher corn yields and 23% to the expansion of corn acreage over the four decades.
“This research and the data collected matter because we now have a better understanding of the potential for corn residue in capturing carbon. More research will be needed to further unpack and understand the relationship between how carbon is captured and then, how it can be ultimately preserved,” said Slobodan Trifunovic, a co-author on the paper. Trifunovic is the insights analytics and regenerative agriculture lead at Bayer Crop Science, which helped fund the study in partnership with the Foundation for Food and Agricultural Research.
Although biomass left after corn harvest represents the largest source of soil carbon, only a fraction ends up in the stabilized organic carbon form closely linked to soil health. More leaves the field as atmospheric carbon dioxide. What happens to the rest?
A portion of the remaining residue can be harvested for uses on and off the farm, including as livestock feed and bedding or as material for construction or bioenergy products. The authors estimate that today’s maize residue produced in the Corn Belt is worth more than $14 billion in carbon markets. However, carbon markets are not available or practical for farmers in all areas.
Currently, much of the crop residue stays in the field, where it presents benefits and challenges.
Farmers have long been encouraged to use conservation tillage practices that leave residue on the soil surface to protect it from erosion. However, high residue levels can pose problems for no-till planting and planting of cover crops. Surface residue can also slow down soil warming and drying in the spring, delaying planting the next cash crop and risking yield declines. High levels of residue can also increase the need for nitrogen fertilizer in some years.
"The extent to which greater residue is a plus or a minus depends on location and subsequent crop,” said study co-author Sotirios Archontoulis, Pioneer Hy-Bred Professor of Agronomy at Iowa State. "Most importantly, this level of change has significant implications for crop management, economics and the environment. It deserves serious attention."
As a result, the researchers recommend that more attention be given to optimizing residue management, along with other farm management practices, including fertility programs and timing of planting to maximize productivity and sustainability.
“We already knew plant breeding contributions to yields, but this research also highlights the power of plant breeding to create more sustainable agricultural systems,” said J.D. Rossouw, senior vice president and global plant breeding lead with Bayer Crop Science. “With continuous advances in plant breeding, farmers can look forward to solutions that offer them more options and greater flexibility in their farming practices, while also helping to reduce environmental impacts.”
Contributors to the study also included:
- Michael Castellano, William T. Frankenberger Professorship in Soil Science, and Lead, Iowa Nitrogen Initiative;
- Dan Northrup, affiliate assistant professor, agronomy, Iowa State;
- Antonella Ferela and Brandin Gambin, research scientists, agronomy, Iowa State;
- Gerasimos J.N. Danalatos, former PhD student, agronomy, Iowa State;
- Tomas Della Chiesa, research scientist, Universidad de Buenos Aires;
- Douglas Eudy, scientist, Bayer Crop Science.
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