Apr 15, 2025 - News

Iowa research challenges crop rotation assumptions

Jason Clayworth

A photo of a farm. — Researchers have studied long-term rotations of crops at Marsden Farm for more than two decades. Photo: David Sunberg/Iowa State University

Rotating crops fertilized with livestock manure does not increase soil carbon levels, according to preliminary results of an ongoing study from Iowa State University.

Why it matters: The findings counter long-standing assumptions and could have implications for carbon-market initiatives designed to help mitigate climate change, ISU's news service reports.

They come as ISU tests whether skipping crop rotation practices could increase soybean farmers' profits.

Zoom in: ISU's study reviews whether crop rotations help plants store more carbon dioxide in soil to prevent the gas from entering the atmosphere and contributing to climate change.

Studies, which have been ongoing at a farm near Boone since 2001, tested multiple rotation practices and found carbon sequestration levels unchanged.

Yes, but: The rotations still have a positive climate impact, the news service reports.

That's because they produce the form of nitrogen necessary for crops to thrive, reducing reliance on synthetic fertilizers that emit nitrous oxide, a potent heat-trapping gas.

The bottom line: Crop rotation practices still hold value, even if they're not as extensive as previously believed.

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Iowa research challenges crop rotation assumptions

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