A study led by Iowa State University reports on Apr. 28 that carbon inputs from maize residue in the U.S. Corn Belt increased by almost 50 percent between 1980 and 2020. The increase is attributed to higher corn yields and expanded acreage, raising questions about future crop management, farm economics, and environmental practices.
Researchers say this shift may require changes in how farmers manage their fields. “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 of the study who recently completed his doctoral degree at Iowa State University and now works at Corteva Agriscience.
The team analyzed data from field experiments across eleven states and public records to estimate county-level maize residue amounts over four decades. They found that about three-quarters of the biomass increase was due to improved yields while roughly one-quarter came from planting more corn, as detailed in their publication in Communications Earth & Environment.
Slobodan Trifunovic, co-author of the paper and insights analytics lead at Bayer Crop Science, said: “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.” Despite being a major source of soil carbon after harvest, only part of this biomass becomes stable organic matter; much is released as atmospheric carbon dioxide or used for livestock feed or bioenergy products.
According to estimates by the authors, current maize residue produced could be valued above $14 billion within carbon markets but such markets are not always accessible for all farmers. High levels of leftover crop material offer both benefits—such as erosion control—and challenges like delayed spring planting or increased fertilizer needs depending on local conditions. Study co-author Sotirios Archontoulis said: “The extent to which greater residue is a plus or a minus depends on location and subsequent crop… Most importantly, this level of change has significant implications for crop management, economics and the environment. It deserves serious attention.”
J.D. Rossouw with Bayer Crop Science added: “We already knew plant breeding contributions to yields, but this research also highlights the power of plant breeding to create more sustainable agricultural systems… 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.”
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